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}
diff --git a/net/dcsctp/rx/reassembly_queue.h b/net/dcsctp/rx/reassembly_queue.h
index b752e53..25cda70 100644
--- a/net/dcsctp/rx/reassembly_queue.h
+++ b/net/dcsctp/rx/reassembly_queue.h
@@ -104,8 +104,8 @@
// data.
size_t queued_bytes() const { return queued_bytes_; }
- // The remaining bytes until the queue is full.
- size_t remaining_bytes() const { return max_size_bytes_ - queued_bytes_; }
+ // The remaining bytes until the queue has reached the watermark limit.
+ size_t remaining_bytes() const { return watermark_bytes_ - queued_bytes_; }
// Indicates if the queue is full. Data should not be added to the queue when
// it's full.
