dcsctp: Only process meaningful FORWARD-TSN
Similar to change I602a8552a9a4c853684fcf105309ec3d8073f2c2, which
ensured that only new DATA chunks would be processed by the reassembly
queue by utilizing the data tracker, the same is done for FORWARD-TSN
chunks.
By having the data tracker gate keeping what is provided to the
reassembly queue, the reassembly queue can be simplified as well, which
is an added bonus, by removing last_assembled_tsn_watermark_ and
reassembled_messages_ as those were protecting the queue from
re-delivering messages it had already delivered, but as now the data
tracker would ensure that it wouldn't re-process DATA/FORWARD-TSNs, that
would have the same effect. In this CL, we will still update those
variables and save to the handover state, but not actually read from
them, and then when this change has been rolled out on the servers, I
can remove the variables as well.
The core change is to move validation from ReassemblyQueue::Handle
to DataTracker::HandleForwardTsn.
Some tests have been moved/replicated into data_tracker_test.cc to
ensure that it catches the issues that the reassembly queue did earlier.
Bug: webrtc:14600
Change-Id: I75c1d5911185d594f73c8b1e6bcf776e88f5b7c7
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/321603
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Reviewed-by: Harald Alvestrand <hta@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#40856}
diff --git a/net/dcsctp/rx/data_tracker.h b/net/dcsctp/rx/data_tracker.h
index e07e1e3..62a1232 100644
--- a/net/dcsctp/rx/data_tracker.h
+++ b/net/dcsctp/rx/data_tracker.h
@@ -74,8 +74,9 @@
// Called at the end of processing an SCTP packet.
void ObservePacketEnd();
- // Called for incoming FORWARD-TSN/I-FORWARD-TSN chunks
- void HandleForwardTsn(TSN new_cumulative_ack);
+ // Called for incoming FORWARD-TSN/I-FORWARD-TSN chunks. Indicates if the
+ // chunk had any effect.
+ bool HandleForwardTsn(TSN new_cumulative_ack);
// Indicates if a SACK should be sent. There may be other reasons to send a
// SACK, but if this function indicates so, it should be sent as soon as
