| // Copyright 2013 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "net/third_party/quiche/src/quic/core/quic_sent_packet_manager.h" |
| |
| #include <algorithm> |
| #include <string> |
| |
| #include "net/third_party/quiche/src/quic/core/congestion_control/general_loss_algorithm.h" |
| #include "net/third_party/quiche/src/quic/core/congestion_control/pacing_sender.h" |
| #include "net/third_party/quiche/src/quic/core/crypto/crypto_protocol.h" |
| #include "net/third_party/quiche/src/quic/core/proto/cached_network_parameters_proto.h" |
| #include "net/third_party/quiche/src/quic/core/quic_connection_stats.h" |
| #include "net/third_party/quiche/src/quic/core/quic_types.h" |
| #include "net/third_party/quiche/src/quic/core/quic_utils.h" |
| #include "net/third_party/quiche/src/quic/platform/api/quic_bug_tracker.h" |
| #include "net/third_party/quiche/src/quic/platform/api/quic_flag_utils.h" |
| #include "net/third_party/quiche/src/quic/platform/api/quic_flags.h" |
| #include "net/third_party/quiche/src/quic/platform/api/quic_logging.h" |
| #include "net/third_party/quiche/src/quic/platform/api/quic_map_util.h" |
| |
| namespace quic { |
| |
| namespace { |
| static const int64_t kDefaultRetransmissionTimeMs = 500; |
| static const int64_t kMaxRetransmissionTimeMs = 60000; |
| // Maximum number of exponential backoffs used for RTO timeouts. |
| static const size_t kMaxRetransmissions = 10; |
| // Maximum number of packets retransmitted upon an RTO. |
| static const size_t kMaxRetransmissionsOnTimeout = 2; |
| // The path degrading delay is the sum of this number of consecutive RTO delays. |
| const size_t kNumRetransmissionDelaysForPathDegradingDelay = 2; |
| |
| // Ensure the handshake timer isnt't faster than 10ms. |
| // This limits the tenth retransmitted packet to 10s after the initial CHLO. |
| static const int64_t kMinHandshakeTimeoutMs = 10; |
| |
| // Sends up to two tail loss probes before firing an RTO, |
| // per draft RFC draft-dukkipati-tcpm-tcp-loss-probe. |
| static const size_t kDefaultMaxTailLossProbes = 2; |
| |
| // Returns true of retransmissions of the specified type should retransmit |
| // the frames directly (as opposed to resulting in a loss notification). |
| inline bool ShouldForceRetransmission(TransmissionType transmission_type) { |
| return transmission_type == HANDSHAKE_RETRANSMISSION || |
| transmission_type == TLP_RETRANSMISSION || |
| transmission_type == PROBING_RETRANSMISSION || |
| transmission_type == RTO_RETRANSMISSION || |
| transmission_type == PTO_RETRANSMISSION; |
| } |
| |
| // If pacing rate is accurate, > 2 burst token is not likely to help first ACK |
| // to arrive earlier, and overly large burst token could cause incast packet |
| // losses. |
| static const uint32_t kConservativeUnpacedBurst = 2; |
| |
| } // namespace |
| |
| #define ENDPOINT \ |
| (unacked_packets_.perspective() == Perspective::IS_SERVER ? "Server: " \ |
| : "Client: ") |
| |
| QuicSentPacketManager::QuicSentPacketManager( |
| Perspective perspective, |
| const QuicClock* clock, |
| QuicRandom* random, |
| QuicConnectionStats* stats, |
| CongestionControlType congestion_control_type) |
| : unacked_packets_(perspective), |
| clock_(clock), |
| random_(random), |
| stats_(stats), |
| debug_delegate_(nullptr), |
| network_change_visitor_(nullptr), |
| initial_congestion_window_(kInitialCongestionWindow), |
| loss_algorithm_(&uber_loss_algorithm_), |
| consecutive_rto_count_(0), |
| consecutive_tlp_count_(0), |
| consecutive_crypto_retransmission_count_(0), |
| pending_timer_transmission_count_(0), |
| max_tail_loss_probes_(kDefaultMaxTailLossProbes), |
| max_rto_packets_(kMaxRetransmissionsOnTimeout), |
| enable_half_rtt_tail_loss_probe_(false), |
| using_pacing_(false), |
| use_new_rto_(false), |
| conservative_handshake_retransmits_(false), |
| min_tlp_timeout_( |
| QuicTime::Delta::FromMilliseconds(kMinTailLossProbeTimeoutMs)), |
| min_rto_timeout_( |
| QuicTime::Delta::FromMilliseconds(kMinRetransmissionTimeMs)), |
| largest_mtu_acked_(0), |
| handshake_finished_(false), |
| peer_max_ack_delay_( |
| QuicTime::Delta::FromMilliseconds(kDefaultDelayedAckTimeMs)), |
| rtt_updated_(false), |
| acked_packets_iter_(last_ack_frame_.packets.rbegin()), |
| pto_enabled_(GetQuicReloadableFlag(quic_default_on_pto)), |
| max_probe_packets_per_pto_(2), |
| consecutive_pto_count_(0), |
| handshake_mode_disabled_(false), |
| skip_packet_number_for_pto_(false), |
| always_include_max_ack_delay_for_pto_timeout_(true), |
| pto_exponential_backoff_start_point_(0), |
| pto_rttvar_multiplier_(4), |
| num_tlp_timeout_ptos_(0), |
| one_rtt_packet_acked_(false), |
| one_rtt_packet_sent_(false), |
| first_pto_srtt_multiplier_(0), |
| use_standard_deviation_for_pto_(false) { |
| SetSendAlgorithm(congestion_control_type); |
| if (pto_enabled_) { |
| QUIC_RELOADABLE_FLAG_COUNT_N(quic_default_on_pto, 1, 2); |
| // TODO(fayang): change the default values when deprecating |
| // quic_default_on_pto. |
| first_pto_srtt_multiplier_ = 1.5; |
| pto_rttvar_multiplier_ = 2; |
| } |
| } |
| |
| QuicSentPacketManager::~QuicSentPacketManager() {} |
| |
| void QuicSentPacketManager::SetFromConfig(const QuicConfig& config) { |
| const Perspective perspective = unacked_packets_.perspective(); |
| if (config.HasReceivedInitialRoundTripTimeUs() && |
| config.ReceivedInitialRoundTripTimeUs() > 0) { |
| if (!config.HasClientSentConnectionOption(kNRTT, perspective)) { |
| SetInitialRtt(QuicTime::Delta::FromMicroseconds( |
| config.ReceivedInitialRoundTripTimeUs())); |
| } |
| } else if (config.HasInitialRoundTripTimeUsToSend() && |
| config.GetInitialRoundTripTimeUsToSend() > 0) { |
| SetInitialRtt(QuicTime::Delta::FromMicroseconds( |
| config.GetInitialRoundTripTimeUsToSend())); |
| } |
| if (config.HasReceivedMaxAckDelayMs()) { |
| peer_max_ack_delay_ = |
| QuicTime::Delta::FromMilliseconds(config.ReceivedMaxAckDelayMs()); |
| } |
| if (config.HasClientSentConnectionOption(kMAD0, perspective)) { |
| rtt_stats_.set_ignore_max_ack_delay(true); |
| } |
| if (config.HasClientSentConnectionOption(kMAD1, perspective)) { |
| rtt_stats_.set_initial_max_ack_delay(peer_max_ack_delay_); |
| } |
| if (config.HasClientSentConnectionOption(kMAD2, perspective)) { |
| // Set the minimum to the alarm granularity. |
| min_tlp_timeout_ = kAlarmGranularity; |
| } |
| if (config.HasClientSentConnectionOption(kMAD3, perspective)) { |
| // Set the minimum to the alarm granularity. |
| min_rto_timeout_ = kAlarmGranularity; |
| } |
| |
| if (config.HasClientSentConnectionOption(k2PTO, perspective)) { |
| pto_enabled_ = true; |
| } |
| if (config.HasClientSentConnectionOption(k1PTO, perspective)) { |
| pto_enabled_ = true; |
| max_probe_packets_per_pto_ = 1; |
| } |
| |
| if (config.HasClientSentConnectionOption(kPTOS, perspective)) { |
| if (!pto_enabled_) { |
| QUIC_PEER_BUG |
| << "PTO is not enabled when receiving PTOS connection option."; |
| pto_enabled_ = true; |
| max_probe_packets_per_pto_ = 1; |
| } |
| skip_packet_number_for_pto_ = true; |
| } |
| |
| if (pto_enabled_) { |
| if (config.HasClientSentConnectionOption(kPTOA, perspective)) { |
| always_include_max_ack_delay_for_pto_timeout_ = false; |
| } |
| if (config.HasClientSentConnectionOption(kPEB1, perspective)) { |
| StartExponentialBackoffAfterNthPto(1); |
| } |
| if (config.HasClientSentConnectionOption(kPEB2, perspective)) { |
| StartExponentialBackoffAfterNthPto(2); |
| } |
| if (config.HasClientSentConnectionOption(kPVS1, perspective)) { |
| pto_rttvar_multiplier_ = 2; |
| } |
| if (config.HasClientSentConnectionOption(kPAG1, perspective)) { |
| QUIC_CODE_COUNT(one_aggressive_pto); |
| num_tlp_timeout_ptos_ = 1; |
| } |
| if (config.HasClientSentConnectionOption(kPAG2, perspective)) { |
| QUIC_CODE_COUNT(two_aggressive_ptos); |
| num_tlp_timeout_ptos_ = 2; |
| } |
| if (config.HasClientSentConnectionOption(kPLE1, perspective) || |
| config.HasClientSentConnectionOption(kTLPR, perspective)) { |
| first_pto_srtt_multiplier_ = 0.5; |
| } else if (config.HasClientSentConnectionOption(kPLE2, perspective)) { |
| first_pto_srtt_multiplier_ = 1.5; |
| } |
| if (config.HasClientSentConnectionOption(kPSDA, perspective)) { |
| use_standard_deviation_for_pto_ = true; |
| rtt_stats_.EnableStandardDeviationCalculation(); |
| } |
| } |
| |
| // Configure congestion control. |
| if (config.HasClientRequestedIndependentOption(kTBBR, perspective)) { |
| SetSendAlgorithm(kBBR); |
| } |
| if (GetQuicReloadableFlag(quic_allow_client_enabled_bbr_v2) && |
| config.HasClientRequestedIndependentOption(kB2ON, perspective)) { |
| QUIC_RELOADABLE_FLAG_COUNT(quic_allow_client_enabled_bbr_v2); |
| SetSendAlgorithm(kBBRv2); |
| } |
| |
| if (config.HasClientRequestedIndependentOption(kRENO, perspective)) { |
| SetSendAlgorithm(kRenoBytes); |
| } else if (config.HasClientRequestedIndependentOption(kBYTE, perspective) || |
| (GetQuicReloadableFlag(quic_default_to_bbr) && |
| config.HasClientRequestedIndependentOption(kQBIC, perspective))) { |
| SetSendAlgorithm(kCubicBytes); |
| } |
| |
| // Initial window. |
| if (GetQuicReloadableFlag(quic_unified_iw_options)) { |
| if (config.HasClientRequestedIndependentOption(kIW03, perspective)) { |
| initial_congestion_window_ = 3; |
| send_algorithm_->SetInitialCongestionWindowInPackets(3); |
| } |
| if (config.HasClientRequestedIndependentOption(kIW10, perspective)) { |
| initial_congestion_window_ = 10; |
| send_algorithm_->SetInitialCongestionWindowInPackets(10); |
| } |
| if (config.HasClientRequestedIndependentOption(kIW20, perspective)) { |
| initial_congestion_window_ = 20; |
| send_algorithm_->SetInitialCongestionWindowInPackets(20); |
| } |
| if (config.HasClientRequestedIndependentOption(kIW50, perspective)) { |
| initial_congestion_window_ = 50; |
| send_algorithm_->SetInitialCongestionWindowInPackets(50); |
| } |
| } |
| if (GetQuicReloadableFlag(quic_bbr_mitigate_overly_large_bandwidth_sample) && |
| config.HasClientRequestedIndependentOption(kBWS5, perspective)) { |
| initial_congestion_window_ = 10; |
| send_algorithm_->SetInitialCongestionWindowInPackets(10); |
| } |
| |
| using_pacing_ = !GetQuicFlag(FLAGS_quic_disable_pacing_for_perf_tests); |
| |
| if (config.HasClientSentConnectionOption(kNTLP, perspective)) { |
| max_tail_loss_probes_ = 0; |
| } |
| if (config.HasClientSentConnectionOption(k1TLP, perspective)) { |
| max_tail_loss_probes_ = 1; |
| } |
| if (config.HasClientSentConnectionOption(k1RTO, perspective)) { |
| max_rto_packets_ = 1; |
| } |
| if (config.HasClientSentConnectionOption(kTLPR, perspective)) { |
| enable_half_rtt_tail_loss_probe_ = true; |
| } |
| if (config.HasClientSentConnectionOption(kNRTO, perspective)) { |
| use_new_rto_ = true; |
| } |
| // Configure loss detection. |
| if (config.HasClientRequestedIndependentOption(kILD0, perspective)) { |
| uber_loss_algorithm_.SetReorderingShift(kDefaultIetfLossDelayShift); |
| uber_loss_algorithm_.DisableAdaptiveReorderingThreshold(); |
| } |
| if (config.HasClientRequestedIndependentOption(kILD1, perspective)) { |
| uber_loss_algorithm_.SetReorderingShift(kDefaultLossDelayShift); |
| uber_loss_algorithm_.DisableAdaptiveReorderingThreshold(); |
| } |
| if (config.HasClientRequestedIndependentOption(kILD2, perspective)) { |
| uber_loss_algorithm_.EnableAdaptiveReorderingThreshold(); |
| uber_loss_algorithm_.SetReorderingShift(kDefaultIetfLossDelayShift); |
| } |
| if (config.HasClientRequestedIndependentOption(kILD3, perspective)) { |
| uber_loss_algorithm_.SetReorderingShift(kDefaultLossDelayShift); |
| uber_loss_algorithm_.EnableAdaptiveReorderingThreshold(); |
| } |
| if (config.HasClientRequestedIndependentOption(kILD4, perspective)) { |
| uber_loss_algorithm_.SetReorderingShift(kDefaultLossDelayShift); |
| uber_loss_algorithm_.EnableAdaptiveReorderingThreshold(); |
| uber_loss_algorithm_.EnableAdaptiveTimeThreshold(); |
| } |
| if (config.HasClientRequestedIndependentOption(kRUNT, perspective)) { |
| uber_loss_algorithm_.DisablePacketThresholdForRuntPackets(); |
| } |
| if (config.HasClientSentConnectionOption(kCONH, perspective)) { |
| conservative_handshake_retransmits_ = true; |
| } |
| send_algorithm_->SetFromConfig(config, perspective); |
| loss_algorithm_->SetFromConfig(config, perspective); |
| |
| if (network_change_visitor_ != nullptr) { |
| network_change_visitor_->OnCongestionChange(); |
| } |
| } |
| |
| void QuicSentPacketManager::ApplyConnectionOptions( |
| const QuicTagVector& connection_options) { |
| send_algorithm_->ApplyConnectionOptions(connection_options); |
| } |
| |
| void QuicSentPacketManager::ResumeConnectionState( |
| const CachedNetworkParameters& cached_network_params, |
| bool max_bandwidth_resumption) { |
| QuicBandwidth bandwidth = QuicBandwidth::FromBytesPerSecond( |
| max_bandwidth_resumption |
| ? cached_network_params.max_bandwidth_estimate_bytes_per_second() |
| : cached_network_params.bandwidth_estimate_bytes_per_second()); |
| QuicTime::Delta rtt = |
| QuicTime::Delta::FromMilliseconds(cached_network_params.min_rtt_ms()); |
| // This calls the old AdjustNetworkParameters interface, and fills certain |
| // fields in SendAlgorithmInterface::NetworkParams |
| // (e.g., quic_bbr_fix_pacing_rate) using GFE flags. |
| AdjustNetworkParameters(SendAlgorithmInterface::NetworkParams( |
| bandwidth, rtt, /*allow_cwnd_to_decrease = */ false)); |
| } |
| |
| void QuicSentPacketManager::AdjustNetworkParameters( |
| const SendAlgorithmInterface::NetworkParams& params) { |
| const QuicBandwidth& bandwidth = params.bandwidth; |
| const QuicTime::Delta& rtt = params.rtt; |
| if (!rtt.IsZero()) { |
| SetInitialRtt(rtt); |
| } |
| const QuicByteCount old_cwnd = send_algorithm_->GetCongestionWindow(); |
| if (GetQuicReloadableFlag(quic_conservative_bursts) && using_pacing_ && |
| !bandwidth.IsZero()) { |
| QUIC_RELOADABLE_FLAG_COUNT(quic_conservative_bursts); |
| pacing_sender_.SetBurstTokens(kConservativeUnpacedBurst); |
| } |
| send_algorithm_->AdjustNetworkParameters(params); |
| if (debug_delegate_ != nullptr) { |
| debug_delegate_->OnAdjustNetworkParameters( |
| bandwidth, rtt.IsZero() ? rtt_stats_.MinOrInitialRtt() : rtt, old_cwnd, |
| send_algorithm_->GetCongestionWindow()); |
| } |
| } |
| |
| void QuicSentPacketManager::SetLossDetectionTuner( |
| std::unique_ptr<LossDetectionTunerInterface> tuner) { |
| uber_loss_algorithm_.SetLossDetectionTuner(std::move(tuner)); |
| } |
| |
| void QuicSentPacketManager::OnConfigNegotiated() { |
| loss_algorithm_->OnConfigNegotiated(); |
| } |
| |
| void QuicSentPacketManager::OnConnectionClosed() { |
| loss_algorithm_->OnConnectionClosed(); |
| } |
| |
| void QuicSentPacketManager::SetHandshakeConfirmed() { |
| if (!handshake_finished_) { |
| handshake_finished_ = true; |
| NeuterHandshakePackets(); |
| } |
| } |
| |
| void QuicSentPacketManager::PostProcessNewlyAckedPackets( |
| QuicPacketNumber ack_packet_number, |
| EncryptionLevel ack_decrypted_level, |
| const QuicAckFrame& ack_frame, |
| QuicTime ack_receive_time, |
| bool rtt_updated, |
| QuicByteCount prior_bytes_in_flight) { |
| unacked_packets_.NotifyAggregatedStreamFrameAcked( |
| last_ack_frame_.ack_delay_time); |
| InvokeLossDetection(ack_receive_time); |
| // Ignore losses in RTO mode. |
| if (consecutive_rto_count_ > 0 && !use_new_rto_) { |
| packets_lost_.clear(); |
| } |
| MaybeInvokeCongestionEvent(rtt_updated, prior_bytes_in_flight, |
| ack_receive_time); |
| unacked_packets_.RemoveObsoletePackets(); |
| |
| sustained_bandwidth_recorder_.RecordEstimate( |
| send_algorithm_->InRecovery(), send_algorithm_->InSlowStart(), |
| send_algorithm_->BandwidthEstimate(), ack_receive_time, clock_->WallNow(), |
| rtt_stats_.smoothed_rtt()); |
| |
| // Anytime we are making forward progress and have a new RTT estimate, reset |
| // the backoff counters. |
| if (rtt_updated) { |
| if (consecutive_rto_count_ > 0) { |
| // If the ack acknowledges data sent prior to the RTO, |
| // the RTO was spurious. |
| if (LargestAcked(ack_frame) < first_rto_transmission_) { |
| // Replace SRTT with latest_rtt and increase the variance to prevent |
| // a spurious RTO from happening again. |
| rtt_stats_.ExpireSmoothedMetrics(); |
| } else { |
| if (!use_new_rto_) { |
| send_algorithm_->OnRetransmissionTimeout(true); |
| } |
| } |
| } |
| // Records the max consecutive RTO or PTO before forward progress has been |
| // made. |
| if (consecutive_rto_count_ > |
| stats_->max_consecutive_rto_with_forward_progress) { |
| stats_->max_consecutive_rto_with_forward_progress = |
| consecutive_rto_count_; |
| } else if (consecutive_pto_count_ > |
| stats_->max_consecutive_rto_with_forward_progress) { |
| stats_->max_consecutive_rto_with_forward_progress = |
| consecutive_pto_count_; |
| } |
| // Reset all retransmit counters any time a new packet is acked. |
| consecutive_rto_count_ = 0; |
| consecutive_tlp_count_ = 0; |
| consecutive_pto_count_ = 0; |
| consecutive_crypto_retransmission_count_ = 0; |
| } |
| |
| if (debug_delegate_ != nullptr) { |
| debug_delegate_->OnIncomingAck( |
| ack_packet_number, ack_decrypted_level, ack_frame, ack_receive_time, |
| LargestAcked(ack_frame), rtt_updated, GetLeastUnacked()); |
| } |
| // Remove packets below least unacked from all_packets_acked_ and |
| // last_ack_frame_. |
| last_ack_frame_.packets.RemoveUpTo(unacked_packets_.GetLeastUnacked()); |
| last_ack_frame_.received_packet_times.clear(); |
| } |
| |
| void QuicSentPacketManager::MaybeInvokeCongestionEvent( |
| bool rtt_updated, |
| QuicByteCount prior_in_flight, |
| QuicTime event_time) { |
| if (!rtt_updated && packets_acked_.empty() && packets_lost_.empty()) { |
| return; |
| } |
| if (using_pacing_) { |
| pacing_sender_.OnCongestionEvent(rtt_updated, prior_in_flight, event_time, |
| packets_acked_, packets_lost_); |
| } else { |
| send_algorithm_->OnCongestionEvent(rtt_updated, prior_in_flight, event_time, |
| packets_acked_, packets_lost_); |
| } |
| packets_acked_.clear(); |
| packets_lost_.clear(); |
| if (network_change_visitor_ != nullptr) { |
| network_change_visitor_->OnCongestionChange(); |
| } |
| } |
| |
| void QuicSentPacketManager::RetransmitZeroRttPackets() { |
| QuicPacketNumber packet_number = unacked_packets_.GetLeastUnacked(); |
| for (QuicUnackedPacketMap::iterator it = unacked_packets_.begin(); |
| it != unacked_packets_.end(); ++it, ++packet_number) { |
| if (it->encryption_level == ENCRYPTION_ZERO_RTT) { |
| if (it->in_flight) { |
| // Remove 0-RTT packets and packets of the wrong version from flight, |
| // because neither can be processed by the peer. |
| unacked_packets_.RemoveFromInFlight(&*it); |
| } |
| if (unacked_packets_.HasRetransmittableFrames(*it)) { |
| MarkForRetransmission(packet_number, ALL_ZERO_RTT_RETRANSMISSION); |
| } |
| } |
| } |
| } |
| |
| void QuicSentPacketManager::NeuterUnencryptedPackets() { |
| for (QuicPacketNumber packet_number : |
| unacked_packets_.NeuterUnencryptedPackets()) { |
| send_algorithm_->OnPacketNeutered(packet_number); |
| } |
| if (handshake_mode_disabled_) { |
| consecutive_pto_count_ = 0; |
| uber_loss_algorithm_.ResetLossDetection(INITIAL_DATA); |
| } |
| } |
| |
| void QuicSentPacketManager::NeuterHandshakePackets() { |
| for (QuicPacketNumber packet_number : |
| unacked_packets_.NeuterHandshakePackets()) { |
| send_algorithm_->OnPacketNeutered(packet_number); |
| } |
| if (handshake_mode_disabled_) { |
| consecutive_pto_count_ = 0; |
| uber_loss_algorithm_.ResetLossDetection(HANDSHAKE_DATA); |
| } |
| } |
| |
| bool QuicSentPacketManager::ShouldAddMaxAckDelay() const { |
| DCHECK(pto_enabled_); |
| if (always_include_max_ack_delay_for_pto_timeout_) { |
| return true; |
| } |
| if (!unacked_packets_ |
| .GetLargestSentRetransmittableOfPacketNumberSpace(APPLICATION_DATA) |
| .IsInitialized() || |
| unacked_packets_.GetLargestSentRetransmittableOfPacketNumberSpace( |
| APPLICATION_DATA) < |
| FirstSendingPacketNumber() + kMinReceivedBeforeAckDecimation - 1) { |
| // Peer is doing TCP style acking. Expect an immediate ACK if more than 1 |
| // packet are outstanding. |
| if (unacked_packets_.packets_in_flight() >= |
| kDefaultRetransmittablePacketsBeforeAck) { |
| return false; |
| } |
| } else if (unacked_packets_.packets_in_flight() >= |
| kMaxRetransmittablePacketsBeforeAck) { |
| // Peer is doing ack decimation. Expect an immediate ACK if >= 10 |
| // packets are outstanding. |
| return false; |
| } |
| if (skip_packet_number_for_pto_ && consecutive_pto_count_ > 0) { |
| // An immediate ACK is expected when doing PTOS. Please note, this will miss |
| // cases when PTO fires and turns out to be spurious. |
| return false; |
| } |
| return true; |
| } |
| |
| QuicTime QuicSentPacketManager::GetEarliestPacketSentTimeForPto( |
| PacketNumberSpace* packet_number_space) const { |
| DCHECK(supports_multiple_packet_number_spaces()); |
| QuicTime earliest_sent_time = QuicTime::Zero(); |
| for (int8_t i = 0; i < NUM_PACKET_NUMBER_SPACES; ++i) { |
| const QuicTime sent_time = unacked_packets_.GetLastInFlightPacketSentTime( |
| static_cast<PacketNumberSpace>(i)); |
| if (!ShouldArmPtoForApplicationData() && i == APPLICATION_DATA) { |
| continue; |
| } |
| if (!sent_time.IsInitialized() || (earliest_sent_time.IsInitialized() && |
| earliest_sent_time <= sent_time)) { |
| continue; |
| } |
| earliest_sent_time = sent_time; |
| *packet_number_space = static_cast<PacketNumberSpace>(i); |
| } |
| |
| return earliest_sent_time; |
| } |
| |
| bool QuicSentPacketManager::ShouldArmPtoForApplicationData() const { |
| DCHECK(supports_multiple_packet_number_spaces()); |
| // Application data must be ignored before handshake completes (1-RTT key |
| // is available). Not arming PTO for application data to prioritize the |
| // completion of handshake. On the server side, handshake_finished_ |
| // indicates handshake complete (and confirmed). On the client side, |
| // one_rtt_packet_sent_ indicates handshake complete (while handshake |
| // confirmation will happen later). |
| return handshake_finished_ || |
| (unacked_packets_.perspective() == Perspective::IS_CLIENT && |
| one_rtt_packet_sent_); |
| } |
| |
| void QuicSentPacketManager::MarkForRetransmission( |
| QuicPacketNumber packet_number, |
| TransmissionType transmission_type) { |
| QuicTransmissionInfo* transmission_info = |
| unacked_packets_.GetMutableTransmissionInfo(packet_number); |
| // A previous RTO retransmission may cause connection close; packets without |
| // retransmittable frames can be marked for loss retransmissions. |
| QUIC_BUG_IF(transmission_type != LOSS_RETRANSMISSION && |
| transmission_type != RTO_RETRANSMISSION && |
| !unacked_packets_.HasRetransmittableFrames(*transmission_info)) |
| << "transmission_type: " << transmission_type; |
| // Handshake packets should never be sent as probing retransmissions. |
| DCHECK(!transmission_info->has_crypto_handshake || |
| transmission_type != PROBING_RETRANSMISSION); |
| |
| HandleRetransmission(transmission_type, transmission_info); |
| |
| // Update packet state according to transmission type. |
| transmission_info->state = |
| QuicUtils::RetransmissionTypeToPacketState(transmission_type); |
| } |
| |
| void QuicSentPacketManager::HandleRetransmission( |
| TransmissionType transmission_type, |
| QuicTransmissionInfo* transmission_info) { |
| if (ShouldForceRetransmission(transmission_type)) { |
| // TODO(fayang): Consider to make RTO and PROBING retransmission |
| // strategies be configurable by applications. Today, TLP, RTO and PROBING |
| // retransmissions are handled similarly, i.e., always retranmist the |
| // oldest outstanding data. This is not ideal in general because different |
| // applications may want different strategies. For example, some |
| // applications may want to use higher priority stream data for bandwidth |
| // probing, and some applications want to consider RTO is an indication of |
| // loss, etc. |
| unacked_packets_.RetransmitFrames(*transmission_info, transmission_type); |
| return; |
| } |
| |
| unacked_packets_.NotifyFramesLost(*transmission_info, transmission_type); |
| if (transmission_info->retransmittable_frames.empty()) { |
| return; |
| } |
| |
| if (transmission_type == LOSS_RETRANSMISSION) { |
| // Record the first packet sent after loss, which allows to wait 1 |
| // more RTT before giving up on this lost packet. |
| transmission_info->retransmission = |
| unacked_packets_.largest_sent_packet() + 1; |
| } else { |
| // Clear the recorded first packet sent after loss when version or |
| // encryption changes. |
| transmission_info->retransmission.Clear(); |
| } |
| } |
| |
| void QuicSentPacketManager::RecordOneSpuriousRetransmission( |
| const QuicTransmissionInfo& info) { |
| stats_->bytes_spuriously_retransmitted += info.bytes_sent; |
| ++stats_->packets_spuriously_retransmitted; |
| if (debug_delegate_ != nullptr) { |
| debug_delegate_->OnSpuriousPacketRetransmission(info.transmission_type, |
| info.bytes_sent); |
| } |
| } |
| |
| void QuicSentPacketManager::MarkPacketHandled(QuicPacketNumber packet_number, |
| QuicTransmissionInfo* info, |
| QuicTime ack_receive_time, |
| QuicTime::Delta ack_delay_time, |
| QuicTime receive_timestamp) { |
| // Try to aggregate acked stream frames if acked packet is not a |
| // retransmission. |
| if (info->transmission_type == NOT_RETRANSMISSION) { |
| unacked_packets_.MaybeAggregateAckedStreamFrame(*info, ack_delay_time, |
| receive_timestamp); |
| } else { |
| unacked_packets_.NotifyAggregatedStreamFrameAcked(ack_delay_time); |
| const bool new_data_acked = unacked_packets_.NotifyFramesAcked( |
| *info, ack_delay_time, receive_timestamp); |
| if (!new_data_acked && info->transmission_type != NOT_RETRANSMISSION) { |
| // Record as a spurious retransmission if this packet is a |
| // retransmission and no new data gets acked. |
| QUIC_DVLOG(1) << "Detect spurious retransmitted packet " << packet_number |
| << " transmission type: " << info->transmission_type; |
| RecordOneSpuriousRetransmission(*info); |
| } |
| } |
| if (info->state == LOST) { |
| // Record as a spurious loss as a packet previously declared lost gets |
| // acked. |
| const PacketNumberSpace packet_number_space = |
| unacked_packets_.GetPacketNumberSpace(info->encryption_level); |
| const QuicPacketNumber previous_largest_acked = |
| supports_multiple_packet_number_spaces() |
| ? unacked_packets_.GetLargestAckedOfPacketNumberSpace( |
| packet_number_space) |
| : unacked_packets_.largest_acked(); |
| QUIC_DVLOG(1) << "Packet " << packet_number |
| << " was detected lost spuriously, " |
| "previous_largest_acked: " |
| << previous_largest_acked; |
| loss_algorithm_->SpuriousLossDetected(unacked_packets_, rtt_stats_, |
| ack_receive_time, packet_number, |
| previous_largest_acked); |
| ++stats_->packet_spuriously_detected_lost; |
| } |
| |
| if (network_change_visitor_ != nullptr && |
| info->bytes_sent > largest_mtu_acked_) { |
| largest_mtu_acked_ = info->bytes_sent; |
| network_change_visitor_->OnPathMtuIncreased(largest_mtu_acked_); |
| } |
| unacked_packets_.RemoveFromInFlight(info); |
| unacked_packets_.RemoveRetransmittability(info); |
| info->state = ACKED; |
| } |
| |
| bool QuicSentPacketManager::OnPacketSent( |
| SerializedPacket* serialized_packet, |
| QuicTime sent_time, |
| TransmissionType transmission_type, |
| HasRetransmittableData has_retransmittable_data) { |
| QuicPacketNumber packet_number = serialized_packet->packet_number; |
| DCHECK_LE(FirstSendingPacketNumber(), packet_number); |
| DCHECK(!unacked_packets_.IsUnacked(packet_number)); |
| QUIC_BUG_IF(serialized_packet->encrypted_length == 0) |
| << "Cannot send empty packets."; |
| if (pending_timer_transmission_count_ > 0) { |
| --pending_timer_transmission_count_; |
| } |
| |
| bool in_flight = has_retransmittable_data == HAS_RETRANSMITTABLE_DATA; |
| if (using_pacing_) { |
| pacing_sender_.OnPacketSent( |
| sent_time, unacked_packets_.bytes_in_flight(), packet_number, |
| serialized_packet->encrypted_length, has_retransmittable_data); |
| } else { |
| send_algorithm_->OnPacketSent( |
| sent_time, unacked_packets_.bytes_in_flight(), packet_number, |
| serialized_packet->encrypted_length, has_retransmittable_data); |
| } |
| |
| if (serialized_packet->encryption_level == ENCRYPTION_FORWARD_SECURE) { |
| one_rtt_packet_sent_ = true; |
| } |
| |
| unacked_packets_.AddSentPacket(serialized_packet, transmission_type, |
| sent_time, in_flight); |
| // Reset the retransmission timer anytime a pending packet is sent. |
| return in_flight; |
| } |
| |
| QuicSentPacketManager::RetransmissionTimeoutMode |
| QuicSentPacketManager::OnRetransmissionTimeout() { |
| DCHECK(unacked_packets_.HasInFlightPackets() || |
| (handshake_mode_disabled_ && !handshake_finished_)); |
| DCHECK_EQ(0u, pending_timer_transmission_count_); |
| // Handshake retransmission, timer based loss detection, TLP, and RTO are |
| // implemented with a single alarm. The handshake alarm is set when the |
| // handshake has not completed, the loss alarm is set when the loss detection |
| // algorithm says to, and the TLP and RTO alarms are set after that. |
| // The TLP alarm is always set to run for under an RTO. |
| switch (GetRetransmissionMode()) { |
| case HANDSHAKE_MODE: |
| DCHECK(!handshake_mode_disabled_); |
| ++stats_->crypto_retransmit_count; |
| RetransmitCryptoPackets(); |
| return HANDSHAKE_MODE; |
| case LOSS_MODE: { |
| ++stats_->loss_timeout_count; |
| QuicByteCount prior_in_flight = unacked_packets_.bytes_in_flight(); |
| const QuicTime now = clock_->Now(); |
| InvokeLossDetection(now); |
| MaybeInvokeCongestionEvent(false, prior_in_flight, now); |
| return LOSS_MODE; |
| } |
| case TLP_MODE: |
| ++stats_->tlp_count; |
| ++consecutive_tlp_count_; |
| pending_timer_transmission_count_ = 1; |
| // TLPs prefer sending new data instead of retransmitting data, so |
| // give the connection a chance to write before completing the TLP. |
| return TLP_MODE; |
| case RTO_MODE: |
| ++stats_->rto_count; |
| RetransmitRtoPackets(); |
| return RTO_MODE; |
| case PTO_MODE: |
| QUIC_DVLOG(1) << ENDPOINT << "PTO mode"; |
| ++stats_->pto_count; |
| if (handshake_mode_disabled_ && !ShouldArmPtoForApplicationData()) { |
| ++stats_->crypto_retransmit_count; |
| } |
| ++consecutive_pto_count_; |
| pending_timer_transmission_count_ = max_probe_packets_per_pto_; |
| return PTO_MODE; |
| } |
| } |
| |
| void QuicSentPacketManager::RetransmitCryptoPackets() { |
| DCHECK_EQ(HANDSHAKE_MODE, GetRetransmissionMode()); |
| ++consecutive_crypto_retransmission_count_; |
| bool packet_retransmitted = false; |
| QuicPacketNumber packet_number = unacked_packets_.GetLeastUnacked(); |
| std::vector<QuicPacketNumber> crypto_retransmissions; |
| for (QuicUnackedPacketMap::const_iterator it = unacked_packets_.begin(); |
| it != unacked_packets_.end(); ++it, ++packet_number) { |
| // Only retransmit frames which are in flight, and therefore have been sent. |
| if (!it->in_flight || it->state != OUTSTANDING || |
| !it->has_crypto_handshake || |
| !unacked_packets_.HasRetransmittableFrames(*it)) { |
| continue; |
| } |
| packet_retransmitted = true; |
| crypto_retransmissions.push_back(packet_number); |
| ++pending_timer_transmission_count_; |
| } |
| DCHECK(packet_retransmitted) << "No crypto packets found to retransmit."; |
| for (QuicPacketNumber retransmission : crypto_retransmissions) { |
| MarkForRetransmission(retransmission, HANDSHAKE_RETRANSMISSION); |
| } |
| } |
| |
| bool QuicSentPacketManager::MaybeRetransmitTailLossProbe() { |
| DCHECK(!pto_enabled_); |
| if (pending_timer_transmission_count_ == 0) { |
| return false; |
| } |
| if (!MaybeRetransmitOldestPacket(TLP_RETRANSMISSION)) { |
| return false; |
| } |
| return true; |
| } |
| |
| bool QuicSentPacketManager::MaybeRetransmitOldestPacket(TransmissionType type) { |
| QuicPacketNumber packet_number = unacked_packets_.GetLeastUnacked(); |
| for (QuicUnackedPacketMap::const_iterator it = unacked_packets_.begin(); |
| it != unacked_packets_.end(); ++it, ++packet_number) { |
| // Only retransmit frames which are in flight, and therefore have been sent. |
| if (!it->in_flight || it->state != OUTSTANDING || |
| !unacked_packets_.HasRetransmittableFrames(*it)) { |
| continue; |
| } |
| MarkForRetransmission(packet_number, type); |
| return true; |
| } |
| QUIC_DVLOG(1) |
| << "No retransmittable packets, so RetransmitOldestPacket failed."; |
| return false; |
| } |
| |
| void QuicSentPacketManager::RetransmitRtoPackets() { |
| DCHECK(!pto_enabled_); |
| QUIC_BUG_IF(pending_timer_transmission_count_ > 0) |
| << "Retransmissions already queued:" << pending_timer_transmission_count_; |
| // Mark two packets for retransmission. |
| QuicPacketNumber packet_number = unacked_packets_.GetLeastUnacked(); |
| std::vector<QuicPacketNumber> retransmissions; |
| for (QuicUnackedPacketMap::const_iterator it = unacked_packets_.begin(); |
| it != unacked_packets_.end(); ++it, ++packet_number) { |
| if (it->state == OUTSTANDING && |
| unacked_packets_.HasRetransmittableFrames(*it) && |
| pending_timer_transmission_count_ < max_rto_packets_) { |
| DCHECK(it->in_flight); |
| retransmissions.push_back(packet_number); |
| ++pending_timer_transmission_count_; |
| } |
| } |
| if (pending_timer_transmission_count_ > 0) { |
| if (consecutive_rto_count_ == 0) { |
| first_rto_transmission_ = unacked_packets_.largest_sent_packet() + 1; |
| } |
| ++consecutive_rto_count_; |
| } |
| for (QuicPacketNumber retransmission : retransmissions) { |
| MarkForRetransmission(retransmission, RTO_RETRANSMISSION); |
| } |
| if (retransmissions.empty()) { |
| QUIC_BUG_IF(pending_timer_transmission_count_ != 0); |
| // No packets to be RTO retransmitted, raise up a credit to allow |
| // connection to send. |
| QUIC_CODE_COUNT(no_packets_to_be_rto_retransmitted); |
| pending_timer_transmission_count_ = 1; |
| } |
| } |
| |
| void QuicSentPacketManager::MaybeSendProbePackets() { |
| if (pending_timer_transmission_count_ == 0) { |
| return; |
| } |
| PacketNumberSpace packet_number_space; |
| if (supports_multiple_packet_number_spaces()) { |
| // Find out the packet number space to send probe packets. |
| if (!GetEarliestPacketSentTimeForPto(&packet_number_space) |
| .IsInitialized()) { |
| QUIC_BUG_IF(unacked_packets_.perspective() == Perspective::IS_SERVER) |
| << "earlist_sent_time not initialized when trying to send PTO " |
| "retransmissions"; |
| return; |
| } |
| } |
| QuicPacketNumber packet_number = unacked_packets_.GetLeastUnacked(); |
| std::vector<QuicPacketNumber> probing_packets; |
| for (QuicUnackedPacketMap::const_iterator it = unacked_packets_.begin(); |
| it != unacked_packets_.end(); ++it, ++packet_number) { |
| if (it->state == OUTSTANDING && |
| unacked_packets_.HasRetransmittableFrames(*it) && |
| (!supports_multiple_packet_number_spaces() || |
| unacked_packets_.GetPacketNumberSpace(it->encryption_level) == |
| packet_number_space)) { |
| DCHECK(it->in_flight); |
| probing_packets.push_back(packet_number); |
| if (probing_packets.size() == pending_timer_transmission_count_) { |
| break; |
| } |
| } |
| } |
| |
| for (QuicPacketNumber retransmission : probing_packets) { |
| QUIC_DVLOG(1) << ENDPOINT << "Marking " << retransmission |
| << " for probing retransmission"; |
| MarkForRetransmission(retransmission, PTO_RETRANSMISSION); |
| } |
| // It is possible that there is not enough outstanding data for probing. |
| } |
| |
| void QuicSentPacketManager::AdjustPendingTimerTransmissions() { |
| if (pending_timer_transmission_count_ < max_probe_packets_per_pto_) { |
| // There are packets sent already, clear credit. |
| pending_timer_transmission_count_ = 0; |
| return; |
| } |
| // No packet gets sent, leave 1 credit to allow data to be write eventually. |
| pending_timer_transmission_count_ = 1; |
| } |
| |
| void QuicSentPacketManager::EnableIetfPtoAndLossDetection() { |
| if (pto_enabled_) { |
| QUIC_RELOADABLE_FLAG_COUNT_N(quic_default_on_pto, 2, 2); |
| // Disable handshake mode. |
| handshake_mode_disabled_ = true; |
| return; |
| } |
| pto_enabled_ = true; |
| handshake_mode_disabled_ = true; |
| // Default to 1 packet per PTO and skip a packet number. Arm the 1st PTO with |
| // max of earliest in flight sent time + PTO delay and 1.5 * srtt from |
| // last in flight packet. |
| max_probe_packets_per_pto_ = 1; |
| skip_packet_number_for_pto_ = true; |
| first_pto_srtt_multiplier_ = 1.5; |
| } |
| |
| void QuicSentPacketManager::StartExponentialBackoffAfterNthPto( |
| size_t exponential_backoff_start_point) { |
| pto_exponential_backoff_start_point_ = exponential_backoff_start_point; |
| } |
| |
| QuicSentPacketManager::RetransmissionTimeoutMode |
| QuicSentPacketManager::GetRetransmissionMode() const { |
| DCHECK(unacked_packets_.HasInFlightPackets() || |
| (handshake_mode_disabled_ && !handshake_finished_)); |
| if (!handshake_mode_disabled_ && !handshake_finished_ && |
| unacked_packets_.HasPendingCryptoPackets()) { |
| return HANDSHAKE_MODE; |
| } |
| if (loss_algorithm_->GetLossTimeout() != QuicTime::Zero()) { |
| return LOSS_MODE; |
| } |
| if (pto_enabled_) { |
| return PTO_MODE; |
| } |
| if (consecutive_tlp_count_ < max_tail_loss_probes_) { |
| if (unacked_packets_.HasUnackedRetransmittableFrames()) { |
| return TLP_MODE; |
| } |
| } |
| return RTO_MODE; |
| } |
| |
| void QuicSentPacketManager::InvokeLossDetection(QuicTime time) { |
| if (!packets_acked_.empty()) { |
| DCHECK_LE(packets_acked_.front().packet_number, |
| packets_acked_.back().packet_number); |
| largest_newly_acked_ = packets_acked_.back().packet_number; |
| } |
| LossDetectionInterface::DetectionStats detection_stats = |
| loss_algorithm_->DetectLosses(unacked_packets_, time, rtt_stats_, |
| largest_newly_acked_, packets_acked_, |
| &packets_lost_); |
| |
| if (detection_stats.sent_packets_max_sequence_reordering > |
| stats_->sent_packets_max_sequence_reordering) { |
| stats_->sent_packets_max_sequence_reordering = |
| detection_stats.sent_packets_max_sequence_reordering; |
| } |
| |
| stats_->sent_packets_num_borderline_time_reorderings += |
| detection_stats.sent_packets_num_borderline_time_reorderings; |
| |
| for (const LostPacket& packet : packets_lost_) { |
| QuicTransmissionInfo* info = |
| unacked_packets_.GetMutableTransmissionInfo(packet.packet_number); |
| ++stats_->packets_lost; |
| if (time > info->sent_time) { |
| stats_->total_loss_detection_time = |
| stats_->total_loss_detection_time + (time - info->sent_time); |
| } |
| if (debug_delegate_ != nullptr) { |
| debug_delegate_->OnPacketLoss(packet.packet_number, |
| info->encryption_level, LOSS_RETRANSMISSION, |
| time); |
| } |
| unacked_packets_.RemoveFromInFlight(info); |
| |
| MarkForRetransmission(packet.packet_number, LOSS_RETRANSMISSION); |
| } |
| } |
| |
| bool QuicSentPacketManager::MaybeUpdateRTT(QuicPacketNumber largest_acked, |
| QuicTime::Delta ack_delay_time, |
| QuicTime ack_receive_time) { |
| // We rely on ack_delay_time to compute an RTT estimate, so we |
| // only update rtt when the largest observed gets acked. |
| if (!unacked_packets_.IsUnacked(largest_acked)) { |
| return false; |
| } |
| // We calculate the RTT based on the highest ACKed packet number, the lower |
| // packet numbers will include the ACK aggregation delay. |
| const QuicTransmissionInfo& transmission_info = |
| unacked_packets_.GetTransmissionInfo(largest_acked); |
| // Ensure the packet has a valid sent time. |
| if (transmission_info.sent_time == QuicTime::Zero()) { |
| QUIC_BUG << "Acked packet has zero sent time, largest_acked:" |
| << largest_acked; |
| return false; |
| } |
| if (transmission_info.sent_time > ack_receive_time) { |
| QUIC_CODE_COUNT(quic_receive_acked_before_sending); |
| } |
| |
| QuicTime::Delta send_delta = ack_receive_time - transmission_info.sent_time; |
| const bool min_rtt_available = !rtt_stats_.min_rtt().IsZero(); |
| rtt_stats_.UpdateRtt(send_delta, ack_delay_time, ack_receive_time); |
| |
| if (!min_rtt_available && !rtt_stats_.min_rtt().IsZero()) { |
| loss_algorithm_->OnMinRttAvailable(); |
| } |
| |
| return true; |
| } |
| |
| QuicTime::Delta QuicSentPacketManager::TimeUntilSend(QuicTime now) const { |
| // The TLP logic is entirely contained within QuicSentPacketManager, so the |
| // send algorithm does not need to be consulted. |
| if (pending_timer_transmission_count_ > 0) { |
| return QuicTime::Delta::Zero(); |
| } |
| |
| if (using_pacing_) { |
| return pacing_sender_.TimeUntilSend(now, |
| unacked_packets_.bytes_in_flight()); |
| } |
| |
| return send_algorithm_->CanSend(unacked_packets_.bytes_in_flight()) |
| ? QuicTime::Delta::Zero() |
| : QuicTime::Delta::Infinite(); |
| } |
| |
| const QuicTime QuicSentPacketManager::GetRetransmissionTime() const { |
| if (!unacked_packets_.HasInFlightPackets() && |
| (!handshake_mode_disabled_ || handshake_finished_ || |
| unacked_packets_.perspective() == Perspective::IS_SERVER)) { |
| // Do not set the timer if there is nothing in flight. However, to avoid |
| // handshake deadlock due to anti-amplification limit, client needs to set |
| // PTO timer when the handshake is not confirmed even there is nothing in |
| // flight. |
| return QuicTime::Zero(); |
| } |
| if (pending_timer_transmission_count_ > 0) { |
| // Do not set the timer if there is any credit left. |
| return QuicTime::Zero(); |
| } |
| PacketNumberSpace packet_number_space; |
| if (GetQuicReloadableFlag(quic_fix_server_pto_timeout) && |
| supports_multiple_packet_number_spaces() && |
| unacked_packets_.perspective() == Perspective::IS_SERVER && |
| !GetEarliestPacketSentTimeForPto(&packet_number_space).IsInitialized()) { |
| // Do not set the timer on the server side if the only in flight packets are |
| // half RTT data. |
| QUIC_RELOADABLE_FLAG_COUNT(quic_fix_server_pto_timeout); |
| return QuicTime::Zero(); |
| } |
| switch (GetRetransmissionMode()) { |
| case HANDSHAKE_MODE: |
| return unacked_packets_.GetLastCryptoPacketSentTime() + |
| GetCryptoRetransmissionDelay(); |
| case LOSS_MODE: |
| return loss_algorithm_->GetLossTimeout(); |
| case TLP_MODE: { |
| DCHECK(!pto_enabled_); |
| // TODO(ianswett): When CWND is available, it would be preferable to |
| // set the timer based on the earliest retransmittable packet. |
| // Base the updated timer on the send time of the last packet. |
| const QuicTime sent_time = |
| unacked_packets_.GetLastInFlightPacketSentTime(); |
| const QuicTime tlp_time = sent_time + GetTailLossProbeDelay(); |
| // Ensure the TLP timer never gets set to a time in the past. |
| return std::max(clock_->ApproximateNow(), tlp_time); |
| } |
| case RTO_MODE: { |
| DCHECK(!pto_enabled_); |
| // The RTO is based on the first outstanding packet. |
| const QuicTime sent_time = |
| unacked_packets_.GetLastInFlightPacketSentTime(); |
| QuicTime rto_time = sent_time + GetRetransmissionDelay(); |
| // Wait for TLP packets to be acked before an RTO fires. |
| QuicTime tlp_time = sent_time + GetTailLossProbeDelay(); |
| return std::max(tlp_time, rto_time); |
| } |
| case PTO_MODE: { |
| if (!supports_multiple_packet_number_spaces()) { |
| if (first_pto_srtt_multiplier_ > 0 && |
| unacked_packets_.HasInFlightPackets() && |
| consecutive_pto_count_ == 0) { |
| // Arm 1st PTO with earliest in flight sent time, and make sure at |
| // least first_pto_srtt_multiplier_ * RTT has been passed since last |
| // in flight packet. |
| return std::max( |
| clock_->ApproximateNow(), |
| std::max(unacked_packets_.GetFirstInFlightTransmissionInfo() |
| ->sent_time + |
| GetProbeTimeoutDelay(), |
| unacked_packets_.GetLastInFlightPacketSentTime() + |
| first_pto_srtt_multiplier_ * |
| rtt_stats_.SmoothedOrInitialRtt())); |
| } |
| // Ensure PTO never gets set to a time in the past. |
| return std::max(clock_->ApproximateNow(), |
| unacked_packets_.GetLastInFlightPacketSentTime() + |
| GetProbeTimeoutDelay()); |
| } |
| |
| PacketNumberSpace packet_number_space = NUM_PACKET_NUMBER_SPACES; |
| // earliest_right_edge is the earliest sent time of the last in flight |
| // packet of all packet number spaces. |
| QuicTime earliest_right_edge = |
| GetEarliestPacketSentTimeForPto(&packet_number_space); |
| if (!earliest_right_edge.IsInitialized()) { |
| // Arm PTO from now if there is no in flight packets. |
| earliest_right_edge = clock_->ApproximateNow(); |
| } |
| if (first_pto_srtt_multiplier_ > 0 && |
| packet_number_space == APPLICATION_DATA && |
| consecutive_pto_count_ == 0) { |
| const QuicTransmissionInfo* first_application_info = |
| unacked_packets_.GetFirstInFlightTransmissionInfoOfSpace( |
| APPLICATION_DATA); |
| if (first_application_info != nullptr) { |
| // Arm 1st PTO with earliest in flight sent time, and make sure at |
| // least first_pto_srtt_multiplier_ * RTT has been passed since last |
| // in flight packet. Only do this for application data. |
| return std::max( |
| clock_->ApproximateNow(), |
| std::max( |
| first_application_info->sent_time + GetProbeTimeoutDelay(), |
| earliest_right_edge + first_pto_srtt_multiplier_ * |
| rtt_stats_.SmoothedOrInitialRtt())); |
| } |
| } |
| return std::max(clock_->ApproximateNow(), |
| earliest_right_edge + GetProbeTimeoutDelay()); |
| } |
| } |
| DCHECK(false); |
| return QuicTime::Zero(); |
| } |
| |
| const QuicTime::Delta QuicSentPacketManager::GetPathDegradingDelay() const { |
| return GetNConsecutiveRetransmissionTimeoutDelay( |
| max_tail_loss_probes_ + kNumRetransmissionDelaysForPathDegradingDelay); |
| } |
| |
| const QuicTime::Delta QuicSentPacketManager::GetNetworkBlackholeDelay( |
| int8_t num_rtos_for_blackhole_detection) const { |
| return GetNConsecutiveRetransmissionTimeoutDelay( |
| max_tail_loss_probes_ + num_rtos_for_blackhole_detection); |
| } |
| |
| const QuicTime::Delta QuicSentPacketManager::GetCryptoRetransmissionDelay() |
| const { |
| // This is equivalent to the TailLossProbeDelay, but slightly more aggressive |
| // because crypto handshake messages don't incur a delayed ack time. |
| QuicTime::Delta srtt = rtt_stats_.SmoothedOrInitialRtt(); |
| int64_t delay_ms; |
| if (conservative_handshake_retransmits_) { |
| // Using the delayed ack time directly could cause conservative handshake |
| // retransmissions to actually be more aggressive than the default. |
| delay_ms = std::max(peer_max_ack_delay_.ToMilliseconds(), |
| static_cast<int64_t>(2 * srtt.ToMilliseconds())); |
| } else { |
| delay_ms = std::max(kMinHandshakeTimeoutMs, |
| static_cast<int64_t>(1.5 * srtt.ToMilliseconds())); |
| } |
| return QuicTime::Delta::FromMilliseconds( |
| delay_ms << consecutive_crypto_retransmission_count_); |
| } |
| |
| const QuicTime::Delta QuicSentPacketManager::GetTailLossProbeDelay() const { |
| QuicTime::Delta srtt = rtt_stats_.SmoothedOrInitialRtt(); |
| if (enable_half_rtt_tail_loss_probe_ && consecutive_tlp_count_ == 0u) { |
| if (unacked_packets().HasUnackedStreamData()) { |
| // Enable TLPR if there are pending data packets. |
| return std::max(min_tlp_timeout_, srtt * 0.5); |
| } |
| } |
| if (!unacked_packets_.HasMultipleInFlightPackets()) { |
| // This expression really should be using the delayed ack time, but in TCP |
| // MinRTO was traditionally set to 2x the delayed ack timer and this |
| // expression assumed QUIC did the same. |
| return std::max(2 * srtt, 1.5 * srtt + (min_rto_timeout_ * 0.5)); |
| } |
| return std::max(min_tlp_timeout_, 2 * srtt); |
| } |
| |
| const QuicTime::Delta QuicSentPacketManager::GetRetransmissionDelay() const { |
| QuicTime::Delta retransmission_delay = QuicTime::Delta::Zero(); |
| if (rtt_stats_.smoothed_rtt().IsZero()) { |
| // We are in the initial state, use default timeout values. |
| retransmission_delay = |
| QuicTime::Delta::FromMilliseconds(kDefaultRetransmissionTimeMs); |
| } else { |
| retransmission_delay = |
| rtt_stats_.smoothed_rtt() + 4 * rtt_stats_.mean_deviation(); |
| if (retransmission_delay < min_rto_timeout_) { |
| retransmission_delay = min_rto_timeout_; |
| } |
| } |
| |
| // Calculate exponential back off. |
| retransmission_delay = |
| retransmission_delay * |
| (1 << std::min<size_t>(consecutive_rto_count_, kMaxRetransmissions)); |
| |
| if (retransmission_delay.ToMilliseconds() > kMaxRetransmissionTimeMs) { |
| return QuicTime::Delta::FromMilliseconds(kMaxRetransmissionTimeMs); |
| } |
| return retransmission_delay; |
| } |
| |
| const QuicTime::Delta QuicSentPacketManager::GetProbeTimeoutDelay() const { |
| DCHECK(pto_enabled_); |
| if (rtt_stats_.smoothed_rtt().IsZero()) { |
| // Respect kMinHandshakeTimeoutMs to avoid a potential amplification attack. |
| QUIC_BUG_IF(rtt_stats_.initial_rtt().IsZero()); |
| return std::max(3 * rtt_stats_.initial_rtt(), |
| QuicTime::Delta::FromMilliseconds(kMinHandshakeTimeoutMs)) * |
| (1 << consecutive_pto_count_); |
| } |
| const QuicTime::Delta rtt_var = use_standard_deviation_for_pto_ |
| ? rtt_stats_.GetStandardOrMeanDeviation() |
| : rtt_stats_.mean_deviation(); |
| QuicTime::Delta pto_delay = |
| rtt_stats_.smoothed_rtt() + |
| std::max(pto_rttvar_multiplier_ * rtt_var, kAlarmGranularity) + |
| (ShouldAddMaxAckDelay() ? peer_max_ack_delay_ : QuicTime::Delta::Zero()); |
| pto_delay = |
| pto_delay * (1 << (consecutive_pto_count_ - |
| std::min(consecutive_pto_count_, |
| pto_exponential_backoff_start_point_))); |
| if (consecutive_pto_count_ < num_tlp_timeout_ptos_) { |
| // Make first n PTOs similar to TLPs. |
| if (pto_delay > 2 * rtt_stats_.smoothed_rtt()) { |
| QUIC_CODE_COUNT(quic_delayed_pto); |
| pto_delay = std::max(kAlarmGranularity, 2 * rtt_stats_.smoothed_rtt()); |
| } else { |
| QUIC_CODE_COUNT(quic_faster_pto); |
| } |
| } |
| return pto_delay; |
| } |
| |
| QuicTime::Delta QuicSentPacketManager::GetSlowStartDuration() const { |
| if (send_algorithm_->GetCongestionControlType() == kBBR || |
| send_algorithm_->GetCongestionControlType() == kBBRv2) { |
| return stats_->slowstart_duration.GetTotalElapsedTime( |
| clock_->ApproximateNow()); |
| } |
| return QuicTime::Delta::Infinite(); |
| } |
| |
| std::string QuicSentPacketManager::GetDebugState() const { |
| return send_algorithm_->GetDebugState(); |
| } |
| |
| void QuicSentPacketManager::SetSendAlgorithm( |
| CongestionControlType congestion_control_type) { |
| if (send_algorithm_ && |
| send_algorithm_->GetCongestionControlType() == congestion_control_type) { |
| return; |
| } |
| |
| SetSendAlgorithm(SendAlgorithmInterface::Create( |
| clock_, &rtt_stats_, &unacked_packets_, congestion_control_type, random_, |
| stats_, initial_congestion_window_, send_algorithm_.get())); |
| } |
| |
| void QuicSentPacketManager::SetSendAlgorithm( |
| SendAlgorithmInterface* send_algorithm) { |
| send_algorithm_.reset(send_algorithm); |
| pacing_sender_.set_sender(send_algorithm); |
| } |
| |
| void QuicSentPacketManager::OnConnectionMigration(AddressChangeType type) { |
| if (type == PORT_CHANGE || type == IPV4_SUBNET_CHANGE) { |
| // Rtt and cwnd do not need to be reset when the peer address change is |
| // considered to be caused by NATs. |
| return; |
| } |
| consecutive_rto_count_ = 0; |
| consecutive_tlp_count_ = 0; |
| consecutive_pto_count_ = 0; |
| rtt_stats_.OnConnectionMigration(); |
| send_algorithm_->OnConnectionMigration(); |
| } |
| |
| void QuicSentPacketManager::OnAckFrameStart(QuicPacketNumber largest_acked, |
| QuicTime::Delta ack_delay_time, |
| QuicTime ack_receive_time) { |
| DCHECK(packets_acked_.empty()); |
| DCHECK_LE(largest_acked, unacked_packets_.largest_sent_packet()); |
| if (ack_delay_time > peer_max_ack_delay()) { |
| ack_delay_time = peer_max_ack_delay(); |
| } |
| rtt_updated_ = |
| MaybeUpdateRTT(largest_acked, ack_delay_time, ack_receive_time); |
| last_ack_frame_.ack_delay_time = ack_delay_time; |
| acked_packets_iter_ = last_ack_frame_.packets.rbegin(); |
| } |
| |
| void QuicSentPacketManager::OnAckRange(QuicPacketNumber start, |
| QuicPacketNumber end) { |
| if (!last_ack_frame_.largest_acked.IsInitialized() || |
| end > last_ack_frame_.largest_acked + 1) { |
| // Largest acked increases. |
| unacked_packets_.IncreaseLargestAcked(end - 1); |
| last_ack_frame_.largest_acked = end - 1; |
| } |
| // Drop ack ranges which ack packets below least_unacked. |
| QuicPacketNumber least_unacked = unacked_packets_.GetLeastUnacked(); |
| if (least_unacked.IsInitialized() && end <= least_unacked) { |
| return; |
| } |
| start = std::max(start, least_unacked); |
| do { |
| QuicPacketNumber newly_acked_start = start; |
| if (acked_packets_iter_ != last_ack_frame_.packets.rend()) { |
| newly_acked_start = std::max(start, acked_packets_iter_->max()); |
| } |
| for (QuicPacketNumber acked = end - 1; acked >= newly_acked_start; |
| --acked) { |
| // Check if end is above the current range. If so add newly acked packets |
| // in descending order. |
| packets_acked_.push_back(AckedPacket(acked, 0, QuicTime::Zero())); |
| if (acked == FirstSendingPacketNumber()) { |
| break; |
| } |
| } |
| if (acked_packets_iter_ == last_ack_frame_.packets.rend() || |
| start > acked_packets_iter_->min()) { |
| // Finish adding all newly acked packets. |
| return; |
| } |
| end = std::min(end, acked_packets_iter_->min()); |
| ++acked_packets_iter_; |
| } while (start < end); |
| } |
| |
| void QuicSentPacketManager::OnAckTimestamp(QuicPacketNumber packet_number, |
| QuicTime timestamp) { |
| last_ack_frame_.received_packet_times.push_back({packet_number, timestamp}); |
| for (AckedPacket& packet : packets_acked_) { |
| if (packet.packet_number == packet_number) { |
| packet.receive_timestamp = timestamp; |
| return; |
| } |
| } |
| } |
| |
| AckResult QuicSentPacketManager::OnAckFrameEnd( |
| QuicTime ack_receive_time, |
| QuicPacketNumber ack_packet_number, |
| EncryptionLevel ack_decrypted_level) { |
| QuicByteCount prior_bytes_in_flight = unacked_packets_.bytes_in_flight(); |
| // Reverse packets_acked_ so that it is in ascending order. |
| std::reverse(packets_acked_.begin(), packets_acked_.end()); |
| for (AckedPacket& acked_packet : packets_acked_) { |
| QuicTransmissionInfo* info = |
| unacked_packets_.GetMutableTransmissionInfo(acked_packet.packet_number); |
| if (!QuicUtils::IsAckable(info->state)) { |
| if (info->state == ACKED) { |
| QUIC_BUG << "Trying to ack an already acked packet: " |
| << acked_packet.packet_number |
| << ", last_ack_frame_: " << last_ack_frame_ |
| << ", least_unacked: " << unacked_packets_.GetLeastUnacked() |
| << ", packets_acked_: " << packets_acked_; |
| } else { |
| QUIC_PEER_BUG << "Received " << ack_decrypted_level |
| << " ack for unackable packet: " |
| << acked_packet.packet_number << " with state: " |
| << QuicUtils::SentPacketStateToString(info->state); |
| if (supports_multiple_packet_number_spaces()) { |
| if (info->state == NEVER_SENT) { |
| return UNSENT_PACKETS_ACKED; |
| } |
| return UNACKABLE_PACKETS_ACKED; |
| } |
| } |
| continue; |
| } |
| QUIC_DVLOG(1) << ENDPOINT << "Got an " << ack_decrypted_level |
| << " ack for packet " << acked_packet.packet_number |
| << " , state: " |
| << QuicUtils::SentPacketStateToString(info->state); |
| const PacketNumberSpace packet_number_space = |
| unacked_packets_.GetPacketNumberSpace(info->encryption_level); |
| if (supports_multiple_packet_number_spaces() && |
| QuicUtils::GetPacketNumberSpace(ack_decrypted_level) != |
| packet_number_space) { |
| return PACKETS_ACKED_IN_WRONG_PACKET_NUMBER_SPACE; |
| } |
| last_ack_frame_.packets.Add(acked_packet.packet_number); |
| if (info->encryption_level == ENCRYPTION_FORWARD_SECURE) { |
| one_rtt_packet_acked_ = true; |
| } |
| largest_packet_peer_knows_is_acked_.UpdateMax(info->largest_acked); |
| if (supports_multiple_packet_number_spaces()) { |
| largest_packets_peer_knows_is_acked_[packet_number_space].UpdateMax( |
| info->largest_acked); |
| } |
| // If data is associated with the most recent transmission of this |
| // packet, then inform the caller. |
| if (info->in_flight) { |
| acked_packet.bytes_acked = info->bytes_sent; |
| } else { |
| // Unackable packets are skipped earlier. |
| largest_newly_acked_ = acked_packet.packet_number; |
| } |
| unacked_packets_.MaybeUpdateLargestAckedOfPacketNumberSpace( |
| packet_number_space, acked_packet.packet_number); |
| MarkPacketHandled(acked_packet.packet_number, info, ack_receive_time, |
| last_ack_frame_.ack_delay_time, |
| acked_packet.receive_timestamp); |
| } |
| const bool acked_new_packet = !packets_acked_.empty(); |
| PostProcessNewlyAckedPackets(ack_packet_number, ack_decrypted_level, |
| last_ack_frame_, ack_receive_time, rtt_updated_, |
| prior_bytes_in_flight); |
| |
| return acked_new_packet ? PACKETS_NEWLY_ACKED : NO_PACKETS_NEWLY_ACKED; |
| } |
| |
| void QuicSentPacketManager::SetDebugDelegate(DebugDelegate* debug_delegate) { |
| debug_delegate_ = debug_delegate; |
| } |
| |
| void QuicSentPacketManager::OnApplicationLimited() { |
| if (using_pacing_) { |
| pacing_sender_.OnApplicationLimited(); |
| } |
| send_algorithm_->OnApplicationLimited(unacked_packets_.bytes_in_flight()); |
| if (debug_delegate_ != nullptr) { |
| debug_delegate_->OnApplicationLimited(); |
| } |
| } |
| |
| NextReleaseTimeResult QuicSentPacketManager::GetNextReleaseTime() const { |
| if (!using_pacing_) { |
| return {QuicTime::Zero(), false}; |
| } |
| |
| return pacing_sender_.GetNextReleaseTime(); |
| } |
| |
| void QuicSentPacketManager::SetInitialRtt(QuicTime::Delta rtt) { |
| const QuicTime::Delta min_rtt = |
| QuicTime::Delta::FromMicroseconds(kMinInitialRoundTripTimeUs); |
| const QuicTime::Delta max_rtt = |
| QuicTime::Delta::FromMicroseconds(kMaxInitialRoundTripTimeUs); |
| rtt_stats_.set_initial_rtt(std::max(min_rtt, std::min(max_rtt, rtt))); |
| } |
| |
| void QuicSentPacketManager::EnableMultiplePacketNumberSpacesSupport() { |
| EnableIetfPtoAndLossDetection(); |
| unacked_packets_.EnableMultiplePacketNumberSpacesSupport(); |
| } |
| |
| QuicPacketNumber QuicSentPacketManager::GetLargestAckedPacket( |
| EncryptionLevel decrypted_packet_level) const { |
| DCHECK(supports_multiple_packet_number_spaces()); |
| return unacked_packets_.GetLargestAckedOfPacketNumberSpace( |
| QuicUtils::GetPacketNumberSpace(decrypted_packet_level)); |
| } |
| |
| QuicPacketNumber QuicSentPacketManager::GetLargestPacketPeerKnowsIsAcked( |
| EncryptionLevel decrypted_packet_level) const { |
| DCHECK(supports_multiple_packet_number_spaces()); |
| return largest_packets_peer_knows_is_acked_[QuicUtils::GetPacketNumberSpace( |
| decrypted_packet_level)]; |
| } |
| |
| QuicTime::Delta |
| QuicSentPacketManager::GetNConsecutiveRetransmissionTimeoutDelay( |
| int num_timeouts) const { |
| QuicTime::Delta total_delay = QuicTime::Delta::Zero(); |
| const QuicTime::Delta srtt = rtt_stats_.SmoothedOrInitialRtt(); |
| int num_tlps = |
| std::min(num_timeouts, static_cast<int>(max_tail_loss_probes_)); |
| num_timeouts -= num_tlps; |
| if (num_tlps > 0) { |
| if (enable_half_rtt_tail_loss_probe_ && |
| unacked_packets().HasUnackedStreamData()) { |
| total_delay = total_delay + std::max(min_tlp_timeout_, srtt * 0.5); |
| --num_tlps; |
| } |
| if (num_tlps > 0) { |
| const QuicTime::Delta tlp_delay = |
| std::max(2 * srtt, unacked_packets_.HasMultipleInFlightPackets() |
| ? min_tlp_timeout_ |
| : (1.5 * srtt + (min_rto_timeout_ * 0.5))); |
| total_delay = total_delay + num_tlps * tlp_delay; |
| } |
| } |
| if (num_timeouts == 0) { |
| return total_delay; |
| } |
| |
| const QuicTime::Delta retransmission_delay = |
| rtt_stats_.smoothed_rtt().IsZero() |
| ? QuicTime::Delta::FromMilliseconds(kDefaultRetransmissionTimeMs) |
| : std::max(srtt + 4 * rtt_stats_.mean_deviation(), min_rto_timeout_); |
| total_delay = total_delay + ((1 << num_timeouts) - 1) * retransmission_delay; |
| return total_delay; |
| } |
| |
| #undef ENDPOINT // undef for jumbo builds |
| } // namespace quic |
