net/quic/congestion_control/tcp_cubic_sender.h

   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 TCP cubic.
   6
   7 #ifndef NET_QUIC_CONGESTION_CONTROL_TCP_CUBIC_SENDER_H_
   8 #define NET_QUIC_CONGESTION_CONTROL_TCP_CUBIC_SENDER_H_
   9
  10 #include "base/basictypes.h"
  11 #include "base/compiler_specific.h"
  12 #include "net/base/net_export.h"
  13 #include "net/quic/congestion_control/cubic.h"
  14 #include "net/quic/congestion_control/hybrid_slow_start.h"
  15 #include "net/quic/congestion_control/prr_sender.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                  QuicPacketCount initial_tcp_congestion_window,
  37                  QuicPacketCount max_tcp_congestion_window,
  38                  QuicConnectionStats* stats);
  39   ~TcpCubicSender() override;
  40
  41   // Start implementation of SendAlgorithmInterface.
  42   void SetFromConfig(const QuicConfig& config,
  43                      Perspective perspective) override;
  44   bool ResumeConnectionState(
  45       const CachedNetworkParameters& cached_network_params,
  46       bool max_bandwidth_resumption) override;
  47   void SetNumEmulatedConnections(int num_connections) override;
  48   void SetMaxCongestionWindow(QuicByteCount max_congestion_window) override;
  49   void OnCongestionEvent(bool rtt_updated,
  50                          QuicByteCount bytes_in_flight,
  51                          const CongestionVector& acked_packets,
  52                          const CongestionVector& lost_packets) override;
  53   bool OnPacketSent(QuicTime sent_time,
  54                     QuicByteCount bytes_in_flight,
  55                     QuicPacketSequenceNumber sequence_number,
  56                     QuicByteCount bytes,
  57                     HasRetransmittableData is_retransmittable) override;
  58   void OnRetransmissionTimeout(bool packets_retransmitted) override;
  59   QuicTime::Delta TimeUntilSend(
  60       QuicTime now,
  61       QuicByteCount bytes_in_flight,
  62       HasRetransmittableData has_retransmittable_data) const override;
  63   QuicBandwidth PacingRate() const override;
  64   QuicBandwidth BandwidthEstimate() const override;
  65   bool HasReliableBandwidthEstimate() const override;
  66   QuicTime::Delta RetransmissionDelay() const override;
  67   QuicByteCount GetCongestionWindow() const override;
  68   bool InSlowStart() const override;
  69   bool InRecovery() const override;
  70   QuicByteCount GetSlowStartThreshold() const override;
  71   CongestionControlType GetCongestionControlType() const override;
  72   // End implementation of SendAlgorithmInterface.
  73
  74  private:
  75   friend class test::TcpCubicSenderPeer;
  76
  77   // Compute the TCP Reno beta based on the current number of connections.
  78   float RenoBeta() const;
  79
  80   // TODO(ianswett): Remove these and migrate to OnCongestionEvent.
  81   void OnPacketAcked(QuicPacketSequenceNumber acked_sequence_number,
  82                      QuicByteCount acked_bytes,
  83                      QuicByteCount bytes_in_flight);
  84   void OnPacketLost(QuicPacketSequenceNumber largest_loss,
  85                     QuicByteCount bytes_in_flight);
  86
  87   void MaybeIncreaseCwnd(QuicPacketSequenceNumber acked_sequence_number,
  88                          QuicByteCount bytes_in_flight);
  89   bool IsCwndLimited(QuicByteCount bytes_in_flight) const;
  90
  91   HybridSlowStart hybrid_slow_start_;
  92   Cubic cubic_;
  93   PrrSender prr_;
  94   const RttStats* rtt_stats_;
  95   QuicConnectionStats* stats_;
  96
  97   // If true, Reno congestion control is used instead of Cubic.
  98   const bool reno_;
  99
 100   // Number of connections to simulate.
 101   uint32 num_connections_;
 102
 103   // ACK counter for the Reno implementation.
 104   uint64 congestion_window_count_;
 105
 106   // Track the largest packet that has been sent.
 107   QuicPacketSequenceNumber largest_sent_sequence_number_;
 108
 109   // Track the largest packet that has been acked.
 110   QuicPacketSequenceNumber largest_acked_sequence_number_;
 111
 112   // Track the largest sequence number outstanding when a CWND cutback occurs.
 113   QuicPacketSequenceNumber largest_sent_at_last_cutback_;
 114
 115   // Congestion window in packets.
 116   QuicPacketCount congestion_window_;
 117
 118   // Minimum congestion window in packets.
 119   QuicPacketCount min_congestion_window_;
 120
 121   // Slow start congestion window in packets, aka ssthresh.
 122   QuicPacketCount 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   QuicPacketCount max_tcp_congestion_window_;
 130
 131   const QuicClock* clock_;
 132
 133   DISALLOW_COPY_AND_ASSIGN(TcpCubicSender);
 134 };
 135
 136 }  // namespace net
 137
 138 #endif  // NET_QUIC_CONGESTION_CONTROL_TCP_CUBIC_SENDER_H_