chore(deps): update github actions

Allow targets to automatically restart after completing or failing, and ensure distinct state and statistics across successive target generations.

.gitea/workflows/ci.yml

@@ -7,7 +7,6 @@ on:
   pull_request:
     branches:
       - main
-  merge_group:
   workflow_dispatch:
 
 permissions:
@@ -24,15 +23,15 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
         with:
           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
@@ -44,15 +43,15 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
         with:
           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: |
@@ -72,58 +71,65 @@ jobs:
             --locked \
             -- -D warnings
 
-  check:
-    name: cargo check
-    runs-on: ubuntu-latest
-    timeout-minutes: 20
+  verify:
+    name: cargo ${{ matrix.task }} (${{ matrix.target }})
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - task: check
+            target: x86_64-unknown-linux-gnu
+            musl: false
 
-    steps:
-      - name: Checkout
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
-        with:
-          persist-credentials: false
+          - task: test
+            target: x86_64-unknown-linux-gnu
+            musl: false
 
-      - name: Install Rust toolchain
-        uses: actions-rust-lang/setup-rust-toolchain@166cdcfd11aee3cb47222f9ddb555ce30ddb9659 # v1
-        with:
-          cache-key: check
+          - task: check
+            target: x86_64-unknown-linux-musl
+            musl: true
 
-      - name: Run check without default features
-        run: |
-          cargo check \
-            --workspace \
-            --no-default-features \
-            --locked
+          - task: test
+            target: x86_64-unknown-linux-musl
+            musl: true
 
-  test:
-    name: cargo test
     runs-on: ubuntu-latest
     timeout-minutes: 25
 
     steps:
       - name: Checkout
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
         with:
           persist-credentials: false
 
-      - name: Install Rust toolchain
-        uses: actions-rust-lang/setup-rust-toolchain@166cdcfd11aee3cb47222f9ddb555ce30ddb9659 # v1
-        with:
-          cache-key: test
-
-      - name: Run tests
+      - name: Install musl toolchain
+        if: matrix.musl
         run: |
-          cargo test \
+          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: false
+
+      - name: Run ${{ matrix.task }} with all features
+        run: |
+          cargo ${{ matrix.task }} \
             --workspace \
             --all-targets \
             --all-features \
+            --target ${{ matrix.target }} \
             --locked
 
-      - name: Run tests without default features
+      - name: Run ${{ matrix.task }} without default features
         run: |
-          cargo test \
+          cargo ${{ matrix.task }} \
             --workspace \
+            --all-targets \
             --no-default-features \
+            --target ${{ matrix.target }} \
             --locked
 
   docs:
@@ -136,14 +142,14 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
         with:
           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: |
@@ -152,3 +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

@@ -0,0 +1,81 @@
+name: Fuzz Smoke
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+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:
+    name: cargo fuzz smoke
+    runs-on: ubuntu-latest
+    timeout-minutes: 20
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
+        with:
+          persist-credentials: false
+
+      - name: Install stable Rust toolchain
+        uses: actions-rust-lang/setup-rust-toolchain@ecabd13d1c56bd1345c230e542e9144811ad706f # v2
+        with:
+          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
+        # 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 "${FUZZ_TOOLCHAIN}" --profile minimal --no-self-update
+
+      - name: Install cargo-fuzz
+        run: |
+          set -euo pipefail
+          archive="cargo-fuzz-${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" >> "$GITHUB_PATH"
+
+      - name: Build all fuzz targets
+        # libFuzzer sanitizers require dynamically linked GNU binaries; the
+        # runner's default Rust host can be static musl.
+        run: RUSTUP_TOOLCHAIN="${FUZZ_TOOLCHAIN}" cargo fuzz build --target "${FUZZ_TARGET}"
+        working-directory: fuzz
+
+      - name: Run bounded fuzz smoke for every target
+        # A single job building once and running each target sequentially
+        # avoids recompiling the fuzz workspace per target. Ten seconds per
+        # target is enough to catch a broken harness or an obvious
+        # 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 server_core_datagrams; do
+            echo "::group::fuzz smoke: ${target}"
+            RUSTUP_TOOLCHAIN="${FUZZ_TOOLCHAIN}" cargo fuzz run --target "${FUZZ_TARGET}" "${target}" -- \
+              -max_total_time=10 \
+              -timeout=5
+            echo "::endgroup::"
+          done
+        working-directory: fuzz

.gitea/workflows/interop-netem.yml

@@ -25,20 +25,21 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
         with:
           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: |
@@ -46,8 +47,8 @@ jobs:
           go install "github.com/heistp/irtt/cmd/irtt@${IRTT_UPSTREAM_VERSION}"
           "$GOBIN/irtt" version
 
-      - name: Build irtt-rs CLI
-        run: cargo build -p irtt-cli --locked
+      - name: Build irtt-rs client
+        run: cargo build -p irtt-rs --bin irtt-client --locked
 
       - name: Run netem interop comparisons
         run: |
@@ -55,21 +56,21 @@ jobs:
             --all \
             --skip-build \
             --upstream-irtt "$GOBIN/irtt" \
-            --irtt-rs-command "$PWD/target/debug/irtt-cli"
+            --irtt-rs-command "$PWD/target/debug/irtt-client"
 
       - name: Append netem interop summary
         if: always()
         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@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # 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/release.yml
-          shellcheck: false
   zizmor:
     name: zizmor
     runs-on: ubuntu-latest
@@ -56,11 +28,17 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
         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@192e21d79ab29983730a13d1382995c2307fbcaa # v0.5.7
+        uses: zizmorcore/zizmor-action@85b2b9fb8e3325e7a23d7d0a9d7ba5ae0f999e3e # v0.7.1
         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/irtt-rs-release.yml

@@ -42,7 +42,7 @@ on:
   pull_request:
   push:
     tags:
-      - '**[0-9]+.[0-9]+.[0-9]+*'
+      - 'irtt-rs**[0-9]+.[0-9]+.[0-9]+*'
 
 jobs:
   # Run 'dist plan' (or host) to determine what tasks we need to do

.github/workflows/osv-scanner.yml

@@ -3,8 +3,7 @@
 # separate terms of service, privacy policy, and support
 # documentation.
 
-# A sample workflow which sets up periodic OSV-Scanner scanning for vulnerabilities,
-# in addition to a PR check which fails if new vulnerabilities are introduced.
+# Scan all dependencies on main and compare newly introduced vulnerabilities on PRs.
 #
 # For more examples and options, including how to ignore specific vulnerabilities,
 # see https://google.github.io/osv-scanner/github-action/
@@ -20,6 +19,7 @@ on:
     - cron: "45 8 * * 1"
   push:
     branches: ["main"]
+  workflow_dispatch:
 
 permissions:
   # Require writing security events to upload SARIF file to security tab
@@ -29,21 +29,12 @@ permissions:
   actions: read
 
 jobs:
+  # Both pinned workflows default to a recursive scan of ./, including fuzz/.
+  # OSV v2 excludes the root Git repository unless --include-git-root is set;
+  # the old --skip-git flag is no longer supported.
   scan-scheduled:
-    if: ${{ github.event_name == 'push' || github.event_name == 'schedule' }}
-    uses: "google/osv-scanner-action/.github/workflows/osv-scanner-reusable.yml@9a498708959aeaef5ef730655706c5a1df1edbc2" # v2.3.8
-    with:
-      # Example of specifying custom arguments
-      scan-args: |-
-        -r
-        --skip-git
-        ./
+    if: ${{ github.event_name == 'push' || github.event_name == 'schedule' || github.event_name == 'workflow_dispatch' }}
+    uses: "google/osv-scanner-action/.github/workflows/osv-scanner-reusable.yml@b1d267aea5211fa648d9d442fa64b90dbdcbdd36" # v2.7.0
   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@9a498708959aeaef5ef730655706c5a1df1edbc2" # v2.3.8
-    with:
-      # Example of specifying custom arguments
-      scan-args: |-
-        -r
-        --skip-git
-        ./
+    uses: "google/osv-scanner-action/.github/workflows/osv-scanner-reusable-pr.yml@b1d267aea5211fa648d9d442fa64b90dbdcbdd36" # v2.7.0

.github/workflows/rust-clippy.yml

@@ -24,12 +24,12 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
         with:
           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@54f647b7e1bb85c95cddabcd46b0c578ec92bc1a # v4
+        uses: github/codeql-action/upload-sarif@6f2ac81f5cd81fe351a197ba0b00d91d03cd2aee # v4
         if: always()
         with:
           sarif_file: rust-clippy-results.sarif

.github/workflows/semver.yml

@@ -1,27 +0,0 @@
-name: Semver
-
-on:
-  workflow_dispatch:
-  push:
-    tags:
-      - "v*.*.*"
-
-permissions:
-  contents: read
-
-jobs:
-  semver:
-    name: cargo-semver-checks
-    runs-on: ubuntu-latest
-    timeout-minutes: 20
-
-    steps:
-      - name: Checkout
-        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # 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@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7
-        with:
-          persist-credentials: false
-
-      - name: Run cargo-deny
-        uses: EmbarkStudios/cargo-deny-action@bb137d7af7e4fb67e5f82a49c4fce4fad40782fe # 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@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # 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/release.yml
-          shellcheck: false

AGENTS.md

@@ -0,0 +1,206 @@
+# Repository guidance
+
+Repository-wide guidance for contributors and coding agents working on `irtt-rs`.
+Before editing, also check for a more specific `AGENTS.md` in the target subtree.
+
+## Clean-room boundary
+
+`irtt-rs` is an independent Rust implementation of an IRTT-compatible protocol stack. It began as a clean-room client reimplementation and now contains project-specific architecture and behavior beyond that original compatibility baseline.
+
+- Do not inspect, quote, copy, translate, or derive implementation details from upstream `heistp/irtt` source code or upstream tests.
+- Do not use contaminated notes or source-derived pseudocode as implementation input.
+- Use the local clean-room specification, black-box verification artifacts, current `irtt-rs` code, and current tests.
+- Black-box interoperability testing against an installed upstream `irtt` binary is allowed when relevant. Treat it as an external implementation, not source material.
+- If behavior remains ambiguous, state the ambiguity instead of guessing or consulting upstream implementation code.
+
+Compatibility and interoperability references:
+
+- `docs/protocol/IRTT_CLIENT_PROTOCOL_SPEC.md` — verified client-side
+  compatibility baseline.
+- `docs/protocol/IRTT_SERVER_PROTOCOL_SPEC.md` — verified server-side
+  compatibility baseline.
+- `docs/protocol/BLACKBOX_VERIFICATION_REPORT.md` — black-box evidence and
+  corrections supporting both the client and server baselines.
+- `docs/protocol/test-vectors/README.md` — captured client-facing packet
+  vectors.
+- `docs/protocol/test-vectors/SERVER_BEHAVIORAL_VECTORS.md` — black-box
+  server behavioral vectors, edge cases, and session behavior.
+- `docs/protocol/captures/` — packet captures referenced by the verification
+  report and behavioral vectors. Behavioral vectors and captures are
+  evidence/artifacts, not architecture prescriptions.
+- `docs/INTEROP_COMPARISON.md` — procedures for black-box comparison against
+  the upstream `irtt` executable.
+- `docs/clean-room/CLEANROOM_NOTES.md` — provenance only; not a normative
+  protocol specification.
+
+The verified client spec predates later `irtt-rs` architecture and project-specific features. Its scope statements, including server implementation being out of scope, describe that document's scope and are not permanent repository restrictions.
+
+For compatibility questions, the verified spec and black-box observations define the baseline. For `irtt-rs`-specific APIs, runtime architecture, resource bounds, and later features, current code and current project documentation are authoritative.
+
+## Architecture
+
+Main boundary:
+
+> `irtt-proto` — wire semantics shared by client/server. `irtt-client` — client/session behavior. `irtt-server` — server/session behavior and Tokio runtime/orchestration. `irtt-stats` — statistics over client-facing events/results as currently designed. `irtt-rs` (application package, `crates/irtt-app`) — presentation/orchestration.
+
+- `irtt-proto`: pure protocol encoding/decoding, flags, layouts, params, varints/zigzag, HMAC-MD5, validation. No sockets, runtimes, lifecycle, stats, or presentation.
+- `irtt-client`: socket/session lifecycle, negotiation, probe send/receive, timing metadata, classification, bounded state, and events.
+  - `Client`: runtime-free blocking/manual adapter.
+  - `AsyncClient`: optional Tokio low-level adapter.
+  - `ManagedClientTask` / `ManagedClientHandle`: unified Tokio managed driver/control surface.
+  - `BlockingManagedClient`: synchronous owner using a dedicated current-thread Tokio runtime.
+- `irtt-server`: exists; see "Server architecture (`irtt-server`)" below.
+- `irtt-stats`: cumulative/rolling/finite statistics over client events. No wire/session state machine logic.
+- `irtt-rs` (application package, `crates/irtt-app`): argument parsing, managed orchestration, output, summaries, TUI, server applet orchestration, diagnostics, and exit behavior. Produces the `irtt-rs` multicall dispatcher plus the dedicated `irtt-client`, `irtt-tui`, and `irtt-server` binaries. Do not duplicate protocol/session state machines here.
+
+Tokio must remain optional for `irtt-client`; default builds must remain runtime-free and Tokio-free unless an explicit architectural change says otherwise. This rule is specific to `irtt-client` — do not generalize it to `irtt-server`, which has the opposite policy below.
+
+### Server architecture (`irtt-server`)
+
+`irtt-server` is a first-class reusable server crate. It contains the deterministic OPEN/ECHO/session core — packet admission, authentication policy, open negotiation, the bounded session table, open reply construction, echo processing with its per-session receive state and timestamps, per-session rate limiting, session lifetime with idle expiry, the maximum-duration server-initiated close, and client-initiated close — plus a reusable Tokio UDP `Server` that runs one sequential `ServerCore` per listener with caller-controlled shutdown and scheduled idle maintenance. Logical expiry remains exact on authenticated, structurally valid requests, while the runtime also reclaims expired sessions once per second when no traffic arrives. Each reply carries the raw traffic class it must be sent with, which the runtime applies to the listener before every send. A wildcard listener additionally recovers each request's local destination from packet metadata and sends that request's reply from it, on Linux, macOS and FreeBSD; a wildcard bind on a target without that path is refused at construction rather than served from a routing-table source address. Explicit-address listeners are unaffected everywhere. Echo replies fill their payload from the session's negotiated server fill; the policy and its deliberate divergences are in `crates/irtt-server/AGENTS.md`. Two optional negotiation policies restrict what a session may ask the server to provide — a timestamp allowance and DSCP permission — both off by default and both settled during open negotiation rather than in the runtime. Above that one-listener primitive sits `ServerSet`, the service-level owner of one or more independent `Server`s: it binds them all or none, runs each in its own Tokio task, fans one external shutdown out to them, joins them all, and fails the group if any listener fails or stops early. Ordinary process-level polish and observability decisions are what remains of the server architecture.
+
+- It shares wire semantics with the client through `irtt-proto` and follows the same clean-room boundary.
+- It must **not** depend on `irtt-client` merely to reuse protocol behavior.
+- Unlike `irtt-client`, the server has no product requirement to remain runtime-free: `irtt-server` is intentionally **Tokio-native**, and Tokio does not need to be optional for it.
+- There is currently no requirement for a blocking server API, alternate async runtimes, a runtime abstraction layer, or a runtime-free server feature. Do not build blocking/runtime variants merely for symmetry with the client, and do not invent a mirrored client-style API family (`BlockingServer`, `AsyncServer`, `ManagedServer`, `BlockingManagedServer`, or similar) ahead of agreement.
+- Protocol/session logic should be separated from socket/runtime orchestration where that materially improves deterministic testing, ownership clarity, state-machine reasoning, or maintainability. A `ServerCore`-like internal boundary is therefore desirable, but its exact name/API is not prescribed, it need not be public, it is not a promise of runtime independence, and simple code should not be tortured merely to make the core artificially pure.
+- Runtime/server orchestration belongs around that core and may freely use Tokio for UDP sockets, `recv_from`/`send_to`, IPv4/IPv6 listeners, timers, session expiry, max-duration deadlines, shutdown, bounded control/config channels where useful, and `select!`-style orchestration.
+- Ownership is layered and the layers do not blur: `Server` is the one-listener primitive (one socket, one `ServerCore`, one sequential loop), and `ServerSet` supervises one or more of them without owning protocol or session state itself. A common `ServerConfig` is cloned into each listener, so its bounds — `max_sessions` included — are per listener and not per process. Listeners share nothing else: no shared `ServerCore`, no global session table or token namespace, no shared clock, and one sequential sender per socket, which is what keeps the socket-wide reply traffic class race-free.
+- The server applet exists behind the `irtt-rs` application package's `server` feature, which is part of that crate's default build. It is thin orchestration/configuration over reusable `irtt-server` — one current-thread Tokio runtime, one repeatable `--bind`, one `ServerSet` — and must not grow a second server state machine. **It always uses `ServerSet`, including for a single bind**: there is no direct CLI-to-`Server` path and no bind-count branch, so startup, shutdown and listener-failure semantics are identical whatever was configured, and the singleton case exercises the same orchestration in normal use. Hostname resolution, interface expansion, daemonization, and configuration files are deliberately absent.
+- Resource policy: the server should use bounded session/resource policy. Upstream's observed lack of useful default session/per-peer bounds, and its never expiring a session that has not carried an echo request (see `IRTT_SERVER_PROTOCOL_SPEC.md`), are not interoperability requirements and must not be reproduced merely for compatibility.
+- Testing: prefer `irtt-server` for normal compliant fake-peer behavior where practical, as far as its implemented behavior reaches. Keep narrow adversarial/raw peers for intentionally malformed, ambiguous, or non-compliant wire behavior.
+
+## Engineering rules
+
+- Make the smallest coherent change that solves the requested problem.
+- Avoid unrelated cleanup and speculative abstractions.
+- Preserve public API and wire behavior unless the task explicitly changes them.
+- Treat resource bounds, wake behavior, blocking, cancellation, cleanup, and lifecycle termination as correctness concerns in long-running code.
+- Keep fallible preparation before irreversible side effects where transaction semantics require it.
+- Do not suppress compiler or Clippy warnings merely to make checks green.
+- If an apparent defect may encode an intentional design decision, inspect surrounding code/docs/history and ask rather than silently redesigning it.
+
+## Testing policy
+
+Tests protect durable behavior, compatibility, and important invariants. They do not exist to maximize test count or coverage percentage. Tests are maintained repository code: every persistent test adds review, CI, refactoring, and maintenance cost, so it must justify that cost.
+
+### Test at the owning layer
+
+Prefer production interfaces and component/integration tests at the lowest architectural layer that owns the complete behavior. Higher-level or process-level is not inherently better.
+
+- `irtt-proto`: wire formats, codecs, validation, malformed input, and protocol boundaries.
+- `irtt-client`: client/session behavior, multi-target orchestration, burst/staggered pacing, scheduling, lifecycle, managed events, and target updates.
+- `irtt-server`: server/session behavior and server runtime/orchestration.
+- `irtt-stats`: statistics, loss/IPDV accounting, rolling windows, and retention bounds.
+- `irtt-rs` / `irtt-app`: behavior introduced by the application layer itself, such as argument-to-config mapping, presentation/formatting, app-specific diagnostics/exit policy, and genuine process/signal behavior.
+
+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.
+
+One strong behavioral test through a normal production interface is usually better than several tests of private helpers or reconstructed internals. Be especially skeptical of unit tests that depend on private functions, methods, structs, fields, or implementation sequence: harmless internal refactors should not require test rewrites.
+
+Avoid tests that primarily:
+
+- assert private representation or historical implementation details;
+- mirror implementation steps or exercise branches solely for coverage;
+- duplicate stronger coverage at another layer;
+- pin exact human-readable wording unless that wording is itself contractual;
+- test standard-library/dependency behavior;
+- use subprocess machinery or test-only observability when the owning crate exposes the behavior directly.
+
+If a component/integration test through the owning crate's normal API protects the same durable behavior, prefer it unless a focused unit test materially improves precision, diagnosis, or coverage of a hard-to-observe invariant.
+
+### Unit tests where they earn it
+
+Focused unit/table-driven tests are appropriate for stable pure or algorithmic behavior, especially protocol codecs/vectors, statistics formulas, hand-rolled data structures, and resource/liveness invariants that cannot be observed reliably from a higher-level production interface.
+
+### Temporary implementation tests
+
+Temporary narrow tests are welcome while implementing/debugging a change to prove a hypothesis, reproduce a bug, or exercise a difficult state transition. Remove or consolidate them before finalizing unless they independently protect a durable regression or invariant.
+
+### Resource/liveness tests and hooks
+
+Direct low-level tests and test-only counters are justified when the invariant is otherwise not observable, e.g. bounded work per poll, no starvation/eventual progress, avoiding an otherwise O(n) hot-path operation, or exact cancellation/stop/update linearization.
+
+Assert the invariant rather than the current mechanism used to achieve it. Prefer “bounded work and eventual progress” over a specific private cursor value when another fair implementation would also be valid.
+
+`#[cfg(test)]` fault injection is acceptable for conditions that cannot be produced reliably through normal interfaces, such as socket-option failures, short sends, false readiness, exact cancellation points, sequence wrap, or race linearization. Do not add test-only production hooks solely for convenient observability.
+
+### Fake peers and interoperability
+
+Use production protocol encoders/decoders for compliant fake peers. Do not maintain shadow packet encoders in tests unless intentionally constructing malformed wire data.
+
+Prefer a real `irtt-server` for normal compliant behavior once available; keep small adversarial peers for behavior a compliant server should not produce.
+
+Cross-implementation tests are especially valuable because two `irtt-rs` endpoints can otherwise agree on the same mistake.
+
+When compatibility is in question, prefer black-box interoperability testing
+against an upstream `irtt` executable where practical. Follow
+`docs/INTEROP_COMPARISON.md` and treat upstream only as an external executable;
+do not inspect its source or tests.
+
+### Synchronization and timing
+
+Prefer synchronization on actual events/state over sleeps or tiny wall-clock windows.
+
+- Use channels, condvars, packet gates, or equivalent deterministic signals with bounded failure timeouts.
+- Sleeps are fine when oversleeping cannot invalidate correctness; do not sleep merely hoping another thread/process finished work.
+- Avoid wall-clock assertions that include process spawn or unrelated setup time.
+- Condition-wait loops must be bounded and fail with a useful diagnostic rather than hang.
+
+When a test fails after a legitimate implementation change, determine whether production regressed or the harness encoded an invalid assumption. Do not change correct production behavior merely to satisfy a brittle test.
+
+## Workflow and verification
+
+For non-trivial work:
+
+1. Inspect relevant code, tests, and local protocol/design references.
+2. Identify the externally meaningful contract or internal invariant.
+3. Make a short plan for multi-file or subtle lifecycle/state changes.
+4. Implement the smallest coherent patch.
+5. Run focused verification while iterating.
+6. Review the final diff for accidental scope, brittle tests, and unnecessary test hooks.
+7. Run broader verification appropriate to the risk.
+
+Skip planning ceremony for tiny obvious edits. Do not add unrelated tests, abstractions, docs, or refactors merely because they are nearby.
+
+Use the narrowest useful checks first. For substantive workspace changes, final verification should normally include:
+
+```sh
+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
+```
+
+Also verify `--no-default-features` when changing feature gates, optional dependencies, runtime boundaries, or code intended to build without Tokio.
+
+Interop tests require an external `irtt` binary and should only run when the task concerns interoperability or explicitly requests them. Do not run repetition loops, fuzzing, Miri, Loom, mutation testing, or similar expensive checks as routine ceremony.
+
+Never claim a command passed unless it actually ran successfully.
+
+## Repository hygiene
+
+- Do not use destructive Git operations unless explicitly requested.
+- Do not push, force-push, create/update a PR, or rewrite unrelated history unless explicitly requested.
+- Keep commits scoped to the requested work and preserve unrelated local changes.
+
+## Completion
+
+Report concisely:
+
+1. what changed;
+2. verification actually run and its result;
+3. meaningful tests added/updated/consolidated/removed, with justification for each persistent test added or materially expanded;
+4. remaining risks, ambiguities, or follow-ups.
+
+Do not produce a giant changelog of incidental edits.

CHANGELOG.md

@@ -0,0 +1,321 @@
+# Changelog
+
+This project's crates are versioned independently. Each release below is
+scoped to a single crate and tagged as `<crate>/vX.Y.Z` (see
+[Releasing](#releasing) below).
+
+All notable changes to each crate are documented in its own section per
+release. The format is loosely based on
+[Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
+
+## 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
+
+- New server-direction wire codecs: `decode_open_request`, `encode_open_reply`, `decode_echo_request`, `encode_echo_reply`, and `decode_close_request`, so a server implementation (now `irtt-server`) can encode/decode the same wire format the client side already used, instead of duplicating protocol logic outside this crate.
+- New `ProtoError` variants `MissingField` and `UnexpectedField` for structural validation of optional fields that must be present/absent together.
+
+#### Changed
+
+- `encode_echo_request` (and the request-side echo codec generally) now takes the negotiated params as a separate argument rather than bundling them into `EchoRequest` — a breaking signature change for any direct caller of the proto-level echo encoder.
+- `ProtoError::NegativePacketLength` was renamed to `ProtoError::PacketLengthUnrepresentable { length: i64 }`, reflecting that the check now rejects any length that doesn't fit the wire representation, not only negative ones — a breaking rename for callers matching on this variant.
+
+#### Compatibility
+
+- The echo-reply length codec now accepts upstream `irtt`'s longer midpoint-echo compatibility length instead of rejecting it, fixing an interop gap against real upstream servers/clients that send that length.
+
+## irtt-client
+
+### 0.6.0
+
+#### Added
+
+- Added `ManagedClientHandle::subscribe_status()` and `ManagedStatusSubscription` for observing durable lifecycle and completion state independently of the lossy event stream. The current snapshot is immediately readable, change notifications track subsequent updates, and terminal target status includes its completed outcome.
+- Managed targets can override the shared address-family policy while retaining the original hostname for resolution on each new generation.
+
+#### Changed
+
+- `ClientConfig` is now reusable across endpoints: `Client::connect` and `AsyncClient::connect` take the endpoint separately, with configuration grouped into `socket`, `request` (`SessionRequest`), and `open` (`OpenPolicy`). `AddressFamily` replaces the separate socket family flags, and blocking receive timeouts are configured through `Client::set_recv_timeout`.
+- Explicit `Authentication`, `HmacKey`, and managed `TargetAuth` replace `ClientConfig.hmac_key` and `ClientAuthConfig`. Key bytes are shared across clones and redacted from debug output. Switching between inherited and explicit authentication or address-family settings starts a new target generation, even when the effective settings are equal.
+- `NegotiationResult` replaces `NegotiatedParams`, separating typed `AcceptedSessionParameters` from exact peer-returned wire parameters and accepted `NegotiationChange` records (formerly `NegotiationRestriction`). Open outcomes and lifecycle events now use tuple variants carrying `SessionStarted` or `NoTestCompleted` payloads.
+- Low-level clients now leave probe cadence and run duration entirely to the caller. `next_send_deadline` and `is_run_complete` were removed; managed clients continue to provide scheduling and finite-run completion. Low-level callers can inspect `negotiation()`, `has_pending_probes()`, and `next_probe_timeout_deadline()` to drive their own event loop.
+- Probe sends now return `Result<SendReceipt, SendProbeError>`, distinguishing failures before socket acceptance from failures after a probe was committed. Receipts convert to `ClientEvent::EchoSent`; its `scheduled_at` and `timer_error` fields are now optional and absent for low-level sends.
+- Stop receipts resolve when the stop request is durably observed or the task becomes terminal; callers must still await task completion to observe finished cleanup.
+
+#### Fixed
+
+- Finite managed runs now reach their negotiated end under socket backpressure, even when no pending probe timeout remains to wake the driver. Staggered pacing no longer repeatedly wakes idle or draining targets that have no send deadline.
+- Blocking receive operations now return lifecycle errors immediately when no session is open, instead of blocking for a datagram or returning empty success after a timeout.
+
+#### Performance
+
+- Managed drain-deadline lookup no longer scans retained timed-out probes, keeping lookup work bounded as retained probe state grows.
+
+#### Compatibility
+
+- The configuration, authentication, negotiation, lifecycle-event, and send APIs above are breaking changes without compatibility aliases. Low-level callers must enforce their own cadence and duration or use a managed client.
+- `AcceptedSessionParameters::dscp` is a six-bit codepoint; `NegotiationResult::peer_params.dscp` remains the raw traffic-class byte. Accepted durations and intervals use Rust duration types rather than wire nanosecond integers.
+- Tokio remains optional, and the default client build remains runtime-free. These API changes do not introduce a wire-protocol migration.
+
+### 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
+
+- New optional `tokio` Cargo feature adding `AsyncClient`, a low-level non-blocking/poll-based Tokio adapter alongside the existing runtime-free blocking `Client`.
+- New managed driver stack built on top of `AsyncClient`: `ManagedClientTask` / `ManagedClientHandle` (a unified Tokio-based managed driver and control surface, supporting dynamic per-target updates to a running session group) and `BlockingManagedClient` (a synchronous owner that runs a dedicated current-thread Tokio runtime internally). This replaces the project's earlier managed-client design outright rather than extending it, including changes to the `ClientError` variants it can surface.
+- Linux kernel receive-timestamp capture (`SO_TIMESTAMPING`-family ancillary data) feeding one-way-delay (OWD) calculations, and equivalent kernel transmit-timestamp capture on the send side, materially improving OWD accuracy over the previous best-effort user-space send/receive timestamps on Linux. Both require the `ancillary` feature.
+
+#### Fixed
+
+- DSCP wire semantics: the negotiated DSCP value was being shifted twice on the wire path (double-application of the ECN/DSCP bit layout), which produced an incorrect traffic-class byte in some configurations; the client-side DSCP handling was reworked to apply the shift exactly once and is covered by expanded DSCP/negotiation tests.
+- Post-send timestamp capture correctness fix so the locally-recorded send timestamp used for OWD/RTT calculations reflects when the probe actually left the socket rather than a timestamp that could be skewed by scheduling between encode and send.
+- A batch of managed-session liveness and lifecycle fixes: dynamic target groups no longer spin instead of blocking while idle; empty dynamic groups stay idle correctly; peer-initiated closes are now recorded and surfaced (including counters/provenance) instead of being silently dropped or racing with correlation; authenticated close is honored ahead of reply correlation; terminal outcomes are now published for targets that fail rather than being dropped silently; completed event hubs are sealed and completed-target retention is bounded (preventing unbounded growth in long multi-target runs); missed probe slots are skipped rather than mis-scheduled; dropped-subscription events are now exposed to consumers instead of being swallowed; and a timeout-budget bug in the managed opening phase was corrected.
+- Linux receive paths (blocking `Client::open`/`recv_once`/`recv_available`, `AsyncClient`'s non-blocking recv/open polling, and the MSG_ERRQUEUE TX-timestamp drain) now retry transparently on `EINTR` instead of surfacing it as a fatal socket error, while preserving each path's existing timeout/deadline contract (no retransmit, no timeout extension under repeated interruption).
+- `ClientError` failure classification was made exhaustive/more precise, giving callers a fuller and more accurate error taxonomy to match on instead of a catch-all in some paths.
+
+#### Compatibility
+
+- The `ancillary` (Linux socket ancillary-data) feature was hardened to only perform safe operations, closing a soundness gap in how ancillary control-message buffers were handled.
+
+## 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
+
+- New public `address_family_available()` helper (re-exported from `set`), for probing whether an address family can actually bind locally rather than merely constructing a socket for it. Used by the `irtt-rs` server applet to distinguish a genuinely unsupported address family from an ordinary bind failure when falling back from its default dual-family bind.
+
+### 0.5.0
+
+#### Added
+
+- `irtt-server` is a new first-class, reusable crate this release, built from scratch: a deterministic `ServerCore` handling OPEN/ECHO/CLOSE packet admission, authentication policy, open negotiation, a bounded session table, echo processing with per-session receive state and timestamps, per-session rate limiting, session lifetime with idle expiry, server-initiated close on maximum duration, and client-initiated close.
+- A reusable Tokio UDP `Server` runs one sequential `ServerCore` per listener with caller-controlled shutdown and once-per-second scheduled idle-session maintenance (in addition to exact logical expiry on authenticated, structurally valid requests). `ServerSet` sits above it as the service-level owner of one or more independent `Server`s: it binds them all-or-none, runs each in its own Tokio task, fans one external shutdown signal out to all of them, joins them, and fails the group if any listener fails or stops early — enabling multi-listener deployments from a single `ServerConfig`.
+- Each reply now carries the raw traffic class it must be sent with, applied to the listener socket immediately before every send.
+- Wildcard listeners recover each request's local destination from packet ancillary metadata and send that request's reply from the same address, on Linux, macOS, and FreeBSD. `Server::from_socket`/`Server::bind` are now fallible specifically because of this: a wildcard bind on a platform without that path is refused at construction (`ServerRuntimeError::WildcardSourceSelectionUnsupported`) rather than silently served from a routing-table-chosen source address. Explicit-address listeners are unaffected on all platforms.
+- Configurable echo-reply payload fill policy (`ServerFill`), controlling what bytes a session's echo replies are padded with.
+- Two optional negotiation policies, both off by default and settled during open negotiation: a timestamp allowance and a DSCP permission, restricting what a session may ask the server to provide.
+- Linux kernel receive-timestamp capture for inbound packets, feeding more accurate server-side timing metadata, mirroring the equivalent client-side capability added in `irtt-client`.
+
+#### Fixed
+
+- The DSCP/traffic-class byte applied to replies was corrected to match the client-side wire-semantics fix (see `irtt-client`), so server-echoed DSCP marking is now consistent with what clients expect.
+- Executable-params validation on OPEN requests was tightened so malformed/contradictory negotiated parameters are rejected during open negotiation rather than accepted and mishandled later.
+- Packet-length policy corrected so oversized/invalid negotiated lengths are rejected consistently with the updated `irtt-proto` length validation.
+- A receive-drop/backpressure policy fix for malformed or unauthenticated inbound packets, preventing them from disrupting the session table or other in-flight sessions.
+- A receive-timestamp "wall clock" fix on the kernel RX-capture path, and a 32-bit (i686) `timespec` conversion correctness fix covered by a dedicated regression test.
+- The server's ancillary receive loop now retries transparently on `EINTR` instead of terminating the listener, matching the equivalent `irtt-client` fix.
+
+#### Compatibility
+
+- Resource bounds are enforced by design (bounded session table, per-listener `max_sessions`, rate limiting, idle/max-duration expiry) rather than mirroring upstream `irtt`'s effectively unbounded session/per-peer behavior; this is a deliberate divergence, not an oversight, and is documented in `crates/irtt-server/AGENTS.md`.
+
+## irtt-stats
+
+### 0.5.2
+
+#### Changed
+
+- `TimeStats` is now re-exported from `measurement-stats`, retaining the existing `irtt_stats::TimeStats` import path, fields, and methods.
+- Timer-error statistics now omit sends without scheduling metadata instead of recording an artificial measurement.
+
+#### Fixed
+
+- Time-based rolling windows now expire backdated events correctly, including expired events inside retained arrival history. Older timestamps cannot move the expiry anchor backwards or restore expired history.
+- Rolling upstream and downstream loss now use the server receive-count increase over the retained packet-event interval instead of comparing window counts against a cumulative server count.
+- Rolling directional-loss estimates are unavailable when counter observations are missing, stale, discontinuous, or separated by an interior gap in the time window, rather than reporting misleading values.
+
+#### Performance
+
+- Indexed rolling-window expiry avoids full-window scans on insertion and reclaims expired entries without accumulating tombstones.
+
+#### Compatibility
+
+- This release consumes `irtt-client` 0.6 events; applications using both crates must upgrade them together.
+- Unavailable rolling directional-loss packet estimates are `None`; their percentage fields remain `0.0`. Valid signed estimates remain possible, and raw server receive counts retain their cumulative meaning.
+- Time-based rolling windows expire when new events arrive, retain events exactly at the cutoff, and have no event-count cap. Use `rolling_count` when event storage needs a fixed bound.
+
+### 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
+
+- Exact median calculation for `send_call`, `timer_error`, and `server_processing` event-duration statistics, which previously always reported `None` for these medians instead of a computed value.
+
+#### Added
+
+- `LateReplyMode` (`Measure` / `CountOnly`) lets a consumer choose whether replies that arrive after their probe is considered late are still fully measured into the running statistics or only counted, without affecting the other samples.
+- `StatsConfig::estimated_retained_bytes(probe_count)` gives callers an API to estimate the memory a stats configuration will retain for a given probe count, ahead of actually running a session (used by `irtt-cli`'s multi-target memory-usage warning, see below).
+
+## irtt-rs
+
+### 0.8.0
+
+#### Added
+
+- Added mutually exclusive `-4` / `--ipv4`, `-6` / `--ipv6`, and `--dual-stack` options to the client and TUI. Dual-stack hostnames expand into independent `/v4` and `/v6` targets with separate sessions, statistics, and failures; explicit IP literals remain single targets.
+- Continuous TUI runs now reconnect independently after target failures, peer closure, or server-limited session completion while healthy targets continue uninterrupted. The TUI remains running even when every target fails.
+- Added target selection and a scrollable details sheet showing negotiation, counters, timing statistics, warnings, and recent events.
+- Graph axes now display local wall-clock timestamps, including fractional seconds or dates where appropriate.
+
+#### Changed
+
+- Replaced separate Graph and Dashboard views with one dashboard comparing all targets. Target rows show effective RTT, cumulative loss, jitter, and the age of the last primary reply. `Tab` / `Shift-Tab` selects a target; `d` opens details, with `g` retained as an alias.
+- Reconnecting targets retain their logical row and graph history, reset session statistics for each new generation, and leave gaps between generations.
+- Increased graph retention from 100,000 to 500,000 samples per target and extended the maximum graph window from one hour to 24 hours.
+- Clearing graph history now clears all targets and returns to live view while preserving latest samples and statistics.
+- Client and TUI frontends now react asynchronously to measurements, status changes, input, and shutdown, removing periodic polling delays.
+- The application library's `run_stream`, `run_tui`, and `prepare_managed_run` entry points are now asynchronous.
+
+#### Performance
+
+- Graph rendering selects samples within the visible viewport instead of scanning the full retained history, with interpolation at viewport boundaries.
+- Reduced graph-history memory usage per sample substantially, allowing retention to increase from 100,000 to 500,000 samples per target without proportional memory growth.
+- Increased regular TUI refresh frequency to 100 ms for smoother updates.
+
+#### Compatibility
+
+- Automatic reconnect applies to continuous TUI runs, not ordinary `irtt-client` runs or finite TUI runs. Explicit stops and no-test completion do not trigger retries.
+- Dual-stack expansion changes target labels and can double probe traffic per hostname. The stdin limit of 128 desired targets applies after expansion; generated labels must remain unique.
+- Address families are discovered when a declaration is added. Each new session resolves the original hostname within its assigned family; newly appearing families are not added automatically. Unchanged stdin declarations retain their discovered families, while removal and re-addition performs fresh discovery.
+- New stdin declarations are prepared asynchronously while existing measurements continue. Preparation errors stop the stream gracefully without applying a partial target set.
+- The larger graph cap permits higher eventual memory use: approximately 42 MiB per target for retained graph samples at the cap on 64-bit macOS, excluding statistics and rendering buffers.
+- Application-library callers must await client/TUI run and preparation functions and supply the new shutdown argument to the run functions.
+- `ClientArgs::prepare` and `TuiArgs::prepare` are also asynchronous; `TargetPreparation::prepare` replaces `prepare_managed_targets`, and `parse_stdin_target_set` now returns `TargetSpec` values for preparation.
+- The application's former `TargetAuth` type was replaced by `irtt_client::managed::TargetAuth`.
+- The public output wrappers `EventRenderStats` and `IpdvPair` were removed in favor of `irtt_stats::EventStatsUpdate` and `IpdvPairUpdate`.
+- `DEFAULT_RECV_TIMEOUT`, `is_shutdown_requested`, and `TuiArgs::timestamp_mode` were removed. `install_signal_handler` is now available only with the `server` feature; client/TUI embedding uses `install_async_signal_handler`.
+- MSRV remains Rust 1.88. Existing output column names and formats are preserved.
+
+### 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
+
+- The `irtt-server` applet now has sensible zero-argument defaults: with no `--bind`, it binds the wildcard IRTT port on both address families (`[::]:2112` then `0.0.0.0:2112`) instead of requiring an explicit address, on platforms where wildcard reply-source selection is supported. Any explicit `--bind` fully replaces the default pair rather than adding to it.
+
+#### Changed
+
+- If one of the two default listeners fails because its address family has no local support on the host (e.g. IPv6 administratively disabled on an otherwise IPv4-capable host), the server now falls back to serving just the surviving family instead of failing outright. Any other failure reason (port in use, permission denied, no safe wildcard reply-source path) still fails startup as it would for an explicit `--bind`.
+
+### 0.6.0
+
+#### Changed
+
+- The application Cargo package was renamed from `irtt-cli` to `irtt-rs`, moving to `crates/irtt-app`. This is the application distribution package that produces the `irtt-rs`, `irtt-client`, `irtt-tui`, and `irtt-server` binaries; it is unrelated to the reusable `irtt-client` library crate, which keeps its existing name and version.
+- The `irtt-cli` executable was hard-renamed to `irtt-client` to avoid reading as an umbrella CLI now that the application also ships a first-class server. There is no `irtt-cli` compatibility binary or alias.
+- Dedicated binaries now have role-specific entry points (`irtt-client`, `irtt-tui`, `irtt-server`) instead of all funneling through the multicall dispatcher's argv0/subcommand logic. Each dedicated binary always runs its own role regardless of the name it is invoked or copied under, and no longer links code for the other applet roles it doesn't implement. The `irtt-rs` binary remains the feature-selectable multicall dispatcher and is the only binary that inspects argv0 or subcommands.
+- Future application releases move to the `irtt-rs/vX.Y.Z` tag namespace (previously `irtt-cli/vX.Y.Z`); see [Releasing](#releasing).
+
+## irtt-cli
+
+### 0.5.0
+
+#### Added
+
+- A new `server` applet (the `irtt-server` binary and `irtt-rs server` subcommand), gated behind the `server` Cargo feature which is now part of `irtt-cli`'s default feature set. It is thin orchestration over the new `irtt-server` crate: one current-thread Tokio runtime, one repeatable `--bind`, and `ServerSet` for startup/shutdown/listener-failure handling — including for a single bind.
+- Positional `[LABEL=]TARGET` argument syntax for specifying client targets.
+
+#### Changed
+
+- Target specification moved from a `--target LABEL=TARGET` flag to plain positional `[LABEL=]TARGET` arguments — a breaking CLI syntax change for any script invoking targets via the old flag.
+- The `Target` column is now always present in default, CSV, TSV, and JSONL output, rather than only appearing once more than one target was specified. This is a breaking output-format change for scripts that parsed single-target output and assumed no `Target` column.
+- Cargo feature flags were simplified: the separate `stats`, `full`, and `client-runtime` features were removed, and statistics support is now mandatory whenever the `client` (or `tui`) feature is enabled, rather than optional. Consumers building with `--no-default-features` and selectively re-enabling a `stats` or `client-runtime` feature will need to update their feature selection.
+- The stats-related memory-usage warning now scales with the number of configured targets (using `irtt-stats`'s new `estimated_retained_bytes`), instead of assuming a single target's worth of retained memory.
+
+#### Fixed
+
+- Single-target runs are now driven through the same `ManagedClient` path as multi-target runs, instead of a separate single-target code path, fixing behavioral drift between the two (e.g. continuous single-target runs now stop correctly on peer-initiated close and multi-target failures are now reported with a nonzero exit status).
+- Continuous (unbounded-duration) runs, both single- and multi-target, now stop and report correctly when the peer closes the session, instead of hanging or exiting silently.
+- The TUI's input-event draining is now bounded per tick, fixing a starvation/liveness issue where a burst of input could stall rendering or probe scheduling.
+- The TUI's live graph history buffer is now allocated lazily instead of eagerly, avoiding unnecessary upfront allocation for graphs that are never shown.
+- A managed-session terminal-state reconciliation fix in the CLI's use of the managed client, correcting a case where a target's final/terminal outcome could be reconciled incorrectly.
+
+#### Compatibility
+
+- MSRV raised to Rust 1.88 (from 1.85), to track `ratatui`'s minimum supported Rust version; this applies to the whole workspace, including `irtt-cli`.
+- CI test coverage was expanded to include `musl` and `aarch64` targets, increasing confidence in `irtt-cli` binaries built for those platforms (no code-level behavior change).
+
+## Releasing
+
+Starting with this release, crates are versioned and tagged independently
+rather than in lockstep. Each crate's release is tagged as `<crate>/vX.Y.Z`
+(e.g. `irtt-proto/v0.5.0`), pointing at the commit its version was released
+from. `irtt-proto`, `irtt-client`, `irtt-server`, and `irtt-stats` are
+libraries published to [crates.io](https://crates.io); their tags exist to
+identify the exact source for a given crates.io release and do not produce a
+GitHub Release. The application package (`irtt-cli` through 0.5.0, `irtt-rs`
+from 0.6.0 onward) is the only package with prebuilt binary artifacts: pushing
+an `irtt-rs/vX.Y.Z` tag triggers [cargo-dist](https://opensource.axo.dev/cargo-dist/)
+to build and publish a GitHub Release with platform binaries. The historical
+`irtt-cli/v0.5.0` tag remains as released; it is not rewritten or replaced.

CLAUDE.md

@@ -0,0 +1,4 @@
+# Claude Code
+
+Read and follow `AGENTS.md` before making changes. When working below a subtree
+that contains a more specific `AGENTS.md`, read and follow that file as well.

Cargo.toml

@@ -2,32 +2,32 @@
 members = [
     "crates/irtt-proto",
     "crates/irtt-client",
+    "crates/irtt-server",
     "crates/irtt-stats",
-    "crates/irtt-cli",
+    "crates/irtt-app",
+    "crates/irtt-integration-tests",
 ]
 resolver = "2"
 
 [workspace.package]
 edition = "2021"
 license = "Apache-2.0"
-rust-version = "1.85"
+rust-version = "1.88"
 repository = "https://github.com/Lochnair/irtt-rs"
 homepage = "https://github.com/Lochnair/irtt-rs"
-readme = "README.md"
 
 [workspace.dependencies]
-irtt-proto = { version = "0.4.0", path = "crates/irtt-proto" }
-irtt-client = { version = "0.4.0", path = "crates/irtt-client" }
-irtt-stats = { version = "0.4.0", path = "crates/irtt-stats" }
+irtt-proto = { version = "0.5.0", path = "crates/irtt-proto" }
+irtt-client = { version = "0.6.0", path = "crates/irtt-client" }
+irtt-server = { version = "0.5.2", path = "crates/irtt-server" }
+irtt-stats = { version = "0.5.2", path = "crates/irtt-stats" }
 
 [profile.release]
 opt-level = "z"
 lto = true
 codegen-units = 1
-panic = "abort"
 strip = "symbols"
 
 # The profile that 'dist' will build with
 [profile.dist]
 inherits = "release"
-lto = "thin"

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:1.99-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

@@ -1,264 +1,180 @@
 # irtt-rs
 
-`irtt-rs` is a Rust implementation of an IRTT-compatible client.
+`irtt-rs` is a Rust implementation of an IRTT-compatible client and server:
+finite or continuous UDP latency probing, plus the server side those probes
+run against.
 
-It is not the upstream IRTT project. For the original implementation, protocol background, and broader project documentation, see:
+This is not the upstream IRTT project. For the original implementation,
+protocol background, and broader documentation, see
+[heistp/irtt](https://github.com/heistp/irtt). The installed dispatcher is
+named `irtt-rs` rather than `irtt` to avoid conflicting with or being
+mistaken for it.
 
-<https://github.com/heistp/irtt>
+## Features
 
-## Status
+* Finite and continuous probe sessions
+* Concurrent probing of multiple targets, with staggered or burst pacing
+* Reusable client library with a structured event stream (blocking, Tokio,
+  or managed)
+* Human-readable table output, plus CSV, TSV, and JSON Lines for scripts and
+  monitoring systems, with selectable output columns
+* Optional terminal UI
+* Reusable Tokio-native server library
+* UDP server applet with sensible zero-argument defaults and explicit bind
+  and session-policy options
+* Router-friendly multi-applet binary layout
 
-This repository currently provides:
+## Comparison with upstream IRTT
 
-- `irtt-rs`, the canonical multi-applet binary
-- `irtt-cli`, a stream/text IRTT-compatible client applet
-- `irtt-tui`, an optional terminal UI applet when built with the `tui` feature
-- `irtt-client`, a Rust library for running client sessions and consuming events
-- finite and continuous probe runs
-- table, CSV, TSV, and JSON Lines event-row output formats with selectable columns
-- optional local summary statistics
+`irtt-rs` is an independent, compatible reimplementation, not a successor or
+replacement for upstream IRTT — [heistp/irtt](https://github.com/heistp/irtt)
+remains the original implementation. Interoperability is a project goal; see
+[`docs/INTEROP_COMPARISON.md`](docs/INTEROP_COMPARISON.md) and
+[`docs/protocol/`](docs/protocol/) for the black-box interoperability
+methodology and protocol baseline this project verifies against. Choose
+between them based on the capabilities and deployment model you need.
 
-Server support is not implemented.
-The installed binary is intentionally not named `irtt` to avoid conflicting or
-confusing overlap with upstream IRTT.
+The table below was checked against upstream release
+[v0.9.2](https://github.com/heistp/irtt/releases/tag/v0.9.2) (2026-07-17).
+This project's own interop testing and protocol baseline are currently
+pinned to the prior release, v0.9.1; the wire protocol version number is
+unchanged between the two, but v0.9.2 has not itself been exercised against
+this project's interop harness.
 
-## Install
+| Capability | irtt-rs | upstream IRTT (v0.9.2) |
+| --- | --- | --- |
+| Wire protocol | Protocol version 1, verified against upstream v0.9.1 | Protocol version 1 (unchanged in v0.9.2) |
+| Finite probing | Supported, default 10s | Supported, default 1m |
+| Continuous/indefinite operation | Supported (`--duration 0`); still computes running statistics (see below) | Supported via streaming mode (`-s`, added in v0.9.2); computes no statistics at all in that mode |
+| Statistics in continuous mode | Running count/min/max/mean/variance per target; exact medians unavailable; bounded IPDV tracking | None in streaming mode — raw/event output only, by design, to avoid unbounded memory |
+| Multi-target probing (one invocation) | Supported, with labels and staggered/burst pacing | Not supported — one remote address per invocation |
+| Terminal UI | `irtt-tui`, a live graph/dashboard applet | Not present |
+| Output formats | table, csv, tsv, jsonl, with selectable columns | Text summary, JSON (optionally gzip to file), and a fixed-field raw mode; no CSV/TSV and no column selection |
+| Client/server library API | Separate, independently versioned Rust crates (`irtt-client`, `irtt-server`) | One combined Go package exposing both roles |
+| Server: multiple listeners | `ServerSet` supervises several listeners in one process | `ListenAndServe` also serves multiple requested addresses |
+| Server: wildcard reply-source | Default behavior on Linux/macOS/FreeBSD; refused elsewhere rather than served incorrectly | Opt-in via `--set-src-ip`, with a documented per-packet allocation cost |
+| Server: zero-argument bind | Binds the wildcard address on both families by default, gated by the platform check above | Binds the wildcard address on both families by default; no documented platform gate |
+| Prebuilt release binaries | Published for six target triples | None published; install via `go install` or manual build |
 
-Requires Rust 1.85 or newer.
+Upstream has capabilities this project does not implement: a `report`
+subcommand for replaying saved JSON results, benchmarking and
+timer/clock-diagnostic subcommands, client-side payload fill and
+don't-fragment/wait-strategy/timer-algorithm controls, an operator-configurable
+server-side fill policy (this project's server always honors a session's
+negotiated fill request, with a fixed fallback pattern, but has no equivalent
+to upstream's flags for restricting or overriding it), syslog logging, and
+bundled systemd/OpenRC service files.
 
-From a local checkout:
+This project has capabilities upstream does not implement: multi-target
+probing with labels, the terminal UI, CSV/TSV output with selectable
+columns, a quantified and actively-warned memory-retention model for
+long-running client sessions, and best-effort Linux kernel-timestamp
+preference for its own send/receive endpoint.
+
+## Installation
+
+The build requires Rust 1.88 or newer.
+
+Install the latest release from crates.io:
+
+```sh
+cargo install irtt-rs --locked
+```
+
+This installs the `irtt-rs` dispatcher plus dedicated `irtt-client`,
+`irtt-tui`, and `irtt-server` binaries. Each applet can also be built in
+isolation with `--no-default-features` plus the applet's own feature, for
+example a lightweight client-only install:
+
+```sh
+cargo install irtt-rs --locked --no-default-features --features client
+```
+
+For development, or to install directly from a checkout:
 
 ```sh
 git clone https://github.com/Lochnair/irtt-rs.git
 cd irtt-rs
-cargo install --path crates/irtt-cli
+cargo install --path crates/irtt-app --locked
 ```
 
-The default install provides the normal client-oriented binaries, including
-`irtt-rs` and `irtt-cli`. To install the TUI applet as a separate binary target:
+## Quick start
+
+Probe a server:
 
 ```sh
-cargo install --path crates/irtt-cli --features tui
+irtt-client netperf-eu.bufferbloat.net:2112 --duration 30s --interval 100ms
 ```
 
-Or run it directly without installing:
+Probe continuously until interrupted (`Ctrl-C`):
 
 ```sh
-cargo run -p irtt-cli --bin irtt-cli -- <server>
+irtt-client netperf-eu.bufferbloat.net:2112 --duration 0
 ```
 
-For space-sensitive packaging, such as OpenWrt packages, distributors can ship
-only `irtt-rs` and symlink or hardlink enabled applet names such as `irtt-cli`
-and, when built with the `tui` feature, `irtt-tui` to it. Applet dispatch is
-based on the invoked binary name. Server support is not implemented.
-
-cargo-dist release archives are currently configured with the `full` feature
-set, so target archives bundle the enabled applet binaries: `irtt-rs`,
-`irtt-cli`, and `irtt-tui`. That is separate from space-sensitive package
-layouts, which may still ship one dispatcher binary plus applet-name symlinks
-or hardlinks. cargo-dist is not currently configured to create those links.
-
-## Build verification
-
-Useful local release/package sanity checks:
+Watch the same session live in the terminal UI:
 
 ```sh
-cargo fmt --check
-cargo test -p irtt-cli
-cargo clippy --workspace --all-targets -- -D warnings
-cargo build -p irtt-cli --release
-cargo build -p irtt-cli --no-default-features --release
-cargo build -p irtt-cli --features tui --release
-cargo build -p irtt-cli --all-features --release
+irtt-tui netperf-eu.bufferbloat.net:2112
 ```
 
-The no-default-features build only provides the `irtt-rs` dispatcher binary;
-the default build provides `irtt-rs` and `irtt-cli`; `tui`, `full`, and
-all-features builds also provide `irtt-tui`.
-
-## CLI usage
-
-Basic test:
+Run a server with sensible defaults — no `--bind` needed:
 
 ```sh
-irtt-cli <server>
+irtt-server
 ```
 
-Set duration and interval:
+## Documentation
+
+* [`docs/irtt-client.md`](docs/irtt-client.md) — target syntax, output
+  formats and columns, measurement field definitions, finite/continuous
+  memory behavior, kernel timestamps.
+* [`docs/irtt-tui.md`](docs/irtt-tui.md) — controls, continuous default,
+  retained history.
+* [`docs/irtt-server.md`](docs/irtt-server.md) — bind defaults and
+  overrides, wildcard listener behavior, session policy, HMAC.
+* [`docs/irtt-rs.md`](docs/irtt-rs.md) — the multicall dispatcher, applet
+  binary names, feature-gated builds.
+* [docs.rs](https://docs.rs) for the library crates below.
+* [`docs/protocol/`](docs/protocol/) and
+  [`docs/INTEROP_COMPARISON.md`](docs/INTEROP_COMPARISON.md) for the wire
+  protocol specification and interoperability validation against upstream
+  `irtt`.
+
+Every applet also documents its full option list with `--help`.
+
+## Crates
+
+| Crate | crates.io | What it is |
+| --- | --- | --- |
+| [`irtt-rs`](crates/irtt-app) | [crates.io](https://crates.io/crates/irtt-rs) | Application package: the `irtt-rs`, `irtt-client`, `irtt-tui`, and `irtt-server` binaries |
+| [`irtt-client`](crates/irtt-client) | [crates.io](https://crates.io/crates/irtt-client) | Reusable client/session library ([docs.rs](https://docs.rs/irtt-client)) |
+| [`irtt-server`](crates/irtt-server) | [crates.io](https://crates.io/crates/irtt-server) | Reusable Tokio-native server library ([docs.rs](https://docs.rs/irtt-server)) |
+| [`irtt-stats`](crates/irtt-stats) | [crates.io](https://crates.io/crates/irtt-stats) | Statistics aggregation over `irtt-client` events ([docs.rs](https://docs.rs/irtt-stats)) |
+| [`irtt-proto`](crates/irtt-proto) | [crates.io](https://crates.io/crates/irtt-proto) | Low-level wire protocol encode/decode ([docs.rs](https://docs.rs/irtt-proto)) |
+
+Each library crate has its own crates.io README describing what it's for and
+when to use it instead of `irtt-client`/`irtt-server` directly.
+
+## Binaries and features
+
+| Build | Binaries |
+| --- | --- |
+| `--no-default-features` | `irtt-rs` |
+| `--no-default-features --features client` | `irtt-rs`, `irtt-client` |
+| `--no-default-features --features server` | `irtt-rs`, `irtt-server` |
+| `--no-default-features --features tui` | `irtt-rs`, `irtt-tui` |
+| Default features (or `--all-features`) | `irtt-rs`, `irtt-client`, `irtt-tui`, `irtt-server` |
+
+## Development
 
 ```sh
-irtt-cli <server> --duration 30s --interval 100ms
+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
 ```
 
-Run continuously:
-
-```sh
-irtt-cli <server> --duration 0
-```
-
-Probe multiple targets concurrently:
-
-```sh
-irtt-cli host-a:2112 host-b:2112
-irtt-cli --target ams=ams.example.com:2112 --target sg=sg.example.com:2112
-irtt-cli host-a:2112 host-b:2112 --pacing burst
-```
-
-For positional multi-target runs, the original target string is used as the
-logical target label. Repeated positional strings get a stable numeric suffix.
-For `--target label=host:port`, `label` is used in the `target` output column.
-Labels must be unique. `--pacing staggered|burst` selects managed group pacing
-for multi-target runs; the default is `staggered`.
-
-Use a specific output format or column selection:
-
-```sh
-irtt-cli <server> --format table
-irtt-cli <server> --format jsonl
-irtt-cli <server> --format csv --columns event,seq,remote,effective_rtt_us
-irtt-cli host-a:2112 host-b:2112 --format csv --columns target,seq,effective_rtt_us
-irtt-cli <server> --format tsv --columns effective_rtt_us --header never
-irtt-cli --list-columns
-```
-
-With the optional TUI feature, `irtt-tui` opens a live cumulative dashboard for
-interactive probing. It defaults to continuous probing, equivalent to
-`--duration 0`. Quit with `q` or `Ctrl-C`; the client will drain and close the
-session gracefully.
-
-```sh
-irtt-tui <server>
-irtt-tui <server> --duration 30s
-irtt-tui host-a:2112 host-b:2112 --pacing burst
-irtt-tui --target ams=ams.example.com:2112 --target sg=sg.example.com:2112
-cargo run -p irtt-cli --features tui --bin irtt-tui -- <server>
-```
-
-For available options:
-
-```sh
-irtt-cli --help
-irtt-tui --help   # when built or installed with the tui feature
-```
-
-## Event row output
-
-The stream client separates event row rendering from final summaries. Event rows
-are controlled by `--format`, `--columns`, and `--header`; final summaries remain
-separate table-style text and are printed for table output when the run policy
-allows a summary.
-
-Formats:
-
-- `table`: default, terminal-readable columns with a header
-- `csv`: comma-separated rows, intended for scripts
-- `tsv`: tab-separated rows, useful for one-value streams and shell pipelines
-- `jsonl`: one JSON object per event row, suitable for streaming consumers
-
-Headers are controlled with `--header auto|always|never`. In `auto`, table, CSV,
-and TSV print one header row; JSON Lines never prints a header.
-
-Columns are selected with `-c, --columns <COLUMNS>`, where `COLUMNS` is a
-comma-separated list. Use `--list-columns` to print the available names. Useful
-columns include:
-
-```text
-target, event, seq, remote, token, rtt, rtt_us, raw_rtt_us, effective_rtt_us,
-adjusted_rtt_us, rd, rd_us, sd, sd_us, ipdv, ipdv_us, proc,
-server_processing_us, bytes, send_call_us, timer_error_us, highest_seen,
-server_received, server_window, dscp, ecn, traffic_class, kernel_rx_ns,
-warning_kind, message, event_wall_ns, client_send_wall_ns,
-client_receive_wall_ns
-```
-
-Aliases are accepted for readability: `receive_delay` and `receive_delay_us`
-for `rd` and `rd_us`, `send_delay` and `send_delay_us` for `sd` and `sd_us`,
-`server_processing` for `proc`, `server_received_count` for
-`server_received`, and `server_received_window` for `server_window`.
-
-The default single-target table output favors readability with compact columns:
-`event,seq,rtt,rd,sd,ipdv,proc,message`. It omits `echo_sent` rows. Passing
-`--columns default` is the same as omitting `--columns`, including the default
-table row filtering. Multi-target defaults add `target` as the first column so
-rows can be attributed to a logical target label. Custom table column selections
-include all event rows. CSV, TSV, and JSONL default to all non-target columns
-for single-target export and include `target` by default for multi-target
-export; use `--columns all` explicitly to request every column in any format.
-Missing table values render as `-`; missing CSV and TSV values render as empty
-fields; missing JSONL values render as `null`.
-
-Use JSON Lines for structured event streaming:
-
-Example:
-
-```sh
-irtt-cli <server> --duration 0 --interval 250ms --format jsonl
-```
-
-Each line is one client event object, for example:
-
-```json
-{"event":"echo_reply","seq":4,"remote":"203.0.113.10:2112","token":null,"rtt":"12.1ms","rtt_us":12100,"raw_rtt_us":12400,"effective_rtt_us":12100,"adjusted_rtt_us":12100,"rd":"6.0ms","rd_us":6000,"sd":"6.1ms","sd_us":6100,"ipdv":"300.0µs","ipdv_us":300,"proc":"300.0µs","server_processing_us":300,"bytes":64,"send_call_us":null,"timer_error_us":null,"highest_seen":null,"server_received":5,"server_window":"0x1f","dscp":0,"ecn":0,"traffic_class":0,"kernel_rx_ns":null,"warning_kind":null,"message":null,"event_wall_ns":1760000000012400000,"client_send_wall_ns":1760000000000000000,"client_receive_wall_ns":1760000000012400000}
-```
-
-Consumers should match on the `event` property and read the columns they need.
-RTT, send-call, and timer-error `*_us` fields are reported in microseconds.
-`raw_rtt_us` is the measured client send-to-receive RTT. `effective_rtt_us` and
-`adjusted_rtt_us` are signed and may be negative when server processing exceeds
-the raw RTT or timing correction produces a negative adjusted value. When
-one-way delay fields are present, `sd_us` and `rd_us` are also signed
-microseconds and may be negative due to wall-clock skew.
-
-For consumers that only need effective RTT values in microseconds, use:
-
-```sh
-irtt-cli <server> --format tsv --columns effective_rtt_us --header never
-```
-
-## Library usage
-
-`irtt-client` can be used directly from Rust code.
-
-Example `Cargo.toml` dependency from a local checkout:
-
-```toml
-[dependencies]
-irtt-client = { path = "crates/irtt-client" }
-```
-
-Minimal managed-client example:
-
-```rust
-use std::time::Duration;
-
-use irtt_client::{
-    ClientConfig, ClientEvent, ManagedClient, SubscriberConfig,
-};
-
-fn main() -> Result<(), Box<dyn std::error::Error>> {
-    let config = ClientConfig {
-        server_addr: "netperf-eu.bufferbloat.net:2112".to_owned(),
-        duration: Some(Duration::from_secs(10)),
-        interval: Duration::from_secs(1),
-        ..ClientConfig::default()
-    };
-
-    let (session, events) =
-        ManagedClient::start_with_subscription(config, SubscriberConfig::default())?;
-
-    while let Ok(event) = events.recv() {
-        match event {
-            ClientEvent::EchoReply { seq, rtt, .. } => {
-                println!("seq={seq} rtt_us={}", rtt.effective.as_micros());
-            }
-            ClientEvent::SessionClosed { .. } => break,
-            _ => {}
-        }
-    }
-
-    let outcome = session.join()?;
-    println!("session ended: {:?}", outcome.end_reason);
-
-    Ok(())
-}
-```
+See [`AGENTS.md`](AGENTS.md) for architecture, testing policy, and the
+clean-room provenance boundary this project maintains against upstream
+`irtt`.

crates/irtt-app/Cargo.toml

@@ -0,0 +1,73 @@
+[package]
+name = "irtt-rs"
+version = "0.8.0"
+description = "IRTT-compatible client, TUI, and server applications"
+edition.workspace = true
+license.workspace = true
+rust-version.workspace = true
+repository.workspace = true
+homepage.workspace = true
+readme = "README.md"
+keywords = ["irtt", "networking", "latency", "rtt"]
+categories = ["command-line-utilities", "network-programming"]
+
+[lib]
+name = "irtt_app"
+doc = false
+
+[[bin]]
+name = "irtt-rs"
+path = "src/bin/irtt-rs.rs"
+
+[[bin]]
+name = "irtt-client"
+path = "src/bin/irtt-client.rs"
+required-features = ["client"]
+# This applet shares its name with the irtt-client library crate, whose rustdoc
+# output it would otherwise collide with.
+doc = false
+
+[[bin]]
+name = "irtt-tui"
+path = "src/bin/irtt-tui.rs"
+required-features = ["tui"]
+
+[[bin]]
+name = "irtt-server"
+path = "src/bin/irtt-server.rs"
+required-features = ["server"]
+# This applet shares its name with the irtt-server library crate, whose rustdoc
+# output it would otherwise collide with.
+doc = false
+
+[features]
+default = ["client", "server", "tui"]
+client = ["dep:tokio", "dep:irtt-client", "irtt-client/ancillary", "irtt-client/tokio", "dep:irtt-proto", "dep:irtt-stats"]
+server = ["dep:irtt-server", "dep:tokio"]
+tui =["dep:tokio", "dep:futures-core", "dep:irtt-client", "irtt-client/ancillary", "irtt-client/tokio", "dep:irtt-proto", "dep:irtt-stats", "dep:ratatui", "dep:crossterm", "dep:chrono"]
+
+[dependencies]
+chrono = { version = "0.4.45", default-features = false, features = ["clock"], optional = true }
+clap = { version = "4.6.7", features = ["derive", "env"] }
+crossterm = { version = "0.29.0", features = ["event-stream"], optional = true }
+futures-core = { version = "0.3.34", default-features = false, optional = true }
+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 }
+irtt-stats = { workspace = true, optional = true }
+ratatui = { version = "0.30.2", optional = true }
+tokio = { version = "1.53.2", default-features = false, features = ["rt", "net", "time", "sync", "macros"], optional = true }
+
+[dev-dependencies]
+irtt-server.workspace = true
+tokio = { version = "1.53.2", default-features = false, features = ["rt", "sync"] }
+
+[target.'cfg(unix)'.dev-dependencies]
+nix = { version = "0.31.3", features = ["term", "poll", "signal", "process"] }
+
+[profile.release]
+opt-level = "z"
+lto = true
+codegen-units = 1
+strip = "symbols"

crates/irtt-app/README.md

@@ -0,0 +1,33 @@
+# irtt-rs
+
+The IRTT-compatible client, TUI, and server applications, packaged as Cargo
+package `irtt-rs`.
+
+Installing this crate builds:
+
+- `irtt-rs` — a multicall dispatcher binary that runs the client, TUI, or
+  server applet by subcommand.
+- `irtt-client` — the dedicated client binary (feature `client`).
+- `irtt-tui` — the interactive terminal UI (feature `tui`).
+- `irtt-server` — the dedicated server binary (feature `server`).
+
+All three features are enabled by default, so a plain `cargo install irtt-rs`
+installs everything.
+
+## This is an application, not a library
+
+This package's library target is undocumented (`doc = false`) and exists only
+to share code between its binaries. If you're looking for the client/session
+or server API to embed in your own Rust program, use
+[`irtt-client`](https://crates.io/crates/irtt-client) or
+[`irtt-server`](https://crates.io/crates/irtt-server) instead.
+
+## Usage
+
+See the [project repository](https://github.com/Lochnair/irtt-rs) for
+installation instructions, command-line usage, and configuration.
+
+## Project
+
+Part of [irtt-rs](https://github.com/Lochnair/irtt-rs), an independent Rust
+implementation of an IRTT-compatible protocol stack.

crates/irtt-app/src/applet.rs

@@ -0,0 +1,182 @@
+use std::{ffi::OsString, path::Path};
+
+use clap::Command;
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum RequestedApplet {
+    Client,
+    Tui,
+    Server,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum AppletDispatch {
+    Run {
+        applet: RequestedApplet,
+        argv: Vec<OsString>,
+    },
+    Help(String),
+}
+
+pub fn detect_applet_from_argv0(argv0: &str) -> Option<RequestedApplet> {
+    match applet_basename(argv0) {
+        "irtt-client" => Some(RequestedApplet::Client),
+        "irtt-tui" => Some(RequestedApplet::Tui),
+        "irtt-server" => Some(RequestedApplet::Server),
+        "irtt-rs" => None,
+        _ => None,
+    }
+}
+
+pub fn dispatch_from_argv(argv: Vec<OsString>) -> Result<AppletDispatch, String> {
+    let argv0 = argv
+        .first()
+        .and_then(|arg| arg.to_str())
+        .unwrap_or("irtt-rs");
+
+    if let Some(applet) = detect_applet_from_argv0(argv0) {
+        return Ok(AppletDispatch::Run { applet, argv });
+    }
+
+    let basename = applet_basename(argv0);
+    if basename.starts_with("irtt-") && basename != "irtt-rs" {
+        return Err(format!(
+            "unknown applet name '{basename}'. Known applet names: {}",
+            known_applet_binary_names()
+        ));
+    }
+
+    let Some(command) = argv.get(1).and_then(|arg| arg.to_str()) else {
+        return Err(format!(
+            "choose an applet: {}\n\n{}",
+            applet_command_names(),
+            dispatcher_help()
+        ));
+    };
+
+    match command {
+        "-h" | "--help" => Ok(AppletDispatch::Help(dispatcher_help())),
+        "client" => Ok(AppletDispatch::Run {
+            applet: RequestedApplet::Client,
+            argv: applet_argv("irtt-client", &argv[2..]),
+        }),
+        "tui" => Ok(AppletDispatch::Run {
+            applet: RequestedApplet::Tui,
+            argv: applet_argv("irtt-tui", &argv[2..]),
+        }),
+        "server" => Ok(AppletDispatch::Run {
+            applet: RequestedApplet::Server,
+            argv: applet_argv("irtt-server", &argv[2..]),
+        }),
+        _ => Err(format!(
+            "unknown applet '{command}'. Choose one of: {}\n\n{}",
+            applet_command_names(),
+            dispatcher_help()
+        )),
+    }
+}
+
+pub fn dispatcher_help() -> String {
+    let mut command = Command::new("irtt-rs")
+        .about("IRTT-compatible multi-applet dispatcher")
+        .subcommand(Command::new("client").about(client_applet_about()))
+        .subcommand(Command::new("tui").about(tui_applet_about()))
+        .subcommand(Command::new("server").about(server_applet_about()))
+        .after_help(dispatcher_after_help());
+    command.render_help().to_string()
+}
+
+fn client_applet_about() -> &'static str {
+    if cfg!(feature = "client") {
+        "Run the stream client applet"
+    } else {
+        "Stream client applet is not available in this build"
+    }
+}
+
+fn tui_applet_about() -> &'static str {
+    if cfg!(feature = "tui") {
+        "Run the terminal UI applet"
+    } else {
+        "Terminal UI applet is not available in this build"
+    }
+}
+
+fn server_applet_about() -> &'static str {
+    if cfg!(feature = "server") {
+        "Run the UDP server applet"
+    } else {
+        "UDP server applet is not available in this build"
+    }
+}
+
+fn known_applet_binary_names() -> &'static str {
+    "irtt-rs, irtt-client, irtt-tui, irtt-server"
+}
+
+fn applet_command_names() -> &'static str {
+    "client, tui, or server"
+}
+
+fn dispatcher_after_help() -> String {
+    let mut help = "Recognized applet binary names: irtt-client, irtt-tui, irtt-server".to_owned();
+
+    let mut missing = Vec::new();
+    if !cfg!(feature = "client") {
+        missing.push("irtt-client requires the client feature");
+    }
+    if !cfg!(feature = "server") {
+        missing.push("irtt-server requires the server feature");
+    }
+    if !cfg!(feature = "tui") {
+        missing.push("irtt-tui requires the tui feature");
+    }
+
+    match missing.len() {
+        0 => {}
+        1 => help.push_str(&format!("\nOptional applet: {}", missing[0])),
+        _ => help.push_str(&format!("\nOptional applets: {}", missing.join("; "))),
+    }
+    help
+}
+
+fn applet_basename(argv0: &str) -> &str {
+    let name = Path::new(argv0)
+        .file_name()
+        .and_then(|name| name.to_str())
+        .unwrap_or(argv0);
+    strip_suffix_ignoring_case(name, std::env::consts::EXE_SUFFIX)
+}
+
+/// Removes the platform executable suffix from a file name.
+///
+/// The suffix is part of the file name on Windows and empty everywhere else, so
+/// this is a no-op on Unix. Without it, every applet name — including the
+/// `irtt-rs` dispatcher itself — reaches argv0 detection as `<name>.exe` and is
+/// rejected as an unknown applet. The applet names themselves are still matched
+/// exactly; only this platform artifact is case-insensitive, because it is not
+/// a name the user chose.
+///
+/// The suffix is a parameter so that Windows behavior is assertable from any
+/// host, not only where `EXE_SUFFIX` happens to be non-empty.
+fn strip_suffix_ignoring_case<'a>(name: &'a str, suffix: &str) -> &'a str {
+    if suffix.is_empty() || name.len() <= suffix.len() {
+        return name;
+    }
+    let split = name.len() - suffix.len();
+    let (Some(stem), Some(tail)) = (name.get(..split), name.get(split..)) else {
+        return name;
+    };
+    if tail.eq_ignore_ascii_case(suffix) {
+        stem
+    } else {
+        name
+    }
+}
+
+fn applet_argv(applet_name: &str, args: &[OsString]) -> Vec<OsString> {
+    let mut argv = Vec::with_capacity(args.len() + 1);
+    argv.push(OsString::from(applet_name));
+    argv.extend(args.iter().cloned());
+    argv
+}

crates/irtt-app/src/bin/irtt-client.rs

@@ -1,5 +1,5 @@
 use std::process::ExitCode;
 
 fn main() -> ExitCode {
-    irtt_cli::entry::main()
+    irtt_app::entry::client_main()
 }

crates/irtt-app/src/bin/irtt-rs.rs

@@ -0,0 +1,5 @@
+use std::process::ExitCode;
+
+fn main() -> ExitCode {
+    irtt_app::entry::dispatcher_main()
+}

crates/irtt-app/src/bin/irtt-server.rs

@@ -1,5 +1,5 @@
 use std::process::ExitCode;
 
 fn main() -> ExitCode {
-    irtt_cli::entry::main()
+    irtt_app::entry::server_main()
 }

crates/irtt-app/src/bin/irtt-tui.rs

@@ -1,5 +1,5 @@
 use std::process::ExitCode;
 
 fn main() -> ExitCode {
-    irtt_cli::entry::main()
+    irtt_app::entry::tui_main()
 }

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

@@ -0,0 +1,154 @@
+use std::time::Duration;
+
+use crate::shared::client::{
+    parse_target, parse_test_duration, prepare_managed_run, CommonClientArgs, GroupPacingArg,
+    ManagedRunSetup, TargetArg, TargetSelection, TimestampArg,
+};
+use clap::{Parser, ValueEnum};
+
+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= 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= 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,
+        value_enum,
+        default_value_t = GroupPacingArg::Staggered,
+        long_help = "Managed group pacing for multi-target mode.\n\nstaggered spaces active targets across the probe interval. burst sends one probe to every active target back-to-back once per interval."
+    )]
+    pub pacing: GroupPacingArg,
+
+    #[arg(
+        long,
+        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 when interrupted; --targets-stdin also prints the final retained summary on EOF."
+    )]
+    pub duration: Duration,
+
+    #[command(flatten)]
+    pub common: CommonClientArgs,
+
+    /// Event row output format.
+    #[arg(
+        long,
+        value_enum,
+        default_value_t = OutputFormat::Table,
+        long_help = "Event row output format.\n\nTable is the default interactive format. CSV, TSV, and JSON Lines default to all columns for structured export."
+    )]
+    pub format: OutputFormat,
+
+    /// Comma-separated event row columns, or default/all.
+    #[arg(
+        short = 'c',
+        long,
+        value_name = "COLUMNS",
+        long_help = "Comma-separated event row columns, or default/all.\n\nThe default table columns are compact and hide echo_sent rows. Custom table columns include all event rows. Run --list-columns to see valid names."
+    )]
+    pub columns: Option<String>,
+
+    /// List available event row columns and aliases, then exit.
+    #[arg(
+        long,
+        long_help = "List available event row columns and aliases, then exit.\n\nA server argument is not required when listing columns."
+    )]
+    pub list_columns: bool,
+
+    /// Header policy for table, CSV, and TSV output.
+    #[arg(
+        long,
+        value_enum,
+        default_value_t = HeaderMode::Auto,
+        long_help = "Header policy for table, CSV, and TSV output.\n\nJSON Lines never prints a header."
+    )]
+    pub header: HeaderMode,
+
+    /// Include extra fields in table output and final summaries.
+    #[arg(long)]
+    pub verbose: bool,
+}
+
+impl ClientArgs {
+    /// Validate the selected targets and prepare the managed run.
+    ///
+    /// Targets are only required here. `--list-columns` returns before this is
+    /// called, so listing columns still needs no target.
+    pub async 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,
+            },
+        )
+        .await
+    }
+
+    pub fn is_continuous(&self) -> bool {
+        self.duration == Duration::ZERO
+    }
+
+    pub fn timestamp_mode(&self) -> TimestampArg {
+        self.common.tstamp
+    }
+}
+
+impl std::ops::Deref for ClientArgs {
+    type Target = CommonClientArgs;
+
+    fn deref(&self) -> &Self::Target {
+        &self.common
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, ValueEnum)]
+pub enum OutputFormat {
+    /// Readable terminal table output.
+    Table,
+    /// Comma-separated event rows.
+    Csv,
+    /// Tab-separated event rows.
+    Tsv,
+    /// One JSON object per event row.
+    Jsonl,
+}
+
+impl OutputFormat {
+    pub fn prints_summary(self) -> bool {
+        matches!(self, Self::Table)
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, ValueEnum)]
+pub enum HeaderMode {
+    /// Print headers for table, CSV, and TSV output.
+    Auto,
+    /// Always print headers where the format supports them.
+    Always,
+    /// Never print headers.
+    Never,
+}

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

@@ -1,7 +1,6 @@
 pub mod args;
 pub mod output;
 pub mod run;
-#[cfg(feature = "stats")]
 pub mod summary;
 
 pub use args::{ClientArgs, HeaderMode, OutputFormat};

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

@@ -0,0 +1,762 @@
+use std::{
+    collections::{BTreeMap, BTreeSet, HashSet, VecDeque},
+    io::{self, BufRead, Write},
+    sync::Arc,
+    thread,
+};
+
+use irtt_client::{
+    managed::{
+        ManagedClient, ManagedCommandApplyError, ManagedEndReason, ManagedEvent, ManagedStatus,
+        ManagedTargetEndReason, ManagedTargetOutcome, TargetInstance,
+    },
+    ClientEvent,
+};
+
+use super::{args::ClientArgs, output::OutputConfig};
+
+use crate::shared::client::{
+    expected_probe_count, parse_stdin_target_set,
+    session::{
+        drain_final_events, peer_close_run_error, request_managed_stop_for_peer_close,
+        request_managed_stop_once, should_print_final_summary,
+    },
+    worker::ManagedWorker,
+    ManagedRunSetup, TargetSpec, STDIN_MAX_DESIRED_TARGETS, STDIN_OUTCOME_HISTORY_LIMIT,
+};
+
+use irtt_stats::{EventStatsUpdate, StatsCollector, StatsConfig};
+
+const MIB: u64 = 1024 * 1024;
+
+const GIB: u64 = 1024 * MIB;
+
+const FINITE_STATS_MEMORY_WARNING_BYTES: u64 = 128 * MIB;
+
+const FINITE_STATS_MEMORY_STRONG_WARNING_BYTES: u64 = 512 * MIB;
+
+const FINITE_STATS_MEMORY_VERY_STRONG_WARNING_BYTES: u64 = GIB;
+const MAX_STDIN_RECORD_BYTES: usize = 64 * 1024;
+
+pub async fn run_stream(
+    args: ClientArgs,
+    mut shutdown: tokio::sync::watch::Receiver<bool>,
+) -> Result<(), Box<dyn std::error::Error>> {
+    if args.list_columns {
+        print!("{}", OutputConfig::list_columns());
+        return Ok(());
+    }
+    let setup = tokio::select! {
+        result = args.prepare() => result.map_err(|err| io::Error::new(io::ErrorKind::InvalidInput, err))?,
+        _ = shutdown.wait_for(|requested| *requested) => return Ok(()),
+    };
+    let multi_target = setup.is_multi_target();
+    let output_config = OutputConfig::new(
+        args.format,
+        args.columns.as_deref(),
+        args.header,
+        args.verbose,
+    )
+    .map_err(|err| io::Error::new(io::ErrorKind::InvalidInput, err))?;
+    if setup.stdin_controlled {
+        return run_stdin_stream(setup, output_config, shutdown).await;
+    }
+    let continuous = args.is_continuous();
+    let target_count = setup.target_count();
+
+    if let Some(warning) = finite_stats_memory_warning(&args, target_count) {
+        eprintln!("{warning}");
+    }
+    if *shutdown.borrow() {
+        return Ok(());
+    }
+    let (task, handle) = ManagedClient::task(setup.managed_config(), setup.managed_targets())?;
+    let mut events = handle.subscribe()?;
+    let mut status = handle.subscribe_status();
+    let owner = ManagedWorker::start(task, handle.clone())?;
+    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 = setup
+        .targets
+        .iter()
+        .map(|target| {
+            (
+                target.label.clone(),
+                StatsCollector::new(stats_config(continuous)),
+            )
+        })
+        .collect::<BTreeMap<_, _>>();
+    let mut terminal_targets = HashSet::new();
+    let mut dropped_events = 0_u64;
+    let mut interrupted = false;
+    let mut stop_requested = false;
+    loop {
+        let snapshot = status.borrow_and_update().clone();
+        if *shutdown.borrow() {
+            interrupted = true;
+            if request_managed_stop_once(&mut stop_requested) {
+                drop(handle.stop());
+            }
+        }
+        if request_managed_stop_for_peer_close(
+            continuous,
+            interrupted,
+            snapshot.peer_closed_target_outcomes,
+            &mut stop_requested,
+        ) {
+            drop(handle.stop());
+        }
+        if snapshot.final_outcome.is_some() {
+            break;
+        }
+        tokio::select! {
+            _ = shutdown.changed(), if !interrupted => {}
+            changed = status.changed() => { if changed.is_err() { break; } }
+            event = events.recv() => match event {
+                Ok(event) => process_event(event, &mut stream_output, &mut stats, &mut terminal_targets)?,
+                Err(tokio::sync::broadcast::error::RecvError::Lagged(count)) => {
+                    dropped_events = dropped_events.saturating_add(count);
+                }
+                Err(tokio::sync::broadcast::error::RecvError::Closed) => break,
+            }
+        }
+    }
+    if interrupted {
+        eprintln!("interrupted, closing managed run...");
+    }
+    let outcome = owner.join().await?;
+    drain_final_events(&mut events, &mut dropped_events, |event| {
+        process_event(event, &mut stream_output, &mut stats, &mut terminal_targets)
+    })?;
+    if let Some(warning) = dropped_event_warning(dropped_events) {
+        eprintln!("{warning}");
+    }
+    if outcome.discarded_target_outcomes != 0 {
+        eprintln!(
+            "irtt-rs: warning: {} final target outcomes were discarded",
+            outcome.discarded_target_outcomes
+        );
+    }
+    for target in outcome.recent_target_outcomes.iter() {
+        if terminal_targets.insert(target.target.clone()) {
+            report_target_failure(target);
+        }
+    }
+    interrupted |= *shutdown.borrow();
+    let terminal_error = match &outcome.end_reason {
+        ManagedEndReason::DriverFailed(failure) => {
+            Some(format!("managed driver failed: {failure}"))
+        }
+        _ => peer_close_run_error(continuous, interrupted, outcome.peer_closed_target_outcomes)
+            .or_else(|| {
+                (!interrupted
+                    && outcome.successful_target_outcomes == 0
+                    && outcome.failed_target_outcomes > 0)
+                    .then(|| {
+                        format!(
+                            "no managed target completed successfully ({} failed)",
+                            outcome.failed_target_outcomes
+                        )
+                    })
+            }),
+    };
+    stream_output.print_final_summary = should_print_final_summary(continuous, interrupted);
+    stream_output.show_running_only_summary_note =
+        continuous && interrupted && stream_output.print_final_summary;
+    for target in &setup.targets {
+        let target_stats = stats.get(&target.label).expect(
+            "every prepared target must have a stats collector inserted before the run begins",
+        );
+        if multi_target
+            && stream_output.print_final_summary
+            && stream_output.config.prints_summary()
+        {
+            writeln!(stream_output.out)?;
+            writeln!(stream_output.out, "target: {}", target.label)?;
+        }
+        stream_output.print_summary(target_stats)?;
+    }
+    stream_output.out.flush()?;
+    if let Some(error) = terminal_error {
+        return Err(error.into());
+    }
+    Ok(())
+}
+
+#[derive(Clone)]
+enum StdinUpdate {
+    Targets(Vec<TargetSpec>),
+    Stop(StdinStop),
+}
+
+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,
+    updates: &tokio::sync::watch::Sender<StdinUpdate>,
+) {
+    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) => {
+                        updates.send_replace(StdinUpdate::Targets(targets));
+                    }
+                    Err(error) => {
+                        updates.send_replace(StdinUpdate::Stop(StdinStop::Fatal(format!(
+                            "invalid --targets-stdin line {line}: {error}"
+                        ))));
+                        return;
+                    }
+                }
+            }
+            Ok(None) => {
+                updates.send_replace(StdinUpdate::Stop(StdinStop::Eof));
+                return;
+            }
+            Err(_) => {
+                updates.send_replace(StdinUpdate::Stop(StdinStop::Fatal(format!(
+                    "failed to read --targets-stdin line {}",
+                    line + 1
+                ))));
+                return;
+            }
+        }
+    }
+}
+
+fn spawn_stdin_target_reader(updates: tokio::sync::watch::Sender<StdinUpdate>) -> io::Result<()> {
+    thread::Builder::new()
+        .name("irtt-targets-stdin".to_owned())
+        .spawn(move || {
+            let stdin = io::stdin();
+            read_stdin_target_sets(&mut stdin.lock(), &updates);
+        })
+        .map(|_| ())
+}
+
+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)));
+            let update = collector.process(&event);
+            stream_output.print_event(&event, Some(target.id.as_str()), &update)?;
+        }
+        ManagedEvent::TargetFinished { outcome }
+            if terminal_targets.insert(outcome.target.clone()) =>
+        {
+            report_target_failure(&outcome);
+        }
+        _ => {}
+    }
+    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),
+}
+
+async fn run_stdin_stream(
+    setup: ManagedRunSetup,
+    output_config: OutputConfig,
+    mut shutdown: tokio::sync::watch::Receiver<bool>,
+) -> Result<(), Box<dyn std::error::Error>> {
+    if *shutdown.borrow() {
+        return Ok(());
+    }
+    let (task, handle) = ManagedClient::task(setup.managed_config(), setup.managed_targets())?;
+    let mut events = handle.subscribe()?;
+    let mut status = handle.subscribe_status();
+    let owner = ManagedWorker::start(task, handle.clone())?;
+    let (updates, mut stdin) = tokio::sync::watch::channel(StdinUpdate::Targets(Vec::new()));
+    spawn_stdin_target_reader(updates)?;
+
+    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 stdin_changed = false;
+    let mut preparation = setup.preparation.clone();
+    let mut desired_specs = None;
+    let mut preparing = None;
+    let mut desired = None;
+    let mut pending = None;
+    let mut submitted = Vec::new();
+    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;
+    loop {
+        let snapshot = status.borrow_and_update().clone();
+        if stop.is_none() {
+            if *shutdown.borrow() {
+                stop = Some(StdinStop::Interrupted);
+            } else if stdin_changed || stdin.has_changed().unwrap_or(true) {
+                stdin_changed = false;
+                match stdin.borrow_and_update().clone() {
+                    StdinUpdate::Targets(specs) => {
+                        desired_specs = Some(specs);
+                        desired = None;
+                        retry_after = None;
+                    }
+                    StdinUpdate::Stop(reason) => stop = Some(reason),
+                }
+            }
+            if stop.is_none() && preparing.is_none() {
+                if let Some(specs) = desired_specs.take() {
+                    // Only one preparation runs at a time. Newer records supersede
+                    // its result without piling up uncancellable system DNS jobs.
+                    preparing = Some(Box::pin(
+                        preparation
+                            .clone()
+                            .prepare(specs, Some(STDIN_MAX_DESIRED_TARGETS)),
+                    ));
+                }
+            }
+            if stop.is_none()
+                && pending.is_none()
+                && !retry_after
+                    .as_ref()
+                    .is_some_and(|previous| Arc::ptr_eq(previous, &snapshot))
+            {
+                if let Some(targets) = desired.take() {
+                    submitted = targets;
+                    match handle.update_targets(submitted.clone()) {
+                        Ok(receipt) => {
+                            pending = Some(receipt);
+                            retry_after = Some(snapshot.clone());
+                        }
+                        Err(_) => {
+                            stop = Some(StdinStop::Fatal(
+                                "failed to submit --targets-stdin update".to_owned(),
+                            ))
+                        }
+                    }
+                }
+            }
+            if stop.is_some() {
+                preparing = None;
+                summary_targets = Some(snapshot_stdin_summary_targets(&mut stats, &snapshot));
+                if request_managed_stop_once(&mut stop_requested) {
+                    drop(handle.stop());
+                }
+            }
+        }
+        reconcile_stdin_stats(&mut stats, &snapshot, summary_targets.as_ref());
+        if snapshot.final_outcome.is_some() {
+            break;
+        }
+        tokio::select! {
+            _ = shutdown.changed(), if stop.is_none() => {}
+            _ = stdin.changed(), if stop.is_none() => { stdin_changed = true; }
+            changed = status.changed() => { if changed.is_err() { break; } }
+            result = async { preparing.as_mut().expect("guarded target preparation").await }, if preparing.is_some() && stop.is_none() => {
+                preparing = None;
+                // Let the next loop consume any newer record, including EOF,
+                // before considering this prepared revision for submission.
+                if desired_specs.is_none() && !stdin.has_changed().unwrap_or(true) {
+                    match result {
+                        Ok((targets, next_preparation)) => {
+                            preparation = next_preparation;
+                            desired = Some(targets.into_iter().map(|target| target.managed).collect());
+                            retry_after = None;
+                        }
+                        Err(error) => {
+                            stop = Some(StdinStop::Fatal(format!("invalid --targets-stdin target set: {error}")));
+                            summary_targets = Some(snapshot_stdin_summary_targets(&mut stats, &status.borrow()));
+                            if request_managed_stop_once(&mut stop_requested) { drop(handle.stop()); }
+                        }
+                    }
+                }
+            }
+            result = async { pending.as_mut().expect("guarded pending receipt").await }, if pending.is_some() && stop.is_none() => {
+                pending = None;
+                match result {
+                    Ok(_) => retry_after = None,
+                    Err(ManagedCommandApplyError::LiveGenerationLimitExceeded { .. }) => {
+                        // A newer desired set supersedes this rejected set. Otherwise,
+                        // retry only after the driver's status advances from submission.
+                        if desired.is_none() && desired_specs.is_none() && preparing.is_none() {
+                            desired = Some(std::mem::take(&mut submitted));
+                        } else {
+                            retry_after = None;
+                        }
+                    }
+                    Err(_) => {
+                        stop = Some(StdinStop::Fatal("--targets-stdin update was rejected".to_owned()));
+                        summary_targets = Some(snapshot_stdin_summary_targets(&mut stats, &status.borrow()));
+                        if request_managed_stop_once(&mut stop_requested) { drop(handle.stop()); }
+                    }
+                }
+            }
+            event = events.recv() => match event {
+                Ok(event) => {
+                    process_stdin_event(event, &mut stream_output, &mut stats, &mut terminal_targets)?;
+                    reconcile_stdin_stats(&mut stats, &status.borrow(), summary_targets.as_ref());
+                }
+                Err(tokio::sync::broadcast::error::RecvError::Lagged(count)) => {
+                    dropped_events = dropped_events.saturating_add(count);
+                }
+                Err(tokio::sync::broadcast::error::RecvError::Closed) => break,
+            }
+        }
+    }
+
+    let outcome = owner.join().await?;
+    drain_final_events(&mut events, &mut dropped_events, |event| {
+        process_stdin_event(event, &mut stream_output, &mut stats, &mut terminal_targets)
+    })?;
+    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>,
+    stats: &mut BTreeMap<String, StatsCollector>,
+    terminal_targets: &mut HashSet<TargetInstance>,
+) -> io::Result<()> {
+    match event {
+        ManagedEvent::Client { target, event } => {
+            let collector = stats
+                .entry(target.id.as_str().to_owned())
+                .or_insert_with(|| StatsCollector::new(stats_config(false)));
+            let update = collector.process(&event);
+            stream_output.print_event(&event, Some(target.id.as_str()), &update)?;
+        }
+        ManagedEvent::TargetFinished { outcome } => {
+            terminal_targets.insert(outcome.target.clone());
+            report_target_failure(&outcome);
+        }
+        _ => {}
+    }
+    Ok(())
+}
+
+fn report_target_failure(target: &ManagedTargetOutcome) {
+    for message in target_failure_messages(target) {
+        eprintln!("{message}");
+    }
+}
+
+fn target_failure_messages(target: &ManagedTargetOutcome) -> Vec<String> {
+    let mut messages = Vec::with_capacity(2);
+    if let ManagedTargetEndReason::Failed(failure) = &target.end_reason {
+        messages.push(format!(
+            "irtt-rs: target {} failed ({} {}): {}",
+            target.target.id, failure.phase, failure.kind, failure.message
+        ));
+    }
+    if let Some(failure) = &target.cleanup_failure {
+        messages.push(format!(
+            "irtt-rs: target {} cleanup failed ({} {}): {}",
+            target.target.id, failure.phase, failure.kind, failure.message
+        ));
+    }
+    messages
+}
+fn dropped_event_warning(dropped_events: u64) -> Option<String> {
+    (dropped_events > 0).then(|| format!("irtt-rs: warning: dropped {dropped_events} managed run event{}; output and statistics may be incomplete", if dropped_events == 1 { "" } else { "s" }))
+}
+
+struct StreamOutput<'a, W: Write> {
+    config: OutputConfig,
+    header_printed: bool,
+    print_final_summary: bool,
+    show_running_only_summary_note: bool,
+    out: &'a mut W,
+}
+impl<W: Write> StreamOutput<'_, W> {
+    fn print_event(
+        &mut self,
+        event: &ClientEvent,
+        target: Option<&str>,
+        update: &EventStatsUpdate,
+    ) -> io::Result<()> {
+        self.print_header()?;
+        if let Some(line) = self.config.render_event(event, target, Some(update)) {
+            writeln!(self.out, "{line}")?;
+        }
+        Ok(())
+    }
+    fn print_header(&mut self) -> io::Result<()> {
+        if self.header_printed {
+            return Ok(());
+        }
+        self.header_printed = true;
+        if let Some(header) = self.config.render_header() {
+            writeln!(self.out, "{header}")?;
+        }
+        Ok(())
+    }
+
+    fn print_summary(&mut self, stats: &StatsCollector) -> io::Result<()> {
+        if self.print_final_summary && self.config.prints_summary() {
+            write!(
+                self.out,
+                "{}",
+                crate::cmd::client::summary::format_summary_with_options(
+                    &stats.snapshot(),
+                    crate::cmd::client::summary::SummaryFormatOptions {
+                        verbose: self.config.summary_verbose(),
+                        show_running_only_note: self.show_running_only_summary_note
+                    }
+                )
+            )?;
+        }
+        Ok(())
+    }
+}
+
+fn stats_config(continuous: bool) -> StatsConfig {
+    if continuous {
+        StatsConfig::continuous()
+    } else {
+        StatsConfig::finite()
+    }
+}
+fn finite_stats_memory_warning(args: &ClientArgs, target_count: usize) -> Option<String> {
+    if args.is_continuous() || args.duration.is_zero() {
+        return None;
+    }
+    let target_count = u64::try_from(target_count).unwrap_or(u64::MAX);
+    let total_probe_count =
+        expected_probe_count(args.duration, args.interval).saturating_mul(target_count);
+    // Ask the stats crate what the configuration this run will actually use
+    // retains; the CLI owns the probe count and the thresholds, not the
+    // retention model.
+    let estimated_bytes = stats_config(false).estimated_retained_bytes(total_probe_count);
+    if estimated_bytes < FINITE_STATS_MEMORY_WARNING_BYTES {
+        return None;
+    }
+    let formatted = if estimated_bytes >= GIB {
+        format!("{} GiB", estimated_bytes.saturating_add(GIB / 2) / GIB)
+    } else {
+        format!("{} MiB", estimated_bytes.saturating_add(MIB / 2) / MIB)
+    };
+    let guidance = if estimated_bytes >= FINITE_STATS_MEMORY_VERY_STRONG_WARNING_BYTES {
+        "this may be unsuitable on memory-constrained systems"
+    } else if estimated_bytes >= FINITE_STATS_MEMORY_STRONG_WARNING_BYTES {
+        "consider shortening the run, increasing the interval, or using continuous mode"
+    } else {
+        "use continuous mode for bounded-memory long-running tests"
+    };
+    Some(format!("irtt-rs: warning: finite exact statistics may retain about {formatted} for this run; {guidance}"))
+}

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

@@ -0,0 +1,123 @@
+use std::fmt::Write as _;
+
+use irtt_stats::{Snapshot, TimeStats};
+
+use crate::cmd::format::{
+    format_ns_f64, format_optional_ns_f64 as format_ns_f64_opt,
+    format_optional_ns_i128 as format_ns_i128, format_percent,
+};
+
+pub fn format_summary(summary: &Snapshot) -> String {
+    format_summary_with_options(summary, SummaryFormatOptions::default())
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
+pub struct SummaryFormatOptions {
+    pub verbose: bool,
+    pub show_running_only_note: bool,
+}
+
+pub fn format_summary_with_options(summary: &Snapshot, options: SummaryFormatOptions) -> String {
+    let mut out = String::new();
+    let packets = summary.packets;
+    let loss = summary.loss;
+
+    writeln!(out).unwrap();
+    writeln!(out, "irtt-rs summary").unwrap();
+    if options.show_running_only_note {
+        writeln!(
+            out,
+            "note: medians unavailable in continuous mode; running statistics are bounded-memory"
+        )
+        .unwrap();
+    }
+    writeln!(out).unwrap();
+    writeln!(
+        out,
+        "  {:<18} {:>7} {:>10} {:>10} {:>10} {:>10} {:>10}",
+        "Metric", "Count", "Min", "Mean", "Median", "Max", "Stddev"
+    )
+    .unwrap();
+    writeln!(out, "  {}", "-".repeat(82)).unwrap();
+
+    write_time_row(&mut out, "RTT", &summary.rtt.primary);
+    if options.verbose {
+        write_time_row(&mut out, "raw RTT", &summary.rtt.raw);
+        write_time_row(&mut out, "adjusted RTT", &summary.rtt.adjusted);
+    }
+    write_time_row(&mut out, "IPDV/jitter", &summary.ipdv.round_trip);
+    write_time_row(&mut out, "send IPDV", &summary.ipdv.send);
+    write_time_row(&mut out, "receive IPDV", &summary.ipdv.receive);
+    write_time_row(&mut out, "send delay", &summary.one_way_delay.send_delay);
+    write_time_row(
+        &mut out,
+        "receive delay",
+        &summary.one_way_delay.receive_delay,
+    );
+    write_time_row(
+        &mut out,
+        "server processing",
+        &summary.server_processing.processing,
+    );
+    write_time_row(&mut out, "send call", &summary.send_call);
+    write_time_row(&mut out, "timer error", &summary.timer_error);
+
+    writeln!(out).unwrap();
+    writeln!(
+        out,
+        "packets: sent={} received={} unique={} lost={} loss={}",
+        packets.packets_sent,
+        packets.packets_received,
+        packets.unique_replies,
+        loss.lost_packets,
+        format_percent(loss.packet_loss_percent)
+    )
+    .unwrap();
+    if packets.duplicates != 0 || packets.late_packets != 0 {
+        writeln!(
+            out,
+            "replies: duplicates={} ({}) late={} ({})",
+            packets.duplicates,
+            format_percent(loss.duplicate_percent),
+            packets.late_packets,
+            format_percent(loss.late_packets_percent)
+        )
+        .unwrap();
+    }
+    writeln!(
+        out,
+        "bytes: sent={} received={}",
+        packets.bytes_sent, packets.bytes_received
+    )
+    .unwrap();
+
+    if packets.server_packets_received.is_some() || packets.server_received_window.is_some() {
+        write!(out, "server:").unwrap();
+        if let Some(count) = packets.server_packets_received {
+            write!(out, " received={count}").unwrap();
+        }
+        if let Some(window) = packets.server_received_window {
+            write!(out, " window={window:#x}").unwrap();
+        }
+        writeln!(out).unwrap();
+    }
+
+    out
+}
+
+fn write_time_row(out: &mut String, label: &str, value: &TimeStats) {
+    if value.count == 0 {
+        return;
+    }
+    writeln!(
+        out,
+        "  {label:<18} {:>7} {:>10} {:>10} {:>10} {:>10} {:>10}",
+        value.count,
+        format_ns_i128(value.min_ns),
+        format_ns_f64(value.mean_ns),
+        format_ns_f64_opt(value.median_ns),
+        format_ns_i128(value.max_ns),
+        format_ns_f64(value.stddev_ns())
+    )
+    .unwrap();
+}

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

@@ -0,0 +1,117 @@
+//! Scalar presentation vocabulary shared by the CLI frontends.
+//!
+//! Stream output, the run summary, and the TUI display different metrics in
+//! different layouts, but they render the same *scalars*: nanosecond-scale
+//! durations, percentages, and counts. This module owns those spellings so the
+//! frontends cannot drift apart on units, rounding, or how an absent value is
+//! rendered.
+//!
+//! It is presentation only. Nothing here belongs in `irtt-stats`, and it is
+//! deliberately not a general formatting framework: it holds exactly the
+//! vocabulary more than one frontend needs.
+
+use std::time::Duration;
+
+#[cfg(feature = "client")]
+use irtt_client::SignedDuration;
+
+/// Rendering used wherever a scalar is unavailable.
+pub(crate) const ABSENT: &str = "-";
+
+/// Format a nanosecond scalar.
+///
+/// Unit selection and rounding are one policy for every frontend:
+///
+/// | magnitude | unit | precision |
+/// |-----------|------|-----------|
+/// | `< 1µs`   | `ns` | whole     |
+/// | `< 1ms`   | `µs` | 1 decimal |
+/// | `< 1s`    | `ms` | 1 decimal |
+/// | `>= 1s`   | `s`  | 3 decimals |
+///
+/// Negative values are meaningful (clock offsets, one-way deltas, IPDV), so
+/// the unit is selected from the magnitude and the sign is preserved. Values
+/// that are not finite render as [`ABSENT`].
+pub(crate) fn format_ns_f64(value: f64) -> String {
+    if !value.is_finite() {
+        return ABSENT.to_owned();
+    }
+    let sign = if value.is_sign_negative() { "-" } else { "" };
+    let magnitude = value.abs();
+    if magnitude < 1_000.0 {
+        format!("{sign}{magnitude:.0}ns")
+    } else if magnitude < 1_000_000.0 {
+        format!("{sign}{:.1}µs", magnitude / 1_000.0)
+    } else if magnitude < 1_000_000_000.0 {
+        format!("{sign}{:.1}ms", magnitude / 1_000_000.0)
+    } else {
+        format!("{sign}{:.3}s", magnitude / 1_000_000_000.0)
+    }
+}
+
+/// Format an exact nanosecond scalar with [`format_ns_f64`]'s policy.
+pub(crate) fn format_ns_i128(value: i128) -> String {
+    let sign = if value < 0 { "-" } else { "" };
+    let magnitude = value.saturating_abs() as f64;
+    format!("{sign}{}", format_ns_f64(magnitude))
+}
+
+/// Format an optional nanosecond scalar, rendering `None` as [`ABSENT`].
+pub(crate) fn format_optional_ns_i128(value: Option<i128>) -> String {
+    value.map(format_ns_i128).unwrap_or_else(absent)
+}
+
+/// Format an optional nanosecond scalar, rendering `None` as [`ABSENT`].
+#[cfg(feature = "client")]
+pub(crate) fn format_optional_ns_f64(value: Option<f64>) -> String {
+    value.map(format_ns_f64).unwrap_or_else(absent)
+}
+
+/// Format a duration as a nanosecond scalar.
+pub(crate) fn format_duration(value: Duration) -> String {
+    format_ns_i128(i128::try_from(value.as_nanos()).unwrap_or(i128::MAX))
+}
+
+/// Format a signed duration as a nanosecond scalar, preserving its sign.
+#[cfg(feature = "client")]
+pub(crate) fn format_signed_duration(value: SignedDuration) -> String {
+    format_ns_i128(value.as_nanos())
+}
+
+/// Format a percentage with two decimals; non-finite values render as
+/// [`ABSENT`].
+pub(crate) fn format_percent(value: f64) -> String {
+    if value.is_finite() {
+        format!("{value:.2}%")
+    } else {
+        ABSENT.to_owned()
+    }
+}
+
+/// Format `value` as a percentage of `total`, capped at 100%.
+///
+/// A zero total has no percentage to report and renders as [`ABSENT`].
+#[cfg(feature = "tui")]
+pub(crate) fn format_percent_ratio(value: u64, total: u64) -> String {
+    if total == 0 {
+        ABSENT.to_owned()
+    } else {
+        format_percent((value as f64 / total as f64 * 100.0).min(100.0))
+    }
+}
+
+/// Format a scalar count.
+#[cfg(feature = "tui")]
+pub(crate) fn format_count(value: u64) -> String {
+    value.to_string()
+}
+
+/// Format an optional scalar count, rendering `None` as [`ABSENT`].
+#[cfg(feature = "tui")]
+pub(crate) fn format_optional_count(value: Option<u64>) -> String {
+    value.map(format_count).unwrap_or_else(absent)
+}
+
+fn absent() -> String {
+    ABSENT.to_owned()
+}

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

@@ -1,5 +1,9 @@
 #[cfg(feature = "client")]
 pub mod client;
+#[cfg(any(feature = "client", feature = "tui"))]
+mod format;
+#[cfg(feature = "server")]
+pub mod server;
 #[cfg(feature = "tui")]
 pub mod tui;
 

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

@@ -0,0 +1,259 @@
+use std::{
+    net::{Ipv4Addr, Ipv6Addr, SocketAddr},
+    time::Duration,
+};
+
+use clap::{Parser, ValueEnum};
+use irtt_server::{ServerConfig, TimestampAllowance};
+
+/// The ordinary IRTT port, used to build the zero-argument default binds.
+const DEFAULT_PORT: u16 = 2112;
+
+// Every policy option is optional. An omitted option leaves the corresponding
+// `ServerConfig` default in place rather than restating it here, so library and
+// CLI defaults cannot drift apart.
+#[derive(Debug, Clone, Parser)]
+#[command(
+    name = "irtt-server",
+    about = "Minimal IRTT-compatible UDP server",
+    after_help = "With no --bind, the server listens on the wildcard IRTT port for both address families ([::]:2112 and 0.0.0.0:2112) where the platform supports wildcard reply-source selection.\nRepeat --bind to serve multiple addresses in one process; any explicit --bind replaces the default pair entirely. All listeners use the same policy but keep independent session namespaces."
+)]
+pub struct ServerArgs {
+    /// Local UDP address to bind, as ADDR:PORT. Repeatable.
+    #[arg(
+        long,
+        value_name = "ADDR",
+        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>,
+
+    /// HMAC key; every request must then carry a valid MAC.
+    #[arg(
+        long,
+        value_name = "KEY",
+        value_parser = parse_hmac_key,
+        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>,
+
+    /// Maximum simultaneously live sessions per listener.
+    #[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>,
+
+    /// Maximum echo datagram size a session may negotiate, in bytes.
+    #[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>,
+
+    /// Floor on the negotiated send interval.
+    #[arg(
+        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>,
+
+    /// Echo replies a session may burst before its allowance refills.
+    #[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>,
+
+    /// Release a session after this long without an echo request.
+    #[arg(
+        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>,
+
+    /// Maximum test duration a session may negotiate.
+    #[arg(
+        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>,
+
+    /// How many timestamps this server will provide.
+    #[arg(
+        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,
+        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,
+}
+
+/// The command-line spelling of [`TimestampAllowance`].
+///
+/// A CLI-local enum rather than a `clap` derive on the library type: `irtt-server`
+/// is a reusable crate and has no business depending on an argument parser.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, ValueEnum)]
+pub enum TimestampAllowanceArg {
+    /// Honor every requested timestamp placement.
+    Dual,
+    /// Provide at most one timestamp instant; both becomes midpoint.
+    Single,
+    /// Provide no timestamps.
+    None,
+}
+
+impl From<TimestampAllowanceArg> for TimestampAllowance {
+    fn from(value: TimestampAllowanceArg) -> Self {
+        match value {
+            TimestampAllowanceArg::Dual => Self::Dual,
+            TimestampAllowanceArg::Single => Self::Single,
+            TimestampAllowanceArg::None => Self::None,
+        }
+    }
+}
+
+impl ServerArgs {
+    /// The addresses this invocation binds: the requested `--bind` list, or
+    /// the wildcard IRTT port on both address families if none was given.
+    #[must_use]
+    pub fn resolve_binds(&self) -> Vec<SocketAddr> {
+        if self.bind.is_empty() {
+            vec![
+                SocketAddr::from((Ipv6Addr::UNSPECIFIED, DEFAULT_PORT)),
+                SocketAddr::from((Ipv4Addr::UNSPECIFIED, DEFAULT_PORT)),
+            ]
+        } else {
+            self.bind.clone()
+        }
+    }
+
+    /// Builds the server configuration this invocation asks for.
+    #[must_use]
+    pub fn server_config(&self) -> ServerConfig {
+        let mut config = ServerConfig::default();
+        if let Some(key) = self.hmac.as_ref() {
+            config = config.with_hmac_key(key.as_bytes());
+        }
+        if let Some(value) = self.max_sessions {
+            config = config.with_max_sessions(value);
+        }
+        if let Some(value) = self.max_packet_length {
+            config = config.with_max_packet_length(value);
+        }
+        if let Some(value) = self.min_interval {
+            config = config.with_min_send_interval(value);
+        }
+        if let Some(value) = self.burst {
+            config = config.with_burst_allowance(value);
+        }
+        if let Some(value) = self.idle_timeout {
+            config = config.with_idle_timeout(value);
+        }
+        if let Some(value) = self.max_duration {
+            config = config.with_max_test_duration(value);
+        }
+        if let Some(value) = self.timestamp_allowance {
+            config = config.with_timestamp_allowance(value.into());
+        }
+        // A negative capability flag, so absence is the ordinary enabled state
+        // and the library default is what an unset flag leaves in place.
+        if self.no_dscp {
+            config = config.with_dscp_allowed(false);
+        }
+        config
+    }
+}
+
+/// Rejects an empty HMAC key so a blank shell expansion cannot silently
+/// enable authentication with predictable, empty key material.
+fn parse_hmac_key(input: &str) -> Result<String, String> {
+    if input.is_empty() {
+        return Err("HMAC key must not be empty".to_owned());
+    }
+    Ok(input.to_owned())
+}
+
+/// Parses a duration whose zero is meaningful server policy.
+fn parse_duration_allow_zero(input: &str) -> Result<Duration, String> {
+    if input == "0" {
+        return Ok(Duration::ZERO);
+    }
+    parse_duration_units(input)
+}
+
+/// Parses a duration that must be positive, where absence means "no limit".
+fn parse_positive_duration(input: &str) -> Result<Duration, String> {
+    let value = if input == "0" {
+        Duration::ZERO
+    } else {
+        parse_duration_units(input)?
+    };
+    if value.is_zero() {
+        return Err(
+            "duration must be greater than zero; omit the option for no maximum".to_owned(),
+        );
+    }
+    Ok(value)
+}
+
+fn parse_duration_units(input: &str) -> Result<Duration, String> {
+    let split = input
+        .find(|ch: char| !ch.is_ascii_digit())
+        .ok_or_else(|| "duration must include a unit: ms, s, or m".to_owned())?;
+    let (number, unit) = input.split_at(split);
+    if number.is_empty() {
+        return Err("duration must include a value and a unit: ms, s, or m".to_owned());
+    }
+    let value: u64 = number
+        .parse()
+        .map_err(|_| format!("invalid duration value {input:?}"))?;
+    match unit {
+        "ms" => Ok(Duration::from_millis(value)),
+        "s" => Ok(Duration::from_secs(value)),
+        "m" => value
+            .checked_mul(60)
+            .map(Duration::from_secs)
+            .ok_or_else(|| "duration is too large".to_owned()),
+        _ => Err(format!(
+            "unsupported duration unit {unit:?}; use ms, s, or m"
+        )),
+    }
+}

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

@@ -0,0 +1,5 @@
+pub mod args;
+pub mod run;
+
+pub use args::ServerArgs;
+pub use run::run_server;

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

@@ -0,0 +1,107 @@
+use std::{
+    net::SocketAddr,
+    sync::atomic::{AtomicBool, Ordering},
+    time::Duration,
+};
+
+use irtt_server::{address_family_available, ServerSet, ServerSetError};
+
+use super::args::ServerArgs;
+
+/// How often the shutdown future samples the process-wide signal flag.
+///
+/// The flag a signal handler sets has no async wake mechanism, so the future
+/// polls it on a timer rather than spinning. `ServerSet::run` owns everything
+/// after that future becomes ready, including fanning it out to the listeners.
+const SHUTDOWN_POLL_INTERVAL: Duration = Duration::from_millis(50);
+
+/// Runs the configured listeners until the process is asked to shut down.
+///
+/// The applet owns exactly one current-thread Tokio runtime and one
+/// [`ServerSet`], whatever number of addresses was requested. A single `--bind`
+/// is an ordinary set of one and takes the same path as a set of several: one
+/// construction, one shutdown future, one supervision rule. Listener
+/// concurrency is async I/O concurrency and needs no worker threads.
+pub fn run_server(
+    args: ServerArgs,
+    shutdown_requested: &AtomicBool,
+) -> Result<(), Box<dyn std::error::Error>> {
+    let runtime = tokio::runtime::Builder::new_current_thread()
+        .enable_all()
+        .build()?;
+    runtime.block_on(serve(args, shutdown_requested))
+}
+
+async fn serve(
+    args: ServerArgs,
+    shutdown_requested: &AtomicBool,
+) -> Result<(), Box<dyn std::error::Error>> {
+    let config = args.server_config();
+    let binds = args.resolve_binds();
+    let is_implicit_default = args.bind.is_empty();
+    let set = match ServerSet::bind(binds.clone(), config.clone()).await {
+        Ok(set) => set,
+        Err(ServerSetError::ListenerSetup { addr, source }) => {
+            let family_available = address_family_available(addr);
+            match implicit_default_fallback(is_implicit_default, family_available, &binds, addr) {
+                Some(remaining) => {
+                    eprintln!(
+                        "irtt-server: default listener {addr} unavailable ({source}); \
+                         continuing with the remaining default listener"
+                    );
+                    // `remaining`'s lone survivor is bound exactly as it
+                    // would be alone: the address family that just failed
+                    // has no local support at all, so nothing on that family
+                    // could be competing for the surviving listener's port.
+                    ServerSet::bind(remaining, config).await?
+                }
+                None => return Err(ServerSetError::ListenerSetup { addr, source }.into()),
+            }
+        }
+        Err(err) => return Err(err.into()),
+    };
+    // Only once every listener is up. Announcing one address and then failing
+    // to bind the next would report a service that never started.
+    for addr in set.local_addrs() {
+        eprintln!("irtt-server: listening on {addr}");
+    }
+    set.run(shutdown_signal(shutdown_requested)).await?;
+    Ok(())
+}
+
+/// Whether a listener-setup failure for `failed_addr` should be retried with
+/// a reduced bind set instead of failing the whole invocation, and if so,
+/// what to retry with.
+///
+/// Only the implicit zero-argument default gets this treatment, and only
+/// when `failed_addr`'s own address family has no local support on this host
+/// at all (`family_available` is `false`) — not merely because its specific
+/// port was unavailable for some other reason: already in use, permission
+/// denied, no safe wildcard reply-source path, or anything else
+/// `ServerSet::bind` can fail with. Those are real configuration or
+/// environment problems this invocation should fail on, not silently work
+/// around by dropping a listener the operator asked for. An explicit
+/// `--bind` list keeps the library's ordinary all-or-nothing behavior
+/// regardless.
+fn implicit_default_fallback(
+    is_implicit_default: bool,
+    family_available: bool,
+    original_binds: &[SocketAddr],
+    failed_addr: SocketAddr,
+) -> Option<Vec<SocketAddr>> {
+    if !is_implicit_default || family_available || !original_binds.contains(&failed_addr) {
+        return None;
+    }
+    let remaining: Vec<SocketAddr> = original_binds
+        .iter()
+        .copied()
+        .filter(|&addr| addr != failed_addr)
+        .collect();
+    (!remaining.is_empty()).then_some(remaining)
+}
+
+async fn shutdown_signal(shutdown_requested: &AtomicBool) {
+    while !shutdown_requested.load(Ordering::Relaxed) {
+        tokio::time::sleep(SHUTDOWN_POLL_INTERVAL).await;
+    }
+}

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

@@ -0,0 +1,76 @@
+use std::time::Duration;
+
+use clap::Parser;
+
+use crate::shared::client::{
+    parse_target, parse_test_duration, prepare_managed_run, CommonClientArgs, GroupPacingArg,
+    ManagedRunSetup, TargetArg, TargetSelection,
+};
+
+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= 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= 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>,
+
+    /// Managed group pacing for multi-target mode.
+    #[arg(
+        long,
+        value_enum,
+        default_value_t = GroupPacingArg::Staggered,
+        long_help = "Managed group pacing for multi-target mode.\n\nstaggered spaces active targets across the probe interval. burst sends one probe to every active target back-to-back once per interval."
+    )]
+    pub pacing: GroupPacingArg,
+
+    #[arg(
+        long,
+        default_value = "0",
+        value_parser = parse_test_duration,
+        help = "Test duration; use 0 for continuous mode",
+        long_help = "Test duration; use 0 for continuous mode. The TUI defaults to continuous mode."
+    )]
+    pub duration: Duration,
+
+    #[command(flatten)]
+    pub common: CommonClientArgs,
+}
+
+impl TuiArgs {
+    /// Validate the selected targets and prepare the managed run.
+    ///
+    /// The TUI always requires a target: the parser rejects an empty target
+    /// list, and this rejects a target set that cannot be labelled uniquely.
+    pub async fn prepare(&self) -> Result<ManagedRunSetup, String> {
+        prepare_managed_run(
+            &self.common,
+            self.duration,
+            TargetSelection {
+                targets: &self.targets,
+                pacing: self.pacing,
+                stdin_controlled: false,
+            },
+        )
+        .await
+    }
+
+    pub fn is_continuous(&self) -> bool {
+        self.duration == Duration::ZERO
+    }
+}
+
+impl std::ops::Deref for TuiArgs {
+    type Target = CommonClientArgs;
+
+    fn deref(&self) -> &Self::Target {
+        &self.common
+    }
+}

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

@@ -0,0 +1,278 @@
+use std::{future::poll_fn, io, time::Duration};
+
+use super::ui::{TuiConfig, TuiState, TuiStatus, TuiTerminal};
+use crate::{
+    cmd::tui::args::TuiArgs,
+    shared::client::{
+        session::{drain_final_events, request_managed_stop_once},
+        worker::ManagedWorker,
+    },
+};
+use crossterm::{
+    event::{Event, EventStream, KeyCode, KeyEventKind, KeyModifiers},
+    terminal,
+};
+use futures_core::Stream;
+use irtt_client::{
+    managed::{
+        ManagedClient, ManagedCommandApplyError, ManagedCommandError, ManagedCompletionPolicy,
+        ManagedEndReason, ManagedEvent, ManagedTargetEndReason, ManagedTargetLifecycle,
+    },
+    ClientEvent,
+};
+use ratatui::layout::Rect;
+use tokio::{
+    sync::{broadcast::error::RecvError, watch},
+    time::{sleep, Instant},
+};
+
+const RETRY_DELAY: Duration = Duration::from_millis(1500);
+
+const RENDER_INTERVAL: Duration = Duration::from_millis(100);
+
+pub async fn run_tui(
+    args: TuiArgs,
+    mut shutdown: watch::Receiver<bool>,
+) -> Result<(), Box<dyn std::error::Error>> {
+    let setup = tokio::select! {
+        result = args.prepare() => result.map_err(|err| io::Error::new(io::ErrorKind::InvalidInput, err))?,
+        _ = shutdown.wait_for(|requested| *requested) => return Ok(()),
+    };
+    let continuous = args.is_continuous();
+    if *shutdown.borrow() {
+        return Ok(());
+    }
+    let mut terminal = TuiTerminal::enter()?;
+    let mut state = TuiState::with_target_labels(
+        TuiConfig::from_args(&args, &setup),
+        setup.targets.iter().map(|target| target.label.clone()),
+    );
+    state.set_status(TuiStatus::Opening);
+    terminal.draw(&state)?;
+    let desired_targets = setup.managed_targets();
+    let mut config = setup.managed_config();
+    if continuous {
+        config.completion = ManagedCompletionPolicy::ExplicitStop;
+    }
+    let (task, handle) = match ManagedClient::task(config, desired_targets.clone()) {
+        Ok(value) => value,
+        Err(error) => {
+            state.set_error(error.to_string());
+            terminal.draw(&state)?;
+            return Err(Box::new(error));
+        }
+    };
+    // Both subscriptions exist before the measurement task can be polled.
+    let mut events = handle.subscribe()?;
+    let mut status = handle.subscribe_status();
+    let worker = match ManagedWorker::start(task, handle.clone()) {
+        Ok(worker) => worker,
+        Err(error) => {
+            state.set_run_error(error.to_string());
+            terminal.draw(&state)?;
+            return Err(error.into());
+        }
+    };
+    let completion = worker.join();
+    tokio::pin!(completion);
+    // Input and rendering stay on the frontend executor. EventStream's drop
+    // wakes its reader; no terminal task can outlive the terminal guard.
+    let mut input = EventStream::new();
+    let render = sleep(RENDER_INTERVAL);
+    tokio::pin!(render);
+    let mut interrupted = false;
+    let mut stop_requested = false;
+    let retry = sleep(RETRY_DELAY);
+    tokio::pin!(retry);
+    let mut retry_armed = false;
+    let mut update_receipt = None;
+    let mut dropped_events = 0_u64;
+    let mut events_closed = false;
+    let mut status_closed = false;
+    let outcome = loop {
+        let mut force_render = false;
+        // Default select fairness lets input, status and rendering progress
+        // even when measurement events are continuously ready.
+        tokio::select! {
+            outcome = &mut completion => break outcome,
+            _ = shutdown.changed(), if !interrupted => {
+                interrupted = true;
+                state.set_status(TuiStatus::Interrupted);
+                force_render = true;
+            }
+            changed = status.changed(), if !status_closed => {
+                status_closed = changed.is_err();
+                state.process_managed_status(&status.borrow_and_update());
+                force_render = true;
+            }
+            event = events.recv(), if !events_closed => match event {
+                Ok(event) => force_render = process_tui_event(
+                    event, &mut state,
+                ),
+                Err(RecvError::Lagged(count)) => {
+                    dropped_events = dropped_events.saturating_add(count);
+                    state.mark_dropped_managed_events(dropped_events);
+                    force_render = true;
+                }
+                Err(RecvError::Closed) => events_closed = true,
+            },
+            event = poll_fn(|cx| std::pin::Pin::new(&mut input).poll_next(cx)) => {
+                let event = event.ok_or_else(|| io::Error::new(
+                    io::ErrorKind::UnexpectedEof, "terminal input closed",
+                ))??;
+                match event {
+                    Event::Resize(_, _) => force_render = true,
+                    Event::Key(key) if key.kind != KeyEventKind::Release => {
+                        match key.code {
+                            KeyCode::Char('q') | KeyCode::Char('c')
+                                if key.code == KeyCode::Char('q')
+                                    || key.modifiers.contains(KeyModifiers::CONTROL) => {
+                                interrupted = true;
+                                state.set_status(TuiStatus::Interrupted);
+                                force_render = true;
+                            }
+                            _ => {
+                                let (width, height) = terminal::size()?;
+                                force_render = state.handle_key(
+                                    key.code, Rect::new(0, 0, width, height),
+                                );
+                            }
+                        }
+                    }
+                    _ => {}
+                }
+            }
+            _ = &mut retry, if retry_armed && !interrupted && !*shutdown.borrow() => {
+                state.process_managed_status(&status.borrow());
+                retry_armed = false;
+                update_receipt = match handle.update_targets(desired_targets.clone()) {
+                    Ok(receipt) => Some(receipt),
+                    Err(ManagedCommandError::Stopping | ManagedCommandError::DriverClosed)
+                        if stop_requested || *shutdown.borrow() => None,
+                    Err(error) => return Err(format!("reconnect update failed: {error}").into()),
+                };
+            }
+            result = async { update_receipt.as_mut().unwrap().await },
+                if update_receipt.is_some() => {
+                update_receipt = None;
+                match result {
+                    Ok(ack) => {
+                        state.process_managed_status(&ack.status);
+                        force_render = true;
+                    }
+                    Err(ManagedCommandApplyError::Stopping
+                        | ManagedCommandApplyError::AcknowledgementDisconnected)
+                        if stop_requested || *shutdown.borrow() => {}
+                    Err(error) => return Err(format!("reconnect update failed: {error}").into()),
+                }
+            }
+            _ = &mut render, if !state.paused => force_render = true,
+        }
+        if interrupted && request_managed_stop_once(&mut stop_requested) {
+            drop(handle.stop());
+        }
+        if continuous
+            && !interrupted
+            && !stop_requested
+            && !retry_armed
+            && update_receipt.is_none()
+            && status.borrow().targets.iter().any(|target| {
+                target.desired
+                    && target.outcome.as_ref().is_some_and(|outcome| {
+                        matches!(
+                            outcome.end_reason,
+                            ManagedTargetEndReason::Failed(_)
+                                | ManagedTargetEndReason::PeerClosed
+                                | ManagedTargetEndReason::TestComplete
+                        )
+                    })
+            })
+        {
+            retry.as_mut().reset(Instant::now() + RETRY_DELAY);
+            retry_armed = true;
+        }
+        if force_render {
+            terminal.draw(&state)?;
+            // Schedule from the completed draw, never catch up missed frames.
+            render.as_mut().reset(Instant::now() + RENDER_INTERVAL);
+        }
+    };
+    state.set_status(TuiStatus::Closing);
+    terminal.draw(&state)?;
+    let outcome = match outcome {
+        Ok(outcome) => outcome,
+        Err(error) => {
+            state.set_run_error(error.to_string());
+            terminal.draw(&state)?;
+            return Err(error);
+        }
+    };
+    drain_final_events(&mut events, &mut dropped_events, |event| {
+        process_tui_event(event, &mut state);
+        Ok::<(), std::convert::Infallible>(())
+    })?;
+    state.mark_dropped_managed_events(dropped_events);
+    if !continuous && outcome.discarded_target_outcomes != 0 {
+        state.set_run_error(format!(
+            "{} final target outcomes were discarded",
+            outcome.discarded_target_outcomes
+        ));
+    }
+    for target in outcome.recent_target_outcomes.iter() {
+        state.process_target_outcome(target);
+    }
+    interrupted |= *shutdown.borrow();
+    let error = match &outcome.end_reason {
+        ManagedEndReason::DriverFailed(failure) => {
+            Some(format!("managed driver failed: {failure}"))
+        }
+        _ => (!interrupted
+            && outcome.successful_target_outcomes == 0
+            && outcome.failed_target_outcomes > 0)
+            .then(|| {
+                format!(
+                    "no managed target completed successfully ({} failed)",
+                    outcome.failed_target_outcomes
+                )
+            }),
+    };
+    if let Some(error) = error {
+        state.set_run_error(error.clone());
+        terminal.draw(&state)?;
+        return Err(error.into());
+    }
+    state.set_status(TuiStatus::Complete);
+    terminal.draw(&state)?;
+    Ok(())
+}
+
+fn process_tui_event(event: ManagedEvent, state: &mut TuiState) -> bool {
+    match event {
+        ManagedEvent::Client { target, event } => {
+            let force_render = matches!(
+                event,
+                ClientEvent::SessionStarted(_)
+                    | ClientEvent::NoTestCompleted(_)
+                    | ClientEvent::SessionClosed { .. }
+                    | ClientEvent::Warning { .. }
+            );
+            state.process_target_event(&target, &event);
+            force_render
+        }
+        ManagedEvent::TargetFinished { outcome } => {
+            state.process_target_outcome(&outcome);
+            true
+        }
+        ManagedEvent::TargetStateChanged {
+            target,
+            lifecycle:
+                ManagedTargetLifecycle::Pending
+                | ManagedTargetLifecycle::Connecting
+                | ManagedTargetLifecycle::Opening,
+        } => {
+            state.process_target_opening(&target);
+            true
+        }
+        _ => false,
+    }
+}

crates/irtt-app/src/entry.rs

@@ -0,0 +1,139 @@
+#[cfg(feature = "server")]
+use std::sync::{atomic::AtomicBool, Arc};
+use std::{env, ffi::OsString, process::ExitCode};
+
+use crate::applet::{dispatch_from_argv, AppletDispatch, RequestedApplet};
+#[cfg(feature = "server")]
+use crate::signal::install_signal_handler;
+
+/// Entry point for the `irtt-rs` multicall dispatcher binary.
+///
+/// Chooses an applet by subcommand or by recognized argv0 and may reference
+/// every applet enabled by the active feature set.
+pub fn dispatcher_main() -> ExitCode {
+    run_with_exit_code("irtt-rs", run_dispatcher_from_env)
+}
+
+/// Entry point for the dedicated `irtt-client` binary.
+///
+/// Runs the stream client directly; it never consults argv0 or the applet
+/// dispatcher, so a renamed or copied executable still runs the client.
+#[cfg(feature = "client")]
+pub fn client_main() -> ExitCode {
+    run_with_exit_code("irtt-client", || {
+        run_client_applet(env::args_os().collect())
+    })
+}
+
+/// Entry point for the dedicated `irtt-tui` binary.
+///
+/// Runs the terminal UI directly; it never consults argv0 or the applet
+/// dispatcher, so a renamed or copied executable still runs the TUI.
+#[cfg(feature = "tui")]
+pub fn tui_main() -> ExitCode {
+    run_with_exit_code("irtt-tui", || run_tui_applet(env::args_os().collect()))
+}
+
+/// Entry point for the dedicated `irtt-server` binary.
+///
+/// Runs the server directly; it never consults argv0 or the applet
+/// dispatcher, so a renamed or copied executable still runs the server.
+#[cfg(feature = "server")]
+pub fn server_main() -> ExitCode {
+    run_with_exit_code("irtt-server", || {
+        run_server_applet(env::args_os().collect())
+    })
+}
+
+fn run_with_exit_code(
+    program: &str,
+    f: impl FnOnce() -> Result<(), Box<dyn std::error::Error>>,
+) -> ExitCode {
+    match f() {
+        Ok(()) => ExitCode::SUCCESS,
+        Err(err) => {
+            eprintln!("{program}: {err}");
+            ExitCode::FAILURE
+        }
+    }
+}
+
+fn run_dispatcher_from_env() -> Result<(), Box<dyn std::error::Error>> {
+    let argv: Vec<OsString> = env::args_os().collect();
+    let (requested, argv) = match dispatch_from_argv(argv)? {
+        AppletDispatch::Run { applet, argv } => (applet, argv),
+        AppletDispatch::Help(help) => {
+            print!("{help}");
+            return Ok(());
+        }
+    };
+
+    match requested {
+        RequestedApplet::Client => run_client_applet(argv),
+        RequestedApplet::Tui => run_tui_applet(argv),
+        RequestedApplet::Server => run_server_applet(argv),
+    }
+}
+
+/// Installs the shutdown signal handler for synchronous applets and hands the
+/// resulting flag to `f`.
+#[cfg(feature = "server")]
+fn with_shutdown_flag(
+    f: impl FnOnce(&AtomicBool) -> Result<(), Box<dyn std::error::Error>>,
+) -> Result<(), Box<dyn std::error::Error>> {
+    let shutdown_requested = Arc::new(AtomicBool::new(false));
+    install_signal_handler(Arc::clone(&shutdown_requested))
+        .map_err(|err| format!("failed to install signal handler: {err}"))?;
+    f(shutdown_requested.as_ref())
+}
+
+#[cfg(feature = "client")]
+fn run_client_applet(argv: Vec<OsString>) -> Result<(), Box<dyn std::error::Error>> {
+    use clap::Parser;
+
+    let shutdown = crate::signal::install_async_signal_handler()
+        .map_err(|err| format!("failed to install signal handler: {err}"))?;
+    let args = crate::cmd::client::ClientArgs::parse_from(argv);
+    tokio::runtime::Builder::new_current_thread()
+        .enable_all()
+        .build()?
+        .block_on(crate::cmd::client::run_stream(args, shutdown))
+}
+
+#[cfg(not(feature = "client"))]
+fn run_client_applet(_argv: Vec<OsString>) -> Result<(), Box<dyn std::error::Error>> {
+    Err("client applet is not available; rebuild with the client feature".into())
+}
+
+#[cfg(feature = "server")]
+fn run_server_applet(argv: Vec<OsString>) -> Result<(), Box<dyn std::error::Error>> {
+    use clap::Parser;
+
+    with_shutdown_flag(|shutdown_requested| {
+        let args = crate::cmd::server::ServerArgs::parse_from(argv);
+        crate::cmd::server::run_server(args, shutdown_requested)
+    })
+}
+
+#[cfg(not(feature = "server"))]
+fn run_server_applet(_argv: Vec<OsString>) -> Result<(), Box<dyn std::error::Error>> {
+    Err("server applet is not available; rebuild with the server feature".into())
+}
+
+#[cfg(feature = "tui")]
+fn run_tui_applet(argv: Vec<OsString>) -> Result<(), Box<dyn std::error::Error>> {
+    use clap::Parser;
+
+    let shutdown = crate::signal::install_async_signal_handler()
+        .map_err(|err| format!("failed to install signal handler: {err}"))?;
+    let args = crate::cmd::tui::TuiArgs::parse_from(argv);
+    tokio::runtime::Builder::new_current_thread()
+        .enable_all()
+        .build()?
+        .block_on(crate::cmd::tui::run_tui(args, shutdown))
+}
+
+#[cfg(not(feature = "tui"))]
+fn run_tui_applet(_argv: Vec<OsString>) -> Result<(), Box<dyn std::error::Error>> {
+    Err("TUI applet is not available; rebuild with the tui feature".into())
+}

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

@@ -1,11 +1,23 @@
-use std::time::Duration;
+use std::{fmt, time::Duration};
 
 use clap::ValueEnum;
 use irtt_client::{MAX_DSCP_CODEPOINT, MAX_SERVER_FILL_BYTES, MAX_TTL, MAX_UDP_PAYLOAD_LENGTH};
 use irtt_proto::{Clock, ReceivedStats, StampAt};
 
-#[derive(Debug, Clone, clap::Args)]
+#[derive(Clone, clap::Args)]
 pub struct CommonClientArgs {
+    /// Use IPv4 only.
+    #[arg(short = '4', long, conflicts_with_all = ["ipv6", "dual_stack"])]
+    pub ipv4: bool,
+
+    /// Use IPv6 only.
+    #[arg(short = '6', long, conflicts_with_all = ["ipv4", "dual_stack"])]
+    pub ipv6: bool,
+
+    /// Probe available IPv4 and IPv6 paths separately for each hostname.
+    #[arg(long, conflicts_with_all = ["ipv4", "ipv6"], long_help = "Probe available IPv4 and IPv6 paths separately for each hostname. Labels gain /v4 or /v6; IP literals remain single targets. Families are discovered when a target is added; reconnects resolve the original hostname again within the chosen family.")]
+    pub dual_stack: bool,
+
     /// Probe interval.
     #[arg(long, default_value = "1s", value_parser = parse_duration)]
     pub interval: Duration,
@@ -15,7 +27,7 @@ pub struct CommonClientArgs {
     pub length: u32,
 
     /// HMAC key.
-    #[arg(long)]
+    #[arg(long, value_parser = parse_hmac_key)]
     pub hmac: Option<String>,
 
     /// Clock mode to request.
@@ -63,6 +75,26 @@ pub struct CommonClientArgs {
     pub loose: bool,
 }
 
+impl fmt::Debug for CommonClientArgs {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("CommonClientArgs")
+            .field("ipv4", &self.ipv4)
+            .field("ipv6", &self.ipv6)
+            .field("dual_stack", &self.dual_stack)
+            .field("interval", &self.interval)
+            .field("length", &self.length)
+            .field("hmac", &self.hmac.as_ref().map(|_| "[REDACTED]"))
+            .field("clock", &self.clock)
+            .field("tstamp", &self.tstamp)
+            .field("stats", &self.stats)
+            .field("server_fill", &self.server_fill)
+            .field("dscp", &self.dscp)
+            .field("ttl", &self.ttl)
+            .field("loose", &self.loose)
+            .finish()
+    }
+}
+
 #[derive(Debug, Clone, Copy, PartialEq, Eq, ValueEnum)]
 pub enum ClockArg {
     Wall,
@@ -189,6 +221,13 @@ pub fn parse_length(input: &str) -> Result<u32, String> {
     Ok(length)
 }
 
+pub fn parse_hmac_key(input: &str) -> Result<String, String> {
+    if input.is_empty() {
+        return Err("HMAC key must not be empty".to_owned());
+    }
+    Ok(input.to_owned())
+}
+
 pub fn parse_server_fill(input: &str) -> Result<String, String> {
     if input.is_empty() {
         return Err("server fill must not be empty".to_owned());

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

@@ -0,0 +1,72 @@
+use std::time::Duration;
+
+use irtt_client::{
+    AddressFamily, Authentication, ClientConfig, HmacKey, NegotiationPolicy, OpenPolicy,
+    SessionRequest, SocketConfig,
+};
+
+use super::args::CommonClientArgs;
+
+impl CommonClientArgs {
+    pub fn address_family(&self) -> AddressFamily {
+        if self.ipv4 {
+            AddressFamily::Ipv4
+        } else if self.ipv6 {
+            AddressFamily::Ipv6
+        } else {
+            AddressFamily::Any
+        }
+    }
+
+    /// Build the shared client configuration template for a managed run.
+    ///
+    /// The config is endpoint-independent; managed targets own their addresses.
+    pub fn to_client_config(&self, duration: Duration) -> ClientConfig {
+        ClientConfig {
+            address_family: self.address_family(),
+            open: OpenPolicy {
+                negotiation: if self.loose {
+                    NegotiationPolicy::Loose
+                } else {
+                    NegotiationPolicy::Strict
+                },
+                ..Default::default()
+            },
+            request: SessionRequest {
+                duration: (!duration.is_zero()).then_some(duration),
+                interval: self.interval,
+                length: self.length,
+                received_stats: self.stats.into(),
+                stamp_at: self.tstamp.into(),
+                clock: self.clock.into(),
+                dscp: self.dscp,
+                server_fill: self.server_fill.clone(),
+                ..Default::default()
+            },
+            auth: self
+                .hmac
+                .as_ref()
+                .map_or(Authentication::Unauthenticated, |key| {
+                    Authentication::Hmac(HmacKey::new(key.as_bytes()))
+                }),
+            socket: SocketConfig {
+                ttl: self.ttl,
+                ..SocketConfig::default()
+            },
+            ..ClientConfig::default()
+        }
+    }
+}
+
+pub fn expected_probe_count(duration: Duration, interval: Duration) -> u64 {
+    let interval_nanos = interval.as_nanos();
+    if interval_nanos == 0 {
+        return u64::MAX;
+    }
+
+    let expected = duration
+        .as_nanos()
+        .saturating_add(interval_nanos.saturating_sub(1))
+        / interval_nanos;
+    expected.min(u128::from(u64::MAX)) as u64
+}

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

@@ -0,0 +1,20 @@
+pub mod args;
+pub mod config;
+pub mod prepare;
+pub mod session;
+pub mod targets;
+pub(crate) mod worker;
+
+pub use args::{
+    parse_dscp, parse_duration, parse_length, parse_server_fill, parse_test_duration, parse_ttl,
+    ClockArg, CommonClientArgs, ReceivedStatsArg, TimestampArg,
+};
+pub use config::expected_probe_count;
+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 targets::{
+    parse_stdin_target_set, parse_target, target_specs, GroupPacingArg, PreparedTarget, TargetArg,
+    TargetPreparation, TargetSpec,
+};

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

@@ -0,0 +1,133 @@
+//! One preparation step from parsed arguments to a runnable managed setup.
+//!
+//! Both client applets accept the same target and pacing arguments and then
+//! have to turn them into the same three things: a validated target set, one
+//! shared [`ClientConfig`] template, and a [`ManagedPacing`]. Doing that
+//! separately in each applet is how the CLI ended up deriving its client
+//! configuration from an arbitrary "primary" target whose address the managed
+//! driver immediately replaced per target.
+
+use std::time::Duration;
+
+use irtt_client::{
+    managed::{ManagedClientConfig, ManagedCompletionPolicy, ManagedPacing},
+    ClientConfig,
+};
+
+use super::{
+    args::CommonClientArgs,
+    targets::{target_specs, GroupPacingArg, TargetArg, TargetPreparation},
+    PreparedTarget,
+};
+
+/// 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.
+///
+/// Duration is deliberately absent: the applets disagree about what a duration
+/// means and what its default is, so each keeps its own.
+#[derive(Debug, Clone, Copy)]
+pub struct TargetSelection<'a> {
+    pub targets: &'a [TargetArg],
+    pub pacing: GroupPacingArg,
+    pub stdin_controlled: bool,
+}
+
+/// Everything a managed run needs, prepared and validated together.
+#[derive(Debug, Clone)]
+pub struct ManagedRunSetup {
+    /// Validated targets, in the order the user gave them.
+    pub targets: Vec<PreparedTarget>,
+    /// Shared client configuration template.
+    ///
+    /// The managed driver supplies each target's address and authentication
+    /// from its [`ManagedTargetConfig`](irtt_client::managed::ManagedTargetConfig),
+    /// so this template carries no target of its own.
+    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,
+    /// Preparation policy and family selections for later stdin declarations.
+    pub preparation: TargetPreparation,
+}
+
+impl ManagedRunSetup {
+    /// Number of validated targets.
+    pub fn target_count(&self) -> usize {
+        self.targets.len()
+    }
+
+    /// Whether this run drives more than one target.
+    pub fn is_multi_target(&self) -> bool {
+        self.targets.len() > 1
+    }
+
+    /// Managed target configurations, in argument order.
+    pub fn managed_targets(&self) -> Vec<irtt_client::managed::ManagedTargetConfig> {
+        self.targets
+            .iter()
+            .map(|target| target.managed.clone())
+            .collect()
+    }
+
+    /// Managed driver configuration for this run.
+    pub fn managed_config(&self) -> ManagedClientConfig {
+        let target_count = self.target_count();
+        let mut config = ManagedClientConfig {
+            client: self.client.clone(),
+            pacing: self.pacing,
+            completion: ManagedCompletionPolicy::FinishWhenQuiescent,
+            event_capacity: MANAGED_EVENT_CAPACITY,
+            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
+    }
+}
+
+/// Validate the selected targets and build the shared run setup.
+///
+/// Targets are validated before any configuration is built, so a bad target set
+/// fails before the caller can act on a half-prepared run.
+pub async fn prepare_managed_run(
+    common: &CommonClientArgs,
+    duration: Duration,
+    selection: TargetSelection<'_>,
+) -> Result<ManagedRunSetup, String> {
+    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, preparation) = TargetPreparation::new(common.address_family(), common.dual_stack)
+        .prepare(
+            specs,
+            selection
+                .stdin_controlled
+                .then_some(STDIN_MAX_DESIRED_TARGETS),
+        )
+        .await?;
+    Ok(ManagedRunSetup {
+        targets,
+        client: common.to_client_config(duration),
+        pacing: selection.pacing.into(),
+        stdin_controlled: selection.stdin_controlled,
+        preparation,
+    })
+}

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

@@ -0,0 +1,61 @@
+use irtt_client::managed::{ManagedEvent, ManagedEventSubscription, ManagedEventTryRecvError};
+
+pub(crate) fn drain_final_events<E>(
+    events: &mut ManagedEventSubscription,
+    dropped_events: &mut u64,
+    mut process: impl FnMut(ManagedEvent) -> Result<(), E>,
+) -> Result<(), E> {
+    loop {
+        match events.try_recv() {
+            Ok(event) => process(event)?,
+            Err(ManagedEventTryRecvError::Empty | ManagedEventTryRecvError::Closed) => break,
+            Err(ManagedEventTryRecvError::Lagged(count)) => {
+                *dropped_events = dropped_events.saturating_add(count);
+            }
+        }
+    }
+    Ok(())
+}
+
+pub fn should_print_final_summary(continuous: bool, interrupted: bool) -> bool {
+    !continuous || interrupted
+}
+
+pub fn peer_close_run_error(
+    continuous: bool,
+    interrupted: bool,
+    peer_closed_target_outcomes: u64,
+) -> Option<String> {
+    if !continuous || interrupted || peer_closed_target_outcomes == 0 {
+        return None;
+    }
+
+    let sessions = if peer_closed_target_outcomes == 1 {
+        "target session"
+    } else {
+        "target sessions"
+    };
+    Some(format!(
+        "continuous run ended because of peer closure ({peer_closed_target_outcomes} {sessions})"
+    ))
+}
+
+pub fn request_managed_stop_for_peer_close(
+    continuous: bool,
+    interrupted: bool,
+    peer_closed_target_outcomes: u64,
+    stop_requested: &mut bool,
+) -> bool {
+    if !continuous || interrupted || peer_closed_target_outcomes == 0 {
+        return false;
+    }
+    request_managed_stop_once(stop_requested)
+}
+
+pub fn request_managed_stop_once(stop_requested: &mut bool) -> bool {
+    if *stop_requested {
+        return false;
+    }
+    *stop_requested = true;
+    true
+}

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

@@ -0,0 +1,426 @@
+use std::{
+    collections::{HashMap, HashSet},
+    fmt, io,
+    net::{IpAddr, SocketAddr},
+};
+
+use clap::ValueEnum;
+use irtt_client::{
+    managed::{ManagedPacing, ManagedTargetConfig, TargetAuth, TargetId},
+    AddressFamily, Authentication, HmacKey,
+};
+
+/// 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 {
+    input: String,
+}
+
+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 struct TargetSpec {
+    pub label: String,
+    pub addr: String,
+    pub auth: TargetAuth,
+}
+
+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("address_family", &self.managed.address_family)
+            .field("auth", &self.managed.auth)
+            .finish()
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, ValueEnum)]
+pub enum GroupPacingArg {
+    Staggered,
+    Burst,
+}
+
+impl From<GroupPacingArg> for ManagedPacing {
+    fn from(value: GroupPacingArg) -> Self {
+        match value {
+            GroupPacingArg::Staggered => Self::Staggered,
+            GroupPacingArg::Burst => Self::Burst,
+        }
+    }
+}
+
+#[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)
+    }
+}
+
+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::Override(Authentication::Unauthenticated)
+            } else {
+                TargetAuth::Override(Authentication::Hmac(HmacKey::new(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::<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(addr.clone()).or_default();
+                *count += 1;
+                if *count == 1 {
+                    addr.clone()
+                } else {
+                    format!("{}#{}", addr, *count)
+                }
+            }
+        };
+        specs.push(TargetSpec { label, addr, auth });
+    }
+
+    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("duplicate target label".to_owned());
+        }
+    }
+
+    Ok(specs)
+}
+
+pub fn target_specs(targets: &[TargetArg]) -> Result<Vec<TargetSpec>, String> {
+    target_specs_with_empty(targets, false)
+}
+
+/// Family selections for the current desired declarations, never resolved IPs.
+/// Unchanged stdin declarations retain their selections; removed declarations
+/// are forgotten, so adding them again performs fresh discovery.
+#[derive(Debug, Clone)]
+pub struct TargetPreparation {
+    family: AddressFamily,
+    dual_stack: bool,
+    discovered: HashMap<String, (String, [bool; 2])>,
+}
+
+impl TargetPreparation {
+    pub fn new(family: AddressFamily, dual_stack: bool) -> Self {
+        Self {
+            family,
+            dual_stack,
+            discovered: HashMap::new(),
+        }
+    }
+
+    pub async fn prepare(
+        mut self,
+        specs: Vec<TargetSpec>,
+        maximum_targets: Option<usize>,
+    ) -> Result<(Vec<PreparedTarget>, Self), String> {
+        let mut targets = Vec::with_capacity(specs.len());
+        let mut discovered = HashMap::new();
+        let mut labels = HashSet::new();
+        for (index, spec) in specs.into_iter().enumerate() {
+            let families = if let Some(ip) = literal_ip(&spec.addr) {
+                match (self.family, ip) {
+                    (AddressFamily::Ipv4, IpAddr::V6(_)) => {
+                        return Err(format!(
+                            "target {}: IPv6 literal conflicts with --ipv4",
+                            index + 1
+                        ))
+                    }
+                    (AddressFamily::Ipv6, IpAddr::V4(_)) => {
+                        return Err(format!(
+                            "target {}: IPv4 literal conflicts with --ipv6",
+                            index + 1
+                        ))
+                    }
+                    _ => None,
+                }
+            } else if self.dual_stack {
+                let families = match self.discovered.get(&spec.label) {
+                    Some((addr, families)) if *addr == spec.addr => *families,
+                    _ => {
+                        let endpoint = discovery_endpoint(&spec.addr)
+                            .map_err(|error| format!("target {}: {error}", index + 1))?;
+                        discovery_families(tokio::net::lookup_host(endpoint).await)
+                            .map_err(|error| format!("target {}: {error}", index + 1))?
+                    }
+                };
+                discovered.insert(spec.label.clone(), (spec.addr.clone(), families));
+                Some(families)
+            } else {
+                None
+            };
+            for target in expand_target(spec, families) {
+                if !labels.insert(target.label.clone()) {
+                    return Err("duplicate target label after address-family expansion".to_owned());
+                }
+                targets.push(target);
+            }
+            if let Some(maximum) = maximum_targets.filter(|maximum| targets.len() > *maximum) {
+                return Err(format!(
+                    "target set exceeds the {maximum}-target limit after address-family expansion"
+                ));
+            }
+        }
+        self.discovered = discovered;
+        Ok((targets, self))
+    }
+}
+
+fn literal_ip(endpoint: &str) -> Option<IpAddr> {
+    endpoint
+        .parse::<SocketAddr>()
+        .map(|addr| addr.ip())
+        .ok()
+        .or_else(|| endpoint.parse().ok())
+        .or_else(|| {
+            if endpoint.starts_with('[') && endpoint.ends_with(']') {
+                format!("{endpoint}:2112")
+                    .parse::<SocketAddr>()
+                    .ok()
+                    .map(|addr| addr.ip())
+            } else {
+                None
+            }
+        })
+}
+
+fn discovery_endpoint(endpoint: &str) -> Result<(&str, u16), String> {
+    match endpoint.rsplit_once(':') {
+        Some((host, port)) => {
+            let port = port.parse().map_err(|_| "invalid server port".to_owned())?;
+            if host.is_empty() || host.contains(':') || host.starts_with('[') {
+                return Err("invalid server endpoint".to_owned());
+            }
+            Ok((host, port))
+        }
+        None => Ok((endpoint, 2112)),
+    }
+}
+
+fn discovery_families(
+    result: io::Result<impl Iterator<Item = SocketAddr>>,
+) -> Result<[bool; 2], String> {
+    let mut families = [false; 2];
+    for addr in result.map_err(|_| "DNS lookup failed".to_owned())? {
+        families[usize::from(addr.is_ipv6())] = true;
+    }
+    if families == [false; 2] {
+        return Err("DNS lookup returned no usable addresses".to_owned());
+    }
+    Ok(families)
+}
+
+fn expand_target(spec: TargetSpec, families: Option<[bool; 2]>) -> Vec<PreparedTarget> {
+    let selections = match families {
+        None => vec![(spec.label, None)],
+        Some(families) => [("v4", AddressFamily::Ipv4), ("v6", AddressFamily::Ipv6)]
+            .into_iter()
+            .zip(families)
+            .filter(|(_, exists)| *exists)
+            .map(|((suffix, family), _)| (format!("{}/{suffix}", spec.label), Some(family)))
+            .collect(),
+    };
+    selections
+        .into_iter()
+        .map(|(label, family)| {
+            let mut managed =
+                ManagedTargetConfig::new(TargetId::from(label.clone()), spec.addr.clone());
+            managed.address_family = family;
+            managed.auth = spec.auth.clone();
+            PreparedTarget { label, managed }
+        })
+        .collect()
+}
+
+/// 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<TargetSpec>, String> {
+    if record == "[]" {
+        return Ok(Vec::new());
+    }
+    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<_>>();
+    target_specs_with_empty(&args, true)
+}

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

@@ -0,0 +1,67 @@
+use std::{io, thread, time::Duration};
+
+use irtt_client::managed::{ManagedClientHandle, ManagedClientTask, ManagedOutcome};
+use tokio::sync::oneshot;
+
+/// Keeps measurement scheduling separate from frontend output and statistics.
+/// Drop also stops and joins on frontend errors or cancellation.
+pub(crate) struct ManagedWorker {
+    handle: ManagedClientHandle,
+    thread: Option<thread::JoinHandle<()>>,
+    completion: oneshot::Receiver<io::Result<ManagedOutcome>>,
+}
+
+impl ManagedWorker {
+    pub(crate) fn start(task: ManagedClientTask, handle: ManagedClientHandle) -> io::Result<Self> {
+        let (completed, completion) = oneshot::channel();
+        let thread = thread::Builder::new()
+            .name("irtt-managed".to_owned())
+            .spawn(move || {
+                // Construct and destroy the runtime on its owning thread, including
+                // startup failures; never drop a runtime inside the frontend executor.
+                let outcome = (|| {
+                    let runtime = tokio::runtime::Builder::new_current_thread()
+                        .enable_all()
+                        .build()?;
+                    let outcome = std::panic::catch_unwind(std::panic::AssertUnwindSafe(|| {
+                        runtime.block_on(task)
+                    }));
+                    runtime.shutdown_timeout(Duration::from_millis(100));
+                    match outcome {
+                        Ok(outcome) => Ok(outcome),
+                        Err(panic) => std::panic::resume_unwind(panic),
+                    }
+                })();
+                let _ = completed.send(outcome);
+            })?;
+        Ok(Self {
+            handle,
+            thread: Some(thread),
+            completion,
+        })
+    }
+
+    pub(crate) async fn join(mut self) -> Result<ManagedOutcome, Box<dyn std::error::Error>> {
+        let outcome = (&mut self.completion).await;
+        self.join_thread()?;
+        Ok(outcome
+            .map_err(|_| io::Error::other("managed worker completed without an outcome"))??)
+    }
+
+    fn join_thread(&mut self) -> io::Result<()> {
+        self.thread
+            .take()
+            .expect("managed worker is joined once")
+            .join()
+            .map_err(|_| io::Error::other("managed worker thread panicked"))
+    }
+}
+
+impl Drop for ManagedWorker {
+    fn drop(&mut self) {
+        if self.thread.is_some() {
+            drop(self.handle.stop());
+            let _ = self.join_thread();
+        }
+    }
+}

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

@@ -0,0 +1,2 @@
+#[cfg(any(feature = "client", feature = "tui"))]
+pub mod client;

crates/irtt-app/src/signal.rs

@@ -0,0 +1,22 @@
+#[cfg(feature = "server")]
+use std::sync::{
+    atomic::{AtomicBool, Ordering},
+    Arc,
+};
+
+#[cfg(feature = "server")]
+pub fn install_signal_handler(shutdown_requested: Arc<AtomicBool>) -> Result<(), ctrlc::Error> {
+    ctrlc::set_handler(move || {
+        shutdown_requested.store(true, Ordering::Relaxed);
+    })
+}
+
+/// Preserve ctrlc's SIGINT/SIGTERM policy while waking the async frontends.
+#[cfg(any(feature = "client", feature = "tui"))]
+pub fn install_async_signal_handler() -> Result<tokio::sync::watch::Receiver<bool>, ctrlc::Error> {
+    let (shutdown, receiver) = tokio::sync::watch::channel(false);
+    ctrlc::set_handler(move || {
+        shutdown.send_replace(true);
+    })?;
+    Ok(receiver)
+}

crates/irtt-cli/Cargo.toml

@@ -1,46 +0,0 @@
-[package]
-name = "irtt-cli"
-version = "0.4.0"
-description = "Command-line IRTT-compatible client"
-edition.workspace = true
-license.workspace = true
-rust-version.workspace = true
-repository.workspace = true
-homepage.workspace = true
-readme.workspace = true
-keywords = ["irtt", "networking", "latency", "rtt"]
-categories = ["command-line-utilities", "network-programming"]
-
-[lib]
-doc = false
-
-[[bin]]
-name = "irtt-rs"
-path = "src/bin/irtt-rs.rs"
-
-[[bin]]
-name = "irtt-cli"
-path = "src/bin/irtt-cli.rs"
-required-features = ["client"]
-
-[[bin]]
-name = "irtt-tui"
-path = "src/bin/irtt-tui.rs"
-required-features = ["tui"]
-
-[features]
-default = ["client", "stats"]
-client-runtime = ["dep:irtt-client", "dep:irtt-proto"]
-client = ["client-runtime"]
-stats = ["client-runtime", "dep:irtt-stats"]
-tui = ["client-runtime", "stats", "dep:ratatui", "dep:crossterm"]
-full = ["client", "stats", "tui"]
-
-[dependencies]
-clap = { version = "4.6.1", features = ["derive"] }
-crossterm = { version = "0.29.0", optional = true }
-ctrlc = "3.5.2"
-irtt-client = { workspace = true, optional = true }
-irtt-proto = { workspace = true, optional = true }
-irtt-stats = { workspace = true, optional = true }
-ratatui = { version = "0.30.2", optional = true }

crates/irtt-cli/src/applet.rs

@@ -1,222 +0,0 @@
-use std::{ffi::OsString, path::Path};
-
-use clap::Command;
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub enum RequestedApplet {
-    Client,
-    Tui,
-    Server,
-}
-
-#[derive(Debug, Clone, PartialEq, Eq)]
-pub enum AppletDispatch {
-    Run {
-        applet: RequestedApplet,
-        argv: Vec<OsString>,
-    },
-    Help(String),
-}
-
-pub fn detect_applet_from_argv0(argv0: &str) -> Option<RequestedApplet> {
-    match applet_basename(argv0) {
-        "irtt-cli" => Some(RequestedApplet::Client),
-        "irtt-tui" => Some(RequestedApplet::Tui),
-        "irttd" | "irtt-server" => Some(RequestedApplet::Server),
-        "irtt-rs" => None,
-        _ => None,
-    }
-}
-
-pub fn dispatch_from_argv(argv: Vec<OsString>) -> Result<AppletDispatch, String> {
-    let argv0 = argv
-        .first()
-        .and_then(|arg| arg.to_str())
-        .unwrap_or("irtt-rs");
-
-    if let Some(applet) = detect_applet_from_argv0(argv0) {
-        return Ok(AppletDispatch::Run { applet, argv });
-    }
-
-    let basename = applet_basename(argv0);
-    if basename.starts_with("irtt-") && basename != "irtt-rs" {
-        return Err(format!(
-            "unknown applet name '{basename}'. Known applet names: {}",
-            known_applet_binary_names()
-        ));
-    }
-
-    let Some(command) = argv.get(1).and_then(|arg| arg.to_str()) else {
-        return Err(format!(
-            "choose an applet: {}\n\n{}",
-            applet_command_names(),
-            dispatcher_help()
-        ));
-    };
-
-    match command {
-        "-h" | "--help" => Ok(AppletDispatch::Help(dispatcher_help())),
-        "client" => Ok(AppletDispatch::Run {
-            applet: RequestedApplet::Client,
-            argv: applet_argv("irtt-cli", &argv[2..]),
-        }),
-        "tui" => Ok(AppletDispatch::Run {
-            applet: RequestedApplet::Tui,
-            argv: applet_argv("irtt-tui", &argv[2..]),
-        }),
-        "server" => Ok(AppletDispatch::Run {
-            applet: RequestedApplet::Server,
-            argv: applet_argv("irtt-server", &argv[2..]),
-        }),
-        _ => Err(format!(
-            "unknown applet '{command}'. Choose one of: {}\n\n{}",
-            applet_command_names(),
-            dispatcher_help()
-        )),
-    }
-}
-
-pub fn dispatcher_help() -> String {
-    let mut command = Command::new("irtt-rs")
-        .about("IRTT-compatible multi-applet dispatcher")
-        .subcommand(Command::new("client").about(client_applet_about()))
-        .subcommand(Command::new("tui").about(tui_applet_about()))
-        .subcommand(Command::new("server").about("Server applet is not available in this build"))
-        .after_help(dispatcher_after_help());
-    command.render_help().to_string()
-}
-
-fn client_applet_about() -> &'static str {
-    if cfg!(feature = "client") {
-        "Run the stream client applet"
-    } else {
-        "Stream client applet is not available in this build"
-    }
-}
-
-fn tui_applet_about() -> &'static str {
-    if cfg!(feature = "tui") {
-        "Run the terminal UI applet"
-    } else {
-        "Terminal UI applet is not available in this build"
-    }
-}
-
-fn known_applet_binary_names() -> &'static str {
-    "irtt-rs, irtt-cli, irtt-tui, irtt-server"
-}
-
-fn applet_command_names() -> &'static str {
-    "client, tui, or server"
-}
-
-fn dispatcher_after_help() -> &'static str {
-    if cfg!(feature = "tui") {
-        "Recognized applet binary names: irtt-cli, irtt-tui, irtt-server"
-    } else if cfg!(feature = "client") {
-        "Recognized applet binary names: irtt-cli, irtt-tui, irtt-server\nOptional applet: irtt-tui requires the tui feature"
-    } else {
-        "Recognized applet binary names: irtt-cli, irtt-tui, irtt-server\nOptional applets: irtt-cli requires the client feature; irtt-tui requires the tui feature"
-    }
-}
-
-fn applet_basename(argv0: &str) -> &str {
-    Path::new(argv0)
-        .file_name()
-        .and_then(|name| name.to_str())
-        .unwrap_or(argv0)
-}
-
-fn applet_argv(applet_name: &str, args: &[OsString]) -> Vec<OsString> {
-    let mut argv = Vec::with_capacity(args.len() + 1);
-    argv.push(OsString::from(applet_name));
-    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-cli"),
-            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 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"));
-    }
-
-    #[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-cli".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-cli"));
-        if cfg!(feature = "tui") {
-            assert!(err.contains("irtt-tui"));
-        }
-        assert!(err.contains("irtt-server"));
-    }
-}

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

@@ -1,319 +0,0 @@
-use std::time::Duration;
-
-use clap::{Parser, ValueEnum};
-use irtt_client::ClientConfig;
-
-use crate::shared::client::{
-    parse_labelled_target, parse_test_duration, resolved_managed_targets, target_specs,
-    CommonClientArgs, GroupPacingArg, LabelledTargetArg, ResolvedTarget, TargetSpec, TimestampArg,
-};
-
-pub const DEFAULT_CLIENT_DURATION: Duration = Duration::from_secs(10);
-
-#[derive(Debug, Clone, Parser)]
-#[command(name = "irtt-cli", about = "Minimal IRTT-compatible stream client")]
-pub struct ClientArgs {
-    /// Server address or host, with optional port. Repeat for multi-target mode.
-    #[arg(
-        value_name = "TARGET",
-        num_args = 0..,
-        long_help = "Server address or host, with optional port. Repeat the positional target for multi-target mode, for example: irtt-cli host-a:2112 host-b:2112."
-    )]
-    pub targets: Vec<String>,
-
-    /// Explicit labelled target, as label=host:port. Repeat for multi-target mode.
-    #[arg(
-        long = "target",
-        value_name = "LABEL=TARGET",
-        value_parser = parse_labelled_target,
-        long_help = "Explicit labelled target, as label=host:port. Repeat for multi-target mode. The label is used as the target column and must be unique."
-    )]
-    pub labelled_targets: Vec<LabelledTargetArg>,
-
-    /// Managed group pacing for multi-target mode.
-    #[arg(
-        long,
-        value_enum,
-        default_value_t = GroupPacingArg::Staggered,
-        long_help = "Managed group pacing for multi-target mode.\n\nstaggered spaces active targets across the probe interval. burst sends one probe to every active target back-to-back once per interval."
-    )]
-    pub pacing: GroupPacingArg,
-
-    #[arg(
-        long,
-        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."
-    )]
-    pub duration: Duration,
-
-    #[command(flatten)]
-    pub common: CommonClientArgs,
-
-    /// Event row output format.
-    #[arg(
-        long,
-        value_enum,
-        default_value_t = OutputFormat::Table,
-        long_help = "Event row output format.\n\nTable is the default interactive format. CSV, TSV, and JSON Lines default to all columns for structured export."
-    )]
-    pub format: OutputFormat,
-
-    /// Comma-separated event row columns, or default/all.
-    #[arg(
-        short = 'c',
-        long,
-        value_name = "COLUMNS",
-        long_help = "Comma-separated event row columns, or default/all.\n\nThe default table columns are compact and hide echo_sent rows. Custom table columns include all event rows. Run --list-columns to see valid names."
-    )]
-    pub columns: Option<String>,
-
-    /// List available event row columns and aliases, then exit.
-    #[arg(
-        long,
-        long_help = "List available event row columns and aliases, then exit.\n\nA server argument is not required when listing columns."
-    )]
-    pub list_columns: bool,
-
-    /// Header policy for table, CSV, and TSV output.
-    #[arg(
-        long,
-        value_enum,
-        default_value_t = HeaderMode::Auto,
-        long_help = "Header policy for table, CSV, and TSV output.\n\nJSON Lines never prints a header."
-    )]
-    pub header: HeaderMode,
-
-    /// Include extra fields in table output and final summaries.
-    #[arg(long)]
-    pub verbose: bool,
-}
-
-impl ClientArgs {
-    pub fn to_client_config(&self) -> ClientConfig {
-        self.common.to_client_config(
-            self.primary_target_addr()
-                .expect("target is required unless --list-columns is set"),
-            self.duration,
-        )
-    }
-
-    pub fn is_continuous(&self) -> bool {
-        self.duration == Duration::ZERO
-    }
-
-    pub fn timestamp_mode(&self) -> TimestampArg {
-        self.common.tstamp
-    }
-
-    pub fn target_specs(&self) -> Result<Vec<CliTargetSpec>, String> {
-        target_specs(&self.targets, &self.labelled_targets)
-    }
-
-    pub fn resolved_managed_targets(&self) -> Result<Vec<ResolvedCliTarget>, String> {
-        let specs = self.target_specs()?;
-        let config = self.to_client_config();
-        resolved_managed_targets(specs, &config)
-    }
-
-    fn primary_target_addr(&self) -> Option<&str> {
-        self.targets.first().map(String::as_str).or_else(|| {
-            self.labelled_targets
-                .first()
-                .map(|target| target.addr.as_str())
-        })
-    }
-}
-
-impl std::ops::Deref for ClientArgs {
-    type Target = CommonClientArgs;
-
-    fn deref(&self) -> &Self::Target {
-        &self.common
-    }
-}
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq, ValueEnum)]
-pub enum OutputFormat {
-    /// Readable terminal table output.
-    Table,
-    /// Comma-separated event rows.
-    Csv,
-    /// Tab-separated event rows.
-    Tsv,
-    /// One JSON object per event row.
-    Jsonl,
-}
-
-pub type CliTargetSpec = TargetSpec;
-pub type ResolvedCliTarget = ResolvedTarget;
-
-impl OutputFormat {
-    pub fn prints_summary(self) -> bool {
-        matches!(self, Self::Table)
-    }
-}
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq, ValueEnum)]
-pub enum HeaderMode {
-    /// Print headers for table, CSV, and TSV output.
-    Auto,
-    /// Always print headers where the format supports them.
-    Always,
-    /// 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-cli"];
-        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, ["127.0.0.1:2112"]);
-        assert!(args.labelled_targets.is_empty());
-        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.to_client_config();
-        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);
-    }
-
-    #[test]
-    fn multiple_positional_targets_parse_as_targets() {
-        let args = parse(&["host-a:2112", "host-b:2112"]).unwrap();
-        let specs = args.target_specs().unwrap();
-
-        assert_eq!(specs[0].label, "host-a:2112");
-        assert_eq!(specs[0].addr, "host-a:2112");
-        assert_eq!(specs[1].label, "host-b:2112");
-        assert_eq!(specs[1].addr, "host-b:2112");
-    }
-
-    #[test]
-    fn repeated_labelled_targets_parse() {
-        let args = parse(&[
-            "--target",
-            "ams=ams.example.com:2112",
-            "--target",
-            "sg=sg.example.com:2112",
-        ])
-        .unwrap();
-        let specs = args.target_specs().unwrap();
-
-        assert_eq!(specs[0].label, "ams");
-        assert_eq!(specs[0].addr, "ams.example.com:2112");
-        assert_eq!(specs[1].label, "sg");
-        assert_eq!(specs[1].addr, "sg.example.com:2112");
-    }
-
-    #[test]
-    fn duplicate_labels_are_rejected() {
-        let args = parse(&["host-a:2112", "--target", "host-a:2112=host-b:2112"]).unwrap();
-        let err = args.target_specs().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.target_specs().unwrap();
-
-        assert_eq!(specs[0].label, "host-a:2112");
-        assert_eq!(specs[1].label, "host-a:2112#2");
-    }
-
-    #[test]
-    fn duplicate_resolved_target_addresses_are_rejected() {
-        let args = parse(&["127.0.0.1:2112", "127.0.0.1"]).unwrap();
-        let err = args.resolved_managed_targets().unwrap_err();
-
-        assert!(err.contains("duplicate resolved target address 127.0.0.1:2112"));
-    }
-
-    #[test]
-    fn invalid_labelled_target_syntax_is_rejected() {
-        assert!(parse(&["--target", "missing-equals"]).is_err());
-        assert!(parse(&["--target", "=127.0.0.1:2112"]).is_err());
-        assert!(parse(&["--target", "label="]).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 <LABEL=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 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-cli/src/cmd/client/run.rs

@@ -1,766 +0,0 @@
-#[cfg(feature = "stats")]
-use std::collections::BTreeMap;
-use std::{
-    collections::HashSet,
-    io::{self, Write},
-    sync::atomic::AtomicBool,
-    thread,
-    time::{Duration, Instant},
-};
-
-use irtt_client::{
-    ClientEvent, EventSubscriptionError, ManagedClientGroup, ManagedClientGroupConfig,
-    ManagedGroupEndReason, SubscriberConfig, SubscriberOverflow, TargetEvent,
-};
-#[cfg(all(test, feature = "stats"))]
-use irtt_client::{ClientTimestamp, PacketMeta, RttSample, SignedDuration};
-
-use super::{
-    args::{ClientArgs, ResolvedCliTarget},
-    output::{EventRenderStats, OutputConfig},
-};
-#[cfg(feature = "stats")]
-use crate::shared::client::expected_probe_count;
-use crate::shared::client::{
-    is_shutdown_requested, session::should_print_final_summary, ClientSession,
-};
-
-#[cfg(feature = "stats")]
-use irtt_stats::{StatsCollector, StatsConfig};
-
-#[cfg(feature = "stats")]
-const FINITE_STATS_BYTES_PER_PROBE: u64 = 500;
-#[cfg(feature = "stats")]
-const MIB: u64 = 1024 * 1024;
-#[cfg(feature = "stats")]
-const GIB: u64 = 1024 * MIB;
-#[cfg(feature = "stats")]
-const FINITE_STATS_MEMORY_WARNING_BYTES: u64 = 128 * MIB;
-#[cfg(feature = "stats")]
-const FINITE_STATS_MEMORY_STRONG_WARNING_BYTES: u64 = 512 * MIB;
-#[cfg(feature = "stats")]
-const FINITE_STATS_MEMORY_VERY_STRONG_WARNING_BYTES: u64 = GIB;
-
-const GROUP_IDLE_SLEEP: Duration = Duration::from_millis(5);
-const GROUP_COMPLETION_GRACE: Duration = Duration::from_secs(1);
-
-pub fn run_stream(
-    args: ClientArgs,
-    shutdown_requested: &AtomicBool,
-) -> Result<(), Box<dyn std::error::Error>> {
-    if args.list_columns {
-        print!("{}", OutputConfig::list_columns());
-        return Ok(());
-    }
-    let output_config = OutputConfig::new(
-        args.format,
-        args.columns.as_deref(),
-        args.header,
-        args.verbose,
-        args.target_specs()
-            .map(|targets| targets.len() > 1)
-            .unwrap_or(false),
-    )
-    .map_err(|err| io::Error::new(io::ErrorKind::InvalidInput, err))?;
-
-    let targets = args
-        .resolved_managed_targets()
-        .map_err(|err| io::Error::new(io::ErrorKind::InvalidInput, err))?;
-    let multi_target = targets.len() > 1;
-
-    let continuous = args.is_continuous();
-    #[cfg(feature = "stats")]
-    if let Some(warning) = finite_stats_memory_warning(&args) {
-        eprintln!("{warning}");
-    }
-
-    if multi_target {
-        return run_group_stream(args, targets, output_config, continuous, shutdown_requested);
-    }
-
-    let target_label = targets
-        .first()
-        .map(|target| target.label.as_str())
-        .expect("at least one target was validated");
-    let mut stdout = io::LineWriter::new(io::stdout().lock());
-    #[cfg(feature = "stats")]
-    let mut stats = StatsCollector::new(stats_config(continuous));
-    let mut stream_output = StreamOutput {
-        config: output_config,
-        header_printed: false,
-        print_final_summary: false,
-        show_running_only_summary_note: false,
-        out: &mut stdout,
-    };
-
-    if is_shutdown_requested(shutdown_requested) {
-        return Ok(());
-    }
-
-    let mut session = ClientSession::connect(args.to_client_config(), continuous)?;
-
-    if is_shutdown_requested(shutdown_requested) {
-        return Ok(());
-    }
-
-    let events = session.open()?;
-    #[cfg(feature = "stats")]
-    print_events_with_stats(&mut stream_output, &events, Some(target_label), &mut stats)?;
-    #[cfg(not(feature = "stats"))]
-    print_events_with_stats(&mut stream_output, &events, Some(target_label))?;
-
-    let mut interrupted = false;
-    while session.should_continue(shutdown_requested) {
-        let events = session.step(shutdown_requested)?;
-        #[cfg(feature = "stats")]
-        print_events_with_stats(&mut stream_output, &events, Some(target_label), &mut stats)?;
-        #[cfg(not(feature = "stats"))]
-        print_events_with_stats(&mut stream_output, &events, Some(target_label))?;
-
-        if is_shutdown_requested(shutdown_requested) {
-            interrupted = true;
-            break;
-        }
-
-        session.sleep_until_next_send();
-    }
-    interrupted |= is_shutdown_requested(shutdown_requested);
-
-    if interrupted {
-        eprintln!("interrupted, closing session...");
-    }
-
-    if session.should_drain_final(interrupted) {
-        session.drain_final(|events| {
-            #[cfg(feature = "stats")]
-            let _ =
-                print_events_with_stats(&mut stream_output, events, Some(target_label), &mut stats);
-            #[cfg(not(feature = "stats"))]
-            let _ = print_events_with_stats(&mut stream_output, events, Some(target_label));
-        })?;
-    }
-
-    let events = session.poll_timeouts()?;
-    #[cfg(feature = "stats")]
-    print_events_with_stats(&mut stream_output, &events, Some(target_label), &mut stats)?;
-    #[cfg(not(feature = "stats"))]
-    print_events_with_stats(&mut stream_output, &events, Some(target_label))?;
-
-    let events = session.close()?;
-    #[cfg(feature = "stats")]
-    print_events_with_stats(&mut stream_output, &events, Some(target_label), &mut stats)?;
-    #[cfg(not(feature = "stats"))]
-    print_events_with_stats(&mut stream_output, &events, Some(target_label))?;
-    let print_final_summary = should_print_final_summary(continuous, interrupted);
-    stream_output.print_final_summary = print_final_summary;
-    stream_output.show_running_only_summary_note = continuous && interrupted && print_final_summary;
-    #[cfg(feature = "stats")]
-    stream_output.print_summary(&stats)?;
-    #[cfg(not(feature = "stats"))]
-    stream_output.print_summary()?;
-    stream_output.out.flush()?;
-    Ok(())
-}
-
-struct StreamOutput<'a, W: Write> {
-    config: OutputConfig,
-    header_printed: bool,
-    print_final_summary: bool,
-    show_running_only_summary_note: bool,
-    out: &'a mut W,
-}
-
-impl<W: Write> StreamOutput<'_, W> {
-    fn print_events(
-        &mut self,
-        events: &[ClientEvent],
-        target: Option<&str>,
-        stats_updates: &[EventRenderStats],
-    ) -> io::Result<()> {
-        self.print_header()?;
-        for (event, stats_update) in events.iter().zip(stats_updates) {
-            self.print_event(event, target, stats_update)?;
-        }
-        Ok(())
-    }
-
-    fn print_event(
-        &mut self,
-        event: &ClientEvent,
-        target: Option<&str>,
-        stats_update: &EventRenderStats,
-    ) -> io::Result<()> {
-        if let Some(line) = self.config.render_event(event, target, Some(stats_update)) {
-            writeln!(self.out, "{line}")?;
-        }
-        Ok(())
-    }
-
-    fn print_header(&mut self) -> io::Result<()> {
-        if self.header_printed {
-            return Ok(());
-        }
-        self.header_printed = true;
-        if let Some(header) = self.config.render_header() {
-            writeln!(self.out, "{header}")?;
-        }
-        Ok(())
-    }
-
-    #[cfg(feature = "stats")]
-    fn print_summary(&mut self, stats: &StatsCollector) -> io::Result<()> {
-        if !self.print_final_summary || !self.config.prints_summary() {
-            return Ok(());
-        }
-
-        write!(
-            self.out,
-            "{}",
-            crate::cmd::client::summary::format_summary_with_options(
-                &stats.snapshot(),
-                crate::cmd::client::summary::SummaryFormatOptions {
-                    verbose: self.config.summary_verbose(),
-                    show_running_only_note: self.show_running_only_summary_note,
-                },
-            )
-        )?;
-
-        Ok(())
-    }
-
-    #[cfg(not(feature = "stats"))]
-    fn print_summary(&mut self) -> io::Result<()> {
-        Ok(())
-    }
-}
-
-#[cfg(feature = "stats")]
-fn print_events_with_stats<W: Write>(
-    stream_output: &mut StreamOutput<'_, W>,
-    events: &[ClientEvent],
-    target: Option<&str>,
-    stats: &mut StatsCollector,
-) -> io::Result<()> {
-    let stats_updates = events
-        .iter()
-        .map(|event| EventRenderStats::from(stats.process(event)))
-        .collect::<Vec<_>>();
-    stream_output.print_events(events, target, &stats_updates)
-}
-
-#[cfg(not(feature = "stats"))]
-fn print_events_with_stats<W: Write>(
-    stream_output: &mut StreamOutput<'_, W>,
-    events: &[ClientEvent],
-    target: Option<&str>,
-) -> io::Result<()> {
-    let stats_updates = vec![EventRenderStats::default(); events.len()];
-    stream_output.print_events(events, target, &stats_updates)
-}
-
-fn run_group_stream(
-    args: ClientArgs,
-    targets: Vec<ResolvedCliTarget>,
-    output_config: OutputConfig,
-    continuous: bool,
-    shutdown_requested: &AtomicBool,
-) -> Result<(), Box<dyn std::error::Error>> {
-    let mut config = args.to_client_config();
-    let managed_targets = targets
-        .iter()
-        .map(|target| target.managed.clone())
-        .collect::<Vec<_>>();
-    let expected_target_count = managed_targets.len();
-    if let Some(first) = managed_targets.first() {
-        config.server_addr = first.remote.to_string();
-    }
-
-    let group_config = ManagedClientGroupConfig {
-        client: config,
-        pacing: args.pacing.into(),
-    };
-
-    let (session, events) = ManagedClientGroup::start_with_subscription(
-        group_config,
-        managed_targets,
-        SubscriberConfig {
-            capacity: 16_384,
-            // CLI output is best-effort under sustained backpressure. Dropping
-            // stale rows keeps continuous runs attached to the running group
-            // instead of turning a full output queue into a disconnected
-            // subscriber and a potentially blocking join.
-            overflow: SubscriberOverflow::DropOldest,
-        },
-    )?;
-
-    let mut stdout = io::LineWriter::new(io::stdout().lock());
-    #[cfg(feature = "stats")]
-    let mut stats = targets
-        .iter()
-        .map(|target| {
-            (
-                target.label.clone(),
-                StatsCollector::new(stats_config(continuous)),
-            )
-        })
-        .collect::<BTreeMap<_, _>>();
-    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 interrupted = false;
-    let mut terminal_targets = HashSet::new();
-    let mut last_event_at = Instant::now();
-    let mut saw_target_event = false;
-
-    loop {
-        if is_shutdown_requested(shutdown_requested) {
-            interrupted = true;
-            session.stop();
-        }
-
-        match events.try_recv() {
-            Ok(Some(target_event)) => {
-                last_event_at = Instant::now();
-                saw_target_event = true;
-                let label = target_event.target.as_str();
-                if is_terminal_target_event(&target_event.event) {
-                    terminal_targets.insert(label.to_owned());
-                }
-                #[cfg(feature = "stats")]
-                {
-                    let stats = stats
-                        .entry(label.to_owned())
-                        .or_insert_with(|| StatsCollector::new(stats_config(continuous)));
-                    print_target_event_with_stats(&mut stream_output, &target_event, stats)?;
-                }
-                #[cfg(not(feature = "stats"))]
-                {
-                    print_target_event_with_stats(&mut stream_output, &target_event)?;
-                }
-            }
-            Ok(None) => {
-                if interrupted {
-                    break;
-                }
-                if terminal_targets.len() >= expected_target_count {
-                    break;
-                }
-                if should_join_group_after_idle(&args, continuous, saw_target_event, last_event_at)
-                {
-                    break;
-                }
-                thread::sleep(GROUP_IDLE_SLEEP);
-            }
-            Err(EventSubscriptionError::Disconnected) => break,
-        }
-    }
-
-    if interrupted {
-        eprintln!("interrupted, closing group...");
-    }
-
-    let outcome = session.join()?;
-    while let Ok(Some(target_event)) = events.try_recv() {
-        let label = target_event.target.as_str();
-        #[cfg(feature = "stats")]
-        {
-            let stats = stats
-                .entry(label.to_owned())
-                .or_insert_with(|| StatsCollector::new(stats_config(continuous)));
-            print_target_event_with_stats(&mut stream_output, &target_event, stats)?;
-        }
-        #[cfg(not(feature = "stats"))]
-        {
-            print_target_event_with_stats(&mut stream_output, &target_event)?;
-        }
-    }
-
-    if outcome.end_reason == ManagedGroupEndReason::Cancelled && !interrupted {
-        return Err("managed client group was cancelled".into());
-    }
-
-    let print_final_summary = should_print_final_summary(continuous, interrupted);
-    stream_output.print_final_summary = print_final_summary;
-    stream_output.show_running_only_summary_note = continuous && interrupted && print_final_summary;
-    #[cfg(feature = "stats")]
-    {
-        for (label, stats) in &stats {
-            if stream_output.print_final_summary && stream_output.config.prints_summary() {
-                writeln!(stream_output.out)?;
-                writeln!(stream_output.out, "target: {label}")?;
-            }
-            stream_output.print_summary(stats)?;
-        }
-    }
-    #[cfg(not(feature = "stats"))]
-    {
-        stream_output.print_summary()?;
-    }
-    stream_output.out.flush()?;
-    Ok(())
-}
-
-fn is_terminal_target_event(event: &ClientEvent) -> bool {
-    matches!(
-        event,
-        ClientEvent::SessionClosed { .. } | ClientEvent::NoTestCompleted { .. }
-    )
-}
-
-fn estimated_group_completion_grace(args: &ClientArgs) -> Duration {
-    let open_timeout: Duration = args.to_client_config().open_timeouts.iter().sum();
-    open_timeout
-        .saturating_add(args.duration)
-        .saturating_add(GROUP_COMPLETION_GRACE)
-}
-
-fn should_join_group_after_idle(
-    args: &ClientArgs,
-    continuous: bool,
-    saw_target_event: bool,
-    last_event_at: Instant,
-) -> bool {
-    if continuous && saw_target_event {
-        return false;
-    }
-    last_event_at.elapsed() > estimated_group_completion_grace(args)
-}
-
-#[cfg(feature = "stats")]
-fn print_target_event_with_stats<W: Write>(
-    stream_output: &mut StreamOutput<'_, W>,
-    target_event: &TargetEvent,
-    stats: &mut StatsCollector,
-) -> io::Result<()> {
-    print_events_with_stats(
-        stream_output,
-        std::slice::from_ref(&target_event.event),
-        Some(target_event.target.as_str()),
-        stats,
-    )
-}
-
-#[cfg(not(feature = "stats"))]
-fn print_target_event_with_stats<W: Write>(
-    stream_output: &mut StreamOutput<'_, W>,
-    target_event: &TargetEvent,
-) -> io::Result<()> {
-    print_events_with_stats(
-        stream_output,
-        std::slice::from_ref(&target_event.event),
-        Some(target_event.target.as_str()),
-    )
-}
-
-#[cfg(feature = "stats")]
-fn stats_config(continuous: bool) -> StatsConfig {
-    if continuous {
-        StatsConfig::continuous()
-    } else {
-        StatsConfig::finite()
-    }
-}
-
-#[cfg(feature = "stats")]
-fn estimate_finite_stats_memory_bytes(expected_probes: u64) -> u64 {
-    expected_probes.saturating_mul(FINITE_STATS_BYTES_PER_PROBE)
-}
-
-#[cfg(feature = "stats")]
-fn finite_stats_memory_warning(args: &ClientArgs) -> Option<String> {
-    if args.is_continuous() || args.duration.is_zero() {
-        return None;
-    }
-
-    let expected_probes = expected_probe_count(args.duration, args.interval);
-    let estimated_bytes = estimate_finite_stats_memory_bytes(expected_probes);
-    if estimated_bytes < FINITE_STATS_MEMORY_WARNING_BYTES {
-        return None;
-    }
-
-    let formatted = format_bytes_for_warning(estimated_bytes);
-    let guidance = if estimated_bytes >= FINITE_STATS_MEMORY_VERY_STRONG_WARNING_BYTES {
-        "this may be unsuitable on memory-constrained systems"
-    } else if estimated_bytes >= FINITE_STATS_MEMORY_STRONG_WARNING_BYTES {
-        "consider shortening the run, increasing the interval, or using continuous mode"
-    } else {
-        "use continuous mode for bounded-memory long-running tests"
-    };
-
-    Some(format!(
-        "irtt-rs: warning: finite exact statistics may retain about {formatted} for this run; {guidance}"
-    ))
-}
-
-#[cfg(feature = "stats")]
-fn format_bytes_for_warning(bytes: u64) -> String {
-    if bytes >= GIB {
-        format!("{} GiB", bytes.saturating_add(GIB / 2) / GIB)
-    } else {
-        format!("{} MiB", bytes.saturating_add(MIB / 2) / MIB)
-    }
-}
-
-#[cfg(all(test, feature = "stats"))]
-mod tests {
-    use super::*;
-    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)
-    }
-
-    fn reply_event(seq: u32, rtt_us: u64) -> ClientEvent {
-        let sent_at = test_timestamp(Duration::from_millis(seq as u64));
-        let received_at = ClientTimestamp {
-            wall: sent_at.wall + Duration::from_micros(rtt_us),
-            mono: sent_at.mono + Duration::from_micros(rtt_us),
-        };
-        ClientEvent::EchoReply {
-            seq,
-            remote: test_remote(),
-            sent_at,
-            received_at,
-            rtt: RttSample {
-                raw: Duration::from_micros(rtt_us),
-                adjusted: None,
-                effective: SignedDuration::from_nanos(i128::from(rtt_us) * 1_000),
-            },
-            server_timing: None,
-            one_way: None,
-            received_stats: None,
-            bytes: 64,
-            packet_meta: PacketMeta::default(),
-        }
-    }
-
-    fn cli_args(args: &[&str]) -> ClientArgs {
-        let mut argv = vec!["irtt-rs"];
-        argv.extend_from_slice(args);
-        <ClientArgs as clap::Parser>::try_parse_from(argv).unwrap()
-    }
-
-    fn output_config(
-        format: crate::cmd::client::OutputFormat,
-        columns: Option<&str>,
-        header: crate::cmd::client::HeaderMode,
-        verbose: bool,
-    ) -> OutputConfig {
-        OutputConfig::new(format, columns, header, verbose, false).unwrap()
-    }
-
-    #[test]
-    fn output_helper_streams_and_collects_events() {
-        let sent_at = test_timestamp(Duration::from_secs(1));
-        let received_at = test_timestamp(Duration::from_secs(1) + Duration::from_micros(1200));
-        let events = [
-            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::ZERO,
-            },
-            ClientEvent::EchoReply {
-                seq: 1,
-                remote: test_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(),
-            },
-        ];
-
-        let mut stats = StatsCollector::new(StatsConfig::finite());
-        let mut out = Vec::new();
-        {
-            let mut stream_output = StreamOutput {
-                config: output_config(
-                    crate::cmd::client::OutputFormat::Tsv,
-                    Some("effective_rtt_us"),
-                    crate::cmd::client::HeaderMode::Never,
-                    false,
-                ),
-                header_printed: false,
-                print_final_summary: true,
-                show_running_only_summary_note: false,
-                out: &mut out,
-            };
-            print_events_with_stats(&mut stream_output, &events, None, &mut stats).unwrap();
-            stream_output.print_summary(&stats).unwrap();
-        }
-
-        let rendered = String::from_utf8(out).unwrap();
-        let summary = stats.snapshot();
-        assert!(!rendered.is_empty());
-        assert_eq!(summary.packets.packets_sent, 1);
-        assert_eq!(summary.packets.unique_replies, 1);
-    }
-
-    #[test]
-    fn continuous_summary_prints_when_enabled_and_suppresses_when_disabled() {
-        let mut stats = StatsCollector::new(StatsConfig::continuous());
-        let mut out = Vec::new();
-        {
-            let mut stream_output = StreamOutput {
-                config: output_config(
-                    crate::cmd::client::OutputFormat::Table,
-                    None,
-                    crate::cmd::client::HeaderMode::Auto,
-                    false,
-                ),
-                header_printed: false,
-                print_final_summary: true,
-                show_running_only_summary_note: true,
-                out: &mut out,
-            };
-            print_events_with_stats(
-                &mut stream_output,
-                &[reply_event(1, 1200)],
-                None,
-                &mut stats,
-            )
-            .unwrap();
-            stream_output.print_summary(&stats).unwrap();
-        }
-
-        let rendered = String::from_utf8(out).unwrap();
-        assert!(rendered.contains("irtt-rs summary"));
-        assert!(rendered.contains("medians unavailable"));
-        assert!(rendered.contains("continuous mode"));
-        assert!(rendered.contains("packets:"));
-        assert!(rendered.contains("received=1"));
-
-        let stats = StatsCollector::new(StatsConfig::continuous());
-        let mut out = Vec::new();
-        {
-            let mut stream_output = StreamOutput {
-                config: output_config(
-                    crate::cmd::client::OutputFormat::Table,
-                    None,
-                    crate::cmd::client::HeaderMode::Auto,
-                    false,
-                ),
-                header_printed: false,
-                print_final_summary: false,
-                show_running_only_summary_note: true,
-                out: &mut out,
-            };
-            stream_output.print_summary(&stats).unwrap();
-        }
-
-        assert!(out.is_empty());
-    }
-
-    #[test]
-    fn continuous_mode_uses_continuous_stats_config() {
-        let mut collector = StatsCollector::new(stats_config(true));
-        for seq in 0..5000_u32 {
-            let sent_at = test_timestamp(Duration::from_micros(seq as u64));
-            let received_at = test_timestamp(Duration::from_micros(seq as u64 + 1));
-            collector.process(&ClientEvent::EchoReply {
-                seq,
-                remote: test_remote(),
-                sent_at,
-                received_at,
-                rtt: RttSample {
-                    raw: Duration::from_micros(1),
-                    adjusted: None,
-                    effective: SignedDuration::from_nanos(1_000),
-                },
-                server_timing: None,
-                one_way: None,
-                received_stats: None,
-                bytes: 64,
-                packet_meta: PacketMeta::default(),
-            });
-        }
-
-        assert_eq!(collector.snapshot().rtt.primary.median_ns, None);
-    }
-
-    #[test]
-    fn finite_stats_memory_warning_reports_only_large_finite_runs() {
-        for args in [
-            cli_args(&["--duration", "0", "--interval", "1ms", "127.0.0.1:2112"]),
-            cli_args(&[
-                "--duration",
-                "1000ms",
-                "--interval",
-                "1ms",
-                "127.0.0.1:2112",
-            ]),
-        ] {
-            assert_eq!(finite_stats_memory_warning(&args), None);
-        }
-
-        for (threshold, size, guidance) in [
-            (
-                FINITE_STATS_MEMORY_WARNING_BYTES,
-                "about 128 MiB",
-                "bounded-memory long-running tests",
-            ),
-            (
-                FINITE_STATS_MEMORY_STRONG_WARNING_BYTES,
-                "about 512 MiB",
-                "shortening the run",
-            ),
-            (
-                FINITE_STATS_MEMORY_VERY_STRONG_WARNING_BYTES,
-                "about 1 GiB",
-                "memory-constrained systems",
-            ),
-        ] {
-            let expected_probes = threshold.div_ceil(FINITE_STATS_BYTES_PER_PROBE);
-            let args = cli_args(&[
-                "--duration",
-                &format!("{expected_probes}ms"),
-                "--interval",
-                "1ms",
-                "127.0.0.1:2112",
-            ]);
-
-            let warning = finite_stats_memory_warning(&args).unwrap();
-            assert!(warning.contains(size));
-            assert!(warning.contains(guidance));
-        }
-    }
-
-    #[test]
-    fn expected_probe_count_rounds_up() {
-        assert_eq!(
-            expected_probe_count(Duration::from_millis(1001), Duration::from_secs(1)),
-            2
-        );
-    }
-
-    #[test]
-    fn estimate_finite_stats_memory_bytes_saturates() {
-        assert_eq!(estimate_finite_stats_memory_bytes(u64::MAX), u64::MAX);
-    }
-}

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

@@ -1,309 +0,0 @@
-use std::fmt::Write as _;
-
-use irtt_stats::{Snapshot, TimeStats};
-
-pub fn format_summary(summary: &Snapshot) -> String {
-    format_summary_with_options(summary, SummaryFormatOptions::default())
-}
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
-pub struct SummaryFormatOptions {
-    pub verbose: bool,
-    pub show_running_only_note: bool,
-}
-
-pub fn format_summary_with_options(summary: &Snapshot, options: SummaryFormatOptions) -> String {
-    let mut out = String::new();
-    let packets = summary.packets;
-    let loss = summary.loss;
-
-    writeln!(out).unwrap();
-    writeln!(out, "irtt-rs summary").unwrap();
-    if options.show_running_only_note {
-        writeln!(
-            out,
-            "note: medians unavailable in continuous mode; running statistics are bounded-memory"
-        )
-        .unwrap();
-    }
-    writeln!(out).unwrap();
-    writeln!(
-        out,
-        "  {:<18} {:>7} {:>10} {:>10} {:>10} {:>10} {:>10}",
-        "Metric", "Count", "Min", "Mean", "Median", "Max", "Stddev"
-    )
-    .unwrap();
-    writeln!(out, "  {}", "-".repeat(82)).unwrap();
-
-    write_time_row(&mut out, "RTT", &summary.rtt.primary);
-    if options.verbose {
-        write_time_row(&mut out, "raw RTT", &summary.rtt.raw);
-        write_time_row(&mut out, "adjusted RTT", &summary.rtt.adjusted);
-    }
-    write_time_row(&mut out, "IPDV/jitter", &summary.ipdv.round_trip);
-    write_time_row(&mut out, "send IPDV", &summary.ipdv.send);
-    write_time_row(&mut out, "receive IPDV", &summary.ipdv.receive);
-    write_time_row(&mut out, "send delay", &summary.one_way_delay.send_delay);
-    write_time_row(
-        &mut out,
-        "receive delay",
-        &summary.one_way_delay.receive_delay,
-    );
-    write_time_row(
-        &mut out,
-        "server processing",
-        &summary.server_processing.processing,
-    );
-    write_time_row(&mut out, "send call", &summary.send_call);
-    write_time_row(&mut out, "timer error", &summary.timer_error);
-
-    writeln!(out).unwrap();
-    writeln!(
-        out,
-        "packets: sent={} received={} unique={} lost={} loss={}",
-        packets.packets_sent,
-        packets.packets_received,
-        packets.unique_replies,
-        loss.lost_packets,
-        format_percent(loss.packet_loss_percent)
-    )
-    .unwrap();
-    if packets.duplicates != 0 || packets.late_packets != 0 {
-        writeln!(
-            out,
-            "replies: duplicates={} ({}) late={} ({})",
-            packets.duplicates,
-            format_percent(loss.duplicate_percent),
-            packets.late_packets,
-            format_percent(loss.late_packets_percent)
-        )
-        .unwrap();
-    }
-    writeln!(
-        out,
-        "bytes: sent={} received={}",
-        packets.bytes_sent, packets.bytes_received
-    )
-    .unwrap();
-
-    if packets.server_packets_received.is_some() || packets.server_received_window.is_some() {
-        write!(out, "server:").unwrap();
-        if let Some(count) = packets.server_packets_received {
-            write!(out, " received={count}").unwrap();
-        }
-        if let Some(window) = packets.server_received_window {
-            write!(out, " window={window:#x}").unwrap();
-        }
-        writeln!(out).unwrap();
-    }
-
-    out
-}
-
-fn write_time_row(out: &mut String, label: &str, value: &TimeStats) {
-    if value.count == 0 {
-        return;
-    }
-    writeln!(
-        out,
-        "  {label:<18} {:>7} {:>10} {:>10} {:>10} {:>10} {:>10}",
-        value.count,
-        format_ns_i128(value.min_ns),
-        format_ns_f64(value.mean_ns),
-        format_ns_f64_opt(value.median_ns),
-        format_ns_i128(value.max_ns),
-        format_ns_f64(value.stddev_ns())
-    )
-    .unwrap();
-}
-
-fn format_percent(value: f64) -> String {
-    format!("{value:.2}%")
-}
-
-fn format_ns_i128(value: Option<i128>) -> String {
-    value
-        .map(|value| format_ns_f64(value as f64))
-        .unwrap_or_else(|| "-".to_owned())
-}
-
-fn format_ns_f64_opt(value: Option<f64>) -> String {
-    value.map(format_ns_f64).unwrap_or_else(|| "-".to_owned())
-}
-
-fn format_ns_f64(value: f64) -> String {
-    let sign = if value.is_sign_negative() { "-" } else { "" };
-    let value = value.abs();
-    if value < 1_000.0 {
-        format!("{sign}{value:.0}ns")
-    } else if value < 1_000_000.0 {
-        format!("{sign}{:.1}µs", value / 1_000.0)
-    } else if value < 1_000_000_000.0 {
-        format!("{sign}{:.1}ms", value / 1_000_000.0)
-    } else {
-        format!("{sign}{:.3}s", value / 1_000_000_000.0)
-    }
-}
-
-#[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"));
-    }
-
-    #[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-cli/src/cmd/tui/args.rs

@@ -1,303 +0,0 @@
-use std::time::Duration;
-
-use clap::Parser;
-use irtt_client::ClientConfig;
-
-#[cfg(test)]
-use crate::shared::client::TimestampArg;
-use crate::shared::client::{
-    parse_labelled_target, parse_test_duration, resolved_managed_targets, target_specs,
-    CommonClientArgs, GroupPacingArg, LabelledTargetArg, ResolvedTarget, TargetSpec,
-};
-
-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 or host, with optional port. Repeat for multi-target mode.
-    #[arg(
-        value_name = "TARGET",
-        num_args = 0..,
-        required_unless_present = "labelled_targets",
-        long_help = "Server address or host, with optional port. Repeat the positional target for multi-target mode, for example: irtt-tui host-a:2112 host-b:2112."
-    )]
-    pub targets: Vec<String>,
-
-    /// Explicit labelled target, as label=host:port. Repeat for multi-target mode.
-    #[arg(
-        long = "target",
-        value_name = "LABEL=TARGET",
-        value_parser = parse_labelled_target,
-        long_help = "Explicit labelled target, as label=host:port. Repeat for multi-target mode. The label is used in the legend and status table and must be unique."
-    )]
-    pub labelled_targets: Vec<LabelledTargetArg>,
-
-    /// Managed group pacing for multi-target mode.
-    #[arg(
-        long,
-        value_enum,
-        default_value_t = GroupPacingArg::Staggered,
-        long_help = "Managed group pacing for multi-target mode.\n\nstaggered spaces active targets across the probe interval. burst sends one probe to every active target back-to-back once per interval."
-    )]
-    pub pacing: GroupPacingArg,
-
-    #[arg(
-        long,
-        default_value = "0",
-        value_parser = parse_test_duration,
-        help = "Test duration; use 0 for continuous mode",
-        long_help = "Test duration; use 0 for continuous mode. The TUI defaults to continuous mode."
-    )]
-    pub duration: Duration,
-
-    #[command(flatten)]
-    pub common: CommonClientArgs,
-}
-
-impl TuiArgs {
-    pub fn to_client_config(&self) -> ClientConfig {
-        self.common.to_client_config(
-            self.primary_target_addr()
-                .expect("at least one target is required"),
-            self.duration,
-        )
-    }
-
-    pub fn is_continuous(&self) -> bool {
-        self.duration == Duration::ZERO
-    }
-
-    pub fn target_specs(&self) -> Result<Vec<TuiTargetSpec>, String> {
-        target_specs(&self.targets, &self.labelled_targets)
-    }
-
-    pub fn resolved_managed_targets(&self) -> Result<Vec<ResolvedTuiTarget>, String> {
-        let specs = self.target_specs()?;
-        let config = self.to_client_config();
-        resolved_managed_targets(specs, &config)
-    }
-
-    #[cfg(test)]
-    pub fn timestamp_mode(&self) -> TimestampArg {
-        self.common.tstamp
-    }
-
-    fn primary_target_addr(&self) -> Option<&str> {
-        self.targets.first().map(String::as_str).or_else(|| {
-            self.labelled_targets
-                .first()
-                .map(|target| target.addr.as_str())
-        })
-    }
-}
-
-pub type TuiTargetSpec = TargetSpec;
-pub type ResolvedTuiTarget = ResolvedTarget;
-
-impl std::ops::Deref for TuiArgs {
-    type Target = CommonClientArgs;
-
-    fn deref(&self) -> &Self::Target {
-        &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, ["127.0.0.1:2112"]);
-        assert!(args.labelled_targets.is_empty());
-        assert_eq!(args.pacing, GroupPacingArg::Staggered);
-        assert_eq!(args.duration, DEFAULT_TUI_DURATION);
-        assert!(args.is_continuous());
-        assert_eq!(args.to_client_config().duration, None);
-
-        let finite = parse(&["--duration", "30s", "127.0.0.1:2112"]).unwrap();
-        assert_eq!(finite.duration, Duration::from_secs(30));
-        assert_eq!(
-            finite.to_client_config().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.target_specs().unwrap();
-
-        assert_eq!(specs[0].label, "host-a:2112");
-        assert_eq!(specs[0].addr, "host-a:2112");
-        assert_eq!(specs[1].label, "host-b:2112");
-        assert_eq!(specs[1].addr, "host-b:2112");
-    }
-
-    #[test]
-    fn repeated_labelled_targets_parse() {
-        let args = parse(&[
-            "--target",
-            "ams=ams.example.com:2112",
-            "--target",
-            "sg=sg.example.com:2112",
-        ])
-        .unwrap();
-        let specs = args.target_specs().unwrap();
-
-        assert_eq!(specs[0].label, "ams");
-        assert_eq!(specs[0].addr, "ams.example.com:2112");
-        assert_eq!(specs[1].label, "sg");
-        assert_eq!(specs[1].addr, "sg.example.com:2112");
-    }
-
-    #[test]
-    fn at_least_one_target_is_required() {
-        assert!(parse(&[]).is_err());
-    }
-
-    #[test]
-    fn duplicate_labels_are_rejected() {
-        let args = parse(&["host-a:2112", "--target", "host-a:2112=host-b:2112"]).unwrap();
-        let err = args.target_specs().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.target_specs().unwrap();
-
-        assert_eq!(specs[0].label, "host-a:2112");
-        assert_eq!(specs[1].label, "host-a:2112#2");
-    }
-
-    #[test]
-    fn duplicate_resolved_target_addresses_are_rejected() {
-        let args = parse(&["127.0.0.1:2112", "127.0.0.1"]).unwrap();
-        let err = args.resolved_managed_targets().unwrap_err();
-
-        assert!(err.contains("duplicate resolved target address 127.0.0.1:2112"));
-    }
-
-    #[test]
-    fn invalid_labelled_target_syntax_is_rejected() {
-        assert!(parse(&["--target", "missing-equals"]).is_err());
-        assert!(parse(&["--target", "=127.0.0.1:2112"]).is_err());
-        assert!(parse(&["--target", "label="]).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().to_client_config();
-        let common = parse_shared(&shared).unwrap().common;
-        let shared = common.to_client_config("127.0.0.1:2112", Duration::from_secs(30));
-
-        assert_eq!(shared.server_addr, tui.server_addr);
-        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 tui_help_lists_multi_target_options() {
-        let help = TuiArgs::command().render_help().to_string();
-        assert!(help.contains("--target <LABEL=TARGET>"));
-        assert!(help.contains("--pacing <PACING>"));
-    }
-}

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

@@ -1,468 +0,0 @@
-use std::{
-    io,
-    sync::atomic::{AtomicBool, Ordering},
-    thread,
-    time::{Duration, Instant},
-};
-
-use crossterm::event::{self, Event, KeyCode, KeyEventKind, KeyModifiers};
-use irtt_client::{
-    ClientEvent, EventSubscriptionError, ManagedClientGroup, ManagedClientGroupConfig,
-    ManagedGroupEndReason, SubscriberConfig, SubscriberOverflow,
-};
-
-use crate::{
-    cmd::tui::args::{ResolvedTuiTarget, TuiArgs},
-    shared::client::{is_shutdown_requested, ClientSession},
-};
-
-use super::ui::{should_render, TuiConfig, TuiState, TuiStatus, TuiTerminal};
-
-const RENDER_INTERVAL: Duration = Duration::from_millis(250);
-const TUI_WAIT_SLICE: Duration = Duration::from_millis(20);
-const IDLE_SLEEP: Duration = Duration::from_millis(5);
-const GROUP_COMPLETION_GRACE: Duration = Duration::from_secs(1);
-
-pub fn run_tui(
-    args: TuiArgs,
-    shutdown_requested: &AtomicBool,
-) -> Result<(), Box<dyn std::error::Error>> {
-    let targets = args
-        .resolved_managed_targets()
-        .map_err(|err| io::Error::new(io::ErrorKind::InvalidInput, err))?;
-    let continuous = args.is_continuous();
-    let mut terminal = TuiTerminal::enter()?;
-    let mut state = TuiState::with_target_labels(
-        TuiConfig::from_args(&args),
-        targets.iter().map(|target| target.label.clone()),
-    );
-    let mut next_render = Instant::now();
-
-    if is_shutdown_requested(shutdown_requested) {
-        return Ok(());
-    }
-
-    state.set_status(TuiStatus::Opening);
-    render_if_due(&mut terminal, &state, &mut next_render, true)?;
-
-    if targets.len() > 1 {
-        return run_group_tui(
-            args,
-            targets,
-            &mut terminal,
-            &mut state,
-            &mut next_render,
-            shutdown_requested,
-        );
-    }
-
-    let mut session = match ClientSession::connect(args.to_client_config(), continuous) {
-        Ok(session) => session,
-        Err(err) => {
-            state.set_error(err.to_string());
-            render_if_due(&mut terminal, &state, &mut next_render, true)?;
-            return Err(Box::new(err));
-        }
-    };
-
-    if is_shutdown_requested(shutdown_requested) {
-        return Ok(());
-    }
-
-    let events = session.open()?;
-    state.process_events(&events);
-    render_if_due(&mut terminal, &state, &mut next_render, true)?;
-
-    let mut interrupted = false;
-    // Keep this in lockstep with run_stream: send due probes, drain available
-    // replies, poll timeouts, sleep toward the next absolute send deadline,
-    // then perform the same final drain, timeout poll, and close sequence.
-    while session.should_continue(shutdown_requested) {
-        if handle_input(&mut state, shutdown_requested)? {
-            render_if_due(&mut terminal, &state, &mut next_render, true)?;
-        }
-        if state.quit_requested {
-            interrupted = true;
-            break;
-        }
-
-        let events = session.step(shutdown_requested)?;
-        state.process_events(&events);
-
-        if is_shutdown_requested(shutdown_requested) {
-            interrupted = true;
-            break;
-        }
-
-        render_if_due(&mut terminal, &state, &mut next_render, false)?;
-        wait_for_tui_activity(
-            session.next_send_deadline(),
-            &mut next_render,
-            &mut state,
-            &mut terminal,
-            shutdown_requested,
-        )?;
-    }
-    interrupted |= is_shutdown_requested(shutdown_requested);
-
-    if interrupted {
-        state.set_status(TuiStatus::Interrupted);
-        render_if_due(&mut terminal, &state, &mut next_render, true)?;
-    }
-
-    if session.should_drain_final(interrupted) {
-        state.set_status(TuiStatus::Draining);
-        let mut drain_render = Instant::now();
-        session.drain_final(|events| {
-            state.process_events(events);
-            let _ = render_if_due(&mut terminal, &state, &mut drain_render, false);
-        })?;
-        render_if_due(&mut terminal, &state, &mut next_render, true)?;
-    }
-
-    let events = session.poll_timeouts()?;
-    state.process_events(&events);
-
-    state.set_status(TuiStatus::Closing);
-    render_if_due(&mut terminal, &state, &mut next_render, true)?;
-
-    let events = session.close()?;
-    state.process_events(&events);
-    state.set_status(TuiStatus::Complete);
-    render_if_due(&mut terminal, &state, &mut next_render, true)?;
-    Ok(())
-}
-
-fn run_group_tui(
-    args: TuiArgs,
-    targets: Vec<ResolvedTuiTarget>,
-    terminal: &mut TuiTerminal,
-    state: &mut TuiState,
-    next_render: &mut Instant,
-    shutdown_requested: &AtomicBool,
-) -> Result<(), Box<dyn std::error::Error>> {
-    let mut config = args.to_client_config();
-    let managed_targets = targets
-        .iter()
-        .map(|target| target.managed.clone())
-        .collect::<Vec<_>>();
-    let expected_target_count = managed_targets.len();
-    if let Some(first) = managed_targets.first() {
-        config.server_addr = first.remote.to_string();
-    }
-
-    let group_config = ManagedClientGroupConfig {
-        client: config,
-        pacing: args.pacing.into(),
-    };
-    let (session, events) = ManagedClientGroup::start_with_subscription(
-        group_config,
-        managed_targets,
-        SubscriberConfig {
-            capacity: 16_384,
-            overflow: SubscriberOverflow::DropOldest,
-        },
-    )?;
-
-    let mut interrupted = false;
-    let mut terminal_targets = std::collections::HashSet::new();
-    let mut saw_target_event = false;
-    let mut last_event_at = Instant::now();
-
-    let exit = loop {
-        if is_shutdown_requested(shutdown_requested) {
-            interrupted = true;
-            session.stop();
-        }
-
-        if handle_input(state, shutdown_requested)? {
-            render_if_due(terminal, state, next_render, true)?;
-        }
-        if state.quit_requested {
-            interrupted = true;
-            session.stop();
-        }
-
-        match events.try_recv() {
-            Ok(Some(target_event)) => {
-                saw_target_event = true;
-                last_event_at = Instant::now();
-                if is_terminal_target_event(&target_event.event) {
-                    terminal_targets.insert(target_event.target.as_str().to_owned());
-                }
-                state.process_target_event(&target_event);
-                render_if_due(terminal, state, next_render, false)?;
-            }
-            Ok(None) => {
-                if interrupted {
-                    break GroupLoopExit::Interrupted;
-                }
-                if terminal_targets.len() >= expected_target_count {
-                    break GroupLoopExit::AllTargetsTerminal;
-                }
-                if should_join_group_after_idle(&args, saw_target_event, last_event_at) {
-                    break GroupLoopExit::IdleGraceElapsed;
-                }
-                wait_for_tui_activity(None, next_render, state, terminal, shutdown_requested)?;
-                thread::sleep(IDLE_SLEEP);
-            }
-            Err(EventSubscriptionError::Disconnected) => {
-                break GroupLoopExit::SubscriptionDisconnected
-            }
-        }
-    };
-
-    if exit.should_stop_before_join() {
-        session.stop();
-    }
-
-    if interrupted {
-        state.set_status(TuiStatus::Interrupted);
-        render_if_due(terminal, state, next_render, true)?;
-    }
-
-    state.set_status(TuiStatus::Closing);
-    render_if_due(terminal, state, next_render, true)?;
-
-    let outcome = session.join()?;
-    while let Ok(Some(target_event)) = events.try_recv() {
-        state.process_target_event(&target_event);
-    }
-
-    if outcome.end_reason == ManagedGroupEndReason::Cancelled && !interrupted {
-        return match exit {
-            GroupLoopExit::IdleGraceElapsed => {
-                Err("managed client group stayed idle before all targets completed".into())
-            }
-            GroupLoopExit::SubscriptionDisconnected => {
-                Err("managed client group event subscription disconnected before completion".into())
-            }
-            GroupLoopExit::Interrupted | GroupLoopExit::AllTargetsTerminal => {
-                Err("managed client group was cancelled".into())
-            }
-        };
-    }
-
-    state.set_status(TuiStatus::Complete);
-    render_if_due(terminal, state, next_render, true)?;
-    Ok(())
-}
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-enum GroupLoopExit {
-    Interrupted,
-    AllTargetsTerminal,
-    IdleGraceElapsed,
-    SubscriptionDisconnected,
-}
-
-impl GroupLoopExit {
-    fn should_stop_before_join(self) -> bool {
-        matches!(
-            self,
-            Self::Interrupted | Self::IdleGraceElapsed | Self::SubscriptionDisconnected
-        )
-    }
-}
-
-fn is_terminal_target_event(event: &ClientEvent) -> bool {
-    matches!(
-        event,
-        ClientEvent::SessionClosed { .. } | ClientEvent::NoTestCompleted { .. }
-    )
-}
-
-fn estimated_group_completion_grace(args: &TuiArgs) -> Duration {
-    let open_timeout: Duration = args.to_client_config().open_timeouts.iter().sum();
-    open_timeout
-        .saturating_add(args.duration)
-        .saturating_add(GROUP_COMPLETION_GRACE)
-}
-
-fn should_join_group_after_idle(
-    args: &TuiArgs,
-    saw_target_event: bool,
-    last_event_at: Instant,
-) -> bool {
-    if args.is_continuous() && saw_target_event {
-        return false;
-    }
-    last_event_at.elapsed() > estimated_group_completion_grace(args)
-}
-
-fn handle_input(state: &mut TuiState, shutdown_requested: &AtomicBool) -> io::Result<bool> {
-    let mut force_render = false;
-    while event::poll(Duration::ZERO)? {
-        let Event::Key(key) = event::read()? else {
-            continue;
-        };
-        if key.kind == KeyEventKind::Release {
-            continue;
-        }
-        match key.code {
-            KeyCode::Char('q') => {
-                state.quit_requested = true;
-                shutdown_requested.store(true, Ordering::Relaxed);
-                force_render = true;
-            }
-            KeyCode::Char('c') if key.modifiers.contains(KeyModifiers::CONTROL) => {
-                state.quit_requested = true;
-                shutdown_requested.store(true, Ordering::Relaxed);
-                force_render = true;
-            }
-            KeyCode::Char('r') => {
-                state.clear_visible_history();
-                force_render = true;
-            }
-            KeyCode::Char('p') => {
-                state.toggle_pause();
-                force_render = true;
-            }
-            KeyCode::Char('g') => {
-                state.toggle_view();
-                force_render = true;
-            }
-            KeyCode::Char('m') => {
-                state.cycle_graph_metric();
-                force_render = true;
-            }
-            KeyCode::Left => {
-                state.pan_graph_left();
-                force_render = true;
-            }
-            KeyCode::Right => {
-                state.pan_graph_right();
-                force_render = true;
-            }
-            KeyCode::PageUp => {
-                state.pan_graph_page_left();
-                force_render = true;
-            }
-            KeyCode::PageDown => {
-                state.pan_graph_page_right();
-                force_render = true;
-            }
-            KeyCode::Home => {
-                state.jump_graph_oldest();
-                force_render = true;
-            }
-            KeyCode::End => {
-                state.jump_graph_live();
-                force_render = true;
-            }
-            KeyCode::Char('+') | KeyCode::Char('=') => {
-                state.zoom_graph_in();
-                force_render = true;
-            }
-            KeyCode::Char('-') => {
-                state.zoom_graph_out();
-                force_render = true;
-            }
-            KeyCode::Char('0') => {
-                state.reset_graph_window();
-                force_render = true;
-            }
-            _ => {}
-        }
-    }
-    Ok(force_render)
-}
-
-fn render_if_due(
-    terminal: &mut TuiTerminal,
-    state: &TuiState,
-    next_render: &mut Instant,
-    force: bool,
-) -> io::Result<()> {
-    let now = Instant::now();
-    if !should_render(now, *next_render, state.paused, force) {
-        return Ok(());
-    }
-    terminal.draw(state)?;
-    *next_render = now + RENDER_INTERVAL;
-    Ok(())
-}
-
-fn wait_for_tui_activity(
-    next_send_deadline: Option<Instant>,
-    next_render: &mut Instant,
-    state: &mut TuiState,
-    terminal: &mut TuiTerminal,
-    shutdown_requested: &AtomicBool,
-) -> io::Result<()> {
-    let wait_for = tui_wait_duration(next_send_deadline, *next_render, state.paused);
-    if wait_for.is_zero() || !event::poll(wait_for)? {
-        return Ok(());
-    }
-
-    if handle_input(state, shutdown_requested)? {
-        render_if_due(terminal, state, next_render, true)?;
-    }
-    Ok(())
-}
-
-fn tui_wait_duration(
-    next_send_deadline: Option<Instant>,
-    next_render: Instant,
-    paused: bool,
-) -> Duration {
-    let now = Instant::now();
-    let send_wait = next_send_deadline
-        .map(|deadline| deadline.saturating_duration_since(now))
-        .unwrap_or(IDLE_SLEEP);
-    let render_wait = if paused {
-        send_wait
-    } else {
-        next_render.saturating_duration_since(now)
-    };
-    send_wait.min(render_wait).min(TUI_WAIT_SLICE)
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use clap::Parser;
-
-    fn parse(args: &[&str]) -> TuiArgs {
-        let mut argv = vec!["irtt-tui"];
-        argv.extend_from_slice(args);
-        TuiArgs::try_parse_from(argv).unwrap()
-    }
-
-    #[test]
-    fn continuous_multi_target_idle_does_not_stop_after_events() {
-        let args = parse(&["127.0.0.1:2112", "127.0.0.2:2112"]);
-        let old_event_at = Instant::now() - estimated_group_completion_grace(&args) - IDLE_SLEEP;
-
-        assert!(!should_join_group_after_idle(&args, true, old_event_at));
-    }
-
-    #[test]
-    fn finite_or_unopened_group_can_leave_after_idle_grace() {
-        let finite = parse(&["--duration", "1s", "127.0.0.1:2112", "127.0.0.2:2112"]);
-        let finite_old_event_at =
-            Instant::now() - estimated_group_completion_grace(&finite) - IDLE_SLEEP;
-        assert!(should_join_group_after_idle(
-            &finite,
-            true,
-            finite_old_event_at
-        ));
-
-        let continuous = parse(&["127.0.0.1:2112", "127.0.0.2:2112"]);
-        let unopened_old_event_at =
-            Instant::now() - estimated_group_completion_grace(&continuous) - IDLE_SLEEP;
-        assert!(should_join_group_after_idle(
-            &continuous,
-            false,
-            unopened_old_event_at
-        ));
-    }
-
-    #[test]
-    fn protective_group_exits_stop_before_joining() {
-        assert!(GroupLoopExit::Interrupted.should_stop_before_join());
-        assert!(GroupLoopExit::IdleGraceElapsed.should_stop_before_join());
-        assert!(GroupLoopExit::SubscriptionDisconnected.should_stop_before_join());
-        assert!(!GroupLoopExit::AllTargetsTerminal.should_stop_before_join());
-    }
-}

crates/irtt-cli/src/entry.rs

@@ -1,80 +0,0 @@
-use std::{
-    env,
-    ffi::OsString,
-    process::ExitCode,
-    sync::{atomic::AtomicBool, Arc},
-};
-
-use crate::{
-    applet::{dispatch_from_argv, AppletDispatch, RequestedApplet},
-    signal::install_signal_handler,
-};
-
-pub fn main() -> ExitCode {
-    match run_from_env() {
-        Ok(()) => ExitCode::SUCCESS,
-        Err(err) => {
-            eprintln!("irtt-rs: {err}");
-            ExitCode::FAILURE
-        }
-    }
-}
-
-fn run_from_env() -> Result<(), Box<dyn std::error::Error>> {
-    let argv: Vec<OsString> = env::args_os().collect();
-    let (requested, argv) = match dispatch_from_argv(argv)? {
-        AppletDispatch::Run { applet, argv } => (applet, argv),
-        AppletDispatch::Help(help) => {
-            print!("{help}");
-            return Ok(());
-        }
-    };
-
-    let shutdown_requested = Arc::new(AtomicBool::new(false));
-    install_signal_handler(Arc::clone(&shutdown_requested))
-        .map_err(|err| format!("failed to install signal handler: {err}"))?;
-
-    match requested {
-        RequestedApplet::Client => run_client_applet(argv, shutdown_requested.as_ref()),
-        RequestedApplet::Tui => run_tui_applet(argv, shutdown_requested.as_ref()),
-        RequestedApplet::Server => Err("server applet is not available in this build".into()),
-    }
-}
-
-#[cfg(feature = "client")]
-fn run_client_applet(
-    argv: Vec<OsString>,
-    shutdown_requested: &AtomicBool,
-) -> Result<(), Box<dyn std::error::Error>> {
-    use clap::Parser;
-
-    let args = crate::cmd::client::ClientArgs::parse_from(argv);
-    crate::cmd::client::run_stream(args, shutdown_requested)
-}
-
-#[cfg(not(feature = "client"))]
-fn run_client_applet(
-    _argv: Vec<OsString>,
-    _shutdown_requested: &AtomicBool,
-) -> Result<(), Box<dyn std::error::Error>> {
-    Err("client applet is not available; rebuild with the client feature".into())
-}
-
-#[cfg(feature = "tui")]
-fn run_tui_applet(
-    argv: Vec<OsString>,
-    shutdown_requested: &AtomicBool,
-) -> Result<(), Box<dyn std::error::Error>> {
-    use clap::Parser;
-
-    let args = crate::cmd::tui::TuiArgs::parse_from(argv);
-    crate::cmd::tui::run_tui(args, shutdown_requested)
-}
-
-#[cfg(not(feature = "tui"))]
-fn run_tui_applet(
-    _argv: Vec<OsString>,
-    _shutdown_requested: &AtomicBool,
-) -> Result<(), Box<dyn std::error::Error>> {
-    Err("TUI applet is not available; rebuild with the tui feature".into())
-}

crates/irtt-cli/src/shared/client/config.rs

@@ -1,48 +0,0 @@
-use std::time::Duration;
-
-use irtt_client::{ClientConfig, NegotiationPolicy, SocketConfig};
-
-use super::args::CommonClientArgs;
-
-pub const DEFAULT_RECV_TIMEOUT: Duration = Duration::from_millis(20);
-
-impl CommonClientArgs {
-    pub fn to_client_config(&self, server: &str, duration: Duration) -> ClientConfig {
-        ClientConfig {
-            server_addr: server.to_owned(),
-            duration: (!duration.is_zero()).then_some(duration),
-            interval: self.interval,
-            length: self.length,
-            received_stats: self.stats.into(),
-            stamp_at: self.tstamp.into(),
-            clock: self.clock.into(),
-            dscp: self.dscp,
-            hmac_key: self.hmac.as_ref().map(|key| key.as_bytes().to_vec()),
-            server_fill: self.server_fill.clone(),
-            negotiation_policy: if self.loose {
-                NegotiationPolicy::Loose
-            } else {
-                NegotiationPolicy::Strict
-            },
-            socket_config: SocketConfig {
-                ttl: self.ttl,
-                recv_timeout: Some(DEFAULT_RECV_TIMEOUT),
-                ..SocketConfig::default()
-            },
-            ..ClientConfig::default()
-        }
-    }
-}
-
-pub fn expected_probe_count(duration: Duration, interval: Duration) -> u64 {
-    let interval_nanos = interval.as_nanos();
-    if interval_nanos == 0 {
-        return u64::MAX;
-    }
-
-    let expected = duration
-        .as_nanos()
-        .saturating_add(interval_nanos.saturating_sub(1))
-        / interval_nanos;
-    expected.min(u128::from(u64::MAX)) as u64
-}

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

@@ -1,15 +0,0 @@
-pub mod args;
-pub mod config;
-pub mod session;
-pub mod targets;
-
-pub use args::{
-    parse_dscp, parse_duration, parse_length, parse_server_fill, parse_test_duration, parse_ttl,
-    ClockArg, CommonClientArgs, ReceivedStatsArg, TimestampArg,
-};
-pub use config::{expected_probe_count, DEFAULT_RECV_TIMEOUT};
-pub use session::{final_drain_duration, is_shutdown_requested, ClientSession, RECV_BUDGET};
-pub use targets::{
-    parse_labelled_target, resolved_managed_targets, target_specs, GroupPacingArg,
-    LabelledTargetArg, ResolvedTarget, TargetSpec,
-};

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

@@ -1,370 +0,0 @@
-use std::{
-    sync::atomic::{AtomicBool, Ordering},
-    thread,
-    time::{Duration, Instant},
-};
-
-use irtt_client::{Client, ClientConfig, ClientEvent, OpenOutcome, RecvBudget};
-
-pub const RECV_BUDGET: RecvBudget = RecvBudget { max_packets: 16 };
-const MAX_FINAL_DRAIN: Duration = Duration::from_secs(30);
-const IDLE_SLEEP: Duration = Duration::from_millis(5);
-const MAX_SLEEP: Duration = Duration::from_millis(20);
-
-pub struct ClientSession {
-    client: Client,
-    continuous: bool,
-}
-
-impl ClientSession {
-    pub fn connect(
-        config: ClientConfig,
-        continuous: bool,
-    ) -> Result<Self, irtt_client::ClientError> {
-        Ok(Self {
-            client: Client::connect(config)?,
-            continuous,
-        })
-    }
-
-    pub fn open(&mut self) -> Result<Vec<ClientEvent>, irtt_client::ClientError> {
-        Ok(vec![open_event(&self.client.open()?).clone()])
-    }
-
-    pub fn step(
-        &mut self,
-        shutdown_requested: &AtomicBool,
-    ) -> Result<Vec<ClientEvent>, irtt_client::ClientError> {
-        let mut events = Vec::new();
-        if should_send_probe(self.client.next_send_deadline(), shutdown_requested) {
-            events.extend(self.client.send_probe()?);
-        }
-        events.extend(self.client.recv_available(RECV_BUDGET)?);
-        if self.client.is_peer_closed() {
-            return Ok(events);
-        }
-        events.extend(self.client.poll_timeouts()?);
-        Ok(events)
-    }
-
-    pub fn should_continue(&self, shutdown_requested: &AtomicBool) -> bool {
-        !is_shutdown_requested(shutdown_requested)
-            && !self.client.is_peer_closed()
-            && (self.continuous || self.client.next_send_deadline().is_some())
-    }
-
-    pub fn should_drain_final(&self, interrupted: bool) -> bool {
-        should_drain_final(self.continuous, interrupted)
-    }
-
-    pub fn drain_final<F>(&mut self, mut on_events: F) -> Result<(), irtt_client::ClientError>
-    where
-        F: FnMut(&[ClientEvent]),
-    {
-        let deadline = Instant::now() + final_drain_duration(self.client.probe_timeout());
-        loop {
-            if self.client.is_peer_closed() {
-                break;
-            }
-
-            let mut received = false;
-
-            let events = self.client.recv_available(RECV_BUDGET)?;
-            received |= !events.is_empty();
-            on_events(&events);
-
-            if self.client.is_peer_closed() {
-                break;
-            }
-
-            let events = self.client.poll_timeouts()?;
-            received |= !events.is_empty();
-            on_events(&events);
-
-            if self.client.is_run_complete() || Instant::now() >= deadline {
-                break;
-            }
-
-            if !received {
-                thread::sleep(IDLE_SLEEP);
-            }
-        }
-        Ok(())
-    }
-
-    pub fn poll_timeouts(&mut self) -> Result<Vec<ClientEvent>, irtt_client::ClientError> {
-        if self.client.is_peer_closed() {
-            return Ok(vec![]);
-        }
-        self.client.poll_timeouts()
-    }
-
-    pub fn close(&mut self) -> Result<Vec<ClientEvent>, irtt_client::ClientError> {
-        if self.client.is_peer_closed() {
-            return Ok(vec![]);
-        }
-        self.client.close()
-    }
-
-    pub fn next_send_deadline(&self) -> Option<Instant> {
-        self.client.next_send_deadline()
-    }
-
-    pub fn probe_timeout(&self) -> Duration {
-        self.client.probe_timeout()
-    }
-
-    pub fn sleep_until_next_send(&self) {
-        let sleep_for = match self.next_send_deadline() {
-            Some(deadline) => deadline
-                .saturating_duration_since(Instant::now())
-                .min(MAX_SLEEP),
-            None => Duration::from_millis(1),
-        };
-        if !sleep_for.is_zero() {
-            thread::sleep(sleep_for);
-        }
-    }
-}
-
-pub fn is_shutdown_requested(shutdown_requested: &AtomicBool) -> bool {
-    shutdown_requested.load(Ordering::Relaxed)
-}
-
-pub fn should_drain_final(continuous: bool, interrupted: bool) -> bool {
-    !continuous || interrupted
-}
-
-pub fn should_print_final_summary(continuous: bool, interrupted: bool) -> bool {
-    !continuous || interrupted
-}
-
-pub fn final_drain_duration(probe_timeout: Duration) -> Duration {
-    probe_timeout.min(MAX_FINAL_DRAIN)
-}
-
-fn should_send_probe(next_send_deadline: Option<Instant>, shutdown_requested: &AtomicBool) -> bool {
-    !is_shutdown_requested(shutdown_requested)
-        && next_send_deadline.is_some_and(|deadline| deadline <= Instant::now())
-}
-
-fn open_event(outcome: &OpenOutcome) -> &ClientEvent {
-    match outcome {
-        OpenOutcome::Started { event, .. } | OpenOutcome::NoTestCompleted { event, .. } => event,
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use irtt_proto::{
-        echo_packet_len,
-        flags::{self, FLAG_OPEN, FLAG_REPLY},
-        layout::PacketLayout,
-        Clock, Params, ReceivedStats, StampAt, TimestampFields, MAGIC, PROTOCOL_VERSION,
-    };
-    use std::{
-        net::{SocketAddr, UdpSocket},
-        thread::JoinHandle,
-    };
-
-    const TOKEN: u64 = 0x1234_5678_90ab_cdef;
-
-    struct FakeServer {
-        addr: SocketAddr,
-        done: JoinHandle<()>,
-    }
-
-    impl FakeServer {
-        fn join(self) {
-            self.done.join().unwrap();
-        }
-    }
-
-    #[test]
-    fn final_drain_uses_capped_probe_timeout() {
-        assert_eq!(
-            final_drain_duration(Duration::from_secs(4)),
-            Duration::from_secs(4)
-        );
-        assert_eq!(
-            final_drain_duration(Duration::from_secs(60)),
-            Duration::from_secs(30)
-        );
-    }
-
-    #[test]
-    fn should_drain_final_for_finite_or_interrupted_runs() {
-        assert!(should_drain_final(false, false));
-        assert!(should_drain_final(false, true));
-        assert!(should_drain_final(true, true));
-        assert!(!should_drain_final(true, false));
-    }
-
-    #[test]
-    fn peer_close_followed_by_session_cleanup_is_successful() {
-        let params = test_params(None, Duration::from_millis(10));
-        let server = start_peer_close_server(params);
-        let mut session = ClientSession::connect(config(server.addr, None), true).unwrap();
-        let shutdown_requested = AtomicBool::new(false);
-
-        assert!(matches!(
-            session.open().unwrap().as_slice(),
-            [ClientEvent::SessionStarted { .. }]
-        ));
-
-        let events = session.step(&shutdown_requested).unwrap();
-        assert!(events
-            .iter()
-            .any(|event| matches!(event, ClientEvent::EchoReply { .. })));
-        assert!(events
-            .iter()
-            .any(|event| matches!(event, ClientEvent::SessionClosed { .. })));
-        assert!(!session.should_continue(&shutdown_requested));
-
-        session.drain_final(|_| {}).unwrap();
-        assert!(session.poll_timeouts().unwrap().is_empty());
-        assert!(session.close().unwrap().is_empty());
-        server.join();
-    }
-
-    fn config(addr: SocketAddr, duration: Option<Duration>) -> ClientConfig {
-        ClientConfig {
-            server_addr: addr.to_string(),
-            duration,
-            interval: Duration::from_millis(10),
-            open_timeouts: vec![Duration::from_millis(200)],
-            probe_timeout: Duration::from_millis(20),
-            socket_config: irtt_client::SocketConfig {
-                recv_timeout: Some(Duration::from_millis(200)),
-                ..Default::default()
-            },
-            ..ClientConfig::default()
-        }
-    }
-
-    fn test_params(duration: Option<Duration>, interval: Duration) -> Params {
-        Params {
-            protocol_version: PROTOCOL_VERSION,
-            duration_ns: duration.map_or(0, test_duration_ns_i64),
-            interval_ns: test_duration_ns_i64(interval),
-            length: 0,
-            received_stats: ReceivedStats::Both,
-            stamp_at: StampAt::Both,
-            clock: Clock::Both,
-            dscp: 0,
-            server_fill: None,
-        }
-    }
-
-    fn test_duration_ns_i64(duration: Duration) -> i64 {
-        i64::try_from(duration.as_nanos()).expect("test duration fits i64 nanoseconds")
-    }
-
-    fn start_peer_close_server(params: Params) -> FakeServer {
-        let socket = UdpSocket::bind("127.0.0.1:0").unwrap();
-        let addr = socket.local_addr().unwrap();
-        let done = thread::spawn(move || {
-            let (_, peer) = recv_request(&socket);
-            socket
-                .send_to(&open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params), peer)
-                .unwrap();
-
-            let (packet, peer) = recv_request(&socket);
-            let seq = u32::from_le_bytes(packet[12..16].try_into().unwrap());
-            socket
-                .send_to(
-                    &echo_reply_packet(
-                        TOKEN,
-                        seq,
-                        &params,
-                        &TimestampFields::default(),
-                        FLAG_REPLY | flags::FLAG_CLOSE,
-                    ),
-                    peer,
-                )
-                .unwrap();
-
-            socket
-                .set_read_timeout(Some(Duration::from_millis(250)))
-                .unwrap();
-            if let Some((packet, _)) = recv_request_timeout(&socket) {
-                panic!(
-                    "session cleanup must not send any packet after peer close; flags={:?} len={}",
-                    packet.get(3).copied(),
-                    packet.len()
-                );
-            }
-        });
-        FakeServer { addr, done }
-    }
-
-    fn recv_request(socket: &UdpSocket) -> (Vec<u8>, SocketAddr) {
-        let mut buf = [0_u8; 2048];
-        let (size, peer) = socket.recv_from(&mut buf).unwrap();
-        (buf[..size].to_vec(), peer)
-    }
-
-    fn recv_request_timeout(socket: &UdpSocket) -> Option<(Vec<u8>, SocketAddr)> {
-        let mut buf = [0_u8; 2048];
-        socket
-            .recv_from(&mut buf)
-            .ok()
-            .map(|(size, peer)| (buf[..size].to_vec(), peer))
-    }
-
-    fn open_reply(flags: u8, token: u64, params: &Params) -> Vec<u8> {
-        let mut packet = Vec::new();
-        packet.extend_from_slice(&MAGIC);
-        packet.push(flags);
-        packet.extend_from_slice(&token.to_le_bytes());
-        packet.extend_from_slice(&params.encode());
-        packet
-    }
-
-    fn echo_reply_packet(
-        token: u64,
-        seq: u32,
-        params: &Params,
-        timestamps: &TimestampFields,
-        flags: u8,
-    ) -> Vec<u8> {
-        let layout = PacketLayout::echo(false, params);
-        let packet_len = echo_packet_len(false, params)
-            .expect("session test params must have a non-negative packet length");
-        let mut packet = Vec::with_capacity(packet_len);
-
-        packet.extend_from_slice(&MAGIC);
-        packet.push(flags);
-        packet.extend_from_slice(&token.to_le_bytes());
-        packet.extend_from_slice(&seq.to_le_bytes());
-
-        if layout.recv_count {
-            packet.extend_from_slice(&42_u32.to_le_bytes());
-        }
-        if layout.recv_window {
-            packet.extend_from_slice(&0_u64.to_le_bytes());
-        }
-        if layout.recv_wall {
-            packet.extend_from_slice(&timestamps.recv_wall.unwrap_or(0).to_le_bytes());
-        }
-        if layout.recv_mono {
-            packet.extend_from_slice(&timestamps.recv_mono.unwrap_or(0).to_le_bytes());
-        }
-        if layout.midpoint_wall {
-            packet.extend_from_slice(&timestamps.midpoint_wall.unwrap_or(0).to_le_bytes());
-        }
-        if layout.midpoint_mono {
-            packet.extend_from_slice(&timestamps.midpoint_mono.unwrap_or(0).to_le_bytes());
-        }
-        if layout.send_wall {
-            packet.extend_from_slice(&timestamps.send_wall.unwrap_or(0).to_le_bytes());
-        }
-        if layout.send_mono {
-            packet.extend_from_slice(&timestamps.send_mono.unwrap_or(0).to_le_bytes());
-        }
-
-        packet.resize(packet_len, 0);
-        packet
-    }
-}

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

@@ -1,240 +0,0 @@
-use std::{collections::HashSet, net::ToSocketAddrs};
-
-use clap::ValueEnum;
-use irtt_client::{ClientConfig, ManagedGroupPacing, ManagedTargetConfig, TargetId};
-
-#[derive(Debug, Clone, PartialEq, Eq)]
-pub struct LabelledTargetArg {
-    pub label: String,
-    pub addr: String,
-}
-
-#[derive(Debug, Clone, PartialEq, Eq)]
-pub struct TargetSpec {
-    pub label: String,
-    pub addr: String,
-}
-
-#[derive(Debug, Clone)]
-pub struct ResolvedTarget {
-    pub label: String,
-    pub managed: ManagedTargetConfig,
-}
-
-#[derive(Debug, Clone, Copy, PartialEq, Eq, ValueEnum)]
-pub enum GroupPacingArg {
-    Staggered,
-    Burst,
-}
-
-impl From<GroupPacingArg> for ManagedGroupPacing {
-    fn from(value: GroupPacingArg) -> Self {
-        match value {
-            GroupPacingArg::Staggered => Self::Staggered,
-            GroupPacingArg::Burst => Self::Burst,
-        }
-    }
-}
-
-pub fn parse_labelled_target(input: &str) -> Result<LabelledTargetArg, String> {
-    let (label, addr) = input
-        .split_once('=')
-        .ok_or_else(|| "target must use LABEL=TARGET syntax".to_owned())?;
-    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(LabelledTargetArg {
-        label: label.to_owned(),
-        addr: addr.to_owned(),
-    })
-}
-
-pub fn target_specs(
-    positional_targets: &[String],
-    labelled_targets: &[LabelledTargetArg],
-) -> Result<Vec<TargetSpec>, String> {
-    let mut specs = Vec::new();
-    let mut positional_counts = std::collections::HashMap::<&str, usize>::new();
-    for target in positional_targets {
-        let count = positional_counts.entry(target.as_str()).or_default();
-        *count += 1;
-        let label = if *count == 1 {
-            target.clone()
-        } else {
-            format!("{target}#{}", *count)
-        };
-        specs.push(TargetSpec {
-            label,
-            addr: target.clone(),
-        });
-    }
-
-    for target in labelled_targets {
-        specs.push(TargetSpec {
-            label: target.label.clone(),
-            addr: target.addr.clone(),
-        });
-    }
-
-    if specs.is_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));
-        }
-    }
-
-    Ok(specs)
-}
-
-pub fn resolved_managed_targets(
-    specs: Vec<TargetSpec>,
-    config: &ClientConfig,
-) -> Result<Vec<ResolvedTarget>, String> {
-    let mut remotes = HashSet::new();
-    let mut targets = Vec::with_capacity(specs.len());
-    for spec in specs {
-        let remote = resolve_target(&spec.addr, config).map_err(|err| {
-            format!(
-                "failed to resolve target {} ({:?}): {err}",
-                spec.label, spec.addr
-            )
-        })?;
-        if !remotes.insert(remote) {
-            return Err(format!(
-                "duplicate resolved target address {remote} for label {}",
-                spec.label
-            ));
-        }
-        targets.push(ResolvedTarget {
-            label: spec.label.clone(),
-            managed: ManagedTargetConfig {
-                id: TargetId::from(spec.label),
-                remote,
-                auth: None,
-            },
-        });
-    }
-    Ok(targets)
-}
-
-pub fn resolve_target(addr: &str, config: &ClientConfig) -> Result<std::net::SocketAddr, String> {
-    let normalized = normalize_target_addr(addr);
-    let mut addrs = normalized
-        .to_socket_addrs()
-        .map_err(|_| format!("failed to resolve address {normalized:?}"))?;
-    addrs
-        .find(|addr| {
-            (!config.socket_config.ipv4_only || addr.is_ipv4())
-                && (!config.socket_config.ipv6_only || addr.is_ipv6())
-        })
-        .ok_or_else(|| format!("failed to resolve address {normalized:?}"))
-}
-
-pub fn normalize_target_addr(addr: &str) -> String {
-    const DEFAULT_PORT: u16 = 2112;
-    if addr.parse::<std::net::SocketAddr>().is_ok() {
-        return addr.to_owned();
-    }
-    if addr.starts_with('[') && addr.ends_with(']') {
-        return format!("{addr}:{DEFAULT_PORT}");
-    }
-    if addr.starts_with('[') {
-        return addr.to_owned();
-    }
-    if addr.parse::<std::net::Ipv6Addr>().is_ok() {
-        return format!("[{addr}]:{DEFAULT_PORT}");
-    }
-    if addr
-        .rsplit_once(':')
-        .is_some_and(|(_, port)| port.parse::<u16>().is_ok())
-    {
-        return addr.to_owned();
-    }
-    format!("{addr}:{DEFAULT_PORT}")
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn target_normalization_matches_single_target_forms() {
-        assert_eq!(normalize_target_addr("127.0.0.1"), "127.0.0.1:2112");
-        assert_eq!(normalize_target_addr("127.0.0.1:1234"), "127.0.0.1:1234");
-        assert_eq!(normalize_target_addr("example.com"), "example.com:2112");
-        assert_eq!(
-            normalize_target_addr("example.com:1234"),
-            "example.com:1234"
-        );
-        assert_eq!(normalize_target_addr("[::1]"), "[::1]:2112");
-        assert_eq!(normalize_target_addr("[::1]:1234"), "[::1]:1234");
-        assert_eq!(normalize_target_addr("::1"), "[::1]:2112");
-    }
-
-    #[test]
-    fn target_resolution_respects_family_filters() {
-        let config = ClientConfig::default();
-        assert_eq!(
-            resolve_target("127.0.0.1", &config).unwrap(),
-            "127.0.0.1:2112".parse().unwrap()
-        );
-        assert_eq!(
-            resolve_target("[::1]", &config).unwrap(),
-            "[::1]:2112".parse().unwrap()
-        );
-        assert_eq!(
-            resolve_target("::1", &config).unwrap(),
-            "[::1]:2112".parse().unwrap()
-        );
-
-        let mut ipv4_only = ClientConfig::default();
-        ipv4_only.socket_config.ipv4_only = true;
-        assert!(resolve_target("127.0.0.1", &ipv4_only).unwrap().is_ipv4());
-        assert!(resolve_target("::1", &ipv4_only).is_err());
-
-        let mut ipv6_only = ClientConfig::default();
-        ipv6_only.socket_config.ipv6_only = true;
-        assert!(resolve_target("::1", &ipv6_only).unwrap().is_ipv6());
-        assert!(resolve_target("127.0.0.1", &ipv6_only).is_err());
-    }
-
-    #[test]
-    fn target_specs_suffix_repeated_positionals_and_reject_duplicate_labels() {
-        let positionals = vec!["host-a:2112".to_owned(), "host-a:2112".to_owned()];
-        let specs = target_specs(&positionals, &[]).unwrap();
-
-        assert_eq!(specs[0].label, "host-a:2112");
-        assert_eq!(specs[1].label, "host-a:2112#2");
-
-        let labels = vec![LabelledTargetArg {
-            label: "host-a:2112".to_owned(),
-            addr: "host-b:2112".to_owned(),
-        }];
-        let err = target_specs(&positionals[..1], &labels).unwrap_err();
-        assert!(err.contains("duplicate target label"));
-    }
-
-    #[test]
-    fn duplicate_resolved_target_addresses_are_rejected() {
-        let specs = vec![
-            TargetSpec {
-                label: "a".to_owned(),
-                addr: "127.0.0.1:2112".to_owned(),
-            },
-            TargetSpec {
-                label: "b".to_owned(),
-                addr: "127.0.0.1".to_owned(),
-            },
-        ];
-        let err = resolved_managed_targets(specs, &ClientConfig::default()).unwrap_err();
-
-        assert!(err.contains("duplicate resolved target address 127.0.0.1:2112"));
-    }
-}

crates/irtt-cli/src/shared/mod.rs

@@ -1,2 +0,0 @@
-#[cfg(feature = "client-runtime")]
-pub mod client;

crates/irtt-cli/src/signal.rs

@@ -1,10 +0,0 @@
-use std::sync::{
-    atomic::{AtomicBool, Ordering},
-    Arc,
-};
-
-pub fn install_signal_handler(shutdown_requested: Arc<AtomicBool>) -> Result<(), ctrlc::Error> {
-    ctrlc::set_handler(move || {
-        shutdown_requested.store(true, Ordering::Relaxed);
-    })
-}

crates/irtt-cli/tests/applet_dispatch.rs

@@ -1,155 +0,0 @@
-use std::process::{Command, Output};
-
-fn irtt_rs() -> Command {
-    Command::new(env!("CARGO_BIN_EXE_irtt-rs"))
-}
-
-#[cfg(unix)]
-fn irtt_rs_with_arg0(arg0: &str) -> Command {
-    use std::os::unix::process::CommandExt;
-
-    let mut command = irtt_rs();
-    command.arg0(arg0);
-    command
-}
-
-fn output_text(output: &Output) -> String {
-    let mut text = String::new();
-    text.push_str(&String::from_utf8_lossy(&output.stdout));
-    text.push_str(&String::from_utf8_lossy(&output.stderr));
-    text
-}
-
-#[test]
-fn canonical_help_shows_dispatcher_help() {
-    let output = irtt_rs().arg("--help").output().unwrap();
-    let text = output_text(&output);
-
-    assert!(output.status.success(), "{text}");
-    assert!(text.contains("IRTT-compatible multi-applet dispatcher"));
-    assert!(text.contains("client"));
-    assert!(text.contains("tui"));
-    assert!(text.contains("server"));
-}
-
-#[test]
-fn canonical_without_applet_errors() {
-    let output = irtt_rs().output().unwrap();
-    let text = output_text(&output);
-
-    assert!(!output.status.success());
-    assert!(text.contains("choose an applet"), "{text}");
-    assert!(text.contains("client"));
-    assert!(text.contains("tui"));
-    assert!(text.contains("server"));
-}
-
-#[cfg(feature = "client")]
-#[test]
-fn canonical_client_subcommand_dispatches_to_client() {
-    let output = irtt_rs().args(["client", "--help"]).output().unwrap();
-    let text = output_text(&output);
-
-    assert!(output.status.success(), "{text}");
-    assert!(text.contains("Minimal IRTT-compatible stream client"));
-    assert!(text.contains("--format <FORMAT>"));
-    assert!(text.contains("--columns <COLUMNS>"));
-}
-
-#[cfg(not(feature = "client"))]
-#[test]
-fn canonical_client_subcommand_reports_unavailable_when_disabled() {
-    let output = irtt_rs().args(["client", "--help"]).output().unwrap();
-    let text = output_text(&output);
-
-    assert!(!output.status.success());
-    assert!(
-        text.contains("client applet is not available; rebuild with the client feature"),
-        "{text}"
-    );
-}
-
-#[cfg(unix)]
-#[cfg(feature = "client")]
-#[test]
-fn client_applet_name_dispatches_to_client() {
-    let output = irtt_rs_with_arg0("irtt-cli")
-        .arg("--help")
-        .output()
-        .unwrap();
-    let text = output_text(&output);
-
-    assert!(output.status.success(), "{text}");
-    assert!(text.contains("Minimal IRTT-compatible stream client"));
-    assert!(text.contains("--format <FORMAT>"));
-    assert!(text.contains("--columns <COLUMNS>"));
-}
-
-#[cfg(all(unix, not(feature = "client")))]
-#[test]
-fn client_applet_name_reports_unavailable_when_disabled() {
-    let output = irtt_rs_with_arg0("irtt-cli")
-        .arg("--help")
-        .output()
-        .unwrap();
-    let text = output_text(&output);
-
-    assert!(!output.status.success());
-    assert!(
-        text.contains("client applet is not available; rebuild with the client feature"),
-        "{text}"
-    );
-}
-
-#[cfg(all(unix, feature = "tui"))]
-#[test]
-fn tui_applet_name_dispatches_to_tui_when_enabled() {
-    let output = irtt_rs_with_arg0("irtt-tui")
-        .arg("--help")
-        .output()
-        .unwrap();
-    let text = output_text(&output);
-
-    assert!(output.status.success(), "{text}");
-    assert!(text.contains("Minimal IRTT-compatible TUI client"));
-    assert!(text.contains("--duration <DURATION>"));
-}
-
-#[cfg(all(unix, not(feature = "tui")))]
-#[test]
-fn tui_applet_name_reports_unavailable_when_disabled() {
-    let output = irtt_rs_with_arg0("irtt-tui")
-        .arg("--help")
-        .output()
-        .unwrap();
-    let text = output_text(&output);
-
-    assert!(!output.status.success());
-    assert!(text.contains("TUI applet is not available"), "{text}");
-}
-
-#[cfg(unix)]
-#[test]
-fn server_applet_name_reports_unavailable() {
-    let output = irtt_rs_with_arg0("irtt-server")
-        .arg("--help")
-        .output()
-        .unwrap();
-    let text = output_text(&output);
-
-    assert!(!output.status.success());
-    assert!(text.contains("server applet is not available"), "{text}");
-}
-
-#[cfg(unix)]
-#[test]
-fn unknown_irtt_applet_name_errors() {
-    let output = irtt_rs_with_arg0("irtt-typo").output().unwrap();
-    let text = output_text(&output);
-
-    assert!(!output.status.success());
-    assert!(text.contains("unknown applet name 'irtt-typo'"), "{text}");
-    assert!(text.contains("irtt-cli"));
-    assert!(text.contains("irtt-tui"));
-    assert!(text.contains("irtt-server"));
-}

crates/irtt-cli/tests/client_multi_target.rs

@@ -1,284 +0,0 @@
-#![cfg(feature = "client")]
-
-use std::{
-    net::{SocketAddr, UdpSocket},
-    process::Command,
-    thread,
-    thread::JoinHandle,
-    time::Duration,
-};
-
-use irtt_proto::{
-    echo_packet_len,
-    flags::{FLAG_CLOSE, FLAG_OPEN, FLAG_REPLY},
-    layout::PacketLayout,
-    Clock, Params, ReceivedStats, StampAt, TimestampFields, MAGIC, PROTOCOL_VERSION,
-};
-
-const TOKEN: u64 = 0x1234_5678_90ab_cdef;
-
-struct FakeServer {
-    addr: SocketAddr,
-    done: JoinHandle<()>,
-}
-
-impl FakeServer {
-    fn join(self) {
-        self.done.join().unwrap();
-    }
-}
-
-#[test]
-fn list_columns_succeeds_without_target() {
-    let output = Command::new(env!("CARGO_BIN_EXE_irtt-cli"))
-        .arg("--list-columns")
-        .output()
-        .unwrap();
-
-    assert!(
-        output.status.success(),
-        "status={:?}\nstderr={}",
-        output.status.code(),
-        String::from_utf8_lossy(&output.stderr)
-    );
-    let stdout = String::from_utf8(output.stdout).unwrap();
-    assert!(stdout.contains("Available event columns:"), "{stdout}");
-    assert!(stdout.contains("target"), "{stdout}");
-}
-
-#[test]
-fn single_target_default_table_omits_target_and_accepts_pacing() {
-    let server = start_echo_server(test_params(
-        Some(Duration::from_millis(30)),
-        Duration::from_millis(10),
-    ));
-
-    let output = Command::new(env!("CARGO_BIN_EXE_irtt-cli"))
-        .args([
-            "--duration",
-            "30ms",
-            "--interval",
-            "10ms",
-            "--pacing",
-            "burst",
-            "--header",
-            "always",
-            &server.addr.to_string(),
-        ])
-        .output()
-        .unwrap();
-
-    server.join();
-
-    assert!(
-        output.status.success(),
-        "status={:?}\nstderr={}",
-        output.status.code(),
-        String::from_utf8_lossy(&output.stderr)
-    );
-    let stdout = String::from_utf8(output.stdout).unwrap();
-    let header = stdout.lines().next().unwrap_or_default();
-    assert!(!header.split_whitespace().any(|column| column == "target"));
-}
-
-#[test]
-fn single_target_custom_target_column_renders_positional_label() {
-    let server = start_echo_server(test_params(
-        Some(Duration::from_millis(30)),
-        Duration::from_millis(10),
-    ));
-    let target = server.addr.to_string();
-
-    let output = Command::new(env!("CARGO_BIN_EXE_irtt-cli"))
-        .args([
-            "--duration",
-            "30ms",
-            "--interval",
-            "10ms",
-            "--format",
-            "csv",
-            "--columns",
-            "target,seq",
-            "--header",
-            "never",
-            &target,
-        ])
-        .output()
-        .unwrap();
-
-    server.join();
-
-    assert!(
-        output.status.success(),
-        "status={:?}\nstderr={}",
-        output.status.code(),
-        String::from_utf8_lossy(&output.stderr)
-    );
-    let stdout = String::from_utf8(output.stdout).unwrap();
-    assert!(
-        stdout
-            .lines()
-            .any(|line| line.starts_with(&format!("{target},"))),
-        "{stdout}"
-    );
-}
-
-#[test]
-fn multi_target_csv_emits_rows_for_both_labels() {
-    let params = test_params(Some(Duration::from_millis(40)), Duration::from_millis(10));
-    let a = start_echo_server(params.clone());
-    let b = start_echo_server(params);
-
-    let output = Command::new(env!("CARGO_BIN_EXE_irtt-cli"))
-        .args([
-            "--duration",
-            "40ms",
-            "--interval",
-            "10ms",
-            "--format",
-            "csv",
-            "--columns",
-            "target,seq,effective_rtt_us",
-            "--header",
-            "never",
-            "--target",
-            &format!("a={}", a.addr),
-            "--target",
-            &format!("b={}", b.addr),
-        ])
-        .output()
-        .unwrap();
-
-    a.join();
-    b.join();
-
-    assert!(
-        output.status.success(),
-        "status={:?}\nstderr={}",
-        output.status.code(),
-        String::from_utf8_lossy(&output.stderr)
-    );
-    let stdout = String::from_utf8(output.stdout).unwrap();
-    assert!(
-        stdout.lines().any(|line| line.starts_with("a,")),
-        "{stdout}"
-    );
-    assert!(
-        stdout.lines().any(|line| line.starts_with("b,")),
-        "{stdout}"
-    );
-}
-
-fn start_echo_server(params: Params) -> FakeServer {
-    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 done = thread::spawn(move || {
-        let (_, peer) = recv_request(&socket);
-        socket
-            .send_to(&open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &params), peer)
-            .unwrap();
-
-        loop {
-            let (packet, peer) = recv_request(&socket);
-            let flags = packet[3];
-            if flags & FLAG_CLOSE != 0 {
-                break;
-            }
-            let seq = u32::from_le_bytes(packet[12..16].try_into().unwrap());
-            socket
-                .send_to(
-                    &echo_reply_packet(
-                        TOKEN,
-                        seq,
-                        &params,
-                        &TimestampFields::default(),
-                        FLAG_REPLY,
-                    ),
-                    peer,
-                )
-                .unwrap();
-        }
-    });
-    FakeServer { addr, done }
-}
-
-fn recv_request(socket: &UdpSocket) -> (Vec<u8>, SocketAddr) {
-    let mut buf = [0_u8; 2048];
-    let (size, peer) = socket.recv_from(&mut buf).unwrap();
-    (buf[..size].to_vec(), peer)
-}
-
-fn open_reply(flags: u8, token: u64, params: &Params) -> Vec<u8> {
-    let mut packet = Vec::new();
-    packet.extend_from_slice(&MAGIC);
-    packet.push(flags);
-    packet.extend_from_slice(&token.to_le_bytes());
-    packet.extend_from_slice(&params.encode());
-    packet
-}
-
-fn echo_reply_packet(
-    token: u64,
-    seq: u32,
-    params: &Params,
-    timestamps: &TimestampFields,
-    flags: u8,
-) -> Vec<u8> {
-    let layout = PacketLayout::echo(false, params);
-    let packet_len = echo_packet_len(false, params).unwrap();
-    let mut packet = Vec::with_capacity(packet_len);
-
-    packet.extend_from_slice(&MAGIC);
-    packet.push(flags);
-    packet.extend_from_slice(&token.to_le_bytes());
-    packet.extend_from_slice(&seq.to_le_bytes());
-
-    if layout.recv_count {
-        packet.extend_from_slice(&42_u32.to_le_bytes());
-    }
-    if layout.recv_window {
-        packet.extend_from_slice(&0_u64.to_le_bytes());
-    }
-    if layout.recv_wall {
-        packet.extend_from_slice(&timestamps.recv_wall.unwrap_or(0).to_le_bytes());
-    }
-    if layout.recv_mono {
-        packet.extend_from_slice(&timestamps.recv_mono.unwrap_or(0).to_le_bytes());
-    }
-    if layout.midpoint_wall {
-        packet.extend_from_slice(&timestamps.midpoint_wall.unwrap_or(0).to_le_bytes());
-    }
-    if layout.midpoint_mono {
-        packet.extend_from_slice(&timestamps.midpoint_mono.unwrap_or(0).to_le_bytes());
-    }
-    if layout.send_wall {
-        packet.extend_from_slice(&timestamps.send_wall.unwrap_or(0).to_le_bytes());
-    }
-    if layout.send_mono {
-        packet.extend_from_slice(&timestamps.send_mono.unwrap_or(0).to_le_bytes());
-    }
-
-    packet.resize(packet_len, 0);
-    packet
-}
-
-fn test_params(duration: Option<Duration>, interval: Duration) -> Params {
-    Params {
-        protocol_version: PROTOCOL_VERSION,
-        duration_ns: duration.map_or(0, duration_ns_i64),
-        interval_ns: duration_ns_i64(interval),
-        length: 0,
-        received_stats: ReceivedStats::Both,
-        stamp_at: StampAt::Both,
-        clock: Clock::Both,
-        dscp: 0,
-        server_fill: None,
-    }
-}
-
-fn duration_ns_i64(duration: Duration) -> i64 {
-    i64::try_from(duration.as_nanos()).unwrap()
-}

crates/irtt-client/AGENTS.md

@@ -0,0 +1,232 @@
+# `irtt-client` guidance
+
+Repository-wide guidance in the root `AGENTS.md` also applies here.
+
+## Probe-send commitment API
+
+`Client::send_probe` and `AsyncClient::send_probe` return
+`Result<SendReceipt, SendProbeError>`; the Tokio poll driver returns the same
+result inside `Poll`. A receipt represents an Echo datagram accepted by the
+socket and already committed in session state: sequence and sent count advanced,
+and the probe entered pending tracking. It contains `seq`, `remote`, the public
+post-send `sent_at`, accepted `bytes`, and `send_call`, without schedule metadata.
+`ClientEvent::from(receipt)` constructs `EchoSent` with no schedule annotations.
+
+Classify every failure explicitly: `NotCommitted(ClientError)` means no datagram
+was accepted and no probe committed; `AfterCommit { receipt, source }` preserves
+the authoritative accepted send when length validation or TX error-queue
+processing fails. There is no blanket `From<ClientError>` conversion. Do not
+roll back a committed probe or classify a post-send error with an indiscriminate
+`?`.
+
+All fallible state/capacity/counter/allocation and timeout preparation precedes
+submission. Immediately after `send`/`try_send` returns `Ok(bytes)`, capture the
+public post-send timestamp, commit infallibly, and construct the receipt before
+fallible post-send processing. No suspension, readiness wait, fallible allocation,
+or fallible state operation may intervene between acceptance and commitment;
+the Tokio poll must never return `Pending` after acceptance.
+
+The managed driver consumes receipts for cadence/stagger acceptance and constructs
+`EchoSent` with its scheduled timestamp and timer error. A post-commit failure
+advances cadence and publishes that send before failure cleanup; the underlying
+cause remains a sending failure. `NotCommitted` and `Pending` advance neither
+cadence nor stagger gating. Counters are cumulative accounting, never evidence
+of one operation's commitment.
+
+Tokio retains one prepared probe across cancellation/readiness false positives
+and `WouldBlock`, samples a fresh private anchor on each retry, and clears the
+prepared probe after commitment even when post-send processing fails. Failed
+submissions still invalidate kernel TX ID correlation as documented below.
+
+## Linux kernel TX timestamp capture
+
+On Linux, with the `ancillary` feature, the client best-effort upgrades its
+socket from RX-only `SO_TIMESTAMPING` to RX+TX immediately after a successful
+Open, before the first Echo probe can be sent:
+
+```
+socket created
+    -> RX timestamping configured (RX_SOFTWARE | SOFTWARE)
+    -> Open attempts/retries (untimestamped)
+    -> successful Open
+    -> best-effort enable TX timestamping (+ TX_SOFTWARE | OPT_ID | OPT_TSONLY)
+    -> first Echo probe
+```
+
+`TX_SOFTWARE` asks the kernel for a software send timestamp; `OPT_ID` asks it
+to tag each notification with an automatically incrementing per-socket ID;
+`OPT_TSONLY` means the notification never needs to carry the original
+payload, so a zero-length receive buffer is enough. The upgrade is entirely
+best-effort: if it fails, the client keeps operating on the original RX-only
+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.
+
+### Best-effort kernel-ID correlation
+
+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.
+
+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
+  second session on the same socket, so there is no second epoch of wire
+  sequence numbers to collide with a stale kernel ID.
+- **The one extra send (Close) is harmless.** `Close` sends one datagram
+  after TX timestamping is already enabled, generating one TX timestamp
+  record with no corresponding `wire_seq` (`Close` does not advance
+  `next_wire_seq`). Because the session is terminal immediately after,
+  nothing will ever look up that ID; `record_kernel_tx_timestamp`'s
+  "unknown ID -> ignore" rule discards it safely.
+
+## MSG_ERRQUEUE drains
+
+`receive::linux::error_queue` decodes one `MSG_ERRQUEUE` record at a time
+(`try_recv_error_queue_record`) and classifies it: a genuine send-timestamp
+completion (`TxTimestamp`), a timestamp-origin record that is not a usable
+`SND` completion (`MalformedOrUnsupportedTimestamp` — never treated as
+fatal, since this client only ever requests `TX_SOFTWARE`/`SND`, so anything
+else on that origin is unexpected metadata, not a network error), a genuine
+non-timestamp socket/network error (`SocketError`), or nothing (`Ignored`).
+Origin (`SO_EE_ORIGIN_TIMESTAMPING` or not) is the only thing that decides
+between the last two categories.
+
+`receive::linux::drain_tx_timestamps` reads up to
+`MAX_TX_TIMESTAMP_RECORDS_PER_DRAIN` (32) records per call: nonblocking, one
+record at a time, no heap allocation, stopping early once the queue is
+empty. It is a starvation guard, not a queue-capacity promise — one TX
+timestamp is generated per successful probe, and drains happen at several
+natural choke points, so a modest constant comfortably covers realistic
+backlog. `Client`/`AsyncClient` call it after a successful probe send,
+before processing an inbound reply, and before evaluating timeouts; it never
+waits for a timestamp; an absent timestamp after all of those opportunities
+simply stays absent. A genuine `SocketError` record stops the drain and is
+surfaced as `ClientError::Socket`. During post-send processing it is wrapped in
+`SendProbeError::AfterCommit` with the accepted send's receipt; receive/timeout
+operations retain the ordinary `ClientError` path.
+
+The Tokio adapter uses the same raw nonblocking `recvmsg(MSG_ERRQUEUE |
+MSG_DONTWAIT)` rather than `try_io`/`poll_recv_ready`: error-queue readiness
+is not ordinary read readiness, and driving it through the Tokio reactor
+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>`
+alongside the userspace `sent_at`. It survives pending -> timed-out retention
+(`SessionMachine::record_kernel_tx_timestamp` updates whichever of
+`PendingMap`/`TimedOutMap` still holds the probe) and is otherwise bounded by
+the same limits those maps already enforce — no new unbounded state. First
+valid observation wins on duplicates.
+
+### Pre-send anchor vs. post-send `sent_at` (F-04)
+
+The probe send transaction splits into two timestamps around the socket
+send, not one:
+
+- A **private pre-send anchor**, sampled immediately before the fallible
+  commit preflight (`SessionMachine::finalize_probe_commit`) that must
+  happen before the socket send: timeout deadline `checked_add` arithmetic
+  (so `DurationOverflow` still guarantees nothing was transmitted) and the
+  kernel TX lower-plausibility bound. Its monotonic half becomes
+  `PendingProbe::timeout_at`'s basis; its wall half becomes
+  `PendingProbe::tx_not_before_wall`. It is never exposed publicly.
+- The **public `sent_at`**, a paired wall/monotonic `ClientTimestamp`
+  captured immediately after the socket send returns successfully
+  (`SessionMachine::commit_probe_sent`, which is infallible — all fallible
+  work already happened against the pre-send anchor). This is the RTT
+  endpoint, the userspace upstream-OWD fallback endpoint, `timer_error`'s
+  basis, and the value surfaced on `EchoSent`/`EchoReply`/`EchoLoss`/
+  `LateReply`.
+
+So `timeout_at` is deliberately **not** derived from `sent_at.mono` — it
+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; 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.
+
+**The kernel TX timestamp is eligible for exactly one measurement: the
+upstream (`client_to_server`) one-way delay send endpoint.**
+`compute_one_way`'s private `preferred_send_wall` helper prefers it over the
+userspace `sent_at.wall` sample when
+
+    tx_not_before_wall <= kernel_tx_timestamp <= reply_received_at.wall
+
+(inclusive, compared only against the client's own wall clock — never
+against the remote server's wall timestamp). The lower bound is the
+pre-send `tx_not_before_wall`, not the post-send `sent_at.wall`: a
+legitimate `TX_SOFTWARE` timestamp can be generated while the send syscall
+is still in flight, so it can legitimately precede the post-send `sent_at`
+sample without being implausible. Otherwise, including when no kernel
+timestamp was observed, the upstream endpoint falls back to `sent_at.wall`
+(the post-send sample); a rejected observation is never erased from
+`PendingProbe`, only skipped for that measurement. There is no
+maximum-lag bound: unlike the kernel receive side, legitimate client
+send-to-reply time can exceed a second.
+
+`sent_at` remains the RTT endpoint and the userspace fallback for the
+upstream (`client_to_server`) one-way delay, exactly as before this
+capability existed. It is not an input to the downstream
+(`server_to_client`) one-way delay, which is derived solely from
+`ReceiveMeta::preferred_receive_wall` and the negotiated server send
+timestamp — unaffected by this capability or by F-04. `TX_SOFTWARE` is
+still a software kernel timestamp near the driver handoff, not a NIC
+hardware transmit time. `irtt-stats`'s `ReplySample`
+copies public `sent_at` straight into `client_send_mono`/`client_send_wall_ns`,
+which `send_ipdv_ns` compares across probes for the upstream IPDV component —
+so that component shifts endpoint along with `sent_at` itself (pre-send vs.
+post-send) exactly as RTT and the upstream OWD fallback do; it is not a
+separate invariant. A normal
+reply and a measurable late reply (one whose `PendingProbe` is still
+retained in `TimedOutMap`) apply the identical selection policy; an
+untracked late reply has no retained probe and stays unmeasurable, and a
+kernel timestamp that arrives after a reply has already been processed is
+simply never observed by that reply.

crates/irtt-client/Cargo.toml

@@ -1,25 +1,47 @@
 [package]
 name = "irtt-client"
-version = "0.4.0"
+version = "0.6.0"
 description = "IRTT-compatible Rust client library"
 edition.workspace = true
 license.workspace = true
 rust-version.workspace = true
 repository.workspace = true
 homepage.workspace = true
-readme.workspace = true
+readme = "README.md"
 keywords = ["irtt", "networking", "latency", "rtt"]
 categories = ["network-programming"]
 
 [dependencies]
 irtt-proto.workspace = true
-libc = { version = "0.2.186", optional = true }
-socket2 = { version = "0.6.4", features = ["all"] }
-thiserror = "2.0.18"
+socket2 = { version = "0.6.5", features = ["all"] }
+thiserror = "2.0.21"
+tokio = { version = "1.53.2", default-features = false, features = ["rt", "net", "time", "sync"], optional = true}
+
+[target.'cfg(target_os = "linux")'.dependencies]
+nix = { version = "0.31.3", default-features = false, features = ["net", "uio"], optional = true }
 
 [features]
 default = []
-ancillary = ["dep:libc"]
+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"]
+
+[[example]]
+name = "blocking_client"
+doc-scrape-examples = true
+
+[[example]]
+name = "tokio_client"
+required-features = ["tokio"]
+doc-scrape-examples = true
+
+[[example]]
+name = "managed_client"
+required-features = ["tokio"]
+doc-scrape-examples = true

crates/irtt-client/README.md

@@ -0,0 +1,109 @@
+# irtt-client
+
+Reusable client/session library for IRTT-compatible round-trip-time probing:
+socket lifecycle, open negotiation, probe send/receive, loss/duplicate/late
+classification, and a typed event stream.
+
+## Looking for the CLI?
+
+If you just want to run probes from the command line, use the
+[`irtt-rs`](https://crates.io/crates/irtt-rs) application package instead,
+which installs the `irtt-client` binary. This crate is the library the
+binaries are built on.
+
+## API tiers
+
+- `Client` — runtime-free blocking adapter. No Tokio dependency; this is the
+  default build.
+- `AsyncClient` (feature `tokio`) — low-level Tokio adapter for callers that
+  own a runtime and drive readiness directly.
+- `managed` (feature `tokio`) — a unified managed driver: `ManagedClientTask`
+  / `ManagedClientHandle` for multi-target orchestration under a Tokio
+  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
+sends return `Result<SendReceipt, SendProbeError>` instead of event lists.
+A `SendReceipt` carries the committed sequence, remote, post-send timestamp,
+accepted bytes, and send-call duration. `NotCommitted(ClientError)` guarantees
+no accepted datagram or committed probe; `AfterCommit { receipt, source }`
+preserves the accepted send when subsequent validation or TX processing fails.
+Use `ClientEvent::from(receipt)` for an `EchoSent` event with `scheduled_at` and
+`timer_error` absent; the managed driver supplies those schedule measurements
+and publishes committed sends even when post-send processing fails.
+
+Tokio stays optional: the default build has no runtime and no Tokio
+dependency at all.
+
+See `examples/` in the repository for runnable examples of each tier.
+
+## Reusable configuration
+
+`ClientConfig` contains no endpoint. The low-level APIs take it separately:
+`Client::connect(endpoint, config)` and
+`AsyncClient::connect(endpoint, config).await`, accepting `String` or `&str`
+endpoints. An omitted port defaults to 2112.
+
+Configuration is grouped by ownership:
+
+- `address_family`: `AddressFamily::{Any, Ipv4, Ipv6}`, defaulting to `Any`.
+  It filters remote resolution; `Ipv6` also sets `IPV6_V6ONLY`.
+- `socket`: `SocketConfig` for local bind, device/routing options, and TTL.
+- `request`: `SessionRequest` for duration, interval, length, received stats,
+  timestamps, clock, DSCP, server fill, and run mode.
+- `open`: `OpenPolicy` for attempt `timeouts` and `negotiation` policy.
+- `auth`, `probe_timeout`, and `max_pending_probes`: authentication and local
+  probe tracking policy.
+
+Clone one config to connect to multiple endpoints. Managed targets retain their
+own ID, endpoint, address-family override, and authentication inheritance/override; shared
+`ManagedClientConfig.client` is reusable without endpoint mutation.
+
+`ManagedTargetConfig.address_family` defaults to `None`, inheriting the shared
+family policy. `Some(AddressFamily::Ipv4)`, `Some(AddressFamily::Ipv6)`, or
+`Some(AddressFamily::Any)` overrides it for that target. Every new generation
+resolves the original endpoint again; callers can constrain a hostname without
+replacing it with a resolved IP. Changing the family specification replaces
+that target's generation, including switching between inheritance and an equal
+explicit override. Hostname expansion and discovery are frontend policies.
+
+Blocking receive policy belongs to `Client`:
+`client.set_recv_timeout(Some(duration))?` sets it before or after opening,
+and `client.set_recv_timeout(None)?` restores the default indefinite wait.
+Open attempts use only `open.timeouts`, restoring the adapter setting afterward.
+Async and managed clients have no blocking receive-timeout setting.
+
+This breaks the former flat config, endpoint-in-config, socket family flags,
+and `SocketConfig.recv_timeout` APIs. Use the grouped fields and adapter method
+directly; defaults and protocol/runtime behavior are preserved.
+
+## Authentication
+
+`ClientConfig.auth` is concrete: `Authentication::Unauthenticated` or
+`Authentication::Hmac(HmacKey::new(bytes))`. Keys share their bytes across
+clones and print only `HmacKey([REDACTED])` through `Debug`. Borrowing key
+material requires an explicit `as_bytes()` call. An empty key still selects
+HMAC authentication; textual key syntax belongs to the application.
+
+For managed targets, `ManagedTargetConfig.auth` defaults to `TargetAuth::Inherit`.
+`TargetAuth::Override(Authentication::Unauthenticated)` disables shared
+authentication, and `TargetAuth::Override(Authentication::Hmac(key))` replaces
+the shared key. Initial construction and update planning resolve inheritance
+into concrete session authentication before execution. Switching between
+inheritance and an override replaces the target generation even when their
+resolved authentication is equal.
+
+This replaces the former `ClientConfig.hmac_key` and `ClientAuthConfig` API;
+there are no compatibility aliases.
+
+## Documentation
+
+Full API documentation is on [docs.rs/irtt-client](https://docs.rs/irtt-client).
+
+## Project
+
+Part of [irtt-rs](https://github.com/Lochnair/irtt-rs), an independent Rust
+implementation of an IRTT-compatible protocol stack.

crates/irtt-client/examples/blocking_client.rs

@@ -0,0 +1,134 @@
+//! Runtime-free blocking client example.
+//!
+//! Opens a session against a local IRTT-compatible server, sends a few
+//! probes, and prints the events observed. Uses only [`Client`], which has no
+//! Tokio dependency and works in a default (`--no-default-features`) build.
+//!
+//! Run a server first, then run this example:
+//!
+//! ```text
+//! cargo run -p irtt-rs --bin irtt-server --features server
+//! cargo run -p irtt-client --example blocking_client
+//! ```
+//!
+//! Without a reachable server this exits quickly with an open-timeout error
+//! instead of hanging, because the example shortens `open.timeouts` for a
+//! fast demonstration; a real caller would normally keep the default retry
+//! schedule.
+
+use std::time::{Duration, Instant};
+
+use irtt_client::{Client, ClientConfig, ClientEvent, OpenOutcome, OpenPolicy, SessionRequest};
+
+const RUN_DURATION: Duration = Duration::from_secs(2);
+
+fn main() {
+    let config = ClientConfig {
+        open: OpenPolicy {
+            // A single short attempt keeps this example fast when no server is
+            // reachable; production callers should generally keep the default.
+            timeouts: vec![Duration::from_millis(300)],
+            ..Default::default()
+        },
+        request: SessionRequest {
+            duration: Some(RUN_DURATION),
+            interval: Duration::from_millis(200),
+            ..Default::default()
+        },
+        ..Default::default()
+    };
+
+    let mut client = match Client::connect("127.0.0.1:2112", config) {
+        Ok(client) => client,
+        Err(err) => {
+            eprintln!("failed to prepare client socket: {err}");
+            return;
+        }
+    };
+
+    if let Err(err) = client.set_recv_timeout(Some(Duration::from_millis(100))) {
+        eprintln!("failed to configure receive timeout: {err}");
+        return;
+    }
+
+    let negotiated = match client.open() {
+        Ok(OpenOutcome::Started(started)) => {
+            println!("session opened: {started:?}");
+            started.negotiation
+        }
+        Ok(OpenOutcome::NoTestCompleted(completed)) => {
+            println!("{completed:?}");
+            return;
+        }
+        Err(err) => {
+            eprintln!("open failed (is a server running at 127.0.0.1:2112?): {err}");
+            return;
+        }
+    };
+
+    // This loop owns cadence and duration. The transport sends whenever called.
+    let interval = negotiated.accepted.interval;
+    let start = Instant::now();
+    let end = start
+        + negotiated
+            .accepted
+            .duration
+            .expect("example requests a finite run");
+    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(receipt) => {
+                    print_event(&receipt.into());
+                    while next_send <= Instant::now() {
+                        next_send += interval;
+                    }
+                }
+                Err(err) => {
+                    if let irtt_client::SendProbeError::AfterCommit { receipt, .. } = &err {
+                        print_event(&(*receipt).into());
+                    }
+                    eprintln!("send failed: {err}");
+                    break;
+                }
+            }
+        }
+        match client.recv_once() {
+            Ok(events) => events.iter().for_each(print_event),
+            Err(err) => {
+                eprintln!("receive failed: {err}");
+                break;
+            }
+        }
+        match client.poll_timeouts() {
+            Ok(events) => events.iter().for_each(print_event),
+            Err(err) => {
+                eprintln!("timeout polling failed: {err}");
+                break;
+            }
+        }
+    }
+
+    if client.is_peer_closed() {
+        return;
+    }
+    match client.close() {
+        Ok(events) => events.iter().for_each(print_event),
+        Err(err) => eprintln!("close failed: {err}"),
+    }
+}
+
+fn print_event(event: &ClientEvent) {
+    match event {
+        ClientEvent::EchoReply { seq, rtt, .. } => {
+            println!("seq {seq}: rtt {:?}", rtt.effective);
+        }
+        ClientEvent::EchoLoss { seq, .. } => println!("seq {seq}: lost"),
+        other => println!("{other:?}"),
+    }
+}

crates/irtt-client/examples/managed_client.rs

@@ -0,0 +1,79 @@
+//! Managed multi-target client example (`tokio` feature).
+//!
+//! [`BlockingManagedClient`] runs one or more targets under a dedicated
+//! current-thread Tokio runtime and exposes a synchronous handle, so a caller
+//! that does not want to touch Tokio directly can still get managed
+//! multi-target orchestration, retries, and a lossy event stream.
+//!
+//! Run a server first, then run this example:
+//!
+//! ```text
+//! cargo run -p irtt-rs --bin irtt-server --features server
+//! cargo run -p irtt-client --example managed_client --features tokio
+//! ```
+//!
+//! This example does not wait for the managed run to finish naturally: it
+//! requests a stop after a fixed short window so it exits promptly even
+//! without a reachable server.
+
+use std::time::Duration;
+
+use irtt_client::managed::{
+    BlockingManagedClient, ManagedClientConfig, ManagedCompletionPolicy, ManagedEvent,
+    ManagedTargetConfig,
+};
+use irtt_client::{ClientConfig, OpenPolicy, SessionRequest};
+
+fn main() {
+    let config = ManagedClientConfig {
+        client: ClientConfig {
+            open: OpenPolicy {
+                timeouts: vec![Duration::from_millis(300)],
+                ..Default::default()
+            },
+            request: SessionRequest {
+                duration: None,
+                interval: Duration::from_millis(200),
+                ..Default::default()
+            },
+            ..Default::default()
+        },
+        completion: ManagedCompletionPolicy::ExplicitStop,
+        ..Default::default()
+    };
+    let targets = vec![ManagedTargetConfig::new("local", "127.0.0.1:2112")];
+
+    let (owner, mut events) = match BlockingManagedClient::start_with_subscription(config, targets)
+    {
+        Ok(started) => started,
+        Err(err) => {
+            eprintln!("failed to start managed client: {err}");
+            return;
+        }
+    };
+
+    let stop_after = Duration::from_secs(1);
+    let deadline = std::time::Instant::now() + stop_after;
+    while std::time::Instant::now() < deadline {
+        match events.try_recv() {
+            Ok(event) => print_event(&event),
+            Err(_) => std::thread::sleep(Duration::from_millis(50)),
+        }
+    }
+
+    // `stop()` requests the stop synchronously; the returned receipt is only
+    // useful for awaiting durable acknowledgement, which this blocking
+    // example does not need.
+    std::mem::drop(owner.handle().stop());
+    match owner.join() {
+        Ok(outcome) => println!("managed run ended: {:?}", outcome.end_reason),
+        Err(err) => eprintln!("managed worker did not join cleanly: {err}"),
+    }
+}
+
+fn print_event(event: &ManagedEvent) {
+    match event {
+        ManagedEvent::Client { target, event } => println!("{}: {event:?}", target.id),
+        other => println!("{other:?}"),
+    }
+}

crates/irtt-client/examples/tokio_client.rs

@@ -0,0 +1,165 @@
+//! Low-level Tokio client example (`tokio` feature).
+//!
+//! Drives [`AsyncClient`] directly on a caller-owned runtime. This is the
+//! adapter to reach for when you already have a Tokio runtime and want to
+//! await sends/receives yourself, rather than use the higher-level `managed`
+//! driver (see the `managed_client` example).
+//!
+//! Run a server first, then run this example:
+//!
+//! ```text
+//! cargo run -p irtt-rs --bin irtt-server --features server
+//! cargo run -p irtt-client --example tokio_client --features tokio
+//! ```
+//!
+//! Without a reachable server this exits quickly with an open-timeout error
+//! instead of hanging, because the example shortens `open.timeouts` for a
+//! fast demonstration.
+
+use std::time::{Duration, Instant};
+
+use irtt_client::{
+    AsyncClient, ClientConfig, ClientEvent, OpenOutcome, OpenPolicy, SessionRequest,
+};
+
+/// Upper bound on how long the receive wait can go without also calling
+/// `poll_timeouts()`. `AsyncClient` does not expose the earliest pending
+/// probe's own timeout deadline, so this example polls on a short fixed
+/// cadence instead of waiting for the full `probe_timeout()` from whenever
+/// this loop last ran — that would let poll_timeouts() classify a lost
+/// probe (and its dependent statistics/session state) far later than it
+/// actually became lost.
+const TIMEOUT_POLL_INTERVAL: Duration = Duration::from_millis(50);
+
+fn main() {
+    let runtime = tokio::runtime::Builder::new_current_thread()
+        .enable_io()
+        .enable_time()
+        .build()
+        .expect("failed to build Tokio runtime");
+
+    runtime.block_on(run());
+}
+
+async fn run() {
+    let config = ClientConfig {
+        open: OpenPolicy {
+            // A single short attempt keeps this example fast when no server is
+            // reachable; production callers should generally keep the default.
+            timeouts: vec![Duration::from_millis(300)],
+            ..Default::default()
+        },
+        request: SessionRequest {
+            duration: Some(Duration::from_secs(2)),
+            interval: Duration::from_millis(200),
+            ..Default::default()
+        },
+        ..Default::default()
+    };
+
+    let mut client = match AsyncClient::connect("127.0.0.1:2112", config).await {
+        Ok(client) => client,
+        Err(err) => {
+            eprintln!("failed to prepare client socket: {err}");
+            return;
+        }
+    };
+
+    let negotiated = match client.open().await {
+        Ok(OpenOutcome::Started(started)) => {
+            println!("session opened: {started:?}");
+            started.negotiation
+        }
+        Ok(OpenOutcome::NoTestCompleted(completed)) => {
+            println!("{completed:?}");
+            return;
+        }
+        Err(err) => {
+            eprintln!("open failed (is a server running at 127.0.0.1:2112?): {err}");
+            return;
+        }
+    };
+
+    // This loop owns cadence and duration. The transport sends whenever called.
+    let interval = negotiated.accepted.interval;
+    let start = Instant::now();
+    let end = start
+        + negotiated
+            .accepted
+            .duration
+            .expect("example requests a finite run");
+    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 = (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()
+            .unwrap();
+
+        let recv_result = tokio::select! {
+            events = client.recv() => Some(events),
+            () = tokio::time::sleep_until(tokio::time::Instant::from_std(wake_at)) => None,
+        };
+        if let Some(result) = recv_result {
+            match result {
+                Ok(events) => events.iter().for_each(print_event),
+                Err(err) => {
+                    eprintln!("receive failed: {err}");
+                    break;
+                }
+            }
+        }
+
+        if Instant::now() < end && Instant::now() >= next_send {
+            match client.send_probe().await {
+                Ok(receipt) => {
+                    print_event(&receipt.into());
+                    while next_send <= Instant::now() {
+                        next_send += interval;
+                    }
+                }
+                Err(err) => {
+                    if let irtt_client::SendProbeError::AfterCommit { receipt, .. } = &err {
+                        print_event(&(*receipt).into());
+                    }
+                    eprintln!("send failed: {err}");
+                    break;
+                }
+            }
+        }
+        match client.poll_timeouts() {
+            Ok(events) => events.iter().for_each(print_event),
+            Err(err) => {
+                eprintln!("timeout polling failed: {err}");
+                break;
+            }
+        }
+    }
+
+    if client.is_peer_closed() {
+        return;
+    }
+    match client.close().await {
+        Ok(events) => events.iter().for_each(print_event),
+        Err(err) => eprintln!("close failed: {err}"),
+    }
+}
+
+fn print_event(event: &ClientEvent) {
+    match event {
+        ClientEvent::EchoReply { seq, rtt, .. } => {
+            println!("seq {seq}: rtt {:?}", rtt.effective);
+        }
+        ClientEvent::EchoLoss { seq, .. } => println!("seq {seq}: lost"),
+        other => println!("{other:?}"),
+    }
+}

crates/irtt-client/src/async_client.rs

@@ -0,0 +1,902 @@
+use std::{
+    future::{poll_fn, Future},
+    io,
+    net::SocketAddr,
+    pin::Pin,
+    task::{Context, Poll},
+    time::{Duration, Instant},
+};
+
+use tokio::time;
+
+use crate::{
+    client::validate_datagram_length,
+    config::ClientConfig,
+    error::ClientError,
+    event::{ClientEvent, OpenOutcome},
+    receive::{drain_tx_timestamps, try_enable_tx_timestamping, try_recv_tokio_datagram},
+    session::machine::{
+        recv_buffer_size, OpenDatagramDisposition, PreparedOpenAcceptance, PreparedOpenRequest,
+        PreparedProbe, SessionMachine, TimeoutBatch, MAX_OPEN_PACKET_SIZE,
+    },
+    socket::{connect_tokio_udp_socket, resolve_remote_tokio},
+    socket_options::{apply_traffic_class_to_tokio_socket, clear_dscp_on_tokio_socket},
+    timing::ClientTimestamp,
+    SendProbeError, SendReceipt,
+};
+
+/// Maximum amount of immediately available opening work performed by one poll.
+///
+/// Opening may consume ignored UDP datagrams, roll over an expired attempt, or
+/// encounter readiness false positives without ever awaiting.  Bound that work
+/// so one managed target cannot retain the current-thread runtime.
+const OPEN_POLL_WORK_BUDGET: usize = 64;
+
+/// Maximum immediately available receive work performed by one
+/// [`AsyncClient::poll_recv`] poll.
+///
+/// A `WouldBlock` readiness false positive is naturally bounded: `try_io`
+/// clears the reactor's readiness on `WouldBlock`, so the next
+/// `poll_recv_ready` genuinely awaits a fresh edge. An `Interrupted`
+/// (`EINTR`) nonblocking `recvmsg` does not clear that readiness — the
+/// syscall was interrupted, not told there was nothing to read — so without
+/// an explicit bound a sustained signal delivery rate could otherwise retry
+/// in a tight loop on this executor thread. Bounding both cases the same way
+/// this crate already bounds open-attempt work keeps that impossible.
+const RECV_POLL_WORK_BUDGET: usize = 64;
+
+#[derive(Debug)]
+struct PreparedAsyncOpen {
+    machine: PreparedOpenAcceptance,
+    recv_buffer_len: Option<usize>,
+    negotiated_traffic_class: Option<u8>,
+}
+
+#[derive(Debug)]
+struct PreparedAsyncOpenFailure {
+    primary: ClientError,
+    machine: PreparedOpenAcceptance,
+}
+
+#[derive(Debug)]
+enum AsyncOpenCleanup {
+    Acceptance {
+        primary: ClientError,
+        packet: Option<Box<[u8]>>,
+    },
+    Adapter(Box<PreparedAsyncOpenFailure>),
+}
+
+impl AsyncOpenCleanup {
+    fn packet(&self) -> Option<&[u8]> {
+        match self {
+            Self::Acceptance { packet, .. } => packet.as_deref(),
+            Self::Adapter(failure) => failure.machine.cleanup_close_packet(),
+        }
+    }
+
+    fn into_primary(self) -> ClientError {
+        match self {
+            Self::Acceptance { primary, .. } => primary,
+            Self::Adapter(failure) => failure.primary,
+        }
+    }
+}
+
+/// Owned state for one asynchronous open transaction.
+///
+/// This state deliberately contains no reference to [`AsyncClient`], allowing
+/// a managed target to store the client and opening state side by side.
+#[derive(Debug)]
+pub(crate) struct AsyncOpenState {
+    attempt: usize,
+    deadline: Option<Instant>,
+    deadline_timer: Option<Pin<Box<time::Sleep>>>,
+    request_submitted: bool,
+    stop_after_current_attempt: bool,
+    stopped_after_current_attempt: bool,
+    buffer: [u8; MAX_OPEN_PACKET_SIZE],
+    cleanup: Option<AsyncOpenCleanup>,
+}
+
+impl AsyncOpenState {
+    pub(crate) fn new() -> Self {
+        Self {
+            attempt: 0,
+            deadline: None,
+            deadline_timer: None,
+            request_submitted: false,
+            stop_after_current_attempt: false,
+            stopped_after_current_attempt: false,
+            buffer: [0_u8; MAX_OPEN_PACKET_SIZE],
+            cleanup: None,
+        }
+    }
+
+    fn start_attempt(&mut self, timeout: Duration) -> Result<(), ClientError> {
+        let deadline = Instant::now()
+            .checked_add(timeout)
+            .ok_or(ClientError::DurationOverflow)?;
+        self.deadline = Some(deadline);
+        self.deadline_timer = Some(Box::pin(time::sleep_until(deadline.into())));
+        self.request_submitted = false;
+        Ok(())
+    }
+
+    fn finish_attempt(&mut self) {
+        self.attempt += 1;
+        self.deadline = None;
+        self.deadline_timer = None;
+        self.request_submitted = false;
+        self.stopped_after_current_attempt = self.stop_after_current_attempt;
+    }
+
+    pub(crate) fn has_in_flight_work(&self) -> bool {
+        self.request_submitted || self.cleanup.is_some()
+    }
+
+    pub(crate) fn request_stop_after_current_attempt(&mut self) {
+        self.stop_after_current_attempt = true;
+    }
+
+    pub(crate) fn stopped_after_current_attempt(&self) -> bool {
+        self.stopped_after_current_attempt
+    }
+
+    fn deadline(&self) -> Instant {
+        self.deadline
+            .expect("an open attempt has an active deadline")
+    }
+
+    fn deadline_timer(&mut self) -> &mut Pin<Box<time::Sleep>> {
+        self.deadline_timer
+            .as_mut()
+            .expect("an open attempt has an active deadline timer")
+    }
+}
+
+/// 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("127.0.0.1:2112", 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,
+    remote: SocketAddr,
+    recv_buffer: Vec<u8>,
+    applied_traffic_class: Option<u8>,
+    prepared_open: Option<PreparedOpenRequest>,
+    prepared_probe: Option<PreparedProbe>,
+    /// 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,
+}
+
+impl AsyncClient {
+    /// Resolve the endpoint and construct one connected Tokio UDP
+    /// socket.
+    ///
+    /// Polling this future without a current Tokio runtime returns
+    /// [`ClientError::NoTokioRuntime`]. A runtime without enabled I/O or time
+    /// drivers is outside this type's runtime contract.
+    ///
+    /// The endpoint accepts a name or address; an omitted port defaults to 2112.
+    /// IPv6 literals may be bracketed or unbracketed with the default port.
+    /// The reusable config contains no endpoint identity.
+    pub async fn connect(
+        endpoint: impl AsRef<str>,
+        config: ClientConfig,
+    ) -> Result<Self, ClientError> {
+        tokio::runtime::Handle::try_current().map_err(|_| ClientError::NoTokioRuntime)?;
+        config.open.validate()?;
+        let remote = resolve_remote_tokio(endpoint.as_ref(), config.address_family).await?;
+        let machine = SessionMachine::new(config.clone(), remote)?;
+        let prepared_open = machine.prepare_open_request()?;
+        let socket = connect_tokio_udp_socket(&config.socket, remote, config.address_family)?;
+
+        Ok(Self {
+            socket,
+            machine,
+            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,
+        })
+    }
+
+    /// Perform the IRTT open exchange.
+    ///
+    /// Each configured attempt uses one absolute deadline for one successful
+    /// request submission and all replies inspected during that attempt.
+    /// Malformed, unrelated, wrong-direction, and unauthenticated datagrams are
+    /// ignored without resending the request.
+    ///
+    /// Dropping this future before trusted acceptance leaves the local machine
+    /// 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 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
+    /// probe without advancing state before kernel acceptance. Cancellation or
+    /// `WouldBlock` before submission is uncommitted. After acceptance there is
+    /// no suspension before infallible commitment, and the prepared probe is
+    /// cleared even if post-send processing returns [`SendProbeError::AfterCommit`].
+    /// That failure retains the authoritative receipt; earlier failures return
+    /// [`SendProbeError::NotCommitted`].
+    pub async fn send_probe(&mut self) -> Result<SendReceipt, SendProbeError> {
+        poll_fn(|cx| self.poll_send_probe(cx)).await
+    }
+
+    /// Await and classify one complete UDP datagram.
+    ///
+    /// State is validated before readiness is awaited. Readiness false positives
+    /// retry without changing protocol state. Authenticated peer-close events
+    /// remain authoritative even if best-effort DSCP cleanup fails.
+    pub async fn recv(&mut self) -> Result<Vec<ClientEvent>, ClientError> {
+        poll_fn(|cx| self.poll_recv(cx)).await
+    }
+
+    /// Poll protocol timeouts using a newly captured monotonic timestamp.
+    pub fn poll_timeouts(&mut self) -> Result<Vec<ClientEvent>, ClientError> {
+        self.poll_timeouts_at(Instant::now())
+    }
+
+    /// Poll protocol timeouts using the caller's monotonic timestamp.
+    pub fn poll_timeouts_at(&mut self, now: Instant) -> Result<Vec<ClientEvent>, ClientError> {
+        self.drain_tx_timestamps()?;
+        self.machine.poll_timeouts_at(now)
+    }
+
+    pub(crate) fn poll_timeouts_bounded_at(
+        &mut self,
+        now: Instant,
+        limit: usize,
+    ) -> Result<TimeoutBatch, ClientError> {
+        self.drain_tx_timestamps()?;
+        self.machine.poll_timeouts_bounded_at(now, limit)
+    }
+
+    /// Send the retained close packet and commit local close exactly once.
+    ///
+    /// DSCP is cleared only after write readiness and immediately before the
+    /// nonblocking send attempt. A `WouldBlock` result restores it before the
+    /// next await, so dropping this future at a suspension point cannot leave
+    /// an otherwise-open session with cleared DSCP.
+    pub async fn close(&mut self) -> Result<Vec<ClientEvent>, ClientError> {
+        poll_fn(|cx| self.poll_close(cx)).await
+    }
+
+    pub(crate) fn poll_open(
+        &mut self,
+        state: &mut AsyncOpenState,
+        cx: &mut Context<'_>,
+    ) -> Poll<Result<OpenOutcome, ClientError>> {
+        if self.prepared_open.is_none() {
+            if let Err(error) = self.machine.prepare_open_request() {
+                return Poll::Ready(Err(error));
+            }
+            unreachable!("connected async clients retain an open request");
+        }
+
+        for _ in 0..OPEN_POLL_WORK_BUDGET {
+            if state.cleanup.is_some() {
+                return self.poll_open_cleanup(state, cx);
+            }
+
+            let attempt_count = self.machine.config().open.timeouts.len();
+            if state.attempt >= attempt_count {
+                return Poll::Ready(Err(ClientError::OpenTimeout));
+            }
+            if state.stop_after_current_attempt && state.deadline.is_none() {
+                state.stopped_after_current_attempt = true;
+                return Poll::Ready(Err(ClientError::OpenTimeout));
+            }
+            if state.deadline.is_none() {
+                let timeout = self.machine.config().open.timeouts[state.attempt];
+                if let Err(error) = state.start_attempt(timeout) {
+                    return Poll::Ready(Err(error));
+                }
+            }
+
+            if !state.request_submitted {
+                match poll_writable_until(&self.socket, state.deadline_timer(), cx) {
+                    Poll::Pending => return Poll::Pending,
+                    Poll::Ready(Err(error)) => return Poll::Ready(Err(error)),
+                    Poll::Ready(Ok(false)) => {
+                        state.finish_attempt();
+                        continue;
+                    }
+                    Poll::Ready(Ok(true)) => {}
+                }
+
+                let request = self
+                    .prepared_open
+                    .as_ref()
+                    .expect("connected clients retain their prepared open request");
+                let send_result = self.socket.try_send(&request.bytes);
+                match send_result {
+                    Ok(bytes) => {
+                        state.request_submitted = true;
+                        if let Err(error) = validate_datagram_length(request.bytes.len(), bytes) {
+                            return Poll::Ready(Err(error));
+                        }
+                    }
+                    Err(error) if error.kind() == io::ErrorKind::WouldBlock => continue,
+                    Err(error) => return Poll::Ready(Err(ClientError::Socket(error))),
+                }
+            }
+
+            match poll_readable_until(&self.socket, state.deadline_timer(), cx) {
+                Poll::Pending => return Poll::Pending,
+                Poll::Ready(Err(error)) => return Poll::Ready(Err(error)),
+                Poll::Ready(Ok(false)) => {
+                    state.finish_attempt();
+                    if state.stopped_after_current_attempt() {
+                        return Poll::Ready(Err(ClientError::OpenTimeout));
+                    }
+                    continue;
+                }
+                Poll::Ready(Ok(true)) => {}
+            }
+
+            let datagram = match try_recv_tokio_datagram(&self.socket, &mut state.buffer) {
+                Ok(datagram) => datagram,
+                // WouldBlock is a readiness false positive; Interrupted
+                // (EINTR) is a transient nonblocking-recvmsg interruption.
+                // Both retry through the surrounding `OPEN_POLL_WORK_BUDGET`-
+                // bounded loop above, which re-checks readiness before the
+                // next attempt and yields back to the executor once that
+                // budget is exhausted.
+                Err(error)
+                    if matches!(
+                        error.kind(),
+                        io::ErrorKind::WouldBlock | io::ErrorKind::Interrupted
+                    ) =>
+                {
+                    continue
+                }
+                Err(error) => return Poll::Ready(Err(ClientError::Socket(error))),
+            };
+            if datagram.received_at.mono > state.deadline() {
+                state.finish_attempt();
+                if state.stopped_after_current_attempt() {
+                    return Poll::Ready(Err(ClientError::OpenTimeout));
+                }
+                continue;
+            }
+
+            let reply = match self
+                .machine
+                .inspect_open_datagram(&state.buffer[..datagram.len])
+            {
+                Ok(OpenDatagramDisposition::Ignore) => continue,
+                Ok(OpenDatagramDisposition::Trusted(reply)) => reply,
+                Err(error) => return Poll::Ready(Err(error)),
+            };
+            let machine = match self
+                .machine
+                .prepare_open_acceptance(reply, datagram.received_at)
+            {
+                Ok(machine) => machine,
+                Err(failure) => {
+                    state.cleanup = Some(AsyncOpenCleanup::Acceptance {
+                        primary: failure.primary,
+                        packet: failure.cleanup_close,
+                    });
+                    continue;
+                }
+            };
+            let prepared = match self.prepare_async_open(machine) {
+                Ok(prepared) => prepared,
+                Err(failure) => {
+                    state.cleanup = Some(AsyncOpenCleanup::Adapter(failure));
+                    continue;
+                }
+            };
+            return Poll::Ready(Ok(self.commit_async_open(prepared)));
+        }
+
+        // We deliberately truncated known immediate opening work.  Arrange for
+        // another poll even if no new socket-readiness edge occurs.
+        cx.waker().wake_by_ref();
+        Poll::Pending
+    }
+
+    pub(crate) fn poll_send_probe(
+        &mut self,
+        cx: &mut Context<'_>,
+    ) -> Poll<Result<SendReceipt, SendProbeError>> {
+        if let Err(error) = self.machine.ensure_open() {
+            return Poll::Ready(Err(SendProbeError::NotCommitted(error)));
+        }
+        if self.prepared_probe.is_none() {
+            match self.machine.prepare_probe() {
+                Ok(prepared) => self.prepared_probe = Some(prepared),
+                Err(error) => return Poll::Ready(Err(SendProbeError::NotCommitted(error))),
+            }
+        }
+        loop {
+            match self.socket.poll_send_ready(cx) {
+                Poll::Pending => return Poll::Pending,
+                Poll::Ready(Ok(())) => {}
+                Poll::Ready(Err(error)) => {
+                    return Poll::Ready(Err(SendProbeError::NotCommitted(ClientError::Socket(
+                        error,
+                    ))));
+                }
+            }
+
+            let prepared = self
+                .prepared_probe
+                .as_ref()
+                .expect("prepared probe was retained across readiness");
+            let machine_preflight = match self.machine.preflight_probe_commit(prepared) {
+                Ok(preflight) => preflight,
+                Err(error) => return Poll::Ready(Err(SendProbeError::NotCommitted(error))),
+            };
+            let expected_bytes = prepared.bytes.len();
+
+            // 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).
+            let send_anchor = ClientTimestamp::now();
+            let machine_commit = match self
+                .machine
+                .finalize_probe_commit(machine_preflight, send_anchor)
+            {
+                Ok(commit) => commit,
+                Err(error) => return Poll::Ready(Err(SendProbeError::NotCommitted(error))),
+            };
+            let send_call_start = Instant::now();
+            let send_result = self.socket.try_send(&prepared.bytes);
+            let bytes = match send_result {
+                Ok(bytes) => bytes,
+                // 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 => {
+                    self.machine.invalidate_kernel_tx_correlation();
+                    continue;
+                }
+                Err(error) => {
+                    self.machine.invalidate_kernel_tx_correlation();
+                    return Poll::Ready(Err(SendProbeError::NotCommitted(ClientError::Socket(
+                        error,
+                    ))));
+                }
+            };
+            let send_finished_at = Instant::now();
+
+            // Public post-send measurement, captured only after the
+            // successful send above. The subsequent machine commit
+            // is infallible.
+            let sent_at = ClientTimestamp::now();
+            let sent = self
+                .machine
+                .commit_probe_sent(machine_commit, sent_at, bytes);
+            self.prepared_probe = None;
+            let send_call = send_finished_at.saturating_duration_since(send_call_start);
+
+            let receipt = SendReceipt {
+                seq: sent.seq,
+                remote: self.remote,
+                sent_at: sent.sent_at,
+                bytes: sent.bytes,
+                send_call,
+            };
+            if let Err(source) = validate_datagram_length(expected_bytes, bytes) {
+                return Poll::Ready(Err(SendProbeError::AfterCommit {
+                    receipt,
+                    source: Box::new(source),
+                }));
+            }
+            if let Err(source) = self.drain_tx_timestamps() {
+                return Poll::Ready(Err(SendProbeError::AfterCommit {
+                    receipt,
+                    source: Box::new(source),
+                }));
+            }
+            return Poll::Ready(Ok(receipt));
+        }
+    }
+
+    pub(crate) fn poll_recv(
+        &mut self,
+        cx: &mut Context<'_>,
+    ) -> Poll<Result<Vec<ClientEvent>, ClientError>> {
+        if let Err(error) = self.machine.ensure_open() {
+            return Poll::Ready(Err(error));
+        }
+
+        for _ in 0..RECV_POLL_WORK_BUDGET {
+            match self.socket.poll_recv_ready(cx) {
+                Poll::Pending => return Poll::Pending,
+                Poll::Ready(Ok(())) => {}
+                Poll::Ready(Err(error)) => {
+                    return Poll::Ready(Err(ClientError::Socket(error)));
+                }
+            }
+
+            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
+                // positive and an interrupted nonblocking recvmsg retry
+                // within this bounded loop rather than failing the receive.
+                Err(error)
+                    if matches!(
+                        error.kind(),
+                        io::ErrorKind::WouldBlock | io::ErrorKind::Interrupted
+                    ) =>
+                {
+                    continue
+                }
+                Err(error) => return Poll::Ready(Err(ClientError::Socket(error))),
+            };
+
+            // One final bounded drain before processing the reply, so a TX
+            // timestamp that raced the reply is still associated with its
+            // probe before that probe is looked up and possibly removed
+            // below.
+            if let Err(error) = self.drain_tx_timestamps() {
+                return Poll::Ready(Err(error));
+            }
+
+            let events = match self.machine.process_received_echo_packet(
+                &self.recv_buffer[..datagram.len],
+                datagram.received_at,
+                datagram.meta,
+            ) {
+                Ok(events) => events,
+                Err(error) => return Poll::Ready(Err(error)),
+            };
+            if self.machine.is_peer_closed() {
+                self.prepared_probe = None;
+                if clear_dscp_on_tokio_socket(&self.socket, self.remote).is_ok() {
+                    self.applied_traffic_class = None;
+                }
+            }
+            return Poll::Ready(Ok(events));
+        }
+
+        // Truncated known immediate receive work, exactly as `poll_open`
+        // does: arrange for another poll even if no new socket-readiness
+        // edge occurs, rather than spinning this executor thread further.
+        cx.waker().wake_by_ref();
+        Poll::Pending
+    }
+
+    pub(crate) fn poll_close(
+        &mut self,
+        cx: &mut Context<'_>,
+    ) -> Poll<Result<Vec<ClientEvent>, ClientError>> {
+        loop {
+            let prepared = match self.machine.prepare_close() {
+                Ok(prepared) => prepared,
+                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 {
+                    operation: "close event result",
+                    source,
+                }));
+            }
+            let previous_traffic_class = self.applied_traffic_class;
+            let expected_bytes = prepared.bytes.len();
+
+            match self.socket.poll_send_ready(cx) {
+                Poll::Pending => return Poll::Pending,
+                Poll::Ready(Ok(())) => {}
+                Poll::Ready(Err(error)) => {
+                    return Poll::Ready(Err(ClientError::Socket(error)));
+                }
+            }
+            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);
+            let send_result = self.socket.try_send(prepared.bytes);
+            let bytes = match send_result {
+                Ok(bytes) => bytes,
+                Err(error) if error.kind() == io::ErrorKind::WouldBlock => {
+                    if let Err(error) = rollback.restore() {
+                        return Poll::Ready(Err(error));
+                    }
+
+                    continue;
+                }
+                Err(error) => return Poll::Ready(Err(ClientError::Socket(error))),
+            };
+
+            let close_sent_at = ClientTimestamp::now();
+
+            let event = self
+                .machine
+                .commit_local_close(prepared.commit, close_sent_at);
+            rollback.disarm();
+            self.prepared_probe = None;
+            self.applied_traffic_class = None;
+
+            if let Err(error) = validate_datagram_length(expected_bytes, bytes) {
+                return Poll::Ready(Err(error));
+            }
+            events.push(event);
+            return Poll::Ready(Ok(events));
+        }
+    }
+
+    /// Return the configured local probe timeout.
+    pub fn probe_timeout(&self) -> Duration {
+        self.machine.probe_timeout()
+    }
+
+    /// Accepted semantics and exact peer parameters of the currently live session.
+    ///
+    /// Returns `None` before Open, after Close, and after no-test completion.
+    pub fn negotiation(&self) -> Option<&crate::NegotiationResult> {
+        self.machine.negotiation()
+    }
+
+    /// 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.
+    pub fn is_peer_closed(&self) -> bool {
+        self.machine.is_peer_closed()
+    }
+
+    pub(crate) fn remote_addr(&self) -> SocketAddr {
+        self.remote
+    }
+
+    pub(crate) fn packets_sent(&self) -> u64 {
+        self.machine.packets_sent()
+    }
+
+    /// Earliest timeout deadline among probes still awaiting a reply.
+    pub fn next_probe_timeout_deadline(&self) -> Option<Instant> {
+        self.machine.next_probe_timeout_deadline()
+    }
+
+    pub(crate) fn latest_probe_timeout_deadline(&self) -> Option<Instant> {
+        self.machine.latest_probe_timeout_deadline()
+    }
+
+    pub(crate) fn discard_prepared_probe(&mut self) {
+        self.prepared_probe = None;
+    }
+
+    fn prepare_async_open(
+        &mut self,
+        machine: PreparedOpenAcceptance,
+    ) -> Result<PreparedAsyncOpen, Box<PreparedAsyncOpenFailure>> {
+        let Some(negotiated) = machine.normal_negotiated() else {
+            return Ok(PreparedAsyncOpen {
+                machine,
+                recv_buffer_len: None,
+                negotiated_traffic_class: None,
+            });
+        };
+        let recv_buffer_len = match recv_buffer_size(self.machine.has_hmac(), Some(negotiated)) {
+            Ok(size) => size,
+            Err(primary) => {
+                return Err(Box::new(PreparedAsyncOpenFailure { primary, machine }));
+            }
+        };
+        let negotiated_traffic_class = negotiated.accepted.dscp << 2;
+        let additional = recv_buffer_len.saturating_sub(self.recv_buffer.len());
+        if let Err(source) = self.recv_buffer.try_reserve(additional) {
+            return Err(Box::new(PreparedAsyncOpenFailure {
+                primary: ClientError::AllocationFailed {
+                    operation: "negotiated receive buffer",
+                    source,
+                },
+                machine,
+            }));
+        }
+
+        let dscp_result = apply_traffic_class_to_tokio_socket(
+            &self.socket,
+            self.remote,
+            negotiated_traffic_class,
+        );
+        if let Err(primary) = dscp_result {
+            self.restore_dscp_best_effort(self.applied_traffic_class);
+            return Err(Box::new(PreparedAsyncOpenFailure { primary, machine }));
+        }
+
+        Ok(PreparedAsyncOpen {
+            machine,
+            recv_buffer_len: Some(recv_buffer_len),
+            negotiated_traffic_class: Some(negotiated_traffic_class),
+        })
+    }
+
+    fn commit_async_open(&mut self, prepared: PreparedAsyncOpen) -> OpenOutcome {
+        if let Some(recv_buffer_len) = prepared.recv_buffer_len {
+            self.recv_buffer.resize(recv_buffer_len, 0);
+        }
+        let outcome = self.machine.commit_open(prepared.machine);
+
+        self.applied_traffic_class = prepared.negotiated_traffic_class;
+        self.prepared_open = None;
+        self.tx_timestamping_enabled = try_enable_tx_timestamping(&self.socket);
+        outcome
+    }
+
+    /// See `Client::drain_tx_timestamps` in `client.rs`: same bounded,
+    /// nonblocking, best-effort drain, adapted to the Tokio socket.
+    fn drain_tx_timestamps(&mut self) -> Result<(), ClientError> {
+        if !self.tx_timestamping_enabled {
+            return Ok(());
+        }
+        let machine = &mut self.machine;
+        drain_tx_timestamps(&self.socket, |id, timestamp| {
+            machine.record_kernel_tx_timestamp(id, timestamp);
+        })
+        .map_err(ClientError::Socket)
+    }
+
+    fn poll_open_cleanup(
+        &self,
+        state: &mut AsyncOpenState,
+        cx: &mut Context<'_>,
+    ) -> Poll<Result<OpenOutcome, ClientError>> {
+        let Some(packet) = state
+            .cleanup
+            .as_ref()
+            .expect("cleanup polling requires a retained primary error")
+            .packet()
+        else {
+            return Poll::Ready(Err(state.cleanup.take().unwrap().into_primary()));
+        };
+        let send_result = self.socket.try_send(packet);
+        match send_result {
+            Ok(_) => return Poll::Ready(Err(state.cleanup.take().unwrap().into_primary())),
+            Err(error) if error.kind() == io::ErrorKind::WouldBlock => {}
+            Err(_) => return Poll::Ready(Err(state.cleanup.take().unwrap().into_primary())),
+        }
+
+        match poll_writable_until(&self.socket, state.deadline_timer(), cx) {
+            Poll::Pending => Poll::Pending,
+            Poll::Ready(Ok(true)) => {
+                // Retain cleanup state and resume the send in a fresh poll.  A
+                // writable readiness false positive must not spin this future.
+                cx.waker().wake_by_ref();
+                Poll::Pending
+            }
+            Poll::Ready(Ok(false) | Err(_)) => {
+                Poll::Ready(Err(state.cleanup.take().unwrap().into_primary()))
+            }
+        }
+    }
+
+    fn restore_dscp_best_effort(&self, previous_traffic_class: Option<u8>) {
+        let _ = match previous_traffic_class {
+            Some(traffic_class) => {
+                apply_traffic_class_to_tokio_socket(&self.socket, self.remote, traffic_class)
+            }
+            None => clear_dscp_on_tokio_socket(&self.socket, self.remote),
+        };
+    }
+}
+
+struct DscpRollback<'a> {
+    socket: &'a tokio::net::UdpSocket,
+    remote: SocketAddr,
+    previous_traffic_class: Option<u8>,
+    armed: bool,
+}
+
+impl<'a> DscpRollback<'a> {
+    fn armed(
+        socket: &'a tokio::net::UdpSocket,
+        remote: SocketAddr,
+        previous_traffic_class: Option<u8>,
+    ) -> Self {
+        Self {
+            socket,
+            remote,
+            previous_traffic_class,
+            armed: true,
+        }
+    }
+
+    fn restore(&mut self) -> Result<(), ClientError> {
+        if !self.armed {
+            return Ok(());
+        }
+
+        match self.previous_traffic_class {
+            Some(traffic_class) => {
+                apply_traffic_class_to_tokio_socket(self.socket, self.remote, traffic_class)?
+            }
+            None => clear_dscp_on_tokio_socket(self.socket, self.remote)?,
+        }
+        self.armed = false;
+        Ok(())
+    }
+
+    fn disarm(&mut self) {
+        self.armed = false;
+    }
+}
+
+impl Drop for DscpRollback<'_> {
+    fn drop(&mut self) {
+        if self.armed {
+            let _ = self.restore();
+        }
+    }
+}
+
+fn poll_writable_until(
+    socket: &tokio::net::UdpSocket,
+    deadline: &mut Pin<Box<time::Sleep>>,
+    cx: &mut Context<'_>,
+) -> Poll<Result<bool, ClientError>> {
+    match socket.poll_send_ready(cx) {
+        Poll::Ready(Ok(())) => Poll::Ready(Ok(true)),
+        Poll::Ready(Err(error)) => Poll::Ready(Err(ClientError::Socket(error))),
+        Poll::Pending => match deadline.as_mut().poll(cx) {
+            Poll::Ready(()) => Poll::Ready(Ok(false)),
+            Poll::Pending => Poll::Pending,
+        },
+    }
+}
+
+fn poll_readable_until(
+    socket: &tokio::net::UdpSocket,
+    deadline: &mut Pin<Box<time::Sleep>>,
+    cx: &mut Context<'_>,
+) -> Poll<Result<bool, ClientError>> {
+    match socket.poll_recv_ready(cx) {
+        Poll::Ready(Ok(())) => Poll::Ready(Ok(true)),
+        Poll::Ready(Err(error)) => Poll::Ready(Err(ClientError::Socket(error))),
+        Poll::Pending => match deadline.as_mut().poll(cx) {
+            Poll::Ready(()) => Poll::Ready(Ok(false)),
+            Poll::Pending => Poll::Pending,
+        },
+    }
+}

crates/irtt-client/src/auth.rs

@@ -0,0 +1,44 @@
+use std::{fmt, sync::Arc};
+
+/// Shared HMAC key bytes. Debug output never includes the bytes or a fingerprint.
+///
+/// An empty key is still an explicitly configured HMAC key.
+#[derive(Clone, PartialEq, Eq)]
+pub struct HmacKey(Arc<[u8]>);
+
+impl HmacKey {
+    /// Store key bytes without interpreting textual key syntax.
+    pub fn new(bytes: impl Into<Arc<[u8]>>) -> Self {
+        Self(bytes.into())
+    }
+
+    /// Explicitly borrow the key material for authentication.
+    pub fn as_bytes(&self) -> &[u8] {
+        &self.0
+    }
+}
+
+impl fmt::Debug for HmacKey {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str("HmacKey([REDACTED])")
+    }
+}
+
+/// Concrete authentication for a low-level client session.
+#[derive(Clone, Debug, Default, PartialEq, Eq)]
+pub enum Authentication {
+    /// Send and accept packets without HMAC authentication.
+    #[default]
+    Unauthenticated,
+    /// Authenticate packets with this key, including when it is empty.
+    Hmac(HmacKey),
+}
+
+impl Authentication {
+    pub(crate) fn hmac_key(&self) -> Option<&[u8]> {
+        match self {
+            Self::Unauthenticated => None,
+            Self::Hmac(key) => Some(key.as_bytes()),
+        }
+    }
+}

crates/irtt-client/src/client.rs

@@ -4,144 +4,186 @@ use std::{
     time::{Duration, Instant},
 };
 
-#[cfg(test)]
-use irtt_proto::{flags, Params, TimestampFields, PROTOCOL_VERSION};
-
 use crate::{
     config::{ClientConfig, RecvBudget},
     error::ClientError,
     event::{ClientEvent, OpenOutcome},
-    receive::recv_datagram,
-    runtime::{recv_buffer_size, SendProbeResult, SessionRuntime, MAX_OPEN_PACKET_SIZE},
-    socket::{connect_udp_socket, resolve_remote, validate_open_timeouts},
-    socket_options::{apply_dscp_to_socket, clear_dscp_on_socket},
+    receive::{drain_tx_timestamps, recv_datagram, try_enable_tx_timestamping, ReceivedDatagram},
+    session::machine::{
+        recv_buffer_size, OpenDatagramDisposition, PreparedOpenAcceptance, SessionMachine,
+        MAX_OPEN_PACKET_SIZE,
+    },
+    socket::{connect_udp_socket, resolve_remote},
+    socket_options::{apply_traffic_class_to_socket, clear_dscp_on_socket},
     timing::ClientTimestamp,
+    SendProbeError, SendReceipt,
 };
 
-#[cfg(test)]
-use crate::{
-    runtime::{
-        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,
-};
+#[derive(Debug)]
+struct PreparedClientOpen {
+    machine: PreparedOpenAcceptance,
+    recv_buffer_len: Option<usize>,
+    negotiated_traffic_class: Option<u8>,
+    previous_traffic_class: Option<u8>,
+    post_open_recv_timeout: Option<Duration>,
+}
+
+#[derive(Debug)]
+struct PreparedClientOpenFailure {
+    primary: ClientError,
+    machine: PreparedOpenAcceptance,
+}
 
 /// 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 [`ManagedClient`](crate::ManagedClient)
-/// instead.
+/// 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("127.0.0.1:2112", 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: SessionRuntime,
+    runtime: SessionMachine,
     socket: UdpSocket,
     remote: SocketAddr,
     recv_buffer: Vec<u8>,
+    recv_timeout: Option<Duration>,
+    applied_traffic_class: Option<u8>,
+    /// Whether the socket's `SO_TIMESTAMPING` flags carry `TX_SOFTWARE` +
+    /// `OPT_ID` + `OPT_TSONLY`. Always `false` off Linux, without the
+    /// `ancillary` feature, or before the best-effort post-Open upgrade;
+    /// tracked here (adapter-owned capability, not protocol state) so
+    /// unnecessary error-queue drains are skipped once it is known there is
+    /// nothing to drain.
+    tx_timestamping_enabled: bool,
 }
 
 impl Client {
-    /// Resolve the configured server and create a connected UDP socket.
+    /// Resolve the endpoint and create a connected UDP socket.
     ///
     /// This validates local configuration and prepares the open request, but it
     /// does not contact the server. Call [`open`](Self::open) to perform the
     /// IRTT open exchange.
-    pub fn connect(config: ClientConfig) -> Result<Self, ClientError> {
-        validate_open_timeouts(&config.open_timeouts)?;
-        let remote = resolve_remote(&config)?;
-        let runtime = SessionRuntime::new(config.clone(), remote)?;
-        let socket = connect_udp_socket(&config.socket_config, remote)?;
+    ///
+    /// The endpoint accepts a name or address; an omitted port defaults to 2112.
+    /// IPv6 literals may be bracketed or unbracketed with the default port.
+    /// The reusable config contains no endpoint identity.
+    pub fn connect(endpoint: impl AsRef<str>, config: ClientConfig) -> Result<Self, ClientError> {
+        config.open.validate()?;
+        let remote = resolve_remote(endpoint.as_ref(), config.address_family)?;
+        let runtime = SessionMachine::new(config.clone(), remote)?;
+        let socket = connect_udp_socket(&config.socket, remote, config.address_family)?;
 
         Ok(Self {
             runtime,
             socket,
             remote,
             recv_buffer: vec![0_u8; recv_buffer_size(false, None)?],
+            recv_timeout: None,
+            applied_traffic_class: None,
+            tx_timestamping_enabled: false,
         })
     }
 
+    /// Set the blocking receive timeout used outside open attempts.
+    ///
+    /// `None` (the default) lets `recv_once()` block indefinitely. A nonzero
+    /// timeout bounds one logical receive, including retries after EINTR.
+    /// `recv_available()` retains its bounded drain behavior. Open attempts
+    /// use only [`OpenPolicy::timeouts`](crate::OpenPolicy::timeouts) and
+    /// restore this setting on success or failure.
+    ///
+    /// A zero duration is rejected by the socket; the previous setting is
+    /// retained when applying the new timeout fails.
+    pub fn set_recv_timeout(&mut self, timeout: Option<Duration>) -> Result<(), ClientError> {
+        self.socket.set_read_timeout(timeout)?;
+        self.recv_timeout = timeout;
+        Ok(())
+    }
+
     /// Perform the IRTT open exchange.
     ///
     /// 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`].
+    /// Open attempts use [`OpenPolicy::timeouts`](crate::OpenPolicy::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`]. 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
+    /// preserves the original failure. Failed opening never leaves the session
+    /// machine open.
     pub fn open(&mut self) -> Result<OpenOutcome, ClientError> {
-        let outcome = (|| -> Result<OpenOutcome, ClientError> {
-            let packet = self.runtime.open_packet()?;
-            let mut buf = [0_u8; MAX_OPEN_PACKET_SIZE];
-
-            for timeout in &self.runtime.config().open_timeouts {
-                self.socket.set_read_timeout(Some(*timeout))?;
-                self.socket.send(&packet)?;
-
-                match self.socket.recv(&mut buf) {
-                    Ok(size) => {
-                        let reply = self.runtime.decode_open_reply(&buf[..size])?;
-                        let remote = self.remote;
-                        let has_hmac = self.runtime.has_hmac();
-                        let socket = &self.socket;
-                        let recv_buffer = &mut self.recv_buffer;
-
-                        return self.runtime.accept_open_reply(
-                            reply,
-                            ClientTimestamp::now(),
-                            |negotiated| {
-                                let size = recv_buffer_size(has_hmac, Some(negotiated))?;
-                                let negotiated_dscp = u8::try_from(negotiated.params.dscp)
-                                    .map_err(|_| ClientError::InvalidConfig {
-                                        reason: "negotiated dscp must be in range 0..=63"
-                                            .to_owned(),
-                                    })?;
-                                apply_dscp_to_socket(socket, remote, negotiated_dscp)?;
-                                recv_buffer.resize(size, 0);
-                                Ok(())
-                            },
-                        );
-                    }
-                    Err(err)
-                        if matches!(
-                            err.kind(),
-                            io::ErrorKind::WouldBlock | io::ErrorKind::TimedOut
-                        ) => {}
-                    Err(err) => return Err(ClientError::Socket(err)),
-                }
-            }
-
-            Err(ClientError::OpenTimeout)
-        })();
-
-        let restore = self
-            .socket
-            .set_read_timeout(self.runtime.config().socket_config.recv_timeout);
-
-        match (outcome, restore) {
-            (Ok(outcome), Ok(())) => Ok(outcome),
-            (Ok(_), Err(source)) => Err(ClientError::ReadTimeoutRestore { source }),
-            (Err(err), Ok(())) => Err(err),
-            (Err(err), Err(_)) => Err(err),
+        let result = self.open_transaction();
+        if result.is_err() {
+            let _ = self.socket.set_read_timeout(self.recv_timeout);
         }
+        result
     }
 
     /// Send a close request and emit a [`ClientEvent::SessionClosed`] event.
     ///
     /// The close event means the client has sent its close packet and stopped
-    /// tracking the session locally; it is not a server acknowledgement.
+    /// tracking the session locally; it is not a server acknowledgement. If the
+    /// send fails, the negotiated DSCP is restored best-effort and the session
+    /// remains open.
     pub fn close(&mut self) -> Result<Vec<ClientEvent>, ClientError> {
-        let socket = &self.socket;
-        let remote = self.remote;
-        self.runtime.close_with(|packet| {
-            clear_dscp_on_socket(socket, remote)?;
-            socket.send(packet)?;
-            Ok(())
-        })
-    }
+        let prepared = self.runtime.prepare_close()?;
+        let mut events = Vec::new();
 
-    /// Return the monotonic deadline for the next probe send, if another probe
-    /// is scheduled.
-    pub fn next_send_deadline(&self) -> Option<Instant> {
-        self.runtime.next_send_deadline()
+        events
+            .try_reserve(1)
+            .map_err(|source| ClientError::AllocationFailed {
+                operation: "close event result",
+                source,
+            })?;
+        let previous_traffic_class = self.applied_traffic_class;
+        let expected_bytes = prepared.bytes.len();
+
+        self.clear_close_dscp()?;
+        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));
+            }
+        };
+        let sent_at = ClientTimestamp::now();
+
+        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 local timeout used to classify pending probes as lost.
@@ -149,46 +191,179 @@ impl Client {
         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.
-    pub fn send_probe(&mut self) -> Result<Vec<ClientEvent>, ClientError> {
-        self.send_probe_inner(None)
+    /// The negotiated interval and duration do not gate low-level sends.
+    /// A receipt means socket acceptance and infallible session commitment have
+    /// completed. Failures before acceptance return [`SendProbeError::NotCommitted`];
+    /// later validation or TX processing failures preserve the receipt in
+    /// [`SendProbeError::AfterCommit`].
+    pub fn send_probe(&mut self) -> Result<SendReceipt, SendProbeError> {
+        let remote = self.remote;
+        let (runtime, socket) = (&mut self.runtime, &self.socket);
+        let prepared = runtime
+            .prepare_probe()
+            .map_err(SendProbeError::NotCommitted)?;
+        let machine_preflight = runtime
+            .preflight_probe_commit(&prepared)
+            .map_err(SendProbeError::NotCommitted)?;
+        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)
+            .map_err(SendProbeError::NotCommitted)?;
+        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(SendProbeError::NotCommitted(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);
+        let receipt = SendReceipt {
+            seq: sent.seq,
+            remote,
+            sent_at: sent.sent_at,
+            bytes: sent.bytes,
+            send_call,
+        };
+        validate_datagram_length(expected_bytes, bytes).map_err(|source| {
+            SendProbeError::AfterCommit {
+                receipt,
+                source: Box::new(source),
+            }
+        })?;
+        self.drain_tx_timestamps()
+            .map_err(|source| SendProbeError::AfterCommit {
+                receipt,
+                source: Box::new(source),
+            })?;
+
+        Ok(receipt)
     }
 
     /// Receive and classify at most one datagram from the socket.
     ///
     /// Returns an empty event list when the socket read would block or times
     /// out. Malformed or unrelated datagrams are reported as warning events.
+    /// Requires an open session; lifecycle errors are returned before socket I/O.
     pub fn recv_once(&mut self) -> Result<Vec<ClientEvent>, ClientError> {
-        let datagram = match recv_datagram(&self.socket, &mut self.recv_buffer) {
-            Ok(datagram) => datagram,
-            Err(err)
-                if matches!(
-                    err.kind(),
-                    io::ErrorKind::WouldBlock | io::ErrorKind::TimedOut
-                ) =>
-            {
-                return Ok(vec![]);
-            }
-            Err(err) => return Err(ClientError::Socket(err)),
+        self.runtime.ensure_open()?;
+        self.socket.set_read_timeout(self.recv_timeout)?;
+        self.recv_once_inner()
+    }
+
+    fn recv_once_inner(&mut self) -> Result<Vec<ClientEvent>, ClientError> {
+        let Some(datagram) = self.recv_datagram_retrying_interrupted()? else {
+            return Ok(vec![]);
         };
 
-        self.runtime.process_received_echo_packet(
+        // One final bounded drain before processing the reply, so a TX
+        // timestamp that raced the reply is still associated with its probe
+        // before that probe is looked up and possibly removed below.
+        self.drain_tx_timestamps()?;
+
+        let events = self.runtime.process_received_echo_packet(
             &self.recv_buffer[..datagram.len],
             datagram.received_at,
             datagram.meta,
-        )
+        )?;
+        if self.runtime.is_peer_closed() && self.clear_close_dscp().is_ok() {
+            self.applied_traffic_class = None;
+        }
+        Ok(events)
+    }
+
+    /// Receive one datagram, transparently retrying an interrupted syscall
+    /// (`io::ErrorKind::Interrupted`, e.g. `EINTR`) without treating it as a
+    /// genuine socket error, timeout, or empty receive.
+    ///
+    /// One logical receive keeps one timeout budget: when a receive timeout
+    /// is configured, an absolute deadline is computed once here and each
+    /// retry after an interruption restores the socket's remaining time
+    /// against that same deadline, so repeated interruptions cannot extend
+    /// this receive past its configured timeout. An unconfigured timeout
+    /// (`None`) keeps blocking indefinitely after an interruption, matching
+    /// its no-timeout contract. The socket's read timeout is restored to the
+    /// caller-configured value before returning, so a later call in the same
+    /// `recv_available` budget is unaffected by an earlier interruption here.
+    fn recv_datagram_retrying_interrupted(
+        &mut self,
+    ) -> Result<Option<ReceivedDatagram>, ClientError> {
+        let configured_timeout = self.recv_timeout;
+        let deadline = match configured_timeout {
+            Some(timeout) => Some(
+                Instant::now()
+                    .checked_add(timeout)
+                    .ok_or(ClientError::DurationOverflow)?,
+            ),
+            None => None,
+        };
+        let mut timeout_narrowed = false;
+
+        let result = loop {
+            match recv_datagram(&self.socket, &mut self.recv_buffer) {
+                Ok(datagram) => break Ok(Some(datagram)),
+                Err(err)
+                    if matches!(
+                        err.kind(),
+                        io::ErrorKind::WouldBlock | io::ErrorKind::TimedOut
+                    ) =>
+                {
+                    break Ok(None);
+                }
+                Err(err) if err.kind() == io::ErrorKind::Interrupted => {
+                    if let Some(deadline) = deadline {
+                        let Some(remaining) = deadline.checked_duration_since(Instant::now())
+                        else {
+                            break Ok(None);
+                        };
+                        if remaining.is_zero() {
+                            break Ok(None);
+                        }
+                        if let Err(err) = self.socket.set_read_timeout(Some(remaining)) {
+                            break Err(ClientError::Socket(err));
+                        }
+                        timeout_narrowed = true;
+                    }
+                }
+                Err(err) => break Err(ClientError::Socket(err)),
+            }
+        };
+
+        if timeout_narrowed {
+            if let Err(err) = self.socket.set_read_timeout(configured_timeout) {
+                return Err(ClientError::Socket(err));
+            }
+        }
+        result
     }
 
     /// Receive and classify datagrams until a receive produces no events or the
     /// receive budget is exhausted.
+    ///
+    /// Requires an open session; lifecycle errors are returned before socket I/O.
     pub fn recv_available(&mut self, budget: RecvBudget) -> Result<Vec<ClientEvent>, ClientError> {
+        self.runtime.ensure_open()?;
+        self.socket.set_read_timeout(self.recv_timeout)?;
         let mut all_events = Vec::new();
         for _ in 0..budget.max_packets {
-            let events = self.recv_once()?;
+            let events = self.recv_once_inner()?;
             if events.is_empty() {
                 break;
             }
@@ -213,16 +388,25 @@ impl Client {
     ///
     /// `now` is monotonic time only; wall-clock time is not used for timeout expiry.
     pub fn poll_timeouts_at(&mut self, now: Instant) -> Result<Vec<ClientEvent>, ClientError> {
+        self.drain_tx_timestamps()?;
         self.runtime.poll_timeouts_at(now)
     }
 
-    /// Return whether the current run has completed.
+    /// Accepted semantics and exact peer parameters of the currently live session.
     ///
-    /// 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_run_complete()
+    /// Returns `None` before Open, after Close, and after no-test completion.
+    pub fn negotiation(&self) -> Option<&crate::NegotiationResult> {
+        self.runtime.negotiation()
+    }
+
+    /// 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.
@@ -235,39 +419,214 @@ impl Client {
         self.runtime.is_peer_closed()
     }
 
-    pub(crate) fn has_timed_out_metadata(&self) -> bool {
-        self.runtime.has_timed_out_metadata()
+    fn open_transaction(&mut self) -> Result<OpenOutcome, ClientError> {
+        let request = self.runtime.prepare_open_request()?;
+        let mut buf = [0_u8; MAX_OPEN_PACKET_SIZE];
+        let attempt_count = self.runtime.config().open.timeouts.len();
+
+        for attempt in 0..attempt_count {
+            let timeout = self.runtime.config().open.timeouts[attempt];
+            let deadline = Instant::now()
+                .checked_add(timeout)
+                .ok_or(ClientError::DurationOverflow)?;
+            self.socket.set_read_timeout(Some(timeout))?;
+            self.socket.send(&request.bytes)?;
+
+            loop {
+                let now = Instant::now();
+                let Some(remaining) = deadline.checked_duration_since(now) else {
+                    break;
+                };
+                if remaining.is_zero() {
+                    break;
+                }
+                self.socket.set_read_timeout(Some(remaining))?;
+
+                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
+                    // merely interrupted and carries no timing information of
+                    // its own. Both retry through the same loop, which
+                    // recomputes `remaining` and re-applies it as the read
+                    // timeout on every iteration — so an interruption resumes
+                    // within this same absolute deadline rather than
+                    // resetting or extending it.
+                    Err(err)
+                        if matches!(
+                            err.kind(),
+                            io::ErrorKind::WouldBlock
+                                | io::ErrorKind::TimedOut
+                                | io::ErrorKind::Interrupted
+                        ) =>
+                    {
+                        if Instant::now() >= deadline {
+                            break;
+                        }
+                        continue;
+                    }
+                    Err(err) => return Err(ClientError::Socket(err)),
+                };
+                if datagram.received_at.mono > deadline {
+                    break;
+                }
+
+                let reply = match self.runtime.inspect_open_datagram(&buf[..datagram.len])? {
+                    OpenDatagramDisposition::Ignore => continue,
+                    OpenDatagramDisposition::Trusted(reply) => reply,
+                };
+                let machine = match self
+                    .runtime
+                    .prepare_open_acceptance(reply, datagram.received_at)
+                {
+                    Ok(machine) => machine,
+                    Err(failure) => {
+                        self.send_cleanup_close_best_effort(failure.cleanup_close.as_deref());
+                        return Err(failure.primary);
+                    }
+                };
+                let prepared = match self.prepare_client_open(machine) {
+                    Ok(prepared) => prepared,
+                    Err(failure) => {
+                        self.send_cleanup_close_best_effort(failure.machine.cleanup_close_packet());
+                        return Err(failure.primary);
+                    }
+                };
+                return self.apply_prepared_open(prepared);
+            }
+        }
+
+        Err(ClientError::OpenTimeout)
     }
 
-    pub(crate) fn packets_sent(&self) -> u64 {
-        self.runtime.packets_sent()
-    }
+    fn prepare_client_open(
+        &self,
+        machine: PreparedOpenAcceptance,
+    ) -> Result<PreparedClientOpen, Box<PreparedClientOpenFailure>> {
+        let Some(negotiated) = machine.normal_negotiated() else {
+            return Ok(PreparedClientOpen {
+                machine,
+                recv_buffer_len: None,
+                negotiated_traffic_class: None,
+                previous_traffic_class: self.applied_traffic_class,
+                post_open_recv_timeout: self.recv_timeout,
+            });
+        };
+        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 })),
+        };
 
-    fn send_probe_inner(
-        &mut self,
-        override_ts: Option<ClientTimestamp>,
-    ) -> Result<Vec<ClientEvent>, ClientError> {
-        let socket = &self.socket;
-        self.runtime.send_probe_with(override_ts, |packet| {
-            let sent_at = override_ts.unwrap_or_else(ClientTimestamp::now);
-            let send_call_start = Instant::now();
-            let bytes = socket.send(packet)?;
-            let send_call = send_call_start.elapsed();
-            Ok(SendProbeResult {
-                sent_at,
-                bytes,
-                send_call,
-            })
+        let negotiated_traffic_class = negotiated.accepted.dscp << 2;
+        Ok(PreparedClientOpen {
+            machine,
+            recv_buffer_len: Some(recv_buffer_len),
+            negotiated_traffic_class: Some(negotiated_traffic_class),
+            previous_traffic_class: self.applied_traffic_class,
+            post_open_recv_timeout: self.recv_timeout,
         })
     }
-}
 
-#[cfg(test)]
-impl Client {
-    fn send_probe_at(&mut self, ts: ClientTimestamp) -> Result<Vec<ClientEvent>, ClientError> {
-        self.send_probe_inner(Some(ts))
+    fn apply_prepared_open(
+        &mut self,
+        prepared: PreparedClientOpen,
+    ) -> Result<OpenOutcome, ClientError> {
+        let PreparedClientOpen {
+            machine,
+            recv_buffer_len,
+            negotiated_traffic_class,
+            previous_traffic_class,
+            post_open_recv_timeout,
+        } = prepared;
+
+        if let (Some(recv_buffer_len), Some(negotiated_traffic_class)) =
+            (recv_buffer_len, negotiated_traffic_class)
+        {
+            let previous_len = self.recv_buffer.len();
+            let additional = recv_buffer_len.saturating_sub(previous_len);
+            if let Err(source) = self.recv_buffer.try_reserve(additional) {
+                self.send_cleanup_close_best_effort(machine.cleanup_close_packet());
+                return Err(ClientError::AllocationFailed {
+                    operation: "negotiated receive buffer",
+                    source,
+                });
+            }
+            self.recv_buffer.resize(recv_buffer_len, 0);
+
+            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.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);
+                self.send_cleanup_close_best_effort(machine.cleanup_close_packet());
+                return Err(primary);
+            }
+
+            let outcome = self.runtime.commit_open(machine);
+
+            self.applied_traffic_class = Some(negotiated_traffic_class);
+            self.tx_timestamping_enabled = try_enable_tx_timestamping(&self.socket);
+            Ok(outcome)
+        } else {
+            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.applied_traffic_class = None;
+            self.tx_timestamping_enabled = try_enable_tx_timestamping(&self.socket);
+            Ok(outcome)
+        }
+    }
+
+    /// Best-effort, bounded, nonblocking drain of the socket's
+    /// `MSG_ERRQUEUE`. A no-op unless [`Self::apply_prepared_open`]
+    /// successfully upgraded the socket to TX timestamping. Any TX
+    /// timestamp found is handed to the session machine to attach to its
+    /// matching probe; a genuine socket/network error found on the queue is
+    /// surfaced through the normal socket-error path.
+    fn drain_tx_timestamps(&mut self) -> Result<(), ClientError> {
+        if !self.tx_timestamping_enabled {
+            return Ok(());
+        }
+        let runtime = &mut self.runtime;
+        drain_tx_timestamps(&self.socket, |id, timestamp| {
+            runtime.record_kernel_tx_timestamp(id, timestamp);
+        })
+        .map_err(ClientError::Socket)
+    }
+
+    fn restore_dscp_best_effort(&self, previous_traffic_class: Option<u8>) {
+        let _ = match previous_traffic_class {
+            Some(traffic_class) => {
+                apply_traffic_class_to_socket(&self.socket, self.remote, traffic_class)
+            }
+            None => clear_dscp_on_socket(&self.socket, self.remote),
+        };
+    }
+
+    fn clear_close_dscp(&self) -> Result<(), ClientError> {
+        clear_dscp_on_socket(&self.socket, self.remote)
+    }
+
+    fn send_cleanup_close_best_effort(&self, packet: Option<&[u8]>) {
+        if let Some(packet) = packet {
+            let _ = self.socket.send(packet);
+        }
     }
 }
 
-#[cfg(test)]
-mod tests;
+pub(crate) fn validate_datagram_length(expected: usize, actual: usize) -> Result<(), ClientError> {
+    if actual == expected {
+        Ok(())
+    } else {
+        Err(ClientError::DatagramLengthMismatch { expected, actual })
+    }
+}

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

@@ -1,147 +0,0 @@
-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 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());
-    client.close().unwrap();
-    assert!(matches!(client.open(), Err(ClientError::AlreadyClosed)));
-    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 events = client.close().unwrap();
-    assert_eq!(events.len(), 1);
-    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 send_probe_fails_after_close() {
-    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();
-        socket
-            .set_read_timeout(Some(Duration::from_secs(2)))
-            .unwrap();
-        loop {
-            let mut buf = [0_u8; 512];
-            match socket.recv_from(&mut buf) {
-                Ok((size, _)) => {
-                    tx.send(buf[..size].to_vec()).unwrap();
-                }
-                Err(_) => break,
-            }
-        }
-    });
-    let mut client = Client::connect(default_test_config(server.addr)).unwrap();
-    assert_open_started(client.open().unwrap());
-    client.close().unwrap();
-    assert!(matches!(
-        client.send_probe(),
-        Err(ClientError::AlreadyClosed)
-    ));
-    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!(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 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();
-}

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

@@ -1,186 +0,0 @@
-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, 46, "config DSCP codepoint must not be shifted");
-    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, 63);
-}
-
-#[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() {
-    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 = [
-        (
-            "oversized UDP payload",
-            ClientConfig {
-                length: MAX_UDP_PAYLOAD_LENGTH + 1,
-                ..ClientConfig::default()
-            },
-            "packet length",
-        ),
-        (
-            "zero finite duration",
-            ClientConfig {
-                duration: Some(Duration::ZERO),
-                ..ClientConfig::default()
-            },
-            "duration must be greater than zero; use None for continuous mode",
-        ),
-        (
-            "zero interval",
-            ClientConfig {
-                interval: Duration::ZERO,
-                ..ClientConfig::default()
-            },
-            "interval must be greater than zero",
-        ),
-        (
-            "duration nanosecond overflow",
-            ClientConfig {
-                duration: Some(too_large),
-                ..ClientConfig::default()
-            },
-            "duration is too large to encode as nanoseconds",
-        ),
-        (
-            "interval nanosecond overflow",
-            ClientConfig {
-                interval: too_large,
-                ..ClientConfig::default()
-            },
-            "interval is too large to encode as nanoseconds",
-        ),
-        (
-            "invalid DSCP codepoint",
-            ClientConfig {
-                dscp: 64,
-                ..ClientConfig::default()
-            },
-            "dscp",
-        ),
-        (
-            "empty server fill",
-            ClientConfig {
-                server_fill: Some("".to_owned()),
-                ..ClientConfig::default()
-            },
-            "server_fill",
-        ),
-        (
-            "oversized server fill",
-            ClientConfig {
-                server_fill: Some("0123456789abcdef0123456789abcdefx".to_owned()),
-                ..ClientConfig::default()
-            },
-            "server_fill",
-        ),
-    ];
-
-    for (name, config, expected_reason) in cases {
-        assert!(
-            matches!(
-                params_from_config(&config),
-                Err(ClientError::InvalidConfig { reason }) if reason.contains(expected_reason)
-            ),
-            "{name} should fail with InvalidConfig containing {expected_reason:?}"
-        );
-    }
-}
-
-#[test]
-fn minimum_open_timeout_under_200ms_is_rejected() {
-    let config = ClientConfig {
-        open_timeouts: vec![Duration::from_millis(199)],
-        ..ClientConfig::default()
-    };
-    assert!(matches!(
-        Client::connect(config),
-        Err(ClientError::OpenTimeoutTooSmall { .. })
-    ));
-}
-
-#[test]
-fn empty_open_timeouts_is_rejected() {
-    let config = ClientConfig {
-        open_timeouts: vec![],
-        ..ClientConfig::default()
-    };
-    assert!(matches!(
-        Client::connect(config),
-        Err(ClientError::NoOpenTimeouts)
-    ));
-}

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

@@ -1,75 +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_dscp_after_open_and_close_clears_it() {
-    let mut params = default_params();
-    params.dscp = 46;
-    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_dscp_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();
-}

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

@@ -1,184 +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_hmac(&key, &request, HMAC_OFFSET).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_rejects_missing_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);
-    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();
-    });
-    config.server_addr = server.addr.to_string();
-    let mut client = Client::connect(config).unwrap();
-    assert!(matches!(
-        client.open(),
-        Err(ClientError::Protocol(
-            irtt_proto::ProtoError::HmacPresenceMismatch
-        ))
-    ));
-    server.join();
-}
-
-#[test]
-fn hmac_open_rejects_bad_hmac() {
-    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);
-    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, Some(&wrong_key));
-        socket.send_to(&reply, peer).unwrap();
-    });
-    config.server_addr = server.addr.to_string();
-    let mut client = Client::connect(config).unwrap();
-    assert!(matches!(
-        client.open(),
-        Err(ClientError::Protocol(irtt_proto::ProtoError::BadHmac))
-    ));
-    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_hmac(&key, close, HMAC_OFFSET).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(TOKEN, seq, &params, &ts, Some(&wrong_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(30));
-    let events = client.recv_once().unwrap();
-    assert_eq!(events.len(), 1);
-    assert!(matches!(&events[0], ClientEvent::Warning { .. }));
-    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_hmac(&server_key, &buf[..size], HMAC_OFFSET).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_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

@@ -1,268 +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();
-    let mut returned = requested.clone();
-    returned.dscp = 0;
-    assert_eq!(
-        rejection_reason(&requested, &returned, NegotiationPolicy::Strict),
-        NegotiationRestriction::DscpChanged {
-            requested: requested.dscp,
-            negotiated: returned.dscp,
-        }
-        .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::default();
-    let requested = params_from_config(&config).unwrap();
-
-    for dscp in [-1, 64] {
-        let mut returned = requested.clone();
-        returned.dscp = dscp;
-        assert_eq!(
-            rejection_reason(&requested, &returned, NegotiationPolicy::Loose),
-            "dscp must be in range 0..=63"
-        );
-    }
-}
-
-#[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/no_test.rs

@@ -1,112 +0,0 @@
-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();
-    let negotiated = assert_no_test_completed(client.open().unwrap());
-    assert_eq!(negotiated.params, params);
-    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 server = open_success_server(params);
-    config.server_addr = server.addr.to_string();
-    let mut client = Client::connect(config).unwrap();
-    assert!(matches!(
-        client.open(),
-        Err(ClientError::UnexpectedNoTestReply)
-    ));
-    server.join();
-}
-
-#[test]
-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 server = no_test_server(params, TOKEN);
-    config.server_addr = server.addr.to_string();
-    let mut client = Client::connect(config).unwrap();
-    assert!(matches!(
-        client.open(),
-        Err(ClientError::NonZeroNoTestToken { token: TOKEN })
-    ));
-    server.join();
-}
-
-#[test]
-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();
-    params.dscp = 1;
-    let server = no_test_server(params, 0);
-    config.server_addr = server.addr.to_string();
-    let mut client = Client::connect(config).unwrap();
-    assert!(matches!(
-        client.open(),
-        Err(ClientError::NegotiationRejected { .. })
-    ));
-    server.join();
-}
-
-#[test]
-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 mut params = requested.clone();
-    params.duration_ns /= 2;
-    let server = no_test_server(params.clone(), 0);
-    config.server_addr = server.addr.to_string();
-    let mut client = Client::connect(config).unwrap();
-    let negotiated = assert_no_test_completed(client.open().unwrap());
-    assert_eq!(negotiated.params, params);
-    assert_eq!(
-        negotiated.restrictions,
-        vec![crate::NegotiationRestriction::DurationReduced {
-            requested_ns: requested.duration_ns,
-            negotiated_ns: params.duration_ns,
-        }]
-    );
-    server.join();
-}
-
-#[test]
-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 server = no_test_server(params, 0);
-    config.server_addr = server.addr.to_string();
-    let mut client = Client::connect(config).unwrap();
-    assert_no_test_completed(client.open().unwrap());
-    assert!(matches!(
-        client.send_probe(),
-        Err(ClientError::AlreadyCompleted)
-    ));
-    server.join();
-}
-
-#[test]
-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 server = no_test_server(params, 0);
-    config.server_addr = server.addr.to_string();
-    let mut client = Client::connect(config).unwrap();
-    assert_no_test_completed(client.open().unwrap());
-    assert!(matches!(client.open(), Err(ClientError::AlreadyCompleted)));
-    server.join();
-}

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

@@ -1,87 +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);
-    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_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)],
-        ..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 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, .. })
-    ));
-    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)));
-    server.join();
-}

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

@@ -1,121 +0,0 @@
-use super::*;
-
-#[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_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 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(now0).is_ok());
-
-    let now1 = ClientTimestamp {
-        mono: start + interval,
-        wall: SystemTime::now(),
-    };
-    assert!(client.send_probe_at(now1).is_ok());
-
-    let now2 = ClientTimestamp {
-        mono: start + Duration::from_secs(1),
-        wall: SystemTime::now(),
-    };
-    let events = client.send_probe_at(now2).unwrap();
-    assert!(events.is_empty());
-    assert!(client.next_send_deadline().is_none());
-
-    client.close().unwrap();
-    server.join();
-}
-
-#[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/reply_decode.rs

@@ -1,140 +0,0 @@
-use super::*;
-
-#[test]
-fn recv_once_returns_empty_on_timeout() {
-    let params = default_params();
-    let server = open_success_server(params);
-    let config = ClientConfig {
-        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_open_started(client.open().unwrap());
-    let events = client.recv_once().unwrap();
-    assert!(events.is_empty());
-    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();
-    let server_params = params.clone();
-    let server = start_fake_server(move |socket, tx| {
-        let (_, peer) = recv_request(&socket, &tx);
-        let reply = open_reply(FLAG_OPEN | FLAG_REPLY, TOKEN, &server_params, None);
-        socket.send_to(&reply, peer).unwrap();
-
-        let mut seqs = Vec::new();
-        for _ in 0..2 {
-            let (packet, _) = recv_request(&socket, &tx);
-            seqs.push(u32::from_le_bytes(packet[12..16].try_into().unwrap()));
-        }
-
-        let mut longer = echo_reply_packet(
-            TOKEN,
-            seqs[0],
-            &server_params,
-            &TimestampFields::default(),
-            None,
-        );
-        longer.extend_from_slice(b"trailing bytes");
-        socket.send_to(&longer, peer).unwrap();
-
-        let shorter = echo_reply_packet(
-            TOKEN,
-            seqs[1],
-            &server_params,
-            &TimestampFields::default(),
-            None,
-        );
-        socket.send_to(&shorter, peer).unwrap();
-    });
-    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();
-    client.send_probe().unwrap();
-    thread::sleep(Duration::from_millis(50));
-
-    let _ = client.recv_once().unwrap();
-    let events = client.recv_once().unwrap();
-    assert_eq!(events.len(), 1);
-    match &events[0] {
-        ClientEvent::EchoReply { seq, bytes, .. } => {
-            assert_eq!(*seq, 1);
-            assert_eq!(*bytes, echo_packet_len(false, &params));
-        }
-        other => panic!("expected EchoReply after shorter datagram, got {other:?}"),
-    }
-    server.join();
-}

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

@@ -1,157 +0,0 @@
-use super::*;
-
-#[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, &received_at, &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, &received_at, &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, &received_at, &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, &received_at, &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

@@ -1,10 +1,12 @@
 use std::{net::SocketAddr, time::Duration};
 
+use crate::{Authentication, ClientError};
+
 /// Protocol compatibility bound for a requested `server_fill` value, in UTF-8
 /// bytes.
 ///
 /// This is the maximum encoded server-fill string accepted by this client and
-/// protocol decoder. [`ClientConfig::server_fill`] enforces the same bound
+/// protocol decoder. [`SessionRequest::server_fill`] enforces the same bound
 /// before opening a session.
 pub use irtt_proto::MAX_SERVER_FILL_BYTES;
 use irtt_proto::{Clock, ReceivedStats, StampAt};
@@ -12,8 +14,10 @@ use irtt_proto::{Clock, ReceivedStats, StampAt};
 pub(crate) const DEFAULT_PORT: u16 = 2112;
 /// Largest valid DSCP codepoint accepted by client configuration.
 ///
-/// DSCP is a six-bit value in the range `0..=63`. The client maps it into the
-/// socket traffic-class field when configuring packet priority.
+/// DSCP is a six-bit value in the range `0..=63`. The client shifts it left
+/// by two bits into the raw IP TOS / Traffic Class byte carried by
+/// [`irtt_proto::Params::dscp`] and applied to the socket during the active
+/// test phase.
 pub const MAX_DSCP_CODEPOINT: u8 = 63;
 /// Largest IPv4 TTL or IPv6 hop-limit value accepted by client configuration.
 ///
@@ -24,7 +28,7 @@ pub const MAX_TTL: u32 = 255;
 /// Largest UDP payload length accepted by client configuration, in bytes.
 ///
 /// This is the maximum UDP payload size excluding IP and UDP headers. It caps
-/// [`ClientConfig::length`] before protocol packets are encoded or sent.
+/// [`SessionRequest::length`] before protocol packets are encoded or sent.
 pub const MAX_UDP_PAYLOAD_LENGTH: u32 = 65_507;
 pub(crate) const DEFAULT_DURATION: Duration = Duration::from_secs(3);
 pub(crate) const DEFAULT_INTERVAL: Duration = Duration::from_secs(1);
@@ -43,68 +47,51 @@ pub(crate) const DEFAULT_MAX_PENDING: usize = 4096;
 /// This type describes both the protocol parameters sent in the IRTT open
 /// 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).
+/// through [`NegotiationResult`](crate::NegotiationResult).
+///
+/// # 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, OpenPolicy, SessionRequest};
+///
+/// let config = ClientConfig {
+///     request: SessionRequest {
+///         duration: Some(Duration::from_secs(10)),
+///         interval: Duration::from_millis(250),
+///         length: 1200,
+///         ..SessionRequest::default()
+///     },
+///     open: OpenPolicy {
+///         negotiation: NegotiationPolicy::Loose,
+///         ..OpenPolicy::default()
+///     },
+///     ..ClientConfig::default()
+/// };
+///
+/// assert_eq!(config.request.duration, Some(Duration::from_secs(10)));
+/// assert_eq!(config.request.interval, Duration::from_millis(250));
+/// assert_eq!(config.request.length, 1200);
+/// ```
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub struct ClientConfig {
-    /// Remote server name or address.
+    /// Remote address families allowed during resolution and socket creation.
+    pub address_family: AddressFamily,
+    /// Local UDP socket properties.
+    pub socket: SocketConfig,
+    /// Protocol and session values requested from the server.
+    pub request: SessionRequest,
+    /// Open retry timeouts and negotiation policy.
+    pub open: OpenPolicy,
+    /// Concrete authentication for open, echo, and close packets.
     ///
-    /// If no port is present, the default IRTT port 2112 is used. IPv6
-    /// literals may be supplied either bracketed or unbracketed when the
-    /// default port should be used.
-    pub server_addr: String,
-    /// Requested run duration.
-    ///
-    /// `Some(duration)` requests a finite test and must be greater than zero.
-    /// `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.
-    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.
-    pub interval: Duration,
-    /// Requested echo packet payload length, in bytes.
-    ///
-    /// The value must fit within the UDP payload limit after protocol overhead.
-    /// A server may reduce the requested length during negotiation.
-    pub length: u32,
-    /// Requested server receive-statistics fields in echo replies.
-    pub received_stats: ReceivedStats,
-    /// Requested timestamp placement in echo replies.
-    pub stamp_at: StampAt,
-    /// Requested server clock sources for timestamp fields.
-    pub clock: Clock,
-    /// Requested DSCP codepoint.
-    ///
-    /// This is the six-bit DSCP value, not the full traffic-class byte, and
-    /// must be less than or equal to [`MAX_DSCP_CODEPOINT`].
-    pub dscp: u8,
-    /// Optional HMAC key used to authenticate IRTT packets.
-    ///
-    /// When present, open, echo, and close packets are encoded and decoded with
-    /// HMAC authentication. The peer must be configured with the same key.
-    pub hmac_key: Option<Vec<u8>>,
-    /// Optional server payload fill request.
-    ///
-    /// `None` leaves server fill behavior unspecified. `Some(value)` requests
-    /// a non-empty server fill mode/value and must not exceed
-    /// [`MAX_SERVER_FILL_BYTES`] bytes when UTF-8 encoded.
-    pub server_fill: Option<String>,
-    /// Per-attempt receive timeouts used while opening the session.
-    ///
-    /// The client sends an open request for each entry until a valid open reply
-    /// is received. The list must not be empty, and each timeout must be at
-    /// least 200 ms.
-    pub open_timeouts: Vec<Duration>,
-    /// Whether opening the session should start a probe test or perform a
-    /// negotiation-only no-test exchange.
-    pub run_mode: RunMode,
-    /// Policy for server changes to negotiable protocol parameters.
-    pub negotiation_policy: NegotiationPolicy,
-    /// Local UDP socket configuration.
-    pub socket_config: SocketConfig,
+    /// HMAC peers must use the same key. An empty HMAC key remains authenticated.
+    pub auth: Authentication,
     /// Time after sending a probe before the client reports it as lost.
     ///
     /// This timeout is local client behavior; it is not negotiated with the
@@ -118,34 +105,88 @@ pub struct ClientConfig {
     pub max_pending_probes: usize,
 }
 
-/// Authentication settings used by client sessions.
-///
-/// `ClientConfig` keeps its existing top-level HMAC field for source
-/// compatibility. Managed multi-target callers can use this smaller type for
-/// per-target auth overrides without carrying a full independent
-/// [`ClientConfig`].
-#[derive(Debug, Clone, PartialEq, Eq, Default)]
-pub struct ClientAuthConfig {
-    /// Optional HMAC key used to authenticate IRTT packets.
-    pub hmac_key: Option<Vec<u8>>,
-}
-
-impl From<Option<Vec<u8>>> for ClientAuthConfig {
-    fn from(hmac_key: Option<Vec<u8>>) -> Self {
-        Self { hmac_key }
-    }
-}
-
-impl From<ClientAuthConfig> for Option<Vec<u8>> {
-    fn from(auth: ClientAuthConfig) -> Self {
-        auth.hmac_key
-    }
-}
-
 impl Default for ClientConfig {
     fn default() -> Self {
         Self {
-            server_addr: format!("127.0.0.1:{DEFAULT_PORT}"),
+            address_family: AddressFamily::default(),
+            socket: SocketConfig::default(),
+            request: SessionRequest::default(),
+            open: OpenPolicy::default(),
+            auth: Authentication::Unauthenticated,
+            probe_timeout: DEFAULT_PROBE_TIMEOUT,
+            max_pending_probes: DEFAULT_MAX_PENDING,
+        }
+    }
+}
+
+/// Allowed remote address families. IPv6-only selection also sets IPV6_V6ONLY.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
+pub enum AddressFamily {
+    /// Accept IPv4 and IPv6 addresses.
+    #[default]
+    Any,
+    /// Accept only IPv4 addresses.
+    Ipv4,
+    /// Accept only IPv6 addresses and use IPv6-only sockets.
+    Ipv6,
+}
+
+/// Requested IRTT protocol and session semantics, reusable across endpoints.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct SessionRequest {
+    /// Requested run duration.
+    ///
+    /// `Some(duration)` requests a finite test and must be greater than zero.
+    /// `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.
+    ///
+    /// The value must fit within the UDP payload limit after protocol overhead.
+    /// A server may reduce the requested length during negotiation.
+    pub length: u32,
+    /// Requested server receive-statistics fields in echo replies.
+    pub received_stats: ReceivedStats,
+    /// Requested timestamp placement in echo replies.
+    pub stamp_at: StampAt,
+    /// Requested server clock sources for timestamp fields.
+    ///
+    /// [`Clock::Unspecified`] is the wire default meaning "no clock tag was
+    /// sent" and is not a client mode; opening a session with it is rejected.
+    /// Request [`Clock::Wall`], [`Clock::Monotonic`], or [`Clock::Both`].
+    pub clock: Clock,
+    /// Requested DSCP codepoint.
+    ///
+    /// This is the six-bit DSCP value, not the full traffic-class byte, and
+    /// must be less than or equal to [`MAX_DSCP_CODEPOINT`].
+    pub dscp: u8,
+    /// Optional server payload fill request.
+    ///
+    /// `None` leaves server fill behavior unspecified. `Some(value)` requests
+    /// a non-empty server fill mode/value and must not exceed
+    /// [`MAX_SERVER_FILL_BYTES`] bytes when UTF-8 encoded.
+    pub server_fill: Option<String>,
+    /// Whether opening the session should start a probe test or perform a
+    /// negotiation-only no-test exchange.
+    pub run_mode: RunMode,
+}
+
+impl Default for SessionRequest {
+    fn default() -> Self {
+        Self {
             duration: Some(DEFAULT_DURATION),
             interval: DEFAULT_INTERVAL,
             length: 0,
@@ -153,23 +194,78 @@ impl Default for ClientConfig {
             stamp_at: StampAt::Both,
             clock: Clock::Both,
             dscp: 0,
-            hmac_key: None,
             server_fill: None,
-            open_timeouts: DEFAULT_OPEN_TIMEOUTS.to_vec(),
             run_mode: RunMode::Normal,
-            negotiation_policy: NegotiationPolicy::Strict,
-            socket_config: SocketConfig::default(),
-            probe_timeout: DEFAULT_PROBE_TIMEOUT,
-            max_pending_probes: DEFAULT_MAX_PENDING,
+        }
+    }
+}
+
+/// Opening behavior shared by blocking, async, and managed clients.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct OpenPolicy {
+    /// Per-attempt receive timeouts used while opening the session.
+    ///
+    /// The client sends an open request for each entry until a valid open reply
+    /// is received. The list must not be empty, and each timeout must be at
+    /// least 200 ms.
+    pub timeouts: Vec<Duration>,
+    /// Policy for server changes to negotiable protocol parameters.
+    pub negotiation: NegotiationPolicy,
+}
+
+impl OpenPolicy {
+    pub(crate) fn validate(&self) -> Result<(), ClientError> {
+        if self.timeouts.is_empty() {
+            return Err(ClientError::NoOpenTimeouts);
+        }
+        for timeout in &self.timeouts {
+            if *timeout < MIN_OPEN_TIMEOUT {
+                return Err(ClientError::OpenTimeoutTooSmall {
+                    timeout: *timeout,
+                    minimum: MIN_OPEN_TIMEOUT,
+                });
+            }
+        }
+        Ok(())
+    }
+}
+
+impl Default for OpenPolicy {
+    fn default() -> Self {
+        Self {
+            timeouts: DEFAULT_OPEN_TIMEOUTS.to_vec(),
+            negotiation: NegotiationPolicy::Strict,
         }
     }
 }
 
 /// Local UDP socket options used by [`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.
+/// These settings affect how the client binds and sends 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::{AddressFamily, ClientConfig, SocketConfig};
+///
+/// let config = ClientConfig {
+///     address_family: AddressFamily::Ipv4,
+///     socket: SocketConfig {
+///         bind_addr: Some(SocketAddr::from((Ipv4Addr::UNSPECIFIED, 0))),
+///         ttl: Some(32),
+///         ..SocketConfig::default()
+///     },
+///     ..ClientConfig::default()
+/// };
+///
+/// assert_eq!(config.socket.ttl, Some(32));
+/// assert_eq!(config.address_family, AddressFamily::Ipv4);
+/// ```
 #[derive(Debug, Clone, PartialEq, Eq, Default)]
 pub struct SocketConfig {
     /// Local address to bind before connecting the UDP socket.
@@ -177,23 +273,21 @@ 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
     /// platform socket option range; [`MAX_TTL`] is the public configuration
     /// bound used by this crate.
     pub ttl: Option<u32>,
-    /// Restrict name resolution to IPv4 addresses.
-    pub ipv4_only: bool,
-    /// Restrict name resolution to IPv6 addresses and set IPV6_V6ONLY for IPv6
-    /// sockets.
-    pub ipv6_only: bool,
-    /// Socket read timeout used after the session is open.
-    ///
-    /// `None` leaves reads blocking for APIs that perform a single receive.
-    /// Managed sessions may replace `None` or long timeouts with a short
-    /// timeout so cooperative cancellation can be observed promptly.
-    pub recv_timeout: Option<Duration>,
 }
 
 /// How strictly to handle server-side negotiation restrictions.
@@ -203,14 +297,15 @@ pub enum NegotiationPolicy {
     /// than requested.
     Strict,
     /// Accept documented server restrictions and report them in
-    /// [`NegotiatedParams`](crate::NegotiatedParams).
+    /// [`NegotiationResult`](crate::NegotiationResult).
     Loose,
 }
 
 /// 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/error.rs

@@ -1,4 +1,4 @@
-use std::{io, time::Duration};
+use std::{collections::TryReserveError, io, time::Duration};
 
 use thiserror::Error;
 
@@ -12,6 +12,10 @@ use thiserror::Error;
 #[derive(Debug, Error)]
 #[non_exhaustive]
 pub enum ClientError {
+    /// A Tokio-backed client operation was polled without a current runtime.
+    #[cfg(feature = "tokio")]
+    #[error("Tokio AsyncClient requires a current Tokio runtime")]
+    NoTokioRuntime,
     /// The configured server address could not be resolved to a socket address.
     ///
     /// Check the host, port, address-family restrictions, and name service
@@ -38,8 +42,8 @@ pub enum ClientError {
     },
     /// Restoring the configured read timeout after open negotiation failed.
     ///
-    /// The session may have opened successfully, but the socket could not be
-    /// returned to the caller's requested receive-timeout behavior.
+    /// The prepared session was not committed, and the client remains
+    /// connected rather than partially open.
     #[error("failed to restore configured socket read timeout after open negotiation: {source}")]
     ReadTimeoutRestore { source: io::Error },
     /// A packet failed IRTT protocol parsing or authentication.
@@ -146,32 +150,40 @@ pub enum ClientError {
     /// sending again.
     #[error("pending probe limit exceeded ({limit})")]
     PendingLimitExceeded { limit: usize },
+    /// A wrapping wire sequence is still represented by an in-flight probe.
+    ///
+    /// The existing probe must be replied to or timed out before that sequence
+    /// can be reused.
+    #[error("wire sequence {seq} is still pending")]
+    PendingSequenceCollision { seq: u32 },
+    /// A prepared probe no longer matches the session's next wire sequence.
+    ///
+    /// Prepare the probe again after any intervening successful send.
+    #[error(
+        "prepared probe sequence {prepared_seq} is stale; next wire sequence is {next_wire_seq}"
+    )]
+    StalePreparedProbe {
+        prepared_seq: u32,
+        next_wire_seq: u32,
+    },
+    /// Reserving memory required by an operation failed before any datagram was
+    /// sent or logical protocol state was changed.
+    #[error("failed to reserve memory for {operation}: {source}")]
+    AllocationFailed {
+        operation: &'static str,
+        #[source]
+        source: TryReserveError,
+    },
+    /// UDP reported successful acceptance of a datagram with an unexpected
+    /// byte count.
+    ///
+    /// The send is committed locally before this transport invariant failure
+    /// is returned because the kernel reported success.
+    #[error("UDP accepted {actual} bytes for a {expected}-byte datagram")]
+    DatagramLengthMismatch { expected: usize, actual: usize },
     /// Client configuration failed validation before the requested operation.
     ///
     /// The reported reason names a value that must be changed before retrying.
     #[error("invalid configuration: {reason}")]
     InvalidConfig { reason: String },
-    /// A managed-session worker thread panicked before producing an outcome.
-    ///
-    /// This is a runtime failure from joining the managed session, not a
-    /// protocol response from the server.
-    #[error("managed client worker thread panicked")]
-    WorkerPanicked,
-}
-
-/// Failure reported while setting up or receiving from an event subscription.
-///
-/// Zero-capacity subscriber queues are rejected when subscriptions are created.
-/// Once a subscription exists, this error type reports delivery failures observed
-/// by [`EventSubscription`](crate::EventSubscription).
-#[derive(Debug, Error, Clone, Copy, PartialEq, Eq)]
-pub enum EventSubscriptionError {
-    /// The subscription can no longer receive new events.
-    ///
-    /// Already queued events are delivered first. After the queue is drained,
-    /// `recv` and `try_recv` return this error when the hub disconnects the
-    /// subscriber, the hub is shut down, or the subscription is disconnected by
-    /// its overflow policy.
-    #[error("event subscription is disconnected")]
-    Disconnected,
 }

crates/irtt-client/src/event.rs

@@ -3,35 +3,36 @@ use std::{
     time::{Duration, Instant},
 };
 
-use crate::{session::NegotiatedParams, timing::ClientTimestamp};
+use crate::{session::NegotiationResult, timing::ClientTimestamp};
 
-/// Result of the IRTT open exchange.
+/// Successful negotiation with a live session ready for echo probes.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct SessionStarted {
+    /// Resolved remote socket address.
+    pub remote: SocketAddr,
+    /// Session token used on Echo and Close packets.
+    pub token: u64,
+    pub negotiation: NegotiationResult,
+    /// Client timestamp when the Open reply was accepted.
+    pub at: ClientTimestamp,
+}
+
+/// Successful negotiation-only exchange with no live probe session or token.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct NoTestCompleted {
+    pub remote: SocketAddr,
+    pub negotiation: NegotiationResult,
+    /// Client timestamp when the Open reply was accepted.
+    pub at: ClientTimestamp,
+}
+
+/// Result of the IRTT Open exchange, before any echo probes are driven.
 ///
-/// The lower-level [`Client`](crate::Client) API returns this before any echo
-/// probes are driven. Managed sessions publish the contained lifecycle event to
-/// subscribers immediately after a successful open.
+/// Managed sessions publish the same payload as a [`ClientEvent`] after Open.
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum OpenOutcome {
-    /// A normal probe session was opened.
-    Started {
-        /// Resolved remote socket address used by the UDP socket.
-        remote: SocketAddr,
-        /// Session token assigned by the server and used on echo/close packets.
-        token: u64,
-        /// Parameters returned by the server after negotiation.
-        negotiated: NegotiatedParams,
-        /// Lifecycle event corresponding to this outcome.
-        event: ClientEvent,
-    },
-    /// A no-test open exchange completed without starting a probe session.
-    NoTestCompleted {
-        /// Resolved remote socket address used by the UDP socket.
-        remote: SocketAddr,
-        /// Parameters returned by the server after negotiation.
-        negotiated: NegotiatedParams,
-        /// Lifecycle event corresponding to this outcome.
-        event: ClientEvent,
-    },
+    Started(SessionStarted),
+    NoTestCompleted(NoTestCompleted),
 }
 
 /// Event emitted by an IRTT client session.
@@ -44,31 +45,16 @@ pub enum OpenOutcome {
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum ClientEvent {
     /// A normal session has opened and is ready to send echo probes.
-    SessionStarted {
-        /// Resolved remote socket address.
-        remote: SocketAddr,
-        /// Session token assigned by the server.
-        token: u64,
-        /// Negotiated protocol parameters for this session.
-        negotiated: NegotiatedParams,
-        /// Client timestamp when the open reply was accepted.
-        at: ClientTimestamp,
-    },
-    /// A negotiation-only no-test exchange completed.
+    SessionStarted(SessionStarted),
+    /// A no-test exchange completed without creating a live session.
     ///
     /// No `EchoSent`, `EchoReply`, `EchoLoss`, or `SessionClosed` events are
-    /// expected for this open outcome.
-    NoTestCompleted {
-        /// Resolved remote socket address.
-        remote: SocketAddr,
-        /// Negotiated protocol parameters returned by the server.
-        negotiated: NegotiatedParams,
-        /// Client timestamp when the open reply was accepted.
-        at: ClientTimestamp,
-    },
-    /// The client sent a close request and considers the session closed.
+    /// expected for this outcome.
+    NoTestCompleted(NoTestCompleted),
+    /// The session closed locally or through an authenticated peer close.
     ///
-    /// This is a local lifecycle event, not an acknowledgement from the server.
+    /// For a peer close-flagged echo reply, the reply's measurement or
+    /// classification event is emitted immediately before this event.
     /// Managed sessions disconnect event subscribers after the worker exits,
     /// while leaving already queued events available to drain.
     SessionClosed {
@@ -91,17 +77,23 @@ 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,
-        /// Client wall/monotonic timestamp captured for the send.
+        /// 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
+        /// timeout deadline is computed from an earlier, private, pre-send
+        /// timestamp instead — see the client crate's `AGENTS.md`.
         sent_at: ClientTimestamp,
         /// Number of bytes passed to the UDP socket.
         bytes: usize,
-        /// Elapsed time spent in the socket send call.
+        /// Elapsed time spent in the socket send call, excluding protocol and
+        /// scheduler commit work.
         send_call: Duration,
-        /// Absolute difference between the scheduled send time and actual send
-        /// timestamp.
-        timer_error: Duration,
+        /// Absolute difference between the scheduled send time and the
+        /// post-send `sent_at` timestamp above; absent for low-level sends.
+        timer_error: Option<Duration>,
     },
 
     /// First in-window reply for a pending echo request.
@@ -114,7 +106,8 @@ pub enum ClientEvent {
         seq: u32,
         /// Resolved remote socket address.
         remote: SocketAddr,
-        /// Client timestamp recorded when the matching request was sent.
+        /// Client timestamp recorded immediately after the matching request
+        /// finished sending (see `ClientEvent::EchoSent::sent_at`).
         sent_at: ClientTimestamp,
         /// Client timestamp recorded when the reply was received.
         received_at: ClientTimestamp,
@@ -140,7 +133,10 @@ pub enum ClientEvent {
     EchoLoss {
         /// Wire sequence number that timed out.
         seq: u32,
-        /// Client timestamp recorded when the request was sent.
+        /// Client timestamp recorded immediately after the request finished
+        /// sending (see `ClientEvent::EchoSent::sent_at`). The timeout
+        /// deadline below is anchored to an earlier, private, pre-send
+        /// timestamp, not to this one.
         sent_at: ClientTimestamp,
         /// Monotonic deadline at which the probe was declared lost.
         timeout_at: std::time::Instant,
@@ -175,7 +171,8 @@ pub enum ClientEvent {
         highest_seen: u32,
         /// Resolved remote socket address.
         remote: SocketAddr,
-        /// Original client send timestamp, when still retained.
+        /// Original post-send client timestamp, when still retained (see
+        /// `ClientEvent::EchoSent::sent_at`).
         sent_at: Option<ClientTimestamp>,
         /// Client timestamp recorded when the late reply was received.
         received_at: ClientTimestamp,
@@ -249,6 +246,19 @@ 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,
@@ -340,12 +350,31 @@ pub struct OneWayDelaySample {
     /// Client-to-server delay.
     ///
     /// This is computed from the client send wall time and the server receive
-    /// wall time when both are available.
+    /// wall time when both are available. The client send endpoint is the
+    /// correlated Linux kernel TX timestamp for this send when one is
+    /// available and plausible for this send, and the userspace post-send wall
+    /// time otherwise. The server receive endpoint is whatever wall time the
+    /// peer reported; against this crate's own Tokio server runtime on Linux
+    /// (the `irtt-server` applet), that is its kernel receive timestamp when
+    /// one is available and plausible, and its userspace receive wall time
+    /// otherwise. Against another IRTT-compatible peer, or an application
+    /// driving `irtt_server::ServerCore::handle_datagram` directly, the
+    /// client has no way to know which clock source produced it — the public
+    /// `ServerCore` API never supplies a kernel timestamp of its own accord.
+    /// `RttSample::raw` is unaffected and remains a userspace
+    /// monotonic measurement, but `adjusted` and `effective` can still shift:
+    /// when the session negotiated wall-clock timing rather than monotonic,
+    /// server processing time is derived from this same server receive
+    /// endpoint.
     pub client_to_server: Option<SignedDuration>,
     /// Server-to-client delay.
     ///
     /// This is computed from the server send wall time and the client receive
-    /// wall time when both are available.
+    /// wall time when both are available. The client receive endpoint is the
+    /// kernel receive timestamp reported with the datagram when one is
+    /// available and plausible for this receive, and the userspace receive wall
+    /// time otherwise. RTT is unaffected and remains a userspace monotonic
+    /// measurement.
     pub server_to_client: Option<SignedDuration>,
 }
 
@@ -358,7 +387,10 @@ pub struct OneWayDelaySample {
 pub struct ReceivedStatsSample {
     /// Server-reported count of received packets, when available.
     pub count: Option<u32>,
-    /// Server-reported receive window value, when available.
+    /// Raw server-reported receive window bitmap, when available.
+    ///
+    /// The bitmap is preserved exactly as it appeared on the wire; the client
+    /// does not interpret its bits.
     pub window: Option<u64>,
 }
 
@@ -371,5 +403,11 @@ pub struct PacketMeta {
     pub traffic_class: Option<u8>,
     pub dscp: Option<u8>,
     pub ecn: Option<u8>,
+    /// Kernel software receive timestamp reported with the datagram, where the
+    /// platform provides one.
+    ///
+    /// This is the raw observed value, reported whether or not it was accepted
+    /// as the downstream one-way delay endpoint. It is a kernel software
+    /// timestamp, not a NIC hardware ingress time.
     pub kernel_rx_timestamp: Option<std::time::SystemTime>,
 }

crates/irtt-client/src/lib.rs

@@ -3,6 +3,8 @@
 //! `irtt-client` opens IRTT-compatible sessions, sends echo probes, receives
 //! replies, classifies loss/late/duplicate packets, and emits [`ClientEvent`]
 //! values for callers to consume directly or aggregate with `irtt-stats`.
+//! With the `tokio` feature enabled, `AsyncClient` provides the same low-level
+//! lifecycle for callers that own a Tokio runtime and drive readiness directly.
 //!
 //! Timing values intentionally preserve signed measurement semantics. When
 //! server timing is available, [`RttSample::effective`] is adjusted for server
@@ -11,76 +13,71 @@
 //! also signed when the required wall-clock timestamps are available; negative
 //! values usually indicate client/server clock skew.
 //!
-//! A managed session can drive the socket loop on a worker thread and publish
-//! events through a subscription:
+//! [`Client`] is the runtime-free low-level blocking adapter and requires no
+//! Tokio dependency at all; it is what a caller without a runtime, or that
+//! 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. Both adapters send one probe whenever called; callers own cadence
+//! and run duration, using `negotiation()` after Open. Sends return a
+//! [`SendReceipt`] after socket acceptance and session commitment;
+//! [`SendProbeError`] distinguishes uncommitted failures from post-commit
+//! failures carrying that receipt. Convert a receipt to [`ClientEvent`] for
+//! presentation or statistics. [`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
+//! current-thread runtime for callers that want managed multi-target
+//! behavior without touching Tokio themselves.
 //!
-//! ```no_run
-//! use std::time::Duration;
+//! A successful [`OpenOutcome`] carries either [`SessionStarted`] (with a live
+//! token) or [`NoTestCompleted`] (terminal, with no probe session). Lifecycle
+//! events use these same payload types. Their [`NegotiationResult`] separates
+//! typed [`AcceptedSessionParameters`] from the exact decoded peer `Params` and
+//! accepted [`NegotiationChange`] records. Use `accepted.interval` and
+//! `accepted.duration` for cadence and lifetime, `accepted.dscp` for the public
+//! DSCP codepoint, and `peer_params` for wire diagnostics. Strict/Loose policy
+//! compares the actual request and reply wire values before deriving accepted
+//! semantics. Both adapters' `negotiation()` accessors return only a live
+//! session's result; no-test completion leaves no current session.
 //!
-//! use irtt_client::{ClientConfig, ClientEvent, ManagedClient, SubscriberConfig};
+//! See `examples/` in the repository for a runnable example of each tier.
 //!
-//! # fn main() -> Result<(), Box<dyn std::error::Error>> {
-//! let config = ClientConfig {
-//!     server_addr: "127.0.0.1:2112".to_owned(),
-//!     duration: Some(Duration::from_secs(10)),
-//!     interval: Duration::from_secs(1),
-//!     ..ClientConfig::default()
-//! };
-//!
-//! let (session, events) =
-//!     ManagedClient::start_with_subscription(config, SubscriberConfig::default())?;
-//!
-//! while let Ok(event) = events.recv() {
-//!     match event {
-//!         ClientEvent::EchoReply { seq, rtt, .. } => {
-//!             println!("seq={seq} effective_rtt_us={}", rtt.effective.as_micros());
-//!         }
-//!         ClientEvent::SessionClosed { .. } => break,
-//!         _ => {}
-//!     }
-//! }
-//!
-//! let _outcome = session.join()?;
-//! # Ok(())
-//! # }
-//! ```
-//!
-#![cfg_attr(
-    not(all(target_os = "linux", feature = "ancillary")),
-    forbid(unsafe_code)
-)]
-#![cfg_attr(all(target_os = "linux", feature = "ancillary"), deny(unsafe_code))]
+#![forbid(unsafe_code)]
 
+#[cfg(feature = "tokio")]
+mod async_client;
+mod auth;
 mod client;
 mod config;
 mod error;
 mod event;
-mod managed;
+pub mod managed;
 mod metadata;
 mod probe;
 mod receive;
-mod runtime;
+mod send;
 mod session;
 mod socket;
 mod socket_options;
 mod timing;
 
+#[cfg(feature = "tokio")]
+pub use async_client::AsyncClient;
+pub use auth::{Authentication, HmacKey};
 pub use client::Client;
 pub use config::{
-    ClientAuthConfig, ClientConfig, NegotiationPolicy, RecvBudget, RunMode, SocketConfig,
-    MAX_DSCP_CODEPOINT, MAX_SERVER_FILL_BYTES, MAX_TTL, MAX_UDP_PAYLOAD_LENGTH,
+    AddressFamily, ClientConfig, NegotiationPolicy, OpenPolicy, RecvBudget, RunMode,
+    SessionRequest, SocketConfig, MAX_DSCP_CODEPOINT, MAX_SERVER_FILL_BYTES, MAX_TTL,
+    MAX_UDP_PAYLOAD_LENGTH,
 };
-pub use error::{ClientError, EventSubscriptionError};
+pub use error::ClientError;
 pub use event::{
-    ClientEvent, OneWayDelaySample, OpenOutcome, PacketMeta, ReceivedStatsSample, RttSample,
-    ServerTiming, SignedDuration, WarningKind,
+    ClientEvent, NoTestCompleted, OneWayDelaySample, OpenOutcome, PacketMeta, ReceivedStatsSample,
+    RttSample, ServerTiming, SessionStarted, SignedDuration, WarningKind,
 };
-pub use managed::{
-    CancellationToken, EventHub, EventSubscription, ManagedClient, ManagedClientGroup,
-    ManagedClientGroupConfig, ManagedClientGroupSession, ManagedClientSession,
-    ManagedGroupEndReason, ManagedGroupOutcome, ManagedGroupPacing, ManagedTargetConfig,
-    ManagedTargetEndReason, ManagedTargetOutcome, SessionEndReason, SessionOutcome,
-    SubscriberConfig, SubscriberOverflow, TargetEvent, TargetEventSubscription, TargetId,
-};
-pub use session::{NegotiatedParams, NegotiationRestriction};
+pub use send::{SendProbeError, SendReceipt};
+pub use session::{AcceptedSessionParameters, NegotiationChange, NegotiationResult};
 pub use timing::ClientTimestamp;

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

@@ -0,0 +1,175 @@
+use std::{
+    thread::{self, JoinHandle},
+    time::Duration,
+};
+
+use thiserror::Error;
+use tokio::runtime::{Builder, Runtime};
+
+use super::{
+    ManagedClient, ManagedClientConfig, ManagedClientHandle, ManagedClientTask, ManagedConfigError,
+    ManagedEventSubscription, ManagedOutcome, ManagedSubscribeError, ManagedTargetConfig,
+};
+
+const BLOCKING_RUNTIME_SHUTDOWN_TIMEOUT: Duration = Duration::from_millis(100);
+
+/// Owns the runtime used exclusively by the blocking managed worker.
+pub(super) struct WorkerRuntime {
+    runtime: Option<Runtime>,
+}
+
+impl WorkerRuntime {
+    pub(super) fn new(runtime: Runtime) -> Self {
+        Self {
+            runtime: Some(runtime),
+        }
+    }
+
+    fn block_on<F: std::future::Future>(&self, task: F) -> F::Output {
+        self.runtime
+            .as_ref()
+            .expect("worker runtime is available until shutdown")
+            .block_on(task)
+    }
+
+    /// Shut down residual runtime work without delaying managed completion indefinitely.
+    pub(super) fn shutdown(mut self) {
+        self.runtime
+            .take()
+            .expect("worker runtime is available until shutdown")
+            .shutdown_timeout(BLOCKING_RUNTIME_SHUTDOWN_TIMEOUT);
+    }
+}
+
+impl Drop for WorkerRuntime {
+    fn drop(&mut self) {
+        if let Some(runtime) = self.runtime.take() {
+            runtime.shutdown_background();
+        }
+    }
+}
+
+/// Failure to start a blocking managed client owner.
+#[derive(Debug, Error)]
+pub enum BlockingManagedStartError {
+    /// The managed task configuration was invalid.
+    #[error(transparent)]
+    Config(#[from] ManagedConfigError),
+
+    /// The managed event subscription could not be created before startup.
+    #[error(transparent)]
+    Subscribe(#[from] ManagedSubscribeError),
+
+    /// The dedicated Tokio runtime could not be created.
+    #[error("failed to create blocking managed Tokio runtime: {source}")]
+    Runtime {
+        #[source]
+        source: std::io::Error,
+    },
+
+    /// The dedicated worker thread could not be spawned.
+    #[error("failed to spawn blocking managed worker thread: {source}")]
+    ThreadSpawn {
+        #[source]
+        source: std::io::Error,
+    },
+}
+
+/// Failure to obtain completion from a blocking managed client owner.
+#[derive(Debug, Error, Eq, PartialEq)]
+pub enum BlockingManagedJoinError {
+    /// The dedicated managed worker thread panicked.
+    #[error("blocking managed worker thread panicked")]
+    WorkerPanicked,
+}
+
+/// Blocking completion owner for one unified managed Tokio task.
+///
+/// This owner runs exactly one [`ManagedClient`] task on one dedicated OS thread
+/// with its own current-thread Tokio runtime. Dropping a live owner requests a
+/// graceful stop and synchronously joins that worker, so drop may block while
+/// bounded managed cleanup completes.
+#[must_use = "dropping the blocking managed owner requests stop and joins its worker"]
+pub struct BlockingManagedClient {
+    handle: ManagedClientHandle,
+    worker: Option<JoinHandle<ManagedOutcome>>,
+}
+
+impl BlockingManagedClient {
+    /// Validate configuration, create a dedicated runtime, and start its worker.
+    pub fn start(
+        config: ManagedClientConfig,
+        targets: Vec<ManagedTargetConfig>,
+    ) -> Result<Self, BlockingManagedStartError> {
+        let (task, handle) = ManagedClient::task(config, targets)?;
+        Self::start_task(task, handle)
+    }
+
+    /// Validate configuration, subscribe to presentation events, and start a
+    /// dedicated managed worker.
+    ///
+    /// The returned subscription exists before the managed task receives its
+    /// first poll, so it cannot miss startup events because of subscription
+    /// ordering.
+    pub fn start_with_subscription(
+        config: ManagedClientConfig,
+        targets: Vec<ManagedTargetConfig>,
+    ) -> Result<(Self, ManagedEventSubscription), BlockingManagedStartError> {
+        let (task, handle) = ManagedClient::task(config, targets)?;
+        let subscription = handle.subscribe()?;
+        let owner = Self::start_task(task, handle)?;
+        Ok((owner, subscription))
+    }
+
+    fn start_task(
+        task: ManagedClientTask,
+        handle: ManagedClientHandle,
+    ) -> Result<Self, BlockingManagedStartError> {
+        let runtime = Builder::new_current_thread()
+            .enable_io()
+            .enable_time()
+            .build()
+            .map_err(|source| BlockingManagedStartError::Runtime { source })?;
+        let runtime = WorkerRuntime::new(runtime);
+        let worker = thread::Builder::new()
+            .name("irtt-managed".to_owned())
+            .spawn(move || {
+                let outcome = runtime.block_on(task);
+                runtime.shutdown();
+                outcome
+            })
+            .map_err(|source| BlockingManagedStartError::ThreadSpawn { source })?;
+
+        Ok(Self {
+            handle,
+            worker: Some(worker),
+        })
+    }
+
+    /// Return a cloned managed control and observation capability.
+    pub fn handle(&self) -> ManagedClientHandle {
+        self.handle.clone()
+    }
+
+    /// Wait synchronously for the managed task's authoritative outcome.
+    pub fn join(mut self) -> Result<ManagedOutcome, BlockingManagedJoinError> {
+        self.join_worker()
+    }
+
+    fn join_worker(&mut self) -> Result<ManagedOutcome, BlockingManagedJoinError> {
+        self.worker
+            .take()
+            .expect("blocking managed worker is joined at most once")
+            .join()
+            .map_err(|_| BlockingManagedJoinError::WorkerPanicked)
+    }
+}
+
+impl Drop for BlockingManagedClient {
+    fn drop(&mut self) {
+        if self.worker.is_some() {
+            let _receipt = self.handle.stop();
+            let _ = self.join_worker();
+        }
+    }
+}

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

@@ -1,52 +0,0 @@
-use std::sync::{
-    atomic::{AtomicBool, Ordering},
-    Arc,
-};
-
-/// Cloneable cooperative cancellation flag.
-///
-/// Managed sessions use this internally to ask their worker loop to stop. It is
-/// exported for callers that want the same simple cancellation primitive in
-/// code built around `irtt-client`.
-#[derive(Debug, Clone, Default)]
-pub struct CancellationToken {
-    cancelled: Arc<AtomicBool>,
-}
-
-impl CancellationToken {
-    /// Create a token in the non-cancelled state.
-    pub fn new() -> Self {
-        Self::default()
-    }
-
-    /// Mark the token as cancelled.
-    ///
-    /// Cancellation is idempotent and is visible through all clones of the
-    /// token.
-    pub fn cancel(&self) {
-        self.cancelled.store(true, Ordering::SeqCst);
-    }
-
-    /// Return whether cancellation has been requested.
-    #[must_use]
-    pub fn is_cancelled(&self) -> bool {
-        self.cancelled.load(Ordering::SeqCst)
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn cancel_is_idempotent_and_visible_through_clones() {
-        let token = CancellationToken::new();
-        let clone = token.clone();
-
-        token.cancel();
-        token.cancel();
-
-        assert!(token.is_cancelled());
-        assert!(clone.is_cancelled());
-    }
-}

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

@@ -1,460 +0,0 @@
-use std::{
-    collections::{HashMap, VecDeque},
-    sync::{
-        atomic::{AtomicU64, Ordering},
-        Arc, Condvar, Mutex, Weak,
-    },
-};
-
-use crate::{error::EventSubscriptionError, event::ClientEvent};
-
-/// Configuration for one managed event subscriber.
-///
-/// Each subscriber has an independent bounded queue. The queue bounds memory
-/// growth when event production is faster than that subscriber's consumer.
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub struct SubscriberConfig {
-    /// Maximum number of events buffered for this subscriber.
-    ///
-    /// Must be greater than zero.
-    pub capacity: usize,
-    /// Policy applied when publishing to a full subscriber queue.
-    pub overflow: SubscriberOverflow,
-}
-
-impl Default for SubscriberConfig {
-    fn default() -> Self {
-        Self {
-            capacity: 1024,
-            overflow: SubscriberOverflow::DropNewest,
-        }
-    }
-}
-
-/// Overflow behavior for a bounded event subscription queue.
-///
-/// These policies are applied independently per subscriber when that
-/// subscriber's queue is full.
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub enum SubscriberOverflow {
-    /// Leave the existing queue unchanged and discard the newly published event.
-    DropNewest,
-    /// Remove the oldest queued event and enqueue the newly published event.
-    DropOldest,
-    /// Disconnect the subscriber and clear its queue.
-    Disconnect,
-}
-
-/// Publish/subscribe fan-out for managed event values.
-///
-/// `EventHub` is used by managed sessions internally and is also exported for
-/// callers that want the same bounded subscription behavior around their own
-/// event producer. Publishing clones each event once per subscriber.
-#[derive(Debug)]
-pub struct EventHub<T = ClientEvent> {
-    inner: Arc<HubInner<T>>,
-}
-
-#[derive(Debug)]
-struct HubInner<T> {
-    next_id: AtomicU64,
-    subscribers: Mutex<HashMap<u64, Arc<SubscriberInner<T>>>>,
-}
-
-/// Handle for receiving managed client events.
-///
-/// Each subscription has its own bounded queue configured by
-/// [`SubscriberConfig`]. The configured [`SubscriberOverflow`] policy applies
-/// when that queue is full. Dropping the handle unregisters the subscriber.
-#[must_use = "dropping the subscription unregisters it"]
-#[derive(Debug)]
-pub struct EventSubscription<T = ClientEvent> {
-    id: u64,
-    hub: Weak<HubInner<T>>,
-    inner: Arc<SubscriberInner<T>>,
-}
-
-#[derive(Debug)]
-struct SubscriberInner<T> {
-    state: Mutex<SubscriberState<T>>,
-    available: Condvar,
-    config: SubscriberConfig,
-}
-
-#[derive(Debug)]
-struct SubscriberState<T> {
-    queue: VecDeque<T>,
-    connected: bool,
-}
-
-impl<T> Clone for EventHub<T> {
-    fn clone(&self) -> Self {
-        Self {
-            inner: self.inner.clone(),
-        }
-    }
-}
-
-impl<T> EventHub<T> {
-    /// Create an empty event hub with no subscribers.
-    pub fn new() -> Self {
-        Self {
-            inner: Arc::new(HubInner {
-                next_id: AtomicU64::new(1),
-                subscribers: Mutex::new(HashMap::new()),
-            }),
-        }
-    }
-
-    /// Register a new subscriber with its own bounded queue.
-    ///
-    /// Returns an error when `config.capacity` is zero.
-    pub fn subscribe(
-        &self,
-        config: SubscriberConfig,
-    ) -> Result<EventSubscription<T>, crate::ClientError> {
-        if config.capacity == 0 {
-            return Err(crate::ClientError::InvalidConfig {
-                reason: "subscriber capacity must be greater than zero".to_owned(),
-            });
-        }
-
-        let id = self.inner.next_id.fetch_add(1, Ordering::Relaxed);
-        let inner = Arc::new(SubscriberInner {
-            state: Mutex::new(SubscriberState {
-                queue: VecDeque::with_capacity(config.capacity),
-                connected: true,
-            }),
-            available: Condvar::new(),
-            config,
-        });
-        self.inner
-            .subscribers
-            .lock()
-            .expect("event hub mutex poisoned")
-            .insert(id, inner.clone());
-
-        Ok(EventSubscription {
-            id,
-            hub: Arc::downgrade(&self.inner),
-            inner,
-        })
-    }
-
-    /// Disconnect all subscribers after leaving their already queued events
-    /// available to drain.
-    pub fn disconnect_all(&self) {
-        let subscribers: Vec<Arc<SubscriberInner<T>>> = self
-            .inner
-            .subscribers
-            .lock()
-            .expect("event hub mutex poisoned")
-            .drain()
-            .map(|(_, subscriber)| subscriber)
-            .collect();
-
-        for subscriber in subscribers {
-            subscriber.disconnect();
-        }
-    }
-
-    #[cfg(test)]
-    fn subscriber_count(&self) -> usize {
-        self.inner
-            .subscribers
-            .lock()
-            .expect("event hub mutex poisoned")
-            .len()
-    }
-}
-
-impl<T: Clone> EventHub<T> {
-    /// Publish an event to all currently connected subscribers.
-    ///
-    /// Slow subscribers are handled according to their
-    /// [`SubscriberOverflow`] policy. Publishing does not block waiting for a
-    /// subscriber to consume queued events.
-    pub fn publish(&self, event: T) {
-        let subscribers: Vec<(u64, Arc<SubscriberInner<T>>)> = self
-            .inner
-            .subscribers
-            .lock()
-            .expect("event hub mutex poisoned")
-            .iter()
-            .map(|(id, subscriber)| (*id, subscriber.clone()))
-            .collect();
-
-        let mut disconnected = Vec::new();
-        for (id, subscriber) in subscribers {
-            // Events are cloned per subscriber; bounded queues keep slow
-            // consumers from causing unbounded memory growth.
-            if !subscriber.publish(event.clone()) {
-                disconnected.push(id);
-            }
-        }
-
-        if disconnected.is_empty() {
-            return;
-        }
-
-        let mut subscribers = self
-            .inner
-            .subscribers
-            .lock()
-            .expect("event hub mutex poisoned");
-        for id in disconnected {
-            subscribers.remove(&id);
-        }
-    }
-}
-
-impl<T> Default for EventHub<T> {
-    fn default() -> Self {
-        Self::new()
-    }
-}
-
-impl<T> EventSubscription<T> {
-    /// Block until the next queued event is available.
-    ///
-    /// If the subscription is disconnected, this returns
-    /// [`EventSubscriptionError::Disconnected`] after any already queued events
-    /// have been drained.
-    pub fn recv(&self) -> Result<T, EventSubscriptionError> {
-        let mut state = self.inner.state.lock().expect("subscriber mutex poisoned");
-        loop {
-            if let Some(event) = state.queue.pop_front() {
-                return Ok(event);
-            }
-            if !state.connected {
-                return Err(EventSubscriptionError::Disconnected);
-            }
-            state = self
-                .inner
-                .available
-                .wait(state)
-                .expect("subscriber mutex poisoned");
-        }
-    }
-
-    /// Try to receive one queued event without blocking.
-    ///
-    /// Returns `Ok(None)` when the subscription is still connected but no event
-    /// is queued. If the subscription is disconnected, this returns
-    /// [`EventSubscriptionError::Disconnected`] after any already queued events
-    /// have been drained.
-    pub fn try_recv(&self) -> Result<Option<T>, EventSubscriptionError> {
-        let mut state = self.inner.state.lock().expect("subscriber mutex poisoned");
-        if let Some(event) = state.queue.pop_front() {
-            return Ok(Some(event));
-        }
-        if !state.connected {
-            return Err(EventSubscriptionError::Disconnected);
-        }
-        Ok(None)
-    }
-}
-
-impl<T> Drop for EventSubscription<T> {
-    fn drop(&mut self) {
-        self.inner.disconnect();
-        if let Some(hub) = self.hub.upgrade() {
-            hub.subscribers
-                .lock()
-                .expect("event hub mutex poisoned")
-                .remove(&self.id);
-        }
-    }
-}
-
-impl<T> SubscriberInner<T> {
-    fn publish(&self, event: T) -> bool {
-        let mut state = self.state.lock().expect("subscriber mutex poisoned");
-        if !state.connected {
-            return false;
-        }
-
-        if state.queue.len() < self.config.capacity {
-            state.queue.push_back(event);
-            self.available.notify_one();
-            return true;
-        }
-
-        match self.config.overflow {
-            SubscriberOverflow::DropNewest => true,
-            SubscriberOverflow::DropOldest => {
-                state.queue.pop_front();
-                state.queue.push_back(event);
-                self.available.notify_one();
-                true
-            }
-            SubscriberOverflow::Disconnect => {
-                state.queue.clear();
-                state.connected = false;
-                self.available.notify_all();
-                false
-            }
-        }
-    }
-
-    fn disconnect(&self) {
-        let mut state = self.state.lock().expect("subscriber mutex poisoned");
-        state.connected = false;
-        self.available.notify_all();
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::{ClientTimestamp, WarningKind};
-
-    fn event(n: usize) -> ClientEvent {
-        ClientEvent::Warning {
-            kind: WarningKind::UntrackedReply,
-            message: format!("event-{n}"),
-            at: ClientTimestamp::now(),
-        }
-    }
-
-    fn event_message(event: ClientEvent) -> String {
-        match event {
-            ClientEvent::Warning { message, .. } => message,
-            other => panic!("unexpected event: {other:?}"),
-        }
-    }
-
-    fn assert_next(
-        sub: &EventSubscription,
-        expected: Result<Option<&str>, EventSubscriptionError>,
-    ) {
-        match (sub.try_recv(), expected) {
-            (Ok(Some(event)), Ok(Some(message))) => assert_eq!(event_message(event), message),
-            (Ok(None), Ok(None)) => {}
-            (Err(actual), Err(expected)) => assert_eq!(actual, expected),
-            (actual, expected) => panic!("expected {expected:?}, got {actual:?}"),
-        }
-    }
-
-    #[test]
-    fn publishes_to_multiple_subscribers() {
-        let hub = EventHub::new();
-        let a = hub.subscribe(SubscriberConfig::default()).unwrap();
-        let b = hub.subscribe(SubscriberConfig::default()).unwrap();
-
-        hub.publish(event(1));
-
-        assert_eq!(event_message(a.try_recv().unwrap().unwrap()), "event-1");
-        assert_eq!(event_message(b.try_recv().unwrap().unwrap()), "event-1");
-    }
-
-    #[test]
-    fn full_subscriber_overflow_policy_is_applied() {
-        let cases = [
-            (
-                SubscriberOverflow::DropNewest,
-                Ok(Some("event-1")),
-                Ok(None),
-            ),
-            (
-                SubscriberOverflow::DropOldest,
-                Ok(Some("event-2")),
-                Ok(None),
-            ),
-            (
-                SubscriberOverflow::Disconnect,
-                Err(EventSubscriptionError::Disconnected),
-                Err(EventSubscriptionError::Disconnected),
-            ),
-        ];
-
-        for (overflow, first_expected, second_expected) in cases {
-            let hub = EventHub::new();
-            let sub = hub
-                .subscribe(SubscriberConfig {
-                    capacity: 1,
-                    overflow,
-                })
-                .unwrap();
-
-            hub.publish(event(1));
-            hub.publish(event(2));
-
-            assert_next(&sub, first_expected);
-            assert_next(&sub, second_expected);
-        }
-    }
-
-    #[test]
-    fn full_subscriber_does_not_prevent_other_delivery() {
-        let hub = EventHub::new();
-        let slow = hub
-            .subscribe(SubscriberConfig {
-                capacity: 1,
-                overflow: SubscriberOverflow::DropNewest,
-            })
-            .unwrap();
-        let fast = hub
-            .subscribe(SubscriberConfig {
-                capacity: 4,
-                overflow: SubscriberOverflow::DropNewest,
-            })
-            .unwrap();
-
-        hub.publish(event(1));
-        hub.publish(event(2));
-
-        assert_eq!(event_message(slow.try_recv().unwrap().unwrap()), "event-1");
-        assert_eq!(event_message(fast.try_recv().unwrap().unwrap()), "event-1");
-        assert_eq!(event_message(fast.try_recv().unwrap().unwrap()), "event-2");
-    }
-
-    #[test]
-    fn subscribing_after_events_does_not_replay() {
-        let hub = EventHub::new();
-        hub.publish(event(1));
-
-        let sub = hub.subscribe(SubscriberConfig::default()).unwrap();
-
-        assert!(sub.try_recv().unwrap().is_none());
-    }
-
-    #[test]
-    fn dropping_subscription_unregisters_from_hub() {
-        let hub: EventHub = EventHub::new();
-        let sub = hub.subscribe(SubscriberConfig::default()).unwrap();
-        assert_eq!(hub.subscriber_count(), 1);
-
-        drop(sub);
-
-        assert_eq!(hub.subscriber_count(), 0);
-    }
-
-    #[test]
-    fn disconnect_all_wakes_blocking_receivers() {
-        let hub: EventHub = EventHub::new();
-        let sub = hub.subscribe(SubscriberConfig::default()).unwrap();
-        hub.disconnect_all();
-
-        assert_eq!(
-            sub.recv().unwrap_err(),
-            EventSubscriptionError::Disconnected
-        );
-    }
-
-    #[test]
-    fn session_closed_event_can_be_queued() {
-        let hub = EventHub::new();
-        let sub = hub.subscribe(SubscriberConfig::default()).unwrap();
-        hub.publish(ClientEvent::SessionClosed {
-            remote: "127.0.0.1:1".parse().unwrap(),
-            token: 1,
-            at: ClientTimestamp::now(),
-        });
-
-        assert!(matches!(
-            sub.recv().unwrap(),
-            ClientEvent::SessionClosed { token: 1, .. }
-        ));
-    }
-}

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

@@ -1,13 +1,20 @@
-mod cancellation;
-mod group;
-mod hub;
-mod runner;
+mod target_id;
 
-pub use cancellation::CancellationToken;
-pub use group::{
-    ManagedClientGroup, ManagedClientGroupConfig, ManagedClientGroupSession, ManagedGroupEndReason,
-    ManagedGroupOutcome, ManagedGroupPacing, ManagedTargetConfig, ManagedTargetEndReason,
-    ManagedTargetOutcome, TargetEvent, TargetEventSubscription, TargetId,
-};
-pub use hub::{EventHub, EventSubscription, SubscriberConfig, SubscriberOverflow};
-pub use runner::{ManagedClient, ManagedClientSession, SessionEndReason, SessionOutcome};
+pub use target_id::TargetId;
+
+#[cfg(feature = "tokio")]
+mod blocking;
+#[cfg(feature = "tokio")]
+mod model;
+#[cfg(feature = "tokio")]
+mod task;
+
+#[cfg(feature = "tokio")]
+pub use blocking::*;
+#[cfg(feature = "tokio")]
+pub use model::*;
+#[cfg(feature = "tokio")]
+pub use task::*;
+
+#[cfg(feature = "tokio")]
+mod schedule;