Crate rtc_sctp 

SCTP for the Sans-I/O WebRTC stack.

The Stream Control Transmission Protocol (RFC 4960) with the extensions WebRTC data channels need: partial reliability (RFC 3758) and stream reset / reconfiguration (RFC 6525). In WebRTC, SCTP runs over DTLS rather than over IP, and carries the data channels described by rtc-datachannel.

This is a fully deterministic implementation of the protocol logic. It contains no networking code and reads no clock of its own: you feed it datagrams and time, and poll it for the datagrams and events it produces. That is what makes it testable without a network and reusable under any executor.

Structure

• Endpoint — the protocol state for one socket. It holds configuration and dispatches inbound datagrams to the right association.
• Association — the bulk of the logic for a single association: handshake, congestion control, retransmission, and its streams.
• Stream — one stream’s reads, writes and reliability settings.
• Chunks — a reassembled inbound message, delivered once every fragment has arrived.

Example

Configuration is plain data, and the association is driven entirely by the caller — feed it datagrams and time, poll it for output:

use rtc_sctp::{EndpointConfig, TransportConfig};
use std::sync::Arc;

let transport = TransportConfig::default()
    .with_max_message_size(65_536)
    .with_max_num_outbound_streams(1024);

let endpoint_config = Arc::new(EndpointConfig::new());
assert_eq!(transport.max_message_size(), 65_536);

Most applications do not depend on this crate directly — the rtc crate drives it as one layer of the peer-connection pipeline and exposes data channels, and webrtc wraps that in an async API.

Structs

Association

Association represents an SCTP association

AssociationEvent

Events sent from an Endpoint to an Association

AssociationHandle

Internal identifier for an Association currently associated with an endpoint

AssociationStats

Association statistics

Chunk

A chunk of data from the stream

ChunkPayloadData

ChunkPayloadData represents an SCTP Chunk of type DATA

Chunks

Chunks is a set of chunks that share the same SSN

ClientConfig

Configuration for outgoing associations

Endpoint

The main entry point to the library

EndpointConfig

Global configuration for the endpoint, affecting all associations

EndpointEvent

Events sent from an Association to an Endpoint

ErrorCauseCode

ErrorCauseCode is a cause code that appears in either a ERROR or ABORT chunk

ServerConfig

Parameters governing incoming associations

Stream

Stream represents an SCTP stream

StreamState

StreamState represents the state of an SCTP stream

TimerConfig

Retransmission limits for the association’s timers.

TransportConfig

Config collects the arguments to create_association construction into a single structure

Enums

AssociationError

Reasons why an association might be lost

ConnectError

Errors in the parameters being used to create a new association

DatagramEvent

Event resulting from processing a single datagram

Event

Events of interest to the application

Payload

Payload in Incoming/outgoing Transmit

PayloadProtocolIdentifier

PayloadProtocolIdentifier is an enum for DataChannel payload types PayloadProtocolIdentifier enums https://www.iana.org/assignments/sctp-parameters/sctp-parameters.xhtml#sctp-parameters-25

ReliabilityType

Reliability type for stream

Side

Whether an endpoint was the initiator of an association

StreamEvent

Application events about streams

Constants

MIN_DATA_PACKET_MTU

Floor for max_payload_size_for_mtu: the smallest representable padded DATA packet — the 12-byte common header, the 16-byte DATA chunk header, and a 1..=4-byte payload padded to the 4-byte chunk boundary.

Functions

max_payload_size_for_mtu

Derive an EndpointConfig::max_payload_size value from an outbound DATA-packet budget: the largest DATA packet (common header plus bundled DATA chunks) associations may emit, in bytes. Control packets (INIT, INIT ACK, SACK, RECONFIG, FORWARD TSN, shutdown) marshal without consulting this value.

Type Aliases

AssociationId

Protocol-level identifier for an Association.

StreamId

Identifier for a stream within a particular association