Only inform QUIC's SentPacketManager of packets that are actually sent, not those that failed to be…

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 1589 matching lines @@
     ++stats_.packets_discarded;
     return true;
   }
   // Termination packets are encrypted and saved, so don't exit early.
   const bool is_termination_packet = IsTerminationPacket(*packet);
   if (writer_->IsWriteBlocked() && !is_termination_packet) {
     return false;
   }
 
   QuicPacketNumber packet_number = packet->packet_number;
+  // TODO(ianswett): Remove packet_number_of_last_sent_packet_ because it's
+  // redundant to SentPacketManager_->GetLargestPacket in most cases, and wrong
+  // for multipath.
   DCHECK_LE(packet_number_of_last_sent_packet_, packet_number);
   packet_number_of_last_sent_packet_ = packet_number;
 
   QuicPacketLength encrypted_length = packet->encrypted_length;
   // Termination packets are eventually owned by TimeWaitListManager.
   // Others are deleted at the end of this call.
   if (is_termination_packet) {
     if (termination_packets_.get() == nullptr) {
       termination_packets_.reset(
           new std::vector<std::unique_ptr<QuicEncryptedPacket>>);
@@ skipping 37 matching lines @@
   if (result.status == WRITE_STATUS_BLOCKED) {
     visitor_->OnWriteBlocked();
     // If the socket buffers the the data, then the packet should not
     // be queued and sent again, which would result in an unnecessary
     // duplicate packet being sent.  The helper must call OnCanWrite
     // when the write completes, and OnWriteError if an error occurs.
     if (!writer_->IsWriteBlockedDataBuffered()) {
       return false;
     }
   }
+
+  if (FLAGS_quic_only_track_sent_packets) {
+    // In some cases, an MTU probe can cause EMSGSIZE. This indicates that the
+    // MTU discovery is permanently unsuccessful.
+    if (FLAGS_graceful_emsgsize_on_mtu_probe &&
+        result.status == WRITE_STATUS_ERROR &&
+        result.error_code == kMessageTooBigErrorCode &&
+        packet->retransmittable_frames.empty() &&
+        packet->encrypted_length > long_term_mtu_) {
+      mtu_discovery_target_ = 0;
+      mtu_discovery_alarm_->Cancel();
+      // The write failed, but the writer is not blocked, so return true.
+      return true;
+    }
+
+    if (result.status == WRITE_STATUS_ERROR) {
+      OnWriteError(result.error_code);
+      DLOG(ERROR) << ENDPOINT << "failed writing " << encrypted_length
+                  << " from host "
+                  << (self_address().address().empty()
+                          ? " empty address "
+                          : self_address().ToStringWithoutPort())
+                  << " to address " << peer_address().ToString()
+                  << " with error code " << result.error_code;
+      return false;
+    }
+  }
+
   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 &&
@@ skipping 31 matching lines @@
       sent_packet_manager_->GetLeastUnacked(packet->path_id),
       sent_packet_manager_->EstimateMaxPacketsInFlight(max_packet_length()));
 
   stats_.bytes_sent += result.bytes_written;
   ++stats_.packets_sent;
   if (packet->transmission_type != NOT_RETRANSMISSION) {
     stats_.bytes_retransmitted += result.bytes_written;
     ++stats_.packets_retransmitted;
   }
 
-  // In some cases, an MTU probe can cause ERR_MSG_TOO_BIG. This indicates that
-  // the MTU discovery is permanently unsuccessful.
-  if (FLAGS_graceful_emsgsize_on_mtu_probe &&
-      result.status == WRITE_STATUS_ERROR &&
-      result.error_code == kMessageTooBigErrorCode &&
-      packet->retransmittable_frames.empty() &&
-      packet->encrypted_length > long_term_mtu_) {
-    mtu_discovery_target_ = 0;
-    mtu_discovery_alarm_->Cancel();
-    return true;
-  }
+  if (!FLAGS_quic_only_track_sent_packets) {
+    // In some cases, an MTU probe can cause EMSGSIZE. This indicates that the
+    // MTU discovery is permanently unsuccessful.
+    if (FLAGS_graceful_emsgsize_on_mtu_probe &&
+        result.status == WRITE_STATUS_ERROR &&
+        result.error_code == kMessageTooBigErrorCode &&
+        packet->retransmittable_frames.empty() &&
+        packet->encrypted_length > long_term_mtu_) {
+      mtu_discovery_target_ = 0;
+      mtu_discovery_alarm_->Cancel();
+      return true;
+    }
 
-  if (result.status == WRITE_STATUS_ERROR) {
-    OnWriteError(result.error_code);
-    DLOG(ERROR) << ENDPOINT << "failed writing " << encrypted_length
-                << " bytes "
-                << " from host " << (self_address().address().empty()
-                                         ? " empty address "
-                                         : self_address().ToStringWithoutPort())
-                << " to address " << peer_address().ToString()
-                << " with error code " << result.error_code;
-    return false;
+    if (result.status == WRITE_STATUS_ERROR) {
+      OnWriteError(result.error_code);
+      DLOG(ERROR) << ENDPOINT << "failed writing " << encrypted_length
+                  << " from host "
+                  << (self_address().address().empty()
+                          ? " empty address "
+                          : self_address().ToStringWithoutPort())
+                  << " to address " << peer_address().ToString()
+                  << " with error code " << result.error_code;
+      return false;
+    }
   }
 
   return true;
 }
 
 bool QuicConnection::ShouldDiscardPacket(const SerializedPacket& packet) {
   if (!connected_) {
     DVLOG(1) << ENDPOINT << "Not sending packet as connection is disconnected.";
     return true;
   }
@@ skipping 776 matching lines @@
 
 void QuicConnection::CheckIfApplicationLimited() {
   if (queued_packets_.empty() &&
       !sent_packet_manager_->HasPendingRetransmissions() &&
       !visitor_->WillingAndAbleToWrite()) {
     sent_packet_manager_->OnApplicationLimited();
   }
 }
 
 }  // namespace net