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

net/quic/quic_chromium_client_session.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_chromium_client_session.h"
 
 #include "base/callback_helpers.h"
 #include "base/location.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/metrics/sparse_histogram.h"
@@ skipping 22 matching lines @@
 
 namespace {
 
 // The length of time to wait for a 0-RTT handshake to complete
 // before allowing the requests to possibly proceed over TCP.
 const int k0RttHandshakeTimeoutMs = 300;
 
 // IPv6 packets have an additional 20 bytes of overhead than IPv4 packets.
 const size_t kAdditionalOverheadForIPv6 = 20;
 
+// Maximum number of Readers that are created for any session due to
+// connection migration. A new Reader is created every time this endpoint's
+// IP address changes.
+const size_t kMaxReadersPerQuicSession = 5;
+
 // Histograms for tracking down the crashes from http://crbug.com/354669
 // Note: these values must be kept in sync with the corresponding values in:
 // tools/metrics/histograms/histograms.xml
 enum Location {
   DESTRUCTOR = 0,
   ADD_OBSERVER = 1,
   TRY_CREATE_STREAM = 2,
   CREATE_OUTGOING_RELIABLE_STREAM = 3,
   NOTIFY_FACTORY_OF_SESSION_CLOSED_LATER = 4,
   NOTIFY_FACTORY_OF_SESSION_CLOSED = 5,
@@ skipping 115 matching lines @@
     const QuicConfig& config,
     QuicCryptoClientConfig* crypto_config,
     const char* const connection_description,
     base::TimeTicks dns_resolution_end_time,
     base::TaskRunner* task_runner,
     NetLog* net_log)
     : QuicClientSessionBase(connection, config),
       server_id_(server_id),
       require_confirmation_(false),
       stream_factory_(stream_factory),
-      socket_(socket.Pass()),
       transport_security_state_(transport_security_state),
       server_info_(server_info.Pass()),
       num_total_streams_(0),
       task_runner_(task_runner),
       net_log_(BoundNetLog::Make(net_log, NetLog::SOURCE_QUIC_SESSION)),
-      packet_reader_(socket_.get(), this, net_log_),
       dns_resolution_end_time_(dns_resolution_end_time),
       logger_(new QuicConnectionLogger(this, connection_description, net_log_)),
       going_away_(false),
       disabled_reason_(QUIC_DISABLED_NOT),
       weak_factory_(this) {
+  sockets_[0] = socket.Pass();

[Ryan Hamilton, 2015/09/08 04:09:37]

nit: sockets_.push_back(socket.Pass())

[Jana, 2015/11/17 01:50:08]

Done.

+  packet_readers_[0].reset(
+      new QuicPacketReader(sockets_[0].get(), this, net_log_));

[Ryan Hamilton, 2015/09/08 04:09:37]

ditto

[Jana, 2015/11/17 01:50:08]

Done.

   crypto_stream_.reset(
       crypto_client_stream_factory
           ? crypto_client_stream_factory->CreateQuicCryptoClientStream(
                 server_id, this, crypto_config)
           : new QuicCryptoClientStream(
                 server_id, this,
                 new ProofVerifyContextChromium(cert_verify_flags, net_log_),
                 crypto_config));
   connection->set_debug_visitor(logger_.get());
   net_log_.BeginEvent(NetLog::TYPE_QUIC_SESSION,
@@ skipping 537 matching lines @@
   } else if (error == QUIC_PUBLIC_RESET) {
     disabled_reason_ = QUIC_DISABLED_PUBLIC_RESET_POST_HANDSHAKE;
   }
 
   UMA_HISTOGRAM_SPARSE_SLOWLY("Net.QuicSession.QuicVersion",
                               connection()->version());
   NotifyFactoryOfSessionGoingAway();
   if (!callback_.is_null()) {
     base::ResetAndReturn(&callback_).Run(ERR_QUIC_PROTOCOL_ERROR);
   }
-  socket_->Close();
+
+  for (size_t i = 0; i < sockets_.size(); ++i) {

[Ryan Hamilton, 2015/09/08 04:09:37]

nit: for (Socket socket : sockets) { ... }

[Jana, 2015/11/17 01:50:08]

Done.

+    sockets_[i]->Close();
+  }
   QuicSession::OnConnectionClosed(error, from_peer);
   DCHECK(dynamic_streams().empty());
   CloseAllStreams(ERR_UNEXPECTED);
   CloseAllObservers(ERR_UNEXPECTED);
   NotifyFactoryOfSessionClosedLater();
 }
 
 void QuicChromiumClientSession::OnSuccessfulVersionNegotiation(
     const QuicVersion& version) {
   logger_->OnSuccessfulVersionNegotiation(version);
@@ skipping 23 matching lines @@
   const ProofVerifyDetailsChromium* verify_details_chromium =
       reinterpret_cast<const ProofVerifyDetailsChromium*>(&verify_details);
   CertVerifyResult* result_copy = new CertVerifyResult;
   result_copy->CopyFrom(verify_details_chromium->cert_verify_result);
   cert_verify_result_.reset(result_copy);
   pinning_failure_log_ = verify_details_chromium->pinning_failure_log;
   logger_->OnCertificateVerified(*cert_verify_result_);
 }
 
 void QuicChromiumClientSession::StartReading() {
-  packet_reader_.StartReading();
+  for (size_t i = 0; i < packet_readers_.size(); ++i) {

[Ryan Hamilton, 2015/09/08 04:09:37]

nit: c++11 foreach loop

[Jana, 2015/11/17 01:50:08]

Done.

+    packet_readers_[i]->StartReading();
+  }
 }
 
 void QuicChromiumClientSession::CloseSessionOnError(int error,
                                                     QuicErrorCode quic_error) {
   RecordAndCloseSessionOnError(error, quic_error);
   NotifyFactoryOfSessionClosed();
 }
 
 void QuicChromiumClientSession::CloseSessionOnErrorAndNotifyFactoryLater(
     int error,
@@ skipping 144 matching lines @@
   if (IsCryptoHandshakeConfirmed())
     return;
 
   // TODO(rch): re-enable this code once beta is cut.
   //  if (stream_factory_)
   //    stream_factory_->OnSessionConnectTimeout(this);
   //  CloseAllStreams(ERR_QUIC_HANDSHAKE_FAILED);
   //  DCHECK_EQ(0u, GetNumOpenStreams());
 }
 
+void QuicChromiumClientSession::AddSocket(
+    scoped_ptr<DatagramClientSocket> socket) {
+  size_t num_sockets = sockets_.size();
+  sockets_.resize(num_sockets + 1);
+  sockets_[num_sockets - 1] = socket.Pass();

[Ryan Hamilton, 2015/09/08 04:09:37]

I think you can just do sockets_.push_back(socket.Pass());

[Jana, 2015/11/17 01:50:08]

Done.

+}
+
+bool QuicChromiumClientSession::AddPacketReader(QuicPacketReader* reader) {
+  size_t num_readers = packet_readers_.size();
+  if (num_readers >= kMaxReadersPerQuicSession) {
+    return false;
+  }
+  packet_readers_.resize(num_readers + 1);
+  packet_readers_[num_readers - 1].reset(reader);
+  return true;
+}

[Ryan Hamilton, 2015/09/08 04:09:37]

It's a bit surprising that the AddSocket method returns void, but the AddReader
returns bool. Perhaps a single method which takes the Socket, Reader and Writer?

Should the size of readers_ and sockets_ be the same? If so, perhaps some
DCHECKs.

[Jana, 2015/11/17 01:50:08]

Yeah, this wasn't great, so I cleaned it up now, PTAL.

+
 }  // namespace net