net/quic/quic_session.cc

   1 // Copyright (c) 2012 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_session.h"
   6
   7 #include "base/stl_util.h"
   8 #ifdef TEMP_INSTRUMENTATION_473893
   9 #include "base/debug/alias.h"
  10 #endif
  11 #include "net/quic/crypto/proof_verifier.h"
  12 #include "net/quic/quic_connection.h"
  13 #include "net/quic/quic_flags.h"
  14 #include "net/quic/quic_flow_controller.h"
  15 #include "net/ssl/ssl_info.h"
  16
  17 using base::StringPiece;
  18 using base::hash_map;
  19 using base::hash_set;
  20 using std::make_pair;
  21 using std::map;
  22 using std::max;
  23 using std::string;
  24 using std::vector;
  25
  26 namespace net {
  27
  28 #define ENDPOINT \
  29   (perspective() == Perspective::IS_SERVER ? "Server: " : " Client: ")
  30
  31 // We want to make sure we delete any closed streams in a safe manner.
  32 // To avoid deleting a stream in mid-operation, we have a simple shim between
  33 // us and the stream, so we can delete any streams when we return from
  34 // processing.
  35 //
  36 // We could just override the base methods, but this makes it easier to make
  37 // sure we don't miss any.
  38 class VisitorShim : public QuicConnectionVisitorInterface {
  39  public:
  40   explicit VisitorShim(QuicSession* session) : session_(session) {}
  41
  42   void OnStreamFrame(const QuicStreamFrame& frame) override {
  43     session_->OnStreamFrame(frame);
  44     session_->PostProcessAfterData();
  45   }
  46   void OnRstStream(const QuicRstStreamFrame& frame) override {
  47     session_->OnRstStream(frame);
  48     session_->PostProcessAfterData();
  49   }
  50
  51   void OnGoAway(const QuicGoAwayFrame& frame) override {
  52     session_->OnGoAway(frame);
  53     session_->PostProcessAfterData();
  54   }
  55
  56   void OnWindowUpdateFrame(const QuicWindowUpdateFrame& frame) override {
  57     session_->OnWindowUpdateFrame(frame);
  58     session_->PostProcessAfterData();
  59   }
  60
  61   void OnBlockedFrame(const QuicBlockedFrame& frame) override {
  62     session_->OnBlockedFrame(frame);
  63     session_->PostProcessAfterData();
  64   }
  65
  66   void OnCanWrite() override {
  67     session_->OnCanWrite();
  68     session_->PostProcessAfterData();
  69   }
  70
  71   void OnCongestionWindowChange(QuicTime now) override {
  72     session_->OnCongestionWindowChange(now);
  73   }
  74
  75   void OnSuccessfulVersionNegotiation(const QuicVersion& version) override {
  76     session_->OnSuccessfulVersionNegotiation(version);
  77   }
  78
  79   void OnConnectionClosed(QuicErrorCode error, bool from_peer) override {
  80     session_->OnConnectionClosed(error, from_peer);
  81     // The session will go away, so don't bother with cleanup.
  82   }
  83
  84   void OnWriteBlocked() override { session_->OnWriteBlocked(); }
  85
  86   bool WillingAndAbleToWrite() const override {
  87     return session_->WillingAndAbleToWrite();
  88   }
  89
  90   bool HasPendingHandshake() const override {
  91     return session_->HasPendingHandshake();
  92   }
  93
  94   bool HasOpenDynamicStreams() const override {
  95     return session_->HasOpenDynamicStreams();
  96   }
  97
  98  private:
  99   QuicSession* session_;
 100 };
 101
 102 QuicSession::QuicSession(QuicConnection* connection, const QuicConfig& config)
 103     : connection_(connection),
 104       visitor_shim_(new VisitorShim(this)),
 105       config_(config),
 106       max_open_streams_(config_.MaxStreamsPerConnection()),
 107       next_stream_id_(perspective() == Perspective::IS_SERVER ? 2 : 3),
 108       largest_peer_created_stream_id_(
 109           perspective() == Perspective::IS_SERVER ? 1 : 0),
 110       error_(QUIC_NO_ERROR),
 111       flow_controller_(connection_.get(),
 112                        0,
 113                        perspective(),
 114                        kMinimumFlowControlSendWindow,
 115                        config_.GetInitialSessionFlowControlWindowToSend(),
 116                        false),
 117       goaway_received_(false),
 118       goaway_sent_(false),
 119       has_pending_handshake_(false) {
 120 }
 121
 122 void QuicSession::Initialize() {
 123   connection_->set_visitor(visitor_shim_.get());
 124   connection_->SetFromConfig(config_);
 125
 126   DCHECK_EQ(kCryptoStreamId, GetCryptoStream()->id());
 127   static_stream_map_[kCryptoStreamId] = GetCryptoStream();
 128 }
 129
 130 QuicSession::~QuicSession() {
 131 #ifdef TEMP_INSTRUMENTATION_473893
 132   liveness_ = DEAD;
 133   stack_trace_ = base::debug::StackTrace();
 134
 135   // Probably not necessary, but just in case compiler tries to optimize out the
 136   // writes to liveness_ and stack_trace_.
 137   base::debug::Alias(&liveness_);
 138   base::debug::Alias(&stack_trace_);
 139 #endif
 140
 141   STLDeleteElements(&closed_streams_);
 142   STLDeleteValues(&dynamic_stream_map_);
 143
 144   DLOG_IF(WARNING,
 145           locally_closed_streams_highest_offset_.size() > max_open_streams_)
 146       << "Surprisingly high number of locally closed streams still waiting for "
 147          "final byte offset: " << locally_closed_streams_highest_offset_.size();
 148 }
 149
 150 void QuicSession::OnStreamFrame(const QuicStreamFrame& frame) {
 151   // TODO(rch) deal with the error case of stream id 0.
 152   QuicStreamId stream_id = frame.stream_id;
 153   ReliableQuicStream* stream = GetStream(stream_id);
 154   if (!stream) {
 155     // The stream no longer exists, but we may still be interested in the
 156     // final stream byte offset sent by the peer. A frame with a FIN can give
 157     // us this offset.
 158     if (frame.fin) {
 159       QuicStreamOffset final_byte_offset = frame.offset + frame.data.size();
 160       UpdateFlowControlOnFinalReceivedByteOffset(stream_id, final_byte_offset);
 161     }
 162     return;
 163   }
 164   stream->OnStreamFrame(frame);
 165 }
 166
 167 void QuicSession::OnRstStream(const QuicRstStreamFrame& frame) {
 168   if (ContainsKey(static_stream_map_, frame.stream_id)) {
 169     connection()->SendConnectionCloseWithDetails(
 170         QUIC_INVALID_STREAM_ID, "Attempt to reset a static stream");
 171     return;
 172   }
 173
 174   ReliableQuicStream* stream = GetDynamicStream(frame.stream_id);
 175   if (!stream) {
 176     // The RST frame contains the final byte offset for the stream: we can now
 177     // update the connection level flow controller if needed.
 178     UpdateFlowControlOnFinalReceivedByteOffset(frame.stream_id,
 179                                                frame.byte_offset);
 180     return;  // Errors are handled by GetStream.
 181   }
 182
 183   stream->OnStreamReset(frame);
 184 }
 185
 186 void QuicSession::OnGoAway(const QuicGoAwayFrame& frame) {
 187   DCHECK(frame.last_good_stream_id < next_stream_id_);
 188   goaway_received_ = true;
 189 }
 190
 191 void QuicSession::OnConnectionClosed(QuicErrorCode error, bool from_peer) {
 192   DCHECK(!connection_->connected());
 193   if (error_ == QUIC_NO_ERROR) {
 194     error_ = error;
 195   }
 196
 197   while (!dynamic_stream_map_.empty()) {
 198     StreamMap::iterator it = dynamic_stream_map_.begin();
 199     QuicStreamId id = it->first;
 200     it->second->OnConnectionClosed(error, from_peer);
 201     // The stream should call CloseStream as part of OnConnectionClosed.
 202     if (dynamic_stream_map_.find(id) != dynamic_stream_map_.end()) {
 203       LOG(DFATAL) << ENDPOINT
 204                   << "Stream failed to close under OnConnectionClosed";
 205       CloseStream(id);
 206     }
 207   }
 208 }
 209
 210 void QuicSession::OnSuccessfulVersionNegotiation(const QuicVersion& version) {
 211 }
 212
 213 void QuicSession::OnWindowUpdateFrame(const QuicWindowUpdateFrame& frame) {
 214   // Stream may be closed by the time we receive a WINDOW_UPDATE, so we can't
 215   // assume that it still exists.
 216   QuicStreamId stream_id = frame.stream_id;
 217   if (stream_id == kConnectionLevelId) {
 218     // This is a window update that applies to the connection, rather than an
 219     // individual stream.
 220     DVLOG(1) << ENDPOINT << "Received connection level flow control window "
 221                             "update with byte offset: "
 222              << frame.byte_offset;
 223     if (flow_controller_.UpdateSendWindowOffset(frame.byte_offset)) {
 224       // Connection level flow control window has increased, so blocked streams
 225       // can write again.
 226       // TODO(ianswett): I suspect this can be delayed until the packet
 227       // processing is complete.
 228       if (!FLAGS_quic_dont_write_when_flow_unblocked) {
 229         OnCanWrite();
 230       }
 231     }
 232     return;
 233   }
 234   ReliableQuicStream* stream = GetStream(stream_id);
 235   if (stream) {
 236     stream->OnWindowUpdateFrame(frame);
 237   }
 238 }
 239
 240 void QuicSession::OnBlockedFrame(const QuicBlockedFrame& frame) {
 241   // TODO(rjshade): Compare our flow control receive windows for specified
 242   //                streams: if we have a large window then maybe something
 243   //                had gone wrong with the flow control accounting.
 244   DVLOG(1) << ENDPOINT
 245            << "Received BLOCKED frame with stream id: " << frame.stream_id;
 246 }
 247
 248 void QuicSession::OnCanWrite() {
 249   // We limit the number of writes to the number of pending streams. If more
 250   // streams become pending, WillingAndAbleToWrite will be true, which will
 251   // cause the connection to request resumption before yielding to other
 252   // connections.
 253   size_t num_writes = write_blocked_streams_.NumBlockedStreams();
 254   if (flow_controller_.IsBlocked()) {
 255     // If we are connection level flow control blocked, then only allow the
 256     // crypto and headers streams to try writing as all other streams will be
 257     // blocked.
 258     num_writes = 0;
 259     if (write_blocked_streams_.crypto_stream_blocked()) {
 260       num_writes += 1;
 261     }
 262     if (write_blocked_streams_.headers_stream_blocked()) {
 263       num_writes += 1;
 264     }
 265   }
 266   if (num_writes == 0) {
 267     return;
 268   }
 269
 270   QuicConnection::ScopedPacketBundler ack_bundler(
 271       connection_.get(), QuicConnection::NO_ACK);
 272   for (size_t i = 0; i < num_writes; ++i) {
 273     if (!(write_blocked_streams_.HasWriteBlockedCryptoOrHeadersStream() ||
 274           write_blocked_streams_.HasWriteBlockedDataStreams())) {
 275       // Writing one stream removed another!? Something's broken.
 276       LOG(DFATAL) << "WriteBlockedStream is missing";
 277       connection_->CloseConnection(QUIC_INTERNAL_ERROR, false);
 278       return;
 279     }
 280     if (!connection_->CanWriteStreamData()) {
 281       return;
 282     }
 283     QuicStreamId stream_id = write_blocked_streams_.PopFront();
 284     if (stream_id == kCryptoStreamId) {
 285       has_pending_handshake_ = false;  // We just popped it.
 286     }
 287     ReliableQuicStream* stream = GetStream(stream_id);
 288     if (stream != nullptr && !stream->flow_controller()->IsBlocked()) {
 289       // If the stream can't write all bytes, it'll re-add itself to the blocked
 290       // list.
 291       stream->OnCanWrite();
 292     }
 293   }
 294 }
 295
 296 bool QuicSession::WillingAndAbleToWrite() const {
 297   // If the crypto or headers streams are blocked, we want to schedule a write -
 298   // they don't get blocked by connection level flow control. Otherwise only
 299   // schedule a write if we are not flow control blocked at the connection
 300   // level.
 301   return write_blocked_streams_.HasWriteBlockedCryptoOrHeadersStream() ||
 302          (!flow_controller_.IsBlocked() &&
 303           write_blocked_streams_.HasWriteBlockedDataStreams());
 304 }
 305
 306 bool QuicSession::HasPendingHandshake() const {
 307   return has_pending_handshake_;
 308 }
 309
 310 bool QuicSession::HasOpenDynamicStreams() const {
 311   return GetNumOpenStreams() > 0;
 312 }
 313
 314 QuicConsumedData QuicSession::WritevData(
 315     QuicStreamId id,
 316     const QuicIOVector& iov,
 317     QuicStreamOffset offset,
 318     bool fin,
 319     FecProtection fec_protection,
 320     QuicAckNotifier::DelegateInterface* ack_notifier_delegate) {
 321   return connection_->SendStreamData(id, iov, offset, fin, fec_protection,
 322                                      ack_notifier_delegate);
 323 }
 324
 325 void QuicSession::SendRstStream(QuicStreamId id,
 326                                 QuicRstStreamErrorCode error,
 327                                 QuicStreamOffset bytes_written) {
 328   if (ContainsKey(static_stream_map_, id)) {
 329     LOG(DFATAL) << "Cannot send RST for a static stream with ID " << id;
 330     return;
 331   }
 332
 333   if (connection()->connected()) {
 334     // Only send a RST_STREAM frame if still connected.
 335     connection_->SendRstStream(id, error, bytes_written);
 336   }
 337   CloseStreamInner(id, true);
 338 }
 339
 340 void QuicSession::SendGoAway(QuicErrorCode error_code, const string& reason) {
 341   if (goaway_sent_) {
 342     return;
 343   }
 344   goaway_sent_ = true;
 345   connection_->SendGoAway(error_code, largest_peer_created_stream_id_, reason);
 346 }
 347
 348 void QuicSession::CloseStream(QuicStreamId stream_id) {
 349   CloseStreamInner(stream_id, false);
 350 }
 351
 352 void QuicSession::CloseStreamInner(QuicStreamId stream_id,
 353                                    bool locally_reset) {
 354   DVLOG(1) << ENDPOINT << "Closing stream " << stream_id;
 355
 356   StreamMap::iterator it = dynamic_stream_map_.find(stream_id);
 357   if (it == dynamic_stream_map_.end()) {
 358     // When CloseStreamInner has been called recursively (via
 359     // ReliableQuicStream::OnClose), the stream will already have been deleted
 360     // from stream_map_, so return immediately.
 361     DVLOG(1) << ENDPOINT << "Stream is already closed: " << stream_id;
 362     return;
 363   }
 364   ReliableQuicStream* stream = it->second;
 365
 366   // Tell the stream that a RST has been sent.
 367   if (locally_reset) {
 368     stream->set_rst_sent(true);
 369   }
 370
 371   closed_streams_.push_back(it->second);
 372
 373   // If we haven't received a FIN or RST for this stream, we need to keep track
 374   // of the how many bytes the stream's flow controller believes it has
 375   // received, for accurate connection level flow control accounting.
 376   if (!stream->HasFinalReceivedByteOffset()) {
 377     locally_closed_streams_highest_offset_[stream_id] =
 378         stream->flow_controller()->highest_received_byte_offset();
 379   }
 380
 381   dynamic_stream_map_.erase(it);
 382   draining_streams_.erase(stream_id);
 383   stream->OnClose();
 384   // Decrease the number of streams being emulated when a new one is opened.
 385   connection_->SetNumOpenStreams(dynamic_stream_map_.size());
 386 }
 387
 388 void QuicSession::UpdateFlowControlOnFinalReceivedByteOffset(
 389     QuicStreamId stream_id, QuicStreamOffset final_byte_offset) {
 390   map<QuicStreamId, QuicStreamOffset>::iterator it =
 391       locally_closed_streams_highest_offset_.find(stream_id);
 392   if (it == locally_closed_streams_highest_offset_.end()) {
 393     return;
 394   }
 395
 396   DVLOG(1) << ENDPOINT << "Received final byte offset " << final_byte_offset
 397            << " for stream " << stream_id;
 398   QuicByteCount offset_diff = final_byte_offset - it->second;
 399   if (flow_controller_.UpdateHighestReceivedOffset(
 400           flow_controller_.highest_received_byte_offset() + offset_diff)) {
 401     // If the final offset violates flow control, close the connection now.
 402     if (flow_controller_.FlowControlViolation()) {
 403       connection_->SendConnectionClose(
 404           QUIC_FLOW_CONTROL_RECEIVED_TOO_MUCH_DATA);
 405       return;
 406     }
 407   }
 408
 409   flow_controller_.AddBytesConsumed(offset_diff);
 410   locally_closed_streams_highest_offset_.erase(it);
 411 }
 412
 413 bool QuicSession::IsEncryptionEstablished() {
 414   return GetCryptoStream()->encryption_established();
 415 }
 416
 417 bool QuicSession::IsCryptoHandshakeConfirmed() {
 418   return GetCryptoStream()->handshake_confirmed();
 419 }
 420
 421 void QuicSession::OnConfigNegotiated() {
 422   connection_->SetFromConfig(config_);
 423
 424   uint32 max_streams = config_.MaxStreamsPerConnection();
 425   if (perspective() == Perspective::IS_SERVER) {
 426     // A server should accept a small number of additional streams beyond the
 427     // limit sent to the client. This helps avoid early connection termination
 428     // when FIN/RSTs for old streams are lost or arrive out of order.
 429     // Use a minimum number of additional streams, or a percentage increase,
 430     // whichever is larger.
 431     max_streams =
 432         max(max_streams + kMaxStreamsMinimumIncrement,
 433             static_cast<uint32>(max_streams * kMaxStreamsMultiplier));
 434
 435     if (config_.HasReceivedConnectionOptions()) {
 436       if (ContainsQuicTag(config_.ReceivedConnectionOptions(), kAFCW)) {
 437         EnableAutoTuneReceiveWindow();
 438       }
 439       // The following variations change the initial receive flow control window
 440       // size for streams.  For simplicity reasons, do not try to effect
 441       // existing streams but only future ones.
 442       if (ContainsQuicTag(config_.ReceivedConnectionOptions(), kIFW5)) {
 443         config_.SetInitialStreamFlowControlWindowToSend(32 * 1024);
 444       }
 445       if (ContainsQuicTag(config_.ReceivedConnectionOptions(), kIFW6)) {
 446         config_.SetInitialStreamFlowControlWindowToSend(64 * 1024);
 447       }
 448       if (ContainsQuicTag(config_.ReceivedConnectionOptions(), kIFW7)) {
 449         config_.SetInitialStreamFlowControlWindowToSend(128 * 1024);
 450       }
 451     }
 452   }
 453   set_max_open_streams(max_streams);
 454
 455   if (config_.HasReceivedInitialStreamFlowControlWindowBytes()) {
 456     // Streams which were created before the SHLO was received (0-RTT
 457     // requests) are now informed of the peer's initial flow control window.
 458     OnNewStreamFlowControlWindow(
 459         config_.ReceivedInitialStreamFlowControlWindowBytes());
 460   }
 461   if (config_.HasReceivedInitialSessionFlowControlWindowBytes()) {
 462     OnNewSessionFlowControlWindow(
 463         config_.ReceivedInitialSessionFlowControlWindowBytes());
 464   }
 465 }
 466
 467 void QuicSession::EnableAutoTuneReceiveWindow() {
 468   flow_controller_.set_auto_tune_receive_window(true);
 469   // Inform all existing streams about the new window.
 470   for (auto const& kv : static_stream_map_) {
 471     kv.second->flow_controller()->set_auto_tune_receive_window(true);
 472   }
 473   for (auto const& kv : dynamic_stream_map_) {
 474     kv.second->flow_controller()->set_auto_tune_receive_window(true);
 475   }
 476 }
 477
 478 void QuicSession::OnNewStreamFlowControlWindow(QuicStreamOffset new_window) {
 479   if (new_window < kMinimumFlowControlSendWindow) {
 480     LOG(ERROR) << "Peer sent us an invalid stream flow control send window: "
 481                << new_window
 482                << ", below default: " << kMinimumFlowControlSendWindow;
 483     if (connection_->connected()) {
 484       connection_->SendConnectionClose(QUIC_FLOW_CONTROL_INVALID_WINDOW);
 485     }
 486     return;
 487   }
 488
 489   // Inform all existing streams about the new window.
 490   for (auto const& kv : static_stream_map_) {
 491     kv.second->UpdateSendWindowOffset(new_window);
 492   }
 493   for (auto const& kv : dynamic_stream_map_) {
 494     kv.second->UpdateSendWindowOffset(new_window);
 495   }
 496 }
 497
 498 void QuicSession::OnNewSessionFlowControlWindow(QuicStreamOffset new_window) {
 499   if (new_window < kMinimumFlowControlSendWindow) {
 500     LOG(ERROR) << "Peer sent us an invalid session flow control send window: "
 501                << new_window
 502                << ", below default: " << kMinimumFlowControlSendWindow;
 503     if (connection_->connected()) {
 504       connection_->SendConnectionClose(QUIC_FLOW_CONTROL_INVALID_WINDOW);
 505     }
 506     return;
 507   }
 508
 509   flow_controller_.UpdateSendWindowOffset(new_window);
 510 }
 511
 512 void QuicSession::OnCryptoHandshakeEvent(CryptoHandshakeEvent event) {
 513   switch (event) {
 514     // TODO(satyamshekhar): Move the logic of setting the encrypter/decrypter
 515     // to QuicSession since it is the glue.
 516     case ENCRYPTION_FIRST_ESTABLISHED:
 517       break;
 518
 519     case ENCRYPTION_REESTABLISHED:
 520       // Retransmit originally packets that were sent, since they can't be
 521       // decrypted by the peer.
 522       connection_->RetransmitUnackedPackets(ALL_INITIAL_RETRANSMISSION);
 523       break;
 524
 525     case HANDSHAKE_CONFIRMED:
 526       LOG_IF(DFATAL, !config_.negotiated()) << ENDPOINT
 527           << "Handshake confirmed without parameter negotiation.";
 528       // Discard originally encrypted packets, since they can't be decrypted by
 529       // the peer.
 530       connection_->NeuterUnencryptedPackets();
 531       break;
 532
 533     default:
 534       LOG(ERROR) << ENDPOINT << "Got unknown handshake event: " << event;
 535   }
 536 }
 537
 538 void QuicSession::OnCryptoHandshakeMessageSent(
 539     const CryptoHandshakeMessage& message) {
 540 }
 541
 542 void QuicSession::OnCryptoHandshakeMessageReceived(
 543     const CryptoHandshakeMessage& message) {
 544 }
 545
 546 QuicConfig* QuicSession::config() {
 547   return &config_;
 548 }
 549
 550 void QuicSession::ActivateStream(ReliableQuicStream* stream) {
 551   DVLOG(1) << ENDPOINT << "num_streams: " << dynamic_stream_map_.size()
 552            << ". activating " << stream->id();
 553   DCHECK(!ContainsKey(dynamic_stream_map_, stream->id()));
 554   DCHECK(!ContainsKey(static_stream_map_, stream->id()));
 555   dynamic_stream_map_[stream->id()] = stream;
 556   // Increase the number of streams being emulated when a new one is opened.
 557   connection_->SetNumOpenStreams(dynamic_stream_map_.size());
 558 }
 559
 560 QuicStreamId QuicSession::GetNextStreamId() {
 561   QuicStreamId id = next_stream_id_;
 562   next_stream_id_ += 2;
 563   return id;
 564 }
 565
 566 ReliableQuicStream* QuicSession::GetStream(const QuicStreamId stream_id) {
 567   StreamMap::iterator it = static_stream_map_.find(stream_id);
 568   if (it != static_stream_map_.end()) {
 569     return it->second;
 570   }
 571   return GetDynamicStream(stream_id);
 572 }
 573
 574 void QuicSession::StreamDraining(QuicStreamId stream_id) {
 575   DCHECK(ContainsKey(dynamic_stream_map_, stream_id));
 576   if (!ContainsKey(draining_streams_, stream_id)) {
 577     draining_streams_.insert(stream_id);
 578   }
 579 }
 580
 581 ReliableQuicStream* QuicSession::GetDynamicStream(
 582     const QuicStreamId stream_id) {
 583   if (static_stream_map_.find(stream_id) != static_stream_map_.end()) {
 584     DLOG(FATAL) << "Attempt to call GetDynamicStream for a static stream";
 585     return nullptr;
 586   }
 587
 588   StreamMap::iterator it = dynamic_stream_map_.find(stream_id);
 589   if (it != dynamic_stream_map_.end()) {
 590     return it->second;
 591   }
 592
 593   if (IsClosedStream(stream_id)) {
 594     return nullptr;
 595   }
 596
 597   if (stream_id % 2 == next_stream_id_ % 2) {
 598     // We've received a frame for a locally-created stream that is not
 599     // currently active.  This is an error.
 600     if (connection()->connected()) {
 601       connection()->SendConnectionClose(QUIC_PACKET_FOR_NONEXISTENT_STREAM);
 602     }
 603     return nullptr;
 604   }
 605
 606   return GetIncomingDynamicStream(stream_id);
 607 }
 608
 609 ReliableQuicStream* QuicSession::GetIncomingDynamicStream(
 610     QuicStreamId stream_id) {
 611   if (IsClosedStream(stream_id)) {
 612     return nullptr;
 613   }
 614   implicitly_created_streams_.erase(stream_id);
 615   if (stream_id > largest_peer_created_stream_id_) {
 616     if (FLAGS_exact_stream_id_delta) {
 617       // Check if the number of streams that will be created (including
 618       // implicitly open streams) would cause the number of open streams to
 619       // exceed the limit.  Note that the peer can create only
 620       // alternately-numbered streams.
 621       if ((stream_id - largest_peer_created_stream_id_) / 2 +
 622               GetNumOpenStreams() >
 623           get_max_open_streams()) {
 624         DVLOG(1) << "Failed to create a new incoming stream with id:"
 625                  << stream_id << ".  Already " << GetNumOpenStreams()
 626                  << " streams open, would exceed max " << get_max_open_streams()
 627                  << ".";
 628         // We may already have sent a connection close due to multiple reset
 629         // streams in the same packet.
 630         if (connection()->connected()) {
 631           connection()->SendConnectionClose(QUIC_TOO_MANY_OPEN_STREAMS);
 632         }
 633         return nullptr;
 634       }
 635     } else {
 636       // Limit on the delta between stream IDs.
 637       const QuicStreamId kMaxStreamIdDelta = 200;
 638       if (stream_id - largest_peer_created_stream_id_ > kMaxStreamIdDelta) {
 639         // We may already have sent a connection close due to multiple reset
 640         // streams in the same packet.
 641         if (connection()->connected()) {
 642           LOG(ERROR) << "Trying to get stream: " << stream_id
 643                      << ", largest peer created stream: "
 644                      << largest_peer_created_stream_id_
 645                      << ", max delta: " << kMaxStreamIdDelta;
 646           connection()->SendConnectionClose(QUIC_INVALID_STREAM_ID);
 647         }
 648         return nullptr;
 649       }
 650     }
 651     for (QuicStreamId id = largest_peer_created_stream_id_ + 2;
 652          id < stream_id;
 653          id += 2) {
 654       implicitly_created_streams_.insert(id);
 655     }
 656     largest_peer_created_stream_id_ = stream_id;
 657   }
 658   ReliableQuicStream* stream = CreateIncomingDynamicStream(stream_id);
 659   if (stream == nullptr) {
 660     return nullptr;
 661   }
 662   ActivateStream(stream);
 663   return stream;
 664 }
 665
 666 void QuicSession::set_max_open_streams(size_t max_open_streams) {
 667   DVLOG(1) << "Setting max_open_streams_ to " << max_open_streams;
 668   max_open_streams_ = max_open_streams;
 669 }
 670
 671 bool QuicSession::IsClosedStream(QuicStreamId id) {
 672   DCHECK_NE(0u, id);
 673   if (ContainsKey(static_stream_map_, id) ||
 674       ContainsKey(dynamic_stream_map_, id)) {
 675     // Stream is active
 676     return false;
 677   }
 678   if (id % 2 == next_stream_id_ % 2) {
 679     // Locally created streams are strictly in-order.  If the id is in the
 680     // range of created streams and it's not active, it must have been closed.
 681     return id < next_stream_id_;
 682   }
 683   // For peer created streams, we also need to consider implicitly created
 684   // streams.
 685   return id <= largest_peer_created_stream_id_ &&
 686       !ContainsKey(implicitly_created_streams_, id);
 687 }
 688
 689 size_t QuicSession::GetNumOpenStreams() const {
 690   return dynamic_stream_map_.size() + implicitly_created_streams_.size() -
 691          draining_streams_.size();
 692 }
 693
 694 void QuicSession::MarkConnectionLevelWriteBlocked(QuicStreamId id,
 695                                                   QuicPriority priority) {
 696 #ifndef NDEBUG
 697   ReliableQuicStream* stream = GetStream(id);
 698   if (stream != nullptr) {
 699     LOG_IF(DFATAL, priority != stream->EffectivePriority())
 700         << ENDPOINT << "Stream " << id
 701         << "Priorities do not match.  Got: " << priority
 702         << " Expected: " << stream->EffectivePriority();
 703   } else {
 704     LOG(DFATAL) << "Marking unknown stream " << id << " blocked.";
 705   }
 706 #endif
 707
 708   if (id == kCryptoStreamId) {
 709     DCHECK(!has_pending_handshake_);
 710     has_pending_handshake_ = true;
 711     // TODO(jar): Be sure to use the highest priority for the crypto stream,
 712     // perhaps by adding a "special" priority for it that is higher than
 713     // kHighestPriority.
 714     priority = kHighestPriority;
 715   }
 716   write_blocked_streams_.PushBack(id, priority);
 717 }
 718
 719 bool QuicSession::HasDataToWrite() const {
 720   return write_blocked_streams_.HasWriteBlockedCryptoOrHeadersStream() ||
 721          write_blocked_streams_.HasWriteBlockedDataStreams() ||
 722          connection_->HasQueuedData();
 723 }
 724
 725 void QuicSession::PostProcessAfterData() {
 726   STLDeleteElements(&closed_streams_);
 727
 728   if (connection()->connected() &&
 729       locally_closed_streams_highest_offset_.size() > max_open_streams_) {
 730     // A buggy client may fail to send FIN/RSTs. Don't tolerate this.
 731     connection_->SendConnectionClose(QUIC_TOO_MANY_UNFINISHED_STREAMS);
 732   }
 733 }
 734
 735 bool QuicSession::IsConnectionFlowControlBlocked() const {
 736   return flow_controller_.IsBlocked();
 737 }
 738
 739 bool QuicSession::IsStreamFlowControlBlocked() {
 740   for (auto const& kv : static_stream_map_) {
 741     if (kv.second->flow_controller()->IsBlocked()) {
 742       return true;
 743     }
 744   }
 745   for (auto const& kv : dynamic_stream_map_) {
 746     if (kv.second->flow_controller()->IsBlocked()) {
 747       return true;
 748     }
 749   }
 750   return false;
 751 }
 752
 753 void QuicSession::CrashIfInvalid() const {
 754 #ifdef TEMP_INSTRUMENTATION_473893
 755   Liveness liveness = liveness_;
 756
 757   if (liveness == ALIVE)
 758     return;
 759
 760   // Copy relevant variables onto the stack to guarantee they will be available
 761   // in minidumps, and then crash.
 762   base::debug::StackTrace stack_trace = stack_trace_;
 763
 764   base::debug::Alias(&liveness);
 765   base::debug::Alias(&stack_trace);
 766
 767   CHECK_EQ(ALIVE, liveness);
 768 #endif
 769 }
 770
 771 }  // namespace net