feat: forward-port per-source RX demux (v0.7.3) onto 0.8.0

[JustinKovacich]

Forward-ports the two v0.7.3 feature commits (cb6e3bd, 662662b) onto the 0.8.0 spine, so the 0.8.0 release doesn't regress per-source RX demux. The 0.7.3 release itself lives only on the release/0.7.2 line (PR #136); this is its 0.8.0 equivalent, the sibling of #135 (which forward-ported 0.7.2).

Stacked on #135. Base is feat/port_publish_raw_event_to_onto_0_8_0; the chore: release v0.7.3 commit is intentionally dropped.

What

1. ClientUpdate::Unicast now carries source: SocketAddr. The source was already received on ReceivedMessage.source but dropped via .. before forwarding. On a shared subnet the SOME/IP header has no instance id, so the source address is the only demux key. (Clean cherry-pick modulo the send → send_now rename from Reduce async state and static pool memory in simple_someip to prevent Embassy arena exhaustion #125.)

2. RX E2E counter state is keyed per (source, key). E2ERegistry splits into endpoint-agnostic profile config + per-(source, key) receive state + per-key transmit state. check() now takes the source IP; protect() is unchanged (fan-out keeps one TX counter; per-recipient TX lives a layer up). A rebooted source's receive state is reset.

Forward-port adaptation (differs materially from the 0.7.3 diff)

The 0.7.3 commit assumed std::HashMap and a free process_discovery(&Arc<Mutex<E2ERegistry>>, …) function. Neither exists on the 0.8.0 spine, so the port was re-authored against the post-#18/#125 surface:

• Registry is heapless::FnvIndexMap, not HashMap. All three maps are fixed-capacity and const-constructible (no_std, heap-free). Profile/TX bounded by E2E_REGISTRY_CAP; RX bounded by a new E2E_RX_STATE_CAP (64).
• E2ERegistryHandle gained source on check + a new reset_source, propagated through all three impls (Arc<Mutex>, StaticE2EHandle, NullE2ERegistry).
• Reboot reset is inline, at the run loop's existing if rebooted site (inner.rs), via the R: E2ERegistryHandle handle — there is no process_discovery to thread a registry through on this spine.
• Dropped: the unicast-SD discovery-domain arm. 662662b also added a second SD receive arm (discovery_unicast_socket / TransportKind::Unicast); that infrastructure isn't on the 0.8.0 spine and is outside the per-source-E2E feature. Not ported here.

Design decision worth a look — RX saturation policy

rx_states is bounded (E2E_RX_STATE_CAP = 64), unlike the original unbounded HashMap. When full, a brand-new (source, key) can't claim a slot, so check() falls back to a transient per-call counter: CRC is still validated, only sequence continuity is untracked for that source until a slot frees (reset_source / unregister). A one-shot warn! fires the first time (mirrors the session.rs saturation latch). Sizing and this policy are the two things to sanity-check for the target subnet.

Verification

• cargo clippy --workspace --all-features -- -D warnings -D clippy::pedantic ✅
• cargo clippy --no-default-features --features client,bare_metal (and server,bare_metal, client,server,bare_metal) pedantic ✅
• cargo build --target thumbv7em-none-eabihf --no-default-features --features client,bare_metal ✅
• no_alloc_witness (StaticE2EHandle check/protect) — still zero heap alloc on the per-source path ✅
• registry unit tests (incl. new distinct_sources_have_independent_e2e_state, reset_source_clears_only_that_source) ✅
• client_server + bare_metal_e2e + doctests ✅ (client_server passes single-threaded; the parallel run hits the known pre-existing fixture-collision flake)

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Forward-ports the per-source RX demux work onto the 0.8.0 codebase by preserving sender identity on unicast updates and keying E2E receive state per source, while also expanding the crate’s no_std/bare-metal tooling, transport surface, and examples to support/verify these paths across targets.

Changes:

• Preserve unicast sender identity by adding source: SocketAddr to ClientUpdate::Unicast and forwarding it from the client run loop.
• Key E2E RX counter state per (source, key) with bounded receive-state storage and a reset_source hook for sender reboots.
• Broaden bare-metal/no_std support & verification (buffer pools, callback transport/mailbox runtime pieces, embassy-net adapter crate, probes, docs/tests).

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
tools/size_probe/Cargo.toml	Adds standalone no_std staticlib probe manifest for size/type-layout measurement.
tools/size_probe/Cargo.lock	Locks probe dependencies for repeatable measurement builds.
tools/capture_type_sizes.sh	Script to capture -Zprint-type-sizes for host/thumb and summarize results.
tests/no_alloc_server_witness.rs	Adds no-alloc witness for server-side static subscription handle hot paths.
tests/data/vsomeip-offerer/subscriber.json	Adds vsomeip subscriber config for TX-direction SD conformance testing.
tests/data/vsomeip-offerer/subscriber.cpp	Adds vsomeip subscriber binary used by SD compatibility tests.
tests/data/vsomeip-offerer/README.md	Documents building/running the vsomeip conformance Docker image and tests.
tests/data/vsomeip-offerer/offerer.json	Updates vsomeip offerer config (multicast group alignment commentary).
tests/data/vsomeip-offerer/offerer.cpp	Updates/minimizes offerer implementation and logs for test scraping.
tests/data/vsomeip-offerer/entrypoint.sh	Adds entrypoint templating logic for vsomeip role configs.
tests/data/vsomeip-offerer/Dockerfile	Builds pinned vsomeip + offerer/subscriber binaries for conformance testing.
tests/data/vsomeip-offerer/CMakeLists.txt	Builds both vsomeip helper binaries against installed vsomeip3.
tests/buffer_pool.rs	Adds tests for the new fixed-capacity BufferPool claim/release behavior.
tests/bare_metal_example_builds.rs	Canary test documenting that bare-metal example crates must compile.
tests/bare_metal_client.rs	Witness test for constructing/running client without client-tokio using static channels.
tests/bare_metal_client_local.rs	Witness test for local-spawner client construction (new_with_deps_local).
src/traits.rs	Makes SD helpers more no_std-friendly (visitor APIs, core net types, default no-op hook).
src/server/service_info.rs	Gates std-only service/event-group info types; uses core::net where possible.
src/server/README.md	Updates server docs for the new announcement loop spawning API and subscription APIs.
src/server/error.rs	Expands server error taxonomy (Transport/Capacity/InvalidUsage) with cfg(std) IO.
src/raw_payload.rs	Switches SD endpoint/service extraction to visitor pattern for no_std compatibility.
src/protocol/sd/test_support.rs	Aligns test payload SD header construction with core types and new trait surface.
src/protocol/sd/options.rs	Minor doc fix to avoid broken intra-doc link formatting.
src/protocol/sd/header.rs	Minor numeric literal formatting cleanup in tests.
src/protocol/message_type.rs	Fixes wire encoding for message type field (Response/Error bytes) + regression test.
src/protocol/message_id.rs	Moves/adds Debug impl for MessageId (formatting consistency noted in review).
src/protocol/header.rs	Adds upper_header_bytes() accessor and restores WireFormat impl placement.
src/protocol/byte_order.rs	Adds clippy allow for float cmp in byte-level roundtrip tests.
src/log.rs	Introduces internal logging shim to avoid tracing/alloc requirements on some no_std targets.
src/heapless_payload.rs	Adds alloc-free PayloadWireFormat implementation for bare-metal payload handling.
src/e2e/mod.rs	Makes registry/state available beyond std and re-exports registry constants/types.
src/e2e/e2e_protector.rs	Formatting-only test constant literal updates.
src/e2e/e2e_checker.rs	Routes warnings through logging shim; formatting-only test updates.
src/e2e/crc.rs	Routes traces through logging shim; formatting-only test updates.
src/client/session.rs	Replaces HashMap with bounded FnvIndexMap for session tracking; saturation behavior docs/tests.
src/client/service_registry.rs	Makes service registry heap-free via FnvIndexMap, adds capacity error path + tests.
src/client/error.rs	Refines client error taxonomy (Capacity/Transport/Shutdown) and adds display regression tests.
src/client/bind_dispatch.rs	Adds spawner-agnostic bind+spawn abstraction shared by Send and !Send client constructions.
src/buffer_pool.rs	Adds fixed-capacity buffer pool with RAII leases for no-alloc socket loops.
src/bare_metal_runtime/transport.rs	Adds callback-driven transport/timer implementations for bare-metal runtime integration.
src/bare_metal_runtime/mod.rs	Adds bare-metal runtime module surface exports and feature-gated runtime glue.
src/bare_metal_runtime/mailbox.rs	Adds shared RX mailbox for callback transport (bounded slots/capacity) + tests.
simple-someip-embassy-net/src/socket.rs	Adds embassy-net TransportSocket adapter with named futures for zero-alloc send/recv.
simple-someip-embassy-net/src/lib.rs	New no_std adapter crate surface and MTU guidance.
simple-someip-embassy-net/README.md	Documents adapter usage and status.
simple-someip-embassy-net/Cargo.toml	Adds new adapter crate manifest with pinned embassy-net deps and host test deps.
README.md	Updates crate README for 0.8 feature split, transport traits, and run-loop spawning requirements.
examples/embassy_net_client/Cargo.toml	Adds host example wiring simple-someip through the embassy-net adapter.
examples/discovery_client/src/main.rs	Updates example to spawn the client run-loop future returned by Client::new.
examples/discovery_client/Cargo.toml	Updates example to depend on client-tokio (constructor availability).
examples/client_server/src/main.rs	Updates hybrid example to new SD announcement loop API and server config shape.
examples/client_server/Cargo.toml	Updates example to client-tokio/server-tokio features.
examples/bare_metal_server/src/main.rs	Adds host-side example for no-tokio bare-metal server construction/run.
examples/bare_metal_server/Cargo.toml	Adds bare-metal server example manifest with appropriate feature pins.
examples/bare_metal_client/Cargo.toml	Adds bare-metal client example manifest with appropriate feature pins.
docs/simple_someip/plans/2026-06-17-pr126-polled-port-handoff.md	Adds planning/handoff notes for future polled bare-metal port work.
docs/simple_someip/plans/2026-06-10-pr1-124-followups-design.md	Adds design doc covering callback shape, docs, tests, and error-handling decisions.
Cargo.toml	Expands workspace members, adds feature split (*-tokio), adds bare-metal runtime deps, excludes probe.
.gitignore	Updates ignore list for probe targets and generated Claude artifacts.
.config/nextest.toml	Adds nextest serialization groups to prevent static pool exhaustion in parallel runs.

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[JustinKovacich]

Folded into #138. The 0.8.0 forward-port stack was consolidated via a linear rebase of the whole stack onto main (which now includes #130). #138 is rebased onto main and carries this branch's commits intact — closing here to collapse the stack into a single PR. Verified: 556 all-features lib tests, client_server 11/11, all 5 CI clippy lanes, no_alloc_witness, bare_metal_e2e 9/9.