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Part A — source-route origination policy: - Gate route application (BLESourceRouteOriginationPolicy): only packets we author, directed at a single peer, with TTL headroom, whose recipient is not directly connected. Relays no longer attach routes to (and re-sign) packets they merely forward. - Version-gate paths: MeshTopologyTracker records the highest protocol version observed per peer; BFS routes require every intermediate hop and the recipient to be v2-observed, capped at 4 intermediate hops. - Degrade on failure: BLESourceRouteFailureCache marks a routed send that sees no inbound traffic from the recipient within 10s as failed and floods for 60s before retrying routes. Part B — REQUEST_SYNC fragmentIdFilter (TLV 0x06): - Requester: BLEFragmentAssemblyBuffer reports stalled broadcast reassemblies (no new fragment for 5s, retried at most every 10s); the maintenance pass sends a types=fragment REQUEST_SYNC naming the stalled 8-byte fragment stream IDs to each connected peer. - Responder: GossipSyncManager restricts the fragment diff to exactly the named streams, bypassing the since-cursor while the GCS filter still excludes pieces the requester holds; RSR/TTL-0/rate-limit semantics unchanged and REQUEST_SYNC stays link-local. - Bounds: at most 60 IDs per request (60*17-1 = 1019 bytes <= the 1024-byte decoder cap); oversized 0x06 values are ignored, not fatal. Docs: SOURCE_ROUTING.md gains the iOS origination policy (§8); REQUEST_SYNC_MANAGER.md documents 0x05/0x06 as implemented. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Test Harness Guide
This test suite uses an in-memory networking harness to make end-to-end and integration tests deterministic, fast, and race-free without touching production code.
In-Memory Bus
- File:
bitchatTests/Mocks/MockBLEService.swift - Registry/Adjacency: Global
registrymapspeerIDto aMockBLEServiceinstance;adjacencyrecords simulated links between peers. - Setup: Call
MockBLEService.resetTestBus()insetUp()to clear state between tests. - Topology: Use
simulateConnectedPeer(_:)andsimulateDisconnectedPeer(_:)to add/remove links.connectFullMesh()helpers in tests build larger topologies. - Handlers: Tests can observe data via
messageDeliveryHandler(decodedBitchatMessage) andpacketDeliveryHandler(rawBitchatPacket). - De‑duplication: A thread-safe
seenMessageIDsprevents duplicate deliveries during flooding/relays.
Broadcast Flooding
- Flag:
MockBLEService.autoFloodEnabled - Intent: When
true, public broadcasts propagate across the entire connected component (ignores TTL for reach) while still de‑duping to prevent loops. - Usage: Enabled in Integration tests (
setUp) to simulate large-network broadcast; disabled in E2E tests to keep routing explicit and verify TTL behavior (seePublicChatE2ETests.testZeroTTLNotRelayed).
Rehandshake Flow (Noise)
- Why: The legacy NACK recovery path was removed; recovery now relies on Noise session rehandshake after decrypt failure or desync.
- Manager:
NoiseSessionManagermanages per-peer sessions. - Pattern: On decrypt failure, proactively clear the local session and re-initiate a handshake. The peer accepts and replaces their session.
- Test:
IntegrationTests.testRehandshakeAfterDecryptionFailure- Corrupts ciphertext to induce a decrypt error.
- Calls
removeSession(for:)on the initiator’s manager beforeinitiateHandshake(with:)to avoidalreadyEstablished. - Verifies encrypt/decrypt succeeds post-rehandshake.
Tips
- Determinism: Add small async delays only where handler installation/topology changes could race the first send.
- Scoping: Keep
autoFloodEnabledtoggled only within Integration tests; always reset intearDown()to avoid cross-test contamination. - Direct vs Relay: Private messages target a specific peer when adjacent; otherwise they are surfaced to neighbors for relay and, if known, also delivered to the target.
Quick Start
- Create nodes and connect them:
let svc = MockBLEService(); svc.myPeerID = "PEER1"svc.simulateConnectedPeer("PEER2")
- Observe messages:
svc.messageDeliveryHandler = { msg in /* asserts */ }
- Enable broadcast flooding for Integration suites only:
MockBLEService.autoFloodEnabled = true