Merge branch 'fix/rolling-time-ordering'

Add socket routing configuration for interface binding, packet marks, and FreeBSD FIB selection.

.gitea/workflows/ci.yml

@@ -7,7 +7,6 @@ on:
   pull_request:
     branches:
       - main
-  merge_group:
   workflow_dispatch:
 
 permissions:
@@ -29,10 +28,10 @@ jobs:
           persist-credentials: false
 
       - name: Install Rust toolchain
-        uses: actions-rust-lang/setup-rust-toolchain@166cdcfd11aee3cb47222f9ddb555ce30ddb9659 # v1
+        uses: actions-rust-lang/setup-rust-toolchain@ecabd13d1c56bd1345c230e542e9144811ad706f # v2
         with:
           components: rustfmt
-          cache-key: fmt
+          cache: false
 
       - name: Check formatting
         uses: actions-rust-lang/rustfmt@4066006ec54a31931b9b1fddfd38f2fdf2d27143 # v1
@@ -49,10 +48,10 @@ jobs:
           persist-credentials: false
 
       - name: Install Rust toolchain
-        uses: actions-rust-lang/setup-rust-toolchain@166cdcfd11aee3cb47222f9ddb555ce30ddb9659 # v1
+        uses: actions-rust-lang/setup-rust-toolchain@ecabd13d1c56bd1345c230e542e9144811ad706f # v2
         with:
           components: clippy
-          cache-key: clippy
+          cache: false
 
       - name: Run clippy
         run: |
@@ -79,46 +78,22 @@ jobs:
       matrix:
         include:
           - task: check
-            runner: ubuntu-24.04
             target: x86_64-unknown-linux-gnu
             musl: false
 
           - task: test
-            runner: ubuntu-24.04
             target: x86_64-unknown-linux-gnu
             musl: false
 
           - task: check
-            runner: ubuntu-24.04
             target: x86_64-unknown-linux-musl
             musl: true
 
           - task: test
-            runner: ubuntu-24.04
             target: x86_64-unknown-linux-musl
             musl: true
 
-          - task: check
-            runner: ubuntu-24.04-arm
-            target: aarch64-unknown-linux-gnu
-            musl: false
-
-          - task: test
-            runner: ubuntu-24.04-arm
-            target: aarch64-unknown-linux-gnu
-            musl: false
-
-          - task: check
-            runner: ubuntu-24.04-arm
-            target: aarch64-unknown-linux-musl
-            musl: true
-
-          - task: test
-            runner: ubuntu-24.04-arm
-            target: aarch64-unknown-linux-musl
-            musl: true
-
-    runs-on: ${{ matrix.runner }}
+    runs-on: ubuntu-latest
     timeout-minutes: 25
 
     steps:
@@ -134,10 +109,10 @@ jobs:
           sudo apt-get install --no-install-recommends musl-tools
 
       - name: Install Rust toolchain
-        uses: actions-rust-lang/setup-rust-toolchain@166cdcfd11aee3cb47222f9ddb555ce30ddb9659 # v1
+        uses: actions-rust-lang/setup-rust-toolchain@ecabd13d1c56bd1345c230e542e9144811ad706f # v2
         with:
           target: ${{ matrix.target }}
-          cache-key: ${{ matrix.task }}-${{ matrix.target }}
+          cache: false
 
       - name: Run ${{ matrix.task }} with all features
         run: |
@@ -172,9 +147,9 @@ jobs:
           persist-credentials: false
 
       - name: Install Rust toolchain
-        uses: actions-rust-lang/setup-rust-toolchain@166cdcfd11aee3cb47222f9ddb555ce30ddb9659 # v1
+        uses: actions-rust-lang/setup-rust-toolchain@ecabd13d1c56bd1345c230e542e9144811ad706f # v2
         with:
-          cache-key: docs
+          cache: false
 
       - name: Check docs
         run: |
@@ -183,3 +158,6 @@ jobs:
             --all-features \
             --no-deps \
             --locked
+
+      - name: Run doctests
+        run: cargo test --workspace --doc --all-features --locked

.gitea/workflows/docker-publish.yml

@@ -0,0 +1,99 @@
+name: Publish irtt-server image
+
+on:
+  push:
+    tags:
+      # This repo tags each crate independently (irtt-proto/vX, irtt-client/vX,
+      # ...); only the app package's tag corresponds to this image.
+      - "irtt-rs/v*"
+  workflow_dispatch:
+
+env:
+  IMAGE_NAME: irtt-server
+  IMAGE_OWNER: lochnair
+  GITEA_REGISTRY: git.lochnair.net
+  GHCR_REGISTRY: ghcr.io
+  # Pinned so a floating "latest" release doesn't silently change the build.
+  CRANE_VERSION: v0.20.2
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
+
+      - name: Determine image tags
+        id: meta
+        run: |
+          if [ "${GITHUB_REF_TYPE}" = "tag" ]; then
+            version="${GITHUB_REF_NAME#irtt-rs/v}"
+            echo "version=${version}" >> "$GITHUB_OUTPUT"
+            echo "tags=${version},latest" >> "$GITHUB_OUTPUT"
+          else
+            # Manual dispatch off a branch: tag by commit only, never touch
+            # "latest", so an ad-hoc build can't clobber the last release.
+            version="sha-$(git rev-parse --short HEAD)"
+            echo "version=${version}" >> "$GITHUB_OUTPUT"
+            echo "tags=${version}" >> "$GITHUB_OUTPUT"
+          fi
+
+      # Cross-compilation is handled inside the Dockerfile via tonistiigi/xx
+      # (native builds, no emulation), but buildx still needs a driver that
+      # can assemble a multi-platform manifest list.
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@f87e5991a6d7451dcb8d9637bfbc97413f497069 # v4
+
+      - name: Log in to Gitea Container Registry
+        uses: docker/login-action@dbcb813823bdd20940b903addbd779551569679f # v4
+        with:
+          registry: ${{ env.GITEA_REGISTRY }}
+          # The automatic per-job token comes back unauthorized for package
+          # writes on this instance, so use a PAT (scope: write:package) instead.
+          # (Secret names can't start with GITEA_/GITHUB_, hence REGISTRY_*.)
+          username: ${{ secrets.REGISTRY_USERNAME }}
+          password: ${{ secrets.REGISTRY_TOKEN }}
+
+      - name: Log in to GHCR
+        uses: docker/login-action@dbcb813823bdd20940b903addbd779551569679f # v4
+        with:
+          registry: ${{ env.GHCR_REGISTRY }}
+          username: ${{ secrets.GHCR_USERNAME }}
+          password: ${{ secrets.GHCR_TOKEN }}
+
+      - name: Build tag list
+        id: tags
+        run: |
+          IFS=',' read -ra tag_list <<< "${{ steps.meta.outputs.tags }}"
+          gitea_tags=""
+          for t in "${tag_list[@]}"; do
+            gitea_tags="${gitea_tags}${GITEA_REGISTRY}/${IMAGE_OWNER}/${IMAGE_NAME}:${t},"
+          done
+          echo "gitea=${gitea_tags%,}" >> "$GITHUB_OUTPUT"
+
+      # Gitea is the primary publish target: this is the only build. Every
+      # other registry gets an exact digest copy of this same image (see
+      # below), never a separate build, so the hash matches everywhere.
+      - name: Build and push to Gitea
+        id: build
+        uses: docker/build-push-action@c3c9e263c25d99ce0380d002d59b67737d91b0dc # v7
+        with:
+          context: .
+          platforms: linux/amd64,linux/arm64
+          push: true
+          tags: ${{ steps.tags.outputs.gitea }}
+
+      - name: Install crane
+        run: |
+          mkdir -p "${HOME}/.local/bin"
+          curl -sL "https://github.com/google/go-containerregistry/releases/download/${CRANE_VERSION}/go-containerregistry_Linux_x86_64.tar.gz" \
+            | tar -xz -C "${HOME}/.local/bin" crane
+          echo "${HOME}/.local/bin" >> "$GITHUB_PATH"
+
+      - name: Duplicate image to GHCR (same digest, no rebuild)
+        run: |
+          source_ref="${GITEA_REGISTRY}/${IMAGE_OWNER}/${IMAGE_NAME}@${{ steps.build.outputs.digest }}"
+          IFS=',' read -ra tag_list <<< "${{ steps.meta.outputs.tags }}"
+          for t in "${tag_list[@]}"; do
+            crane copy "${source_ref}" "${GHCR_REGISTRY}/${IMAGE_OWNER}/${IMAGE_NAME}:${t}"
+          done

.gitea/workflows/fuzz.yml

@@ -1,4 +1,4 @@
-name: Proto Fuzz Smoke
+name: Fuzz Smoke
 
 on:
   push:
@@ -16,6 +16,9 @@ env:
   CARGO_TERM_COLOR: always
   # Pinned for reproducibility; bump deliberately alongside `fuzz/Cargo.lock`.
   CARGO_FUZZ_VERSION: 0.13.1
+  CARGO_FUZZ_SHA256: 86edc9b8f20c29ff07c3e5fcd67bc3f0784b3b960a5428635060f20d50555461
+  FUZZ_TOOLCHAIN: nightly-x86_64-unknown-linux-gnu
+  FUZZ_TARGET: x86_64-unknown-linux-gnu
 
 jobs:
   fuzz-smoke:
@@ -30,24 +33,35 @@ jobs:
           persist-credentials: false
 
       - name: Install stable Rust toolchain
-        uses: actions-rust-lang/setup-rust-toolchain@166cdcfd11aee3cb47222f9ddb555ce30ddb9659 # v1
+        uses: actions-rust-lang/setup-rust-toolchain@ecabd13d1c56bd1345c230e542e9144811ad706f # v2
         with:
-          cache-key: fuzz
+          cache: false
 
       - name: Install nightly Rust toolchain
         # Installed alongside, but deliberately not made the directory
         # default: cargo-fuzz itself is built with the default stable
         # toolchain below, and only `fuzz build`/`fuzz run` are run with
-        # `+nightly`. Building cargo-fuzz's own dependency tree under a
-        # nightly override can trip build scripts (e.g. rustix) that gate
+        # the GNU-host nightly below. Building cargo-fuzz's own dependency
+        # tree under a nightly override can trip build scripts (e.g. rustix) that gate
         # unstable internal attributes on detecting a nightly compiler.
-        run: rustup toolchain install nightly --profile minimal --no-self-update
+        run: rustup toolchain install "${FUZZ_TOOLCHAIN}" --profile minimal --no-self-update
 
       - name: Install cargo-fuzz
-        run: cargo install cargo-fuzz --locked --version "${CARGO_FUZZ_VERSION}"
+        run: |
+          set -euo pipefail
+          archive="cargo-fuzz-${CARGO_FUZZ_VERSION}-x86_64-unknown-linux-musl.tar.gz"
+          curl --fail --show-error --location --retry 3 \
+            "https://github.com/rust-fuzz/cargo-fuzz/releases/download/${CARGO_FUZZ_VERSION}/${archive}" \
+            --output "$archive"
+          echo "${CARGO_FUZZ_SHA256}  ${archive}" | sha256sum --check --status -
+          tar -xzf "$archive" cargo-fuzz
+          install -Dm755 cargo-fuzz "${RUNNER_TEMP}/bin/cargo-fuzz"
+          echo "${RUNNER_TEMP}/bin" >> "$GITHUB_PATH"
 
       - name: Build all fuzz targets
-        run: cargo +nightly fuzz build
+        # libFuzzer sanitizers require dynamically linked GNU binaries; the
+        # runner's default Rust host can be static musl.
+        run: RUSTUP_TOOLCHAIN="${FUZZ_TOOLCHAIN}" cargo fuzz build --target "${FUZZ_TARGET}"
         working-directory: fuzz
 
       - name: Run bounded fuzz smoke for every target
@@ -57,9 +71,9 @@ jobs:
         # regression; this is not meant to be exhaustive fuzzing.
         run: |
           set -euo pipefail
-          for target in decode_request decode_open_reply decode_echo_reply decode_params decode_varint; do
+          for target in decode_request decode_open_reply decode_echo_reply decode_params decode_varint server_core_datagrams; do
             echo "::group::fuzz smoke: ${target}"
-            cargo +nightly fuzz run "${target}" -- \
+            RUSTUP_TOOLCHAIN="${FUZZ_TOOLCHAIN}" cargo fuzz run --target "${FUZZ_TARGET}" "${target}" -- \
               -max_total_time=10 \
               -timeout=5
             echo "::endgroup::"

.gitea/workflows/interop-netem.yml

@@ -30,15 +30,16 @@ jobs:
           persist-credentials: false
 
       - name: Install Rust toolchain
-        uses: actions-rust-lang/setup-rust-toolchain@166cdcfd11aee3cb47222f9ddb555ce30ddb9659 # v1
+        uses: actions-rust-lang/setup-rust-toolchain@ecabd13d1c56bd1345c230e542e9144811ad706f # v2
         with:
-          cache-key: interop-netem
+          cache: false
 
-      - name: Check host tools
+      - name: Check host tools and network administration access
         run: |
           ip -V
           tc -V
           go version
+          sudo -n true
 
       - name: Install upstream irtt
         run: |
@@ -62,14 +63,14 @@ jobs:
         run: |
           latest_summary="$(find target/interop-netem -mindepth 2 -maxdepth 2 -name github-step-summary.md -type f -print 2>/dev/null | sort | tail -n 1)"
           if [ -n "$latest_summary" ]; then
-            cat "$latest_summary" >> "$GITHUB_STEP_SUMMARY"
+            cat "$latest_summary" >> "$GITEA_STEP_SUMMARY"
           else
-            echo "No netem interop github-step-summary.md found." >> "$GITHUB_STEP_SUMMARY"
+            echo "No netem interop github-step-summary.md found." >> "$GITEA_STEP_SUMMARY"
           fi
 
       - name: Upload netem interop artifacts
         if: always()
-        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7
+        uses: https://gitea.com/actions/gitea-upload-artifact@v7
         with:
           name: interop-netem
           path: target/interop-netem

.gitea/workflows/semver.yml

@@ -0,0 +1,52 @@
+name: Semver
+
+on:
+  workflow_dispatch:
+  push:
+    tags:
+      - "irtt-proto/v*.*.*"
+      - "irtt-client/v*.*.*"
+      - "irtt-server/v*.*.*"
+      - "irtt-stats/v*.*.*"
+      - "irtt-rs/v*.*.*"
+
+permissions:
+  contents: read
+
+env:
+  CARGO_SEMVER_CHECKS_VERSION: 0.50.0
+  CARGO_SEMVER_CHECKS_SHA256: 52a65dc88dc53fa8b57d6087954eb52cda149ca03bcfca78ce3fdecd23f893c4
+
+jobs:
+  semver:
+    name: cargo-semver-checks
+    runs-on: ubuntu-latest
+    timeout-minutes: 20
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
+        with:
+          persist-credentials: false
+
+      - name: Install Rust toolchain
+        uses: actions-rust-lang/setup-rust-toolchain@ecabd13d1c56bd1345c230e542e9144811ad706f # v2
+        with:
+          cache: false
+
+      # The CLI preserves the previous wrapper's `feature-group: all-features`
+      # behavior without its GitHub API/cache dependency.
+      - name: Install cargo-semver-checks
+        run: |
+          set -euo pipefail
+          archive="cargo-semver-checks-x86_64-unknown-linux-gnu.tar.gz"
+          curl --fail --show-error --location --retry 3 \
+            "https://github.com/obi1kenobi/cargo-semver-checks/releases/download/v${CARGO_SEMVER_CHECKS_VERSION}/${archive}" \
+            --output "$archive"
+          echo "${CARGO_SEMVER_CHECKS_SHA256}  ${archive}" | sha256sum --check --status -
+          tar -xzf "$archive" cargo-semver-checks
+          install -Dm755 cargo-semver-checks "${RUNNER_TEMP}/bin/cargo-semver-checks"
+          echo "${RUNNER_TEMP}/bin" >> "$GITHUB_PATH"
+
+      - name: Check semver compatibility
+        run: cargo semver-checks check-release --all-features

.gitea/workflows/supply-chain.yml

@@ -0,0 +1,109 @@
+name: Supply chain
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+  schedule:
+    - cron: "41 2 * * 1"
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+env:
+  ACTIONLINT_VERSION: 1.7.7
+  CARGO_DENY_VERSION: 0.20.2
+  CARGO_DENY_SHA256: 9f12ed4c49936e09b48bf862b595cde2fe64fcbd9d74dfacac6131ca824c8d5f
+  ACTIONLINT_SHA256: 023070a287cd8cccd71515fedc843f1985bf96c436b7effaecce67290e7e0757
+
+jobs:
+  cargo-deny:
+    name: cargo-deny ${{ matrix.checks }}
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          # Advisories can appear after code was merged. Keep this visible,
+          # but don't let a surprise upstream advisory nuke every unrelated PR.
+          - checks: advisories
+            continue-on-error: true
+
+          # These are policy choices in this repo. They should block PRs.
+          - checks: bans licenses sources
+            continue-on-error: false
+
+    continue-on-error: ${{ matrix.continue-on-error }}
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
+        with:
+          persist-credentials: false
+
+      - name: Install cargo-deny
+        run: |
+          set -euo pipefail
+          archive="cargo-deny-${CARGO_DENY_VERSION}-x86_64-unknown-linux-musl.tar.gz"
+          curl --fail --show-error --location --retry 3 \
+            "https://github.com/EmbarkStudios/cargo-deny/releases/download/${CARGO_DENY_VERSION}/${archive}" \
+            --output "$archive"
+          echo "${CARGO_DENY_SHA256}  ${archive}" | sha256sum --check --status -
+          tar -xzf "$archive" --strip-components=1 \
+            "cargo-deny-${CARGO_DENY_VERSION}-x86_64-unknown-linux-musl/cargo-deny"
+          install -Dm755 cargo-deny "${RUNNER_TEMP}/bin/cargo-deny"
+          echo "${RUNNER_TEMP}/bin" >> "$GITHUB_PATH"
+
+      - name: Run cargo-deny
+        run: >-
+          cargo deny --manifest-path Cargo.toml --all-features check
+          ${{ matrix.checks }}
+
+  actionlint:
+    name: actionlint
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
+        with:
+          persist-credentials: false
+
+      - name: Install actionlint
+        run: |
+          set -euo pipefail
+          archive="actionlint_${ACTIONLINT_VERSION}_linux_amd64.tar.gz"
+          curl --fail --show-error --location --retry 3 \
+            "https://github.com/rhysd/actionlint/releases/download/v${ACTIONLINT_VERSION}/${archive}" \
+            --output "$archive"
+          echo "${ACTIONLINT_SHA256}  ${archive}" | sha256sum --check --status -
+          tar -xzf "$archive" actionlint
+          install -Dm755 actionlint "${RUNNER_TEMP}/bin/actionlint"
+          echo "${RUNNER_TEMP}/bin" >> "$GITHUB_PATH"
+
+      - name: actionlint handwritten workflows
+        # actionlint validates GitHub Actions syntax. It cannot parse Gitea's
+        # required absolute action URL in interop-netem.yml, so that workflow
+        # is checked by the Gitea runner instead.
+        run: |
+          actionlint \
+            .gitea/workflows/ci.yml \
+            .gitea/workflows/docker-publish.yml \
+            .gitea/workflows/fuzz.yml \
+            .gitea/workflows/semver.yml \
+            .gitea/workflows/supply-chain.yml \
+            .github/workflows/actions-security.yml \
+            .github/workflows/ci-arm.yml \
+            .github/workflows/osv-scanner.yml \
+            .github/workflows/rust-clippy.yml
+
+      - name: actionlint generated release workflow
+        run: >-
+          actionlint -shellcheck= .github/workflows/irtt-rs-release.yml

.github/workflows/actions-security.yml

@@ -16,34 +16,6 @@ permissions:
   contents: read
 
 jobs:
-  actionlint:
-    name: actionlint
-    runs-on: ubuntu-latest
-    timeout-minutes: 10
-
-    steps:
-      - name: Checkout
-        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
-        with:
-          persist-credentials: false
-
-      - name: actionlint handwritten workflows
-        uses: raven-actions/actionlint@205b530c5d9fa8f44ae9ed59f341a0db994aa6f8
-        with:
-          files: >-
-            .github/workflows/actions-security.yml,
-            .github/workflows/ci.yml,
-            .github/workflows/interop-netem.yml,
-            .github/workflows/osv-scanner.yml,
-            .github/workflows/rust-clippy.yml,
-            .github/workflows/semver.yml,
-            .github/workflows/supply-chain.yml
-
-      - name: actionlint generated release workflow
-        uses: raven-actions/actionlint@205b530c5d9fa8f44ae9ed59f341a0db994aa6f8
-        with:
-          files: .github/workflows/irtt-rs-release.yml
-          shellcheck: false
   zizmor:
     name: zizmor
     runs-on: ubuntu-latest
@@ -60,7 +32,13 @@ jobs:
         with:
           persist-credentials: false
 
+      # Zizmor's SARIF integration publishes GitHub Code Scanning results.
+      # It remains here while portable actionlint runs with Gitea CI, but scans
+      # both workflow directories through its GitHub Actions rule set.
       - name: Run zizmor
-        uses: zizmorcore/zizmor-action@3dc1ecc9bcb9e94e9b2c709687979e1298497054 # v0.6.2
+        uses: zizmorcore/zizmor-action@cc914d7f3750a2d13d75c7f184a1060aa0e9d482 # v0.6.4
         with:
           persona: regular
+          inputs: |
+            .github/workflows
+            .gitea/workflows

.github/workflows/ci-arm.yml

@@ -0,0 +1,80 @@
+name: Rust ARM CI
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+  merge_group:
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  verify:
+    name: cargo ${{ matrix.task }} (${{ matrix.target }})
+    # Gitea currently has only amd64 Linux runners; retain ARM coverage here.
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - task: check
+            target: aarch64-unknown-linux-gnu
+            musl: false
+
+          - task: test
+            target: aarch64-unknown-linux-gnu
+            musl: false
+
+          - task: check
+            target: aarch64-unknown-linux-musl
+            musl: true
+
+          - task: test
+            target: aarch64-unknown-linux-musl
+            musl: true
+
+    runs-on: ubuntu-24.04-arm
+    timeout-minutes: 25
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
+        with:
+          persist-credentials: false
+
+      - name: Install musl toolchain
+        if: matrix.musl
+        run: |
+          sudo apt-get update
+          sudo apt-get install --no-install-recommends musl-tools
+
+      - name: Install Rust toolchain
+        uses: actions-rust-lang/setup-rust-toolchain@ecabd13d1c56bd1345c230e542e9144811ad706f # v2
+        with:
+          target: ${{ matrix.target }}
+          cache-key: ${{ matrix.task }}-${{ matrix.target }}
+
+      - name: Run ${{ matrix.task }} with all features
+        run: |
+          cargo ${{ matrix.task }} \
+            --workspace \
+            --all-targets \
+            --all-features \
+            --target ${{ matrix.target }} \
+            --locked
+
+      - name: Run ${{ matrix.task }} without default features
+        run: |
+          cargo ${{ matrix.task }} \
+            --workspace \
+            --all-targets \
+            --no-default-features \
+            --target ${{ matrix.target }} \
+            --locked

.github/workflows/osv-scanner.yml

@@ -31,7 +31,7 @@ permissions:
 jobs:
   scan-scheduled:
     if: ${{ github.event_name == 'push' || github.event_name == 'schedule' }}
-    uses: "google/osv-scanner-action/.github/workflows/osv-scanner-reusable.yml@8deb546fdb875b9996d27d4950be7312dac076a1" # v2.5.0
+    uses: "google/osv-scanner-action/.github/workflows/osv-scanner-reusable.yml@a345acffa64b0eaede81a3d9aae6141214d9c8fc" # v2.6.0
     with:
       # Example of specifying custom arguments
       scan-args: |-
@@ -40,7 +40,7 @@ jobs:
         ./
   scan-pr:
     if: ${{ github.event_name == 'pull_request' || github.event_name == 'merge_group' }}
-    uses: "google/osv-scanner-action/.github/workflows/osv-scanner-reusable-pr.yml@8deb546fdb875b9996d27d4950be7312dac076a1" # v2.5.0
+    uses: "google/osv-scanner-action/.github/workflows/osv-scanner-reusable-pr.yml@a345acffa64b0eaede81a3d9aae6141214d9c8fc" # v2.6.0
     with:
       # Example of specifying custom arguments
       scan-args: |-

.github/workflows/rust-clippy.yml

@@ -29,7 +29,7 @@ jobs:
           persist-credentials: false
 
       - name: Install Rust toolchain
-        uses: actions-rust-lang/setup-rust-toolchain@166cdcfd11aee3cb47222f9ddb555ce30ddb9659 # v1
+        uses: actions-rust-lang/setup-rust-toolchain@ecabd13d1c56bd1345c230e542e9144811ad706f # v2
         with:
           components: clippy
           cache-key: clippy-sarif
@@ -60,7 +60,7 @@ jobs:
           exit 0
 
       - name: Upload Clippy SARIF
-        uses: github/codeql-action/upload-sarif@ff2f1c621b7f889edc0d3c761ac2e6a3f8cdb0dd # v4
+        uses: github/codeql-action/upload-sarif@2892aa5e19bbd11bc0cff5427e3b750a04d9e3c2 # v4
         if: always()
         with:
           sarif_file: rust-clippy-results.sarif

.github/workflows/semver.yml

@@ -1,31 +0,0 @@
-name: Semver
-
-on:
-  workflow_dispatch:
-  push:
-    tags:
-      - "irtt-proto/v*.*.*"
-      - "irtt-client/v*.*.*"
-      - "irtt-server/v*.*.*"
-      - "irtt-stats/v*.*.*"
-      - "irtt-rs/v*.*.*"
-
-permissions:
-  contents: read
-
-jobs:
-  semver:
-    name: cargo-semver-checks
-    runs-on: ubuntu-latest
-    timeout-minutes: 20
-
-    steps:
-      - name: Checkout
-        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
-        with:
-          persist-credentials: false
-
-      - name: Check semver compatibility
-        uses: obi1kenobi/cargo-semver-checks-action@6b69fcf40e9b5fb17adeb57e4b6ecd020649a239 # v2
-        with:
-          feature-group: all-features

.github/workflows/supply-chain.yml

@@ -1,79 +0,0 @@
-name: Supply chain
-
-on:
-  push:
-    branches:
-      - main
-  pull_request:
-    branches:
-      - main
-  merge_group:
-  schedule:
-    - cron: "41 2 * * 1"
-  workflow_dispatch:
-
-permissions:
-  contents: read
-
-jobs:
-  cargo-deny:
-    name: cargo-deny ${{ matrix.checks }}
-    runs-on: ubuntu-latest
-    timeout-minutes: 15
-
-    strategy:
-      fail-fast: false
-      matrix:
-        include:
-          # Advisories can appear after code was merged. Keep this visible,
-          # but don't let a surprise upstream advisory nuke every unrelated PR.
-          - checks: advisories
-            continue-on-error: true
-
-          # These are policy choices in this repo. They should block PRs.
-          - checks: bans licenses sources
-            continue-on-error: false
-
-    continue-on-error: ${{ matrix.continue-on-error }}
-
-    steps:
-      - name: Checkout
-        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
-        with:
-          persist-credentials: false
-
-      - name: Run cargo-deny
-        uses: EmbarkStudios/cargo-deny-action@3c6349835b2b7b196a839186cb8b78e02f7b5f25 # v2
-        with:
-          command: check
-          arguments: --all-features
-          command-arguments: ${{ matrix.checks }}
-
-  actionlint:
-    name: actionlint
-    runs-on: ubuntu-latest
-    timeout-minutes: 10
-
-    steps:
-      - name: Checkout
-        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
-        with:
-          persist-credentials: false
-
-      - name: actionlint handwritten workflows
-        uses: raven-actions/actionlint@205b530c5d9fa8f44ae9ed59f341a0db994aa6f8
-        with:
-          files: >-
-            .github/workflows/actions-security.yml,
-            .github/workflows/ci.yml,
-            .github/workflows/interop-netem.yml,
-            .github/workflows/osv-scanner.yml,
-            .github/workflows/rust-clippy.yml,
-            .github/workflows/semver.yml,
-            .github/workflows/supply-chain.yml
-
-      - name: actionlint generated release workflow
-        uses: raven-actions/actionlint@205b530c5d9fa8f44ae9ed59f341a0db994aa6f8
-        with:
-          files: .github/workflows/irtt-rs-release.yml
-          shellcheck: false

AGENTS.md

@@ -96,6 +96,11 @@ Prefer production interfaces and component/integration tests at the lowest archi
 
 Do not move library behavior into application-binary tests merely to make it more end-to-end. For example, pacing and multi-target scheduling belong in `irtt-client` even though the CLI exposes them.
 
+Concurrency correctness is a production requirement, but deterministic coverage
+does not by itself justify a test-only synchronization hook. Prefer simplifying
+the concurrency machinery or observing receipts/status/events through the public
+control surface before introducing or restoring internal race gates.
+
 ### Every persistent test must earn its place
 
 Before adding or retaining a test, be able to state the durable behavior, compatibility guarantee, regression, or invariant it protects. Other agents and humans will review tests on that basis. Do not add persistent tests merely because code changed, a branch exists, coverage would increase, or the test was useful during implementation.
@@ -173,6 +178,7 @@ Use the narrowest useful checks first. For substantive workspace changes, final
 cargo fmt --all -- --check
 cargo check --workspace --all-targets --all-features --locked
 cargo test --workspace --all-targets --all-features --locked
+cargo test --workspace --doc --all-features --locked
 cargo clippy --workspace --all-targets --all-features --locked -- -D warnings
 ```
 

CHANGELOG.md

@@ -10,6 +10,12 @@ release. The format is loosely based on
 
 ## irtt-proto
 
+### 0.5.1
+
+#### Added
+
+- Added a crate-specific README and runnable API doctests to make the published crate's protocol types and codecs easier to discover and use.
+
 ### 0.5.0
 
 #### Added
@@ -28,6 +34,24 @@ release. The format is loosely based on
 
 ## irtt-client
 
+### 0.5.3
+
+#### Added
+
+- `SocketConfig` can bind UDP sockets to a network interface and set a packet mark on Linux, Android, and Fuchsia, or select a routing FIB on FreeBSD.
+
+### 0.5.2
+
+#### Fixed
+
+- Kernel transmit-timestamp correlation is now invalidated when a probe send fails, preventing a later timestamp from being matched to the wrong probe.
+
+### 0.5.1
+
+#### Added
+
+- `ManagedCommandReceipt::blocking_wait()` lets synchronous callers wait for a managed target-set update to be applied or rejected without entering an async runtime.
+
 ### 0.5.0
 
 #### Added
@@ -50,6 +74,18 @@ release. The format is loosely based on
 
 ## irtt-server
 
+### 0.5.3
+
+#### Added
+
+- Added a crate-specific README and usage examples for single- and multi-listener servers, plus runnable API doctests.
+
+### 0.5.2
+
+#### Changed
+
+- `parse_hex_pattern`'s chunking now uses the stable `slice::as_chunks` API instead of `chunks_exact`; no behavior change.
+
 ### 0.5.1
 
 #### Added
@@ -83,6 +119,12 @@ release. The format is loosely based on
 
 ## irtt-stats
 
+### 0.5.1
+
+#### Added
+
+- Added a crate-specific README, a finite-versus-continuous statistics example, and runnable API doctests for the published crate.
+
 ### 0.5.0
 
 #### Fixed
@@ -96,6 +138,34 @@ release. The format is loosely based on
 
 ## irtt-rs
 
+### 0.7.1
+
+#### Fixed
+
+- `IRTT_SERVER_NO_DSCP` now accepts ordinary boolean environment values such as `1` and `0`; falsey values leave DSCP marking enabled, while truthy values disable it. The `--no-dscp` command-line flag remains a flag without a value.
+
+### 0.7.0
+
+#### Added
+
+- Client target arguments now support per-target HMAC configuration: append `@hmac=KEY` to override the global `--hmac` value for that target, or use `@hmac=` to explicitly disable HMAC for it. The target syntax supports context-aware escaping for literal delimiters.
+- Continuous client runs can now take complete desired target sets from standard input with `--targets-stdin`. Each non-empty record atomically replaces the current set, `[]` selects an empty set, and EOF requests a graceful stop. The controller retains only the newest unapplied record under transient replacement backpressure, with explicit bounds on record size, desired targets, and live target generations.
+
+#### Changed
+
+- A peer-initiated close is now target-local in stdin-controlled continuous runs: the controller and other desired targets keep running, and a later desired set can start that target again.
+
+### 0.6.2
+
+#### Added
+
+- Every `irtt-server` applet flag can now also be set via an `IRTT_SERVER_*` environment variable (`IRTT_SERVER_BIND`, `IRTT_SERVER_HMAC`, `IRTT_SERVER_MAX_SESSIONS`, `IRTT_SERVER_MAX_PACKET_LENGTH`, `IRTT_SERVER_MIN_INTERVAL`, `IRTT_SERVER_BURST`, `IRTT_SERVER_IDLE_TIMEOUT`, `IRTT_SERVER_MAX_DURATION`, `IRTT_SERVER_TIMESTAMP_ALLOWANCE`, `IRTT_SERVER_NO_DSCP`), for deployments that configure by environment (containers, orchestrators) instead of command-line flags. An explicit flag on the command line still overrides the corresponding variable.
+- A `Dockerfile` and Gitea Actions workflow publishing a minimal, statically linked `irtt-server` container image (cross-compiled for `amd64`/`arm64` via `tonistiigi/xx`, no QEMU) to this project's Gitea and GHCR container registries.
+
+#### Changed
+
+- The bundled `ctrlc` dependency now enables its `termination` feature, so the applet also handles `SIGTERM` (not just `SIGINT`) for graceful shutdown.
+
 ### 0.6.1
 
 #### Added

Cargo.lock

@@ -141,9 +141,9 @@ checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
 
 [[package]]
 name = "bitflags"
-version = "2.13.1"
+version = "2.13.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b588b76d00fde79687d7646a9b5bdf3cc0f655e0bbd080335a95d7e96f3587da"
+checksum = "3ded4057c258ba199e2d26386d3af3780957ecaee6c4ef4041c6b4b8b97c0b06"
 
 [[package]]
 name = "block-buffer"
@@ -201,9 +201,9 @@ dependencies = [
 
 [[package]]
 name = "cfg-if"
-version = "1.0.4"
+version = "1.0.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
+checksum = "4e7648175b45a9a48536d676f68d918270699102aa8dab5496df06904c914600"
 
 [[package]]
 name = "cfg_aliases"
@@ -213,9 +213,9 @@ checksum = "f079e83a288787bcd14a6aea84cee5c87a67c5a3e660c30f557a3d24761b3527"
 
 [[package]]
 name = "clap"
-version = "4.6.6"
+version = "4.6.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "473c7e07f409a8d772161724aa8db6a765a2532a70f9667eeb7b49d3d02fbdca"
+checksum = "aa8876b300ab35ba921adea3dfd70157a46249b33f95c9084ae5709785478946"
 dependencies = [
  "clap_builder",
  "clap_derive",
@@ -223,9 +223,9 @@ dependencies = [
 
 [[package]]
 name = "clap_builder"
-version = "4.6.6"
+version = "4.6.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7b48fea5a88e9ae728a2dcbedbfc0e730f7d60da42e1cb049a83c9fb8b789889"
+checksum = "ec0797fb7aeb1406c84efac526901f7ec3ead2124f946b494e72879d4b54704d"
 dependencies = [
  "anstream",
  "anstyle",
@@ -235,21 +235,21 @@ dependencies = [
 
 [[package]]
 name = "clap_derive"
-version = "4.6.4"
+version = "4.6.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d012d2b9d65aca7f18f4d9878a045bc17899bba951561ba5ec3c2ba1eed9a061"
+checksum = "f9c751b79415d4e559e3d1fcf128e09e720eb673a06d26cf6f392d37d75b66e0"
 dependencies = [
  "heck",
  "proc-macro2",
  "quote",
- "syn 3.0.3",
+ "syn 3.0.6",
 ]
 
 [[package]]
 name = "clap_lex"
-version = "1.1.0"
+version = "1.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c8d4a3bb8b1e0c1050499d1815f5ab16d04f0959b233085fb31653fbfc9d98f9"
+checksum = "1c133bc6a41be0d194c306b5506d15e6feeea7b1d6604bd3f8310dfb2ca96486"
 
 [[package]]
 name = "cmov"
@@ -313,7 +313,7 @@ version = "0.29.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d8b9f2e4c67f833b660cdb0a3523065869fb35570177239812ed4c905aeff87b"
 dependencies = [
- "bitflags 2.13.1",
+ "bitflags 2.13.2",
  "crossterm_winapi",
  "derive_more",
  "document-features",
@@ -385,9 +385,9 @@ dependencies = [
 
 [[package]]
 name = "darling"
-version = "0.24.0"
+version = "0.24.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "88490bf1b990d87eaaa7ac8aa887f629a08e7359765b4911faf63c3763347d23"
+checksum = "ed17f5901b6630b993ca003def43f2f8ef4014fc13b047b57aad617ff32bc2ec"
 dependencies = [
  "darling_core",
  "darling_macro",
@@ -395,26 +395,26 @@ dependencies = [
 
 [[package]]
 name = "darling_core"
-version = "0.24.0"
+version = "0.24.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "084e274f91c482280130e1e34e0b8d6e66776a060d7b6de7b84289ca778868c4"
+checksum = "6837e2cf7485aaae18f86181d2f0e9a7ed297a025e220aeabf63fdebd3a2ddff"
 dependencies = [
  "ident_case",
  "proc-macro2",
  "quote",
  "strsim",
- "syn 3.0.3",
+ "syn 3.0.6",
 ]
 
 [[package]]
 name = "darling_macro"
-version = "0.24.0"
+version = "0.24.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "68f5792fa0d41cd2325ce0ffa64f0a340eaebd4971a3a0c5e1ffd2cc488a355e"
+checksum = "2ac7135c3ef02b2f7833bbeb1be5ba7f966dcde8a87c6b87f65a778d71a02785"
 dependencies = [
  "darling_core",
  "quote",
- "syn 3.0.3",
+ "syn 3.0.6",
 ]
 
 [[package]]
@@ -479,7 +479,7 @@ version = "0.3.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1e0e367e4e7da84520dedcac1901e4da967309406d1e51017ae1abfb97adbd38"
 dependencies = [
- "bitflags 2.13.1",
+ "bitflags 2.13.2",
  "block2",
  "libc",
  "objc2",
@@ -496,9 +496,9 @@ dependencies = [
 
 [[package]]
 name = "either"
-version = "1.17.0"
+version = "1.18.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9e5e8f6c15a24b9a3ee5efec809ccd006d3b30e8b3bb63c39af737c7f87daa1d"
+checksum = "252afb9ae5eaa683babdc6a068b3f5726eb19e05070c731f9b2a23a7c3e8ed34"
 
 [[package]]
 name = "equivalent"
@@ -554,9 +554,9 @@ dependencies = [
 
 [[package]]
 name = "finl_unicode"
-version = "1.4.0"
+version = "1.5.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9844ddc3a6e533d62bba727eb6c28b5d360921d5175e9ff0f1e621a5c590a4d5"
+checksum = "80bb028c8b4148c9ee0cca68fcd9add6044e81d3619f48577ddf13a263d047a2"
 
 [[package]]
 name = "fixedbitset"
@@ -678,9 +678,9 @@ dependencies = [
 
 [[package]]
 name = "hybrid-array"
-version = "0.4.14"
+version = "0.4.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "707114b52a152fa7bdb290cd7cd5912d9467273b6d74e21b8d81aca1f8533f6b"
+checksum = "27f864f10dfb56725ce5ce5472bc52252c8f93a4ab86327122cebf62c5f59a17"
 dependencies = [
  "typenum",
 ]
@@ -702,27 +702,26 @@ dependencies = [
 
 [[package]]
 name = "instability"
-version = "0.3.13"
+version = "0.3.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2bf84e73fa6f27f299dec58e13223cf70db80da872eb921d4f6138342a0eabc8"
+checksum = "4c3b5acc1e2fd9375041a388da33d1eb8aed5f7a8c0dd3543e3ea2805adfbe20"
 dependencies = [
  "darling",
  "indoc",
  "proc-macro2",
  "quote",
- "syn 3.0.3",
+ "syn 3.0.6",
 ]
 
 [[package]]
 name = "irtt-client"
-version = "0.5.0"
+version = "0.5.3"
 dependencies = [
  "irtt-proto",
  "irtt-server",
  "nix 0.31.3",
- "proptest",
  "socket2",
- "thiserror 2.0.20",
+ "thiserror 2.0.21",
  "tokio",
 ]
 
@@ -738,18 +737,18 @@ dependencies = [
 
 [[package]]
 name = "irtt-proto"
-version = "0.5.0"
+version = "0.5.1"
 dependencies = [
  "hmac",
  "md-5",
  "proptest",
  "subtle",
- "thiserror 2.0.20",
+ "thiserror 2.0.21",
 ]
 
 [[package]]
 name = "irtt-rs"
-version = "0.6.1"
+version = "0.7.1"
 dependencies = [
  "clap",
  "crossterm",
@@ -764,21 +763,22 @@ dependencies = [
 
 [[package]]
 name = "irtt-server"
-version = "0.5.1"
+version = "0.5.3"
 dependencies = [
  "getrandom 0.4.3",
  "irtt-proto",
  "nix 0.31.3",
  "socket2",
- "thiserror 2.0.20",
+ "thiserror 2.0.21",
  "tokio",
 ]
 
 [[package]]
 name = "irtt-stats"
-version = "0.5.0"
+version = "0.5.1"
 dependencies = [
  "irtt-client",
+ "measurement-stats",
  "proptest",
 ]
 
@@ -805,9 +805,9 @@ checksum = "8f42a60cbdf9a97f5d2305f08a87dc4e09308d1276d28c869c684d7777685682"
 
 [[package]]
 name = "js-sys"
-version = "0.3.104"
+version = "0.3.106"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0e0c1080212aad755ea003d18543e8768dd432c48819efd73a7bf1e39b7a5a3a"
+checksum = "7883d941dae510fb2d978fc3fe018c71c9e2892fd38854de3e8b92c2e5ad9cc5"
 dependencies = [
  "cfg-if",
  "futures-util",
@@ -822,7 +822,7 @@ checksum = "bde5057d6143cc94e861d90f591b9303d6716c6b9602309150bd068853c10899"
 dependencies = [
  "hashbrown 0.16.1",
  "portable-atomic",
- "thiserror 2.0.20",
+ "thiserror 2.0.21",
 ]
 
 [[package]]
@@ -855,7 +855,7 @@ version = "0.3.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e752191d037c44ad111a8caa762921926658402f01cc1253f7bef2020ece4f5e"
 dependencies = [
- "bitflags 2.13.1",
+ "bitflags 2.13.2",
 ]
 
 [[package]]
@@ -881,15 +881,15 @@ dependencies = [
 
 [[package]]
 name = "log"
-version = "0.4.33"
+version = "0.4.34"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0ceec5bc11778974d1bcb055b18002eba7f4b3518b6a0081b3af5f21666da9ad"
+checksum = "f9f8bd3e56ce4dfc153cf470fffbfa98c7620958b312ca5c3a4b8d5181fd13c6"
 
 [[package]]
 name = "lru"
-version = "0.18.2"
+version = "0.18.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5d2f2f9b4ba7e6b24d95e7e899329d35be83bcded72c8540cdd5368932d1d90a"
+checksum = "ef9ac18847474e638e3702b76c65d4eb93428471a74778ef0f1be711717f89b5"
 dependencies = [
  "hashbrown 0.17.1",
 ]
@@ -914,6 +914,12 @@ dependencies = [
  "digest 0.11.3",
 ]
 
+[[package]]
+name = "measurement-stats"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "0edbfa45a060f44b15568637075ecebbe258c22f86ce6f2b5d58d7a64cbdb689"
+
 [[package]]
 name = "memchr"
 version = "2.8.3"
@@ -943,9 +949,9 @@ checksum = "68354c5c6bd36d73ff3feceb05efa59b6acb7626617f4962be322a825e61f79a"
 
 [[package]]
 name = "mio"
-version = "1.2.2"
+version = "1.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "30d65c71f1ce40ab09135ce117d742b9f8a19ff91a41a8b57ed50bc2de59c427"
+checksum = "4b18443e9c262bfe8fa82f51666e2642c53393f7e5c27b3e1aeab922cff5b9d8"
 dependencies = [
  "libc",
  "log",
@@ -959,7 +965,7 @@ version = "0.29.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "71e2746dc3a24dd78b3cfcb7be93368c6de9963d30f43a6a73998a9cf4b17b46"
 dependencies = [
- "bitflags 2.13.1",
+ "bitflags 2.13.2",
  "cfg-if",
  "cfg_aliases",
  "libc",
@@ -972,7 +978,7 @@ version = "0.31.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cf20d2fde8ff38632c426f1165ed7436270b44f199fc55284c38276f9db47c3d"
 dependencies = [
- "bitflags 2.13.1",
+ "bitflags 2.13.2",
  "cfg-if",
  "cfg_aliases",
  "libc",
@@ -1118,9 +1124,9 @@ dependencies = [
 
 [[package]]
 name = "pest"
-version = "2.9.0"
+version = "2.9.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5a07a60cc7a4d00c91f95c685609d1d2f79050e6804b70ebedd7650f0b839bcf"
+checksum = "45d3aca230fad2e6f6317ca0a72724338c4960cb97168a85cdee66df4a9a21a8"
 dependencies = [
  "memchr",
  "ucd-trie",
@@ -1128,9 +1134,9 @@ dependencies = [
 
 [[package]]
 name = "pest_derive"
-version = "2.9.0"
+version = "2.9.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b3a83744a5c8455b8b3e0dc5031362780a347c878bdd11584d1a8984228cc88d"
+checksum = "284b60557f2c4a2e72ad3f2d34d42685a2fa4a6a61d0d2a10c0ae2a5e916c2cf"
 dependencies = [
  "pest",
  "pest_generator",
@@ -1138,9 +1144,9 @@ dependencies = [
 
 [[package]]
 name = "pest_generator"
-version = "2.9.0"
+version = "2.9.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e0cd3451aa3de60d4b9a1e736885e4dea6b31617598026f12256ad566d63304a"
+checksum = "1d9d1f08a115309ee99268cf85e5228e0e56aa9caf8841ec12866b6be07c3109"
 dependencies = [
  "pest",
  "pest_meta",
@@ -1151,9 +1157,9 @@ dependencies = [
 
 [[package]]
 name = "pest_meta"
-version = "2.9.0"
+version = "2.9.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e04d3a0849e241d7dfce834c83b1c5edc8622009e8dd51a12ba1927c32f05496"
+checksum = "ed93ba1a9ffcca32130a5188701c81c0c49cf00d4b7c5007d5148951d743adcb"
 dependencies = [
  "pest",
 ]
@@ -1185,7 +1191,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3c80231409c20246a13fddb31776fb942c38553c51e871f8cbd687a4cfb5843d"
 dependencies = [
  "phf_shared",
- "rand 0.8.7",
+ "rand 0.8.8",
 ]
 
 [[package]]
@@ -1254,7 +1260,7 @@ checksum = "4b45fcc2344c680f5025fe57779faef368840d0bd1f42f216291f0dc4ace4744"
 dependencies = [
  "bit-set 0.8.0",
  "bit-vec 0.8.0",
- "bitflags 2.13.1",
+ "bitflags 2.13.2",
  "num-traits",
  "rand 0.9.5",
  "rand_chacha",
@@ -1294,9 +1300,9 @@ checksum = "f8dcc9c7d52a811697d2151c701e0d08956f92b0e24136cf4cf27b57a6a0d9bf"
 
 [[package]]
 name = "rand"
-version = "0.8.7"
+version = "0.8.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "22f6172bdec972074665ed81ed53b71da00bfc44b65a753cfde883ec4c702a1a"
+checksum = "e058c7de0b26af77780c769414d6257830bb240f3c38477dbc2c16e5f54d6d4c"
 dependencies = [
  "rand_core 0.6.4",
 ]
@@ -1367,7 +1373,7 @@ version = "0.1.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cbb175c433c8e28a809d1f5773a2ae96e68c0ce40db865cbab1020bf33ae479c"
 dependencies = [
- "bitflags 2.13.1",
+ "bitflags 2.13.2",
  "compact_str",
  "critical-section",
  "hashbrown 0.17.1",
@@ -1377,7 +1383,7 @@ dependencies = [
  "palette",
  "serde",
  "strum",
- "thiserror 2.0.20",
+ "thiserror 2.0.21",
  "unicode-segmentation",
  "unicode-truncate",
  "unicode-width",
@@ -1432,7 +1438,7 @@ version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "66e3d19bcc9130ca376277d93b60767ff121ace3be06f5f95f81dd68956407d1"
 dependencies = [
- "bitflags 2.13.1",
+ "bitflags 2.13.2",
  "hashbrown 0.17.1",
  "indoc",
  "instability",
@@ -1452,7 +1458,7 @@ version = "0.5.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ed2bf2547551a7053d6fdfafda3f938979645c44812fbfcda098faae3f1a362d"
 dependencies = [
- "bitflags 2.13.1",
+ "bitflags 2.13.2",
 ]
 
 [[package]]
@@ -1495,11 +1501,11 @@ dependencies = [
 
 [[package]]
 name = "rustix"
-version = "1.1.4"
+version = "1.1.5"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b6fe4565b9518b83ef4f91bb47ce29620ca828bd32cb7e408f0062e9930ba190"
+checksum = "891efababe418670775f199f0d233d84843c227a0949a883ce15b37c78d6629d"
 dependencies = [
- "bitflags 2.13.1",
+ "bitflags 2.13.2",
  "errno",
  "libc",
  "linux-raw-sys",
@@ -1569,7 +1575,7 @@ checksum = "e7a5d71263a5a7d47b41f6b3f06ba276f10cc18b0931f1799f710578e2309348"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 3.0.3",
+ "syn 3.0.6",
 ]
 
 [[package]]
@@ -1616,9 +1622,9 @@ dependencies = [
 
 [[package]]
 name = "siphasher"
-version = "1.0.3"
+version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8ee5873ec9cce0195efcb7a4e9507a04cd49aec9c83d0389df45b1ef7ba2e649"
+checksum = "33f4fe9184a62d842c9ef383018f3306d8ba224fd9d836f56d7288308847c256"
 
 [[package]]
 name = "slab"
@@ -1628,9 +1634,9 @@ checksum = "0c790de23124f9ab44544d7ac05d60440adc586479ce501c1d6d7da3cd8c9cf5"
 
 [[package]]
 name = "smallvec"
-version = "1.15.2"
+version = "1.16.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "8ed6a63f02c8539c91a8685a86f4099661ba3da017932f6ebbea6de3f0fa7c90"
+checksum = "f9395f0f0eee849a9b707b2f06bb92a6a422090e2123bb2ef8e87a0e61892a8e"
 
 [[package]]
 name = "socket2"
@@ -1705,9 +1711,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "3.0.3"
+version = "3.0.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "53e9bae58849f64dfa4f5d5ae372c8341f7305f82a3868709269343628b659a3"
+checksum = "8593e8e72159ed2257d083c7a454a85cbf854f37a0966d8d483aff8c8a3ebcee"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1733,7 +1739,7 @@ version = "0.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9048a889effe34a5cddee0af7f53285198b16dca3be510858d38dfdb3e62a04e"
 dependencies = [
- "bitflags 2.13.1",
+ "bitflags 2.13.2",
  "parking_lot",
  "rustix",
  "signal-hook",
@@ -1769,7 +1775,7 @@ checksum = "4676b37242ccbd1aabf56edb093a4827dc49086c0ffd764a5705899e0f35f8f7"
 dependencies = [
  "anyhow",
  "base64",
- "bitflags 2.13.1",
+ "bitflags 2.13.2",
  "fancy-regex",
  "filedescriptor",
  "finl_unicode",
@@ -1814,11 +1820,11 @@ dependencies = [
 
 [[package]]
 name = "thiserror"
-version = "2.0.20"
+version = "2.0.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ec86235f5fcc2a73650310756d2ac5b138a5780bbbdfae3eeccec992c435ba4f"
+checksum = "09e52cb86a36cede5cb101bf8908837b3e4c6e5e59fe7fd85c23fb56200d189e"
 dependencies = [
- "thiserror-impl 2.0.20",
+ "thiserror-impl 2.0.21",
 ]
 
 [[package]]
@@ -1834,13 +1840,13 @@ dependencies = [
 
 [[package]]
 name = "thiserror-impl"
-version = "2.0.20"
+version = "2.0.21"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bc04cd3e1236dd4a98afca4569f2deb3f120e5422a4023be2cb683f8486292af"
+checksum = "fe5197923287db20a58125f0bc85c062f7f2c892de97b18c356f9efb14b28524"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 3.0.3",
+ "syn 3.0.6",
 ]
 
 [[package]]
@@ -1886,7 +1892,7 @@ checksum = "78773a2a397f451582ce068015985c33193cf6dea8b74d2a639fe457b2f07b0e"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 3.0.3",
+ "syn 3.0.6",
 ]
 
 [[package]]
@@ -1909,9 +1915,9 @@ checksum = "eaea85b334db583fe3274d12b4cd1880032beab409c0d774be044d4480ab9a94"
 
 [[package]]
 name = "unicode-ident"
-version = "1.0.24"
+version = "1.0.26"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e6e4313cd5fcd3dad5cafa179702e2b244f760991f45397d14d4ebf38247da75"
+checksum = "d245f478577f809a851594d02313b640fb437e0bb33866753cff937863096954"
 
 [[package]]
 name = "unicode-segmentation"
@@ -1944,9 +1950,9 @@ checksum = "06abde3611657adf66d383f00b093d7faecc7fa57071cce2578660c9f1010821"
 
 [[package]]
 name = "uuid"
-version = "1.24.1"
+version = "1.26.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2cefc03fd367c0c6d4305de1b312cf00248c4114f4a0418ce6a6af769e3b0bd9"
+checksum = "2ef6dac1e96601b4fb3acccccff2139741fcb757cb9a36089bf5be91cfb285ce"
 dependencies = [
  "atomic",
  "getrandom 0.4.3",
@@ -1995,9 +2001,9 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen"
-version = "0.2.127"
+version = "0.2.129"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1b70935747edd64d89de3efa29d73789b806c15798f8e7dca4d8ac356b50ce70"
+checksum = "9bb54f33acc68fd454578d9820b0bde1a1a3d17aa17bb7b6595806d02886d409"
 dependencies = [
  "cfg-if",
  "once_cell",
@@ -2008,9 +2014,9 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen-macro"
-version = "0.2.127"
+version = "0.2.129"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "77775f8f3f7217702089053b94958f8f54061a3f663417df76e19cbdcca29bc1"
+checksum = "2e29d0c35b16e224a7eeb5cd2d25e3e1968fbd65604117b44d3b789d00ee8535"
 dependencies = [
  "quote",
  "wasm-bindgen-macro-support",
@@ -2018,22 +2024,22 @@ dependencies = [
 
 [[package]]
 name = "wasm-bindgen-macro-support"
-version = "0.2.127"
+version = "0.2.129"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e11d33f857dc2fb11b8bc75aee111aa9cbeb12cd9f25efd3d4c2a3dd4e235284"
+checksum = "6f501a8bc3719dba86ef8ae4728879c08001bea749eb1333ac5b91e040e2a6b7"
 dependencies = [
  "bumpalo",
  "proc-macro2",
  "quote",
- "syn 2.0.119",
+ "syn 3.0.6",
  "wasm-bindgen-shared",
 ]
 
 [[package]]
 name = "wasm-bindgen-shared"
-version = "0.2.127"
+version = "0.2.129"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7ef64dbcc55df09c7e5a46182d181c2cfa3e925f3da937ea764728b4bbb9dcbf"
+checksum = "23f0c9c52aa7cd7d77769a4cfe2a9adb1b331f489a41d912ce14513d5ab995c6"
 dependencies = [
  "unicode-ident",
 ]
@@ -2155,18 +2161,18 @@ checksum = "1ebf944e87a7c253233ad6766e082e3cd714b5d03812acc24c318f549614536e"
 
 [[package]]
 name = "zerocopy"
-version = "0.8.56"
+version = "0.8.59"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "556764e583adb45a9f8d413c2a147fa7e8d821e48e12b14fd560b607998b75eb"
+checksum = "6df92bf3d9227be3d53173901ddbffac2babc27ae50f397776ffd6dc33f800cb"
 dependencies = [
  "zerocopy-derive",
 ]
 
 [[package]]
 name = "zerocopy-derive"
-version = "0.8.56"
+version = "0.8.59"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f2ab42fc20575779bd240faa45f94a74256f755c0fa9e89f0ede20d91d0cdfc1"
+checksum = "ac4f328cf2f05d084e496c3e9c3f33ed0a183656a16e1fcec4d464d8373aec82"
 dependencies = [
  "proc-macro2",
  "quote",

Cargo.toml

@@ -18,8 +18,8 @@ homepage = "https://github.com/Lochnair/irtt-rs"
 
 [workspace.dependencies]
 irtt-proto = { version = "0.5.0", path = "crates/irtt-proto" }
-irtt-client = { version = "0.5.0", path = "crates/irtt-client" }
-irtt-server = { version = "0.5.1", path = "crates/irtt-server" }
+irtt-client = { version = "0.5.1", path = "crates/irtt-client" }
+irtt-server = { version = "0.5.2", path = "crates/irtt-server" }
 irtt-stats = { version = "0.5.0", path = "crates/irtt-stats" }
 
 [profile.release]

Dockerfile

@@ -0,0 +1,42 @@
+# syntax=docker/dockerfile:1
+
+# Builds the irtt-server applet only, statically linked against musl, and
+# ships it in a scratch image with no shell or libc.
+#
+# Cross-compiles for TARGETPLATFORM using tonistiigi/xx: the builder stage
+# always runs natively on BUILDPLATFORM (no QEMU emulation) and xx-cargo
+# picks the right musl target triple, sysroot, and linker for whatever
+# platform buildx asked for.
+
+FROM --platform=$BUILDPLATFORM tonistiigi/xx AS xx
+
+FROM --platform=$BUILDPLATFORM rust:1.98-alpine AS builder
+
+COPY --from=xx / /
+
+RUN apk add --no-cache clang lld file
+
+ARG TARGETPLATFORM
+RUN xx-apk add --no-cache musl-dev
+
+WORKDIR /build
+
+COPY Cargo.toml Cargo.lock ./
+COPY crates ./crates
+
+RUN xx-cargo build \
+    --release \
+    --locked \
+    -p irtt-rs \
+    --bin irtt-server \
+    --no-default-features \
+    --features server \
+    --target-dir /build/target \
+    && xx-verify /build/target/$(xx-cargo --print-target-triple)/release/irtt-server \
+    && cp /build/target/$(xx-cargo --print-target-triple)/release/irtt-server /irtt-server
+
+FROM scratch
+
+COPY --from=builder /irtt-server /irtt-server
+
+ENTRYPOINT ["/irtt-server"]

README.md

@@ -171,6 +171,7 @@ when to use it instead of `irtt-client`/`irtt-server` directly.
 ```sh
 cargo fmt --all -- --check
 cargo test --workspace --locked
+cargo test --workspace --doc --all-features --locked
 cargo clippy --workspace --all-targets --all-features --locked -- -D warnings
 ```
 

crates/irtt-app/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "irtt-rs"
-version = "0.6.1"
+version = "0.7.1"
 description = "IRTT-compatible client, TUI, and server applications"
 edition.workspace = true
 license.workspace = true
@@ -47,9 +47,9 @@ server = ["dep:irtt-server", "dep:tokio"]
 tui =["dep:irtt-client", "irtt-client/ancillary", "irtt-client/tokio", "dep:irtt-proto", "dep:irtt-stats", "dep:ratatui", "dep:crossterm"]
 
 [dependencies]
-clap = { version = "4.6.6", features = ["derive"] }
+clap = { version = "4.6.7", features = ["derive", "env"] }
 crossterm = { version = "0.29.0", optional = true }
-ctrlc = "3.5.2"
+ctrlc = { version = "3.5.2", features = ["termination"] }
 irtt-client = { workspace = true, optional = true }
 irtt-proto = { workspace = true, optional = true }
 irtt-server = { workspace = true, optional = true }

crates/irtt-app/src/applet.rs

@@ -22,7 +22,7 @@ pub fn detect_applet_from_argv0(argv0: &str) -> Option<RequestedApplet> {
     match applet_basename(argv0) {
         "irtt-client" => Some(RequestedApplet::Client),
         "irtt-tui" => Some(RequestedApplet::Tui),
-        "irttd" | "irtt-server" => Some(RequestedApplet::Server),
+        "irtt-server" => Some(RequestedApplet::Server),
         "irtt-rs" => None,
         _ => None,
     }
@@ -180,147 +180,3 @@ fn applet_argv(applet_name: &str, args: &[OsString]) -> Vec<OsString> {
     argv.extend(args.iter().cloned());
     argv
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn applet_detection_maps_binary_names() {
-        assert_eq!(
-            detect_applet_from_argv0("/usr/bin/irtt-client"),
-            Some(RequestedApplet::Client)
-        );
-        assert_eq!(
-            detect_applet_from_argv0("irtt-tui"),
-            Some(RequestedApplet::Tui)
-        );
-        assert_eq!(
-            detect_applet_from_argv0("irtt-server"),
-            Some(RequestedApplet::Server)
-        );
-        assert_eq!(detect_applet_from_argv0("irtt-rs"), None);
-        assert_eq!(detect_applet_from_argv0("custom-name"), None);
-    }
-
-    #[test]
-    fn old_irtt_cli_binary_name_is_no_longer_a_recognized_applet() {
-        assert_eq!(detect_applet_from_argv0("irtt-cli"), None);
-        assert_eq!(detect_applet_from_argv0("/usr/bin/irtt-cli"), None);
-    }
-
-    #[test]
-    fn applet_detection_ignores_the_platform_executable_suffix() {
-        let exe = std::env::consts::EXE_SUFFIX;
-
-        assert_eq!(
-            detect_applet_from_argv0(&format!("/opt/irtt/irtt-server{exe}")),
-            Some(RequestedApplet::Server)
-        );
-        assert_eq!(
-            detect_applet_from_argv0(&format!("irtt-client{exe}")),
-            Some(RequestedApplet::Client)
-        );
-
-        // The dispatcher's own name must not be taken for an unknown applet.
-        let dispatcher = format!("irtt-rs{exe}");
-        assert_eq!(detect_applet_from_argv0(&dispatcher), None);
-        assert!(dispatch_from_argv(vec![dispatcher.into(), "--help".into()]).is_ok());
-
-        // A name that merely ends in the suffix letters keeps them.
-        assert!(detect_applet_from_argv0("irtt-serverexe").is_none());
-    }
-
-    #[test]
-    fn windows_executable_suffix_handling_is_assertable_from_any_host() {
-        assert_eq!(
-            strip_suffix_ignoring_case("irtt-server.exe", ".exe"),
-            "irtt-server"
-        );
-        assert_eq!(strip_suffix_ignoring_case("IRTT-RS.EXE", ".exe"), "IRTT-RS");
-        assert_eq!(
-            strip_suffix_ignoring_case("irtt-server", ".exe"),
-            "irtt-server"
-        );
-        assert_eq!(
-            strip_suffix_ignoring_case("irtt-serverexe", ".exe"),
-            "irtt-serverexe"
-        );
-        assert_eq!(strip_suffix_ignoring_case(".exe", ".exe"), ".exe");
-        assert_eq!(
-            strip_suffix_ignoring_case("irtt-server.exe", ""),
-            "irtt-server.exe"
-        );
-        // A multi-byte tail must not split mid-character.
-        assert_eq!(strip_suffix_ignoring_case("irtt-så", ".exe"), "irtt-så");
-    }
-
-    #[test]
-    fn canonical_help_renders_dispatcher_help() {
-        let dispatch = dispatch_from_argv(vec!["irtt-rs".into(), "--help".into()]).unwrap();
-        let AppletDispatch::Help(help) = dispatch else {
-            panic!("expected dispatcher help");
-        };
-        assert!(help.contains("IRTT-compatible multi-applet dispatcher"));
-        assert!(help.contains("client"));
-        if cfg!(feature = "tui") {
-            assert!(help.contains("Run the terminal UI applet"));
-        } else {
-            assert!(help.contains("Terminal UI applet is not available in this build"));
-        }
-        assert!(help.contains("server"));
-        if cfg!(feature = "server") {
-            assert!(help.contains("Run the UDP server applet"));
-        } else {
-            assert!(help.contains("UDP server applet is not available in this build"));
-        }
-    }
-
-    #[test]
-    fn canonical_without_applet_is_an_error() {
-        let err = dispatch_from_argv(vec!["irtt-rs".into()]).unwrap_err();
-        assert!(err.contains("choose an applet"));
-        assert!(err.contains("client"));
-        if cfg!(feature = "tui") {
-            assert!(err.contains("tui"));
-        }
-        assert!(err.contains("server"));
-    }
-
-    #[test]
-    fn canonical_subcommands_dispatch_to_applet_argv() {
-        assert_eq!(
-            dispatch_from_argv(vec!["irtt-rs".into(), "client".into(), "host:2112".into()])
-                .unwrap(),
-            AppletDispatch::Run {
-                applet: RequestedApplet::Client,
-                argv: vec!["irtt-client".into(), "host:2112".into()],
-            }
-        );
-        assert_eq!(
-            dispatch_from_argv(vec!["irtt-rs".into(), "tui".into(), "host:2112".into()]).unwrap(),
-            AppletDispatch::Run {
-                applet: RequestedApplet::Tui,
-                argv: vec!["irtt-tui".into(), "host:2112".into()],
-            }
-        );
-        assert_eq!(
-            dispatch_from_argv(vec!["irtt-rs".into(), "server".into()]).unwrap(),
-            AppletDispatch::Run {
-                applet: RequestedApplet::Server,
-                argv: vec!["irtt-server".into()],
-            }
-        );
-    }
-
-    #[test]
-    fn unknown_irtt_binary_name_is_an_error() {
-        let err = dispatch_from_argv(vec!["/usr/bin/irtt-typo".into()]).unwrap_err();
-        assert!(err.contains("unknown applet name 'irtt-typo'"));
-        assert!(err.contains("irtt-client"));
-        if cfg!(feature = "tui") {
-            assert!(err.contains("irtt-tui"));
-        }
-        assert!(err.contains("irtt-server"));
-    }
-}

crates/irtt-app/src/cmd/client/args.rs

@@ -11,15 +11,22 @@ pub const DEFAULT_CLIENT_DURATION: Duration = Duration::from_secs(10);
 #[derive(Debug, Clone, Parser)]
 #[command(name = "irtt-client", about = "Minimal IRTT-compatible stream client")]
 pub struct ClientArgs {
-    /// Server address/host, optionally prefixed with LABEL=. Repeat for multi-target mode.
+    /// Server address/host, optionally prefixed with LABEL= and suffixed with @hmac=KEY. Repeat for multi-target mode.
     #[arg(
         value_name = "TARGET",
         num_args = 0..,
         value_parser = parse_target,
-        long_help = "Server address/host, optionally prefixed with LABEL=. Repeat for multi-target mode.\n\nExamples:\n  irtt-client host-a:2112 host-b:2112\n  irtt-client eu=host-a:2112 us=host-b:2112\n  irtt-client host-a:2112 eu=host-b:2112"
+        long_help = "Server address/host, optionally prefixed with LABEL= and suffixed with @hmac=KEY. Repeat for multi-target mode.\n\nExamples:\n  irtt-client host-a:2112 host-b:2112\n  irtt-client eu=host-a:2112 us=host-b:2112\n  irtt-client ams=host-a:2112@hmac=secret public=host-b:2112@hmac=\n\nA target without @hmac= inherits --hmac. @hmac= explicitly disables it for that target."
     )]
     pub targets: Vec<TargetArg>,
 
+    /// Read complete desired target sets from standard input in continuous mode.
+    #[arg(
+        long,
+        long_help = "Read one complete desired target set per stdin line in continuous mode. Commas separate targets and backslash escapes commas within a target. [] selects an empty desired set. Records are limited to 64 KiB. EOF stops the client gracefully and may discard a revision that has not yet been acknowledged as applied."
+    )]
+    pub targets_stdin: bool,
+
     /// Managed group pacing for multi-target mode.
     #[arg(
         long,
@@ -34,7 +41,7 @@ pub struct ClientArgs {
         default_value = "10s",
         value_parser = parse_test_duration,
         help = "Test duration; use 0 for continuous mode",
-        long_help = "Test duration; use 0 for continuous mode.\n\nFinite runs retain exact statistics for final summaries. Continuous mode uses bounded-memory running statistics and prints a final summary only when interrupted."
+        long_help = "Test duration; use 0 for continuous mode.\n\nFinite runs retain exact statistics for final summaries. Continuous mode uses bounded-memory running statistics and prints a final summary when interrupted; --targets-stdin also prints the final retained summary on EOF."
     )]
     pub duration: Duration,
 
@@ -86,12 +93,16 @@ impl ClientArgs {
     /// Targets are only required here. `--list-columns` returns before this is
     /// called, so listing columns still needs no target.
     pub fn prepare(&self) -> Result<ManagedRunSetup, String> {
+        if self.targets_stdin && !self.is_continuous() {
+            return Err("--targets-stdin requires --duration 0".to_owned());
+        }
         prepare_managed_run(
             &self.common,
             self.duration,
             TargetSelection {
                 targets: &self.targets,
                 pacing: self.pacing,
+                stdin_controlled: self.targets_stdin,
             },
         )
     }
@@ -140,180 +151,3 @@ pub enum HeaderMode {
     /// Never print headers.
     Never,
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use clap::{CommandFactory, Parser};
-    use irtt_client::NegotiationPolicy;
-    use irtt_proto::{Clock, ReceivedStats, StampAt};
-
-    fn parse(args: &[&str]) -> Result<ClientArgs, clap::Error> {
-        let mut argv = vec!["irtt-client"];
-        argv.extend_from_slice(args);
-        ClientArgs::try_parse_from(argv)
-    }
-
-    #[test]
-    fn client_parser_keeps_finite_default_duration() {
-        let args = parse(&["127.0.0.1:2112"]).unwrap();
-
-        assert_eq!(args.targets.len(), 1);
-        assert_eq!(args.targets[0].label, None);
-        assert_eq!(args.targets[0].addr, "127.0.0.1:2112");
-        assert_eq!(args.pacing, GroupPacingArg::Staggered);
-        assert_eq!(args.duration, DEFAULT_CLIENT_DURATION);
-        assert_eq!(args.interval, Duration::from_secs(1));
-        assert_eq!(args.format, OutputFormat::Table);
-        assert_eq!(args.columns, None);
-        assert_eq!(args.header, HeaderMode::Auto);
-        assert!(!args.is_continuous());
-        assert_eq!(args.timestamp_mode(), TimestampArg::Both);
-
-        let config = args.prepare().unwrap().client;
-        assert_eq!(config.duration, Some(DEFAULT_CLIENT_DURATION));
-        assert_eq!(config.received_stats, ReceivedStats::Both);
-        assert_eq!(config.stamp_at, StampAt::Both);
-        assert_eq!(config.clock, Clock::Both);
-        assert_eq!(config.negotiation_policy, NegotiationPolicy::Strict);
-    }
-
-    #[test]
-    fn client_parser_accepts_stream_formats_and_rejects_tui_output() {
-        for format in ["table", "csv", "tsv", "jsonl"] {
-            assert!(parse(&["--format", format, "127.0.0.1:2112"]).is_ok());
-        }
-        assert!(parse(&["--format", "tui", "127.0.0.1:2112"]).is_err());
-    }
-
-    #[test]
-    fn list_columns_does_not_require_server() {
-        let args = parse(&["--list-columns"]).unwrap();
-        assert!(args.targets.is_empty());
-        assert!(args.list_columns);
-        // The parser accepts no target; preparation is where a target becomes
-        // mandatory, and the stream command returns before preparing when
-        // listing columns.
-        let err = args.prepare().unwrap_err();
-        assert!(err.contains("--list-columns"));
-    }
-
-    #[test]
-    fn multiple_positional_targets_parse_as_targets() {
-        let args = parse(&["host-a:2112", "host-b:2112"]).unwrap();
-        let specs = args.prepare().unwrap().targets;
-
-        assert_eq!(specs[0].label, "host-a:2112");
-        assert_eq!(specs[0].managed.server_addr, "host-a:2112");
-        assert_eq!(specs[1].label, "host-b:2112");
-        assert_eq!(specs[1].managed.server_addr, "host-b:2112");
-    }
-
-    #[test]
-    fn repeated_labeled_targets_parse() {
-        let args = parse(&["ams=ams.example.com:2112", "sg=sg.example.com:2112"]).unwrap();
-        let specs = args.prepare().unwrap().targets;
-
-        assert_eq!(specs[0].label, "ams");
-        assert_eq!(specs[0].managed.server_addr, "ams.example.com:2112");
-        assert_eq!(specs[1].label, "sg");
-        assert_eq!(specs[1].managed.server_addr, "sg.example.com:2112");
-    }
-
-    #[test]
-    fn mixed_labeled_and_unlabeled_targets_preserve_argument_order() {
-        let args = parse(&["local.example", "eu=a.example", "backup.example"]).unwrap();
-        let specs = args.prepare().unwrap().targets;
-
-        let labels: Vec<_> = specs.iter().map(|target| target.label.as_str()).collect();
-        assert_eq!(labels, ["local.example", "eu", "backup.example"]);
-    }
-
-    #[test]
-    fn duplicate_labels_are_rejected() {
-        let args = parse(&["host-a:2112", "host-a:2112=host-b:2112"]).unwrap();
-        let err = args.prepare().unwrap_err();
-
-        assert!(err.contains("duplicate target label"));
-    }
-
-    #[test]
-    fn duplicate_positional_target_strings_get_stable_suffixes() {
-        let args = parse(&["host-a:2112", "host-a:2112"]).unwrap();
-        let specs = args.prepare().unwrap().targets;
-
-        assert_eq!(specs[0].label, "host-a:2112");
-        assert_eq!(specs[1].label, "host-a:2112#2");
-    }
-
-    #[test]
-    fn duplicate_target_endpoints_are_allowed() {
-        let args = parse(&["127.0.0.1:2112", "127.0.0.1"]).unwrap();
-        assert_eq!(args.prepare().unwrap().target_count(), 2);
-    }
-
-    #[test]
-    fn invalid_labelled_target_syntax_is_rejected() {
-        assert!(parse(&["=127.0.0.1:2112"]).is_err());
-        assert!(parse(&["label="]).is_err());
-    }
-
-    #[test]
-    fn old_target_option_is_rejected() {
-        assert!(parse(&["--target", "eu=host.example"]).is_err());
-    }
-
-    #[test]
-    fn pacing_option_accepts_supported_values() {
-        assert_eq!(
-            parse(&["--pacing", "staggered", "127.0.0.1:2112"])
-                .unwrap()
-                .pacing,
-            GroupPacingArg::Staggered
-        );
-        assert_eq!(
-            parse(&["--pacing", "burst", "127.0.0.1:2112"])
-                .unwrap()
-                .pacing,
-            GroupPacingArg::Burst
-        );
-    }
-
-    #[test]
-    fn client_help_lists_shared_protocol_options() {
-        let help = ClientArgs::command().render_help().to_string();
-        assert!(help.contains("--format <FORMAT>"));
-        assert!(!help.contains("--target "));
-        assert!(help.contains("--pacing <PACING>"));
-        assert!(help.contains("--columns <COLUMNS>"));
-        assert!(help.contains("--list-columns"));
-        assert!(help.contains("--header <HEADER>"));
-        assert!(help.contains("--tstamp <MODE>"));
-        assert!(help.contains("--stats <STATS>"));
-        assert!(help.contains("--sfill <STRING>"));
-        assert!(help.contains("--dscp <0..=63>"));
-        assert!(help.contains("--ttl <1..=255>"));
-        assert!(help.contains("--loose"));
-    }
-
-    #[test]
-    fn an_empty_hmac_key_is_rejected() {
-        let err = parse(&["--hmac", "", "127.0.0.1:2112"]).unwrap_err();
-        assert!(err.to_string().contains("HMAC key must not be empty"));
-    }
-
-    #[test]
-    fn a_non_empty_hmac_key_is_accepted() {
-        let args = parse(&["--hmac", "secret", "127.0.0.1:2112"]).unwrap();
-        let config = args.prepare().unwrap().client;
-        assert_eq!(config.hmac_key, Some(b"secret".to_vec()));
-    }
-
-    #[test]
-    fn output_format_summary_policy_is_table_only() {
-        assert!(OutputFormat::Table.prints_summary());
-        assert!(!OutputFormat::Csv.prints_summary());
-        assert!(!OutputFormat::Tsv.prints_summary());
-        assert!(!OutputFormat::Jsonl.prints_summary());
-    }
-}

crates/irtt-app/src/cmd/client/output.rs

@@ -207,7 +207,7 @@ enum OutputRow {
         client_send_wall: SystemTime,
         bytes: usize,
         send_call: Duration,
-        timer_error: Duration,
+        timer_error: Option<Duration>,
     },
     EchoReply(ReplyRow),
     Loss {
@@ -950,7 +950,7 @@ fn cell_for(row: &OutputRow, column: Column, context: RenderContext<'_>) -> Opti
         },
         Column::TimerErrorUs => match row {
             OutputRow::EchoSent { timer_error, .. } => {
-                Some(CellValue::Unsigned(duration_us(*timer_error)))
+                timer_error.map(|error| CellValue::Unsigned(duration_us(error)))
             }
             _ => None,
         },
@@ -1205,273 +1205,3 @@ fn write_json_string_content(out: &mut String, value: &str) {
         }
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use irtt_client::ClientTimestamp;
-    use std::{
-        net::{IpAddr, Ipv4Addr, SocketAddr},
-        time::Instant,
-    };
-
-    fn output_config(format: OutputFormat, columns: Option<&str>) -> OutputConfig {
-        OutputConfig::new(format, columns, HeaderMode::Auto, false).unwrap()
-    }
-
-    fn remote() -> SocketAddr {
-        SocketAddr::new(IpAddr::V4(Ipv4Addr::LOCALHOST), 2112)
-    }
-
-    fn reply() -> ClientEvent {
-        let sent_at = ClientTimestamp {
-            wall: UNIX_EPOCH + Duration::from_secs(1),
-            mono: Instant::now(),
-        };
-        let received_at = ClientTimestamp {
-            wall: sent_at.wall + Duration::from_micros(1200),
-            mono: sent_at.mono + Duration::from_micros(1200),
-        };
-        ClientEvent::EchoReply {
-            seq: 7,
-            remote: remote(),
-            sent_at,
-            received_at,
-            rtt: RttSample {
-                raw: Duration::from_micros(1200),
-                adjusted: None,
-                effective: SignedDuration::from_nanos(1_200_000),
-            },
-            server_timing: None,
-            one_way: None,
-            received_stats: None,
-            bytes: 64,
-            packet_meta: PacketMeta::default(),
-        }
-    }
-
-    #[test]
-    fn list_columns_includes_target() {
-        assert!(OutputConfig::list_columns().contains("target"));
-    }
-
-    #[test]
-    fn default_table_columns_always_include_target_first() {
-        let header = output_config(OutputFormat::Table, None)
-            .render_header()
-            .unwrap();
-
-        assert_eq!(header.split_whitespace().next(), Some("target"));
-    }
-
-    #[test]
-    fn default_structured_columns_always_include_target_first() {
-        for format in [OutputFormat::Csv, OutputFormat::Tsv, OutputFormat::Jsonl] {
-            let columns = default_columns(format, false);
-            assert_eq!(columns.first(), Some(&Column::Target));
-            assert_eq!(columns, ALL_COLUMNS);
-        }
-    }
-
-    #[test]
-    fn columns_default_keyword_matches_omitted_columns() {
-        for format in [
-            OutputFormat::Table,
-            OutputFormat::Csv,
-            OutputFormat::Tsv,
-            OutputFormat::Jsonl,
-        ] {
-            let omitted = output_config(format, None).render_header();
-            let explicit = output_config(format, Some("default")).render_header();
-            assert_eq!(omitted, explicit);
-        }
-    }
-
-    #[test]
-    fn custom_columns_do_not_insert_target() {
-        let config = output_config(OutputFormat::Csv, Some("seq,effective_rtt_us"));
-        let header = config.render_header().unwrap();
-
-        assert!(!header.split(',').any(|column| column == "target"));
-    }
-
-    #[test]
-    fn custom_target_column_renders_label() {
-        let config = output_config(OutputFormat::Csv, Some("target,seq,effective_rtt_us"));
-        let line = config
-            .render_event(&reply(), Some("ams"), Some(&EventRenderStats::default()))
-            .unwrap();
-
-        assert_eq!(
-            config.render_header().as_deref(),
-            Some("target,seq,effective_rtt_us")
-        );
-        assert_eq!(line, "ams,7,1200");
-    }
-
-    #[test]
-    fn default_csv_renders_target_label_in_row() {
-        let config = output_config(OutputFormat::Csv, None);
-        let line = config
-            .render_event(&reply(), Some("ams"), Some(&EventRenderStats::default()))
-            .unwrap();
-
-        assert_eq!(line.split(',').next(), Some("ams"));
-    }
-
-    #[test]
-    fn default_jsonl_renders_target_key_first() {
-        let config = output_config(OutputFormat::Jsonl, None);
-        let line = config
-            .render_event(&reply(), Some("ams"), Some(&EventRenderStats::default()))
-            .unwrap();
-
-        assert!(line.starts_with("{\"target\":\"ams\""));
-    }
-
-    #[test]
-    fn truncate_for_table_leaves_short_value_unchanged() {
-        assert_eq!(truncate_for_table("ams", 18), "ams");
-    }
-
-    #[test]
-    fn truncate_for_table_leaves_exact_width_value_unchanged() {
-        let value = "a".repeat(18);
-        assert_eq!(truncate_for_table(&value, 18), value);
-    }
-
-    #[test]
-    fn truncate_for_table_shortens_long_value_to_width() {
-        let value = "a".repeat(40);
-        let truncated = truncate_for_table(&value, 18);
-
-        assert_eq!(truncated.chars().count(), 18);
-        assert!(truncated.len() <= 18); // ASCII: byte len matches char len
-    }
-
-    #[test]
-    fn truncate_for_table_keeps_prefix_and_appends_ellipsis_deterministically() {
-        let value = "abcdefghijklmnopqrstuvwxyz";
-        let truncated = truncate_for_table(value, 18);
-
-        assert_eq!(truncated, "abcdefghijklmno...");
-        assert_eq!(truncated.chars().count(), 18);
-    }
-
-    #[test]
-    fn truncate_for_table_does_not_split_multibyte_code_points() {
-        // Each character below is multibyte in UTF-8; a byte-index slice
-        // would panic or corrupt the string on a non-boundary cut.
-        let value = "\u{1F600}".repeat(40); // 😀 repeated, well past width 18
-        let truncated = truncate_for_table(&value, 18);
-
-        // Must not panic (validated by test completing) and must remain
-        // valid UTF-8 with exactly 18 chars (15 prefix chars + "...").
-        assert_eq!(truncated.chars().count(), 18);
-        assert!(truncated.ends_with("..."));
-        assert_eq!(truncated.chars().filter(|c| *c == '\u{1F600}').count(), 15);
-    }
-
-    #[test]
-    fn table_row_with_long_target_keeps_next_column_aligned() {
-        let config = output_config(OutputFormat::Table, None);
-        let long_target = "a".repeat(40);
-        let header = config.render_header().unwrap();
-        let line = config
-            .render_event(
-                &reply(),
-                Some(&long_target),
-                Some(&EventRenderStats::default()),
-            )
-            .unwrap();
-
-        // Target column is truncated to its table width (18), so the
-        // "event" column starts at the same offset for both a normal and an
-        // overlong target label.
-        let short_config = output_config(OutputFormat::Table, None);
-        let short_line = short_config
-            .render_event(&reply(), Some("ams"), Some(&EventRenderStats::default()))
-            .unwrap();
-
-        let target_width = Column::Target.table_width();
-        let expected_event_offset = target_width + "  ".len();
-        assert_eq!(&header[expected_event_offset..][..5], "event");
-        // The event column ("echo_reply") starts at the same offset
-        // regardless of whether the target label was short or overlong.
-        assert_eq!(
-            &line[expected_event_offset..][.."echo_reply".len()],
-            "echo_reply"
-        );
-        assert_eq!(
-            &short_line[expected_event_offset..][.."echo_reply".len()],
-            "echo_reply"
-        );
-    }
-
-    #[test]
-    fn csv_preserves_full_long_target_label() {
-        let config = output_config(OutputFormat::Csv, Some("target,seq"));
-        let long_target = "a".repeat(40);
-        let line = config
-            .render_event(
-                &reply(),
-                Some(&long_target),
-                Some(&EventRenderStats::default()),
-            )
-            .unwrap();
-
-        assert_eq!(line, format!("{long_target},7"));
-    }
-
-    #[test]
-    fn tsv_preserves_full_long_target_label() {
-        let config = output_config(OutputFormat::Tsv, Some("target,seq"));
-        let long_target = "b".repeat(40);
-        let line = config
-            .render_event(
-                &reply(),
-                Some(&long_target),
-                Some(&EventRenderStats::default()),
-            )
-            .unwrap();
-
-        assert_eq!(line, format!("{long_target}\t7"));
-    }
-
-    #[test]
-    fn jsonl_preserves_full_long_target_label() {
-        let config = output_config(OutputFormat::Jsonl, Some("target,seq"));
-        let long_target = "c".repeat(40);
-        let line = config
-            .render_event(
-                &reply(),
-                Some(&long_target),
-                Some(&EventRenderStats::default()),
-            )
-            .unwrap();
-
-        assert_eq!(line, format!("{{\"target\":\"{long_target}\",\"seq\":7}}"));
-    }
-
-    #[test]
-    fn explicit_table_columns_with_target_truncate_same_as_default() {
-        let config = output_config(OutputFormat::Table, Some("target,seq"));
-        let long_target = "d".repeat(40);
-        let line = config
-            .render_event(
-                &reply(),
-                Some(&long_target),
-                Some(&EventRenderStats::default()),
-            )
-            .unwrap();
-
-        let target_width = Column::Target.table_width();
-        let expected_prefix: String = long_target
-            .chars()
-            .take(target_width - 3)
-            .chain("...".chars())
-            .collect();
-        assert!(line.starts_with(&expected_prefix));
-        assert_eq!(&line[..target_width], expected_prefix.as_str());
-    }
-}

crates/irtt-app/src/cmd/client/run.rs

@@ -1,16 +1,16 @@
-use std::collections::BTreeMap;
 use std::{
-    collections::HashSet,
-    io::{self, Write},
-    sync::atomic::AtomicBool,
+    collections::{BTreeMap, BTreeSet, HashSet, VecDeque},
+    io::{self, BufRead, Write},
+    sync::{atomic::AtomicBool, Arc, Mutex},
     thread,
     time::Duration,
 };
 
 use irtt_client::{
     managed::{
-        BlockingManagedClient, ManagedEndReason, ManagedEvent, ManagedEventSubscription,
-        ManagedEventTryRecvError, ManagedTargetEndReason, ManagedTargetOutcome, TargetInstance,
+        BlockingManagedClient, ManagedClientHandle, ManagedCommandApplyError, ManagedEndReason,
+        ManagedEvent, ManagedEventSubscription, ManagedEventTryRecvError, ManagedStatus,
+        ManagedTargetConfig, ManagedTargetEndReason, ManagedTargetOutcome, TargetInstance,
     },
     ClientEvent,
 };
@@ -20,13 +20,13 @@ use super::{
     output::{EventRenderStats, OutputConfig},
 };
 
-use crate::shared::client::expected_probe_count;
 use crate::shared::client::{
-    is_shutdown_requested,
+    expected_probe_count, is_shutdown_requested, parse_stdin_target_set,
     session::{
         drain_managed_events, peer_close_run_error, request_managed_stop_for_peer_close,
         request_managed_stop_once, should_print_final_summary, ManagedDrainState,
     },
+    ManagedRunSetup, STDIN_MAX_DESIRED_TARGETS, STDIN_OUTCOME_HISTORY_LIMIT,
 };
 
 use irtt_stats::{StatsCollector, StatsConfig};
@@ -41,6 +41,7 @@ const FINITE_STATS_MEMORY_STRONG_WARNING_BYTES: u64 = 512 * MIB;
 
 const FINITE_STATS_MEMORY_VERY_STRONG_WARNING_BYTES: u64 = GIB;
 const MANAGED_EVENT_WAIT_SLICE: Duration = Duration::from_millis(20);
+const MAX_STDIN_RECORD_BYTES: usize = 64 * 1024;
 
 pub fn run_stream(
     args: ClientArgs,
@@ -61,6 +62,9 @@ pub fn run_stream(
         args.verbose,
     )
     .map_err(|err| io::Error::new(io::ErrorKind::InvalidInput, err))?;
+    if setup.stdin_controlled {
+        return run_stdin_stream(setup, output_config, shutdown_requested);
+    }
     let continuous = args.is_continuous();
     let target_count = setup.target_count();
 
@@ -196,6 +200,561 @@ pub fn run_stream(
     Ok(())
 }
 
+#[derive(Clone)]
+struct StdinTargetSet {
+    revision: u64,
+    targets: Vec<ManagedTargetConfig>,
+}
+
+#[derive(Default)]
+struct StdinMailboxState {
+    next_revision: u64,
+    latest: Option<StdinTargetSet>,
+    eof: bool,
+    fatal: Option<String>,
+}
+
+#[derive(Default)]
+struct StdinMailbox {
+    state: Mutex<StdinMailboxState>,
+}
+
+impl StdinMailbox {
+    fn publish(&self, targets: Vec<ManagedTargetConfig>) {
+        let mut state = self
+            .state
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner);
+        state.next_revision = state.next_revision.saturating_add(1);
+        state.latest = Some(StdinTargetSet {
+            revision: state.next_revision,
+            targets,
+        });
+    }
+
+    fn finish(&self) {
+        self.state
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner)
+            .eof = true;
+    }
+
+    fn fail(&self, error: String) {
+        let mut state = self
+            .state
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner);
+        state.fatal = Some(error);
+        state.latest = None;
+    }
+
+    fn latest(&self) -> Option<StdinTargetSet> {
+        self.state
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner)
+            .latest
+            .clone()
+    }
+
+    fn clear_if_current(&self, revision: u64) {
+        let mut state = self
+            .state
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner);
+        if state
+            .latest
+            .as_ref()
+            .is_some_and(|set| set.revision == revision)
+        {
+            state.latest = None;
+        }
+    }
+
+    fn is_current(&self, revision: u64) -> bool {
+        self.state
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner)
+            .latest
+            .as_ref()
+            .is_some_and(|set| set.revision == revision)
+    }
+
+    fn fatal(&self) -> Option<String> {
+        self.state
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner)
+            .fatal
+            .clone()
+    }
+
+    fn is_finished(&self) -> bool {
+        self.state
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner)
+            .eof
+    }
+}
+
+fn read_stdin_record<R: BufRead>(
+    reader: &mut R,
+    buffer: &mut Vec<u8>,
+) -> io::Result<Option<String>> {
+    buffer.clear();
+    loop {
+        let available = reader.fill_buf()?;
+        if available.is_empty() {
+            if buffer.is_empty() {
+                return Ok(None);
+            }
+            if buffer.len() > MAX_STDIN_RECORD_BYTES {
+                return Err(io::Error::new(
+                    io::ErrorKind::InvalidData,
+                    "stdin target record exceeds the maximum size",
+                ));
+            }
+            return std::str::from_utf8(buffer)
+                .map(str::to_owned)
+                .map(Some)
+                .map_err(|_| io::Error::new(io::ErrorKind::InvalidData, "stdin is not UTF-8"));
+        }
+
+        if buffer.len() == MAX_STDIN_RECORD_BYTES + 1 {
+            if available.first() == Some(&b'\n') && buffer.last() == Some(&b'\r') {
+                reader.consume(1);
+                buffer.pop();
+                return std::str::from_utf8(buffer)
+                    .map(str::to_owned)
+                    .map(Some)
+                    .map_err(|_| io::Error::new(io::ErrorKind::InvalidData, "stdin is not UTF-8"));
+            }
+            return Err(io::Error::new(
+                io::ErrorKind::InvalidData,
+                "stdin target record exceeds the maximum size",
+            ));
+        }
+
+        if let Some(newline) = available.iter().position(|byte| *byte == b'\n') {
+            let before_newline = &available[..newline];
+            if buffer.len().saturating_add(before_newline.len()) > MAX_STDIN_RECORD_BYTES + 1 {
+                return Err(io::Error::new(
+                    io::ErrorKind::InvalidData,
+                    "stdin target record exceeds the maximum size",
+                ));
+            }
+            buffer.extend_from_slice(before_newline);
+            reader.consume(newline + 1);
+            if buffer.last() == Some(&b'\r') {
+                buffer.pop();
+            }
+            if buffer.len() > MAX_STDIN_RECORD_BYTES {
+                return Err(io::Error::new(
+                    io::ErrorKind::InvalidData,
+                    "stdin target record exceeds the maximum size",
+                ));
+            }
+            return std::str::from_utf8(buffer)
+                .map(str::to_owned)
+                .map(Some)
+                .map_err(|_| io::Error::new(io::ErrorKind::InvalidData, "stdin is not UTF-8"));
+        }
+
+        let remaining = MAX_STDIN_RECORD_BYTES + 1 - buffer.len();
+        let take = available.len().min(remaining);
+        buffer.extend_from_slice(&available[..take]);
+        reader.consume(take);
+        if buffer.len() > MAX_STDIN_RECORD_BYTES && buffer.last() != Some(&b'\r') {
+            return Err(io::Error::new(
+                io::ErrorKind::InvalidData,
+                "stdin target record exceeds the maximum size",
+            ));
+        }
+    }
+}
+
+fn read_stdin_target_sets<R: BufRead>(reader: &mut R, mailbox: &StdinMailbox) {
+    let mut line = 0_u64;
+    let mut record = Vec::with_capacity(MAX_STDIN_RECORD_BYTES + 1);
+    loop {
+        match read_stdin_record(reader, &mut record) {
+            Ok(Some(record)) => {
+                line = line.saturating_add(1);
+                if record.is_empty() {
+                    continue;
+                }
+                match parse_stdin_target_set(&record, STDIN_MAX_DESIRED_TARGETS) {
+                    Ok(targets) => {
+                        mailbox.publish(targets.into_iter().map(|target| target.managed).collect())
+                    }
+                    Err(error) => {
+                        mailbox.fail(format!("invalid --targets-stdin line {line}: {error}"));
+                        return;
+                    }
+                }
+            }
+            Ok(None) => {
+                mailbox.finish();
+                return;
+            }
+            Err(_) => {
+                mailbox.fail(format!("failed to read --targets-stdin line {}", line + 1));
+                return;
+            }
+        }
+    }
+}
+
+fn spawn_stdin_target_reader(mailbox: Arc<StdinMailbox>) -> io::Result<()> {
+    thread::Builder::new()
+        .name("irtt-targets-stdin".to_owned())
+        .spawn(move || {
+            let stdin = io::stdin();
+            read_stdin_target_sets(&mut stdin.lock(), &mailbox);
+        })
+        .map(|_| ())
+}
+
+#[derive(Clone)]
+struct RetryAfterStatus {
+    revision: u64,
+    status: Arc<ManagedStatus>,
+}
+
+fn retry_waits_for_status_change(
+    retry_after: &mut Option<RetryAfterStatus>,
+    target_set: &StdinTargetSet,
+    status: &Arc<ManagedStatus>,
+) -> bool {
+    let Some(retry) = retry_after else {
+        return false;
+    };
+    if retry.revision != target_set.revision {
+        *retry_after = None;
+        return false;
+    }
+    Arc::ptr_eq(&retry.status, status)
+}
+
+fn retry_after_capacity_rejection(
+    mailbox: &StdinMailbox,
+    target_set: &StdinTargetSet,
+    status: Arc<ManagedStatus>,
+) -> Option<RetryAfterStatus> {
+    mailbox
+        .is_current(target_set.revision)
+        .then_some(RetryAfterStatus {
+            revision: target_set.revision,
+            status,
+        })
+}
+
+fn apply_latest_stdin_target_set(
+    handle: &ManagedClientHandle,
+    mailbox: &StdinMailbox,
+    retry_after: &mut Option<RetryAfterStatus>,
+) -> Result<(), String> {
+    let Some(target_set) = mailbox.latest() else {
+        *retry_after = None;
+        return Ok(());
+    };
+    let status = handle.status();
+    if retry_waits_for_status_change(retry_after, &target_set, &status) {
+        return Ok(());
+    }
+
+    let receipt = handle
+        .update_targets(target_set.targets.clone())
+        .map_err(|_| "failed to submit --targets-stdin update".to_owned())?;
+    match receipt.blocking_wait() {
+        Ok(_) => {
+            mailbox.clear_if_current(target_set.revision);
+            *retry_after = None;
+            Ok(())
+        }
+        Err(ManagedCommandApplyError::LiveGenerationLimitExceeded { .. }) => {
+            *retry_after = retry_after_capacity_rejection(mailbox, &target_set, status);
+            Ok(())
+        }
+        Err(_) => Err("--targets-stdin update was rejected".to_owned()),
+    }
+}
+
+struct BoundedTargetSet {
+    limit: usize,
+    order: VecDeque<TargetInstance>,
+    members: HashSet<TargetInstance>,
+}
+
+impl BoundedTargetSet {
+    fn new(limit: usize) -> Self {
+        Self {
+            limit,
+            order: VecDeque::with_capacity(limit),
+            members: HashSet::with_capacity(limit),
+        }
+    }
+
+    fn insert(&mut self, target: TargetInstance) -> bool {
+        if !self.members.insert(target.clone()) {
+            return false;
+        }
+        if self.order.len() == self.limit {
+            let evicted = self
+                .order
+                .pop_front()
+                .expect("bounded target order is nonempty");
+            self.members.remove(&evicted);
+        }
+        self.order.push_back(target);
+        true
+    }
+}
+
+fn process_stdin_event<W: Write>(
+    event: ManagedEvent,
+    stream_output: &mut StreamOutput<'_, W>,
+    stats: &mut BTreeMap<TargetInstance, StatsCollector>,
+    terminal_targets: &mut BoundedTargetSet,
+) -> io::Result<()> {
+    match event {
+        ManagedEvent::TargetStateChanged { target, .. } => {
+            stats
+                .entry(target)
+                .or_insert_with(|| StatsCollector::new(stats_config(true)));
+        }
+        ManagedEvent::Client { target, event } => {
+            let collector = stats
+                .entry(target.clone())
+                .or_insert_with(|| StatsCollector::new(stats_config(true)));
+            print_events_with_stats(
+                stream_output,
+                std::slice::from_ref(&event),
+                Some(target.id.as_str()),
+                collector,
+            )?;
+        }
+        ManagedEvent::TargetFinished { outcome }
+            if terminal_targets.insert(outcome.target.clone()) =>
+        {
+            report_target_failure(&outcome);
+        }
+        _ => {}
+    }
+    Ok(())
+}
+
+fn drain_stdin_events<W: Write>(
+    events: &mut ManagedEventSubscription,
+    stream_output: &mut StreamOutput<'_, W>,
+    stats: &mut BTreeMap<TargetInstance, StatsCollector>,
+    terminal_targets: &mut BoundedTargetSet,
+    dropped_events: &mut u64,
+) -> io::Result<ManagedDrainState> {
+    drain_managed_events(events, dropped_events, |event| {
+        process_stdin_event(event, stream_output, stats, terminal_targets)
+    })
+}
+
+fn drain_final_stdin_events<W: Write>(
+    events: &mut ManagedEventSubscription,
+    stream_output: &mut StreamOutput<'_, W>,
+    stats: &mut BTreeMap<TargetInstance, StatsCollector>,
+    terminal_targets: &mut BoundedTargetSet,
+    dropped_events: &mut u64,
+) -> io::Result<()> {
+    loop {
+        match events.try_recv() {
+            Ok(event) => process_stdin_event(event, stream_output, stats, terminal_targets)?,
+            Err(ManagedEventTryRecvError::Empty | ManagedEventTryRecvError::Closed) => break,
+            Err(ManagedEventTryRecvError::Lagged(count)) => {
+                *dropped_events = dropped_events.saturating_add(count);
+            }
+        }
+    }
+    Ok(())
+}
+
+fn reconcile_stdin_stats(
+    stats: &mut BTreeMap<TargetInstance, StatsCollector>,
+    status: &ManagedStatus,
+    final_summary_targets: Option<&BTreeSet<TargetInstance>>,
+) {
+    let live = status
+        .targets
+        .iter()
+        .map(|target| target.target.clone())
+        .collect::<HashSet<_>>();
+    stats.retain(|target, _| {
+        live.contains(target)
+            || final_summary_targets.is_some_and(|targets| targets.contains(target))
+    });
+}
+
+fn snapshot_stdin_summary_targets(
+    stats: &mut BTreeMap<TargetInstance, StatsCollector>,
+    status: &ManagedStatus,
+) -> BTreeSet<TargetInstance> {
+    let targets = status
+        .targets
+        .iter()
+        .map(|target| target.target.clone())
+        .collect::<BTreeSet<_>>();
+    for target in &targets {
+        stats
+            .entry(target.clone())
+            .or_insert_with(|| StatsCollector::new(stats_config(true)));
+    }
+    targets
+}
+
+#[derive(Clone)]
+enum StdinStop {
+    Interrupted,
+    Eof,
+    Fatal(String),
+}
+
+fn stdin_stop_request(
+    shutdown_requested: &AtomicBool,
+    mailbox: &StdinMailbox,
+) -> Option<StdinStop> {
+    if is_shutdown_requested(shutdown_requested) {
+        Some(StdinStop::Interrupted)
+    } else if let Some(error) = mailbox.fatal() {
+        Some(StdinStop::Fatal(error))
+    } else if mailbox.is_finished() {
+        Some(StdinStop::Eof)
+    } else {
+        None
+    }
+}
+
+fn run_stdin_stream(
+    setup: ManagedRunSetup,
+    output_config: OutputConfig,
+    shutdown_requested: &AtomicBool,
+) -> Result<(), Box<dyn std::error::Error>> {
+    if is_shutdown_requested(shutdown_requested) {
+        return Ok(());
+    }
+    let (owner, mut events) = BlockingManagedClient::start_with_subscription(
+        setup.managed_config(),
+        setup.managed_targets(),
+    )?;
+    let handle = owner.handle();
+    let mailbox = Arc::new(StdinMailbox::default());
+    spawn_stdin_target_reader(Arc::clone(&mailbox))?;
+
+    let mut stdout = io::LineWriter::new(io::stdout().lock());
+    let mut stream_output = StreamOutput {
+        config: output_config,
+        header_printed: false,
+        print_final_summary: false,
+        show_running_only_summary_note: false,
+        out: &mut stdout,
+    };
+    let mut stats = BTreeMap::new();
+    let mut terminal_targets = BoundedTargetSet::new(STDIN_OUTCOME_HISTORY_LIMIT);
+    let mut retry_after = None;
+    let mut dropped_events = 0_u64;
+    let mut stop_requested = false;
+    let mut stop = None;
+    let mut summary_targets = None;
+    let mut subscription_closed = false;
+
+    loop {
+        let status = handle.status();
+        if stop.is_none() {
+            if let Some(requested_stop) = stdin_stop_request(shutdown_requested, &mailbox) {
+                summary_targets = Some(snapshot_stdin_summary_targets(&mut stats, &status));
+                stop = Some(requested_stop);
+                if request_managed_stop_once(&mut stop_requested) {
+                    drop(handle.stop());
+                }
+            } else if let Err(error) =
+                apply_latest_stdin_target_set(&handle, &mailbox, &mut retry_after)
+            {
+                summary_targets = Some(snapshot_stdin_summary_targets(&mut stats, &status));
+                stop = Some(StdinStop::Fatal(error));
+                if request_managed_stop_once(&mut stop_requested) {
+                    drop(handle.stop());
+                }
+            }
+        }
+
+        let drain_state = drain_stdin_events(
+            &mut events,
+            &mut stream_output,
+            &mut stats,
+            &mut terminal_targets,
+            &mut dropped_events,
+        )?;
+        reconcile_stdin_stats(&mut stats, &handle.status(), summary_targets.as_ref());
+        match drain_state {
+            ManagedDrainState::Empty => thread::sleep(MANAGED_EVENT_WAIT_SLICE),
+            ManagedDrainState::Closed => subscription_closed = true,
+            ManagedDrainState::BudgetExhausted => {}
+        }
+        if handle.status().final_outcome.is_some() || subscription_closed {
+            break;
+        }
+    }
+
+    let outcome = owner.join()?;
+    drain_final_stdin_events(
+        &mut events,
+        &mut stream_output,
+        &mut stats,
+        &mut terminal_targets,
+        &mut dropped_events,
+    )?;
+    if let Some(warning) = dropped_event_warning(dropped_events) {
+        eprintln!("{warning}");
+    }
+    for target in outcome.recent_target_outcomes.iter() {
+        if terminal_targets.insert(target.target.clone()) {
+            report_target_failure(target);
+        }
+    }
+    if outcome.discarded_target_outcomes != 0 {
+        eprintln!(
+            "irtt-rs: warning: {} final target outcomes were discarded",
+            outcome.discarded_target_outcomes
+        );
+    }
+
+    let print_summary = matches!(stop, Some(StdinStop::Interrupted | StdinStop::Eof));
+    stream_output.print_final_summary = print_summary;
+    stream_output.show_running_only_summary_note = print_summary;
+    if let Some(summary_targets) = summary_targets {
+        let multi_target = summary_targets.len() > 1;
+        for target in summary_targets {
+            let stats = stats
+                .get(&target)
+                .expect("summary snapshot retains every selected target collector");
+            if multi_target && stream_output.config.prints_summary() {
+                writeln!(stream_output.out)?;
+                writeln!(
+                    stream_output.out,
+                    "target: {} (generation {})",
+                    target.id, target.generation
+                )?;
+            }
+            stream_output.print_summary(stats)?;
+        }
+    }
+    stream_output.out.flush()?;
+
+    match stop {
+        Some(StdinStop::Fatal(error)) => Err(error.into()),
+        _ => match outcome.end_reason {
+            ManagedEndReason::DriverFailed(failure) => {
+                Err(format!("managed driver failed: {failure}").into())
+            }
+            _ => Ok(()),
+        },
+    }
+}
+
 fn process_event<W: Write>(
     event: ManagedEvent,
     stream_output: &mut StreamOutput<'_, W>,
@@ -379,112 +938,3 @@ fn finite_stats_memory_warning(args: &ClientArgs, target_count: usize) -> Option
     };
     Some(format!("irtt-rs: warning: finite exact statistics may retain about {formatted} for this run; {guidance}"))
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use irtt_client::managed::{
-        ManagedTargetFailure, ManagedTargetFailureKind, ManagedTargetFailurePhase, TargetId,
-    };
-    use std::sync::Arc;
-
-    fn long_finite_args() -> ClientArgs {
-        use clap::Parser;
-
-        ClientArgs::try_parse_from([
-            "irtt-client",
-            "--duration",
-            "4200s",
-            "--interval",
-            "100ms",
-            "127.0.0.1:2112",
-        ])
-        .unwrap()
-    }
-
-    /// Smallest target count whose aggregate estimate reaches the warning
-    /// threshold, derived from the stats crate's own estimate rather than from
-    /// any bytes-per-probe assumption held here.
-    fn first_warning_target_count(args: &ClientArgs) -> usize {
-        let probes = expected_probe_count(args.duration, args.interval);
-        (1..=1024)
-            .find(|targets| {
-                let total = probes.saturating_mul(*targets as u64);
-                stats_config(false).estimated_retained_bytes(total)
-                    >= FINITE_STATS_MEMORY_WARNING_BYTES
-            })
-            .expect("a long finite run should cross the warning threshold within 1024 targets")
-    }
-
-    #[test]
-    fn finite_stats_memory_warning_accounts_for_target_count() {
-        let args = long_finite_args();
-        let crossing = first_warning_target_count(&args);
-
-        assert!(
-            crossing > 1,
-            "this run should need more than one target to cross the threshold, \
-             otherwise the test proves nothing about target-count accounting"
-        );
-        assert!(
-            finite_stats_memory_warning(&args, crossing - 1).is_none(),
-            "an aggregate estimate below the threshold should not warn"
-        );
-        assert!(
-            finite_stats_memory_warning(&args, crossing).is_some(),
-            "an aggregate estimate at the threshold should warn"
-        );
-    }
-
-    #[test]
-    fn finite_stats_memory_warning_saturates_target_count_multiplication() {
-        assert!(finite_stats_memory_warning(&long_finite_args(), usize::MAX).is_some());
-    }
-
-    #[test]
-    fn lagged_events_are_counted_saturatingly() {
-        let mut dropped = 0_u64;
-        dropped = dropped.saturating_add(7);
-        dropped = dropped.saturating_add(3);
-        assert_eq!(dropped, 10);
-        assert_eq!(u64::MAX.saturating_add(1), u64::MAX);
-        assert!(dropped_event_warning(dropped)
-            .unwrap()
-            .contains("dropped 10 managed run events"));
-    }
-
-    #[test]
-    fn target_failure_diagnostics_include_primary_and_cleanup_failures() {
-        let target = ManagedTargetOutcome {
-            target: TargetInstance {
-                id: TargetId::from("edge"),
-                generation: 1,
-            },
-            server_addr: Arc::from("127.0.0.1:2112"),
-            remote: None,
-            end_reason: ManagedTargetEndReason::Failed(ManagedTargetFailure {
-                phase: ManagedTargetFailurePhase::Receiving,
-                kind: ManagedTargetFailureKind::Protocol,
-                message: "primary failure".into(),
-            }),
-            packets_sent: 0,
-            replies_received: 0,
-            duplicates: 0,
-            late: 0,
-            warning_events: 0,
-            cleanup_failure: Some(ManagedTargetFailure {
-                phase: ManagedTargetFailurePhase::Closing,
-                kind: ManagedTargetFailureKind::Socket,
-                message: "cleanup failure".into(),
-            }),
-        };
-
-        assert_eq!(
-            target_failure_messages(&target),
-            [
-                "irtt-rs: target edge failed (receiving protocol): primary failure",
-                "irtt-rs: target edge cleanup failed (closing socket): cleanup failure",
-            ]
-        );
-    }
-}

crates/irtt-app/src/cmd/client/summary.rs

@@ -121,257 +121,3 @@ fn write_time_row(out: &mut String, label: &str, value: &TimeStats) {
     )
     .unwrap();
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use irtt_client::{
-        ClientEvent, ClientTimestamp, PacketMeta, RttSample, ServerTiming, SignedDuration,
-    };
-    use irtt_stats::{StatsCollector, StatsConfig};
-    use std::{
-        net::{IpAddr, Ipv4Addr, SocketAddr},
-        time::{Duration, Instant, UNIX_EPOCH},
-    };
-
-    fn test_timestamp(offset: Duration) -> ClientTimestamp {
-        ClientTimestamp {
-            wall: UNIX_EPOCH + offset,
-            mono: Instant::now() + offset,
-        }
-    }
-
-    fn test_remote() -> SocketAddr {
-        SocketAddr::new(IpAddr::V4(Ipv4Addr::LOCALHOST), 2112)
-    }
-
-    #[test]
-    fn empty_summary_omits_optional_metric_sections() {
-        let summary = StatsCollector::new(StatsConfig::finite()).snapshot();
-        let output = format_summary(&summary);
-
-        assert!(output.contains("Metric"));
-        assert!(output.contains("Min"));
-        assert!(output.contains("Mean"));
-        assert!(output.contains("Median"));
-        assert!(output.contains("Max"));
-        assert!(output.contains("Stddev"));
-        assert!(output.contains("packets: sent=0 received=0 unique=0 lost=0"));
-        assert!(!output.contains("RTT                  0"));
-        assert!(!output.contains("server processing"));
-    }
-
-    #[test]
-    fn summary_formats_counts_and_available_metrics() {
-        let mut collector = StatsCollector::new(StatsConfig::finite());
-        let sent_at = test_timestamp(Duration::from_secs(1));
-        let received_at = test_timestamp(Duration::from_secs(1) + Duration::from_micros(1500));
-
-        collector.process(&ClientEvent::EchoSent {
-            seq: 1,
-            remote: test_remote(),
-            scheduled_at: sent_at.mono,
-            sent_at,
-            bytes: 64,
-            send_call: Duration::from_micros(10),
-            timer_error: Duration::from_micros(2),
-        });
-        collector.process(&ClientEvent::EchoReply {
-            seq: 1,
-            remote: test_remote(),
-            sent_at,
-            received_at,
-            rtt: RttSample {
-                raw: Duration::from_micros(1500),
-                adjusted: Some(SignedDuration::from_nanos(1_200_000)),
-                effective: SignedDuration::from_nanos(1_200_000),
-            },
-            server_timing: Some(ServerTiming {
-                receive_wall_ns: None,
-                receive_mono_ns: None,
-                send_wall_ns: None,
-                send_mono_ns: None,
-                midpoint_wall_ns: None,
-                midpoint_mono_ns: None,
-                processing: Some(Duration::from_micros(300)),
-            }),
-            one_way: None,
-            received_stats: None,
-            bytes: 64,
-            packet_meta: PacketMeta::default(),
-        });
-
-        let output = format_summary(&collector.snapshot());
-
-        assert!(output.contains("packets: sent=1 received=1 unique=1 lost=0 loss=0.00%"));
-        assert!(output.contains("bytes: sent=64 received=64"));
-        assert!(output.contains("RTT"));
-        assert!(output.contains("1.2ms"));
-        assert!(!output.contains("raw RTT"));
-        assert!(!output.contains("adjusted RTT"));
-        assert!(output.contains("server processing"));
-        assert!(output.contains("300.0µs"));
-        assert!(output.contains("send call"));
-        assert!(output.contains("10.0µs"));
-        assert!(output.contains("timer error"));
-        assert!(output.contains("2.0µs"));
-        assert!(!output.contains("medians unavailable"));
-    }
-
-    /// Returns the Median cell of the row with this label.
-    fn median_cell(output: &str, label: &str) -> String {
-        let row = output
-            .lines()
-            .find(|line| line.trim_start().starts_with(label))
-            .unwrap_or_else(|| panic!("summary should contain a {label:?} row:\n{output}"));
-        // Metric, Count, Min, Mean, Median, ...
-        // Counting from the right keeps multi-word labels out of the way.
-        row.split_whitespace()
-            .rev()
-            .nth(2)
-            .unwrap_or_else(|| panic!("row {row:?} should have a Median cell"))
-            .to_owned()
-    }
-
-    /// Collects probes whose send-call, timer-error, and server-processing
-    /// values each have a median distinct from their min, mean, and max, so
-    /// the rendered cell can only come from a real median calculation.
-    fn spread_finite_summary(config: StatsConfig) -> Snapshot {
-        let mut collector = StatsCollector::new(config);
-        for (seq, (send_call_us, timer_error_us, processing_us)) in
-            [(10_u64, 2_u64, 100_u64), (40, 12, 700), (20, 4, 300)]
-                .into_iter()
-                .enumerate()
-        {
-            let seq = seq as u32;
-            let offset = Duration::from_secs(1) + Duration::from_millis(u64::from(seq));
-            let sent_at = test_timestamp(offset);
-            let received_at = test_timestamp(offset + Duration::from_micros(1500));
-
-            collector.process(&ClientEvent::EchoSent {
-                seq,
-                remote: test_remote(),
-                scheduled_at: sent_at.mono,
-                sent_at,
-                bytes: 64,
-                send_call: Duration::from_micros(send_call_us),
-                timer_error: Duration::from_micros(timer_error_us),
-            });
-            collector.process(&ClientEvent::EchoReply {
-                seq,
-                remote: test_remote(),
-                sent_at,
-                received_at,
-                rtt: RttSample {
-                    raw: Duration::from_micros(1500),
-                    adjusted: None,
-                    effective: SignedDuration::from_nanos(1_500_000),
-                },
-                server_timing: Some(ServerTiming {
-                    receive_wall_ns: None,
-                    receive_mono_ns: None,
-                    send_wall_ns: None,
-                    send_mono_ns: None,
-                    midpoint_wall_ns: None,
-                    midpoint_mono_ns: None,
-                    processing: Some(Duration::from_micros(processing_us)),
-                }),
-                one_way: None,
-                received_stats: None,
-                bytes: 64,
-                packet_meta: PacketMeta::default(),
-            });
-        }
-        collector.snapshot()
-    }
-
-    #[test]
-    fn finite_summary_shows_medians_for_send_call_timer_error_and_processing() {
-        let output = format_summary(&spread_finite_summary(StatsConfig::finite()));
-
-        // Medians of 10/20/40, 2/4/12, and 100/300/700 µs. None of these
-        // equals the row's min, mean, or max.
-        assert_eq!(median_cell(&output, "send call"), "20.0µs");
-        assert_eq!(median_cell(&output, "timer error"), "4.0µs");
-        assert_eq!(median_cell(&output, "server processing"), "300.0µs");
-    }
-
-    #[test]
-    fn continuous_summary_still_shows_no_medians_for_those_rows() {
-        let output = format_summary(&spread_finite_summary(StatsConfig::continuous()));
-
-        for label in ["send call", "timer error", "server processing"] {
-            assert_eq!(
-                median_cell(&output, label),
-                "-",
-                "continuous mode retains no exact samples for {label}"
-            );
-        }
-    }
-
-    #[test]
-    fn verbose_summary_includes_raw_and_adjusted_rtt_rows() {
-        let mut collector = StatsCollector::new(StatsConfig::finite());
-        let received_at = test_timestamp(Duration::from_secs(1) + Duration::from_micros(1500));
-        collector.process(&ClientEvent::EchoReply {
-            seq: 1,
-            remote: test_remote(),
-            sent_at: test_timestamp(Duration::from_secs(1)),
-            received_at,
-            rtt: RttSample {
-                raw: Duration::from_micros(1500),
-                adjusted: Some(SignedDuration::from_nanos(1_200_000)),
-                effective: SignedDuration::from_nanos(1_200_000),
-            },
-            server_timing: None,
-            one_way: None,
-            received_stats: None,
-            bytes: 64,
-            packet_meta: PacketMeta::default(),
-        });
-
-        let output = format_summary_with_options(
-            &collector.snapshot(),
-            SummaryFormatOptions {
-                verbose: true,
-                ..SummaryFormatOptions::default()
-            },
-        );
-
-        assert!(output.contains("raw RTT"));
-        assert!(output.contains("adjusted RTT"));
-    }
-
-    #[test]
-    fn running_only_note_is_format_option() {
-        let summary = StatsCollector::new(StatsConfig::continuous()).snapshot();
-        let output = format_summary_with_options(
-            &summary,
-            SummaryFormatOptions {
-                show_running_only_note: true,
-                ..SummaryFormatOptions::default()
-            },
-        );
-
-        assert!(output.contains("irtt-rs summary"));
-        assert!(output.contains("medians unavailable"));
-        assert!(output.contains("continuous mode"));
-    }
-
-    #[test]
-    fn signed_stats_can_format_negative_values() {
-        let stats = TimeStats {
-            count: 1,
-            total_ns: -500,
-            min_ns: Some(-500),
-            max_ns: Some(-500),
-            mean_ns: -500.0,
-            median_ns: Some(-500.0),
-            variance_ns2: 0.0,
-        };
-
-        let mut out = String::new();
-        write_time_row(&mut out, "RTT", &stats);
-        assert!(out.contains("-500ns"));
-    }
-}

crates/irtt-app/src/cmd/format.rs

@@ -115,93 +115,3 @@ pub(crate) fn format_optional_count(value: Option<u64>) -> String {
 fn absent() -> String {
     ABSENT.to_owned()
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn nanosecond_scalars_select_units_at_the_defined_boundaries() {
-        assert_eq!(format_ns_f64(0.0), "0ns");
-        assert_eq!(format_ns_f64(999.0), "999ns");
-        assert_eq!(format_ns_f64(1_000.0), "1.0µs");
-        assert_eq!(format_ns_f64(999_999.0), "1000.0µs");
-        assert_eq!(format_ns_f64(1_000_000.0), "1.0ms");
-        assert_eq!(format_ns_f64(999_999_999.0), "1000.0ms");
-        assert_eq!(format_ns_f64(1_000_000_000.0), "1.000s");
-        assert_eq!(format_ns_f64(1_500_000_000.0), "1.500s");
-    }
-
-    #[test]
-    fn negative_nanosecond_scalars_keep_their_sign() {
-        assert_eq!(format_ns_f64(-500.0), "-500ns");
-        assert_eq!(format_ns_f64(-1_500.0), "-1.5µs");
-        assert_eq!(format_ns_f64(-2_500_000.0), "-2.5ms");
-        assert_eq!(format_ns_f64(-1_000_000_000.0), "-1.000s");
-        assert_eq!(format_ns_i128(-1_500), "-1.5µs");
-    }
-
-    #[test]
-    fn exact_and_floating_nanosecond_scalars_agree() {
-        for value in [0_i128, 1, 999, 1_000, 1_234_567, -1_234_567, 5_000_000_000] {
-            assert_eq!(format_ns_i128(value), format_ns_f64(value as f64));
-        }
-    }
-
-    #[test]
-    fn microseconds_use_the_micro_sign() {
-        assert!(format_ns_f64(1_500.0).ends_with("µs"));
-        assert!(!format_ns_f64(1_500.0).contains("us"));
-    }
-
-    #[test]
-    fn durations_render_as_nanosecond_scalars() {
-        assert_eq!(format_duration(Duration::from_millis(25)), "25.0ms");
-        assert_eq!(format_duration(Duration::from_secs(1)), "1.000s");
-    }
-
-    #[test]
-    #[cfg(feature = "client")]
-    fn signed_durations_render_as_nanosecond_scalars() {
-        assert_eq!(
-            format_signed_duration(SignedDuration::from_nanos(-1_500)),
-            "-1.5µs"
-        );
-    }
-
-    #[test]
-    fn absent_and_non_finite_scalars_render_as_a_placeholder() {
-        assert_eq!(format_optional_ns_i128(None), ABSENT);
-        assert_eq!(format_ns_f64(f64::NAN), ABSENT);
-        assert_eq!(format_ns_f64(f64::INFINITY), ABSENT);
-        assert_eq!(format_percent(f64::NAN), ABSENT);
-    }
-
-    #[test]
-    #[cfg(feature = "client")]
-    fn absent_optional_ns_f64_renders_as_a_placeholder() {
-        assert_eq!(format_optional_ns_f64(None), ABSENT);
-    }
-
-    #[test]
-    #[cfg(feature = "tui")]
-    fn absent_counts_and_ratios_render_as_a_placeholder() {
-        assert_eq!(format_optional_count(None), ABSENT);
-        assert_eq!(format_percent_ratio(1, 0), ABSENT);
-    }
-
-    #[test]
-    fn percentages_have_one_spelling() {
-        assert_eq!(format_percent(0.0), "0.00%");
-        assert_eq!(format_percent(12.345), "12.35%");
-    }
-
-    #[test]
-    #[cfg(feature = "tui")]
-    fn percent_ratios_and_counts_have_one_spelling() {
-        assert_eq!(format_percent_ratio(1, 4), "25.00%");
-        assert_eq!(format_percent_ratio(5, 4), "100.00%");
-        assert_eq!(format_count(42), "42");
-        assert_eq!(format_optional_count(Some(0)), "0");
-    }
-}

crates/irtt-app/src/cmd/server/args.rs

@@ -23,7 +23,8 @@ pub struct ServerArgs {
     #[arg(
         long,
         value_name = "ADDR",
-        long_help = "Local UDP address to bind, as ADDR:PORT, for example 127.0.0.1:2112 or [::1]:2112. Host names are not resolved.\n\nRepeat the option to serve several addresses from one process, in the order given. Every listener applies the same policy options, but each keeps its own sessions and tokens, so a session belongs to the address it was opened on. Binding is all or nothing: if any address cannot be bound, none are served.\n\nWith no --bind at all, the server binds the wildcard IRTT port on both address families, [::]:2112 then 0.0.0.0:2112, on platforms with wildcard reply-source support; elsewhere it fails and asks for an explicit address instead of guessing one. Any explicit --bind replaces that default pair rather than adding to it.\n\nA wildcard bind such as 0.0.0.0:2112 answers each request from the address it was sent to, using per-packet destination metadata. That is supported on Linux, macOS and FreeBSD; on other systems a wildcard bind is refused and an explicit interface address is required.\n\nA port of 0 selects an unused port per listener, so two such binds get two different ports."
+        env = "IRTT_SERVER_BIND",
+        long_help = "Local UDP address to bind, as ADDR:PORT, for example 127.0.0.1:2112 or [::1]:2112. Host names are not resolved.\n\nRepeat the option to serve several addresses from one process, in the order given. Every listener applies the same policy options, but each keeps its own sessions and tokens, so a session belongs to the address it was opened on. Binding is all or nothing: if any address cannot be bound, none are served.\n\nWith no --bind at all, the server binds the wildcard IRTT port on both address families, [::]:2112 then 0.0.0.0:2112, on platforms with wildcard reply-source support; elsewhere it fails and asks for an explicit address instead of guessing one. Any explicit --bind replaces that default pair rather than adding to it.\n\nA wildcard bind such as 0.0.0.0:2112 answers each request from the address it was sent to, using per-packet destination metadata. That is supported on Linux, macOS and FreeBSD; on other systems a wildcard bind is refused and an explicit interface address is required.\n\nA port of 0 selects an unused port per listener, so two such binds get two different ports.\n\nIRTT_SERVER_BIND sets the same thing for deployments that configure by environment (systemd, Docker, ...), and takes exactly one address, the same as one --bind. Leave it unset on ordinary hosts: the wildcard default above is already what you want there. A --bind on the command line overrides it entirely."
     )]
     pub bind: Vec<SocketAddr>,
 
@@ -32,7 +33,8 @@ pub struct ServerArgs {
         long,
         value_name = "KEY",
         value_parser = parse_hmac_key,
-        long_help = "HMAC key, taken as the UTF-8 bytes of this argument.\n\nAuthentication is global: with a key configured, every request must carry a valid MAC and every reply is authenticated. Without one, authenticated requests are dropped. The key is visible in the process arguments."
+        env = "IRTT_SERVER_HMAC",
+        long_help = "HMAC key, taken as the UTF-8 bytes of this argument.\n\nAuthentication is global: with a key configured, every request must carry a valid MAC and every reply is authenticated. Without one, authenticated requests are dropped. The key is visible in the process arguments, or in the environment as IRTT_SERVER_HMAC."
     )]
     pub hmac: Option<String>,
 
@@ -40,6 +42,7 @@ pub struct ServerArgs {
     #[arg(
         long,
         value_name = "COUNT",
+        env = "IRTT_SERVER_MAX_SESSIONS",
         long_help = "Maximum number of simultaneously live sessions per listener. Once a listener's table is full, a session-creating open to it is dropped silently; nothing is evicted. Zero refuses every session-creating open.\n\nThis is a per-listener bound, not a process-wide one: with two --bind options, each listener admits up to this many sessions."
     )]
     pub max_sessions: Option<usize>,
@@ -48,6 +51,7 @@ pub struct ServerArgs {
     #[arg(
         long,
         value_name = "BYTES",
+        env = "IRTT_SERVER_MAX_PACKET_LENGTH",
         long_help = "Maximum echo datagram size a session may negotiate, in bytes. A longer requested length is reduced during negotiation, an open whose mandatory field block would not fit is refused, and inbound echo requests are admitted against the same limit. This is a resource bound, not an MTU."
     )]
     pub max_packet_length: Option<usize>,
@@ -57,6 +61,7 @@ pub struct ServerArgs {
         long,
         value_name = "DURATION",
         value_parser = parse_duration_allow_zero,
+        env = "IRTT_SERVER_MIN_INTERVAL",
         long_help = "Floor on the send interval a session may negotiate. The negotiated interval is still capped at a quarter of the idle timeout afterwards, so a value above that cap is not what actually gets negotiated.\n\nA session's reply allowance refills at the shorter of this floor and the interval it actually negotiated. Ordinarily that is this floor itself; it is the shorter, negotiated value only where the idle-timeout cap above pulled the negotiated interval below it. Use 0 for no time-based throttling."
     )]
     pub min_interval: Option<Duration>,
@@ -65,6 +70,7 @@ pub struct ServerArgs {
     #[arg(
         long,
         value_name = "COUNT",
+        env = "IRTT_SERVER_BURST",
         long_help = "Echo replies one session may have answered before its allowance has to refill. Use 0 for no allowance at all, which rate-limits every echo request whatever the interval is."
     )]
     pub burst: Option<u32>,
@@ -74,6 +80,7 @@ pub struct ServerArgs {
         long,
         value_name = "DURATION",
         value_parser = parse_duration_allow_zero,
+        env = "IRTT_SERVER_IDLE_TIMEOUT",
         long_help = "Release a session after this long without a served or rate-limited echo request. The deadline runs from the open, and release is silent. Use 0 to expire a session at the next evaluation; it is not a way to disable expiry."
     )]
     pub idle_timeout: Option<Duration>,
@@ -83,6 +90,7 @@ pub struct ServerArgs {
         long,
         value_name = "DURATION",
         value_parser = parse_positive_duration,
+        env = "IRTT_SERVER_MAX_DURATION",
         long_help = "Maximum test duration a session may negotiate. A longer request is reduced to it, and a continuous request is answered with it. Omit this flag for no maximum; a maximum of zero cannot be expressed, because a negotiated duration of zero means continuous."
     )]
     pub max_duration: Option<Duration>,
@@ -92,14 +100,28 @@ pub struct ServerArgs {
         long,
         value_name = "MODE",
         value_enum,
+        env = "IRTT_SERVER_TIMESTAMP_ALLOWANCE",
         long_help = "How many timestamps this server will provide.\n\ndual: honor a request for send, receive, both or midpoint timestamps.\nsingle: provide at most one timestamp instant; a request for both is negotiated to midpoint.\nnone: provide no timestamps at all.\n\nThe requested clock source is never changed, only which instants are reported, so a single instant is still reported once per requested clock. Omit this flag to honor every requested placement."
     )]
     pub timestamp_allowance: Option<TimestampAllowanceArg>,
 
     /// Refuse to provide requested DSCP marking.
+    //
+    // `FalseyValueParser` rather than clap's default `bool` parser for a flag,
+    // which is what makes IRTT_SERVER_NO_DSCP usable from the environment at
+    // all. A flag's default parser accepts only the literals `true` and
+    // `false`, so the ordinary container/orchestrator spelling
+    // `IRTT_SERVER_NO_DSCP=1` did not enable the flag — it failed argument
+    // parsing and the server refused to start. Falsey semantics are clap's own
+    // documented recipe for a boolean environment flag: `0`, `false`, `no`,
+    // `n`, `off` and empty are off, anything else is on, and an absent
+    // variable is off as before. The command-line flag is unaffected: it still
+    // takes no value and still means "on".
     #[arg(
         long,
-        long_help = "Refuse to provide requested traffic-class marking. Any requested DSCP is negotiated to zero, so the client is told its echo replies will be unmarked, and they are sent unmarked. The session is not refused."
+        env = "IRTT_SERVER_NO_DSCP",
+        value_parser = clap::builder::FalseyValueParser::new(),
+        long_help = "Refuse to provide requested traffic-class marking. Any requested DSCP is negotiated to zero, so the client is told its echo replies will be unmarked, and they are sent unmarked. The session is not refused.\n\nIRTT_SERVER_NO_DSCP sets the same thing from the environment: 0, false, no, n, off and an empty value leave marking enabled, and any other value disables it."
     )]
     pub no_dscp: bool,
 }
@@ -235,248 +257,3 @@ fn parse_duration_units(input: &str) -> Result<Duration, String> {
         )),
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use std::net::{Ipv4Addr, Ipv6Addr};
-
-    use super::*;
-
-    fn parse(args: &[&str]) -> Result<ServerArgs, clap::Error> {
-        let mut argv = vec!["irtt-server"];
-        argv.extend_from_slice(args);
-        ServerArgs::try_parse_from(argv)
-    }
-
-    fn bound(args: &[&str]) -> ServerArgs {
-        let mut argv = vec!["--bind", "127.0.0.1:2112"];
-        argv.extend_from_slice(args);
-        parse(&argv).unwrap()
-    }
-
-    #[test]
-    fn bind_is_optional_and_parses_both_families() {
-        let ipv4 = parse(&["--bind", "127.0.0.1:2112"]).unwrap();
-        assert_eq!(ipv4.bind, [SocketAddr::from((Ipv4Addr::LOCALHOST, 2112))]);
-
-        let ipv6 = parse(&["--bind", "[::1]:2112"]).unwrap();
-        assert_eq!(ipv6.bind, [SocketAddr::from((Ipv6Addr::LOCALHOST, 2112))]);
-
-        assert!(parse(&["--bind", "127.0.0.1"]).is_err());
-        assert!(parse(&["--bind", "localhost:2112"]).is_err());
-        // Still one address per option: comma-separated syntax is not a thing
-        // here, and accepting it silently would be worse than rejecting it.
-        assert!(parse(&["--bind", "127.0.0.1:2112,[::1]:2112"]).is_err());
-    }
-
-    #[test]
-    fn no_explicit_bind_resolves_to_the_wildcard_default_pair() {
-        let args = parse(&[]).unwrap();
-        assert!(
-            args.bind.is_empty(),
-            "the empty list is the parsed representation of \"no explicit bind\""
-        );
-        assert_eq!(
-            args.resolve_binds(),
-            [
-                SocketAddr::from((Ipv6Addr::UNSPECIFIED, 2112)),
-                SocketAddr::from((Ipv4Addr::UNSPECIFIED, 2112)),
-            ],
-            "zero explicit binds means the ordinary port on both wildcard families, IPv6 first"
-        );
-    }
-
-    #[test]
-    fn an_explicit_bind_replaces_the_defaults_rather_than_augmenting_them() {
-        let args = parse(&["--bind", "127.0.0.1:2112"]).unwrap();
-        assert_eq!(
-            args.resolve_binds(),
-            [SocketAddr::from((Ipv4Addr::LOCALHOST, 2112))],
-            "one explicit bind means exactly that one listener, not that listener plus defaults"
-        );
-    }
-
-    #[test]
-    fn repeated_explicit_binds_are_unaffected_by_the_default_resolution() {
-        let args = parse(&["--bind", "127.0.0.1:2112", "--bind", "[::1]:2112"]).unwrap();
-        assert_eq!(args.resolve_binds(), args.bind);
-    }
-
-    #[test]
-    fn bind_is_repeatable_and_keeps_the_requested_order() {
-        let args = parse(&[
-            "--bind",
-            "[::1]:2112",
-            "--bind",
-            "127.0.0.1:2112",
-            "--bind",
-            "127.0.0.1:2113",
-        ])
-        .unwrap();
-
-        assert_eq!(
-            args.bind,
-            [
-                SocketAddr::from((Ipv6Addr::LOCALHOST, 2112)),
-                SocketAddr::from((Ipv4Addr::LOCALHOST, 2112)),
-                SocketAddr::from((Ipv4Addr::LOCALHOST, 2113)),
-            ],
-            "listeners are served in the order they were requested"
-        );
-    }
-
-    #[test]
-    fn the_configuration_is_one_policy_however_many_listeners_there_are() {
-        // Addresses never enter the server configuration: every listener is
-        // built from a clone of this one value.
-        let one = parse(&["--bind", "127.0.0.1:2112", "--max-sessions", "4"])
-            .unwrap()
-            .server_config();
-        let several = parse(&[
-            "--bind",
-            "127.0.0.1:2112",
-            "--bind",
-            "[::1]:2112",
-            "--max-sessions",
-            "4",
-        ])
-        .unwrap()
-        .server_config();
-
-        assert_eq!(one, several);
-        assert_eq!(several.max_sessions(), 4, "and it is a per-listener bound");
-    }
-
-    #[test]
-    fn omitted_policy_options_keep_the_library_defaults() {
-        assert_eq!(bound(&[]).server_config(), ServerConfig::default());
-    }
-
-    #[test]
-    fn policy_options_map_onto_the_server_config() {
-        let config = bound(&[
-            "--hmac",
-            "secret",
-            "--max-sessions",
-            "512",
-            "--max-packet-length",
-            "1472",
-            "--min-interval",
-            "20ms",
-            "--burst",
-            "3",
-            "--idle-timeout",
-            "30s",
-            "--max-duration",
-            "2m",
-        ])
-        .server_config();
-
-        assert_eq!(config.hmac_key(), Some(b"secret".as_slice()));
-        assert_eq!(config.max_sessions(), 512);
-        assert_eq!(config.max_packet_length(), 1472);
-        assert_eq!(config.min_send_interval(), Duration::from_millis(20));
-        assert_eq!(config.burst_allowance(), 3);
-        assert_eq!(config.idle_timeout(), Duration::from_secs(30));
-        assert_eq!(config.max_test_duration(), Some(Duration::from_secs(120)));
-    }
-
-    #[test]
-    fn the_capability_restrictions_map_onto_the_server_config() {
-        let config = bound(&["--timestamp-allowance", "single", "--no-dscp"]).server_config();
-
-        assert_eq!(
-            config.timestamp_allowance(),
-            TimestampAllowance::Single,
-            "a request for both timestamps is negotiated to midpoint"
-        );
-        assert!(!config.dscp_allowed());
-    }
-
-    #[test]
-    fn every_timestamp_allowance_mode_parses() {
-        for (argument, expected) in [
-            ("dual", TimestampAllowance::Dual),
-            ("single", TimestampAllowance::Single),
-            ("none", TimestampAllowance::None),
-        ] {
-            assert_eq!(
-                bound(&["--timestamp-allowance", argument])
-                    .server_config()
-                    .timestamp_allowance(),
-                expected,
-                "--timestamp-allowance {argument}"
-            );
-        }
-
-        assert!(parse(&[
-            "--bind",
-            "127.0.0.1:2112",
-            "--timestamp-allowance",
-            "midpoint"
-        ])
-        .is_err());
-        assert!(parse(&["--bind", "127.0.0.1:2112", "--timestamp-allowance", "both"]).is_err());
-    }
-
-    #[test]
-    fn the_capability_restrictions_are_off_when_their_flags_are_absent() {
-        // Explicitly, and not only through the whole-config comparison above:
-        // these are the two values that would silently change every existing
-        // deployment's negotiation if the CLI restated them.
-        let config = bound(&["--idle-timeout", "30s"]).server_config();
-
-        assert_eq!(config.timestamp_allowance(), TimestampAllowance::Dual);
-        assert!(config.dscp_allowed());
-    }
-
-    #[test]
-    fn explicit_zero_policy_values_are_preserved() {
-        let config = bound(&[
-            "--min-interval",
-            "0",
-            "--idle-timeout",
-            "0ms",
-            "--burst",
-            "0",
-            "--max-sessions",
-            "0",
-            "--max-packet-length",
-            "0",
-        ])
-        .server_config();
-
-        assert_eq!(config.min_send_interval(), Duration::ZERO);
-        assert_eq!(config.idle_timeout(), Duration::ZERO);
-        assert_eq!(config.burst_allowance(), 0);
-        assert_eq!(config.max_sessions(), 0);
-        assert_eq!(config.max_packet_length(), 0);
-    }
-
-    #[test]
-    fn durations_require_a_supported_unit() {
-        assert!(parse(&["--bind", "127.0.0.1:2112", "--idle-timeout", "30"]).is_err());
-        assert!(parse(&["--bind", "127.0.0.1:2112", "--min-interval", "20us"]).is_err());
-        assert!(parse(&["--bind", "127.0.0.1:2112", "--max-duration", "2h"]).is_err());
-        assert!(parse(&["--bind", "127.0.0.1:2112", "--idle-timeout", "ms"]).is_err());
-    }
-
-    #[test]
-    fn an_empty_hmac_key_is_rejected() {
-        let err = parse(&["--bind", "127.0.0.1:2112", "--hmac", ""]).unwrap_err();
-        assert!(err.to_string().contains("HMAC key must not be empty"));
-    }
-
-    #[test]
-    fn a_whitespace_only_hmac_key_is_accepted_literally() {
-        let config = bound(&["--hmac", " "]).server_config();
-        assert_eq!(config.hmac_key(), Some(b" ".as_slice()));
-    }
-
-    #[test]
-    fn a_zero_maximum_duration_is_not_a_spelling_of_no_maximum() {
-        assert!(parse(&["--bind", "127.0.0.1:2112", "--max-duration", "0"]).is_err());
-        assert!(parse(&["--bind", "127.0.0.1:2112", "--max-duration", "0s"]).is_err());
-        assert_eq!(bound(&[]).server_config().max_test_duration(), None);
-    }
-}

crates/irtt-app/src/cmd/server/run.rs

@@ -105,98 +105,3 @@ async fn shutdown_signal(shutdown_requested: &AtomicBool) {
         tokio::time::sleep(SHUTDOWN_POLL_INTERVAL).await;
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use clap::Parser;
-
-    use super::*;
-
-    /// The ordinary invocation, and the one that keeps the single-listener case
-    /// on the same orchestration path as every other.
-    #[test]
-    fn an_already_requested_shutdown_binds_one_listener_and_returns() {
-        let args = ServerArgs::try_parse_from(["irtt-server", "--bind", "127.0.0.1:0"]).unwrap();
-        let shutdown_requested = AtomicBool::new(true);
-
-        run_server(args, &shutdown_requested).unwrap();
-    }
-
-    #[test]
-    fn an_already_requested_shutdown_binds_every_listener_and_returns() {
-        let args = ServerArgs::try_parse_from([
-            "irtt-server",
-            "--bind",
-            "127.0.0.1:0",
-            "--bind",
-            "127.0.0.1:0",
-        ])
-        .unwrap();
-        let shutdown_requested = AtomicBool::new(true);
-
-        run_server(args, &shutdown_requested).unwrap();
-    }
-
-    fn default_binds() -> Vec<SocketAddr> {
-        ServerArgs::try_parse_from(["irtt-server"])
-            .unwrap()
-            .resolve_binds()
-    }
-
-    #[test]
-    fn implicit_default_losing_an_unsupported_family_falls_back_to_the_other() {
-        let binds = default_binds();
-        let failed = binds[0];
-
-        let remaining = implicit_default_fallback(true, false, &binds, failed).unwrap();
-
-        assert_eq!(remaining, [binds[1]]);
-    }
-
-    #[test]
-    fn a_supported_familys_failure_never_falls_back() {
-        // The family itself works fine here; whatever made this specific
-        // bind fail (port in use, permission, ...) is a real problem this
-        // invocation should surface, not paper over.
-        let binds = default_binds();
-
-        assert_eq!(
-            implicit_default_fallback(true, true, &binds, binds[0]),
-            None,
-            "family_available: true means this is not a family-support problem"
-        );
-    }
-
-    #[test]
-    fn explicit_binds_never_fall_back() {
-        let binds = default_binds();
-
-        assert_eq!(
-            implicit_default_fallback(false, false, &binds, binds[0]),
-            None
-        );
-    }
-
-    #[test]
-    fn a_failure_outside_the_requested_set_does_not_fall_back() {
-        let binds = default_binds();
-        let unrelated = SocketAddr::from(([127, 0, 0, 1], 2113));
-
-        assert_eq!(
-            implicit_default_fallback(true, false, &binds, unrelated),
-            None,
-            "the failing address must actually be one this invocation asked for"
-        );
-    }
-
-    #[test]
-    fn losing_the_only_remaining_default_address_does_not_fall_back() {
-        let single = [SocketAddr::from(([0, 0, 0, 0], 2112))];
-
-        assert_eq!(
-            implicit_default_fallback(true, false, &single, single[0]),
-            None,
-            "no address would be left to retry with"
-        );
-    }
-}

crates/irtt-app/src/cmd/tui/args.rs

@@ -2,8 +2,6 @@ use std::time::Duration;
 
 use clap::Parser;
 
-#[cfg(test)]
-use crate::shared::client::TimestampArg;
 use crate::shared::client::{
     parse_target, parse_test_duration, prepare_managed_run, CommonClientArgs, GroupPacingArg,
     ManagedRunSetup, TargetArg, TargetSelection,
@@ -14,13 +12,13 @@ pub const DEFAULT_TUI_DURATION: Duration = Duration::ZERO;
 #[derive(Debug, Clone, Parser)]
 #[command(name = "irtt-tui", about = "Minimal IRTT-compatible TUI client")]
 pub struct TuiArgs {
-    /// Server address/host, optionally prefixed with LABEL=. Repeat for multi-target mode.
+    /// Server address/host, optionally prefixed with LABEL= and suffixed with @hmac=KEY. Repeat for multi-target mode.
     #[arg(
         value_name = "TARGET",
         num_args = 1..,
         required = true,
         value_parser = parse_target,
-        long_help = "Server address/host, optionally prefixed with LABEL=. Repeat for multi-target mode.\n\nExplicit labels are used in the legend and status table.\n\nExamples:\n  irtt-tui host.example\n  irtt-tui eu=host.example\n  irtt-tui eu=host-a.example us=host-b.example"
+        long_help = "Server address/host, optionally prefixed with LABEL= and suffixed with @hmac=KEY. Repeat for multi-target mode.\n\nExplicit labels are used in the legend and status table. A target without @hmac= inherits --hmac; @hmac= disables it for that target.\n\nExamples:\n  irtt-tui host.example\n  irtt-tui eu=host.example\n  irtt-tui eu=host-a.example@hmac=secret us=host-b.example"
     )]
     pub targets: Vec<TargetArg>,
 
@@ -58,6 +56,7 @@ impl TuiArgs {
             TargetSelection {
                 targets: &self.targets,
                 pacing: self.pacing,
+                stdin_controlled: false,
             },
         )
     }
@@ -65,11 +64,6 @@ impl TuiArgs {
     pub fn is_continuous(&self) -> bool {
         self.duration == Duration::ZERO
     }
-
-    #[cfg(test)]
-    pub fn timestamp_mode(&self) -> TimestampArg {
-        self.common.tstamp
-    }
 }
 
 impl std::ops::Deref for TuiArgs {
@@ -79,209 +73,3 @@ impl std::ops::Deref for TuiArgs {
         &self.common
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use clap::{CommandFactory, Parser};
-
-    #[derive(Parser)]
-    struct SharedOnlyArgs {
-        #[command(flatten)]
-        common: CommonClientArgs,
-    }
-
-    fn parse(args: &[&str]) -> Result<TuiArgs, clap::Error> {
-        let mut argv = vec!["irtt-tui"];
-        argv.extend_from_slice(args);
-        TuiArgs::try_parse_from(argv)
-    }
-
-    fn parse_shared(args: &[&str]) -> Result<SharedOnlyArgs, clap::Error> {
-        let mut argv = vec!["shared-only"];
-        argv.extend_from_slice(args);
-        SharedOnlyArgs::try_parse_from(argv)
-    }
-
-    #[test]
-    fn tui_parser_defaults_to_continuous_and_has_no_output_option() {
-        let args = parse(&["127.0.0.1:2112"]).unwrap();
-        assert_eq!(args.targets.len(), 1);
-        assert_eq!(args.targets[0].label, None);
-        assert_eq!(args.targets[0].addr, "127.0.0.1:2112");
-        assert_eq!(args.pacing, GroupPacingArg::Staggered);
-        assert_eq!(args.duration, DEFAULT_TUI_DURATION);
-        assert!(args.is_continuous());
-        assert_eq!(args.prepare().unwrap().client.duration, None);
-
-        let finite = parse(&["--duration", "30s", "127.0.0.1:2112"]).unwrap();
-        assert_eq!(finite.duration, Duration::from_secs(30));
-        assert_eq!(
-            finite.prepare().unwrap().client.duration,
-            Some(Duration::from_secs(30))
-        );
-
-        assert!(parse(&["--output", "human", "127.0.0.1:2112"]).is_err());
-        let help = TuiArgs::command().render_help().to_string();
-        assert!(!help.contains("--output"));
-    }
-
-    #[test]
-    fn multiple_positional_targets_parse() {
-        let args = parse(&["host-a:2112", "host-b:2112"]).unwrap();
-        let specs = args.prepare().unwrap().targets;
-
-        assert_eq!(specs[0].label, "host-a:2112");
-        assert_eq!(specs[0].managed.server_addr, "host-a:2112");
-        assert_eq!(specs[1].label, "host-b:2112");
-        assert_eq!(specs[1].managed.server_addr, "host-b:2112");
-    }
-
-    #[test]
-    fn repeated_labeled_targets_parse() {
-        let args = parse(&["ams=ams.example.com:2112", "sg=sg.example.com:2112"]).unwrap();
-        let specs = args.prepare().unwrap().targets;
-
-        assert_eq!(specs[0].label, "ams");
-        assert_eq!(specs[0].managed.server_addr, "ams.example.com:2112");
-        assert_eq!(specs[1].label, "sg");
-        assert_eq!(specs[1].managed.server_addr, "sg.example.com:2112");
-    }
-
-    #[test]
-    fn at_least_one_target_is_required() {
-        // The TUI has no target-free mode, so this is rejected at parse time
-        // rather than during preparation.
-        assert!(parse(&[]).is_err());
-        assert!(parse(&["ams=ams.example.com:2112"]).is_ok());
-    }
-
-    #[test]
-    fn duplicate_labels_are_rejected() {
-        let args = parse(&["host-a:2112", "host-a:2112=host-b:2112"]).unwrap();
-        let err = args.prepare().unwrap_err();
-
-        assert!(err.contains("duplicate target label"));
-    }
-
-    #[test]
-    fn duplicate_positional_target_strings_get_stable_suffixes() {
-        let args = parse(&["host-a:2112", "host-a:2112"]).unwrap();
-        let specs = args.prepare().unwrap().targets;
-
-        assert_eq!(specs[0].label, "host-a:2112");
-        assert_eq!(specs[1].label, "host-a:2112#2");
-    }
-
-    #[test]
-    fn duplicate_target_endpoints_are_allowed() {
-        let args = parse(&["127.0.0.1:2112", "127.0.0.1"]).unwrap();
-        assert_eq!(args.prepare().unwrap().target_count(), 2);
-    }
-
-    #[test]
-    fn invalid_labelled_target_syntax_is_rejected() {
-        assert!(parse(&["=127.0.0.1:2112"]).is_err());
-        assert!(parse(&["label="]).is_err());
-    }
-
-    #[test]
-    fn old_target_option_is_rejected() {
-        assert!(parse(&["--target", "eu=host.example"]).is_err());
-    }
-
-    #[test]
-    fn pacing_option_accepts_supported_values() {
-        assert_eq!(
-            parse(&["--pacing", "staggered", "127.0.0.1:2112"])
-                .unwrap()
-                .pacing,
-            GroupPacingArg::Staggered
-        );
-        assert_eq!(
-            parse(&["--pacing", "burst", "127.0.0.1:2112"])
-                .unwrap()
-                .pacing,
-            GroupPacingArg::Burst
-        );
-    }
-
-    #[test]
-    fn shared_client_options_match_tui_config_mapping() {
-        let shared = [
-            "--interval",
-            "250ms",
-            "--length",
-            "128",
-            "--hmac",
-            "secret",
-            "--clock",
-            "monotonic",
-            "--tstamp",
-            "receive",
-            "--stats",
-            "count",
-            "--sfill",
-            "abc",
-            "--dscp",
-            "46",
-            "--ttl",
-            "64",
-            "--loose",
-        ];
-        let tui_args = [
-            "--duration",
-            "30s",
-            "--interval",
-            "250ms",
-            "--length",
-            "128",
-            "--hmac",
-            "secret",
-            "--clock",
-            "monotonic",
-            "--tstamp",
-            "receive",
-            "--stats",
-            "count",
-            "--sfill",
-            "abc",
-            "--dscp",
-            "46",
-            "--ttl",
-            "64",
-            "--loose",
-            "127.0.0.1:2112",
-        ];
-        let tui = parse(&tui_args).unwrap().prepare().unwrap().client;
-        let common = parse_shared(&shared).unwrap().common;
-        let shared = common.to_client_config(Duration::from_secs(30));
-
-        assert_eq!(shared.duration, tui.duration);
-        assert_eq!(shared.interval, tui.interval);
-        assert_eq!(shared.length, tui.length);
-        assert_eq!(shared.received_stats, tui.received_stats);
-        assert_eq!(shared.stamp_at, tui.stamp_at);
-        assert_eq!(shared.clock, tui.clock);
-        assert_eq!(shared.dscp, tui.dscp);
-        assert_eq!(shared.hmac_key, tui.hmac_key);
-        assert_eq!(shared.server_fill, tui.server_fill);
-        assert_eq!(shared.negotiation_policy, tui.negotiation_policy);
-        assert_eq!(shared.socket_config.ttl, tui.socket_config.ttl);
-    }
-
-    #[test]
-    fn an_empty_hmac_key_is_rejected_via_the_shared_args() {
-        // CommonClientArgs is flattened into both the client and TUI parsers,
-        // so proving rejection once here covers both without duplicating it.
-        let err = parse(&["--hmac", "", "127.0.0.1:2112"]).unwrap_err();
-        assert!(err.to_string().contains("HMAC key must not be empty"));
-    }
-
-    #[test]
-    fn tui_help_lists_multi_target_options() {
-        let help = TuiArgs::command().render_help().to_string();
-        assert!(!help.contains("--target "));
-        assert!(help.contains("--pacing <PACING>"));
-    }
-}

crates/irtt-app/src/cmd/tui/run.rs

@@ -87,12 +87,18 @@ pub fn run_tui(
         ) {
             drop(handle.stop());
         }
+        let previous_dropped = dropped_events;
         let drain_state = drain_tui_events(
             &mut events,
             &mut state,
             &mut terminal_targets,
             &mut dropped_events,
         );
+        if dropped_events != previous_dropped {
+            // Data loss changes the meaning of displayed statistics, even while
+            // ordinary measurement refreshes are paused.
+            render_if_due(&mut terminal, &state, &mut next_render, true)?;
+        }
         match drain_state {
             ManagedDrainState::Empty => {
                 thread::sleep(managed_tui_wait_duration(&next_render, state.paused));
@@ -178,11 +184,16 @@ fn drain_tui_events(
     terminal_targets: &mut HashSet<TargetInstance>,
     dropped_events: &mut u64,
 ) -> ManagedDrainState {
-    drain_managed_events(events, dropped_events, |event| {
+    let previous_dropped = *dropped_events;
+    let drained = drain_managed_events(events, dropped_events, |event| {
         process_tui_event(event, state, terminal_targets);
         Ok::<(), std::convert::Infallible>(())
     })
-    .expect("processing TUI managed events is infallible")
+    .expect("processing TUI managed events is infallible");
+    if *dropped_events != previous_dropped {
+        state.mark_dropped_managed_events(*dropped_events);
+    }
+    drained
 }
 
 fn drain_final_tui_events(
@@ -301,3 +312,45 @@ fn managed_tui_wait_duration(next_render: &Instant, paused: bool) -> Duration {
     };
     render_wait.min(TUI_WAIT_SLICE)
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use ratatui::{backend::TestBackend, Terminal};
+
+    #[test]
+    fn subscription_lag_keeps_incomplete_statistics_visible_while_paused() {
+        for paused in [false, true] {
+            // The production subscription is a broadcast receiver. Overflow the
+            // real channel rather than synthesizing a lag result or UI state.
+            let (sender, mut events) = tokio::sync::broadcast::channel(1);
+            sender.send(ManagedEvent::Started).unwrap();
+            sender.send(ManagedEvent::Started).unwrap();
+            let mut state = TuiState::default();
+            if paused {
+                state.toggle_pause();
+            }
+            let mut dropped = 0;
+            let mut terminal_targets = HashSet::new();
+            drain_tui_events(&mut events, &mut state, &mut terminal_targets, &mut dropped);
+            assert_eq!(dropped, 1);
+            let mut terminal = Terminal::new(TestBackend::new(200, 40)).unwrap();
+            for _ in 0..2 {
+                // Empty drains must not clear the warning on later redraws.
+                drain_tui_events(&mut events, &mut state, &mut terminal_targets, &mut dropped);
+                terminal
+                    .draw(|frame| super::super::ui::draw_dashboard(frame, &state))
+                    .unwrap();
+                let text = terminal
+                    .backend()
+                    .buffer()
+                    .content()
+                    .iter()
+                    .map(|cell| cell.symbol())
+                    .collect::<String>();
+                assert!(text.contains("incomplete:dropped=1"));
+                assert_eq!(text.contains("display paused"), paused);
+            }
+        }
+    }
+}

crates/irtt-app/src/shared/client/mod.rs

@@ -9,9 +9,12 @@ pub use args::{
     ClockArg, CommonClientArgs, ReceivedStatsArg, TimestampArg,
 };
 pub use config::{expected_probe_count, DEFAULT_RECV_TIMEOUT};
-pub use prepare::{prepare_managed_run, ManagedRunSetup, TargetSelection, MANAGED_EVENT_CAPACITY};
+pub use prepare::{
+    prepare_managed_run, ManagedRunSetup, TargetSelection, MANAGED_EVENT_CAPACITY,
+    STDIN_MAX_DESIRED_TARGETS, STDIN_MAX_LIVE_TARGET_GENERATIONS, STDIN_OUTCOME_HISTORY_LIMIT,
+};
 pub use session::is_shutdown_requested;
 pub use targets::{
-    parse_target, prepare_managed_targets, target_specs, GroupPacingArg, PreparedTarget, TargetArg,
-    TargetSpec,
+    parse_stdin_target_set, parse_target, prepare_managed_targets, target_specs, GroupPacingArg,
+    PreparedTarget, TargetArg, TargetSpec,
 };

crates/irtt-app/src/shared/client/prepare.rs

@@ -22,6 +22,9 @@ use super::{
 
 /// Capacity of the lossy managed presentation event channel.
 pub const MANAGED_EVENT_CAPACITY: usize = 16_384;
+pub const STDIN_MAX_DESIRED_TARGETS: usize = 128;
+pub const STDIN_MAX_LIVE_TARGET_GENERATIONS: usize = 256;
+pub const STDIN_OUTCOME_HISTORY_LIMIT: usize = 256;
 
 /// Target and pacing arguments common to the client applets.
 ///
@@ -31,6 +34,7 @@ pub const MANAGED_EVENT_CAPACITY: usize = 16_384;
 pub struct TargetSelection<'a> {
     pub targets: &'a [TargetArg],
     pub pacing: GroupPacingArg,
+    pub stdin_controlled: bool,
 }
 
 /// Everything a managed run needs, prepared and validated together.
@@ -46,6 +50,8 @@ pub struct ManagedRunSetup {
     pub client: ClientConfig,
     /// Send coordination across active targets.
     pub pacing: ManagedPacing,
+    /// Whether this stream may replace its desired set from stdin.
+    pub stdin_controlled: bool,
 }
 
 impl ManagedRunSetup {
@@ -70,7 +76,7 @@ impl ManagedRunSetup {
     /// Managed driver configuration for this run.
     pub fn managed_config(&self) -> ManagedClientConfig {
         let target_count = self.target_count();
-        ManagedClientConfig {
+        let mut config = ManagedClientConfig {
             client: self.client.clone(),
             pacing: self.pacing,
             completion: ManagedCompletionPolicy::FinishWhenQuiescent,
@@ -78,7 +84,13 @@ impl ManagedRunSetup {
             outcome_history_limit: target_count,
             max_live_target_generations: target_count,
             ..ManagedClientConfig::default()
+        };
+        if self.stdin_controlled {
+            config.completion = ManagedCompletionPolicy::ExplicitStop;
+            config.outcome_history_limit = STDIN_OUTCOME_HISTORY_LIMIT;
+            config.max_live_target_generations = STDIN_MAX_LIVE_TARGET_GENERATIONS;
         }
+        config
     }
 }
 
@@ -91,161 +103,21 @@ pub fn prepare_managed_run(
     duration: Duration,
     selection: TargetSelection<'_>,
 ) -> Result<ManagedRunSetup, String> {
-    let specs = target_specs(selection.targets)?;
+    let specs = if selection.stdin_controlled {
+        if selection.targets.len() > STDIN_MAX_DESIRED_TARGETS {
+            return Err(format!(
+                "initial target set exceeds the {STDIN_MAX_DESIRED_TARGETS}-target limit"
+            ));
+        }
+        super::targets::target_specs_with_empty(selection.targets, true)?
+    } else {
+        target_specs(selection.targets)?
+    };
     let targets = prepare_managed_targets(specs)?;
     Ok(ManagedRunSetup {
         targets,
         client: common.to_client_config(duration),
         pacing: selection.pacing.into(),
+        stdin_controlled: selection.stdin_controlled,
     })
 }
-
-#[cfg(test)]
-mod tests {
-    use clap::Parser;
-
-    use super::*;
-
-    #[derive(Parser)]
-    struct CommonOnlyArgs {
-        #[command(flatten)]
-        common: CommonClientArgs,
-    }
-
-    fn common(args: &[&str]) -> CommonClientArgs {
-        let mut argv = vec!["common-only"];
-        argv.extend_from_slice(args);
-        CommonOnlyArgs::try_parse_from(argv).unwrap().common
-    }
-
-    fn unlabeled(addr: &str) -> TargetArg {
-        TargetArg {
-            label: None,
-            addr: addr.to_owned(),
-        }
-    }
-
-    fn labeled(label: &str, addr: &str) -> TargetArg {
-        TargetArg {
-            label: Some(label.to_owned()),
-            addr: addr.to_owned(),
-        }
-    }
-
-    fn prepare(
-        targets: &[TargetArg],
-        pacing: GroupPacingArg,
-        duration: Duration,
-    ) -> Result<ManagedRunSetup, String> {
-        prepare_managed_run(&common(&[]), duration, TargetSelection { targets, pacing })
-    }
-
-    #[test]
-    fn a_single_target_prepares_one_managed_target_and_a_finite_duration() {
-        let setup = prepare(
-            &[unlabeled("127.0.0.1:2112")],
-            GroupPacingArg::Staggered,
-            Duration::from_secs(30),
-        )
-        .unwrap();
-
-        assert_eq!(setup.target_count(), 1);
-        assert!(!setup.is_multi_target());
-        assert_eq!(setup.targets[0].label, "127.0.0.1:2112");
-        assert_eq!(setup.targets[0].managed.server_addr, "127.0.0.1:2112");
-        assert_eq!(setup.client.duration, Some(Duration::from_secs(30)));
-        assert_eq!(setup.pacing, ManagedPacing::Staggered);
-    }
-
-    #[test]
-    fn a_zero_duration_prepares_a_continuous_client_config() {
-        let setup = prepare(
-            &[unlabeled("127.0.0.1:2112")],
-            GroupPacingArg::Staggered,
-            Duration::ZERO,
-        )
-        .unwrap();
-
-        assert_eq!(setup.client.duration, None);
-    }
-
-    #[test]
-    fn multiple_targets_keep_argument_order_and_share_one_client_config() {
-        let setup = prepare(
-            &[
-                unlabeled("host-a:2112"),
-                unlabeled("host-b:2112"),
-                labeled("sg", "sg.example.test:2112"),
-            ],
-            GroupPacingArg::Burst,
-            Duration::from_secs(10),
-        )
-        .unwrap();
-
-        assert!(setup.is_multi_target());
-        let labels: Vec<_> = setup
-            .targets
-            .iter()
-            .map(|target| target.label.as_str())
-            .collect();
-        assert_eq!(labels, ["host-a:2112", "host-b:2112", "sg"]);
-        assert_eq!(setup.targets[2].managed.server_addr, "sg.example.test:2112");
-        assert_eq!(setup.pacing, ManagedPacing::Burst);
-
-        let config = setup.managed_config();
-        assert_eq!(config.outcome_history_limit, 3);
-        assert_eq!(config.max_live_target_generations, 3);
-        assert_eq!(config.event_capacity, MANAGED_EVENT_CAPACITY);
-        assert_eq!(config.pacing, ManagedPacing::Burst);
-        assert_eq!(config.client, setup.client);
-        assert_eq!(setup.managed_targets().len(), 3);
-    }
-
-    #[test]
-    fn the_shared_client_config_carries_no_target_of_its_own() {
-        // The managed driver replaces the address, and the CLI's key, per
-        // target, so the template must not pin either to one target.
-        let targets = vec![unlabeled("host-a:2112"), unlabeled("host-b:2112")];
-        let setup = prepare_managed_run(
-            &common(&["--hmac", "secret"]),
-            Duration::from_secs(10),
-            TargetSelection {
-                targets: &targets,
-                pacing: GroupPacingArg::Staggered,
-            },
-        )
-        .unwrap();
-
-        assert_eq!(
-            setup.client.server_addr,
-            ClientConfig::default().server_addr
-        );
-        assert_eq!(setup.client.hmac_key, Some(b"secret".to_vec()));
-        // Per-target authentication is not exposed on the command line, so no
-        // target carries an override of the shared key.
-        assert!(setup
-            .targets
-            .iter()
-            .all(|target| target.managed.auth.is_none()));
-    }
-
-    #[test]
-    fn an_empty_target_set_is_rejected_with_the_list_columns_hint() {
-        let err = prepare(&[], GroupPacingArg::Staggered, Duration::from_secs(10)).unwrap_err();
-
-        assert!(err.contains("at least one target is required"));
-        assert!(err.contains("--list-columns"));
-    }
-
-    #[test]
-    fn a_duplicate_label_is_rejected_before_any_configuration_is_built() {
-        let targets = vec![
-            unlabeled("host-a:2112"),
-            labeled("host-a:2112", "host-b:2112"),
-        ];
-        let err =
-            prepare(&targets, GroupPacingArg::Staggered, Duration::from_secs(10)).unwrap_err();
-
-        assert!(err.contains("duplicate target label"));
-    }
-}

crates/irtt-app/src/shared/client/session.rs

@@ -81,61 +81,3 @@ pub fn request_managed_stop_once(stop_requested: &mut bool) -> bool {
     *stop_requested = true;
     true
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn peer_close_run_error_is_run_mode_and_interruption_aware() {
-        assert_eq!(peer_close_run_error(false, false, 1), None);
-        assert_eq!(peer_close_run_error(true, false, 0), None);
-        assert_eq!(peer_close_run_error(true, true, 1), None);
-        assert_eq!(
-            peer_close_run_error(true, false, 1).as_deref(),
-            Some("continuous run ended because of peer closure (1 target session)")
-        );
-        assert_eq!(
-            peer_close_run_error(true, false, 3).as_deref(),
-            Some("continuous run ended because of peer closure (3 target sessions)")
-        );
-    }
-
-    #[test]
-    fn grouped_peer_close_stop_policy_is_run_mode_and_one_shot() {
-        let mut stop_requested = false;
-        assert!(!request_managed_stop_for_peer_close(
-            false,
-            false,
-            1,
-            &mut stop_requested,
-        ));
-        assert!(!request_managed_stop_for_peer_close(
-            true,
-            true,
-            1,
-            &mut stop_requested,
-        ));
-        assert!(!request_managed_stop_for_peer_close(
-            true,
-            false,
-            0,
-            &mut stop_requested,
-        ));
-        assert!(!stop_requested);
-
-        assert!(request_managed_stop_for_peer_close(
-            true,
-            false,
-            1,
-            &mut stop_requested,
-        ));
-        assert!(stop_requested);
-        assert!(!request_managed_stop_for_peer_close(
-            true,
-            false,
-            1,
-            &mut stop_requested,
-        ));
-    }
-}

crates/irtt-app/src/shared/client/targets.rs

@@ -1,26 +1,99 @@
-use std::collections::HashSet;
+use std::{collections::HashSet, fmt};
 
 use clap::ValueEnum;
-use irtt_client::managed::{ManagedPacing, ManagedTargetConfig, TargetId};
+use irtt_client::{
+    managed::{ManagedPacing, ManagedTargetConfig, TargetId},
+    ClientAuthConfig,
+};
 
-#[derive(Debug, Clone, PartialEq, Eq)]
+/// One raw positional target captured by Clap.
+///
+/// Parsing happens during run preparation so invalid target syntax never makes
+/// Clap include the original argument (which may carry an HMAC key) in an
+/// error diagnostic.
+#[derive(Clone, PartialEq, Eq)]
 pub struct TargetArg {
-    pub label: Option<String>,
-    pub addr: String,
+    input: String,
 }
 
-#[derive(Debug, Clone, PartialEq, Eq)]
+impl TargetArg {
+    pub fn new(input: impl Into<String>) -> Self {
+        Self {
+            input: input.into(),
+        }
+    }
+}
+
+impl fmt::Debug for TargetArg {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str("TargetArg(<redacted>)")
+    }
+}
+
+/// Capture one positional target without exposing it through Clap diagnostics.
+pub fn parse_target(input: &str) -> Result<TargetArg, String> {
+    Ok(TargetArg::new(input))
+}
+
+#[derive(Clone, PartialEq, Eq)]
+pub enum TargetAuth {
+    Inherit,
+    Override(Vec<u8>),
+    Disable,
+}
+
+impl fmt::Debug for TargetAuth {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::Inherit => f.write_str("Inherit"),
+            Self::Override(_) => f.write_str("Override(<redacted>)"),
+            Self::Disable => f.write_str("Disable"),
+        }
+    }
+}
+
+#[derive(Clone, PartialEq, Eq)]
 pub struct TargetSpec {
     pub label: String,
     pub addr: String,
+    pub auth: TargetAuth,
 }
 
-#[derive(Debug, Clone)]
+impl fmt::Debug for TargetSpec {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("TargetSpec")
+            .field("label", &self.label)
+            .field("addr", &self.addr)
+            .field("auth", &self.auth)
+            .finish()
+    }
+}
+
+#[derive(Clone)]
 pub struct PreparedTarget {
     pub label: String,
     pub managed: ManagedTargetConfig,
 }
 
+impl fmt::Debug for PreparedTarget {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("PreparedTarget")
+            .field("label", &self.label)
+            .field("server_addr", &self.managed.server_addr)
+            .field(
+                "auth",
+                &match &self.managed.auth {
+                    None => TargetAuth::Inherit,
+                    Some(ClientAuthConfig { hmac_key: Some(_) }) => {
+                        TargetAuth::Override(Vec::new())
+                    }
+                    Some(ClientAuthConfig { hmac_key: None }) => TargetAuth::Disable,
+                },
+            )
+            .finish()
+    }
+}
+
 #[derive(Debug, Clone, Copy, PartialEq, Eq, ValueEnum)]
 pub enum GroupPacingArg {
     Staggered,
@@ -36,191 +109,216 @@ impl From<GroupPacingArg> for ManagedPacing {
     }
 }
 
-/// Parse one positional target argument, as `TARGET` or `LABEL=TARGET`.
-pub fn parse_target(input: &str) -> Result<TargetArg, String> {
-    match input.split_once('=') {
-        None => Ok(TargetArg {
-            label: None,
-            addr: input.to_owned(),
-        }),
-        Some((label, addr)) => {
-            if label.is_empty() {
-                return Err("target label must not be empty".to_owned());
-            }
-            if addr.is_empty() {
-                return Err("target address must not be empty".to_owned());
-            }
-            Ok(TargetArg {
-                label: Some(label.to_owned()),
-                addr: addr.to_owned(),
-            })
-        }
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+enum TargetParseError {
+    EmptyLabel,
+    EmptyAddress,
+    InvalidEscape,
+    EmptyTarget,
+}
+
+impl fmt::Display for TargetParseError {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let message = match self {
+            Self::EmptyLabel => "target label must not be empty",
+            Self::EmptyAddress => "target address must not be empty",
+            Self::InvalidEscape => "invalid target escape sequence",
+            Self::EmptyTarget => "target must not be empty",
+        };
+        f.write_str(message)
     }
 }
 
-pub fn target_specs(targets: &[TargetArg]) -> Result<Vec<TargetSpec>, String> {
+fn split_unescaped(input: &str, delimiter: char) -> Result<Vec<&str>, TargetParseError> {
+    let mut parts = Vec::new();
+    let mut start = 0;
+    let mut escaped = false;
+    for (index, ch) in input.char_indices() {
+        if escaped {
+            escaped = false;
+        } else if ch == '\\' {
+            escaped = true;
+        } else if ch == delimiter {
+            parts.push(&input[start..index]);
+            start = index + ch.len_utf8();
+        }
+    }
+    if escaped {
+        return Err(TargetParseError::InvalidEscape);
+    }
+    parts.push(&input[start..]);
+    Ok(parts)
+}
+
+fn first_unescaped(input: &str, delimiter: char) -> Result<Option<usize>, TargetParseError> {
+    let mut escaped = false;
+    for (index, ch) in input.char_indices() {
+        if escaped {
+            escaped = false;
+        } else if ch == '\\' {
+            escaped = true;
+        } else if ch == delimiter {
+            return Ok(Some(index));
+        }
+    }
+    if escaped {
+        return Err(TargetParseError::InvalidEscape);
+    }
+    Ok(None)
+}
+
+fn unescape(input: &str) -> Result<String, TargetParseError> {
+    let mut output = String::with_capacity(input.len());
+    let mut escaped = false;
+    for ch in input.chars() {
+        if escaped {
+            if !matches!(ch, '\\' | '=' | ';' | ',' | '@') {
+                return Err(TargetParseError::InvalidEscape);
+            }
+            output.push(ch);
+            escaped = false;
+        } else if ch == '\\' {
+            escaped = true;
+        } else {
+            output.push(ch);
+        }
+    }
+    if escaped {
+        return Err(TargetParseError::InvalidEscape);
+    }
+    Ok(output)
+}
+
+fn hmac_modifier(input: &str) -> Result<Option<usize>, TargetParseError> {
+    let mut escaped = false;
+    for (index, ch) in input.char_indices() {
+        if escaped {
+            escaped = false;
+        } else if ch == '\\' {
+            escaped = true;
+        } else if input[index..].starts_with("@hmac=") {
+            return Ok(Some(index));
+        }
+    }
+    if escaped {
+        return Err(TargetParseError::InvalidEscape);
+    }
+    Ok(None)
+}
+
+fn parse_target_syntax(
+    input: &str,
+) -> Result<(Option<String>, String, TargetAuth), TargetParseError> {
+    if input.is_empty() {
+        return Err(TargetParseError::EmptyTarget);
+    }
+    let (main, auth) = match hmac_modifier(input)? {
+        Some(index) => {
+            let value = unescape(&input[index + "@hmac=".len()..])?;
+            let auth = if value.is_empty() {
+                TargetAuth::Disable
+            } else {
+                TargetAuth::Override(value.into_bytes())
+            };
+            (&input[..index], auth)
+        }
+        None => (input, TargetAuth::Inherit),
+    };
+    let (label, address) = match first_unescaped(main, '=')? {
+        None => (None, unescape(main)?),
+        Some(index) => {
+            let label = unescape(&main[..index])?;
+            let address = unescape(&main[index + '='.len_utf8()..])?;
+            (Some(label), address)
+        }
+    };
+    if label.as_deref().is_some_and(str::is_empty) {
+        return Err(TargetParseError::EmptyLabel);
+    }
+    if address.is_empty() {
+        return Err(TargetParseError::EmptyAddress);
+    }
+    Ok((label, address, auth))
+}
+
+pub(crate) fn target_specs_with_empty(
+    targets: &[TargetArg],
+    allow_empty: bool,
+) -> Result<Vec<TargetSpec>, String> {
     let mut specs = Vec::with_capacity(targets.len());
-    let mut unlabeled_counts = std::collections::HashMap::<&str, usize>::new();
-    for target in targets {
-        let label = match &target.label {
-            Some(label) => label.clone(),
+    let mut unlabeled_counts = std::collections::HashMap::<String, usize>::new();
+    for (index, target) in targets.iter().enumerate() {
+        let (explicit_label, addr, auth) = parse_target_syntax(&target.input)
+            .map_err(|error| format!("invalid target {}: {error}", index + 1))?;
+        let label = match explicit_label {
+            Some(label) => label,
             None => {
-                let count = unlabeled_counts.entry(target.addr.as_str()).or_default();
+                let count = unlabeled_counts.entry(addr.clone()).or_default();
                 *count += 1;
                 if *count == 1 {
-                    target.addr.clone()
+                    addr.clone()
                 } else {
-                    format!("{}#{}", target.addr, *count)
+                    format!("{}#{}", addr, *count)
                 }
             }
         };
-        specs.push(TargetSpec {
-            label,
-            addr: target.addr.clone(),
-        });
+        specs.push(TargetSpec { label, addr, auth });
     }
 
-    if specs.is_empty() {
+    if specs.is_empty() && !allow_empty {
         return Err("at least one target is required unless --list-columns is set".to_owned());
     }
 
     let mut labels = HashSet::new();
     for spec in &specs {
         if !labels.insert(spec.label.clone()) {
-            return Err(format!("duplicate target label {:?}", spec.label));
+            return Err("duplicate target label".to_owned());
         }
     }
 
     Ok(specs)
 }
 
+pub fn target_specs(targets: &[TargetArg]) -> Result<Vec<TargetSpec>, String> {
+    target_specs_with_empty(targets, false)
+}
+
 pub fn prepare_managed_targets(specs: Vec<TargetSpec>) -> Result<Vec<PreparedTarget>, String> {
     let mut targets = Vec::with_capacity(specs.len());
     for spec in specs {
+        let mut managed = ManagedTargetConfig::new(TargetId::from(spec.label.clone()), spec.addr);
+        managed.auth = match spec.auth {
+            TargetAuth::Inherit => None,
+            TargetAuth::Override(hmac_key) => Some(ClientAuthConfig {
+                hmac_key: Some(hmac_key),
+            }),
+            TargetAuth::Disable => Some(ClientAuthConfig { hmac_key: None }),
+        };
         targets.push(PreparedTarget {
-            label: spec.label.clone(),
-            managed: ManagedTargetConfig::new(TargetId::from(spec.label), spec.addr),
+            label: spec.label,
+            managed,
         });
     }
     Ok(targets)
 }
 
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    fn unlabeled(addr: &str) -> TargetArg {
-        TargetArg {
-            label: None,
-            addr: addr.to_owned(),
-        }
+/// Parse one complete stdin target set after its line terminator was removed.
+///
+/// Commas frame stdin elements only; positional target arguments do not use
+/// this framing and may therefore contain raw commas.
+pub fn parse_stdin_target_set(
+    record: &str,
+    maximum_targets: usize,
+) -> Result<Vec<PreparedTarget>, String> {
+    if record == "[]" {
+        return Ok(Vec::new());
     }
-
-    fn labeled(label: &str, addr: &str) -> TargetArg {
-        TargetArg {
-            label: Some(label.to_owned()),
-            addr: addr.to_owned(),
-        }
-    }
-
-    #[test]
-    fn parse_target_without_equals_is_unlabeled() {
-        let target = parse_target("host.example").unwrap();
-        assert_eq!(target.label, None);
-        assert_eq!(target.addr, "host.example");
-
-        let target = parse_target("host.example:2112").unwrap();
-        assert_eq!(target.label, None);
-        assert_eq!(target.addr, "host.example:2112");
-
-        let target = parse_target("[::1]:2112").unwrap();
-        assert_eq!(target.label, None);
-        assert_eq!(target.addr, "[::1]:2112");
-    }
-
-    #[test]
-    fn parse_target_with_equals_splits_on_first() {
-        let target = parse_target("eu=host.example").unwrap();
-        assert_eq!(target.label, Some("eu".to_owned()));
-        assert_eq!(target.addr, "host.example");
-
-        let target = parse_target("eu=host.example:2112").unwrap();
-        assert_eq!(target.label, Some("eu".to_owned()));
-        assert_eq!(target.addr, "host.example:2112");
-    }
-
-    #[test]
-    fn parse_target_rejects_empty_label_or_address() {
-        assert!(parse_target("=host.example").is_err());
-        assert!(parse_target("eu=").is_err());
-    }
-
-    #[test]
-    fn target_specs_suffix_repeated_unlabeled_and_reject_duplicate_labels() {
-        let targets = vec![unlabeled("host-a:2112"), unlabeled("host-a:2112")];
-        let specs = target_specs(&targets).unwrap();
-
-        assert_eq!(specs[0].label, "host-a:2112");
-        assert_eq!(specs[1].label, "host-a:2112#2");
-
-        let targets = vec![
-            unlabeled("host-a:2112"),
-            labeled("host-a:2112", "host-b:2112"),
-        ];
-        let err = target_specs(&targets).unwrap_err();
-        assert!(err.contains("duplicate target label"));
-    }
-
-    #[test]
-    fn target_specs_preserve_argument_order_with_mixed_labels() {
-        let targets = vec![
-            unlabeled("local"),
-            labeled("eu", "eu.example"),
-            unlabeled("backup"),
-            labeled("us", "us.example"),
-        ];
-        let specs = target_specs(&targets).unwrap();
-
-        let labels: Vec<_> = specs.iter().map(|spec| spec.label.as_str()).collect();
-        assert_eq!(labels, ["local", "eu", "backup", "us"]);
-        let addrs: Vec<_> = specs.iter().map(|spec| spec.addr.as_str()).collect();
-        assert_eq!(addrs, ["local", "eu.example", "backup", "us.example"]);
-    }
-
-    #[test]
-    fn target_specs_count_unlabeled_occurrences_independently_of_explicit_labels() {
-        let targets = vec![unlabeled("foo"), labeled("eu", "foo"), unlabeled("foo")];
-        let specs = target_specs(&targets).unwrap();
-
-        let labels: Vec<_> = specs.iter().map(|spec| spec.label.as_str()).collect();
-        assert_eq!(labels, ["foo", "eu", "foo#2"]);
-    }
-
-    #[test]
-    fn target_specs_reject_generated_suffix_collisions() {
-        let targets = vec![
-            unlabeled("host.example"),
-            unlabeled("host.example"),
-            labeled("host.example#2", "other.example"),
-        ];
-        let err = target_specs(&targets).unwrap_err();
-        assert!(err.contains("duplicate target label"));
-    }
-
-    #[test]
-    fn target_preparation_preserves_hostname_and_allows_duplicate_endpoints() {
-        let specs = vec![
-            TargetSpec {
-                label: "a".to_owned(),
-                addr: "example.test".to_owned(),
-            },
-            TargetSpec {
-                label: "b".to_owned(),
-                addr: "example.test".to_owned(),
-            },
-        ];
-        let targets = prepare_managed_targets(specs).unwrap();
-        assert_eq!(targets[0].managed.server_addr, "example.test");
-        assert_eq!(targets[1].managed.server_addr, "example.test");
+    let elements = split_unescaped(record, ',').map_err(|error| error.to_string())?;
+    if elements.len() > maximum_targets {
+        return Err(format!(
+            "target set exceeds the {maximum_targets}-target limit"
+        ));
     }
+    let args = elements.into_iter().map(TargetArg::new).collect::<Vec<_>>();
+    prepare_managed_targets(target_specs_with_empty(&args, true)?)
 }

crates/irtt-app/tests/cli.rs

@@ -0,0 +1,479 @@
+#[cfg(feature = "client")]
+#[path = "support/in_tree_server.rs"]
+mod in_tree_server;
+
+#[cfg(feature = "client")]
+use irtt_server::ServerConfig;
+use std::process::Command;
+
+#[cfg(feature = "client")]
+struct ClientProcess(std::process::Child);
+
+#[cfg(feature = "client")]
+impl Drop for ClientProcess {
+    fn drop(&mut self) {
+        let _ = self.0.kill();
+        let _ = self.0.wait();
+    }
+}
+
+#[cfg(feature = "client")]
+impl ClientProcess {
+    fn wait(&mut self) -> std::process::ExitStatus {
+        let deadline = std::time::Instant::now() + std::time::Duration::from_secs(5);
+        loop {
+            if let Some(status) = self.0.try_wait().unwrap() {
+                return status;
+            }
+            assert!(
+                std::time::Instant::now() < deadline,
+                "client did not terminate within five seconds"
+            );
+            std::thread::sleep(std::time::Duration::from_millis(10));
+        }
+    }
+}
+
+// Dispatch/help/availability belong to the application and run in every build.
+#[test]
+fn dispatcher_reports_and_runs_the_enabled_applets() {
+    let dispatcher = env!("CARGO_BIN_EXE_irtt-rs");
+    let help = Command::new(dispatcher).arg("--help").output().unwrap();
+    assert!(help.status.success());
+    let help = String::from_utf8(help.stdout).unwrap();
+    for (applet, enabled) in [
+        ("client", cfg!(feature = "client")),
+        ("server", cfg!(feature = "server")),
+        ("tui", cfg!(feature = "tui")),
+    ] {
+        let row = help
+            .lines()
+            .find(|line| line.trim_start().starts_with(applet))
+            .unwrap();
+        assert_eq!(row.contains("not available"), !enabled);
+        let output = Command::new(dispatcher)
+            .args([applet, "--help"])
+            .output()
+            .unwrap();
+        assert_eq!(output.status.success(), enabled, "{applet}");
+        if !enabled {
+            assert!(String::from_utf8(output.stderr)
+                .unwrap()
+                .contains("not available"));
+        }
+    }
+    let binaries = [
+        dispatcher,
+        #[cfg(feature = "client")]
+        env!("CARGO_BIN_EXE_irtt-client"),
+        #[cfg(feature = "server")]
+        env!("CARGO_BIN_EXE_irtt-server"),
+        #[cfg(feature = "tui")]
+        env!("CARGO_BIN_EXE_irtt-tui"),
+    ];
+    for binary in binaries {
+        assert!(Command::new(binary)
+            .arg("--help")
+            .output()
+            .unwrap()
+            .status
+            .success());
+        assert!(!Command::new(binary)
+            .arg("--invalid-option")
+            .output()
+            .unwrap()
+            .status
+            .success());
+    }
+}
+
+// The default presentation must reach a meaningful packet summary for a finite run.
+#[cfg(feature = "client")]
+#[test]
+fn default_client_output_emits_a_packet_summary() {
+    use std::{io::Read, process::Stdio, thread};
+    let server = in_tree_server::InTreeServer::start(ServerConfig::default());
+    let mut client = ClientProcess(
+        Command::new(env!("CARGO_BIN_EXE_irtt-client"))
+            .env_clear()
+            .args([
+                "--duration",
+                "100ms",
+                "--interval",
+                "20ms",
+                &server.addr.to_string(),
+            ])
+            .stdin(Stdio::null())
+            .stdout(Stdio::piped())
+            .stderr(Stdio::piped())
+            .spawn()
+            .unwrap(),
+    );
+    let mut stdout = client.0.stdout.take().unwrap();
+    let stdout = thread::spawn(move || {
+        let mut text = String::new();
+        stdout.read_to_string(&mut text).unwrap();
+        text
+    });
+    let mut stderr = client.0.stderr.take().unwrap();
+    let stderr = thread::spawn(move || {
+        let mut text = String::new();
+        stderr.read_to_string(&mut text).unwrap();
+        text
+    });
+    let status = client.wait();
+    let stdout = stdout.join().unwrap();
+    let stderr = stderr.join().unwrap();
+    assert!(status.success(), "{stderr}");
+    assert!(stdout.contains("irtt-rs summary"), "{stdout}");
+    let packets = stdout
+        .lines()
+        .find(|line| line.starts_with("packets:"))
+        .expect("default output must include the packet summary");
+    for field in ["sent=", "received="] {
+        let count = packets
+            .split_whitespace()
+            .find_map(|word| word.strip_prefix(field))
+            .unwrap()
+            .parse::<u64>()
+            .unwrap();
+        assert!(
+            count > 0,
+            "summary must report {field} a positive count: {packets}"
+        );
+    }
+}
+
+#[cfg(feature = "client")]
+#[test]
+fn target_authentication_inherits_overrides_or_disables_the_global_key() {
+    use clap::Parser;
+    use irtt_app::cmd::client::args::ClientArgs;
+    let args = ClientArgs::try_parse_from([
+        "irtt-client",
+        "--hmac",
+        "global-test-key",
+        "inherit=127.0.0.1:2112",
+        "override=127.0.0.1:2113@hmac=target-test-key",
+        "disable=127.0.0.1:2114@hmac=",
+    ])
+    .unwrap();
+    let setup = args.prepare().unwrap();
+    assert_eq!(
+        setup.managed_config().client.hmac_key.as_deref(),
+        Some(b"global-test-key".as_slice())
+    );
+    let targets = setup.managed_targets();
+    let authentication: Vec<_> = targets
+        .iter()
+        .map(|target| target.auth.as_ref().map(|auth| auth.hmac_key.as_deref()))
+        .collect();
+    assert_eq!(
+        authentication,
+        [None, Some(Some(b"target-test-key".as_slice())), Some(None)]
+    );
+}
+
+// A real authenticated server detects broken client argument-to-config mapping.
+#[cfg(feature = "client")]
+#[test]
+fn client_arguments_export_a_real_client_run() {
+    use std::{io::Read, process::Stdio, thread};
+    let dispatcher = env!("CARGO_BIN_EXE_irtt-rs");
+    for option in ["--dscp", "--ttl"] {
+        assert!(!Command::new(dispatcher)
+            .args(["client", option, "256", "127.0.0.1:9"])
+            .output()
+            .unwrap()
+            .status
+            .success());
+    }
+    let server =
+        in_tree_server::InTreeServer::start(ServerConfig::default().with_hmac_key(b"cli-test"));
+    let mut client = ClientProcess(
+        Command::new(dispatcher)
+            .args([
+                "client",
+                "--duration",
+                "100ms",
+                "--interval",
+                "20ms",
+                "--hmac",
+                "cli-test",
+                "--length",
+                "128",
+                "--sfill",
+                "pattern:ab",
+                "--clock",
+                "wall",
+                "--tstamp",
+                "both",
+                "--stats",
+                "both",
+                "--ttl",
+                "64",
+                "--format",
+                "jsonl",
+                "--columns",
+                "target,event,bytes",
+                &format!("edge={}", server.addr),
+            ])
+            .stdin(Stdio::null())
+            .stdout(Stdio::piped())
+            .stderr(Stdio::piped())
+            .spawn()
+            .unwrap(),
+    );
+    // Drain both pipes while waiting so output cannot block client termination.
+    let mut stdout = client.0.stdout.take().unwrap();
+    let stdout = thread::spawn(move || {
+        let mut bytes = Vec::new();
+        stdout.read_to_end(&mut bytes).unwrap();
+        bytes
+    });
+    let mut stderr = client.0.stderr.take().unwrap();
+    let stderr = thread::spawn(move || {
+        let mut bytes = Vec::new();
+        stderr.read_to_end(&mut bytes).unwrap();
+        bytes
+    });
+    let status = client.wait();
+    let stdout = stdout.join().unwrap();
+    let stderr = stderr.join().unwrap();
+    assert!(status.success(), "{}", String::from_utf8_lossy(&stderr));
+    let stdout = String::from_utf8(stdout).unwrap();
+    let rows: Vec<_> = stdout.lines().collect();
+    assert!(!rows.is_empty());
+    assert!(rows.iter().all(|row| row.starts_with('{')
+        && row.ends_with('}')
+        && row.contains("\"target\":\"edge\"")));
+    assert!(rows
+        .iter()
+        .any(|row| row.contains("\"event\":\"echo_reply\"") && row.contains("\"bytes\":128")));
+    assert!(rows
+        .iter()
+        .any(|row| row.contains("\"event\":\"session_closed\"")));
+}
+
+#[cfg(any(feature = "client", feature = "tui"))]
+#[test]
+fn malformed_target_diagnostics_do_not_expose_authentication_keys() {
+    let secret = "malformed-target-secret-92817";
+    for applet in [
+        #[cfg(feature = "client")]
+        "client",
+        #[cfg(feature = "tui")]
+        "tui",
+    ] {
+        let output = Command::new(env!("CARGO_BIN_EXE_irtt-rs"))
+            .args([applet, &format!(r"edge=127.0.0.1:9@hmac={secret}\q")])
+            .output()
+            .unwrap();
+        assert!(!output.status.success());
+        let stderr = String::from_utf8(output.stderr).unwrap();
+        assert!(
+            !stderr.trim().is_empty(),
+            "malformed target must report a diagnostic"
+        );
+        assert!(!stderr.contains(secret), "target authentication key leaked");
+        assert!(!String::from_utf8_lossy(&output.stdout).contains(secret));
+    }
+}
+
+#[cfg(feature = "server")]
+#[test]
+fn server_arguments_resolve_binds_and_map_policy() {
+    use clap::{CommandFactory, FromArgMatches, Parser};
+    use irtt_app::cmd::server::ServerArgs;
+    use irtt_server::TimestampAllowance;
+    use std::time::Duration;
+    // Isolate zero-argument defaults from the test runner's environment without
+    // mutating process-global environment in this parallel test process.
+    let defaults = ServerArgs::from_arg_matches(
+        &ServerArgs::command()
+            .mut_args(|arg| arg.env(None::<&str>))
+            .try_get_matches_from(["irtt-server"])
+            .unwrap(),
+    )
+    .unwrap();
+    assert_eq!(
+        defaults.resolve_binds(),
+        vec![
+            "[::]:2112".parse().unwrap(),
+            "0.0.0.0:2112".parse().unwrap()
+        ]
+    );
+    assert_eq!(
+        defaults.server_config(),
+        irtt_server::ServerConfig::default()
+    );
+    let args = ServerArgs::try_parse_from([
+        "irtt-server",
+        "--bind",
+        "127.0.0.1:2113",
+        "--bind",
+        "[::1]:2114",
+        "--hmac",
+        "server-cli-test",
+        "--max-sessions",
+        "3",
+        "--max-packet-length",
+        "96",
+        "--min-interval",
+        "25ms",
+        "--burst",
+        "2",
+        "--idle-timeout",
+        "8s",
+        "--max-duration",
+        "1m",
+        "--timestamp-allowance",
+        "single",
+        "--no-dscp",
+    ])
+    .unwrap();
+    assert_eq!(
+        args.resolve_binds(),
+        vec![
+            "127.0.0.1:2113".parse().unwrap(),
+            "[::1]:2114".parse().unwrap()
+        ]
+    );
+    let config = args.server_config();
+    assert_eq!(config.hmac_key(), Some(b"server-cli-test".as_slice()));
+    assert_eq!(config.max_sessions(), 3);
+    assert_eq!(config.max_packet_length(), 96);
+    assert_eq!(config.min_send_interval(), Duration::from_millis(25));
+    assert_eq!(config.burst_allowance(), 2);
+    assert_eq!(config.idle_timeout(), Duration::from_secs(8));
+    assert_eq!(config.max_test_duration(), Some(Duration::from_secs(60)));
+    assert_eq!(config.timestamp_allowance(), TimestampAllowance::Single);
+    assert!(!config.dscp_allowed());
+}
+
+#[cfg(feature = "server")]
+#[test]
+fn server_command_line_binds_replace_the_environment_bind() {
+    use std::net::UdpSocket;
+    // Occupied ports give bounded, observable startup failures, without starting
+    // a daemon or needing a process/signal harness merely to inspect arguments.
+    let environment = UdpSocket::bind("127.0.0.1:0").unwrap();
+    let explicit = UdpSocket::bind("127.0.0.1:0").unwrap();
+    let environment_addr = environment.local_addr().unwrap().to_string();
+    let explicit_addr = explicit.local_addr().unwrap().to_string();
+    for use_explicit in [false, true] {
+        let mut command = Command::new(env!("CARGO_BIN_EXE_irtt-server"));
+        command
+            .env_clear()
+            .env("IRTT_SERVER_BIND", &environment_addr)
+            .env("IRTT_SERVER_MAX_SESSIONS", "invalid")
+            .args(["--max-sessions", "3"]);
+        if use_explicit {
+            command.args(["--bind", "127.0.0.1:0", "--bind", &explicit_addr]);
+        }
+        let output = command.output().unwrap();
+        assert!(!output.status.success());
+        let stderr = String::from_utf8(output.stderr).unwrap();
+        let expected = if use_explicit {
+            &explicit_addr
+        } else {
+            &environment_addr
+        };
+        assert!(
+            stderr.contains(expected),
+            "startup must attempt the selected bind: {stderr}"
+        );
+        assert!(
+            !stderr.contains("listening on"),
+            "partial startup must not announce listeners"
+        );
+    }
+}
+
+// Exercise stdin replacement and EOF through the actual application process.
+#[cfg(feature = "client")]
+#[test]
+fn targets_stdin_supersedes_the_active_set_and_stops_on_eof() {
+    use std::{
+        io::{BufRead, BufReader, Read, Write},
+        process::Stdio,
+        sync::mpsc,
+        thread,
+        time::{Duration, Instant},
+    };
+    let server = in_tree_server::InTreeServer::start(ServerConfig::default());
+    let mut client = ClientProcess(
+        Command::new(env!("CARGO_BIN_EXE_irtt-client"))
+            .env_clear()
+            .args([
+                "--duration",
+                "0",
+                "--targets-stdin",
+                "--interval",
+                "20ms",
+                "--format",
+                "jsonl",
+                "--columns",
+                "target,event",
+            ])
+            .stdin(Stdio::piped())
+            .stdout(Stdio::piped())
+            .stderr(Stdio::piped())
+            .spawn()
+            .unwrap(),
+    );
+    let stdout = client.0.stdout.take().unwrap();
+    let (tx, rx) = mpsc::channel();
+    let reader = thread::spawn(move || {
+        for line in BufReader::new(stdout).lines() {
+            if tx.send(line.unwrap()).is_err() {
+                break;
+            }
+        }
+    });
+    let mut stdin = client.0.stdin.take().unwrap();
+    let mut rows = Vec::new();
+    for target in ["first", "second"] {
+        writeln!(stdin, "{target}={}", server.addr).unwrap();
+        stdin.flush().unwrap();
+        let deadline = Instant::now() + Duration::from_secs(5);
+        loop {
+            let row = rx
+                .recv_timeout(deadline.saturating_duration_since(Instant::now()))
+                .expect("stdin target set did not produce a reply");
+            let replied = row.contains(&format!("\"target\":\"{target}\""))
+                && row.contains("\"event\":\"echo_reply\"");
+            rows.push(row);
+            if replied {
+                break;
+            }
+        }
+    }
+    // Retirement can finish after the newer target's first reply.
+    let deadline = Instant::now() + Duration::from_secs(5);
+    while !rows.iter().any(|row| {
+        row.contains("\"target\":\"first\"") && row.contains("\"event\":\"session_closed\"")
+    }) {
+        rows.push(
+            rx.recv_timeout(deadline.saturating_duration_since(Instant::now()))
+                .expect("superseded stdin target did not retire"),
+        );
+    }
+    drop(stdin);
+    let status = client.wait();
+    reader.join().unwrap();
+    rows.extend(rx.try_iter());
+    let mut stderr = String::new();
+    client
+        .0
+        .stderr
+        .take()
+        .unwrap()
+        .read_to_string(&mut stderr)
+        .unwrap();
+    assert!(status.success(), "{stderr}");
+    assert!(rows
+        .iter()
+        .any(|row| row.contains("\"target\":\"second\"")
+            && row.contains("\"event\":\"session_closed\"")));
+}

crates/irtt-app/tests/support/in_tree_server.rs

@@ -1,11 +1,3 @@
-//! A real `irtt-server` running in-process, for tests that need to prove
-//! `AsyncClient` and the blocking `Client` are equivalent against a real peer.
-//!
-//! This duplicates `crates/irtt-integration-tests/tests/support/in_tree_server.rs`
-//! rather than depending on it: this module backs private (`super::*`) unit
-//! tests here, while the integration crate covers black-box client/server
-//! behavior, and neither can depend on the other's test-only code.
-
 use std::{
     net::{IpAddr, Ipv4Addr, SocketAddr},
     sync::mpsc,

crates/irtt-client/AGENTS.md

@@ -26,30 +26,30 @@ configuration (`try_enable_tx_timestamping` restores it explicitly) and
 timing falls back to userspace `sent_at` as it always has. TX capability
 failure is never a public error and is never logged from the library.
 
-### Correlation invariant: kernel ID == wire sequence
+### Best-effort kernel-ID correlation
 
-The client uses the kernel's automatic `OPT_ID` directly as the probe's wire
-sequence number — no separate correlation map. This is safe because:
+The client uses the kernel's automatic `OPT_ID` as the probe's wire-sequence
+correlation ID — no separate correlation map. On the normal successful-send
+path, both counters start at zero after Open and advance together. This is
+not a permanent identity: a kernel ID can theoretically be consumed while a
+send is being prepared and then survive a subsequent send failure, leaving
+kernel IDs one or more steps ahead of `next_wire_seq`. Do not restore an
+assumption that failed or nonblocking sends cannot cause that desynchrony.
 
-- **A failed/nonblocking send never consumes an ID.** Linux increments the
-  per-socket ID counter (`sk->sk_tskey`) speculatively while building a
-  datagram and rolls the increment back (`atomic_dec`) on every error path
-  out of `__ip_append_data`/`__ip6_append_data`
-  (`net/ipv4/ip_output.c`, `net/ipv6/ip6_output.c`), guarded by a local
-  `hold_tskey` flag. A `WouldBlock` `try_send` therefore can never leave a
-  gap in, or otherwise advance, the ID the kernel will assign to the next
-  *successful* submission. (`include/net/sock.h`'s `_sock_tx_timestamp`
-  performs the same increment for the non-corked path.) Client-side, the
-  existing send transaction only calls `commit_probe_sent` — which is the
-  only thing that advances `next_wire_seq` — after a successful socket send;
-  a `WouldBlock` result never reaches it.
-- **The two counters start together and advance together.** `wire_seq`
-  starts at 0 on every successful Open (`SessionMachine::commit_open` builds
-  a fresh `ActiveSession` with `next_wire_seq: 0`) and advances by exactly 1
-  only via `commit_probe_sent`, which only runs after a confirmed successful
-  send — the same condition under which the kernel's counter advances by 1.
-  TX timestamping is enabled only after that same successful Open and before
-  any probe is sent, so both counters' zero points line up exactly.
+The effect is confined to the optional timing enhancement. A kernel timestamp
+whose ID cannot be matched to a pending or retained timed-out probe is
+discarded, as is any implausible timestamp; `sent_at` remains the ordinary
+userspace fallback. **After every failed probe submission, disable kernel-ID
+correlation for the rest of that session.** A gap means an otherwise plausible
+later ID can name the wrong probe, so subsequent error-queue timestamps must
+be discarded rather than attached by ID. This is safe because:
+
+- **Normal successful sends track together.** `wire_seq` starts at 0 on every
+  successful Open (`SessionMachine::commit_open` builds a fresh
+  `ActiveSession` with `next_wire_seq: 0`) and advances by exactly 1 only via
+  `commit_probe_sent`, after a confirmed successful socket send. TX
+  timestamping is enabled after that same successful Open and before any probe
+  is sent, so the normal zero points line up.
 - **One socket, one session, no reopen.** `SessionMachine`'s state machine
   only reaches `Open` from `Connected`, and `commit_open`/`commit_local_close`
   never route back to `Connected`. A `Client`/`AsyncClient` cannot reopen a
@@ -93,6 +93,29 @@ risks clearing readiness state that the normal Echo receive path depends on.
 There is no background task or second `AsyncFd` around the Tokio-owned
 socket.
 
+### Testing kernel timestamp behavior
+
+The requirements above describe production behavior, not a required unit-test
+architecture.
+
+Prefer Linux tests that exercise the real socket and kernel timestamp path
+through production APIs. A test intended to prove TX timestamp support must
+actually require and observe a kernel TX timestamp when running on a supported
+Linux environment; accepting the userspace fallback does not prove that path.
+
+Likewise, prefer observable socket/client behavior for genuine error-queue
+errors and bounded draining where it can reasonably be induced.
+
+Do not restore synthetic `ControlMessageOwned` permutations, classifier-unit
+suites, raw ancillary fixtures, test-only socket hooks, or other internal seams
+solely to cover every `MSG_ERRQUEUE` branch. `nix` owns ancillary-message
+decoding and ABI safety; `irtt-client` tests should primarily prove its own
+observable interpretation and behavior through the real path.
+
+If some invariant cannot reasonably be induced through a production interface,
+a small focused internal test may be retained, but the burden is on that test to
+justify why integration coverage is insufficient.
+
 ## Retained state
 
 `PendingProbe` carries an optional `kernel_tx_timestamp: Option<SystemTime>`
@@ -127,7 +150,8 @@ remains anchored to before the send, on purpose, so the existing pre-send
 timeout/overflow/no-send contract is unchanged. Only the *measurement*
 `sent_at` moved to after the send. A `WouldBlock` `try_send` (Tokio) never
 samples a `sent_at`, never calls `finalize_probe_commit`'s matching
-`commit_probe_sent`, and never advances the machine or schedule; each retry
+`commit_probe_sent`, and never advances the machine; the managed runner advances cadence only
+  after an accepted send; each retry
 gets its own fresh pre-send anchor, and only a successful attempt's anchor
 and `sent_at` are ever retained.
 

crates/irtt-client/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "irtt-client"
-version = "0.5.0"
+version = "0.5.3"
 description = "IRTT-compatible Rust client library"
 edition.workspace = true
 license.workspace = true
@@ -14,7 +14,7 @@ categories = ["network-programming"]
 [dependencies]
 irtt-proto.workspace = true
 socket2 = { version = "0.6.5", features = ["all"] }
-thiserror = "2.0.20"
+thiserror = "2.0.21"
 tokio = { version = "1.53.1", default-features = false, features = ["rt", "net", "time", "sync"], optional = true}
 
 [target.'cfg(target_os = "linux")'.dependencies]
@@ -25,6 +25,9 @@ default = []
 ancillary = ["dep:nix"]
 tokio = ["dep:tokio"]
 
+[dev-dependencies]
+irtt-server.workspace = true
+
 [package.metadata.docs.rs]
 all-features = true
 cargo-args = ["-Zunstable-options", "-Zrustdoc-scrape-examples"]
@@ -42,8 +45,3 @@ doc-scrape-examples = true
 name = "managed_client"
 required-features = ["tokio"]
 doc-scrape-examples = true
-
-[dev-dependencies]
-irtt-server.workspace = true
-proptest = "1.11.0"
-tokio = { version = "1.53.1", default-features = false, features = ["rt", "sync"] }

crates/irtt-client/README.md

@@ -22,6 +22,13 @@ binaries are built on.
   runtime, and `BlockingManagedClient` for synchronous callers, which owns its
   own dedicated current-thread runtime.
 
+`Client` and `AsyncClient` send one probe whenever called. They expose the
+negotiated parameters, pending-probe status, and timeout deadlines; callers
+own cadence and run duration. The managed driver provides fixed cadence,
+missed-slot handling, finite runs, and staggered or burst pacing. Low-level
+`EchoSent` events leave `scheduled_at` and `timer_error` absent; the managed
+driver supplies those schedule measurements.
+
 Tokio stays optional: the default build has no runtime and no Tokio
 dependency at all.
 

crates/irtt-client/examples/blocking_client.rs

@@ -18,7 +18,7 @@
 
 use std::time::{Duration, Instant};
 
-use irtt_client::{Client, ClientConfig, ClientEvent};
+use irtt_client::{Client, ClientConfig, ClientEvent, OpenOutcome};
 
 const RUN_DURATION: Duration = Duration::from_secs(2);
 
@@ -45,32 +45,42 @@ fn main() {
         }
     };
 
-    match client.open() {
-        Ok(outcome) => println!("session opened: {outcome:?}"),
+    let negotiated = match client.open() {
+        Ok(OpenOutcome::Started {
+            event, negotiated, ..
+        }) => {
+            println!("session opened: {event:?}");
+            negotiated
+        }
+        Ok(OpenOutcome::NoTestCompleted { event, .. }) => {
+            println!("{event:?}");
+            return;
+        }
         Err(err) => {
             eprintln!("open failed (is a server running at 127.0.0.1:2112?): {err}");
             return;
         }
-    }
+    };
 
-    // The run itself lasts `duration`, but a lost probe isn't classified as
-    // `EchoLoss` until `probe_timeout()` after it was sent; wait at least
-    // that much past the run's own end so a loss near the end can still be
-    // observed and printed before this example gives up and closes.
-    let deadline = Instant::now() + RUN_DURATION + client.probe_timeout();
-    while Instant::now() < deadline && !client.is_run_complete() {
-        // send_probe is caller-paced: only call it once its own schedule
-        // says a probe is due, rather than as fast as the loop spins.
-        if client
-            .next_send_deadline()
-            .is_some_and(|send_at| Instant::now() >= send_at)
-        {
-            // A failed send retains its prepared probe without advancing the
-            // schedule, so a persistent error (e.g. the interface going
-            // down) would otherwise make this loop retry silently until the
-            // safety deadline instead of reporting it.
+    // This loop owns cadence and duration. The transport sends whenever called.
+    let interval = Duration::from_nanos(negotiated.params.interval_ns as u64);
+    let start = Instant::now();
+    let end = start + Duration::from_nanos(negotiated.params.duration_ns as u64);
+    let deadline = end + client.probe_timeout();
+    let mut next_send = start;
+    while Instant::now() < deadline && !client.is_peer_closed() {
+        let now = Instant::now();
+        if now >= end && !client.has_pending_probes() {
+            break;
+        }
+        if now < end && now >= next_send {
             match client.send_probe() {
-                Ok(events) => events.iter().for_each(print_event),
+                Ok(events) => {
+                    events.iter().for_each(print_event);
+                    while next_send <= Instant::now() {
+                        next_send += interval;
+                    }
+                }
                 Err(err) => {
                     eprintln!("send failed: {err}");
                     break;
@@ -93,6 +103,9 @@ fn main() {
         }
     }
 
+    if client.is_peer_closed() {
+        return;
+    }
     match client.close() {
         Ok(events) => events.iter().for_each(print_event),
         Err(err) => eprintln!("close failed: {err}"),

crates/irtt-client/examples/tokio_client.rs

@@ -18,7 +18,7 @@
 
 use std::time::{Duration, Instant};
 
-use irtt_client::{AsyncClient, ClientConfig, ClientEvent};
+use irtt_client::{AsyncClient, ClientConfig, ClientEvent, OpenOutcome};
 
 /// Upper bound on how long the receive wait can go without also calling
 /// `poll_timeouts()`. `AsyncClient` does not expose the earliest pending
@@ -58,24 +58,43 @@ async fn run() {
         }
     };
 
-    match client.open().await {
-        Ok(outcome) => println!("session opened: {outcome:?}"),
+    let negotiated = match client.open().await {
+        Ok(OpenOutcome::Started {
+            event, negotiated, ..
+        }) => {
+            println!("session opened: {event:?}");
+            negotiated
+        }
+        Ok(OpenOutcome::NoTestCompleted { event, .. }) => {
+            println!("{event:?}");
+            return;
+        }
         Err(err) => {
             eprintln!("open failed (is a server running at 127.0.0.1:2112?): {err}");
             return;
         }
-    }
+    };
 
-    while !client.is_run_complete() {
+    // This loop owns cadence and duration. The transport sends whenever called.
+    let interval = Duration::from_nanos(negotiated.params.interval_ns as u64);
+    let start = Instant::now();
+    let end = start + Duration::from_nanos(negotiated.params.duration_ns as u64);
+    let deadline = end + client.probe_timeout();
+    let mut next_send = start;
+    while Instant::now() < deadline && !client.is_peer_closed() {
+        if Instant::now() >= end && !client.has_pending_probes() {
+            break;
+        }
         // Bound the receive wait by the next send/timeout deadline, rather
         // than awaiting recv() unconditionally: a lost or rate-limited reply
         // must not stall pacing or timeout classification indefinitely.
-        let wake_at = client
-            .next_send_deadline()
+        let wake_at = (next_send < end)
+            .then_some(next_send)
             .into_iter()
+            .chain(client.next_probe_timeout_deadline())
             .chain(std::iter::once(Instant::now() + TIMEOUT_POLL_INTERVAL))
             .min()
-            .expect("the fixed poll-interval deadline is always present");
+            .unwrap();
 
         let recv_result = tokio::select! {
             events = client.recv() => Some(events),
@@ -91,16 +110,14 @@ async fn run() {
             }
         }
 
-        if client
-            .next_send_deadline()
-            .is_some_and(|send_at| Instant::now() >= send_at)
-        {
-            // A failed send retains its prepared probe without advancing the
-            // schedule, so a persistent error (e.g. the interface going
-            // down) would otherwise make this loop retry forever instead of
-            // reporting it.
+        if Instant::now() < end && Instant::now() >= next_send {
             match client.send_probe().await {
-                Ok(events) => events.iter().for_each(print_event),
+                Ok(events) => {
+                    events.iter().for_each(print_event);
+                    while next_send <= Instant::now() {
+                        next_send += interval;
+                    }
+                }
                 Err(err) => {
                     eprintln!("send failed: {err}");
                     break;
@@ -116,6 +133,9 @@ async fn run() {
         }
     }
 
+    if client.is_peer_closed() {
+        return;
+    }
     match client.close().await {
         Ok(events) => events.iter().for_each(print_event),
         Err(err) => eprintln!("close failed: {err}"),

crates/irtt-client/src/async_client.rs

@@ -7,20 +7,10 @@ use std::{
     time::{Duration, Instant},
 };
 
-#[cfg(test)]
-use std::{
-    cell::{Cell, RefCell},
-    collections::VecDeque,
-};
-
 use tokio::time;
 
 use crate::{
-    client::{
-        echo_sent_event,
-        schedule::{instant_abs_diff, ProbeSchedule},
-        validate_datagram_length,
-    },
+    client::{echo_sent_event, validate_datagram_length},
     config::ClientConfig,
     error::ClientError,
     event::{ClientEvent, OpenOutcome},
@@ -54,13 +44,9 @@ const OPEN_POLL_WORK_BUDGET: usize = 64;
 /// this crate already bounds open-attempt work keeps that impossible.
 const RECV_POLL_WORK_BUDGET: usize = 64;
 
-#[cfg(test)]
-use crate::client::ProbeSendTimestamps;
-
 #[derive(Debug)]
 struct PreparedAsyncOpen {
     machine: PreparedOpenAcceptance,
-    schedule: Option<ProbeSchedule>,
     recv_buffer_len: Option<usize>,
     negotiated_traffic_class: Option<u8>,
 }
@@ -99,7 +85,7 @@ impl AsyncOpenCleanup {
 /// Owned state for one asynchronous open transaction.
 ///
 /// This state deliberately contains no reference to [`AsyncClient`], allowing
-/// a future managed target to store the client and opening state side by side.
+/// a managed target to store the client and opening state side by side.
 #[derive(Debug)]
 pub(crate) struct AsyncOpenState {
     attempt: usize,
@@ -156,11 +142,6 @@ impl AsyncOpenState {
         self.stopped_after_current_attempt
     }
 
-    #[cfg(test)]
-    pub(crate) fn has_retained_cleanup(&self) -> bool {
-        self.cleanup.is_some()
-    }
-
     fn deadline(&self) -> Instant {
         self.deadline
             .expect("an open attempt has an active deadline")
@@ -173,80 +154,40 @@ impl AsyncOpenState {
     }
 }
 
-#[cfg(test)]
-#[derive(Debug)]
-enum InjectedSend {
-    WouldBlock,
-    Error,
-    ReportedLength(usize),
-}
-
-#[cfg(test)]
-#[derive(Debug, Default)]
-struct AsyncClientTestHooks {
-    sends: RefCell<VecDeque<InjectedSend>>,
-    send_attempts: Cell<usize>,
-    receive_would_block: Cell<usize>,
-    /// Number of subsequent receive attempts (`poll_open` or `poll_recv`)
-    /// that should report `io::ErrorKind::Interrupted` instead of performing
-    /// a real nonblocking receive, deterministically exercising interrupted-
-    /// syscall retry behavior.
-    inject_recv_interrupted: Cell<usize>,
-    fail_open_dscp: Cell<bool>,
-    fail_cleanup_send: Cell<bool>,
-    fail_peer_close_dscp: Cell<bool>,
-    fail_dscp_restore: Cell<bool>,
-    pause_open_cleanup_before_send: Cell<bool>,
-    pause_open_before_writable: Cell<bool>,
-    pause_open_before_readable: Cell<bool>,
-    pause_probe_before_writable: Cell<bool>,
-    pause_close_before_writable: Cell<bool>,
-    pause_close_after_would_block: Cell<bool>,
-    probe_timestamps: RefCell<VecDeque<ProbeSendTimestamps>>,
-    close_sent_at: Cell<Option<ClientTimestamp>>,
-}
-
-#[cfg(test)]
-impl AsyncClientTestHooks {
-    fn try_send(&self, socket: &tokio::net::UdpSocket, packet: &[u8]) -> io::Result<usize> {
-        self.send_attempts.set(self.send_attempts.get() + 1);
-        if let Some(injected) = self.sends.borrow_mut().pop_front() {
-            return match injected {
-                InjectedSend::WouldBlock => Err(io::Error::from(io::ErrorKind::WouldBlock)),
-                InjectedSend::Error => Err(io::Error::other("injected send failure")),
-                InjectedSend::ReportedLength(bytes) => Ok(bytes),
-            };
-        }
-        socket.try_send(packet)
-    }
-
-    fn take_probe_timestamps(&self) -> Option<ProbeSendTimestamps> {
-        self.probe_timestamps.borrow_mut().pop_front()
-    }
-
-    /// Consumes one pending injected interruption, if any, reporting whether
-    /// the caller should report `io::ErrorKind::Interrupted` instead of
-    /// attempting a real receive.
-    fn take_injected_interrupted(&self) -> bool {
-        let remaining = self.inject_recv_interrupted.get();
-        if remaining == 0 {
-            return false;
-        }
-        self.inject_recv_interrupted.set(remaining - 1);
-        true
-    }
-}
-
 /// Low-level Tokio IRTT client for one connected UDP target.
 ///
 /// `AsyncClient` does not construct, own, or store a Tokio runtime. Its async
 /// methods are polled by the caller and require a current Tokio runtime with I/O
 /// and time enabled.
+///
+/// # Example
+///
+/// Use this low-level adapter when the application already owns Tokio and wants
+/// to drive the session lifecycle itself. This example type-checks without
+/// contacting a server.
+///
+/// ```no_run
+/// use irtt_client::{AsyncClient, ClientConfig};
+///
+/// # async fn run() -> Result<(), Box<dyn std::error::Error>> {
+/// let mut client = AsyncClient::connect(ClientConfig::default()).await?;
+/// let outcome = client.open().await?;
+/// println!("opened: {outcome:?}");
+/// let sent = client.send_probe().await?;
+/// println!("sent: {sent:?}");
+/// let received = client.recv().await?;
+/// println!("received: {received:?}");
+/// let timed_out = client.poll_timeouts()?;
+/// println!("timeouts: {timed_out:?}");
+/// let closed = client.close().await?;
+/// println!("closed: {closed:?}");
+/// # Ok(())
+/// # }
+/// ```
 #[derive(Debug)]
 pub struct AsyncClient {
     socket: tokio::net::UdpSocket,
     machine: SessionMachine,
-    schedule: Option<ProbeSchedule>,
     remote: SocketAddr,
     recv_buffer: Vec<u8>,
     applied_traffic_class: Option<u8>,
@@ -255,8 +196,6 @@ pub struct AsyncClient {
     /// See `Client::tx_timestamping_enabled` in `client.rs` for the
     /// invariant this tracks; it is the same adapter-owned capability flag.
     tx_timestamping_enabled: bool,
-    #[cfg(test)]
-    test_hooks: AsyncClientTestHooks,
 }
 
 impl AsyncClient {
@@ -277,15 +216,12 @@ impl AsyncClient {
         Ok(Self {
             socket,
             machine,
-            schedule: None,
             remote,
             recv_buffer: vec![0_u8; recv_buffer_size(false, None)?],
             applied_traffic_class: None,
             prepared_open: Some(prepared_open),
             prepared_probe: None,
             tx_timestamping_enabled: false,
-            #[cfg(test)]
-            test_hooks: AsyncClientTestHooks::default(),
         })
     }
 
@@ -297,16 +233,16 @@ impl AsyncClient {
     /// ignored without resending the request.
     ///
     /// Dropping this future before trusted acceptance leaves the local machine
-    /// connected with no committed schedule or negotiated adapter state. If it
-    /// is dropped during best-effort post-token cleanup, cleanup may remain
-    /// incomplete because this low-level client never detaches cleanup work.
+    /// connected with no negotiated adapter state. If it is dropped during
+    /// best-effort post-token cleanup, cleanup may remain incomplete because
+    /// this low-level client never detaches cleanup work.
     pub async fn open(&mut self) -> Result<OpenOutcome, ClientError> {
         let mut state = AsyncOpenState::new();
         poll_fn(|cx| self.poll_open(&mut state, cx)).await
     }
 
-    /// Send one caller-paced probe with transactional protocol and schedule
-    /// commits.
+    /// Send one echo probe now, committing protocol state only after acceptance.
+    /// The caller owns pacing and run duration.
     ///
     /// A prepared packet is retained across readiness false positives,
     /// cancellation, and socket errors so a later call retries the same logical
@@ -387,10 +323,6 @@ impl AsyncClient {
             }
 
             if !state.request_submitted {
-                #[cfg(test)]
-                if self.test_hooks.pause_open_before_writable.replace(false) {
-                    return Poll::Pending;
-                }
                 match poll_writable_until(&self.socket, state.deadline_timer(), cx) {
                     Poll::Pending => return Poll::Pending,
                     Poll::Ready(Err(error)) => return Poll::Ready(Err(error)),
@@ -405,9 +337,6 @@ impl AsyncClient {
                     .prepared_open
                     .as_ref()
                     .expect("connected clients retain their prepared open request");
-                #[cfg(test)]
-                let send_result = self.test_hooks.try_send(&self.socket, &request.bytes);
-                #[cfg(not(test))]
                 let send_result = self.socket.try_send(&request.bytes);
                 match send_result {
                     Ok(bytes) => {
@@ -421,10 +350,6 @@ impl AsyncClient {
                 }
             }
 
-            #[cfg(test)]
-            if self.test_hooks.pause_open_before_readable.replace(false) {
-                return Poll::Pending;
-            }
             match poll_readable_until(&self.socket, state.deadline_timer(), cx) {
                 Poll::Pending => return Poll::Pending,
                 Poll::Ready(Err(error)) => return Poll::Ready(Err(error)),
@@ -438,10 +363,6 @@ impl AsyncClient {
                 Poll::Ready(Ok(true)) => {}
             }
 
-            #[cfg(test)]
-            if self.test_hooks.take_injected_interrupted() {
-                continue;
-            }
             let datagram = match try_recv_tokio_datagram(&self.socket, &mut state.buffer) {
                 Ok(datagram) => datagram,
                 // WouldBlock is a readiness false positive; Interrupted
@@ -489,7 +410,7 @@ impl AsyncClient {
                     continue;
                 }
             };
-            let prepared = match self.prepare_async_open(machine, datagram.received_at) {
+            let prepared = match self.prepare_async_open(machine) {
                 Ok(prepared) => prepared,
                 Err(failure) => {
                     state.cleanup = Some(AsyncOpenCleanup::Adapter(failure));
@@ -514,19 +435,11 @@ impl AsyncClient {
         }
         if self.prepared_probe.is_none() {
             match self.machine.prepare_probe() {
-                Ok(prepared) => self.prepared_probe = prepared,
+                Ok(prepared) => self.prepared_probe = Some(prepared),
                 Err(error) => return Poll::Ready(Err(error)),
             }
         }
-        if self.prepared_probe.is_none() {
-            return Poll::Ready(Ok(Vec::new()));
-        }
-
         loop {
-            #[cfg(test)]
-            if self.test_hooks.pause_probe_before_writable.replace(false) {
-                return Poll::Pending;
-            }
             match self.socket.poll_send_ready(cx) {
                 Poll::Pending => return Poll::Pending,
                 Poll::Ready(Ok(())) => {}
@@ -535,23 +448,6 @@ impl AsyncClient {
                 }
             }
 
-            #[cfg(test)]
-            let test_timestamps = self.test_hooks.take_probe_timestamps();
-            #[cfg(not(test))]
-            let permission_at = Instant::now();
-            #[cfg(test)]
-            let permission_at = test_timestamps
-                .map(|timestamps| timestamps.permission_at)
-                .unwrap_or_else(Instant::now);
-
-            let schedule = self
-                .schedule
-                .as_mut()
-                .expect("open sessions always have a probe schedule");
-            if !schedule.permit_probe_at(permission_at) {
-                self.prepared_probe = None;
-                return Poll::Ready(Ok(Vec::new()));
-            }
             let prepared = self
                 .prepared_probe
                 .as_ref()
@@ -560,11 +456,6 @@ impl AsyncClient {
                 Ok(preflight) => preflight,
                 Err(error) => return Poll::Ready(Err(error)),
             };
-            let schedule_commit =
-                match schedule.preflight_caller_commit(machine_preflight.next_packets_sent) {
-                    Ok(commit) => commit,
-                    Err(error) => return Poll::Ready(Err(error)),
-                };
             let mut events = Vec::new();
             if let Err(source) = events.try_reserve(1) {
                 return Poll::Ready(Err(ClientError::AllocationFailed {
@@ -572,20 +463,14 @@ impl AsyncClient {
                     source,
                 }));
             }
-
             let expected_bytes = prepared.bytes.len();
-            let scheduled_at = schedule_commit.scheduled_at;
+
             // Private pre-send anchor: finalizes all fallible commit work
             // (timeout deadline arithmetic, kernel TX lower bound) before
             // the send attempt. A WouldBlock retry samples a fresh one on
             // the next loop iteration; only the successful attempt's anchor
             // is retained (via `machine_commit`/`commit_probe_sent` below).
-            #[cfg(not(test))]
             let send_anchor = ClientTimestamp::now();
-            #[cfg(test)]
-            let send_anchor = test_timestamps
-                .map(|timestamps| timestamps.send_anchor)
-                .unwrap_or_else(ClientTimestamp::now);
             let machine_commit = match self
                 .machine
                 .finalize_probe_commit(machine_preflight, send_anchor)
@@ -593,61 +478,40 @@ impl AsyncClient {
                 Ok(commit) => commit,
                 Err(error) => return Poll::Ready(Err(error)),
             };
-            #[cfg(not(test))]
             let send_call_start = Instant::now();
-            #[cfg(test)]
-            let send_call_start = test_timestamps
-                .map(|timestamps| timestamps.send_call_start)
-                .unwrap_or_else(Instant::now);
-            #[cfg(test)]
-            let send_result = self.test_hooks.try_send(&self.socket, &prepared.bytes);
-            #[cfg(not(test))]
             let send_result = self.socket.try_send(&prepared.bytes);
             let bytes = match send_result {
                 Ok(bytes) => bytes,
-                // No sent_at measurement, no machine commit, no schedule
-                // commit: the transaction is fully discarded and retried
+                // No measurement or machine commit: retry the transaction
                 // with a fresh send_anchor on the next loop iteration.
-                Err(error) if error.kind() == io::ErrorKind::WouldBlock => continue,
-                Err(error) => return Poll::Ready(Err(ClientError::Socket(error))),
+                Err(error) if error.kind() == io::ErrorKind::WouldBlock => {
+                    self.machine.invalidate_kernel_tx_correlation();
+                    continue;
+                }
+                Err(error) => {
+                    self.machine.invalidate_kernel_tx_correlation();
+                    return Poll::Ready(Err(ClientError::Socket(error)));
+                }
             };
-
-            #[cfg(not(test))]
             let send_finished_at = Instant::now();
-            #[cfg(test)]
-            let send_finished_at = test_timestamps
-                .map(|timestamps| timestamps.send_finished_at)
-                .unwrap_or_else(Instant::now);
+
             // Public post-send measurement, captured only after the
-            // successful send above. The subsequent machine/schedule commit
+            // successful send above. The subsequent machine commit
             // is infallible.
-            #[cfg(not(test))]
             let sent_at = ClientTimestamp::now();
-            #[cfg(test)]
-            let sent_at = test_timestamps
-                .map(|timestamps| timestamps.sent_at)
-                .unwrap_or_else(ClientTimestamp::now);
             let sent = self
                 .machine
                 .commit_probe_sent(machine_commit, sent_at, bytes);
-            schedule.commit(schedule_commit);
             self.prepared_probe = None;
-
             let send_call = send_finished_at.saturating_duration_since(send_call_start);
-            let timer_error = instant_abs_diff(sent_at.mono, scheduled_at);
+
             if let Err(error) = validate_datagram_length(expected_bytes, bytes) {
                 return Poll::Ready(Err(error));
             }
             if let Err(error) = self.drain_tx_timestamps() {
                 return Poll::Ready(Err(error));
             }
-            events.push(echo_sent_event(
-                self.remote,
-                sent,
-                send_call,
-                scheduled_at,
-                timer_error,
-            ));
+            events.push(echo_sent_event(self.remote, sent, send_call));
             return Poll::Ready(Ok(events));
         }
     }
@@ -668,17 +532,7 @@ impl AsyncClient {
                     return Poll::Ready(Err(ClientError::Socket(error)));
                 }
             }
-            #[cfg(test)]
-            if self.test_hooks.receive_would_block.get() > 0 {
-                self.test_hooks
-                    .receive_would_block
-                    .set(self.test_hooks.receive_would_block.get() - 1);
-                continue;
-            }
-            #[cfg(test)]
-            if self.test_hooks.take_injected_interrupted() {
-                continue;
-            }
+
             let datagram = match try_recv_tokio_datagram(&self.socket, &mut self.recv_buffer) {
                 Ok(datagram) => datagram,
                 // See `RECV_POLL_WORK_BUDGET`: both a readiness false
@@ -712,9 +566,8 @@ impl AsyncClient {
                 Err(error) => return Poll::Ready(Err(error)),
             };
             if self.machine.is_peer_closed() {
-                self.schedule = None;
                 self.prepared_probe = None;
-                if self.clear_peer_close_dscp().is_ok() {
+                if clear_dscp_on_tokio_socket(&self.socket, self.remote).is_ok() {
                     self.applied_traffic_class = None;
                 }
             }
@@ -747,10 +600,6 @@ impl AsyncClient {
             let previous_traffic_class = self.applied_traffic_class;
             let expected_bytes = prepared.bytes.len();
 
-            #[cfg(test)]
-            if self.test_hooks.pause_close_before_writable.replace(false) {
-                return Poll::Pending;
-            }
             match self.socket.poll_send_ready(cx) {
                 Poll::Pending => return Poll::Pending,
                 Poll::Ready(Ok(())) => {}
@@ -758,19 +607,11 @@ impl AsyncClient {
                     return Poll::Ready(Err(ClientError::Socket(error)));
                 }
             }
-            if let Err(error) = self.clear_close_dscp() {
+            if let Err(error) = clear_dscp_on_tokio_socket(&self.socket, self.remote) {
                 return Poll::Ready(Err(error));
             }
-            let mut rollback = DscpRollback::armed(
-                &self.socket,
-                self.remote,
-                previous_traffic_class,
-                #[cfg(test)]
-                &self.test_hooks.fail_dscp_restore,
-            );
-            #[cfg(test)]
-            let send_result = self.test_hooks.try_send(&self.socket, prepared.bytes);
-            #[cfg(not(test))]
+            let mut rollback =
+                DscpRollback::armed(&self.socket, self.remote, previous_traffic_class);
             let send_result = self.socket.try_send(prepared.bytes);
             let bytes = match send_result {
                 Ok(bytes) => bytes,
@@ -778,28 +619,18 @@ impl AsyncClient {
                     if let Err(error) = rollback.restore() {
                         return Poll::Ready(Err(error));
                     }
-                    #[cfg(test)]
-                    if self.test_hooks.pause_close_after_would_block.replace(false) {
-                        return Poll::Pending;
-                    }
+
                     continue;
                 }
                 Err(error) => return Poll::Ready(Err(ClientError::Socket(error))),
             };
 
-            #[cfg(not(test))]
             let close_sent_at = ClientTimestamp::now();
-            #[cfg(test)]
-            let close_sent_at = self
-                .test_hooks
-                .close_sent_at
-                .take()
-                .unwrap_or_else(ClientTimestamp::now);
+
             let event = self
                 .machine
                 .commit_local_close(prepared.commit, close_sent_at);
             rollback.disarm();
-            self.schedule = None;
             self.prepared_probe = None;
             self.applied_traffic_class = None;
 
@@ -811,33 +642,19 @@ impl AsyncClient {
         }
     }
 
-    /// Return the next scheduled probe deadline.
-    pub fn next_send_deadline(&self) -> Option<Instant> {
-        if !self.machine.is_open() {
-            return None;
-        }
-        self.schedule.as_ref()?.next_send_deadline()
-    }
-
-    pub(crate) fn probe_interval(&self) -> Option<Duration> {
-        if !self.machine.is_open() {
-            return None;
-        }
-        self.schedule.as_ref().map(ProbeSchedule::interval)
-    }
-
     /// Return the configured local probe timeout.
     pub fn probe_timeout(&self) -> Duration {
         self.machine.probe_timeout()
     }
 
-    /// Return whether the current run has completed.
-    pub fn is_run_complete(&self) -> bool {
-        self.machine.is_terminal()
-            || self
-                .schedule
-                .as_ref()
-                .is_some_and(|schedule| schedule.is_finished() && self.machine.pending_is_empty())
+    /// Negotiated parameters of the currently open session.
+    pub fn negotiated_params(&self) -> Option<&crate::NegotiatedParams> {
+        self.machine.negotiated_params()
+    }
+
+    /// Whether any sent probes still await a reply or timeout.
+    pub fn has_pending_probes(&self) -> bool {
+        !self.machine.pending_is_empty()
     }
 
     /// Return whether an authenticated peer close ended the session.
@@ -853,7 +670,8 @@ impl AsyncClient {
         self.machine.packets_sent()
     }
 
-    pub(crate) fn next_probe_timeout_deadline(&self) -> Option<Instant> {
+    /// Earliest timeout deadline among probes still awaiting a reply.
+    pub fn next_probe_timeout_deadline(&self) -> Option<Instant> {
         self.machine.next_probe_timeout_deadline()
     }
 
@@ -865,64 +683,17 @@ impl AsyncClient {
         self.prepared_probe = None;
     }
 
-    #[cfg(test)]
-    pub(crate) fn retain_open_cleanup_once(&self) {
-        self.test_hooks.fail_open_dscp.set(true);
-        self.test_hooks.pause_open_cleanup_before_send.set(true);
-    }
-
-    #[cfg(test)]
-    pub(crate) fn poll_recv_ready_for_test(&self, cx: &mut Context<'_>) -> Poll<io::Result<()>> {
-        self.socket.poll_recv_ready(cx)
-    }
-
-    #[cfg(test)]
-    pub(crate) fn remove_pending_for_test(
-        &mut self,
-        wire_seq: u32,
-    ) -> Option<crate::probe::PendingProbe> {
-        self.machine.remove_pending_for_test(wire_seq)
-    }
-
-    #[cfg(test)]
-    pub(crate) fn replace_pending_for_test(&mut self, probe: crate::probe::PendingProbe) {
-        self.machine.replace_pending_for_test(probe);
-    }
-
-    pub(crate) fn skip_missed_probe_slots_at(&mut self, now: Instant) -> Result<(), ClientError> {
-        let Some(schedule) = self.schedule.as_mut() else {
-            return Ok(());
-        };
-        let Some(deadline) = schedule.next_send_deadline() else {
-            return Ok(());
-        };
-        if deadline > now {
-            return Ok(());
-        }
-        let commit = schedule.preflight_managed_commit(deadline, now)?;
-        schedule.commit(commit);
-        Ok(())
-    }
-
     fn prepare_async_open(
         &mut self,
         machine: PreparedOpenAcceptance,
-        opened_at: ClientTimestamp,
     ) -> Result<PreparedAsyncOpen, Box<PreparedAsyncOpenFailure>> {
         let Some(negotiated) = machine.normal_negotiated() else {
             return Ok(PreparedAsyncOpen {
                 machine,
-                schedule: None,
                 recv_buffer_len: None,
                 negotiated_traffic_class: None,
             });
         };
-        let schedule = match ProbeSchedule::new(opened_at.mono, negotiated) {
-            Ok(schedule) => schedule,
-            Err(primary) => {
-                return Err(Box::new(PreparedAsyncOpenFailure { primary, machine }));
-            }
-        };
         let recv_buffer_len = match recv_buffer_size(self.machine.has_hmac(), Some(negotiated)) {
             Ok(size) => size,
             Err(primary) => {
@@ -950,17 +721,7 @@ impl AsyncClient {
                 machine,
             }));
         }
-        #[cfg(test)]
-        let dscp_result = if self.test_hooks.fail_open_dscp.replace(false) {
-            Err(ClientError::SocketOption {
-                operation: "set negotiated DSCP",
-                remote: self.remote,
-                source: io::Error::other("injected negotiated DSCP failure"),
-            })
-        } else {
-            apply_traffic_class_to_tokio_socket(&self.socket, self.remote, negotiated_traffic_class)
-        };
-        #[cfg(not(test))]
+
         let dscp_result = apply_traffic_class_to_tokio_socket(
             &self.socket,
             self.remote,
@@ -973,7 +734,6 @@ impl AsyncClient {
 
         Ok(PreparedAsyncOpen {
             machine,
-            schedule: Some(schedule),
             recv_buffer_len: Some(recv_buffer_len),
             negotiated_traffic_class: Some(negotiated_traffic_class),
         })
@@ -984,7 +744,7 @@ impl AsyncClient {
             self.recv_buffer.resize(recv_buffer_len, 0);
         }
         let outcome = self.machine.commit_open(prepared.machine);
-        self.schedule = prepared.schedule;
+
         self.applied_traffic_class = prepared.negotiated_traffic_class;
         self.prepared_open = None;
         self.tx_timestamping_enabled = try_enable_tx_timestamping(&self.socket);
@@ -1017,23 +777,6 @@ impl AsyncClient {
         else {
             return Poll::Ready(Err(state.cleanup.take().unwrap().into_primary()));
         };
-
-        #[cfg(test)]
-        if self
-            .test_hooks
-            .pause_open_cleanup_before_send
-            .replace(false)
-        {
-            return Poll::Pending;
-        }
-
-        #[cfg(test)]
-        if self.test_hooks.fail_cleanup_send.replace(false) {
-            return Poll::Ready(Err(state.cleanup.take().unwrap().into_primary()));
-        }
-        #[cfg(test)]
-        let send_result = self.test_hooks.try_send(&self.socket, packet);
-        #[cfg(not(test))]
         let send_result = self.socket.try_send(packet);
         match send_result {
             Ok(_) => return Poll::Ready(Err(state.cleanup.take().unwrap().into_primary())),
@@ -1055,22 +798,6 @@ impl AsyncClient {
         }
     }
 
-    fn clear_peer_close_dscp(&self) -> Result<(), ClientError> {
-        #[cfg(test)]
-        if self.test_hooks.fail_peer_close_dscp.replace(false) {
-            return Err(ClientError::SocketOption {
-                operation: "clear DSCP before close",
-                remote: self.remote,
-                source: io::Error::other("injected peer-close DSCP cleanup failure"),
-            });
-        }
-        clear_dscp_on_tokio_socket(&self.socket, self.remote)
-    }
-
-    fn clear_close_dscp(&self) -> Result<(), ClientError> {
-        clear_dscp_on_tokio_socket(&self.socket, self.remote)
-    }
-
     fn restore_dscp_best_effort(&self, previous_traffic_class: Option<u8>) {
         let _ = match previous_traffic_class {
             Some(traffic_class) => {
@@ -1086,8 +813,6 @@ struct DscpRollback<'a> {
     remote: SocketAddr,
     previous_traffic_class: Option<u8>,
     armed: bool,
-    #[cfg(test)]
-    fail_restore: &'a Cell<bool>,
 }
 
 impl<'a> DscpRollback<'a> {
@@ -1095,15 +820,12 @@ impl<'a> DscpRollback<'a> {
         socket: &'a tokio::net::UdpSocket,
         remote: SocketAddr,
         previous_traffic_class: Option<u8>,
-        #[cfg(test)] fail_restore: &'a Cell<bool>,
     ) -> Self {
         Self {
             socket,
             remote,
             previous_traffic_class,
             armed: true,
-            #[cfg(test)]
-            fail_restore,
         }
     }
 
@@ -1111,14 +833,7 @@ impl<'a> DscpRollback<'a> {
         if !self.armed {
             return Ok(());
         }
-        #[cfg(test)]
-        if self.fail_restore.replace(false) {
-            return Err(ClientError::SocketOption {
-                operation: "restore negotiated DSCP",
-                remote: self.remote,
-                source: io::Error::other("injected DSCP restore failure"),
-            });
-        }
+
         match self.previous_traffic_class {
             Some(traffic_class) => {
                 apply_traffic_class_to_tokio_socket(self.socket, self.remote, traffic_class)?
@@ -1171,6 +886,3 @@ fn poll_readable_until(
         },
     }
 }
-
-#[cfg(test)]
-mod tests;

crates/irtt-client/src/client.rs

@@ -4,12 +4,6 @@ use std::{
     time::{Duration, Instant},
 };
 
-#[cfg(test)]
-use std::cell::Cell;
-
-#[cfg(test)]
-use irtt_proto::{flags, Params, TimestampFields, PROTOCOL_VERSION};
-
 use crate::{
     config::{ClientConfig, RecvBudget},
     error::ClientError,
@@ -24,23 +18,9 @@ use crate::{
     timing::ClientTimestamp,
 };
 
-pub(crate) mod schedule;
-
-use schedule::{instant_abs_diff, ProbeSchedule};
-
-#[derive(Debug, Clone, Copy)]
-enum ProbeScheduleMode {
-    CallerPaced,
-    #[cfg(test)]
-    Managed {
-        scheduled_at: Instant,
-    },
-}
-
 #[derive(Debug)]
 struct PreparedClientOpen {
     machine: PreparedOpenAcceptance,
-    schedule: Option<ProbeSchedule>,
     recv_buffer_len: Option<usize>,
     negotiated_traffic_class: Option<u8>,
     previous_traffic_class: Option<u8>,
@@ -53,60 +33,40 @@ struct PreparedClientOpenFailure {
     machine: PreparedOpenAcceptance,
 }
 
-#[cfg(test)]
-#[derive(Debug, Default)]
-struct ClientTestHooks {
-    fail_open_dscp: Cell<bool>,
-    fail_open_timeout_restore: Cell<bool>,
-    fail_close_event_reserve: Cell<bool>,
-    fail_close_dscp_clear: Cell<bool>,
-    fail_close_send: Cell<bool>,
-    close_reported_len: Cell<Option<usize>>,
-    close_send_attempts: Cell<usize>,
-    close_sent_at: Cell<Option<ClientTimestamp>>,
-    fail_cleanup_send: Cell<bool>,
-    recv_buffer_len_override: Cell<Option<usize>>,
-    fail_dscp_restore: Cell<bool>,
-    last_restored_read_timeout: Cell<Option<Duration>>,
-    prepared_active_session_before_dscp: Cell<bool>,
-    /// Number of subsequent receive attempts that should report
-    /// `io::ErrorKind::Interrupted` before a real receive is attempted.
-    /// Decremented on every injected receive; `0` means inject nothing.
-    inject_recv_interrupted: Cell<usize>,
-}
-
-#[cfg(test)]
-#[derive(Debug, Clone, Copy)]
-pub(crate) struct ProbeSendTimestamps {
-    pub(crate) permission_at: Instant,
-    /// Private pre-send anchor: timeout deadline / kernel TX lower bound.
-    pub(crate) send_anchor: ClientTimestamp,
-    pub(crate) send_call_start: Instant,
-    pub(crate) send_finished_at: Instant,
-    /// Public post-send measurement: RTT / OWD fallback / timer_error.
-    pub(crate) sent_at: ClientTimestamp,
-}
-
-#[cfg(test)]
-use crate::{
-    session::machine::{
-        compute_one_way, compute_rtt, params_from_config, sequence_is_after, sequence_is_before,
-        unix_epoch_ns_i64, update_highest_received,
-    },
-    session::negotiate_params,
-    NegotiatedParams, RunMode, SignedDuration, WarningKind, MAX_UDP_PAYLOAD_LENGTH,
-};
-
 /// Low-level synchronous IRTT client.
 ///
 /// `Client` exposes the protocol steps directly: connect a UDP socket, open a
 /// session, send probes, receive replies, poll timeouts, and close. Callers
 /// that do not need to own this loop can use the unified managed API in
 /// [`crate::managed`] when the `tokio` feature is enabled.
+///
+/// # Example
+///
+/// `Client` is the runtime-free adapter. The caller drives receives and timeout
+/// polling between sends; see the standalone example for a complete loop.
+/// This example type-checks without contacting a server:
+///
+/// ```no_run
+/// use irtt_client::{Client, ClientConfig};
+///
+/// # fn run() -> Result<(), Box<dyn std::error::Error>> {
+/// let mut client = Client::connect(ClientConfig::default())?;
+/// let outcome = client.open()?;
+/// println!("opened: {outcome:?}");
+/// let sent = client.send_probe()?;
+/// println!("sent: {sent:?}");
+/// let received = client.recv_once()?;
+/// println!("received: {received:?}");
+/// let timed_out = client.poll_timeouts()?;
+/// println!("timeouts: {timed_out:?}");
+/// let closed = client.close()?;
+/// println!("closed: {closed:?}");
+/// # Ok(())
+/// # }
+/// ```
 #[derive(Debug)]
 pub struct Client {
     runtime: SessionMachine,
-    schedule: Option<ProbeSchedule>,
     socket: UdpSocket,
     remote: SocketAddr,
     recv_buffer: Vec<u8>,
@@ -118,14 +78,6 @@ pub struct Client {
     /// unnecessary error-queue drains are skipped once it is known there is
     /// nothing to drain.
     tx_timestamping_enabled: bool,
-    #[cfg(test)]
-    test_hooks: ClientTestHooks,
-    #[cfg(test)]
-    probe_reported_len: Option<usize>,
-    #[cfg(test)]
-    probe_send_error: bool,
-    #[cfg(test)]
-    probe_send_timestamps: Option<ProbeSendTimestamps>,
 }
 
 impl Client {
@@ -142,20 +94,11 @@ impl Client {
 
         Ok(Self {
             runtime,
-            schedule: None,
             socket,
             remote,
             recv_buffer: vec![0_u8; recv_buffer_size(false, None)?],
             applied_traffic_class: None,
             tx_timestamping_enabled: false,
-            #[cfg(test)]
-            test_hooks: ClientTestHooks::default(),
-            #[cfg(test)]
-            probe_reported_len: None,
-            #[cfg(test)]
-            probe_send_error: false,
-            #[cfg(test)]
-            probe_send_timestamps: None,
         })
     }
 
@@ -163,12 +106,13 @@ impl Client {
     ///
     /// On success, returns the negotiated open outcome and transitions the
     /// client into either an open probe session or completed no-test state.
-    /// Open attempts use [`ClientConfig::open_timeouts`]. Malformed, unrelated,
-    /// or unauthenticated datagrams are ignored until the current attempt's
-    /// absolute deadline, so one attempt may consume several datagrams without
+    /// Open attempts use [`ClientConfig::open_timeouts`]. Malformed or
+    /// unrelated datagrams are ignored until the current attempt's absolute
+    /// deadline, so one attempt may consume several datagrams without
     /// retransmitting. Silence or ignored traffic eventually produces
-    /// [`ClientError::OpenTimeout`], while authenticated incompatibility remains
-    /// terminal.
+    /// [`ClientError::OpenTimeout`]. A structurally recognizable malformed or
+    /// incompatible Open reply from the connected peer is terminal; when HMAC
+    /// is configured, that recognition additionally requires authentication.
     ///
     /// When a trusted reply allocates a token but later negotiation or socket
     /// preparation fails, the client sends a best-effort cleanup close and
@@ -177,8 +121,9 @@ impl Client {
     pub fn open(&mut self) -> Result<OpenOutcome, ClientError> {
         let result = self.open_transaction();
         if result.is_err() {
-            let _ =
-                self.restore_open_read_timeout(self.runtime.config().socket_config.recv_timeout);
+            let _ = self
+                .socket
+                .set_read_timeout(self.runtime.config().socket_config.recv_timeout);
         }
         result
     }
@@ -188,19 +133,11 @@ impl Client {
     /// The close event means the client has sent its close packet and stopped
     /// tracking the session locally; it is not a server acknowledgement. If the
     /// send fails, the negotiated DSCP is restored best-effort and the session
-    /// and probe schedule remain open.
+    /// remains open.
     pub fn close(&mut self) -> Result<Vec<ClientEvent>, ClientError> {
         let prepared = self.runtime.prepare_close()?;
         let mut events = Vec::new();
-        #[cfg(test)]
-        if self.test_hooks.fail_close_event_reserve.replace(false) {
-            events
-                .try_reserve(usize::MAX)
-                .map_err(|source| ClientError::AllocationFailed {
-                    operation: "close event result",
-                    source,
-                })?;
-        }
+
         events
             .try_reserve(1)
             .map_err(|source| ClientError::AllocationFailed {
@@ -211,51 +148,74 @@ impl Client {
         let expected_bytes = prepared.bytes.len();
 
         self.clear_close_dscp()?;
-        let bytes = match self.send_close_datagram(prepared.bytes) {
+        let bytes = match self.socket.send(prepared.bytes) {
             Ok(bytes) => bytes,
             Err(err) => {
                 self.restore_dscp_best_effort(previous_traffic_class);
                 return Err(ClientError::Socket(err));
             }
         };
-        #[cfg(not(test))]
         let sent_at = ClientTimestamp::now();
-        #[cfg(test)]
-        let sent_at = self
-            .test_hooks
-            .close_sent_at
-            .take()
-            .unwrap_or_else(ClientTimestamp::now);
-        let event = self.runtime.commit_local_close(prepared.commit, sent_at);
-        self.schedule = None;
-        self.applied_traffic_class = None;
 
+        let event = self.runtime.commit_local_close(prepared.commit, sent_at);
+
+        self.applied_traffic_class = None;
         validate_datagram_length(expected_bytes, bytes)?;
         events.push(event);
         Ok(events)
     }
 
-    /// Return the monotonic deadline for the next probe send, if another probe
-    /// is scheduled.
-    pub fn next_send_deadline(&self) -> Option<Instant> {
-        if !self.runtime.is_open() {
-            return None;
-        }
-        self.schedule.as_ref()?.next_send_deadline()
-    }
-
     /// Return the local timeout used to classify pending probes as lost.
     pub fn probe_timeout(&self) -> Duration {
         self.runtime.probe_timeout()
     }
 
-    /// Send one echo probe if the negotiated run is still active.
+    /// Send one echo probe now. The caller owns pacing and run duration.
     ///
-    /// Returns an `EchoSent` event when a probe is sent. Returns an empty event
-    /// list when the run duration has elapsed and no further probe should be
-    /// sent.
+    /// The negotiated interval and duration do not gate low-level sends.
     pub fn send_probe(&mut self) -> Result<Vec<ClientEvent>, ClientError> {
-        self.send_probe_transaction(ProbeScheduleMode::CallerPaced)
+        let remote = self.remote;
+        let (runtime, socket) = (&mut self.runtime, &self.socket);
+        let prepared = runtime.prepare_probe()?;
+        let machine_preflight = runtime.preflight_probe_commit(&prepared)?;
+        let mut events = Vec::new();
+        events
+            .try_reserve(1)
+            .map_err(|source| ClientError::AllocationFailed {
+                operation: "probe event result",
+                source,
+            })?;
+        let expected_bytes = prepared.bytes.len();
+
+        // All fallible probe-commit preflight (timeout deadline arithmetic,
+        // capacity/collision checks already done above) is finalized from
+        // this PRIVATE pre-send anchor, before the socket send. It is not
+        // the public measurement `sent_at` captured further below.
+        let send_anchor = ClientTimestamp::now();
+        let machine_commit = runtime.finalize_probe_commit(machine_preflight, send_anchor)?;
+        let send_call_start = Instant::now();
+
+        let bytes = match socket.send(&prepared.bytes) {
+            Ok(bytes) => bytes,
+            Err(error) => {
+                runtime.invalidate_kernel_tx_correlation();
+                return Err(ClientError::Socket(error));
+            }
+        };
+        let send_finished_at = Instant::now();
+
+        // The public measurement timestamp: paired wall/monotonic sample
+        // captured immediately after the successful socket send completed.
+        // This, not `send_anchor` above, is the RTT/OWD-fallback/timer_error
+        // endpoint. The infallible machine commit below never fails.
+        let sent_at = ClientTimestamp::now();
+        let sent = runtime.commit_probe_sent(machine_commit, sent_at, bytes);
+        let send_call = send_finished_at.saturating_duration_since(send_call_start);
+        validate_datagram_length(expected_bytes, bytes)?;
+        self.drain_tx_timestamps()?;
+
+        events.push(echo_sent_event(remote, sent, send_call));
+        Ok(events)
     }
 
     /// Receive and classify at most one datagram from the socket.
@@ -268,37 +228,6 @@ impl Client {
         self.recv_once_inner()
     }
 
-    /// Receive one datagram into `self.recv_buffer`. In test builds, a
-    /// pending `inject_recv_interrupted` count reports
-    /// `io::ErrorKind::Interrupted` instead of performing a real receive,
-    /// deterministically exercising interrupted-syscall retry behavior.
-    fn recv_datagram_once(&mut self) -> Result<ReceivedDatagram, io::Error> {
-        #[cfg(test)]
-        {
-            let remaining = self.test_hooks.inject_recv_interrupted.get();
-            if remaining > 0 {
-                self.test_hooks.inject_recv_interrupted.set(remaining - 1);
-                return Err(io::Error::from(io::ErrorKind::Interrupted));
-            }
-        }
-        recv_datagram(&self.socket, &mut self.recv_buffer)
-    }
-
-    /// Same as [`Self::recv_datagram_once`], receiving into a caller-supplied
-    /// buffer instead of `self.recv_buffer` (used before the negotiated
-    /// receive buffer size is known, i.e. during Open).
-    fn recv_datagram_once_into(&self, buf: &mut [u8]) -> Result<ReceivedDatagram, io::Error> {
-        #[cfg(test)]
-        {
-            let remaining = self.test_hooks.inject_recv_interrupted.get();
-            if remaining > 0 {
-                self.test_hooks.inject_recv_interrupted.set(remaining - 1);
-                return Err(io::Error::from(io::ErrorKind::Interrupted));
-            }
-        }
-        recv_datagram(&self.socket, buf)
-    }
-
     fn recv_once_inner(&mut self) -> Result<Vec<ClientEvent>, ClientError> {
         let Some(datagram) = self.recv_datagram_retrying_interrupted()? else {
             return Ok(vec![]);
@@ -314,11 +243,8 @@ impl Client {
             datagram.received_at,
             datagram.meta,
         )?;
-        if self.runtime.is_peer_closed() {
-            self.schedule = None;
-            if self.clear_close_dscp().is_ok() {
-                self.applied_traffic_class = None;
-            }
+        if self.runtime.is_peer_closed() && self.clear_close_dscp().is_ok() {
+            self.applied_traffic_class = None;
         }
         Ok(events)
     }
@@ -351,7 +277,7 @@ impl Client {
         let mut timeout_narrowed = false;
 
         let result = loop {
-            match self.recv_datagram_once() {
+            match recv_datagram(&self.socket, &mut self.recv_buffer) {
                 Ok(datagram) => break Ok(Some(datagram)),
                 Err(err)
                     if matches!(
@@ -424,17 +350,19 @@ impl Client {
         self.runtime.poll_timeouts_at(now)
     }
 
-    /// Return whether the current run has completed.
-    ///
-    /// A normal run is complete once no more probes will be sent and all
-    /// pending probes have either replied or timed out. No-test and closed
-    /// sessions are also considered complete.
-    pub fn is_run_complete(&self) -> bool {
-        self.runtime.is_terminal()
-            || self
-                .schedule
-                .as_ref()
-                .is_some_and(|schedule| schedule.is_finished() && self.runtime.pending_is_empty())
+    /// Negotiated parameters of the currently open session.
+    pub fn negotiated_params(&self) -> Option<&crate::NegotiatedParams> {
+        self.runtime.negotiated_params()
+    }
+
+    /// Earliest timeout deadline among probes still awaiting a reply.
+    pub fn next_probe_timeout_deadline(&self) -> Option<Instant> {
+        self.runtime.next_probe_timeout_deadline()
+    }
+
+    /// Whether any sent probes still await a reply or timeout.
+    pub fn has_pending_probes(&self) -> bool {
+        !self.runtime.pending_is_empty()
     }
 
     /// Return whether the session was closed by a peer close-flagged reply.
@@ -447,123 +375,6 @@ impl Client {
         self.runtime.is_peer_closed()
     }
 
-    #[cfg(test)]
-    pub(crate) fn send_managed_probe(
-        &mut self,
-        scheduled_at: Instant,
-    ) -> Result<Vec<ClientEvent>, ClientError> {
-        self.send_probe_transaction(ProbeScheduleMode::Managed { scheduled_at })
-    }
-
-    fn send_probe_transaction(
-        &mut self,
-        mode: ProbeScheduleMode,
-    ) -> Result<Vec<ClientEvent>, ClientError> {
-        self.runtime.ensure_open()?;
-        #[cfg(test)]
-        let test_timestamps = self.probe_send_timestamps.take();
-        #[cfg(test)]
-        let fail_send = std::mem::take(&mut self.probe_send_error);
-        let remote = self.remote;
-        let (runtime, schedule, socket) = (&mut self.runtime, &mut self.schedule, &self.socket);
-        let schedule = schedule
-            .as_mut()
-            .expect("open sessions always have a probe schedule");
-        #[cfg(not(test))]
-        let permission_at = Instant::now();
-        #[cfg(test)]
-        let permission_at = test_timestamps
-            .map(|timestamps| timestamps.permission_at)
-            .unwrap_or_else(Instant::now);
-        if !schedule.permit_probe_at(permission_at) {
-            return Ok(Vec::new());
-        }
-
-        let Some(prepared) = runtime.prepare_probe()? else {
-            return Ok(Vec::new());
-        };
-        let machine_preflight = runtime.preflight_probe_commit(&prepared)?;
-        let schedule_commit = match mode {
-            ProbeScheduleMode::CallerPaced => {
-                schedule.preflight_caller_commit(machine_preflight.next_packets_sent)?
-            }
-            #[cfg(test)]
-            ProbeScheduleMode::Managed { scheduled_at } => {
-                schedule.preflight_managed_commit(scheduled_at, permission_at)?
-            }
-        };
-        let mut events = Vec::new();
-        events
-            .try_reserve(1)
-            .map_err(|source| ClientError::AllocationFailed {
-                operation: "probe event result",
-                source,
-            })?;
-
-        let expected_bytes = prepared.bytes.len();
-        let scheduled_at = schedule_commit.scheduled_at;
-        #[cfg(test)]
-        let reported_bytes = self.probe_reported_len.take();
-        // All fallible probe-commit preflight (timeout deadline arithmetic,
-        // capacity/collision checks already done above) is finalized from
-        // this PRIVATE pre-send anchor, before the socket send. It is not
-        // the public measurement `sent_at` captured further below.
-        #[cfg(not(test))]
-        let send_anchor = ClientTimestamp::now();
-        #[cfg(test)]
-        let send_anchor = test_timestamps
-            .map(|timestamps| timestamps.send_anchor)
-            .unwrap_or_else(ClientTimestamp::now);
-        let machine_commit = runtime.finalize_probe_commit(machine_preflight, send_anchor)?;
-        #[cfg(not(test))]
-        let send_call_start = Instant::now();
-        #[cfg(test)]
-        let send_call_start = test_timestamps
-            .map(|timestamps| timestamps.send_call_start)
-            .unwrap_or_else(Instant::now);
-        #[cfg(test)]
-        if fail_send {
-            return Err(ClientError::Socket(io::Error::other(
-                "injected probe send failure",
-            )));
-        }
-        let bytes = socket.send(&prepared.bytes)?;
-        #[cfg(not(test))]
-        let send_finished_at = Instant::now();
-        #[cfg(test)]
-        let send_finished_at = test_timestamps
-            .map(|timestamps| timestamps.send_finished_at)
-            .unwrap_or_else(Instant::now);
-        // The public measurement timestamp: paired wall/monotonic sample
-        // captured immediately after the successful socket send completed.
-        // This, not `send_anchor` above, is the RTT/OWD-fallback/timer_error
-        // endpoint. The infallible machine/schedule commit below never fails.
-        #[cfg(not(test))]
-        let sent_at = ClientTimestamp::now();
-        #[cfg(test)]
-        let sent_at = test_timestamps
-            .map(|timestamps| timestamps.sent_at)
-            .unwrap_or_else(ClientTimestamp::now);
-        let sent = runtime.commit_probe_sent(machine_commit, sent_at, bytes);
-        schedule.commit(schedule_commit);
-
-        let send_call = send_finished_at.saturating_duration_since(send_call_start);
-        let timer_error = instant_abs_diff(sent_at.mono, scheduled_at);
-        #[cfg(test)]
-        let bytes = reported_bytes.unwrap_or(bytes);
-        validate_datagram_length(expected_bytes, bytes)?;
-        self.drain_tx_timestamps()?;
-
-        events.push(echo_sent_event(
-            remote,
-            sent,
-            send_call,
-            scheduled_at,
-            timer_error,
-        ));
-        Ok(events)
-    }
-
     fn open_transaction(&mut self) -> Result<OpenOutcome, ClientError> {
         let request = self.runtime.prepare_open_request()?;
         let mut buf = [0_u8; MAX_OPEN_PACKET_SIZE];
@@ -587,7 +398,7 @@ impl Client {
                 }
                 self.socket.set_read_timeout(Some(remaining))?;
 
-                let datagram = match self.recv_datagram_once_into(&mut buf) {
+                let datagram = match recv_datagram(&self.socket, &mut buf) {
                     Ok(datagram) => datagram,
                     // WouldBlock/TimedOut mean the attempt's own deadline
                     // elapsed; Interrupted (EINTR) means the syscall was
@@ -630,7 +441,7 @@ impl Client {
                         return Err(failure.primary);
                     }
                 };
-                let prepared = match self.prepare_client_open(machine, datagram.received_at) {
+                let prepared = match self.prepare_client_open(machine) {
                     Ok(prepared) => prepared,
                     Err(failure) => {
                         self.send_cleanup_close_best_effort(failure.machine.cleanup_close_packet());
@@ -647,32 +458,21 @@ impl Client {
     fn prepare_client_open(
         &self,
         machine: PreparedOpenAcceptance,
-        opened_at: ClientTimestamp,
     ) -> Result<PreparedClientOpen, Box<PreparedClientOpenFailure>> {
         let Some(negotiated) = machine.normal_negotiated() else {
             return Ok(PreparedClientOpen {
                 machine,
-                schedule: None,
                 recv_buffer_len: None,
                 negotiated_traffic_class: None,
                 previous_traffic_class: self.applied_traffic_class,
                 post_open_recv_timeout: self.runtime.config().socket_config.recv_timeout,
             });
         };
-        let schedule = match ProbeSchedule::new(opened_at.mono, negotiated) {
-            Ok(schedule) => schedule,
-            Err(primary) => return Err(Box::new(PreparedClientOpenFailure { primary, machine })),
-        };
         let recv_buffer_len = match recv_buffer_size(self.runtime.has_hmac(), Some(negotiated)) {
             Ok(size) => size,
             Err(primary) => return Err(Box::new(PreparedClientOpenFailure { primary, machine })),
         };
-        #[cfg(test)]
-        let recv_buffer_len = self
-            .test_hooks
-            .recv_buffer_len_override
-            .get()
-            .unwrap_or(recv_buffer_len);
+
         let negotiated_traffic_class = match u8::try_from(negotiated.params.dscp) {
             Ok(traffic_class) => traffic_class,
             Err(_) => {
@@ -687,7 +487,6 @@ impl Client {
 
         Ok(PreparedClientOpen {
             machine,
-            schedule: Some(schedule),
             recv_buffer_len: Some(recv_buffer_len),
             negotiated_traffic_class: Some(negotiated_traffic_class),
             previous_traffic_class: self.applied_traffic_class,
@@ -701,7 +500,6 @@ impl Client {
     ) -> Result<OpenOutcome, ClientError> {
         let PreparedClientOpen {
             machine,
-            schedule,
             recv_buffer_len,
             negotiated_traffic_class,
             previous_traffic_class,
@@ -722,17 +520,15 @@ impl Client {
             }
             self.recv_buffer.resize(recv_buffer_len, 0);
 
-            #[cfg(test)]
-            self.test_hooks
-                .prepared_active_session_before_dscp
-                .set(machine.has_prepared_active_session());
-            if let Err(primary) = self.apply_open_dscp(negotiated_traffic_class) {
+            if let Err(primary) =
+                apply_traffic_class_to_socket(&self.socket, self.remote, negotiated_traffic_class)
+            {
                 self.recv_buffer.truncate(previous_len);
                 self.restore_dscp_best_effort(previous_traffic_class);
                 self.send_cleanup_close_best_effort(machine.cleanup_close_packet());
                 return Err(primary);
             }
-            if let Err(source) = self.restore_open_read_timeout(post_open_recv_timeout) {
+            if let Err(source) = self.socket.set_read_timeout(post_open_recv_timeout) {
                 let primary = ClientError::ReadTimeoutRestore { source };
                 self.recv_buffer.truncate(previous_len);
                 self.restore_dscp_best_effort(previous_traffic_class);
@@ -741,17 +537,16 @@ impl Client {
             }
 
             let outcome = self.runtime.commit_open(machine);
-            self.schedule = schedule;
+
             self.applied_traffic_class = Some(negotiated_traffic_class);
             self.tx_timestamping_enabled = try_enable_tx_timestamping(&self.socket);
             Ok(outcome)
         } else {
-            debug_assert!(schedule.is_none());
-            if let Err(source) = self.restore_open_read_timeout(post_open_recv_timeout) {
+            if let Err(source) = self.socket.set_read_timeout(post_open_recv_timeout) {
                 return Err(ClientError::ReadTimeoutRestore { source });
             }
             let outcome = self.runtime.commit_open(machine);
-            self.schedule = None;
+
             self.applied_traffic_class = None;
             self.tx_timestamping_enabled = try_enable_tx_timestamping(&self.socket);
             Ok(outcome)
@@ -776,10 +571,6 @@ impl Client {
     }
 
     fn restore_dscp_best_effort(&self, previous_traffic_class: Option<u8>) {
-        #[cfg(test)]
-        if self.test_hooks.fail_dscp_restore.replace(false) {
-            return;
-        }
         let _ = match previous_traffic_class {
             Some(traffic_class) => {
                 apply_traffic_class_to_socket(&self.socket, self.remote, traffic_class)
@@ -789,85 +580,29 @@ impl Client {
     }
 
     fn clear_close_dscp(&self) -> Result<(), ClientError> {
-        #[cfg(test)]
-        if self.test_hooks.fail_close_dscp_clear.replace(false) {
-            return Err(ClientError::SocketOption {
-                operation: "clear negotiated DSCP",
-                remote: self.remote,
-                source: io::Error::other("injected negotiated DSCP clear failure"),
-            });
-        }
         clear_dscp_on_socket(&self.socket, self.remote)
     }
 
     fn send_cleanup_close_best_effort(&self, packet: Option<&[u8]>) {
         if let Some(packet) = packet {
-            #[cfg(test)]
-            if self.test_hooks.fail_cleanup_send.replace(false) {
-                return;
-            }
             let _ = self.socket.send(packet);
         }
     }
-
-    fn apply_open_dscp(&self, traffic_class: u8) -> Result<(), ClientError> {
-        #[cfg(test)]
-        if self.test_hooks.fail_open_dscp.replace(false) {
-            return Err(ClientError::SocketOption {
-                operation: "set negotiated DSCP",
-                remote: self.remote,
-                source: io::Error::other("injected negotiated DSCP failure"),
-            });
-        }
-        apply_traffic_class_to_socket(&self.socket, self.remote, traffic_class)
-    }
-
-    fn restore_open_read_timeout(&self, timeout: Option<Duration>) -> io::Result<()> {
-        #[cfg(test)]
-        self.test_hooks.last_restored_read_timeout.set(timeout);
-        #[cfg(test)]
-        if self.test_hooks.fail_open_timeout_restore.replace(false) {
-            return Err(io::Error::other(
-                "injected configured read timeout restoration failure",
-            ));
-        }
-        self.socket.set_read_timeout(timeout)
-    }
-
-    fn send_close_datagram(&self, packet: &[u8]) -> io::Result<usize> {
-        #[cfg(test)]
-        {
-            self.test_hooks
-                .close_send_attempts
-                .set(self.test_hooks.close_send_attempts.get() + 1);
-            if self.test_hooks.fail_close_send.replace(false) {
-                return Err(io::Error::other("injected close send failure"));
-            }
-        }
-        let bytes = self.socket.send(packet)?;
-        #[cfg(test)]
-        if let Some(reported) = self.test_hooks.close_reported_len.take() {
-            return Ok(reported);
-        }
-        Ok(bytes)
-    }
 }
 
 pub(crate) fn echo_sent_event(
     remote: SocketAddr,
     sent: ProbeSent,
     send_call: Duration,
-    scheduled_at: Instant,
-    timer_error: Duration,
 ) -> ClientEvent {
     ClientEvent::EchoSent {
         seq: sent.seq,
         remote,
-        scheduled_at,
+        scheduled_at: None,
         sent_at: sent.sent_at,
         bytes: sent.bytes,
         send_call,
-        timer_error,
+        timer_error: None,
     }
 }
 
@@ -878,47 +613,3 @@ pub(crate) fn validate_datagram_length(expected: usize, actual: usize) -> Result
         Err(ClientError::DatagramLengthMismatch { expected, actual })
     }
 }
-
-#[cfg(test)]
-impl Client {
-    fn send_probe_at(
-        &mut self,
-        timestamps: ProbeSendTimestamps,
-    ) -> Result<Vec<ClientEvent>, ClientError> {
-        self.probe_send_timestamps = Some(timestamps);
-        self.send_probe()
-    }
-
-    fn send_managed_probe_at(
-        &mut self,
-        scheduled_at: Instant,
-        timestamps: ProbeSendTimestamps,
-    ) -> Result<Vec<ClientEvent>, ClientError> {
-        self.probe_send_timestamps = Some(timestamps);
-        self.send_managed_probe(scheduled_at)
-    }
-}
-
-#[cfg(test)]
-fn bounded_receive_timeout(
-    deadline: Option<Instant>,
-    configured_timeout: Option<Duration>,
-    max_wait: Duration,
-    now: Instant,
-) -> Option<Duration> {
-    if max_wait.is_zero() {
-        return None;
-    }
-    let mut timeout = configured_timeout.unwrap_or(max_wait).min(max_wait);
-    if let Some(deadline) = deadline {
-        let remaining = deadline.checked_duration_since(now)?;
-        if remaining.is_zero() {
-            return None;
-        }
-        timeout = timeout.min(remaining);
-    }
-    (!timeout.is_zero()).then_some(timeout)
-}
-
-#[cfg(test)]
-mod tests;

crates/irtt-client/src/client/schedule.rs

@@ -1,318 +0,0 @@
-use std::time::{Duration, Instant};
-
-use crate::{error::ClientError, session::NegotiatedParams};
-
-#[derive(Debug)]
-pub(crate) struct ProbeSchedule {
-    start_at: Instant,
-    end_at: Option<Instant>,
-    interval: Duration,
-    next_send_at: Option<Instant>,
-}
-
-#[derive(Debug)]
-pub(crate) struct ScheduleCommit {
-    pub(crate) scheduled_at: Instant,
-    pub(crate) next_send_at: Option<Instant>,
-}
-
-impl ProbeSchedule {
-    pub(crate) fn new(
-        start_at: Instant,
-        negotiated: &NegotiatedParams,
-    ) -> Result<Self, ClientError> {
-        let interval_ns = u64::try_from(negotiated.params.interval_ns)
-            .expect("validated positive negotiated interval");
-        let interval = Duration::from_nanos(interval_ns);
-        let end_at = if negotiated.params.duration_ns > 0 {
-            let duration_ns = u64::try_from(negotiated.params.duration_ns)
-                .expect("validated positive negotiated duration");
-            Some(
-                start_at
-                    .checked_add(Duration::from_nanos(duration_ns))
-                    .ok_or_else(|| ClientError::NegotiationRejected {
-                        reason: "duration is too large to schedule".to_owned(),
-                    })?,
-            )
-        } else {
-            None
-        };
-
-        Ok(Self {
-            start_at,
-            end_at,
-            interval,
-            next_send_at: Some(start_at),
-        })
-    }
-
-    pub(crate) fn next_send_deadline(&self) -> Option<Instant> {
-        self.next_send_at
-    }
-
-    #[cfg(feature = "tokio")]
-    pub(crate) fn interval(&self) -> Duration {
-        self.interval
-    }
-
-    pub(crate) fn permit_probe_at(&mut self, now: Instant) -> bool {
-        if self.next_send_at.is_none() {
-            return false;
-        }
-        if self.end_at.is_some_and(|end| now >= end) {
-            self.next_send_at = None;
-            return false;
-        }
-        true
-    }
-
-    pub(crate) fn preflight_caller_commit(
-        &self,
-        next_packets_sent: u64,
-    ) -> Result<ScheduleCommit, ClientError> {
-        let scheduled_at = self
-            .next_send_at
-            .expect("a caller schedule commit requires a permitted probe");
-        let interval_ns =
-            u64::try_from(self.interval.as_nanos()).map_err(|_| ClientError::DurationOverflow)?;
-        let next_send_at = next_probe_deadline(self.start_at, interval_ns, next_packets_sent)?;
-        Ok(self.finish_commit(scheduled_at, next_send_at))
-    }
-
-    #[cfg(any(feature = "tokio", test))]
-    pub(crate) fn preflight_managed_commit(
-        &self,
-        scheduled_at: Instant,
-        permission_at: Instant,
-    ) -> Result<ScheduleCommit, ClientError> {
-        let (scheduled_at, next_send_at, _) =
-            advance_cadence(scheduled_at, self.interval, permission_at)?;
-        Ok(self.finish_commit(scheduled_at, next_send_at))
-    }
-
-    pub(crate) fn commit(&mut self, commit: ScheduleCommit) {
-        self.next_send_at = commit.next_send_at;
-    }
-
-    pub(crate) fn is_finished(&self) -> bool {
-        self.next_send_at.is_none()
-    }
-
-    fn finish_commit(&self, scheduled_at: Instant, next_send_at: Instant) -> ScheduleCommit {
-        ScheduleCommit {
-            scheduled_at,
-            next_send_at: if self.end_at.is_some_and(|end| next_send_at >= end) {
-                None
-            } else {
-                Some(next_send_at)
-            },
-        }
-    }
-}
-
-fn next_probe_deadline(
-    start: Instant,
-    interval_ns: u64,
-    packets_sent: u64,
-) -> Result<Instant, ClientError> {
-    let offset_ns = interval_ns
-        .checked_mul(packets_sent)
-        .ok_or(ClientError::DurationOverflow)?;
-    start
-        .checked_add(Duration::from_nanos(offset_ns))
-        .ok_or(ClientError::DurationOverflow)
-}
-
-#[cfg(any(feature = "tokio", test))]
-pub(crate) fn advance_cadence(
-    deadline: Instant,
-    interval: Duration,
-    now: Instant,
-) -> Result<(Instant, Instant, u128), ClientError> {
-    if interval.is_zero() {
-        return Err(ClientError::InvalidConfig {
-            reason: "probe interval must be greater than zero".to_owned(),
-        });
-    }
-
-    let elapsed_slots = now
-        .checked_duration_since(deadline)
-        .map_or(0, |elapsed| elapsed.as_nanos() / interval.as_nanos());
-    let scheduled_offset = duration_from_nanos(
-        interval
-            .as_nanos()
-            .checked_mul(elapsed_slots)
-            .ok_or(ClientError::DurationOverflow)?,
-    )?;
-    let next_offset = duration_from_nanos(
-        interval
-            .as_nanos()
-            .checked_mul(
-                elapsed_slots
-                    .checked_add(1)
-                    .ok_or(ClientError::DurationOverflow)?,
-            )
-            .ok_or(ClientError::DurationOverflow)?,
-    )?;
-    let scheduled_at = deadline
-        .checked_add(scheduled_offset)
-        .ok_or(ClientError::DurationOverflow)?;
-    let next_at = deadline
-        .checked_add(next_offset)
-        .ok_or(ClientError::DurationOverflow)?;
-    Ok((scheduled_at, next_at, elapsed_slots))
-}
-
-#[cfg(any(feature = "tokio", test))]
-fn duration_from_nanos(nanos: u128) -> Result<Duration, ClientError> {
-    const NANOS_PER_SECOND: u128 = 1_000_000_000;
-    let seconds =
-        u64::try_from(nanos / NANOS_PER_SECOND).map_err(|_| ClientError::DurationOverflow)?;
-    let subsec_nanos = u32::try_from(nanos % NANOS_PER_SECOND)
-        .expect("nanosecond remainder is always less than one second");
-    Ok(Duration::new(seconds, subsec_nanos))
-}
-
-pub(crate) fn instant_abs_diff(left: Instant, right: Instant) -> Duration {
-    left.checked_duration_since(right)
-        .or_else(|| right.checked_duration_since(left))
-        .unwrap_or(Duration::ZERO)
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use irtt_proto::Params;
-
-    fn negotiated(interval_ns: i64, duration_ns: i64) -> NegotiatedParams {
-        NegotiatedParams {
-            params: Params {
-                interval_ns,
-                duration_ns,
-                ..Params::default()
-            },
-            restrictions: Vec::new(),
-        }
-    }
-
-    #[test]
-    fn initial_deadline_is_the_opening_time() {
-        let opened_at = Instant::now();
-
-        let schedule = ProbeSchedule::new(opened_at, &negotiated(10_000_000, 0)).unwrap();
-
-        assert_eq!(schedule.next_send_deadline(), Some(opened_at));
-        assert!(!schedule.is_finished());
-    }
-
-    #[test]
-    fn caller_preflight_keeps_absolute_cadence_without_mutation() {
-        let start = Instant::now();
-        let schedule = ProbeSchedule::new(start, &negotiated(10_000_000, 0)).unwrap();
-
-        let commit = schedule.preflight_caller_commit(3).unwrap();
-
-        assert_eq!(commit.scheduled_at, start);
-        assert_eq!(commit.next_send_at, Some(start + Duration::from_millis(30)));
-        assert_eq!(schedule.next_send_deadline(), Some(start));
-    }
-
-    #[test]
-    fn caller_commit_advances_exactly_one_cadence_slot() {
-        let start = Instant::now();
-        let mut schedule = ProbeSchedule::new(start, &negotiated(10_000_000, 0)).unwrap();
-
-        let commit = schedule.preflight_caller_commit(1).unwrap();
-        assert_eq!(schedule.next_send_deadline(), Some(start));
-
-        schedule.commit(commit);
-        assert_eq!(
-            schedule.next_send_deadline(),
-            Some(start + Duration::from_millis(10))
-        );
-    }
-
-    #[test]
-    fn finite_duration_uses_an_exclusive_end_boundary() {
-        let start = Instant::now();
-        let mut schedule = ProbeSchedule::new(start, &negotiated(10_000_000, 20_000_000)).unwrap();
-
-        let first = schedule.preflight_caller_commit(1).unwrap();
-        schedule.commit(first);
-        assert_eq!(
-            schedule.next_send_deadline(),
-            Some(start + Duration::from_millis(10))
-        );
-
-        let second = schedule.preflight_caller_commit(2).unwrap();
-        schedule.commit(second);
-
-        assert!(schedule.is_finished());
-        assert_eq!(schedule.next_send_deadline(), None);
-        assert!(!schedule.permit_probe_at(start + Duration::from_millis(20)));
-    }
-
-    #[test]
-    fn permit_at_exclusive_end_finishes_schedule_without_a_send() {
-        let start = Instant::now();
-        let mut schedule = ProbeSchedule::new(start, &negotiated(10_000_000, 20_000_000)).unwrap();
-
-        assert!(!schedule.permit_probe_at(start + Duration::from_millis(20)));
-        assert!(schedule.is_finished());
-        assert_eq!(schedule.next_send_deadline(), None);
-    }
-
-    #[test]
-    fn managed_preflight_skips_missed_slots_without_mutation() {
-        let start = Instant::now();
-        let schedule = ProbeSchedule::new(start, &negotiated(10_000_000, 0)).unwrap();
-        let sent_at = start + Duration::from_millis(45);
-
-        let commit = schedule.preflight_managed_commit(start, sent_at).unwrap();
-
-        assert_eq!(commit.scheduled_at, start + Duration::from_millis(40));
-        assert_eq!(commit.next_send_at, Some(start + Duration::from_millis(50)));
-        assert_eq!(schedule.next_send_deadline(), Some(start));
-    }
-
-    #[test]
-    fn delayed_managed_commit_does_not_replay_catch_up_slots() {
-        let start = Instant::now();
-        let mut schedule = ProbeSchedule::new(start, &negotiated(10_000_000, 0)).unwrap();
-        let delayed_send = start + Duration::from_millis(45);
-
-        let commit = schedule
-            .preflight_managed_commit(start, delayed_send)
-            .unwrap();
-        schedule.commit(commit);
-
-        assert_eq!(
-            schedule.next_send_deadline(),
-            Some(start + Duration::from_millis(50))
-        );
-        assert!(schedule.next_send_deadline().unwrap() > delayed_send);
-    }
-
-    #[test]
-    fn deadline_arithmetic_overflow_is_detected_before_commit() {
-        let start = Instant::now();
-        let schedule = ProbeSchedule::new(start, &negotiated(2, 0)).unwrap();
-
-        assert!(matches!(
-            schedule.preflight_caller_commit(u64::MAX),
-            Err(ClientError::DurationOverflow)
-        ));
-        assert_eq!(schedule.next_send_deadline(), Some(start));
-    }
-
-    #[test]
-    fn timer_error_is_adapter_owned() {
-        let scheduled_at = Instant::now();
-        let sent_at = scheduled_at + Duration::from_millis(7);
-
-        assert_eq!(
-            instant_abs_diff(sent_at, scheduled_at),
-            Duration::from_millis(7)
-        );
-    }
-}

crates/irtt-client/src/client/tests/dscp.rs

@@ -1,208 +0,0 @@
-use super::*;
-use crate::socket_options::socket_traffic_class;
-
-#[test]
-#[cfg(not(any(
-    target_os = "fuchsia",
-    target_os = "redox",
-    target_os = "solaris",
-    target_os = "illumos",
-    target_os = "haiku",
-)))]
-fn normal_open_applies_negotiated_traffic_class_after_open_and_close_clears_it() {
-    let mut params = default_params();
-    // Raw wire TOS/Traffic Class byte for DSCP codepoint 46 (EF): a
-    // compliant server echoes back the raw byte it received, unchanged.
-    params.dscp = 184;
-    let server = start_fake_server(move |socket, tx| {
-        let (_, peer) = recv_request(&socket, &tx);
-        let reply = open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, None);
-        socket.send_to(&reply, peer).unwrap();
-        let _ = recv_request(&socket, &tx);
-    });
-    let mut config = default_test_config(server.addr);
-    config.dscp = 46;
-    let mut client = Client::connect(config).unwrap();
-
-    assert_eq!(
-        socket_traffic_class(&client.socket, client.remote).unwrap() & 0xfc,
-        0
-    );
-    assert_open_started(client.open().unwrap());
-    assert_eq!(
-        socket_traffic_class(&client.socket, client.remote).unwrap() & 0xfc,
-        184
-    );
-
-    client.close().unwrap();
-    assert_eq!(
-        socket_traffic_class(&client.socket, client.remote).unwrap(),
-        0
-    );
-    server.join();
-}
-
-#[test]
-#[cfg(not(any(
-    target_os = "fuchsia",
-    target_os = "redox",
-    target_os = "solaris",
-    target_os = "illumos",
-    target_os = "haiku",
-)))]
-fn normal_open_uses_negotiated_traffic_class_not_requested_dscp() {
-    let mut returned = default_params();
-    returned.dscp = 0;
-    let server = open_success_server(returned);
-
-    let mut config = default_test_config(server.addr);
-    config.dscp = 46;
-    config.negotiation_policy = NegotiationPolicy::Loose;
-    let mut client = Client::connect(config).unwrap();
-
-    let negotiated = assert_open_started(client.open().unwrap());
-    assert_eq!(negotiated.params.dscp, 0);
-    assert_eq!(
-        negotiated.restrictions,
-        vec![crate::NegotiationRestriction::DscpChanged {
-            requested: 46,
-            negotiated: 0,
-        }]
-    );
-    assert_eq!(
-        socket_traffic_class(&client.socket, client.remote).unwrap(),
-        0
-    );
-    server.join();
-}
-
-#[test]
-#[cfg(not(any(
-    target_os = "fuchsia",
-    target_os = "redox",
-    target_os = "solaris",
-    target_os = "illumos",
-    target_os = "haiku",
-)))]
-fn failed_close_send_restores_negotiated_traffic_class_and_keeps_session_open() {
-    let mut params = default_params();
-    // Raw wire TOS/Traffic Class byte for DSCP codepoint 46 (EF).
-    params.dscp = 184;
-    let server = start_fake_server(move |socket, tx| {
-        let (_, peer) = recv_request(&socket, &tx);
-        socket
-            .send_to(
-                &open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, None),
-                peer,
-            )
-            .unwrap();
-        let _ = recv_request(&socket, &tx);
-    });
-    let mut config = default_test_config(server.addr);
-    config.dscp = 46;
-    let mut client = Client::connect(config).unwrap();
-    assert_open_started(client.open().unwrap());
-    client.test_hooks.fail_close_send.set(true);
-
-    let error = client.close().unwrap_err();
-
-    assert!(matches!(error, ClientError::Socket(_)));
-    assert!(client.runtime.is_open());
-    assert!(client.schedule.is_some());
-    assert_eq!(client.applied_traffic_class, Some(184));
-    assert_eq!(
-        socket_traffic_class(&client.socket, client.remote).unwrap() & 0xfc,
-        184
-    );
-    client.close().unwrap();
-    server.join();
-}
-
-#[test]
-fn failed_close_keeps_send_error_primary_when_dscp_restoration_also_fails() {
-    let params = default_params();
-    let server = start_fake_server(move |socket, tx| {
-        let (_, peer) = recv_request(&socket, &tx);
-        socket
-            .send_to(
-                &open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, None),
-                peer,
-            )
-            .unwrap();
-        let _ = recv_request(&socket, &tx);
-    });
-    let mut client = Client::connect(default_test_config(server.addr)).unwrap();
-    assert_open_started(client.open().unwrap());
-    client.test_hooks.fail_close_send.set(true);
-    client.test_hooks.fail_dscp_restore.set(true);
-
-    let error = client.close().unwrap_err();
-
-    assert!(matches!(error, ClientError::Socket(_)));
-    assert!(error.to_string().contains("injected close send failure"));
-    assert!(client.runtime.is_open());
-    assert!(client.schedule.is_some());
-    assert_eq!(client.applied_traffic_class, Some(0));
-    client.close().unwrap();
-    server.join();
-}
-
-#[test]
-#[cfg(not(any(
-    target_os = "fuchsia",
-    target_os = "redox",
-    target_os = "solaris",
-    target_os = "illumos",
-    target_os = "haiku",
-)))]
-fn authenticated_peer_close_clears_schedule_and_negotiated_traffic_class() {
-    let mut params = default_params();
-    // Raw wire TOS/Traffic Class byte for DSCP codepoint 46 (EF).
-    params.dscp = 184;
-    let server = start_fake_server(move |socket, tx| {
-        let (_, peer) = recv_request(&socket, &tx);
-        socket
-            .send_to(
-                &open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, None),
-                peer,
-            )
-            .unwrap();
-        let (request, _) = recv_request(&socket, &tx);
-        let seq = u32::from_le_bytes(request[12..16].try_into().unwrap());
-        socket
-            .send_to(
-                &echo_reply_packet_with_flags(
-                    TOKEN,
-                    seq,
-                    &params,
-                    &TimestampFields::default(),
-                    None,
-                    FLAG_REPLY | flags::FLAG_CLOSE,
-                ),
-                peer,
-            )
-            .unwrap();
-    });
-    let mut config = default_test_config(server.addr);
-    config.dscp = 46;
-    let mut client = Client::connect(config).unwrap();
-    assert_open_started(client.open().unwrap());
-    client.send_probe().unwrap();
-
-    let events = client.recv_once().unwrap();
-
-    assert!(matches!(
-        events.as_slice(),
-        [
-            ClientEvent::EchoReply { .. },
-            ClientEvent::SessionClosed { .. }
-        ]
-    ));
-    assert!(client.schedule.is_none());
-    assert_eq!(client.applied_traffic_class, None);
-    assert_eq!(
-        socket_traffic_class(&client.socket, client.remote).unwrap(),
-        0
-    );
-    server.join();
-}

crates/irtt-client/src/client/tests/hmac.rs

@@ -1,225 +0,0 @@
-use super::*;
-
-#[test]
-fn hmac_open_success() {
-    let key = b"secret".to_vec();
-    let mut config = default_test_config(SocketAddr::from(([127, 0, 0, 1], 1)));
-    config.hmac_key = Some(key.clone());
-    let params = params_from_config(&config).unwrap();
-    let server = start_fake_server(move |socket, tx| {
-        let (request, peer) = recv_request(&socket, &tx);
-        verify_packet_hmac(&key, &request).unwrap();
-        let reply = open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, Some(&key));
-        socket.send_to(&reply, peer).unwrap();
-    });
-    config.server_addr = server.addr.to_string();
-    let mut client = Client::connect(config).unwrap();
-    assert_open_started(client.open().unwrap());
-    server.join();
-}
-
-#[test]
-fn hmac_open_ignores_missing_hmac_before_valid_reply() {
-    let key = b"secret".to_vec();
-    let mut config = default_test_config(SocketAddr::from(([127, 0, 0, 1], 1)));
-    config.hmac_key = Some(key.clone());
-    let params = params_from_config(&config).unwrap();
-    let server = start_fake_server(move |socket, tx| {
-        let (_, peer) = recv_request(&socket, &tx);
-        let missing = open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, None);
-        let valid = open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, Some(&key));
-        socket.send_to(&missing, peer).unwrap();
-        socket.send_to(&valid, peer).unwrap();
-    });
-    config.server_addr = server.addr.to_string();
-    let mut client = Client::connect(config).unwrap();
-    assert_open_started(client.open().unwrap());
-    assert_eq!(server.rx.iter().take(1).count(), 1);
-    assert!(server.rx.try_recv().is_err());
-    server.join();
-}
-
-#[test]
-fn hmac_open_ignores_bad_hmac_before_valid_reply() {
-    let key = b"secret".to_vec();
-    let wrong_key = b"wrong".to_vec();
-    let mut config = default_test_config(SocketAddr::from(([127, 0, 0, 1], 1)));
-    config.hmac_key = Some(key.clone());
-    let params = params_from_config(&config).unwrap();
-    let server = start_fake_server(move |socket, tx| {
-        let (_, peer) = recv_request(&socket, &tx);
-        let bad = open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, Some(&wrong_key));
-        let valid = open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, Some(&key));
-        socket.send_to(&bad, peer).unwrap();
-        socket.send_to(&valid, peer).unwrap();
-    });
-    config.server_addr = server.addr.to_string();
-    let mut client = Client::connect(config).unwrap();
-    assert_open_started(client.open().unwrap());
-    assert_eq!(server.rx.iter().take(1).count(), 1);
-    assert!(server.rx.try_recv().is_err());
-    server.join();
-}
-
-#[test]
-fn post_token_hmac_negotiation_failure_sends_authenticated_cleanup_close() {
-    let key = b"secret".to_vec();
-    let mut config = default_test_config(SocketAddr::from(([127, 0, 0, 1], 1)));
-    config.hmac_key = Some(key.clone());
-    let mut returned = params_from_config(&config).unwrap();
-    returned.interval_ns += 1;
-    let server_key = key.clone();
-    let server = start_fake_server(move |socket, tx| {
-        let (_, peer) = recv_request(&socket, &tx);
-        let reply = open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &returned, Some(&server_key));
-        socket.send_to(&reply, peer).unwrap();
-        let _ = recv_request(&socket, &tx);
-    });
-    config.server_addr = server.addr.to_string();
-    let mut client = Client::connect(config).unwrap();
-
-    assert!(matches!(
-        client.open(),
-        Err(ClientError::NegotiationRejected { .. })
-    ));
-    let packets: Vec<_> = server.rx.iter().take(2).collect();
-    let cleanup = &packets[1];
-    assert_eq!(cleanup[3], flags::FLAG_CLOSE | FLAG_HMAC);
-    verify_packet_hmac(&key, cleanup).unwrap();
-    assert_eq!(
-        u64::from_le_bytes(cleanup[4 + HMAC_SIZE..12 + HMAC_SIZE].try_into().unwrap()),
-        TOKEN
-    );
-    server.join();
-}
-
-#[test]
-fn hmac_close_packet_includes_valid_hmac() {
-    let key = b"secret".to_vec();
-    let mut config = default_test_config(SocketAddr::from(([127, 0, 0, 1], 1)));
-    config.hmac_key = Some(key.clone());
-    let params = params_from_config(&config).unwrap();
-    let server_key = key.clone();
-    let server = start_fake_server(move |socket, tx| {
-        let (_, peer) = recv_request(&socket, &tx);
-        let reply = open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, Some(&server_key));
-        socket.send_to(&reply, peer).unwrap();
-        let _ = recv_request(&socket, &tx);
-    });
-    config.server_addr = server.addr.to_string();
-    let mut client = Client::connect(config).unwrap();
-    assert_open_started(client.open().unwrap());
-    client.close().unwrap();
-    let packets: Vec<_> = server.rx.iter().take(2).collect();
-    let close = &packets[1];
-    assert_eq!(close[3], flags::FLAG_CLOSE | FLAG_HMAC);
-    verify_packet_hmac(&key, close).unwrap();
-    assert_eq!(
-        u64::from_le_bytes(close[4 + HMAC_SIZE..12 + HMAC_SIZE].try_into().unwrap()),
-        TOKEN
-    );
-    server.join();
-}
-
-#[test]
-fn bad_hmac_reply_is_dropped() {
-    let key = b"secret".to_vec();
-    let wrong_key = b"wrong".to_vec();
-    let params = default_params();
-    let server_key = key.clone();
-    let server = start_fake_server(move |socket, tx| {
-        let (_, peer) = recv_request(&socket, &tx);
-        let reply = open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, Some(&server_key));
-        socket.send_to(&reply, peer).unwrap();
-
-        socket
-            .set_read_timeout(Some(Duration::from_secs(2)))
-            .unwrap();
-        let mut buf = [0_u8; 2048];
-        if let Ok((size, _)) = socket.recv_from(&mut buf) {
-            tx.send(buf[..size].to_vec()).unwrap();
-            let seq = u32::from_le_bytes(
-                buf[4 + HMAC_SIZE + 8..4 + HMAC_SIZE + 12]
-                    .try_into()
-                    .unwrap(),
-            );
-            let ts = TimestampFields::default();
-            let reply_packet = echo_reply_packet_with_flags(
-                TOKEN,
-                seq,
-                &params,
-                &ts,
-                Some(&wrong_key),
-                FLAG_REPLY | flags::FLAG_CLOSE,
-            );
-            socket.send_to(&reply_packet, peer).unwrap();
-        }
-    });
-    let config = ClientConfig {
-        hmac_key: Some(key),
-        socket_config: crate::SocketConfig {
-            recv_timeout: Some(Duration::from_millis(200)),
-            ..Default::default()
-        },
-        ..default_test_config(server.addr)
-    };
-    let mut client = Client::connect(config).unwrap();
-    assert_open_started(client.open().unwrap());
-    client.send_probe().unwrap();
-    thread::sleep(Duration::from_millis(30));
-    let events = client.recv_once().unwrap();
-    assert_eq!(events.len(), 1);
-    assert!(matches!(&events[0], ClientEvent::Warning { .. }));
-    assert!(!client.is_peer_closed());
-    client.close().unwrap();
-    server.join();
-}
-
-#[test]
-fn hmac_echo_request_reply_works() {
-    let key = b"testkey".to_vec();
-    let params = default_params();
-    let server_key = key.clone();
-    let server = start_fake_server(move |socket, tx| {
-        let (_, peer) = recv_request(&socket, &tx);
-        let reply = open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, Some(&server_key));
-        socket.send_to(&reply, peer).unwrap();
-
-        socket
-            .set_read_timeout(Some(Duration::from_secs(2)))
-            .unwrap();
-        let mut buf = [0_u8; 2048];
-        if let Ok((size, _)) = socket.recv_from(&mut buf) {
-            tx.send(buf[..size].to_vec()).unwrap();
-            verify_packet_hmac(&server_key, &buf[..size]).unwrap();
-            let seq = u32::from_le_bytes(
-                buf[4 + HMAC_SIZE + 8..4 + HMAC_SIZE + 12]
-                    .try_into()
-                    .unwrap(),
-            );
-            let ts = TimestampFields {
-                recv_mono: Some(100),
-                send_mono: Some(200),
-                ..Default::default()
-            };
-            let reply_packet = echo_reply_packet(TOKEN, seq, &params, &ts, Some(&server_key));
-            socket.send_to(&reply_packet, peer).unwrap();
-        }
-    });
-    let config = ClientConfig {
-        hmac_key: Some(key),
-        socket_config: crate::SocketConfig {
-            recv_timeout: Some(Duration::from_millis(200)),
-            ..Default::default()
-        },
-        ..default_test_config(server.addr)
-    };
-    let mut client = Client::connect(config).unwrap();
-    assert_open_started(client.open().unwrap());
-    client.send_probe().unwrap();
-    thread::sleep(Duration::from_millis(50));
-    let events = client.recv_once().unwrap();
-    assert_eq!(events.len(), 1);
-    assert!(matches!(&events[0], ClientEvent::EchoReply { .. }));
-    server.join();
-}

crates/irtt-client/src/client/tests/mod.rs

@@ -1,21 +0,0 @@
-use super::*;
-use crate::config::{NegotiationPolicy, DEFAULT_OPEN_TIMEOUTS};
-use irtt_proto::{
-    flags::FLAG_HMAC, flags::FLAG_OPEN, flags::FLAG_REPLY, verify_packet_hmac, Clock,
-    ReceivedStats, StampAt, HMAC_SIZE, MAGIC,
-};
-use std::{thread, time::SystemTime};
-
-mod support;
-use support::*;
-
-mod close;
-mod config;
-mod dscp;
-mod hmac;
-mod negotiation;
-mod no_test;
-mod open;
-mod probes_replies;
-mod sequence;
-mod ttl;

crates/irtt-client/src/client/tests/negotiation.rs

@@ -1,289 +0,0 @@
-use super::*;
-use crate::NegotiationRestriction;
-
-fn assert_negotiates(
-    requested: &Params,
-    returned: &Params,
-    policy: NegotiationPolicy,
-) -> NegotiatedParams {
-    negotiate_params(requested, returned.clone(), policy)
-        .unwrap_or_else(|err| panic!("expected negotiation success, got {err:?}"))
-}
-
-fn rejection_reason(requested: &Params, returned: &Params, policy: NegotiationPolicy) -> String {
-    match negotiate_params(requested, returned.clone(), policy) {
-        Err(ClientError::NegotiationRejected { reason }) => reason,
-        other => panic!("expected negotiation rejection, got {other:?}"),
-    }
-}
-
-#[test]
-fn strict_negotiation_accepts_identical_params() {
-    let config = ClientConfig::default();
-    let params = params_from_config(&config).unwrap();
-    let negotiated = assert_negotiates(&params, &params, NegotiationPolicy::Strict);
-    assert_eq!(negotiated.params, params);
-    assert!(negotiated.restrictions.is_empty());
-}
-
-#[test]
-fn strict_negotiation_rejects_changed_params() {
-    let config = ClientConfig {
-        dscp: 46,
-        ..ClientConfig::default()
-    };
-    let requested = params_from_config(&config).unwrap();
-    assert_eq!(
-        requested.dscp, 184,
-        "codepoint 46 must become raw wire byte 184"
-    );
-    let mut returned = requested.clone();
-    returned.dscp = 0;
-    assert_eq!(
-        rejection_reason(&requested, &returned, NegotiationPolicy::Strict),
-        NegotiationRestriction::DscpChanged {
-            requested: 46,
-            negotiated: 0,
-        }
-        .message()
-    );
-}
-
-#[test]
-fn loose_negotiation_accepts_server_restricted_params() {
-    let config = ClientConfig::default();
-    let mut requested = params_from_config(&config).unwrap();
-    requested.length = 128;
-    let mut returned = requested.clone();
-    returned.duration_ns /= 2;
-    returned.length = 0;
-    let negotiated = assert_negotiates(&requested, &returned, NegotiationPolicy::Loose);
-    assert_eq!(
-        negotiated.restrictions,
-        vec![
-            NegotiationRestriction::DurationReduced {
-                requested_ns: requested.duration_ns,
-                negotiated_ns: returned.duration_ns,
-            },
-            NegotiationRestriction::LengthReduced {
-                requested: requested.length,
-                negotiated: returned.length,
-            },
-        ]
-    );
-}
-
-#[test]
-fn loose_negotiation_rejects_non_positive_returned_interval() {
-    let config = ClientConfig::default();
-    let requested = params_from_config(&config).unwrap();
-
-    for interval_ns in [0, -1] {
-        let mut returned = requested.clone();
-        returned.interval_ns = interval_ns;
-        assert_eq!(
-            rejection_reason(&requested, &returned, NegotiationPolicy::Loose),
-            "interval must be positive"
-        );
-    }
-}
-
-#[test]
-fn loose_negotiation_accepts_documented_duration_combinations() {
-    let finite_config = ClientConfig::default();
-    let requested_finite = params_from_config(&finite_config).unwrap();
-
-    let returned_same_finite = requested_finite.clone();
-    assert!(assert_negotiates(
-        &requested_finite,
-        &returned_same_finite,
-        NegotiationPolicy::Loose
-    )
-    .restrictions
-    .is_empty());
-
-    let mut returned_shorter_finite = requested_finite.clone();
-    returned_shorter_finite.duration_ns /= 2;
-    assert_eq!(
-        assert_negotiates(
-            &requested_finite,
-            &returned_shorter_finite,
-            NegotiationPolicy::Loose
-        )
-        .restrictions,
-        vec![NegotiationRestriction::DurationReduced {
-            requested_ns: requested_finite.duration_ns,
-            negotiated_ns: returned_shorter_finite.duration_ns,
-        }]
-    );
-
-    let continuous_config = ClientConfig {
-        duration: None,
-        ..ClientConfig::default()
-    };
-    let requested_continuous = params_from_config(&continuous_config).unwrap();
-
-    let returned_continuous = requested_continuous.clone();
-    assert!(assert_negotiates(
-        &requested_continuous,
-        &returned_continuous,
-        NegotiationPolicy::Loose
-    )
-    .restrictions
-    .is_empty());
-
-    let mut returned_finite = requested_continuous.clone();
-    returned_finite.duration_ns = 1_000_000_000;
-    assert_eq!(
-        assert_negotiates(
-            &requested_continuous,
-            &returned_finite,
-            NegotiationPolicy::Loose
-        )
-        .restrictions,
-        vec![NegotiationRestriction::DurationReduced {
-            requested_ns: requested_continuous.duration_ns,
-            negotiated_ns: returned_finite.duration_ns,
-        }]
-    );
-}
-
-#[test]
-fn loose_negotiation_rejects_finite_request_returned_continuous() {
-    let config = ClientConfig::default();
-    let requested = params_from_config(&config).unwrap();
-    let mut returned = requested.clone();
-    returned.duration_ns = 0;
-
-    assert_eq!(
-        rejection_reason(&requested, &returned, NegotiationPolicy::Loose),
-        "server returned continuous duration for finite request"
-    );
-}
-
-#[test]
-fn loose_negotiation_rejects_negative_returned_length() {
-    let config = ClientConfig::default();
-    let requested = params_from_config(&config).unwrap();
-    let mut returned = requested.clone();
-    returned.length = -1;
-    assert_eq!(
-        rejection_reason(&requested, &returned, NegotiationPolicy::Loose),
-        "length must be non-negative"
-    );
-}
-
-#[test]
-fn strict_negotiation_rejects_negative_returned_length() {
-    let config = ClientConfig::default();
-    let requested = params_from_config(&config).unwrap();
-    let mut returned = requested.clone();
-    returned.length = -1;
-    assert_eq!(
-        rejection_reason(&requested, &returned, NegotiationPolicy::Strict),
-        "length must be non-negative"
-    );
-}
-
-#[test]
-fn loose_negotiation_rejects_runtime_invalid_returned_dscp() {
-    let config = ClientConfig {
-        dscp: 46,
-        ..ClientConfig::default()
-    };
-    let requested = params_from_config(&config).unwrap();
-    assert_eq!(
-        requested.dscp, 184,
-        "codepoint 46 must become raw wire byte 184"
-    );
-
-    for dscp in [-1, 256] {
-        let mut returned = requested.clone();
-        returned.dscp = dscp;
-        assert_eq!(
-            rejection_reason(&requested, &returned, NegotiationPolicy::Loose),
-            "dscp must be in range 0..=255"
-        );
-    }
-
-    // A raw returned value of 184 must be accepted even though it exceeds the
-    // 0..=63 codepoint range; it is the correctly negotiated wire value for
-    // codepoint 46 and is not subject to the codepoint bound at all.
-    let returned = requested.clone();
-    assert!(
-        assert_negotiates(&requested, &returned, NegotiationPolicy::Loose)
-            .restrictions
-            .is_empty()
-    );
-}
-
-#[test]
-fn loose_negotiation_records_dscp_disabled_by_server() {
-    let config = ClientConfig {
-        dscp: 46,
-        ..ClientConfig::default()
-    };
-    let requested = params_from_config(&config).unwrap();
-    let mut returned = requested.clone();
-    returned.dscp = 0;
-
-    let negotiated = assert_negotiates(&requested, &returned, NegotiationPolicy::Loose);
-
-    assert_eq!(
-        negotiated.restrictions,
-        vec![NegotiationRestriction::DscpChanged {
-            requested: 46,
-            negotiated: 0,
-        }]
-    );
-}
-
-#[test]
-fn strict_negotiation_rejects_dscp_disabled_by_server_as_specific_restriction() {
-    let config = ClientConfig {
-        dscp: 46,
-        ..ClientConfig::default()
-    };
-    let requested = params_from_config(&config).unwrap();
-    let mut returned = requested.clone();
-    returned.dscp = 0;
-
-    assert_eq!(
-        rejection_reason(&requested, &returned, NegotiationPolicy::Strict),
-        NegotiationRestriction::DscpChanged {
-            requested: 46,
-            negotiated: 0,
-        }
-        .message()
-    );
-}
-
-#[test]
-fn negotiation_rejects_unsupported_dscp_changes() {
-    let config = ClientConfig {
-        dscp: 46,
-        ..ClientConfig::default()
-    };
-    let requested = params_from_config(&config).unwrap();
-    let mut returned = requested.clone();
-    returned.dscp = 8;
-
-    assert_eq!(
-        rejection_reason(&requested, &returned, NegotiationPolicy::Loose),
-        "server returned unsupported DSCP change"
-    );
-    assert_eq!(
-        rejection_reason(&requested, &returned, NegotiationPolicy::Strict),
-        "server returned unsupported DSCP change"
-    );
-
-    let zero_config = ClientConfig::default();
-    let zero_requested = params_from_config(&zero_config).unwrap();
-    let mut returned = zero_requested.clone();
-    returned.dscp = 46;
-
-    assert_eq!(
-        rejection_reason(&zero_requested, &returned, NegotiationPolicy::Loose),
-        "server returned unsupported DSCP change"
-    );
-}

crates/irtt-client/src/client/tests/open.rs

@@ -1,522 +0,0 @@
-use super::*;
-
-#[test]
-fn successful_open_handshake() {
-    let config = default_test_config(SocketAddr::from(([127, 0, 0, 1], 1)));
-    let params = params_from_config(&config).unwrap();
-    let server = open_success_server(params.clone());
-    let mut client = Client::connect(default_test_config(server.addr)).unwrap();
-
-    let negotiated = assert_open_started(client.open().unwrap());
-    assert_eq!(negotiated.params, params);
-    assert!(client.schedule.is_some());
-    assert_eq!(client.applied_traffic_class, Some(0));
-    server.join();
-}
-
-#[test]
-fn successful_open_restores_configured_receive_timeout() {
-    let config = default_test_config(SocketAddr::from(([127, 0, 0, 1], 1)));
-    let params = params_from_config(&config).unwrap();
-    let server = open_success_server(params);
-    let mut config = default_test_config(server.addr);
-    config.socket_config.recv_timeout = Some(Duration::from_millis(75));
-    let mut client = Client::connect(config).unwrap();
-
-    assert_open_started(client.open().unwrap());
-
-    assert_eq!(
-        client.test_hooks.last_restored_read_timeout.get(),
-        Some(Duration::from_millis(75))
-    );
-    server.join();
-}
-
-#[test]
-fn open_fails_when_already_open() {
-    let config = default_test_config(SocketAddr::from(([127, 0, 0, 1], 1)));
-    let params = params_from_config(&config).unwrap();
-    let server = open_success_server(params);
-    let mut client = Client::connect(default_test_config(server.addr)).unwrap();
-    assert_open_started(client.open().unwrap());
-    assert!(matches!(client.open(), Err(ClientError::AlreadyOpen)));
-    server.join();
-}
-
-#[test]
-fn open_retries_after_first_timeout() {
-    let server = start_fake_server(|socket, tx| {
-        let (first, _) = recv_request(&socket, &tx);
-        let (_, peer) = recv_request(&socket, &tx);
-        let params = Params::decode(&first[4..]).unwrap();
-        let reply = open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, None);
-        assert_eq!(first[3] & FLAG_OPEN, FLAG_OPEN);
-        socket.send_to(&reply, peer).unwrap();
-    });
-    let config = ClientConfig {
-        open_timeouts: vec![Duration::from_millis(200), Duration::from_millis(500)],
-        ..default_test_config(server.addr)
-    };
-    let mut client = Client::connect(config).unwrap();
-    let outcome = client.open().unwrap();
-    assert_open_started(outcome);
-    assert_eq!(server.rx.iter().take(2).count(), 2);
-    server.join();
-}
-
-#[test]
-fn open_survives_interrupted_receive_within_same_attempt() {
-    let server = start_fake_server(|socket, tx| {
-        let (first, peer) = recv_request(&socket, &tx);
-        let params = Params::decode(&first[4..]).unwrap();
-        let reply = open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, None);
-        socket.send_to(&reply, peer).unwrap();
-    });
-    let config = ClientConfig {
-        open_timeouts: vec![Duration::from_millis(500)],
-        ..default_test_config(server.addr)
-    };
-    let mut client = Client::connect(config).unwrap();
-    // Several interrupted receive attempts before the real reply arrives
-    // must not be treated as a timeout, must not retransmit the open
-    // request, and must not advance to a next configured attempt.
-    client.test_hooks.inject_recv_interrupted.set(5);
-
-    let outcome = client.open().unwrap();
-    assert_open_started(outcome);
-    // Exactly one request reached the server: interruptions were absorbed
-    // inside the single configured attempt.
-    assert_eq!(server.rx.iter().take(1).count(), 1);
-    server.join();
-}
-
-#[test]
-fn open_interrupted_receive_does_not_extend_the_attempt_deadline() {
-    // A fake server that never replies: with a short attempt timeout, the
-    // real question is whether interruptions can push the effective wait
-    // past the configured deadline. They must not: the deadline stays
-    // absolute across any number of interruptions.
-    let server = start_fake_server(|socket, tx| {
-        let _ = recv_request(&socket, &tx);
-    });
-    let config = ClientConfig {
-        open_timeouts: vec![Duration::from_millis(200)],
-        ..default_test_config(server.addr)
-    };
-    let mut client = Client::connect(config).unwrap();
-    // Each interruption carries no timing information of its own, so the
-    // loop must keep re-checking the real deadline rather than treating an
-    // interruption as "more time available" or a reason to fail outright.
-    client.test_hooks.inject_recv_interrupted.set(20);
-
-    let started = Instant::now();
-    let result = client.open();
-    let elapsed = started.elapsed();
-
-    assert!(matches!(result, Err(ClientError::OpenTimeout)));
-    assert!(
-        elapsed < Duration::from_millis(800),
-        "interrupted receives must not extend the attempt deadline, took {elapsed:?}"
-    );
-    server.join();
-}
-
-#[test]
-fn open_timeout_after_all_timeouts() {
-    let server = timeout_server(Duration::from_millis(700));
-    let config = ClientConfig {
-        open_timeouts: vec![Duration::from_millis(200), Duration::from_millis(200)],
-        socket_config: crate::SocketConfig {
-            recv_timeout: Some(Duration::from_millis(50)),
-            ..Default::default()
-        },
-        ..default_test_config(server.addr)
-    };
-    let mut client = Client::connect(config).unwrap();
-    assert!(matches!(client.open(), Err(ClientError::OpenTimeout)));
-    assert_eq!(server.rx.iter().take(2).count(), 2);
-    assert_eq!(
-        client.test_hooks.last_restored_read_timeout.get(),
-        Some(Duration::from_millis(50))
-    );
-    server.join();
-}
-
-#[test]
-fn protocol_version_mismatch_fails() {
-    let mut config = default_test_config(SocketAddr::from(([127, 0, 0, 1], 1)));
-    config.negotiation_policy = NegotiationPolicy::Loose;
-    let mut params = params_from_config(&config).unwrap();
-    params.protocol_version = 2;
-    let server = open_success_server(params);
-    let mut client = Client::connect(default_test_config(server.addr)).unwrap();
-    assert!(matches!(
-        client.open(),
-        Err(ClientError::ProtocolVersionMismatch { received: 2, .. })
-    ));
-    assert_eq!(server.rx.iter().take(1).count(), 1);
-    assert!(client.runtime.prepare_open_request().is_ok());
-    server.join();
-}
-
-#[test]
-fn server_rejection_fails_in_normal_mode() {
-    let config = default_test_config(SocketAddr::from(([127, 0, 0, 1], 1)));
-    let params = params_from_config(&config).unwrap();
-    let server = start_fake_server(move |socket, tx| {
-        let (_, peer) = recv_request(&socket, &tx);
-        let reply = open_reply(FLAG_OPEN | FLAG_REPLY | flags::FLAG_CLOSE, 0, &params, None);
-        socket.send_to(&reply, peer).unwrap();
-    });
-    let mut client = Client::connect(default_test_config(server.addr)).unwrap();
-    assert!(matches!(client.open(), Err(ClientError::ServerRejected)));
-    assert_eq!(server.rx.iter().take(1).count(), 1);
-    assert!(client.runtime.prepare_open_request().is_ok());
-    server.join();
-}
-
-#[test]
-fn multiple_untrusted_datagrams_before_valid_reply_use_one_attempt() {
-    let params = default_params();
-    let server = start_fake_server(move |socket, tx| {
-        let (_, peer) = recv_request(&socket, &tx);
-        let valid = open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, None);
-        let mut wrong_type = valid.clone();
-        wrong_type[3] = FLAG_REPLY;
-        let mut reserved_flags = valid.clone();
-        reserved_flags[3] |= 0x10;
-        let mut bad_magic = valid.clone();
-        bad_magic[0] ^= 0xff;
-        let unexpected_hmac =
-            open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, Some(b"unexpected"));
-
-        for packet in [
-            vec![0_u8],
-            bad_magic,
-            wrong_type,
-            reserved_flags,
-            unexpected_hmac,
-            valid,
-        ] {
-            socket.send_to(&packet, peer).unwrap();
-        }
-    });
-    let mut client = Client::connect(default_test_config(server.addr)).unwrap();
-
-    assert_open_started(client.open().unwrap());
-    assert_eq!(server.rx.iter().take(1).count(), 1);
-    assert!(server.rx.try_recv().is_err());
-    assert!(client.schedule.is_some());
-    server.join();
-}
-
-#[test]
-fn ignored_datagrams_do_not_restart_the_attempt_deadline() {
-    let server = start_fake_server(move |socket, tx| {
-        let (_, peer) = recv_request(&socket, &tx);
-        thread::sleep(Duration::from_millis(150));
-        socket.send_to(&[0_u8], peer).unwrap();
-        thread::sleep(Duration::from_millis(150));
-        socket.send_to(&[0_u8], peer).unwrap();
-        let _ = recv_request(&socket, &tx);
-    });
-    let config = ClientConfig {
-        open_timeouts: vec![Duration::from_millis(250), Duration::from_millis(250)],
-        ..default_test_config(server.addr)
-    };
-    let mut client = Client::connect(config).unwrap();
-    let started = Instant::now();
-
-    assert!(matches!(client.open(), Err(ClientError::OpenTimeout)));
-    let requests: Vec<_> = server.rx.iter().take(2).collect();
-    assert_eq!(requests.len(), 2);
-    assert!(
-        started.elapsed() < Duration::from_millis(700),
-        "ignored datagrams restarted an attempt deadline"
-    );
-    server.join();
-}
-
-#[test]
-fn only_ignored_open_datagrams_eventually_time_out() {
-    let server = start_fake_server(move |socket, tx| {
-        for _ in 0..2 {
-            let (_, peer) = recv_request(&socket, &tx);
-            socket.send_to(&[0_u8], peer).unwrap();
-            socket.send_to(&MAGIC, peer).unwrap();
-        }
-        thread::sleep(Duration::from_millis(300));
-    });
-    let config = ClientConfig {
-        open_timeouts: vec![Duration::from_millis(200), Duration::from_millis(200)],
-        socket_config: crate::SocketConfig {
-            recv_timeout: Some(Duration::from_millis(50)),
-            ..Default::default()
-        },
-        ..default_test_config(server.addr)
-    };
-    let mut client = Client::connect(config).unwrap();
-
-    assert!(matches!(client.open(), Err(ClientError::OpenTimeout)));
-    assert_eq!(server.rx.iter().take(2).count(), 2);
-    assert!(server.rx.try_recv().is_err());
-    assert_eq!(
-        client.test_hooks.last_restored_read_timeout.get(),
-        Some(Duration::from_millis(50))
-    );
-    server.join();
-}
-
-#[test]
-fn trusted_zero_token_normal_reply_is_terminal() {
-    let params = default_params();
-    let server = start_fake_server(move |socket, tx| {
-        let (_, peer) = recv_request(&socket, &tx);
-        // encode_open_reply rejects a zero token without FLAG_CLOSE, so this
-        // deliberately non-compliant reply is built by encoding a normal
-        // reply with a placeholder token and then zeroing the token field.
-        let mut reply = open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, None);
-        reply[HMAC_OFFSET..HMAC_OFFSET + 8].copy_from_slice(&0_u64.to_le_bytes());
-        socket.send_to(&reply, peer).unwrap();
-    });
-    let mut client = Client::connect(default_test_config(server.addr)).unwrap();
-
-    assert!(matches!(
-        client.open(),
-        Err(ClientError::Protocol(irtt_proto::ProtoError::ZeroToken))
-    ));
-    assert_eq!(server.rx.iter().take(1).count(), 1);
-    assert!(client.runtime.prepare_open_request().is_ok());
-    assert!(client.schedule.is_none());
-    server.join();
-}
-
-#[test]
-fn opening_deadline_overflow_occurs_before_send() {
-    let server = timeout_server(Duration::from_millis(250));
-    let config = ClientConfig {
-        open_timeouts: vec![Duration::MAX],
-        ..default_test_config(server.addr)
-    };
-    let mut client = Client::connect(config).unwrap();
-
-    assert!(matches!(client.open(), Err(ClientError::DurationOverflow)));
-    assert!(server.rx.try_recv().is_err());
-    server.join();
-}
-
-#[test]
-fn schedule_duration_overflow_cannot_partially_open() {
-    let server = start_fake_server(|_socket, _tx| {});
-    let client = Client::connect(default_test_config(server.addr)).unwrap();
-    let reply = irtt_proto::OpenReply {
-        flags: FLAG_OPEN | FLAG_REPLY,
-        token: TOKEN,
-        params: params_from_config(client.runtime.config()).unwrap(),
-    };
-    let mut latest = Instant::now();
-    let mut step = Duration::MAX;
-    while !step.is_zero() {
-        if let Some(candidate) = latest.checked_add(step) {
-            latest = candidate;
-        }
-        step /= 2;
-    }
-    let opened_at = ClientTimestamp {
-        mono: latest,
-        wall: SystemTime::now(),
-    };
-    let machine = client
-        .runtime
-        .prepare_open_acceptance(reply, opened_at)
-        .unwrap();
-    let previous_recv_len = client.recv_buffer.len();
-
-    let failure = client.prepare_client_open(machine, opened_at).unwrap_err();
-
-    assert!(matches!(
-        failure.primary,
-        ClientError::NegotiationRejected { .. }
-    ));
-    assert!(failure.machine.cleanup_close_packet().is_some());
-    assert!(client.runtime.prepare_open_request().is_ok());
-    assert!(client.schedule.is_none());
-    assert_eq!(client.applied_traffic_class, None);
-    assert_eq!(client.recv_buffer.len(), previous_recv_len);
-    server.join();
-}
-
-#[test]
-fn post_token_negotiation_failure_sends_cleanup_close() {
-    let mut returned = default_params();
-    returned.interval_ns += 1;
-    let server = start_fake_server(move |socket, tx| {
-        let (_, peer) = recv_request(&socket, &tx);
-        socket
-            .send_to(
-                &open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &returned, None),
-                peer,
-            )
-            .unwrap();
-        let _ = recv_request(&socket, &tx);
-    });
-    let mut client = Client::connect(default_test_config(server.addr)).unwrap();
-
-    assert!(matches!(
-        client.open(),
-        Err(ClientError::NegotiationRejected { .. })
-    ));
-    let packets: Vec<_> = server.rx.iter().take(2).collect();
-    assert_eq!(packets[1][3], flags::FLAG_CLOSE);
-    assert_eq!(
-        u64::from_le_bytes(packets[1][4..12].try_into().unwrap()),
-        TOKEN
-    );
-    assert!(client.runtime.prepare_open_request().is_ok());
-    server.join();
-}
-
-#[test]
-fn cleanup_send_failure_does_not_replace_primary_open_error() {
-    let mut returned = default_params();
-    returned.interval_ns += 1;
-    let server = start_fake_server(move |socket, tx| {
-        let (_, peer) = recv_request(&socket, &tx);
-        socket
-            .send_to(
-                &open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &returned, None),
-                peer,
-            )
-            .unwrap();
-    });
-    let mut client = Client::connect(default_test_config(server.addr)).unwrap();
-    client.test_hooks.fail_cleanup_send.set(true);
-
-    assert!(matches!(
-        client.open(),
-        Err(ClientError::NegotiationRejected { .. })
-    ));
-    assert!(client.runtime.prepare_open_request().is_ok());
-    server.join();
-}
-
-#[test]
-fn receive_buffer_reservation_failure_precedes_dscp_application() {
-    let mut returned = default_params();
-    // Raw wire TOS/Traffic Class byte for DSCP codepoint 46 (EF), matching
-    // what the client below requests so negotiation succeeds unchanged.
-    returned.dscp = 184;
-    let server = start_fake_server(move |socket, tx| {
-        let (_, peer) = recv_request(&socket, &tx);
-        socket
-            .send_to(
-                &open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &returned, None),
-                peer,
-            )
-            .unwrap();
-        let _ = recv_request(&socket, &tx);
-    });
-    let mut config = default_test_config(server.addr);
-    config.dscp = 46;
-    let mut client = Client::connect(config).unwrap();
-    client
-        .test_hooks
-        .recv_buffer_len_override
-        .set(Some(usize::MAX));
-    client.test_hooks.fail_open_dscp.set(true);
-
-    assert!(matches!(
-        client.open(),
-        Err(ClientError::AllocationFailed {
-            operation: "negotiated receive buffer",
-            ..
-        })
-    ));
-    assert!(client.test_hooks.fail_open_dscp.get());
-    assert!(client.runtime.prepare_open_request().is_ok());
-    assert!(client.schedule.is_none());
-    assert_eq!(client.applied_traffic_class, None);
-    server.join();
-}
-
-#[test]
-fn dscp_application_failure_leaves_machine_connected() {
-    let params = default_params();
-    let server = start_fake_server(move |socket, tx| {
-        let (_, peer) = recv_request(&socket, &tx);
-        socket
-            .send_to(
-                &open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, None),
-                peer,
-            )
-            .unwrap();
-        let _ = recv_request(&socket, &tx);
-    });
-    let mut client = Client::connect(default_test_config(server.addr)).unwrap();
-    client.test_hooks.fail_open_dscp.set(true);
-
-    assert!(matches!(
-        client.open(),
-        Err(ClientError::SocketOption {
-            operation: "set negotiated DSCP",
-            ..
-        })
-    ));
-    assert!(client.test_hooks.prepared_active_session_before_dscp.get());
-    assert!(client.runtime.prepare_open_request().is_ok());
-    assert!(client.schedule.is_none());
-    assert_eq!(client.applied_traffic_class, None);
-    server.join();
-}
-
-#[test]
-fn read_timeout_restoration_failure_leaves_machine_connected() {
-    let params = default_params();
-    let server = start_fake_server(move |socket, tx| {
-        let (_, peer) = recv_request(&socket, &tx);
-        socket
-            .send_to(
-                &open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, None),
-                peer,
-            )
-            .unwrap();
-        let _ = recv_request(&socket, &tx);
-    });
-    let mut client = Client::connect(default_test_config(server.addr)).unwrap();
-    client.test_hooks.fail_open_timeout_restore.set(true);
-
-    assert!(matches!(
-        client.open(),
-        Err(ClientError::ReadTimeoutRestore { .. })
-    ));
-    assert!(client.runtime.prepare_open_request().is_ok());
-    assert!(client.schedule.is_none());
-    assert_eq!(client.applied_traffic_class, None);
-    server.join();
-}
-
-#[test]
-fn dscp_rollback_failure_keeps_timeout_restoration_primary() {
-    let params = default_params();
-    let server = start_fake_server(move |socket, tx| {
-        let (_, peer) = recv_request(&socket, &tx);
-        socket
-            .send_to(
-                &open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, None),
-                peer,
-            )
-            .unwrap();
-        let _ = recv_request(&socket, &tx);
-    });
-    let mut client = Client::connect(default_test_config(server.addr)).unwrap();
-    client.test_hooks.fail_open_timeout_restore.set(true);
-    client.test_hooks.fail_dscp_restore.set(true);
-
-    let error = client.open().unwrap_err();
-
-    assert!(matches!(error, ClientError::ReadTimeoutRestore { .. }));
-    assert!(client.runtime.prepare_open_request().is_ok());
-    assert!(client.schedule.is_none());
-    assert_eq!(client.applied_traffic_class, None);
-    server.join();
-}

crates/irtt-client/src/client/tests/probes_replies/interrupted_receive.rs

@@ -1,80 +0,0 @@
-use super::*;
-
-/// An interrupted receive (`io::ErrorKind::Interrupted`, e.g. `EINTR`) must be
-/// invisible to the caller: retried transparently, with the eventual reply
-/// classified exactly as if no interruption had occurred.
-#[test]
-fn interrupted_receive_is_retried_and_the_reply_is_still_classified() {
-    let params = default_params();
-    let server = start_fake_server(move |socket, tx| {
-        let (_, peer) = recv_request(&socket, &tx);
-        let reply = open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, None);
-        socket.send_to(&reply, peer).unwrap();
-
-        let mut buf = [0_u8; 2048];
-        let (size, _) = socket.recv_from(&mut buf).unwrap();
-        let seq = u32::from_le_bytes(buf[12..16].try_into().unwrap());
-        let _ = size;
-        let ts = TimestampFields::default();
-        let reply_packet = echo_reply_packet(TOKEN, seq, &params, &ts, None);
-        socket.send_to(&reply_packet, peer).unwrap();
-    });
-    let config = ClientConfig {
-        socket_config: crate::SocketConfig {
-            recv_timeout: Some(Duration::from_secs(2)),
-            ..Default::default()
-        },
-        ..default_test_config(server.addr)
-    };
-    let mut client = Client::connect(config).unwrap();
-    assert_open_started(client.open().unwrap());
-
-    client.send_probe().unwrap();
-    thread::sleep(Duration::from_millis(50));
-
-    client.test_hooks.inject_recv_interrupted.set(10);
-    let events = client.recv_once().unwrap();
-
-    assert_eq!(events.len(), 1);
-    assert!(
-        matches!(&events[0], ClientEvent::EchoReply { seq: 0, .. }),
-        "expected a normal EchoReply despite interrupted receive attempts, got {:?}",
-        events[0]
-    );
-
-    client.close().unwrap();
-    server.join();
-}
-
-/// One logical receive keeps one timeout budget: repeated interruptions must
-/// not extend a `recv_once` call past its configured receive timeout.
-#[test]
-fn interrupted_receive_does_not_extend_the_configured_timeout() {
-    let params = default_params();
-    let server = silent_open_server(params);
-    let config = ClientConfig {
-        socket_config: crate::SocketConfig {
-            recv_timeout: Some(Duration::from_millis(100)),
-            ..Default::default()
-        },
-        ..default_test_config(server.addr)
-    };
-    let mut client = Client::connect(config).unwrap();
-    assert_open_started(client.open().unwrap());
-
-    // No reply is ever coming; only interrupted attempts occur before the
-    // real socket takes over and legitimately times out.
-    client.test_hooks.inject_recv_interrupted.set(20);
-    let started = Instant::now();
-    let events = client.recv_once().unwrap();
-    let elapsed = started.elapsed();
-
-    assert!(events.is_empty());
-    assert!(
-        elapsed < Duration::from_millis(500),
-        "interrupted receives must not extend the configured receive timeout, took {elapsed:?}"
-    );
-
-    client.close().unwrap();
-    server.join();
-}

crates/irtt-client/src/client/tests/probes_replies/probe_schedule.rs

@@ -1,487 +0,0 @@
-use super::*;
-
-fn probe_timestamps(permission_at: Instant, sent_at: ClientTimestamp) -> ProbeSendTimestamps {
-    ProbeSendTimestamps {
-        permission_at,
-        send_anchor: sent_at,
-        sent_at,
-        send_call_start: sent_at.mono,
-        send_finished_at: sent_at.mono,
-    }
-}
-
-#[test]
-fn send_probe_fails_before_open() {
-    let server = start_fake_server(|_socket, _tx| {});
-    let mut client = Client::connect(default_test_config(server.addr)).unwrap();
-    assert!(matches!(client.send_probe(), Err(ClientError::NotOpen)));
-    server.join();
-}
-
-#[test]
-fn send_probe_sends_valid_echo_request() {
-    let params = default_params();
-    let server = silent_open_server(params.clone());
-    let config = ClientConfig {
-        socket_config: crate::SocketConfig {
-            recv_timeout: Some(Duration::from_millis(200)),
-            ..Default::default()
-        },
-        ..default_test_config(server.addr)
-    };
-    let mut client = Client::connect(config).unwrap();
-    assert!(client.next_send_deadline().is_none());
-    assert_open_started(client.open().unwrap());
-    let events = client.send_probe().unwrap();
-    assert_eq!(events.len(), 1);
-    match &events[0] {
-        ClientEvent::EchoSent {
-            seq, remote, bytes, ..
-        } => {
-            assert_eq!(*seq, 0);
-            assert_eq!(*remote, server.addr);
-            assert_eq!(*bytes, echo_packet_len(false, &params));
-        }
-        other => panic!("expected EchoSent, got {other:?}"),
-    }
-    thread::sleep(Duration::from_millis(30));
-    let packets: Vec<_> = server.rx.try_iter().collect();
-    let echo_reqs: Vec<_> = packets
-        .iter()
-        .filter(|p| p.len() >= 4 && p[3] & FLAG_OPEN == 0)
-        .collect();
-    let echo_req = echo_reqs.first().unwrap();
-    assert_eq!(&echo_req[..3], &MAGIC);
-    assert_eq!(echo_req[3], 0x00);
-    let req_token = u64::from_le_bytes(echo_req[4..12].try_into().unwrap());
-    assert_eq!(req_token, TOKEN);
-    let seq = u32::from_le_bytes(echo_req[12..16].try_into().unwrap());
-    assert_eq!(seq, 0);
-    client.close().unwrap();
-    server.join();
-}
-
-#[test]
-fn blocking_short_probe_commits_before_presentation_length_error() {
-    let params = default_params();
-    let server = silent_open_server(params.clone());
-    let mut client = Client::connect(default_test_config(server.addr)).unwrap();
-    assert_open_started(client.open().unwrap());
-
-    let expected = echo_packet_len(false, &params);
-    let initial_deadline = client.next_send_deadline().unwrap();
-    client.probe_reported_len = Some(expected - 1);
-
-    assert!(matches!(
-        client.send_probe(),
-        Err(ClientError::DatagramLengthMismatch {
-            expected: error_expected,
-            actual,
-        }) if error_expected == expected && actual + 1 == expected
-    ));
-    assert_eq!(client.runtime.packets_sent(), 1);
-    assert_eq!(
-        client.next_send_deadline(),
-        Some(initial_deadline + client.runtime.config().interval)
-    );
-
-    client.close().unwrap();
-    server.join();
-}
-
-#[test]
-fn blocking_failed_probe_send_preserves_machine_and_schedule() {
-    let params = default_params();
-    let server = silent_open_server(params);
-    let mut client = Client::connect(default_test_config(server.addr)).unwrap();
-    assert_open_started(client.open().unwrap());
-
-    let initial_deadline = client.next_send_deadline().unwrap();
-    client.probe_send_error = true;
-
-    assert!(matches!(client.send_probe(), Err(ClientError::Socket(_))));
-    assert_eq!(client.runtime.packets_sent(), 0);
-    assert_eq!(client.next_send_deadline(), Some(initial_deadline));
-
-    assert!(matches!(
-        client.send_probe().unwrap().as_slice(),
-        [ClientEvent::EchoSent { seq: 0, .. }]
-    ));
-
-    client.close().unwrap();
-    server.join();
-}
-
-#[test]
-fn blocking_timeout_finalization_overflow_does_not_send_or_commit() {
-    let params = default_params();
-    let server = silent_open_server(params);
-    let config = ClientConfig {
-        probe_timeout: Duration::MAX,
-        ..default_test_config(server.addr)
-    };
-    let mut client = Client::connect(config).unwrap();
-    assert_open_started(client.open().unwrap());
-
-    let initial_deadline = client.next_send_deadline().unwrap();
-    let sent_at = ClientTimestamp {
-        mono: Instant::now(),
-        wall: SystemTime::now(),
-    };
-
-    assert!(matches!(
-        client.send_probe_at(probe_timestamps(initial_deadline, sent_at)),
-        Err(ClientError::DurationOverflow)
-    ));
-    assert_eq!(client.runtime.packets_sent(), 0);
-    assert_eq!(client.next_send_deadline(), Some(initial_deadline));
-    thread::sleep(Duration::from_millis(30));
-    assert!(server
-        .rx
-        .try_iter()
-        .all(|packet| packet.len() >= 4 && packet[3] & FLAG_OPEN != 0));
-
-    client.close().unwrap();
-    server.join();
-}
-
-#[test]
-fn blocking_probe_separates_permission_committed_send_and_send_call_timing() {
-    let duration = Duration::from_secs(1);
-    let interval = Duration::from_millis(100);
-    let params = Params {
-        duration_ns: 1_000_000_000,
-        interval_ns: 100_000_000,
-        ..default_params()
-    };
-    let server = silent_open_server(params.clone());
-    let config = ClientConfig {
-        duration: Some(duration),
-        interval,
-        ..default_test_config(server.addr)
-    };
-    let mut client = Client::connect(config).unwrap();
-    assert_open_started(client.open().unwrap());
-
-    let opened_mono = Instant::now()
-        .checked_sub(Duration::from_secs(2))
-        .expect("test host monotonic clock has at least two seconds of history");
-    client.schedule = Some(
-        ProbeSchedule::new(
-            opened_mono,
-            &NegotiatedParams {
-                params,
-                restrictions: Vec::new(),
-            },
-        )
-        .unwrap(),
-    );
-    let permission_at = opened_mono + Duration::from_millis(500);
-    // Distinct pre-send anchor and post-send `sent_at`: the anchor drives
-    // the operational timeout deadline, while `sent_at` (captured after the
-    // send call) is the public measurement/timer_error endpoint. They are
-    // deliberately decoupled by this PR.
-    let send_anchor = ClientTimestamp {
-        wall: SystemTime::now(),
-        mono: opened_mono + Duration::from_millis(525),
-    };
-    let sent_at = ClientTimestamp {
-        wall: SystemTime::now(),
-        mono: opened_mono + Duration::from_millis(534),
-    };
-    let timestamps = ProbeSendTimestamps {
-        permission_at,
-        send_anchor,
-        sent_at,
-        send_call_start: opened_mono + Duration::from_millis(526),
-        send_finished_at: opened_mono + Duration::from_millis(533),
-    };
-
-    let events = client.send_probe_at(timestamps).unwrap();
-
-    assert!(matches!(
-        events.as_slice(),
-        [ClientEvent::EchoSent {
-            scheduled_at,
-            sent_at: event_sent_at,
-            send_call,
-            timer_error,
-            ..
-        }] if *scheduled_at == opened_mono
-            && *event_sent_at == sent_at
-            && *send_call == Duration::from_millis(7)
-            && *timer_error == Duration::from_millis(534)
-    ));
-    assert_eq!(client.next_send_deadline(), Some(opened_mono + interval));
-    assert_eq!(client.runtime.packets_sent(), 1);
-    // The timeout deadline is anchored to the pre-send `send_anchor`, not
-    // to the post-send `sent_at` captured 9ms later.
-    let timeout_at = send_anchor.mono + client.probe_timeout();
-    assert_ne!(timeout_at, sent_at.mono + client.probe_timeout());
-    assert!(client
-        .poll_timeouts_at(timeout_at - Duration::from_nanos(1))
-        .unwrap()
-        .is_empty());
-    assert!(matches!(
-        client.poll_timeouts_at(timeout_at).unwrap().as_slice(),
-        [ClientEvent::EchoLoss {
-            sent_at: loss_sent_at,
-            ..
-        }] if *loss_sent_at == sent_at
-    ));
-
-    client.close().unwrap();
-    server.join();
-}
-
-#[test]
-fn blocking_send_call_excludes_wrapped_history_cleanup() {
-    let params = default_params();
-    let server = silent_open_server(params);
-    let mut client = Client::connect(default_test_config(server.addr)).unwrap();
-    assert_open_started(client.open().unwrap());
-
-    let scheduled_at = client.next_send_deadline().unwrap();
-    let sent_at = ClientTimestamp {
-        wall: SystemTime::now(),
-        mono: scheduled_at + Duration::from_millis(5),
-    };
-    client.runtime.seed_wrapped_probe_history_for_test(sent_at);
-    let timestamps = ProbeSendTimestamps {
-        permission_at: scheduled_at,
-        send_anchor: sent_at,
-        sent_at,
-        send_call_start: scheduled_at + Duration::from_millis(6),
-        send_finished_at: scheduled_at + Duration::from_millis(13),
-    };
-
-    let events = client.send_probe_at(timestamps).unwrap();
-
-    assert!(matches!(
-        events.as_slice(),
-        [ClientEvent::EchoSent {
-            seq: 0,
-            send_call,
-            ..
-        }] if *send_call == Duration::from_millis(7)
-    ));
-    assert!(!client.runtime.has_timed_out_metadata());
-
-    client.close().unwrap();
-    server.join();
-}
-
-#[test]
-fn send_probe_respects_finite_duration_exclusive_end() {
-    let params = Params {
-        protocol_version: 1,
-        duration_ns: 1_000_000_000,
-        interval_ns: 500_000_000,
-        received_stats: ReceivedStats::Both,
-        stamp_at: StampAt::Both,
-        clock: Clock::Both,
-        ..Params::default()
-    };
-    let server = silent_open_server(params.clone());
-    let config = ClientConfig {
-        duration: Some(Duration::from_secs(1)),
-        interval: Duration::from_millis(500),
-        socket_config: crate::SocketConfig {
-            recv_timeout: Some(Duration::from_millis(200)),
-            ..Default::default()
-        },
-        ..default_test_config(server.addr)
-    };
-    let mut client = Client::connect(config).unwrap();
-    assert_open_started(client.open().unwrap());
-
-    let start = client.next_send_deadline().unwrap();
-    let interval = Duration::from_millis(500);
-
-    let now0 = ClientTimestamp {
-        mono: start,
-        wall: SystemTime::now(),
-    };
-    assert!(client
-        .send_probe_at(probe_timestamps(now0.mono, now0))
-        .is_ok());
-
-    let now1 = ClientTimestamp {
-        mono: start + interval,
-        wall: SystemTime::now(),
-    };
-    assert!(client
-        .send_probe_at(probe_timestamps(now1.mono, now1))
-        .is_ok());
-
-    let now2 = ClientTimestamp {
-        mono: start + Duration::from_secs(1),
-        wall: SystemTime::now(),
-    };
-    let events = client
-        .send_probe_at(probe_timestamps(now2.mono, now2))
-        .unwrap();
-    assert!(events.is_empty());
-    assert!(client.next_send_deadline().is_none());
-
-    client.close().unwrap();
-    server.join();
-}
-
-#[test]
-fn managed_probe_skips_missed_schedule_slots() {
-    let interval = Duration::from_millis(10);
-    let params = Params {
-        protocol_version: 1,
-        duration_ns: 0,
-        interval_ns: 10_000_000,
-        received_stats: ReceivedStats::Both,
-        stamp_at: StampAt::Both,
-        clock: Clock::Both,
-        ..Params::default()
-    };
-    let server = echo_server(params);
-    let config = ClientConfig {
-        duration: None,
-        interval,
-        ..default_test_config(server.addr)
-    };
-    let mut client = Client::connect(config).unwrap();
-    assert_open_started(client.open().unwrap());
-
-    let first_deadline = client.next_send_deadline().unwrap();
-    let permission_at = first_deadline + Duration::from_millis(45);
-    let delayed_send = ClientTimestamp {
-        mono: first_deadline + Duration::from_millis(48),
-        wall: SystemTime::now(),
-    };
-    let timestamps = ProbeSendTimestamps {
-        permission_at,
-        send_anchor: delayed_send,
-        sent_at: delayed_send,
-        send_call_start: first_deadline + Duration::from_millis(49),
-        send_finished_at: first_deadline + Duration::from_millis(55),
-    };
-    let events = client
-        .send_managed_probe_at(first_deadline, timestamps)
-        .unwrap();
-
-    assert_eq!(events.len(), 1);
-    assert!(matches!(
-        events[0],
-        ClientEvent::EchoSent {
-            seq: 0,
-            scheduled_at,
-            sent_at,
-            send_call,
-            timer_error,
-            ..
-        } if scheduled_at == first_deadline + Duration::from_millis(40)
-            && sent_at == delayed_send
-            && send_call == Duration::from_millis(6)
-            && timer_error == Duration::from_millis(8)
-    ));
-    assert_eq!(
-        client.next_send_deadline(),
-        Some(first_deadline + Duration::from_millis(50))
-    );
-
-    client.close().unwrap();
-    server.join();
-}
-
-#[test]
-fn managed_probe_skip_preserves_finite_run_end() {
-    let interval = Duration::from_millis(10);
-    let duration = Duration::from_millis(50);
-    let params = Params {
-        protocol_version: 1,
-        duration_ns: 50_000_000,
-        interval_ns: 10_000_000,
-        received_stats: ReceivedStats::Both,
-        stamp_at: StampAt::Both,
-        clock: Clock::Both,
-        ..Params::default()
-    };
-    let server = echo_server(params);
-    let config = ClientConfig {
-        duration: Some(duration),
-        interval,
-        ..default_test_config(server.addr)
-    };
-    let mut client = Client::connect(config).unwrap();
-    assert_open_started(client.open().unwrap());
-
-    let first_deadline = client.next_send_deadline().unwrap();
-    let delayed_send = ClientTimestamp {
-        mono: first_deadline + Duration::from_millis(45),
-        wall: SystemTime::now(),
-    };
-    let first = client
-        .send_managed_probe_at(
-            first_deadline,
-            probe_timestamps(delayed_send.mono, delayed_send),
-        )
-        .unwrap();
-    let second_sent_at = ClientTimestamp {
-        mono: first_deadline + Duration::from_millis(46),
-        wall: SystemTime::now(),
-    };
-    let second = client
-        .send_managed_probe_at(
-            first_deadline + duration,
-            probe_timestamps(second_sent_at.mono, second_sent_at),
-        )
-        .unwrap();
-
-    assert_eq!(first.len(), 1);
-    assert!(second.is_empty());
-    assert!(client.next_send_deadline().is_none());
-
-    client.close().unwrap();
-    server.join();
-}
-
-#[test]
-fn receive_wait_is_bounded_by_next_ten_millisecond_deadline() {
-    let now = Instant::now();
-    let deadline = now + Duration::from_millis(10);
-
-    assert_eq!(
-        bounded_receive_timeout(
-            Some(deadline),
-            Some(Duration::from_millis(20)),
-            Duration::from_millis(20),
-            now,
-        ),
-        Some(Duration::from_millis(10))
-    );
-    assert_eq!(
-        bounded_receive_timeout(
-            Some(now),
-            Some(Duration::from_millis(20)),
-            Duration::from_millis(20),
-            now,
-        ),
-        None
-    );
-}
-
-#[test]
-fn connect_rejects_invalid_probe_limits() {
-    for config in [
-        ClientConfig {
-            max_pending_probes: 0,
-            ..ClientConfig::default()
-        },
-        ClientConfig {
-            probe_timeout: Duration::ZERO,
-            ..ClientConfig::default()
-        },
-    ] {
-        assert!(matches!(
-            Client::connect(config),
-            Err(ClientError::InvalidConfig { .. })
-        ));
-    }
-}

crates/irtt-client/src/client/tests/probes_replies/timing_math.rs

@@ -1,192 +0,0 @@
-use super::*;
-use crate::metadata::ReceiveMeta;
-
-#[test]
-fn server_processing_greater_than_raw_does_not_underflow() {
-    let base = Instant::now();
-    let rtt = compute_rtt(
-        &ClientTimestamp {
-            mono: base,
-            wall: SystemTime::now(),
-        },
-        &ClientTimestamp {
-            mono: base + Duration::from_nanos(1),
-            wall: SystemTime::now(),
-        },
-        &TimestampFields {
-            recv_mono: Some(0),
-            send_mono: Some(1_000_000_000),
-            ..Default::default()
-        },
-    );
-    assert_eq!(rtt.adjusted, Some(SignedDuration::from_nanos(-999_999_999)));
-    assert_eq!(rtt.effective, SignedDuration::from_nanos(-999_999_999));
-}
-
-#[test]
-fn effective_rtt_uses_raw_when_adjusted_rtt_is_unavailable() {
-    let base = Instant::now();
-    let rtt = compute_rtt(
-        &ClientTimestamp {
-            mono: base,
-            wall: SystemTime::now(),
-        },
-        &ClientTimestamp {
-            mono: base + Duration::from_nanos(42),
-            wall: SystemTime::now(),
-        },
-        &TimestampFields::default(),
-    );
-
-    assert_eq!(rtt.adjusted, None);
-    assert_eq!(rtt.effective, SignedDuration::from_duration(rtt.raw));
-}
-
-#[test]
-fn unix_epoch_ns_i64_rejects_out_of_range_wall_time() {
-    let i64_max_ns = u64::try_from(i64::MAX).unwrap();
-    let max = SystemTime::UNIX_EPOCH + Duration::from_nanos(i64_max_ns);
-    let overflow = max + Duration::from_nanos(1);
-
-    assert_eq!(unix_epoch_ns_i64(max), Some(i64::MAX));
-    assert_eq!(unix_epoch_ns_i64(overflow), None);
-}
-
-#[test]
-fn compute_one_way_omits_samples_when_client_wall_time_overflows_i64() {
-    let i64_max_ns = u64::try_from(i64::MAX).unwrap();
-    let overflow_wall =
-        SystemTime::UNIX_EPOCH + Duration::from_nanos(i64_max_ns) + Duration::from_nanos(1);
-    let sent_at = ClientTimestamp {
-        mono: Instant::now(),
-        wall: overflow_wall,
-    };
-    let received_at = ClientTimestamp {
-        mono: sent_at.mono + Duration::from_millis(40),
-        wall: overflow_wall + Duration::from_millis(40),
-    };
-    let ts = TimestampFields {
-        recv_wall: Some(i64::MAX),
-        send_wall: Some(i64::MAX),
-        ..Default::default()
-    };
-
-    assert_eq!(
-        compute_one_way(
-            &sent_at,
-            sent_at.wall,
-            &received_at,
-            None,
-            &ReceiveMeta::default(),
-            &ts
-        ),
-        None
-    );
-}
-
-#[test]
-fn compute_one_way_returns_available_direction_samples() {
-    let sent_at = ClientTimestamp {
-        mono: Instant::now(),
-        wall: SystemTime::UNIX_EPOCH + Duration::from_secs(10),
-    };
-    let received_at = ClientTimestamp {
-        mono: sent_at.mono + Duration::from_millis(40),
-        wall: SystemTime::UNIX_EPOCH + Duration::from_secs(10) + Duration::from_millis(40),
-    };
-    let ts = TimestampFields {
-        recv_wall: Some(10_000_000_000 + 15_000_000),
-        send_wall: Some(10_000_000_000 + 25_000_000),
-        ..Default::default()
-    };
-
-    let sample = compute_one_way(
-        &sent_at,
-        sent_at.wall,
-        &received_at,
-        None,
-        &ReceiveMeta::default(),
-        &ts,
-    )
-    .unwrap();
-    assert_eq!(
-        sample.client_to_server,
-        Some(SignedDuration::from_nanos(15_000_000))
-    );
-    assert_eq!(
-        sample.server_to_client,
-        Some(SignedDuration::from_nanos(15_000_000))
-    );
-}
-
-#[test]
-fn compute_one_way_preserves_negative_client_to_server_delay() {
-    let sent_at = ClientTimestamp {
-        mono: Instant::now(),
-        wall: SystemTime::UNIX_EPOCH + Duration::from_secs(10),
-    };
-    let received_at = ClientTimestamp {
-        mono: sent_at.mono + Duration::from_millis(40),
-        wall: SystemTime::UNIX_EPOCH + Duration::from_secs(10) + Duration::from_millis(40),
-    };
-    let ts = TimestampFields {
-        recv_wall: Some(10_000_000_000 - 5_000_000),
-        send_wall: Some(10_000_000_000 + 25_000_000),
-        ..Default::default()
-    };
-
-    let sample = compute_one_way(
-        &sent_at,
-        sent_at.wall,
-        &received_at,
-        None,
-        &ReceiveMeta::default(),
-        &ts,
-    )
-    .unwrap();
-
-    assert_eq!(
-        sample.client_to_server,
-        Some(SignedDuration::from_nanos(-5_000_000))
-    );
-    assert_eq!(
-        sample.server_to_client,
-        Some(SignedDuration::from_nanos(15_000_000))
-    );
-}
-
-#[test]
-fn compute_one_way_preserves_negative_server_to_client_delay() {
-    let sent_at = ClientTimestamp {
-        mono: Instant::now(),
-        wall: SystemTime::UNIX_EPOCH + Duration::from_secs(10),
-    };
-    let received_at = ClientTimestamp {
-        mono: sent_at.mono + Duration::from_millis(40),
-        wall: SystemTime::UNIX_EPOCH + Duration::from_secs(10) + Duration::from_millis(40),
-    };
-    let ts = TimestampFields {
-        recv_wall: Some(10_000_000_000 + 15_000_000),
-        send_wall: Some(10_000_000_000 + 45_000_000),
-        ..Default::default()
-    };
-
-    let sample = compute_one_way(
-        &sent_at,
-        sent_at.wall,
-        &received_at,
-        None,
-        &ReceiveMeta::default(),
-        &ts,
-    )
-    .unwrap();
-
-    assert_eq!(
-        sample.client_to_server,
-        Some(SignedDuration::from_nanos(15_000_000))
-    );
-    assert_eq!(
-        sample.server_to_client,
-        Some(SignedDuration::from_nanos(-5_000_000))
-    );
-}

crates/irtt-client/src/client/tests/sequence.rs

@@ -1,27 +0,0 @@
-use super::*;
-
-#[test]
-fn sequence_ordering_handles_normal_and_wrapped_values() {
-    assert!(sequence_is_after(11, 10));
-    assert!(sequence_is_before(9, 10));
-    assert!(!sequence_is_after(10, 10));
-    assert!(!sequence_is_before(10, 10));
-
-    assert!(sequence_is_after(0, u32::MAX - 1));
-    assert!(!sequence_is_before(0, u32::MAX - 1));
-    assert!(sequence_is_after(1, u32::MAX));
-    assert!(!sequence_is_before(1, u32::MAX));
-
-    assert!(sequence_is_before(u32::MAX, 1));
-    assert!(!sequence_is_after(u32::MAX, 1));
-}
-
-#[test]
-fn highest_received_seq_updates_across_wrap() {
-    let mut highest = Some(u32::MAX);
-
-    update_highest_received(&mut highest, 0);
-    assert_eq!(highest, Some(0));
-    update_highest_received(&mut highest, u32::MAX);
-    assert_eq!(highest, Some(0));
-}

crates/irtt-client/src/client/tests/ttl.rs

@@ -1,49 +0,0 @@
-use crate::socket_options::socket_ttl;
-
-use super::*;
-
-#[test]
-fn connect_accepts_valid_ttl_config_values() {
-    for ttl in [None, Some(1), Some(255)] {
-        let mut config = default_test_config(SocketAddr::from(([127, 0, 0, 1], 9)));
-        config.socket_config.ttl = ttl;
-        Client::connect(config).unwrap();
-    }
-}
-
-#[test]
-fn connect_applies_configured_ipv4_ttl_before_open_and_close_preserves_it() {
-    let params = Params {
-        protocol_version: PROTOCOL_VERSION,
-        duration_ns: 3_000_000_000,
-        interval_ns: 1_000_000_000,
-        received_stats: ReceivedStats::Both,
-        stamp_at: StampAt::Both,
-        clock: Clock::Both,
-        ..Params::default()
-    };
-    let server = open_success_server(params.clone());
-    let mut config = default_test_config(server.addr);
-    config.socket_config.ttl = Some(64);
-    let mut client = Client::connect(config).unwrap();
-
-    assert_eq!(socket_ttl(&client.socket, client.remote).unwrap(), 64);
-
-    client.open().unwrap();
-    server.join();
-
-    client.close().unwrap();
-    assert_eq!(socket_ttl(&client.socket, client.remote).unwrap(), 64);
-}
-
-#[test]
-fn connect_rejects_invalid_ttl_values() {
-    for ttl in [0, 256] {
-        let mut config = default_test_config(SocketAddr::from(([127, 0, 0, 1], 9)));
-        config.socket_config.ttl = Some(ttl);
-        assert!(matches!(
-            Client::connect(config),
-            Err(ClientError::InvalidConfig { .. })
-        ));
-    }
-}

crates/irtt-client/src/config.rs

@@ -46,6 +46,31 @@ pub(crate) const DEFAULT_MAX_PENDING: usize = 4096;
 /// request and the local client behavior used to drive the UDP socket. Values
 /// that are negotiated by the server are available after opening the session
 /// through [`NegotiatedParams`](crate::NegotiatedParams).
+///
+/// # Example
+///
+/// Configure a finite run with larger probes and accept documented server
+/// restrictions. Use `duration: None` for continuous mode, or
+/// [`RunMode::NoTest`] for negotiation without probes.
+///
+/// ```
+/// use std::time::Duration;
+///
+/// use irtt_client::{ClientConfig, NegotiationPolicy};
+///
+/// let config = ClientConfig {
+///     server_addr: "example.net:2112".into(),
+///     duration: Some(Duration::from_secs(10)),
+///     interval: Duration::from_millis(250),
+///     length: 1200,
+///     negotiation_policy: NegotiationPolicy::Loose,
+///     ..ClientConfig::default()
+/// };
+///
+/// assert_eq!(config.duration, Some(Duration::from_secs(10)));
+/// assert_eq!(config.interval, Duration::from_millis(250));
+/// assert_eq!(config.length, 1200);
+/// ```
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct ClientConfig {
     /// Remote server name or address.
@@ -60,12 +85,18 @@ pub struct ClientConfig {
     /// `None` requests continuous mode and is encoded on the wire as a zero
     /// duration. Use [`RunMode::NoTest`] when the caller wants negotiation only
     /// without sending probes.
+    ///
+    /// The managed driver stops sending after the negotiated duration.
+    /// Low-level adapters leave run duration to the caller.
     pub duration: Option<Duration>,
     /// Requested spacing between probe sends.
     ///
     /// The interval is encoded as nanoseconds in the open request and must be
     /// greater than zero. The server may return a different interval depending
     /// on the negotiated policy and server restrictions.
+    ///
+    /// The managed driver uses the negotiated interval for cadence.
+    /// Low-level adapters send whenever called.
     pub interval: Duration,
     /// Requested echo packet payload length, in bytes.
     ///
@@ -176,6 +207,29 @@ impl Default for ClientConfig {
 /// These settings affect how the client binds, resolves, and receives from the
 /// socket. They do not change the IRTT protocol parameters negotiated with the
 /// server.
+///
+/// # Example
+///
+/// Bind to a chosen local endpoint and set the outgoing IPv4 TTL:
+///
+/// ```
+/// use std::net::{Ipv4Addr, SocketAddr};
+///
+/// use irtt_client::{ClientConfig, SocketConfig};
+///
+/// let config = ClientConfig {
+///     socket_config: SocketConfig {
+///         bind_addr: Some(SocketAddr::from((Ipv4Addr::UNSPECIFIED, 0))),
+///         ttl: Some(32),
+///         ipv4_only: true,
+///         ..SocketConfig::default()
+///     },
+///     ..ClientConfig::default()
+/// };
+///
+/// assert_eq!(config.socket_config.ttl, Some(32));
+/// assert!(config.socket_config.ipv4_only);
+/// ```
 #[derive(Debug, Clone, PartialEq, Eq, Default)]
 pub struct SocketConfig {
     /// Local address to bind before connecting the UDP socket.
@@ -183,6 +237,15 @@ pub struct SocketConfig {
     /// `None` binds to an unspecified address with an ephemeral port matching
     /// the selected remote address family.
     pub bind_addr: Option<SocketAddr>,
+    /// Network interface to bind this socket to (`SO_BINDTODEVICE`).
+    #[cfg(any(target_os = "android", target_os = "fuchsia", target_os = "linux"))]
+    pub bind_to_device: Option<String>,
+    /// Firewall mark applied to outgoing packets (`SO_MARK`).
+    #[cfg(any(target_os = "android", target_os = "fuchsia", target_os = "linux"))]
+    pub mark: Option<u32>,
+    /// FreeBSD FIB used for routing this socket (`SO_SETFIB`).
+    #[cfg(target_os = "freebsd")]
+    pub fib: Option<u32>,
     /// Optional IPv4 TTL or IPv6 hop limit applied to sent packets.
     ///
     /// `None` leaves the platform default unchanged. Values must fit in the
@@ -216,7 +279,8 @@ pub enum NegotiationPolicy {
 /// Mode requested during the IRTT open exchange.
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub enum RunMode {
-    /// Open a session and send echo probes for the negotiated run duration.
+    /// Open a probe session. The managed driver runs for the negotiated duration;
+    /// low-level adapters leave sending and stopping to the caller.
     Normal,
     /// Complete negotiation without running the echo probe test.
     NoTest,

crates/irtt-client/src/event.rs

@@ -92,8 +92,9 @@ pub enum ClientEvent {
         seq: u32,
         /// Resolved remote socket address.
         remote: SocketAddr,
-        /// Monotonic deadline at which the probe was scheduled to be sent.
-        scheduled_at: Instant,
+        /// Intended send deadline, supplied by the managed runner.
+        /// Low-level adapters leave this absent.
+        scheduled_at: Option<Instant>,
         /// Paired client wall/monotonic timestamp captured immediately after
         /// the successful UDP send completed. This is the RTT and userspace
         /// upstream one-way-delay fallback endpoint. The operational probe
@@ -106,8 +107,8 @@ pub enum ClientEvent {
         /// scheduler commit work.
         send_call: Duration,
         /// Absolute difference between the scheduled send time and the
-        /// post-send `sent_at` timestamp above.
-        timer_error: Duration,
+        /// post-send `sent_at` timestamp above; absent for low-level sends.
+        timer_error: Option<Duration>,
     },
 
     /// First in-window reply for a pending echo request.
@@ -260,6 +261,19 @@ pub struct RttSample {
 /// processing time or comparing wall-clock timestamps from different hosts. It
 /// should not be used to represent raw elapsed wall-clock or monotonic time,
 /// which is non-negative and represented by [`Duration`].
+///
+/// # Example
+///
+/// Signed timing values retain a negative result instead of clamping clock
+/// skew or server processing adjustments to zero:
+///
+/// ```
+/// use irtt_client::SignedDuration;
+///
+/// let adjusted_rtt = SignedDuration::from_nanos(-250_000);
+/// assert!(adjusted_rtt.is_negative());
+/// assert_eq!(adjusted_rtt.as_micros(), -250);
+/// ```
 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
 pub struct SignedDuration {
     ns: i128,

crates/irtt-client/src/lib.rs

@@ -18,7 +18,10 @@
 //! wants full control over its own event loop, should start from. With the
 //! `tokio` feature, `AsyncClient` provides the corresponding low-level Tokio
 //! adapter for a caller that owns a runtime and drives socket readiness
-//! itself. [`managed`] sits above both: `ManagedClientTask` /
+//! itself. Both adapters send one probe whenever called; callers own cadence
+//! and run duration, using `negotiated_params()` after Open. [`managed`] owns
+//! negotiated-interval scheduling, finite runs, and staggered/burst pacing:
+//! `ManagedClientTask` /
 //! `ManagedClientHandle` (`tokio` feature) run and control one or more
 //! targets under a Tokio runtime, and `BlockingManagedClient` (`tokio`
 //! feature) wraps that in a synchronous owner backed by its own dedicated

crates/irtt-client/src/managed/blocking.rs

@@ -157,22 +157,14 @@ impl BlockingManagedClient {
     }
 
     fn join_worker(&mut self) -> Result<ManagedOutcome, BlockingManagedJoinError> {
-        join_worker(
-            self.worker
-                .take()
-                .expect("blocking managed worker is joined at most once"),
-        )
+        self.worker
+            .take()
+            .expect("blocking managed worker is joined at most once")
+            .join()
+            .map_err(|_| BlockingManagedJoinError::WorkerPanicked)
     }
 }
 
-pub(super) fn join_worker(
-    worker: JoinHandle<ManagedOutcome>,
-) -> Result<ManagedOutcome, BlockingManagedJoinError> {
-    worker
-        .join()
-        .map_err(|_| BlockingManagedJoinError::WorkerPanicked)
-}
-
 impl Drop for BlockingManagedClient {
     fn drop(&mut self) {
         if self.worker.is_some() {

crates/irtt-client/src/managed/mod.rs

@@ -16,5 +16,5 @@ pub use model::*;
 #[cfg(feature = "tokio")]
 pub use task::*;
 
-#[cfg(all(feature = "tokio", test))]
-mod blocking_tests;
+#[cfg(feature = "tokio")]
+mod schedule;

crates/irtt-client/src/managed/model.rs

@@ -449,199 +449,3 @@ pub(crate) fn classify_client_error(
         message: Arc::from(error.to_string()),
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use std::{collections::TryReserveError, io};
-
-    use super::*;
-
-    fn io_error() -> io::Error {
-        io::Error::other("boom")
-    }
-
-    fn try_reserve_error() -> TryReserveError {
-        Vec::<u8>::new().try_reserve(usize::MAX).unwrap_err()
-    }
-
-    fn classification_cases() -> Vec<(ClientError, ManagedTargetFailureKind)> {
-        vec![
-            (
-                ClientError::Resolve {
-                    addr: "example.invalid:2112".to_owned(),
-                },
-                ManagedTargetFailureKind::Resolve,
-            ),
-            (
-                ClientError::Socket(io_error()),
-                ManagedTargetFailureKind::Socket,
-            ),
-            (
-                ClientError::DatagramLengthMismatch {
-                    expected: 64,
-                    actual: 32,
-                },
-                ManagedTargetFailureKind::Socket,
-            ),
-            (
-                ClientError::SocketOption {
-                    operation: "set read timeout",
-                    remote: "127.0.0.1:2112".parse().unwrap(),
-                    source: io_error(),
-                },
-                ManagedTargetFailureKind::SocketOption,
-            ),
-            (
-                ClientError::ReadTimeoutRestore { source: io_error() },
-                ManagedTargetFailureKind::SocketOption,
-            ),
-            (
-                ClientError::Protocol(irtt_proto::ProtoError::BadMagic),
-                ManagedTargetFailureKind::Protocol,
-            ),
-            (
-                ClientError::ProtocolVersionMismatch {
-                    requested: 1,
-                    received: 2,
-                },
-                ManagedTargetFailureKind::Protocol,
-            ),
-            (ClientError::ZeroToken, ManagedTargetFailureKind::Protocol),
-            (
-                ClientError::UnexpectedNoTestReply,
-                ManagedTargetFailureKind::Protocol,
-            ),
-            (
-                ClientError::NonZeroNoTestToken { token: 7 },
-                ManagedTargetFailureKind::Protocol,
-            ),
-            (
-                ClientError::ServerRejected,
-                ManagedTargetFailureKind::Protocol,
-            ),
-            (
-                ClientError::NegotiationRejected {
-                    reason: "duration".to_owned(),
-                },
-                ManagedTargetFailureKind::Protocol,
-            ),
-            (ClientError::OpenTimeout, ManagedTargetFailureKind::Timeout),
-            (
-                ClientError::InvalidConfig {
-                    reason: "interval".to_owned(),
-                },
-                ManagedTargetFailureKind::Configuration,
-            ),
-            (
-                ClientError::OpenTimeoutTooSmall {
-                    timeout: Duration::from_millis(1),
-                    minimum: Duration::from_millis(10),
-                },
-                ManagedTargetFailureKind::Configuration,
-            ),
-            (
-                ClientError::NoOpenTimeouts,
-                ManagedTargetFailureKind::Configuration,
-            ),
-            (
-                ClientError::AllocationFailed {
-                    operation: "pending probes",
-                    source: try_reserve_error(),
-                },
-                ManagedTargetFailureKind::ResourceExhausted,
-            ),
-            (
-                ClientError::CounterOverflow {
-                    counter: "packets_sent",
-                },
-                ManagedTargetFailureKind::ResourceExhausted,
-            ),
-            (
-                ClientError::DurationOverflow,
-                ManagedTargetFailureKind::ResourceExhausted,
-            ),
-            (
-                ClientError::PendingLimitExceeded { limit: 8 },
-                ManagedTargetFailureKind::ResourceExhausted,
-            ),
-            (
-                ClientError::NoTokioRuntime,
-                ManagedTargetFailureKind::InvalidState,
-            ),
-            (ClientError::NotOpen, ManagedTargetFailureKind::InvalidState),
-            (
-                ClientError::AlreadyOpen,
-                ManagedTargetFailureKind::InvalidState,
-            ),
-            (
-                ClientError::AlreadyCompleted,
-                ManagedTargetFailureKind::InvalidState,
-            ),
-            (
-                ClientError::AlreadyClosed,
-                ManagedTargetFailureKind::InvalidState,
-            ),
-            (
-                ClientError::StalePreparedProbe {
-                    prepared_seq: 3,
-                    next_wire_seq: 4,
-                },
-                ManagedTargetFailureKind::InvalidState,
-            ),
-            (
-                ClientError::PendingSequenceCollision { seq: 9 },
-                ManagedTargetFailureKind::InvalidState,
-            ),
-        ]
-    }
-
-    #[test]
-    fn every_client_error_classifies_to_its_documented_kind() {
-        for (error, expected) in classification_cases() {
-            let failure = classify_client_error(ManagedTargetFailurePhase::Opening, &error);
-            assert_eq!(
-                failure.kind, expected,
-                "unexpected classification for {error:?}"
-            );
-            assert_eq!(failure.phase, ManagedTargetFailurePhase::Opening);
-            assert_eq!(&*failure.message, error.to_string());
-        }
-    }
-
-    #[test]
-    fn classification_preserves_the_reported_phase() {
-        for phase in [
-            ManagedTargetFailurePhase::Connecting,
-            ManagedTargetFailurePhase::Opening,
-            ManagedTargetFailurePhase::Sending,
-            ManagedTargetFailurePhase::Receiving,
-            ManagedTargetFailurePhase::Timing,
-            ManagedTargetFailurePhase::Closing,
-        ] {
-            let failure = classify_client_error(phase, &ClientError::OpenTimeout);
-            assert_eq!(failure.phase, phase);
-        }
-    }
-
-    #[test]
-    fn phase_and_kind_display_without_debug_spelling() {
-        assert_eq!(
-            ManagedTargetFailurePhase::Connecting.to_string(),
-            "connecting"
-        );
-        assert_eq!(ManagedTargetFailurePhase::Closing.to_string(), "closing");
-        assert_eq!(
-            ManagedTargetFailureKind::SocketOption.to_string(),
-            "socket option"
-        );
-        assert_eq!(
-            ManagedTargetFailureKind::ResourceExhausted.to_string(),
-            "resource exhausted"
-        );
-        assert_eq!(
-            ManagedTargetFailureKind::InvalidState.to_string(),
-            "invalid state"
-        );
-        assert_eq!(ManagedTargetFailureKind::Other.to_string(), "other");
-    }
-}

crates/irtt-client/src/managed/schedule.rs

@@ -0,0 +1,154 @@
+use std::time::{Duration, Instant};
+
+use crate::{error::ClientError, session::NegotiatedParams};
+
+#[derive(Debug)]
+pub(crate) struct ProbeSchedule {
+    end_at: Option<Instant>,
+    interval: Duration,
+    next_send_at: Option<Instant>,
+}
+
+#[derive(Debug)]
+pub(crate) struct ScheduleCommit {
+    pub(crate) scheduled_at: Instant,
+    pub(crate) next_send_at: Option<Instant>,
+}
+
+impl ProbeSchedule {
+    pub(crate) fn new(
+        start_at: Instant,
+        negotiated: &NegotiatedParams,
+    ) -> Result<Self, ClientError> {
+        let interval_ns = u64::try_from(negotiated.params.interval_ns)
+            .expect("validated positive negotiated interval");
+        let interval = Duration::from_nanos(interval_ns);
+        let end_at = if negotiated.params.duration_ns > 0 {
+            let duration_ns = u64::try_from(negotiated.params.duration_ns)
+                .expect("validated positive negotiated duration");
+            Some(
+                start_at
+                    .checked_add(Duration::from_nanos(duration_ns))
+                    .ok_or_else(|| ClientError::NegotiationRejected {
+                        reason: "duration is too large to schedule".to_owned(),
+                    })?,
+            )
+        } else {
+            None
+        };
+
+        Ok(Self {
+            end_at,
+            interval,
+            next_send_at: Some(start_at),
+        })
+    }
+
+    pub(crate) fn next_send_deadline(&self) -> Option<Instant> {
+        self.next_send_at
+    }
+
+    pub(crate) fn interval(&self) -> Duration {
+        self.interval
+    }
+
+    pub(crate) fn permit_probe_at(&mut self, now: Instant) -> bool {
+        if self.next_send_at.is_none() {
+            return false;
+        }
+        if self.end_at.is_some_and(|end| now >= end) {
+            self.next_send_at = None;
+            return false;
+        }
+        true
+    }
+
+    pub(crate) fn preflight_managed_commit(
+        &self,
+        scheduled_at: Instant,
+        permission_at: Instant,
+    ) -> Result<ScheduleCommit, ClientError> {
+        let (scheduled_at, next_send_at) =
+            advance_cadence(scheduled_at, self.interval, permission_at)?;
+        Ok(ScheduleCommit {
+            scheduled_at,
+            next_send_at: if self.end_at.is_some_and(|end| next_send_at >= end) {
+                None
+            } else {
+                Some(next_send_at)
+            },
+        })
+    }
+
+    pub(crate) fn commit(&mut self, commit: ScheduleCommit) {
+        self.next_send_at = commit.next_send_at;
+    }
+
+    /// Reclaim slots crossed while a successful socket submission was in flight.
+    /// This follows the send commit; it never advances a failed submission.
+    pub(crate) fn skip_missed_slots_at(&mut self, now: Instant) -> Result<(), ClientError> {
+        if let Some(deadline) = self.next_send_at.filter(|deadline| *deadline <= now) {
+            let commit = self.preflight_managed_commit(deadline, now)?;
+            self.commit(commit);
+        }
+        Ok(())
+    }
+
+    pub(crate) fn is_finished(&self) -> bool {
+        self.next_send_at.is_none()
+    }
+}
+
+pub(crate) fn advance_cadence(
+    deadline: Instant,
+    interval: Duration,
+    now: Instant,
+) -> Result<(Instant, Instant), ClientError> {
+    if interval.is_zero() {
+        return Err(ClientError::InvalidConfig {
+            reason: "probe interval must be greater than zero".to_owned(),
+        });
+    }
+
+    let elapsed_slots = now
+        .checked_duration_since(deadline)
+        .map_or(0, |elapsed| elapsed.as_nanos() / interval.as_nanos());
+    let scheduled_offset = duration_from_nanos(
+        interval
+            .as_nanos()
+            .checked_mul(elapsed_slots)
+            .ok_or(ClientError::DurationOverflow)?,
+    )?;
+    let next_offset = duration_from_nanos(
+        interval
+            .as_nanos()
+            .checked_mul(
+                elapsed_slots
+                    .checked_add(1)
+                    .ok_or(ClientError::DurationOverflow)?,
+            )
+            .ok_or(ClientError::DurationOverflow)?,
+    )?;
+    let scheduled_at = deadline
+        .checked_add(scheduled_offset)
+        .ok_or(ClientError::DurationOverflow)?;
+    let next_at = deadline
+        .checked_add(next_offset)
+        .ok_or(ClientError::DurationOverflow)?;
+    Ok((scheduled_at, next_at))
+}
+
+fn duration_from_nanos(nanos: u128) -> Result<Duration, ClientError> {
+    const NANOS_PER_SECOND: u128 = 1_000_000_000;
+    let seconds =
+        u64::try_from(nanos / NANOS_PER_SECOND).map_err(|_| ClientError::DurationOverflow)?;
+    let subsec_nanos = u32::try_from(nanos % NANOS_PER_SECOND)
+        .expect("nanosecond remainder is always less than one second");
+    Ok(Duration::new(seconds, subsec_nanos))
+}
+
+pub(crate) fn instant_abs_diff(left: Instant, right: Instant) -> Duration {
+    left.checked_duration_since(right)
+        .or_else(|| right.checked_duration_since(left))
+        .unwrap_or(Duration::ZERO)
+}

crates/irtt-client/src/managed/task.rs

@@ -25,6 +25,8 @@ use crate::{
     ClientConfig, ClientError, ClientEvent, OpenOutcome,
 };
 
+use super::schedule::{instant_abs_diff, ProbeSchedule};
+
 use super::{
     classify_client_error, ManagedClientConfig, ManagedCommandAcknowledgement,
     ManagedCommandApplyError, ManagedCommandError, ManagedCompletionPolicy, ManagedConfigError,
@@ -44,6 +46,42 @@ const POST_DEADLINE_RECEIVE_BUDGET: usize = TARGET_WORK_BUDGET;
 const MAX_BROADCAST_CHANNEL_CAPACITY: usize = usize::MAX >> 1;
 
 /// Entry point for constructing a unified Tokio managed task.
+///
+/// # Example
+///
+/// Construct the task and its separate control handle, subscribe before
+/// starting the task, then run it under the caller's Tokio runtime. A reachable
+/// server is required at runtime, so this example only type-checks.
+///
+/// ```no_run
+/// use irtt_client::{ClientConfig, ClientEvent};
+/// use irtt_client::managed::{
+///     ManagedClient, ManagedClientConfig, ManagedEvent, ManagedTargetConfig,
+/// };
+///
+/// # async fn run() -> Result<(), Box<dyn std::error::Error>> {
+/// let config = ManagedClientConfig {
+///     client: ClientConfig {
+///         duration: Some(std::time::Duration::from_secs(10)),
+///         ..ClientConfig::default()
+///     },
+///     ..ManagedClientConfig::default()
+/// };
+/// let targets = vec![ManagedTargetConfig::new("edge", "127.0.0.1:2112")];
+/// let (task, handle) = ManagedClient::task(config, targets)?;
+/// let mut events = handle.subscribe()?;
+/// let driver = tokio::spawn(task);
+///
+/// while let Ok(event) = events.recv().await {
+///     if let ManagedEvent::Client { event: ClientEvent::EchoReply { .. }, .. } = event {
+///         println!("received a probe reply");
+///     }
+/// }
+/// let outcome = driver.await?;
+/// println!("run ended: {:?}", outcome.end_reason);
+/// # Ok(())
+/// # }
+/// ```
 #[derive(Debug, Default)]
 pub struct ManagedClient;
 
@@ -139,73 +177,6 @@ pub struct ManagedClientHandle {
     max_live_target_generations: usize,
     status: watch::Receiver<Arc<ManagedStatus>>,
     events: broadcast::WeakSender<ManagedEvent>,
-    #[cfg(test)]
-    update_submission_hook: Option<Arc<UpdateSubmissionTestHook>>,
-}
-
-#[cfg(test)]
-#[derive(Default)]
-struct UpdateSubmissionTestHook {
-    state: std::sync::Mutex<UpdateSubmissionTestState>,
-    arrived: std::sync::Condvar,
-    released: std::sync::Condvar,
-}
-
-#[cfg(test)]
-#[derive(Default)]
-struct UpdateSubmissionTestState {
-    armed: bool,
-    arrived: bool,
-    released: bool,
-}
-
-#[cfg(test)]
-impl UpdateSubmissionTestHook {
-    fn arm(&self) {
-        self.state
-            .lock()
-            .unwrap_or_else(std::sync::PoisonError::into_inner)
-            .armed = true;
-    }
-
-    fn pause_after_admission(&self) {
-        let mut state = self
-            .state
-            .lock()
-            .unwrap_or_else(std::sync::PoisonError::into_inner);
-        if !state.armed {
-            return;
-        }
-        state.arrived = true;
-        self.arrived.notify_all();
-        while !state.released {
-            state = self
-                .released
-                .wait(state)
-                .unwrap_or_else(std::sync::PoisonError::into_inner);
-        }
-    }
-
-    fn wait_until_arrived(&self) {
-        let state = self
-            .state
-            .lock()
-            .unwrap_or_else(std::sync::PoisonError::into_inner);
-        let (state, timeout) = self
-            .arrived
-            .wait_timeout_while(state, Duration::from_secs(2), |state| !state.arrived)
-            .unwrap_or_else(std::sync::PoisonError::into_inner);
-        assert!(state.arrived && !timeout.timed_out());
-    }
-
-    fn release(&self) {
-        let mut state = self
-            .state
-            .lock()
-            .unwrap_or_else(std::sync::PoisonError::into_inner);
-        state.released = true;
-        self.released.notify_all();
-    }
 }
 
 impl fmt::Debug for ManagedClientHandle {
@@ -267,11 +238,6 @@ impl ManagedClientHandle {
             });
         }
 
-        #[cfg(test)]
-        if let Some(hook) = &self.update_submission_hook {
-            hook.pause_after_admission();
-        }
-
         // Observing `Open` only permits attempting submission. A successful
         // `try_send` transfers command ownership to the driver. A concurrent
         // stop may move admission to `Stopping` before this send, allowing the
@@ -301,6 +267,19 @@ pub struct ManagedCommandReceipt {
     receiver: oneshot::Receiver<Result<ManagedCommandAcknowledgement, ManagedCommandApplyError>>,
 }
 
+impl ManagedCommandReceipt {
+    /// Block until the target-set transaction is applied or rejected.
+    ///
+    /// This is for synchronous callers such as [`crate::managed::BlockingManagedClient`]. It
+    /// must not be called from an asynchronous runtime; use the [`Future`]
+    /// implementation there instead.
+    pub fn blocking_wait(self) -> Result<ManagedCommandAcknowledgement, ManagedCommandApplyError> {
+        self.receiver
+            .blocking_recv()
+            .unwrap_or(Err(ManagedCommandApplyError::AcknowledgementDisconnected))
+    }
+}
+
 impl Future for ManagedCommandReceipt {
     type Output = Result<ManagedCommandAcknowledgement, ManagedCommandApplyError>;
     fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
@@ -351,10 +330,6 @@ impl Future for ManagedStopReceipt {
 type ConnectFuture =
     Pin<Box<dyn Future<Output = Result<AsyncClient, ClientError>> + Send + 'static>>;
 type WakeFuture = Pin<Box<dyn Future<Output = Option<watch::Receiver<()>>> + Send + 'static>>;
-#[cfg(test)]
-type EventObservations = Arc<std::sync::Mutex<Vec<(ManagedEvent, Arc<ManagedStatus>)>>>;
-#[cfg(test)]
-type StaggerObservations = Arc<std::sync::Mutex<Vec<(usize, Duration)>>>;
 
 fn arm_wake(mut receiver: watch::Receiver<()>) -> WakeFuture {
     Box::pin(async move {
@@ -455,6 +430,7 @@ impl TargetCounters {
 }
 
 struct TargetRuntime {
+    schedule: Option<ProbeSchedule>,
     instance: TargetInstance,
     config: ManagedTargetConfig,
     desired: bool,
@@ -473,17 +449,7 @@ impl TargetRuntime {
     /// The client owns `packets_sent`; this runtime only mirrors it so a
     /// terminal outcome can report it after the client is gone.
     fn sync_packets_sent(&mut self, client: &AsyncClient) {
-        self.record_packets_sent(client.packets_sent());
-    }
-
-    /// Adopt an already-read authoritative sent count.
-    fn record_packets_sent(&mut self, packets_sent: u64) {
-        self.counters.packets_sent = packets_sent;
-    }
-
-    /// Account for one client event against this target's durable counters.
-    fn observe(&mut self, event: &ClientEvent) {
-        self.counters.observe(event);
+        self.counters.packets_sent = client.packets_sent();
     }
 
     /// Build this target's durable outcome.
@@ -646,6 +612,8 @@ enum OpenSessionFailureCleanup {
 /// The sole authoritative zero-or-many target driver.
 #[must_use = "ManagedClientTask must be awaited or deliberately dropped"]
 pub struct ManagedClientTask {
+    #[cfg(test)]
+    timeout_inspections: std::cell::RefCell<Vec<usize>>,
     state: DriverState,
     lifecycle: ManagedLifecycle,
     config: ManagedClientConfig,
@@ -668,24 +636,6 @@ pub struct ManagedClientTask {
     final_outcome: Option<Arc<ManagedOutcome>>,
     next_generation: u64,
     applied_command_sequence: u64,
-    #[cfg(test)]
-    event_observations: Option<EventObservations>,
-    #[cfg(test)]
-    stagger_observations: Option<StaggerObservations>,
-    #[cfg(test)]
-    drain_test_hook: DrainTestHook,
-    #[cfg(test)]
-    timeout_inspections: usize,
-    #[cfg(test)]
-    deadline_inspections: usize,
-}
-
-#[cfg(test)]
-#[derive(Default)]
-struct DrainTestHook {
-    defer_work_until_deadline: bool,
-    fail_receive: bool,
-    fail_close: bool,
 }
 
 impl ManagedClientTask {
@@ -696,13 +646,6 @@ impl ManagedClientTask {
     }
 
     fn publish_event(&self, event: ManagedEvent) {
-        #[cfg(test)]
-        if let Some(observations) = &self.event_observations {
-            observations
-                .lock()
-                .unwrap_or_else(std::sync::PoisonError::into_inner)
-                .push((event.clone(), Arc::clone(&self.resources().status.borrow())));
-        }
         if let Some(events) = &self.resources().events {
             let _ = events.send(event);
         }
@@ -785,7 +728,7 @@ impl ManagedClientTask {
 
     fn publish_client_events(&mut self, index: usize, events: Vec<ClientEvent>) {
         for event in events {
-            self.targets[index].observe(&event);
+            self.targets[index].counters.observe(&event);
             self.publish_event(ManagedEvent::Client {
                 target: self.targets[index].instance.clone(),
                 event,
@@ -942,6 +885,7 @@ impl ManagedClientTask {
             };
             created_instances.push(instance.clone());
             self.targets.push(TargetRuntime {
+                schedule: None,
                 instance,
                 server_addr: Arc::from(planned.target.server_addr.clone()),
                 config: planned.target,
@@ -1194,7 +1138,25 @@ impl ManagedClientTask {
                         self.targets[index].state = TargetState::Opening { client, open };
                         false
                     }
-                    Poll::Ready(Ok(OpenOutcome::Started { event, .. })) => {
+                    Poll::Ready(Ok(OpenOutcome::Started {
+                        event, negotiated, ..
+                    })) => {
+                        let ClientEvent::SessionStarted { at: opened_at, .. } = &event else {
+                            unreachable!("Started carries SessionStarted");
+                        };
+                        match ProbeSchedule::new(opened_at.mono, &negotiated) {
+                            Ok(schedule) => self.targets[index].schedule = Some(schedule),
+                            Err(error) => {
+                                return self.begin_open_session_failure(
+                                    index,
+                                    client,
+                                    ManagedTargetFailurePhase::Timing,
+                                    error,
+                                    now,
+                                    OpenSessionFailureCleanup::Close,
+                                )
+                            }
+                        }
                         self.publish_client_events(index, vec![event]);
                         if self.state == DriverState::Stopping
                             || self.effective_retirement(index).is_some()
@@ -1291,7 +1253,15 @@ impl ManagedClientTask {
                     self.finish_target(index, ManagedTargetEndReason::PeerClosed, None);
                     return false;
                 }
-                if client.is_run_complete() {
+                if self.targets[index]
+                    .schedule
+                    .as_mut()
+                    .is_some_and(|schedule| {
+                        schedule.permit_probe_at(now);
+                        schedule.is_finished()
+                    })
+                    && !client.has_pending_probes()
+                {
                     self.targets[index].sync_packets_sent(&client);
                     return self.begin_drain(
                         index,
@@ -1311,22 +1281,6 @@ impl ManagedClientTask {
                 mut cleanup_failure,
                 mut post_deadline_receives_remaining,
             } => {
-                #[cfg(test)]
-                let defer_work = self.drain_test_hook.defer_work_until_deadline && now < deadline;
-                #[cfg(not(test))]
-                let defer_work = false;
-                if defer_work {
-                    self.targets[index].state = TargetState::Draining {
-                        client,
-                        drain_started_at,
-                        deadline,
-                        primary_end,
-                        cleanup_failure,
-                        post_deadline_receives_remaining,
-                    };
-                    return false;
-                }
-
                 if client
                     .next_probe_timeout_deadline()
                     .is_some_and(|timeout| timeout <= now)
@@ -1342,10 +1296,6 @@ impl ManagedClientTask {
                     return true;
                 }
 
-                #[cfg(test)]
-                let injected_receive_failure = self.take_drain_receive_failure();
-                #[cfg(not(test))]
-                let injected_receive_failure = None;
                 let mut retained_state_changed = false;
                 let received = match client.poll_recv(cx) {
                     Poll::Pending => false,
@@ -1362,13 +1312,7 @@ impl ManagedClientTask {
                         return self.begin_close(index, client, primary_end, cleanup_failure, now);
                     }
                 };
-                if let Some(error) = injected_receive_failure {
-                    self.targets[index].sync_packets_sent(&client);
-                    cleanup_failure.get_or_insert_with(|| {
-                        classify_client_error(ManagedTargetFailurePhase::Receiving, &error)
-                    });
-                    return self.begin_close(index, client, primary_end, cleanup_failure, now);
-                }
+
                 if client.is_peer_closed() {
                     self.targets[index].sync_packets_sent(&client);
                     self.finish_target(index, ManagedTargetEndReason::PeerClosed, cleanup_failure);
@@ -1446,17 +1390,7 @@ impl ManagedClientTask {
                 Poll::Ready(Ok(events)) => {
                     self.targets[index].sync_packets_sent(&client);
                     self.publish_client_events(index, events);
-                    #[cfg(test)]
-                    let injected_close_failure = self.take_drain_close_failure().map(|error| {
-                        classify_client_error(ManagedTargetFailurePhase::Closing, &error)
-                    });
-                    #[cfg(not(test))]
-                    let injected_close_failure = None;
-                    self.finish_target(
-                        index,
-                        primary_end,
-                        cleanup_failure.or(injected_close_failure),
-                    );
+                    self.finish_target(index, primary_end, cleanup_failure);
                     false
                 }
                 Poll::Ready(Err(error)) => {
@@ -1537,26 +1471,6 @@ impl ManagedClientTask {
         true
     }
 
-    #[cfg(test)]
-    fn take_drain_receive_failure(&mut self) -> Option<ClientError> {
-        if !mem::take(&mut self.drain_test_hook.fail_receive) {
-            return None;
-        }
-        Some(ClientError::Socket(std::io::Error::other(
-            "injected drain receive failure",
-        )))
-    }
-
-    #[cfg(test)]
-    fn take_drain_close_failure(&mut self) -> Option<ClientError> {
-        if !mem::take(&mut self.drain_test_hook.fail_close) {
-            return None;
-        }
-        Some(ClientError::Socket(std::io::Error::other(
-            "injected drain close failure",
-        )))
-    }
-
     fn active_count(&self) -> usize {
         self.targets
             .iter()
@@ -1564,23 +1478,25 @@ impl ManagedClientTask {
             .count()
     }
 
-    fn active_stagger_spacing(&self) -> Option<(usize, Duration)> {
+    fn active_stagger_spacing(&self) -> Option<Duration> {
         let mut active = 0;
         let mut minimum: Option<Duration> = None;
         for target in &self.targets {
             if !target.desired || target.retirement.is_some() {
                 continue;
             }
-            let TargetState::Active { client } = &target.state else {
+            let TargetState::Active { .. } = &target.state else {
                 continue;
             };
             active += 1;
-            let interval = client
-                .probe_interval()
-                .expect("active managed targets have a committed probe schedule");
+            let interval = target
+                .schedule
+                .as_ref()
+                .expect("active managed targets have a probe schedule")
+                .interval();
             minimum = minimum.into_iter().chain(Some(interval)).min();
         }
-        minimum.map(|interval| (active, stagger_spacing(interval, active)))
+        minimum.map(|interval| stagger_spacing(interval, active))
     }
 
     fn stagger_target_added(&mut self, now: Instant) {
@@ -1591,7 +1507,7 @@ impl ManagedClientTask {
         let candidate = self
             .last_stagger_send
             .zip(self.active_stagger_spacing())
-            .and_then(|(last, (_, spacing))| last.checked_add(spacing))
+            .and_then(|(last, spacing)| last.checked_add(spacing))
             .filter(|gate| *gate > now);
         self.send_gate = candidate.map(|candidate| existing.min(candidate));
     }
@@ -1600,24 +1516,44 @@ impl ManagedClientTask {
         self.send_gate = self.send_gate.filter(|gate| *gate > now);
     }
 
+    /// The next stagger gate after a send was accepted at `accepted_at`.
+    ///
+    /// The gate advances on its **own** cadence rather than being re-anchored
+    /// on every observed accept time. Anchoring on `accepted_at` folds each
+    /// send's wakeup latency into the next slot and then into every slot after
+    /// it, so the gate — and with it the whole group's send cadence — drifts
+    /// later without bound while the per-target schedules stay on their
+    /// absolute grid. The drift is not hypothetical: it shows up as a
+    /// monotonically growing `EchoSent::timer_error` and, once it exceeds one
+    /// interval, as probe slots the schedule then skips.
+    ///
+    /// `accepted_at` is still the anchor in the two cases where continuing the
+    /// old cadence would be wrong: there is no previous gate, or the pacer has
+    /// fallen a full slot behind it. Re-anchoring there is what keeps a gate
+    /// stranded in the past from releasing a burst of catch-up sends once the
+    /// group starts moving again.
+    fn next_stagger_gate(&self, spacing: Duration, accepted_at: Instant) -> Option<Instant> {
+        let base = match self.send_gate {
+            Some(gate) if gate <= accepted_at && accepted_at.duration_since(gate) < spacing => gate,
+            _ => accepted_at,
+        };
+        base.checked_add(spacing)
+    }
+
     fn record_stagger_acceptance(
         &mut self,
         result: SendResult,
-        stagger_spacing: Option<(usize, Duration)>,
+        stagger_spacing: Option<Duration>,
         accepted_at: Instant,
     ) {
         if !result.accepted() {
             return;
         }
-        let Some((_active, spacing)) = stagger_spacing else {
+        let Some(spacing) = stagger_spacing else {
             return;
         };
         self.last_stagger_send = Some(accepted_at);
-        self.send_gate = accepted_at.checked_add(spacing);
-        #[cfg(test)]
-        if let Some(observations) = &self.stagger_observations {
-            observations.lock().unwrap().push((_active, spacing));
-        }
+        self.send_gate = self.next_stagger_gate(spacing, accepted_at);
     }
 
     fn poll_one_send(
@@ -1625,7 +1561,7 @@ impl ManagedClientTask {
         index: usize,
         cx: &mut Context<'_>,
         now: Instant,
-        stagger_spacing: Option<(usize, Duration)>,
+        stagger_spacing: Option<Duration>,
     ) -> SendResult {
         if !self.targets[index].desired || self.targets[index].retirement.is_some() {
             self.targets[index].send_waiting = false;
@@ -1636,6 +1572,9 @@ impl ManagedClientTask {
             self.targets[index].state = state;
             return SendResult::NotAttempted;
         };
+        // A burst pass may span several slots; validate this target against
+        // fresh time rather than the pass's earlier scheduling snapshot.
+        let now = now.max(Instant::now());
         if client
             .next_probe_timeout_deadline()
             .is_some_and(|deadline| deadline <= now)
@@ -1644,7 +1583,21 @@ impl ManagedClientTask {
             self.targets[index].state = TargetState::Active { client };
             return SendResult::NotAttempted;
         }
-        if client
+        let schedule = self.targets[index]
+            .schedule
+            .as_mut()
+            .expect("active managed targets have a probe schedule");
+        if !schedule.permit_probe_at(now) {
+            self.targets[index].send_waiting = false;
+            if client.has_pending_probes() {
+                self.targets[index].state = TargetState::Active { client };
+                return SendResult::NotAttempted;
+            }
+            self.targets[index].sync_packets_sent(&client);
+            self.begin_drain(index, client, ManagedTargetEndReason::TestComplete, now);
+            return SendResult::Ready { accepted: false };
+        }
+        if schedule
             .next_send_deadline()
             .is_none_or(|deadline| deadline > now)
         {
@@ -1652,8 +1605,25 @@ impl ManagedClientTask {
             self.targets[index].state = TargetState::Active { client };
             return SendResult::NotAttempted;
         }
+        let schedule = self.targets[index].schedule.as_ref().unwrap();
+        let commit =
+            match schedule.preflight_managed_commit(schedule.next_send_deadline().unwrap(), now) {
+                Ok(commit) => commit,
+                Err(error) => {
+                    self.begin_open_session_failure(
+                        index,
+                        client,
+                        ManagedTargetFailurePhase::Timing,
+                        error,
+                        now,
+                        OpenSessionFailureCleanup::Drain,
+                    );
+                    return SendResult::Failed { accepted: false };
+                }
+            };
+        let scheduled_at = commit.scheduled_at;
         let before = client.packets_sent();
-        let result = client.poll_send_probe(cx);
+        let mut result = client.poll_send_probe(cx);
         let after = client.packets_sent();
         let accepted = after > before;
         let send_result = match &result {
@@ -1662,11 +1632,38 @@ impl ManagedClientTask {
             Poll::Ready(Err(_)) => SendResult::Failed { accepted },
         };
         self.record_stagger_acceptance(send_result, stagger_spacing, Instant::now());
-        let schedule_error = accepted
-            .then(|| client.skip_missed_probe_slots_at(Instant::now()))
-            .transpose()
-            .err();
-        self.targets[index].record_packets_sent(after);
+        if accepted {
+            self.targets[index]
+                .schedule
+                .as_mut()
+                .unwrap()
+                .commit(commit);
+            if let Poll::Ready(Ok(events)) = &mut result {
+                for event in events {
+                    if let ClientEvent::EchoSent {
+                        scheduled_at: intended,
+                        sent_at,
+                        timer_error,
+                        ..
+                    } = event
+                    {
+                        *intended = Some(scheduled_at);
+                        *timer_error = Some(instant_abs_diff(sent_at.mono, scheduled_at));
+                    }
+                }
+            }
+        }
+        let schedule_error = if accepted {
+            self.targets[index]
+                .schedule
+                .as_mut()
+                .unwrap()
+                .skip_missed_slots_at(Instant::now())
+                .err()
+        } else {
+            None
+        };
+        self.targets[index].counters.packets_sent = after;
         match result {
             Poll::Pending => {
                 self.targets[index].send_waiting = true;
@@ -1681,7 +1678,7 @@ impl ManagedClientTask {
                     let TargetState::Active { client } =
                         mem::replace(&mut self.targets[index].state, TargetState::Terminal)
                     else {
-                        unreachable!("probe sender remained active while publishing send events");
+                        unreachable!("sender remained active")
                     };
                     self.begin_open_session_failure(
                         index,
@@ -1696,6 +1693,7 @@ impl ManagedClientTask {
                     SendResult::Ready { accepted }
                 }
             }
+
             Poll::Ready(Err(error)) => {
                 self.targets[index].send_waiting = false;
                 self.begin_open_session_failure(
@@ -1790,10 +1788,6 @@ impl ManagedClientTask {
             }
             let index = self.timeout_cursor;
             self.timeout_cursor = (self.timeout_cursor + 1) % target_len;
-            #[cfg(test)]
-            {
-                self.timeout_inspections += 1;
-            }
             if self.target_has_due_timeout(index, now) {
                 let generation = self.targets[index].instance.generation;
                 let step = self.poll_target_timeout(index, now);
@@ -1841,6 +1835,8 @@ impl ManagedClientTask {
     }
 
     fn target_has_due_timeout(&self, index: usize, now: Instant) -> bool {
+        #[cfg(test)]
+        self.timeout_inspections.borrow_mut().push(index);
         match &self.targets[index].state {
             TargetState::Active { client } => {
                 self.state != DriverState::Stopping
@@ -1849,20 +1845,9 @@ impl ManagedClientTask {
                         .next_probe_timeout_deadline()
                         .is_some_and(|deadline| deadline <= now)
             }
-            TargetState::Draining {
-                client,
-                deadline: _deadline,
-                ..
-            } => {
-                #[cfg(test)]
-                let defer_work = self.drain_test_hook.defer_work_until_deadline && now < *_deadline;
-                #[cfg(not(test))]
-                let defer_work = false;
-                !defer_work
-                    && client
-                        .next_probe_timeout_deadline()
-                        .is_some_and(|timeout| timeout <= now)
-            }
+            TargetState::Draining { client, .. } => client
+                .next_probe_timeout_deadline()
+                .is_some_and(|timeout| timeout <= now),
             _ => false,
         }
     }
@@ -1942,11 +1927,7 @@ impl ManagedClientTask {
             .all(|target| matches!(target.state, TargetState::Terminal))
     }
 
-    fn next_deadline(&mut self) -> Option<Instant> {
-        #[cfg(test)]
-        {
-            self.deadline_inspections += self.targets.len();
-        }
+    fn next_deadline(&self) -> Option<Instant> {
         let mut non_send_deadline = None;
         let mut send_deadline = None;
         for target in &self.targets {
@@ -1959,24 +1940,21 @@ impl ManagedClientTask {
                     if target.desired && target.retirement.is_none() && !target.send_waiting {
                         send_deadline = send_deadline
                             .into_iter()
-                            .chain(client.next_send_deadline())
+                            .chain(
+                                target
+                                    .schedule
+                                    .as_ref()
+                                    .and_then(ProbeSchedule::next_send_deadline),
+                            )
                             .min();
                     }
                 }
                 TargetState::Draining {
                     client, deadline, ..
                 } => {
-                    #[cfg(test)]
-                    let defer_work = self.drain_test_hook.defer_work_until_deadline;
-                    #[cfg(not(test))]
-                    let defer_work = false;
                     non_send_deadline = non_send_deadline
                         .into_iter()
-                        .chain(
-                            (!defer_work)
-                                .then(|| client.next_probe_timeout_deadline())
-                                .flatten(),
-                        )
+                        .chain(client.next_probe_timeout_deadline())
                         .chain(Some(*deadline))
                         .min();
                 }
@@ -2276,6 +2254,7 @@ fn build_task(
             }
         })?;
         runtimes.push(TargetRuntime {
+            schedule: None,
             instance: TargetInstance {
                 id: target.id.clone(),
                 generation,
@@ -2343,6 +2322,8 @@ fn build_task(
         stop: Arc::clone(&stop),
     };
     let task = ManagedClientTask {
+        #[cfg(test)]
+        timeout_inspections: std::cell::RefCell::new(Vec::new()),
         state: DriverState::NotStarted,
         lifecycle: ManagedLifecycle::NotStarted,
         config,
@@ -2365,16 +2346,6 @@ fn build_task(
         final_outcome: None,
         next_generation,
         applied_command_sequence: 0,
-        #[cfg(test)]
-        event_observations: None,
-        #[cfg(test)]
-        stagger_observations: None,
-        #[cfg(test)]
-        drain_test_hook: DrainTestHook::default(),
-        #[cfg(test)]
-        timeout_inspections: 0,
-        #[cfg(test)]
-        deadline_inspections: 0,
     };
     let handle = ManagedClientHandle {
         stop,
@@ -2382,8 +2353,6 @@ fn build_task(
         max_live_target_generations,
         status: status_receiver,
         events: weak_events,
-        #[cfg(test)]
-        update_submission_hook: None,
     };
     Ok((task, handle))
 }
@@ -2426,5 +2395,39 @@ fn close_timeout_failure() -> ManagedTargetFailure {
 }
 
 #[cfg(test)]
-#[path = "tests.rs"]
-mod tests;
+mod tests {
+    use super::*;
+
+    // Poll latency through public events cannot distinguish an O(n) discovery
+    // scan from a bounded scan reliably. This tiny inspection trace measures
+    // work directly, including empty targets, and checks eventual coverage
+    // without asserting a cursor value or a particular visitation order.
+    #[test]
+    fn timeout_discovery_has_bounded_work_and_eventually_visits_every_target() {
+        let count = TIMEOUT_WORK_BUDGET * 2 + 1;
+        let targets = (0..count)
+            .map(|i| ManagedTargetConfig::new(i.to_string(), "127.0.0.1:2112"))
+            .collect();
+        let (mut task, _handle) = ManagedClient::task(
+            ManagedClientConfig {
+                max_live_target_generations: count,
+                ..ManagedClientConfig::default()
+            },
+            targets,
+        )
+        .unwrap();
+        let mut visited = HashSet::new();
+        for _ in 0..count.div_ceil(TIMEOUT_WORK_BUDGET) {
+            task.timeout_inspections.borrow_mut().clear();
+            task.poll_timeout_pass(Instant::now());
+            let inspected = task.timeout_inspections.borrow();
+            assert!(inspected.len() <= TIMEOUT_WORK_BUDGET);
+            visited.extend(inspected.iter().copied());
+        }
+        assert_eq!(
+            visited.len(),
+            count,
+            "timeout discovery must reach all targets"
+        );
+    }
+}

crates/irtt-client/src/metadata.rs

@@ -56,180 +56,3 @@ impl From<ReceiveMeta> for PacketMeta {
         }
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use std::time::{Duration, SystemTime};
-
-    use super::{ReceiveMeta, MAX_KERNEL_RX_LAG};
-    use crate::event::PacketMeta;
-
-    fn userspace_wall() -> SystemTime {
-        SystemTime::UNIX_EPOCH + Duration::from_secs(1_700_000_000)
-    }
-
-    fn meta_with_kernel_rx(kernel_rx_timestamp: SystemTime) -> ReceiveMeta {
-        ReceiveMeta {
-            traffic_class: None,
-            kernel_rx_timestamp: Some(kernel_rx_timestamp),
-        }
-    }
-
-    #[test]
-    fn preferred_receive_wall_without_kernel_timestamp_uses_userspace_sample() {
-        let userspace = userspace_wall();
-
-        assert_eq!(
-            ReceiveMeta::default().preferred_receive_wall(userspace),
-            userspace
-        );
-    }
-
-    #[test]
-    fn preferred_receive_wall_uses_plausible_earlier_kernel_timestamp() {
-        let userspace = userspace_wall();
-        let kernel = userspace - Duration::from_micros(80);
-
-        assert_eq!(
-            meta_with_kernel_rx(kernel).preferred_receive_wall(userspace),
-            kernel
-        );
-    }
-
-    #[test]
-    fn preferred_receive_wall_accepts_kernel_timestamp_equal_to_userspace_sample() {
-        let userspace = userspace_wall();
-
-        assert_eq!(
-            meta_with_kernel_rx(userspace).preferred_receive_wall(userspace),
-            userspace
-        );
-    }
-
-    #[test]
-    fn preferred_receive_wall_rejects_kernel_timestamp_later_than_userspace_sample() {
-        let userspace = userspace_wall();
-        let kernel = userspace + Duration::from_nanos(1);
-
-        assert_eq!(
-            meta_with_kernel_rx(kernel).preferred_receive_wall(userspace),
-            userspace
-        );
-    }
-
-    #[test]
-    fn preferred_receive_wall_accepts_kernel_timestamp_exactly_at_the_lag_bound() {
-        // The bound is inclusive: a lag of exactly MAX_KERNEL_RX_LAG is
-        // still accepted, one nanosecond more is not.
-        let userspace = userspace_wall();
-        let at_bound = userspace - MAX_KERNEL_RX_LAG;
-        let past_bound = userspace - MAX_KERNEL_RX_LAG - Duration::from_nanos(1);
-
-        assert_eq!(
-            meta_with_kernel_rx(at_bound).preferred_receive_wall(userspace),
-            at_bound
-        );
-        assert_eq!(
-            meta_with_kernel_rx(past_bound).preferred_receive_wall(userspace),
-            userspace
-        );
-    }
-
-    #[test]
-    fn preferred_receive_wall_rejects_implausibly_old_kernel_timestamp() {
-        let userspace = userspace_wall();
-        let kernel = SystemTime::UNIX_EPOCH;
-
-        assert_eq!(
-            meta_with_kernel_rx(kernel).preferred_receive_wall(userspace),
-            userspace
-        );
-    }
-
-    #[test]
-    fn preferred_receive_wall_handles_extreme_timestamps_without_panicking() {
-        let userspace = userspace_wall();
-        let far_future = SystemTime::UNIX_EPOCH + Duration::from_secs(u64::from(u32::MAX)) * 4;
-        let before_epoch = SystemTime::UNIX_EPOCH - Duration::from_secs(u64::from(u32::MAX));
-
-        assert_eq!(
-            meta_with_kernel_rx(far_future).preferred_receive_wall(userspace),
-            userspace
-        );
-        assert_eq!(
-            meta_with_kernel_rx(before_epoch).preferred_receive_wall(userspace),
-            userspace
-        );
-        assert_eq!(
-            ReceiveMeta::default().preferred_receive_wall(before_epoch),
-            before_epoch
-        );
-    }
-
-    #[test]
-    fn metadata_preserves_kernel_timestamp_rejected_for_measurement() {
-        let userspace = userspace_wall();
-        let rejected = userspace + Duration::from_secs(30);
-        let meta = meta_with_kernel_rx(rejected);
-
-        assert_eq!(meta.preferred_receive_wall(userspace), userspace);
-        assert_eq!(
-            PacketMeta::from(meta).kernel_rx_timestamp,
-            Some(rejected),
-            "observed metadata must survive rejection as a measurement endpoint"
-        );
-    }
-
-    #[test]
-    fn metadata_observed_traffic_class_zero_preserves_observed_zero() {
-        let packet_meta = PacketMeta::from(ReceiveMeta {
-            traffic_class: Some(0),
-            kernel_rx_timestamp: None,
-        });
-
-        assert_eq!(packet_meta.traffic_class, Some(0));
-        assert_eq!(packet_meta.dscp, Some(0));
-        assert_eq!(packet_meta.ecn, Some(0));
-        assert_eq!(packet_meta.kernel_rx_timestamp, None);
-    }
-
-    #[test]
-    fn metadata_observed_traffic_class_derives_dscp_and_ecn() {
-        let packet_meta = PacketMeta::from(ReceiveMeta {
-            traffic_class: Some(184),
-            kernel_rx_timestamp: None,
-        });
-
-        assert_eq!(packet_meta.traffic_class, Some(184));
-        assert_eq!(packet_meta.dscp, Some(46));
-        assert_eq!(packet_meta.ecn, Some(0));
-        assert_eq!(packet_meta.kernel_rx_timestamp, None);
-
-        let packet_meta = PacketMeta::from(ReceiveMeta {
-            traffic_class: Some(186),
-            kernel_rx_timestamp: None,
-        });
-
-        assert_eq!(packet_meta.traffic_class, Some(186));
-        assert_eq!(packet_meta.dscp, Some(46));
-        assert_eq!(packet_meta.ecn, Some(2));
-        assert_eq!(packet_meta.kernel_rx_timestamp, None);
-    }
-
-    #[test]
-    fn metadata_mapping_preserves_none_vs_observed_zero() {
-        let unavailable = PacketMeta::from(ReceiveMeta::default());
-        let observed_zero = PacketMeta::from(ReceiveMeta {
-            traffic_class: Some(0),
-            kernel_rx_timestamp: None,
-        });
-
-        assert_eq!(unavailable.traffic_class, None);
-        assert_eq!(unavailable.dscp, None);
-        assert_eq!(unavailable.ecn, None);
-
-        assert_eq!(observed_zero.traffic_class, Some(0));
-        assert_eq!(observed_zero.dscp, Some(0));
-        assert_eq!(observed_zero.ecn, Some(0));
-    }
-}

crates/irtt-client/src/probe.rs

@@ -1,5 +1,5 @@
 use std::{
-    collections::{HashMap, HashSet, TryReserveError, VecDeque},
+    collections::{HashMap, HashSet, VecDeque},
     time::{Instant, SystemTime},
 };
 
@@ -39,7 +39,8 @@ pub(crate) struct PendingProbe {
     /// eligible only for upstream one-way delay after local plausibility
     /// validation against `tx_not_before_wall` (see `compute_one_way`'s
     /// `preferred_send_wall`). `sent_at` remains the userspace fallback for
-    /// upstream one-way delay when this is absent or implausible.
+    /// upstream one-way delay when this is absent, implausible, or kernel-ID
+    /// correlation was invalidated by a failed probe submission.
     pub kernel_tx_timestamp: Option<SystemTime>,
 }
 
@@ -84,7 +85,12 @@ impl PendingMap {
             });
         }
         if self.map.len() == self.map.capacity() {
-            self.map.try_reserve(1).map_err(pending_allocation_failed)?;
+            self.map
+                .try_reserve(1)
+                .map_err(|source| ClientError::AllocationFailed {
+                    operation: "pending probe storage",
+                    source,
+                })?;
         }
         Ok(())
     }
@@ -185,8 +191,8 @@ impl PendingMap {
         ExpiredBatch { probes, more_due }
     }
 
-    pub fn len(&self) -> usize {
-        self.map.len()
+    pub fn is_empty(&self) -> bool {
+        self.map.is_empty()
     }
 
     /// Mutable access to a still-pending probe by wire sequence, without
@@ -197,14 +203,13 @@ impl PendingMap {
         self.map.get_mut(&wire_seq).map(|entry| &mut entry.probe)
     }
 
-    #[cfg(any(feature = "tokio", test))]
     pub fn next_timeout_deadline(&self) -> Option<Instant> {
         self.first
             .and_then(|wire_seq| self.map.get(&wire_seq))
             .map(|entry| entry.probe.timeout_at)
     }
 
-    #[cfg(any(feature = "tokio", test))]
+    #[cfg(feature = "tokio")]
     pub fn latest_timeout_deadline(&self) -> Option<Instant> {
         self.last
             .and_then(|wire_seq| self.map.get(&wire_seq))
@@ -233,35 +238,6 @@ impl PendingMap {
             );
         }
     }
-
-    #[cfg(test)]
-    pub fn contains(&self, wire_seq: u32) -> bool {
-        self.map.contains_key(&wire_seq)
-    }
-
-    #[cfg(test)]
-    pub fn capacity(&self) -> usize {
-        self.map.capacity()
-    }
-
-    #[cfg(test)]
-    pub fn linkage(&self) -> (Option<u32>, Option<u32>) {
-        (self.first, self.last)
-    }
-
-    #[cfg(test)]
-    pub fn entry_links(&self, wire_seq: u32) -> Option<(Option<u32>, Option<u32>)> {
-        self.map
-            .get(&wire_seq)
-            .map(|entry| (entry.previous, entry.next))
-    }
-}
-
-fn pending_allocation_failed(source: TryReserveError) -> ClientError {
-    ClientError::AllocationFailed {
-        operation: "pending probe storage",
-        source,
-    }
 }
 
 #[derive(Debug)]
@@ -312,31 +288,11 @@ impl TimedOutMap {
         self.map.get_mut(&wire_seq)
     }
 
-    pub fn clear(&mut self) {
-        self.map.clear();
-        self.insertion_order.clear();
-    }
-
-    #[cfg(test)]
-    pub fn len(&self) -> usize {
-        self.map.len()
-    }
-
     #[cfg(feature = "tokio")]
     pub fn latest_timeout_deadline(&self) -> Option<Instant> {
         self.map.values().map(|probe| probe.timeout_at).max()
     }
 
-    #[cfg(test)]
-    pub fn contains(&self, wire_seq: u32) -> bool {
-        self.map.contains_key(&wire_seq)
-    }
-
-    #[cfg(test)]
-    fn insertion_order_len(&self) -> usize {
-        self.insertion_order.len()
-    }
-
     fn evict_oldest(&mut self) {
         while let Some(oldest_key) = self.insertion_order.pop_front() {
             if self.map.remove(&oldest_key).is_some() {
@@ -419,263 +375,69 @@ mod tests {
         }
     }
 
-    fn insert(map: &mut PendingMap, probe: PendingProbe) {
-        map.preflight_insert(probe.wire_seq).unwrap();
-        map.commit_insert(probe);
-    }
-
     #[test]
-    fn pending_map_rejects_over_capacity() {
-        let mut map = PendingMap::new(2);
-        let now = Instant::now();
-        map.preflight_insert(0).unwrap();
-        map.commit_insert(pending(0, now + Duration::from_secs(4)));
-        map.preflight_insert(1).unwrap();
-        map.commit_insert(pending(1, now + Duration::from_secs(4)));
-        assert!(matches!(
-            map.preflight_insert(2),
-            Err(ClientError::PendingLimitExceeded { limit: 2 })
-        ));
-    }
-
-    #[test]
-    fn pending_map_preflight_reserves_without_changing_contents() {
-        let mut map = PendingMap::new(2);
-        let initial_capacity = map.capacity();
-
-        map.preflight_insert(7).unwrap();
-        let reserved_capacity = map.capacity();
-        assert!(reserved_capacity >= initial_capacity);
-        assert_eq!(map.len(), 0);
-        assert!(!map.contains(7));
-
-        map.preflight_insert(7).unwrap();
-        assert_eq!(map.capacity(), reserved_capacity);
-        assert_eq!(map.len(), 0);
-        assert!(!map.contains(7));
-    }
-
-    #[test]
-    fn pending_map_preflight_rejects_sequence_collision() {
-        let mut map = PendingMap::new(2);
-        let now = Instant::now();
-        map.preflight_insert(9).unwrap();
-        map.commit_insert(pending(9, now));
-
-        assert!(matches!(
-            map.preflight_insert(9),
-            Err(ClientError::PendingSequenceCollision { seq: 9 })
-        ));
-        assert_eq!(map.len(), 1);
-    }
-
-    #[test]
-    fn pending_map_allocation_failure_maps_to_dedicated_error() {
-        let mut map = HashMap::<u32, PendingProbe>::new();
-        let source = map.try_reserve(usize::MAX).unwrap_err();
-
-        assert!(matches!(
-            pending_allocation_failed(source),
-            ClientError::AllocationFailed {
-                operation: "pending probe storage",
-                ..
+    fn pending_removal_and_sequence_reuse_preserve_expiry_and_capacity() {
+        let start = Instant::now();
+        // Remove the head, middle or tail, then reuse that sequence at a later
+        // deadline. Observe expiry and capacity, not private list links.
+        for removed in 0..3 {
+            let mut pending_map = PendingMap::new(3);
+            for seq in 0..3 {
+                pending_map.preflight_insert(seq).unwrap();
+                pending_map
+                    .commit_insert(pending(seq, start + Duration::from_secs(u64::from(seq))));
             }
-        ));
-    }
+            assert!(matches!(
+                pending_map.preflight_insert(3),
+                Err(ClientError::PendingLimitExceeded { .. })
+            ));
+            assert_eq!(pending_map.remove(removed).unwrap().wire_seq, removed);
+            pending_map.preflight_insert(removed).unwrap();
+            let reused_deadline = start + Duration::from_secs(4);
+            pending_map.commit_insert(pending(removed, reused_deadline));
 
-    #[test]
-    fn pending_map_unlinks_head_middle_and_tail_and_updates_extrema() {
-        let mut map = PendingMap::new(4);
-        let now = Instant::now();
-        insert(&mut map, pending(1, now + Duration::from_secs(1)));
-        insert(&mut map, pending(2, now + Duration::from_secs(2)));
-        insert(&mut map, pending(3, now + Duration::from_secs(3)));
-
-        assert_eq!(
-            map.next_timeout_deadline(),
-            Some(now + Duration::from_secs(1))
-        );
-        assert_eq!(
-            map.latest_timeout_deadline(),
-            Some(now + Duration::from_secs(3))
-        );
-        assert_eq!(map.linkage(), (Some(1), Some(3)));
-        assert_eq!(map.entry_links(1), Some((None, Some(2))));
-        assert_eq!(map.entry_links(2), Some((Some(1), Some(3))));
-        assert_eq!(map.entry_links(3), Some((Some(2), None)));
-
-        assert!(map.remove(2).is_some());
-        assert_eq!(
-            map.next_timeout_deadline(),
-            Some(now + Duration::from_secs(1))
-        );
-        assert_eq!(
-            map.latest_timeout_deadline(),
-            Some(now + Duration::from_secs(3))
-        );
-        assert_eq!(map.linkage(), (Some(1), Some(3)));
-        assert_eq!(map.entry_links(1), Some((None, Some(3))));
-        assert_eq!(map.entry_links(3), Some((Some(1), None)));
-
-        assert!(map.remove(1).is_some());
-        assert_eq!(
-            map.next_timeout_deadline(),
-            Some(now + Duration::from_secs(3))
-        );
-        assert_eq!(
-            map.latest_timeout_deadline(),
-            Some(now + Duration::from_secs(3))
-        );
-        assert_eq!(map.linkage(), (Some(3), Some(3)));
-        assert_eq!(map.entry_links(3), Some((None, None)));
-
-        assert!(map.remove(3).is_some());
-        assert_eq!(map.next_timeout_deadline(), None);
-        assert_eq!(map.latest_timeout_deadline(), None);
-        assert_eq!(map.linkage(), (None, None));
-    }
-
-    #[test]
-    fn pending_map_bounded_expiration_matches_exhaustive_order() {
-        let now = Instant::now();
-        let probes = [
-            pending(1, now + Duration::from_secs(1)),
-            pending(2, now + Duration::from_secs(2)),
-            pending(3, now + Duration::from_secs(3)),
-            pending(4, now + Duration::from_secs(4)),
-        ];
-        let mut bounded = PendingMap::new(probes.len());
-        let mut exhaustive = PendingMap::new(probes.len());
-        for probe in probes.iter().cloned() {
-            insert(&mut bounded, probe.clone());
-            insert(&mut exhaustive, probe);
-        }
-
-        let empty = bounded.drain_expired_bounded(now + Duration::from_secs(4), 0);
-        assert!(empty.probes.is_empty());
-        assert!(empty.more_due);
-        assert_eq!(bounded.linkage(), (Some(1), Some(4)));
-
-        let mut actual = Vec::new();
-        loop {
-            let batch = bounded.drain_expired_bounded(now + Duration::from_secs(4), 2);
-            actual.extend(batch.probes.into_iter().map(|probe| probe.wire_seq));
-            if !batch.more_due {
-                break;
+            let remaining = (0..3).filter(|seq| *seq != removed).collect::<Vec<_>>();
+            for (index, seq) in remaining.iter().enumerate() {
+                assert_eq!(
+                    pending_map.next_timeout_deadline(),
+                    Some(start + Duration::from_secs(u64::from(*seq)))
+                );
+                let expired = pending_map.drain_expired_bounded(start + Duration::from_secs(3), 1);
+                assert_eq!(
+                    expired
+                        .probes
+                        .iter()
+                        .map(|probe| probe.wire_seq)
+                        .collect::<Vec<_>>(),
+                    vec![*seq]
+                );
+                assert_eq!(expired.more_due, index == 0);
             }
+            assert_eq!(pending_map.next_timeout_deadline(), Some(reused_deadline));
+            let expired = pending_map.drain_expired_bounded(reused_deadline, 3);
+            assert_eq!(expired.probes.len(), 1);
+            assert_eq!(expired.probes[0].wire_seq, removed);
+            assert!(!expired.more_due);
+            assert!(pending_map.is_empty());
+            assert_eq!(pending_map.next_timeout_deadline(), None);
+            pending_map.preflight_insert(removed).unwrap();
+            pending_map.commit_insert(pending(removed, reused_deadline));
+            assert_eq!(pending_map.remove(removed).unwrap().wire_seq, removed);
+            assert!(pending_map.is_empty());
         }
-        let expected = exhaustive
-            .drain_expired_bounded(now + Duration::from_secs(4), usize::MAX)
-            .probes
-            .into_iter()
-            .map(|probe| probe.wire_seq)
-            .collect::<Vec<_>>();
-
-        assert_eq!(actual, expected);
-        assert_eq!(actual, vec![1, 2, 3, 4]);
-        assert_eq!(bounded.linkage(), (None, None));
     }
 
+    // Public loss/reply events cannot reveal leaked retention bookkeeping.
     #[test]
-    fn pending_map_sequence_reuse_leaves_no_stale_link() {
-        let mut map = PendingMap::new(1);
-        let now = Instant::now();
-        insert(&mut map, pending(7, now));
-        assert!(map.remove(7).is_some());
-        insert(&mut map, pending(7, now + Duration::from_secs(1)));
-
-        assert!(map.drain_expired_bounded(now, usize::MAX).probes.is_empty());
-        assert_eq!(map.linkage(), (Some(7), Some(7)));
-        assert_eq!(map.entry_links(7), Some((None, None)));
-        assert_eq!(
-            map.drain_expired_bounded(now + Duration::from_secs(1), usize::MAX)
-                .probes
-                .into_iter()
-                .map(|probe| probe.wire_seq)
-                .collect::<Vec<_>>(),
-            vec![7]
-        );
-        assert_eq!(map.linkage(), (None, None));
-    }
-
-    #[test]
-    fn pending_map_commit_uses_only_preflighted_map_capacity() {
-        let mut map = PendingMap::new(2);
-        let now = Instant::now();
-        map.preflight_insert(7).unwrap();
-        let capacity = map.capacity();
-
-        map.commit_insert(pending(7, now));
-
-        assert_eq!(map.capacity(), capacity);
-        assert_eq!(map.len(), 1);
-        assert_eq!(map.linkage(), (Some(7), Some(7)));
-    }
-
-    #[test]
-    fn pending_map_mixed_removals_preserve_links() {
-        let mut map = PendingMap::new(4);
-        let now = Instant::now();
-        for seq in 1..=4 {
-            insert(
-                &mut map,
-                pending(seq, now + Duration::from_secs(u64::from(seq))),
-            );
-        }
-
-        assert!(map.remove(2).is_some());
-        assert_eq!(map.entry_links(1), Some((None, Some(3))));
-        assert_eq!(map.entry_links(3), Some((Some(1), Some(4))));
-        let expired = map.drain_expired_bounded(now + Duration::from_secs(3), usize::MAX);
-        assert_eq!(
-            expired
-                .probes
-                .into_iter()
-                .map(|probe| probe.wire_seq)
-                .collect::<Vec<_>>(),
-            vec![1, 3]
-        );
-        assert_eq!(map.linkage(), (Some(4), Some(4)));
-        assert!(map.remove(4).is_some());
-        assert_eq!(map.linkage(), (None, None));
-    }
-
-    #[test]
-    fn bounded_probe_tracking_evicts_oldest_entries() {
-        let mut set = CompletedSet::new(3);
-        set.insert(0);
-        set.insert(1);
-        set.insert(2);
-        assert!(set.contains(0));
-        assert!(set.contains(1));
-        assert!(set.contains(2));
-        set.insert(3);
-        assert_eq!(set.set.len(), 3);
-        assert!(!set.contains(0));
-        assert!(set.contains(3));
-
-        let mut map = TimedOutMap::new(2);
-        let now = Instant::now();
-        map.insert(pending(0, now));
-        map.insert(pending(1, now));
-        map.insert(pending(2, now));
-
-        assert_eq!(map.len(), 2);
-        assert!(map.remove(0).is_none());
-        assert!(map.remove(1).is_some());
-        assert!(map.remove(2).is_some());
-    }
-
-    #[test]
-    fn timed_out_map_remove_prunes_insertion_order() {
+    fn timed_out_retention_stays_bounded_after_repeated_removals() {
         let mut map = TimedOutMap::new(4);
         let now = Instant::now();
 
         for i in 0..20 {
             map.insert(pending(i, now));
             assert!(map.remove(i).is_some());
-            assert_eq!(map.len(), 0);
-            assert_eq!(map.insertion_order_len(), 0);
+            assert!(map.map.len() <= 4);
+            assert!(map.insertion_order.len() <= 4);
         }
     }
 }

crates/irtt-client/src/receive.rs

@@ -111,80 +111,3 @@ pub(crate) fn drain_tx_timestamps<S: std::os::fd::AsRawFd>(
 ) -> io::Result<()> {
     linux::drain_tx_timestamps(socket, on_timestamp)
 }
-
-#[cfg(test)]
-mod tests {
-    use std::net::UdpSocket;
-
-    use crate::{metadata::ReceiveMeta, receive::recv_datagram, timing::ClientTimestamp};
-
-    fn connected_loopback_pair() -> (UdpSocket, UdpSocket) {
-        let a = UdpSocket::bind("127.0.0.1:0").unwrap();
-        let b = UdpSocket::bind("127.0.0.1:0").unwrap();
-        a.connect(b.local_addr().unwrap()).unwrap();
-        b.connect(a.local_addr().unwrap()).unwrap();
-        (a, b)
-    }
-
-    #[test]
-    fn fallback_receive_returns_length() {
-        let (sender, receiver) = connected_loopback_pair();
-        sender.send(b"hello").unwrap();
-
-        let mut buf = [0_u8; 16];
-        let datagram = recv_datagram(&receiver, &mut buf).unwrap();
-
-        assert_eq!(datagram.len, 5);
-        assert_eq!(&buf[..datagram.len], b"hello");
-    }
-
-    #[test]
-    fn fallback_receive_returns_default_metadata() {
-        let (sender, receiver) = connected_loopback_pair();
-        sender.send(b"meta").unwrap();
-
-        let mut buf = [0_u8; 16];
-        let datagram = recv_datagram(&receiver, &mut buf).unwrap();
-
-        assert_eq!(datagram.meta, ReceiveMeta::default());
-    }
-
-    #[test]
-    fn fallback_receive_captures_timestamp_after_successful_receive() {
-        let (sender, receiver) = connected_loopback_pair();
-        sender.send(b"time").unwrap();
-
-        let before = ClientTimestamp::now();
-        let mut buf = [0_u8; 16];
-        let datagram = recv_datagram(&receiver, &mut buf).unwrap();
-        let after = ClientTimestamp::now();
-
-        assert!(datagram.received_at.mono >= before.mono);
-        assert!(datagram.received_at.mono <= after.mono);
-    }
-
-    #[cfg(feature = "tokio")]
-    #[test]
-    fn tokio_try_receive_preserves_fallback_metadata_and_would_block() {
-        let runtime = tokio::runtime::Builder::new_current_thread()
-            .enable_io()
-            .build()
-            .unwrap();
-
-        runtime.block_on(async {
-            let (sender, receiver) = connected_loopback_pair();
-            receiver.set_nonblocking(true).unwrap();
-            let receiver = tokio::net::UdpSocket::from_std(receiver).unwrap();
-            sender.send(b"tokio").unwrap();
-            receiver.readable().await.unwrap();
-
-            let mut buf = [0_u8; 16];
-            let datagram = super::try_recv_tokio_datagram(&receiver, &mut buf).unwrap();
-            assert_eq!(&buf[..datagram.len], b"tokio");
-            assert_eq!(datagram.meta, ReceiveMeta::default());
-
-            let error = super::try_recv_tokio_datagram(&receiver, &mut buf).unwrap_err();
-            assert_eq!(error.kind(), std::io::ErrorKind::WouldBlock);
-        });
-    }
-}

crates/irtt-client/src/receive/linux.rs

@@ -12,14 +12,17 @@
 //! After a successful Open, the client adapter best-effort upgrades the
 //! socket from [`RX_TIMESTAMPING_FLAGS`] to [`error_queue::TX_TIMESTAMPING_FLAGS`]
 //! via [`try_enable_tx_timestamping`]. When that succeeds, the automatic
-//! `SOF_TIMESTAMPING_OPT_ID` counter the kernel assigns to each successfully
-//! submitted datagram is used directly as the probe's wire sequence number
-//! (see the client crate's `AGENTS.md` for the correlation invariant this
-//! relies on). [`drain_tx_timestamps`] performs a small bounded, nonblocking
-//! read of `MSG_ERRQUEUE` so the adapter can opportunistically collect those
-//! timestamps without ever waiting for one. The observed kernel TX wall time
-//! is retained as metadata only; it is not consumed by any measurement in
-//! this change.
+//! `SOF_TIMESTAMPING_OPT_ID` counter normally tracks the probe wire sequence
+//! after successful sends, so it is used as a best-effort correlation ID.
+//! A kernel ID can theoretically be consumed by a send that later fails,
+//! desynchronizing that correlation. [`drain_tx_timestamps`] discards
+//! unmatched or implausible records; the userspace `sent_at` timestamp remains
+//! the fallback. After a probe send failure, correlation is disabled for that
+//! session so later IDs cannot be misattributed. It performs a small bounded,
+//! nonblocking read of
+//! `MSG_ERRQUEUE` so the adapter can opportunistically collect timestamps
+//! without ever waiting for one. A plausible kernel TX wall time is used only
+//! for upstream one-way delay; RTT retains the userspace send instant.
 
 use std::{
     io::{self, IoSliceMut},
@@ -158,12 +161,12 @@ fn recv_datagram_fd(
     buf: &mut [u8],
     flags: MsgFlags,
 ) -> Result<ReceivedDatagram, io::Error> {
-    let mut control = ControlBuffer::new();
+    let mut control = ControlBuffer([0; CONTROL_LEN]);
     let mut iov = [IoSliceMut::new(buf)];
 
     // The socket is connected, so the source address is not needed; `()` skips
     // copying it out.
-    let msg = recvmsg::<()>(socket_fd, &mut iov, Some(control.as_mut_slice()), flags)?;
+    let msg = recvmsg::<()>(socket_fd, &mut iov, Some(&mut control.0), flags)?;
     let received_at = ClientTimestamp::now();
 
     Ok(ReceivedDatagram {
@@ -212,343 +215,3 @@ fn system_time_from_timespec(timespec: TimeSpec) -> Option<SystemTime> {
 /// `cmsghdr` alignment, which 8-byte alignment covers on supported targets.
 #[repr(align(8))]
 struct ControlBuffer([u8; CONTROL_LEN]);
-
-impl ControlBuffer {
-    fn new() -> Self {
-        Self([0; CONTROL_LEN])
-    }
-
-    fn as_mut_slice(&mut self) -> &mut [u8] {
-        &mut self.0
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use std::{
-        io,
-        net::{SocketAddr, UdpSocket},
-        time::{Duration, UNIX_EPOCH},
-    };
-
-    use nix::sys::time::TimeSpec;
-
-    use crate::{
-        event::PacketMeta,
-        receive::{configure_receive_metadata, recv_datagram},
-        socket_options::apply_traffic_class_to_socket,
-        timing::ClientTimestamp,
-    };
-
-    fn connected_ipv4_loopback_pair() -> (UdpSocket, UdpSocket) {
-        let a = UdpSocket::bind(SocketAddr::from(([127, 0, 0, 1], 0))).unwrap();
-        let b = UdpSocket::bind(SocketAddr::from(([127, 0, 0, 1], 0))).unwrap();
-        a.connect(b.local_addr().unwrap()).unwrap();
-        b.connect(a.local_addr().unwrap()).unwrap();
-        a.set_read_timeout(Some(Duration::from_millis(200)))
-            .unwrap();
-        b.set_read_timeout(Some(Duration::from_millis(200)))
-            .unwrap();
-        (a, b)
-    }
-
-    fn connected_ipv6_loopback_pair() -> Option<(UdpSocket, UdpSocket)> {
-        let bind_addr = SocketAddr::from(([0, 0, 0, 0, 0, 0, 0, 1], 0));
-        let a = match UdpSocket::bind(bind_addr) {
-            Ok(socket) => socket,
-            Err(error) if is_unavailable_ipv6_loopback(&error) => {
-                eprintln!(
-                    "skipping IPv6 ancillary receive test: IPv6 loopback unavailable: {error}"
-                );
-                return None;
-            }
-            Err(error) => panic!("{error}"),
-        };
-        let b = match UdpSocket::bind(bind_addr) {
-            Ok(socket) => socket,
-            Err(error) if is_unavailable_ipv6_loopback(&error) => {
-                eprintln!(
-                    "skipping IPv6 ancillary receive test: IPv6 loopback unavailable: {error}"
-                );
-                return None;
-            }
-            Err(error) => panic!("{error}"),
-        };
-        match a.connect(b.local_addr().unwrap()) {
-            Ok(()) => {}
-            Err(error) if is_unavailable_ipv6_loopback(&error) => {
-                eprintln!(
-                    "skipping IPv6 ancillary receive test: IPv6 loopback unavailable: {error}"
-                );
-                return None;
-            }
-            Err(error) => panic!("{error}"),
-        }
-        match b.connect(a.local_addr().unwrap()) {
-            Ok(()) => {}
-            Err(error) if is_unavailable_ipv6_loopback(&error) => {
-                eprintln!(
-                    "skipping IPv6 ancillary receive test: IPv6 loopback unavailable: {error}"
-                );
-                return None;
-            }
-            Err(error) => panic!("{error}"),
-        }
-        a.set_read_timeout(Some(Duration::from_millis(200)))
-            .unwrap();
-        b.set_read_timeout(Some(Duration::from_millis(200)))
-            .unwrap();
-        Some((a, b))
-    }
-
-    #[test]
-    fn recvmsg_receive_returns_length_payload_and_timestamp() {
-        let (sender, receiver) = connected_ipv4_loopback_pair();
-        configure_receive_metadata(&receiver, sender.local_addr().unwrap()).unwrap();
-        sender.send(b"hello").unwrap();
-
-        let before = ClientTimestamp::now();
-        let mut buf = [0_u8; 16];
-        let datagram = recv_datagram(&receiver, &mut buf).unwrap();
-        let after = ClientTimestamp::now();
-
-        assert_eq!(datagram.len, 5);
-        assert_eq!(&buf[..datagram.len], b"hello");
-        assert!(datagram.received_at.mono >= before.mono);
-        assert!(datagram.received_at.mono <= after.mono);
-    }
-
-    #[cfg(feature = "tokio")]
-    #[test]
-    fn tokio_recvmsg_would_block_clears_readiness() {
-        let runtime = tokio::runtime::Builder::new_current_thread()
-            .enable_io()
-            .enable_time()
-            .build()
-            .unwrap();
-
-        runtime.block_on(async {
-            let (sender, receiver) = connected_ipv4_loopback_pair();
-            configure_receive_metadata(&receiver, sender.local_addr().unwrap()).unwrap();
-            receiver.set_nonblocking(true).unwrap();
-            let receiver = tokio::net::UdpSocket::from_std(receiver).unwrap();
-            let mut buf = [0_u8; 16];
-
-            sender.send(b"first").unwrap();
-            tokio::time::timeout(Duration::from_secs(1), receiver.readable())
-                .await
-                .expect("initial readability timed out")
-                .unwrap();
-
-            let first = super::try_recv_tokio_datagram(&receiver, &mut buf).unwrap();
-            assert_eq!(&buf[..first.len], b"first");
-
-            let error = super::try_recv_tokio_datagram(&receiver, &mut buf).unwrap_err();
-            assert_eq!(error.kind(), io::ErrorKind::WouldBlock);
-
-            assert!(
-                tokio::time::timeout(Duration::from_millis(20), receiver.readable())
-                    .await
-                    .is_err(),
-                "readable completed from stale readiness after recvmsg WouldBlock"
-            );
-
-            sender.send(b"second").unwrap();
-            tokio::time::timeout(Duration::from_secs(1), receiver.readable())
-                .await
-                .expect("second readability timed out")
-                .unwrap();
-
-            let second = super::try_recv_tokio_datagram(&receiver, &mut buf).unwrap();
-            assert_eq!(&buf[..second.len], b"second");
-        });
-    }
-
-    #[test]
-    fn kernel_rx_timestamp_metadata_is_observed_when_kernel_provides_it() {
-        let (sender, receiver) = connected_ipv4_loopback_pair();
-        configure_receive_metadata(&receiver, sender.local_addr().unwrap()).unwrap();
-        sender.send(b"stamp").unwrap();
-
-        let mut buf = [0_u8; 16];
-        let datagram = recv_datagram(&receiver, &mut buf).unwrap();
-        assert_eq!(datagram.len, 5);
-        assert_eq!(&buf[..datagram.len], b"stamp");
-        let Some(timestamp) = datagram.meta.kernel_rx_timestamp else {
-            eprintln!(
-                "skipping kernel timestamp assertion: kernel did not provide SCM_TIMESTAMPING"
-            );
-            return;
-        };
-
-        let duration = timestamp.duration_since(UNIX_EPOCH).unwrap();
-        assert!(duration.as_nanos() > 0);
-    }
-
-    #[test]
-    fn kernel_rx_timestamp_and_traffic_class_coexist() {
-        let (sender, receiver) = connected_ipv4_loopback_pair();
-        configure_receive_metadata(&receiver, sender.local_addr().unwrap()).unwrap();
-        apply_traffic_class_to_socket(&sender, receiver.local_addr().unwrap(), 184).unwrap();
-        sender.send(b"both").unwrap();
-
-        let mut buf = [0_u8; 16];
-        let datagram = recv_datagram(&receiver, &mut buf).unwrap();
-        assert_eq!(&buf[..datagram.len], b"both");
-
-        // Both cmsgs are requested on this socket; the parser must not
-        // depend on the order the kernel emits them in to observe either.
-        if datagram.meta.kernel_rx_timestamp.is_none() {
-            eprintln!("skipping combined assertion: kernel did not provide SCM_TIMESTAMPING");
-            return;
-        }
-        if datagram.meta.traffic_class.is_none() {
-            eprintln!("skipping combined assertion: kernel did not provide IP_TOS");
-            return;
-        }
-        assert!(datagram.meta.kernel_rx_timestamp.is_some());
-        assert_eq!(datagram.meta.traffic_class.unwrap() & 0xfc, 184);
-    }
-
-    #[test]
-    fn ipv4_traffic_class_metadata_is_observed_when_kernel_provides_it() {
-        let (sender, receiver) = connected_ipv4_loopback_pair();
-        configure_receive_metadata(&receiver, sender.local_addr().unwrap()).unwrap();
-        apply_traffic_class_to_socket(&sender, receiver.local_addr().unwrap(), 184).unwrap();
-        sender.send(b"dscp").unwrap();
-
-        let mut buf = [0_u8; 16];
-        let datagram = recv_datagram(&receiver, &mut buf).unwrap();
-        let Some(traffic_class) = datagram.meta.traffic_class else {
-            eprintln!("skipping IPv4 ancillary metadata assertion: kernel did not provide IP_TOS");
-            return;
-        };
-
-        let packet_meta = PacketMeta::from(datagram.meta);
-        assert_eq!(traffic_class & 0xfc, 184);
-        assert_eq!(packet_meta.dscp, Some(46));
-        assert_eq!(packet_meta.ecn, Some(0));
-    }
-
-    #[test]
-    fn ipv6_traffic_class_metadata_is_observed_when_kernel_provides_it() {
-        let Some((sender, receiver)) = connected_ipv6_loopback_pair() else {
-            return;
-        };
-        configure_receive_metadata(&receiver, sender.local_addr().unwrap()).unwrap();
-        apply_traffic_class_to_socket(&sender, receiver.local_addr().unwrap(), 184).unwrap();
-        sender.send(b"dscp").unwrap();
-
-        let mut buf = [0_u8; 16];
-        let datagram = recv_datagram(&receiver, &mut buf).unwrap();
-        let Some(traffic_class) = datagram.meta.traffic_class else {
-            eprintln!(
-                "skipping IPv6 ancillary metadata assertion: kernel did not provide IPV6_TCLASS"
-            );
-            return;
-        };
-
-        let packet_meta = PacketMeta::from(datagram.meta);
-        assert_eq!(traffic_class & 0xfc, 184);
-        assert_eq!(packet_meta.dscp, Some(46));
-        assert_eq!(packet_meta.ecn, Some(0));
-    }
-
-    #[test]
-    fn observed_zero_traffic_class_preserves_some_zero() {
-        let (sender, receiver) = connected_ipv4_loopback_pair();
-        configure_receive_metadata(&receiver, sender.local_addr().unwrap()).unwrap();
-        sender.send(b"zero").unwrap();
-
-        let mut buf = [0_u8; 16];
-        let datagram = recv_datagram(&receiver, &mut buf).unwrap();
-        let Some(traffic_class) = datagram.meta.traffic_class else {
-            eprintln!("skipping observed-zero assertion: kernel did not provide IP_TOS");
-            return;
-        };
-
-        let packet_meta = PacketMeta::from(datagram.meta);
-        assert_eq!(traffic_class, 0);
-        assert_eq!(packet_meta.traffic_class, Some(0));
-        assert_eq!(packet_meta.dscp, Some(0));
-        assert_eq!(packet_meta.ecn, Some(0));
-    }
-
-    #[test]
-    fn timespec_conversion_accepts_valid_unix_timestamp() {
-        let timestamp = super::system_time_from_timespec(TimeSpec::new(1, 2)).unwrap();
-
-        assert_eq!(
-            timestamp.duration_since(UNIX_EPOCH).unwrap(),
-            Duration::new(1, 2)
-        );
-    }
-
-    #[test]
-    fn timespec_conversion_rejects_negative_or_invalid_values() {
-        assert_eq!(super::system_time_from_timespec(TimeSpec::new(-1, 0)), None);
-        assert_eq!(super::system_time_from_timespec(TimeSpec::new(0, -1)), None);
-        assert_eq!(
-            super::system_time_from_timespec(TimeSpec::new(0, 1_000_000_000)),
-            None
-        );
-    }
-
-    fn is_unavailable_ipv6_loopback(error: &io::Error) -> bool {
-        matches!(
-            error.kind(),
-            io::ErrorKind::AddrNotAvailable | io::ErrorKind::Unsupported
-        )
-    }
-
-    #[test]
-    fn try_enable_tx_timestamping_then_drain_reports_ids_through_the_adapter_api() {
-        let (socket, _peer) = connected_ipv4_loopback_pair();
-        // Mirrors production: RX-only first, then a best-effort upgrade.
-        configure_receive_metadata(&socket, socket.peer_addr().unwrap()).unwrap();
-
-        if !super::try_enable_tx_timestamping(&socket) {
-            eprintln!(
-                "skipping adapter-level TX timestamping smoke test: kernel/container denied \
-                 SO_TIMESTAMPING TX flags"
-            );
-            return;
-        }
-
-        if let Err(error) = socket.send(b"one") {
-            eprintln!("skipping adapter-level TX timestamping smoke test: send failed: {error}");
-            return;
-        }
-
-        let deadline = std::time::Instant::now() + Duration::from_secs(2);
-        let mut observed = None;
-        while observed.is_none() && std::time::Instant::now() < deadline {
-            super::drain_tx_timestamps(&socket, |id, timestamp| {
-                observed = Some((id, timestamp));
-            })
-            .unwrap();
-            std::thread::yield_now();
-        }
-
-        let Some((id, timestamp)) = observed else {
-            eprintln!(
-                "skipping adapter-level TX timestamping smoke test: no TX timestamp record \
-                 arrived within the poll deadline"
-            );
-            return;
-        };
-        assert_eq!(id, 0);
-        assert!(timestamp.duration_since(UNIX_EPOCH).unwrap() > Duration::ZERO);
-    }
-
-    #[test]
-    fn drain_tx_timestamps_is_a_bounded_nonblocking_no_op_on_an_untouched_socket() {
-        let (socket, _peer) = connected_ipv4_loopback_pair();
-        configure_receive_metadata(&socket, socket.peer_addr().unwrap()).unwrap();
-
-        let mut calls = 0_usize;
-        super::drain_tx_timestamps(&socket, |_, _| calls += 1).unwrap();
-
-        assert_eq!(calls, 0);
-    }
-}

crates/irtt-client/src/receive/linux/error_queue.rs

@@ -103,10 +103,7 @@ pub(crate) fn classify(cmsgs: impl Iterator<Item = ControlMessageOwned>) -> Erro
 
     for cmsg in cmsgs {
         match cmsg {
-            ControlMessageOwned::Ipv4RecvErr(err, _) => {
-                extended_error = Some((err.ee_errno, err.ee_origin, err.ee_info, err.ee_data));
-            }
-            ControlMessageOwned::Ipv6RecvErr(err, _) => {
+            ControlMessageOwned::Ipv4RecvErr(err, _) | ControlMessageOwned::Ipv6RecvErr(err, _) => {
                 extended_error = Some((err.ee_errno, err.ee_origin, err.ee_info, err.ee_data));
             }
             ControlMessageOwned::ScmTimestampsns(observed) => {
@@ -145,12 +142,6 @@ pub(crate) fn classify(cmsgs: impl Iterator<Item = ControlMessageOwned>) -> Erro
 #[repr(align(8))]
 struct ErrorQueueControlBuffer([u8; ERROR_QUEUE_CONTROL_LEN]);
 
-impl ErrorQueueControlBuffer {
-    fn new() -> Self {
-        Self([0; ERROR_QUEUE_CONTROL_LEN])
-    }
-}
-
 /// Nonblocking drain of a single record from `fd`'s `MSG_ERRQUEUE`.
 ///
 /// Returns `Ok(None)` when the queue is empty (`EAGAIN`/`EWOULDBLOCK`) — the
@@ -171,7 +162,7 @@ impl ErrorQueueControlBuffer {
 pub(crate) fn try_recv_error_queue_record(fd: RawFd) -> io::Result<Option<ErrorQueueRecord>> {
     let mut payload: [u8; 0] = [];
     let mut iov = [IoSliceMut::new(&mut payload)];
-    let mut control = ErrorQueueControlBuffer::new();
+    let mut control = ErrorQueueControlBuffer([0; ERROR_QUEUE_CONTROL_LEN]);
 
     match recvmsg::<()>(
         fd,
@@ -190,456 +181,3 @@ pub(crate) fn try_recv_error_queue_record(fd: RawFd) -> io::Result<Option<ErrorQ
         Err(errno) => Err(io::Error::from(errno)),
     }
 }
-
-#[cfg(test)]
-mod tests {
-    use std::{
-        net::{SocketAddr, UdpSocket},
-        os::fd::AsRawFd,
-        time::{Duration, Instant, UNIX_EPOCH},
-    };
-
-    use nix::sys::{
-        socket::{setsockopt, sockopt},
-        time::TimeSpec,
-    };
-
-    use super::*;
-
-    fn extended_error(
-        errno: u32,
-        origin: u8,
-        info: u32,
-        data: u32,
-    ) -> nix::libc::sock_extended_err {
-        nix::libc::sock_extended_err {
-            ee_errno: errno,
-            ee_origin: origin,
-            ee_type: 0,
-            ee_code: 0,
-            ee_pad: 0,
-            ee_info: info,
-            ee_data: data,
-        }
-    }
-
-    fn timestamps_with_system(system: TimeSpec) -> Timestamps {
-        Timestamps {
-            system,
-            hw_trans: TimeSpec::new(0, 0),
-            hw_raw: TimeSpec::new(0, 0),
-        }
-    }
-
-    fn send_timestamp_error(id: u32) -> ControlMessageOwned {
-        ControlMessageOwned::Ipv4RecvErr(
-            extended_error(
-                nix::libc::ENOMSG as u32,
-                nix::libc::SO_EE_ORIGIN_TIMESTAMPING,
-                SCM_TSTAMP_SND,
-                id,
-            ),
-            None,
-        )
-    }
-
-    #[test]
-    fn classifies_valid_send_timestamp_completion() {
-        let cmsgs = vec![
-            send_timestamp_error(7),
-            ControlMessageOwned::ScmTimestampsns(timestamps_with_system(TimeSpec::new(1, 2))),
-        ];
-
-        let record = classify(cmsgs.into_iter());
-
-        assert_eq!(
-            record,
-            ErrorQueueRecord::TxTimestamp {
-                id: 7,
-                timestamp: UNIX_EPOCH + Duration::new(1, 2),
-            }
-        );
-    }
-
-    #[test]
-    fn classifies_timestamp_origin_without_timestamp_as_malformed() {
-        let cmsgs = vec![send_timestamp_error(3)];
-
-        assert_eq!(
-            classify(cmsgs.into_iter()),
-            ErrorQueueRecord::MalformedOrUnsupportedTimestamp
-        );
-    }
-
-    #[test]
-    fn classifies_timestamp_origin_with_invalid_timespec_as_malformed() {
-        let cmsgs = vec![
-            send_timestamp_error(3),
-            ControlMessageOwned::ScmTimestampsns(timestamps_with_system(TimeSpec::new(-1, 0))),
-        ];
-
-        assert_eq!(
-            classify(cmsgs.into_iter()),
-            ErrorQueueRecord::MalformedOrUnsupportedTimestamp
-        );
-    }
-
-    #[test]
-    fn classifies_non_timestamp_extended_error_as_socket_error() {
-        let cmsgs = vec![ControlMessageOwned::Ipv4RecvErr(
-            extended_error(
-                nix::libc::ECONNREFUSED as u32,
-                nix::libc::SO_EE_ORIGIN_ICMP,
-                0,
-                0,
-            ),
-            None,
-        )];
-
-        assert_eq!(
-            classify(cmsgs.into_iter()),
-            ErrorQueueRecord::SocketError {
-                errno: nix::libc::ECONNREFUSED,
-                origin: nix::libc::SO_EE_ORIGIN_ICMP,
-            }
-        );
-    }
-
-    #[test]
-    fn classifies_timestamping_origin_with_wrong_completion_kind_as_malformed() {
-        // Same origin byte as a send-timestamp completion, but a different
-        // `ee_info` (e.g. SCM_TSTAMP_SCHED/ACK, which this client never
-        // requests). A timestamping-origin record must never become a
-        // fatal SocketError merely because it reports a completion kind we
-        // did not ask for; it stays timing metadata.
-        let cmsgs = vec![ControlMessageOwned::Ipv4RecvErr(
-            extended_error(
-                nix::libc::ENOMSG as u32,
-                nix::libc::SO_EE_ORIGIN_TIMESTAMPING,
-                1,
-                0,
-            ),
-            None,
-        )];
-
-        assert_eq!(
-            classify(cmsgs.into_iter()),
-            ErrorQueueRecord::MalformedOrUnsupportedTimestamp
-        );
-    }
-
-    #[test]
-    fn classifies_timestamping_origin_with_unexpected_errno_as_malformed() {
-        // Origin is the sole discriminator: even an origin==TIMESTAMPING
-        // record with a surprising errno (the kernel always reports ENOMSG
-        // for this origin, but classification must not assume that) is
-        // still timing metadata, never a real socket error.
-        let cmsgs = vec![ControlMessageOwned::Ipv4RecvErr(
-            extended_error(
-                nix::libc::ECONNREFUSED as u32,
-                nix::libc::SO_EE_ORIGIN_TIMESTAMPING,
-                SCM_TSTAMP_SND,
-                0,
-            ),
-            None,
-        )];
-
-        assert_eq!(
-            classify(cmsgs.into_iter()),
-            ErrorQueueRecord::MalformedOrUnsupportedTimestamp
-        );
-    }
-
-    #[test]
-    fn ignores_records_without_any_extended_error() {
-        let cmsgs = vec![ControlMessageOwned::Ipv4Tos(0)];
-
-        assert_eq!(classify(cmsgs.into_iter()), ErrorQueueRecord::Ignored);
-    }
-
-    #[test]
-    fn unknown_cmsgs_do_not_affect_classification() {
-        let cmsgs = vec![
-            ControlMessageOwned::Ipv4Tos(0),
-            send_timestamp_error(4),
-            ControlMessageOwned::ScmTimestampsns(timestamps_with_system(TimeSpec::new(9, 0))),
-        ];
-
-        assert_eq!(
-            classify(cmsgs.into_iter()),
-            ErrorQueueRecord::TxTimestamp {
-                id: 4,
-                timestamp: UNIX_EPOCH + Duration::new(9, 0),
-            }
-        );
-    }
-
-    #[test]
-    fn cmsg_order_does_not_affect_classification() {
-        let forward = classify(
-            vec![
-                send_timestamp_error(9),
-                ControlMessageOwned::ScmTimestampsns(timestamps_with_system(TimeSpec::new(5, 0))),
-            ]
-            .into_iter(),
-        );
-        let reversed = classify(
-            vec![
-                ControlMessageOwned::ScmTimestampsns(timestamps_with_system(TimeSpec::new(5, 0))),
-                send_timestamp_error(9),
-            ]
-            .into_iter(),
-        );
-
-        assert_eq!(forward, reversed);
-    }
-
-    /// Bounded poll for one error-queue record, since software TX timestamp
-    /// delivery is asynchronous even on loopback. Never sleeps hoping
-    /// delivery "probably" happened; it keeps polling until either a
-    /// record appears or the overall deadline passes.
-    fn poll_for_record(fd: RawFd, overall_timeout: Duration) -> Option<ErrorQueueRecord> {
-        let deadline = Instant::now() + overall_timeout;
-        loop {
-            if let Some(record) = try_recv_error_queue_record(fd).unwrap() {
-                return Some(record);
-            }
-            if Instant::now() >= deadline {
-                return None;
-            }
-            std::thread::yield_now();
-        }
-    }
-
-    fn tx_timestamped_loopback_socket() -> Option<(UdpSocket, UdpSocket)> {
-        let socket = UdpSocket::bind(SocketAddr::from(([127, 0, 0, 1], 0))).unwrap();
-        // Held for the caller's lifetime: if this peer socket were dropped,
-        // its port would close and subsequent sends would fail with
-        // ECONNREFUSED once the kernel reports ICMP port-unreachable.
-        let peer = UdpSocket::bind(SocketAddr::from(([127, 0, 0, 1], 0))).unwrap();
-        socket.connect(peer.local_addr().unwrap()).unwrap();
-
-        match setsockopt(&socket, sockopt::Timestamping, &TX_TIMESTAMPING_FLAGS) {
-            Ok(()) => Some((socket, peer)),
-            Err(error) => {
-                eprintln!(
-                    "skipping TX timestamping smoke test: kernel/container denied \
-                     SO_TIMESTAMPING TX flags: {error}"
-                );
-                None
-            }
-        }
-    }
-
-    #[test]
-    fn automatic_opt_id_increments_sequentially_across_separate_sends() {
-        let Some((socket, _peer)) = tx_timestamped_loopback_socket() else {
-            return;
-        };
-        let fd = socket.as_raw_fd();
-
-        // Under heavy parallel test load, loopback UDP sends can
-        // occasionally surface a stale ICMP-derived socket error unrelated
-        // to this test's own sockets. That is an environmental condition,
-        // not a claim this test makes about kernel TX timestamp behavior,
-        // so it is a skip rather than a failure.
-        if let Err(error) = socket.send(b"first") {
-            eprintln!("skipping automatic OPT_ID assertion: first send failed: {error}");
-            return;
-        }
-        let Some(first) = poll_for_record(fd, Duration::from_secs(2)) else {
-            eprintln!(
-                "skipping automatic OPT_ID assertion: no TX timestamp record was \
-                 delivered within the poll deadline"
-            );
-            return;
-        };
-        assert!(
-            matches!(first, ErrorQueueRecord::TxTimestamp { id: 0, .. }),
-            "expected first send to report id 0, got {first:?}"
-        );
-
-        if let Err(error) = socket.send(b"second") {
-            eprintln!("skipping automatic OPT_ID assertion: second send failed: {error}");
-            return;
-        }
-        let Some(second) = poll_for_record(fd, Duration::from_secs(2)) else {
-            eprintln!(
-                "skipping automatic OPT_ID assertion: no TX timestamp record was \
-                 delivered for the second send within the poll deadline"
-            );
-            return;
-        };
-        assert!(
-            matches!(second, ErrorQueueRecord::TxTimestamp { id: 1, .. }),
-            "expected second send to report id 1, got {second:?}"
-        );
-    }
-
-    #[test]
-    fn rx_only_sends_before_tx_enable_do_not_consume_the_later_tx_id_namespace() {
-        let socket = UdpSocket::bind(SocketAddr::from(([127, 0, 0, 1], 0))).unwrap();
-        let peer = UdpSocket::bind(SocketAddr::from(([127, 0, 0, 1], 0))).unwrap();
-        socket.connect(peer.local_addr().unwrap()).unwrap();
-        setsockopt(
-            &socket,
-            sockopt::Timestamping,
-            &super::super::RX_TIMESTAMPING_FLAGS,
-        )
-        .unwrap();
-
-        // Ordinary pre-enable sends: TX_SOFTWARE is not yet requested, so
-        // none of these may leave anything on the error queue for the
-        // later-enabled OPT_ID counter to have skipped past.
-        for _ in 0..3 {
-            if let Err(error) = socket.send(b"pre-enable") {
-                eprintln!("skipping pre-enable send/RX-only smoke test: {error}");
-                return;
-            }
-        }
-        assert_eq!(
-            try_recv_error_queue_record(socket.as_raw_fd()).unwrap(),
-            None,
-            "RX-only sends must never populate MSG_ERRQUEUE"
-        );
-
-        // This mirrors production: RX-only is configured first (e.g. at
-        // connect time), and only later, after a successful Open, is the
-        // socket upgraded to TX_TIMESTAMPING_FLAGS.
-        if setsockopt(&socket, sockopt::Timestamping, &TX_TIMESTAMPING_FLAGS).is_err() {
-            eprintln!(
-                "skipping pre-enable send/RX-only smoke test: kernel/container denied \
-                 SO_TIMESTAMPING TX flags"
-            );
-            return;
-        }
-
-        if let Err(error) = socket.send(b"first-timestamped") {
-            eprintln!(
-                "skipping pre-enable send/RX-only smoke test: post-upgrade send failed: {error}"
-            );
-            return;
-        }
-        let Some(record) = poll_for_record(socket.as_raw_fd(), Duration::from_secs(2)) else {
-            eprintln!(
-                "skipping pre-enable send/RX-only smoke test: no TX timestamp record was \
-                 delivered within the poll deadline"
-            );
-            return;
-        };
-        assert!(
-            matches!(record, ErrorQueueRecord::TxTimestamp { id: 0, .. }),
-            "expected the first send after upgrade to report id 0 (pre-enable sends must not \
-             have consumed part of the namespace), got {record:?}"
-        );
-    }
-
-    #[test]
-    fn normal_rx_scm_timestamping_still_works_after_tx_flags_are_enabled() {
-        let Some((socket, peer)) = tx_timestamped_loopback_socket() else {
-            return;
-        };
-        peer.send_to(b"reply", socket.local_addr().unwrap())
-            .unwrap();
-
-        let mut buf = [0_u8; 16];
-        let Ok(datagram) = super::super::recv_datagram(&socket, &mut buf) else {
-            eprintln!("skipping post-TX-enable RX smoke test: receive failed");
-            return;
-        };
-        assert_eq!(&buf[..datagram.len], b"reply");
-        let Some(timestamp) = datagram.meta.kernel_rx_timestamp else {
-            eprintln!(
-                "skipping post-TX-enable RX smoke test: kernel did not provide SCM_TIMESTAMPING"
-            );
-            return;
-        };
-        assert!(timestamp.duration_since(std::time::UNIX_EPOCH).unwrap() > Duration::ZERO);
-    }
-
-    #[test]
-    fn tx_timestamp_and_normal_reply_streams_do_not_interfere() {
-        let Some((socket, peer)) = tx_timestamped_loopback_socket() else {
-            return;
-        };
-        let fd = socket.as_raw_fd();
-
-        if let Err(error) = socket.send(b"ping") {
-            eprintln!("skipping TX/RX separation smoke test: ping send failed: {error}");
-            return;
-        }
-        let mut incoming = [0_u8; 16];
-        let Ok((len, from)) = peer.recv_from(&mut incoming) else {
-            eprintln!("skipping TX/RX separation smoke test: peer never observed ping");
-            return;
-        };
-        assert_eq!(&incoming[..len], b"ping");
-        peer.send_to(b"pong", from).unwrap();
-
-        // Reading the normal payload must not require, wait for, or be
-        // disturbed by draining MSG_ERRQUEUE first.
-        let mut reply_buf = [0_u8; 16];
-        let Ok(datagram) = super::super::recv_datagram(&socket, &mut reply_buf) else {
-            eprintln!("skipping TX/RX separation smoke test: normal receive failed");
-            return;
-        };
-        assert_eq!(&reply_buf[..datagram.len], b"pong");
-
-        // The TX timestamp for "ping" is still independently available on
-        // the error queue, unconsumed by the normal receive above.
-        let Some(record) = poll_for_record(fd, Duration::from_secs(2)) else {
-            eprintln!("skipping TX/RX separation smoke test: no TX timestamp record arrived");
-            return;
-        };
-        assert!(matches!(
-            record,
-            ErrorQueueRecord::TxTimestamp { id: 0, .. }
-        ));
-    }
-
-    #[test]
-    fn tx_timestamp_correlation_does_not_depend_on_original_payload() {
-        let Some((socket, _peer)) = tx_timestamped_loopback_socket() else {
-            return;
-        };
-
-        // OPT_TSONLY notifications never carry the original payload; a
-        // larger payload must classify identically to the zero-length one
-        // used elsewhere, since correlation is by `id` alone.
-        let payload = vec![0x5A_u8; 512];
-        if let Err(error) = socket.send(&payload) {
-            eprintln!("skipping OPT_TSONLY payload-independence smoke test: send failed: {error}");
-            return;
-        }
-        let Some(record) = poll_for_record(socket.as_raw_fd(), Duration::from_secs(2)) else {
-            eprintln!(
-                "skipping OPT_TSONLY payload-independence smoke test: no TX timestamp record \
-                 arrived"
-            );
-            return;
-        };
-        assert!(matches!(
-            record,
-            ErrorQueueRecord::TxTimestamp { id: 0, .. }
-        ));
-    }
-
-    // NOTE: a live test proving that a failed nonblocking `sendmsg` does not
-    // consume an automatic OPT_ID is not included here. Forcing a reliable,
-    // non-flaky `WouldBlock` on a connected loopback UDP socket (e.g. via
-    // socket-buffer saturation) has no deterministic OS-level mechanism
-    // available in this environment, and the repository's testing policy
-    // explicitly forbids faking coverage with sleep/saturation-based
-    // flakiness. That safety is instead established from Linux kernel
-    // source: `_sock_tx_timestamp` (include/net/sock.h) and
-    // `__ip_append_data`/`__ip6_append_data` (net/ipv4/ip_output.c,
-    // net/ipv6/ip6_output.c) increment `sk->sk_tskey` speculatively before
-    // a datagram is fully built and explicitly `atomic_dec` it back out on
-    // every error path (tracked via a local `hold_tskey` flag), so a failed
-    // send can never leave a gap in — or otherwise advance — the ID space
-    // the kernel hands out to successfully submitted datagrams. See the
-    // client crate's `AGENTS.md` for the full citation. The client-side
-    // half of this invariant (a `WouldBlock` `try_send` never advances the
-    // local wire-sequence counter used as the correlation ID) is covered by
-    // a deterministic test in the adapter module that injects `WouldBlock`.
-}

crates/irtt-client/src/session/negotiation.rs

@@ -346,180 +346,3 @@ fn record_restriction(
     restrictions.push(restriction);
     Ok(())
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use irtt_proto::{Clock, ReceivedStats, ServerFill, StampAt};
-
-    fn default_params() -> Params {
-        Params {
-            protocol_version: PROTOCOL_VERSION,
-            duration_ns: 3_000_000_000,
-            interval_ns: 1_000_000_000,
-            length: 256,
-            received_stats: ReceivedStats::Both,
-            stamp_at: StampAt::Both,
-            clock: Clock::Both,
-            // Raw wire TOS/Traffic Class byte for DSCP codepoint 46 (EF).
-            dscp: 184,
-            server_fill: Some(ServerFill {
-                value: "rand".to_owned(),
-            }),
-        }
-    }
-
-    fn assert_rejected(requested: &Params, returned: &Params, policy: NegotiationPolicy) {
-        assert!(matches!(
-            negotiate_params(requested, returned.clone(), policy),
-            Err(ClientError::NegotiationRejected { .. })
-        ));
-    }
-
-    fn assert_negotiates(
-        requested: &Params,
-        returned: &Params,
-        policy: NegotiationPolicy,
-    ) -> NegotiatedParams {
-        negotiate_params(requested, returned.clone(), policy)
-            .unwrap_or_else(|err| panic!("expected negotiation success, got {err:?}"))
-    }
-
-    fn rejection_reason(
-        requested: &Params,
-        returned: &Params,
-        policy: NegotiationPolicy,
-    ) -> String {
-        match negotiate_params(requested, returned.clone(), policy) {
-            Err(ClientError::NegotiationRejected { reason }) => reason,
-            other => panic!("expected negotiation rejection, got {other:?}"),
-        }
-    }
-
-    #[test]
-    fn strict_rejects_changed_negotiated_fields() {
-        let requested = default_params();
-
-        let mut returned = requested.clone();
-        returned.length = 128;
-        assert_eq!(
-            rejection_reason(&requested, &returned, NegotiationPolicy::Strict),
-            NegotiationRestriction::LengthReduced {
-                requested: requested.length,
-                negotiated: returned.length,
-            }
-            .message()
-        );
-
-        let mut returned = requested.clone();
-        returned.dscp = 0;
-        assert_eq!(
-            rejection_reason(&requested, &returned, NegotiationPolicy::Strict),
-            NegotiationRestriction::DscpChanged {
-                requested: requested.dscp >> 2,
-                negotiated: returned.dscp >> 2,
-            }
-            .message()
-        );
-
-        let mut returned = requested.clone();
-        returned.received_stats = ReceivedStats::Count;
-        assert_eq!(
-            rejection_reason(&requested, &returned, NegotiationPolicy::Strict),
-            NegotiationRestriction::ReceivedStatsChanged {
-                requested: requested.received_stats,
-                negotiated: returned.received_stats,
-            }
-            .message()
-        );
-
-        let mut returned = requested.clone();
-        returned.stamp_at = StampAt::Midpoint;
-        assert_eq!(
-            rejection_reason(&requested, &returned, NegotiationPolicy::Strict),
-            NegotiationRestriction::StampAtChanged {
-                requested: requested.stamp_at,
-                negotiated: returned.stamp_at,
-            }
-            .message()
-        );
-
-        let mut returned = requested.clone();
-        returned.clock = Clock::Wall;
-        assert_eq!(
-            rejection_reason(&requested, &returned, NegotiationPolicy::Strict),
-            NegotiationRestriction::ClockChanged {
-                requested: requested.clock,
-                negotiated: returned.clock,
-            }
-            .message()
-        );
-
-        let mut returned = requested.clone();
-        returned.server_fill = None;
-        assert_eq!(
-            rejection_reason(&requested, &returned, NegotiationPolicy::Strict),
-            NegotiationRestriction::ServerFillChanged.message()
-        );
-    }
-
-    #[test]
-    fn loose_duration_negotiation_uses_run_duration_semantics() {
-        let requested = default_params();
-
-        let mut returned = requested.clone();
-        returned.duration_ns = requested.duration_ns / 2;
-        let negotiated = assert_negotiates(&requested, &returned, NegotiationPolicy::Loose);
-        assert_eq!(
-            negotiated.restrictions,
-            vec![NegotiationRestriction::DurationReduced {
-                requested_ns: requested.duration_ns,
-                negotiated_ns: returned.duration_ns,
-            }]
-        );
-
-        let mut returned = requested.clone();
-        returned.duration_ns = requested.duration_ns + 1;
-        assert_eq!(
-            rejection_reason(&requested, &returned, NegotiationPolicy::Loose),
-            "duration increased"
-        );
-
-        let mut returned = requested.clone();
-        returned.duration_ns = 0;
-        assert_eq!(
-            rejection_reason(&requested, &returned, NegotiationPolicy::Loose),
-            "server returned continuous duration for finite request"
-        );
-
-        let mut continuous_requested = requested.clone();
-        continuous_requested.duration_ns = 0;
-        let mut finite_returned = continuous_requested.clone();
-        finite_returned.duration_ns = 1_000_000_000;
-        let negotiated = assert_negotiates(
-            &continuous_requested,
-            &finite_returned,
-            NegotiationPolicy::Loose,
-        );
-        assert_eq!(
-            negotiated.restrictions,
-            vec![NegotiationRestriction::DurationReduced {
-                requested_ns: 0,
-                negotiated_ns: finite_returned.duration_ns,
-            }]
-        );
-
-        assert_rejected(
-            &continuous_requested,
-            &finite_returned,
-            NegotiationPolicy::Strict,
-        );
-
-        assert!(negotiate_params(
-            &continuous_requested,
-            continuous_requested.clone(),
-            NegotiationPolicy::Strict
-        )
-        .is_ok());
-    }
-}

crates/irtt-client/src/socket.rs

@@ -12,6 +12,14 @@ use crate::{
     socket_options::apply_ttl_to_socket,
 };
 
+#[cfg(any(
+    target_os = "android",
+    target_os = "freebsd",
+    target_os = "fuchsia",
+    target_os = "linux"
+))]
+use crate::socket_options::apply_routing_options;
+
 pub(crate) fn validate_open_timeouts(timeouts: &[Duration]) -> Result<(), ClientError> {
     if timeouts.is_empty() {
         return Err(ClientError::NoOpenTimeouts);
@@ -28,9 +36,6 @@ pub(crate) fn validate_open_timeouts(timeouts: &[Duration]) -> Result<(), Client
 }
 
 pub(crate) fn resolve_remote(config: &ClientConfig) -> Result<SocketAddr, ClientError> {
-    #[cfg(all(test, feature = "tokio"))]
-    SYNC_RESOLVER_CALLS.with(|calls| calls.set(calls.get() + 1));
-
     let addr = normalize_server_addr(&config.server_addr);
     let mut addrs = addr
         .to_socket_addrs()
@@ -49,9 +54,6 @@ pub(crate) async fn resolve_remote_tokio(config: &ClientConfig) -> Result<Socket
             .ok_or(ClientError::Resolve { addr });
     }
 
-    #[cfg(all(test, feature = "tokio"))]
-    TOKIO_DNS_LOOKUPS.with(|calls| calls.set(calls.get() + 1));
-
     let mut addrs = tokio::net::lookup_host(&addr)
         .await
         .map_err(|_| ClientError::Resolve { addr: addr.clone() })?;
@@ -65,20 +67,6 @@ fn address_family_allowed(config: &ClientConfig, remote: SocketAddr) -> bool {
         && (!config.socket_config.ipv6_only || remote.is_ipv6())
 }
 
-#[cfg(all(test, feature = "tokio"))]
-std::thread_local! {
-    static SYNC_RESOLVER_CALLS: std::cell::Cell<usize> = const { std::cell::Cell::new(0) };
-    static TOKIO_DNS_LOOKUPS: std::cell::Cell<usize> = const { std::cell::Cell::new(0) };
-}
-
-#[cfg(all(test, feature = "tokio"))]
-pub(crate) fn resolution_call_counts() -> (usize, usize) {
-    (
-        SYNC_RESOLVER_CALLS.with(std::cell::Cell::get),
-        TOKIO_DNS_LOOKUPS.with(std::cell::Cell::get),
-    )
-}
-
 pub(crate) fn normalize_server_addr(addr: &str) -> String {
     if addr.parse::<SocketAddr>().is_ok() {
         return addr.to_owned();
@@ -115,6 +103,13 @@ fn create_connected_udp_socket(
     remote: SocketAddr,
 ) -> Result<UdpSocket, ClientError> {
     let socket = create_prebind_udp_socket(config, remote)?;
+    #[cfg(any(
+        target_os = "android",
+        target_os = "freebsd",
+        target_os = "fuchsia",
+        target_os = "linux"
+    ))]
+    apply_routing_options(&socket, config, remote)?;
     let bind_addr = config.bind_addr.unwrap_or_else(|| {
         if remote.is_ipv4() {
             SocketAddr::from(([0, 0, 0, 0], 0))
@@ -163,207 +158,3 @@ pub(crate) fn connect_tokio_udp_socket(
     socket.set_nonblocking(true)?;
     Ok(tokio::net::UdpSocket::from_std(socket)?)
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn normalize_server_addr_adds_default_ports() {
-        assert_eq!(normalize_server_addr("127.0.0.1"), "127.0.0.1:2112");
-        assert_eq!(normalize_server_addr("127.0.0.1:1234"), "127.0.0.1:1234");
-        assert_eq!(normalize_server_addr("localhost"), "localhost:2112");
-        assert_eq!(normalize_server_addr("localhost:1234"), "localhost:1234");
-        assert_eq!(normalize_server_addr("::1"), "[::1]:2112");
-        assert_eq!(normalize_server_addr("[::1]"), "[::1]:2112");
-        assert_eq!(normalize_server_addr("[::1]:1234"), "[::1]:1234");
-    }
-
-    #[test]
-    fn address_family_filtering_remains_unchanged() {
-        let ipv4 = SocketAddr::from(([127, 0, 0, 1], DEFAULT_PORT));
-        let ipv6 = SocketAddr::from(([0, 0, 0, 0, 0, 0, 0, 1], DEFAULT_PORT));
-        let mut config = ClientConfig::default();
-
-        assert!(address_family_allowed(&config, ipv4));
-        assert!(address_family_allowed(&config, ipv6));
-
-        config.socket_config.ipv4_only = true;
-        assert!(address_family_allowed(&config, ipv4));
-        assert!(!address_family_allowed(&config, ipv6));
-
-        config.socket_config.ipv4_only = false;
-        config.socket_config.ipv6_only = true;
-        assert!(!address_family_allowed(&config, ipv4));
-        assert!(address_family_allowed(&config, ipv6));
-    }
-
-    #[cfg(feature = "tokio")]
-    #[test]
-    fn tokio_ipv6_only_is_applied_before_bind() {
-        let config = SocketConfig {
-            ipv6_only: true,
-            ..SocketConfig::default()
-        };
-        let remote = SocketAddr::from(([0, 0, 0, 0, 0, 0, 0, 1], DEFAULT_PORT));
-
-        let socket = create_prebind_udp_socket(&config, remote).unwrap();
-
-        assert!(socket.only_v6().unwrap());
-    }
-
-    #[cfg(feature = "tokio")]
-    #[test]
-    fn tokio_ipv6_socket_preserves_v6only_and_explicit_bind() {
-        let bind_addr = SocketAddr::from(([0, 0, 0, 0, 0, 0, 0, 1], 0));
-        let peer = match UdpSocket::bind(bind_addr) {
-            Ok(peer) => peer,
-            Err(error) if ipv6_loopback_unavailable(&error) => {
-                eprintln!("skipping IPv6 Tokio socket test: IPv6 loopback unavailable: {error}");
-                return;
-            }
-            Err(error) => panic!("{error}"),
-        };
-        let remote = peer.local_addr().unwrap();
-        let config = SocketConfig {
-            bind_addr: Some(bind_addr),
-            ipv6_only: true,
-            ..SocketConfig::default()
-        };
-
-        tokio_runtime().block_on(async {
-            let socket = connect_tokio_udp_socket(&config, remote).unwrap();
-
-            assert!(socket2::SockRef::from(&socket).only_v6().unwrap());
-            assert!(socket.local_addr().unwrap().is_ipv6());
-            assert_eq!(socket.local_addr().unwrap().ip(), bind_addr.ip());
-            assert_eq!(socket.peer_addr().unwrap(), remote);
-        });
-    }
-
-    #[cfg(feature = "tokio")]
-    #[test]
-    fn tokio_ipv4_socket_preserves_family_bind_peer_and_ttl() {
-        let peer = UdpSocket::bind(SocketAddr::from(([127, 0, 0, 1], 0))).unwrap();
-        let remote = peer.local_addr().unwrap();
-        let bind_addr = SocketAddr::from(([127, 0, 0, 1], 0));
-        let config = SocketConfig {
-            bind_addr: Some(bind_addr),
-            ttl: Some(64),
-            ..SocketConfig::default()
-        };
-
-        tokio_runtime().block_on(async {
-            let socket = connect_tokio_udp_socket(&config, remote).unwrap();
-
-            assert!(socket.local_addr().unwrap().is_ipv4());
-            assert_eq!(socket.local_addr().unwrap().ip(), bind_addr.ip());
-            assert_eq!(socket.peer_addr().unwrap(), remote);
-            assert_eq!(socket2::SockRef::from(&socket).ttl_v4().unwrap(), 64);
-        });
-    }
-
-    #[cfg(feature = "tokio")]
-    #[test]
-    fn tokio_resolver_filters_families_without_using_blocking_resolution() {
-        let mut config = ClientConfig {
-            server_addr: "localhost:2112".to_owned(),
-            ..ClientConfig::default()
-        };
-        config.socket_config.ipv4_only = true;
-
-        tokio_runtime().block_on(async {
-            let before = resolution_call_counts();
-            let remote = resolve_remote_tokio(&config).await.unwrap();
-            let after = resolution_call_counts();
-
-            assert!(remote.is_ipv4());
-            assert_eq!(after.0, before.0);
-            assert_eq!(after.1, before.1 + 1);
-        });
-    }
-
-    #[cfg(feature = "tokio")]
-    #[test]
-    fn tokio_resolver_selects_ipv6_for_ipv6_only_hostname() {
-        let mut config = ClientConfig {
-            server_addr: "localhost:2112".to_owned(),
-            ..ClientConfig::default()
-        };
-        config.socket_config.ipv6_only = true;
-
-        tokio_runtime().block_on(async {
-            let remote = resolve_remote_tokio(&config).await.unwrap();
-            assert!(remote.is_ipv6());
-        });
-    }
-
-    #[cfg(feature = "tokio")]
-    #[test]
-    fn tokio_resolver_literal_path_bypasses_all_name_resolution() {
-        let config = ClientConfig {
-            server_addr: "127.0.0.1:2112".to_owned(),
-            ..ClientConfig::default()
-        };
-
-        tokio_runtime().block_on(async {
-            let before = resolution_call_counts();
-            let remote = resolve_remote_tokio(&config).await.unwrap();
-            let after = resolution_call_counts();
-
-            assert_eq!(remote, SocketAddr::from(([127, 0, 0, 1], 2112)));
-            assert_eq!(after, before);
-        });
-    }
-
-    #[cfg(feature = "tokio")]
-    #[test]
-    fn tokio_resolver_rejects_disallowed_literal_family() {
-        let mut config = ClientConfig {
-            server_addr: "127.0.0.1:2112".to_owned(),
-            ..ClientConfig::default()
-        };
-        config.socket_config.ipv6_only = true;
-
-        tokio_runtime().block_on(async {
-            assert!(matches!(
-                resolve_remote_tokio(&config).await,
-                Err(ClientError::Resolve { .. })
-            ));
-        });
-    }
-
-    #[cfg(feature = "tokio")]
-    #[test]
-    fn tokio_resolver_rejects_mixed_family_restrictions() {
-        let mut config = ClientConfig {
-            server_addr: "127.0.0.1:2112".to_owned(),
-            ..ClientConfig::default()
-        };
-        config.socket_config.ipv4_only = true;
-        config.socket_config.ipv6_only = true;
-
-        tokio_runtime().block_on(async {
-            assert!(matches!(
-                resolve_remote_tokio(&config).await,
-                Err(ClientError::Resolve { .. })
-            ));
-        });
-    }
-
-    #[cfg(feature = "tokio")]
-    fn tokio_runtime() -> tokio::runtime::Runtime {
-        tokio::runtime::Builder::new_current_thread()
-            .enable_io()
-            .build()
-            .unwrap()
-    }
-
-    #[cfg(feature = "tokio")]
-    fn ipv6_loopback_unavailable(error: &std::io::Error) -> bool {
-        matches!(
-            error.kind(),
-            std::io::ErrorKind::AddrNotAvailable | std::io::ErrorKind::Unsupported
-        )
-    }
-}

crates/irtt-client/src/socket_options.rs

@@ -5,11 +5,64 @@ use std::{
 
 use socket2::SockRef;
 
+#[cfg(any(
+    target_os = "android",
+    target_os = "freebsd",
+    target_os = "fuchsia",
+    target_os = "linux"
+))]
+use socket2::Socket;
+
 use crate::{
     config::{MAX_DSCP_CODEPOINT, MAX_TTL},
     error::ClientError,
 };
 
+#[cfg(any(
+    target_os = "android",
+    target_os = "freebsd",
+    target_os = "fuchsia",
+    target_os = "linux"
+))]
+pub(crate) fn apply_routing_options(
+    socket: &Socket,
+    config: &crate::SocketConfig,
+    remote: SocketAddr,
+) -> Result<(), ClientError> {
+    #[cfg(any(target_os = "android", target_os = "fuchsia", target_os = "linux"))]
+    {
+        if let Some(device) = &config.bind_to_device {
+            socket
+                .bind_device(Some(device.as_bytes()))
+                .map_err(|source| ClientError::SocketOption {
+                    operation: "bind socket to device",
+                    remote,
+                    source,
+                })?;
+        }
+        if let Some(mark) = config.mark {
+            socket
+                .set_mark(mark)
+                .map_err(|source| ClientError::SocketOption {
+                    operation: "set firewall mark",
+                    remote,
+                    source,
+                })?;
+        }
+    }
+    #[cfg(target_os = "freebsd")]
+    if let Some(fib) = config.fib {
+        socket
+            .set_fib(fib)
+            .map_err(|source| ClientError::SocketOption {
+                operation: "set FIB",
+                remote,
+                source,
+            })?;
+    }
+    Ok(())
+}
+
 /// Converts a public DSCP codepoint (`0..=`[`MAX_DSCP_CODEPOINT`]) into the
 /// raw IP TOS / Traffic Class byte it occupies the upper six bits of.
 ///
@@ -87,52 +140,15 @@ pub(crate) fn apply_ttl_to_socket(
     ttl: u32,
 ) -> Result<(), ClientError> {
     validate_ttl(ttl)?;
-    set_socket_ttl(socket, remote, ttl).map_err(|source| ClientError::SocketOption {
-        operation: "set TTL/hop limit",
-        remote,
-        source,
-    })
-}
-
-#[cfg(test)]
-pub(crate) fn socket_traffic_class(
-    socket: &UdpSocket,
-    remote: SocketAddr,
-) -> Result<u32, ClientError> {
-    get_socket_traffic_class(socket, remote).map_err(|source| ClientError::SocketOption {
-        operation: "read DSCP socket option",
-        remote,
-        source,
-    })
-}
-
-#[cfg(all(test, feature = "tokio"))]
-pub(crate) fn tokio_socket_traffic_class(
-    socket: &tokio::net::UdpSocket,
-    remote: SocketAddr,
-) -> Result<u32, ClientError> {
-    get_socket_traffic_class_ref(SockRef::from(socket), remote).map_err(|source| {
+    set_socket_ttl_ref(SockRef::from(socket), remote, ttl).map_err(|source| {
         ClientError::SocketOption {
-            operation: "read DSCP socket option",
+            operation: "set TTL/hop limit",
             remote,
             source,
         }
     })
 }
 
-#[cfg(test)]
-pub(crate) fn socket_ttl(socket: &UdpSocket, remote: SocketAddr) -> Result<u32, ClientError> {
-    get_socket_ttl(socket, remote).map_err(|source| ClientError::SocketOption {
-        operation: "read TTL/hop limit socket option",
-        remote,
-        source,
-    })
-}
-
-fn set_socket_ttl(socket: &UdpSocket, remote: SocketAddr, ttl: u32) -> io::Result<()> {
-    set_socket_ttl_ref(SockRef::from(socket), remote, ttl)
-}
-
 fn set_socket_ttl_ref(socket: SockRef<'_>, remote: SocketAddr, ttl: u32) -> io::Result<()> {
     if remote.is_ipv4() {
         socket.set_ttl_v4(ttl)
@@ -141,23 +157,13 @@ fn set_socket_ttl_ref(socket: SockRef<'_>, remote: SocketAddr, ttl: u32) -> io::
     }
 }
 
-#[cfg(test)]
-fn get_socket_ttl(socket: &UdpSocket, remote: SocketAddr) -> io::Result<u32> {
-    let socket = SockRef::from(socket);
-    if remote.is_ipv4() {
-        socket.ttl_v4()
-    } else {
-        socket.unicast_hops_v6()
-    }
-}
-
 fn set_socket_traffic_class(
     socket: &UdpSocket,
     remote: SocketAddr,
     traffic_class: u32,
     operation: &'static str,
 ) -> Result<(), ClientError> {
-    set_socket_traffic_class_io(socket, remote, traffic_class).map_err(|source| {
+    set_socket_traffic_class_ref(SockRef::from(socket), remote, traffic_class).map_err(|source| {
         ClientError::SocketOption {
             operation,
             remote,
@@ -166,14 +172,6 @@ fn set_socket_traffic_class(
     })
 }
 
-fn set_socket_traffic_class_io(
-    socket: &UdpSocket,
-    remote: SocketAddr,
-    traffic_class: u32,
-) -> io::Result<()> {
-    set_socket_traffic_class_ref(SockRef::from(socket), remote, traffic_class)
-}
-
 #[cfg(feature = "tokio")]
 fn set_tokio_socket_traffic_class(
     socket: &tokio::net::UdpSocket,
@@ -282,302 +280,3 @@ fn unsupported_traffic_class(traffic_class: u32, feature: &'static str) -> io::R
         ))
     }
 }
-
-#[cfg(all(
-    test,
-    not(any(
-        target_os = "fuchsia",
-        target_os = "redox",
-        target_os = "solaris",
-        target_os = "illumos",
-        target_os = "haiku",
-    ))
-))]
-fn get_ipv4_traffic_class(socket: SockRef<'_>) -> io::Result<u32> {
-    socket.tos_v4()
-}
-
-#[cfg(all(
-    test,
-    any(
-        target_os = "fuchsia",
-        target_os = "redox",
-        target_os = "solaris",
-        target_os = "illumos",
-        target_os = "haiku",
-    )
-))]
-fn get_ipv4_traffic_class(_socket: SockRef<'_>) -> io::Result<u32> {
-    unsupported_readback("IPv4 DSCP socket option readback")
-}
-
-#[cfg(all(
-    test,
-    any(
-        target_os = "android",
-        target_os = "dragonfly",
-        target_os = "freebsd",
-        target_os = "fuchsia",
-        target_os = "linux",
-        target_os = "macos",
-        target_os = "netbsd",
-        target_os = "openbsd",
-        target_os = "cygwin",
-    )
-))]
-fn get_ipv6_traffic_class(socket: SockRef<'_>) -> io::Result<u32> {
-    socket.tclass_v6()
-}
-
-#[cfg(all(
-    test,
-    not(any(
-        target_os = "android",
-        target_os = "dragonfly",
-        target_os = "freebsd",
-        target_os = "fuchsia",
-        target_os = "linux",
-        target_os = "macos",
-        target_os = "netbsd",
-        target_os = "openbsd",
-        target_os = "cygwin",
-    ))
-))]
-fn get_ipv6_traffic_class(_socket: SockRef<'_>) -> io::Result<u32> {
-    unsupported_readback("IPv6 DSCP socket option readback")
-}
-
-#[cfg(test)]
-fn get_socket_traffic_class(socket: &UdpSocket, remote: SocketAddr) -> io::Result<u32> {
-    get_socket_traffic_class_ref(SockRef::from(socket), remote)
-}
-
-#[cfg(test)]
-fn get_socket_traffic_class_ref(socket: SockRef<'_>, remote: SocketAddr) -> io::Result<u32> {
-    if remote.is_ipv4() {
-        get_ipv4_traffic_class(socket)
-    } else {
-        get_ipv6_traffic_class(socket)
-    }
-}
-
-#[cfg(all(
-    test,
-    any(
-        target_os = "fuchsia",
-        target_os = "redox",
-        target_os = "solaris",
-        target_os = "illumos",
-        target_os = "haiku",
-        not(any(
-            target_os = "android",
-            target_os = "dragonfly",
-            target_os = "freebsd",
-            target_os = "fuchsia",
-            target_os = "linux",
-            target_os = "macos",
-            target_os = "netbsd",
-            target_os = "openbsd",
-            target_os = "cygwin",
-        )),
-    )
-))]
-fn unsupported_readback(feature: &'static str) -> io::Result<u32> {
-    Err(io::Error::new(
-        io::ErrorKind::Unsupported,
-        format!("{feature} is unsupported on this target"),
-    ))
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn converts_dscp_codepoint_to_traffic_class_byte() {
-        for (dscp, traffic_class) in [(0, 0), (1, 4), (46, 184), (63, 252)] {
-            let value = dscp_codepoint_to_traffic_class(dscp).unwrap();
-            assert_eq!(value, traffic_class);
-            assert_eq!(value & 0b11, 0);
-        }
-    }
-
-    #[test]
-    fn rejects_out_of_range_dscp_codepoint() {
-        assert!(matches!(
-            dscp_codepoint_to_traffic_class(64),
-            Err(ClientError::InvalidConfig { .. })
-        ));
-    }
-
-    #[test]
-    fn validates_ttl_range() {
-        assert!(validate_ttl(1).is_ok());
-        assert!(validate_ttl(64).is_ok());
-        assert!(validate_ttl(255).is_ok());
-        assert!(matches!(
-            validate_ttl(0),
-            Err(ClientError::InvalidConfig { .. })
-        ));
-        assert!(matches!(
-            validate_ttl(256),
-            Err(ClientError::InvalidConfig { .. })
-        ));
-    }
-
-    #[test]
-    fn ipv4_socket_option_sets_ttl() {
-        let remote = SocketAddr::from(([127, 0, 0, 1], 9));
-        let socket = UdpSocket::bind(SocketAddr::from(([127, 0, 0, 1], 0))).unwrap();
-        socket.connect(remote).unwrap();
-
-        apply_ttl_to_socket(&socket, remote, 64).unwrap();
-        assert_eq!(socket_ttl(&socket, remote).unwrap(), 64);
-
-        apply_ttl_to_socket(&socket, remote, 1).unwrap();
-        assert_eq!(socket_ttl(&socket, remote).unwrap(), 1);
-    }
-
-    #[test]
-    fn ipv6_socket_option_sets_unicast_hop_limit() {
-        let remote = SocketAddr::from(([0, 0, 0, 0, 0, 0, 0, 1], 9));
-        let Some(socket) = bind_connected_ipv6_loopback(remote) else {
-            return;
-        };
-
-        apply_ttl_to_socket(&socket, remote, 64).unwrap();
-        let ttl = match socket_ttl(&socket, remote) {
-            Ok(ttl) => ttl,
-            Err(error) if is_unsupported_socket_readback(&error) => {
-                eprintln!("skipping IPv6 hop-limit readback test: {error}");
-                return;
-            }
-            Err(error) => panic!("{error}"),
-        };
-        assert_eq!(ttl, 64);
-
-        apply_ttl_to_socket(&socket, remote, 1).unwrap();
-        assert_eq!(socket_ttl(&socket, remote).unwrap(), 1);
-    }
-
-    #[test]
-    #[cfg(not(any(
-        target_os = "fuchsia",
-        target_os = "redox",
-        target_os = "solaris",
-        target_os = "illumos",
-        target_os = "haiku",
-    )))]
-    fn ipv4_socket_option_sets_and_clears_traffic_class() {
-        let remote = SocketAddr::from(([127, 0, 0, 1], 9));
-        let socket = UdpSocket::bind(SocketAddr::from(([127, 0, 0, 1], 0))).unwrap();
-        socket.connect(remote).unwrap();
-
-        // 184 is the raw wire TOS/Traffic Class byte for DSCP codepoint 46
-        // (EF); applying it directly must not shift it again.
-        apply_traffic_class_to_socket(&socket, remote, 184).unwrap();
-        assert_eq!(socket_traffic_class(&socket, remote).unwrap(), 184);
-
-        clear_dscp_on_socket(&socket, remote).unwrap();
-        assert_eq!(socket_traffic_class(&socket, remote).unwrap(), 0);
-    }
-
-    #[cfg(all(
-        feature = "tokio",
-        not(any(
-            target_os = "fuchsia",
-            target_os = "redox",
-            target_os = "solaris",
-            target_os = "illumos",
-            target_os = "haiku",
-        ))
-    ))]
-    #[test]
-    fn tokio_ipv4_socket_option_sets_and_clears_traffic_class() {
-        let runtime = tokio::runtime::Builder::new_current_thread()
-            .enable_io()
-            .build()
-            .unwrap();
-
-        runtime.block_on(async {
-            let remote = SocketAddr::from(([127, 0, 0, 1], 9));
-            let socket = UdpSocket::bind(SocketAddr::from(([127, 0, 0, 1], 0))).unwrap();
-            socket.connect(remote).unwrap();
-            socket.set_nonblocking(true).unwrap();
-            let socket = tokio::net::UdpSocket::from_std(socket).unwrap();
-
-            apply_traffic_class_to_tokio_socket(&socket, remote, 184).unwrap();
-            assert_eq!(tokio_socket_traffic_class(&socket, remote).unwrap(), 184);
-
-            clear_dscp_on_tokio_socket(&socket, remote).unwrap();
-            assert_eq!(tokio_socket_traffic_class(&socket, remote).unwrap(), 0);
-        });
-    }
-
-    #[test]
-    #[cfg(any(
-        target_os = "android",
-        target_os = "dragonfly",
-        target_os = "freebsd",
-        target_os = "fuchsia",
-        target_os = "linux",
-        target_os = "macos",
-        target_os = "netbsd",
-        target_os = "openbsd",
-        target_os = "cygwin",
-    ))]
-    fn ipv6_socket_option_sets_and_clears_traffic_class() {
-        let remote = SocketAddr::from(([0, 0, 0, 0, 0, 0, 0, 1], 9));
-        let Some(socket) = bind_connected_ipv6_loopback(remote) else {
-            return;
-        };
-
-        apply_traffic_class_to_socket(&socket, remote, 184).unwrap();
-        let traffic_class = match socket_traffic_class(&socket, remote) {
-            Ok(traffic_class) => traffic_class,
-            Err(error) if is_unsupported_socket_readback(&error) => {
-                eprintln!("skipping IPv6 traffic-class readback test: {error}");
-                return;
-            }
-            Err(error) => panic!("{error}"),
-        };
-        assert_eq!(traffic_class, 184);
-
-        clear_dscp_on_socket(&socket, remote).unwrap();
-        assert_eq!(socket_traffic_class(&socket, remote).unwrap(), 0);
-    }
-
-    fn bind_connected_ipv6_loopback(remote: SocketAddr) -> Option<UdpSocket> {
-        let socket = match UdpSocket::bind(SocketAddr::from(([0, 0, 0, 0, 0, 0, 0, 1], 0))) {
-            Ok(socket) => socket,
-            Err(error) if is_unavailable_ipv6_loopback(&error) => {
-                eprintln!("skipping IPv6 socket option test: IPv6 loopback unavailable: {error}");
-                return None;
-            }
-            Err(error) => panic!("{error}"),
-        };
-        match socket.connect(remote) {
-            Ok(()) => Some(socket),
-            Err(error) if is_unavailable_ipv6_loopback(&error) => {
-                eprintln!("skipping IPv6 socket option test: IPv6 loopback unavailable: {error}");
-                None
-            }
-            Err(error) => panic!("{error}"),
-        }
-    }
-
-    fn is_unavailable_ipv6_loopback(error: &io::Error) -> bool {
-        matches!(
-            error.kind(),
-            io::ErrorKind::AddrNotAvailable | io::ErrorKind::Unsupported
-        )
-    }
-
-    fn is_unsupported_socket_readback(error: &ClientError) -> bool {
-        matches!(
-            error,
-            ClientError::SocketOption { source, .. }
-                if matches!(source.kind(), io::ErrorKind::Unsupported)
-        )
-    }
-}

crates/irtt-client/tests/client.rs

@@ -0,0 +1,8 @@
+use irtt_client::*;
+use std::{
+    net::SocketAddr,
+    time::{Duration, Instant},
+};
+
+#[path = "client/mod.rs"]
+mod client;

crates/irtt-client/tests/client/close.rs

@@ -2,8 +2,7 @@ use super::*;
 
 #[test]
 fn open_fails_after_close() {
-    let config = default_test_config(SocketAddr::from(([127, 0, 0, 1], 1)));
-    let params = params_from_config(&config).unwrap();
+    let params = default_params();
     let server = start_fake_server(move |socket, tx| {
         let (_, peer) = recv_request(&socket, &tx);
         let reply = open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, None);
@@ -17,191 +16,6 @@ fn open_fails_after_close() {
     server.join();
 }
 
-#[test]
-fn close_sends_one_close_packet_with_negotiated_token() {
-    let config = default_test_config(SocketAddr::from(([127, 0, 0, 1], 1)));
-    let params = params_from_config(&config).unwrap();
-    let server = start_fake_server(move |socket, tx| {
-        let (_, peer) = recv_request(&socket, &tx);
-        let reply = open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, None);
-        socket.send_to(&reply, peer).unwrap();
-        let _ = recv_request(&socket, &tx);
-    });
-    let mut client = Client::connect(default_test_config(server.addr)).unwrap();
-    assert_open_started(client.open().unwrap());
-    let sent_at = ClientTimestamp {
-        wall: SystemTime::UNIX_EPOCH + Duration::from_secs(1_234),
-        mono: Instant::now() + Duration::from_secs(5),
-    };
-    client.test_hooks.close_sent_at.set(Some(sent_at));
-    let events = client.close().unwrap();
-    assert!(matches!(
-        events.as_slice(),
-        [ClientEvent::SessionClosed {
-            token: TOKEN,
-            at,
-            ..
-        }] if *at == sent_at
-    ));
-    assert!(!client.runtime.is_open());
-    assert!(client.schedule.is_none());
-    assert_eq!(client.applied_traffic_class, None);
-    let packets: Vec<_> = server.rx.iter().take(2).collect();
-    let close = &packets[1];
-    assert_eq!(close[3], flags::FLAG_CLOSE);
-    assert_eq!(u64::from_le_bytes(close[4..12].try_into().unwrap()), TOKEN);
-    server.join();
-}
-
-#[test]
-fn close_event_reservation_failure_precedes_dscp_clear_and_send() {
-    let params = default_params();
-    let server = start_fake_server(move |socket, tx| {
-        let (_, peer) = recv_request(&socket, &tx);
-        socket
-            .send_to(
-                &open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, None),
-                peer,
-            )
-            .unwrap();
-        let _ = recv_request(&socket, &tx);
-    });
-    let mut client = Client::connect(default_test_config(server.addr)).unwrap();
-    assert_open_started(client.open().unwrap());
-    client.test_hooks.fail_close_event_reserve.set(true);
-    client.test_hooks.fail_close_dscp_clear.set(true);
-
-    assert!(matches!(
-        client.close(),
-        Err(ClientError::AllocationFailed {
-            operation: "close event result",
-            ..
-        })
-    ));
-    assert_eq!(client.test_hooks.close_send_attempts.get(), 0);
-    assert!(client.test_hooks.fail_close_dscp_clear.get());
-    assert!(client.runtime.is_open());
-    assert!(client.schedule.is_some());
-    assert_eq!(client.applied_traffic_class, Some(0));
-
-    client.test_hooks.fail_close_dscp_clear.set(false);
-    client.close().unwrap();
-    assert_eq!(client.test_hooks.close_send_attempts.get(), 1);
-    server.join();
-}
-
-#[test]
-fn close_dscp_clear_failure_precedes_send_and_preserves_open_state() {
-    let params = default_params();
-    let server = start_fake_server(move |socket, tx| {
-        let (_, peer) = recv_request(&socket, &tx);
-        socket
-            .send_to(
-                &open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, None),
-                peer,
-            )
-            .unwrap();
-        let _ = recv_request(&socket, &tx);
-    });
-    let mut client = Client::connect(default_test_config(server.addr)).unwrap();
-    assert_open_started(client.open().unwrap());
-    client.test_hooks.fail_close_dscp_clear.set(true);
-
-    assert!(matches!(
-        client.close(),
-        Err(ClientError::SocketOption { .. })
-    ));
-    assert_eq!(client.test_hooks.close_send_attempts.get(), 0);
-    assert!(client.runtime.is_open());
-    assert!(client.schedule.is_some());
-    assert_eq!(client.applied_traffic_class, Some(0));
-
-    client.close().unwrap();
-    assert_eq!(client.test_hooks.close_send_attempts.get(), 1);
-    server.join();
-}
-
-#[test]
-fn close_send_failure_leaves_machine_and_schedule_open_for_retry() {
-    let params = default_params();
-    let server = start_fake_server(move |socket, tx| {
-        let (_, peer) = recv_request(&socket, &tx);
-        socket
-            .send_to(
-                &open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, None),
-                peer,
-            )
-            .unwrap();
-        let _ = recv_request(&socket, &tx);
-    });
-    let mut client = Client::connect(default_test_config(server.addr)).unwrap();
-    assert_open_started(client.open().unwrap());
-    let sent_at = ClientTimestamp {
-        wall: SystemTime::UNIX_EPOCH + Duration::from_secs(2_345),
-        mono: Instant::now() + Duration::from_secs(6),
-    };
-    client.test_hooks.close_sent_at.set(Some(sent_at));
-    client.test_hooks.fail_close_send.set(true);
-
-    assert!(matches!(client.close(), Err(ClientError::Socket(_))));
-    assert_eq!(client.test_hooks.close_sent_at.get(), Some(sent_at));
-    assert!(client.runtime.is_open());
-    assert!(client.schedule.is_some());
-    assert_eq!(client.applied_traffic_class, Some(0));
-    assert_eq!(client.test_hooks.close_send_attempts.get(), 1);
-
-    assert!(matches!(
-        client.close().unwrap().as_slice(),
-        [ClientEvent::SessionClosed {
-            token: TOKEN,
-            at,
-            ..
-        }] if *at == sent_at
-    ));
-    assert_eq!(client.test_hooks.close_sent_at.get(), None);
-    assert_eq!(client.test_hooks.close_send_attempts.get(), 2);
-    assert!(matches!(client.close(), Err(ClientError::AlreadyClosed)));
-    server.join();
-}
-
-#[test]
-fn short_successful_close_commits_before_length_mismatch() {
-    let params = default_params();
-    let server = start_fake_server(move |socket, tx| {
-        let (_, peer) = recv_request(&socket, &tx);
-        socket
-            .send_to(
-                &open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, None),
-                peer,
-            )
-            .unwrap();
-        let _ = recv_request(&socket, &tx);
-    });
-    let mut client = Client::connect(default_test_config(server.addr)).unwrap();
-    assert_open_started(client.open().unwrap());
-    let expected = client.runtime.prepare_close().unwrap().bytes.len();
-    let sent_at = ClientTimestamp {
-        wall: SystemTime::UNIX_EPOCH + Duration::from_secs(3_456),
-        mono: Instant::now() + Duration::from_secs(7),
-    };
-    client.test_hooks.close_sent_at.set(Some(sent_at));
-    client.test_hooks.close_reported_len.set(Some(expected - 1));
-
-    assert!(matches!(
-        client.close(),
-        Err(ClientError::DatagramLengthMismatch {
-            expected: error_expected,
-            actual,
-        }) if error_expected == expected && actual + 1 == expected
-    ));
-    assert!(!client.runtime.is_open());
-    assert!(client.schedule.is_none());
-    assert_eq!(client.applied_traffic_class, None);
-    assert_eq!(client.test_hooks.close_sent_at.get(), None);
-    assert!(matches!(client.close(), Err(ClientError::AlreadyClosed)));
-    server.join();
-}
-
 #[test]
 fn send_probe_fails_after_close() {
     let params = default_params();
@@ -232,135 +46,6 @@ fn send_probe_fails_after_close() {
     server.join();
 }
 
-#[test]
-fn close_flagged_echo_reply_emits_reply_then_closes_without_sending_close() {
-    let params = default_params();
-    let server = start_fake_server({
-        let params = params.clone();
-        move |socket, tx| {
-            let (_, peer) = recv_request(&socket, &tx);
-            let reply = open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, None);
-            socket.send_to(&reply, peer).unwrap();
-
-            let (request, _) = recv_request(&socket, &tx);
-            let seq = u32::from_le_bytes(request[12..16].try_into().unwrap());
-            let reply = echo_reply_packet_with_flags(
-                TOKEN,
-                seq,
-                &params,
-                &TimestampFields::default(),
-                None,
-                FLAG_REPLY | flags::FLAG_CLOSE,
-            );
-            socket.send_to(&reply, peer).unwrap();
-
-            socket
-                .set_read_timeout(Some(Duration::from_millis(250)))
-                .unwrap();
-            while recv_request_timeout(&socket, &tx).is_some() {}
-        }
-    });
-    let config = ClientConfig {
-        socket_config: crate::SocketConfig {
-            recv_timeout: Some(Duration::from_millis(200)),
-            ..Default::default()
-        },
-        ..default_test_config(server.addr)
-    };
-    let mut client = Client::connect(config).unwrap();
-    assert_open_started(client.open().unwrap());
-    client.send_probe().unwrap();
-
-    let events = client.recv_once().unwrap();
-    assert!(matches!(
-        events.first(),
-        Some(ClientEvent::EchoReply { .. })
-    ));
-    assert!(matches!(
-        events.get(1),
-        Some(ClientEvent::SessionClosed { token: TOKEN, .. })
-    ));
-    assert_eq!(events.len(), 2);
-    assert!(client.next_send_deadline().is_none());
-    assert!(client.schedule.is_none());
-    assert!(matches!(
-        client.send_probe(),
-        Err(ClientError::AlreadyClosed)
-    ));
-
-    let first = server.rx.recv_timeout(Duration::from_millis(100)).unwrap();
-    let second = server.rx.recv_timeout(Duration::from_millis(100)).unwrap();
-    assert_eq!(first[3] & FLAG_OPEN, FLAG_OPEN);
-    assert_eq!(second[3] & flags::FLAG_CLOSE, 0);
-    assert!(server.rx.recv_timeout(Duration::from_millis(400)).is_err());
-    server.join();
-}
-
-#[test]
-fn peer_close_dscp_cleanup_failure_preserves_events_and_closed_state() {
-    let params = default_params();
-    let server = start_fake_server({
-        let params = params.clone();
-        move |socket, tx| {
-            let (_, peer) = recv_request(&socket, &tx);
-            socket
-                .send_to(
-                    &open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, None),
-                    peer,
-                )
-                .unwrap();
-            let (request, _) = recv_request(&socket, &tx);
-            let seq = u32::from_le_bytes(request[12..16].try_into().unwrap());
-            socket
-                .send_to(
-                    &echo_reply_packet_with_flags(
-                        TOKEN,
-                        seq,
-                        &params,
-                        &TimestampFields::default(),
-                        None,
-                        FLAG_REPLY | flags::FLAG_CLOSE,
-                    ),
-                    peer,
-                )
-                .unwrap();
-            socket
-                .set_read_timeout(Some(Duration::from_millis(250)))
-                .unwrap();
-            while recv_request_timeout(&socket, &tx).is_some() {}
-        }
-    });
-    let mut client = Client::connect(ClientConfig {
-        socket_config: crate::SocketConfig {
-            recv_timeout: Some(Duration::from_millis(200)),
-            ..Default::default()
-        },
-        ..default_test_config(server.addr)
-    })
-    .unwrap();
-    assert_open_started(client.open().unwrap());
-    client.send_probe().unwrap();
-    client.test_hooks.fail_close_dscp_clear.set(true);
-
-    assert!(matches!(
-        client.recv_once().unwrap().as_slice(),
-        [
-            ClientEvent::EchoReply { .. },
-            ClientEvent::SessionClosed { token: TOKEN, .. }
-        ]
-    ));
-    assert!(client.is_peer_closed());
-    assert!(client.schedule.is_none());
-    assert_eq!(client.applied_traffic_class, Some(0));
-    assert_eq!(client.test_hooks.close_send_attempts.get(), 0);
-    let open = server.rx.recv_timeout(Duration::from_millis(100)).unwrap();
-    let echo = server.rx.recv_timeout(Duration::from_millis(100)).unwrap();
-    assert_ne!(open[3] & FLAG_OPEN, 0);
-    assert_eq!(echo[3] & flags::FLAG_CLOSE, 0);
-    assert!(server.rx.recv_timeout(Duration::from_millis(400)).is_err());
-    server.join();
-}
-
 #[test]
 fn recv_available_stops_after_peer_close() {
     let params = default_params();
@@ -407,21 +92,6 @@ fn recv_available_stops_after_peer_close() {
     server.join();
 }
 
-#[test]
-fn normal_echo_reply_does_not_close_session() {
-    let params = default_params();
-    let (mut client, server) = open_client_with_echo_server(&params);
-    client.send_probe().unwrap();
-
-    let events = client.recv_once().unwrap();
-    assert!(matches!(events.as_slice(), [ClientEvent::EchoReply { .. }]));
-    assert!(client.next_send_deadline().is_some());
-    assert!(client.send_probe().is_ok());
-
-    client.close().unwrap();
-    server.join();
-}
-
 #[test]
 fn close_flagged_duplicate_emits_duplicate_then_closes() {
     let params = default_params();
@@ -452,7 +122,7 @@ fn close_flagged_duplicate_emits_duplicate_then_closes() {
         }
     });
     let mut client = Client::connect(ClientConfig {
-        socket_config: crate::SocketConfig {
+        socket_config: irtt_client::SocketConfig {
             recv_timeout: Some(Duration::from_millis(200)),
             ..Default::default()
         },
@@ -510,7 +180,7 @@ fn close_flagged_retained_timeout_emits_late_then_closes() {
     });
     let mut client = Client::connect(ClientConfig {
         probe_timeout: Duration::from_millis(50),
-        socket_config: crate::SocketConfig {
+        socket_config: irtt_client::SocketConfig {
             recv_timeout: Some(Duration::from_millis(200)),
             ..Default::default()
         },
@@ -605,7 +275,7 @@ fn close_flagged_evicted_sequence_emits_late_then_closes() {
     });
     let mut client = Client::connect(ClientConfig {
         max_pending_probes: 1,
-        socket_config: crate::SocketConfig {
+        socket_config: irtt_client::SocketConfig {
             recv_timeout: Some(Duration::from_millis(200)),
             ..Default::default()
         },
@@ -669,7 +339,7 @@ fn close_flagged_untracked_sequence_emits_warning_then_closes() {
         }
     });
     let mut client = Client::connect(ClientConfig {
-        socket_config: crate::SocketConfig {
+        socket_config: irtt_client::SocketConfig {
             recv_timeout: Some(Duration::from_millis(200)),
             ..Default::default()
         },
@@ -727,7 +397,7 @@ fn wrong_token_close_flag_does_not_close_session() {
         }
     });
     let mut client = Client::connect(ClientConfig {
-        socket_config: crate::SocketConfig {
+        socket_config: irtt_client::SocketConfig {
             recv_timeout: Some(Duration::from_millis(200)),
             ..Default::default()
         },
@@ -752,3 +422,66 @@ fn wrong_token_close_flag_does_not_close_session() {
     client.close().unwrap();
     server.join();
 }
+
+#[test]
+fn close_flagged_echo_reply_emits_reply_then_closes_without_sending_close() {
+    let params = default_params();
+    let server = start_fake_server({
+        let params = params.clone();
+        move |socket, tx| {
+            let (_, peer) = recv_request(&socket, &tx);
+            let reply = open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, None);
+            socket.send_to(&reply, peer).unwrap();
+
+            let (request, _) = recv_request(&socket, &tx);
+            let seq = u32::from_le_bytes(request[12..16].try_into().unwrap());
+            let reply = echo_reply_packet_with_flags(
+                TOKEN,
+                seq,
+                &params,
+                &TimestampFields::default(),
+                None,
+                FLAG_REPLY | flags::FLAG_CLOSE,
+            );
+            socket.send_to(&reply, peer).unwrap();
+
+            socket
+                .set_read_timeout(Some(Duration::from_millis(250)))
+                .unwrap();
+            while recv_request_timeout(&socket, &tx).is_some() {}
+        }
+    });
+    let config = ClientConfig {
+        socket_config: irtt_client::SocketConfig {
+            recv_timeout: Some(Duration::from_millis(200)),
+            ..Default::default()
+        },
+        ..default_test_config(server.addr)
+    };
+    let mut client = Client::connect(config).unwrap();
+    assert_open_started(client.open().unwrap());
+    client.send_probe().unwrap();
+
+    let events = client.recv_once().unwrap();
+    assert!(matches!(
+        events.first(),
+        Some(ClientEvent::EchoReply { .. })
+    ));
+    assert!(matches!(
+        events.get(1),
+        Some(ClientEvent::SessionClosed { token: TOKEN, .. })
+    ));
+    assert_eq!(events.len(), 2);
+
+    assert!(matches!(
+        client.send_probe(),
+        Err(ClientError::AlreadyClosed)
+    ));
+
+    let first = server.rx.recv_timeout(Duration::from_millis(100)).unwrap();
+    let second = server.rx.recv_timeout(Duration::from_millis(100)).unwrap();
+    assert_eq!(first[3] & FLAG_OPEN, FLAG_OPEN);
+    assert_eq!(second[3] & flags::FLAG_CLOSE, 0);
+    assert!(server.rx.recv_timeout(Duration::from_millis(400)).is_err());
+    server.join();
+}

crates/irtt-client/tests/client/config.rs

@@ -1,93 +1,7 @@
 use super::*;
 
 #[test]
-fn client_config_default() {
-    let config = ClientConfig::default();
-    assert_eq!(config.duration, Some(Duration::from_secs(3)));
-    assert_eq!(config.interval, Duration::from_secs(1));
-    assert_eq!(config.length, 0);
-    assert_eq!(config.received_stats, ReceivedStats::Both);
-    assert_eq!(config.stamp_at, StampAt::Both);
-    assert_eq!(config.clock, Clock::Both);
-    assert_eq!(config.dscp, 0);
-    assert_eq!(config.hmac_key, None);
-    assert_eq!(config.server_fill, None);
-    assert_eq!(config.open_timeouts, DEFAULT_OPEN_TIMEOUTS);
-    assert_eq!(config.run_mode, RunMode::Normal);
-    assert_eq!(config.negotiation_policy, NegotiationPolicy::Strict);
-    assert_eq!(config.probe_timeout, Duration::from_secs(4));
-    assert_eq!(config.max_pending_probes, 4096);
-}
-
-#[test]
-fn params_from_config_maps_compatibility_fields() {
-    let config = ClientConfig {
-        duration: Some(Duration::from_secs(5)),
-        interval: Duration::from_millis(250),
-        length: 1472,
-        received_stats: ReceivedStats::Window,
-        stamp_at: StampAt::Midpoint,
-        clock: Clock::Wall,
-        dscp: 46,
-        hmac_key: Some(b"secret".to_vec()),
-        server_fill: Some("rand".to_owned()),
-        ..ClientConfig::default()
-    };
-
-    let params = params_from_config(&config).unwrap();
-    assert_eq!(params.protocol_version, PROTOCOL_VERSION);
-    assert_eq!(params.duration_ns, 5_000_000_000);
-    assert_eq!(params.interval_ns, 250_000_000);
-    assert_eq!(params.length, 1472);
-    assert_eq!(params.received_stats, ReceivedStats::Window);
-    assert_eq!(params.stamp_at, StampAt::Midpoint);
-    assert_eq!(params.clock, Clock::Wall);
-    assert_eq!(
-        params.dscp, 184,
-        "config DSCP codepoint 46 must be shifted into raw wire byte 184"
-    );
-    assert_eq!(
-        params.server_fill.as_ref().map(|fill| fill.value.as_str()),
-        Some("rand")
-    );
-    assert_eq!(config.hmac_key.as_deref(), Some(b"secret".as_slice()));
-}
-
-#[test]
-fn params_from_config_accepts_boundary_values() {
-    for length in [0, 1, 1472, 4096, MAX_UDP_PAYLOAD_LENGTH] {
-        let config = ClientConfig {
-            length,
-            ..ClientConfig::default()
-        };
-        assert_eq!(
-            params_from_config(&config).unwrap().length,
-            i64::from(length)
-        );
-    }
-
-    let config = ClientConfig {
-        dscp: 63,
-        ..ClientConfig::default()
-    };
-    assert_eq!(
-        params_from_config(&config).unwrap().dscp,
-        252,
-        "boundary codepoint 63 must be shifted into raw wire byte 252"
-    );
-}
-
-#[test]
-fn params_from_config_encodes_continuous_duration_as_zero() {
-    let config = ClientConfig {
-        duration: None,
-        ..ClientConfig::default()
-    };
-    assert_eq!(params_from_config(&config).unwrap().duration_ns, 0);
-}
-
-#[test]
-fn params_from_config_rejects_invalid_values() {
+fn connect_rejects_invalid_configuration() {
     let i64_max_ns = u64::try_from(i64::MAX).unwrap();
     let too_large = Duration::from_nanos(i64_max_ns) + Duration::from_nanos(1);
     let cases = [
@@ -170,10 +84,10 @@ fn params_from_config_rejects_invalid_values() {
     for (name, config, expected_reason) in cases {
         assert!(
             matches!(
-                params_from_config(&config),
-                Err(ClientError::InvalidConfig { reason }) if reason.contains(expected_reason)
+                Client::connect(config),
+                Err(ClientError::InvalidConfig { .. })
             ),
-            "{name} should fail with InvalidConfig containing {expected_reason:?}"
+            "{name} should fail with InvalidConfig ({expected_reason})"
         );
     }
 }

crates/irtt-client/tests/client/hmac.rs

@@ -0,0 +1,76 @@
+use super::*;
+
+#[test]
+fn hmac_open_ignores_missing_hmac_before_valid_reply() {
+    let key = b"secret".to_vec();
+    let mut config = default_test_config(SocketAddr::from(([127, 0, 0, 1], 1)));
+    config.hmac_key = Some(key.clone());
+    let params = default_params();
+    let server = start_fake_server(move |socket, tx| {
+        let (_, peer) = recv_request(&socket, &tx);
+        let missing = open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, None);
+        let valid = open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, Some(&key));
+        socket.send_to(&missing, peer).unwrap();
+        socket.send_to(&valid, peer).unwrap();
+    });
+    config.server_addr = server.addr.to_string();
+    let mut client = Client::connect(config).unwrap();
+    assert_open_started(client.open().unwrap());
+    assert_eq!(server.rx.iter().take(1).count(), 1);
+    assert!(server.rx.try_recv().is_err());
+    server.join();
+}
+
+#[test]
+fn hmac_open_ignores_bad_hmac_before_valid_reply() {
+    let key = b"secret".to_vec();
+    let wrong_key = b"wrong".to_vec();
+    let mut config = default_test_config(SocketAddr::from(([127, 0, 0, 1], 1)));
+    config.hmac_key = Some(key.clone());
+    let params = default_params();
+    let server = start_fake_server(move |socket, tx| {
+        let (_, peer) = recv_request(&socket, &tx);
+        let bad = open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, Some(&wrong_key));
+        let valid = open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, Some(&key));
+        socket.send_to(&bad, peer).unwrap();
+        socket.send_to(&valid, peer).unwrap();
+    });
+    config.server_addr = server.addr.to_string();
+    let mut client = Client::connect(config).unwrap();
+    assert_open_started(client.open().unwrap());
+    assert_eq!(server.rx.iter().take(1).count(), 1);
+    assert!(server.rx.try_recv().is_err());
+    server.join();
+}
+
+#[test]
+fn post_token_hmac_negotiation_failure_sends_authenticated_cleanup_close() {
+    let key = b"secret".to_vec();
+    let mut config = default_test_config(SocketAddr::from(([127, 0, 0, 1], 1)));
+    config.hmac_key = Some(key.clone());
+    let mut returned = default_params();
+    returned.interval_ns += 1;
+    let server_key = key.clone();
+    let server = start_fake_server(move |socket, tx| {
+        let (_, peer) = recv_request(&socket, &tx);
+        let reply = open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &returned, Some(&server_key));
+        socket.send_to(&reply, peer).unwrap();
+        let _ = recv_request(&socket, &tx);
+    });
+    config.server_addr = server.addr.to_string();
+    let mut client = Client::connect(config).unwrap();
+
+    assert!(matches!(
+        client.open(),
+        Err(ClientError::NegotiationRejected { .. })
+    ));
+    let packets: Vec<_> = server.rx.iter().take(2).collect();
+    let cleanup = &packets[1];
+    assert_eq!(cleanup[3], flags::FLAG_CLOSE | FLAG_HMAC);
+    verify_packet_hmac(&key, cleanup).unwrap();
+    assert_eq!(
+        u64::from_le_bytes(cleanup[4 + HMAC_SIZE..12 + HMAC_SIZE].try_into().unwrap()),
+        TOKEN
+    );
+    server.join();
+}

crates/irtt-client/tests/client/mod.rs

@@ -0,0 +1,22 @@
+use super::*;
+use irtt_client::NegotiationPolicy;
+use irtt_client::{NegotiatedParams, RunMode, WarningKind, MAX_UDP_PAYLOAD_LENGTH};
+use irtt_proto::{flags, Params, TimestampFields};
+use irtt_proto::{
+    flags::FLAG_HMAC, flags::FLAG_OPEN, flags::FLAG_REPLY, verify_packet_hmac, Clock, HMAC_SIZE,
+    MAGIC,
+};
+use std::thread;
+#[cfg(all(target_os = "linux", feature = "ancillary"))]
+use std::time::SystemTime;
+
+mod support;
+use support::*;
+
+mod close;
+mod config;
+mod hmac;
+mod no_test;
+mod open;
+mod probes_replies;
+mod ttl;

crates/irtt-client/tests/client/no_test.rs

@@ -1,27 +1,10 @@
 use super::*;
 
-#[test]
-fn no_test_success_validates_params() {
-    let mut config = default_test_config(SocketAddr::from(([127, 0, 0, 1], 1)));
-    config.run_mode = RunMode::NoTest;
-    let params = params_from_config(&config).unwrap();
-    let server = no_test_server(params.clone(), 0);
-    config.server_addr = server.addr.to_string();
-    let mut client = Client::connect(config).unwrap();
-    assert!(client.next_send_deadline().is_none());
-    let negotiated = assert_no_test_completed(client.open().unwrap());
-    assert_eq!(negotiated.params, params);
-    assert!(client.next_send_deadline().is_none());
-    assert!(client.schedule.is_none());
-    assert_eq!(client.applied_traffic_class, None);
-    server.join();
-}
-
 #[test]
 fn no_test_rejects_non_close_open_reply() {
     let mut config = default_test_config(SocketAddr::from(([127, 0, 0, 1], 1)));
     config.run_mode = RunMode::NoTest;
-    let params = params_from_config(&config).unwrap();
+    let params = default_params();
     let server = start_fake_server(move |socket, tx| {
         let (_, peer) = recv_request(&socket, &tx);
         socket
@@ -44,33 +27,6 @@ fn no_test_rejects_non_close_open_reply() {
         u64::from_le_bytes(packets[1][4..12].try_into().unwrap()),
         TOKEN
     );
-    assert!(client.runtime.prepare_open_request().is_ok());
-    server.join();
-}
-
-#[test]
-fn no_test_cleanup_send_failure_preserves_unexpected_reply() {
-    let mut config = default_test_config(SocketAddr::from(([127, 0, 0, 1], 1)));
-    config.run_mode = RunMode::NoTest;
-    let params = params_from_config(&config).unwrap();
-    let server = start_fake_server(move |socket, tx| {
-        let (_, peer) = recv_request(&socket, &tx);
-        socket
-            .send_to(
-                &open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, None),
-                peer,
-            )
-            .unwrap();
-    });
-    config.server_addr = server.addr.to_string();
-    let mut client = Client::connect(config).unwrap();
-    client.test_hooks.fail_cleanup_send.set(true);
-
-    assert!(matches!(
-        client.open(),
-        Err(ClientError::UnexpectedNoTestReply)
-    ));
-    assert!(client.runtime.prepare_open_request().is_ok());
     server.join();
 }
 
@@ -78,7 +34,7 @@ fn no_test_cleanup_send_failure_preserves_unexpected_reply() {
 fn no_test_rejects_non_zero_token_with_close_reply() {
     let mut config = default_test_config(SocketAddr::from(([127, 0, 0, 1], 1)));
     config.run_mode = RunMode::NoTest;
-    let params = params_from_config(&config).unwrap();
+    let params = default_params();
     let server = no_test_server(params, TOKEN);
     config.server_addr = server.addr.to_string();
     let mut client = Client::connect(config).unwrap();
@@ -93,7 +49,7 @@ fn no_test_rejects_non_zero_token_with_close_reply() {
 fn no_test_strict_negotiation_rejects_changed_params() {
     let mut config = default_test_config(SocketAddr::from(([127, 0, 0, 1], 1)));
     config.run_mode = RunMode::NoTest;
-    let mut params = params_from_config(&config).unwrap();
+    let mut params = default_params();
     params.dscp = 1;
     let server = no_test_server(params, 0);
     config.server_addr = server.addr.to_string();
@@ -110,7 +66,7 @@ fn no_test_loose_negotiation_accepts_restricted_params() {
     let mut config = default_test_config(SocketAddr::from(([127, 0, 0, 1], 1)));
     config.run_mode = RunMode::NoTest;
     config.negotiation_policy = NegotiationPolicy::Loose;
-    let requested = params_from_config(&config).unwrap();
+    let requested = default_params();
     let mut params = requested.clone();
     params.duration_ns /= 2;
     let server = no_test_server(params.clone(), 0);
@@ -120,7 +76,7 @@ fn no_test_loose_negotiation_accepts_restricted_params() {
     assert_eq!(negotiated.params, params);
     assert_eq!(
         negotiated.restrictions,
-        vec![crate::NegotiationRestriction::DurationReduced {
+        vec![irtt_client::NegotiationRestriction::DurationReduced {
             requested_ns: requested.duration_ns,
             negotiated_ns: params.duration_ns,
         }]
@@ -132,7 +88,7 @@ fn no_test_loose_negotiation_accepts_restricted_params() {
 fn send_probe_fails_after_no_test_completed() {
     let mut config = default_test_config(SocketAddr::from(([127, 0, 0, 1], 1)));
     config.run_mode = RunMode::NoTest;
-    let params = params_from_config(&config).unwrap();
+    let params = default_params();
     let server = no_test_server(params, 0);
     config.server_addr = server.addr.to_string();
     let mut client = Client::connect(config).unwrap();
@@ -148,7 +104,7 @@ fn send_probe_fails_after_no_test_completed() {
 fn open_fails_after_no_test_completed() {
     let mut config = default_test_config(SocketAddr::from(([127, 0, 0, 1], 1)));
     config.run_mode = RunMode::NoTest;
-    let params = params_from_config(&config).unwrap();
+    let params = default_params();
     let server = no_test_server(params, 0);
     config.server_addr = server.addr.to_string();
     let mut client = Client::connect(config).unwrap();

crates/irtt-client/tests/client/open.rs

@@ -0,0 +1,254 @@
+use super::*;
+
+// Untrusted returned intervals must be rejected before managed scheduling,
+// even when loose negotiation permits legitimate server restrictions.
+#[test]
+fn loose_open_rejects_nonpositive_returned_intervals() {
+    for interval_ns in [0, -1] {
+        let mut returned = default_params();
+        returned.interval_ns = interval_ns;
+        let server = open_success_server(returned);
+        let config = ClientConfig {
+            negotiation_policy: NegotiationPolicy::Loose,
+            ..default_test_config(server.addr)
+        };
+        let mut client = Client::connect(config).unwrap();
+        assert!(
+            matches!(client.open(), Err(ClientError::NegotiationRejected { .. })),
+            "returned interval {interval_ns} must be rejected"
+        );
+        server.join();
+    }
+}
+
+#[test]
+fn open_fails_when_already_open() {
+    let params = default_params();
+    let server = open_success_server(params);
+    let mut client = Client::connect(default_test_config(server.addr)).unwrap();
+    assert_open_started(client.open().unwrap());
+    assert!(matches!(client.open(), Err(ClientError::AlreadyOpen)));
+    server.join();
+}
+
+#[test]
+fn open_retries_after_first_timeout() {
+    let server = start_fake_server(|socket, tx| {
+        let (first, _) = recv_request(&socket, &tx);
+        let (_, peer) = recv_request(&socket, &tx);
+        let params = Params::decode(&first[4..]).unwrap();
+        let reply = open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, None);
+        assert_eq!(first[3] & FLAG_OPEN, FLAG_OPEN);
+        socket.send_to(&reply, peer).unwrap();
+    });
+    let config = ClientConfig {
+        open_timeouts: vec![Duration::from_millis(200), Duration::from_millis(500)],
+        ..default_test_config(server.addr)
+    };
+    let mut client = Client::connect(config).unwrap();
+    let outcome = client.open().unwrap();
+    assert_open_started(outcome);
+    assert_eq!(server.rx.iter().take(2).count(), 2);
+    server.join();
+}
+
+#[test]
+fn protocol_version_mismatch_fails() {
+    let mut config = default_test_config(SocketAddr::from(([127, 0, 0, 1], 1)));
+    config.negotiation_policy = NegotiationPolicy::Loose;
+    let mut params = default_params();
+    params.protocol_version = 2;
+    let server = open_success_server(params);
+    let mut client = Client::connect(default_test_config(server.addr)).unwrap();
+    assert!(matches!(
+        client.open(),
+        Err(ClientError::ProtocolVersionMismatch { received: 2, .. })
+    ));
+    assert_eq!(server.rx.iter().take(1).count(), 1);
+    server.join();
+}
+
+#[test]
+fn server_rejection_fails_in_normal_mode() {
+    let params = default_params();
+    let server = start_fake_server(move |socket, tx| {
+        let (_, peer) = recv_request(&socket, &tx);
+        let reply = open_reply(FLAG_OPEN | FLAG_REPLY | flags::FLAG_CLOSE, 0, &params, None);
+        socket.send_to(&reply, peer).unwrap();
+    });
+    let mut client = Client::connect(default_test_config(server.addr)).unwrap();
+    assert!(matches!(client.open(), Err(ClientError::ServerRejected)));
+    assert_eq!(server.rx.iter().take(1).count(), 1);
+    server.join();
+}
+
+#[test]
+fn ignored_datagrams_do_not_restart_the_attempt_deadline() {
+    let server = start_fake_server(move |socket, tx| {
+        let (_, peer) = recv_request(&socket, &tx);
+        thread::sleep(Duration::from_millis(150));
+        socket.send_to(&[0_u8], peer).unwrap();
+        thread::sleep(Duration::from_millis(150));
+        socket.send_to(&[0_u8], peer).unwrap();
+        let _ = recv_request(&socket, &tx);
+    });
+    let config = ClientConfig {
+        open_timeouts: vec![Duration::from_millis(250), Duration::from_millis(250)],
+        ..default_test_config(server.addr)
+    };
+    let mut client = Client::connect(config).unwrap();
+    let started = Instant::now();
+
+    assert!(matches!(client.open(), Err(ClientError::OpenTimeout)));
+    let requests: Vec<_> = server.rx.iter().take(2).collect();
+    assert_eq!(requests.len(), 2);
+    assert!(
+        started.elapsed() < Duration::from_millis(700),
+        "ignored datagrams restarted an attempt deadline"
+    );
+    server.join();
+}
+
+#[test]
+fn opening_deadline_overflow_occurs_before_send() {
+    let server = timeout_server(Duration::from_millis(250));
+    let config = ClientConfig {
+        open_timeouts: vec![Duration::MAX],
+        ..default_test_config(server.addr)
+    };
+    let mut client = Client::connect(config).unwrap();
+
+    assert!(matches!(client.open(), Err(ClientError::DurationOverflow)));
+    assert!(server.rx.try_recv().is_err());
+    server.join();
+}
+
+#[test]
+fn post_token_negotiation_failure_sends_cleanup_close() {
+    let mut returned = default_params();
+    returned.interval_ns += 1;
+    let server = start_fake_server(move |socket, tx| {
+        let (_, peer) = recv_request(&socket, &tx);
+        socket
+            .send_to(
+                &open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &returned, None),
+                peer,
+            )
+            .unwrap();
+        let _ = recv_request(&socket, &tx);
+    });
+    let mut client = Client::connect(default_test_config(server.addr)).unwrap();
+
+    assert!(matches!(
+        client.open(),
+        Err(ClientError::NegotiationRejected { .. })
+    ));
+    let packets: Vec<_> = server.rx.iter().take(2).collect();
+    assert_eq!(packets[1][3], flags::FLAG_CLOSE);
+    assert_eq!(
+        u64::from_le_bytes(packets[1][4..12].try_into().unwrap()),
+        TOKEN
+    );
+    server.join();
+}
+
+#[test]
+fn open_timeout_after_all_timeouts() {
+    let server = timeout_server(Duration::from_millis(700));
+    let config = ClientConfig {
+        open_timeouts: vec![Duration::from_millis(200), Duration::from_millis(200)],
+        socket_config: irtt_client::SocketConfig {
+            recv_timeout: Some(Duration::from_millis(50)),
+            ..Default::default()
+        },
+        ..default_test_config(server.addr)
+    };
+    let mut client = Client::connect(config).unwrap();
+    assert!(matches!(client.open(), Err(ClientError::OpenTimeout)));
+    assert_eq!(server.rx.iter().take(2).count(), 2);
+    server.join();
+}
+
+#[test]
+fn multiple_untrusted_datagrams_before_valid_reply_use_one_attempt() {
+    let params = default_params();
+    let server = start_fake_server(move |socket, tx| {
+        let (_, peer) = recv_request(&socket, &tx);
+        let valid = open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, None);
+        let mut wrong_type = valid.clone();
+        wrong_type[3] = FLAG_REPLY;
+        let mut reserved_flags = valid.clone();
+        reserved_flags[3] |= 0x10;
+        let mut bad_magic = valid.clone();
+        bad_magic[0] ^= 0xff;
+        let unexpected_hmac =
+            open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, Some(b"unexpected"));
+
+        for packet in [
+            vec![0_u8],
+            bad_magic,
+            wrong_type,
+            reserved_flags,
+            unexpected_hmac,
+            valid,
+        ] {
+            socket.send_to(&packet, peer).unwrap();
+        }
+    });
+    let mut client = Client::connect(default_test_config(server.addr)).unwrap();
+
+    assert_open_started(client.open().unwrap());
+    assert_eq!(server.rx.iter().take(1).count(), 1);
+    assert!(server.rx.try_recv().is_err());
+
+    server.join();
+}
+
+#[test]
+fn only_ignored_open_datagrams_eventually_time_out() {
+    let server = start_fake_server(move |socket, tx| {
+        for _ in 0..2 {
+            let (_, peer) = recv_request(&socket, &tx);
+            socket.send_to(&[0_u8], peer).unwrap();
+            socket.send_to(&MAGIC, peer).unwrap();
+        }
+        thread::sleep(Duration::from_millis(300));
+    });
+    let config = ClientConfig {
+        open_timeouts: vec![Duration::from_millis(200), Duration::from_millis(200)],
+        socket_config: irtt_client::SocketConfig {
+            recv_timeout: Some(Duration::from_millis(50)),
+            ..Default::default()
+        },
+        ..default_test_config(server.addr)
+    };
+    let mut client = Client::connect(config).unwrap();
+
+    assert!(matches!(client.open(), Err(ClientError::OpenTimeout)));
+    assert_eq!(server.rx.iter().take(2).count(), 2);
+    assert!(server.rx.try_recv().is_err());
+    server.join();
+}
+
+#[test]
+fn trusted_zero_token_normal_reply_is_terminal() {
+    let params = default_params();
+    let server = start_fake_server(move |socket, tx| {
+        let (_, peer) = recv_request(&socket, &tx);
+        // encode_open_reply rejects a zero token without FLAG_CLOSE, so this
+        // deliberately non-compliant reply is built by encoding a normal
+        // reply with a placeholder token and then zeroing the token field.
+        let mut reply = open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, None);
+        reply[HMAC_OFFSET..HMAC_OFFSET + 8].copy_from_slice(&0_u64.to_le_bytes());
+        socket.send_to(&reply, peer).unwrap();
+    });
+    let mut client = Client::connect(default_test_config(server.addr)).unwrap();
+
+    assert!(matches!(
+        client.open(),
+        Err(ClientError::Protocol(irtt_proto::ProtoError::ZeroToken))
+    ));
+    assert_eq!(server.rx.iter().take(1).count(), 1);
+
+    server.join();
+}

crates/irtt-client/tests/client/probes_replies/mod.rs

@@ -2,7 +2,7 @@ use super::*;
 use support::echo_packet_len;
 
 #[cfg(not(all(target_os = "linux", feature = "ancillary")))]
-fn assert_packet_meta_unavailable(packet_meta: &crate::event::PacketMeta) {
+fn assert_packet_meta_unavailable(packet_meta: &irtt_client::PacketMeta) {
     assert_eq!(packet_meta.traffic_class, None);
     assert_eq!(packet_meta.dscp, None);
     assert_eq!(packet_meta.ecn, None);
@@ -20,11 +20,8 @@ fn kernel_rx_timestamp_unavailable_skip(test_name: &str) {
 }
 
 mod burst_recv;
-mod interrupted_receive;
 mod packet_length;
-mod probe_schedule;
 mod reply_classification;
 mod reply_decode;
 mod reply_metadata;
 mod timeouts;
-mod timing_math;

crates/irtt-client/tests/client/probes_replies/packet_length.rs

@@ -1,62 +1,5 @@
 use super::*;
 
-#[test]
-fn minimal_negotiated_layout_works() {
-    let params = Params {
-        protocol_version: 1,
-        duration_ns: 3_000_000_000,
-        interval_ns: 1_000_000_000,
-        received_stats: ReceivedStats::None,
-        stamp_at: StampAt::None,
-        clock: Clock::Both,
-        ..Params::default()
-    };
-    let server = start_fake_server(move |socket, tx| {
-        let (_, peer) = recv_request(&socket, &tx);
-        let reply = open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, None);
-        socket.send_to(&reply, peer).unwrap();
-
-        socket
-            .set_read_timeout(Some(Duration::from_secs(2)))
-            .unwrap();
-        let mut buf = [0_u8; 2048];
-        if let Ok((size, _)) = socket.recv_from(&mut buf) {
-            tx.send(buf[..size].to_vec()).unwrap();
-            let seq = u32::from_le_bytes(buf[12..16].try_into().unwrap());
-            let ts = TimestampFields::default();
-            let reply_packet = echo_reply_packet(TOKEN, seq, &params, &ts, None);
-            socket.send_to(&reply_packet, peer).unwrap();
-        }
-    });
-    let config = ClientConfig {
-        received_stats: ReceivedStats::None,
-        stamp_at: StampAt::None,
-        socket_config: crate::SocketConfig {
-            recv_timeout: Some(Duration::from_millis(200)),
-            ..Default::default()
-        },
-        ..default_test_config(server.addr)
-    };
-    let mut client = Client::connect(config).unwrap();
-    assert_open_started(client.open().unwrap());
-    client.send_probe().unwrap();
-    thread::sleep(Duration::from_millis(30));
-    let events = client.recv_once().unwrap();
-    assert_eq!(events.len(), 1);
-    if let ClientEvent::EchoReply {
-        received_stats,
-        server_timing,
-        ..
-    } = &events[0]
-    {
-        assert!(received_stats.is_none());
-        assert!(server_timing.is_none());
-    } else {
-        panic!("expected EchoReply");
-    }
-    server.join();
-}
-
 // ---------- Regression tests ----------
 
 #[test]
@@ -81,7 +24,7 @@ fn short_echo_reply_does_not_emit_echo_reply() {
     });
     let config = ClientConfig {
         length: 64,
-        socket_config: crate::SocketConfig {
+        socket_config: irtt_client::SocketConfig {
             recv_timeout: Some(Duration::from_millis(200)),
             ..Default::default()
         },
@@ -127,7 +70,7 @@ fn overlong_datagram_detection_uses_extra_receive_byte() {
     });
     let config = ClientConfig {
         length: 4096,
-        socket_config: crate::SocketConfig {
+        socket_config: irtt_client::SocketConfig {
             recv_timeout: Some(Duration::from_millis(200)),
             ..Default::default()
         },
@@ -170,7 +113,7 @@ fn exact_length_echo_reply_still_emits_echo_reply() {
     });
     let config = ClientConfig {
         length: 4096,
-        socket_config: crate::SocketConfig {
+        socket_config: irtt_client::SocketConfig {
             recv_timeout: Some(Duration::from_millis(200)),
             ..Default::default()
         },

crates/irtt-client/tests/client/probes_replies/reply_classification.rs

@@ -23,7 +23,7 @@ fn duplicate_reply_emits_duplicate_event() {
         }
     });
     let config = ClientConfig {
-        socket_config: crate::SocketConfig {
+        socket_config: irtt_client::SocketConfig {
             recv_timeout: Some(Duration::from_millis(200)),
             ..Default::default()
         },
@@ -77,7 +77,7 @@ fn out_of_order_reply_emits_late_event() {
         socket.send_to(&reply0, peer).unwrap();
     });
     let config = ClientConfig {
-        socket_config: crate::SocketConfig {
+        socket_config: irtt_client::SocketConfig {
             recv_timeout: Some(Duration::from_millis(200)),
             ..Default::default()
         },

crates/irtt-client/tests/client/probes_replies/reply_decode.rs

@@ -5,7 +5,7 @@ fn recv_once_returns_empty_on_timeout() {
     let params = default_params();
     let server = open_success_server(params);
     let config = ClientConfig {
-        socket_config: crate::SocketConfig {
+        socket_config: irtt_client::SocketConfig {
             recv_timeout: Some(Duration::from_millis(50)),
             ..Default::default()
         },
@@ -18,66 +18,6 @@ fn recv_once_returns_empty_on_timeout() {
     server.join();
 }
 
-#[test]
-fn recv_once_decodes_echo_reply_and_emits_event() {
-    let params = default_params();
-    let (mut client, server) = open_client_with_echo_server(&params);
-
-    client.send_probe().unwrap();
-    thread::sleep(Duration::from_millis(50));
-
-    let events = client.recv_once().unwrap();
-    assert_eq!(events.len(), 1);
-    match &events[0] {
-        ClientEvent::EchoReply {
-            seq,
-            rtt,
-            received_stats,
-            server_timing,
-            bytes,
-            packet_meta,
-            ..
-        } => {
-            assert_eq!(*seq, 0);
-            assert_eq!(*bytes, echo_packet_len(false, &params));
-            assert!(rtt.raw > Duration::ZERO);
-            assert_eq!(
-                rtt.effective,
-                rtt.adjusted
-                    .unwrap_or_else(|| SignedDuration::from_duration(rtt.raw))
-            );
-            assert!(received_stats.is_some());
-            let stats = received_stats.as_ref().unwrap();
-            assert_eq!(stats.count, Some(42));
-            assert_eq!(stats.window, Some(0x07));
-            assert!(server_timing.is_some());
-            let st = server_timing.as_ref().unwrap();
-            assert!(st.processing.is_some());
-            #[cfg(not(all(target_os = "linux", feature = "ancillary")))]
-            {
-                assert_eq!(packet_meta.traffic_class, None);
-                assert_eq!(packet_meta.dscp, None);
-                assert_eq!(packet_meta.ecn, None);
-                assert_eq!(packet_meta.kernel_rx_timestamp, None);
-            }
-            #[cfg(all(target_os = "linux", feature = "ancillary"))]
-            {
-                assert_eq!(
-                    packet_meta.dscp,
-                    packet_meta.traffic_class.map(|tc| tc >> 2)
-                );
-                assert_eq!(
-                    packet_meta.ecn,
-                    packet_meta.traffic_class.map(|tc| tc & 0b11)
-                );
-            }
-        }
-        other => panic!("expected EchoReply, got {other:?}"),
-    }
-    client.close().unwrap();
-    server.join();
-}
-
 #[test]
 fn recv_once_decodes_only_received_bytes_after_longer_datagram() {
     let params = default_params();
@@ -113,7 +53,7 @@ fn recv_once_decodes_only_received_bytes_after_longer_datagram() {
         socket.send_to(&shorter, peer).unwrap();
     });
     let config = ClientConfig {
-        socket_config: crate::SocketConfig {
+        socket_config: irtt_client::SocketConfig {
             recv_timeout: Some(Duration::from_millis(200)),
             ..Default::default()
         },

crates/irtt-client/tests/client/probes_replies/reply_metadata.rs

@@ -14,13 +14,13 @@ fn echo_reply_metadata_propagates_observed_dscp_with_ancillary() {
         let (size, _) = socket.recv_from(&mut buf).unwrap();
         tx.send(buf[..size].to_vec()).unwrap();
         let seq = u32::from_le_bytes(buf[12..16].try_into().unwrap());
-        crate::socket_options::apply_traffic_class_to_socket(&socket, peer, 184).unwrap();
+        socket2::SockRef::from(&socket).set_tos_v4(184).unwrap();
         let reply_packet =
             echo_reply_packet(TOKEN, seq, &params, &TimestampFields::default(), None);
         socket.send_to(&reply_packet, peer).unwrap();
     });
     let config = ClientConfig {
-        socket_config: crate::SocketConfig {
+        socket_config: irtt_client::SocketConfig {
             recv_timeout: Some(Duration::from_millis(200)),
             ..Default::default()
         },

crates/irtt-client/tests/client/probes_replies/timeouts.rs

@@ -1,12 +1,52 @@
 use super::*;
 
+#[test]
+fn probe_timeout_overflow_transmits_no_echo() {
+    let params = default_params();
+    let server = start_fake_server(move |socket, tx| {
+        socket
+            .set_read_timeout(Some(Duration::from_secs(2)))
+            .unwrap();
+        let (_, peer) = recv_request(&socket, &tx);
+        socket
+            .send_to(
+                &open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params, None),
+                peer,
+            )
+            .unwrap();
+        // CLOSE is a completion barrier: any incorrectly transmitted ECHO
+        // precedes it on this connected loopback socket.
+        let _ = recv_request(&socket, &tx);
+    });
+    let config = ClientConfig {
+        probe_timeout: Duration::MAX,
+        ..default_test_config(server.addr)
+    };
+    let mut client = Client::connect(config).unwrap();
+    assert_open_started(client.open().unwrap());
+    assert!(matches!(
+        client.send_probe(),
+        Err(ClientError::DurationOverflow)
+    ));
+    assert!(!client.has_pending_probes());
+    client.close().unwrap();
+    let packets: Vec<_> = server.rx.iter().collect();
+    assert_eq!(packets.len(), 2);
+    assert_eq!(
+        packets[1][3],
+        flags::FLAG_CLOSE,
+        "overflow must not transmit an ECHO"
+    );
+    server.join();
+}
+
 #[test]
 fn poll_timeouts_emits_echo_loss() {
     let params = default_params();
     let server = silent_open_server(params);
     let config = ClientConfig {
         probe_timeout: Duration::from_millis(100),
-        socket_config: crate::SocketConfig {
+        socket_config: irtt_client::SocketConfig {
             recv_timeout: Some(Duration::from_millis(50)),
             ..Default::default()
         },
@@ -57,7 +97,7 @@ fn late_reply_after_timeout_preserves_measurement_metadata() {
     });
     let config = ClientConfig {
         probe_timeout: Duration::from_millis(40),
-        socket_config: crate::SocketConfig {
+        socket_config: irtt_client::SocketConfig {
             recv_timeout: Some(Duration::from_millis(200)),
             ..Default::default()
         },
@@ -119,7 +159,7 @@ fn pending_full_does_not_send_packet() {
     let config = ClientConfig {
         duration: Some(Duration::from_secs(60)),
         max_pending_probes: 2,
-        socket_config: crate::SocketConfig {
+        socket_config: irtt_client::SocketConfig {
             recv_timeout: Some(Duration::from_millis(50)),
             ..Default::default()
         },

crates/irtt-client/tests/client/support.rs

@@ -253,7 +253,7 @@ pub(super) fn assert_no_test_completed(outcome: OpenOutcome) -> NegotiatedParams
 pub(super) fn open_client_with_echo_server(params: &Params) -> (Client, FakeServer) {
     let server = echo_server(params.clone());
     let config = ClientConfig {
-        socket_config: crate::SocketConfig {
+        socket_config: irtt_client::SocketConfig {
             recv_timeout: Some(Duration::from_millis(200)),
             ..Default::default()
         },

crates/irtt-client/tests/client/ttl.rs

@@ -0,0 +1,22 @@
+use super::*;
+
+#[test]
+fn connect_accepts_valid_ttl_config_values() {
+    for ttl in [None, Some(1), Some(255)] {
+        let mut config = default_test_config(SocketAddr::from(([127, 0, 0, 1], 9)));
+        config.socket_config.ttl = ttl;
+        Client::connect(config).unwrap();
+    }
+}
+
+#[test]
+fn connect_rejects_invalid_ttl_values() {
+    for ttl in [0, 256] {
+        let mut config = default_test_config(SocketAddr::from(([127, 0, 0, 1], 9)));
+        config.socket_config.ttl = Some(ttl);
+        assert!(matches!(
+            Client::connect(config),
+            Err(ClientError::InvalidConfig { .. })
+        ));
+    }
+}

crates/irtt-client/tests/linux_transport.rs

@@ -0,0 +1,259 @@
+//! Real Linux socket observations through the public client adapters.
+#![cfg(all(target_os = "linux", feature = "ancillary"))]
+
+use std::{
+    io::IoSliceMut,
+    net::{SocketAddr, UdpSocket},
+    sync::mpsc,
+    thread,
+    time::{Duration, SystemTime, UNIX_EPOCH},
+};
+
+use irtt_client::{Client, ClientConfig, ClientEvent, NegotiationPolicy, SocketConfig};
+use irtt_proto::{decode_request, Clock, DecodedRequestKind, ReceivedStats, StampAt};
+use irtt_server::{ServerConfig, ServerCore};
+use nix::sys::socket::{recvmsg, ControlMessageOwned, MsgFlags};
+
+const TEST_TTL: u32 = 37;
+
+// A compliant packet peer uses the real server core. Its receive-side IP_TOS
+// observation is independent of the client/server parameter agreement.
+fn peer(dscp_allowed: bool, probes: usize) -> (SocketAddr, thread::JoinHandle<Vec<u8>>) {
+    let socket = UdpSocket::bind("127.0.0.1:0").unwrap();
+    socket
+        .set_read_timeout(Some(Duration::from_secs(3)))
+        .unwrap();
+    socket2::SockRef::from(&socket)
+        .set_recv_tos_v4(true)
+        .unwrap();
+    nix::sys::socket::setsockopt(&socket, nix::sys::socket::sockopt::Ipv4RecvTtl, &true).unwrap();
+    let addr = socket.local_addr().unwrap();
+    let task = thread::spawn(move || {
+        let mut core = ServerCore::new(
+            ServerConfig::default()
+                .with_min_send_interval(Duration::ZERO)
+                .with_dscp_allowed(dscp_allowed),
+        );
+        let mut markings = Vec::new();
+        // OPEN, every ECHO, then CLOSE.
+        for _ in 0..probes + 2 {
+            let mut bytes = [0; 2048];
+            let mut control = nix::cmsg_space!(u8, i32);
+            let mut iov = [IoSliceMut::new(&mut bytes)];
+            let msg = recvmsg::<nix::sys::socket::SockaddrIn>(
+                std::os::fd::AsRawFd::as_raw_fd(&socket),
+                &mut iov,
+                Some(&mut control),
+                MsgFlags::empty(),
+            )
+            .unwrap();
+            let size = msg.bytes;
+            let source = msg.address.unwrap();
+            let marking = msg
+                .cmsgs()
+                .unwrap()
+                .find_map(|message| match message {
+                    ControlMessageOwned::Ipv4Tos(tos) => Some(tos),
+                    _ => None,
+                })
+                .expect("Linux must report IP_TOS");
+            let ttl = msg
+                .cmsgs()
+                .unwrap()
+                .find_map(|message| match message {
+                    ControlMessageOwned::Ipv4Ttl(ttl) => Some(ttl),
+                    _ => None,
+                })
+                .expect("Linux must report IP_TTL");
+            assert_eq!(
+                ttl, TEST_TTL as i32,
+                "configured TTL must survive OPEN, ECHO and CLOSE"
+            );
+            markings.push(marking);
+            let source = SocketAddr::from((source.ip(), source.port()));
+            if let Some(reply) = core.handle_datagram(source, &bytes[..size]).unwrap() {
+                socket.send_to(reply.bytes(), source).unwrap();
+            }
+        }
+        assert_eq!(core.session_count(), 0);
+        markings
+    });
+    (addr, task)
+}
+
+fn config(addr: SocketAddr) -> ClientConfig {
+    ClientConfig {
+        server_addr: addr.to_string(),
+        dscp: 46,
+        negotiation_policy: NegotiationPolicy::Loose,
+        duration: None,
+        interval: Duration::from_millis(10),
+        clock: Clock::Both,
+        stamp_at: StampAt::Both,
+        received_stats: ReceivedStats::Both,
+        length: 128,
+        open_timeouts: vec![Duration::from_secs(1)],
+        socket_config: SocketConfig {
+            ttl: Some(TEST_TTL),
+            recv_timeout: Some(Duration::from_secs(1)),
+            ..SocketConfig::default()
+        },
+        ..ClientConfig::default()
+    }
+}
+
+// TX timestamps have no separate public field: the upstream OWD exposes the
+// selected send endpoint. Reconstruct it and require a real kernel endpoint
+// rather than accepting the userspace fallback. RTT must still use sent_at.
+fn assert_kernel_send_endpoint(event: &ClientEvent, before_send: SystemTime) {
+    let ClientEvent::EchoReply {
+        sent_at,
+        received_at,
+        rtt,
+        server_timing: Some(timing),
+        one_way: Some(one_way),
+        packet_meta,
+        ..
+    } = event
+    else {
+        panic!("expected measured reply: {event:?}")
+    };
+    let ns = |wall: SystemTime| {
+        i128::try_from(wall.duration_since(UNIX_EPOCH).unwrap().as_nanos()).unwrap()
+    };
+    let selected =
+        i128::from(timing.receive_wall_ns.unwrap()) - one_way.client_to_server.unwrap().as_nanos();
+    assert!(selected >= ns(before_send));
+    // TX_SOFTWARE may arrive before or after send returns; only equality
+    // identifies the userspace fallback. Receipt remains the upper bound.
+    assert_ne!(
+        selected,
+        ns(sent_at.wall),
+        "TX timestamp was not observed; userspace fallback is insufficient"
+    );
+    assert!(selected <= ns(received_at.wall));
+    let selected_receive =
+        i128::from(timing.send_wall_ns.unwrap()) + one_way.server_to_client.unwrap().as_nanos();
+    assert_eq!(
+        selected_receive,
+        ns(packet_meta
+            .kernel_rx_timestamp
+            .expect("Linux RX timestamp required")),
+        "downstream OWD must use the kernel receive endpoint"
+    );
+    assert_eq!(rtt.raw, received_at.mono.duration_since(sent_at.mono));
+}
+
+#[test]
+fn blocking_probes_use_kernel_tx_timing_and_negotiated_packet_marking() {
+    for allowed in [true, false] {
+        const PROBES: usize = 3;
+        let (addr, peer) = peer(allowed, PROBES);
+        let mut client = Client::connect(config(addr)).unwrap();
+        client.open().unwrap();
+        assert_eq!(
+            client.negotiated_params().unwrap().params.dscp,
+            if allowed { 184 } else { 0 }
+        );
+        for _ in 0..PROBES {
+            let before = SystemTime::now();
+            client.send_probe().unwrap();
+            let events = client.recv_once().unwrap();
+            assert_eq!(events.len(), 1);
+            assert_kernel_send_endpoint(&events[0], before);
+        }
+        client.close().unwrap();
+        let markings = peer.join().unwrap();
+        assert_eq!(markings[0], 0, "OPEN is unmarked");
+        assert_eq!(
+            &markings[1..=PROBES],
+            vec![if allowed { 184 } else { 0 }; PROBES]
+        );
+        assert_eq!(
+            markings[PROBES + 1],
+            0,
+            "local CLOSE clears the negotiated marking"
+        );
+    }
+}
+
+#[cfg(feature = "tokio")]
+#[test]
+fn async_probes_use_kernel_tx_timing_and_negotiated_packet_marking() {
+    let runtime = tokio::runtime::Builder::new_current_thread()
+        .enable_all()
+        .build()
+        .unwrap();
+    for allowed in [true, false] {
+        const PROBES: usize = 3;
+        let (addr, peer) = peer(allowed, PROBES);
+        runtime.block_on(async {
+            tokio::time::timeout(Duration::from_secs(5), async {
+                let mut client = irtt_client::AsyncClient::connect(config(addr))
+                    .await
+                    .unwrap();
+                client.open().await.unwrap();
+                assert_eq!(
+                    client.negotiated_params().unwrap().params.dscp,
+                    if allowed { 184 } else { 0 }
+                );
+                for _ in 0..PROBES {
+                    let before = SystemTime::now();
+                    client.send_probe().await.unwrap();
+                    let events = client.recv().await.unwrap();
+                    assert_eq!(events.len(), 1);
+                    assert_kernel_send_endpoint(&events[0], before);
+                }
+                client.close().await.unwrap();
+            })
+            .await
+            .expect("async transport observations timed out");
+        });
+        let markings = peer.join().unwrap();
+        assert_eq!(markings[0], 0);
+        assert_eq!(
+            &markings[1..=PROBES],
+            vec![if allowed { 184 } else { 0 }; PROBES]
+        );
+        assert_eq!(markings[PROBES + 1], 0);
+    }
+}
+
+// Real ICMP refusal remains a socket error, never optional timestamp metadata.
+// The bound peer closes only after the client has accepted a valid OPEN.
+#[test]
+fn a_closed_udp_peer_surfaces_a_socket_error() {
+    let socket = UdpSocket::bind("127.0.0.1:0").unwrap();
+    let addr = socket.local_addr().unwrap();
+    socket
+        .set_read_timeout(Some(Duration::from_secs(3)))
+        .unwrap();
+    let (close_tx, close_rx) = mpsc::channel();
+    let task = thread::spawn(move || {
+        let mut core = ServerCore::new(ServerConfig::default());
+        let mut bytes = [0; 2048];
+        let (size, source) = socket.recv_from(&mut bytes).unwrap();
+        assert!(matches!(
+            decode_request(&bytes[..size]).unwrap().kind,
+            DecodedRequestKind::Open { .. }
+        ));
+        let reply = core
+            .handle_datagram(source, &bytes[..size])
+            .unwrap()
+            .unwrap();
+        socket.send_to(reply.bytes(), source).unwrap();
+        close_rx.recv_timeout(Duration::from_secs(3)).unwrap();
+        drop(socket);
+    });
+    let mut client = Client::connect(config(addr)).unwrap();
+    client.open().unwrap();
+    close_tx.send(()).unwrap();
+    task.join().unwrap();
+    // Refusal can arrive during send's TX drain or the following receive.
+    let result = client.send_probe().and_then(|_| client.recv_once());
+    assert!(
+        matches!(result, Err(irtt_client::ClientError::Socket(ref error))
+        if error.kind() == std::io::ErrorKind::ConnectionRefused),
+        "{result:?}"
+    );
+}

crates/irtt-client/tests/managed_control.rs

@@ -0,0 +1,160 @@
+#![cfg(feature = "tokio")]
+
+use std::{
+    future::Future,
+    pin::pin,
+    task::{Context, Poll, Waker},
+    time::Duration,
+};
+
+use irtt_client::managed::*;
+
+fn config() -> ManagedClientConfig {
+    ManagedClientConfig {
+        completion: ManagedCompletionPolicy::ExplicitStop,
+        command_capacity: 3,
+        ..ManagedClientConfig::default()
+    }
+}
+
+#[test]
+fn stop_resolves_every_accepted_update_and_closes_admission() {
+    let (task, handle) = ManagedClient::task(config(), vec![]).unwrap();
+    let receipts: Vec<_> = (0..3)
+        .map(|index| {
+            handle
+                .update_targets(vec![ManagedTargetConfig::new(
+                    format!("queued-{index}"),
+                    "127.0.0.1:9",
+                )])
+                .unwrap()
+        })
+        .collect();
+    assert!(matches!(
+        handle.update_targets(vec![]),
+        Err(ManagedCommandError::QueueFull)
+    ));
+
+    let stop = handle.stop();
+    assert!(matches!(
+        handle.update_targets(vec![]),
+        Err(ManagedCommandError::Stopping)
+    ));
+    let runtime = tokio::runtime::Builder::new_current_thread()
+        .enable_all()
+        .build()
+        .unwrap();
+    runtime.block_on(async {
+        tokio::time::timeout(Duration::from_secs(2), async {
+            let outcome = task.await;
+            stop.await;
+            for receipt in receipts {
+                assert!(matches!(
+                    receipt.await,
+                    Err(ManagedCommandApplyError::Stopping)
+                ));
+            }
+            assert_eq!(outcome.end_reason, ManagedEndReason::StopRequested);
+            assert_eq!(outcome.applied_command_sequence, 0);
+            assert_eq!(outcome.total_target_outcomes, 0);
+            let status = handle.status();
+            assert_eq!(status.lifecycle, ManagedLifecycle::Completed);
+            assert!(status.stop_requested);
+            assert_eq!(status.final_outcome.as_deref(), Some(&outcome));
+            assert!(matches!(
+                handle.update_targets(vec![]),
+                Err(ManagedCommandError::DriverClosed)
+            ));
+            handle.stop().await;
+        })
+        .await
+        .expect("stop must resolve every buffered update and repeated stop receipt");
+    });
+}
+
+#[test]
+fn failed_driver_resolves_every_accepted_update_with_its_terminal_failure() {
+    let (task, handle) = ManagedClient::task(config(), vec![]).unwrap();
+    let receipts: Vec<_> = (0..3)
+        .map(|index| {
+            handle
+                .update_targets(vec![ManagedTargetConfig::new(
+                    format!("queued-{index}"),
+                    "127.0.0.1:9",
+                )])
+                .unwrap()
+        })
+        .collect();
+    let mut context = Context::from_waker(Waker::noop());
+    let Poll::Ready(outcome) = pin!(task).as_mut().poll(&mut context) else {
+        panic!("polling without Tokio must fail immediately");
+    };
+    assert_eq!(
+        outcome.end_reason,
+        ManagedEndReason::DriverFailed(ManagedDriverFailure::NoTokioRuntime)
+    );
+    for receipt in receipts {
+        assert!(matches!(
+            pin!(receipt).as_mut().poll(&mut context),
+            Poll::Ready(Err(ManagedCommandApplyError::DriverFailed(
+                ManagedDriverFailure::NoTokioRuntime
+            )))
+        ));
+    }
+    let status = handle.status();
+    assert_eq!(status.lifecycle, ManagedLifecycle::Failed);
+    assert_eq!(status.final_outcome.as_deref(), Some(&outcome));
+    assert!(matches!(
+        handle.update_targets(vec![]),
+        Err(ManagedCommandError::DriverClosed)
+    ));
+    assert!(pin!(handle.stop()).as_mut().poll(&mut context).is_ready());
+}
+
+#[test]
+fn concurrent_submission_and_stop_or_seal_never_lose_an_accepted_receipt() {
+    let (task, handle) = ManagedClient::task(config(), vec![]).unwrap();
+    let barrier = std::sync::Arc::new(std::sync::Barrier::new(2));
+    let submit_barrier = std::sync::Arc::clone(&barrier);
+    let submit_handle = handle.clone();
+    let (sender, receiver) = std::sync::mpsc::channel();
+    let submit = std::thread::spawn(move || {
+        submit_barrier.wait();
+        sender.send(submit_handle.update_targets(vec![])).unwrap();
+    });
+    let runtime = tokio::runtime::Builder::new_current_thread()
+        .enable_all()
+        .build()
+        .unwrap();
+    // Stop is latched before the driver starts, while submission may cross
+    // admission before stop, after stop, or after terminal sealing.
+    barrier.wait();
+    let stop = handle.stop();
+    runtime.block_on(async {
+        tokio::time::timeout(Duration::from_secs(2), async {
+            let outcome = task.await;
+            stop.await;
+            assert_eq!(outcome.end_reason, ManagedEndReason::StopRequested);
+            assert_eq!(outcome.applied_command_sequence, 0);
+            assert_eq!(outcome.total_target_outcomes, 0);
+            let result = receiver
+                .recv_timeout(Duration::from_secs(2))
+                .expect("concurrent submission must return");
+            submit.join().unwrap();
+            match result {
+                Ok(receipt) => assert!(matches!(
+                    receipt.await,
+                    Err(ManagedCommandApplyError::Stopping)
+                )),
+                Err(ManagedCommandError::Stopping | ManagedCommandError::DriverClosed) => {}
+                Err(error) => panic!("unexpected concurrent submission result: {error:?}"),
+            }
+            assert!(matches!(
+                handle.update_targets(vec![]),
+                Err(ManagedCommandError::DriverClosed)
+            ));
+        })
+        .await
+        .expect("every accepted concurrent submission must receive a terminal disposition");
+    });
+}

crates/irtt-integration-tests/tests/async_client.rs

@@ -75,16 +75,48 @@ async fn exercise_client_server() {
             ..
         }] if *remote == server_addr
     ));
-    assert!(matches!(
-        client.recv().await.unwrap().as_slice(),
-        [ClientEvent::EchoReply {
-            seq: 0,
-            remote,
-            server_timing: Some(_),
-            received_stats: Some(_),
-            ..
-        }] if *remote == server_addr
-    ));
+    let events = client.recv().await.unwrap();
+    let [ClientEvent::EchoReply {
+        seq: 0,
+        remote,
+        sent_at,
+        received_at,
+        rtt,
+        server_timing: Some(timing),
+        one_way: Some(one_way),
+        received_stats: Some(_),
+        packet_meta,
+        ..
+    }] = events.as_slice()
+    else {
+        panic!("expected a measured reply, got {events:?}");
+    };
+    assert_eq!(*remote, server_addr);
+    assert_eq!(rtt.raw, received_at.mono.duration_since(sent_at.mono));
+    // Verify the measurement endpoint through public reply metadata and real
+    // OS timestamps. This also covers the userspace fallback on other targets.
+    let receive_wall = packet_meta
+        .kernel_rx_timestamp
+        .filter(|kernel| {
+            received_at
+                .wall
+                .duration_since(*kernel)
+                .is_ok_and(|lag| lag <= Duration::from_secs(1))
+        })
+        .unwrap_or(received_at.wall);
+    let receive_ns = i128::try_from(
+        receive_wall
+            .duration_since(std::time::UNIX_EPOCH)
+            .unwrap()
+            .as_nanos(),
+    )
+    .unwrap();
+    assert_eq!(
+        one_way.server_to_client,
+        Some(irtt_client::SignedDuration::from_nanos(
+            receive_ns - i128::from(timing.send_wall_ns.unwrap())
+        ))
+    );
     assert!(matches!(
         client.close().await.unwrap().as_slice(),
         [ClientEvent::SessionClosed { remote, .. }] if *remote == server_addr

crates/irtt-integration-tests/tests/async_client_lifecycle.rs

@@ -0,0 +1,678 @@
+use std::{
+    future::Future,
+    net::UdpSocket,
+    pin::Pin,
+    sync::mpsc,
+    task::{Context, Poll, Waker},
+    thread::{self, JoinHandle},
+};
+
+use irtt_proto::{
+    decode_request, encode_echo_reply, encode_open_reply, flags, verify_packet_hmac,
+    DecodedRequestKind, EchoReply, OpenReply, Params, ReceivedStats, StampAt, TimestampFields,
+};
+use tokio::runtime::{Builder, Runtime};
+
+mod support;
+
+use irtt_client::{AsyncClient, ClientConfig, ClientError, ClientEvent, OpenOutcome};
+use irtt_client::{Client, RunMode, SocketConfig};
+use irtt_server::ServerConfig;
+use std::{
+    io,
+    net::SocketAddr,
+    time::{Duration, Instant},
+};
+use support::InTreeServer;
+
+const TOKEN: u64 = 0x1234_5678_90ab_cdef;
+
+struct TestServer {
+    addr: SocketAddr,
+    packets: mpsc::Receiver<Vec<u8>>,
+    done: JoinHandle<()>,
+}
+
+impl TestServer {
+    fn finish(self) -> Vec<Vec<u8>> {
+        self.done.join().unwrap();
+        self.packets.try_iter().collect()
+    }
+}
+
+fn runtime() -> Runtime {
+    Builder::new_current_thread()
+        .enable_io()
+        .enable_time()
+        .build()
+        .unwrap()
+}
+
+fn config(addr: SocketAddr, key: Option<Vec<u8>>, dscp: u8) -> ClientConfig {
+    ClientConfig {
+        server_addr: addr.to_string(),
+        received_stats: ReceivedStats::None,
+        stamp_at: StampAt::None,
+        dscp,
+        hmac_key: key,
+        open_timeouts: vec![Duration::from_millis(200)],
+        socket_config: SocketConfig {
+            recv_timeout: Some(Duration::from_millis(200)),
+            ..SocketConfig::default()
+        },
+        ..ClientConfig::default()
+    }
+}
+
+async fn opened_client(addr: SocketAddr, dscp: u8) -> AsyncClient {
+    let mut client = AsyncClient::connect(config(addr, None, dscp))
+        .await
+        .unwrap();
+    client.open().await.unwrap();
+    client
+}
+
+fn start_server<F>(handler: F) -> TestServer
+where
+    F: FnOnce(UdpSocket, mpsc::Sender<Vec<u8>>) + Send + 'static,
+{
+    let socket = UdpSocket::bind("127.0.0.1:0").unwrap();
+    socket
+        .set_read_timeout(Some(Duration::from_secs(2)))
+        .unwrap();
+    let addr = socket.local_addr().unwrap();
+    let (tx, packets) = mpsc::channel();
+    let done = thread::spawn(move || handler(socket, tx));
+    TestServer {
+        addr,
+        packets,
+        done,
+    }
+}
+
+fn recv_packet(socket: &UdpSocket, tx: &mpsc::Sender<Vec<u8>>) -> (Vec<u8>, SocketAddr) {
+    let mut buffer = [0_u8; 8192];
+    let (len, peer) = socket.recv_from(&mut buffer).unwrap();
+    let packet = buffer[..len].to_vec();
+    tx.send(packet.clone()).unwrap();
+    (packet, peer)
+}
+
+/// Admits a request the way a compliant server does: structural decode first,
+/// then HMAC presence policy, then authentication. Returns `None` for anything
+/// a server would silently discard.
+fn decode_server_request<'a>(
+    packet: &'a [u8],
+    key: Option<&[u8]>,
+) -> Option<DecodedRequestKind<'a>> {
+    let request = decode_request(packet).ok()?;
+    if request.hmac_present != key.is_some() {
+        return None;
+    }
+    if let Some(key) = key {
+        verify_packet_hmac(key, packet).ok()?;
+    }
+    Some(request.kind)
+}
+
+/// Returns the requested parameters and whether this was a no-test open.
+fn open_request(packet: &[u8], key: Option<&[u8]>) -> (Params, bool) {
+    match decode_server_request(packet, key) {
+        Some(DecodedRequestKind::Open { params, no_test }) => {
+            (Params::decode(params).unwrap(), no_test)
+        }
+        other => panic!("expected an authenticated open request, got {other:?}"),
+    }
+}
+
+fn echo_request_sequence(packet: &[u8], key: Option<&[u8]>) -> u32 {
+    match decode_server_request(packet, key) {
+        Some(DecodedRequestKind::Echo { sequence, .. }) => sequence,
+        other => panic!("expected an authenticated echo request, got {other:?}"),
+    }
+}
+
+fn close_request_token(packet: &[u8], key: Option<&[u8]>) -> u64 {
+    match decode_server_request(packet, key) {
+        Some(DecodedRequestKind::Close { token }) => token,
+        other => panic!("expected an authenticated close request, got {other:?}"),
+    }
+}
+
+fn send_open_reply(
+    socket: &UdpSocket,
+    peer: SocketAddr,
+    params: Params,
+    key: Option<&[u8]>,
+    reply_flags: u8,
+    token: u64,
+) {
+    let reply = encode_open_reply(
+        &OpenReply {
+            flags: reply_flags,
+            token,
+            params,
+        },
+        key,
+    )
+    .unwrap();
+    socket.send_to(&reply, peer).unwrap();
+}
+
+fn open_session(
+    socket: &UdpSocket,
+    tx: &mpsc::Sender<Vec<u8>>,
+    key: Option<&[u8]>,
+) -> (Params, SocketAddr) {
+    let (packet, peer) = recv_packet(socket, tx);
+    let (params, _) = open_request(&packet, key);
+    send_open_reply(
+        socket,
+        peer,
+        params.clone(),
+        key,
+        flags::FLAG_OPEN | flags::FLAG_REPLY,
+        TOKEN,
+    );
+    (params, peer)
+}
+
+fn echo_reply(
+    params: &Params,
+    sequence: u32,
+    token: u64,
+    reply_flags: u8,
+    key: Option<&[u8]>,
+) -> Vec<u8> {
+    encode_echo_reply(
+        &EchoReply {
+            flags: reply_flags,
+            token,
+            sequence,
+            recv_count: None,
+            recv_window: None,
+            timestamps: TimestampFields::default(),
+            payload: Vec::new(),
+        },
+        params,
+        key,
+    )
+    .unwrap()
+}
+
+fn start_no_test_server() -> TestServer {
+    start_server(move |socket, tx| {
+        let (open_packet, peer) = recv_packet(&socket, &tx);
+        let (params, no_test) = open_request(&open_packet, None);
+        assert!(no_test);
+        send_open_reply(
+            &socket,
+            peer,
+            params,
+            None,
+            flags::FLAG_OPEN | flags::FLAG_REPLY | flags::FLAG_CLOSE,
+            0,
+        );
+    })
+}
+
+fn start_peer_close_server() -> TestServer {
+    start_server(move |socket, tx| {
+        let (params, peer) = open_session(&socket, &tx, None);
+        let (probe_packet, _) = recv_packet(&socket, &tx);
+        let sequence = echo_request_sequence(&probe_packet, None);
+        socket
+            .send_to(
+                &echo_reply(
+                    &params,
+                    sequence,
+                    TOKEN,
+                    flags::FLAG_REPLY | flags::FLAG_CLOSE,
+                    None,
+                ),
+                peer,
+            )
+            .unwrap();
+    })
+}
+
+fn poll_once<F: Future>(future: Pin<&mut F>) -> Poll<F::Output> {
+    let mut context = Context::from_waker(Waker::noop());
+    Future::poll(future, &mut context)
+}
+
+fn poll_recv_once(client: &mut AsyncClient) -> Poll<Result<Vec<ClientEvent>, ClientError>> {
+    let mut future = Box::pin(client.recv());
+    poll_once(Pin::as_mut(&mut future))
+}
+
+#[test]
+fn connect_requires_current_runtime_when_polled() {
+    let mut future = Box::pin(AsyncClient::connect(ClientConfig::default()));
+    assert!(matches!(
+        poll_once(Pin::as_mut(&mut future)),
+        Poll::Ready(Err(ClientError::NoTokioRuntime))
+    ));
+}
+
+#[test]
+fn recv_before_open_fails_on_first_poll_without_socket_readiness() {
+    runtime().block_on(async {
+        let remote = SocketAddr::from(([127, 0, 0, 1], 2112));
+        let mut client = AsyncClient::connect(config(remote, None, 0)).await.unwrap();
+
+        assert!(matches!(
+            poll_recv_once(&mut client),
+            Poll::Ready(Err(ClientError::NotOpen))
+        ));
+    });
+}
+
+#[test]
+fn ignored_open_traffic_cannot_extend_the_absolute_attempt_deadline() {
+    let server = start_server(move |socket, tx| {
+        let (first_packet, peer) = recv_packet(&socket, &tx);
+        let (params, _) = open_request(&first_packet, None);
+        socket
+            .set_read_timeout(Some(Duration::from_millis(10)))
+            .unwrap();
+        let started = Instant::now();
+        let mut next_noise = started;
+        let mut buffer = [0_u8; 512];
+
+        while started.elapsed() < Duration::from_millis(350) {
+            let now = Instant::now();
+            if now >= next_noise {
+                socket.send_to(&[0_u8], peer).unwrap();
+                next_noise = now + Duration::from_millis(25);
+            }
+            match socket.recv_from(&mut buffer) {
+                Ok((len, second_peer)) => {
+                    tx.send(buffer[..len].to_vec()).unwrap();
+                    send_open_reply(
+                        &socket,
+                        second_peer,
+                        params,
+                        None,
+                        flags::FLAG_OPEN | flags::FLAG_REPLY,
+                        TOKEN,
+                    );
+                    return;
+                }
+                Err(error)
+                    if matches!(
+                        error.kind(),
+                        io::ErrorKind::WouldBlock | io::ErrorKind::TimedOut
+                    ) => {}
+                Err(error) => panic!("{error}"),
+            }
+        }
+        panic!("second open request did not arrive after the first absolute deadline");
+    });
+    let mut client_config = config(server.addr, None, 0);
+    client_config.open_timeouts = vec![Duration::from_millis(200), Duration::from_millis(200)];
+
+    runtime().block_on(async {
+        let mut client = AsyncClient::connect(client_config).await.unwrap();
+        assert!(matches!(
+            client.open().await.unwrap(),
+            OpenOutcome::Started { .. }
+        ));
+    });
+    assert_eq!(server.finish().len(), 2);
+}
+
+#[test]
+fn authenticated_rejection_is_terminal_without_retry() {
+    let server = start_server(move |socket, tx| {
+        let (open_packet, peer) = recv_packet(&socket, &tx);
+        let (params, _) = open_request(&open_packet, None);
+        send_open_reply(
+            &socket,
+            peer,
+            params,
+            None,
+            flags::FLAG_OPEN | flags::FLAG_REPLY | flags::FLAG_CLOSE,
+            0,
+        );
+    });
+    let mut client_config = config(server.addr, None, 0);
+    client_config.open_timeouts = vec![Duration::from_millis(200), Duration::from_millis(200)];
+
+    runtime().block_on(async {
+        let mut client = AsyncClient::connect(client_config).await.unwrap();
+        assert!(matches!(
+            client.open().await,
+            Err(ClientError::ServerRejected)
+        ));
+    });
+    assert_eq!(server.finish().len(), 1);
+}
+
+#[test]
+fn recv_after_local_close_and_no_test_fails_on_first_poll() {
+    let close_server = start_server(move |socket, tx| {
+        open_session(&socket, &tx, None);
+        let (close_packet, _) = recv_packet(&socket, &tx);
+        assert_eq!(close_request_token(&close_packet, None), TOKEN);
+    });
+    runtime().block_on(async {
+        let mut client = opened_client(close_server.addr, 0).await;
+        client.close().await.unwrap();
+        assert!(matches!(
+            poll_recv_once(&mut client),
+            Poll::Ready(Err(ClientError::AlreadyClosed))
+        ));
+    });
+    assert_eq!(close_server.finish().len(), 2);
+
+    let no_test_server = start_no_test_server();
+    runtime().block_on(async {
+        let mut client_config = config(no_test_server.addr, None, 0);
+        client_config.run_mode = RunMode::NoTest;
+        let mut client = AsyncClient::connect(client_config).await.unwrap();
+        client.open().await.unwrap();
+        assert!(matches!(
+            poll_recv_once(&mut client),
+            Poll::Ready(Err(ClientError::AlreadyCompleted))
+        ));
+    });
+    assert_eq!(no_test_server.finish().len(), 1);
+}
+
+#[test]
+fn authenticated_async_lifecycle_negotiates_dscp() {
+    let key = b"async-lifecycle-key".to_vec();
+    let server = InTreeServer::start(ServerConfig::default().with_hmac_key(key.clone()));
+    runtime().block_on(async {
+        let mut client = AsyncClient::connect(config(server.addr, Some(key), 46))
+            .await
+            .unwrap();
+        let opened = client.open().await.unwrap();
+        assert_eq!(open_negotiated(&opened).params.dscp, 184);
+        client.send_probe().await.unwrap();
+        assert!(matches!(client.recv().await.unwrap().as_slice(), [ClientEvent::EchoReply { seq: 0, .. }]));
+        assert!(matches!(client.close().await.unwrap().as_slice(), [ClientEvent::SessionClosed { token, .. }] if *token == open_token(&opened)));
+    });
+}
+
+#[test]
+fn blocking_and_async_peer_close_are_semantically_equivalent() {
+    let blocking_peer_close_server = start_peer_close_server();
+    let mut blocking_peer_close =
+        Client::connect(config(blocking_peer_close_server.addr, None, 0)).unwrap();
+    blocking_peer_close.open().unwrap();
+    blocking_peer_close.send_probe().unwrap();
+    let blocking_peer_close_events = blocking_peer_close.recv_once().unwrap();
+    assert!(blocking_peer_close.is_peer_closed());
+    assert_eq!(blocking_peer_close_server.finish().len(), 2);
+
+    let async_peer_close_server = start_peer_close_server();
+    let async_peer_close_events = runtime().block_on(async {
+        let mut client = AsyncClient::connect(config(async_peer_close_server.addr, None, 0))
+            .await
+            .unwrap();
+        client.open().await.unwrap();
+        client.send_probe().await.unwrap();
+        let events = client.recv().await.unwrap();
+        assert!(client.is_peer_closed());
+        events
+    });
+    assert_eq!(async_peer_close_server.finish().len(), 2);
+    assert_eq!(
+        blocking_peer_close_events.len(),
+        async_peer_close_events.len()
+    );
+    for (blocking, asynchronous) in blocking_peer_close_events
+        .iter()
+        .zip(&async_peer_close_events)
+    {
+        assert_matching_event_shape(blocking, asynchronous);
+    }
+}
+
+fn open_negotiated(outcome: &OpenOutcome) -> &irtt_client::NegotiatedParams {
+    match outcome {
+        OpenOutcome::Started { negotiated, .. }
+        | OpenOutcome::NoTestCompleted { negotiated, .. } => negotiated,
+    }
+}
+
+fn open_token(outcome: &OpenOutcome) -> u64 {
+    match outcome {
+        OpenOutcome::Started { token, .. } => *token,
+        OpenOutcome::NoTestCompleted { .. } => panic!("no-test open has no session token"),
+    }
+}
+
+fn assert_matching_event_shape(blocking: &ClientEvent, asynchronous: &ClientEvent) {
+    assert_eq!(event_shape(blocking), event_shape(asynchronous));
+}
+
+fn event_shape(event: &ClientEvent) -> (&'static str, u64, usize) {
+    match event {
+        ClientEvent::EchoSent { seq, bytes, .. } => ("sent", u64::from(*seq), *bytes),
+        ClientEvent::EchoReply { seq, bytes, .. } => ("reply", u64::from(*seq), *bytes),
+        ClientEvent::SessionClosed { .. } => ("closed", 0, 0),
+        other => panic!("unexpected equivalence event: {other:?}"),
+    }
+}
+
+/// A peer that ignores the first `ignored_requests` datagrams before serving a
+/// compliant open, one echo, and one close.
+///
+/// Silence is the point here, so this stays a narrow fake peer rather than a
+/// real `irtt-server`: a compliant server has no way to be deliberately mute
+/// for exactly one open attempt.
+fn start_silent_then_open_server(ignored_requests: usize) -> TestServer {
+    start_server(move |socket, tx| {
+        for _ in 0..ignored_requests {
+            let _ = recv_packet(&socket, &tx);
+        }
+        let (params, peer) = open_session(&socket, &tx, None);
+        let (probe_packet, _) = recv_packet(&socket, &tx);
+        let sequence = echo_request_sequence(&probe_packet, None);
+        socket
+            .send_to(
+                &echo_reply(&params, sequence, TOKEN, flags::FLAG_REPLY, None),
+                peer,
+            )
+            .unwrap();
+        let (close_packet, _) = recv_packet(&socket, &tx);
+        assert_eq!(close_request_token(&close_packet, None), TOKEN);
+    })
+}
+
+/// Stable name for a `ClientError` variant, for comparing what each driver
+/// promises rather than how it produced it.
+fn error_name(error: &ClientError) -> &'static str {
+    match error {
+        ClientError::OpenTimeout => "open timeout",
+        ClientError::NotOpen => "not open",
+        ClientError::AlreadyOpen => "already open",
+        ClientError::AlreadyClosed => "already closed",
+        ClientError::AlreadyCompleted => "already completed",
+        ClientError::ServerRejected => "server rejected",
+        other => panic!("unexpected conformance error: {other:?}"),
+    }
+}
+
+fn probe_sequences(events: &[ClientEvent]) -> Vec<u32> {
+    events
+        .iter()
+        .filter_map(|event| match event {
+            ClientEvent::EchoSent { seq, .. } => Some(*seq),
+            _ => None,
+        })
+        .collect()
+}
+
+fn reply_sequences(events: &[ClientEvent]) -> Vec<u32> {
+    events
+        .iter()
+        .filter_map(|event| match event {
+            ClientEvent::EchoReply { seq, .. } => Some(*seq),
+            _ => None,
+        })
+        .collect()
+}
+
+#[test]
+fn blocking_and_async_roll_back_a_failed_open_and_accept_a_retry() {
+    // One open attempt is ignored, so the first open times out and the second
+    // must be able to open the same connected client.
+    let blocking_server = start_silent_then_open_server(1);
+    let mut blocking = Client::connect(config(blocking_server.addr, None, 0)).unwrap();
+    assert!(!blocking.has_pending_probes());
+    let blocking_first = blocking.open().unwrap_err();
+    assert!(!blocking.has_pending_probes());
+    let blocking_second = blocking.open().unwrap();
+    assert!(!blocking.has_pending_probes());
+    let blocking_sent = blocking.send_probe().unwrap();
+    let blocking_reply = blocking.recv_once().unwrap();
+    let blocking_close = blocking.close().unwrap();
+    assert_eq!(blocking_server.finish().len(), 4);
+
+    let async_server = start_silent_then_open_server(1);
+    let (async_first, async_second, async_sent, async_reply, async_close) =
+        runtime().block_on(async {
+            let mut client = AsyncClient::connect(config(async_server.addr, None, 0))
+                .await
+                .unwrap();
+            assert!(!client.has_pending_probes());
+            let first = client.open().await.unwrap_err();
+            assert!(!client.has_pending_probes());
+            let second = client.open().await.unwrap();
+            assert!(!client.has_pending_probes());
+            let sent = client.send_probe().await.unwrap();
+            let reply = client.recv().await.unwrap();
+            let closed = client.close().await.unwrap();
+            (first, second, sent, reply, closed)
+        });
+    assert_eq!(async_server.finish().len(), 4);
+
+    // Both drivers promise the same failure, and neither leaves the client in a
+    // state that refuses the retry.
+    assert_eq!(error_name(&blocking_first), "open timeout");
+    assert_eq!(error_name(&blocking_first), error_name(&async_first));
+    assert!(matches!(blocking_second, OpenOutcome::Started { .. }));
+    assert!(matches!(async_second, OpenOutcome::Started { .. }));
+    assert_eq!(
+        open_negotiated(&blocking_second),
+        open_negotiated(&async_second)
+    );
+    assert_eq!(open_token(&blocking_second), open_token(&async_second));
+
+    // The retried session starts a fresh probe sequence in both drivers.
+    assert_eq!(probe_sequences(&blocking_sent), [0]);
+    assert_eq!(probe_sequences(&async_sent), [0]);
+    assert_eq!(reply_sequences(&blocking_reply), [0]);
+    assert_eq!(reply_sequences(&async_reply), [0]);
+    assert_eq!(blocking_sent.len(), async_sent.len());
+    assert_eq!(blocking_reply.len(), async_reply.len());
+    assert_eq!(blocking_close.len(), async_close.len());
+    assert_matching_event_shape(&blocking_close[0], &async_close[0]);
+}
+
+#[test]
+fn blocking_and_async_complete_every_caller_paced_probe() {
+    const PROBES: u32 = 3;
+    fn caller_config(addr: SocketAddr) -> ClientConfig {
+        ClientConfig {
+            duration: Some(Duration::from_millis(1)),
+            interval: Duration::from_secs(1),
+            ..config(addr, None, 0)
+        }
+    }
+
+    let blocking_server = InTreeServer::start(ServerConfig::default());
+    let mut blocking = Client::connect(caller_config(blocking_server.addr)).unwrap();
+    let outcome = blocking.open().unwrap();
+    assert_eq!(
+        blocking.negotiated_params(),
+        Some(open_negotiated(&outcome))
+    );
+    assert!(!blocking.has_pending_probes());
+    // Oversleeping cannot invalidate this: low-level sends remain caller-owned
+    // after the negotiated duration. The compliant server has no duration cap.
+    thread::sleep(Duration::from_millis(2));
+    let mut blocking_sent = Vec::new();
+    let mut blocking_replies = Vec::new();
+    for _ in 0..PROBES {
+        blocking_sent.extend(blocking.send_probe().unwrap());
+        assert!(blocking.has_pending_probes());
+        assert!(blocking.next_probe_timeout_deadline().is_some());
+        blocking_replies.extend(blocking.recv_once().unwrap());
+        assert!(!blocking.has_pending_probes());
+    }
+    blocking.close().unwrap();
+    drop(blocking_server);
+
+    let async_server = InTreeServer::start(ServerConfig::default());
+    let (async_sent, async_replies) = runtime().block_on(async {
+        let mut client = AsyncClient::connect(caller_config(async_server.addr))
+            .await
+            .unwrap();
+        let outcome = client.open().await.unwrap();
+        assert_eq!(client.negotiated_params(), Some(open_negotiated(&outcome)));
+        tokio::time::sleep(Duration::from_millis(2)).await;
+        let mut sent = Vec::new();
+        let mut replies = Vec::new();
+        for _ in 0..PROBES {
+            sent.extend(client.send_probe().await.unwrap());
+            assert!(client.has_pending_probes());
+            assert!(client.next_probe_timeout_deadline().is_some());
+            replies.extend(client.recv().await.unwrap());
+            assert!(!client.has_pending_probes());
+        }
+        client.close().await.unwrap();
+        (sent, replies)
+    });
+    drop(async_server);
+
+    let expected: Vec<u32> = (0..PROBES).collect();
+    assert_eq!(probe_sequences(&blocking_sent), expected);
+    assert_eq!(probe_sequences(&async_sent), expected);
+    assert_eq!(reply_sequences(&blocking_replies), expected);
+    assert_eq!(reply_sequences(&async_replies), expected);
+    // Compare the whole emitted streams, not just the probe and reply events
+    // the sequence helpers keep: an extra event on either side is a difference.
+    assert_eq!(blocking_sent.len(), async_sent.len());
+    assert_eq!(blocking_replies.len(), async_replies.len());
+    for event in blocking_sent.iter().chain(&async_sent) {
+        assert!(matches!(
+            event,
+            ClientEvent::EchoSent {
+                scheduled_at: None,
+                timer_error: None,
+                ..
+            }
+        ));
+    }
+    for (blocking, asynchronous) in blocking_sent.iter().zip(&async_sent) {
+        assert_matching_event_shape(blocking, asynchronous);
+    }
+    for (blocking, asynchronous) in blocking_replies.iter().zip(&async_replies) {
+        assert_matching_event_shape(blocking, asynchronous);
+    }
+}
+
+#[test]
+fn ignored_open_traffic_uses_one_request_and_deadline_per_attempt() {
+    let server = start_server(move |socket, tx| {
+        for _ in 0..2 {
+            let (_, peer) = recv_packet(&socket, &tx);
+            for _ in 0..3 {
+                socket.send_to(&[0_u8], peer).unwrap();
+            }
+        }
+    });
+    let mut client_config = config(server.addr, None, 0);
+    client_config.open_timeouts = vec![Duration::from_millis(200), Duration::from_millis(200)];
+
+    runtime().block_on(async {
+        let mut client = AsyncClient::connect(client_config).await.unwrap();
+        assert!(matches!(client.open().await, Err(ClientError::OpenTimeout)));
+    });
+    assert_eq!(server.finish().len(), 2);
+}

crates/irtt-integration-tests/tests/blocking_managed.rs

@@ -1,6 +1,6 @@
 use std::{
     net::{SocketAddr, UdpSocket},
-    sync::{mpsc::sync_channel, Arc, Condvar, Mutex},
+    sync::{Arc, Condvar, Mutex},
     thread::{self, JoinHandle},
     time::{Duration, Instant},
 };
@@ -11,13 +11,11 @@ use irtt_proto::{
 };
 use tokio::{runtime::Builder, time::timeout};
 
-use super::{
-    blocking::{join_worker, WorkerRuntime},
-    BlockingManagedClient, BlockingManagedJoinError, ManagedClientConfig, ManagedCompletionPolicy,
-    ManagedEndReason, ManagedEvent, ManagedLifecycle, ManagedPacing, ManagedTargetConfig,
-    ManagedTargetEndReason,
+use irtt_client::managed::{
+    BlockingManagedClient, ManagedClientConfig, ManagedCompletionPolicy, ManagedEndReason,
+    ManagedEvent, ManagedLifecycle, ManagedPacing, ManagedTargetConfig, ManagedTargetEndReason,
 };
-use crate::ClientConfig;
+use irtt_client::ClientConfig;
 
 const TOKEN: u64 = 0x1234_5678_90ab_cdef;
 
@@ -167,7 +165,7 @@ fn target(server: &EchoServer) -> ManagedTargetConfig {
     ManagedTargetConfig::new("target", server.addr.to_string())
 }
 
-fn assert_stopped(outcome: &super::ManagedOutcome) {
+fn assert_stopped(outcome: &irtt_client::managed::ManagedOutcome) {
     assert_eq!(outcome.end_reason, ManagedEndReason::StopRequested);
 }
 
@@ -250,15 +248,11 @@ fn dynamic_update_reaches_background_worker() {
         .unwrap();
     let handle = owner.handle();
 
-    let acknowledgement = test_runtime().block_on(async {
-        timeout(
-            Duration::from_secs(2),
-            handle.update_targets(vec![target(&server)]).unwrap(),
-        )
-        .await
+    let acknowledgement = handle
+        .update_targets(vec![target(&server)])
         .unwrap()
-        .unwrap()
-    });
+        .blocking_wait()
+        .unwrap();
     assert_eq!(acknowledgement.sequence, 1);
     server.wait_probe();
     test_runtime().block_on(async {
@@ -313,53 +307,6 @@ fn dropping_owner_stops_and_joins_worker() {
     server.finish();
 }
 
-#[test]
-fn worker_panic_is_a_join_error() {
-    let worker = thread::spawn(|| -> super::ManagedOutcome { panic!("test worker panic") });
-    assert_eq!(
-        join_worker(worker),
-        Err(BlockingManagedJoinError::WorkerPanicked)
-    );
-}
-
-#[test]
-fn dropping_worker_runtime_inside_async_context_does_not_panic() {
-    test_runtime().block_on(async {
-        let runtime = Builder::new_current_thread()
-            .enable_io()
-            .enable_time()
-            .build()
-            .unwrap();
-        drop(WorkerRuntime::new(runtime));
-    });
-}
-
-#[test]
-fn worker_runtime_shutdown_is_bounded_with_blocking_work() {
-    let runtime = Builder::new_current_thread()
-        .enable_io()
-        .enable_time()
-        .build()
-        .unwrap();
-    let (started_send, started_receive) = sync_channel(0);
-    let (release_send, release_receive) = sync_channel(0);
-
-    runtime.block_on(async move {
-        tokio::task::spawn_blocking(move || {
-            started_send.send(()).unwrap();
-            release_receive.recv().unwrap();
-        });
-    });
-    started_receive
-        .recv_timeout(Duration::from_secs(2))
-        .unwrap();
-
-    let started = Instant::now();
-    WorkerRuntime::new(runtime).shutdown();
-    assert!(started.elapsed() < Duration::from_secs(2));
-    release_send.send(()).unwrap();
-}
-
 #[test]
 fn drop_after_natural_completion_preserves_outcome() {
     let server = EchoServer::start();

crates/irtt-integration-tests/tests/managed_behavior.rs

@@ -0,0 +1,248 @@
+mod support;
+
+use std::{collections::HashMap, time::Duration};
+
+use irtt_client::{managed::*, ClientConfig, ClientEvent};
+use irtt_server::ServerConfig;
+use support::InTreeServer;
+use tokio::time::timeout;
+
+// A real service and public events protect cadence/fairness without depending
+// on a scheduler, a send cursor, or a private event-publication hook.
+#[tokio::test(flavor = "current_thread")]
+async fn both_pacing_modes_serve_every_target_on_its_negotiated_grid() {
+    timeout(Duration::from_secs(10), async {
+        let server = InTreeServer::start(ServerConfig::default());
+        for pacing in [ManagedPacing::Burst, ManagedPacing::Staggered] {
+            let mut observed_pacing = false;
+            for _ in 0..3 {
+                let config = ManagedClientConfig {
+                    client: ClientConfig {
+                        duration: Some(Duration::from_millis(600)),
+                        interval: Duration::from_millis(100),
+                        probe_timeout: Duration::from_millis(100),
+                        open_timeouts: vec![Duration::from_millis(200)],
+                        ..ClientConfig::default()
+                    },
+                    pacing,
+                    ..ManagedClientConfig::default()
+                };
+                let targets = ["first", "second"]
+                    .map(|id| ManagedTargetConfig::new(id, server.addr.to_string()));
+                let (task, handle) = ManagedClient::task(config, targets.into()).unwrap();
+                let mut events = handle.subscribe().unwrap();
+                let run = tokio::spawn(task);
+                let mut sends: HashMap<TargetInstance, Vec<_>> = HashMap::new();
+                let mut actual_sends = Vec::new();
+                while let Ok(event) = events.recv().await {
+                    if let ManagedEvent::Client {
+                        target,
+                        event:
+                            ClientEvent::EchoSent {
+                                scheduled_at,
+                                sent_at,
+                                ..
+                            },
+                    } = event
+                    {
+                        let scheduled = scheduled_at.expect("managed probes expose their cadence");
+                        assert!(sent_at.mono >= scheduled);
+                        actual_sends.push((target.clone(), sent_at.mono));
+                        let previous = sends.entry(target).or_default();
+                        if let Some(last) = previous.last() {
+                            let elapsed: Duration = scheduled.duration_since(*last);
+                            assert!(!elapsed.is_zero());
+                            assert_eq!(
+                                elapsed.as_nanos() % Duration::from_millis(100).as_nanos(),
+                                0
+                            );
+                        }
+                        previous.push(scheduled);
+                    }
+                }
+                let outcome = run.await.unwrap();
+                assert_eq!(outcome.end_reason, ManagedEndReason::TargetsComplete);
+                assert_eq!(outcome.successful_target_outcomes, 2);
+                assert_eq!(sends.len(), 2);
+                for target in outcome.recent_target_outcomes.iter() {
+                    assert!(sends[&target.target].len() >= 2);
+                    assert!(target.replies_received >= 2);
+                }
+                // Use only the initial pair: later stagger gates can legitimately
+                // compress after a delayed wake. Startup may instead serve one
+                // target twice before the other opens, so retry a fresh run then.
+                if actual_sends.len() < 2 || actual_sends[0].0 == actual_sends[1].0 {
+                    continue;
+                }
+                let gap = actual_sends[1].1.duration_since(actual_sends[0].1);
+                match pacing {
+                    ManagedPacing::Staggered => {
+                        assert!(
+                            gap >= Duration::from_millis(50),
+                            "first stagger gate was bypassed: {gap:?}"
+                        );
+                        observed_pacing = true;
+                    }
+                    ManagedPacing::Burst => {
+                        // A pause between burst sends makes this observation
+                        // inconclusive; it must not fail an otherwise valid run.
+                        observed_pacing = gap < Duration::from_millis(25);
+                    }
+                }
+                if observed_pacing {
+                    break;
+                }
+            }
+            assert!(
+                observed_pacing,
+                "could not observe {pacing:?} startup pacing in three fresh runs"
+            );
+        }
+    })
+    .await
+    .expect("managed pacing did not complete");
+}
+
+// Updates, receipts, generations and cleanup are observable through the control
+// handle and event subscription; no task internals or artificial races are needed.
+#[tokio::test(flavor = "current_thread")]
+async fn target_updates_preserve_identical_sessions_and_retire_removed_generations() {
+    timeout(Duration::from_secs(5), async {
+        let server = InTreeServer::start(ServerConfig::default());
+        let config = ManagedClientConfig {
+            client: ClientConfig {
+                duration: None,
+                interval: Duration::from_millis(20),
+                probe_timeout: Duration::from_millis(100),
+                open_timeouts: vec![Duration::from_millis(200)],
+                ..ClientConfig::default()
+            },
+            completion: ManagedCompletionPolicy::ExplicitStop,
+            outcome_history_limit: 1,
+            ..ManagedClientConfig::default()
+        };
+        let configured = ManagedTargetConfig::new("one", server.addr.to_string());
+        let (task, handle) = ManagedClient::task(config, vec![]).unwrap();
+        let mut events = handle.subscribe().unwrap();
+        let run = tokio::spawn(task);
+        let added = handle
+            .update_targets(vec![configured.clone()])
+            .unwrap()
+            .await
+            .unwrap();
+        let first = added.status.targets[0].target.clone();
+        loop {
+            if matches!(events.recv().await.unwrap(), ManagedEvent::Client {
+                target, event: ClientEvent::EchoReply { .. }
+            } if target == first)
+            {
+                break;
+            }
+        }
+        let identical = handle
+            .update_targets(vec![configured.clone()])
+            .unwrap()
+            .await
+            .unwrap();
+        assert_eq!(identical.status.targets.len(), 1);
+        assert_eq!(identical.status.targets[0].target, first);
+        loop {
+            match events.recv().await.unwrap() {
+                ManagedEvent::Client {
+                    target,
+                    event: ClientEvent::SessionStarted { .. },
+                } if target == first => panic!("identical update reopened the session"),
+                ManagedEvent::Client {
+                    target,
+                    event: ClientEvent::EchoReply { .. },
+                } if target == first => break,
+                _ => {}
+            }
+        }
+        handle.update_targets(vec![]).unwrap().await.unwrap();
+        loop {
+            if let ManagedEvent::TargetFinished { outcome } = events.recv().await.unwrap() {
+                let status = handle.status();
+                assert_eq!(outcome.target, first);
+                assert_eq!(outcome.end_reason, ManagedTargetEndReason::Removed);
+                assert_eq!(outcome.cleanup_failure, None);
+                assert_eq!(status.total_target_outcomes, 1);
+                assert_eq!(status.successful_target_outcomes, 1);
+                assert_eq!(
+                    status.recent_target_outcomes.as_ref(),
+                    &[(*outcome).clone()]
+                );
+                assert!(status.targets.iter().all(|target| target.target != first
+                    || target.lifecycle == ManagedTargetLifecycle::Terminal));
+                break;
+            }
+        }
+        let readded = handle
+            .update_targets(vec![configured])
+            .unwrap()
+            .await
+            .unwrap();
+        let second = readded
+            .status
+            .targets
+            .iter()
+            .find(|target| target.desired)
+            .unwrap()
+            .target
+            .clone();
+        assert!(second.generation > first.generation);
+        loop {
+            if matches!(events.recv().await.unwrap(), ManagedEvent::Client {
+                target, event: ClientEvent::EchoReply { .. }
+            } if target == second)
+            {
+                break;
+            }
+        }
+        let stop = handle.stop();
+        loop {
+            match events.recv().await.unwrap() {
+                ManagedEvent::TargetFinished { outcome } => {
+                    let status = handle.status();
+                    assert_eq!(outcome.target, second);
+                    assert_eq!(status.total_target_outcomes, 2);
+                    assert_eq!(
+                        status.recent_target_outcomes.as_ref(),
+                        &[(*outcome).clone()]
+                    );
+                    assert!(status.targets.iter().all(|target| target.target != second
+                        || target.lifecycle == ManagedTargetLifecycle::Terminal));
+                }
+                ManagedEvent::Completed { outcome } => {
+                    let status = handle.status();
+                    assert_eq!(status.lifecycle, ManagedLifecycle::Completed);
+                    assert_eq!(status.final_outcome.as_ref(), Some(&outcome));
+                    break;
+                }
+                _ => {}
+            }
+        }
+        let outcome = run.await.unwrap();
+        stop.await;
+        assert_eq!(outcome.end_reason, ManagedEndReason::StopRequested);
+        assert_eq!(outcome.total_target_outcomes, 2);
+        assert_eq!(outcome.successful_target_outcomes, 2);
+        assert_eq!(outcome.failed_target_outcomes, 0);
+        assert_eq!(outcome.discarded_target_outcomes, 1);
+        assert_eq!(outcome.recent_target_outcomes.len(), 1);
+        let status = handle.status();
+        assert_eq!(status.total_target_outcomes, 2);
+        assert_eq!(status.successful_target_outcomes, 2);
+        assert_eq!(status.failed_target_outcomes, 0);
+        assert_eq!(status.discarded_target_outcomes, 1);
+        assert_eq!(status.recent_target_outcomes.len(), 1);
+        assert_eq!(status.recent_target_outcomes[0].target, second);
+        assert!(outcome.recent_target_outcomes.iter().any(|target| {
+            target.target == second
+                && target.end_reason == ManagedTargetEndReason::Stopped
+                && target.cleanup_failure.is_none()
+        }));
+    })
+    .await
+    .expect("managed target updates did not complete");
+}

crates/irtt-integration-tests/tests/managed_lifecycle.rs

@@ -0,0 +1,506 @@
+use std::{
+    future::Future,
+    net::{SocketAddr, UdpSocket},
+    pin::Pin,
+    sync::{Arc, Mutex},
+    task::{Context, Poll, Waker},
+    thread::{self, JoinHandle},
+    time::{Duration, Instant},
+};
+
+use irtt_proto::{
+    decode_request, encode_echo_reply, encode_open_reply, flags, verify_packet_hmac,
+    DecodedRequestKind, EchoReply, OpenReply, Params, ReceivedStats, StampAt, TimestampFields,
+};
+use tokio::runtime::{Builder, Runtime};
+
+use irtt_client::{managed::*, ClientConfig};
+use irtt_client::{ClientAuthConfig, RunMode};
+use tokio::sync::broadcast;
+
+const TOKEN: u64 = 0x1234_5678_90ab_cdef;
+
+#[derive(Clone, Copy)]
+enum ServerBehavior {
+    Echo,
+    NoTest,
+    PeerClose,
+    DelayedEcho(Duration),
+}
+
+#[derive(Clone, Debug)]
+enum PacketKind {
+    Open,
+    Probe,
+    Close,
+}
+
+#[derive(Clone, Debug)]
+struct PacketRecord {
+    kind: PacketKind,
+    at: Instant,
+}
+
+struct TestServer {
+    addr: SocketAddr,
+    records: Arc<Mutex<Vec<PacketRecord>>>,
+    thread: JoinHandle<()>,
+}
+
+impl TestServer {
+    fn finish(self) -> Vec<PacketRecord> {
+        self.thread.join().unwrap();
+        self.records.lock().unwrap().clone()
+    }
+}
+
+/// Admits a request the way a compliant server does: structural decode first,
+/// then HMAC presence policy, then authentication. Returns `None` for anything
+/// a server would silently discard.
+fn decode_server_request<'a>(
+    packet: &'a [u8],
+    key: Option<&[u8]>,
+) -> Option<DecodedRequestKind<'a>> {
+    let request = decode_request(packet).ok()?;
+    if request.hmac_present != key.is_some() {
+        return None;
+    }
+    if let Some(key) = key {
+        verify_packet_hmac(key, packet).ok()?;
+    }
+    Some(request.kind)
+}
+
+fn decode_open_params(packet: &[u8], key: Option<&[u8]>) -> Params {
+    match decode_server_request(packet, key) {
+        Some(DecodedRequestKind::Open { params, .. }) => Params::decode(params).unwrap(),
+        other => panic!("expected an authenticated open request, got {other:?}"),
+    }
+}
+
+fn start_server(behavior: ServerBehavior, key: Option<Vec<u8>>) -> TestServer {
+    let socket = UdpSocket::bind("127.0.0.1:0").unwrap();
+    socket
+        .set_read_timeout(Some(Duration::from_secs(3)))
+        .unwrap();
+    let addr = socket.local_addr().unwrap();
+    let records = Arc::new(Mutex::new(Vec::new()));
+    let thread_records = Arc::clone(&records);
+    let thread = thread::spawn(move || {
+        let mut buffer = [0_u8; 8192];
+        let (open_len, peer) = socket.recv_from(&mut buffer).unwrap();
+        thread_records.lock().unwrap().push(PacketRecord {
+            kind: PacketKind::Open,
+            at: Instant::now(),
+        });
+        let negotiated = decode_open_params(&buffer[..open_len], key.as_deref());
+        let no_test = matches!(behavior, ServerBehavior::NoTest);
+        let open_reply = encode_open_reply(
+            &OpenReply {
+                flags: flags::FLAG_OPEN
+                    | flags::FLAG_REPLY
+                    | if no_test { flags::FLAG_CLOSE } else { 0 },
+                token: if no_test { 0 } else { TOKEN },
+                params: negotiated.clone(),
+            },
+            key.as_deref(),
+        )
+        .unwrap();
+        socket.send_to(&open_reply, peer).unwrap();
+        if no_test {
+            return;
+        }
+
+        loop {
+            let Ok((len, packet_peer)) = socket.recv_from(&mut buffer) else {
+                return;
+            };
+            let packet = &buffer[..len];
+            match decode_server_request(packet, key.as_deref()) {
+                Some(DecodedRequestKind::Echo { sequence, .. }) => {
+                    thread_records.lock().unwrap().push(PacketRecord {
+                        kind: PacketKind::Probe,
+                        at: Instant::now(),
+                    });
+                    if let ServerBehavior::DelayedEcho(delay) = behavior {
+                        thread::sleep(delay);
+                    }
+                    let peer_close = matches!(behavior, ServerBehavior::PeerClose);
+                    let reply = encode_echo_reply(
+                        &EchoReply {
+                            flags: flags::FLAG_REPLY
+                                | if peer_close { flags::FLAG_CLOSE } else { 0 },
+                            token: TOKEN,
+                            sequence,
+                            recv_count: None,
+                            recv_window: None,
+                            timestamps: TimestampFields::default(),
+                            payload: Vec::new(),
+                        },
+                        &negotiated,
+                        key.as_deref(),
+                    )
+                    .unwrap();
+                    socket.send_to(&reply, packet_peer).unwrap();
+                    if peer_close {
+                        return;
+                    }
+                }
+                Some(DecodedRequestKind::Close { .. }) => {
+                    thread_records.lock().unwrap().push(PacketRecord {
+                        kind: PacketKind::Close,
+                        at: Instant::now(),
+                    });
+                    return;
+                }
+                Some(DecodedRequestKind::Open { .. }) | None => {}
+            }
+        }
+    });
+    TestServer {
+        addr,
+        records,
+        thread,
+    }
+}
+
+fn runtime() -> Runtime {
+    Builder::new_current_thread()
+        .enable_io()
+        .enable_time()
+        .build()
+        .unwrap()
+}
+
+fn config(pacing: ManagedPacing) -> ManagedClientConfig {
+    ManagedClientConfig {
+        client: ClientConfig {
+            duration: Some(Duration::from_millis(130)),
+            interval: Duration::from_millis(60),
+            probe_timeout: Duration::from_millis(35),
+            open_timeouts: vec![Duration::from_millis(200)],
+            received_stats: ReceivedStats::None,
+            stamp_at: StampAt::None,
+            ..ClientConfig::default()
+        },
+        pacing,
+        final_drain: Duration::from_millis(5),
+        ..ManagedClientConfig::default()
+    }
+}
+
+fn target(id: &str, addr: SocketAddr) -> ManagedTargetConfig {
+    ManagedTargetConfig::new(id, addr.to_string())
+}
+
+fn poll_once<F: Future>(future: Pin<&mut F>) -> Poll<F::Output> {
+    Future::poll(future, &mut Context::from_waker(Waker::noop()))
+}
+
+fn probes(records: &[PacketRecord]) -> Vec<Instant> {
+    records
+        .iter()
+        .filter_map(|record| matches!(record.kind, PacketKind::Probe).then_some(record.at))
+        .collect()
+}
+
+fn has_close(records: &[PacketRecord]) -> bool {
+    records
+        .iter()
+        .any(|record| matches!(record.kind, PacketKind::Close))
+}
+
+#[test]
+fn construction_is_runtime_and_io_free() {
+    let (task, handle) = ManagedClient::task(
+        config(ManagedPacing::Staggered),
+        vec![ManagedTargetConfig::new("dns", "no-such-host.invalid")],
+    )
+    .unwrap();
+    assert_eq!(handle.status().lifecycle, ManagedLifecycle::NotStarted);
+    drop(task);
+}
+
+#[test]
+fn quiescent_rejects_empty_initial_targets() {
+    assert!(matches!(
+        ManagedClient::task(config(ManagedPacing::Staggered), vec![]),
+        Err(ManagedConfigError::EmptyInitialTargets)
+    ));
+}
+
+#[test]
+fn explicit_empty_waits_for_stop() {
+    let mut config = config(ManagedPacing::Staggered);
+    config.completion = ManagedCompletionPolicy::ExplicitStop;
+    let (task, handle) = ManagedClient::task(config, vec![]).unwrap();
+    let outcome = runtime().block_on(async move {
+        let mut task = Box::pin(task);
+        assert!(
+            tokio::time::timeout(Duration::from_millis(20), task.as_mut())
+                .await
+                .is_err()
+        );
+        assert_eq!(handle.status().lifecycle, ManagedLifecycle::Running);
+        let receipt = handle.stop();
+        let outcome = task.await;
+        receipt.await;
+        outcome
+    });
+    assert_eq!(outcome.end_reason, ManagedEndReason::StopRequested);
+}
+
+#[test]
+fn extreme_event_capacity_is_rejected_without_panic() {
+    let mut managed = config(ManagedPacing::Staggered);
+    managed.completion = ManagedCompletionPolicy::ExplicitStop;
+    managed.event_capacity = usize::MAX;
+    assert!(matches!(
+        ManagedClient::task(managed, vec![]),
+        Err(ManagedConfigError::EventCapacityTooLarge {
+            configured: usize::MAX,
+            ..
+        })
+    ));
+}
+
+#[test]
+fn extreme_command_capacity_is_rejected_without_panic() {
+    let mut managed = config(ManagedPacing::Staggered);
+    managed.completion = ManagedCompletionPolicy::ExplicitStop;
+    managed.command_capacity = usize::MAX;
+    assert!(matches!(
+        ManagedClient::task(managed, vec![]),
+        Err(ManagedConfigError::CommandCapacityTooLarge {
+            configured: usize::MAX,
+            ..
+        })
+    ));
+}
+
+#[test]
+fn first_poll_without_runtime_fails_durably() {
+    let (task, handle) = ManagedClient::task(
+        config(ManagedPacing::Staggered),
+        vec![target("one", "127.0.0.1:9".parse().unwrap())],
+    )
+    .unwrap();
+    let mut task = Box::pin(task);
+    let Poll::Ready(outcome) = poll_once(task.as_mut()) else {
+        panic!("task did not fail on its first poll")
+    };
+    assert_eq!(
+        outcome.end_reason,
+        ManagedEndReason::DriverFailed(ManagedDriverFailure::NoTokioRuntime)
+    );
+    assert_eq!(handle.status().lifecycle, ManagedLifecycle::Failed);
+}
+
+#[test]
+fn pre_poll_stop() {
+    let (task, handle) = ManagedClient::task(
+        config(ManagedPacing::Staggered),
+        vec![ManagedTargetConfig::new("one", "no-such-host.invalid")],
+    )
+    .unwrap();
+    let mut receipt = Box::pin(handle.stop());
+    let mut task = Box::pin(task);
+    let Poll::Ready(outcome) = poll_once(task.as_mut()) else {
+        panic!("pre-stopped task did not complete")
+    };
+    assert!(poll_once(receipt.as_mut()).is_ready());
+    assert_eq!(outcome.end_reason, ManagedEndReason::StopRequested);
+}
+
+#[test]
+fn finite_immediate_replies_use_retained_drain_deadline() {
+    let server = start_server(ServerBehavior::Echo, None);
+    let mut managed = config(ManagedPacing::Staggered);
+    managed.client.probe_timeout = Duration::from_secs(3);
+    managed.final_drain = Duration::from_millis(30);
+    let (task, _) = ManagedClient::task(managed, vec![target("one", server.addr)]).unwrap();
+    let started_at = Instant::now();
+    let outcome = runtime().block_on(async {
+        tokio::time::timeout(Duration::from_secs(1), task)
+            .await
+            .expect("replied probes must not hold the drain until their obsolete timeout")
+    });
+    assert!(started_at.elapsed() < Duration::from_secs(1));
+    let records = server.finish();
+    assert_eq!(outcome.end_reason, ManagedEndReason::TargetsComplete);
+    assert!(matches!(
+        outcome.recent_target_outcomes[0].end_reason,
+        ManagedTargetEndReason::TestComplete
+    ));
+    assert!(!probes(&records).is_empty() && has_close(&records));
+}
+
+#[test]
+fn no_test_target_completion() {
+    let server = start_server(ServerBehavior::NoTest, None);
+    let mut config = config(ManagedPacing::Staggered);
+    config.client.run_mode = RunMode::NoTest;
+    let (task, _) = ManagedClient::task(config, vec![target("no-test", server.addr)]).unwrap();
+    let outcome = runtime().block_on(task);
+    let records = server.finish();
+    assert!(matches!(
+        outcome.recent_target_outcomes[0].end_reason,
+        ManagedTargetEndReason::NoTestComplete
+    ));
+    assert!(probes(&records).is_empty() && !has_close(&records));
+}
+
+#[test]
+fn authenticated_peer_close_outcome() {
+    let key = b"managed-peer-close".to_vec();
+    let server = start_server(ServerBehavior::PeerClose, Some(key.clone()));
+    let mut configured = target("peer", server.addr);
+    configured.auth = Some(ClientAuthConfig {
+        hmac_key: Some(key),
+    });
+    let (task, _) =
+        ManagedClient::task(config(ManagedPacing::Staggered), vec![configured]).unwrap();
+    let outcome = runtime().block_on(task);
+    let records = server.finish();
+    assert_eq!(outcome.peer_closed_target_outcomes, 1);
+    assert!(matches!(
+        outcome.recent_target_outcomes[0].end_reason,
+        ManagedTargetEndReason::PeerClosed
+    ));
+    assert!(!has_close(&records));
+}
+
+#[test]
+fn static_multi_target_completion() {
+    let first = start_server(ServerBehavior::Echo, None);
+    let second = start_server(ServerBehavior::Echo, None);
+    let (task, _) = ManagedClient::task(
+        config(ManagedPacing::Burst),
+        vec![target("first", first.addr), target("second", second.addr)],
+    )
+    .unwrap();
+    let outcome = runtime().block_on(task);
+    assert_eq!(outcome.total_target_outcomes, 2);
+    assert_eq!(outcome.successful_target_outcomes, 2);
+    assert!(!probes(&first.finish()).is_empty());
+    assert!(!probes(&second.finish()).is_empty());
+}
+
+#[test]
+fn sibling_failure_isolation() {
+    let good = start_server(ServerBehavior::Echo, None);
+    let unused = UdpSocket::bind("127.0.0.1:0").unwrap();
+    let bad_addr = unused.local_addr().unwrap();
+    drop(unused);
+    let (task, _) = ManagedClient::task(
+        config(ManagedPacing::Staggered),
+        vec![target("good", good.addr), target("bad", bad_addr)],
+    )
+    .unwrap();
+    let outcome = runtime().block_on(task);
+    assert_eq!(outcome.total_target_outcomes, 2);
+    assert_eq!(outcome.successful_target_outcomes, 1);
+    assert_eq!(outcome.failed_target_outcomes, 1);
+    assert!(!probes(&good.finish()).is_empty());
+}
+
+#[test]
+fn pending_limit_failure_drains_reply_and_closes_session() {
+    let key = b"managed-send-failure-cleanup".to_vec();
+    let server = start_server(
+        ServerBehavior::DelayedEcho(Duration::from_millis(80)),
+        Some(key.clone()),
+    );
+    let mut managed = config(ManagedPacing::Staggered);
+    managed.client.duration = Some(Duration::from_millis(250));
+    managed.client.interval = Duration::from_millis(20);
+    managed.client.probe_timeout = Duration::from_secs(2);
+    managed.client.max_pending_probes = 1;
+    managed.final_drain = Duration::from_millis(50);
+    let mut configured = target("one", server.addr);
+    configured.auth = Some(ClientAuthConfig {
+        hmac_key: Some(key),
+    });
+    let (task, _) = ManagedClient::task(managed, vec![configured]).unwrap();
+    let outcome = runtime().block_on(async {
+        tokio::time::timeout(Duration::from_secs(1), task)
+            .await
+            .expect("send failure cleanup must shorten after draining the committed reply")
+    });
+    let records = server.finish();
+    let target = &outcome.recent_target_outcomes[0];
+    assert_eq!(outcome.failed_target_outcomes, 1);
+    assert!(matches!(
+        target.end_reason,
+        ManagedTargetEndReason::Failed(ManagedTargetFailure {
+            phase: ManagedTargetFailurePhase::Sending,
+            kind: ManagedTargetFailureKind::ResourceExhausted,
+            ..
+        })
+    ));
+    assert_eq!(target.cleanup_failure, None);
+    assert_eq!(target.packets_sent, 1);
+    assert_eq!(target.replies_received, 1);
+    assert_eq!(probes(&records).len(), 1);
+    assert!(has_close(&records));
+}
+
+#[test]
+fn event_loss_independence() {
+    let server = start_server(ServerBehavior::Echo, None);
+    let mut config = config(ManagedPacing::Staggered);
+    config.event_capacity = 1;
+    let (task, handle) = ManagedClient::task(config, vec![target("one", server.addr)]).unwrap();
+    let mut events = handle.subscribe().unwrap();
+    let outcome = runtime().block_on(task);
+    assert!(matches!(
+        events.try_recv(),
+        Err(broadcast::error::TryRecvError::Lagged(_))
+    ));
+    assert_eq!(outcome.successful_target_outcomes, 1);
+    assert_eq!(handle.status().lifecycle, ManagedLifecycle::Completed);
+    server.finish();
+}
+
+#[test]
+fn dropping_all_handles_does_not_stop() {
+    let server = start_server(ServerBehavior::Echo, None);
+    let (task, handle) = ManagedClient::task(
+        config(ManagedPacing::Staggered),
+        vec![target("one", server.addr)],
+    )
+    .unwrap();
+    drop(handle);
+    let outcome = runtime().block_on(task);
+    assert_eq!(outcome.end_reason, ManagedEndReason::TargetsComplete);
+    server.finish();
+}
+
+#[test]
+fn task_drop_abandonment() {
+    let (task, handle) = ManagedClient::task(
+        config(ManagedPacing::Staggered),
+        vec![target("one", "127.0.0.1:9".parse().unwrap())],
+    )
+    .unwrap();
+    let mut events = handle.subscribe().unwrap();
+    drop(task);
+    assert_eq!(handle.status().lifecycle, ManagedLifecycle::Abandoned);
+    assert_eq!(handle.status().total_target_outcomes, 0);
+    assert!(matches!(events.try_recv(), Ok(ManagedEvent::Abandoned)));
+}
+
+#[test]
+fn terminal_subscription_is_closed() {
+    let (task, handle) = ManagedClient::task(
+        config(ManagedPacing::Staggered),
+        vec![target("one", "127.0.0.1:9".parse().unwrap())],
+    )
+    .unwrap();
+    let mut task = Box::pin(task);
+    assert!(poll_once(task.as_mut()).is_ready());
+    assert!(matches!(
+        handle.subscribe(),
+        Err(ManagedSubscribeError::Closed)
+    ));
+}

crates/irtt-proto/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "irtt-proto"
-version = "0.5.0"
+version = "0.5.1"
 description = "IRTT protocol encoding and decoding primitives"
 edition.workspace = true
 license.workspace = true
@@ -15,7 +15,7 @@ categories = ["network-programming"]
 hmac = "0.13"
 md-5 = "0.11"
 subtle = "2.6.1"
-thiserror = "2.0.20"
+thiserror = "2.0.21"
 
 [dev-dependencies]
 proptest = "1.11.0"

crates/irtt-proto/src/echo.rs

@@ -60,6 +60,50 @@ pub struct TimestampFields {
     pub send_mono: Option<i64>,
 }
 
+/// Encodes an ECHO reply.
+///
+/// `params` supplies the negotiated layout and length, exactly as on the
+/// request side, and every optional field the layout requires must be present
+/// in `reply`: a `Some` where the layout has no field, or a `None` where it has
+/// one, is an error. `hmac_key` is authoritative: `Some(key)` sets `FLAG_HMAC`
+/// and signs the finished datagram.
+///
+/// # Errors
+///
+/// Returns [`ProtoError::MissingFlag`] or [`ProtoError::UnexpectedFlag`] when
+/// the reply does not carry exactly the packet-type flags this encoder
+/// requires, [`ProtoError::MissingField`] or [`ProtoError::UnexpectedField`]
+/// when `reply`'s optional fields do not match the negotiated layout, and
+/// [`ProtoError::PayloadTooLarge`] when the payload does not fit the negotiated
+/// length.
+///
+/// # Example
+///
+/// ```
+/// use irtt_proto::{
+///     decode_echo_reply, encode_echo_reply, EchoReply, Params, ReceivedStats,
+///     TimestampFields, FLAG_REPLY,
+/// };
+///
+/// // `received_stats` negotiates a receive counter; four payload bytes.
+/// let params = Params {
+///     length: 24,
+///     received_stats: ReceivedStats::Count,
+///     ..Params::default()
+/// };
+/// let reply = EchoReply {
+///     flags: FLAG_REPLY,
+///     token: 0x1234_5678_9abc_def0,
+///     sequence: 7,
+///     recv_count: Some(3),
+///     recv_window: None,
+///     timestamps: TimestampFields::default(),
+///     payload: vec![1, 2, 3, 4],
+/// };
+///
+/// let packet = encode_echo_reply(&reply, &params, None).unwrap();
+/// assert_eq!(decode_echo_reply(&packet, &params, None).unwrap(), reply);
+/// ```
 pub fn encode_echo_reply(
     reply: &EchoReply,
     params: &Params,

crates/irtt-proto/src/hmac.rs

@@ -68,6 +68,23 @@ pub fn verify_hmac(key: &[u8], packet: &[u8], hmac_offset: usize) -> Result<()>
 /// [`ProtoError::InvalidHmacOffset`] when the field is truncated, and
 /// [`ProtoError::BadHmac`] when the MAC does not match. The packet is never
 /// modified.
+///
+/// # Example
+///
+/// ```
+/// use irtt_proto::{encode_request, verify_packet_hmac, Params, RequestToEncode};
+///
+/// // Synthetic example key — use a real shared secret in production.
+/// let key = b"example key";
+/// let params = Params::with_protocol_defaults();
+/// let packet = encode_request(
+///     RequestToEncode::Open { params: &params, no_test: false },
+///     Some(key),
+/// ).unwrap();
+///
+/// verify_packet_hmac(key, &packet).unwrap();
+/// assert!(verify_packet_hmac(b"wrong key", &packet).is_err());
+/// ```
 pub fn verify_packet_hmac(key: &[u8], packet: &[u8]) -> Result<()> {
     let envelope = envelope::decode_structural(packet)?;
     if !envelope.hmac_present {

crates/irtt-proto/src/layout.rs

@@ -135,6 +135,20 @@ pub fn echo_header_len(hmac: bool, params: &Params) -> usize {
 /// A ceiling on what a negotiated length may legitimately *be* — an MTU, a
 /// resource bound, a maximum packet size — is deliberately not here. That is
 /// server and runtime policy, and it belongs where the negotiation happens.
+///
+/// # Example
+///
+/// ```
+/// use irtt_proto::{echo_packet_len, Params};
+///
+/// // The default layout's mandatory field block is 16 bytes (header, token,
+/// // sequence), so a smaller requested length is floored up to it.
+/// assert_eq!(echo_packet_len(false, &Params::default()).unwrap(), 16);
+/// assert_eq!(
+///     echo_packet_len(false, &Params { length: 40, ..Params::default() }).unwrap(),
+///     40,
+/// );
+/// ```
 pub fn echo_packet_len(hmac: bool, params: &Params) -> Result<usize> {
     let header_len = echo_header_len(hmac, params);
     let requested = if params.length <= 0 {