Migrates QUIC sessions to a new network when old network is (about to be) disconnected.

net/quic/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/quic_connection.h"
 
 #include <string.h>
 #include <sys/types.h>
 
 #include <algorithm>
@@ skipping 135 matching lines @@
   QuicConnection* connection_;
 
   DISALLOW_COPY_AND_ASSIGN(TimeoutAlarm);
 };
 
 class PingAlarm : public QuicAlarm::Delegate {
  public:
   explicit PingAlarm(QuicConnection* connection) : connection_(connection) {}
 
   QuicTime OnAlarm() override {
-    connection_->SendPing();
+    connection_->OnPingTimeout();
     return QuicTime::Zero();
   }
 
  private:
   QuicConnection* connection_;
 
   DISALLOW_COPY_AND_ASSIGN(PingAlarm);
 };
 
 class MtuDiscoveryAlarm : public QuicAlarm::Delegate {
@@ skipping 1637 matching lines @@
       has_forward_secure_encrypter_ &&
       packet->packet_number >= first_required_forward_secure_packet_ - 1) {
     SetDefaultEncryptionLevel(ENCRYPTION_FORWARD_SECURE);
   }
 }
 
 PeerAddressChangeType QuicConnection::DeterminePeerAddressChangeType() {
   return UNKNOWN;
 }
 
+void QuicConnection::OnPingTimeout() {
+  if (!retransmission_alarm_->IsSet()) {
+    SendPing();
+  }
+}
+
 void QuicConnection::SendPing() {
-  if (retransmission_alarm_->IsSet()) {
-    return;
-  }
   packet_generator_.AddControlFrame(QuicFrame(QuicPingFrame()));
 }
 
 void QuicConnection::SendAck() {
   ack_alarm_->Cancel();
   ack_queued_ = false;
   stop_waiting_count_ = 0;
   num_retransmittable_packets_received_since_last_ack_sent_ = 0;
   num_packets_received_since_last_ack_sent_ = 0;
 
@@ skipping 572 matching lines @@
   SendMtuDiscoveryPacket(mtu_discovery_target_);
 
   DCHECK(!mtu_discovery_alarm_->IsSet());
 }
 
 bool QuicConnection::ack_frame_updated() const {
   return received_packet_manager_.ack_frame_updated();
 }
 
 }  // namespace net