chore(deps): update github actions

irtt-client exposes a synchronous wait for managed target-set updates and keeps its packaged test dependency resolvable from crates.io. irtt-rs adds stdin-managed desired target sets and per-target HMAC configuration.

.gitea/workflows/ci.yml

@@ -7,7 +7,6 @@ on:
   pull_request:
     branches:
       - main
-  merge_group:
   workflow_dispatch:
 
 permissions:
@@ -32,7 +31,7 @@ jobs:
         uses: actions-rust-lang/setup-rust-toolchain@166cdcfd11aee3cb47222f9ddb555ce30ddb9659 # v1
         with:
           components: rustfmt
-          cache-key: fmt
+          cache: false
 
       - name: Check formatting
         uses: actions-rust-lang/rustfmt@4066006ec54a31931b9b1fddfd38f2fdf2d27143 # v1
@@ -52,7 +51,7 @@ jobs:
         uses: actions-rust-lang/setup-rust-toolchain@166cdcfd11aee3cb47222f9ddb555ce30ddb9659 # v1
         with:
           components: clippy
-          cache-key: clippy
+          cache: false
 
       - name: Run clippy
         run: |
@@ -79,46 +78,22 @@ jobs:
       matrix:
         include:
           - task: check
-            runner: ubuntu-24.04
             target: x86_64-unknown-linux-gnu
             musl: false
 
           - task: test
-            runner: ubuntu-24.04
             target: x86_64-unknown-linux-gnu
             musl: false
 
           - task: check
-            runner: ubuntu-24.04
             target: x86_64-unknown-linux-musl
             musl: true
 
           - task: test
-            runner: ubuntu-24.04
             target: x86_64-unknown-linux-musl
             musl: true
 
-          - task: check
+    runs-on: ubuntu-latest
-            runner: ubuntu-24.04-arm
-            target: aarch64-unknown-linux-gnu
-            musl: false
-
-          - task: test
-            runner: ubuntu-24.04-arm
-            target: aarch64-unknown-linux-gnu
-            musl: false
-
-          - task: check
-            runner: ubuntu-24.04-arm
-            target: aarch64-unknown-linux-musl
-            musl: true
-
-          - task: test
-            runner: ubuntu-24.04-arm
-            target: aarch64-unknown-linux-musl
-            musl: true
-
-    runs-on: ${{ matrix.runner }}
     timeout-minutes: 25
 
     steps:
@@ -137,7 +112,7 @@ jobs:
         uses: actions-rust-lang/setup-rust-toolchain@166cdcfd11aee3cb47222f9ddb555ce30ddb9659 # v1
         with:
           target: ${{ matrix.target }}
-          cache-key: ${{ matrix.task }}-${{ matrix.target }}
+          cache: false
 
       - name: Run ${{ matrix.task }} with all features
         run: |
@@ -174,7 +149,7 @@ jobs:
       - name: Install Rust toolchain
         uses: actions-rust-lang/setup-rust-toolchain@166cdcfd11aee3cb47222f9ddb555ce30ddb9659 # v1
         with:
-          cache-key: docs
+          cache: false
 
       - name: Check docs
         run: |
@@ -183,3 +158,6 @@ jobs:
             --all-features \
             --no-deps \
             --locked
+
+      - name: Run doctests
+        run: cargo test --workspace --doc --all-features --locked

.gitea/workflows/docker-publish.yml

@@ -21,7 +21,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
 
       - name: Determine image tags
         id: meta
@@ -42,10 +42,10 @@ jobs:
       # (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@v3
+        uses: docker/setup-buildx-action@f87e5991a6d7451dcb8d9637bfbc97413f497069 # v4
 
       - name: Log in to Gitea Container Registry
-        uses: docker/login-action@v3
+        uses: docker/login-action@dbcb813823bdd20940b903addbd779551569679f # v4
         with:
           registry: ${{ env.GITEA_REGISTRY }}
           # The automatic per-job token comes back unauthorized for package
@@ -55,7 +55,7 @@ jobs:
           password: ${{ secrets.REGISTRY_TOKEN }}
 
       - name: Log in to GHCR
-        uses: docker/login-action@v3
+        uses: docker/login-action@dbcb813823bdd20940b903addbd779551569679f # v4
         with:
           registry: ${{ env.GHCR_REGISTRY }}
           username: ${{ secrets.GHCR_USERNAME }}
@@ -76,7 +76,7 @@ jobs:
       # below), never a separate build, so the hash matches everywhere.
       - name: Build and push to Gitea
         id: build
-        uses: docker/build-push-action@v6
+        uses: docker/build-push-action@c3c9e263c25d99ce0380d002d59b67737d91b0dc # v7
         with:
           context: .
           platforms: linux/amd64,linux/arm64

.gitea/workflows/fuzz.yml

@@ -1,4 +1,4 @@
-name: Proto Fuzz Smoke
+name: Fuzz Smoke
 
 on:
   push:
@@ -16,6 +16,9 @@ env:
   CARGO_TERM_COLOR: always
   # Pinned for reproducibility; bump deliberately alongside `fuzz/Cargo.lock`.
   CARGO_FUZZ_VERSION: 0.13.1
+  CARGO_FUZZ_SHA256: 86edc9b8f20c29ff07c3e5fcd67bc3f0784b3b960a5428635060f20d50555461
+  FUZZ_TOOLCHAIN: nightly-x86_64-unknown-linux-gnu
+  FUZZ_TARGET: x86_64-unknown-linux-gnu
 
 jobs:
   fuzz-smoke:
@@ -32,22 +35,33 @@ jobs:
       - name: Install stable Rust toolchain
         uses: actions-rust-lang/setup-rust-toolchain@166cdcfd11aee3cb47222f9ddb555ce30ddb9659 # v1
         with:
-          cache-key: fuzz
+          cache: false
 
       - name: Install nightly Rust toolchain
         # Installed alongside, but deliberately not made the directory
         # default: cargo-fuzz itself is built with the default stable
         # toolchain below, and only `fuzz build`/`fuzz run` are run with
-        # `+nightly`. Building cargo-fuzz's own dependency tree under a
+        # the GNU-host nightly below. Building cargo-fuzz's own dependency
-        # nightly override can trip build scripts (e.g. rustix) that gate
+        # tree under a nightly override can trip build scripts (e.g. rustix) that gate
         # unstable internal attributes on detecting a nightly compiler.
-        run: rustup toolchain install nightly --profile minimal --no-self-update
+        run: rustup toolchain install "${FUZZ_TOOLCHAIN}" --profile minimal --no-self-update
 
       - name: Install cargo-fuzz
-        run: cargo install cargo-fuzz --locked --version "${CARGO_FUZZ_VERSION}"
+        run: |
+          set -euo pipefail
+          archive="cargo-fuzz-${CARGO_FUZZ_VERSION}-x86_64-unknown-linux-musl.tar.gz"
+          curl --fail --show-error --location --retry 3 \
+            "https://github.com/rust-fuzz/cargo-fuzz/releases/download/${CARGO_FUZZ_VERSION}/${archive}" \
+            --output "$archive"
+          echo "${CARGO_FUZZ_SHA256}  ${archive}" | sha256sum --check --status -
+          tar -xzf "$archive" cargo-fuzz
+          install -Dm755 cargo-fuzz "${RUNNER_TEMP}/bin/cargo-fuzz"
+          echo "${RUNNER_TEMP}/bin" >> "$GITHUB_PATH"
 
       - name: Build all fuzz targets
-        run: cargo +nightly fuzz build
+        # libFuzzer sanitizers require dynamically linked GNU binaries; the
+        # runner's default Rust host can be static musl.
+        run: RUSTUP_TOOLCHAIN="${FUZZ_TOOLCHAIN}" cargo fuzz build --target "${FUZZ_TARGET}"
         working-directory: fuzz
 
       - name: Run bounded fuzz smoke for every target
@@ -57,9 +71,9 @@ jobs:
         # regression; this is not meant to be exhaustive fuzzing.
         run: |
           set -euo pipefail
-          for target in decode_request decode_open_reply decode_echo_reply decode_params decode_varint; do
+          for target in decode_request decode_open_reply decode_echo_reply decode_params decode_varint server_core_datagrams; do
             echo "::group::fuzz smoke: ${target}"
-            cargo +nightly fuzz run "${target}" -- \
+            RUSTUP_TOOLCHAIN="${FUZZ_TOOLCHAIN}" cargo fuzz run --target "${FUZZ_TARGET}" "${target}" -- \
               -max_total_time=10 \
               -timeout=5
             echo "::endgroup::"

.gitea/workflows/interop-netem.yml

@@ -32,13 +32,14 @@ jobs:
       - name: Install Rust toolchain
         uses: actions-rust-lang/setup-rust-toolchain@166cdcfd11aee3cb47222f9ddb555ce30ddb9659 # v1
         with:
-          cache-key: interop-netem
+          cache: false
 
-      - name: Check host tools
+      - name: Check host tools and network administration access
         run: |
           ip -V
           tc -V
           go version
+          sudo -n true
 
       - name: Install upstream irtt
         run: |
@@ -62,14 +63,14 @@ jobs:
         run: |
           latest_summary="$(find target/interop-netem -mindepth 2 -maxdepth 2 -name github-step-summary.md -type f -print 2>/dev/null | sort | tail -n 1)"
           if [ -n "$latest_summary" ]; then
-            cat "$latest_summary" >> "$GITHUB_STEP_SUMMARY"
+            cat "$latest_summary" >> "$GITEA_STEP_SUMMARY"
           else
-            echo "No netem interop github-step-summary.md found." >> "$GITHUB_STEP_SUMMARY"
+            echo "No netem interop github-step-summary.md found." >> "$GITEA_STEP_SUMMARY"
           fi
 
       - name: Upload netem interop artifacts
         if: always()
-        uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7
+        uses: https://gitea.com/actions/gitea-upload-artifact@v7
         with:
           name: interop-netem
           path: target/interop-netem

.gitea/workflows/semver.yml

@@ -0,0 +1,52 @@
+name: Semver
+
+on:
+  workflow_dispatch:
+  push:
+    tags:
+      - "irtt-proto/v*.*.*"
+      - "irtt-client/v*.*.*"
+      - "irtt-server/v*.*.*"
+      - "irtt-stats/v*.*.*"
+      - "irtt-rs/v*.*.*"
+
+permissions:
+  contents: read
+
+env:
+  CARGO_SEMVER_CHECKS_VERSION: 0.50.0
+  CARGO_SEMVER_CHECKS_SHA256: 52a65dc88dc53fa8b57d6087954eb52cda149ca03bcfca78ce3fdecd23f893c4
+
+jobs:
+  semver:
+    name: cargo-semver-checks
+    runs-on: ubuntu-latest
+    timeout-minutes: 20
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
+        with:
+          persist-credentials: false
+
+      - name: Install Rust toolchain
+        uses: actions-rust-lang/setup-rust-toolchain@166cdcfd11aee3cb47222f9ddb555ce30ddb9659 # v1
+        with:
+          cache: false
+
+      # The CLI preserves the previous wrapper's `feature-group: all-features`
+      # behavior without its GitHub API/cache dependency.
+      - name: Install cargo-semver-checks
+        run: |
+          set -euo pipefail
+          archive="cargo-semver-checks-x86_64-unknown-linux-gnu.tar.gz"
+          curl --fail --show-error --location --retry 3 \
+            "https://github.com/obi1kenobi/cargo-semver-checks/releases/download/v${CARGO_SEMVER_CHECKS_VERSION}/${archive}" \
+            --output "$archive"
+          echo "${CARGO_SEMVER_CHECKS_SHA256}  ${archive}" | sha256sum --check --status -
+          tar -xzf "$archive" cargo-semver-checks
+          install -Dm755 cargo-semver-checks "${RUNNER_TEMP}/bin/cargo-semver-checks"
+          echo "${RUNNER_TEMP}/bin" >> "$GITHUB_PATH"
+
+      - name: Check semver compatibility
+        run: cargo semver-checks check-release --all-features

.gitea/workflows/supply-chain.yml

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

.github/workflows/actions-security.yml

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

.github/workflows/ci-arm.yml

@@ -0,0 +1,80 @@
+name: Rust ARM CI
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+  merge_group:
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  verify:
+    name: cargo ${{ matrix.task }} (${{ matrix.target }})
+    # Gitea currently has only amd64 Linux runners; retain ARM coverage here.
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - task: check
+            target: aarch64-unknown-linux-gnu
+            musl: false
+
+          - task: test
+            target: aarch64-unknown-linux-gnu
+            musl: false
+
+          - task: check
+            target: aarch64-unknown-linux-musl
+            musl: true
+
+          - task: test
+            target: aarch64-unknown-linux-musl
+            musl: true
+
+    runs-on: ubuntu-24.04-arm
+    timeout-minutes: 25
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
+        with:
+          persist-credentials: false
+
+      - name: Install musl toolchain
+        if: matrix.musl
+        run: |
+          sudo apt-get update
+          sudo apt-get install --no-install-recommends musl-tools
+
+      - name: Install Rust toolchain
+        uses: actions-rust-lang/setup-rust-toolchain@166cdcfd11aee3cb47222f9ddb555ce30ddb9659 # v1
+        with:
+          target: ${{ matrix.target }}
+          cache-key: ${{ matrix.task }}-${{ matrix.target }}
+
+      - name: Run ${{ matrix.task }} with all features
+        run: |
+          cargo ${{ matrix.task }} \
+            --workspace \
+            --all-targets \
+            --all-features \
+            --target ${{ matrix.target }} \
+            --locked
+
+      - name: Run ${{ matrix.task }} without default features
+        run: |
+          cargo ${{ matrix.task }} \
+            --workspace \
+            --all-targets \
+            --no-default-features \
+            --target ${{ matrix.target }} \
+            --locked

.github/workflows/osv-scanner.yml

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

.github/workflows/rust-clippy.yml

@@ -60,7 +60,7 @@ jobs:
           exit 0
 
       - name: Upload Clippy SARIF
-        uses: github/codeql-action/upload-sarif@ff2f1c621b7f889edc0d3c761ac2e6a3f8cdb0dd # v4
+        uses: github/codeql-action/upload-sarif@b96794f015dfd88f77b49b1c93e0fa7110f94c63 # v4
         if: always()
         with:
           sarif_file: rust-clippy-results.sarif

.github/workflows/semver.yml

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

.github/workflows/supply-chain.yml

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

AGENTS.md

@@ -173,6 +173,7 @@ Use the narrowest useful checks first. For substantive workspace changes, final
 cargo fmt --all -- --check
 cargo check --workspace --all-targets --all-features --locked
 cargo test --workspace --all-targets --all-features --locked
+cargo test --workspace --doc --all-features --locked
 cargo clippy --workspace --all-targets --all-features --locked -- -D warnings
 ```
 

CHANGELOG.md

@@ -28,6 +28,12 @@ release. The format is loosely based on
 
 ## irtt-client
 
+### 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
@@ -102,6 +108,17 @@ release. The format is loosely based on
 
 ## irtt-rs
 
+### 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

Cargo.lock

@@ -242,7 +242,7 @@ dependencies = [
  "heck",
  "proc-macro2",
  "quote",
- "syn 3.0.3",
+ "syn 3.0.4",
 ]
 
 [[package]]
@@ -385,9 +385,9 @@ dependencies = [
 
 [[package]]
 name = "darling"
-version = "0.24.0"
+version = "0.24.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "88490bf1b990d87eaaa7ac8aa887f629a08e7359765b4911faf63c3763347d23"
+checksum = "ed17f5901b6630b993ca003def43f2f8ef4014fc13b047b57aad617ff32bc2ec"
 dependencies = [
  "darling_core",
  "darling_macro",
@@ -395,26 +395,26 @@ dependencies = [
 
 [[package]]
 name = "darling_core"
-version = "0.24.0"
+version = "0.24.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "084e274f91c482280130e1e34e0b8d6e66776a060d7b6de7b84289ca778868c4"
+checksum = "6837e2cf7485aaae18f86181d2f0e9a7ed297a025e220aeabf63fdebd3a2ddff"
 dependencies = [
  "ident_case",
  "proc-macro2",
  "quote",
  "strsim",
- "syn 3.0.3",
+ "syn 3.0.4",
 ]
 
 [[package]]
 name = "darling_macro"
-version = "0.24.0"
+version = "0.24.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "68f5792fa0d41cd2325ce0ffa64f0a340eaebd4971a3a0c5e1ffd2cc488a355e"
+checksum = "2ac7135c3ef02b2f7833bbeb1be5ba7f966dcde8a87c6b87f65a778d71a02785"
 dependencies = [
  "darling_core",
  "quote",
- "syn 3.0.3",
+ "syn 3.0.4",
 ]
 
 [[package]]
@@ -496,9 +496,9 @@ dependencies = [
 
 [[package]]
 name = "either"
-version = "1.17.0"
+version = "1.18.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9e5e8f6c15a24b9a3ee5efec809ccd006d3b30e8b3bb63c39af737c7f87daa1d"
+checksum = "252afb9ae5eaa683babdc6a068b3f5726eb19e05070c731f9b2a23a7c3e8ed34"
 
 [[package]]
 name = "equivalent"
@@ -710,12 +710,12 @@ dependencies = [
  "indoc",
  "proc-macro2",
  "quote",
- "syn 3.0.3",
+ "syn 3.0.4",
 ]
 
 [[package]]
 name = "irtt-client"
-version = "0.5.0"
+version = "0.5.1"
 dependencies = [
  "irtt-proto",
  "irtt-server",
@@ -749,7 +749,7 @@ dependencies = [
 
 [[package]]
 name = "irtt-rs"
-version = "0.6.2"
+version = "0.7.0"
 dependencies = [
  "clap",
  "crossterm",
@@ -881,15 +881,15 @@ dependencies = [
 
 [[package]]
 name = "log"
-version = "0.4.33"
+version = "0.4.34"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0ceec5bc11778974d1bcb055b18002eba7f4b3518b6a0081b3af5f21666da9ad"
+checksum = "f9f8bd3e56ce4dfc153cf470fffbfa98c7620958b312ca5c3a4b8d5181fd13c6"
 
 [[package]]
 name = "lru"
-version = "0.18.2"
+version = "0.18.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5d2f2f9b4ba7e6b24d95e7e899329d35be83bcded72c8540cdd5368932d1d90a"
+checksum = "0d317b4b9eb398e6acce275758ec6125535505e7a146fb1a9b8bda2451b0ff4c"
 dependencies = [
  "hashbrown 0.17.1",
 ]
@@ -1185,7 +1185,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3c80231409c20246a13fddb31776fb942c38553c51e871f8cbd687a4cfb5843d"
 dependencies = [
  "phf_shared",
- "rand 0.8.7",
+ "rand 0.8.8",
 ]
 
 [[package]]
@@ -1294,9 +1294,9 @@ checksum = "f8dcc9c7d52a811697d2151c701e0d08956f92b0e24136cf4cf27b57a6a0d9bf"
 
 [[package]]
 name = "rand"
-version = "0.8.7"
+version = "0.8.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "22f6172bdec972074665ed81ed53b71da00bfc44b65a753cfde883ec4c702a1a"
+checksum = "e058c7de0b26af77780c769414d6257830bb240f3c38477dbc2c16e5f54d6d4c"
 dependencies = [
  "rand_core 0.6.4",
 ]
@@ -1569,7 +1569,7 @@ checksum = "e7a5d71263a5a7d47b41f6b3f06ba276f10cc18b0931f1799f710578e2309348"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 3.0.3",
+ "syn 3.0.4",
 ]
 
 [[package]]
@@ -1705,9 +1705,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "3.0.3"
+version = "3.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "53e9bae58849f64dfa4f5d5ae372c8341f7305f82a3868709269343628b659a3"
+checksum = "e6275cddf4610d1775e6d1fe9469b2e77d0f39fd98fb7450901b821e0c53649f"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1840,7 +1840,7 @@ checksum = "bc04cd3e1236dd4a98afca4569f2deb3f120e5422a4023be2cb683f8486292af"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 3.0.3",
+ "syn 3.0.4",
 ]
 
 [[package]]
@@ -1886,7 +1886,7 @@ checksum = "78773a2a397f451582ce068015985c33193cf6dea8b74d2a639fe457b2f07b0e"
 dependencies = [
  "proc-macro2",
  "quote",
- "syn 3.0.3",
+ "syn 3.0.4",
 ]
 
 [[package]]
@@ -1944,9 +1944,9 @@ checksum = "06abde3611657adf66d383f00b093d7faecc7fa57071cce2578660c9f1010821"
 
 [[package]]
 name = "uuid"
-version = "1.24.1"
+version = "1.26.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "2cefc03fd367c0c6d4305de1b312cf00248c4114f4a0418ce6a6af769e3b0bd9"
+checksum = "b5772d71c9be8a8a6ac2117d949c5b224c1b72241bb611d9a3012edcf8af7812"
 dependencies = [
  "atomic",
  "getrandom 0.4.3",

Cargo.toml

@@ -18,7 +18,7 @@ homepage = "https://github.com/Lochnair/irtt-rs"
 
 [workspace.dependencies]
 irtt-proto = { version = "0.5.0", path = "crates/irtt-proto" }
-irtt-client = { version = "0.5.0", path = "crates/irtt-client" }
+irtt-client = { version = "0.5.1", path = "crates/irtt-client" }
 irtt-server = { version = "0.5.2", path = "crates/irtt-server" }
 irtt-stats = { version = "0.5.0", path = "crates/irtt-stats" }
 

Dockerfile

@@ -10,7 +10,7 @@
 
 FROM --platform=$BUILDPLATFORM tonistiigi/xx AS xx
 
-FROM --platform=$BUILDPLATFORM rust:1.88-alpine AS builder
+FROM --platform=$BUILDPLATFORM rust:1.98-alpine AS builder
 
 COPY --from=xx / /
 

README.md

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

crates/irtt-app/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "irtt-rs"
-version = "0.6.2"
+version = "0.7.0"
 description = "IRTT-compatible client, TUI, and server applications"
 edition.workspace = true
 license.workspace = true

crates/irtt-app/src/applet.rs

@@ -22,7 +22,7 @@ pub fn detect_applet_from_argv0(argv0: &str) -> Option<RequestedApplet> {
     match applet_basename(argv0) {
         "irtt-client" => Some(RequestedApplet::Client),
         "irtt-tui" => Some(RequestedApplet::Tui),
-        "irttd" | "irtt-server" => Some(RequestedApplet::Server),
+        "irtt-server" => Some(RequestedApplet::Server),
         "irtt-rs" => None,
         _ => None,
     }
@@ -199,6 +199,7 @@ mod tests {
             detect_applet_from_argv0("irtt-server"),
             Some(RequestedApplet::Server)
         );
+        assert_eq!(detect_applet_from_argv0("irttd"), None);
         assert_eq!(detect_applet_from_argv0("irtt-rs"), None);
         assert_eq!(detect_applet_from_argv0("custom-name"), None);
     }

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

@@ -11,15 +11,22 @@ pub const DEFAULT_CLIENT_DURATION: Duration = Duration::from_secs(10);
 #[derive(Debug, Clone, Parser)]
 #[command(name = "irtt-client", about = "Minimal IRTT-compatible stream client")]
 pub struct ClientArgs {
-    /// Server address/host, optionally prefixed with LABEL=. Repeat for multi-target mode.
+    /// Server address/host, optionally prefixed with LABEL= and suffixed with @hmac=KEY. Repeat for multi-target mode.
     #[arg(
         value_name = "TARGET",
         num_args = 0..,
         value_parser = parse_target,
-        long_help = "Server address/host, optionally prefixed with LABEL=. Repeat for multi-target mode.\n\nExamples:\n  irtt-client host-a:2112 host-b:2112\n  irtt-client eu=host-a:2112 us=host-b:2112\n  irtt-client host-a:2112 eu=host-b:2112"
+        long_help = "Server address/host, optionally prefixed with LABEL= and suffixed with @hmac=KEY. Repeat for multi-target mode.\n\nExamples:\n  irtt-client host-a:2112 host-b:2112\n  irtt-client eu=host-a:2112 us=host-b:2112\n  irtt-client ams=host-a:2112@hmac=secret public=host-b:2112@hmac=\n\nA target without @hmac= inherits --hmac. @hmac= explicitly disables it for that target."
     )]
     pub targets: Vec<TargetArg>,
 
+    /// Read complete desired target sets from standard input in continuous mode.
+    #[arg(
+        long,
+        long_help = "Read one complete desired target set per stdin line in continuous mode. Commas separate targets and backslash escapes commas within a target. [] selects an empty desired set. Records are limited to 64 KiB. EOF stops the client gracefully and may discard a revision that has not yet been acknowledged as applied."
+    )]
+    pub targets_stdin: bool,
+
     /// Managed group pacing for multi-target mode.
     #[arg(
         long,
@@ -34,7 +41,7 @@ pub struct ClientArgs {
         default_value = "10s",
         value_parser = parse_test_duration,
         help = "Test duration; use 0 for continuous mode",
-        long_help = "Test duration; use 0 for continuous mode.\n\nFinite runs retain exact statistics for final summaries. Continuous mode uses bounded-memory running statistics and prints a final summary only when interrupted."
+        long_help = "Test duration; use 0 for continuous mode.\n\nFinite runs retain exact statistics for final summaries. Continuous mode uses bounded-memory running statistics and prints a final summary when interrupted; --targets-stdin also prints the final retained summary on EOF."
     )]
     pub duration: Duration,
 
@@ -86,12 +93,16 @@ impl ClientArgs {
     /// Targets are only required here. `--list-columns` returns before this is
     /// called, so listing columns still needs no target.
     pub fn prepare(&self) -> Result<ManagedRunSetup, String> {
+        if self.targets_stdin && !self.is_continuous() {
+            return Err("--targets-stdin requires --duration 0".to_owned());
+        }
         prepare_managed_run(
             &self.common,
             self.duration,
             TargetSelection {
                 targets: &self.targets,
                 pacing: self.pacing,
+                stdin_controlled: self.targets_stdin,
             },
         )
     }
@@ -159,14 +170,14 @@ mod tests {
         let args = parse(&["127.0.0.1:2112"]).unwrap();
 
         assert_eq!(args.targets.len(), 1);
-        assert_eq!(args.targets[0].label, None);
+        assert_eq!(args.prepare().unwrap().targets[0].label, "127.0.0.1:2112");
-        assert_eq!(args.targets[0].addr, "127.0.0.1:2112");
         assert_eq!(args.pacing, GroupPacingArg::Staggered);
         assert_eq!(args.duration, DEFAULT_CLIENT_DURATION);
         assert_eq!(args.interval, Duration::from_secs(1));
         assert_eq!(args.format, OutputFormat::Table);
         assert_eq!(args.columns, None);
         assert_eq!(args.header, HeaderMode::Auto);
+        assert!(!args.targets_stdin);
         assert!(!args.is_continuous());
         assert_eq!(args.timestamp_mode(), TimestampArg::Both);
 
@@ -254,8 +265,8 @@ mod tests {
 
     #[test]
     fn invalid_labelled_target_syntax_is_rejected() {
-        assert!(parse(&["=127.0.0.1:2112"]).is_err());
+        assert!(parse(&["=127.0.0.1:2112"]).unwrap().prepare().is_err());
-        assert!(parse(&["label="]).is_err());
+        assert!(parse(&["label="]).unwrap().prepare().is_err());
     }
 
     #[test]
@@ -309,6 +320,21 @@ mod tests {
         assert_eq!(config.hmac_key, Some(b"secret".to_vec()));
     }
 
+    #[test]
+    fn targets_stdin_requires_continuous_mode_and_allows_empty_initial_set() {
+        assert!(parse(&["--targets-stdin"]).unwrap().prepare().is_err());
+        let args = parse(&["--duration", "0", "--targets-stdin"]).unwrap();
+        let setup = args.prepare().unwrap();
+        assert!(setup.targets.is_empty());
+        assert!(setup.stdin_controlled);
+        let config = setup.managed_config();
+        assert_eq!(
+            config.completion,
+            irtt_client::managed::ManagedCompletionPolicy::ExplicitStop
+        );
+        assert_eq!(config.max_live_target_generations, 256);
+    }
+
     #[test]
     fn output_format_summary_policy_is_table_only() {
         assert!(OutputFormat::Table.prints_summary());

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

@@ -1,16 +1,16 @@
-use std::collections::BTreeMap;
 use std::{
-    collections::HashSet,
+    collections::{BTreeMap, BTreeSet, HashSet, VecDeque},
-    io::{self, Write},
+    io::{self, BufRead, Write},
-    sync::atomic::AtomicBool,
+    sync::{atomic::AtomicBool, Arc, Mutex},
     thread,
     time::Duration,
 };
 
 use irtt_client::{
     managed::{
-        BlockingManagedClient, ManagedEndReason, ManagedEvent, ManagedEventSubscription,
+        BlockingManagedClient, ManagedClientHandle, ManagedCommandApplyError, ManagedEndReason,
-        ManagedEventTryRecvError, ManagedTargetEndReason, ManagedTargetOutcome, TargetInstance,
+        ManagedEvent, ManagedEventSubscription, ManagedEventTryRecvError, ManagedStatus,
+        ManagedTargetConfig, ManagedTargetEndReason, ManagedTargetOutcome, TargetInstance,
     },
     ClientEvent,
 };
@@ -20,13 +20,13 @@ use super::{
     output::{EventRenderStats, OutputConfig},
 };
 
-use crate::shared::client::expected_probe_count;
 use crate::shared::client::{
-    is_shutdown_requested,
+    expected_probe_count, is_shutdown_requested, parse_stdin_target_set,
     session::{
         drain_managed_events, peer_close_run_error, request_managed_stop_for_peer_close,
         request_managed_stop_once, should_print_final_summary, ManagedDrainState,
     },
+    ManagedRunSetup, STDIN_MAX_DESIRED_TARGETS, STDIN_OUTCOME_HISTORY_LIMIT,
 };
 
 use irtt_stats::{StatsCollector, StatsConfig};
@@ -41,6 +41,7 @@ const FINITE_STATS_MEMORY_STRONG_WARNING_BYTES: u64 = 512 * MIB;
 
 const FINITE_STATS_MEMORY_VERY_STRONG_WARNING_BYTES: u64 = GIB;
 const MANAGED_EVENT_WAIT_SLICE: Duration = Duration::from_millis(20);
+const MAX_STDIN_RECORD_BYTES: usize = 64 * 1024;
 
 pub fn run_stream(
     args: ClientArgs,
@@ -61,6 +62,9 @@ pub fn run_stream(
         args.verbose,
     )
     .map_err(|err| io::Error::new(io::ErrorKind::InvalidInput, err))?;
+    if setup.stdin_controlled {
+        return run_stdin_stream(setup, output_config, shutdown_requested);
+    }
     let continuous = args.is_continuous();
     let target_count = setup.target_count();
 
@@ -196,6 +200,561 @@ pub fn run_stream(
     Ok(())
 }
 
+#[derive(Clone)]
+struct StdinTargetSet {
+    revision: u64,
+    targets: Vec<ManagedTargetConfig>,
+}
+
+#[derive(Default)]
+struct StdinMailboxState {
+    next_revision: u64,
+    latest: Option<StdinTargetSet>,
+    eof: bool,
+    fatal: Option<String>,
+}
+
+#[derive(Default)]
+struct StdinMailbox {
+    state: Mutex<StdinMailboxState>,
+}
+
+impl StdinMailbox {
+    fn publish(&self, targets: Vec<ManagedTargetConfig>) {
+        let mut state = self
+            .state
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner);
+        state.next_revision = state.next_revision.saturating_add(1);
+        state.latest = Some(StdinTargetSet {
+            revision: state.next_revision,
+            targets,
+        });
+    }
+
+    fn finish(&self) {
+        self.state
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner)
+            .eof = true;
+    }
+
+    fn fail(&self, error: String) {
+        let mut state = self
+            .state
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner);
+        state.fatal = Some(error);
+        state.latest = None;
+    }
+
+    fn latest(&self) -> Option<StdinTargetSet> {
+        self.state
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner)
+            .latest
+            .clone()
+    }
+
+    fn clear_if_current(&self, revision: u64) {
+        let mut state = self
+            .state
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner);
+        if state
+            .latest
+            .as_ref()
+            .is_some_and(|set| set.revision == revision)
+        {
+            state.latest = None;
+        }
+    }
+
+    fn is_current(&self, revision: u64) -> bool {
+        self.state
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner)
+            .latest
+            .as_ref()
+            .is_some_and(|set| set.revision == revision)
+    }
+
+    fn fatal(&self) -> Option<String> {
+        self.state
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner)
+            .fatal
+            .clone()
+    }
+
+    fn is_finished(&self) -> bool {
+        self.state
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner)
+            .eof
+    }
+}
+
+fn read_stdin_record<R: BufRead>(
+    reader: &mut R,
+    buffer: &mut Vec<u8>,
+) -> io::Result<Option<String>> {
+    buffer.clear();
+    loop {
+        let available = reader.fill_buf()?;
+        if available.is_empty() {
+            if buffer.is_empty() {
+                return Ok(None);
+            }
+            if buffer.len() > MAX_STDIN_RECORD_BYTES {
+                return Err(io::Error::new(
+                    io::ErrorKind::InvalidData,
+                    "stdin target record exceeds the maximum size",
+                ));
+            }
+            return std::str::from_utf8(buffer)
+                .map(str::to_owned)
+                .map(Some)
+                .map_err(|_| io::Error::new(io::ErrorKind::InvalidData, "stdin is not UTF-8"));
+        }
+
+        if buffer.len() == MAX_STDIN_RECORD_BYTES + 1 {
+            if available.first() == Some(&b'\n') && buffer.last() == Some(&b'\r') {
+                reader.consume(1);
+                buffer.pop();
+                return std::str::from_utf8(buffer)
+                    .map(str::to_owned)
+                    .map(Some)
+                    .map_err(|_| io::Error::new(io::ErrorKind::InvalidData, "stdin is not UTF-8"));
+            }
+            return Err(io::Error::new(
+                io::ErrorKind::InvalidData,
+                "stdin target record exceeds the maximum size",
+            ));
+        }
+
+        if let Some(newline) = available.iter().position(|byte| *byte == b'\n') {
+            let before_newline = &available[..newline];
+            if buffer.len().saturating_add(before_newline.len()) > MAX_STDIN_RECORD_BYTES + 1 {
+                return Err(io::Error::new(
+                    io::ErrorKind::InvalidData,
+                    "stdin target record exceeds the maximum size",
+                ));
+            }
+            buffer.extend_from_slice(before_newline);
+            reader.consume(newline + 1);
+            if buffer.last() == Some(&b'\r') {
+                buffer.pop();
+            }
+            if buffer.len() > MAX_STDIN_RECORD_BYTES {
+                return Err(io::Error::new(
+                    io::ErrorKind::InvalidData,
+                    "stdin target record exceeds the maximum size",
+                ));
+            }
+            return std::str::from_utf8(buffer)
+                .map(str::to_owned)
+                .map(Some)
+                .map_err(|_| io::Error::new(io::ErrorKind::InvalidData, "stdin is not UTF-8"));
+        }
+
+        let remaining = MAX_STDIN_RECORD_BYTES + 1 - buffer.len();
+        let take = available.len().min(remaining);
+        buffer.extend_from_slice(&available[..take]);
+        reader.consume(take);
+        if buffer.len() > MAX_STDIN_RECORD_BYTES && buffer.last() != Some(&b'\r') {
+            return Err(io::Error::new(
+                io::ErrorKind::InvalidData,
+                "stdin target record exceeds the maximum size",
+            ));
+        }
+    }
+}
+
+fn read_stdin_target_sets<R: BufRead>(reader: &mut R, mailbox: &StdinMailbox) {
+    let mut line = 0_u64;
+    let mut record = Vec::with_capacity(MAX_STDIN_RECORD_BYTES + 1);
+    loop {
+        match read_stdin_record(reader, &mut record) {
+            Ok(Some(record)) => {
+                line = line.saturating_add(1);
+                if record.is_empty() {
+                    continue;
+                }
+                match parse_stdin_target_set(&record, STDIN_MAX_DESIRED_TARGETS) {
+                    Ok(targets) => {
+                        mailbox.publish(targets.into_iter().map(|target| target.managed).collect())
+                    }
+                    Err(error) => {
+                        mailbox.fail(format!("invalid --targets-stdin line {line}: {error}"));
+                        return;
+                    }
+                }
+            }
+            Ok(None) => {
+                mailbox.finish();
+                return;
+            }
+            Err(_) => {
+                mailbox.fail(format!("failed to read --targets-stdin line {}", line + 1));
+                return;
+            }
+        }
+    }
+}
+
+fn spawn_stdin_target_reader(mailbox: Arc<StdinMailbox>) -> io::Result<()> {
+    thread::Builder::new()
+        .name("irtt-targets-stdin".to_owned())
+        .spawn(move || {
+            let stdin = io::stdin();
+            read_stdin_target_sets(&mut stdin.lock(), &mailbox);
+        })
+        .map(|_| ())
+}
+
+#[derive(Clone)]
+struct RetryAfterStatus {
+    revision: u64,
+    status: Arc<ManagedStatus>,
+}
+
+fn retry_waits_for_status_change(
+    retry_after: &mut Option<RetryAfterStatus>,
+    target_set: &StdinTargetSet,
+    status: &Arc<ManagedStatus>,
+) -> bool {
+    let Some(retry) = retry_after else {
+        return false;
+    };
+    if retry.revision != target_set.revision {
+        *retry_after = None;
+        return false;
+    }
+    Arc::ptr_eq(&retry.status, status)
+}
+
+fn retry_after_capacity_rejection(
+    mailbox: &StdinMailbox,
+    target_set: &StdinTargetSet,
+    status: Arc<ManagedStatus>,
+) -> Option<RetryAfterStatus> {
+    mailbox
+        .is_current(target_set.revision)
+        .then_some(RetryAfterStatus {
+            revision: target_set.revision,
+            status,
+        })
+}
+
+fn apply_latest_stdin_target_set(
+    handle: &ManagedClientHandle,
+    mailbox: &StdinMailbox,
+    retry_after: &mut Option<RetryAfterStatus>,
+) -> Result<(), String> {
+    let Some(target_set) = mailbox.latest() else {
+        *retry_after = None;
+        return Ok(());
+    };
+    let status = handle.status();
+    if retry_waits_for_status_change(retry_after, &target_set, &status) {
+        return Ok(());
+    }
+
+    let receipt = handle
+        .update_targets(target_set.targets.clone())
+        .map_err(|_| "failed to submit --targets-stdin update".to_owned())?;
+    match receipt.blocking_wait() {
+        Ok(_) => {
+            mailbox.clear_if_current(target_set.revision);
+            *retry_after = None;
+            Ok(())
+        }
+        Err(ManagedCommandApplyError::LiveGenerationLimitExceeded { .. }) => {
+            *retry_after = retry_after_capacity_rejection(mailbox, &target_set, status);
+            Ok(())
+        }
+        Err(_) => Err("--targets-stdin update was rejected".to_owned()),
+    }
+}
+
+struct BoundedTargetSet {
+    limit: usize,
+    order: VecDeque<TargetInstance>,
+    members: HashSet<TargetInstance>,
+}
+
+impl BoundedTargetSet {
+    fn new(limit: usize) -> Self {
+        Self {
+            limit,
+            order: VecDeque::with_capacity(limit),
+            members: HashSet::with_capacity(limit),
+        }
+    }
+
+    fn insert(&mut self, target: TargetInstance) -> bool {
+        if !self.members.insert(target.clone()) {
+            return false;
+        }
+        if self.order.len() == self.limit {
+            let evicted = self
+                .order
+                .pop_front()
+                .expect("bounded target order is nonempty");
+            self.members.remove(&evicted);
+        }
+        self.order.push_back(target);
+        true
+    }
+}
+
+fn process_stdin_event<W: Write>(
+    event: ManagedEvent,
+    stream_output: &mut StreamOutput<'_, W>,
+    stats: &mut BTreeMap<TargetInstance, StatsCollector>,
+    terminal_targets: &mut BoundedTargetSet,
+) -> io::Result<()> {
+    match event {
+        ManagedEvent::TargetStateChanged { target, .. } => {
+            stats
+                .entry(target)
+                .or_insert_with(|| StatsCollector::new(stats_config(true)));
+        }
+        ManagedEvent::Client { target, event } => {
+            let collector = stats
+                .entry(target.clone())
+                .or_insert_with(|| StatsCollector::new(stats_config(true)));
+            print_events_with_stats(
+                stream_output,
+                std::slice::from_ref(&event),
+                Some(target.id.as_str()),
+                collector,
+            )?;
+        }
+        ManagedEvent::TargetFinished { outcome }
+            if terminal_targets.insert(outcome.target.clone()) =>
+        {
+            report_target_failure(&outcome);
+        }
+        _ => {}
+    }
+    Ok(())
+}
+
+fn drain_stdin_events<W: Write>(
+    events: &mut ManagedEventSubscription,
+    stream_output: &mut StreamOutput<'_, W>,
+    stats: &mut BTreeMap<TargetInstance, StatsCollector>,
+    terminal_targets: &mut BoundedTargetSet,
+    dropped_events: &mut u64,
+) -> io::Result<ManagedDrainState> {
+    drain_managed_events(events, dropped_events, |event| {
+        process_stdin_event(event, stream_output, stats, terminal_targets)
+    })
+}
+
+fn drain_final_stdin_events<W: Write>(
+    events: &mut ManagedEventSubscription,
+    stream_output: &mut StreamOutput<'_, W>,
+    stats: &mut BTreeMap<TargetInstance, StatsCollector>,
+    terminal_targets: &mut BoundedTargetSet,
+    dropped_events: &mut u64,
+) -> io::Result<()> {
+    loop {
+        match events.try_recv() {
+            Ok(event) => process_stdin_event(event, stream_output, stats, terminal_targets)?,
+            Err(ManagedEventTryRecvError::Empty | ManagedEventTryRecvError::Closed) => break,
+            Err(ManagedEventTryRecvError::Lagged(count)) => {
+                *dropped_events = dropped_events.saturating_add(count);
+            }
+        }
+    }
+    Ok(())
+}
+
+fn reconcile_stdin_stats(
+    stats: &mut BTreeMap<TargetInstance, StatsCollector>,
+    status: &ManagedStatus,
+    final_summary_targets: Option<&BTreeSet<TargetInstance>>,
+) {
+    let live = status
+        .targets
+        .iter()
+        .map(|target| target.target.clone())
+        .collect::<HashSet<_>>();
+    stats.retain(|target, _| {
+        live.contains(target)
+            || final_summary_targets.is_some_and(|targets| targets.contains(target))
+    });
+}
+
+fn snapshot_stdin_summary_targets(
+    stats: &mut BTreeMap<TargetInstance, StatsCollector>,
+    status: &ManagedStatus,
+) -> BTreeSet<TargetInstance> {
+    let targets = status
+        .targets
+        .iter()
+        .map(|target| target.target.clone())
+        .collect::<BTreeSet<_>>();
+    for target in &targets {
+        stats
+            .entry(target.clone())
+            .or_insert_with(|| StatsCollector::new(stats_config(true)));
+    }
+    targets
+}
+
+#[derive(Clone)]
+enum StdinStop {
+    Interrupted,
+    Eof,
+    Fatal(String),
+}
+
+fn stdin_stop_request(
+    shutdown_requested: &AtomicBool,
+    mailbox: &StdinMailbox,
+) -> Option<StdinStop> {
+    if is_shutdown_requested(shutdown_requested) {
+        Some(StdinStop::Interrupted)
+    } else if let Some(error) = mailbox.fatal() {
+        Some(StdinStop::Fatal(error))
+    } else if mailbox.is_finished() {
+        Some(StdinStop::Eof)
+    } else {
+        None
+    }
+}
+
+fn run_stdin_stream(
+    setup: ManagedRunSetup,
+    output_config: OutputConfig,
+    shutdown_requested: &AtomicBool,
+) -> Result<(), Box<dyn std::error::Error>> {
+    if is_shutdown_requested(shutdown_requested) {
+        return Ok(());
+    }
+    let (owner, mut events) = BlockingManagedClient::start_with_subscription(
+        setup.managed_config(),
+        setup.managed_targets(),
+    )?;
+    let handle = owner.handle();
+    let mailbox = Arc::new(StdinMailbox::default());
+    spawn_stdin_target_reader(Arc::clone(&mailbox))?;
+
+    let mut stdout = io::LineWriter::new(io::stdout().lock());
+    let mut stream_output = StreamOutput {
+        config: output_config,
+        header_printed: false,
+        print_final_summary: false,
+        show_running_only_summary_note: false,
+        out: &mut stdout,
+    };
+    let mut stats = BTreeMap::new();
+    let mut terminal_targets = BoundedTargetSet::new(STDIN_OUTCOME_HISTORY_LIMIT);
+    let mut retry_after = None;
+    let mut dropped_events = 0_u64;
+    let mut stop_requested = false;
+    let mut stop = None;
+    let mut summary_targets = None;
+    let mut subscription_closed = false;
+
+    loop {
+        let status = handle.status();
+        if stop.is_none() {
+            if let Some(requested_stop) = stdin_stop_request(shutdown_requested, &mailbox) {
+                summary_targets = Some(snapshot_stdin_summary_targets(&mut stats, &status));
+                stop = Some(requested_stop);
+                if request_managed_stop_once(&mut stop_requested) {
+                    drop(handle.stop());
+                }
+            } else if let Err(error) =
+                apply_latest_stdin_target_set(&handle, &mailbox, &mut retry_after)
+            {
+                summary_targets = Some(snapshot_stdin_summary_targets(&mut stats, &status));
+                stop = Some(StdinStop::Fatal(error));
+                if request_managed_stop_once(&mut stop_requested) {
+                    drop(handle.stop());
+                }
+            }
+        }
+
+        let drain_state = drain_stdin_events(
+            &mut events,
+            &mut stream_output,
+            &mut stats,
+            &mut terminal_targets,
+            &mut dropped_events,
+        )?;
+        reconcile_stdin_stats(&mut stats, &handle.status(), summary_targets.as_ref());
+        match drain_state {
+            ManagedDrainState::Empty => thread::sleep(MANAGED_EVENT_WAIT_SLICE),
+            ManagedDrainState::Closed => subscription_closed = true,
+            ManagedDrainState::BudgetExhausted => {}
+        }
+        if handle.status().final_outcome.is_some() || subscription_closed {
+            break;
+        }
+    }
+
+    let outcome = owner.join()?;
+    drain_final_stdin_events(
+        &mut events,
+        &mut stream_output,
+        &mut stats,
+        &mut terminal_targets,
+        &mut dropped_events,
+    )?;
+    if let Some(warning) = dropped_event_warning(dropped_events) {
+        eprintln!("{warning}");
+    }
+    for target in outcome.recent_target_outcomes.iter() {
+        if terminal_targets.insert(target.target.clone()) {
+            report_target_failure(target);
+        }
+    }
+    if outcome.discarded_target_outcomes != 0 {
+        eprintln!(
+            "irtt-rs: warning: {} final target outcomes were discarded",
+            outcome.discarded_target_outcomes
+        );
+    }
+
+    let print_summary = matches!(stop, Some(StdinStop::Interrupted | StdinStop::Eof));
+    stream_output.print_final_summary = print_summary;
+    stream_output.show_running_only_summary_note = print_summary;
+    if let Some(summary_targets) = summary_targets {
+        let multi_target = summary_targets.len() > 1;
+        for target in summary_targets {
+            let stats = stats
+                .get(&target)
+                .expect("summary snapshot retains every selected target collector");
+            if multi_target && stream_output.config.prints_summary() {
+                writeln!(stream_output.out)?;
+                writeln!(
+                    stream_output.out,
+                    "target: {} (generation {})",
+                    target.id, target.generation
+                )?;
+            }
+            stream_output.print_summary(stats)?;
+        }
+    }
+    stream_output.out.flush()?;
+
+    match stop {
+        Some(StdinStop::Fatal(error)) => Err(error.into()),
+        _ => match outcome.end_reason {
+            ManagedEndReason::DriverFailed(failure) => {
+                Err(format!("managed driver failed: {failure}").into())
+            }
+            _ => Ok(()),
+        },
+    }
+}
+
 fn process_event<W: Write>(
     event: ManagedEvent,
     stream_output: &mut StreamOutput<'_, W>,
@@ -384,9 +943,218 @@ fn finite_stats_memory_warning(args: &ClientArgs, target_count: usize) -> Option
 mod tests {
     use super::*;
     use irtt_client::managed::{
-        ManagedTargetFailure, ManagedTargetFailureKind, ManagedTargetFailurePhase, TargetId,
+        ManagedLifecycle, ManagedTargetFailure, ManagedTargetFailureKind,
+        ManagedTargetFailurePhase, ManagedTargetLifecycle, ManagedTargetStatus, TargetId,
     };
-    use std::sync::Arc;
+    use std::{io::BufReader, io::Cursor, sync::Arc};
+
+    #[test]
+    fn stdin_record_reader_removes_only_line_framing() {
+        let mut reader = BufReader::with_capacity(2, Cursor::new(b" first \r\n\nthird\r"));
+        let mut buffer = Vec::with_capacity(MAX_STDIN_RECORD_BYTES + 1);
+
+        assert_eq!(
+            read_stdin_record(&mut reader, &mut buffer).unwrap(),
+            Some(" first ".to_owned())
+        );
+        assert_eq!(
+            read_stdin_record(&mut reader, &mut buffer).unwrap(),
+            Some(String::new())
+        );
+        assert_eq!(
+            read_stdin_record(&mut reader, &mut buffer).unwrap(),
+            Some("third\r".to_owned())
+        );
+        assert_eq!(read_stdin_record(&mut reader, &mut buffer).unwrap(), None);
+    }
+
+    #[test]
+    fn stdin_record_reader_rejects_over_limit_unterminated_record() {
+        let input = vec![b'x'; MAX_STDIN_RECORD_BYTES + 1];
+        let mut reader = BufReader::with_capacity(17, Cursor::new(input));
+        let mut buffer = Vec::with_capacity(MAX_STDIN_RECORD_BYTES + 1);
+
+        let error = read_stdin_record(&mut reader, &mut buffer).unwrap_err();
+        assert_eq!(error.kind(), io::ErrorKind::InvalidData);
+        assert!(error.to_string().contains("maximum size"));
+        assert!(buffer.len() <= MAX_STDIN_RECORD_BYTES + 1);
+    }
+
+    #[test]
+    fn newer_mailbox_value_survives_an_earlier_submitted_acknowledgement() {
+        let mailbox = StdinMailbox::default();
+        mailbox.publish(vec![ManagedTargetConfig::new("a", "127.0.0.1:2112")]);
+        let submitted = mailbox.latest().unwrap();
+        mailbox.publish(vec![ManagedTargetConfig::new("b", "127.0.0.1:2113")]);
+        let pending = mailbox.latest().unwrap();
+
+        mailbox.clear_if_current(submitted.revision);
+
+        assert_eq!(mailbox.latest().unwrap().revision, pending.revision);
+    }
+
+    #[test]
+    fn rejected_update_retries_after_status_publishes_during_acknowledgement() {
+        let mailbox = StdinMailbox::default();
+        mailbox.publish(Vec::new());
+        let target_set = mailbox.latest().unwrap();
+        let saturated = Arc::new(status_with_targets(&[TargetInstance {
+            id: TargetId::from("old"),
+            generation: 1,
+        }]));
+        let capacity_freed = Arc::new(status_with_targets(&[]));
+        // Capacity becomes available after the transaction rejected but before
+        // its acknowledgement reaches the controller. The rejection path must
+        // retain the pre-submission status, not this later snapshot.
+        let mut retry_after =
+            retry_after_capacity_rejection(&mailbox, &target_set, Arc::clone(&saturated));
+
+        assert!(retry_waits_for_status_change(
+            &mut retry_after,
+            &target_set,
+            &saturated
+        ));
+        assert!(!retry_waits_for_status_change(
+            &mut retry_after,
+            &target_set,
+            &capacity_freed
+        ));
+    }
+
+    #[test]
+    fn later_desired_set_supersedes_a_capacity_rejected_candidate_before_retry() {
+        let mailbox = StdinMailbox::default();
+        mailbox.publish(vec![ManagedTargetConfig::new("a", "127.0.0.1:2112")]);
+        let applied = mailbox.latest().unwrap();
+        mailbox.clear_if_current(applied.revision);
+
+        mailbox.publish(vec![ManagedTargetConfig::new("b", "127.0.0.1:2113")]);
+        let rejected = mailbox.latest().unwrap();
+        let saturated = Arc::new(status_with_targets(&[TargetInstance {
+            id: TargetId::from("old"),
+            generation: 1,
+        }]));
+        let mut retry_after = retry_after_capacity_rejection(&mailbox, &rejected, saturated);
+        mailbox.publish(vec![ManagedTargetConfig::new("c", "127.0.0.1:2114")]);
+        let replacement = mailbox.latest().unwrap();
+
+        assert!(!retry_waits_for_status_change(
+            &mut retry_after,
+            &replacement,
+            &Arc::new(status_with_targets(&[TargetInstance {
+                id: TargetId::from("old"),
+                generation: 1,
+            }]))
+        ));
+        assert!(retry_after.is_none());
+        assert_eq!(replacement.targets[0].id.as_str(), "c");
+        mailbox.clear_if_current(replacement.revision);
+        assert!(mailbox.latest().is_none());
+    }
+
+    #[test]
+    fn eof_and_shutdown_stop_without_waiting_for_the_stdin_reader() {
+        let mailbox = StdinMailbox::default();
+        let shutdown_requested = AtomicBool::new(false);
+        assert!(stdin_stop_request(&shutdown_requested, &mailbox).is_none());
+
+        mailbox.finish();
+        assert!(matches!(
+            stdin_stop_request(&shutdown_requested, &mailbox),
+            Some(StdinStop::Eof)
+        ));
+
+        let mailbox = StdinMailbox::default();
+        shutdown_requested.store(true, std::sync::atomic::Ordering::Relaxed);
+        assert!(matches!(
+            stdin_stop_request(&shutdown_requested, &mailbox),
+            Some(StdinStop::Interrupted)
+        ));
+    }
+
+    fn status_with_targets(targets: &[TargetInstance]) -> ManagedStatus {
+        ManagedStatus {
+            lifecycle: ManagedLifecycle::Running,
+            stop_requested: false,
+            applied_command_sequence: 0,
+            desired_target_count: targets.len(),
+            connecting_target_count: 0,
+            opening_target_count: 0,
+            active_target_count: 0,
+            draining_target_count: 0,
+            closing_target_count: 0,
+            terminal_target_count: 0,
+            total_target_outcomes: 0,
+            successful_target_outcomes: 0,
+            failed_target_outcomes: 0,
+            peer_closed_target_outcomes: 0,
+            discarded_target_outcomes: 0,
+            targets: Arc::from(
+                targets
+                    .iter()
+                    .cloned()
+                    .map(|target| ManagedTargetStatus {
+                        target,
+                        desired: true,
+                        lifecycle: ManagedTargetLifecycle::Active,
+                        server_addr: Arc::from("127.0.0.1:2112"),
+                        remote: None,
+                    })
+                    .collect::<Vec<_>>()
+                    .into_boxed_slice(),
+            ),
+            recent_target_outcomes: Arc::from([]),
+            final_outcome: None,
+        }
+    }
+
+    #[test]
+    fn dynamic_accounting_prunes_retired_generations_and_retains_only_shutdown_snapshot() {
+        let retired = TargetInstance {
+            id: TargetId::from("edge"),
+            generation: 1,
+        };
+        let replacement = TargetInstance {
+            id: TargetId::from("edge"),
+            generation: 2,
+        };
+        let live_status = status_with_targets(std::slice::from_ref(&replacement));
+        let empty_status = status_with_targets(&[]);
+        let mut stats = BTreeMap::from([
+            (retired.clone(), StatsCollector::new(stats_config(true))),
+            (replacement.clone(), StatsCollector::new(stats_config(true))),
+        ]);
+
+        reconcile_stdin_stats(&mut stats, &live_status, None);
+        assert_eq!(stats.keys().cloned().collect::<Vec<_>>(), [replacement]);
+
+        let summary_targets = snapshot_stdin_summary_targets(&mut stats, &live_status);
+        stats.insert(retired, StatsCollector::new(stats_config(true)));
+        reconcile_stdin_stats(&mut stats, &empty_status, Some(&summary_targets));
+
+        assert_eq!(
+            stats.keys().cloned().collect::<Vec<_>>(),
+            [TargetInstance {
+                id: TargetId::from("edge"),
+                generation: 2,
+            }]
+        );
+    }
+
+    #[test]
+    fn terminal_deduplication_is_bounded_under_target_churn() {
+        let mut terminal_targets = BoundedTargetSet::new(2);
+        let target = |generation| TargetInstance {
+            id: TargetId::from("edge"),
+            generation,
+        };
+
+        assert!(terminal_targets.insert(target(1)));
+        assert!(terminal_targets.insert(target(2)));
+        assert!(terminal_targets.insert(target(3)));
+        assert!(terminal_targets.insert(target(1)));
+        assert!(!terminal_targets.insert(target(3)));
+    }
 
     fn long_finite_args() -> ClientArgs {
         use clap::Parser;

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

@@ -106,10 +106,22 @@ pub struct ServerArgs {
     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",
-        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."
+        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,
 }
@@ -548,6 +560,43 @@ mod tests {
         );
     }
 
+    /// `IRTT_SERVER_NO_DSCP` is the one policy variable whose value is a
+    /// boolean rather than a number, a duration or a string, and the
+    /// container/orchestrator deployments this whole environment surface
+    /// exists for spell booleans `1`/`0`. clap's default parser for a flag
+    /// accepts only the literals `true`/`false` and turns everything else
+    /// into a *parse failure*, so `IRTT_SERVER_NO_DSCP=1` used to stop the
+    /// server from starting at all rather than enabling the flag. Falsey
+    /// semantics are what keeps that from being a startup failure.
+    #[test]
+    fn the_no_dscp_environment_variable_accepts_ordinary_boolean_spellings() {
+        for value in ["1", "true", "TRUE", "yes", "on", "enabled"] {
+            with_env(&[("IRTT_SERVER_NO_DSCP", value)], || {
+                let config = parse(&["--bind", "127.0.0.1:2112"])
+                    .expect("a truthy value must not fail argument parsing")
+                    .server_config();
+                assert!(!config.dscp_allowed(), "IRTT_SERVER_NO_DSCP={value}");
+            });
+        }
+
+        for value in ["0", "false", "no", "off", ""] {
+            with_env(&[("IRTT_SERVER_NO_DSCP", value)], || {
+                let config = parse(&["--bind", "127.0.0.1:2112"])
+                    .expect("a falsey value must not fail argument parsing")
+                    .server_config();
+                assert!(config.dscp_allowed(), "IRTT_SERVER_NO_DSCP={value}");
+            });
+        }
+    }
+
+    /// The command-line flag stays a flag: it takes no value, whatever the
+    /// environment parser accepts.
+    #[test]
+    fn the_no_dscp_flag_still_takes_no_command_line_value() {
+        assert!(parse(&["--bind", "127.0.0.1:2112", "--no-dscp=false"]).is_err());
+        assert!(!bound(&["--no-dscp"]).server_config().dscp_allowed());
+    }
+
     #[test]
     fn an_explicit_flag_overrides_the_environment() {
         with_env(&[("IRTT_SERVER_MAX_SESSIONS", "512")], || {

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

@@ -14,13 +14,13 @@ pub const DEFAULT_TUI_DURATION: Duration = Duration::ZERO;
 #[derive(Debug, Clone, Parser)]
 #[command(name = "irtt-tui", about = "Minimal IRTT-compatible TUI client")]
 pub struct TuiArgs {
-    /// Server address/host, optionally prefixed with LABEL=. Repeat for multi-target mode.
+    /// Server address/host, optionally prefixed with LABEL= and suffixed with @hmac=KEY. Repeat for multi-target mode.
     #[arg(
         value_name = "TARGET",
         num_args = 1..,
         required = true,
         value_parser = parse_target,
-        long_help = "Server address/host, optionally prefixed with LABEL=. Repeat for multi-target mode.\n\nExplicit labels are used in the legend and status table.\n\nExamples:\n  irtt-tui host.example\n  irtt-tui eu=host.example\n  irtt-tui eu=host-a.example us=host-b.example"
+        long_help = "Server address/host, optionally prefixed with LABEL= and suffixed with @hmac=KEY. Repeat for multi-target mode.\n\nExplicit labels are used in the legend and status table. A target without @hmac= inherits --hmac; @hmac= disables it for that target.\n\nExamples:\n  irtt-tui host.example\n  irtt-tui eu=host.example\n  irtt-tui eu=host-a.example@hmac=secret us=host-b.example"
     )]
     pub targets: Vec<TargetArg>,
 
@@ -58,6 +58,7 @@ impl TuiArgs {
             TargetSelection {
                 targets: &self.targets,
                 pacing: self.pacing,
+                stdin_controlled: false,
             },
         )
     }
@@ -107,8 +108,7 @@ mod tests {
     fn tui_parser_defaults_to_continuous_and_has_no_output_option() {
         let args = parse(&["127.0.0.1:2112"]).unwrap();
         assert_eq!(args.targets.len(), 1);
-        assert_eq!(args.targets[0].label, None);
+        assert_eq!(args.prepare().unwrap().targets[0].label, "127.0.0.1:2112");
-        assert_eq!(args.targets[0].addr, "127.0.0.1:2112");
         assert_eq!(args.pacing, GroupPacingArg::Staggered);
         assert_eq!(args.duration, DEFAULT_TUI_DURATION);
         assert!(args.is_continuous());
@@ -181,8 +181,8 @@ mod tests {
 
     #[test]
     fn invalid_labelled_target_syntax_is_rejected() {
-        assert!(parse(&["=127.0.0.1:2112"]).is_err());
+        assert!(parse(&["=127.0.0.1:2112"]).unwrap().prepare().is_err());
-        assert!(parse(&["label="]).is_err());
+        assert!(parse(&["label="]).unwrap().prepare().is_err());
     }
 
     #[test]

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

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

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

@@ -22,6 +22,9 @@ use super::{
 
 /// Capacity of the lossy managed presentation event channel.
 pub const MANAGED_EVENT_CAPACITY: usize = 16_384;
+pub const STDIN_MAX_DESIRED_TARGETS: usize = 128;
+pub const STDIN_MAX_LIVE_TARGET_GENERATIONS: usize = 256;
+pub const STDIN_OUTCOME_HISTORY_LIMIT: usize = 256;
 
 /// Target and pacing arguments common to the client applets.
 ///
@@ -31,6 +34,7 @@ pub const MANAGED_EVENT_CAPACITY: usize = 16_384;
 pub struct TargetSelection<'a> {
     pub targets: &'a [TargetArg],
     pub pacing: GroupPacingArg,
+    pub stdin_controlled: bool,
 }
 
 /// Everything a managed run needs, prepared and validated together.
@@ -46,6 +50,8 @@ pub struct ManagedRunSetup {
     pub client: ClientConfig,
     /// Send coordination across active targets.
     pub pacing: ManagedPacing,
+    /// Whether this stream may replace its desired set from stdin.
+    pub stdin_controlled: bool,
 }
 
 impl ManagedRunSetup {
@@ -70,7 +76,7 @@ impl ManagedRunSetup {
     /// Managed driver configuration for this run.
     pub fn managed_config(&self) -> ManagedClientConfig {
         let target_count = self.target_count();
-        ManagedClientConfig {
+        let mut config = ManagedClientConfig {
             client: self.client.clone(),
             pacing: self.pacing,
             completion: ManagedCompletionPolicy::FinishWhenQuiescent,
@@ -78,7 +84,13 @@ impl ManagedRunSetup {
             outcome_history_limit: target_count,
             max_live_target_generations: target_count,
             ..ManagedClientConfig::default()
+        };
+        if self.stdin_controlled {
+            config.completion = ManagedCompletionPolicy::ExplicitStop;
+            config.outcome_history_limit = STDIN_OUTCOME_HISTORY_LIMIT;
+            config.max_live_target_generations = STDIN_MAX_LIVE_TARGET_GENERATIONS;
         }
+        config
     }
 }
 
@@ -91,12 +103,22 @@ pub fn prepare_managed_run(
     duration: Duration,
     selection: TargetSelection<'_>,
 ) -> Result<ManagedRunSetup, String> {
-    let specs = target_specs(selection.targets)?;
+    let specs = if selection.stdin_controlled {
+        if selection.targets.len() > STDIN_MAX_DESIRED_TARGETS {
+            return Err(format!(
+                "initial target set exceeds the {STDIN_MAX_DESIRED_TARGETS}-target limit"
+            ));
+        }
+        super::targets::target_specs_with_empty(selection.targets, true)?
+    } else {
+        target_specs(selection.targets)?
+    };
     let targets = prepare_managed_targets(specs)?;
     Ok(ManagedRunSetup {
         targets,
         client: common.to_client_config(duration),
         pacing: selection.pacing.into(),
+        stdin_controlled: selection.stdin_controlled,
     })
 }
 
@@ -119,17 +141,11 @@ mod tests {
     }
 
     fn unlabeled(addr: &str) -> TargetArg {
-        TargetArg {
+        TargetArg::new(addr)
-            label: None,
-            addr: addr.to_owned(),
-        }
     }
 
     fn labeled(label: &str, addr: &str) -> TargetArg {
-        TargetArg {
+        TargetArg::new(format!("{label}={addr}"))
-            label: Some(label.to_owned()),
-            addr: addr.to_owned(),
-        }
     }
 
     fn prepare(
@@ -137,7 +153,15 @@ mod tests {
         pacing: GroupPacingArg,
         duration: Duration,
     ) -> Result<ManagedRunSetup, String> {
-        prepare_managed_run(&common(&[]), duration, TargetSelection { targets, pacing })
+        prepare_managed_run(
+            &common(&[]),
+            duration,
+            TargetSelection {
+                targets,
+                pacing,
+                stdin_controlled: false,
+            },
+        )
     }
 
     #[test]
@@ -212,6 +236,7 @@ mod tests {
             TargetSelection {
                 targets: &targets,
                 pacing: GroupPacingArg::Staggered,
+                stdin_controlled: false,
             },
         )
         .unwrap();

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

@@ -1,26 +1,99 @@
-use std::collections::HashSet;
+use std::{collections::HashSet, fmt};
 
 use clap::ValueEnum;
-use irtt_client::managed::{ManagedPacing, ManagedTargetConfig, TargetId};
+use irtt_client::{
+    managed::{ManagedPacing, ManagedTargetConfig, TargetId},
+    ClientAuthConfig,
+};
 
-#[derive(Debug, Clone, PartialEq, Eq)]
+/// One raw positional target captured by Clap.
+///
+/// Parsing happens during run preparation so invalid target syntax never makes
+/// Clap include the original argument (which may carry an HMAC key) in an
+/// error diagnostic.
+#[derive(Clone, PartialEq, Eq)]
 pub struct TargetArg {
-    pub label: Option<String>,
+    input: String,
-    pub addr: String,
 }
 
-#[derive(Debug, Clone, PartialEq, Eq)]
+impl TargetArg {
+    pub fn new(input: impl Into<String>) -> Self {
+        Self {
+            input: input.into(),
+        }
+    }
+}
+
+impl fmt::Debug for TargetArg {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str("TargetArg(<redacted>)")
+    }
+}
+
+/// Capture one positional target without exposing it through Clap diagnostics.
+pub fn parse_target(input: &str) -> Result<TargetArg, String> {
+    Ok(TargetArg::new(input))
+}
+
+#[derive(Clone, PartialEq, Eq)]
+pub enum TargetAuth {
+    Inherit,
+    Override(Vec<u8>),
+    Disable,
+}
+
+impl fmt::Debug for TargetAuth {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {
+            Self::Inherit => f.write_str("Inherit"),
+            Self::Override(_) => f.write_str("Override(<redacted>)"),
+            Self::Disable => f.write_str("Disable"),
+        }
+    }
+}
+
+#[derive(Clone, PartialEq, Eq)]
 pub struct TargetSpec {
     pub label: String,
     pub addr: String,
+    pub auth: TargetAuth,
 }
 
-#[derive(Debug, Clone)]
+impl fmt::Debug for TargetSpec {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("TargetSpec")
+            .field("label", &self.label)
+            .field("addr", &self.addr)
+            .field("auth", &self.auth)
+            .finish()
+    }
+}
+
+#[derive(Clone)]
 pub struct PreparedTarget {
     pub label: String,
     pub managed: ManagedTargetConfig,
 }
 
+impl fmt::Debug for PreparedTarget {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("PreparedTarget")
+            .field("label", &self.label)
+            .field("server_addr", &self.managed.server_addr)
+            .field(
+                "auth",
+                &match &self.managed.auth {
+                    None => TargetAuth::Inherit,
+                    Some(ClientAuthConfig { hmac_key: Some(_) }) => {
+                        TargetAuth::Override(Vec::new())
+                    }
+                    Some(ClientAuthConfig { hmac_key: None }) => TargetAuth::Disable,
+                },
+            )
+            .finish()
+    }
+}
+
 #[derive(Debug, Clone, Copy, PartialEq, Eq, ValueEnum)]
 pub enum GroupPacingArg {
     Staggered,
@@ -36,191 +109,383 @@ impl From<GroupPacingArg> for ManagedPacing {
     }
 }
 
-/// Parse one positional target argument, as `TARGET` or `LABEL=TARGET`.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
-pub fn parse_target(input: &str) -> Result<TargetArg, String> {
+enum TargetParseError {
-    match input.split_once('=') {
+    EmptyLabel,
-        None => Ok(TargetArg {
+    EmptyAddress,
-            label: None,
+    InvalidEscape,
-            addr: input.to_owned(),
+    EmptyTarget,
-        }),
+}
-        Some((label, addr)) => {
+
-            if label.is_empty() {
+impl fmt::Display for TargetParseError {
-                return Err("target label must not be empty".to_owned());
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-            }
+        let message = match self {
-            if addr.is_empty() {
+            Self::EmptyLabel => "target label must not be empty",
-                return Err("target address must not be empty".to_owned());
+            Self::EmptyAddress => "target address must not be empty",
-            }
+            Self::InvalidEscape => "invalid target escape sequence",
-            Ok(TargetArg {
+            Self::EmptyTarget => "target must not be empty",
-                label: Some(label.to_owned()),
+        };
-                addr: addr.to_owned(),
+        f.write_str(message)
-            })
-        }
     }
 }
 
-pub fn target_specs(targets: &[TargetArg]) -> Result<Vec<TargetSpec>, String> {
+fn split_unescaped(input: &str, delimiter: char) -> Result<Vec<&str>, TargetParseError> {
+    let mut parts = Vec::new();
+    let mut start = 0;
+    let mut escaped = false;
+    for (index, ch) in input.char_indices() {
+        if escaped {
+            escaped = false;
+        } else if ch == '\\' {
+            escaped = true;
+        } else if ch == delimiter {
+            parts.push(&input[start..index]);
+            start = index + ch.len_utf8();
+        }
+    }
+    if escaped {
+        return Err(TargetParseError::InvalidEscape);
+    }
+    parts.push(&input[start..]);
+    Ok(parts)
+}
+
+fn first_unescaped(input: &str, delimiter: char) -> Result<Option<usize>, TargetParseError> {
+    let mut escaped = false;
+    for (index, ch) in input.char_indices() {
+        if escaped {
+            escaped = false;
+        } else if ch == '\\' {
+            escaped = true;
+        } else if ch == delimiter {
+            return Ok(Some(index));
+        }
+    }
+    if escaped {
+        return Err(TargetParseError::InvalidEscape);
+    }
+    Ok(None)
+}
+
+fn unescape(input: &str) -> Result<String, TargetParseError> {
+    let mut output = String::with_capacity(input.len());
+    let mut escaped = false;
+    for ch in input.chars() {
+        if escaped {
+            if !matches!(ch, '\\' | '=' | ';' | ',' | '@') {
+                return Err(TargetParseError::InvalidEscape);
+            }
+            output.push(ch);
+            escaped = false;
+        } else if ch == '\\' {
+            escaped = true;
+        } else {
+            output.push(ch);
+        }
+    }
+    if escaped {
+        return Err(TargetParseError::InvalidEscape);
+    }
+    Ok(output)
+}
+
+fn hmac_modifier(input: &str) -> Result<Option<usize>, TargetParseError> {
+    let mut escaped = false;
+    for (index, ch) in input.char_indices() {
+        if escaped {
+            escaped = false;
+        } else if ch == '\\' {
+            escaped = true;
+        } else if input[index..].starts_with("@hmac=") {
+            return Ok(Some(index));
+        }
+    }
+    if escaped {
+        return Err(TargetParseError::InvalidEscape);
+    }
+    Ok(None)
+}
+
+fn parse_target_syntax(
+    input: &str,
+) -> Result<(Option<String>, String, TargetAuth), TargetParseError> {
+    if input.is_empty() {
+        return Err(TargetParseError::EmptyTarget);
+    }
+    let (main, auth) = match hmac_modifier(input)? {
+        Some(index) => {
+            let value = unescape(&input[index + "@hmac=".len()..])?;
+            let auth = if value.is_empty() {
+                TargetAuth::Disable
+            } else {
+                TargetAuth::Override(value.into_bytes())
+            };
+            (&input[..index], auth)
+        }
+        None => (input, TargetAuth::Inherit),
+    };
+    let (label, address) = match first_unescaped(main, '=')? {
+        None => (None, unescape(main)?),
+        Some(index) => {
+            let label = unescape(&main[..index])?;
+            let address = unescape(&main[index + '='.len_utf8()..])?;
+            (Some(label), address)
+        }
+    };
+    if label.as_deref().is_some_and(str::is_empty) {
+        return Err(TargetParseError::EmptyLabel);
+    }
+    if address.is_empty() {
+        return Err(TargetParseError::EmptyAddress);
+    }
+    Ok((label, address, auth))
+}
+
+pub(crate) fn target_specs_with_empty(
+    targets: &[TargetArg],
+    allow_empty: bool,
+) -> Result<Vec<TargetSpec>, String> {
     let mut specs = Vec::with_capacity(targets.len());
-    let mut unlabeled_counts = std::collections::HashMap::<&str, usize>::new();
+    let mut unlabeled_counts = std::collections::HashMap::<String, usize>::new();
-    for target in targets {
+    for (index, target) in targets.iter().enumerate() {
-        let label = match &target.label {
+        let (explicit_label, addr, auth) = parse_target_syntax(&target.input)
-            Some(label) => label.clone(),
+            .map_err(|error| format!("invalid target {}: {error}", index + 1))?;
+        let label = match explicit_label {
+            Some(label) => label,
             None => {
-                let count = unlabeled_counts.entry(target.addr.as_str()).or_default();
+                let count = unlabeled_counts.entry(addr.clone()).or_default();
                 *count += 1;
                 if *count == 1 {
-                    target.addr.clone()
+                    addr.clone()
                 } else {
-                    format!("{}#{}", target.addr, *count)
+                    format!("{}#{}", addr, *count)
                 }
             }
         };
-        specs.push(TargetSpec {
+        specs.push(TargetSpec { label, addr, auth });
-            label,
-            addr: target.addr.clone(),
-        });
     }
 
-    if specs.is_empty() {
+    if specs.is_empty() && !allow_empty {
         return Err("at least one target is required unless --list-columns is set".to_owned());
     }
 
     let mut labels = HashSet::new();
     for spec in &specs {
         if !labels.insert(spec.label.clone()) {
-            return Err(format!("duplicate target label {:?}", spec.label));
+            return Err("duplicate target label".to_owned());
         }
     }
 
     Ok(specs)
 }
 
+pub fn target_specs(targets: &[TargetArg]) -> Result<Vec<TargetSpec>, String> {
+    target_specs_with_empty(targets, false)
+}
+
 pub fn prepare_managed_targets(specs: Vec<TargetSpec>) -> Result<Vec<PreparedTarget>, String> {
     let mut targets = Vec::with_capacity(specs.len());
     for spec in specs {
+        let mut managed = ManagedTargetConfig::new(TargetId::from(spec.label.clone()), spec.addr);
+        managed.auth = match spec.auth {
+            TargetAuth::Inherit => None,
+            TargetAuth::Override(hmac_key) => Some(ClientAuthConfig {
+                hmac_key: Some(hmac_key),
+            }),
+            TargetAuth::Disable => Some(ClientAuthConfig { hmac_key: None }),
+        };
         targets.push(PreparedTarget {
-            label: spec.label.clone(),
+            label: spec.label,
-            managed: ManagedTargetConfig::new(TargetId::from(spec.label), spec.addr),
+            managed,
         });
     }
     Ok(targets)
 }
 
+/// Parse one complete stdin target set after its line terminator was removed.
+///
+/// Commas frame stdin elements only; positional target arguments do not use
+/// this framing and may therefore contain raw commas.
+pub fn parse_stdin_target_set(
+    record: &str,
+    maximum_targets: usize,
+) -> Result<Vec<PreparedTarget>, String> {
+    if record == "[]" {
+        return Ok(Vec::new());
+    }
+    let elements = split_unescaped(record, ',').map_err(|error| error.to_string())?;
+    if elements.len() > maximum_targets {
+        return Err(format!(
+            "target set exceeds the {maximum_targets}-target limit"
+        ));
+    }
+    let args = elements.into_iter().map(TargetArg::new).collect::<Vec<_>>();
+    prepare_managed_targets(target_specs_with_empty(&args, true)?)
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
 
-    fn unlabeled(addr: &str) -> TargetArg {
+    fn target(input: &str) -> TargetArg {
-        TargetArg {
+        TargetArg::new(input)
-            label: None,
-            addr: addr.to_owned(),
-        }
     }
 
-    fn labeled(label: &str, addr: &str) -> TargetArg {
+    fn specs(inputs: &[&str]) -> Result<Vec<TargetSpec>, String> {
-        TargetArg {
+        target_specs(&inputs.iter().map(|input| target(input)).collect::<Vec<_>>())
-            label: Some(label.to_owned()),
-            addr: addr.to_owned(),
-        }
     }
 
     #[test]
-    fn parse_target_without_equals_is_unlabeled() {
+    fn legacy_target_syntax_and_ipv6_remain_supported() {
-        let target = parse_target("host.example").unwrap();
+        let parsed = specs(&[
-        assert_eq!(target.label, None);
+            "host.example",
-        assert_eq!(target.addr, "host.example");
+            "host.example:2112",
-
+            "[::1]:2112",
-        let target = parse_target("host.example:2112").unwrap();
+            "eu=host.example",
-        assert_eq!(target.label, None);
+        ])
-        assert_eq!(target.addr, "host.example:2112");
+        .unwrap();
-
+        assert_eq!(parsed[0].label, "host.example");
-        let target = parse_target("[::1]:2112").unwrap();
+        assert_eq!(parsed[1].label, "host.example:2112");
-        assert_eq!(target.label, None);
+        assert_eq!(parsed[2].label, "[::1]:2112");
-        assert_eq!(target.addr, "[::1]:2112");
+        assert_eq!(parsed[3].label, "eu");
+        assert!(parsed
+            .iter()
+            .all(|target| matches!(target.auth, TargetAuth::Inherit)));
     }
 
     #[test]
-    fn parse_target_with_equals_splits_on_first() {
+    fn target_hmac_supports_inherit_override_disable_and_base64_padding() {
-        let target = parse_target("eu=host.example").unwrap();
+        let parsed = specs(&[
-        assert_eq!(target.label, Some("eu".to_owned()));
+            "default=default.example",
-        assert_eq!(target.addr, "host.example");
+            "private=private.example@hmac=YWJjZA==",
-
+            "public=public.example@hmac=",
-        let target = parse_target("eu=host.example:2112").unwrap();
+        ])
-        assert_eq!(target.label, Some("eu".to_owned()));
+        .unwrap();
-        assert_eq!(target.addr, "host.example:2112");
+        assert!(matches!(parsed[0].auth, TargetAuth::Inherit));
+        assert_eq!(parsed[1].auth, TargetAuth::Override(b"YWJjZA==".to_vec()));
+        assert!(matches!(parsed[2].auth, TargetAuth::Disable));
     }
 
     #[test]
-    fn parse_target_rejects_empty_label_or_address() {
+    fn target_delimiters_are_escaped_contextually() {
-        assert!(parse_target("=host.example").is_err());
+        let parsed = specs(&["eu\\=west=host\\@hmac=literal@hmac=a\\@b\\,c\\=d\\\\e"]).unwrap();
-        assert!(parse_target("eu=").is_err());
+        assert_eq!(parsed[0].label, "eu=west");
+        assert_eq!(parsed[0].addr, "host@hmac=literal");
+        assert_eq!(parsed[0].auth, TargetAuth::Override(b"a@b,c=d\\e".to_vec()));
+    }
+
+    #[test]
+    fn positional_commas_are_not_reserved() {
+        let parsed = specs(&["edge=host,region@hmac=key,part"]).unwrap();
+        assert_eq!(parsed[0].addr, "host,region");
+        assert_eq!(parsed[0].auth, TargetAuth::Override(b"key,part".to_vec()));
+    }
+
+    #[test]
+    fn parser_diagnostics_and_debug_do_not_reveal_hmac_values() {
+        let secret = "very-secret-value";
+        let error = specs(&[&format!("target=host@hmac={secret}\\q")]).unwrap_err();
+        assert!(!error.contains(secret));
+        assert!(!format!("{:?}", target(&format!("target=host@hmac={secret}"))).contains(secret));
+        assert!(
+            !format!("{:?}", TargetAuth::Override(secret.as_bytes().to_vec())).contains(secret)
+        );
     }
 
     #[test]
     fn target_specs_suffix_repeated_unlabeled_and_reject_duplicate_labels() {
-        let targets = vec![unlabeled("host-a:2112"), unlabeled("host-a:2112")];
+        let parsed = specs(&["host-a:2112", "host-a:2112"]).unwrap();
-        let specs = target_specs(&targets).unwrap();
+        assert_eq!(parsed[0].label, "host-a:2112");
-
+        assert_eq!(parsed[1].label, "host-a:2112#2");
-        assert_eq!(specs[0].label, "host-a:2112");
+        assert_eq!(
-        assert_eq!(specs[1].label, "host-a:2112#2");
+            specs(&["host-a:2112", "host-a:2112=host-b:2112"]).unwrap_err(),
-
+            "duplicate target label"
-        let targets = vec![
+        );
-            unlabeled("host-a:2112"),
-            labeled("host-a:2112", "host-b:2112"),
-        ];
-        let err = target_specs(&targets).unwrap_err();
-        assert!(err.contains("duplicate target label"));
     }
 
     #[test]
-    fn target_specs_preserve_argument_order_with_mixed_labels() {
+    fn target_specs_preserve_argument_order_and_unlabeled_counts() {
-        let targets = vec![
+        let parsed = specs(&["local", "eu=eu.example", "foo", "us=us.example", "foo"]).unwrap();
-            unlabeled("local"),
+        let labels: Vec<_> = parsed.iter().map(|target| target.label.as_str()).collect();
-            labeled("eu", "eu.example"),
+        assert_eq!(labels, ["local", "eu", "foo", "us", "foo#2"]);
-            unlabeled("backup"),
+        let addresses: Vec<_> = parsed.iter().map(|target| target.addr.as_str()).collect();
-            labeled("us", "us.example"),
+        assert_eq!(
-        ];
+            addresses,
-        let specs = target_specs(&targets).unwrap();
+            ["local", "eu.example", "foo", "us.example", "foo"]
-
+        );
-        let labels: Vec<_> = specs.iter().map(|spec| spec.label.as_str()).collect();
-        assert_eq!(labels, ["local", "eu", "backup", "us"]);
-        let addrs: Vec<_> = specs.iter().map(|spec| spec.addr.as_str()).collect();
-        assert_eq!(addrs, ["local", "eu.example", "backup", "us.example"]);
-    }
-
-    #[test]
-    fn target_specs_count_unlabeled_occurrences_independently_of_explicit_labels() {
-        let targets = vec![unlabeled("foo"), labeled("eu", "foo"), unlabeled("foo")];
-        let specs = target_specs(&targets).unwrap();
-
-        let labels: Vec<_> = specs.iter().map(|spec| spec.label.as_str()).collect();
-        assert_eq!(labels, ["foo", "eu", "foo#2"]);
     }
 
     #[test]
     fn target_specs_reject_generated_suffix_collisions() {
-        let targets = vec![
+        assert_eq!(
-            unlabeled("host.example"),
+            specs(&[
-            unlabeled("host.example"),
+                "host.example",
-            labeled("host.example#2", "other.example"),
+                "host.example",
-        ];
+                "host.example#2=other.example"
-        let err = target_specs(&targets).unwrap_err();
+            ])
-        assert!(err.contains("duplicate target label"));
+            .unwrap_err(),
+            "duplicate target label"
+        );
     }
 
     #[test]
-    fn target_preparation_preserves_hostname_and_allows_duplicate_endpoints() {
+    fn malformed_target_syntax_is_rejected_without_echoing_input() {
-        let specs = vec![
+        for input in ["=host", "label=", "host@hmac=value\\q", "host\\x"] {
-            TargetSpec {
+            assert!(specs(&[input]).is_err(), "{input}");
-                label: "a".to_owned(),
+        }
-                addr: "example.test".to_owned(),
+    }
-            },
+
-            TargetSpec {
+    #[test]
-                label: "b".to_owned(),
+    fn target_preparation_maps_auth_to_managed_config() {
-                addr: "example.test".to_owned(),
+        let prepared =
-            },
+            prepare_managed_targets(specs(&["a=one@hmac=key", "b=two@hmac="]).unwrap()).unwrap();
-        ];
+        assert_eq!(
-        let targets = prepare_managed_targets(specs).unwrap();
+            prepared[0]
-        assert_eq!(targets[0].managed.server_addr, "example.test");
+                .managed
-        assert_eq!(targets[1].managed.server_addr, "example.test");
+                .auth
+                .as_ref()
+                .unwrap()
+                .hmac_key
+                .as_deref(),
+            Some(b"key".as_slice())
+        );
+        assert_eq!(prepared[1].managed.auth.as_ref().unwrap().hmac_key, None);
+    }
+
+    #[test]
+    fn target_preparation_preserves_duplicate_endpoints() {
+        let prepared =
+            prepare_managed_targets(specs(&["a=example.test", "b=example.test"]).unwrap()).unwrap();
+        assert_eq!(prepared[0].managed.server_addr, "example.test");
+        assert_eq!(prepared[1].managed.server_addr, "example.test");
+    }
+
+    #[test]
+    fn stdin_target_sets_frame_commas_without_trimming_payload() {
+        let parsed = parse_stdin_target_set("a=one@hmac=x\\,y,b=two", 128).unwrap();
+        assert_eq!(
+            parsed[0].managed.auth.as_ref().unwrap().hmac_key.as_deref(),
+            Some(b"x,y".as_slice())
+        );
+        assert_eq!(parsed[1].label, "b");
+        assert_eq!(
+            parse_stdin_target_set(" []", 128).unwrap()[0]
+                .managed
+                .server_addr,
+            " []"
+        );
+        assert_eq!(
+            parse_stdin_target_set("[] ", 128).unwrap()[0]
+                .managed
+                .server_addr,
+            "[] "
+        );
+        assert!(parse_stdin_target_set("", 128).is_err());
+        assert!(parse_stdin_target_set("a=one,b=two", 1).is_err());
+    }
+
+    #[test]
+    fn stdin_empty_set_is_exactly_bracket_pair() {
+        assert!(parse_stdin_target_set("[]", 128).unwrap().is_empty());
     }
 }

crates/irtt-client/AGENTS.md

@@ -26,30 +26,30 @@ configuration (`try_enable_tx_timestamping` restores it explicitly) and
 timing falls back to userspace `sent_at` as it always has. TX capability
 failure is never a public error and is never logged from the library.
 
-### Correlation invariant: kernel ID == wire sequence
+### Best-effort kernel-ID correlation
 
-The client uses the kernel's automatic `OPT_ID` directly as the probe's wire
+The client uses the kernel's automatic `OPT_ID` as the probe's wire-sequence
-sequence number — no separate correlation map. This is safe because:
+correlation ID — no separate correlation map. On the normal successful-send
+path, both counters start at zero after Open and advance together. This is
+not a permanent identity: a kernel ID can theoretically be consumed while a
+send is being prepared and then survive a subsequent send failure, leaving
+kernel IDs one or more steps ahead of `next_wire_seq`. Do not restore an
+assumption that failed or nonblocking sends cannot cause that desynchrony.
 
-- **A failed/nonblocking send never consumes an ID.** Linux increments the
+The effect is confined to the optional timing enhancement. A kernel timestamp
-  per-socket ID counter (`sk->sk_tskey`) speculatively while building a
+whose ID cannot be matched to a pending or retained timed-out probe is
-  datagram and rolls the increment back (`atomic_dec`) on every error path
+discarded, as is any implausible timestamp; `sent_at` remains the ordinary
-  out of `__ip_append_data`/`__ip6_append_data`
+userspace fallback. **After every failed probe submission, disable kernel-ID
-  (`net/ipv4/ip_output.c`, `net/ipv6/ip6_output.c`), guarded by a local
+correlation for the rest of that session.** A gap means an otherwise plausible
-  `hold_tskey` flag. A `WouldBlock` `try_send` therefore can never leave a
+later ID can name the wrong probe, so subsequent error-queue timestamps must
-  gap in, or otherwise advance, the ID the kernel will assign to the next
+be discarded rather than attached by ID. This is safe because:
-  *successful* submission. (`include/net/sock.h`'s `_sock_tx_timestamp`
+
-  performs the same increment for the non-corked path.) Client-side, the
+- **Normal successful sends track together.** `wire_seq` starts at 0 on every
-  existing send transaction only calls `commit_probe_sent` — which is the
+  successful Open (`SessionMachine::commit_open` builds a fresh
-  only thing that advances `next_wire_seq` — after a successful socket send;
+  `ActiveSession` with `next_wire_seq: 0`) and advances by exactly 1 only via
-  a `WouldBlock` result never reaches it.
+  `commit_probe_sent`, after a confirmed successful socket send. TX
-- **The two counters start together and advance together.** `wire_seq`
+  timestamping is enabled after that same successful Open and before any probe
-  starts at 0 on every successful Open (`SessionMachine::commit_open` builds
+  is sent, so the normal zero points line up.
-  a fresh `ActiveSession` with `next_wire_seq: 0`) and advances by exactly 1
-  only via `commit_probe_sent`, which only runs after a confirmed successful
-  send — the same condition under which the kernel's counter advances by 1.
-  TX timestamping is enabled only after that same successful Open and before
-  any probe is sent, so both counters' zero points line up exactly.
 - **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

crates/irtt-client/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "irtt-client"
-version = "0.5.0"
+version = "0.5.1"
 description = "IRTT-compatible Rust client library"
 edition.workspace = true
 license.workspace = true
@@ -44,6 +44,8 @@ required-features = ["tokio"]
 doc-scrape-examples = true
 
 [dev-dependencies]
-irtt-server.workspace = true
+# Keep the packaged client testable against the latest published server while
+# workspace tests continue to exercise the local source through this path.
+irtt-server = { version = "0.5.1", path = "../irtt-server" }
 proptest = "1.11.0"
 tokio = { version = "1.53.1", default-features = false, features = ["rt", "sync"] }

crates/irtt-client/src/async_client.rs

@@ -608,8 +608,14 @@ impl AsyncClient {
                 // No sent_at measurement, no machine commit, no schedule
                 // commit: the transaction is fully discarded and retried
                 // with a fresh send_anchor on the next loop iteration.
-                Err(error) if error.kind() == io::ErrorKind::WouldBlock => continue,
+                Err(error) if error.kind() == io::ErrorKind::WouldBlock => {
-                Err(error) => return Poll::Ready(Err(ClientError::Socket(error))),
+                    self.machine.invalidate_kernel_tx_correlation();
+                    continue;
+                }
+                Err(error) => {
+                    self.machine.invalidate_kernel_tx_correlation();
+                    return Poll::Ready(Err(ClientError::Socket(error)));
+                }
             };
 
             #[cfg(not(test))]

crates/irtt-client/src/client.rs

@@ -163,12 +163,13 @@ impl Client {
     ///
     /// On success, returns the negotiated open outcome and transitions the
     /// client into either an open probe session or completed no-test state.
-    /// Open attempts use [`ClientConfig::open_timeouts`]. Malformed, unrelated,
+    /// Open attempts use [`ClientConfig::open_timeouts`]. Malformed or
-    /// or unauthenticated datagrams are ignored until the current attempt's
+    /// unrelated datagrams are ignored until the current attempt's absolute
-    /// absolute deadline, so one attempt may consume several datagrams without
+    /// deadline, so one attempt may consume several datagrams without
     /// retransmitting. Silence or ignored traffic eventually produces
-    /// [`ClientError::OpenTimeout`], while authenticated incompatibility remains
+    /// [`ClientError::OpenTimeout`]. A structurally recognizable malformed or
-    /// terminal.
+    /// 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
@@ -523,11 +524,18 @@ impl Client {
             .unwrap_or_else(Instant::now);
         #[cfg(test)]
         if fail_send {
+            runtime.invalidate_kernel_tx_correlation();
             return Err(ClientError::Socket(io::Error::other(
                 "injected probe send failure",
             )));
         }
-        let bytes = socket.send(&prepared.bytes)?;
+        let bytes = match socket.send(&prepared.bytes) {
+            Ok(bytes) => bytes,
+            Err(error) => {
+                runtime.invalidate_kernel_tx_correlation();
+                return Err(ClientError::Socket(error));
+            }
+        };
         #[cfg(not(test))]
         let send_finished_at = Instant::now();
         #[cfg(test)]

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

@@ -250,15 +250,11 @@ fn dynamic_update_reaches_background_worker() {
         .unwrap();
     let handle = owner.handle();
 
-    let acknowledgement = test_runtime().block_on(async {
+    let acknowledgement = handle
-        timeout(
+        .update_targets(vec![target(&server)])
-            Duration::from_secs(2),
-            handle.update_targets(vec![target(&server)]).unwrap(),
-        )
-        .await
         .unwrap()
-        .unwrap()
+        .blocking_wait()
-    });
+        .unwrap();
     assert_eq!(acknowledgement.sequence, 1);
     server.wait_probe();
     test_runtime().block_on(async {

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

@@ -301,6 +301,19 @@ pub struct ManagedCommandReceipt {
     receiver: oneshot::Receiver<Result<ManagedCommandAcknowledgement, ManagedCommandApplyError>>,
 }
 
+impl ManagedCommandReceipt {
+    /// Block until the target-set transaction is applied or rejected.
+    ///
+    /// This is for synchronous callers such as [`crate::managed::BlockingManagedClient`]. It
+    /// must not be called from an asynchronous runtime; use the [`Future`]
+    /// implementation there instead.
+    pub fn blocking_wait(self) -> Result<ManagedCommandAcknowledgement, ManagedCommandApplyError> {
+        self.receiver
+            .blocking_recv()
+            .unwrap_or(Err(ManagedCommandApplyError::AcknowledgementDisconnected))
+    }
+}
+
 impl Future for ManagedCommandReceipt {
     type Output = Result<ManagedCommandAcknowledgement, ManagedCommandApplyError>;
     fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
@@ -1600,6 +1613,30 @@ impl ManagedClientTask {
         self.send_gate = self.send_gate.filter(|gate| *gate > now);
     }
 
+    /// The next stagger gate after a send was accepted at `accepted_at`.
+    ///
+    /// The gate advances on its **own** cadence rather than being re-anchored
+    /// on every observed accept time. Anchoring on `accepted_at` folds each
+    /// send's wakeup latency into the next slot and then into every slot after
+    /// it, so the gate — and with it the whole group's send cadence — drifts
+    /// later without bound while the per-target schedules stay on their
+    /// absolute grid. The drift is not hypothetical: it shows up as a
+    /// monotonically growing `EchoSent::timer_error` and, once it exceeds one
+    /// interval, as probe slots the schedule then skips.
+    ///
+    /// `accepted_at` is still the anchor in the two cases where continuing the
+    /// old cadence would be wrong: there is no previous gate, or the pacer has
+    /// fallen a full slot behind it. Re-anchoring there is what keeps a gate
+    /// stranded in the past from releasing a burst of catch-up sends once the
+    /// group starts moving again.
+    fn next_stagger_gate(&self, spacing: Duration, accepted_at: Instant) -> Option<Instant> {
+        let base = match self.send_gate {
+            Some(gate) if gate <= accepted_at && accepted_at.duration_since(gate) < spacing => gate,
+            _ => accepted_at,
+        };
+        base.checked_add(spacing)
+    }
+
     fn record_stagger_acceptance(
         &mut self,
         result: SendResult,
@@ -1613,7 +1650,7 @@ impl ManagedClientTask {
             return;
         };
         self.last_stagger_send = Some(accepted_at);
-        self.send_gate = accepted_at.checked_add(spacing);
+        self.send_gate = self.next_stagger_gate(spacing, accepted_at);
         #[cfg(test)]
         if let Some(observations) = &self.stagger_observations {
             observations.lock().unwrap().push((_active, spacing));

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

@@ -1576,6 +1576,37 @@ fn authenticated_peer_close_outcome() {
     assert!(!has_close(&records));
 }
 
+#[test]
+fn peer_close_leaves_other_explicitly_managed_targets_running() {
+    let closing = start_server(ServerBehavior::PeerClose, None);
+    let continuing = start_server(ServerBehavior::Echo, None);
+    let mut managed = config(ManagedPacing::Staggered);
+    managed.completion = ManagedCompletionPolicy::ExplicitStop;
+    managed.client.duration = None;
+    let (task, handle) = ManagedClient::task(
+        managed,
+        vec![
+            target("closing", closing.addr),
+            target("continuing", continuing.addr),
+        ],
+    )
+    .unwrap();
+    let runtime = runtime();
+    let mut task = Box::pin(task);
+
+    drive_task_until(&runtime, &mut task, |task| {
+        handle.status().peer_closed_target_outcomes == 1
+            && task.targets[1].counters.packets_sent != 0
+    });
+    assert_eq!(handle.status().lifecycle, ManagedLifecycle::Running);
+
+    let stop = handle.stop();
+    runtime.block_on(task);
+    runtime.block_on(stop);
+    closing.finish();
+    assert!(!probes(&continuing.finish()).is_empty());
+}
+
 #[test]
 fn peer_close_during_stop_drain_remains_authoritative() {
     let key = b"managed-drain-peer-close".to_vec();
@@ -1864,6 +1895,78 @@ fn stagger_gate_tracks_active_membership() {
     second.finish();
 }
 
+/// The stagger gate must not fold each send's observed wakeup latency into
+/// every later slot.
+///
+/// The gate is the binding constraint on when the *group* may send next (see
+/// `next_deadline`), while each target's own schedule stays on an absolute
+/// grid anchored at its open. Re-anchoring the gate on every observed accept
+/// time therefore made the whole group's cadence drift later without bound:
+/// `EchoSent::timer_error` grew monotonically, and once the drift exceeded one
+/// interval `skip_missed_probe_slots_at` started dropping probe slots
+/// outright. Measured before this was fixed, a single-target 20 s run at a
+/// 50 ms interval sent 381 probes instead of 400.
+///
+/// This asserts the invariant directly rather than through a real-time run,
+/// because reproducing accumulation behaviorally needs seconds of wall clock
+/// and a jitter assumption. Two properties, both durable:
+///
+/// - while the pacer keeps up, N accepted sends advance the gate by exactly
+///   N spacings from the first anchor, whatever lateness each send is
+///   observed with;
+/// - a gate the pacer has fallen a full spacing behind re-anchors on the
+///   accept time instead, so a stranded gate cannot release a burst of
+///   catch-up sends.
+#[test]
+fn the_stagger_gate_advances_by_one_spacing_per_send_without_accumulating_lateness() {
+    // No socket is involved: the gate is driven directly and the task is never
+    // polled, so an unreachable address is all a valid target set needs here.
+    let (mut task, _) = ManagedClient::task(
+        config(ManagedPacing::Staggered),
+        vec![target("only", "127.0.0.1:9".parse().unwrap())],
+    )
+    .unwrap();
+
+    let spacing = Duration::from_millis(50);
+    let start = Instant::now();
+    let lateness = Duration::from_millis(3);
+
+    task.record_stagger_acceptance(
+        SendResult::Ready { accepted: true },
+        Some((1, spacing)),
+        start,
+    );
+    assert_eq!(task.send_gate, Some(start + spacing), "first send anchors");
+
+    // Every later send is observed `lateness` after the gate that released it.
+    // The gate must still advance one spacing per send from `start`, not
+    // `spacing + lateness`.
+    for slot in 1..=8_u32 {
+        let released_at = start + spacing * slot;
+        task.record_stagger_acceptance(
+            SendResult::Ready { accepted: true },
+            Some((1, spacing)),
+            released_at + lateness,
+        );
+        assert_eq!(
+            task.send_gate,
+            Some(start + spacing * (slot + 1)),
+            "slot {slot} accumulated observed lateness into the gate"
+        );
+    }
+
+    // A full spacing behind is no longer the same cadence, so the gate
+    // re-anchors rather than staying stranded in the past.
+    let stalled_gate = task.send_gate.expect("the gate is set");
+    let resumed_at = stalled_gate + spacing;
+    task.record_stagger_acceptance(
+        SendResult::Ready { accepted: true },
+        Some((1, spacing)),
+        resumed_at,
+    );
+    assert_eq!(task.send_gate, Some(resumed_at + spacing));
+}
+
 #[test]
 fn timeout_discovery_inspects_at_most_one_budget_of_targets() {
     let target_count = TIMEOUT_WORK_BUDGET + 1;

crates/irtt-client/src/probe.rs

@@ -39,7 +39,8 @@ pub(crate) struct PendingProbe {
     /// eligible only for upstream one-way delay after local plausibility
     /// validation against `tx_not_before_wall` (see `compute_one_way`'s
     /// `preferred_send_wall`). `sent_at` remains the userspace fallback for
-    /// upstream one-way delay when this is absent or implausible.
+    /// upstream one-way delay when this is absent, implausible, or kernel-ID
+    /// correlation was invalidated by a failed probe submission.
     pub kernel_tx_timestamp: Option<SystemTime>,
 }
 

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

@@ -12,14 +12,17 @@
 //! After a successful Open, the client adapter best-effort upgrades the
 //! socket from [`RX_TIMESTAMPING_FLAGS`] to [`error_queue::TX_TIMESTAMPING_FLAGS`]
 //! via [`try_enable_tx_timestamping`]. When that succeeds, the automatic
-//! `SOF_TIMESTAMPING_OPT_ID` counter the kernel assigns to each successfully
+//! `SOF_TIMESTAMPING_OPT_ID` counter normally tracks the probe wire sequence
-//! submitted datagram is used directly as the probe's wire sequence number
+//! after successful sends, so it is used as a best-effort correlation ID.
-//! (see the client crate's `AGENTS.md` for the correlation invariant this
+//! A kernel ID can theoretically be consumed by a send that later fails,
-//! relies on). [`drain_tx_timestamps`] performs a small bounded, nonblocking
+//! desynchronizing that correlation. [`drain_tx_timestamps`] discards
-//! read of `MSG_ERRQUEUE` so the adapter can opportunistically collect those
+//! unmatched or implausible records; the userspace `sent_at` timestamp remains
-//! timestamps without ever waiting for one. The observed kernel TX wall time
+//! the fallback. After a probe send failure, correlation is disabled for that
-//! is retained as metadata only; it is not consumed by any measurement in
+//! session so later IDs cannot be misattributed. It performs a small bounded,
-//! this change.
+//! nonblocking read of
+//! `MSG_ERRQUEUE` so the adapter can opportunistically collect timestamps
+//! without ever waiting for one. The observed kernel TX wall time is retained
+//! as metadata only; it is not consumed by any measurement in this change.
 
 use std::{
     io::{self, IoSliceMut},

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

@@ -624,22 +624,14 @@ mod tests {
         ));
     }
 
-    // NOTE: a live test proving that a failed nonblocking `sendmsg` does not
+    // NOTE: There is no live test for whether a failed nonblocking `sendmsg`
-    // consume an automatic OPT_ID is not included here. Forcing a reliable,
+    // consumes an automatic OPT_ID. Forcing a reliable, non-flaky `WouldBlock`
-    // non-flaky `WouldBlock` on a connected loopback UDP socket (e.g. via
+    // on a connected loopback UDP socket (for example through socket-buffer
-    // socket-buffer saturation) has no deterministic OS-level mechanism
+    // saturation) has no deterministic OS-level mechanism in this environment,
-    // available in this environment, and the repository's testing policy
+    // and the repository's testing policy forbids sleep/saturation-based
-    // explicitly forbids faking coverage with sleep/saturation-based
+    // flakiness. The correlation is intentionally best effort: a kernel ID can
-    // flakiness. That safety is instead established from Linux kernel
+    // theoretically be consumed by a send that later fails. The deterministic
-    // source: `_sock_tx_timestamp` (include/net/sock.h) and
+    // adapter test covers only the local half: an injected `WouldBlock` does
-    // `__ip_append_data`/`__ip6_append_data` (net/ipv4/ip_output.c,
+    // not advance the local wire-sequence counter. Any later unmatched kernel
-    // net/ipv6/ip6_output.c) increment `sk->sk_tskey` speculatively before
+    // timestamp is discarded and the userspace `sent_at` remains the fallback.
-    // a datagram is fully built and explicitly `atomic_dec` it back out on
-    // every error path (tracked via a local `hold_tskey` flag), so a failed
-    // send can never leave a gap in — or otherwise advance — the ID space
-    // the kernel hands out to successfully submitted datagrams. See the
-    // client crate's `AGENTS.md` for the full citation. The client-side
-    // half of this invariant (a `WouldBlock` `try_send` never advances the
-    // local wire-sequence counter used as the correlation ID) is covered by
-    // a deterministic test in the adapter module that injects `WouldBlock`.
 }

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

@@ -60,6 +60,7 @@ struct ActiveSession {
     pending: PendingMap,
     timed_out: TimedOutMap,
     completed: CompletedSet,
+    kernel_tx_correlation_valid: bool,
 }
 
 #[derive(Debug)]
@@ -423,15 +424,27 @@ impl SessionMachine {
         }
     }
 
+    /// Disable Linux kernel TX timestamp correlation after a probe send fails.
+    ///
+    /// A failed submission can consume a kernel `SOF_TIMESTAMPING_OPT_ID`
+    /// without advancing the wire sequence. Existing associated timestamps
+    /// remain valid observations; later error-queue timestamps cannot be
+    /// associated safely and are ignored for the rest of this session.
+    pub(crate) fn invalidate_kernel_tx_correlation(&mut self) {
+        if let MachineState::Open(session) = &mut self.state {
+            session.kernel_tx_correlation_valid = false;
+        }
+    }
+
     /// Record an observed Linux kernel TX timestamp for `wire_seq`, the
     /// automatic `SOF_TIMESTAMPING_OPT_ID` the kernel assigned when the
     /// datagram was submitted.
     ///
-    /// `wire_seq` doubles as that correlation ID: both counters start at
+    /// `wire_seq` normally matches that correlation ID after successful
-    /// zero for a session's first timestamped send and advance by exactly
+    /// sends. This is best effort rather than an invariant: a kernel ID can
-    /// one only on a confirmed successful submission, so they stay
+    /// theoretically be consumed by a send that later fails, leaving the
-    /// identical for the life of one open session (see the client crate's
+    /// counters desynchronized. An unmatched or implausible ID is discarded;
-    /// `AGENTS.md` for the full invariant).
+    /// the probe's userspace `sent_at` remains the fallback.
     ///
     /// Updates a still-pending or already-timed-out probe in place. Never
     /// resurrects a completed, evicted, or unknown probe, and never touches
@@ -443,6 +456,9 @@ impl SessionMachine {
         let MachineState::Open(session) = &mut self.state else {
             return;
         };
+        if !session.kernel_tx_correlation_valid {
+            return;
+        }
         if let Some(probe) = session.pending.get_mut(wire_seq) {
             probe.kernel_tx_timestamp.get_or_insert(timestamp);
             return;
@@ -636,6 +652,7 @@ impl SessionMachine {
             pending: PendingMap::new(self.config.max_pending_probes),
             timed_out: TimedOutMap::new(self.config.max_pending_probes),
             completed: CompletedSet::new(self.config.max_pending_probes),
+            kernel_tx_correlation_valid: true,
         }));
 
         let event = ClientEvent::SessionStarted {
@@ -1231,6 +1248,7 @@ mod tests {
             pending: PendingMap::new(max_pending_probes),
             timed_out: TimedOutMap::new(max_pending_probes),
             completed: CompletedSet::new(max_pending_probes),
+            kernel_tx_correlation_valid: true,
         }));
         machine
     }
@@ -2873,6 +2891,25 @@ mod tests {
         );
     }
 
+    #[test]
+    fn invalidated_kernel_tx_correlation_uses_userspace_send_time() {
+        let mono = Instant::now();
+        let mut machine = upstream_probe(send_wall_ms(1_000), mono);
+
+        // A failed send can consume a kernel ID without advancing wire_seq.
+        // A later timestamp whose ID happens to match a pending wire sequence
+        // must not be associated after that gap.
+        machine.invalidate_kernel_tx_correlation();
+        machine.record_kernel_tx_timestamp(0, send_wall_ms(1_005));
+
+        let events = upstream_reply(&mut machine, 1_020, send_wall_ms(1_040), mono);
+
+        assert_eq!(
+            reply_one_way(&events).unwrap().client_to_server,
+            Some(SignedDuration::from_nanos(20_000_000))
+        );
+    }
+
     #[test]
     fn upstream_one_way_delay_falls_back_without_kernel_tx() {
         let mono = Instant::now();
@@ -3195,6 +3232,7 @@ mod tests {
                 pending: PendingMap::new(MAX_PENDING_PROBES),
                 timed_out: TimedOutMap::new(MAX_PENDING_PROBES),
                 completed: CompletedSet::new(MAX_PENDING_PROBES),
+                kernel_tx_correlation_valid: true,
             }));
             (machine, params)
         }

crates/irtt-server/AGENTS.md

@@ -500,13 +500,14 @@ session policy lives.
   unmarked reply into a *dropped* one, because an unappliable marking stops the
   send. Verify a platform before extending that list.
 - A genuinely dual-stack `[::]` listener still emits **unmarked** IPv4-mapped
-  replies, and this is known. It is not fixed by choosing the option per reply,
+  replies on Linux. When reply DSCP/traffic-class marking for IPv4 peers
-  for the macOS reason above, and it predates wildcard source selection. Leave it
+  matters, configure the normal same-port `[::]:PORT` plus `0.0.0.0:PORT`
-  until it is worth its own slice, and do not "fix" it by weakening the rule that
+  listener pair instead; `ServerSet` makes the IPv6 half IPv6-only for that
-  an unappliable marking stops the send. The crate forbids unsafe code;
+  pair. Do not force `IPV6_V6ONLY` on every lone IPv6 listener, and do not
-  there is no raw `setsockopt` and no `sendmsg`/`cmsg` machinery. Keep the
+  weaken the rule that an unappliable marking stops the send. The crate forbids
-  target lists identical to the pinned `socket2` version's own gates — check
+  unsafe code; there is no raw `setsockopt` and no `sendmsg`/`cmsg` machinery.
-  its source rather than copying another crate's older matrix.
+  Keep the target lists identical to the pinned `socket2` version's own gates
+  — check its source rather than copying another crate's older matrix.
 
 ## Rate, lifetime and server-initiated close
 

crates/irtt-server/src/set.rs

@@ -91,6 +91,14 @@ impl ServerSet {
     /// An IPv4-mapped address such as `[::ffff:0.0.0.0]` is an IPv4 listener
     /// here, not an IPv6 one, matching how the runtime already reads it.
     ///
+    /// A lone explicit dual-stack `[::]:PORT` listener is not the recommended
+    /// configuration when reply DSCP/traffic-class marking for IPv4 peers
+    /// matters: Linux serves those peers as IPv4-mapped and cannot retain the
+    /// negotiated marking on their replies. Request the normal same-port
+    /// `[::]:PORT` and `0.0.0.0:PORT` pair instead. This method makes the IPv6
+    /// half IPv6-only for that pair only; a lone IPv6 listener retains its
+    /// normal socket behavior.
+    ///
     /// # Errors
     ///
     /// Returns [`ServerSetError::NoListeners`] if `addrs` is empty — a set

docs/INTEROP_COMPARISON.md

@@ -139,5 +139,5 @@ scenario contains the existing comparison harness output under
 `netem-summary.json` files. Server stdout/stderr are captured at the run root as
 `server.stdout` and `server.stderr`.
 
-On macOS, `ip netns` and `tc netem` are unavailable; use the GitHub Actions
+On macOS, `ip netns` and `tc netem` are unavailable; use the Gitea Actions
 workflow for netem coverage.

docs/irtt-client.md

@@ -6,7 +6,7 @@ irtt-client - IRTT-compatible stream client
 
 ## SYNOPSIS
 
-`irtt-client` [*OPTIONS*] [*[LABEL=]TARGET*]...
+`irtt-client` [*OPTIONS*] [*[LABEL=]TARGET[@hmac=KEY]*]...
 
 `irtt-client` `--list-columns`
 
@@ -18,17 +18,39 @@ eligible runs.
 
 ## TARGETS
 
-Every target argument accepts `[LABEL=]TARGET`. An optional `LABEL=` prefix
+Every target argument accepts `[LABEL=]TARGET[@hmac=KEY]`. An optional
-assigns the logical target name used in output; without it, the target
+`LABEL=` prefix assigns the logical target name used in output; without it,
-string itself is used as the label. Labeled and unlabeled targets can be
+the target string itself is used as the label. Labeled and unlabeled targets
-freely mixed in one argument list.
+can be freely mixed in one argument list. Prefer explicit labels for
+long-running dynamic target sets: the label is the stable target identity
+across replacements.
 
 ```sh
 irtt-client host-a:2112
 irtt-client eu=host-a:2112 us=host-b:2112
 irtt-client host-a:2112 eu=host-b:2112
+irtt-client --hmac default-secret eu=host-a:2112@hmac=eu-secret public=host-b:2112@hmac=
 ```
 
+Targets without `@hmac=` inherit the global `--hmac` value. `@hmac=KEY`
+overrides it for that target, and `@hmac=` explicitly disables HMAC for that
+target. The modifier uses `@`, not a shell command separator; quote an argument
+if its key needs shell quoting.
+
+Target syntax supports these backslash escapes in labels, addresses, and HMAC
+values: `\\` for a literal backslash, `\@` for a literal `@`, `\=` for a
+literal `=`, and `\;` for a literal semicolon. Escaping `@` is necessary in a
+label or address when it would otherwise begin `@hmac=`; escaping the first
+`=` is how an unlabeled target or a label can contain that character. An `=` in
+an HMAC value, including Base64 padding, does not need escaping. Positional
+target arguments may contain a raw comma; stdin target sets have the additional
+`\,` escape described below.
+
+Shells process unquoted backslashes and characters such as semicolons before
+the client sees them. Single-quote a target when it contains parser escapes,
+for example `'west\=edge=host\@hmac=literal@hmac=a\;b\\c'`, so the
+backslashes reach `irtt-client` unchanged.
+
 Multiple targets are probed concurrently. By default, a multi-target session
 uses **staggered** pacing, spacing active targets across the probe interval;
 pass `--pacing burst` to send one probe to every active target back-to-back
@@ -36,6 +58,57 @@ once per interval instead. Final per-target summaries print in the order
 targets were supplied on the command line, not the order in which they
 finish or their labels sort alphabetically.
 
+## DYNAMIC TARGET SETS FROM STANDARD INPUT
+
+`--targets-stdin` is available only with continuous mode (`--duration 0`).
+Positional targets remain an initial desired set, and may be omitted to
+start empty:
+
+~~~sh
+irtt-client --duration 0 --targets-stdin
+irtt-client --duration 0 --targets-stdin ams=ams.example:2112
+~~~
+
+Each non-empty stdin record declares the complete desired target set, rather
+than a delta. A later record replaces an earlier set: targets absent from it
+are retired, unchanged target configurations retain their generation, and a
+changed address or HMAC setting creates a fresh generation. Under transient
+live-generation backpressure, only the latest unapplied desired set is kept.
+
+Commas frame targets in stdin records; escape a literal comma within one
+target as `\,`. Target parsing inside each element is otherwise the same as
+for positional arguments, including the other escapes above, `@hmac=KEY`, and
+`@hmac=`. Use a persistent producer or keep a pipe/FIFO writer open while the
+client is being controlled. For example, in one terminal:
+
+~~~sh
+mkfifo /tmp/irtt-targets
+irtt-client --duration 0 --targets-stdin --hmac default-secret \
+  < /tmp/irtt-targets
+~~~
+
+Then open the FIFO once from another terminal and keep that descriptor open
+while publishing complete desired sets:
+
+~~~sh
+exec 3> /tmp/irtt-targets
+printf '%s\n' 'ams=ams.example:2112,sg=sg.example:2112@hmac=sg-secret' >&3
+printf '%s\n' 'sg=sg.example:2112@hmac=sg-secret,nyc=nyc.example:2112' >&3
+# Publish more sets as needed, then send EOF and stop the client:
+exec 3>&-
+~~~
+
+The exact record `[]` selects an empty desired set. Empty records are
+ignored; whitespace is otherwise payload, not trimming. EOF is immediate loss
+or closure of the control plane and requests a graceful stop. A desired-state
+revision that was read but has not yet been acknowledged as applied may be
+discarded when EOF is observed; EOF does not wait for a capacity-rejected
+revision to become applicable.
+
+The maximum stdin record payload is 64 KiB. Stdin-controlled mode bounds each
+desired set to 128 targets and retains at most 256 live target generations
+while replacements drain.
+
 ## FINITE VERSUS CONTINUOUS OPERATION
 
 `--duration` controls the run length:
@@ -45,8 +118,9 @@ finish or their labels sort alphabetically.
   (see [OUTPUT](#output) below — CSV, TSV, and JSON Lines never print one).
 - `--duration 0` is **continuous**: the client runs until interrupted
   (`Ctrl-C`). For table output, a final summary is printed only if the run
-  was interrupted; an uninterrupted continuous run (one that exits for
+  was interrupted. Stdin-controlled mode is the exception: EOF also requests
-  another reason) does not get one.
+  a graceful stop and prints the final retained summary. An uninterrupted
+  continuous run that exits for another reason does not get one.
 
 See [MEASUREMENTS AND MEMORY](#measurements-and-memory) below for why this
 distinction also determines what statistics can be computed and how much
@@ -192,6 +266,10 @@ the client exits nonzero — so a process supervisor can restart it; an
 interrupted run (`Ctrl-C`) never reports peer closure as an error, whichever
 mode it was in.
 
+With `--targets-stdin`, peer closure is target-local: other desired targets
+and the stdin controller continue running. Including that target in a later
+complete set starts a fresh generation.
+
 ## EXIT STATUS
 
 `0` on success (including a finite run's ordinary completion, and an

docs/irtt-rs.md

@@ -31,7 +31,7 @@ The build also produces dedicated binaries: `irtt-client`, `irtt-tui`, and
 what it is invoked or copied as — it does not consult argv0 dispatch logic.
 
 `irtt-rs` itself inspects argv0 first: if invoked (or symlinked/copied) under
-one of the recognized applet names — `irtt-client`, `irtt-tui`, `irttd`, or
+one of the recognized applet names — `irtt-client`, `irtt-tui`, or
 `irtt-server` — it runs that applet directly, without needing a subcommand.
 Any other name starting with `irtt-` (other than `irtt-rs` itself) is
 rejected as an unknown applet name before subcommand parsing is even

docs/irtt-server.md

@@ -60,7 +60,17 @@ served.
 A port of `0` selects an unused port per listener, so two such binds get two
 different ports.
 
-With no `--bind` at all, see [Default bind](#default-bind) above.
+With no `--bind` at all, see [Description](#description) above for the
+default wildcard pair and the address-family fallback it allows.
+
+When reply DSCP/traffic-class marking for IPv4 peers matters, do not configure
+one explicit dual-stack `[::]:PORT` listener by itself. On Linux, IPv4 peers
+served through that socket are IPv4-mapped and their replies cannot retain the
+negotiated marking. Configure the ordinary paired `[::]:PORT` and
+`0.0.0.0:PORT` listeners instead; the IPv6 listener is made IPv6-only for that
+same-port pair, so each family uses the correct socket option. This is a
+configuration workaround, not a reason to force `IPV6_V6ONLY` for every lone
+IPv6 listener.
 
 ### `--hmac KEY`
 
@@ -136,6 +146,35 @@ and they are sent unmarked. The session is not refused.
 Durations everywhere in this command accept an integer followed by a unit:
 `ms`, `s`, or `m`.
 
+## ENVIRONMENT
+
+Every option above can also be supplied through an environment variable, for
+deployments that configure by environment rather than by command line
+(containers, orchestrators, unit files). A flag given on the command line
+overrides the corresponding variable entirely; an unset variable leaves the
+built-in default in place.
+
+| Variable | Option |
+| --- | --- |
+| `IRTT_SERVER_BIND` | `--bind`, one address only |
+| `IRTT_SERVER_HMAC` | `--hmac` |
+| `IRTT_SERVER_MAX_SESSIONS` | `--max-sessions` |
+| `IRTT_SERVER_MAX_PACKET_LENGTH` | `--max-packet-length` |
+| `IRTT_SERVER_MIN_INTERVAL` | `--min-interval` |
+| `IRTT_SERVER_BURST` | `--burst` |
+| `IRTT_SERVER_IDLE_TIMEOUT` | `--idle-timeout` |
+| `IRTT_SERVER_MAX_DURATION` | `--max-duration` |
+| `IRTT_SERVER_TIMESTAMP_ALLOWANCE` | `--timestamp-allowance` |
+| `IRTT_SERVER_NO_DSCP` | `--no-dscp` |
+
+`IRTT_SERVER_BIND` takes exactly one address, the same as a single `--bind`;
+there is no way to request several listeners from the environment. Serving
+more than one address needs repeated `--bind` options.
+
+`IRTT_SERVER_NO_DSCP` is the only boolean. `0`, `false`, `no`, `n`, `off` and
+an empty value leave traffic-class marking enabled; any other value disables
+it, and an unset variable leaves it enabled.
+
 ## OUTPUT
 
 Each bound endpoint is printed on startup, once every listener is up, which

docs/irtt-tui.md

@@ -62,6 +62,14 @@ presentation bounds on top of the client's own statistics retention (see
 total memory is dominated by whichever of the two is larger for your target
 count.
 
+A **finite** `--duration` TUI run retains exact statistics samples exactly as
+`irtt-client(1)` does in finite mode, so its retained state grows with the
+probe count rather than approaching a bound. Unlike `irtt-client`, the TUI
+prints **no** memory warning when that estimate gets large: it owns the
+alternate screen, and a stderr warning there would be invisible or would
+corrupt the display. Size a long finite TUI run from the figures in
+`irtt-client(1)` MEASUREMENTS AND MEMORY, or use the continuous default.
+
 ## EXIT BEHAVIOR
 
 Quitting with `q` or `Ctrl-C` is an interrupted, successful exit. Otherwise,

fuzz/Cargo.lock

@@ -8,6 +8,18 @@ version = "1.4.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "c3d036a3c4ab069c7b410a2ce876bd74808d2d0888a82667669f8e783a898bf1"
 
+[[package]]
+name = "autocfg"
+version = "1.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f2032f911046de80f0a198e0901378627c33f59ea0ac00e363d481118bd70a53"
+
+[[package]]
+name = "bitflags"
+version = "2.13.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3ded4057c258ba199e2d26386d3af3780957ecaee6c4ef4041c6b4b8b97c0b06"
+
 [[package]]
 name = "block-buffer"
 version = "0.12.1"
@@ -19,9 +31,9 @@ dependencies = [
 
 [[package]]
 name = "cc"
-version = "1.4.3"
+version = "1.4.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "509591b7bcd67f4ef775afad7662703b4935daaa6ec0e5605cfb1090b32a2b6d"
+checksum = "0ad534f4357a5264cce5019c989cf66a4f0dc4e0d1b1d15f8aacec0ff7360273"
 dependencies = [
  "find-msvc-tools",
  "jobserver",
@@ -35,6 +47,12 @@ version = "1.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9330f8b2ff13f34540b44e946ef35111825727b38d33286ef986142615121801"
 
+[[package]]
+name = "cfg_aliases"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f079e83a288787bcd14a6aea84cee5c87a67c5a3e660c30f557a3d24761b3527"
+
 [[package]]
 name = "cmov"
 version = "0.5.4"
@@ -126,10 +144,24 @@ dependencies = [
 name = "irtt-proto-fuzz"
 version = "0.0.0"
 dependencies = [
+ "arbitrary",
  "irtt-proto",
+ "irtt-server",
  "libfuzzer-sys",
 ]
 
+[[package]]
+name = "irtt-server"
+version = "0.5.2"
+dependencies = [
+ "getrandom",
+ "irtt-proto",
+ "nix",
+ "socket2",
+ "thiserror",
+ "tokio",
+]
+
 [[package]]
 name = "jobserver"
 version = "0.1.35"
@@ -166,6 +198,45 @@ dependencies = [
  "digest",
 ]
 
+[[package]]
+name = "memoffset"
+version = "0.9.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "488016bfae457b036d996092f6cb448677611ce4449e970ceaf42695203f218a"
+dependencies = [
+ "autocfg",
+]
+
+[[package]]
+name = "mio"
+version = "1.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4b18443e9c262bfe8fa82f51666e2642c53393f7e5c27b3e1aeab922cff5b9d8"
+dependencies = [
+ "libc",
+ "wasi",
+ "windows-sys",
+]
+
+[[package]]
+name = "nix"
+version = "0.31.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cf20d2fde8ff38632c426f1165ed7436270b44f199fc55284c38276f9db47c3d"
+dependencies = [
+ "bitflags",
+ "cfg-if",
+ "cfg_aliases",
+ "libc",
+ "memoffset",
+]
+
+[[package]]
+name = "pin-project-lite"
+version = "0.2.17"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a89322df9ebe1c1578d689c92318e070967d1042b512afbe49518723f4e6d5cd"
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.107"
@@ -196,6 +267,16 @@ version = "2.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f8fadd59c855ef2080decdef8ff161eb6661b86933c9d82e5ba29dc602a55aba"
 
+[[package]]
+name = "socket2"
+version = "0.6.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c3d1e2c7f27f8d4cb10542a02c49005dbd6e93095799d6f3be745fae9f8fedd4"
+dependencies = [
+ "libc",
+ "windows-sys",
+]
+
 [[package]]
 name = "subtle"
 version = "2.6.1"
@@ -204,9 +285,9 @@ checksum = "13c2bddecc57b384dee18652358fb23172facb8a2c51ccc10d74c157bdea3292"
 
 [[package]]
 name = "syn"
-version = "3.0.3"
+version = "3.0.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "53e9bae58849f64dfa4f5d5ae372c8341f7305f82a3868709269343628b659a3"
+checksum = "e6275cddf4610d1775e6d1fe9469b2e77d0f39fd98fb7450901b821e0c53649f"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -233,6 +314,31 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "tokio"
+version = "1.53.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "202caea871b69668250d242070849eb495be178ed697a3e98aebce5bc81a0bed"
+dependencies = [
+ "libc",
+ "mio",
+ "pin-project-lite",
+ "socket2",
+ "tokio-macros",
+ "windows-sys",
+]
+
+[[package]]
+name = "tokio-macros"
+version = "2.7.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "78773a2a397f451582ce068015985c33193cf6dea8b74d2a639fe457b2f07b0e"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "typenum"
 version = "1.20.1"
@@ -244,3 +350,24 @@ name = "unicode-ident"
 version = "1.0.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e6e4313cd5fcd3dad5cafa179702e2b244f760991f45397d14d4ebf38247da75"
+
+[[package]]
+name = "wasi"
+version = "0.11.1+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ccf3ec651a847eb01de73ccad15eb7d99f80485de043efb2f370cd654f4ea44b"
+
+[[package]]
+name = "windows-link"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f0805222e57f7521d6a62e36fa9163bc891acd422f971defe97d64e70d0a4fe5"
+
+[[package]]
+name = "windows-sys"
+version = "0.61.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ae137229bcbd6cdf0f7b80a31df61766145077ddf49416a728b02cb3921ff3fc"
+dependencies = [
+ "windows-link",
+]

fuzz/Cargo.toml

@@ -8,11 +8,15 @@ edition = "2021"
 cargo-fuzz = true
 
 [dependencies]
-libfuzzer-sys = "0.4"
+arbitrary = "1.4.2"
+libfuzzer-sys = "0.4.13"
 
 [dependencies.irtt-proto]
 path = "../crates/irtt-proto"
 
+[dependencies.irtt-server]
+path = "../crates/irtt-server"
+
 # Use independent workspace for fuzzers
 [workspace]
 members = ["."]
@@ -51,3 +55,10 @@ path = "fuzz_targets/decode_varint.rs"
 test = false
 doc = false
 bench = false
+
+[[bin]]
+name = "server_core_datagrams"
+path = "fuzz_targets/server_core_datagrams.rs"
+test = false
+doc = false
+bench = false

fuzz/README.md

@@ -1,6 +1,7 @@
-# `irtt-proto` fuzzing
+# `irtt-rs` fuzzing
 
-Coverage-guided fuzzing of `irtt-proto`'s wire decoders via
+Coverage-guided fuzzing of `irtt-proto` wire decoders and `irtt-server`'s public
+`ServerCore::handle_datagram` API via
 [`cargo-fuzz`](https://github.com/rust-fuzz/cargo-fuzz)/libFuzzer.
 
 This project is intentionally isolated from the normal stable/MSRV
@@ -22,14 +23,16 @@ of the root workspace, requires nightly Rust, and is not built by
 | `decode_echo_reply` | `decode_echo_reply` against a deterministic, bounded `Params` matrix, unauthenticated and HMAC-authenticated |
 | `decode_params`     | `Params::decode` and `Params::decode_with_presence`, plus an encode/decode round trip |
 | `decode_varint`     | `varint::decode_uvarint`/`decode_varint` and their round trip through `encode_uvarint`/`encode_varint` |
+| `server_core_datagrams` | A bounded mix of raw datagrams and production-encoded Open/Echo/Close requests against one `ServerCore`; it varies IPv4/IPv6 peers, session configuration, and bounded (up to 128-byte) HMAC keys, authenticates keyed requests, reuses issued tokens, and asserts the session cap |
 
 The invariant every target asserts is: **arbitrary bytes must never panic**.
 Returning `Err` is normal and expected; a successful decode is also normal.
 
-Every target bounds its input to 128 KiB (`MAX_INPUT_LEN` in each harness) so
+Every target bounds its input (`MAX_INPUT_LEN` in each harness) so libFuzzer
-libFuzzer spends its time exploring protocol structure rather than
+spends its time exploring protocol structure rather than allocating/copying
-allocating/copying megabytes — production IRTT datagrams are UDP-sized, well
+megabytes. `server_core_datagrams` additionally caps its sequence length and
-under this bound.
+each individual datagram and configures the core to the same packet cap, so one
+libFuzzer input cannot become a tiny DoS benchmark.
 
 ## Running
 

fuzz/fuzz_targets/server_core_datagrams.rs

@@ -0,0 +1,186 @@
+#![no_main]
+
+use std::{
+    net::{IpAddr, Ipv4Addr, Ipv6Addr, SocketAddr},
+    time::Duration,
+};
+
+use arbitrary::Unstructured;
+use irtt_proto::{decode_open_reply, encode_request, Params, RequestToEncode};
+use irtt_server::{ServerConfig, ServerCore};
+use libfuzzer_sys::fuzz_target;
+
+/// Bounds one libFuzzer input as well as the work it can ask the core to do.
+/// These are deliberately much smaller than a production UDP payload: the
+/// target is stateful parser/session exploration, not packet-size throughput.
+const MAX_INPUT_LEN: usize = 32 * 1024;
+const MAX_DATAGRAMS: usize = 16;
+const MAX_DATAGRAM_LEN: usize = 2 * 1024;
+const MAX_SESSIONS: u8 = 8;
+const MAX_HMAC_KEY_LEN: usize = 128;
+
+#[derive(Clone)]
+struct FuzzSession {
+    token: u64,
+    peer: SocketAddr,
+    params: Params,
+}
+
+fuzz_target!(|data: &[u8]| {
+    if data.len() > MAX_INPUT_LEN {
+        return;
+    }
+
+    let mut input = Unstructured::new(data);
+    let Ok(mut config) = config(&mut input) else {
+        return;
+    };
+    let hmac_key = match input.arbitrary::<bool>() {
+        Ok(true) => {
+            let Ok(length) = input.int_in_range(1..=MAX_HMAC_KEY_LEN) else {
+                return;
+            };
+            input.bytes(length).ok()
+        }
+        Ok(false) => None,
+        Err(_) => return,
+    };
+    if let Some(key) = hmac_key {
+        config = config.with_hmac_key(key);
+    }
+    let mut core = ServerCore::new(config);
+    let mut sessions = Vec::new();
+
+    for _ in 0..MAX_DATAGRAMS {
+        let Ok(operation) = input.arbitrary::<u8>() else {
+            break;
+        };
+
+        match operation % 4 {
+            // Keep arbitrary-byte admission coverage alongside the stateful
+            // production-encoded requests below.
+            0 => raw_datagram(&mut core, &mut input),
+            1 => open_session(&mut core, &mut input, hmac_key, &mut sessions),
+            2 => echo_session(&mut core, &mut input, hmac_key, &sessions),
+            _ => close_session(&mut core, &mut input, hmac_key, &mut sessions),
+        }
+
+        // Arbitrary network input is expected to be rejected or to produce an
+        // internal error in exceptional host conditions. It must never panic,
+        // and it may never grow the bounded table past its configured cap.
+        assert!(core.session_count() <= core.config().max_sessions());
+    }
+});
+
+fn config(input: &mut Unstructured<'_>) -> arbitrary::Result<ServerConfig> {
+    let max_sessions = usize::from(input.int_in_range(0..=MAX_SESSIONS)?);
+    Ok(ServerConfig::default()
+        .with_max_sessions(max_sessions)
+        .with_max_packet_length(MAX_DATAGRAM_LEN)
+        .with_min_send_interval(Duration::ZERO))
+}
+
+fn raw_datagram(core: &mut ServerCore, input: &mut Unstructured<'_>) {
+    let (Ok(peer), Ok(length)) = (peer(input), input.int_in_range(0..=MAX_DATAGRAM_LEN)) else {
+        return;
+    };
+    let Ok(packet) = input.bytes(length) else {
+        return;
+    };
+    let _ = core.handle_datagram(peer, packet);
+}
+
+fn open_session(
+    core: &mut ServerCore,
+    input: &mut Unstructured<'_>,
+    hmac_key: Option<&[u8]>,
+    sessions: &mut Vec<FuzzSession>,
+) {
+    let Ok(peer) = peer(input) else {
+        return;
+    };
+    let params = session_params();
+    let request = encode_request(
+        RequestToEncode::Open {
+            params: &params,
+            no_test: false,
+        },
+        hmac_key,
+    )
+    .expect("fixed valid fuzz open must encode");
+    let Ok(Some(reply)) = core.handle_datagram(peer, &request) else {
+        return;
+    };
+    let Ok(reply) = decode_open_reply(reply.bytes(), hmac_key) else {
+        return;
+    };
+    sessions.push(FuzzSession {
+        token: reply.token,
+        peer,
+        params: reply.params,
+    });
+}
+
+fn echo_session(
+    core: &mut ServerCore,
+    input: &mut Unstructured<'_>,
+    hmac_key: Option<&[u8]>,
+    sessions: &[FuzzSession],
+) {
+    let Some(session) =
+        sessions.get(usize::from(input.arbitrary::<u8>().unwrap_or(0)) % sessions.len().max(1))
+    else {
+        return;
+    };
+    let sequence = input.arbitrary().unwrap_or_default();
+    let request = encode_request(
+        RequestToEncode::Echo {
+            token: session.token,
+            sequence,
+            params: &session.params,
+            payload: &[],
+        },
+        hmac_key,
+    )
+    .expect("fixed valid fuzz echo must encode");
+    let _ = core.handle_datagram(session.peer, &request);
+}
+
+fn close_session(
+    core: &mut ServerCore,
+    input: &mut Unstructured<'_>,
+    hmac_key: Option<&[u8]>,
+    sessions: &mut Vec<FuzzSession>,
+) {
+    let index = usize::from(input.arbitrary::<u8>().unwrap_or(0)) % sessions.len().max(1);
+    let Some(session) = sessions.get(index) else {
+        return;
+    };
+    let request = encode_request(
+        RequestToEncode::Close {
+            token: session.token,
+        },
+        hmac_key,
+    )
+    .expect("fixed valid fuzz close must encode");
+    let _ = core.handle_datagram(session.peer, &request);
+    sessions.swap_remove(index);
+}
+
+fn session_params() -> Params {
+    Params {
+        protocol_version: 1,
+        length: 256,
+        ..Params::default()
+    }
+}
+
+fn peer(input: &mut Unstructured<'_>) -> arbitrary::Result<SocketAddr> {
+    let port = input.arbitrary()?;
+    let address = if input.arbitrary()? {
+        IpAddr::V4(Ipv4Addr::from(input.arbitrary::<[u8; 4]>()?))
+    } else {
+        IpAddr::V6(Ipv6Addr::from(input.arbitrary::<[u8; 16]>()?))
+    };
+    Ok(SocketAddr::new(address, port))
+}