commit dd1eb2e1ece1db1e0f221cca0317014028756967
author Victor Boivie <boivie@webrtc.org> Thu Sep 01 13:00:28 2022
committer WebRTC LUCI CQ <webrtc-scoped@luci-project-accounts.iam.gserviceaccount.com> Mon Sep 05 10:52:00 2022
tree 45833324cc52c2e8c082134479211f04b112494d
parent 1e6965a8572e338b3f2229ce7c957676e2b8508b

dcsctp: Send buffered data directly on response

When a stream reset response has been received, this may result
in unpausing the streams (either because it was successful or
because it failed - but streams will be unpaused). Directly after
receiving the response, send out any pending chunks that are
ready to be sent.

Before this CL, they would eventually be sent out, but that is
unnecessary and undeterministic.

Bug: webrtc:14277
Change-Id: Ic1ab38bc3cea96cfec7419e25001f12807523a3a
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/273800
Commit-Queue: Victor Boivie <boivie@webrtc.org>
Reviewed-by: Florent Castelli <orphis@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#38009}

net/dcsctp/socket/dcsctp_socket.cc

diff --git a/net/dcsctp/socket/dcsctp_socket.cc b/net/dcsctp/socket/dcsctp_socket.cc
index d77e591..f36e26d 100644
--- a/net/dcsctp/socket/dcsctp_socket.cc
+++ b/net/dcsctp/socket/dcsctp_socket.cc
@@ -1541,6 +1541,7 @@
 void DcSctpSocket::HandleReconfig(
     const CommonHeader& header,
     const SctpPacket::ChunkDescriptor& descriptor) {
+  TimeMs now = callbacks_.TimeMillis();
   absl::optional<ReConfigChunk> chunk = ReConfigChunk::Parse(descriptor.data);
   if (ValidateParseSuccess(chunk) && ValidateHasTCB()) {
     tcb_->stream_reset_handler().HandleReConfig(*std::move(chunk));
@@ -1549,6 +1550,9 @@
     // that were waiting for this request to finish, continue resetting them.
     MaybeSendResetStreamsRequest();
   }
+  // If a response was processed, pending to-be-reset streams may now have
+  // become unpaused. Try to send more DATA chunks.
+  tcb_->SendBufferedPackets(now);
 }
 
 void DcSctpSocket::HandleShutdown(

net/dcsctp/socket/dcsctp_socket_test.cc

diff --git a/net/dcsctp/socket/dcsctp_socket_test.cc b/net/dcsctp/socket/dcsctp_socket_test.cc
index 46ac4bd..f38624d 100644
--- a/net/dcsctp/socket/dcsctp_socket_test.cc
+++ b/net/dcsctp/socket/dcsctp_socket_test.cc
@@ -2815,5 +2815,39 @@
   EXPECT_EQ(msg3->payload().size(), kSmallMessageSize);
 }
 
+TEST(DcSctpSocketTest, ResetStreamsWithPausedSenderResumesWhenPerformed) {
+  SocketUnderTest a("A");
+  SocketUnderTest z("Z");
+
+  ConnectSockets(a, z);
+
+  a.socket.Send(DcSctpMessage(StreamID(1), PPID(51),
+                              std::vector<uint8_t>(kSmallMessageSize)),
+                {});
+
+  a.socket.ResetStreams(std::vector<StreamID>({StreamID(1)}));
+
+  // Will be queued, as the stream has an outstanding reset operation.
+  a.socket.Send(DcSctpMessage(StreamID(1), PPID(52),
+                              std::vector<uint8_t>(kSmallMessageSize)),
+                {});
+
+  EXPECT_CALL(a.cb, OnStreamsResetPerformed(ElementsAre(StreamID(1))));
+  EXPECT_CALL(z.cb, OnIncomingStreamsReset(ElementsAre(StreamID(1))));
+  ExchangeMessages(a, z);
+
+  absl::optional<DcSctpMessage> msg1 = z.cb.ConsumeReceivedMessage();
+  ASSERT_TRUE(msg1.has_value());
+  EXPECT_EQ(msg1->stream_id(), StreamID(1));
+  EXPECT_EQ(msg1->ppid(), PPID(51));
+  EXPECT_EQ(msg1->payload().size(), kSmallMessageSize);
+
+  absl::optional<DcSctpMessage> msg2 = z.cb.ConsumeReceivedMessage();
+  ASSERT_TRUE(msg2.has_value());
+  EXPECT_EQ(msg2->stream_id(), StreamID(1));
+  EXPECT_EQ(msg2->ppid(), PPID(52));
+  EXPECT_EQ(msg2->payload().size(), kSmallMessageSize);
+}
+
 }  // namespace
 }  // namespace dcsctp