sipx-transport

Async SIP transports: UDP, TCP, TLS, WebSocket, experimental QUIC, RFC 3263 resolution, and bounded live endpoint operations.

What this is

The I/O driver for sipx-sip. It owns sockets, connection reuse, target resolution, timers, and capture while feeding received bytes and fired timers into the sans-I/O transaction core. The same bounded, redacted capture path can send best-effort HEP3 datagrams to an operator-owned collector without moving collector I/O into a SIP timer path.

An embedding host can atomically rotate the identity used by new TLS and secure-WebSocket handshakes, observe parsed messages and connection transitions through one bounded non-blocking receiver, install an immutable pre-transaction request policy, and replace a bounded source-prefix admission generation before parsing or handshake work. Existing connections are not silently renegotiated or reclassified.

Stability

The supported and experimental surfaces are maintained in the crate-level Stability section. That is the contract; it is linked rather than copied here so the two cannot drift.

Deliberately absent

This crate does not decide registration, dialog, call, or media behavior. Those layers consume its endpoint and incoming-message interfaces without moving their policy into the socket driver.

See also

• docs/specs/sip-transport.md — transport and pooling rules.
• docs/specs/observability-export.md — HEP3 export and application-owned RTCP quality hooks.
• docs/designs/live-endpoint-policy.md — ownership and limits of identity rotation, observation, request policy, and source admission.
• docs/specs/sip-quic.md — sipx's experimental QUIC mapping.
• sipx-sip — the core driven by these transports.