commit | c20f1563b672da0cb777141357c678562865cc5b | [log] [tgz] |
---|---|---|
author | Victor Boivie <boivie@webrtc.org> | Wed Jun 16 10:52:42 2021 |
committer | WebRTC LUCI CQ <webrtc-scoped@luci-project-accounts.iam.gserviceaccount.com> | Fri Jun 18 08:50:59 2021 |
tree | dc6e19edd3d897dcd1fdc42d526bad73a204157e | |
parent | 95c30413db93d34f0a669602a74e0dd4e129cc1a [diff] |
dcsctp: Don't sent more packets before COOKIE ACK While in the COOKIE ECHO state, there is a TCB and there might be data in the send buffer, and RFC4960 allows the COOKIE ECHO chunk to bundle additional DATA chunks in the same packet, but there mustn't be more than one such packet sent, and that packet must have a COOKIE ECHO chunk as the first chunk in it. When the COOKIE ACK chunk has been received, the socket is allowed to send multiple packets. Previously, this was state managed by the socket and not the TCB, as the socket is responsible for moving between the different states. And when the COOKIE ECHO chunk was sent, the TCB was instructed to only send a single packet by the socket. However, if there were retransmissions or anything else that could result in calling TransmissionControlBlock::SendBufferedChunks, it would do as instructed and send those, even if the socket was in a state where that wasn't allowed. When the peer was dcSCTP, this didn't cause any issues as dcSCTP tries to be tolerant in what it receives (but strict in what it sends, except for when there are bugs). When the peer was usrsctp, it would send an ABORT for each received packet that didn't have a COOKIE ECHO as the first chunk, and then restart the handshake (sending an INIT). So this resulted in a longer handshake, but the connection would eventually be correctly established and any DATA chunks that resulted in the ABORTs would've been retransmitted. By making the TCB aware of that particular state, and to make it responsible for creating the SCTP packet with the COOKIE ECHO chunk first, and also to only send a single packet when it is in that state, there will not be any way to bypass this limitation. Also, while not explicitly mentioned in the RFC, the retransmission timer will not affect resending any outstanding DATA chunks that were bundled together with the COOKIE ECHO chunk, as then there would be two timers that both would drive resending COOKIE ECHO and DATA chunks. Bug: webrtc:12880 Change-Id: I76f215a03cceab5bafe9f16eb4775f3dc68a6f05 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/222645 Reviewed-by: Harald Alvestrand <hta@webrtc.org> Commit-Queue: Victor Boivie <boivie@webrtc.org> Cr-Commit-Position: refs/heads/master@{#34329}
WebRTC is a free, open software project that provides browsers and mobile applications with Real-Time Communications (RTC) capabilities via simple APIs. The WebRTC components have been optimized to best serve this purpose.
Our mission: To enable rich, high-quality RTC applications to be developed for the browser, mobile platforms, and IoT devices, and allow them all to communicate via a common set of protocols.
The WebRTC initiative is a project supported by Google, Mozilla and Opera, amongst others.
See here for instructions on how to get started developing with the native code.
Authoritative list of directories that contain the native API header files.