# sctp-proto

Low-level protocol logic for the SCTP protocol

sctp-proto contains a fully deterministic implementation of SCTP protocol logic. It contains
no networking code and does not get any relevant timestamps from the operating system. Most
users may want to use the futures-based sctp-async API instead.

The main entry point is [Endpoint], which manages associations for a single socket. Use
[Endpoint::connect] to initiate outgoing associations, or provide a [ServerConfig] to
accept incoming ones. Incoming UDP datagrams are fed to [Endpoint::handle], which either
creates a new [Association] or returns an event to pass to an existing one.

[Association] holds the protocol state for a single SCTP association. It produces
[Event]s and outgoing packets via polling methods ([Association::poll],
[Association::poll_transmit]). Each association contains multiple [Stream]s for
reading and writing data.

[Endpoint]: https://docs.rs/sctp-proto/latest/sctp_proto/struct.Endpoint.html
[Endpoint::connect]: https://docs.rs/sctp-proto/latest/sctp_proto/struct.Endpoint.html#method.connect
[Endpoint::handle]: https://docs.rs/sctp-proto/latest/sctp_proto/struct.Endpoint.html#method.handle
[ServerConfig]: https://docs.rs/sctp-proto/latest/sctp_proto/struct.ServerConfig.html
[Association]: https://docs.rs/sctp-proto/latest/sctp_proto/struct.Association.html
[Association::poll]: https://docs.rs/sctp-proto/latest/sctp_proto/struct.Association.html#method.poll
[Association::poll_transmit]: https://docs.rs/sctp-proto/latest/sctp_proto/struct.Association.html#method.poll_transmit
[Event]: https://docs.rs/sctp-proto/latest/sctp_proto/enum.Event.html
[Stream]: https://docs.rs/sctp-proto/latest/sctp_proto/struct.Stream.html

### Status

This crate is maintained by the [str0m] project, which has been using it since
January 2023. Other consumers include [ex_sctp] for Elixir WebRTC. The crate
is kept in sync with [rtc-sctp] where possible to share bug fixes.

Originally written by Rain Liu as a Sans-IO implementation of SCTP for the
webrtc-rs ecosystem, this crate predates `rtc-sctp` in the `webrtc-rs/rtc`
monorepo, which was later derived from this work. Maintenance was transferred
to the str0m maintainers in January 2026.

[str0m]: https://crates.io/crates/str0m
[ex_sctp]: https://github.com/elixir-webrtc/ex_sctp
[rtc-sctp]: https://github.com/webrtc-rs/rtc/tree/master/rtc-sctp

License: MIT/Apache-2.0