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

net/udp/udp_client_socket.cc

 // Copyright (c) 2011 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/udp/udp_client_socket.h"
 
 #include "net/base/net_errors.h"
 #include "net/log/net_log.h"
 
 namespace net {
 
 UDPClientSocket::UDPClientSocket(DatagramSocket::BindType bind_type,
                                  const RandIntCallback& rand_int_cb,
                                  net::NetLog* net_log,
                                  const net::NetLog::Source& source)
     : socket_(bind_type, rand_int_cb, net_log, source) {
 }
 
 UDPClientSocket::~UDPClientSocket() {
 }
 
 int UDPClientSocket::BindToNetwork(
     NetworkChangeNotifier::NetworkHandle network) {
   return socket_.BindToNetwork(network);
 }
 
+int UDPClientSocket::BindToDefaultNetwork() {
+  NetworkChangeNotifier::NetworkHandle network =
+      NetworkChangeNotifier::GetDefaultNetwork();
+  return BindToNetwork(network);

[Ryan Hamilton, 2015/11/18 22:23:36]

I'm not sure there is much benefit to this method since it seems to be
equivalent to:

socket->BindToNetwork(NetworkChangeNotifier::GetDefaultNetwork());

I think it would be cleaner to just use the method. It also means that in
QuicStreamFactory instead of passing in kInvalid and then checking to see if
network = kInvalue and then possibly calling this method, you could just pass
NetworkChangeNotifier::GetDefaultNetwork() into the Create socket method.

[pauljensen, 2015/11/19 15:25:43]

Jana's implementation and Ryan's suggestion both suffer from a race between
getting the default and binding to it, and the default changing.  This was the
point of my
https://codereview.chromium.org/1416213003/diff/1/net/udp/udp_client_socket.c...

[Jana, 2015/11/21 02:21:22]

What Paul said. Paul CL will be submitted before mine, so I will use whatever
that CL has.

+}
+
 int UDPClientSocket::Connect(const IPEndPoint& address) {
   int rv = socket_.Open(address.GetFamily());
   if (rv != OK)
     return rv;
   return socket_.Connect(address);
 }
 
 int UDPClientSocket::Read(IOBuffer* buf,
                           int buf_len,
                           const CompletionCallback& callback) {
@@ skipping 30 matching lines @@
   return socket_.NetLog();
 }
 
 #if defined(OS_WIN)
 void UDPClientSocket::UseNonBlockingIO() {
   socket_.UseNonBlockingIO();
 }
 #endif
 
 }  // namespace net