[m54 merge] Set QUIC connection's last_send_for_timeout_ to the send time of the first sent packet …

net/quic/core/quic_connection.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/quic/core/quic_connection.h"
 
 #include <string.h>
 #include <sys/types.h>
 
 #include <algorithm>
@@ skipping 1653 matching lines @@
     }
   }
   if (result.status != WRITE_STATUS_ERROR && debug_visitor_ != nullptr) {
     // Pass the write result to the visitor.
     debug_visitor_->OnPacketSent(*packet, packet->original_path_id,
                                  packet->original_packet_number,
                                  packet->transmission_type, packet_send_time);
   }
   if (packet->transmission_type == NOT_RETRANSMISSION) {
     time_of_last_sent_new_packet_ = packet_send_time;
+    if (!FLAGS_quic_better_last_send_for_timeout) {
+      if (IsRetransmittable(*packet) == HAS_RETRANSMITTABLE_DATA &&
+          last_send_for_timeout_ <= time_of_last_received_packet_) {
+        last_send_for_timeout_ = packet_send_time;
+      }
+    }
+  }
+  if (FLAGS_quic_better_last_send_for_timeout) {
+    // Only adjust the last sent time (for the purpose of tracking the idle
+    // timeout) if this is the first retransmittable packet sent after a
+    // packet is received. If it were updated on every sent packet, then
+    // sending into a black hole might never timeout.
     if (IsRetransmittable(*packet) == HAS_RETRANSMITTABLE_DATA &&
         last_send_for_timeout_ <= time_of_last_received_packet_) {
       last_send_for_timeout_ = packet_send_time;
     }
   }
   SetPingAlarm();
   MaybeSetMtuAlarm();
   DVLOG(1) << ENDPOINT << "time we began writing last sent packet: "
            << packet_send_time.ToDebuggingValue();
 
@@ skipping 517 matching lines @@
       return;
     }
   }
 
   SetTimeoutAlarm();
 }
 
 void QuicConnection::SetTimeoutAlarm() {
   QuicTime time_of_last_packet =
       max(time_of_last_received_packet_, time_of_last_sent_new_packet_);
+  if (FLAGS_quic_better_last_send_for_timeout) {
+    time_of_last_packet =
+        max(time_of_last_received_packet_, last_send_for_timeout_);
+  }
 
   QuicTime deadline = time_of_last_packet + idle_network_timeout_;
   if (!handshake_timeout_.IsInfinite()) {
     deadline =
         min(deadline, stats_.connection_creation_time + handshake_timeout_);
   }
 
   timeout_alarm_->Update(deadline, QuicTime::Delta::Zero());
 }
 
@@ skipping 332 matching lines @@
 
 void QuicConnection::CheckIfApplicationLimited() {
   if (queued_packets_.empty() &&
       !sent_packet_manager_->HasPendingRetransmissions() &&
       !visitor_->WillingAndAbleToWrite()) {
     sent_packet_manager_->OnApplicationLimited();
   }
 }
 
 }  // namespace net