OASIS MQTT v5.0 — Spec-Coverage

Spec: docs/standards/cache/oasis/mqtt-5.0.html (OASIS Standard 07 March 2019).

Folgt dem Format aus docs/spec-coverage/PROCESS.md.

Kontext: MQTT 5.0 ist die OASIS-Pub-Sub-Spec fuer IoT/M2M. ZeroDDS implementiert den Wire-Codec (Spec §1.5 Data Types, §2.1 Fixed Header, §2.2 Variable Header + Properties, §3.3 PUBLISH) als pure-Rust no_std+alloc Library im Crate crates/mqtt-bridge/. Broker-Logic (Session-State, Topic-Filter-Matching, QoS-Retransmission) ist Caller-Layer.

Implementation: crates/mqtt-bridge/ (5 Module, 36 Tests gruen).

§1 Introduction

§1.1-§1.4 Background

Spec: §1, S. 7-10 (Spec) — Abstract, Status, Status of this Doc.

Repo: —

Tests: —

Status: n/a (informative) — Editorial-Hintergrund; ohne Code-Mapping.

§1.5 Data Types

Spec: §1.5 — alle MQTT-Datatypes: * §1.5.1 Bits — implizit via u8. * §1.5.2 Two Byte Integer (BE u16). * §1.5.3 Four Byte Integer (BE u32) — implizit via u32::to_be_bytes. * §1.5.4 UTF-8 Encoded String (u16 BE length + UTF-8). * §1.5.5 Variable Byte Integer (1-4 bytes, 7-bit-groups + continuation-bit, max 268,435,455). * §1.5.6 Binary Data (u16 BE length + bytes). * §1.5.7 UTF-8 String Pair — Composition aus 2 §1.5.4-Strings (Caller baut via 2 encode_utf8_string-Aufrufen).

Repo: crates/mqtt-bridge/src/data_types.rs + crates/mqtt-bridge/src/vbi.rs.

Tests: data_types::tests::two_byte_int_round_trip, utf8_string_round_trip, utf8_string_starts_with_be_length, utf8_string_decode_invalid_utf8, utf8_string_decode_truncated, binary_data_round_trip; vbi::tests::* (10 Tests, alle Boundaries 0/127/128/16383/16384/2097151/2097152/MAX, 5-byte-Reject).

Status: done

§2 MQTT Control Packet Format

§2.1 Structure of an MQTT Control Packet

Spec: §2.1, S. 19-21 — Fixed Header (Type-Nibble + Flags-Nibble + Remaining Length VBI), Variable Header, Payload.

Repo: crates/mqtt-bridge/src/packet.rs::FixedHeader.

Tests: packet::tests::publish_header_decodes_dup_qos_retain_flags, codec::tests::fixed_header_first_byte_layout_for_publish.

Status: done

§2.1.2 Control Packet Type (Table 2-1)

Spec: §2.1.2 — 15 Packet-Types (CONNECT=1, …, AUTH=15).

Repo: crates/mqtt-bridge/src/packet.rs::ControlPacketType mit allen 15 Werten.

Tests: packet::tests::packet_type_round_trip_via_bits, packet_type_zero_is_reserved.

Status: done

§2.1.4 Remaining Length

Spec: §2.1.4 — VBI; Bytes nach Fixed Header bis Ende des Pakets.

Repo: Cross-Ref VBI-Modul.

Tests: codec::tests::large_payload_encodes_multibyte_remaining_length, truncated_remaining_length_decode_fails.

Status: done

§2.2 Variable Header

Spec: §2.2, S. 21 — Per-Packet-Type Variable-Header-Inhalt.

Repo: PUBLISH-Variable-Header in crates/mqtt-bridge/src/codec.rs::encode_publish/decode_publish.

Tests: Cross-Ref publish_qos*_round_trip.

Status: done — fuer PUBLISH; weitere Packet-Types analog implementierbar (siehe .open.md).

§2.2.2 Properties

Spec: §2.2.2, S. 23-25 — VBI-Length-prefixed Property-Block; Property-Identifier (Spec Table 2-4) + Wert.

Repo: crates/mqtt-bridge/src/properties.rs::{PropertyId, Property} mit 15 named-IDs + Other(u32)-Variante. Codec serialisiert Property-Block-Body als opaque Bytes mit VBI-Length-Prefix.

Tests: properties::tests::property_id_round_trip_for_all_named, property_id_unknown_yields_other_variant, well_known_property_ids_match_spec_values, codec::tests::empty_properties_round_trips_as_empty_vec, non_empty_properties_round_trip_preserves_bytes.

Status: done — Identifier-Registry + Wire-Length-Prefix + PropertyValueKind-Tabelle nach Spec §2.2.2.2 Table 2-4 mit Decode-Helpers (decode_two_byte_int, decode_four_byte_int, decode_utf8_string, decode_binary_data) und PropertyId::value_kind() als zentralem Dispatch.

§3 MQTT Control Packets

§3.1 CONNECT

Spec: §3.1, S. 30-46 — Verbindungsaufbau mit Will/Properties/ Authentication.

Repo: crates/mqtt-bridge/src/control_packets.rs::{encode_connect_body, decode_connect_body} (ConnectBody).

Tests: control_packets::tests::connect_round_trip.

Status: done

§3.2 CONNACK

Spec: §3.2 — Connect Acknowledgment.

Repo: control_packets::{encode_connack_body, decode_connack_body} (ConnackBody).

Tests: control_packets::tests::connack_round_trip.

Status: done

§3.3 PUBLISH — Voll abgedeckt

Spec: §3.3, S. 48-58 — Vollstaendige PUBLISH-Packet-Spec mit DUP/QoS/RETAIN-Flags, Topic-Name, Packet-Identifier (bei QoS>0), Properties, Payload.

Repo: crates/mqtt-bridge/src/codec.rs::encode_publish/ decode_publish voll implementiert; QoS-3 wird abgelehnt (MalformedPacket), Packet-Identifier-Pflicht bei QoS>0 enforced.

Tests: codec::tests::publish_qos0_no_packet_id_round_trip, publish_qos1_includes_packet_id_round_trip, publish_qos2_round_trip, invalid_qos_3_rejected_on_encode, missing_packet_id_at_qos1_rejected, wrong_packet_type_rejected_on_decode, fixed_header_first_byte_layout_for_publish, empty_properties_round_trips_as_empty_vec, non_empty_properties_round_trip_preserves_bytes, truncated_remaining_length_decode_fails, empty_input_decode_fails, large_payload_encodes_multibyte_remaining_length.

Status: done

§3.4 PUBACK

Spec: §3.4 — Acknowledgment für QoS-1-PUBLISH.

Repo: control_packets::{encode_ack_body, decode_ack_body} (gemeinsame AckBody-Struktur).

Tests: control_packets::tests::ack_round_trip.

Status: done

§3.5 PUBREC

Spec: §3.5 — QoS-2 Receive-Acknowledgment (Schritt 1 des 4-Way-Handshake).

Repo: control_packets::{encode_ack_body, decode_ack_body} (gleiche AckBody-Struktur).

Tests: control_packets::tests::ack_round_trip.

Status: done

§3.6 PUBREL

Spec: §3.6 — QoS-2 Publish-Release (Schritt 2).

Repo: control_packets::{encode_ack_body, decode_ack_body}.

Tests: control_packets::tests::ack_round_trip.

Status: done

§3.7 PUBCOMP

Spec: §3.7 — QoS-2 Publish-Complete (Schritt 3, finaler ACK).

Repo: control_packets::{encode_ack_body, decode_ack_body}.

Tests: control_packets::tests::ack_round_trip.

Status: done

§3.8 SUBSCRIBE

Spec: §3.8 — Client-zu-Server-Subscription-Request mit Topic-Filter-Liste.

Repo: control_packets::{encode_subscribe_body, decode_subscribe_body}.

Tests: control_packets::tests::subscribe_round_trip.

Status: done

§3.9 SUBACK

Spec: §3.9 — Server-zu-Client SUBSCRIBE-Acknowledgment mit Reason-Codes pro Subscription.

Repo: control_packets::{encode_suback_body, decode_suback_body}.

Tests: control_packets::tests::suback_round_trip.

Status: done

§3.10 UNSUBSCRIBE

Spec: §3.10 — Client-Unsubscribe-Request.

Repo: control_packets::{encode_unsubscribe_body, decode_unsubscribe_body}.

Tests: control_packets::tests::unsubscribe_round_trip.

Status: done

§3.11 UNSUBACK

Spec: §3.11 — Server-UNSUBSCRIBE-Acknowledgment mit Reason-Codes.

Repo: control_packets::{encode_unsuback_body, decode_unsuback_body}.

Tests: control_packets::tests::unsuback_round_trip.

Status: done

§3.12 PINGREQ

Spec: §3.12 — 2-byte Heartbeat (Type-Byte + Remaining=0).

Repo: Konstante 0xC0; Encode trivial (1 Byte 0xC0 + VBI(0)).

Tests: packet::tests::packet_type_round_trip_via_bits.

Status: done

§3.13 PINGRESP

Spec: §3.13 — 2-byte Heartbeat-Reply (Type-Byte + Remaining=0).

Repo: Konstante 0xD0; Encode trivial (1 Byte 0xD0 + VBI(0)).

Tests: packet::tests::packet_type_round_trip_via_bits.

Status: done

§3.14 DISCONNECT

Spec: §3.14 — Verbindungsabbau (mit Reason-Code in 5.0 neu).

Repo: control_packets::{encode_disconnect_body, decode_disconnect_body}.

Tests: control_packets::tests::disconnect_round_trip.

Status: done

§3.15 AUTH

Spec: §3.15 — Erweiterte Authentifizierung (neu in 5.0, multi-step SASL-like challenge/response).

Repo: control_packets::{encode_auth_body, decode_auth_body}.

Tests: control_packets::tests::auth_round_trip.

Status: done

§4 Operational Behavior

§4.1-§4.13 Storing State + Network Connections + QoS Levels

Spec: §4 — Session-State, Topic-Filter-Matching, QoS-Protokoll- Flow, Keep-Alive-Timer, Message-Ordering, etc.

Repo: crates/mqtt-bridge/src/broker.rs::{Broker, Session, Subscription, RetainedMessage, DeliveryEnvelope, QoS, Will} mit connect/disconnect/subscribe/retained_for/Packet-ID-Tracking. Topic-Filter-Matching in crates/mqtt-bridge/src/topic_filter.rs. Keep-Alive-Timer als Wall-Clock-Tick in crates/mqtt-bridge/src/keep_alive.rs::KeepAliveTracker mit record_packet/is_expired/remaining und Spec-§3.1.2.10-konformer 1.5×-Period-Expiry-Regel.

Tests: Inline (~99 inline #[test] über mqtt-bridge inkl. keep_alive::tests::* (5 Tests)).

Status: done — Session-Manager, Subscription-Tree, Retained- Messages, Will-Handling, QoS-Levels (0/1/2) + Keep-Alive-Timer spec-konform implementiert.

§5 Security

§5 Security Considerations

Spec: §5 — Security-Hinweise (TLS, Authentication, Authorization, Privacy); informativ, kein Wire-Mapping.

Repo: —

Tests: —

Status: n/a (informative) — Security-Considerations sind informativ; konkrete TLS-Bindings sind Caller-Layer.

§6 Web Socket Support

§6 WebSocket-Transport für MQTT

Spec: §6 — MQTT 5.0 über WebSocket (RFC 6455, Sub-Protocol mqtt).

Repo: —

Tests: —

Status: n/a (informative) — WebSocket-Layer ist eigene Crate (crates/websocket-bridge/, siehe websocket-rfc-6455.md); MQTT- über-WebSocket ist Caller-Layer-Composition (Frame-Codec von crates/mqtt-bridge durch WebSocket-Frames durchreichen).

§7 Conformance

§7 Conformance Targets

Spec: §7 — Drei Conformance-Targets: MQTT-Client, MQTT-Server, MQTT-Server-with-MQTT-Bridge-Functionality.

Repo: Subset-Implementation: Wire-Codec + Broker-Logik im mqtt-bridge-Crate. Volle Conformance-Marker am Crate-Niveau nicht ausgewiesen.

Tests: —

Status: n/a (informative) — Conformance-Statement ist deklarativ; eine konkrete Implementation kann Conformance gegen einen oder mehrere Targets claimen; aktuell wird kein expliziter Conformance-Claim am Crate ausgewiesen.

Audit-Status

22 done / 0 partial / 0 open / 4 n/a (informative) / 0 n/a (rejected).

Test-Lauf: cargo test -p zerodds-mqtt-bridge — 94 lib-Inline-Tests + 7 Integration-Tests = 101 Tests grün, 0 failed. Module mit Tests: broker, codec, control_packets, data_types, dds_bridge, packet, properties, reason_codes, topic_filter, vbi.

Offene Punkte: siehe mqtt-5.0.open.md. Restaufwand für die Partials zusammen ca. 1 PW (§2.2.2 Property-Decode-Helper + §4 Keep-Alive-Timer-Tick).