net/quic/quic_server_session.cc

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "net/quic/quic_server_session.h"
   6
   7 #include "base/logging.h"
   8 #include "net/quic/crypto/cached_network_parameters.h"
   9 #include "net/quic/quic_connection.h"
  10 #include "net/quic/quic_flags.h"
  11 #include "net/quic/quic_spdy_server_stream.h"
  12 #include "net/quic/reliable_quic_stream.h"
  13
  14 namespace net {
  15
  16 QuicServerSession::QuicServerSession(const QuicConfig& config,
  17                                      QuicConnection* connection,
  18                                      QuicServerSessionVisitor* visitor)
  19     : QuicSession(connection, config),
  20       visitor_(visitor),
  21       bandwidth_estimate_sent_to_client_(QuicBandwidth::Zero()),
  22       last_scup_time_(QuicTime::Zero()),
  23       last_scup_sequence_number_(0) {}
  24
  25 QuicServerSession::~QuicServerSession() {}
  26
  27 void QuicServerSession::InitializeSession(
  28     const QuicCryptoServerConfig& crypto_config) {
  29   QuicSession::InitializeSession();
  30   crypto_stream_.reset(CreateQuicCryptoServerStream(crypto_config));
  31 }
  32
  33 QuicCryptoServerStream* QuicServerSession::CreateQuicCryptoServerStream(
  34     const QuicCryptoServerConfig& crypto_config) {
  35   return new QuicCryptoServerStream(crypto_config, this);
  36 }
  37
  38 void QuicServerSession::OnConfigNegotiated() {
  39   QuicSession::OnConfigNegotiated();
  40
  41   if (!config()->HasReceivedConnectionOptions()) {
  42     return;
  43   }
  44
  45   // If the client has provided a bandwidth estimate from the same serving
  46   // region, then pass it to the sent packet manager in preparation for possible
  47   // bandwidth resumption.
  48   const CachedNetworkParameters* cached_network_params =
  49       crypto_stream_->previous_cached_network_params();
  50   if (FLAGS_quic_enable_bandwidth_resumption_experiment &&
  51       cached_network_params != nullptr &&
  52       ContainsQuicTag(config()->ReceivedConnectionOptions(), kBWRE) &&
  53       cached_network_params->serving_region() == serving_region_) {
  54     connection()->ResumeConnectionState(*cached_network_params);
  55   }
  56
  57   if (FLAGS_enable_quic_fec &&
  58       ContainsQuicTag(config()->ReceivedConnectionOptions(), kFHDR)) {
  59     // kFHDR config maps to FEC protection always for headers stream.
  60     // TODO(jri): Add crypto stream in addition to headers for kHDR.
  61     headers_stream_->set_fec_policy(FEC_PROTECT_ALWAYS);
  62   }
  63 }
  64
  65 void QuicServerSession::OnConnectionClosed(QuicErrorCode error,
  66                                            bool from_peer) {
  67   QuicSession::OnConnectionClosed(error, from_peer);
  68   // In the unlikely event we get a connection close while doing an asynchronous
  69   // crypto event, make sure we cancel the callback.
  70   if (crypto_stream_.get() != nullptr) {
  71     crypto_stream_->CancelOutstandingCallbacks();
  72   }
  73   visitor_->OnConnectionClosed(connection()->connection_id(), error);
  74 }
  75
  76 void QuicServerSession::OnWriteBlocked() {
  77   QuicSession::OnWriteBlocked();
  78   visitor_->OnWriteBlocked(connection());
  79 }
  80
  81 void QuicServerSession::OnCongestionWindowChange(QuicTime now) {
  82   // Only send updates when the application has no data to write.
  83   if (HasDataToWrite()) {
  84     return;
  85   }
  86
  87   // If not enough time has passed since the last time we sent an update to the
  88   // client, or not enough packets have been sent, then return early.
  89   const QuicSentPacketManager& sent_packet_manager =
  90       connection()->sent_packet_manager();
  91   int64 srtt_ms =
  92       sent_packet_manager.GetRttStats()->smoothed_rtt().ToMilliseconds();
  93   int64 now_ms = now.Subtract(last_scup_time_).ToMilliseconds();
  94   int64 packets_since_last_scup =
  95       connection()->sequence_number_of_last_sent_packet() -
  96       last_scup_sequence_number_;
  97   if (now_ms < (kMinIntervalBetweenServerConfigUpdatesRTTs * srtt_ms) ||
  98       now_ms < kMinIntervalBetweenServerConfigUpdatesMs ||
  99       packets_since_last_scup < kMinPacketsBetweenServerConfigUpdates) {
 100     return;
 101   }
 102
 103   // If the bandwidth recorder does not have a valid estimate, return early.
 104   const QuicSustainedBandwidthRecorder& bandwidth_recorder =
 105       sent_packet_manager.SustainedBandwidthRecorder();
 106   if (!bandwidth_recorder.HasEstimate()) {
 107     return;
 108   }
 109
 110   // The bandwidth recorder has recorded at least one sustained bandwidth
 111   // estimate. Check that it's substantially different from the last one that
 112   // we sent to the client, and if so, send the new one.
 113   QuicBandwidth new_bandwidth_estimate = bandwidth_recorder.BandwidthEstimate();
 114
 115   int64 bandwidth_delta =
 116       std::abs(new_bandwidth_estimate.ToBitsPerSecond() -
 117                bandwidth_estimate_sent_to_client_.ToBitsPerSecond());
 118
 119   // Define "substantial" difference as a 50% increase or decrease from the
 120   // last estimate.
 121   bool substantial_difference =
 122       bandwidth_delta >
 123       0.5 * bandwidth_estimate_sent_to_client_.ToBitsPerSecond();
 124   if (!substantial_difference) {
 125     return;
 126   }
 127
 128   bandwidth_estimate_sent_to_client_ = new_bandwidth_estimate;
 129   DVLOG(1) << "Server: sending new bandwidth estimate (KBytes/s): "
 130            << bandwidth_estimate_sent_to_client_.ToKBytesPerSecond();
 131
 132   // Include max bandwidth in the update.
 133   QuicBandwidth max_bandwidth_estimate =
 134       bandwidth_recorder.MaxBandwidthEstimate();
 135   int32 max_bandwidth_timestamp = bandwidth_recorder.MaxBandwidthTimestamp();
 136
 137   // Fill the proto before passing it to the crypto stream to send.
 138   CachedNetworkParameters cached_network_params;
 139   cached_network_params.set_bandwidth_estimate_bytes_per_second(
 140       bandwidth_estimate_sent_to_client_.ToBytesPerSecond());
 141   cached_network_params.set_max_bandwidth_estimate_bytes_per_second(
 142       max_bandwidth_estimate.ToBytesPerSecond());
 143   cached_network_params.set_max_bandwidth_timestamp_seconds(
 144       max_bandwidth_timestamp);
 145   cached_network_params.set_min_rtt_ms(
 146       sent_packet_manager.GetRttStats()->min_rtt().ToMilliseconds());
 147   cached_network_params.set_previous_connection_state(
 148       bandwidth_recorder.EstimateRecordedDuringSlowStart()
 149           ? CachedNetworkParameters::SLOW_START
 150           : CachedNetworkParameters::CONGESTION_AVOIDANCE);
 151   cached_network_params.set_timestamp(
 152       connection()->clock()->WallNow().ToUNIXSeconds());
 153   if (!serving_region_.empty()) {
 154     cached_network_params.set_serving_region(serving_region_);
 155   }
 156
 157   crypto_stream_->SendServerConfigUpdate(&cached_network_params);
 158   last_scup_time_ = now;
 159   last_scup_sequence_number_ =
 160       connection()->sequence_number_of_last_sent_packet();
 161 }
 162
 163 bool QuicServerSession::ShouldCreateIncomingDataStream(QuicStreamId id) {
 164   if (id % 2 == 0) {
 165     DVLOG(1) << "Invalid incoming even stream_id:" << id;
 166     connection()->SendConnectionClose(QUIC_INVALID_STREAM_ID);
 167     return false;
 168   }
 169   if (GetNumOpenStreams() >= get_max_open_streams()) {
 170     DVLOG(1) << "Failed to create a new incoming stream with id:" << id
 171              << " Already " << GetNumOpenStreams() << " streams open (max "
 172              << get_max_open_streams() << ").";
 173     connection()->SendConnectionClose(QUIC_TOO_MANY_OPEN_STREAMS);
 174     return false;
 175   }
 176   return true;
 177 }
 178
 179 QuicDataStream* QuicServerSession::CreateIncomingDataStream(
 180     QuicStreamId id) {
 181   if (!ShouldCreateIncomingDataStream(id)) {
 182     return nullptr;
 183   }
 184
 185   return new QuicSpdyServerStream(id, this);
 186 }
 187
 188 QuicDataStream* QuicServerSession::CreateOutgoingDataStream() {
 189   DLOG(ERROR) << "Server push not yet supported";
 190   return nullptr;
 191 }
 192
 193 QuicCryptoServerStream* QuicServerSession::GetCryptoStream() {
 194   return crypto_stream_.get();
 195 }
 196
 197 }  // namespace net