| // 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/third_party/quiche/src/quic/core/quic_session.h" | 
 |  | 
 | #include <cstdint> | 
 | #include <string> | 
 | #include <utility> | 
 |  | 
 | #include "net/third_party/quiche/src/quic/core/quic_connection.h" | 
 | #include "net/third_party/quiche/src/quic/core/quic_flow_controller.h" | 
 | #include "net/third_party/quiche/src/quic/core/quic_types.h" | 
 | #include "net/third_party/quiche/src/quic/core/quic_utils.h" | 
 | #include "net/third_party/quiche/src/quic/core/quic_versions.h" | 
 | #include "net/third_party/quiche/src/quic/platform/api/quic_bug_tracker.h" | 
 | #include "net/third_party/quiche/src/quic/platform/api/quic_flag_utils.h" | 
 | #include "net/third_party/quiche/src/quic/platform/api/quic_flags.h" | 
 | #include "net/third_party/quiche/src/quic/platform/api/quic_logging.h" | 
 | #include "net/third_party/quiche/src/quic/platform/api/quic_map_util.h" | 
 | #include "net/third_party/quiche/src/quic/platform/api/quic_server_stats.h" | 
 | #include "net/third_party/quiche/src/quic/platform/api/quic_stack_trace.h" | 
 | #include "net/third_party/quiche/src/quic/platform/api/quic_str_cat.h" | 
 |  | 
 | using spdy::SpdyPriority; | 
 |  | 
 | namespace quic { | 
 |  | 
 | namespace { | 
 |  | 
 | class ClosedStreamsCleanUpDelegate : public QuicAlarm::Delegate { | 
 |  public: | 
 |   explicit ClosedStreamsCleanUpDelegate(QuicSession* session) | 
 |       : session_(session) {} | 
 |   ClosedStreamsCleanUpDelegate(const ClosedStreamsCleanUpDelegate&) = delete; | 
 |   ClosedStreamsCleanUpDelegate& operator=(const ClosedStreamsCleanUpDelegate&) = | 
 |       delete; | 
 |  | 
 |   void OnAlarm() override { session_->CleanUpClosedStreams(); } | 
 |  | 
 |  private: | 
 |   QuicSession* session_; | 
 | }; | 
 |  | 
 | }  // namespace | 
 |  | 
 | #define ENDPOINT \ | 
 |   (perspective() == Perspective::IS_SERVER ? "Server: " : "Client: ") | 
 |  | 
 | QuicSession::QuicSession(QuicConnection* connection, | 
 |                          Visitor* owner, | 
 |                          const QuicConfig& config, | 
 |                          const ParsedQuicVersionVector& supported_versions) | 
 |     : connection_(connection), | 
 |       visitor_(owner), | 
 |       write_blocked_streams_(connection->transport_version()), | 
 |       config_(config), | 
 |       stream_id_manager_(this, | 
 |                          kDefaultMaxStreamsPerConnection, | 
 |                          config_.GetMaxIncomingBidirectionalStreamsToSend()), | 
 |       v99_streamid_manager_( | 
 |           this, | 
 |           kDefaultMaxStreamsPerConnection, | 
 |           kDefaultMaxStreamsPerConnection, | 
 |           config_.GetMaxIncomingBidirectionalStreamsToSend(), | 
 |           config_.GetMaxIncomingUnidirectionalStreamsToSend()), | 
 |       num_dynamic_incoming_streams_(0), | 
 |       num_draining_incoming_streams_(0), | 
 |       num_outgoing_static_streams_(0), | 
 |       num_incoming_static_streams_(0), | 
 |       num_locally_closed_incoming_streams_highest_offset_(0), | 
 |       error_(QUIC_NO_ERROR), | 
 |       flow_controller_( | 
 |           this, | 
 |           QuicUtils::GetInvalidStreamId(connection->transport_version()), | 
 |           /*is_connection_flow_controller*/ true, | 
 |           connection->version().AllowsLowFlowControlLimits() | 
 |               ? 0 | 
 |               : kMinimumFlowControlSendWindow, | 
 |           config_.GetInitialSessionFlowControlWindowToSend(), | 
 |           kSessionReceiveWindowLimit, | 
 |           perspective() == Perspective::IS_SERVER, | 
 |           nullptr), | 
 |       currently_writing_stream_id_(0), | 
 |       is_handshake_confirmed_(false), | 
 |       goaway_sent_(false), | 
 |       goaway_received_(false), | 
 |       control_frame_manager_(this), | 
 |       last_message_id_(0), | 
 |       closed_streams_clean_up_alarm_(nullptr), | 
 |       supported_versions_(supported_versions) { | 
 |   closed_streams_clean_up_alarm_ = | 
 |       QuicWrapUnique<QuicAlarm>(connection_->alarm_factory()->CreateAlarm( | 
 |           new ClosedStreamsCleanUpDelegate(this))); | 
 | } | 
 |  | 
 | void QuicSession::Initialize() { | 
 |   connection_->set_visitor(this); | 
 |   connection_->SetSessionNotifier(this); | 
 |   connection_->SetDataProducer(this); | 
 |   connection_->SetFromConfig(config_); | 
 |  | 
 |   if (QuicVersionUsesCryptoFrames(connection_->transport_version())) { | 
 |     return; | 
 |   } | 
 |  | 
 |   DCHECK_EQ(QuicUtils::GetCryptoStreamId(connection_->transport_version()), | 
 |             GetMutableCryptoStream()->id()); | 
 |  | 
 |   QuicStreamId id = | 
 |       QuicUtils::GetCryptoStreamId(connection_->transport_version()); | 
 |   if (VersionHasIetfQuicFrames(connection_->transport_version())) { | 
 |     v99_streamid_manager_.RegisterStaticStream(id, false); | 
 |   } | 
 | } | 
 |  | 
 | QuicSession::~QuicSession() { | 
 |   QUIC_LOG_IF(WARNING, !zombie_streams_.empty()) << "Still have zombie streams"; | 
 | } | 
 |  | 
 | void QuicSession::RegisterStaticStream(std::unique_ptr<QuicStream> stream, | 
 |                                        bool stream_already_counted) { | 
 |   DCHECK(stream->is_static()); | 
 |   QuicStreamId stream_id = stream->id(); | 
 |   stream_map_[stream_id] = std::move(stream); | 
 |   if (VersionHasIetfQuicFrames(connection_->transport_version())) { | 
 |     v99_streamid_manager_.RegisterStaticStream(stream_id, | 
 |                                                stream_already_counted); | 
 |   } | 
 |   if (IsIncomingStream(stream_id)) { | 
 |     ++num_incoming_static_streams_; | 
 |   } else { | 
 |     ++num_outgoing_static_streams_; | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::PendingStreamOnStreamFrame(const QuicStreamFrame& frame) { | 
 |   DCHECK(VersionHasStreamType(connection()->transport_version())); | 
 |   QuicStreamId stream_id = frame.stream_id; | 
 |  | 
 |   PendingStream* pending = GetOrCreatePendingStream(stream_id); | 
 |  | 
 |   if (!pending) { | 
 |     if (frame.fin) { | 
 |       QuicStreamOffset final_byte_offset = frame.offset + frame.data_length; | 
 |       OnFinalByteOffsetReceived(stream_id, final_byte_offset); | 
 |     } | 
 |     return; | 
 |   } | 
 |  | 
 |   pending->OnStreamFrame(frame); | 
 |   if (!connection()->connected()) { | 
 |     return; | 
 |   } | 
 |   if (ProcessPendingStream(pending)) { | 
 |     // The pending stream should now be in the scope of normal streams. | 
 |     DCHECK(IsClosedStream(stream_id) || IsOpenStream(stream_id)) | 
 |         << "Stream " << stream_id << " not created"; | 
 |     pending_stream_map_.erase(stream_id); | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::OnStreamFrame(const QuicStreamFrame& frame) { | 
 |   // TODO(rch) deal with the error case of stream id 0. | 
 |   QuicStreamId stream_id = frame.stream_id; | 
 |   if (stream_id == | 
 |       QuicUtils::GetInvalidStreamId(connection()->transport_version())) { | 
 |     connection()->CloseConnection( | 
 |         QUIC_INVALID_STREAM_ID, "Received data for an invalid stream", | 
 |         ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     return; | 
 |   } | 
 |  | 
 |   if (UsesPendingStreams() && | 
 |       QuicUtils::GetStreamType(stream_id, perspective(), | 
 |                                IsIncomingStream(stream_id)) == | 
 |           READ_UNIDIRECTIONAL && | 
 |       stream_map_.find(stream_id) == stream_map_.end()) { | 
 |     PendingStreamOnStreamFrame(frame); | 
 |     return; | 
 |   } | 
 |  | 
 |   QuicStream* stream = GetOrCreateStream(stream_id); | 
 |  | 
 |   if (!stream) { | 
 |     // The stream no longer exists, but we may still be interested in the | 
 |     // final stream byte offset sent by the peer. A frame with a FIN can give | 
 |     // us this offset. | 
 |     if (frame.fin) { | 
 |       QuicStreamOffset final_byte_offset = frame.offset + frame.data_length; | 
 |       OnFinalByteOffsetReceived(stream_id, final_byte_offset); | 
 |     } | 
 |     return; | 
 |   } | 
 |   if (frame.fin && stream->is_static()) { | 
 |     connection()->CloseConnection( | 
 |         QUIC_INVALID_STREAM_ID, "Attempt to close a static stream", | 
 |         ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     return; | 
 |   } | 
 |   stream->OnStreamFrame(frame); | 
 | } | 
 |  | 
 | void QuicSession::OnCryptoFrame(const QuicCryptoFrame& frame) { | 
 |   GetMutableCryptoStream()->OnCryptoFrame(frame); | 
 | } | 
 |  | 
 | bool QuicSession::OnStopSendingFrame(const QuicStopSendingFrame& frame) { | 
 |   // We are not version 99. In theory, if not in version 99 then the framer | 
 |   // could not call OnStopSending... This is just a check that is good when | 
 |   // both a new protocol and a new implementation of that protocol are both | 
 |   // being developed. | 
 |   DCHECK(VersionHasIetfQuicFrames(connection_->transport_version())); | 
 |  | 
 |   QuicStreamId stream_id = frame.stream_id; | 
 |   // If Stream ID is invalid then close the connection. | 
 |   if (stream_id == | 
 |       QuicUtils::GetInvalidStreamId(connection()->transport_version())) { | 
 |     QUIC_DVLOG(1) << ENDPOINT | 
 |                   << "Received STOP_SENDING with invalid stream_id: " | 
 |                   << stream_id << " Closing connection"; | 
 |     connection()->CloseConnection( | 
 |         QUIC_INVALID_STREAM_ID, "Received STOP_SENDING for an invalid stream", | 
 |         ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     return false; | 
 |   } | 
 |  | 
 |   // Ignore STOP_SENDING for static streams. | 
 |   // TODO(fkastenholz): IETF Quic does not have static streams and does not | 
 |   // make exceptions for them with respect to processing things like | 
 |   // STOP_SENDING. | 
 |   if (QuicUtils::IsCryptoStreamId(connection_->transport_version(), | 
 |                                   stream_id)) { | 
 |     QUIC_DVLOG(1) << ENDPOINT | 
 |                   << "Received STOP_SENDING for a static stream, id: " | 
 |                   << stream_id << " Closing connection"; | 
 |     connection()->CloseConnection( | 
 |         QUIC_INVALID_STREAM_ID, "Received STOP_SENDING for a static stream", | 
 |         ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (visitor_) { | 
 |     visitor_->OnStopSendingReceived(frame); | 
 |   } | 
 |  | 
 |   // If stream is closed, ignore the frame | 
 |   if (IsClosedStream(stream_id)) { | 
 |     QUIC_DVLOG(1) | 
 |         << ENDPOINT | 
 |         << "Received STOP_SENDING for closed or non-existent stream, id: " | 
 |         << stream_id << " Ignoring."; | 
 |     return true;  // Continue processing the packet. | 
 |   } | 
 |   // If stream is non-existent, close the connection | 
 |   StreamMap::iterator it = stream_map_.find(stream_id); | 
 |   if (it == stream_map_.end()) { | 
 |     QUIC_DVLOG(1) << ENDPOINT | 
 |                   << "Received STOP_SENDING for non-existent stream, id: " | 
 |                   << stream_id << " Closing connection"; | 
 |     connection()->CloseConnection( | 
 |         IETF_QUIC_PROTOCOL_VIOLATION, | 
 |         "Received STOP_SENDING for a non-existent stream", | 
 |         ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     return false; | 
 |   } | 
 |  | 
 |   // Get the QuicStream for this stream. Ignore the STOP_SENDING | 
 |   // if the QuicStream pointer is NULL | 
 |   // QUESTION(fkastenholz): IS THIS THE RIGHT THING TO DO? (that is, this would | 
 |   // happen IFF there was an entry in the map, but the pointer is null. sounds | 
 |   // more like a deep programming error rather than a simple protocol problem). | 
 |   QuicStream* stream = it->second.get(); | 
 |   if (stream == nullptr) { | 
 |     QUIC_BUG << ENDPOINT | 
 |              << "Received STOP_SENDING for NULL QuicStream, stream_id: " | 
 |              << stream_id << ". Ignoring."; | 
 |     return true; | 
 |   } | 
 |  | 
 |   if (stream->is_static()) { | 
 |     QUIC_DVLOG(1) << ENDPOINT | 
 |                   << "Received STOP_SENDING for a static stream, id: " | 
 |                   << stream_id << " Closing connection"; | 
 |     connection()->CloseConnection( | 
 |         QUIC_INVALID_STREAM_ID, "Received STOP_SENDING for a static stream", | 
 |         ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     return false; | 
 |   } | 
 |  | 
 |   stream->OnStopSending(frame.application_error_code); | 
 |  | 
 |   stream->set_stream_error( | 
 |       static_cast<QuicRstStreamErrorCode>(frame.application_error_code)); | 
 |   SendRstStreamInner( | 
 |       stream->id(), | 
 |       static_cast<quic::QuicRstStreamErrorCode>(frame.application_error_code), | 
 |       stream->stream_bytes_written(), | 
 |       /*close_write_side_only=*/true); | 
 |  | 
 |   return true; | 
 | } | 
 |  | 
 | void QuicSession::PendingStreamOnRstStream(const QuicRstStreamFrame& frame) { | 
 |   DCHECK(VersionHasStreamType(connection()->transport_version())); | 
 |   QuicStreamId stream_id = frame.stream_id; | 
 |  | 
 |   PendingStream* pending = GetOrCreatePendingStream(stream_id); | 
 |  | 
 |   if (!pending) { | 
 |     HandleRstOnValidNonexistentStream(frame); | 
 |     return; | 
 |   } | 
 |  | 
 |   pending->OnRstStreamFrame(frame); | 
 |   ClosePendingStream(stream_id); | 
 | } | 
 |  | 
 | void QuicSession::OnRstStream(const QuicRstStreamFrame& frame) { | 
 |   QuicStreamId stream_id = frame.stream_id; | 
 |   if (stream_id == | 
 |       QuicUtils::GetInvalidStreamId(connection()->transport_version())) { | 
 |     connection()->CloseConnection( | 
 |         QUIC_INVALID_STREAM_ID, "Received data for an invalid stream", | 
 |         ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     return; | 
 |   } | 
 |  | 
 |   if (visitor_) { | 
 |     visitor_->OnRstStreamReceived(frame); | 
 |   } | 
 |  | 
 |   if (UsesPendingStreams() && | 
 |       QuicUtils::GetStreamType(stream_id, perspective(), | 
 |                                IsIncomingStream(stream_id)) == | 
 |           READ_UNIDIRECTIONAL && | 
 |       stream_map_.find(stream_id) == stream_map_.end()) { | 
 |     PendingStreamOnRstStream(frame); | 
 |     return; | 
 |   } | 
 |  | 
 |   QuicStream* stream = GetOrCreateStream(stream_id); | 
 |  | 
 |   if (!stream) { | 
 |     HandleRstOnValidNonexistentStream(frame); | 
 |     return;  // Errors are handled by GetOrCreateStream. | 
 |   } | 
 |   if (stream->is_static()) { | 
 |     connection()->CloseConnection( | 
 |         QUIC_INVALID_STREAM_ID, "Attempt to reset a static stream", | 
 |         ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     return; | 
 |   } | 
 |   stream->OnStreamReset(frame); | 
 | } | 
 |  | 
 | void QuicSession::OnGoAway(const QuicGoAwayFrame& /*frame*/) { | 
 |   goaway_received_ = true; | 
 | } | 
 |  | 
 | void QuicSession::OnMessageReceived(QuicStringPiece message) { | 
 |   QUIC_DVLOG(1) << ENDPOINT << "Received message, length: " << message.length() | 
 |                 << ", " << message; | 
 | } | 
 |  | 
 | // static | 
 | void QuicSession::RecordConnectionCloseAtServer(QuicErrorCode error, | 
 |                                                 ConnectionCloseSource source) { | 
 |   if (error != QUIC_NO_ERROR) { | 
 |     if (source == ConnectionCloseSource::FROM_SELF) { | 
 |       QUIC_SERVER_HISTOGRAM_ENUM( | 
 |           "quic_server_connection_close_errors", error, QUIC_LAST_ERROR, | 
 |           "QuicErrorCode for server-closed connections."); | 
 |     } else { | 
 |       QUIC_SERVER_HISTOGRAM_ENUM( | 
 |           "quic_client_connection_close_errors", error, QUIC_LAST_ERROR, | 
 |           "QuicErrorCode for client-closed connections."); | 
 |     } | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::OnConnectionClosed(const QuicConnectionCloseFrame& frame, | 
 |                                      ConnectionCloseSource source) { | 
 |   DCHECK(!connection_->connected()); | 
 |   if (perspective() == Perspective::IS_SERVER) { | 
 |     RecordConnectionCloseAtServer(frame.quic_error_code, source); | 
 |   } | 
 |  | 
 |   if (error_ == QUIC_NO_ERROR) { | 
 |     error_ = frame.quic_error_code; | 
 |   } | 
 |  | 
 |   // Copy all non static streams in a new map for the ease of deleting. | 
 |   QuicSmallMap<QuicStreamId, QuicStream*, 10> non_static_streams; | 
 |   for (const auto& it : stream_map_) { | 
 |     if (!it.second->is_static()) { | 
 |       non_static_streams[it.first] = it.second.get(); | 
 |     } | 
 |   } | 
 |   for (const auto& it : non_static_streams) { | 
 |     QuicStreamId id = it.first; | 
 |     it.second->OnConnectionClosed(frame.quic_error_code, source); | 
 |     if (stream_map_.find(id) != stream_map_.end()) { | 
 |       QUIC_BUG << ENDPOINT << "Stream " << id | 
 |                << " failed to close under OnConnectionClosed"; | 
 |       CloseStream(id); | 
 |     } | 
 |   } | 
 |  | 
 |   // Cleanup zombie stream map on connection close. | 
 |   while (!zombie_streams_.empty()) { | 
 |     ZombieStreamMap::iterator it = zombie_streams_.begin(); | 
 |     closed_streams_.push_back(std::move(it->second)); | 
 |     zombie_streams_.erase(it); | 
 |   } | 
 |  | 
 |   closed_streams_clean_up_alarm_->Cancel(); | 
 |  | 
 |   if (visitor_) { | 
 |     visitor_->OnConnectionClosed(connection_->connection_id(), | 
 |                                  frame.quic_error_code, frame.error_details, | 
 |                                  source); | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::OnWriteBlocked() { | 
 |   if (!connection_->connected()) { | 
 |     return; | 
 |   } | 
 |   if (visitor_) { | 
 |     visitor_->OnWriteBlocked(connection_); | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::OnSuccessfulVersionNegotiation( | 
 |     const ParsedQuicVersion& version) { | 
 |   GetMutableCryptoStream()->OnSuccessfulVersionNegotiation(version); | 
 | } | 
 |  | 
 | void QuicSession::OnConnectivityProbeReceived( | 
 |     const QuicSocketAddress& /*self_address*/, | 
 |     const QuicSocketAddress& peer_address) { | 
 |   if (perspective() == Perspective::IS_SERVER) { | 
 |     // Server only sends back a connectivity probe after received a | 
 |     // connectivity probe from a new peer address. | 
 |     connection_->SendConnectivityProbingResponsePacket(peer_address); | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::OnPathDegrading() {} | 
 |  | 
 | bool QuicSession::AllowSelfAddressChange() const { | 
 |   return false; | 
 | } | 
 |  | 
 | void QuicSession::OnForwardProgressConfirmed() {} | 
 |  | 
 | void QuicSession::OnWindowUpdateFrame(const QuicWindowUpdateFrame& frame) { | 
 |   // Stream may be closed by the time we receive a WINDOW_UPDATE, so we can't | 
 |   // assume that it still exists. | 
 |   QuicStreamId stream_id = frame.stream_id; | 
 |   if (stream_id == | 
 |       QuicUtils::GetInvalidStreamId(connection_->transport_version())) { | 
 |     // This is a window update that applies to the connection, rather than an | 
 |     // individual stream. | 
 |     QUIC_DLOG(INFO) << ENDPOINT | 
 |                     << "Received connection level flow control window " | 
 |                        "update with byte offset: " | 
 |                     << frame.byte_offset; | 
 |     flow_controller_.UpdateSendWindowOffset(frame.byte_offset); | 
 |     return; | 
 |   } | 
 |  | 
 |   if (VersionHasIetfQuicFrames(connection_->transport_version()) && | 
 |       QuicUtils::GetStreamType(stream_id, perspective(), | 
 |                                IsIncomingStream(stream_id)) == | 
 |           READ_UNIDIRECTIONAL) { | 
 |     connection()->CloseConnection( | 
 |         QUIC_WINDOW_UPDATE_RECEIVED_ON_READ_UNIDIRECTIONAL_STREAM, | 
 |         "WindowUpdateFrame received on READ_UNIDIRECTIONAL stream.", | 
 |         ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     return; | 
 |   } | 
 |  | 
 |   QuicStream* stream = GetOrCreateStream(stream_id); | 
 |   if (stream != nullptr) { | 
 |     stream->OnWindowUpdateFrame(frame); | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::OnBlockedFrame(const QuicBlockedFrame& frame) { | 
 |   // TODO(rjshade): Compare our flow control receive windows for specified | 
 |   //                streams: if we have a large window then maybe something | 
 |   //                had gone wrong with the flow control accounting. | 
 |   QUIC_DLOG(INFO) << ENDPOINT << "Received BLOCKED frame with stream id: " | 
 |                   << frame.stream_id; | 
 | } | 
 |  | 
 | bool QuicSession::CheckStreamNotBusyLooping(QuicStream* stream, | 
 |                                             uint64_t previous_bytes_written, | 
 |                                             bool previous_fin_sent) { | 
 |   if (  // Stream should not be closed. | 
 |       !stream->write_side_closed() && | 
 |       // Not connection flow control blocked. | 
 |       !flow_controller_.IsBlocked() && | 
 |       // Detect lack of forward progress. | 
 |       previous_bytes_written == stream->stream_bytes_written() && | 
 |       previous_fin_sent == stream->fin_sent()) { | 
 |     stream->set_busy_counter(stream->busy_counter() + 1); | 
 |     QUIC_DVLOG(1) << "Suspected busy loop on stream id " << stream->id() | 
 |                   << " stream_bytes_written " << stream->stream_bytes_written() | 
 |                   << " fin " << stream->fin_sent() << " count " | 
 |                   << stream->busy_counter(); | 
 |     // Wait a few iterations before firing, the exact count is | 
 |     // arbitrary, more than a few to cover a few test-only false | 
 |     // positives. | 
 |     if (stream->busy_counter() > 20) { | 
 |       QUIC_LOG(ERROR) << "Detected busy loop on stream id " << stream->id() | 
 |                       << " stream_bytes_written " | 
 |                       << stream->stream_bytes_written() << " fin " | 
 |                       << stream->fin_sent(); | 
 |       return false; | 
 |     } | 
 |   } else { | 
 |     stream->set_busy_counter(0); | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicSession::CheckStreamWriteBlocked(QuicStream* stream) const { | 
 |   if (!stream->write_side_closed() && stream->HasBufferedData() && | 
 |       !stream->flow_controller()->IsBlocked() && | 
 |       !write_blocked_streams_.IsStreamBlocked(stream->id())) { | 
 |     QUIC_DLOG(ERROR) << "stream " << stream->id() << " has buffered " | 
 |                      << stream->BufferedDataBytes() | 
 |                      << " bytes, and is not flow control blocked, " | 
 |                         "but it is not in the write block list."; | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | void QuicSession::OnCanWrite() { | 
 |   if (!RetransmitLostData()) { | 
 |     // Cannot finish retransmitting lost data, connection is write blocked. | 
 |     QUIC_DVLOG(1) << ENDPOINT | 
 |                   << "Cannot finish retransmitting lost data, connection is " | 
 |                      "write blocked."; | 
 |     return; | 
 |   } | 
 |   if (session_decides_what_to_write()) { | 
 |     SetTransmissionType(NOT_RETRANSMISSION); | 
 |   } | 
 |   // We limit the number of writes to the number of pending streams. If more | 
 |   // streams become pending, WillingAndAbleToWrite will be true, which will | 
 |   // cause the connection to request resumption before yielding to other | 
 |   // connections. | 
 |   // If we are connection level flow control blocked, then only allow the | 
 |   // crypto and headers streams to try writing as all other streams will be | 
 |   // blocked. | 
 |   size_t num_writes = flow_controller_.IsBlocked() | 
 |                           ? write_blocked_streams_.NumBlockedSpecialStreams() | 
 |                           : write_blocked_streams_.NumBlockedStreams(); | 
 |   if (num_writes == 0 && !control_frame_manager_.WillingToWrite()) { | 
 |     return; | 
 |   } | 
 |  | 
 |   QuicConnection::ScopedPacketFlusher flusher(connection_); | 
 |   if (control_frame_manager_.WillingToWrite()) { | 
 |     control_frame_manager_.OnCanWrite(); | 
 |   } | 
 |   for (size_t i = 0; i < num_writes; ++i) { | 
 |     if (!(write_blocked_streams_.HasWriteBlockedSpecialStream() || | 
 |           write_blocked_streams_.HasWriteBlockedDataStreams())) { | 
 |       // Writing one stream removed another!? Something's broken. | 
 |       QUIC_BUG << "WriteBlockedStream is missing"; | 
 |       connection_->CloseConnection(QUIC_INTERNAL_ERROR, | 
 |                                    "WriteBlockedStream is missing", | 
 |                                    ConnectionCloseBehavior::SILENT_CLOSE); | 
 |       return; | 
 |     } | 
 |     if (!connection_->CanWriteStreamData()) { | 
 |       return; | 
 |     } | 
 |     currently_writing_stream_id_ = write_blocked_streams_.PopFront(); | 
 |     QuicStream* stream = GetOrCreateStream(currently_writing_stream_id_); | 
 |     if (stream != nullptr && !stream->flow_controller()->IsBlocked()) { | 
 |       // If the stream can't write all bytes it'll re-add itself to the blocked | 
 |       // list. | 
 |       uint64_t previous_bytes_written = stream->stream_bytes_written(); | 
 |       bool previous_fin_sent = stream->fin_sent(); | 
 |       QUIC_DVLOG(1) << "stream " << stream->id() << " bytes_written " | 
 |                     << previous_bytes_written << " fin " << previous_fin_sent; | 
 |       stream->OnCanWrite(); | 
 |       DCHECK(CheckStreamWriteBlocked(stream)); | 
 |       DCHECK(CheckStreamNotBusyLooping(stream, previous_bytes_written, | 
 |                                        previous_fin_sent)); | 
 |     } | 
 |     currently_writing_stream_id_ = 0; | 
 |   } | 
 | } | 
 |  | 
 | bool QuicSession::SendProbingData() { | 
 |   if (connection()->sent_packet_manager().MaybeRetransmitOldestPacket( | 
 |           PROBING_RETRANSMISSION)) { | 
 |     return true; | 
 |   } | 
 |   return false; | 
 | } | 
 |  | 
 | bool QuicSession::WillingAndAbleToWrite() const { | 
 |   // Schedule a write when: | 
 |   // 1) control frame manager has pending or new control frames, or | 
 |   // 2) any stream has pending retransmissions, or | 
 |   // 3) If the crypto or headers streams are blocked, or | 
 |   // 4) connection is not flow control blocked and there are write blocked | 
 |   // streams. | 
 |   return control_frame_manager_.WillingToWrite() || | 
 |          !streams_with_pending_retransmission_.empty() || | 
 |          write_blocked_streams_.HasWriteBlockedSpecialStream() || | 
 |          (!flow_controller_.IsBlocked() && | 
 |           write_blocked_streams_.HasWriteBlockedDataStreams()); | 
 | } | 
 |  | 
 | bool QuicSession::HasPendingHandshake() const { | 
 |   if (QuicVersionUsesCryptoFrames(connection_->transport_version())) { | 
 |     // Writing CRYPTO frames is not subject to flow control, so there can't be | 
 |     // pending data to write, only pending retransmissions. | 
 |     return GetCryptoStream()->HasPendingCryptoRetransmission(); | 
 |   } | 
 |   return QuicContainsKey( | 
 |              streams_with_pending_retransmission_, | 
 |              QuicUtils::GetCryptoStreamId(connection_->transport_version())) || | 
 |          write_blocked_streams_.IsStreamBlocked( | 
 |              QuicUtils::GetCryptoStreamId(connection_->transport_version())); | 
 | } | 
 |  | 
 | uint64_t QuicSession::GetNumOpenDynamicStreams() const { | 
 |   return stream_map_.size() - draining_streams_.size() + | 
 |          locally_closed_streams_highest_offset_.size() - | 
 |          num_incoming_static_streams_ - num_outgoing_static_streams_; | 
 | } | 
 |  | 
 | void QuicSession::ProcessUdpPacket(const QuicSocketAddress& self_address, | 
 |                                    const QuicSocketAddress& peer_address, | 
 |                                    const QuicReceivedPacket& packet) { | 
 |   connection_->ProcessUdpPacket(self_address, peer_address, packet); | 
 | } | 
 |  | 
 | QuicConsumedData QuicSession::WritevData(QuicStream* stream, | 
 |                                          QuicStreamId id, | 
 |                                          size_t write_length, | 
 |                                          QuicStreamOffset offset, | 
 |                                          StreamSendingState state) { | 
 |   // This check is an attempt to deal with potential memory corruption | 
 |   // in which |id| ends up set to 1 (the crypto stream id). If this happen | 
 |   // it might end up resulting in unencrypted stream data being sent. | 
 |   // While this is impossible to avoid given sufficient corruption, this | 
 |   // seems like a reasonable mitigation. | 
 |   if (QuicUtils::IsCryptoStreamId(connection_->transport_version(), id) && | 
 |       stream != GetMutableCryptoStream()) { | 
 |     QUIC_BUG << "Stream id mismatch"; | 
 |     connection_->CloseConnection( | 
 |         QUIC_INTERNAL_ERROR, | 
 |         "Non-crypto stream attempted to write data as crypto stream.", | 
 |         ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     return QuicConsumedData(0, false); | 
 |   } | 
 |   if (!IsEncryptionEstablished() && | 
 |       !QuicUtils::IsCryptoStreamId(connection_->transport_version(), id)) { | 
 |     // Do not let streams write without encryption. The calling stream will end | 
 |     // up write blocked until OnCanWrite is next called. | 
 |     return QuicConsumedData(0, false); | 
 |   } | 
 |  | 
 |   QuicConsumedData data = | 
 |       connection_->SendStreamData(id, write_length, offset, state); | 
 |   if (offset >= stream->stream_bytes_written()) { | 
 |     // This is new stream data. | 
 |     write_blocked_streams_.UpdateBytesForStream(id, data.bytes_consumed); | 
 |   } | 
 |   return data; | 
 | } | 
 |  | 
 | bool QuicSession::WriteControlFrame(const QuicFrame& frame) { | 
 |   return connection_->SendControlFrame(frame); | 
 | } | 
 |  | 
 | void QuicSession::SendRstStream(QuicStreamId id, | 
 |                                 QuicRstStreamErrorCode error, | 
 |                                 QuicStreamOffset bytes_written) { | 
 |   SendRstStreamInner(id, error, bytes_written, /*close_write_side_only=*/false); | 
 | } | 
 |  | 
 | void QuicSession::SendRstStreamInner(QuicStreamId id, | 
 |                                      QuicRstStreamErrorCode error, | 
 |                                      QuicStreamOffset bytes_written, | 
 |                                      bool close_write_side_only) { | 
 |   if (connection()->connected()) { | 
 |     // Only send if still connected. | 
 |     if (close_write_side_only) { | 
 |       DCHECK(VersionHasIetfQuicFrames(connection_->transport_version())); | 
 |       // Send a RST_STREAM frame. | 
 |       control_frame_manager_.WriteOrBufferRstStream(id, error, bytes_written); | 
 |     } else { | 
 |       // Send a RST_STREAM frame plus, if version 99, an IETF | 
 |       // QUIC STOP_SENDING frame. Both sre sent to emulate | 
 |       // the two-way close that Google QUIC's RST_STREAM does. | 
 |       if (VersionHasIetfQuicFrames(connection_->transport_version())) { | 
 |         QuicConnection::ScopedPacketFlusher flusher(connection()); | 
 |         control_frame_manager_.WriteOrBufferRstStream(id, error, bytes_written); | 
 |         control_frame_manager_.WriteOrBufferStopSending(error, id); | 
 |       } else { | 
 |         control_frame_manager_.WriteOrBufferRstStream(id, error, bytes_written); | 
 |       } | 
 |     } | 
 |     connection_->OnStreamReset(id, error); | 
 |   } | 
 |   if (error != QUIC_STREAM_NO_ERROR && QuicContainsKey(zombie_streams_, id)) { | 
 |     OnStreamDoneWaitingForAcks(id); | 
 |     return; | 
 |   } | 
 |  | 
 |   if (!close_write_side_only) { | 
 |     CloseStreamInner(id, true); | 
 |     return; | 
 |   } | 
 |   DCHECK(VersionHasIetfQuicFrames(connection_->transport_version())); | 
 |  | 
 |   StreamMap::iterator it = stream_map_.find(id); | 
 |   if (it != stream_map_.end()) { | 
 |     if (it->second->is_static()) { | 
 |       QUIC_DVLOG(1) << ENDPOINT | 
 |                     << "Try to send rst for a static stream, id: " << id | 
 |                     << " Closing connection"; | 
 |       connection()->CloseConnection( | 
 |           QUIC_INVALID_STREAM_ID, "Sending rst for a static stream", | 
 |           ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |       return; | 
 |     } | 
 |     QuicStream* stream = it->second.get(); | 
 |     if (stream) { | 
 |       stream->set_rst_sent(true); | 
 |       stream->CloseWriteSide(); | 
 |     } | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::SendGoAway(QuicErrorCode error_code, | 
 |                              const std::string& reason) { | 
 |   // GOAWAY frame is not supported in v99. | 
 |   DCHECK(!VersionHasIetfQuicFrames(connection_->transport_version())); | 
 |   if (goaway_sent_) { | 
 |     return; | 
 |   } | 
 |   goaway_sent_ = true; | 
 |   control_frame_manager_.WriteOrBufferGoAway( | 
 |       error_code, stream_id_manager_.largest_peer_created_stream_id(), reason); | 
 | } | 
 |  | 
 | void QuicSession::SendBlocked(QuicStreamId id) { | 
 |   control_frame_manager_.WriteOrBufferBlocked(id); | 
 | } | 
 |  | 
 | void QuicSession::SendWindowUpdate(QuicStreamId id, | 
 |                                    QuicStreamOffset byte_offset) { | 
 |   control_frame_manager_.WriteOrBufferWindowUpdate(id, byte_offset); | 
 | } | 
 |  | 
 | void QuicSession::SendMaxStreams(QuicStreamCount stream_count, | 
 |                                  bool unidirectional) { | 
 |   control_frame_manager_.WriteOrBufferMaxStreams(stream_count, unidirectional); | 
 | } | 
 |  | 
 | void QuicSession::SendStreamsBlocked(QuicStreamCount stream_count, | 
 |                                      bool unidirectional) { | 
 |   control_frame_manager_.WriteOrBufferStreamsBlocked(stream_count, | 
 |                                                      unidirectional); | 
 | } | 
 |  | 
 | void QuicSession::CloseStream(QuicStreamId stream_id) { | 
 |   CloseStreamInner(stream_id, false); | 
 | } | 
 |  | 
 | void QuicSession::InsertLocallyClosedStreamsHighestOffset( | 
 |     const QuicStreamId id, | 
 |     QuicStreamOffset offset) { | 
 |   locally_closed_streams_highest_offset_[id] = offset; | 
 |   if (IsIncomingStream(id)) { | 
 |     ++num_locally_closed_incoming_streams_highest_offset_; | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::CloseStreamInner(QuicStreamId stream_id, bool locally_reset) { | 
 |   QUIC_DVLOG(1) << ENDPOINT << "Closing stream " << stream_id; | 
 |  | 
 |   StreamMap::iterator it = stream_map_.find(stream_id); | 
 |   if (it == stream_map_.end()) { | 
 |     // When CloseStreamInner has been called recursively (via | 
 |     // QuicStream::OnClose), the stream will already have been deleted | 
 |     // from stream_map_, so return immediately. | 
 |     QUIC_DVLOG(1) << ENDPOINT << "Stream is already closed: " << stream_id; | 
 |     return; | 
 |   } | 
 |   QuicStream* stream = it->second.get(); | 
 |   if (stream->is_static()) { | 
 |     QUIC_DVLOG(1) << ENDPOINT | 
 |                   << "Try to close a static stream, id: " << stream_id | 
 |                   << " Closing connection"; | 
 |     connection()->CloseConnection( | 
 |         QUIC_INVALID_STREAM_ID, "Try to close a static stream", | 
 |         ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     return; | 
 |   } | 
 |   StreamType type = stream->type(); | 
 |  | 
 |   // Tell the stream that a RST has been sent. | 
 |   if (locally_reset) { | 
 |     stream->set_rst_sent(true); | 
 |   } | 
 |  | 
 |   if (stream->IsWaitingForAcks()) { | 
 |     zombie_streams_[stream->id()] = std::move(it->second); | 
 |   } else { | 
 |     // Clean up the stream since it is no longer waiting for acks. | 
 |     if (ignore_tlpr_if_no_pending_stream_data() && | 
 |         session_decides_what_to_write()) { | 
 |       QUIC_RELOADABLE_FLAG_COUNT_N(quic_ignore_tlpr_if_no_pending_stream_data, | 
 |                                    2, 5); | 
 |       streams_waiting_for_acks_.erase(stream->id()); | 
 |     } | 
 |     closed_streams_.push_back(std::move(it->second)); | 
 |     // Do not retransmit data of a closed stream. | 
 |     streams_with_pending_retransmission_.erase(stream_id); | 
 |     if (!closed_streams_clean_up_alarm_->IsSet()) { | 
 |       closed_streams_clean_up_alarm_->Set( | 
 |           connection_->clock()->ApproximateNow()); | 
 |     } | 
 |   } | 
 |  | 
 |   // If we haven't received a FIN or RST for this stream, we need to keep track | 
 |   // of the how many bytes the stream's flow controller believes it has | 
 |   // received, for accurate connection level flow control accounting. | 
 |   const bool had_fin_or_rst = stream->HasFinalReceivedByteOffset(); | 
 |   if (!had_fin_or_rst) { | 
 |     InsertLocallyClosedStreamsHighestOffset( | 
 |         stream_id, stream->flow_controller()->highest_received_byte_offset()); | 
 |   } | 
 |   stream_map_.erase(it); | 
 |   if (IsIncomingStream(stream_id)) { | 
 |     --num_dynamic_incoming_streams_; | 
 |   } | 
 |  | 
 |   const bool stream_was_draining = | 
 |       draining_streams_.find(stream_id) != draining_streams_.end(); | 
 |   if (stream_was_draining) { | 
 |     if (IsIncomingStream(stream_id)) { | 
 |       --num_draining_incoming_streams_; | 
 |     } | 
 |     draining_streams_.erase(stream_id); | 
 |   } else if (VersionHasIetfQuicFrames(connection_->transport_version())) { | 
 |     // Stream was not draining, but we did have a fin or rst, so we can now | 
 |     // free the stream ID if version 99. | 
 |     if (had_fin_or_rst) { | 
 |       v99_streamid_manager_.OnStreamClosed(stream_id); | 
 |     } | 
 |   } | 
 |  | 
 |   stream->OnClose(); | 
 |  | 
 |   if (!stream_was_draining && !IsIncomingStream(stream_id) && had_fin_or_rst && | 
 |       !VersionHasIetfQuicFrames(connection_->transport_version())) { | 
 |     // Streams that first became draining already called OnCanCreate... | 
 |     // This covers the case where the stream went directly to being closed. | 
 |     OnCanCreateNewOutgoingStream(type != BIDIRECTIONAL); | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::ClosePendingStream(QuicStreamId stream_id) { | 
 |   QUIC_DVLOG(1) << ENDPOINT << "Closing stream " << stream_id; | 
 |  | 
 |   if (pending_stream_map_.find(stream_id) == pending_stream_map_.end()) { | 
 |     QUIC_BUG << ENDPOINT << "Stream is already closed: " << stream_id; | 
 |     return; | 
 |   } | 
 |  | 
 |   SendRstStream(stream_id, QUIC_RST_ACKNOWLEDGEMENT, 0); | 
 |  | 
 |   // The pending stream may have been deleted and removed during SendRstStream. | 
 |   // Remove the stream from pending stream map iff it is still in the map. | 
 |   if (pending_stream_map_.find(stream_id) != pending_stream_map_.end()) { | 
 |     pending_stream_map_.erase(stream_id); | 
 |   } | 
 |  | 
 |   if (VersionHasIetfQuicFrames(connection_->transport_version())) { | 
 |     v99_streamid_manager_.OnStreamClosed(stream_id); | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::OnFinalByteOffsetReceived( | 
 |     QuicStreamId stream_id, | 
 |     QuicStreamOffset final_byte_offset) { | 
 |   auto it = locally_closed_streams_highest_offset_.find(stream_id); | 
 |   if (it == locally_closed_streams_highest_offset_.end()) { | 
 |     return; | 
 |   } | 
 |  | 
 |   QUIC_DVLOG(1) << ENDPOINT << "Received final byte offset " | 
 |                 << final_byte_offset << " for stream " << stream_id; | 
 |   QuicByteCount offset_diff = final_byte_offset - it->second; | 
 |   if (flow_controller_.UpdateHighestReceivedOffset( | 
 |           flow_controller_.highest_received_byte_offset() + offset_diff)) { | 
 |     // If the final offset violates flow control, close the connection now. | 
 |     if (flow_controller_.FlowControlViolation()) { | 
 |       connection_->CloseConnection( | 
 |           QUIC_FLOW_CONTROL_RECEIVED_TOO_MUCH_DATA, | 
 |           "Connection level flow control violation", | 
 |           ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |       return; | 
 |     } | 
 |   } | 
 |  | 
 |   flow_controller_.AddBytesConsumed(offset_diff); | 
 |   locally_closed_streams_highest_offset_.erase(it); | 
 |   if (IsIncomingStream(stream_id)) { | 
 |     --num_locally_closed_incoming_streams_highest_offset_; | 
 |     if (VersionHasIetfQuicFrames(connection_->transport_version())) { | 
 |       v99_streamid_manager_.OnStreamClosed(stream_id); | 
 |     } | 
 |   } else if (!VersionHasIetfQuicFrames(connection_->transport_version())) { | 
 |     OnCanCreateNewOutgoingStream(false); | 
 |   } | 
 | } | 
 |  | 
 | bool QuicSession::IsEncryptionEstablished() const { | 
 |   // Once the handshake is confirmed, it never becomes un-confirmed. | 
 |   if (is_handshake_confirmed_) { | 
 |     return true; | 
 |   } | 
 |   return GetCryptoStream()->encryption_established(); | 
 | } | 
 |  | 
 | bool QuicSession::IsCryptoHandshakeConfirmed() const { | 
 |   return GetCryptoStream()->handshake_confirmed(); | 
 | } | 
 |  | 
 | void QuicSession::OnConfigNegotiated() { | 
 |   connection_->SetFromConfig(config_); | 
 |  | 
 |   if (VersionHasIetfQuicFrames(connection_->transport_version())) { | 
 |     uint32_t max_streams = 0; | 
 |     if (config_.HasReceivedMaxIncomingBidirectionalStreams()) { | 
 |       max_streams = config_.ReceivedMaxIncomingBidirectionalStreams(); | 
 |     } | 
 |     QUIC_DVLOG(1) << "Setting Bidirectional outgoing_max_streams_ to " | 
 |                   << max_streams; | 
 |     v99_streamid_manager_.AdjustMaxOpenOutgoingBidirectionalStreams( | 
 |         max_streams); | 
 |  | 
 |     max_streams = 0; | 
 |     if (config_.HasReceivedMaxIncomingUnidirectionalStreams()) { | 
 |       max_streams = config_.ReceivedMaxIncomingUnidirectionalStreams(); | 
 |     } | 
 |     QUIC_DVLOG(1) << "Setting Unidirectional outgoing_max_streams_ to " | 
 |                   << max_streams; | 
 |     v99_streamid_manager_.AdjustMaxOpenOutgoingUnidirectionalStreams( | 
 |         max_streams); | 
 |   } else { | 
 |     uint32_t max_streams = 0; | 
 |     if (config_.HasReceivedMaxIncomingBidirectionalStreams()) { | 
 |       max_streams = config_.ReceivedMaxIncomingBidirectionalStreams(); | 
 |     } | 
 |     QUIC_DVLOG(1) << "Setting max_open_outgoing_streams_ to " << max_streams; | 
 |     stream_id_manager_.set_max_open_outgoing_streams(max_streams); | 
 |   } | 
 |  | 
 |   if (perspective() == Perspective::IS_SERVER) { | 
 |     if (config_.HasReceivedConnectionOptions()) { | 
 |       // The following variations change the initial receive flow control | 
 |       // window sizes. | 
 |       if (ContainsQuicTag(config_.ReceivedConnectionOptions(), kIFW6)) { | 
 |         AdjustInitialFlowControlWindows(64 * 1024); | 
 |       } | 
 |       if (ContainsQuicTag(config_.ReceivedConnectionOptions(), kIFW7)) { | 
 |         AdjustInitialFlowControlWindows(128 * 1024); | 
 |       } | 
 |       if (ContainsQuicTag(config_.ReceivedConnectionOptions(), kIFW8)) { | 
 |         AdjustInitialFlowControlWindows(256 * 1024); | 
 |       } | 
 |       if (ContainsQuicTag(config_.ReceivedConnectionOptions(), kIFW9)) { | 
 |         AdjustInitialFlowControlWindows(512 * 1024); | 
 |       } | 
 |       if (ContainsQuicTag(config_.ReceivedConnectionOptions(), kIFWA)) { | 
 |         AdjustInitialFlowControlWindows(1024 * 1024); | 
 |       } | 
 |     } | 
 |  | 
 |     config_.SetStatelessResetTokenToSend(GetStatelessResetToken()); | 
 |   } | 
 |  | 
 |   if (VersionHasIetfQuicFrames(connection_->transport_version())) { | 
 |     v99_streamid_manager_.SetMaxOpenIncomingBidirectionalStreams( | 
 |         config_.GetMaxIncomingBidirectionalStreamsToSend()); | 
 |     v99_streamid_manager_.SetMaxOpenIncomingUnidirectionalStreams( | 
 |         config_.GetMaxIncomingUnidirectionalStreamsToSend()); | 
 |   } else { | 
 |     // A small number of additional incoming streams beyond the limit should be | 
 |     // allowed. This helps avoid early connection termination when FIN/RSTs for | 
 |     // old streams are lost or arrive out of order. | 
 |     // Use a minimum number of additional streams, or a percentage increase, | 
 |     // whichever is larger. | 
 |     uint32_t max_incoming_streams_to_send = | 
 |         config_.GetMaxIncomingBidirectionalStreamsToSend(); | 
 |     uint32_t max_incoming_streams = | 
 |         std::max(max_incoming_streams_to_send + kMaxStreamsMinimumIncrement, | 
 |                  static_cast<uint32_t>(max_incoming_streams_to_send * | 
 |                                        kMaxStreamsMultiplier)); | 
 |     stream_id_manager_.set_max_open_incoming_streams(max_incoming_streams); | 
 |   } | 
 |  | 
 |   if (config_.HasReceivedInitialStreamFlowControlWindowBytes()) { | 
 |     // Streams which were created before the SHLO was received (0-RTT | 
 |     // requests) are now informed of the peer's initial flow control window. | 
 |     OnNewStreamFlowControlWindow( | 
 |         config_.ReceivedInitialStreamFlowControlWindowBytes()); | 
 |   } | 
 |   if (config_.HasReceivedInitialSessionFlowControlWindowBytes()) { | 
 |     OnNewSessionFlowControlWindow( | 
 |         config_.ReceivedInitialSessionFlowControlWindowBytes()); | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::AdjustInitialFlowControlWindows(size_t stream_window) { | 
 |   const float session_window_multiplier = | 
 |       config_.GetInitialStreamFlowControlWindowToSend() | 
 |           ? static_cast<float>( | 
 |                 config_.GetInitialSessionFlowControlWindowToSend()) / | 
 |                 config_.GetInitialStreamFlowControlWindowToSend() | 
 |           : 1.5; | 
 |  | 
 |   QUIC_DVLOG(1) << ENDPOINT << "Set stream receive window to " << stream_window; | 
 |   config_.SetInitialStreamFlowControlWindowToSend(stream_window); | 
 |  | 
 |   size_t session_window = session_window_multiplier * stream_window; | 
 |   QUIC_DVLOG(1) << ENDPOINT << "Set session receive window to " | 
 |                 << session_window; | 
 |   config_.SetInitialSessionFlowControlWindowToSend(session_window); | 
 |   flow_controller_.UpdateReceiveWindowSize(session_window); | 
 |   // Inform all existing streams about the new window. | 
 |   for (auto const& kv : stream_map_) { | 
 |     kv.second->flow_controller()->UpdateReceiveWindowSize(stream_window); | 
 |   } | 
 |   if (!QuicVersionUsesCryptoFrames(connection_->transport_version())) { | 
 |     GetMutableCryptoStream()->flow_controller()->UpdateReceiveWindowSize( | 
 |         stream_window); | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::HandleFrameOnNonexistentOutgoingStream( | 
 |     QuicStreamId stream_id) { | 
 |   DCHECK(!IsClosedStream(stream_id)); | 
 |   // Received a frame for a locally-created stream that is not currently | 
 |   // active. This is an error. | 
 |   connection()->CloseConnection( | 
 |       QUIC_INVALID_STREAM_ID, "Data for nonexistent stream", | 
 |       ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 | } | 
 |  | 
 | void QuicSession::HandleRstOnValidNonexistentStream( | 
 |     const QuicRstStreamFrame& frame) { | 
 |   // If the stream is neither originally in active streams nor created in | 
 |   // GetOrCreateStream(), it could be a closed stream in which case its | 
 |   // final received byte offset need to be updated. | 
 |   if (IsClosedStream(frame.stream_id)) { | 
 |     // The RST frame contains the final byte offset for the stream: we can now | 
 |     // update the connection level flow controller if needed. | 
 |     OnFinalByteOffsetReceived(frame.stream_id, frame.byte_offset); | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::OnNewStreamFlowControlWindow(QuicStreamOffset new_window) { | 
 |   if (new_window < kMinimumFlowControlSendWindow && | 
 |       !connection_->version().AllowsLowFlowControlLimits()) { | 
 |     QUIC_LOG_FIRST_N(ERROR, 1) | 
 |         << "Peer sent us an invalid stream flow control send window: " | 
 |         << new_window << ", below minimum: " << kMinimumFlowControlSendWindow; | 
 |     if (connection_->connected()) { | 
 |       connection_->CloseConnection( | 
 |           QUIC_FLOW_CONTROL_INVALID_WINDOW, "New stream window too low", | 
 |           ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     } | 
 |     return; | 
 |   } | 
 |  | 
 |   // Inform all existing streams about the new window. | 
 |   for (auto const& kv : stream_map_) { | 
 |     kv.second->UpdateSendWindowOffset(new_window); | 
 |   } | 
 |   if (!QuicVersionUsesCryptoFrames(connection_->transport_version())) { | 
 |     GetMutableCryptoStream()->UpdateSendWindowOffset(new_window); | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::OnNewSessionFlowControlWindow(QuicStreamOffset new_window) { | 
 |   if (new_window < kMinimumFlowControlSendWindow && | 
 |       !connection_->version().AllowsLowFlowControlLimits()) { | 
 |     QUIC_LOG_FIRST_N(ERROR, 1) | 
 |         << "Peer sent us an invalid session flow control send window: " | 
 |         << new_window << ", below default: " << kMinimumFlowControlSendWindow; | 
 |     if (connection_->connected()) { | 
 |       connection_->CloseConnection( | 
 |           QUIC_FLOW_CONTROL_INVALID_WINDOW, "New connection window too low", | 
 |           ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     } | 
 |     return; | 
 |   } | 
 |  | 
 |   flow_controller_.UpdateSendWindowOffset(new_window); | 
 | } | 
 |  | 
 | void QuicSession::OnCryptoHandshakeEvent(CryptoHandshakeEvent event) { | 
 |   switch (event) { | 
 |     // TODO(satyamshekhar): Move the logic of setting the encrypter/decrypter | 
 |     // to QuicSession since it is the glue. | 
 |     case ENCRYPTION_FIRST_ESTABLISHED: | 
 |       // Given any streams blocked by encryption a chance to write. | 
 |       OnCanWrite(); | 
 |       break; | 
 |  | 
 |     case ENCRYPTION_REESTABLISHED: | 
 |       // Retransmit originally packets that were sent, since they can't be | 
 |       // decrypted by the peer. | 
 |       connection_->RetransmitUnackedPackets(ALL_INITIAL_RETRANSMISSION); | 
 |       // Given any streams blocked by encryption a chance to write. | 
 |       OnCanWrite(); | 
 |       break; | 
 |  | 
 |     case HANDSHAKE_CONFIRMED: | 
 |       QUIC_BUG_IF(!config_.negotiated()) | 
 |           << ENDPOINT << "Handshake confirmed without parameter negotiation."; | 
 |       // Discard originally encrypted packets, since they can't be decrypted by | 
 |       // the peer. | 
 |       NeuterUnencryptedData(); | 
 |       is_handshake_confirmed_ = true; | 
 |       break; | 
 |  | 
 |     default: | 
 |       QUIC_LOG(ERROR) << ENDPOINT << "Got unknown handshake event: " << event; | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::OnCryptoHandshakeMessageSent( | 
 |     const CryptoHandshakeMessage& /*message*/) {} | 
 |  | 
 | void QuicSession::OnCryptoHandshakeMessageReceived( | 
 |     const CryptoHandshakeMessage& /*message*/) {} | 
 |  | 
 | void QuicSession::RegisterStreamPriority(QuicStreamId id, | 
 |                                          bool is_static, | 
 |                                          SpdyPriority priority) { | 
 |   write_blocked_streams()->RegisterStream(id, is_static, priority); | 
 | } | 
 |  | 
 | void QuicSession::UnregisterStreamPriority(QuicStreamId id, bool is_static) { | 
 |   write_blocked_streams()->UnregisterStream(id, is_static); | 
 | } | 
 |  | 
 | void QuicSession::UpdateStreamPriority(QuicStreamId id, | 
 |                                        SpdyPriority new_priority) { | 
 |   write_blocked_streams()->UpdateStreamPriority(id, new_priority); | 
 | } | 
 |  | 
 | QuicConfig* QuicSession::config() { | 
 |   return &config_; | 
 | } | 
 |  | 
 | void QuicSession::ActivateStream(std::unique_ptr<QuicStream> stream) { | 
 |   DCHECK(!stream->is_static()); | 
 |   QuicStreamId stream_id = stream->id(); | 
 |   QUIC_DVLOG(1) << ENDPOINT << "num_streams: " << stream_map_.size() | 
 |                 << ". activating " << stream_id; | 
 |   DCHECK(!QuicContainsKey(stream_map_, stream_id)); | 
 |   stream_map_[stream_id] = std::move(stream); | 
 |   if (IsIncomingStream(stream_id)) { | 
 |     ++num_dynamic_incoming_streams_; | 
 |   } | 
 | } | 
 |  | 
 | QuicStreamId QuicSession::GetNextOutgoingBidirectionalStreamId() { | 
 |   if (VersionHasIetfQuicFrames(connection_->transport_version())) { | 
 |     return v99_streamid_manager_.GetNextOutgoingBidirectionalStreamId(); | 
 |   } | 
 |   return stream_id_manager_.GetNextOutgoingStreamId(); | 
 | } | 
 |  | 
 | QuicStreamId QuicSession::GetNextOutgoingUnidirectionalStreamId() { | 
 |   if (VersionHasIetfQuicFrames(connection_->transport_version())) { | 
 |     return v99_streamid_manager_.GetNextOutgoingUnidirectionalStreamId(); | 
 |   } | 
 |   return stream_id_manager_.GetNextOutgoingStreamId(); | 
 | } | 
 |  | 
 | bool QuicSession::CanOpenNextOutgoingBidirectionalStream() { | 
 |   if (VersionHasIetfQuicFrames(connection_->transport_version())) { | 
 |     return v99_streamid_manager_.CanOpenNextOutgoingBidirectionalStream(); | 
 |   } | 
 |   return stream_id_manager_.CanOpenNextOutgoingStream( | 
 |       GetNumOpenOutgoingStreams()); | 
 | } | 
 |  | 
 | bool QuicSession::CanOpenNextOutgoingUnidirectionalStream() { | 
 |   if (VersionHasIetfQuicFrames(connection_->transport_version())) { | 
 |     return v99_streamid_manager_.CanOpenNextOutgoingUnidirectionalStream(); | 
 |   } | 
 |   return stream_id_manager_.CanOpenNextOutgoingStream( | 
 |       GetNumOpenOutgoingStreams()); | 
 | } | 
 |  | 
 | QuicStream* QuicSession::GetOrCreateStream(const QuicStreamId stream_id) { | 
 |   DCHECK(!QuicContainsKey(pending_stream_map_, stream_id)); | 
 |   if (QuicUtils::IsCryptoStreamId(connection_->transport_version(), | 
 |                                   stream_id)) { | 
 |     return GetMutableCryptoStream(); | 
 |   } | 
 |  | 
 |   StreamMap::iterator it = stream_map_.find(stream_id); | 
 |   if (it != stream_map_.end()) { | 
 |     return it->second.get(); | 
 |   } | 
 |  | 
 |   if (IsClosedStream(stream_id)) { | 
 |     return nullptr; | 
 |   } | 
 |  | 
 |   if (!IsIncomingStream(stream_id)) { | 
 |     HandleFrameOnNonexistentOutgoingStream(stream_id); | 
 |     return nullptr; | 
 |   } | 
 |  | 
 |   // TODO(fkastenholz): If we are creating a new stream and we have | 
 |   // sent a goaway, we should ignore the stream creation. Need to | 
 |   // add code to A) test if goaway was sent ("if (goaway_sent_)") and | 
 |   // B) reject stream creation ("return nullptr") | 
 |  | 
 |   if (!MaybeIncreaseLargestPeerStreamId(stream_id)) { | 
 |     return nullptr; | 
 |   } | 
 |  | 
 |   if (!VersionHasIetfQuicFrames(connection_->transport_version())) { | 
 |     // TODO(fayang): Let LegacyQuicStreamIdManager count open streams and make | 
 |     // CanOpenIncomingStream interface consistent with that of v99. | 
 |     if (!stream_id_manager_.CanOpenIncomingStream( | 
 |             GetNumOpenIncomingStreams())) { | 
 |       // Refuse to open the stream. | 
 |       SendRstStream(stream_id, QUIC_REFUSED_STREAM, 0); | 
 |       return nullptr; | 
 |     } | 
 |   } | 
 |  | 
 |   return CreateIncomingStream(stream_id); | 
 | } | 
 |  | 
 | void QuicSession::StreamDraining(QuicStreamId stream_id) { | 
 |   DCHECK(QuicContainsKey(stream_map_, stream_id)); | 
 |   if (!QuicContainsKey(draining_streams_, stream_id)) { | 
 |     draining_streams_.insert(stream_id); | 
 |     if (IsIncomingStream(stream_id)) { | 
 |       ++num_draining_incoming_streams_; | 
 |     } | 
 |     if (VersionHasIetfQuicFrames(connection_->transport_version())) { | 
 |       v99_streamid_manager_.OnStreamClosed(stream_id); | 
 |     } | 
 |   } | 
 |   if (!IsIncomingStream(stream_id)) { | 
 |     // Inform application that a stream is available. | 
 |     if (VersionHasIetfQuicFrames(connection_->transport_version())) { | 
 |       OnCanCreateNewOutgoingStream( | 
 |           !QuicUtils::IsBidirectionalStreamId(stream_id)); | 
 |     } else { | 
 |       QuicStream* stream = GetStream(stream_id); | 
 |       if (!stream) { | 
 |         QUIC_BUG << "Stream doesn't exist when draining."; | 
 |         return; | 
 |       } | 
 |       OnCanCreateNewOutgoingStream(stream->type() != BIDIRECTIONAL); | 
 |     } | 
 |   } | 
 | } | 
 |  | 
 | bool QuicSession::MaybeIncreaseLargestPeerStreamId( | 
 |     const QuicStreamId stream_id) { | 
 |   if (VersionHasIetfQuicFrames(connection_->transport_version())) { | 
 |     return v99_streamid_manager_.MaybeIncreaseLargestPeerStreamId(stream_id); | 
 |   } | 
 |   return stream_id_manager_.MaybeIncreaseLargestPeerStreamId(stream_id); | 
 | } | 
 |  | 
 | bool QuicSession::ShouldYield(QuicStreamId stream_id) { | 
 |   if (stream_id == currently_writing_stream_id_) { | 
 |     return false; | 
 |   } | 
 |   return write_blocked_streams()->ShouldYield(stream_id); | 
 | } | 
 |  | 
 | PendingStream* QuicSession::GetOrCreatePendingStream(QuicStreamId stream_id) { | 
 |   auto it = pending_stream_map_.find(stream_id); | 
 |   if (it != pending_stream_map_.end()) { | 
 |     return it->second.get(); | 
 |   } | 
 |  | 
 |   if (IsClosedStream(stream_id) || | 
 |       !MaybeIncreaseLargestPeerStreamId(stream_id)) { | 
 |     return nullptr; | 
 |   } | 
 |  | 
 |   auto pending = QuicMakeUnique<PendingStream>(stream_id, this); | 
 |   PendingStream* unowned_pending = pending.get(); | 
 |   pending_stream_map_[stream_id] = std::move(pending); | 
 |   return unowned_pending; | 
 | } | 
 |  | 
 | QuicStream* QuicSession::GetOrCreateDynamicStream( | 
 |     const QuicStreamId stream_id) { | 
 |   DCHECK(!GetQuicReloadableFlag(quic_inline_getorcreatedynamicstream)); | 
 |   StreamMap::iterator it = stream_map_.find(stream_id); | 
 |   if (it != stream_map_.end()) { | 
 |     return it->second.get(); | 
 |   } | 
 |  | 
 |   if (IsClosedStream(stream_id)) { | 
 |     return nullptr; | 
 |   } | 
 |  | 
 |   if (!IsIncomingStream(stream_id)) { | 
 |     HandleFrameOnNonexistentOutgoingStream(stream_id); | 
 |     return nullptr; | 
 |   } | 
 |  | 
 |   // TODO(fkastenholz): If we are creating a new stream and we have | 
 |   // sent a goaway, we should ignore the stream creation. Need to | 
 |   // add code to A) test if goaway was sent ("if (goaway_sent_)") and | 
 |   // B) reject stream creation ("return nullptr") | 
 |  | 
 |   if (!MaybeIncreaseLargestPeerStreamId(stream_id)) { | 
 |     return nullptr; | 
 |   } | 
 |  | 
 |   if (!VersionHasIetfQuicFrames(connection_->transport_version())) { | 
 |     // TODO(fayang): Let LegacyQuicStreamIdManager count open streams and make | 
 |     // CanOpenIncomingStream interface cosistent with that of v99. | 
 |     if (!stream_id_manager_.CanOpenIncomingStream( | 
 |             GetNumOpenIncomingStreams())) { | 
 |       // Refuse to open the stream. | 
 |       SendRstStream(stream_id, QUIC_REFUSED_STREAM, 0); | 
 |       return nullptr; | 
 |     } | 
 |   } | 
 |  | 
 |   return CreateIncomingStream(stream_id); | 
 | } | 
 |  | 
 | void QuicSession::set_largest_peer_created_stream_id( | 
 |     QuicStreamId largest_peer_created_stream_id) { | 
 |   if (VersionHasIetfQuicFrames(connection_->transport_version())) { | 
 |     v99_streamid_manager_.SetLargestPeerCreatedStreamId( | 
 |         largest_peer_created_stream_id); | 
 |     return; | 
 |   } | 
 |   stream_id_manager_.set_largest_peer_created_stream_id( | 
 |       largest_peer_created_stream_id); | 
 | } | 
 |  | 
 | bool QuicSession::IsClosedStream(QuicStreamId id) { | 
 |   DCHECK_NE(QuicUtils::GetInvalidStreamId(connection_->transport_version()), | 
 |             id); | 
 |   if (IsOpenStream(id)) { | 
 |     // Stream is active | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (VersionHasIetfQuicFrames(connection_->transport_version())) { | 
 |     return !v99_streamid_manager_.IsAvailableStream(id); | 
 |   } | 
 |  | 
 |   return !stream_id_manager_.IsAvailableStream(id); | 
 | } | 
 |  | 
 | bool QuicSession::IsOpenStream(QuicStreamId id) { | 
 |   DCHECK_NE(QuicUtils::GetInvalidStreamId(connection_->transport_version()), | 
 |             id); | 
 |   if (QuicContainsKey(stream_map_, id) || | 
 |       QuicContainsKey(pending_stream_map_, id) || | 
 |       QuicUtils::IsCryptoStreamId(connection_->transport_version(), id)) { | 
 |     // Stream is active | 
 |     return true; | 
 |   } | 
 |   return false; | 
 | } | 
 |  | 
 | bool QuicSession::IsStaticStream(QuicStreamId id) const { | 
 |   auto it = stream_map_.find(id); | 
 |   if (it == stream_map_.end()) { | 
 |     return false; | 
 |   } | 
 |   return it->second->is_static(); | 
 | } | 
 |  | 
 | size_t QuicSession::GetNumOpenIncomingStreams() const { | 
 |   return num_dynamic_incoming_streams_ - num_draining_incoming_streams_ + | 
 |          num_locally_closed_incoming_streams_highest_offset_; | 
 | } | 
 |  | 
 | size_t QuicSession::GetNumOpenOutgoingStreams() const { | 
 |   DCHECK_GE(GetNumDynamicOutgoingStreams() + | 
 |                 GetNumLocallyClosedOutgoingStreamsHighestOffset(), | 
 |             GetNumDrainingOutgoingStreams()); | 
 |   return GetNumDynamicOutgoingStreams() + | 
 |          GetNumLocallyClosedOutgoingStreamsHighestOffset() - | 
 |          GetNumDrainingOutgoingStreams(); | 
 | } | 
 |  | 
 | size_t QuicSession::GetNumActiveStreams() const { | 
 |   return stream_map_.size() - draining_streams_.size() - | 
 |          num_incoming_static_streams_ - num_outgoing_static_streams_; | 
 | } | 
 |  | 
 | size_t QuicSession::GetNumDrainingStreams() const { | 
 |   return draining_streams_.size(); | 
 | } | 
 |  | 
 | void QuicSession::MarkConnectionLevelWriteBlocked(QuicStreamId id) { | 
 |   if (GetOrCreateStream(id) == nullptr) { | 
 |     QUIC_BUG << "Marking unknown stream " << id << " blocked."; | 
 |     QUIC_LOG_FIRST_N(ERROR, 2) << QuicStackTrace(); | 
 |   } | 
 |  | 
 |   write_blocked_streams_.AddStream(id); | 
 | } | 
 |  | 
 | bool QuicSession::HasDataToWrite() const { | 
 |   return write_blocked_streams_.HasWriteBlockedSpecialStream() || | 
 |          write_blocked_streams_.HasWriteBlockedDataStreams() || | 
 |          connection_->HasQueuedData() || | 
 |          !streams_with_pending_retransmission_.empty() || | 
 |          control_frame_manager_.WillingToWrite(); | 
 | } | 
 |  | 
 | void QuicSession::OnAckNeedsRetransmittableFrame() { | 
 |   flow_controller_.SendWindowUpdate(); | 
 | } | 
 |  | 
 | void QuicSession::SendPing() { | 
 |   control_frame_manager_.WritePing(); | 
 | } | 
 |  | 
 | size_t QuicSession::GetNumDynamicOutgoingStreams() const { | 
 |   DCHECK_GE( | 
 |       static_cast<size_t>(stream_map_.size() + pending_stream_map_.size()), | 
 |       num_dynamic_incoming_streams_ + num_outgoing_static_streams_ + | 
 |           num_incoming_static_streams_); | 
 |   return stream_map_.size() + pending_stream_map_.size() - | 
 |          num_dynamic_incoming_streams_ - num_outgoing_static_streams_ - | 
 |          num_incoming_static_streams_; | 
 | } | 
 |  | 
 | size_t QuicSession::GetNumDrainingOutgoingStreams() const { | 
 |   DCHECK_GE(draining_streams_.size(), num_draining_incoming_streams_); | 
 |   return draining_streams_.size() - num_draining_incoming_streams_; | 
 | } | 
 |  | 
 | size_t QuicSession::GetNumLocallyClosedOutgoingStreamsHighestOffset() const { | 
 |   DCHECK_GE(locally_closed_streams_highest_offset_.size(), | 
 |             num_locally_closed_incoming_streams_highest_offset_); | 
 |   return locally_closed_streams_highest_offset_.size() - | 
 |          num_locally_closed_incoming_streams_highest_offset_; | 
 | } | 
 |  | 
 | bool QuicSession::IsConnectionFlowControlBlocked() const { | 
 |   return flow_controller_.IsBlocked(); | 
 | } | 
 |  | 
 | bool QuicSession::IsStreamFlowControlBlocked() { | 
 |   for (auto const& kv : stream_map_) { | 
 |     if (kv.second->flow_controller()->IsBlocked()) { | 
 |       return true; | 
 |     } | 
 |   } | 
 |   if (!QuicVersionUsesCryptoFrames(connection_->transport_version()) && | 
 |       GetMutableCryptoStream()->flow_controller()->IsBlocked()) { | 
 |     return true; | 
 |   } | 
 |   return false; | 
 | } | 
 |  | 
 | size_t QuicSession::MaxAvailableBidirectionalStreams() const { | 
 |   if (VersionHasIetfQuicFrames(connection()->transport_version())) { | 
 |     return v99_streamid_manager_.GetMaxAllowdIncomingBidirectionalStreams(); | 
 |   } | 
 |   return stream_id_manager_.MaxAvailableStreams(); | 
 | } | 
 |  | 
 | size_t QuicSession::MaxAvailableUnidirectionalStreams() const { | 
 |   if (VersionHasIetfQuicFrames(connection()->transport_version())) { | 
 |     return v99_streamid_manager_.GetMaxAllowdIncomingUnidirectionalStreams(); | 
 |   } | 
 |   return stream_id_manager_.MaxAvailableStreams(); | 
 | } | 
 |  | 
 | bool QuicSession::IsIncomingStream(QuicStreamId id) const { | 
 |   if (VersionHasIetfQuicFrames(connection()->transport_version())) { | 
 |     return v99_streamid_manager_.IsIncomingStream(id); | 
 |   } | 
 |   return stream_id_manager_.IsIncomingStream(id); | 
 | } | 
 |  | 
 | void QuicSession::OnStreamDoneWaitingForAcks(QuicStreamId id) { | 
 |   if (ignore_tlpr_if_no_pending_stream_data() && | 
 |       session_decides_what_to_write()) { | 
 |     QUIC_RELOADABLE_FLAG_COUNT_N(quic_ignore_tlpr_if_no_pending_stream_data, 3, | 
 |                                  5); | 
 |     streams_waiting_for_acks_.erase(id); | 
 |   } | 
 |  | 
 |   auto it = zombie_streams_.find(id); | 
 |   if (it == zombie_streams_.end()) { | 
 |     return; | 
 |   } | 
 |  | 
 |   closed_streams_.push_back(std::move(it->second)); | 
 |   if (!closed_streams_clean_up_alarm_->IsSet()) { | 
 |     closed_streams_clean_up_alarm_->Set(connection_->clock()->ApproximateNow()); | 
 |   } | 
 |   zombie_streams_.erase(it); | 
 |   // Do not retransmit data of a closed stream. | 
 |   streams_with_pending_retransmission_.erase(id); | 
 | } | 
 |  | 
 | void QuicSession::OnStreamWaitingForAcks(QuicStreamId id) { | 
 |   if (!ignore_tlpr_if_no_pending_stream_data() || | 
 |       !session_decides_what_to_write()) | 
 |     return; | 
 |  | 
 |   // Exclude crypto stream's status since it is counted in HasUnackedCryptoData. | 
 |   if (GetCryptoStream() != nullptr && id == GetCryptoStream()->id()) { | 
 |     return; | 
 |   } | 
 |  | 
 |   QUIC_RELOADABLE_FLAG_COUNT_N(quic_ignore_tlpr_if_no_pending_stream_data, 4, | 
 |                                5); | 
 |   streams_waiting_for_acks_.insert(id); | 
 |  | 
 |   // The number of the streams waiting for acks should not be larger than the | 
 |   // number of streams. | 
 |   if (static_cast<size_t>(stream_map_.size() + zombie_streams_.size()) < | 
 |       streams_waiting_for_acks_.size()) { | 
 |     QUIC_BUG << "More streams are waiting for acks than the number of streams. " | 
 |              << "Sizes: streams: " << stream_map_.size() | 
 |              << ", zombie streams: " << zombie_streams_.size() | 
 |              << ", vs streams waiting for acks: " | 
 |              << streams_waiting_for_acks_.size(); | 
 |   } | 
 | } | 
 |  | 
 | QuicStream* QuicSession::GetStream(QuicStreamId id) const { | 
 |   auto active_stream = stream_map_.find(id); | 
 |   if (active_stream != stream_map_.end()) { | 
 |     return active_stream->second.get(); | 
 |   } | 
 |   auto zombie_stream = zombie_streams_.find(id); | 
 |   if (zombie_stream != zombie_streams_.end()) { | 
 |     return zombie_stream->second.get(); | 
 |   } | 
 |  | 
 |   if (QuicUtils::IsCryptoStreamId(connection_->transport_version(), id)) { | 
 |     return const_cast<QuicCryptoStream*>(GetCryptoStream()); | 
 |   } | 
 |  | 
 |   return nullptr; | 
 | } | 
 |  | 
 | bool QuicSession::OnFrameAcked(const QuicFrame& frame, | 
 |                                QuicTime::Delta ack_delay_time, | 
 |                                QuicTime receive_timestamp) { | 
 |   if (frame.type == MESSAGE_FRAME) { | 
 |     OnMessageAcked(frame.message_frame->message_id, receive_timestamp); | 
 |     return true; | 
 |   } | 
 |   if (frame.type == CRYPTO_FRAME) { | 
 |     return GetMutableCryptoStream()->OnCryptoFrameAcked(*frame.crypto_frame, | 
 |                                                         ack_delay_time); | 
 |   } | 
 |   if (frame.type != STREAM_FRAME) { | 
 |     return control_frame_manager_.OnControlFrameAcked(frame); | 
 |   } | 
 |   bool new_stream_data_acked = false; | 
 |   QuicStream* stream = GetStream(frame.stream_frame.stream_id); | 
 |   // Stream can already be reset when sent frame gets acked. | 
 |   if (stream != nullptr) { | 
 |     QuicByteCount newly_acked_length = 0; | 
 |     new_stream_data_acked = stream->OnStreamFrameAcked( | 
 |         frame.stream_frame.offset, frame.stream_frame.data_length, | 
 |         frame.stream_frame.fin, ack_delay_time, &newly_acked_length); | 
 |     if (!stream->HasPendingRetransmission()) { | 
 |       streams_with_pending_retransmission_.erase(stream->id()); | 
 |     } | 
 |   } | 
 |   return new_stream_data_acked; | 
 | } | 
 |  | 
 | void QuicSession::OnStreamFrameRetransmitted(const QuicStreamFrame& frame) { | 
 |   QuicStream* stream = GetStream(frame.stream_id); | 
 |   if (stream == nullptr) { | 
 |     QUIC_BUG << "Stream: " << frame.stream_id << " is closed when " << frame | 
 |              << " is retransmitted."; | 
 |     connection()->CloseConnection( | 
 |         QUIC_INTERNAL_ERROR, "Attempt to retransmit frame of a closed stream", | 
 |         ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     return; | 
 |   } | 
 |   stream->OnStreamFrameRetransmitted(frame.offset, frame.data_length, | 
 |                                      frame.fin); | 
 | } | 
 |  | 
 | void QuicSession::OnFrameLost(const QuicFrame& frame) { | 
 |   if (frame.type == MESSAGE_FRAME) { | 
 |     OnMessageLost(frame.message_frame->message_id); | 
 |     return; | 
 |   } | 
 |   if (frame.type == CRYPTO_FRAME) { | 
 |     GetMutableCryptoStream()->OnCryptoFrameLost(frame.crypto_frame); | 
 |     return; | 
 |   } | 
 |   if (frame.type != STREAM_FRAME) { | 
 |     control_frame_manager_.OnControlFrameLost(frame); | 
 |     return; | 
 |   } | 
 |   QuicStream* stream = GetStream(frame.stream_frame.stream_id); | 
 |   if (stream == nullptr) { | 
 |     return; | 
 |   } | 
 |   stream->OnStreamFrameLost(frame.stream_frame.offset, | 
 |                             frame.stream_frame.data_length, | 
 |                             frame.stream_frame.fin); | 
 |   if (stream->HasPendingRetransmission() && | 
 |       !QuicContainsKey(streams_with_pending_retransmission_, | 
 |                        frame.stream_frame.stream_id)) { | 
 |     streams_with_pending_retransmission_.insert( | 
 |         std::make_pair(frame.stream_frame.stream_id, true)); | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::RetransmitFrames(const QuicFrames& frames, | 
 |                                    TransmissionType type) { | 
 |   QuicConnection::ScopedPacketFlusher retransmission_flusher(connection_); | 
 |   SetTransmissionType(type); | 
 |   for (const QuicFrame& frame : frames) { | 
 |     if (frame.type == MESSAGE_FRAME) { | 
 |       // Do not retransmit MESSAGE frames. | 
 |       continue; | 
 |     } | 
 |     if (frame.type == CRYPTO_FRAME) { | 
 |       GetMutableCryptoStream()->RetransmitData(frame.crypto_frame); | 
 |       continue; | 
 |     } | 
 |     if (frame.type != STREAM_FRAME) { | 
 |       if (!control_frame_manager_.RetransmitControlFrame(frame)) { | 
 |         break; | 
 |       } | 
 |       continue; | 
 |     } | 
 |     QuicStream* stream = GetStream(frame.stream_frame.stream_id); | 
 |     if (stream != nullptr && | 
 |         !stream->RetransmitStreamData(frame.stream_frame.offset, | 
 |                                       frame.stream_frame.data_length, | 
 |                                       frame.stream_frame.fin)) { | 
 |       break; | 
 |     } | 
 |   } | 
 | } | 
 |  | 
 | bool QuicSession::IsFrameOutstanding(const QuicFrame& frame) const { | 
 |   if (frame.type == MESSAGE_FRAME) { | 
 |     return false; | 
 |   } | 
 |   if (frame.type == CRYPTO_FRAME) { | 
 |     return GetCryptoStream()->IsFrameOutstanding( | 
 |         frame.crypto_frame->level, frame.crypto_frame->offset, | 
 |         frame.crypto_frame->data_length); | 
 |   } | 
 |   if (frame.type != STREAM_FRAME) { | 
 |     return control_frame_manager_.IsControlFrameOutstanding(frame); | 
 |   } | 
 |   QuicStream* stream = GetStream(frame.stream_frame.stream_id); | 
 |   return stream != nullptr && | 
 |          stream->IsStreamFrameOutstanding(frame.stream_frame.offset, | 
 |                                           frame.stream_frame.data_length, | 
 |                                           frame.stream_frame.fin); | 
 | } | 
 |  | 
 | bool QuicSession::HasUnackedCryptoData() const { | 
 |   const QuicCryptoStream* crypto_stream = GetCryptoStream(); | 
 |   return crypto_stream->IsWaitingForAcks() || crypto_stream->HasBufferedData(); | 
 | } | 
 |  | 
 | bool QuicSession::HasUnackedStreamData() const { | 
 |   DCHECK(ignore_tlpr_if_no_pending_stream_data()); | 
 |   if (ignore_tlpr_if_no_pending_stream_data()) { | 
 |     QUIC_RELOADABLE_FLAG_COUNT_N(quic_ignore_tlpr_if_no_pending_stream_data, 5, | 
 |                                  5); | 
 |     return !streams_waiting_for_acks_.empty(); | 
 |   } | 
 |  | 
 |   return true; | 
 | } | 
 |  | 
 | WriteStreamDataResult QuicSession::WriteStreamData(QuicStreamId id, | 
 |                                                    QuicStreamOffset offset, | 
 |                                                    QuicByteCount data_length, | 
 |                                                    QuicDataWriter* writer) { | 
 |   QuicStream* stream = GetStream(id); | 
 |   if (stream == nullptr) { | 
 |     // This causes the connection to be closed because of failed to serialize | 
 |     // packet. | 
 |     QUIC_BUG << "Stream " << id << " does not exist when trying to write data." | 
 |              << " version:" << connection_->transport_version(); | 
 |     return STREAM_MISSING; | 
 |   } | 
 |   if (stream->WriteStreamData(offset, data_length, writer)) { | 
 |     return WRITE_SUCCESS; | 
 |   } | 
 |   return WRITE_FAILED; | 
 | } | 
 |  | 
 | bool QuicSession::WriteCryptoData(EncryptionLevel level, | 
 |                                   QuicStreamOffset offset, | 
 |                                   QuicByteCount data_length, | 
 |                                   QuicDataWriter* writer) { | 
 |   return GetMutableCryptoStream()->WriteCryptoFrame(level, offset, data_length, | 
 |                                                     writer); | 
 | } | 
 |  | 
 | QuicUint128 QuicSession::GetStatelessResetToken() const { | 
 |   return QuicUtils::GenerateStatelessResetToken(connection_->connection_id()); | 
 | } | 
 |  | 
 | bool QuicSession::RetransmitLostData() { | 
 |   QuicConnection::ScopedPacketFlusher retransmission_flusher(connection_); | 
 |   // Retransmit crypto data first. | 
 |   bool uses_crypto_frames = | 
 |       QuicVersionUsesCryptoFrames(connection_->transport_version()); | 
 |   QuicCryptoStream* crypto_stream = GetMutableCryptoStream(); | 
 |   if (uses_crypto_frames && crypto_stream->HasPendingCryptoRetransmission()) { | 
 |     SetTransmissionType(HANDSHAKE_RETRANSMISSION); | 
 |     crypto_stream->WritePendingCryptoRetransmission(); | 
 |   } | 
 |   // Retransmit crypto data in stream 1 frames (version < 47). | 
 |   if (!uses_crypto_frames && | 
 |       QuicContainsKey( | 
 |           streams_with_pending_retransmission_, | 
 |           QuicUtils::GetCryptoStreamId(connection_->transport_version()))) { | 
 |     SetTransmissionType(HANDSHAKE_RETRANSMISSION); | 
 |     // Retransmit crypto data first. | 
 |     QuicStream* crypto_stream = GetStream( | 
 |         QuicUtils::GetCryptoStreamId(connection_->transport_version())); | 
 |     crypto_stream->OnCanWrite(); | 
 |     DCHECK(CheckStreamWriteBlocked(crypto_stream)); | 
 |     if (crypto_stream->HasPendingRetransmission()) { | 
 |       // Connection is write blocked. | 
 |       return false; | 
 |     } else { | 
 |       streams_with_pending_retransmission_.erase( | 
 |           QuicUtils::GetCryptoStreamId(connection_->transport_version())); | 
 |     } | 
 |   } | 
 |   if (control_frame_manager_.HasPendingRetransmission()) { | 
 |     SetTransmissionType(LOSS_RETRANSMISSION); | 
 |     control_frame_manager_.OnCanWrite(); | 
 |     if (control_frame_manager_.HasPendingRetransmission()) { | 
 |       return false; | 
 |     } | 
 |   } | 
 |   while (!streams_with_pending_retransmission_.empty()) { | 
 |     if (!connection_->CanWriteStreamData()) { | 
 |       break; | 
 |     } | 
 |     // Retransmit lost data on headers and data streams. | 
 |     const QuicStreamId id = streams_with_pending_retransmission_.begin()->first; | 
 |     QuicStream* stream = GetStream(id); | 
 |     if (stream != nullptr) { | 
 |       SetTransmissionType(LOSS_RETRANSMISSION); | 
 |       stream->OnCanWrite(); | 
 |       DCHECK(CheckStreamWriteBlocked(stream)); | 
 |       if (stream->HasPendingRetransmission()) { | 
 |         // Connection is write blocked. | 
 |         break; | 
 |       } else if (!streams_with_pending_retransmission_.empty() && | 
 |                  streams_with_pending_retransmission_.begin()->first == id) { | 
 |         // Retransmit lost data may cause connection close. If this stream | 
 |         // has not yet sent fin, a RST_STREAM will be sent and it will be | 
 |         // removed from streams_with_pending_retransmission_. | 
 |         streams_with_pending_retransmission_.pop_front(); | 
 |       } | 
 |     } else { | 
 |       QUIC_BUG << "Try to retransmit data of a closed stream"; | 
 |       streams_with_pending_retransmission_.pop_front(); | 
 |     } | 
 |   } | 
 |  | 
 |   return streams_with_pending_retransmission_.empty(); | 
 | } | 
 |  | 
 | void QuicSession::NeuterUnencryptedData() { | 
 |   if (connection_->session_decides_what_to_write()) { | 
 |     QuicCryptoStream* crypto_stream = GetMutableCryptoStream(); | 
 |     crypto_stream->NeuterUnencryptedStreamData(); | 
 |     if (!crypto_stream->HasPendingRetransmission() && | 
 |         !QuicVersionUsesCryptoFrames(connection_->transport_version())) { | 
 |       streams_with_pending_retransmission_.erase( | 
 |           QuicUtils::GetCryptoStreamId(connection_->transport_version())); | 
 |     } | 
 |   } | 
 |   connection_->NeuterUnencryptedPackets(); | 
 | } | 
 |  | 
 | void QuicSession::SetTransmissionType(TransmissionType type) { | 
 |   connection_->SetTransmissionType(type); | 
 | } | 
 |  | 
 | MessageResult QuicSession::SendMessage(QuicMemSliceSpan message) { | 
 |   if (!IsEncryptionEstablished()) { | 
 |     return {MESSAGE_STATUS_ENCRYPTION_NOT_ESTABLISHED, 0}; | 
 |   } | 
 |   MessageStatus result = | 
 |       connection_->SendMessage(last_message_id_ + 1, message); | 
 |   if (result == MESSAGE_STATUS_SUCCESS) { | 
 |     return {result, ++last_message_id_}; | 
 |   } | 
 |   return {result, 0}; | 
 | } | 
 |  | 
 | void QuicSession::OnMessageAcked(QuicMessageId message_id, | 
 |                                  QuicTime /*receive_timestamp*/) { | 
 |   QUIC_DVLOG(1) << ENDPOINT << "message " << message_id << " gets acked."; | 
 | } | 
 |  | 
 | void QuicSession::OnMessageLost(QuicMessageId message_id) { | 
 |   QUIC_DVLOG(1) << ENDPOINT << "message " << message_id | 
 |                 << " is considered lost"; | 
 | } | 
 |  | 
 | void QuicSession::CleanUpClosedStreams() { | 
 |   closed_streams_.clear(); | 
 | } | 
 |  | 
 | bool QuicSession::session_decides_what_to_write() const { | 
 |   return connection_->session_decides_what_to_write(); | 
 | } | 
 |  | 
 | QuicPacketLength QuicSession::GetCurrentLargestMessagePayload() const { | 
 |   return connection_->GetCurrentLargestMessagePayload(); | 
 | } | 
 |  | 
 | QuicPacketLength QuicSession::GetGuaranteedLargestMessagePayload() const { | 
 |   return connection_->GetGuaranteedLargestMessagePayload(); | 
 | } | 
 |  | 
 | void QuicSession::SendStopSending(uint16_t code, QuicStreamId stream_id) { | 
 |   control_frame_manager_.WriteOrBufferStopSending(code, stream_id); | 
 | } | 
 |  | 
 | void QuicSession::OnCanCreateNewOutgoingStream(bool /*unidirectional*/) {} | 
 |  | 
 | QuicStreamId QuicSession::next_outgoing_bidirectional_stream_id() const { | 
 |   if (VersionHasIetfQuicFrames(connection_->transport_version())) { | 
 |     return v99_streamid_manager_.next_outgoing_bidirectional_stream_id(); | 
 |   } | 
 |   return stream_id_manager_.next_outgoing_stream_id(); | 
 | } | 
 |  | 
 | QuicStreamId QuicSession::next_outgoing_unidirectional_stream_id() const { | 
 |   if (VersionHasIetfQuicFrames(connection_->transport_version())) { | 
 |     return v99_streamid_manager_.next_outgoing_unidirectional_stream_id(); | 
 |   } | 
 |   return stream_id_manager_.next_outgoing_stream_id(); | 
 | } | 
 |  | 
 | bool QuicSession::OnMaxStreamsFrame(const QuicMaxStreamsFrame& frame) { | 
 |   return v99_streamid_manager_.OnMaxStreamsFrame(frame); | 
 | } | 
 |  | 
 | bool QuicSession::OnStreamsBlockedFrame(const QuicStreamsBlockedFrame& frame) { | 
 |   return v99_streamid_manager_.OnStreamsBlockedFrame(frame); | 
 | } | 
 |  | 
 | size_t QuicSession::max_open_incoming_bidirectional_streams() const { | 
 |   if (VersionHasIetfQuicFrames(connection_->transport_version())) { | 
 |     return v99_streamid_manager_.GetMaxAllowdIncomingBidirectionalStreams(); | 
 |   } | 
 |   return stream_id_manager_.max_open_incoming_streams(); | 
 | } | 
 |  | 
 | size_t QuicSession::max_open_incoming_unidirectional_streams() const { | 
 |   if (VersionHasIetfQuicFrames(connection_->transport_version())) { | 
 |     return v99_streamid_manager_.GetMaxAllowdIncomingUnidirectionalStreams(); | 
 |   } | 
 |   return stream_id_manager_.max_open_incoming_streams(); | 
 | } | 
 |  | 
 | #undef ENDPOINT  // undef for jumbo builds | 
 | }  // namespace quic |