| // 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 "quiche/quic/core/quic_session.h" | 
 |  | 
 | #include <algorithm> | 
 | #include <cstdint> | 
 | #include <limits> | 
 | #include <memory> | 
 | #include <optional> | 
 | #include <ostream> | 
 | #include <sstream> | 
 | #include <string> | 
 | #include <utility> | 
 | #include <vector> | 
 |  | 
 | #include "absl/memory/memory.h" | 
 | #include "absl/strings/str_cat.h" | 
 | #include "absl/strings/string_view.h" | 
 | #include "quiche/quic/core/crypto/crypto_protocol.h" | 
 | #include "quiche/quic/core/frames/quic_ack_frequency_frame.h" | 
 | #include "quiche/quic/core/frames/quic_reset_stream_at_frame.h" | 
 | #include "quiche/quic/core/frames/quic_window_update_frame.h" | 
 | #include "quiche/quic/core/quic_connection.h" | 
 | #include "quiche/quic/core/quic_connection_context.h" | 
 | #include "quiche/quic/core/quic_constants.h" | 
 | #include "quiche/quic/core/quic_error_codes.h" | 
 | #include "quiche/quic/core/quic_flow_controller.h" | 
 | #include "quiche/quic/core/quic_stream.h" | 
 | #include "quiche/quic/core/quic_stream_priority.h" | 
 | #include "quiche/quic/core/quic_types.h" | 
 | #include "quiche/quic/core/quic_utils.h" | 
 | #include "quiche/quic/core/quic_versions.h" | 
 | #include "quiche/quic/core/quic_write_blocked_list.h" | 
 | #include "quiche/quic/core/web_transport_write_blocked_list.h" | 
 | #include "quiche/quic/platform/api/quic_bug_tracker.h" | 
 | #include "quiche/quic/platform/api/quic_flag_utils.h" | 
 | #include "quiche/quic/platform/api/quic_flags.h" | 
 | #include "quiche/quic/platform/api/quic_logging.h" | 
 | #include "quiche/quic/platform/api/quic_server_stats.h" | 
 | #include "quiche/common/platform/api/quiche_logging.h" | 
 | #include "quiche/common/quiche_callbacks.h" | 
 | #include "quiche/common/quiche_text_utils.h" | 
 |  | 
 | namespace quic { | 
 |  | 
 | namespace { | 
 |  | 
 | class ClosedStreamsCleanUpDelegate : public QuicAlarm::Delegate { | 
 |  public: | 
 |   explicit ClosedStreamsCleanUpDelegate(QuicSession* session) | 
 |       : session_(session) {} | 
 |   ClosedStreamsCleanUpDelegate(const ClosedStreamsCleanUpDelegate&) = delete; | 
 |   ClosedStreamsCleanUpDelegate& operator=(const ClosedStreamsCleanUpDelegate&) = | 
 |       delete; | 
 |  | 
 |   QuicConnectionContext* GetConnectionContext() override { | 
 |     return (session_->connection() == nullptr) | 
 |                ? nullptr | 
 |                : session_->connection()->context(); | 
 |   } | 
 |  | 
 |   void OnAlarm() override { session_->CleanUpClosedStreams(); } | 
 |  | 
 |  private: | 
 |   QuicSession* session_; | 
 | }; | 
 |  | 
 | class StreamCountResetAlarmDelegate : public QuicAlarm::Delegate { | 
 |  public: | 
 |   explicit StreamCountResetAlarmDelegate(QuicSession* session) | 
 |       : session_(session) {} | 
 |   StreamCountResetAlarmDelegate(const StreamCountResetAlarmDelegate&) = delete; | 
 |   StreamCountResetAlarmDelegate& operator=( | 
 |       const StreamCountResetAlarmDelegate&) = delete; | 
 |  | 
 |   QuicConnectionContext* GetConnectionContext() override { | 
 |     return (session_->connection() == nullptr) | 
 |                ? nullptr | 
 |                : session_->connection()->context(); | 
 |   } | 
 |  | 
 |   void OnAlarm() override { session_->OnStreamCountReset(); } | 
 |  | 
 |  private: | 
 |   QuicSession* session_; | 
 | }; | 
 |  | 
 | std::unique_ptr<QuicWriteBlockedListInterface> CreateWriteBlockedList( | 
 |     QuicPriorityType priority_type) { | 
 |   switch (priority_type) { | 
 |     case QuicPriorityType::kHttp: | 
 |       return std::make_unique<QuicWriteBlockedList>(); | 
 |     case QuicPriorityType::kWebTransport: | 
 |       return std::make_unique<WebTransportWriteBlockedList>(); | 
 |   } | 
 |   QUICHE_NOTREACHED(); | 
 |   return nullptr; | 
 | } | 
 |  | 
 | }  // namespace | 
 |  | 
 | #define ENDPOINT \ | 
 |   (perspective() == Perspective::IS_SERVER ? "Server: " : "Client: ") | 
 |  | 
 | QuicSession::QuicSession( | 
 |     QuicConnection* connection, Visitor* owner, const QuicConfig& config, | 
 |     const ParsedQuicVersionVector& supported_versions, | 
 |     QuicStreamCount num_expected_unidirectional_static_streams) | 
 |     : QuicSession(connection, owner, config, supported_versions, | 
 |                   num_expected_unidirectional_static_streams, nullptr) {} | 
 |  | 
 | QuicSession::QuicSession( | 
 |     QuicConnection* connection, Visitor* owner, const QuicConfig& config, | 
 |     const ParsedQuicVersionVector& supported_versions, | 
 |     QuicStreamCount num_expected_unidirectional_static_streams, | 
 |     std::unique_ptr<QuicDatagramQueue::Observer> datagram_observer, | 
 |     QuicPriorityType priority_type) | 
 |     : connection_(connection), | 
 |       perspective_(connection->perspective()), | 
 |       visitor_(owner), | 
 |       write_blocked_streams_(CreateWriteBlockedList(priority_type)), | 
 |       config_(config), | 
 |       stream_id_manager_(perspective(), connection->transport_version(), | 
 |                          kDefaultMaxStreamsPerConnection, | 
 |                          config_.GetMaxBidirectionalStreamsToSend()), | 
 |       ietf_streamid_manager_(perspective(), connection->version(), this, 0, | 
 |                              num_expected_unidirectional_static_streams, | 
 |                              config_.GetMaxBidirectionalStreamsToSend(), | 
 |                              config_.GetMaxUnidirectionalStreamsToSend() + | 
 |                                  num_expected_unidirectional_static_streams), | 
 |       num_draining_streams_(0), | 
 |       num_outgoing_draining_streams_(0), | 
 |       num_static_streams_(0), | 
 |       num_zombie_streams_(0), | 
 |       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), | 
 |       transport_goaway_sent_(false), | 
 |       transport_goaway_received_(false), | 
 |       control_frame_manager_(this), | 
 |       last_message_id_(0), | 
 |       datagram_queue_(this, std::move(datagram_observer)), | 
 |       closed_streams_clean_up_alarm_(nullptr), | 
 |       supported_versions_(supported_versions), | 
 |       is_configured_(false), | 
 |       was_zero_rtt_rejected_(false), | 
 |       liveness_testing_in_progress_(false), | 
 |       stream_count_reset_alarm_( | 
 |           absl::WrapUnique<QuicAlarm>(connection->alarm_factory()->CreateAlarm( | 
 |               new StreamCountResetAlarmDelegate(this)))), | 
 |       priority_type_(priority_type) { | 
 |   closed_streams_clean_up_alarm_ = | 
 |       absl::WrapUnique<QuicAlarm>(connection_->alarm_factory()->CreateAlarm( | 
 |           new ClosedStreamsCleanUpDelegate(this))); | 
 |   if (VersionHasIetfQuicFrames(transport_version())) { | 
 |     config_.SetMaxUnidirectionalStreamsToSend( | 
 |         config_.GetMaxUnidirectionalStreamsToSend() + | 
 |         num_expected_unidirectional_static_streams); | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::Initialize() { | 
 |   connection_->set_visitor(this); | 
 |   connection_->SetSessionNotifier(this); | 
 |   connection_->SetDataProducer(this); | 
 |   connection_->SetUnackedMapInitialCapacity(); | 
 |   if (perspective_ == Perspective::IS_CLIENT) { | 
 |     if (config_.HasClientSentConnectionOption(kCHP1, perspective_)) { | 
 |       config_.SetDiscardLengthToSend(kDefaultMaxPacketSize); | 
 |     } else if (config_.HasClientSentConnectionOption(kCHP2, perspective_)) { | 
 |       config_.SetDiscardLengthToSend(kDefaultMaxPacketSize * 2); | 
 |     } | 
 |   } else if (GetQuicReloadableFlag(quic_receive_ack_frequency) && | 
 |              connection_->version().HasIetfQuicFrames()) { | 
 |     config_.SetMinAckDelayDraft10Ms(kDefaultMinAckDelayTimeMs); | 
 |   } | 
 |   connection_->SetFromConfig(config_); | 
 |   if (perspective() == Perspective::IS_SERVER && | 
 |       connection_->version().handshake_protocol == PROTOCOL_TLS1_3) { | 
 |     config_.SetStatelessResetTokenToSend(GetStatelessResetToken()); | 
 |   } | 
 |  | 
 |   connection_->CreateConnectionIdManager(); | 
 |  | 
 |   // On the server side, version negotiation has been done by the dispatcher, | 
 |   // and the server session is created with the right version. | 
 |   if (perspective() == Perspective::IS_SERVER) { | 
 |     connection_->OnSuccessfulVersionNegotiation(); | 
 |   } | 
 |  | 
 |   if (QuicVersionUsesCryptoFrames(transport_version())) { | 
 |     return; | 
 |   } | 
 |  | 
 |   QUICHE_DCHECK_EQ(QuicUtils::GetCryptoStreamId(transport_version()), | 
 |                    GetMutableCryptoStream()->id()); | 
 | } | 
 |  | 
 | QuicSession::~QuicSession() { | 
 |   if (closed_streams_clean_up_alarm_ != nullptr) { | 
 |     closed_streams_clean_up_alarm_->PermanentCancel(); | 
 |   } | 
 |   if (stream_count_reset_alarm_ != nullptr) { | 
 |     stream_count_reset_alarm_->PermanentCancel(); | 
 |   } | 
 | } | 
 |  | 
 | PendingStream* QuicSession::PendingStreamOnStreamFrame( | 
 |     const QuicStreamFrame& frame) { | 
 |   QUICHE_DCHECK(VersionUsesHttp3(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 nullptr; | 
 |   } | 
 |  | 
 |   pending->OnStreamFrame(frame); | 
 |   if (!connection()->connected()) { | 
 |     return nullptr; | 
 |   } | 
 |   return pending; | 
 | } | 
 |  | 
 | bool QuicSession::MaybeProcessPendingStream(PendingStream* pending) { | 
 |   QUICHE_DCHECK(pending != nullptr && connection()->connected()); | 
 |  | 
 |   if (ExceedsPerLoopStreamLimit()) { | 
 |     QUIC_DLOG(INFO) << "Skip processing pending stream " << pending->id() | 
 |                     << " because it exceeds per loop limit."; | 
 |     QUIC_CODE_COUNT_N(quic_pending_stream, 1, 3); | 
 |     return false; | 
 |   } | 
 |  | 
 |   QuicStreamId stream_id = pending->id(); | 
 |   std::optional<QuicResetStreamError> stop_sending_error_code = | 
 |       pending->GetStopSendingErrorCode(); | 
 |   QUIC_DLOG(INFO) << "Process pending stream " << pending->id(); | 
 |   QuicStream* stream = ProcessPendingStream(pending); | 
 |   if (stream != nullptr) { | 
 |     // The pending stream should now be in the scope of normal streams. | 
 |     QUICHE_DCHECK(IsClosedStream(stream_id) || IsOpenStream(stream_id)) | 
 |         << "Stream " << stream_id << " not created"; | 
 |     if (!stream->pending_duration().IsZero()) { | 
 |       QUIC_SERVER_HISTOGRAM_TIMES("QuicStream.PendingDurationUs", | 
 |                                   stream->pending_duration().ToMicroseconds(), | 
 |                                   0, 1000 * 100, 20, | 
 |                                   "Time a stream has been pending at server."); | 
 |       ++connection()->mutable_stats().num_total_pending_streams; | 
 |     } | 
 |     pending_stream_map_.erase(stream_id); | 
 |     if (stop_sending_error_code) { | 
 |       stream->OnStopSending(*stop_sending_error_code); | 
 |       if (!connection()->connected()) { | 
 |         return false; | 
 |       } | 
 |     } | 
 |     stream->OnStreamCreatedFromPendingStream(); | 
 |     return connection()->connected(); | 
 |   } | 
 |   // At this point, none of the bytes has been successfully consumed by the | 
 |   // application layer. We should close the pending stream even if it is | 
 |   // bidirectionl as no application will be able to write in a bidirectional | 
 |   // stream with zero byte as input. | 
 |   if (pending->sequencer()->IsClosed()) { | 
 |     ClosePendingStream(stream_id); | 
 |   } | 
 |   return connection()->connected(); | 
 | } | 
 |  | 
 | void QuicSession::PendingStreamOnWindowUpdateFrame( | 
 |     const QuicWindowUpdateFrame& frame) { | 
 |   QUICHE_DCHECK(VersionUsesHttp3(transport_version())); | 
 |   PendingStream* pending = GetOrCreatePendingStream(frame.stream_id); | 
 |   if (pending) { | 
 |     pending->OnWindowUpdateFrame(frame); | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::PendingStreamOnStopSendingFrame( | 
 |     const QuicStopSendingFrame& frame) { | 
 |   QUICHE_DCHECK(VersionUsesHttp3(transport_version())); | 
 |   PendingStream* pending = GetOrCreatePendingStream(frame.stream_id); | 
 |   if (pending) { | 
 |     pending->OnStopSending(frame.error()); | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::OnStreamFrame(const QuicStreamFrame& frame) { | 
 |   QuicStreamId stream_id = frame.stream_id; | 
 |   if (stream_id == QuicUtils::GetInvalidStreamId(transport_version())) { | 
 |     connection()->CloseConnection( | 
 |         QUIC_INVALID_STREAM_ID, "Received data for an invalid stream", | 
 |         ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     return; | 
 |   } | 
 |  | 
 |   if (ShouldProcessFrameByPendingStream(STREAM_FRAME, stream_id)) { | 
 |     PendingStream* pending = PendingStreamOnStreamFrame(frame); | 
 |     if (pending != nullptr && IsEncryptionEstablished()) { | 
 |       MaybeProcessPendingStream(pending); | 
 |     } | 
 |     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; | 
 |   } | 
 |   stream->OnStreamFrame(frame); | 
 | } | 
 |  | 
 | void QuicSession::OnCryptoFrame(const QuicCryptoFrame& frame) { | 
 |   GetMutableCryptoStream()->OnCryptoFrame(frame); | 
 | } | 
 |  | 
 | void QuicSession::OnStopSendingFrame(const QuicStopSendingFrame& frame) { | 
 |   // STOP_SENDING is in IETF QUIC only. | 
 |   QUICHE_DCHECK(VersionHasIetfQuicFrames(transport_version())); | 
 |   QUICHE_DCHECK(QuicVersionUsesCryptoFrames(transport_version())); | 
 |  | 
 |   QuicStreamId stream_id = frame.stream_id; | 
 |   // If Stream ID is invalid then close the connection. | 
 |   // TODO(ianswett): This check is redundant to checks for IsClosedStream, | 
 |   // but removing it requires removing multiple QUICHE_DCHECKs. | 
 |   // TODO(ianswett): Multiple QUIC_DVLOGs could be QUIC_PEER_BUGs. | 
 |   if (stream_id == QuicUtils::GetInvalidStreamId(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; | 
 |   } | 
 |  | 
 |   // If stream_id is READ_UNIDIRECTIONAL, close the connection. | 
 |   if (QuicUtils::GetStreamType(stream_id, perspective(), | 
 |                                IsIncomingStream(stream_id), | 
 |                                version()) == READ_UNIDIRECTIONAL) { | 
 |     QUIC_DVLOG(1) << ENDPOINT | 
 |                   << "Received STOP_SENDING for a read-only stream_id: " | 
 |                   << stream_id << "."; | 
 |     connection()->CloseConnection( | 
 |         QUIC_INVALID_STREAM_ID, "Received STOP_SENDING for a read-only stream", | 
 |         ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     return; | 
 |   } | 
 |  | 
 |   if (visitor_) { | 
 |     visitor_->OnStopSendingReceived(frame); | 
 |   } | 
 |   if (ShouldProcessFrameByPendingStream(STOP_SENDING_FRAME, stream_id)) { | 
 |     PendingStreamOnStopSendingFrame(frame); | 
 |     return; | 
 |   } | 
 |  | 
 |   QuicStream* stream = nullptr; | 
 |   if (enable_stop_sending_for_zombie_streams_) { | 
 |     stream = GetStream(stream_id); | 
 |     if (stream != nullptr) { | 
 |       if (stream->IsZombie()) { | 
 |         QUIC_RELOADABLE_FLAG_COUNT_N( | 
 |             quic_deliver_stop_sending_to_zombie_streams, 1, 3); | 
 |       } else { | 
 |         QUIC_RELOADABLE_FLAG_COUNT_N( | 
 |             quic_deliver_stop_sending_to_zombie_streams, 2, 3); | 
 |       } | 
 |       stream->OnStopSending(frame.error()); | 
 |       return; | 
 |     } | 
 |   } | 
 |   stream = GetOrCreateStream(stream_id); | 
 |   if (!stream) { | 
 |     // Errors are handled by GetOrCreateStream. | 
 |     return; | 
 |   } | 
 |  | 
 |   stream->OnStopSending(frame.error()); | 
 | } | 
 |  | 
 | void QuicSession::OnPacketDecrypted(EncryptionLevel level) { | 
 |   GetMutableCryptoStream()->OnPacketDecrypted(level); | 
 |   if (liveness_testing_in_progress_) { | 
 |     liveness_testing_in_progress_ = false; | 
 |     OnCanCreateNewOutgoingStream(/*unidirectional=*/false); | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::OnOneRttPacketAcknowledged() { | 
 |   GetMutableCryptoStream()->OnOneRttPacketAcknowledged(); | 
 | } | 
 |  | 
 | void QuicSession::OnHandshakePacketSent() { | 
 |   GetMutableCryptoStream()->OnHandshakePacketSent(); | 
 | } | 
 |  | 
 | std::unique_ptr<QuicDecrypter> | 
 | QuicSession::AdvanceKeysAndCreateCurrentOneRttDecrypter() { | 
 |   return GetMutableCryptoStream()->AdvanceKeysAndCreateCurrentOneRttDecrypter(); | 
 | } | 
 |  | 
 | std::unique_ptr<QuicEncrypter> QuicSession::CreateCurrentOneRttEncrypter() { | 
 |   return GetMutableCryptoStream()->CreateCurrentOneRttEncrypter(); | 
 | } | 
 |  | 
 | void QuicSession::PendingStreamOnRstStream(const QuicRstStreamFrame& frame) { | 
 |   QUICHE_DCHECK(VersionUsesHttp3(transport_version())); | 
 |   QuicStreamId stream_id = frame.stream_id; | 
 |  | 
 |   PendingStream* pending = GetOrCreatePendingStream(stream_id); | 
 |  | 
 |   if (!pending) { | 
 |     HandleRstOnValidNonexistentStream(frame); | 
 |     return; | 
 |   } | 
 |  | 
 |   pending->OnRstStreamFrame(frame); | 
 |   // At this point, none of the bytes has been consumed by the application | 
 |   // layer. It is safe to close the pending stream even if it is bidirectionl as | 
 |   // no application will be able to write in a bidirectional stream with zero | 
 |   // byte as input. | 
 |   ClosePendingStream(stream_id); | 
 | } | 
 |  | 
 | void QuicSession::PendingStreamOnResetStreamAt( | 
 |     const QuicResetStreamAtFrame& frame) { | 
 |   QUICHE_DCHECK(VersionUsesHttp3(transport_version())); | 
 |   QuicStreamId stream_id = frame.stream_id; | 
 |  | 
 |   PendingStream* pending = GetOrCreatePendingStream(stream_id); | 
 |  | 
 |   if (!pending) { | 
 |     HandleRstOnValidNonexistentStream(frame.ToRstStream()); | 
 |     return; | 
 |   } | 
 |  | 
 |   pending->OnResetStreamAtFrame(frame); | 
 | } | 
 |  | 
 | void QuicSession::OnRstStream(const QuicRstStreamFrame& frame) { | 
 |   QuicStreamId stream_id = frame.stream_id; | 
 |   if (stream_id == QuicUtils::GetInvalidStreamId(transport_version())) { | 
 |     connection()->CloseConnection( | 
 |         QUIC_INVALID_STREAM_ID, "Received data for an invalid stream", | 
 |         ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     return; | 
 |   } | 
 |  | 
 |   if (VersionHasIetfQuicFrames(transport_version()) && | 
 |       QuicUtils::GetStreamType(stream_id, perspective(), | 
 |                                IsIncomingStream(stream_id), | 
 |                                version()) == WRITE_UNIDIRECTIONAL) { | 
 |     connection()->CloseConnection( | 
 |         QUIC_INVALID_STREAM_ID, "Received RESET_STREAM for a write-only stream", | 
 |         ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     return; | 
 |   } | 
 |  | 
 |   if (visitor_) { | 
 |     visitor_->OnRstStreamReceived(frame); | 
 |   } | 
 |  | 
 |   if (ShouldProcessFrameByPendingStream(RST_STREAM_FRAME, stream_id)) { | 
 |     PendingStreamOnRstStream(frame); | 
 |     return; | 
 |   } | 
 |  | 
 |   QuicStream* stream = GetOrCreateStream(stream_id); | 
 |  | 
 |   if (!stream) { | 
 |     HandleRstOnValidNonexistentStream(frame); | 
 |     return;  // Errors are handled by GetOrCreateStream. | 
 |   } | 
 |   stream->OnStreamReset(frame); | 
 | } | 
 |  | 
 | void QuicSession::OnResetStreamAt(const QuicResetStreamAtFrame& frame) { | 
 |   QUICHE_DCHECK(VersionHasIetfQuicFrames(transport_version())); | 
 |   QuicStreamId stream_id = frame.stream_id; | 
 |   if (stream_id == QuicUtils::GetInvalidStreamId(transport_version())) { | 
 |     connection()->CloseConnection( | 
 |         QUIC_INVALID_STREAM_ID, "Received data for an invalid stream", | 
 |         ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     return; | 
 |   } | 
 |  | 
 |   if (VersionHasIetfQuicFrames(transport_version()) && | 
 |       QuicUtils::GetStreamType(stream_id, perspective(), | 
 |                                IsIncomingStream(stream_id), | 
 |                                version()) == WRITE_UNIDIRECTIONAL) { | 
 |     connection()->CloseConnection( | 
 |         QUIC_INVALID_STREAM_ID, "Received RESET_STREAM for a write-only stream", | 
 |         ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     return; | 
 |   } | 
 |  | 
 |   if (ShouldProcessFrameByPendingStream(RESET_STREAM_AT_FRAME, stream_id)) { | 
 |     PendingStreamOnResetStreamAt(frame); | 
 |     return; | 
 |   } | 
 |  | 
 |   QuicStream* stream = GetOrCreateStream(stream_id); | 
 |  | 
 |   if (!stream) { | 
 |     HandleRstOnValidNonexistentStream(frame.ToRstStream()); | 
 |     return;  // Errors are handled by GetOrCreateStream. | 
 |   } | 
 |   stream->OnResetStreamAtFrame(frame); | 
 | } | 
 |  | 
 | void QuicSession::OnGoAway(const QuicGoAwayFrame& /*frame*/) { | 
 |   QUIC_BUG_IF(quic_bug_12435_1, version().UsesHttp3()) | 
 |       << "gQUIC GOAWAY received on version " << version(); | 
 |  | 
 |   transport_goaway_received_ = true; | 
 | } | 
 |  | 
 | void QuicSession::OnMessageReceived(absl::string_view message) { | 
 |   QUIC_DVLOG(1) << ENDPOINT << "Received message of length " | 
 |                 << message.length(); | 
 |   QUIC_DVLOG(2) << ENDPOINT << "Contents of message of length " | 
 |                 << message.length() << ":" << std::endl | 
 |                 << quiche::QuicheTextUtils::HexDump(message); | 
 | } | 
 |  | 
 | void QuicSession::OnHandshakeDoneReceived() { | 
 |   QUIC_DVLOG(1) << ENDPOINT << "OnHandshakeDoneReceived"; | 
 |   GetMutableCryptoStream()->OnHandshakeDoneReceived(); | 
 | } | 
 |  | 
 | void QuicSession::OnNewTokenReceived(absl::string_view token) { | 
 |   QUICHE_DCHECK_EQ(perspective_, Perspective::IS_CLIENT); | 
 |   GetMutableCryptoStream()->OnNewTokenReceived(token); | 
 | } | 
 |  | 
 | // 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) { | 
 |   QUICHE_DCHECK(!connection_->connected()); | 
 |   if (perspective() == Perspective::IS_SERVER) { | 
 |     RecordConnectionCloseAtServer(frame.quic_error_code, source); | 
 |   } | 
 |  | 
 |   if (on_closed_frame_.quic_error_code == QUIC_NO_ERROR) { | 
 |     // Save all of the connection close information | 
 |     on_closed_frame_ = frame; | 
 |     connection_close_source_ = source; | 
 |   } | 
 |  | 
 |   GetMutableCryptoStream()->OnConnectionClosed(frame, source); | 
 |  | 
 |   if (!notify_stream_soon_to_destroy_) { | 
 |     PerformActionOnActiveStreams([this, frame, source](QuicStream* stream) { | 
 |       QuicStreamId id = stream->id(); | 
 |       stream->OnConnectionClosed(frame, source); | 
 |       auto it = stream_map_.find(id); | 
 |       if (it != stream_map_.end()) { | 
 |         QUIC_BUG_IF(quic_bug_12435_2, !it->second->IsZombie()) | 
 |             << ENDPOINT << "Non-zombie stream " << id | 
 |             << " failed to close under OnConnectionClosed"; | 
 |       } | 
 |       return true; | 
 |     }); | 
 |   } else { | 
 |     QUIC_RELOADABLE_FLAG_COUNT_N(quic_notify_stream_soon_to_destroy, 1, 2); | 
 |     PerformActionOnNonStaticStreams([this, frame, source](QuicStream* stream) { | 
 |       QuicStreamId id = stream->id(); | 
 |       stream->OnConnectionClosed(frame, source); | 
 |       QUIC_BUG_IF(quic_bug_12435_12, stream_map_.contains(id)) | 
 |           << ENDPOINT << "Non-static stream " << id | 
 |           << " failed to be moved to closed stream list under " | 
 |              "OnConnectionClosed"; | 
 |       return true; | 
 |     }); | 
 |     QUIC_BUG_IF(zombie_stream_not_ready_for_destruction, | 
 |                 num_zombie_streams_ > 0); | 
 |   } | 
 |  | 
 |   closed_streams_clean_up_alarm_->Cancel(); | 
 |   stream_count_reset_alarm_->Cancel(); | 
 |  | 
 |   if (visitor_) { | 
 |     visitor_->OnConnectionClosed(connection_->GetOneActiveServerConnectionId(), | 
 |                                  frame.quic_error_code, frame.error_details, | 
 |                                  source); | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::PrepareStreamForDestruction(StreamMap::iterator it) { | 
 |   QUIC_BUG_IF(alive_stream_not_in_stream_map, it == stream_map_.end()); | 
 |   it->second->OnSoonToBeDestroyed(); | 
 |   closed_streams_.push_back(std::move(it->second)); | 
 |   stream_map_.erase(it); | 
 | } | 
 |  | 
 | void QuicSession::OnWriteBlocked() { | 
 |   if (!connection_->connected()) { | 
 |     return; | 
 |   } | 
 |   if (visitor_) { | 
 |     visitor_->OnWriteBlocked(connection_); | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::OnSuccessfulVersionNegotiation( | 
 |     const ParsedQuicVersion& /*version*/) {} | 
 |  | 
 | void QuicSession::OnPacketReceived(const QuicSocketAddress& /*self_address*/, | 
 |                                    const QuicSocketAddress& peer_address, | 
 |                                    bool is_connectivity_probe) { | 
 |   QUICHE_DCHECK(!connection_->ignore_gquic_probing()); | 
 |   if (is_connectivity_probe && perspective() == Perspective::IS_SERVER) { | 
 |     // Server only sends back a connectivity probe after received a | 
 |     // connectivity probe from a new peer address. | 
 |     connection_->SendConnectivityProbingPacket(nullptr, peer_address); | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::OnPathDegrading() { | 
 |   if (visitor_) { | 
 |     visitor_->OnPathDegrading(); | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::OnForwardProgressMadeAfterPathDegrading() {} | 
 |  | 
 | void QuicSession::OnForwardProgressMadeAfterFlowLabelChange() {} | 
 |  | 
 | bool QuicSession::AllowSelfAddressChange() const { return false; } | 
 |  | 
 | 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(transport_version())) { | 
 |     // This is a window update that applies to the connection, rather than an | 
 |     // individual stream. | 
 |     QUIC_DVLOG(1) << ENDPOINT | 
 |                   << "Received connection level flow control window " | 
 |                      "update with max data: " | 
 |                   << frame.max_data; | 
 |     flow_controller_.UpdateSendWindowOffset(frame.max_data); | 
 |     return; | 
 |   } | 
 |  | 
 |   if (VersionHasIetfQuicFrames(transport_version()) && | 
 |       QuicUtils::GetStreamType(stream_id, perspective(), | 
 |                                IsIncomingStream(stream_id), | 
 |                                version()) == READ_UNIDIRECTIONAL) { | 
 |     connection()->CloseConnection( | 
 |         QUIC_WINDOW_UPDATE_RECEIVED_ON_READ_UNIDIRECTIONAL_STREAM, | 
 |         "WindowUpdateFrame received on READ_UNIDIRECTIONAL stream.", | 
 |         ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     return; | 
 |   } | 
 |  | 
 |   if (ShouldProcessFrameByPendingStream(WINDOW_UPDATE_FRAME, stream_id)) { | 
 |     PendingStreamOnWindowUpdateFrame(frame); | 
 |     return; | 
 |   } | 
 |  | 
 |   QuicStream* stream = GetOrCreateStream(stream_id); | 
 |   if (stream != nullptr) { | 
 |     stream->OnWindowUpdateFrame(frame); | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::OnBlockedFrame(const QuicBlockedFrame& frame) { | 
 |   QUIC_CODE_COUNT(quic_session_blocked_frame_received); | 
 |   // 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 << ", offset: " << frame.offset; | 
 | } | 
 |  | 
 | 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) << ENDPOINT << "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) << ENDPOINT << "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->IsFlowControlBlocked() && | 
 |       !write_blocked_streams_->IsStreamBlocked(stream->id())) { | 
 |     QUIC_DLOG(ERROR) << ENDPOINT << "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 (connection_->framer().is_processing_packet()) { | 
 |     // Do not write data in the middle of packet processing because rest | 
 |     // frames in the packet may change the data to write. For example, lost | 
 |     // data could be acknowledged. Also, connection is going to emit | 
 |     // OnCanWrite signal post packet processing. | 
 |     QUIC_BUG(session_write_mid_packet_processing) | 
 |         << ENDPOINT << "Try to write mid packet processing."; | 
 |     return; | 
 |   } | 
 |   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; | 
 |   } | 
 |   // 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() && | 
 |       datagram_queue_.empty() && | 
 |       (!QuicVersionUsesCryptoFrames(transport_version()) || | 
 |        !GetCryptoStream()->HasBufferedCryptoFrames())) { | 
 |     return; | 
 |   } | 
 |  | 
 |   QuicConnection::ScopedPacketFlusher flusher(connection_); | 
 |   if (QuicVersionUsesCryptoFrames(transport_version())) { | 
 |     QuicCryptoStream* crypto_stream = GetMutableCryptoStream(); | 
 |     if (crypto_stream->HasBufferedCryptoFrames()) { | 
 |       crypto_stream->WriteBufferedCryptoFrames(); | 
 |     } | 
 |     if ((GetQuicReloadableFlag( | 
 |              quic_no_write_control_frame_upon_connection_close) && | 
 |          !connection_->connected()) || | 
 |         crypto_stream->HasBufferedCryptoFrames()) { | 
 |       if (!connection_->connected()) { | 
 |         QUIC_RELOADABLE_FLAG_COUNT( | 
 |             quic_no_write_control_frame_upon_connection_close); | 
 |       } | 
 |       // Cannot finish writing buffered crypto frames, connection is either | 
 |       // write blocked or closed. | 
 |       return; | 
 |     } | 
 |   } | 
 |   if (control_frame_manager_.WillingToWrite()) { | 
 |     control_frame_manager_.OnCanWrite(); | 
 |   } | 
 |   if (version().UsesTls() && GetHandshakeState() != HANDSHAKE_CONFIRMED && | 
 |       connection_->in_probe_time_out()) { | 
 |     QUIC_CODE_COUNT(quic_donot_pto_stream_data_before_handshake_confirmed); | 
 |     // Do not PTO stream data before handshake gets confirmed. | 
 |     return; | 
 |   } | 
 |   // TODO(b/147146815): this makes all datagrams go before stream data.  We | 
 |   // should have a better priority scheme for this. | 
 |   if (!datagram_queue_.empty()) { | 
 |     size_t written = datagram_queue_.SendDatagrams(); | 
 |     QUIC_DVLOG(1) << ENDPOINT << "Sent " << written << " datagrams"; | 
 |     if (!datagram_queue_.empty()) { | 
 |       return; | 
 |     } | 
 |   } | 
 |   std::vector<QuicStreamId> last_writing_stream_ids; | 
 |   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(quic_bug_10866_1) | 
 |           << "WriteBlockedStream is missing, num_writes: " << num_writes | 
 |           << ", finished_writes: " << i | 
 |           << ", connected: " << connection_->connected() | 
 |           << ", connection level flow control blocked: " | 
 |           << flow_controller_.IsBlocked(); | 
 |       for (QuicStreamId id : last_writing_stream_ids) { | 
 |         QUIC_LOG(WARNING) << "last_writing_stream_id: " << id; | 
 |       } | 
 |       connection_->CloseConnection(QUIC_INTERNAL_ERROR, | 
 |                                    "WriteBlockedStream is missing", | 
 |                                    ConnectionCloseBehavior::SILENT_CLOSE); | 
 |       return; | 
 |     } | 
 |     if (!CanWriteStreamData()) { | 
 |       return; | 
 |     } | 
 |     currently_writing_stream_id_ = write_blocked_streams_->PopFront(); | 
 |     last_writing_stream_ids.push_back(currently_writing_stream_id_); | 
 |     QUIC_DVLOG(1) << ENDPOINT << "Removing stream " | 
 |                   << currently_writing_stream_id_ << " from write-blocked list"; | 
 |     QuicStream* stream = GetOrCreateStream(currently_writing_stream_id_); | 
 |     if (stream != nullptr && !stream->IsFlowControlBlocked()) { | 
 |       // 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) << ENDPOINT << "stream " << stream->id() | 
 |                     << " bytes_written " << previous_bytes_written << " fin " | 
 |                     << previous_fin_sent; | 
 |       stream->OnCanWrite(); | 
 |       QUICHE_DCHECK(CheckStreamWriteBlocked(stream)); | 
 |       QUICHE_DCHECK(CheckStreamNotBusyLooping(stream, previous_bytes_written, | 
 |                                               previous_fin_sent)); | 
 |     } | 
 |     currently_writing_stream_id_ = 0; | 
 |   } | 
 | } | 
 |  | 
 | 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. | 
 |   if (QuicVersionUsesCryptoFrames(transport_version())) { | 
 |     if (HasPendingHandshake()) { | 
 |       return true; | 
 |     } | 
 |     if (!IsEncryptionEstablished()) { | 
 |       return false; | 
 |     } | 
 |   } | 
 |   if (control_frame_manager_.WillingToWrite() || | 
 |       !streams_with_pending_retransmission_.empty()) { | 
 |     return true; | 
 |   } | 
 |   if (flow_controller_.IsBlocked()) { | 
 |     if (VersionUsesHttp3(transport_version())) { | 
 |       return false; | 
 |     } | 
 |     // Crypto and headers streams are not blocked by connection level flow | 
 |     // control. | 
 |     return write_blocked_streams_->HasWriteBlockedSpecialStream(); | 
 |   } | 
 |   return write_blocked_streams_->HasWriteBlockedSpecialStream() || | 
 |          write_blocked_streams_->HasWriteBlockedDataStreams(); | 
 | } | 
 |  | 
 | std::string QuicSession::GetStreamsInfoForLogging() const { | 
 |   std::string info = absl::StrCat( | 
 |       "num_active_streams: ", GetNumActiveStreams(), | 
 |       ", num_pending_streams: ", pending_streams_size(), | 
 |       ", num_outgoing_draining_streams: ", num_outgoing_draining_streams(), | 
 |       " "); | 
 |   // Log info for up to 5 streams. | 
 |   size_t i = 5; | 
 |   for (const auto& it : stream_map_) { | 
 |     if (it.second->is_static()) { | 
 |       continue; | 
 |     } | 
 |     // Calculate the stream creation delay. | 
 |     const QuicTime::Delta delay = | 
 |         connection_->clock()->ApproximateNow() - it.second->creation_time(); | 
 |     absl::StrAppend( | 
 |         &info, "{", it.second->id(), ":", delay.ToDebuggingValue(), ";", | 
 |         it.second->stream_bytes_written(), ",", it.second->fin_sent(), ",", | 
 |         it.second->HasBufferedData(), ",", it.second->fin_buffered(), ";", | 
 |         it.second->stream_bytes_read(), ",", it.second->fin_received(), "}"); | 
 |     --i; | 
 |     if (i == 0) { | 
 |       break; | 
 |     } | 
 |   } | 
 |   return info; | 
 | } | 
 |  | 
 | bool QuicSession::HasPendingHandshake() const { | 
 |   if (QuicVersionUsesCryptoFrames(transport_version())) { | 
 |     return GetCryptoStream()->HasPendingCryptoRetransmission() || | 
 |            GetCryptoStream()->HasBufferedCryptoFrames(); | 
 |   } | 
 |   return streams_with_pending_retransmission_.contains( | 
 |              QuicUtils::GetCryptoStreamId(transport_version())) || | 
 |          write_blocked_streams_->IsStreamBlocked( | 
 |              QuicUtils::GetCryptoStreamId(transport_version())); | 
 | } | 
 |  | 
 | void QuicSession::ProcessUdpPacket(const QuicSocketAddress& self_address, | 
 |                                    const QuicSocketAddress& peer_address, | 
 |                                    const QuicReceivedPacket& packet) { | 
 |   QuicConnectionContextSwitcher cs(connection_->context()); | 
 |   connection_->ProcessUdpPacket(self_address, peer_address, packet); | 
 | } | 
 |  | 
 | std::string QuicSession::on_closed_frame_string() const { | 
 |   std::stringstream ss; | 
 |   ss << on_closed_frame_; | 
 |   if (connection_close_source_.has_value()) { | 
 |     ss << " " << ConnectionCloseSourceToString(*connection_close_source_); | 
 |   } | 
 |   return ss.str(); | 
 | } | 
 |  | 
 | QuicConsumedData QuicSession::WritevData(QuicStreamId id, size_t write_length, | 
 |                                          QuicStreamOffset offset, | 
 |                                          StreamSendingState state, | 
 |                                          TransmissionType type, | 
 |                                          EncryptionLevel level) { | 
 |   QUIC_BUG_IF(session writevdata when disconnected, !connection()->connected()) | 
 |       << ENDPOINT << "Try to write stream data when connection is closed: " | 
 |       << on_closed_frame_string(); | 
 |   if (!IsEncryptionEstablished() && | 
 |       !QuicUtils::IsCryptoStreamId(transport_version(), id)) { | 
 |     // Do not let streams write without encryption. The calling stream will end | 
 |     // up write blocked until OnCanWrite is next called. | 
 |     if (was_zero_rtt_rejected_ && !OneRttKeysAvailable()) { | 
 |       QUICHE_DCHECK(version().UsesTls() && | 
 |                     perspective() == Perspective::IS_CLIENT); | 
 |       QUIC_DLOG(INFO) << ENDPOINT | 
 |                       << "Suppress the write while 0-RTT gets rejected and " | 
 |                          "1-RTT keys are not available. Version: " | 
 |                       << ParsedQuicVersionToString(version()); | 
 |     } else if (version().UsesTls() || perspective() == Perspective::IS_SERVER) { | 
 |       QUIC_BUG(quic_bug_10866_2) | 
 |           << ENDPOINT << "Try to send data of stream " << id | 
 |           << " before encryption is established. Version: " | 
 |           << ParsedQuicVersionToString(version()); | 
 |     } else { | 
 |       // In QUIC crypto, this could happen when the client sends full CHLO and | 
 |       // 0-RTT request, then receives an inchoate REJ and sends an inchoate | 
 |       // CHLO. The client then gets the ACK of the inchoate CHLO or the client | 
 |       // gets the full REJ and needs to verify the proof (before it sends the | 
 |       // full CHLO), such that there is no outstanding crypto data. | 
 |       // Retransmission alarm fires in TLP mode which tries to retransmit the | 
 |       // 0-RTT request (without encryption). | 
 |       QUIC_DLOG(INFO) << ENDPOINT << "Try to send data of stream " << id | 
 |                       << " before encryption is established."; | 
 |     } | 
 |     return QuicConsumedData(0, false); | 
 |   } | 
 |  | 
 |   SetTransmissionType(type); | 
 |   QuicConnection::ScopedEncryptionLevelContext context(connection(), level); | 
 |  | 
 |   QuicConsumedData data = | 
 |       connection_->SendStreamData(id, write_length, offset, state); | 
 |   if (type == NOT_RETRANSMISSION) { | 
 |     // This is new stream data. | 
 |     write_blocked_streams_->UpdateBytesForStream(id, data.bytes_consumed); | 
 |   } | 
 |  | 
 |   return data; | 
 | } | 
 |  | 
 | size_t QuicSession::SendCryptoData(EncryptionLevel level, size_t write_length, | 
 |                                    QuicStreamOffset offset, | 
 |                                    TransmissionType type) { | 
 |   QUICHE_DCHECK(QuicVersionUsesCryptoFrames(transport_version())); | 
 |   if (!connection()->framer().HasEncrypterOfEncryptionLevel(level)) { | 
 |     const std::string error_details = absl::StrCat( | 
 |         "Try to send crypto data with missing keys of encryption level: ", | 
 |         EncryptionLevelToString(level)); | 
 |     QUIC_BUG(quic_bug_10866_3) << ENDPOINT << error_details; | 
 |     connection()->CloseConnection( | 
 |         QUIC_MISSING_WRITE_KEYS, error_details, | 
 |         ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     return 0; | 
 |   } | 
 |   SetTransmissionType(type); | 
 |   QuicConnection::ScopedEncryptionLevelContext context(connection(), level); | 
 |   const auto bytes_consumed = | 
 |       connection_->SendCryptoData(level, write_length, offset); | 
 |   return bytes_consumed; | 
 | } | 
 |  | 
 | void QuicSession::OnControlFrameManagerError(QuicErrorCode error_code, | 
 |                                              std::string error_details) { | 
 |   connection_->CloseConnection( | 
 |       error_code, error_details, | 
 |       ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 | } | 
 |  | 
 | bool QuicSession::WriteControlFrame(const QuicFrame& frame, | 
 |                                     TransmissionType type) { | 
 |   QUIC_BUG_IF(quic_bug_12435_11, !connection()->connected()) | 
 |       << ENDPOINT | 
 |       << absl::StrCat("Try to write control frame: ", QuicFrameToString(frame), | 
 |                       " when connection is closed: ") | 
 |       << on_closed_frame_string(); | 
 |   if (!IsEncryptionEstablished()) { | 
 |     // Suppress the write before encryption gets established. | 
 |     return false; | 
 |   } | 
 |   SetTransmissionType(type); | 
 |   QuicConnection::ScopedEncryptionLevelContext context( | 
 |       connection(), GetEncryptionLevelToSendApplicationData()); | 
 |   return connection_->SendControlFrame(frame); | 
 | } | 
 |  | 
 | void QuicSession::ResetStream(QuicStreamId id, QuicRstStreamErrorCode error) { | 
 |   QuicStream* stream = GetStream(id); | 
 |   if (stream != nullptr && stream->is_static()) { | 
 |     connection()->CloseConnection( | 
 |         QUIC_INVALID_STREAM_ID, "Try to reset a static stream", | 
 |         ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     return; | 
 |   } | 
 |  | 
 |   if (stream != nullptr) { | 
 |     stream->Reset(error); | 
 |     return; | 
 |   } | 
 |  | 
 |   QuicConnection::ScopedPacketFlusher flusher(connection()); | 
 |   MaybeSendStopSendingFrame(id, QuicResetStreamError::FromInternal(error)); | 
 |   MaybeSendRstStreamFrame(id, QuicResetStreamError::FromInternal(error), 0); | 
 | } | 
 |  | 
 | void QuicSession::MaybeSendRstStreamFrame(QuicStreamId id, | 
 |                                           QuicResetStreamError error, | 
 |                                           QuicStreamOffset bytes_written) { | 
 |   if (!connection()->connected()) { | 
 |     return; | 
 |   } | 
 |   if (!VersionHasIetfQuicFrames(transport_version()) || | 
 |       QuicUtils::GetStreamType(id, perspective(), IsIncomingStream(id), | 
 |                                version()) != READ_UNIDIRECTIONAL) { | 
 |     control_frame_manager_.WriteOrBufferRstStream(id, error, bytes_written); | 
 |   } | 
 |  | 
 |   connection_->OnStreamReset(id, error.internal_code()); | 
 | } | 
 |  | 
 | void QuicSession::MaybeSendResetStreamAtFrame(QuicStreamId id, | 
 |                                               QuicResetStreamError error, | 
 |                                               QuicStreamOffset bytes_written, | 
 |                                               QuicStreamOffset reliable_size) { | 
 |   QUICHE_DCHECK(connection()->reliable_stream_reset_enabled()); | 
 |   if (!connection()->connected()) { | 
 |     return; | 
 |   } | 
 |   control_frame_manager_.WriteOrBufferResetStreamAt(id, error, bytes_written, | 
 |                                                     reliable_size); | 
 | } | 
 |  | 
 | void QuicSession::MaybeSendStopSendingFrame(QuicStreamId id, | 
 |                                             QuicResetStreamError error) { | 
 |   if (!connection()->connected()) { | 
 |     return; | 
 |   } | 
 |   if (VersionHasIetfQuicFrames(transport_version()) && | 
 |       QuicUtils::GetStreamType(id, perspective(), IsIncomingStream(id), | 
 |                                version()) != WRITE_UNIDIRECTIONAL) { | 
 |     control_frame_manager_.WriteOrBufferStopSending(error, id); | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::SendGoAway(QuicErrorCode error_code, | 
 |                              const std::string& reason) { | 
 |   // GOAWAY frame is not supported in IETF QUIC. | 
 |   QUICHE_DCHECK(!VersionHasIetfQuicFrames(transport_version())); | 
 |   if (!IsEncryptionEstablished()) { | 
 |     QUIC_CODE_COUNT(quic_goaway_before_encryption_established); | 
 |     connection_->CloseConnection( | 
 |         error_code, reason, | 
 |         ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     return; | 
 |   } | 
 |   if (transport_goaway_sent_) { | 
 |     return; | 
 |   } | 
 |   transport_goaway_sent_ = true; | 
 |  | 
 |   QUICHE_DCHECK_EQ(perspective(), Perspective::IS_SERVER); | 
 |   control_frame_manager_.WriteOrBufferGoAway( | 
 |       error_code, | 
 |       QuicUtils::GetMaxClientInitiatedBidirectionalStreamId( | 
 |           transport_version()), | 
 |       reason); | 
 | } | 
 |  | 
 | void QuicSession::SendBlocked(QuicStreamId id, QuicStreamOffset byte_offset) { | 
 |   control_frame_manager_.WriteOrBufferBlocked(id, byte_offset); | 
 | } | 
 |  | 
 | void QuicSession::SendWindowUpdate(QuicStreamId id, | 
 |                                    QuicStreamOffset byte_offset) { | 
 |   control_frame_manager_.WriteOrBufferWindowUpdate(id, byte_offset); | 
 | } | 
 |  | 
 | void QuicSession::OnStreamError(QuicErrorCode error_code, | 
 |                                 std::string error_details) { | 
 |   connection_->CloseConnection( | 
 |       error_code, error_details, | 
 |       ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 | } | 
 |  | 
 | void QuicSession::OnStreamError(QuicErrorCode error_code, | 
 |                                 QuicIetfTransportErrorCodes ietf_error, | 
 |                                 std::string error_details) { | 
 |   connection_->CloseConnection( | 
 |       error_code, ietf_error, error_details, | 
 |       ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 | } | 
 |  | 
 | bool QuicSession::CanSendMaxStreams() { | 
 |   return control_frame_manager_.NumBufferedMaxStreams() < 2; | 
 | } | 
 |  | 
 | void QuicSession::SendMaxStreams(QuicStreamCount stream_count, | 
 |                                  bool unidirectional) { | 
 |   if (!is_configured_) { | 
 |     QUIC_BUG(quic_bug_10866_5) | 
 |         << "Try to send max streams before config negotiated."; | 
 |     return; | 
 |   } | 
 |   control_frame_manager_.WriteOrBufferMaxStreams(stream_count, unidirectional); | 
 | } | 
 |  | 
 | void QuicSession::InsertLocallyClosedStreamsHighestOffset( | 
 |     const QuicStreamId id, QuicStreamOffset offset) { | 
 |   locally_closed_streams_highest_offset_[id] = offset; | 
 | } | 
 |  | 
 | void QuicSession::OnStreamClosed(QuicStreamId stream_id) { | 
 |   QUIC_DVLOG(1) << ENDPOINT << "Closing stream: " << stream_id; | 
 |   StreamMap::iterator it = stream_map_.find(stream_id); | 
 |   if (it == stream_map_.end()) { | 
 |     QUIC_BUG(quic_bug_10866_6) | 
 |         << ENDPOINT << "Stream is already closed: " << stream_id; | 
 |     return; | 
 |   } | 
 |   QuicStream* stream = it->second.get(); | 
 |   StreamType type = stream->type(); | 
 |  | 
 |   const bool stream_waiting_for_acks = stream->IsWaitingForAcks(); | 
 |   if (stream_waiting_for_acks) { | 
 |     // The stream needs to be kept alive because it's waiting for acks. | 
 |     ++num_zombie_streams_; | 
 |   } else { | 
 |     PrepareStreamForDestruction(it); | 
 |     // 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()); | 
 |     } | 
 |     connection_->QuicBugIfHasPendingFrames(stream_id); | 
 |   } | 
 |  | 
 |   if (!stream->HasReceivedFinalOffset()) { | 
 |     // 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. | 
 |     // If this is an outgoing stream, it is technically open from peer's | 
 |     // perspective. Do not inform stream Id manager yet. | 
 |     QUICHE_DCHECK(!stream->was_draining()); | 
 |     InsertLocallyClosedStreamsHighestOffset( | 
 |         stream_id, stream->highest_received_byte_offset()); | 
 |     return; | 
 |   } | 
 |  | 
 |   const bool stream_was_draining = stream->was_draining(); | 
 |   QUIC_DVLOG_IF(1, stream_was_draining) | 
 |       << ENDPOINT << "Stream " << stream_id << " was draining"; | 
 |   if (stream_was_draining) { | 
 |     QUIC_BUG_IF(quic_bug_12435_4, num_draining_streams_ == 0); | 
 |     --num_draining_streams_; | 
 |     if (!IsIncomingStream(stream_id)) { | 
 |       QUIC_BUG_IF(quic_bug_12435_5, num_outgoing_draining_streams_ == 0); | 
 |       --num_outgoing_draining_streams_; | 
 |     } | 
 |     // Stream Id manager has been informed with draining streams. | 
 |     return; | 
 |   } | 
 |   if (!VersionHasIetfQuicFrames(transport_version())) { | 
 |     stream_id_manager_.OnStreamClosed( | 
 |         /*is_incoming=*/IsIncomingStream(stream_id)); | 
 |   } | 
 |   if (!connection_->connected()) { | 
 |     return; | 
 |   } | 
 |   if (IsIncomingStream(stream_id)) { | 
 |     // Stream Id manager is only interested in peer initiated stream IDs. | 
 |     if (VersionHasIetfQuicFrames(transport_version())) { | 
 |       ietf_streamid_manager_.OnStreamClosed(stream_id); | 
 |     } | 
 |     return; | 
 |   } | 
 |   if (!VersionHasIetfQuicFrames(transport_version())) { | 
 |     OnCanCreateNewOutgoingStream(type != BIDIRECTIONAL); | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::ClosePendingStream(QuicStreamId stream_id) { | 
 |   QUIC_DVLOG(1) << ENDPOINT << "Closing stream " << stream_id; | 
 |   QUICHE_DCHECK(VersionHasIetfQuicFrames(transport_version())); | 
 |   pending_stream_map_.erase(stream_id); | 
 |   if (connection_->connected()) { | 
 |     ietf_streamid_manager_.OnStreamClosed(stream_id); | 
 |   } | 
 | } | 
 |  | 
 | bool QuicSession::ShouldProcessFrameByPendingStream(QuicFrameType type, | 
 |                                                     QuicStreamId id) const { | 
 |   return stream_map_.find(id) == stream_map_.end() && | 
 |          ((version().HasIetfQuicFrames() && ExceedsPerLoopStreamLimit()) || | 
 |           UsesPendingStreamForFrame(type, 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 (!VersionHasIetfQuicFrames(transport_version())) { | 
 |     stream_id_manager_.OnStreamClosed( | 
 |         /*is_incoming=*/IsIncomingStream(stream_id)); | 
 |   } | 
 |   if (IsIncomingStream(stream_id)) { | 
 |     if (VersionHasIetfQuicFrames(transport_version())) { | 
 |       ietf_streamid_manager_.OnStreamClosed(stream_id); | 
 |     } | 
 |   } else if (!VersionHasIetfQuicFrames(transport_version())) { | 
 |     OnCanCreateNewOutgoingStream(false); | 
 |   } | 
 | } | 
 |  | 
 | bool QuicSession::IsEncryptionEstablished() const { | 
 |   if (GetCryptoStream() == nullptr) { | 
 |     return false; | 
 |   } | 
 |   return GetCryptoStream()->encryption_established(); | 
 | } | 
 |  | 
 | bool QuicSession::OneRttKeysAvailable() const { | 
 |   if (GetCryptoStream() == nullptr) { | 
 |     return false; | 
 |   } | 
 |   return GetCryptoStream()->one_rtt_keys_available(); | 
 | } | 
 |  | 
 | void QuicSession::OnConfigNegotiated() { | 
 |   // In versions with TLS, the configs will be set twice if 0-RTT is available. | 
 |   // In the second config setting, 1-RTT keys are guaranteed to be available. | 
 |   if (version().UsesTls() && is_configured_ && | 
 |       connection_->encryption_level() != ENCRYPTION_FORWARD_SECURE) { | 
 |     QUIC_BUG(quic_bug_12435_6) | 
 |         << ENDPOINT | 
 |         << "1-RTT keys missing when config is negotiated for the second time."; | 
 |     connection_->CloseConnection( | 
 |         QUIC_INTERNAL_ERROR, | 
 |         "1-RTT keys missing when config is negotiated for the second time.", | 
 |         ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     return; | 
 |   } | 
 |  | 
 |   QUIC_DVLOG(1) << ENDPOINT << "OnConfigNegotiated"; | 
 |   connection_->SetFromConfig(config_); | 
 |  | 
 |   if (VersionHasIetfQuicFrames(transport_version())) { | 
 |     uint32_t max_streams = 0; | 
 |     if (config_.HasReceivedMaxBidirectionalStreams()) { | 
 |       max_streams = config_.ReceivedMaxBidirectionalStreams(); | 
 |     } | 
 |     if (was_zero_rtt_rejected_ && | 
 |         max_streams < | 
 |             ietf_streamid_manager_.outgoing_bidirectional_stream_count()) { | 
 |       connection_->CloseConnection( | 
 |           QUIC_ZERO_RTT_UNRETRANSMITTABLE, | 
 |           absl::StrCat( | 
 |               "Server rejected 0-RTT, aborting because new bidirectional " | 
 |               "initial stream limit ", | 
 |               max_streams, " is less than current open streams: ", | 
 |               ietf_streamid_manager_.outgoing_bidirectional_stream_count()), | 
 |           ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |       return; | 
 |     } | 
 |     QUIC_DVLOG(1) << ENDPOINT | 
 |                   << "Setting Bidirectional outgoing_max_streams_ to " | 
 |                   << max_streams; | 
 |     if (perspective_ == Perspective::IS_CLIENT && | 
 |         max_streams < | 
 |             ietf_streamid_manager_.max_outgoing_bidirectional_streams()) { | 
 |       connection_->CloseConnection( | 
 |           was_zero_rtt_rejected_ ? QUIC_ZERO_RTT_REJECTION_LIMIT_REDUCED | 
 |                                  : QUIC_ZERO_RTT_RESUMPTION_LIMIT_REDUCED, | 
 |           absl::StrCat( | 
 |               was_zero_rtt_rejected_ | 
 |                   ? "Server rejected 0-RTT, aborting because " | 
 |                   : "", | 
 |               "new bidirectional limit ", max_streams, | 
 |               " decreases the current limit: ", | 
 |               ietf_streamid_manager_.max_outgoing_bidirectional_streams()), | 
 |           ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |       return; | 
 |     } | 
 |     if (ietf_streamid_manager_.MaybeAllowNewOutgoingBidirectionalStreams( | 
 |             max_streams)) { | 
 |       OnCanCreateNewOutgoingStream(/*unidirectional = */ false); | 
 |     } | 
 |  | 
 |     max_streams = 0; | 
 |     if (config_.HasReceivedMaxUnidirectionalStreams()) { | 
 |       max_streams = config_.ReceivedMaxUnidirectionalStreams(); | 
 |     } | 
 |  | 
 |     if (was_zero_rtt_rejected_ && | 
 |         max_streams < | 
 |             ietf_streamid_manager_.outgoing_unidirectional_stream_count()) { | 
 |       connection_->CloseConnection( | 
 |           QUIC_ZERO_RTT_UNRETRANSMITTABLE, | 
 |           absl::StrCat( | 
 |               "Server rejected 0-RTT, aborting because new unidirectional " | 
 |               "initial stream limit ", | 
 |               max_streams, " is less than current open streams: ", | 
 |               ietf_streamid_manager_.outgoing_unidirectional_stream_count()), | 
 |           ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |       return; | 
 |     } | 
 |  | 
 |     if (max_streams < | 
 |         ietf_streamid_manager_.max_outgoing_unidirectional_streams()) { | 
 |       connection_->CloseConnection( | 
 |           was_zero_rtt_rejected_ ? QUIC_ZERO_RTT_REJECTION_LIMIT_REDUCED | 
 |                                  : QUIC_ZERO_RTT_RESUMPTION_LIMIT_REDUCED, | 
 |           absl::StrCat( | 
 |               was_zero_rtt_rejected_ | 
 |                   ? "Server rejected 0-RTT, aborting because " | 
 |                   : "", | 
 |               "new unidirectional limit ", max_streams, | 
 |               " decreases the current limit: ", | 
 |               ietf_streamid_manager_.max_outgoing_unidirectional_streams()), | 
 |           ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |       return; | 
 |     } | 
 |     QUIC_DVLOG(1) << ENDPOINT | 
 |                   << "Setting Unidirectional outgoing_max_streams_ to " | 
 |                   << max_streams; | 
 |     if (ietf_streamid_manager_.MaybeAllowNewOutgoingUnidirectionalStreams( | 
 |             max_streams)) { | 
 |       OnCanCreateNewOutgoingStream(/*unidirectional = */ true); | 
 |     } | 
 |   } else { | 
 |     uint32_t max_streams = 0; | 
 |     if (config_.HasReceivedMaxBidirectionalStreams()) { | 
 |       max_streams = config_.ReceivedMaxBidirectionalStreams(); | 
 |     } | 
 |     QUIC_DVLOG(1) << ENDPOINT << "Setting max_open_outgoing_streams_ to " | 
 |                   << max_streams; | 
 |     if (was_zero_rtt_rejected_ && | 
 |         max_streams < stream_id_manager_.num_open_outgoing_streams()) { | 
 |       connection_->CloseConnection( | 
 |           QUIC_INTERNAL_ERROR, | 
 |           absl::StrCat( | 
 |               "Server rejected 0-RTT, aborting because new stream limit ", | 
 |               max_streams, " is less than current open streams: ", | 
 |               stream_id_manager_.num_open_outgoing_streams()), | 
 |           ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |       return; | 
 |     } | 
 |     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(transport_version())) { | 
 |     ietf_streamid_manager_.SetMaxOpenIncomingBidirectionalStreams( | 
 |         config_.GetMaxBidirectionalStreamsToSend()); | 
 |     ietf_streamid_manager_.SetMaxOpenIncomingUnidirectionalStreams( | 
 |         config_.GetMaxUnidirectionalStreamsToSend()); | 
 |   } 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_.GetMaxBidirectionalStreamsToSend(); | 
 |     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 (connection_->version().handshake_protocol == PROTOCOL_TLS1_3) { | 
 |     // When using IETF-style TLS transport parameters, inform existing streams | 
 |     // of new flow-control limits. | 
 |     if (config_.HasReceivedInitialMaxStreamDataBytesOutgoingBidirectional()) { | 
 |       OnNewStreamOutgoingBidirectionalFlowControlWindow( | 
 |           config_.ReceivedInitialMaxStreamDataBytesOutgoingBidirectional()); | 
 |     } | 
 |     if (config_.HasReceivedInitialMaxStreamDataBytesIncomingBidirectional()) { | 
 |       OnNewStreamIncomingBidirectionalFlowControlWindow( | 
 |           config_.ReceivedInitialMaxStreamDataBytesIncomingBidirectional()); | 
 |     } | 
 |     if (config_.HasReceivedInitialMaxStreamDataBytesUnidirectional()) { | 
 |       OnNewStreamUnidirectionalFlowControlWindow( | 
 |           config_.ReceivedInitialMaxStreamDataBytesUnidirectional()); | 
 |     } | 
 |   } else {  // The version uses Google QUIC Crypto. | 
 |     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()); | 
 |   } | 
 |  | 
 |   if (perspective_ == Perspective::IS_SERVER && version().HasIetfQuicFrames() && | 
 |       connection_->effective_peer_address().IsInitialized()) { | 
 |     if (config_.SupportsServerPreferredAddress(perspective_)) { | 
 |       quiche::IpAddressFamily address_family = | 
 |           connection_->effective_peer_address() | 
 |               .Normalized() | 
 |               .host() | 
 |               .address_family(); | 
 |       std::optional<QuicSocketAddress> expected_preferred_address = | 
 |           config_.GetMappedAlternativeServerAddress(address_family); | 
 |       if (expected_preferred_address.has_value()) { | 
 |         // Set connection ID and token if SPAD has received and a preferred | 
 |         // address of the same address family is configured. | 
 |         std::optional<QuicNewConnectionIdFrame> frame = | 
 |             connection_->MaybeIssueNewConnectionIdForPreferredAddress(); | 
 |         if (frame.has_value()) { | 
 |           config_.SetPreferredAddressConnectionIdAndTokenToSend( | 
 |               frame->connection_id, frame->stateless_reset_token); | 
 |         } | 
 |         connection_->set_expected_server_preferred_address( | 
 |             *expected_preferred_address); | 
 |       } | 
 |       // Clear the alternative address of the other address family in the | 
 |       // config. | 
 |       config_.ClearAlternateServerAddressToSend( | 
 |           address_family == quiche::IpAddressFamily::IP_V4 | 
 |               ? quiche::IpAddressFamily::IP_V6 | 
 |               : quiche::IpAddressFamily::IP_V4); | 
 |     } else { | 
 |       // Clear alternative IPv(4|6) addresses in config if the server hasn't | 
 |       // received 'SPAD' connection option. | 
 |       config_.ClearAlternateServerAddressToSend(quiche::IpAddressFamily::IP_V4); | 
 |       config_.ClearAlternateServerAddressToSend(quiche::IpAddressFamily::IP_V6); | 
 |     } | 
 |   } | 
 |  | 
 |   is_configured_ = true; | 
 |   connection()->OnConfigNegotiated(); | 
 |  | 
 |   // Ask flow controllers to try again since the config could have unblocked us. | 
 |   // Or if this session is configured on TLS enabled QUIC versions, | 
 |   // attempt to retransmit 0-RTT data if there's any. | 
 |   // TODO(fayang): consider removing this OnCanWrite call. | 
 |   if (!connection_->framer().is_processing_packet() && | 
 |       (connection_->version().AllowsLowFlowControlLimits() || | 
 |        version().UsesTls())) { | 
 |     QUIC_CODE_COUNT(quic_session_on_can_write_on_config_negotiated); | 
 |     OnCanWrite(); | 
 |   } | 
 | } | 
 |  | 
 | std::optional<std::string> QuicSession::OnAlpsData(const uint8_t* /*alps_data*/, | 
 |                                                    size_t /*alps_length*/) { | 
 |   return std::nullopt; | 
 | } | 
 |  | 
 | 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->UpdateReceiveWindowSize(stream_window); | 
 |   } | 
 |   if (!QuicVersionUsesCryptoFrames(transport_version())) { | 
 |     GetMutableCryptoStream()->UpdateReceiveWindowSize(stream_window); | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::HandleFrameOnNonexistentOutgoingStream( | 
 |     QuicStreamId stream_id) { | 
 |   QUICHE_DCHECK(!IsClosedStream(stream_id)); | 
 |   // Received a frame for a locally-created stream that is not currently | 
 |   // active. This is an error. | 
 |   if (VersionHasIetfQuicFrames(transport_version())) { | 
 |     connection()->CloseConnection( | 
 |         QUIC_HTTP_STREAM_WRONG_DIRECTION, "Data for nonexistent stream", | 
 |         ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     return; | 
 |   } | 
 |   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) { | 
 |   QUICHE_DCHECK(version().UsesQuicCrypto()); | 
 |   QUIC_DVLOG(1) << ENDPOINT << "OnNewStreamFlowControlWindow " << new_window; | 
 |   if (new_window < kMinimumFlowControlSendWindow) { | 
 |     QUIC_LOG_FIRST_N(ERROR, 1) | 
 |         << "Peer sent us an invalid stream flow control send window: " | 
 |         << new_window << ", below minimum: " << kMinimumFlowControlSendWindow; | 
 |     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_) { | 
 |     QUIC_DVLOG(1) << ENDPOINT << "Informing stream " << kv.first | 
 |                   << " of new stream flow control window " << new_window; | 
 |     if (!kv.second->MaybeConfigSendWindowOffset( | 
 |             new_window, /* was_zero_rtt_rejected = */ false)) { | 
 |       return; | 
 |     } | 
 |   } | 
 |   if (!QuicVersionUsesCryptoFrames(transport_version())) { | 
 |     QUIC_DVLOG(1) | 
 |         << ENDPOINT | 
 |         << "Informing crypto stream of new stream flow control window " | 
 |         << new_window; | 
 |     GetMutableCryptoStream()->MaybeConfigSendWindowOffset( | 
 |         new_window, /* was_zero_rtt_rejected = */ false); | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::OnNewStreamUnidirectionalFlowControlWindow( | 
 |     QuicStreamOffset new_window) { | 
 |   QUICHE_DCHECK_EQ(connection_->version().handshake_protocol, PROTOCOL_TLS1_3); | 
 |   QUIC_DVLOG(1) << ENDPOINT << "OnNewStreamUnidirectionalFlowControlWindow " | 
 |                 << new_window; | 
 |   // Inform all existing outgoing unidirectional streams about the new window. | 
 |   for (auto const& kv : stream_map_) { | 
 |     const QuicStreamId id = kv.first; | 
 |     if (!version().HasIetfQuicFrames()) { | 
 |       if (kv.second->type() == BIDIRECTIONAL) { | 
 |         continue; | 
 |       } | 
 |     } else { | 
 |       if (QuicUtils::IsBidirectionalStreamId(id, version())) { | 
 |         continue; | 
 |       } | 
 |     } | 
 |     if (!QuicUtils::IsOutgoingStreamId(connection_->version(), id, | 
 |                                        perspective())) { | 
 |       continue; | 
 |     } | 
 |     QUIC_DVLOG(1) << ENDPOINT << "Informing unidirectional stream " << id | 
 |                   << " of new stream flow control window " << new_window; | 
 |     if (!kv.second->MaybeConfigSendWindowOffset(new_window, | 
 |                                                 was_zero_rtt_rejected_)) { | 
 |       return; | 
 |     } | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::OnNewStreamOutgoingBidirectionalFlowControlWindow( | 
 |     QuicStreamOffset new_window) { | 
 |   QUICHE_DCHECK_EQ(connection_->version().handshake_protocol, PROTOCOL_TLS1_3); | 
 |   QUIC_DVLOG(1) << ENDPOINT | 
 |                 << "OnNewStreamOutgoingBidirectionalFlowControlWindow " | 
 |                 << new_window; | 
 |   // Inform all existing outgoing bidirectional streams about the new window. | 
 |   for (auto const& kv : stream_map_) { | 
 |     const QuicStreamId id = kv.first; | 
 |     if (!version().HasIetfQuicFrames()) { | 
 |       if (kv.second->type() != BIDIRECTIONAL) { | 
 |         continue; | 
 |       } | 
 |     } else { | 
 |       if (!QuicUtils::IsBidirectionalStreamId(id, version())) { | 
 |         continue; | 
 |       } | 
 |     } | 
 |     if (!QuicUtils::IsOutgoingStreamId(connection_->version(), id, | 
 |                                        perspective())) { | 
 |       continue; | 
 |     } | 
 |     QUIC_DVLOG(1) << ENDPOINT << "Informing outgoing bidirectional stream " | 
 |                   << id << " of new stream flow control window " << new_window; | 
 |     if (!kv.second->MaybeConfigSendWindowOffset(new_window, | 
 |                                                 was_zero_rtt_rejected_)) { | 
 |       return; | 
 |     } | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::OnNewStreamIncomingBidirectionalFlowControlWindow( | 
 |     QuicStreamOffset new_window) { | 
 |   QUICHE_DCHECK_EQ(connection_->version().handshake_protocol, PROTOCOL_TLS1_3); | 
 |   QUIC_DVLOG(1) << ENDPOINT | 
 |                 << "OnNewStreamIncomingBidirectionalFlowControlWindow " | 
 |                 << new_window; | 
 |   // Inform all existing incoming bidirectional streams about the new window. | 
 |   for (auto const& kv : stream_map_) { | 
 |     const QuicStreamId id = kv.first; | 
 |     if (!version().HasIetfQuicFrames()) { | 
 |       if (kv.second->type() != BIDIRECTIONAL) { | 
 |         continue; | 
 |       } | 
 |     } else { | 
 |       if (!QuicUtils::IsBidirectionalStreamId(id, version())) { | 
 |         continue; | 
 |       } | 
 |     } | 
 |     if (QuicUtils::IsOutgoingStreamId(connection_->version(), id, | 
 |                                       perspective())) { | 
 |       continue; | 
 |     } | 
 |     QUIC_DVLOG(1) << ENDPOINT << "Informing incoming bidirectional stream " | 
 |                   << id << " of new stream flow control window " << new_window; | 
 |     if (!kv.second->MaybeConfigSendWindowOffset(new_window, | 
 |                                                 was_zero_rtt_rejected_)) { | 
 |       return; | 
 |     } | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::OnNewSessionFlowControlWindow(QuicStreamOffset new_window) { | 
 |   QUIC_DVLOG(1) << ENDPOINT << "OnNewSessionFlowControlWindow " << new_window; | 
 |  | 
 |   if (was_zero_rtt_rejected_ && new_window < flow_controller_.bytes_sent()) { | 
 |     std::string error_details = absl::StrCat( | 
 |         "Server rejected 0-RTT. Aborting because the client received session " | 
 |         "flow control send window: ", | 
 |         new_window, | 
 |         ", which is below currently used: ", flow_controller_.bytes_sent()); | 
 |     QUIC_LOG(ERROR) << error_details; | 
 |     connection_->CloseConnection( | 
 |         QUIC_ZERO_RTT_UNRETRANSMITTABLE, error_details, | 
 |         ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     return; | 
 |   } | 
 |   if (!connection_->version().AllowsLowFlowControlLimits() && | 
 |       new_window < kMinimumFlowControlSendWindow) { | 
 |     std::string error_details = absl::StrCat( | 
 |         "Peer sent us an invalid session flow control send window: ", | 
 |         new_window, ", below minimum: ", kMinimumFlowControlSendWindow); | 
 |     QUIC_LOG_FIRST_N(ERROR, 1) << error_details; | 
 |     connection_->CloseConnection( | 
 |         QUIC_FLOW_CONTROL_INVALID_WINDOW, error_details, | 
 |         ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     return; | 
 |   } | 
 |   if (perspective_ == Perspective::IS_CLIENT && | 
 |       new_window < flow_controller_.send_window_offset()) { | 
 |     // The client receives a lower limit than remembered, violating | 
 |     // https://tools.ietf.org/html/draft-ietf-quic-transport-27#section-7.3.1 | 
 |     std::string error_details = absl::StrCat( | 
 |         was_zero_rtt_rejected_ ? "Server rejected 0-RTT, aborting because " | 
 |                                : "", | 
 |         "new session max data ", new_window, | 
 |         " decreases current limit: ", flow_controller_.send_window_offset()); | 
 |     QUIC_LOG(ERROR) << error_details; | 
 |     connection_->CloseConnection( | 
 |         was_zero_rtt_rejected_ ? QUIC_ZERO_RTT_REJECTION_LIMIT_REDUCED | 
 |                                : QUIC_ZERO_RTT_RESUMPTION_LIMIT_REDUCED, | 
 |         error_details, ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     return; | 
 |   } | 
 |  | 
 |   flow_controller_.UpdateSendWindowOffset(new_window); | 
 | } | 
 |  | 
 | bool QuicSession::OnNewDecryptionKeyAvailable( | 
 |     EncryptionLevel level, std::unique_ptr<QuicDecrypter> decrypter, | 
 |     bool set_alternative_decrypter, bool latch_once_used) { | 
 |   if (connection_->version().handshake_protocol == PROTOCOL_TLS1_3 && | 
 |       !connection()->framer().HasEncrypterOfEncryptionLevel( | 
 |           QuicUtils::GetEncryptionLevelToSendAckofSpace( | 
 |               QuicUtils::GetPacketNumberSpace(level)))) { | 
 |     // This should never happen because connection should never decrypt a packet | 
 |     // while an ACK for it cannot be encrypted. | 
 |     return false; | 
 |   } | 
 |   if (connection()->version().KnowsWhichDecrypterToUse()) { | 
 |     connection()->InstallDecrypter(level, std::move(decrypter)); | 
 |     return true; | 
 |   } | 
 |   if (set_alternative_decrypter) { | 
 |     connection()->SetAlternativeDecrypter(level, std::move(decrypter), | 
 |                                           latch_once_used); | 
 |     return true; | 
 |   } | 
 |   connection()->SetDecrypter(level, std::move(decrypter)); | 
 |   return true; | 
 | } | 
 |  | 
 | void QuicSession::OnNewEncryptionKeyAvailable( | 
 |     EncryptionLevel level, std::unique_ptr<QuicEncrypter> encrypter) { | 
 |   connection()->SetEncrypter(level, std::move(encrypter)); | 
 |   if (connection_->version().handshake_protocol != PROTOCOL_TLS1_3) { | 
 |     return; | 
 |   } | 
 |  | 
 |   bool reset_encryption_level = false; | 
 |   if (IsEncryptionEstablished() && level == ENCRYPTION_HANDSHAKE) { | 
 |     // ENCRYPTION_HANDSHAKE keys are only used for the handshake. If | 
 |     // ENCRYPTION_ZERO_RTT keys exist, it is possible for a client to send | 
 |     // stream data, which must not be sent at the ENCRYPTION_HANDSHAKE level. | 
 |     // Therefore, we avoid setting the default encryption level to | 
 |     // ENCRYPTION_HANDSHAKE. | 
 |     reset_encryption_level = true; | 
 |   } | 
 |   QUIC_DVLOG(1) << ENDPOINT << "Set default encryption level to " << level; | 
 |   connection()->SetDefaultEncryptionLevel(level); | 
 |   if (reset_encryption_level) { | 
 |     connection()->SetDefaultEncryptionLevel(ENCRYPTION_ZERO_RTT); | 
 |   } | 
 |   QUIC_BUG_IF(quic_bug_12435_7, | 
 |               IsEncryptionEstablished() && | 
 |                   (connection()->encryption_level() == ENCRYPTION_INITIAL || | 
 |                    connection()->encryption_level() == ENCRYPTION_HANDSHAKE)) | 
 |       << "Encryption is established, but the encryption level " << level | 
 |       << " does not support sending stream data"; | 
 | } | 
 |  | 
 | void QuicSession::SetDefaultEncryptionLevel(EncryptionLevel level) { | 
 |   QUICHE_DCHECK_EQ(PROTOCOL_QUIC_CRYPTO, | 
 |                    connection_->version().handshake_protocol); | 
 |   QUIC_DVLOG(1) << ENDPOINT << "Set default encryption level to " << level; | 
 |   connection()->SetDefaultEncryptionLevel(level); | 
 |  | 
 |   switch (level) { | 
 |     case ENCRYPTION_INITIAL: | 
 |       break; | 
 |     case ENCRYPTION_ZERO_RTT: | 
 |       if (perspective() == Perspective::IS_CLIENT) { | 
 |         // Retransmit old 0-RTT data (if any) with the new 0-RTT keys, since | 
 |         // they can't be decrypted by the server. | 
 |         connection_->MarkZeroRttPacketsForRetransmission(0); | 
 |         if (!connection_->framer().is_processing_packet()) { | 
 |           // TODO(fayang): consider removing this OnCanWrite call. | 
 |           // Given any streams blocked by encryption a chance to write. | 
 |           QUIC_CODE_COUNT( | 
 |               quic_session_on_can_write_set_default_encryption_level); | 
 |           OnCanWrite(); | 
 |         } | 
 |       } | 
 |       break; | 
 |     case ENCRYPTION_HANDSHAKE: | 
 |       break; | 
 |     case ENCRYPTION_FORWARD_SECURE: | 
 |       QUIC_BUG_IF(quic_bug_12435_8, !config_.negotiated()) | 
 |           << ENDPOINT << "Handshake confirmed without parameter negotiation."; | 
 |       connection()->mutable_stats().handshake_completion_time = | 
 |           connection()->clock()->ApproximateNow(); | 
 |       break; | 
 |     default: | 
 |       QUIC_BUG(quic_bug_10866_7) << "Unknown encryption level: " << level; | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::OnTlsHandshakeComplete() { | 
 |   QUICHE_DCHECK_EQ(PROTOCOL_TLS1_3, connection_->version().handshake_protocol); | 
 |   QUIC_BUG_IF(quic_bug_12435_9, | 
 |               !GetCryptoStream()->crypto_negotiated_params().cipher_suite) | 
 |       << ENDPOINT << "Handshake completes without cipher suite negotiation."; | 
 |   QUIC_BUG_IF(quic_bug_12435_10, !config_.negotiated()) | 
 |       << ENDPOINT << "Handshake completes without parameter negotiation."; | 
 |   connection()->mutable_stats().handshake_completion_time = | 
 |       connection()->clock()->ApproximateNow(); | 
 |   if (connection()->ShouldFixTimeouts(config_)) { | 
 |     QUIC_RELOADABLE_FLAG_COUNT_N(quic_fix_timeouts, 2, 2); | 
 |     // Handshake complete, set handshake timeout to Infinite. | 
 |     connection()->SetNetworkTimeouts(QuicTime::Delta::Infinite(), | 
 |                                      config_.IdleNetworkTimeout()); | 
 |   } | 
 |   if (connection()->version().UsesTls() && | 
 |       perspective_ == Perspective::IS_SERVER) { | 
 |     // Server sends HANDSHAKE_DONE to signal confirmation of the handshake | 
 |     // to the client. | 
 |     control_frame_manager_.WriteOrBufferHandshakeDone(); | 
 |     if (connection()->version().HasIetfQuicFrames()) { | 
 |       MaybeSendAddressToken(); | 
 |     } | 
 |   } | 
 | } | 
 |  | 
 | bool QuicSession::MaybeSendAddressToken() { | 
 |   QUICHE_DCHECK(perspective_ == Perspective::IS_SERVER && | 
 |                 connection()->version().HasIetfQuicFrames()); | 
 |   std::optional<CachedNetworkParameters> cached_network_params = | 
 |       GenerateCachedNetworkParameters(); | 
 |  | 
 |   std::string address_token = GetCryptoStream()->GetAddressToken( | 
 |       cached_network_params.has_value() ? &*cached_network_params : nullptr); | 
 |   if (address_token.empty()) { | 
 |     return false; | 
 |   } | 
 |   const size_t buf_len = address_token.length() + 1; | 
 |   auto buffer = std::make_unique<char[]>(buf_len); | 
 |   QuicDataWriter writer(buf_len, buffer.get()); | 
 |   // Add |kAddressTokenPrefix| for token sent in NEW_TOKEN frame. | 
 |   writer.WriteUInt8(kAddressTokenPrefix); | 
 |   writer.WriteBytes(address_token.data(), address_token.length()); | 
 |   control_frame_manager_.WriteOrBufferNewToken( | 
 |       absl::string_view(buffer.get(), buf_len)); | 
 |   if (cached_network_params.has_value()) { | 
 |     connection()->OnSendConnectionState(*cached_network_params); | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | void QuicSession::DiscardOldDecryptionKey(EncryptionLevel level) { | 
 |   if (!connection()->version().KnowsWhichDecrypterToUse()) { | 
 |     return; | 
 |   } | 
 |   connection()->RemoveDecrypter(level); | 
 | } | 
 |  | 
 | void QuicSession::DiscardOldEncryptionKey(EncryptionLevel level) { | 
 |   QUIC_DLOG(INFO) << ENDPOINT << "Discarding " << level << " keys"; | 
 |   if (connection()->version().handshake_protocol == PROTOCOL_TLS1_3) { | 
 |     connection()->RemoveEncrypter(level); | 
 |   } | 
 |   switch (level) { | 
 |     case ENCRYPTION_INITIAL: | 
 |       NeuterUnencryptedData(); | 
 |       break; | 
 |     case ENCRYPTION_HANDSHAKE: | 
 |       NeuterHandshakeData(); | 
 |       break; | 
 |     case ENCRYPTION_ZERO_RTT: | 
 |       break; | 
 |     case ENCRYPTION_FORWARD_SECURE: | 
 |       QUIC_BUG(quic_bug_10866_8) | 
 |           << ENDPOINT << "Discarding 1-RTT keys is not allowed"; | 
 |       break; | 
 |     default: | 
 |       QUIC_BUG(quic_bug_10866_9) | 
 |           << ENDPOINT | 
 |           << "Cannot discard keys for unknown encryption level: " << level; | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::NeuterHandshakeData() { | 
 |   GetMutableCryptoStream()->NeuterStreamDataOfEncryptionLevel( | 
 |       ENCRYPTION_HANDSHAKE); | 
 |   connection()->OnHandshakeComplete(); | 
 | } | 
 |  | 
 | void QuicSession::OnZeroRttRejected(int reason) { | 
 |   was_zero_rtt_rejected_ = true; | 
 |   connection_->MarkZeroRttPacketsForRetransmission(reason); | 
 |   if (connection_->encryption_level() == ENCRYPTION_FORWARD_SECURE) { | 
 |     QUIC_BUG(quic_bug_10866_10) | 
 |         << "1-RTT keys already available when 0-RTT is rejected."; | 
 |     connection_->CloseConnection( | 
 |         QUIC_INTERNAL_ERROR, | 
 |         "1-RTT keys already available when 0-RTT is rejected.", | 
 |         ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |   } | 
 | } | 
 |  | 
 | bool QuicSession::FillTransportParameters(TransportParameters* params) { | 
 |   if (version().UsesTls()) { | 
 |     if (perspective() == Perspective::IS_SERVER) { | 
 |       config_.SetOriginalConnectionIdToSend( | 
 |           connection_->GetOriginalDestinationConnectionId()); | 
 |       config_.SetInitialSourceConnectionIdToSend(connection_->connection_id()); | 
 |     } else { | 
 |       config_.SetInitialSourceConnectionIdToSend( | 
 |           connection_->client_connection_id()); | 
 |     } | 
 |   } | 
 |   return config_.FillTransportParameters(params); | 
 | } | 
 |  | 
 | QuicErrorCode QuicSession::ProcessTransportParameters( | 
 |     const TransportParameters& params, bool is_resumption, | 
 |     std::string* error_details) { | 
 |   return config_.ProcessTransportParameters(params, is_resumption, | 
 |                                             error_details); | 
 | } | 
 |  | 
 | void QuicSession::OnHandshakeCallbackDone() { | 
 |   if (!connection_->connected()) { | 
 |     return; | 
 |   } | 
 |  | 
 |   if (!connection()->is_processing_packet()) { | 
 |     connection()->MaybeProcessUndecryptablePackets(); | 
 |   } | 
 | } | 
 |  | 
 | bool QuicSession::PacketFlusherAttached() const { | 
 |   QUICHE_DCHECK(connection_->connected()); | 
 |   return connection()->packet_creator().PacketFlusherAttached(); | 
 | } | 
 |  | 
 | void QuicSession::OnEncryptedClientHelloSent( | 
 |     absl::string_view client_hello) const { | 
 |   connection()->OnEncryptedClientHelloSent(client_hello); | 
 | } | 
 |  | 
 | void QuicSession::OnEncryptedClientHelloReceived( | 
 |     absl::string_view client_hello) const { | 
 |   connection()->OnEncryptedClientHelloReceived(client_hello); | 
 | } | 
 |  | 
 | void QuicSession::OnCryptoHandshakeMessageSent( | 
 |     const CryptoHandshakeMessage& /*message*/) {} | 
 |  | 
 | void QuicSession::OnCryptoHandshakeMessageReceived( | 
 |     const CryptoHandshakeMessage& /*message*/) {} | 
 |  | 
 | void QuicSession::RegisterStreamPriority(QuicStreamId id, bool is_static, | 
 |                                          const QuicStreamPriority& priority) { | 
 |   write_blocked_streams()->RegisterStream(id, is_static, priority); | 
 | } | 
 |  | 
 | void QuicSession::UnregisterStreamPriority(QuicStreamId id) { | 
 |   write_blocked_streams()->UnregisterStream(id); | 
 | } | 
 |  | 
 | void QuicSession::UpdateStreamPriority(QuicStreamId id, | 
 |                                        const QuicStreamPriority& new_priority) { | 
 |   write_blocked_streams()->UpdateStreamPriority(id, new_priority); | 
 | } | 
 |  | 
 | void QuicSession::ActivateStream(std::unique_ptr<QuicStream> stream) { | 
 |   const bool should_keep_alive = ShouldKeepConnectionAlive(); | 
 |   QuicStreamId stream_id = stream->id(); | 
 |   bool is_static = stream->is_static(); | 
 |   QUIC_DVLOG(1) << ENDPOINT << "num_streams: " << stream_map_.size() | 
 |                 << ". activating stream " << stream_id; | 
 |   QUICHE_DCHECK(!stream_map_.contains(stream_id)); | 
 |   stream_map_[stream_id] = std::move(stream); | 
 |   if (is_static) { | 
 |     ++num_static_streams_; | 
 |     return; | 
 |   } | 
 |   if (version().HasIetfQuicFrames() && IsIncomingStream(stream_id) && | 
 |       max_streams_accepted_per_loop_ != kMaxQuicStreamCount) { | 
 |     QUICHE_DCHECK(!ExceedsPerLoopStreamLimit()); | 
 |     // Per-loop stream limit is emposed. | 
 |     ++new_incoming_streams_in_current_loop_; | 
 |     if (!stream_count_reset_alarm_->IsSet()) { | 
 |       stream_count_reset_alarm_->Set(connection()->clock()->ApproximateNow()); | 
 |     } | 
 |   } | 
 |   if (!VersionHasIetfQuicFrames(transport_version())) { | 
 |     // Do not inform stream ID manager of static streams. | 
 |     stream_id_manager_.ActivateStream( | 
 |         /*is_incoming=*/IsIncomingStream(stream_id)); | 
 |   } | 
 |   if (perspective() == Perspective::IS_CLIENT && | 
 |       connection()->multi_port_stats() != nullptr && !should_keep_alive && | 
 |       ShouldKeepConnectionAlive()) { | 
 |     connection()->MaybeProbeMultiPortPath(); | 
 |   } | 
 | } | 
 |  | 
 | QuicStreamId QuicSession::GetNextOutgoingBidirectionalStreamId() { | 
 |   if (VersionHasIetfQuicFrames(transport_version())) { | 
 |     return ietf_streamid_manager_.GetNextOutgoingBidirectionalStreamId(); | 
 |   } | 
 |   return stream_id_manager_.GetNextOutgoingStreamId(); | 
 | } | 
 |  | 
 | QuicStreamId QuicSession::GetNextOutgoingUnidirectionalStreamId() { | 
 |   if (VersionHasIetfQuicFrames(transport_version())) { | 
 |     return ietf_streamid_manager_.GetNextOutgoingUnidirectionalStreamId(); | 
 |   } | 
 |   return stream_id_manager_.GetNextOutgoingStreamId(); | 
 | } | 
 |  | 
 | bool QuicSession::CanOpenNextOutgoingBidirectionalStream() { | 
 |   if (liveness_testing_in_progress_) { | 
 |     QUICHE_DCHECK_EQ(Perspective::IS_CLIENT, perspective()); | 
 |     QUIC_CODE_COUNT( | 
 |         quic_client_fails_to_create_stream_liveness_testing_in_progress); | 
 |     return false; | 
 |   } | 
 |   if (!VersionHasIetfQuicFrames(transport_version())) { | 
 |     if (!stream_id_manager_.CanOpenNextOutgoingStream()) { | 
 |       return false; | 
 |     } | 
 |   } else { | 
 |     if (!ietf_streamid_manager_.CanOpenNextOutgoingBidirectionalStream()) { | 
 |       QUIC_CODE_COUNT( | 
 |           quic_fails_to_create_stream_close_too_many_streams_created); | 
 |       if (is_configured_) { | 
 |         // Send STREAM_BLOCKED after config negotiated. | 
 |         control_frame_manager_.WriteOrBufferStreamsBlocked( | 
 |             ietf_streamid_manager_.max_outgoing_bidirectional_streams(), | 
 |             /*unidirectional=*/false); | 
 |       } | 
 |       return false; | 
 |     } | 
 |   } | 
 |   if (perspective() == Perspective::IS_CLIENT && | 
 |       connection_->MaybeTestLiveness()) { | 
 |     // Now is relatively close to the idle timeout having the risk that requests | 
 |     // could be discarded at the server. | 
 |     liveness_testing_in_progress_ = true; | 
 |     QUIC_CODE_COUNT(quic_client_fails_to_create_stream_close_to_idle_timeout); | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicSession::CanOpenNextOutgoingUnidirectionalStream() { | 
 |   if (!VersionHasIetfQuicFrames(transport_version())) { | 
 |     return stream_id_manager_.CanOpenNextOutgoingStream(); | 
 |   } | 
 |   if (ietf_streamid_manager_.CanOpenNextOutgoingUnidirectionalStream()) { | 
 |     return true; | 
 |   } | 
 |   if (is_configured_) { | 
 |     // Send STREAM_BLOCKED after config negotiated. | 
 |     control_frame_manager_.WriteOrBufferStreamsBlocked( | 
 |         ietf_streamid_manager_.max_outgoing_unidirectional_streams(), | 
 |         /*unidirectional=*/true); | 
 |   } | 
 |   return false; | 
 | } | 
 |  | 
 | QuicStreamCount QuicSession::GetAdvertisedMaxIncomingBidirectionalStreams() | 
 |     const { | 
 |   QUICHE_DCHECK(VersionHasIetfQuicFrames(transport_version())); | 
 |   return ietf_streamid_manager_.advertised_max_incoming_bidirectional_streams(); | 
 | } | 
 |  | 
 | QuicStream* QuicSession::GetOrCreateStream(const QuicStreamId stream_id) { | 
 |   QUICHE_DCHECK(!pending_stream_map_.contains(stream_id)); | 
 |   if (QuicUtils::IsCryptoStreamId(transport_version(), stream_id)) { | 
 |     return GetMutableCryptoStream(); | 
 |   } | 
 |  | 
 |   StreamMap::iterator it = stream_map_.find(stream_id); | 
 |   if (it != stream_map_.end()) { | 
 |     return it->second->IsZombie() ? nullptr : 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 (transport_goaway_sent_)") and B) reject stream | 
 |   // creation ("return nullptr") | 
 |  | 
 |   if (!MaybeIncreaseLargestPeerStreamId(stream_id)) { | 
 |     return nullptr; | 
 |   } | 
 |  | 
 |   if (!VersionHasIetfQuicFrames(transport_version()) && | 
 |       !stream_id_manager_.CanOpenIncomingStream()) { | 
 |     // Refuse to open the stream. | 
 |     ResetStream(stream_id, QUIC_REFUSED_STREAM); | 
 |     return nullptr; | 
 |   } | 
 |  | 
 |   return CreateIncomingStream(stream_id); | 
 | } | 
 |  | 
 | void QuicSession::StreamDraining(QuicStreamId stream_id, bool unidirectional) { | 
 |   QUICHE_DCHECK(stream_map_.contains(stream_id)); | 
 |   QUIC_DVLOG(1) << ENDPOINT << "Stream " << stream_id << " is draining"; | 
 |   if (VersionHasIetfQuicFrames(transport_version())) { | 
 |     ietf_streamid_manager_.OnStreamClosed(stream_id); | 
 |   } else { | 
 |     stream_id_manager_.OnStreamClosed( | 
 |         /*is_incoming=*/IsIncomingStream(stream_id)); | 
 |   } | 
 |   ++num_draining_streams_; | 
 |   if (!IsIncomingStream(stream_id)) { | 
 |     ++num_outgoing_draining_streams_; | 
 |     if (!VersionHasIetfQuicFrames(transport_version())) { | 
 |       OnCanCreateNewOutgoingStream(unidirectional); | 
 |     } | 
 |   } | 
 | } | 
 |  | 
 | bool QuicSession::MaybeIncreaseLargestPeerStreamId( | 
 |     const QuicStreamId stream_id) { | 
 |   if (VersionHasIetfQuicFrames(transport_version())) { | 
 |     std::string error_details; | 
 |     if (ietf_streamid_manager_.MaybeIncreaseLargestPeerStreamId( | 
 |             stream_id, &error_details)) { | 
 |       return true; | 
 |     } | 
 |     connection()->CloseConnection( | 
 |         QUIC_INVALID_STREAM_ID, error_details, | 
 |         ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     return false; | 
 |   } | 
 |   if (!stream_id_manager_.MaybeIncreaseLargestPeerStreamId(stream_id)) { | 
 |     connection()->CloseConnection( | 
 |         QUIC_TOO_MANY_AVAILABLE_STREAMS, | 
 |         absl::StrCat(stream_id, " exceeds available streams ", | 
 |                      stream_id_manager_.MaxAvailableStreams()), | 
 |         ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |     return false; | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | 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 = std::make_unique<PendingStream>(stream_id, this); | 
 |   PendingStream* unowned_pending = pending.get(); | 
 |   pending_stream_map_[stream_id] = std::move(pending); | 
 |   return unowned_pending; | 
 | } | 
 |  | 
 | void QuicSession::set_largest_peer_created_stream_id( | 
 |     QuicStreamId largest_peer_created_stream_id) { | 
 |   QUICHE_DCHECK(!VersionHasIetfQuicFrames(transport_version())); | 
 |   stream_id_manager_.set_largest_peer_created_stream_id( | 
 |       largest_peer_created_stream_id); | 
 | } | 
 |  | 
 | QuicStreamId QuicSession::GetLargestPeerCreatedStreamId( | 
 |     bool unidirectional) const { | 
 |   // This method is only used in IETF QUIC. | 
 |   QUICHE_DCHECK(VersionHasIetfQuicFrames(transport_version())); | 
 |   return ietf_streamid_manager_.GetLargestPeerCreatedStreamId(unidirectional); | 
 | } | 
 |  | 
 | void QuicSession::DeleteConnection() { | 
 |   if (connection_) { | 
 |     delete connection_; | 
 |     connection_ = nullptr; | 
 |   } | 
 | } | 
 |  | 
 | bool QuicSession::MaybeSetStreamPriority(QuicStreamId stream_id, | 
 |                                          const QuicStreamPriority& priority) { | 
 |   auto active_stream = stream_map_.find(stream_id); | 
 |   if (active_stream != stream_map_.end()) { | 
 |     active_stream->second->SetPriority(priority); | 
 |     return true; | 
 |   } | 
 |  | 
 |   return false; | 
 | } | 
 |  | 
 | bool QuicSession::IsClosedStream(QuicStreamId id) { | 
 |   QUICHE_DCHECK_NE(QuicUtils::GetInvalidStreamId(transport_version()), id); | 
 |   if (IsOpenStream(id)) { | 
 |     // Stream is active | 
 |     return false; | 
 |   } | 
 |  | 
 |   if (VersionHasIetfQuicFrames(transport_version())) { | 
 |     return !ietf_streamid_manager_.IsAvailableStream(id); | 
 |   } | 
 |  | 
 |   return !stream_id_manager_.IsAvailableStream(id); | 
 | } | 
 |  | 
 | bool QuicSession::IsOpenStream(QuicStreamId id) { | 
 |   QUICHE_DCHECK_NE(QuicUtils::GetInvalidStreamId(transport_version()), id); | 
 |   const StreamMap::iterator it = stream_map_.find(id); | 
 |   if (it != stream_map_.end()) { | 
 |     return !it->second->IsZombie(); | 
 |   } | 
 |   if (pending_stream_map_.contains(id) || | 
 |       QuicUtils::IsCryptoStreamId(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::GetNumActiveStreams() const { | 
 |   QUICHE_DCHECK_GE( | 
 |       static_cast<QuicStreamCount>(stream_map_.size()), | 
 |       num_static_streams_ + num_draining_streams_ + num_zombie_streams_); | 
 |   return stream_map_.size() - num_draining_streams_ - num_static_streams_ - | 
 |          num_zombie_streams_; | 
 | } | 
 |  | 
 | bool QuicSession::MarkConnectionLevelWriteBlocked(QuicStreamId id) { | 
 |   bool ok = true; | 
 |   if (GetOrCreateStream(id) == nullptr) { | 
 |     ok = false; | 
 |     QUIC_BUG(quic_bug_10866_11) | 
 |         << "Marking unknown stream " << id << " blocked."; | 
 |   } | 
 |  | 
 |   QUIC_DVLOG(1) << ENDPOINT << "Adding stream " << id | 
 |                 << " to write-blocked list"; | 
 |  | 
 |   write_blocked_streams_->AddStream(id); | 
 |   return ok; | 
 | } | 
 |  | 
 | 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::SendAckFrequency(const QuicAckFrequencyFrame& frame) { | 
 |   control_frame_manager_.WriteOrBufferAckFrequency(frame); | 
 | } | 
 |  | 
 | void QuicSession::SendNewConnectionId(const QuicNewConnectionIdFrame& frame) { | 
 |   control_frame_manager_.WriteOrBufferNewConnectionId( | 
 |       frame.connection_id, frame.sequence_number, frame.retire_prior_to, | 
 |       frame.stateless_reset_token); | 
 | } | 
 |  | 
 | void QuicSession::SendRetireConnectionId(uint64_t sequence_number) { | 
 |   if (GetQuicReloadableFlag( | 
 |           quic_no_write_control_frame_upon_connection_close2)) { | 
 |     QUIC_RELOADABLE_FLAG_COUNT( | 
 |         quic_no_write_control_frame_upon_connection_close2); | 
 |     if (!connection_->connected()) { | 
 |       return; | 
 |     } | 
 |   } | 
 |   control_frame_manager_.WriteOrBufferRetireConnectionId(sequence_number); | 
 | } | 
 |  | 
 | bool QuicSession::MaybeReserveConnectionId( | 
 |     const QuicConnectionId& server_connection_id) { | 
 |   if (visitor_) { | 
 |     return visitor_->TryAddNewConnectionId( | 
 |         connection_->GetOneActiveServerConnectionId(), server_connection_id); | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | void QuicSession::OnServerConnectionIdRetired( | 
 |     const QuicConnectionId& server_connection_id) { | 
 |   if (visitor_) { | 
 |     visitor_->OnConnectionIdRetired(server_connection_id); | 
 |   } | 
 | } | 
 |  | 
 | bool QuicSession::IsConnectionFlowControlBlocked() const { | 
 |   return flow_controller_.IsBlocked(); | 
 | } | 
 |  | 
 | bool QuicSession::IsStreamFlowControlBlocked() { | 
 |   for (auto const& kv : stream_map_) { | 
 |     if (kv.second->IsFlowControlBlocked()) { | 
 |       return true; | 
 |     } | 
 |   } | 
 |   if (!QuicVersionUsesCryptoFrames(transport_version()) && | 
 |       GetMutableCryptoStream()->IsFlowControlBlocked()) { | 
 |     return true; | 
 |   } | 
 |   return false; | 
 | } | 
 |  | 
 | size_t QuicSession::MaxAvailableBidirectionalStreams() const { | 
 |   if (VersionHasIetfQuicFrames(transport_version())) { | 
 |     return ietf_streamid_manager_.GetMaxAllowdIncomingBidirectionalStreams(); | 
 |   } | 
 |   return stream_id_manager_.MaxAvailableStreams(); | 
 | } | 
 |  | 
 | size_t QuicSession::MaxAvailableUnidirectionalStreams() const { | 
 |   if (VersionHasIetfQuicFrames(transport_version())) { | 
 |     return ietf_streamid_manager_.GetMaxAllowdIncomingUnidirectionalStreams(); | 
 |   } | 
 |   return stream_id_manager_.MaxAvailableStreams(); | 
 | } | 
 |  | 
 | bool QuicSession::IsIncomingStream(QuicStreamId id) const { | 
 |   if (VersionHasIetfQuicFrames(transport_version())) { | 
 |     return !QuicUtils::IsOutgoingStreamId(version(), id, perspective_); | 
 |   } | 
 |   return stream_id_manager_.IsIncomingStream(id); | 
 | } | 
 |  | 
 | void QuicSession::MaybeCloseZombieStream(QuicStreamId id) { | 
 |   auto it = stream_map_.find(id); | 
 |   if (it == stream_map_.end()) { | 
 |     return; | 
 |   } | 
 |   --num_zombie_streams_; | 
 |   PrepareStreamForDestruction(it); | 
 |  | 
 |   if (!closed_streams_clean_up_alarm_->IsSet()) { | 
 |     closed_streams_clean_up_alarm_->Set(connection_->clock()->ApproximateNow()); | 
 |   } | 
 |   // Do not retransmit data of a closed stream. | 
 |   streams_with_pending_retransmission_.erase(id); | 
 |   connection_->QuicBugIfHasPendingFrames(id); | 
 | } | 
 |  | 
 | QuicStream* QuicSession::GetStream(QuicStreamId id) const { | 
 |   auto active_stream = stream_map_.find(id); | 
 |   if (active_stream != stream_map_.end()) { | 
 |     return active_stream->second.get(); | 
 |   } | 
 |  | 
 |   if (QuicUtils::IsCryptoStreamId(transport_version(), id)) { | 
 |     return const_cast<QuicCryptoStream*>(GetCryptoStream()); | 
 |   } | 
 |  | 
 |   return nullptr; | 
 | } | 
 |  | 
 | QuicStream* QuicSession::GetActiveStream(QuicStreamId id) const { | 
 |   auto stream = stream_map_.find(id); | 
 |   if (stream != stream_map_.end() && !stream->second->is_static()) { | 
 |     return stream->second.get(); | 
 |   } | 
 |   return nullptr; | 
 | } | 
 |  | 
 | bool QuicSession::OnFrameAcked(const QuicFrame& frame, | 
 |                                QuicTime::Delta ack_delay_time, | 
 |                                QuicTime receive_timestamp, | 
 |                                bool is_retransmission) { | 
 |   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) { | 
 |     bool acked = control_frame_manager_.OnControlFrameAcked(frame); | 
 |     if (acked && frame.type == MAX_STREAMS_FRAME) { | 
 |       // Since there is a 2 frame limit on the number of outstanding max_streams | 
 |       // frames, when an outstanding max_streams frame is ack'd that frees up | 
 |       // room to potntially send another. | 
 |       ietf_streamid_manager_.MaybeSendMaxStreamsFrame(); | 
 |     } | 
 |     return acked; | 
 |   } | 
 |   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, receive_timestamp, | 
 |         &newly_acked_length, is_retransmission); | 
 |     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(quic_bug_10866_12) | 
 |         << "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) { | 
 |     ++total_datagrams_lost_; | 
 |     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() && | 
 |       !streams_with_pending_retransmission_.contains( | 
 |           frame.stream_frame.stream_id)) { | 
 |     streams_with_pending_retransmission_.insert( | 
 |         std::make_pair(frame.stream_frame.stream_id, true)); | 
 |   } | 
 | } | 
 |  | 
 | bool QuicSession::RetransmitFrames(const QuicFrames& frames, | 
 |                                    TransmissionType type) { | 
 |   QuicConnection::ScopedPacketFlusher retransmission_flusher(connection_); | 
 |   for (const QuicFrame& frame : frames) { | 
 |     if (frame.type == MESSAGE_FRAME) { | 
 |       // Do not retransmit MESSAGE frames. | 
 |       continue; | 
 |     } | 
 |     if (frame.type == CRYPTO_FRAME) { | 
 |       if (!GetMutableCryptoStream()->RetransmitData(frame.crypto_frame, type)) { | 
 |         return false; | 
 |       } | 
 |       continue; | 
 |     } | 
 |     if (frame.type != STREAM_FRAME) { | 
 |       if (!control_frame_manager_.RetransmitControlFrame(frame, type)) { | 
 |         return false; | 
 |       } | 
 |       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, type)) { | 
 |       return false; | 
 |     } | 
 |   } | 
 |   return true; | 
 | } | 
 |  | 
 | 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 { | 
 |   for (const auto& it : stream_map_) { | 
 |     if (it.second->IsWaitingForAcks()) { | 
 |       return true; | 
 |     } | 
 |   } | 
 |   return false; | 
 | } | 
 |  | 
 | HandshakeState QuicSession::GetHandshakeState() const { | 
 |   return GetCryptoStream()->GetHandshakeState(); | 
 | } | 
 |  | 
 | QuicByteCount QuicSession::GetFlowControlSendWindowSize(QuicStreamId id) { | 
 |   auto it = stream_map_.find(id); | 
 |   if (it == stream_map_.end()) { | 
 |     // No flow control for invalid or inactive stream ids. Returning uint64max | 
 |     // allows QuicPacketCreator to write as much data as possible. | 
 |     return std::numeric_limits<QuicByteCount>::max(); | 
 |   } | 
 |   return it->second->CalculateSendWindowSize(); | 
 | } | 
 |  | 
 | 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(quic_bug_10866_13) | 
 |         << "Stream " << id << " does not exist when trying to write data." | 
 |         << " version:" << 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); | 
 | } | 
 |  | 
 | StatelessResetToken QuicSession::GetStatelessResetToken() const { | 
 |   return QuicUtils::GenerateStatelessResetToken(connection_->connection_id()); | 
 | } | 
 |  | 
 | bool QuicSession::CanWriteStreamData() const { | 
 |   // Don't write stream data if there are queued data packets. | 
 |   if (connection_->HasQueuedPackets()) { | 
 |     return false; | 
 |   } | 
 |   // Immediately write handshake data. | 
 |   if (HasPendingHandshake()) { | 
 |     return true; | 
 |   } | 
 |   return connection_->CanWrite(HAS_RETRANSMITTABLE_DATA); | 
 | } | 
 |  | 
 | bool QuicSession::RetransmitLostData() { | 
 |   QuicConnection::ScopedPacketFlusher retransmission_flusher(connection_); | 
 |   // Retransmit crypto data first. | 
 |   bool uses_crypto_frames = QuicVersionUsesCryptoFrames(transport_version()); | 
 |   if (QuicCryptoStream* const crypto_stream = GetMutableCryptoStream(); | 
 |       uses_crypto_frames && crypto_stream->HasPendingCryptoRetransmission()) { | 
 |     crypto_stream->WritePendingCryptoRetransmission(); | 
 |   } | 
 |   // Retransmit crypto data in stream 1 frames (version < 47). | 
 |   if (!uses_crypto_frames && | 
 |       streams_with_pending_retransmission_.contains( | 
 |           QuicUtils::GetCryptoStreamId(transport_version()))) { | 
 |     // Retransmit crypto data first. | 
 |     QuicStream* const crypto_stream = | 
 |         GetStream(QuicUtils::GetCryptoStreamId(transport_version())); | 
 |     crypto_stream->OnCanWrite(); | 
 |     QUICHE_DCHECK(CheckStreamWriteBlocked(crypto_stream)); | 
 |     if (crypto_stream->HasPendingRetransmission()) { | 
 |       // Connection is write blocked. | 
 |       return false; | 
 |     } else { | 
 |       streams_with_pending_retransmission_.erase( | 
 |           QuicUtils::GetCryptoStreamId(transport_version())); | 
 |     } | 
 |   } | 
 |   if (control_frame_manager_.HasPendingRetransmission()) { | 
 |     control_frame_manager_.OnCanWrite(); | 
 |     if (control_frame_manager_.HasPendingRetransmission()) { | 
 |       return false; | 
 |     } | 
 |   } | 
 |   while (!streams_with_pending_retransmission_.empty()) { | 
 |     if (!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) { | 
 |       stream->OnCanWrite(); | 
 |       QUICHE_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(quic_bug_10866_14) | 
 |           << "Try to retransmit data of a closed stream"; | 
 |       streams_with_pending_retransmission_.pop_front(); | 
 |     } | 
 |   } | 
 |  | 
 |   return streams_with_pending_retransmission_.empty(); | 
 | } | 
 |  | 
 | void QuicSession::NeuterUnencryptedData() { | 
 |   QuicCryptoStream* crypto_stream = GetMutableCryptoStream(); | 
 |   crypto_stream->NeuterUnencryptedStreamData(); | 
 |   if (!crypto_stream->HasPendingRetransmission() && | 
 |       !QuicVersionUsesCryptoFrames(transport_version())) { | 
 |     streams_with_pending_retransmission_.erase( | 
 |         QuicUtils::GetCryptoStreamId(transport_version())); | 
 |   } | 
 |   connection_->NeuterUnencryptedPackets(); | 
 | } | 
 |  | 
 | void QuicSession::SetTransmissionType(TransmissionType type) { | 
 |   connection_->SetTransmissionType(type); | 
 | } | 
 |  | 
 | MessageResult QuicSession::SendMessage( | 
 |     absl::Span<quiche::QuicheMemSlice> message) { | 
 |   return SendMessage(message, /*flush=*/false); | 
 | } | 
 |  | 
 | MessageResult QuicSession::SendMessage(quiche::QuicheMemSlice message) { | 
 |   return SendMessage(absl::MakeSpan(&message, 1), /*flush=*/false); | 
 | } | 
 |  | 
 | MessageResult QuicSession::SendMessage( | 
 |     absl::Span<quiche::QuicheMemSlice> message, bool flush) { | 
 |   QUICHE_DCHECK(connection_->connected()) | 
 |       << ENDPOINT << "Try to write messages when connection is closed."; | 
 |   if (!IsEncryptionEstablished()) { | 
 |     return {MESSAGE_STATUS_ENCRYPTION_NOT_ESTABLISHED, 0}; | 
 |   } | 
 |   QuicConnection::ScopedEncryptionLevelContext context( | 
 |       connection(), GetEncryptionLevelToSendApplicationData()); | 
 |   MessageStatus result = | 
 |       connection_->SendMessage(last_message_id_ + 1, message, flush); | 
 |   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(); } | 
 |  | 
 | QuicPacketLength QuicSession::GetCurrentLargestMessagePayload() const { | 
 |   return connection_->GetCurrentLargestMessagePayload(); | 
 | } | 
 |  | 
 | QuicPacketLength QuicSession::GetGuaranteedLargestMessagePayload() const { | 
 |   return connection_->GetGuaranteedLargestMessagePayload(); | 
 | } | 
 |  | 
 | QuicStreamId QuicSession::next_outgoing_bidirectional_stream_id() const { | 
 |   if (VersionHasIetfQuicFrames(transport_version())) { | 
 |     return ietf_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(transport_version())) { | 
 |     return ietf_streamid_manager_.next_outgoing_unidirectional_stream_id(); | 
 |   } | 
 |   return stream_id_manager_.next_outgoing_stream_id(); | 
 | } | 
 |  | 
 | bool QuicSession::OnMaxStreamsFrame(const QuicMaxStreamsFrame& frame) { | 
 |   const bool allow_new_streams = | 
 |       frame.unidirectional | 
 |           ? ietf_streamid_manager_.MaybeAllowNewOutgoingUnidirectionalStreams( | 
 |                 frame.stream_count) | 
 |           : ietf_streamid_manager_.MaybeAllowNewOutgoingBidirectionalStreams( | 
 |                 frame.stream_count); | 
 |   if (allow_new_streams) { | 
 |     OnCanCreateNewOutgoingStream(frame.unidirectional); | 
 |   } | 
 |  | 
 |   return true; | 
 | } | 
 |  | 
 | bool QuicSession::OnStreamsBlockedFrame(const QuicStreamsBlockedFrame& frame) { | 
 |   std::string error_details; | 
 |   if (ietf_streamid_manager_.OnStreamsBlockedFrame(frame, &error_details)) { | 
 |     return true; | 
 |   } | 
 |   connection_->CloseConnection( | 
 |       QUIC_STREAMS_BLOCKED_ERROR, error_details, | 
 |       ConnectionCloseBehavior::SEND_CONNECTION_CLOSE_PACKET); | 
 |   return false; | 
 | } | 
 |  | 
 | size_t QuicSession::max_open_incoming_bidirectional_streams() const { | 
 |   if (VersionHasIetfQuicFrames(transport_version())) { | 
 |     return ietf_streamid_manager_.GetMaxAllowdIncomingBidirectionalStreams(); | 
 |   } | 
 |   return stream_id_manager_.max_open_incoming_streams(); | 
 | } | 
 |  | 
 | size_t QuicSession::max_open_incoming_unidirectional_streams() const { | 
 |   if (VersionHasIetfQuicFrames(transport_version())) { | 
 |     return ietf_streamid_manager_.GetMaxAllowdIncomingUnidirectionalStreams(); | 
 |   } | 
 |   return stream_id_manager_.max_open_incoming_streams(); | 
 | } | 
 |  | 
 | std::vector<absl::string_view>::const_iterator QuicSession::SelectAlpn( | 
 |     const std::vector<absl::string_view>& alpns) const { | 
 |   const std::string alpn = AlpnForVersion(connection()->version()); | 
 |   return std::find(alpns.cbegin(), alpns.cend(), alpn); | 
 | } | 
 |  | 
 | void QuicSession::OnAlpnSelected(absl::string_view alpn) { | 
 |   QUIC_DLOG(INFO) << (perspective() == Perspective::IS_SERVER ? "Server: " | 
 |                                                               : "Client: ") | 
 |                   << "ALPN selected: " << alpn; | 
 | } | 
 |  | 
 | void QuicSession::NeuterCryptoDataOfEncryptionLevel(EncryptionLevel level) { | 
 |   GetMutableCryptoStream()->NeuterStreamDataOfEncryptionLevel(level); | 
 | } | 
 |  | 
 | void QuicSession::PerformActionOnActiveStreams( | 
 |     quiche::UnretainedCallback<bool(QuicStream*)> action) { | 
 |   std::vector<QuicStream*> active_streams; | 
 |   for (const auto& it : stream_map_) { | 
 |     if (!it.second->is_static() && !it.second->IsZombie()) { | 
 |       active_streams.push_back(it.second.get()); | 
 |     } | 
 |   } | 
 |  | 
 |   for (QuicStream* stream : active_streams) { | 
 |     if (!action(stream)) { | 
 |       return; | 
 |     } | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::PerformActionOnNonStaticStreams( | 
 |     quiche::UnretainedCallback<bool(QuicStream*)> action) { | 
 |   std::vector<QuicStream*> streams; | 
 |   for (const auto& it : stream_map_) { | 
 |     if (!it.second->is_static()) { | 
 |       streams.push_back(it.second.get()); | 
 |     } | 
 |   } | 
 |  | 
 |   for (QuicStream* stream : streams) { | 
 |     if (!action(stream)) { | 
 |       return; | 
 |     } | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::PerformActionOnActiveStreams( | 
 |     quiche::UnretainedCallback<bool(QuicStream*)> action) const { | 
 |   for (const auto& it : stream_map_) { | 
 |     if (!it.second->is_static() && !it.second->IsZombie() && | 
 |         !action(it.second.get())) { | 
 |       return; | 
 |     } | 
 |   } | 
 | } | 
 |  | 
 | EncryptionLevel QuicSession::GetEncryptionLevelToSendApplicationData() const { | 
 |   return connection_->framer().GetEncryptionLevelToSendApplicationData(); | 
 | } | 
 |  | 
 | void QuicSession::ProcessAllPendingStreams() { | 
 |   std::vector<PendingStream*> pending_streams; | 
 |   pending_streams.reserve(pending_stream_map_.size()); | 
 |   for (auto it = pending_stream_map_.begin(); it != pending_stream_map_.end(); | 
 |        ++it) { | 
 |     pending_streams.push_back(it->second.get()); | 
 |   } | 
 |   for (auto* pending_stream : pending_streams) { | 
 |     if (!MaybeProcessPendingStream(pending_stream)) { | 
 |       // Defer any further pending stream processing to the next event loop. | 
 |       return; | 
 |     } | 
 |   } | 
 | } | 
 |  | 
 | void QuicSession::ValidatePath( | 
 |     std::unique_ptr<QuicPathValidationContext> context, | 
 |     std::unique_ptr<QuicPathValidator::ResultDelegate> result_delegate, | 
 |     PathValidationReason reason) { | 
 |   connection_->ValidatePath(std::move(context), std::move(result_delegate), | 
 |                             reason); | 
 | } | 
 |  | 
 | bool QuicSession::HasPendingPathValidation() const { | 
 |   return connection_->HasPendingPathValidation(); | 
 | } | 
 |  | 
 | bool QuicSession::MigratePath(const QuicSocketAddress& self_address, | 
 |                               const QuicSocketAddress& peer_address, | 
 |                               QuicPacketWriter* writer, bool owns_writer) { | 
 |   return connection_->MigratePath(self_address, peer_address, writer, | 
 |                                   owns_writer); | 
 | } | 
 |  | 
 | bool QuicSession::ValidateToken(absl::string_view token) { | 
 |   QUICHE_DCHECK_EQ(perspective_, Perspective::IS_SERVER); | 
 |   if (GetQuicFlag(quic_reject_retry_token_in_initial_packet)) { | 
 |     return false; | 
 |   } | 
 |   if (token.empty() || token[0] != kAddressTokenPrefix) { | 
 |     // Validate the prefix for token received in NEW_TOKEN frame. | 
 |     return false; | 
 |   } | 
 |   const bool valid = GetCryptoStream()->ValidateAddressToken( | 
 |       absl::string_view(token.data() + 1, token.length() - 1)); | 
 |   if (valid) { | 
 |     const CachedNetworkParameters* cached_network_params = | 
 |         GetCryptoStream()->PreviousCachedNetworkParams(); | 
 |     if (cached_network_params != nullptr && | 
 |         cached_network_params->timestamp() > 0) { | 
 |       connection()->OnReceiveConnectionState(*cached_network_params); | 
 |     } | 
 |   } | 
 |   return valid; | 
 | } | 
 |  | 
 | void QuicSession::OnServerPreferredAddressAvailable( | 
 |     const QuicSocketAddress& server_preferred_address) { | 
 |   QUICHE_DCHECK_EQ(perspective_, Perspective::IS_CLIENT); | 
 |   if (visitor_ != nullptr) { | 
 |     visitor_->OnServerPreferredAddressAvailable(server_preferred_address); | 
 |   } | 
 | } | 
 |  | 
 | QuicStream* QuicSession::ProcessPendingStream(PendingStream* pending) { | 
 |   QUICHE_DCHECK(VersionUsesHttp3(transport_version())); | 
 |   QUICHE_DCHECK(connection()->connected()); | 
 |   QuicStreamId stream_id = pending->id(); | 
 |   QUIC_BUG_IF(bad pending stream, !IsIncomingStream(stream_id)) | 
 |       << "Pending stream " << stream_id << " is not an incoming stream."; | 
 |   // TODO(b/305051334) check if this stream is incoming stream before making it | 
 |   // pending. If not, connection should be closed. | 
 |   StreamType stream_type = QuicUtils::GetStreamType( | 
 |       stream_id, perspective(), /*peer_initiated=*/true, version()); | 
 |   switch (stream_type) { | 
 |     case BIDIRECTIONAL: { | 
 |       return ProcessBidirectionalPendingStream(pending); | 
 |     } | 
 |     case READ_UNIDIRECTIONAL: { | 
 |       return ProcessReadUnidirectionalPendingStream(pending); | 
 |     } | 
 |     case WRITE_UNIDIRECTIONAL: | 
 |       ABSL_FALLTHROUGH_INTENDED; | 
 |     case CRYPTO: | 
 |       QUICHE_BUG(unexpected pending stream) | 
 |           << "Unexpected pending stream " << stream_id << " with type " | 
 |           << stream_type; | 
 |       return nullptr; | 
 |   } | 
 |   return nullptr;  // Unreachable, unless the enum value is out-of-range | 
 |                    // (potentially undefined behavior) | 
 | } | 
 |  | 
 | bool QuicSession::ExceedsPerLoopStreamLimit() const { | 
 |   QUICHE_DCHECK(version().HasIetfQuicFrames()); | 
 |   return new_incoming_streams_in_current_loop_ >= | 
 |          max_streams_accepted_per_loop_; | 
 | } | 
 |  | 
 | void QuicSession::OnStreamCountReset() { | 
 |   const bool exceeded_per_loop_stream_limit = ExceedsPerLoopStreamLimit(); | 
 |   new_incoming_streams_in_current_loop_ = 0; | 
 |   if (exceeded_per_loop_stream_limit) { | 
 |     QUIC_CODE_COUNT_N(quic_pending_stream, 2, 3); | 
 |     // Convert as many leftover pending streams from last loop to active streams | 
 |     // as allowed. | 
 |     ProcessAllPendingStreams(); | 
 |   } | 
 | } | 
 |  | 
 | #undef ENDPOINT  // undef for jumbo builds | 
 | }  // namespace quic |