Module bgp 

BGP-4 server (RFC 4271).

Division of labour

Rust owns the session: TCP framing, OPEN validation, capability and hold-time negotiation, the KEEPALIVE cadence, hold-timer expiry, and NOTIFICATION on error. None of that requires reasoning and all of it has to be right on a millisecond budget, so none of it is delegated to the model.

The LLM owns the content: whether to peer with this neighbour at all, and which routes to announce or withdraw. That is why there is no RIB here and why one is not planned — the root CLAUDE.md forbids protocols from implementing storage, and a RIB is storage. Route state, if a deployment wants any, belongs in the generic SQLite facility or in server memory, reached through actions.

Session flow

TCP accept                        -> Connect
peer OPEN, validated + negotiated -> bgp_open event -> our OPEN + KEEPALIVE -> OpenConfirm
peer KEEPALIVE                    -> Established -> bgp_established event
peer UPDATE                       -> bgp_update event
hold timer expires                -> NOTIFICATION 4/0, close

Sending a KEEPALIVE immediately after our OPEN is the step RFC 4271 section 8.2.2 requires to reach OpenConfirm, and it was missing: the old implementation only ever sent a KEEPALIVE in reply to one, so a peer that waits for ours before sending its own would deadlock.

Concurrency

The write half is owned by a dedicated task fed by an unbounded channel, so the keepalive ticker keeps the session alive while the read loop is blocked in an LLM call. Sharing a TcpStream behind a lock would have meant holding that lock across the LLM await.

Modules

actions

BGP protocol actions.

wire

BGP-4 wire format: encoding, decoding, and the model-facing JSON projection.

Structs

BgpConfig

Operator-supplied identity for this speaker.

BgpServer

BGP server that handles routing protocol sessions under LLM policy control.