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   const bool max_bandwidth_resumption =
  51       ContainsQuicTag(config()->ReceivedConnectionOptions(), kBWMX);
  52   if (cached_network_params != nullptr &&
  53       (ContainsQuicTag(config()->ReceivedConnectionOptions(), kBWRE) ||
  54        max_bandwidth_resumption) &&
  55       cached_network_params->serving_region() == serving_region_) {
  56     connection()->ResumeConnectionState(*cached_network_params,
  57                                         max_bandwidth_resumption);
  58   }
  59
  60   if (FLAGS_enable_quic_fec &&
  61       ContainsQuicTag(config()->ReceivedConnectionOptions(), kFHDR)) {
  62     // kFHDR config maps to FEC protection always for headers stream.
  63     // TODO(jri): Add crypto stream in addition to headers for kHDR.
  64     headers_stream_->set_fec_policy(FEC_PROTECT_ALWAYS);
  65   }
  66 }
  67
  68 void QuicServerSession::OnConnectionClosed(QuicErrorCode error,
  69                                            bool from_peer) {
  70   QuicSession::OnConnectionClosed(error, from_peer);
  71   // In the unlikely event we get a connection close while doing an asynchronous
  72   // crypto event, make sure we cancel the callback.
  73   if (crypto_stream_.get() != nullptr) {
  74     crypto_stream_->CancelOutstandingCallbacks();
  75   }
  76   visitor_->OnConnectionClosed(connection()->connection_id(), error);
  77 }
  78
  79 void QuicServerSession::OnWriteBlocked() {
  80   QuicSession::OnWriteBlocked();
  81   visitor_->OnWriteBlocked(connection());
  82 }
  83
  84 void QuicServerSession::OnCongestionWindowChange(QuicTime now) {
  85   // Only send updates when the application has no data to write.
  86   if (HasDataToWrite()) {
  87     return;
  88   }
  89
  90   // If not enough time has passed since the last time we sent an update to the
  91   // client, or not enough packets have been sent, then return early.
  92   const QuicSentPacketManager& sent_packet_manager =
  93       connection()->sent_packet_manager();
  94   int64 srtt_ms =
  95       sent_packet_manager.GetRttStats()->smoothed_rtt().ToMilliseconds();
  96   int64 now_ms = now.Subtract(last_scup_time_).ToMilliseconds();
  97   int64 packets_since_last_scup =
  98       connection()->sequence_number_of_last_sent_packet() -
  99       last_scup_sequence_number_;
 100   if (now_ms < (kMinIntervalBetweenServerConfigUpdatesRTTs * srtt_ms) ||
 101       now_ms < kMinIntervalBetweenServerConfigUpdatesMs ||
 102       packets_since_last_scup < kMinPacketsBetweenServerConfigUpdates) {
 103     return;
 104   }
 105
 106   // If the bandwidth recorder does not have a valid estimate, return early.
 107   const QuicSustainedBandwidthRecorder& bandwidth_recorder =
 108       sent_packet_manager.SustainedBandwidthRecorder();
 109   if (!bandwidth_recorder.HasEstimate()) {
 110     return;
 111   }
 112
 113   // The bandwidth recorder has recorded at least one sustained bandwidth
 114   // estimate. Check that it's substantially different from the last one that
 115   // we sent to the client, and if so, send the new one.
 116   QuicBandwidth new_bandwidth_estimate = bandwidth_recorder.BandwidthEstimate();
 117
 118   int64 bandwidth_delta =
 119       std::abs(new_bandwidth_estimate.ToBitsPerSecond() -
 120                bandwidth_estimate_sent_to_client_.ToBitsPerSecond());
 121
 122   // Define "substantial" difference as a 50% increase or decrease from the
 123   // last estimate.
 124   bool substantial_difference =
 125       bandwidth_delta >
 126       0.5 * bandwidth_estimate_sent_to_client_.ToBitsPerSecond();
 127   if (!substantial_difference) {
 128     return;
 129   }
 130
 131   bandwidth_estimate_sent_to_client_ = new_bandwidth_estimate;
 132   DVLOG(1) << "Server: sending new bandwidth estimate (KBytes/s): "
 133            << bandwidth_estimate_sent_to_client_.ToKBytesPerSecond();
 134
 135   // Include max bandwidth in the update.
 136   QuicBandwidth max_bandwidth_estimate =
 137       bandwidth_recorder.MaxBandwidthEstimate();
 138   int32 max_bandwidth_timestamp = bandwidth_recorder.MaxBandwidthTimestamp();
 139
 140   // Fill the proto before passing it to the crypto stream to send.
 141   CachedNetworkParameters cached_network_params;
 142   cached_network_params.set_bandwidth_estimate_bytes_per_second(
 143       bandwidth_estimate_sent_to_client_.ToBytesPerSecond());
 144   cached_network_params.set_max_bandwidth_estimate_bytes_per_second(
 145       max_bandwidth_estimate.ToBytesPerSecond());
 146   cached_network_params.set_max_bandwidth_timestamp_seconds(
 147       max_bandwidth_timestamp);
 148   cached_network_params.set_min_rtt_ms(
 149       sent_packet_manager.GetRttStats()->min_rtt().ToMilliseconds());
 150   cached_network_params.set_previous_connection_state(
 151       bandwidth_recorder.EstimateRecordedDuringSlowStart()
 152           ? CachedNetworkParameters::SLOW_START
 153           : CachedNetworkParameters::CONGESTION_AVOIDANCE);
 154   cached_network_params.set_timestamp(
 155       connection()->clock()->WallNow().ToUNIXSeconds());
 156   if (!serving_region_.empty()) {
 157     cached_network_params.set_serving_region(serving_region_);
 158   }
 159
 160   crypto_stream_->SendServerConfigUpdate(&cached_network_params);
 161
 162   connection()->OnSendConnectionState(cached_network_params);
 163
 164   last_scup_time_ = now;
 165   last_scup_sequence_number_ =
 166       connection()->sequence_number_of_last_sent_packet();
 167 }
 168
 169 bool QuicServerSession::ShouldCreateIncomingDataStream(QuicStreamId id) {
 170   if (id % 2 == 0) {
 171     DVLOG(1) << "Invalid incoming even stream_id:" << id;
 172     connection()->SendConnectionClose(QUIC_INVALID_STREAM_ID);
 173     return false;
 174   }
 175   if (GetNumOpenStreams() >= get_max_open_streams()) {
 176     DVLOG(1) << "Failed to create a new incoming stream with id:" << id
 177              << " Already " << GetNumOpenStreams() << " streams open (max "
 178              << get_max_open_streams() << ").";
 179     connection()->SendConnectionClose(QUIC_TOO_MANY_OPEN_STREAMS);
 180     return false;
 181   }
 182   return true;
 183 }
 184
 185 QuicDataStream* QuicServerSession::CreateIncomingDataStream(
 186     QuicStreamId id) {
 187   if (!ShouldCreateIncomingDataStream(id)) {
 188     return nullptr;
 189   }
 190
 191   return new QuicSpdyServerStream(id, this);
 192 }
 193
 194 QuicDataStream* QuicServerSession::CreateOutgoingDataStream() {
 195   DLOG(ERROR) << "Server push not yet supported";
 196   return nullptr;
 197 }
 198
 199 QuicCryptoServerStream* QuicServerSession::GetCryptoStream() {
 200   return crypto_stream_.get();
 201 }
 202
 203 }  // namespace net