Syncing sctp-proto with rtc-sctp

This document describes how to compare and synchronize changes between sctp-proto (standalone SCTP implementation) and rtc-sctp (SCTP module within the rtc monorepo).

Repository Information

Repo	URL	Commit at last sync
sctp-proto	https://github.com/webrtc-rs/sctp-proto	0f3be08 (v0.6.0)
rtc (contains rtc-sctp)	https://github.com/webrtc-rs/rtc	c0badad

Setup for Comparison

To set up the repositories for comparison:

# Clone both repositories side by side
mkdir -p ~/dev && cd ~/dev
git clone https://github.com/webrtc-rs/sctp-proto.git
git clone https://github.com/webrtc-rs/rtc.git

# Create symlink for easy comparison (optional)
cd sctp-proto
ln -s ../rtc/rtc-sctp rtc-sctp

Finding New Changes Since Last Sync

The commits listed above are the state at the time of the last sync. To find changes that have happened SINCE then:

# See what changed in rtc-sctp since the last sync
cd ~/dev/rtc
git log c0badad..HEAD -- rtc-sctp/

# See the actual diff of new changes
git diff c0badad..HEAD -- rtc-sctp/src/

Then compare those changes against the current sctp-proto to see what needs to be brought over.

Comparing the Codebases

The SCTP implementation lives in:

• sctp-proto/src/ - standalone version
• rtc/rtc-sctp/src/ - rtc monorepo version

To find all differences:

diff -rq sctp-proto/src rtc/rtc-sctp/src

To see detailed diff for a specific file:

diff -u sctp-proto/src/association/mod.rs rtc/rtc-sctp/src/association/mod.rs

Key Architectural Differences

1. Error handling: sctp-proto has local src/error.rs; rtc-sctp uses shared::error
2. Transport: sctp-proto uses Transmit struct; rtc-sctp uses TransportMessage<Payload>
3. Dependencies: sctp-proto uses FxHashMap; rtc-sctp uses HashMap

Sync Policy

When syncing, we bring over:

• Bug fixes (always)
• New features (case by case)
• Refactoring (only if beneficial)

We do NOT adopt:

• Architectural changes that would add external dependencies
• Changes to transport abstractions
• Changes that remove flexibility (e.g., hardcoded constants vs configurable)

Last Sync: 2026-01-17

Changes brought from rtc-sctp to sctp-proto:

• Bug fix: Remove invalid Eq derive from AssociationError
• Bug fix: Change poll_timeout to take &self
• Bug fix: Propagate handle_data() return value
• Feature: StreamEvent::BufferedAmountHigh with threshold methods
• Feature: Stream ID in StreamEvent::Opened
• Feature: Stream ID in Event::AssociationLost
• Feature: Event::HandshakeFailed variant
• Feature: Stream::close() convenience method
• Feature: Association::stream_ids() method