commit 8267724a8528646336a144197e2462a9147373b9
author Victor Boivie <boivie@webrtc.org> Sat May 29 20:14:34 2021
committer WebRTC LUCI CQ <webrtc-scoped@luci-project-accounts.iam.gserviceaccount.com> Mon May 31 14:10:34 2021
tree 595531e6eb77b9a3be5d00e71c0e8c3227e55231
parent ea72ee635016279e5fe12eebaff6d34900119154

dcsctp: Announce send buffer watermark as a_rwnd

The receive buffer mustn't be full; If it's full, and a message can't be
assembled, the socket can't accept more data. To avoid this, there is
a high watermark limit that, when reached, will make the socket only
accept chunks that advance the cumulative ack TSN.

Before this CL, the announced receiver window size in every sent SACK
was based on what the receive buffer could maximally be, which means
that in really high data rate applications, the amount of outstanding
data could actually fill the receive buffer (due to packet loss, that
prevents messages from being reassembled). As the socket started
behaving more conservatively when the high watermark limit was reached,
this resulted in unnecessary T3-RTXes. But by announcing the high
watermark limit instead, the sender will stay within it, and will have
a peer socket that behaves as expected.

Bug: webrtc:12799
Change-Id: Ife2f409914a230640217553c54f60d05843efc70
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/220762
Reviewed-by: Florent Castelli <orphis@webrtc.org>
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#34168}