Talon
f3ac779bf4
Media died silently whenever a client's source address changed. The relay bound a peer's endpoint once and refused to move it, and the client stopped offering its binding token after the first bind, so a Wi-Fi/cellular handover stranded the session in both directions. Add an authenticated Rebind media frame: the binding token travels in the clear for peer lookup only, and the AEAD tag over header and token plus the peer's existing replay window are what authorize the move, so a captured rebind cannot be replayed to redirect someone else's downlink. The client rebuilds its UDP socket instead of retrying on one still pinned to a vanished interface. Nothing judged the control connection live: pings were sent and pongs ignored, so a blackholed TCP path went unnoticed for minutes while the UI showed a live session. Treat any server traffic as liveness and fail the connection when it stops, which drives the existing reconnect. The receive jitter buffer had lost its depth floor, so a channel without FEC or DRED played out with no buffer at all and ordinary reordering became concealment. Restore a one-frame floor, observe every arrival rather than only accepted ones — a shallow buffer was rejecting the late arrivals that should have deepened it — and allow playout to hold a frame so depth can follow a degrading link. A stalled consumer now sheds the oldest queued packet instead of refusing the live talkspurt. Add a deterministic network-impairment simulation covering bursty loss, jitter, reordering, duplication, outages and a stalled consumer, a handover test against a real relay, a replay test for the rebind path, and a blackholed control connection driven through a freezable TCP proxy.
VoiceCat documentation
VoiceCat is a self-hosted channel-based voice and text system. Control traffic uses TLS 1.3; media uses authenticated encrypted UDP derived from the TLS session. There is no plaintext mode or central service.
Current references:
- architecture.md — components, ownership, concurrency, and native boundary.
- api-dotnet.md — managed API and ownership contracts.
- building.md — development, platform builds, tests, and publishing.
- deployment.md — server packaging and operations.
- ios-deploy.md — physical-device iOS build and deployment.
- tech-stack.md — supported dependencies and licensing.
- broadcast-ring-format.md — frozen extension/host ring ABI.
proto/voicecat.proto is the control-plane wire contract. Managed tests are the executable
behavior contract. Keep prose current with those sources rather than documenting historical
implementations.
Durable rules:
- Encryption is mandatory.
- GPL and LGPL dependencies are forbidden.
- Real-time audio callbacks never allocate, lock, block, or perform I/O.
- The server relays encoded media; it does not mix or transcode it.
- Wire, database, and shared-ring changes are explicitly versioned.