feat(adr-118/p1.3): Sink marker traits + PrivacyClass::try_from (17/17 GREEN)
Iter 3. Lands the structural enforcement of ADR-118 invariant I1
("raw BFI never exits the node") and ADR-120 §2.2 ("Sink marker types").
Added:
- src/sink.rs:
* Sink trait with MIN_CLASS and KIND associated constants
* LocalSink (Raw OK), NetworkSink (Derived+ only), MatterSink (Anonymous+)
* Hierarchy: MatterSink: NetworkSink (every Matter sink is a NetworkSink)
* check_class<S>(class) runtime gate, returns PrivacyViolation{reason:KIND}
* Zero-sized kind tags: LocalKind / NetworkKind / MatterKind
- PrivacyClass::as_u8() const helper
- TryFrom<u8> for PrivacyClass (0..=3 valid; 4..=255 → InvalidPrivacyClass)
- BfldError::InvalidPrivacyClass(u8) variant
tests/sink_enforcement.rs adds 8 tests:
privacy_class_try_from_accepts_all_four_valid_bytes
privacy_class_try_from_rejects_out_of_range_bytes
privacy_class_byte_roundtrip_is_stable
local_sink_accepts_all_classes
network_sink_rejects_raw_frames
network_sink_accepts_derived_anonymous_restricted
matter_sink_rejects_raw_and_derived
matter_sink_accepts_anonymous_and_restricted
Out of scope (next iter):
- BfldFrame (header + payload + section length-prefixes + CRC32 over payload)
— needs the `crc` crate dependency.
- PrivacyGate::demote(frame, target_class) transformer (ADR-120 §2.4).
- compile-fail test that proves a sink-trait bound rejects Raw at compile
time — needs `trybuild` integration; deferred to a separate iter.
cargo test -p wifi-densepose-bfld --no-default-features → 17 passed, 0 failed
(3 frame_header_size + 6 header_roundtrip + 8 sink_enforcement)
Co-Authored-By: claude-flow <ruv@ruv.net>
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