1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 // 5 // TCP cubic send side congestion algorithm, emulates the behavior of 6 // TCP cubic. 7 8 #ifndef NET_QUIC_CONGESTION_CONTROL_TCP_CUBIC_SENDER_H_ 9 #define NET_QUIC_CONGESTION_CONTROL_TCP_CUBIC_SENDER_H_ 10 11 #include "base/basictypes.h" 12 #include "base/compiler_specific.h" 13 #include "net/base/net_export.h" 14 #include "net/quic/congestion_control/cubic.h" 15 #include "net/quic/congestion_control/hybrid_slow_start.h" 16 #include "net/quic/congestion_control/send_algorithm_interface.h" 17 #include "net/quic/quic_bandwidth.h" 18 #include "net/quic/quic_connection_stats.h" 19 #include "net/quic/quic_protocol.h" 20 #include "net/quic/quic_time.h" 21 22 namespace net { 23 24 class RttStats; 25 26 namespace test { 27 class TcpCubicSenderPeer; 28 } // namespace test 29 30 class NET_EXPORT_PRIVATE TcpCubicSender : public SendAlgorithmInterface { 31 public: 32 // Reno option and max_tcp_congestion_window are provided for testing. 33 TcpCubicSender(const QuicClock* clock, 34 const RttStats* rtt_stats, 35 bool reno, 36 QuicTcpCongestionWindow max_tcp_congestion_window, 37 QuicConnectionStats* stats); 38 virtual ~TcpCubicSender(); 39 40 bool InSlowStart() const; 41 42 // Start implementation of SendAlgorithmInterface. 43 virtual void SetFromConfig(const QuicConfig& config, bool is_server) OVERRIDE; 44 virtual void OnIncomingQuicCongestionFeedbackFrame( 45 const QuicCongestionFeedbackFrame& feedback, 46 QuicTime feedback_receive_time) OVERRIDE; 47 virtual void OnCongestionEvent(bool rtt_updated, 48 QuicByteCount bytes_in_flight, 49 const CongestionMap& acked_packets, 50 const CongestionMap& lost_packets) OVERRIDE; 51 virtual bool OnPacketSent(QuicTime sent_time, 52 QuicByteCount bytes_in_flight, 53 QuicPacketSequenceNumber sequence_number, 54 QuicByteCount bytes, 55 HasRetransmittableData is_retransmittable) OVERRIDE; 56 virtual void OnRetransmissionTimeout(bool packets_retransmitted) OVERRIDE; 57 virtual QuicTime::Delta TimeUntilSend( 58 QuicTime now, 59 QuicByteCount bytes_in_flight, 60 HasRetransmittableData has_retransmittable_data) const OVERRIDE; 61 virtual QuicBandwidth BandwidthEstimate() const OVERRIDE; 62 virtual QuicTime::Delta RetransmissionDelay() const OVERRIDE; 63 virtual QuicByteCount GetCongestionWindow() const OVERRIDE; 64 // End implementation of SendAlgorithmInterface. 65 66 private: 67 friend class test::TcpCubicSenderPeer; 68 69 // TODO(ianswett): Remove these and migrate to OnCongestionEvent. 70 void OnPacketAcked(QuicPacketSequenceNumber acked_sequence_number, 71 QuicByteCount acked_bytes, 72 QuicByteCount bytes_in_flight); 73 void OnPacketLost(QuicPacketSequenceNumber largest_loss, 74 QuicByteCount bytes_in_flight); 75 76 QuicByteCount SendWindow() const; 77 void MaybeIncreaseCwnd(QuicPacketSequenceNumber acked_sequence_number, 78 QuicByteCount bytes_in_flight); 79 bool IsCwndLimited(QuicByteCount bytes_in_flight) const; 80 bool InRecovery() const; 81 // Methods for isolating PRR from the rest of TCP Cubic. 82 void PrrOnPacketLost(QuicByteCount bytes_in_flight); 83 void PrrOnPacketAcked(QuicByteCount acked_bytes); 84 QuicTime::Delta PrrTimeUntilSend(QuicByteCount bytes_in_flight) const; 85 86 87 HybridSlowStart hybrid_slow_start_; 88 Cubic cubic_; 89 const RttStats* rtt_stats_; 90 QuicConnectionStats* stats_; 91 92 // Reno provided for testing. 93 const bool reno_; 94 95 // ACK counter for the Reno implementation. 96 int64 congestion_window_count_; 97 98 // Receiver side advertised window. 99 QuicByteCount receive_window_; 100 101 // Bytes sent and acked since the last loss event. Used for PRR. 102 QuicByteCount prr_out_; 103 QuicByteCount prr_delivered_; 104 size_t ack_count_since_loss_; 105 106 // The congestion window before the last loss event. 107 QuicByteCount bytes_in_flight_before_loss_; 108 109 // Track the largest packet that has been sent. 110 QuicPacketSequenceNumber largest_sent_sequence_number_; 111 112 // Track the largest packet that has been acked. 113 QuicPacketSequenceNumber largest_acked_sequence_number_; 114 115 // Track the largest sequence number outstanding when a CWND cutback occurs. 116 QuicPacketSequenceNumber largest_sent_at_last_cutback_; 117 118 // Congestion window in packets. 119 QuicTcpCongestionWindow congestion_window_; 120 121 // Slow start congestion window in packets, aka ssthresh. 122 QuicTcpCongestionWindow slowstart_threshold_; 123 124 // Whether the last loss event caused us to exit slowstart. 125 // Used for stats collection of slowstart_packets_lost 126 bool last_cutback_exited_slowstart_; 127 128 // Maximum number of outstanding packets for tcp. 129 QuicTcpCongestionWindow max_tcp_congestion_window_; 130 131 DISALLOW_COPY_AND_ASSIGN(TcpCubicSender); 132 }; 133 134 } // namespace net 135 136 #endif // NET_QUIC_CONGESTION_CONTROL_TCP_CUBIC_SENDER_H_ 137