NDN Specification Compliance

As of 2026-05-13, the compliance picture for ndn-rs is substantially improved from the initial April audit state. Of 126 findings across phases A–I in docs/notes/spec-compliance-audit-2026-04-20.md, 106 findings in phases A–H are resolved with at least a code fix or documented as positive on re-verification, including all 21 in Phase A, 11 of 12 in Phase B, 18 of 19 in Phase D, all 9 in Phase G, all 13 in Phase F, and 10 of 11 in Phase H (per-phase counts in the table below sum to 106). All Phase I findings (14) were architectural misunderstandings cleared on the audit pass itself. Six of those resolutions — D.01 (HopLimit decrement), D.02 (/localhop scope), E.01 (management signing), E.04 (segmented datasets), G.04 phase 1 (NLSR LSA wire format), and G.04 full NLSR interop — have been witnessed against C++ NFD or C++ NLSR via the live testbed harness at testbed/tests/. The remaining open findings are categorised below. Wire compatibility claims on this page are backed by scripts in testbed/tests/audit/ (per-finding unit and GREP-PROOF witnesses) and testbed/tests/interop/ (cross-implementation packet exchange tests).

Reference specifications

NDN is not CCNx. NDN Architecture and RFC 8609 define CCNx 1.0 semantics and packet encoding respectively and are not applicable to NDN.

Per-phase summary

The audit covers 126 findings across nine phases (A–I). Phase I findings are architectural misunderstandings that have been corrected in docs and code; they are not listed as open bugs. Witness paths reference scripts under testbed/tests/audit/.

Audit doc line references: phase summaries at lines 694, 1069, 1724, 2320, 2679, 2952, 3234, 3434, 3690.

Verified compliant

Findings in this section have a witness script in testbed/tests/audit/ that exits 0 against the current codebase. RUST-UNIT witnesses run via cargo test; GREP-PROOF witnesses verify absence of a problematic code surface; INTEROP witnesses exchange packets with a reference NDN implementation in the testbed Docker environment.

Wire format (Phase A)

• BLAKE3_DIGEST TLV-TYPE 0x03 surface removed — the type 0x03 name component, zone_root helpers, and blake3digest= URI form are absent from ndn-rs. Witness: testbed/tests/audit/a01_blake3_name_component.sh (GREP-PROOF). (A.01.)

• ParametersSha256DigestComponent structural rules enforced on Interest decode — Interest::decode rejects: AppParameters without a PSDC, PSDC not in last position, multiple PSDCs. Witness: testbed/tests/audit/a02_psdc_structural.sh (RUST-UNIT). (A.02.)

• Unknown critical TLVs rejected at body level — Interest::decode, Data::decode, and MetaInfo::decode abort on unknown critical TLV types (bit 0 set for types ≥ 32, grandfathered-critical for types 0–31). Witness: testbed/tests/audit/a03_unknown_critical_tlv.sh (RUST-UNIT). (A.03.)

• Signed Interest signed region is correct — InterestBuilder::sign / sign_sync compute the signature over the two-range spec region (Name-without-PSDC ‖ AppParameters ‖ InterestSignatureInfo) and set the PSDC after signing. Witness: testbed/tests/audit/a09_signed_interest_verify.sh (RUST-UNIT). (A.09.)

• DataBuilder::build() emits real DigestSha256 — produces a correct 32-byte SHA-256 over the signed region rather than 32 zero bytes. Witness: testbed/tests/audit/a10_databuilder_build_sig.sh (RUST-UNIT). (A.10.)

• TLV field ordering enforced on Interest decode — validate_interest_body_structure rejects Interests whose components arrive out of the spec order (Name, CanBePrefix, MustBeFresh, ForwardingHint, Nonce, InterestLifetime, HopLimit, ApplicationParameters, …). Also closes A.21 — Name::decode rejects a ParametersSha256DigestComponent (type 0x02) anywhere except the last position. Witness: cargo test -p ndn-packet -- a02_psdc (RUST-UNIT). (A.04, A.21.)

• TLV-TYPE restricted to VAR-NUMBER-1/3/5 — TlvReader::read_type rejects the 9-byte form (legal only for TLV-LENGTH per tlv.html) and any value above u32::MAX with TlvError::TypeOutOfRange. Witness: testbed/tests/audit/a05_a18_tlv_strictness.sh (RUST-UNIT). (A.05.)

• NackReason::NotYet declared as ndn-rs-private extension — the registered NackReason codes are 50/100/150; ndn-rs’s internal NotYet=160 signal is now flagged via NackReason::is_registered() and an enum-level doc note so peers and tooling see it as Other(160) on the wire, not as a registered value. (A.11.)

• SignatureValue length validated against SignatureType — validate_data_body_structure rejects fixed-width algorithms whose SignatureValue doesn’t match the spec width (Sha256=32, Hmac=32, Ed25519=64, BLAKE3=32); variable-width algorithms (RSA, ECDSA) pass through. SignatureType::required_signature_value_len is the helper. Witness: testbed/tests/audit/a16_signature_value_length.sh (RUST-UNIT). (A.16.)

• NonNegativeInteger widths restricted to {1,2,4,8} octets — new ndn_packet::decode_nni helper enforces the spec widths (tlv.html). InterestLifetime, FreshnessPeriod, ContentType, SignatureType, SignatureTime, and SignatureSeqNum decoders route through it; 3/5/6/7-octet NNIs and zero-length NNIs are rejected. Witness: testbed/tests/audit/a05_a18_tlv_strictness.sh (RUST-UNIT). (A.18.)

• Name and NameComponent have spec-canonical Ord — TLV-TYPE ascending, then TLV-LENGTH ascending, then lexicographic value; Name compares component-wise so prefix-shorter-first holds. Code unchanged; earlier wiki “remaining gaps” claim was stale. (A.06.)

• Name::decode accepts the root (empty) name — name.html defines the empty Name as valid; the outer Interest::decode and Data::decode still require ≥ 1 component, but KeyLocator and ForwardingHint Name fields can be empty. (A.07.)

• ensure_nonce cites the NFD Developer Guide, not RFC 8569 — the comment in encode/interest.rs::ensure_nonce now refers to NFD Developer Guide §3.4 (outgoing-Interest pipeline) and explicitly flags that RFC 8569 is the CCNx document, not NDN. (A.08.)

• URI round-trip preserves typed components — Name::FromStr now parses the alternates Name::Display emits: sha256digest=<hex>, params-sha256=<hex>, keyword=<text>, and the canonical <type-number>=<value> decimal-prefix form (name.html). Witness: testbed/tests/audit/a19_a20_uri_finalblockid.sh (RUST-UNIT). (A.19.)

• FinalBlockId exposes its wrapped NameComponent — new MetaInfo::final_block_component decodes the inner NameComponent TLV (per data.html) into a typed NameComponent; the raw Bytes field is still available for callers that don’t need the parse. Witness: testbed/tests/audit/a19_a20_uri_finalblockid.sh (RUST-UNIT). (A.20.)

NDNLPv2 (Phase B)

• LpReliability emits TxSequence (0x0348), not Sequence (0x51) — per-LP reliability sequence is carried in TxSequence; Sequence (0x51) is the network-packet fragment identifier only. Witness: testbed/tests/audit/b01_reliability_txsequence.sh (RUST-UNIT). (B.01, B.09.)

• fragment_packet encodes Sequence/FragIndex/FragCount as exactly 8 bytes — NDNLPv2 §6.3 requires all three fragment fields to be 64-bit integers. fragment_packet (the UDP/BLE/Ethernet fragmentation path) now uses .to_be_bytes() rather than variable-length NNI; NFD dropped packets with shorter encodings. Witness: cargo test -p ndn-packet --features std -- fragment (RUST-UNIT). (B.13.)

• No bare-Nack TLV accepted at the top level — Nack::decode rejects the fictional bare-Nack form ndn-rs once tolerated; Nacks must arrive wrapped in an LpPacket per NDNLPv2. Resolved together with A.12. Witness: cargo test -p ndn-packet -- a12_ (RUST-UNIT). (B.08.)

• Bare Interest/Data inside an LpPacket body rejected — NDNLPv2 requires the network packet to be wrapped in LpFragment (0x50). LpPacket::decode previously synthesised a fragment around a bare top-level Interest or Data inside the body; it now returns MalformedPacket, surfacing non-conformant peers. Witness: testbed/tests/audit/b03_b04_lp_strictness.sh (RUST-UNIT). (B.03.)

• PitToken length follows NDNLPv2 “one or more bytes” without an upper bound — the LP decoder only rejects the empty-length case; tokens longer than the previous 32-byte ndn-rs-private ceiling now decode. Witness: testbed/tests/audit/b03_b04_lp_strictness.sh (RUST-UNIT). (B.04.)

• PitToken wire surface scoped as future feature, not spec gap — encode + decode are spec-correct; downstream-side PitToken generation and upstream-side consumption (NDN-DPDK multi-consumer pattern) are not wired in the forwarder. ndn-rs does not advertise NDN-DPDK interop, so this is a documented limitation rather than a deviation. (B.05.)

• LinkService/Transport split fused into the Face trait — the per-face LpReliability state is only allocated by FaceState::new_reliable (UDP today); other faces don’t pay the cost. ndn-rs’s single-trait composition is an architectural choice, not a wire-format deviation. (B.06.)

• NackReason::NotYet in LP path documented as ndn-rs-private — same fix as A.11: external peers decoding the wire see Other(160), not a registered NackReason; NackReason::is_registered() returns false for it. (B.07 via A.11.)

Signatures and certificates (Phase C)

• SignatureType-dispatched verifier — Validator dispatches on SignatureType: Ed25519 (code 3), HmacSha256 (code 4), DigestSha256 (code 0), RsaSha256 (code 1), EcdsaSha256 (code 3), BLAKE3 plain/keyed (codes 6/7). Witness: testbed/tests/audit/c01_rsa_ecdsa_verifiers.sh (RUST-UNIT). (C.01–C.03, C.05.)

• KeyChain::sign_data / sign_interest read SignatureType from signer — the wire SignatureType field matches the signer’s actual algorithm rather than being hard-coded to Ed25519. Witness: testbed/tests/audit/c06_keychain_sigtype_label.sh (RUST-UNIT). (C.06.)

• Certificate names follow Certificate Format v2 — KeyChain::ephemeral and ndn-sec keygen produce /<identity>/KEY/<KeyId>/<IssuerId>/<Version> with <Version> as VersionNameComponent (TLV-TYPE 0x36). Witness: testbed/tests/audit/c07_cert_naming.sh (RUST-UNIT). (C.07.)

• Certificate Content is DER-wrapped SubjectPublicKeyInfo — the 44-byte AlgorithmIdentifier + BIT STRING envelope is present for Ed25519 keys. Witness: testbed/tests/audit/c08_cert_content.sh (RUST-UNIT). (C.08.)

• NDNCERT 0.3 CHALLENGE parameters are TLV-encoded — the CA handler encodes email and pin-code CHALLENGE parameters as TLV, not JSON. Witness: testbed/tests/audit/c13_ndncert_challenge_tlv.sh (RUST-UNIT). (C.13.)

• NDNCERT 0.3 ErrorCode variants match spec values — RunOutOfTries, BadValidationCode, etc. map to the numeric codes from the NDNCERT 0.3 wiki. Witness: testbed/tests/audit/c14_ndncert_error_names.sh (RUST-UNIT). (C.14.)

• LVS schemas with user functions fail safe — TrustSchema::from_lvs_binary sets uses_user_functions() and strict callers can refuse the schema; no silent accept of all packets. Witness: testbed/tests/audit/c16_lvs_user_fn_failsafe.sh (RUST-UNIT). (C.16.)

• KeyChain::validator() defaults to hierarchical schema — no longer wraps accept_all(); the default validator enforces trust chain. Witness: testbed/tests/audit/c17_keychain_default_policy.sh (RUST-UNIT). (C.17.)

• ValidityPeriod uses ISO 8601 UTC encoding — NotBefore/NotAfter are encoded as YYYYMMDDTHHMMSSZ ASCII strings per Certificate Format v2. Witness: testbed/tests/audit/c18_validity_period_iso8601.sh (RUST-UNIT). (C.18.)

• BLAKE3 SignatureType codes 6 and 7 are registry-stable — the codes yoursunny registered (issue #12 closed) are now spec-stable; any remaining “experimental” wording in code/docs has been corrected. (C.04.)

• Signed Interest dispatch end-to-end — KeyChain::sign_interest invokes the A.09-fixed two-range signed-region builder; Validator::validate_interest consumes that wire form in ValidationStage; and ndn-ctl emits command Interests signed with the selected identity rather than unsigned. All three were originally separate findings that resolve together via the A.09 fix. Witness: testbed/tests/audit/{a09_signed_interest_verify.sh,e01_mgmt_unauth.sh,h01_mgmt_signed_region.sh}. (C.10, C.11, C.12.)

Forwarding pipeline (Phase D)

• HopLimit is decremented on forward — the incoming pipeline decrements HopLimit before dispatching; packets with HopLimit = 0 on arrival are dropped. Witness: testbed/tests/audit/d01_hoplimit_decrement.sh (RUST-UNIT + INTEROP). (D.01.)

• /localhop scope enforced on ingress — Interests received on a non-local face with a /localhop prefix are dropped by the incoming pipeline. Witness: testbed/tests/audit/d02_localhop_scope.sh (RUST-UNIT + INTEROP). (D.02.)

• NextHopFaceId LP header consulted by StrategyStage — when present, the LP NextHopFaceId (0x0330) overrides FIB nexthop selection. Witness: testbed/tests/audit/d03_nexthop_faceid.sh (RUST-UNIT). (D.03.)

• PIT keyed on name only; selector-enumeration loop removed — PIT lookup no longer iterates selector combinations; MustBeFresh is not stored in the PIT key. Witness: testbed/tests/audit/d04_pit_aggregation_selectors.sh (RUST-UNIT). (D.04.)

• PitToken echoed on outbound Data/Nack — the in-record LP PitToken is copied onto the outbound packet so NDN-DPDK-style consumers can demultiplex replies. Witness: testbed/tests/audit/d07_pit_token_echo.sh (RUST-UNIT). (D.07.)

• BestRouteStrategy retries on Nack — a Nack from one nexthop triggers a retry to the next-best nexthop rather than propagating immediately. Witness: testbed/tests/audit/d09_bestroute_nack_retry.sh (RUST-UNIT). (D.09.)

• Strategy names include %FD%01 version component — BestRoute, Multicast, and ASF strategy names match the NFD convention. Witness: testbed/tests/audit/d10_strategy_name_version.sh (RUST-UNIT). (D.10.)

• /localhost Data validated rather than blanket-trusted — ValidationStage no longer skips signature verification for Data under /localhost. Witness: testbed/tests/audit/d13_localhost_unvalidated.sh (RUST-UNIT). (D.13.)

• Nonce-collision exposure bounded by HopLimit — the 4-byte nonce field permits at most 2³² distinct values, but the D.01 HopLimit backstop (Interest::decrement_hop_limit in the decode stage drops at 0) bounds genuine-loop traffic regardless of nonce reuse, matching NFD Developer Guide §3.3. Pathological 4-billion-collision scenarios are theoretical only. (D.08.)

• Check-then-act races on PIT and FIB closed — PIT and FIB updates are atomic check-and-insert at the data-structure level (DashMap entry API) rather than a with_entry(...) → insert(...) sequence that could race under parallel pipeline workers. (D.19.)

• PIT aggregation docs cite NFD Developer Guide §4.1, not RFC 8569 — the original RFC 8569 (CCNx 1.0 Semantics) reference on PitToken has been removed by the PIT-key refactor; remaining ensure_nonce / wasm-nonce-counter comments in crates/spec/ndn-packet/src/wire.rs now cite NFD Developer Guide §3.4 and flag the CCNx category error explicitly. (D.05.)

• ForwardingAction::ForwardAfter documented as ndn-rs extension — the delayed-send strategy action is not in the NFD strategy API (which uses afterReceiveInterest + scheduleEvent); ndn-rs’s own strategies are free to use it but ported NFD strategy code should fall back to the callback pattern. No wire-format effect. (D.14.)

• StrategyFilter composition is an opt-in ndn-rs extension — the strategy-choice management surface (Phase E) still enforces one strategy per prefix matching NFD; filters layer on at engine- builder time only. (D.15.)

• /localhost scope enforced upstream of FIB LPM — the decode- stage scope drop runs before StrategyStage::process calls self.fib.lpm(&name), so a /localhost Interest reaching the strategy stage is guaranteed to have arrived on a local face. (D.17.)

• Default-strategy fallback matches NFD best-route — when the per-prefix StrategyTable LPM lookup misses, StrategyStage falls through to BestRouteStrategy, which is NFD’s default StrategyChoice for the root namespace. (D.18.)

Management protocol (Phase E)

• Management command Interests verified before dispatch — ndn-fwd requires valid InterestSignatureInfo; commands without a valid signature are rejected. Default-on trust anchor verification with [security.mgmt] config, dev-mode passthrough available. Three-case live witness run against testbed NFD. Witness: testbed/tests/audit/e01_mgmt_unauth.sh (LIVE testbed). (E.01.)

• Status datasets segmented with version and FinalBlockId — faces/list, fib/list, and other status datasets emit VersionNameComponent suffixed names and FinalBlockId per the NFD segmented-dataset convention. Witness: testbed/tests/interop/fwd_cxx_consumer.sh (INTEROP). (E.04.)

• /localhost/nfd module/verb namespace pruned to NFD’s — the management dispatch no longer exposes ndn-rs-specific modules or verbs to the privilege-gated namespace; the surface matches NFD’s base set so nfdc expectations hold. (Discoverability of the remaining extension surface is tracked separately.) (E.03.)

• Strategy-choice set requires %FD%01 version suffix — the management handler accepts only canonical NFD strategy names (e.g. /localhost/nfd/strategy/best-route/%FD%01); unversioned names are rejected. Rolled into D.10’s strategy-name fix. (E.06.)

Face URIs (Phase F)

• FaceUri scheme correct for IPv4/IPv6 and WebSocket direction — udp4/udp6, tcp4/tcp6, wsclient/wsserver, and wss schemes match the NFD FaceUri conventions that nfdc expects. Witness: testbed/tests/audit/f01_faceuri_schemes.sh (RUST-UNIT). (F.01, F.03, F.06.)

• WebSocket framing: one LpPacket per binary frame — net/websocket.rs emits one LpPacket per tungstenite binary message; text messages are ignored. Matches NDNts and @ndn-cxx/websocket-face. (F.05.)

• SHM SPSC face documented as ndn-rs-only same-host transport — feature-gated behind spsc-shm. The only spec’d local face is unix://; SHM SPSC is a proprietary ndn-rs extension. (F.07.)

• Serial / COBS face documented as proprietary — COBS framing follows the esp8266ndn convention but no NDN standard exists for serial transport. serial:// FaceUri is ndn-rs-invented. (F.08.)

• BLE face matches NDNts/esp8266ndn — GATT service / characteristic UUIDs match reference implementations; framing uses NDNLPv2 fragmentation with no private header. Positive. (F.09, B.11.)

• WfbFace is an explicit not-implemented stub — declared- experimental and listed on the v0.2.0 deferred list in docs/unimplemented.md; returns FaceError::Closed as the signal. No spec claim is made. (F.11.)

• InProcHandle/InProcFace mirrors NFD’s InternalFace — connects the management dispatcher to the engine without a network round-trip. Reachable via engine.faces() directly, so the formatter doesn’t emit internal:// — naming drift, not a capability gap. (F.12.)

Routing and sync (Phase G)

• SVS state vector keyed on canonical Name — SvsNode.vector uses NameComponent-aware canonical ordering rather than stringified URI, preventing key mismatches with non-ASCII or typed name components. Witness: testbed/tests/audit/g02_svs_typed_components.sh (RUST-UNIT). (G.02.)

• PSync IBF uses MurmurHash3 — the IBF hash family matches the C++ PSync reference implementation. Witness: testbed/tests/audit/g03_psync_interop.sh (RUST-UNIT). (G.03.)

• NLSR LSA wire format matches C++ NLSR — AdjLsa, NameLsa, and CoordinateLsa TLV encodings round-trip against golden byte vectors from NLSR/tests/lsa/. ExpirationTime uses YYYY-MM-DD HH:MM:SS UTC to match ndn-cxx’s readString format. Witness: testbed/tests/audit/g04_nlsr_lsa_roundtrip.sh (RUST-UNIT). (G.04 phase 1.)

• NLSR full interop with C++ NLSR — ndn-rs (ndn-fwd + NlsrProtocol) and C++ NLSR converge routing tables within 90 s in the two-node testbed Docker environment. ndn-fwd-nlsr learns /test/r1/data from nlsr-cxx; nlsr-cxx learns /test/r2/data from ndn-fwd-nlsr. Fixes: PSync PSyncContent (0x80) wrap/unwrap, CanBePrefix on sync Interests, private Hello UDP face (no engine interference), CallbackFace at /<own_router>/nlsr/INFO for incoming Hello Interests, reduced hello/adj-lsa-build/routing-calc intervals (5/2/5 s). Witness: testbed/tests/audit/g04_nlsr_interop.sh (INTEROP — exits 0 as of 2026-05-08). (G.04.)

• prefix-announce NDNLPv2 header threaded through the forward path — Discovery’s PrefixAnnouncement (LP type 0x0350) is consumed by the forwarder consumer at the dispatcher rather than being decoded and dropped. Architectural fix paired with the D.14 forwarding-information enricher. (G.09.)

• SVS wire format matches ndn-svs C++ — ndn-sync uses TLV_STATE_VECTOR = 0xC9, TLV_SV_ENTRY = 0xCA, TLV_SV_SEQ_NO = 0xCC, TLV_MAPPING_DATA = 0xCD, TLV_MAPPING_ENTRY = 0xCE, matching named-data/ndn-svs’s tlv.hpp. SyncInterests follow the /<group-prefix>/svs ApplicationParameters convention. (G.01.)

• DvrProtocol scoped as proprietary ndn-rs routing — distance- vector routing over NDN with no published spec or cross- implementation peer. For inter-implementation routing use NLSR (G.04); DVR is available for ndn-rs-only topologies. (G.05.)

• service_discovery (BROWSE/ANNOUNCE/WITHDRAW) is ndn-rs-internal — no published NDN standard exists at this layer. The module is scoped for ndn-rs-internal interop only. (G.07.)

• ChronoSync absence is a deliberate scope choice — the historical first NDN sync protocol is unimplemented; modern deployments use SVS, which ndn-rs ships with spec-correct wire format and canonical-Name keying. (G.08.)

Management tool (Phase H)

• ndn-ctl command Interests are key-backed signed — MgmtClient accepts a Signer and ndn-ctl --identity / --pib flags select a PIB key. Commands carry InterestSignatureInfo + SigNonce + SigTime in the v0.3 signed-Interest form. Witness: testbed/tests/audit/h01_mgmt_signed_region.sh (LIVE). (H.01.)

• ndn-sec keygen produces spec-compliant cert names and SPKI keys — cert names follow the /<identity>/KEY/<KeyId>/<IssuerId>/<Version> convention; the public key field is a DER-wrapped SubjectPublicKeyInfo. (H.05.)

• ndn-app consumer signed Interests use correct signed region — KeyChain::sign_interest calls the A.09-fixed build_signed_interest_parts path; the Ed25519 signature verifies against the two-range spec region. Witness: testbed/tests/audit/h10_app_signed_interest.sh (RUST-UNIT). (H.10.)

• did-ndn-driver rests only on spec-compliant primitives — the W3C DID resolver over NDN uses ndn_did::UniversalResolver rather than the removed BLAKE3-name-component surface (A.01) and inherits the A.09 signed-Interest fix. (H.08.)

• encode_data_digest_sha256 accurately names the legacy helper — the misleading encode_data_unsigned name (output is in fact DigestSha256-signed Data) now has an accurately-named replacement; the old name is retained as a #[doc(hidden)] alias so existing call sites in ndn-engine, ndn-store, ndn-fwd, and the test harnesses don’t churn. (H.04.)

• ndn-fwd UDP listener is equivalent to NFD’s UDP channel — the listener owns the socket and creates send-only UdpFace references per peer, pushing received bytes via inject_packet. Valid implementation of the NFD channel concept; positive. (H.06.)

• ndn-fwd TCP listener inherits the F.04 LP-wrap fix — non- local egress is wrapped in LpPacket so per-hop headers have a frame to live in. Witness: testbed/tests/audit/f04_lp_wrap_nonlocal_egress.sh. (H.07.)

Known non-compliant

MAJOR — deviations a reference implementation would reject or misinterpret

A.12 RESOLVED 2026-04 (witness 2026-05-13 sweep) — Nack::decode rejects any outer TLV that is not LpPacket (0x64) and only accepts the NDNLPv2-wrapped Nack form. The legacy bare-Nack test helper has been removed. Witness: testbed/tests/audit/a12_nack_lp_only.sh.

A.15 RESOLVED 2026-05-13 — Data::decode and Interest::decode now call SignatureInfo::decode eagerly when they see the signature TLV. KeyLocator-by-SignatureType rule violations (DigestSha256 with a KeyLocator, Ed25519 without one, etc.) are now surfaced as KeyLocatorRule errors at outer-packet decode time instead of being silently swallowed by the lazy sig_info() accessor. Witness: testbed/tests/audit/a15_keylocator_rules.sh (extended with a15_data_decode_rejects_* cases).

B.02 RESOLVED 2026-05-13 — LpPacket::decode enforces the critical-bit rule (is_critical_tlv_type) on unknown LP header TLVs instead of silently skipping them. Unknown ODD types (critical) reject with MalformedPacket; unknown EVEN types (non-critical) are tolerated for forward compat. Witness: testbed/tests/audit/b02_lp_unknown_critical.sh.

D.12 RESOLVED 2026-05-13 — ValidationStage::process no longer opportunistically sets ctx.verified = true when the engine was built without a Validator. The fix is fail-secure: validator = None returns Action::Satisfy(ctx) without touching verified, so CsInsertStage (stages/cs.rs:50) skips admission. Local-face Data is still cached because dispatcher/pipeline.rs:320 short-circuits verified = true for FaceScope::Local Data before this stage runs. Witness: testbed/tests/audit/d12_cs_unverified_admission.sh.

G.06 ARCHIVED 2026-05-13 — SWIM-over-NDN is now scoped as a non-testbed ndn-rs extension rather than an AutoConfig substitute. See the BLOCKED-BY-INTEROP entry below for the standards-track gap. Open work on NDN AutoConfig itself is tracked separately and not a blocker for testbed interop today.

MINOR — strictness gaps and edge cases

A.17 RESOLVED 2026-05-12 — BLAKE3 SignatureType codes 6 and 7 are now registered on the NDN TLV SignatureType registry (yoursunny issue #12 closed). Any remaining documentation describing them as “experimental and unregistered” should be updated; the codes are spec-stable.

A.13 RESOLVED 2026-05-12 — Interest::decode now rejects any Nonce TLV whose length is not exactly 4 bytes (NDN Packet Format v0.3 §3.2). Witness: testbed/tests/audit/a13_nonce_length_rejected.sh.

A.14 RESOLVED 2026-05-12 — ContentType::Manifest (4) and ContentType::PrefixAnn (5) are now typed enum variants. Witness: testbed/tests/audit/a14_content_type_typed_variants.sh.

B.10 RESOLVED 2026-05-13 — ReassemblyBuffer is now capped at MAX_PENDING_PACKETS = 1024 concurrent partial groups. Insertions over the cap run a lazy purge_expired first and then evict the oldest entry, so a peer flooding never-completed first-fragments cannot inflate buffer memory between external ticks. Witness: testbed/tests/audit/b10_reassembly_cap.sh.

D.06 RESOLVED 2026-05-13 — StrategyStage now records each outbound (face_id, nonce) pair in the PIT entry’s out_records and suppresses any re-send to the same face with the same nonce (crates/spec/ndn-engine/src/stages/strategy.rs, Forward branch). If every chosen out-face is a duplicate, the Interest is dropped with DropReason::Suppressed. Mirrors NFD Developer Guide §3.4. Witness: testbed/tests/audit/d06_pit_out_record_dedup.sh.

D.11 RESOLVED 2026-05-13 (positive finding) — Re-verified against the audit doc: both LRU and Fjall CS backends drop stale entries when MustBeFresh is set (crates/spec/ndn-store/src/{lru_cs.rs:83,fjall_cs.rs:267}), and CsLookupStage returns Action::Continue on every miss (crates/spec/ndn-engine/src/stages/cs.rs:33) so the Interest falls through to PIT + strategy + upstream forwarding. The earlier wiki summary was incorrect.

E.02 RESOLVED 2026-05-13 — run_ndn_mgmt_handler binds source_face = Some(handle.face_id()) directly from the InProcHandle it is reading from. Previously the handler called engine.source_face_id(&interest), which walked the PIT and returned the first in-record’s face_id for a matching name hash; two commands from different faces with identical name hashes inside the 4-second PIT lifetime could resolve to each other’s face_id, an authorization boundary bug. InProcHandle now exposes the paired InProcFace.id via face_id(). Witness: testbed/tests/audit/e02_source_face_from_handle.sh.

E.07 RESOLVED 2026-05-13 — mgmt::faces_* dispatches verb::UPDATE to a faces_update handler that honours NFD Flags+Mask semantics: each bit set in Mask selects whether the corresponding Flags bit replaces the current per-face bitmap (FaceState.flags), and the 200 ControlResponse echoes the new Flags value. Without Mask, Flags is ignored. Parameters ndn-rs does not yet wire up at runtime (FacePersistency, Mtu) return 409 CONFLICT. Management privilege gate matches faces/destroy. Witness: testbed/tests/audit/e07_faces_update_verb.sh.

E.08 RESOLVED 2026-05-13 — FaceStatus emits Flags (0x6c), NSatisfiedInterests (0x99), and NUnsatisfiedInterests (0x9a) per ndn-cxx tlv-nfd.hpp with live per-face values. Each FaceState carries in_satisfied_interests and in_unsatisfied_interests AtomicU64 counters: the satisfied counter is bumped in dispatcher/outbound.rs::satisfy for every downstream face the matched Data is sent to, and the unsatisfied counter is bumped in run_expiry_task for every in-face on a timed-out PIT entry. FaceState.flags carries the NFD FaceFlagBit bitmap: bit 0 (LocalFieldsEnabled) auto-set for local-scope faces, bit 1 (LpReliabilityEnabled) auto-set when face-net reliability is wired up. Witness: testbed/tests/audit/e08_face_status_flags.sh.

F.10 RESOLVED 2026-05-13 (positive) — Re-verified against the audit doc: the wire-level pieces are spec-correct on every backend (l2/{ether,ether_macos,ether_windows,af_packet,ndrv,pcap_face, multicast_ether}.rs) — EtherType 0x8624 and NDN multicast MAC 01:00:5e:00:17:aa, matching NFD. The original audit text flagged ~46 FIXMEs around AF_PACKET mmap tuning / socket lifecycle as implementation quality (not a spec gap); they remain tracked as engineering work in docs/notes/.

F.04 RESOLVED 2026-05-13 — Egress on non-local faces is wrapped in an LpPacket so per-hop NDNLPv2 headers (CongestionMark, NextHopFaceId, IncomingFaceId, PitToken on Data) have a frame to live in, matching NFD’s GenericLinkService behaviour on network faces. Local-scope faces keep bare TLV. Witness: testbed/tests/audit/f04_lp_wrap_nonlocal_egress.sh.

F.02 RESOLVED 2026-05-12 — MulticastUdpFace::ndn_default now binds the multicast group on UDP/56363, matching NFD’s DEFAULT_MULTICAST_PORT (daemon/face/multicast-udp-factory.cpp). The new NDN_MULTICAST_PORT constant disambiguates from NDN_PORT (unicast). Witness: testbed/tests/audit/f02_multicast_port_56363.sh.

H.02 RESOLVED 2026-05-13 — ndn-ping server now registers <prefix>/ping (matching ndn-tools ping-server.cpp:43) and the CLI default --prefix is /ndn, so the default registered name is /ndn/ping per the ndn-cxx ndnping convention. Witness: testbed/tests/audit/h02_ping_prefix_ndnping_compat.sh.

H.03 DOCUMENTED 2026-05-13 — ndn-iperf is scoped as a proprietary ndn-rs-only tool: no ndn-cxx ndniperf equivalent exists and the segment naming / --sign-mode parameter are not standardised. Crate-level doc on binaries/tooling/ndn-tools/src/iperf.rs declares this; the tool is interop only between ndn-iperf peers.

DOCS — documentation was incorrect or stale

H.09 RESOLVED 2026-05-13 — ndn-bench does not actually emit signed Data; on inspection it measures InProcHandle ↔ InProcFace channel round-trip overhead with a fixed 3-byte dummy payload and never reaches the signing or CS paths. The crate-level doc on binaries/tooling/ndn-bench/src/main.rs declares this scope explicitly (no end-to-end forwarding, no signing throughput) so readers do not misinterpret the numbers. Use ndn-iperf against a wired-up ForwarderEngine for real benchmarks.

BLOCKED-BY-INTEROP

These findings have code-level implementations. This section tracks which ones have a passing live-peer witness against a reference NDN implementation versus which still rely on architecture-only witnesses.

• NDNCERT 0.3 CHALLENGE round-trip against ndncert-ca-server (C.13 — WITNESSED 2026-05-13). testbed/tests/audit/c13_ndncert_live_interop.sh drives the full NEW → CHALLENGE pin → cert-issue flow against the upstream named-data/ndncert CA via the nfd-ndncert + ndncert-ca containers. Issued cert decodes through ndn-rs’s Certificate v2 decoder; issuer chains back to /test/ndncert/CA. Live pcap transcript: testbed/tests/audit/transcripts/c13_ndncert_live_interop_after.pcap.

• PSync dataset sync with a C++ PSync peer (G.03 — architecture WITNESSED; live interop PENDING). testbed/tests/audit/g03_psync_iblt_roundtrip.sh and g03_psync_reconcile.sh exercise the wire-format primitives (MurmurHash3 IBF, BCH-shaped reconciliation) entirely in Rust. A bidirectional live sync against named-data/PSync would discharge the remaining live marker but needs (a) a Rust ndn-psync-consumer CLI in ndn-tools and (b) a cmake-built C++ full-producer example on the test host.

• Live management notification streams (E.05 — architecture WITNESSED; live interop PENDING). testbed/tests/audit/e05_notification_streams.sh exits 0 today against the NotificationStream publisher unit tests in ndn-config. Live nfdc events subscriber interop is blocked on the testclient image carrying the ndn-cxx nfdc binary.

• nfdc trust-schema validation of mgmt responses signed by ndn-rs (N.12 — architecture WITNESSED; live interop PENDING). testbed/tests/audit/n12_mgmt_response_signing.sh exits 0 today against the ndn-fwd mgmt-response-signer unit tests (SignatureEd25519 + KeyLocator). Live nfdc trust-schema enforcement is blocked on the testclient image carrying nfdc plus a configured trust anchor.

G.06 (SWIM-over-NDN vs NDN AutoConfig) is no longer in this section — it is archived as an ndn-rs extension rather than a testbed-blocked interop case.

How to report a spec compliance issue

File it against github.com/Quarmire/ndn-rs/issues with:

• The NDN spec clause you believe is violated (link + section).
• A minimal wire capture or source reference showing ndn-rs’s behaviour.
• Your expected behaviour.

Per the project’s witness-first workflow: new issues are resolved by adding a witness script to testbed/tests/audit/<id>_<slug>.sh that exits 1 against the broken code and 0 after the fix, with before/after transcripts in testbed/tests/audit/transcripts/.

Related open issues: #3, #7, #9, #12, #13, #17, #18, #20, #21.

Full per-finding detail: docs/notes/spec-compliance-audit-2026-04-20.md. Witness harness: testbed/tests/audit/ (per-finding) and testbed/tests/interop/ (cross-impl).