net/quic/congestion_control/tcp_cubic_bytes_sender.h

   1 // Copyright (c) 2015 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_BYTES_SENDER_H_
   8 #define NET_QUIC_CONGESTION_CONTROL_TCP_CUBIC_BYTES_SENDER_H_
   9
  10 #include "base/basictypes.h"
  11 #include "net/base/net_export.h"
  12 #include "net/quic/congestion_control/cubic_bytes.h"
  13 #include "net/quic/congestion_control/hybrid_slow_start.h"
  14 #include "net/quic/congestion_control/prr_sender.h"
  15 #include "net/quic/congestion_control/send_algorithm_interface.h"
  16 #include "net/quic/quic_bandwidth.h"
  17 #include "net/quic/quic_connection_stats.h"
  18 #include "net/quic/quic_protocol.h"
  19 #include "net/quic/quic_time.h"
  20
  21 namespace net {
  22
  23 class RttStats;
  24
  25 namespace test {
  26 class TcpCubicBytesSenderPeer;
  27 }  // namespace test
  28
  29 class NET_EXPORT_PRIVATE TcpCubicBytesSender : public SendAlgorithmInterface {
  30  public:
  31   TcpCubicBytesSender(const QuicClock* clock,
  32                       const RttStats* rtt_stats,
  33                       bool reno,
  34                       QuicPacketCount initial_tcp_congestion_window,
  35                       QuicPacketCount max_congestion_window,
  36                       QuicConnectionStats* stats);
  37   ~TcpCubicBytesSender() override;
  38
  39   // Start implementation of SendAlgorithmInterface.
  40   void SetFromConfig(const QuicConfig& config,
  41                      Perspective perspective) override;
  42   bool ResumeConnectionState(
  43       const CachedNetworkParameters& cached_network_params,
  44       bool max_bandwidth_resumption) override;
  45   void SetNumEmulatedConnections(int num_connections) override;
  46   void SetMaxCongestionWindow(QuicByteCount max_congestion_window) override;
  47   void OnCongestionEvent(bool rtt_updated,
  48                          QuicByteCount bytes_in_flight,
  49                          const CongestionVector& acked_packets,
  50                          const CongestionVector& lost_packets) override;
  51   bool OnPacketSent(QuicTime sent_time,
  52                     QuicByteCount bytes_in_flight,
  53                     QuicPacketSequenceNumber sequence_number,
  54                     QuicByteCount bytes,
  55                     HasRetransmittableData is_retransmittable) override;
  56   void OnRetransmissionTimeout(bool packets_retransmitted) override;
  57   QuicTime::Delta TimeUntilSend(
  58       QuicTime now,
  59       QuicByteCount bytes_in_flight,
  60       HasRetransmittableData has_retransmittable_data) const override;
  61   QuicBandwidth PacingRate() const override;
  62   QuicBandwidth BandwidthEstimate() const override;
  63   bool HasReliableBandwidthEstimate() const override;
  64   QuicTime::Delta RetransmissionDelay() const override;
  65   QuicByteCount GetCongestionWindow() const override;
  66   bool InSlowStart() const override;
  67   bool InRecovery() const override;
  68   QuicByteCount GetSlowStartThreshold() const override;
  69   CongestionControlType GetCongestionControlType() const override;
  70   // End implementation of SendAlgorithmInterface.
  71
  72  private:
  73   friend class test::TcpCubicBytesSenderPeer;
  74
  75   // Compute the TCP Reno beta based on the current number of connections.
  76   float RenoBeta() const;
  77
  78   // TODO(ianswett): Remove these and migrate to OnCongestionEvent.
  79   void OnPacketAcked(QuicPacketSequenceNumber acked_sequence_number,
  80                      QuicByteCount acked_bytes,
  81                      QuicByteCount bytes_in_flight);
  82   void OnPacketLost(QuicPacketSequenceNumber largest_loss,
  83                     QuicByteCount bytes_in_flight);
  84
  85   void MaybeIncreaseCwnd(QuicPacketSequenceNumber acked_sequence_number,
  86                          QuicByteCount acked_bytes,
  87                          QuicByteCount bytes_in_flight);
  88   bool IsCwndLimited(QuicByteCount bytes_in_flight) const;
  89
  90   HybridSlowStart hybrid_slow_start_;
  91   CubicBytes cubic_;
  92   PrrSender prr_;
  93   const RttStats* rtt_stats_;
  94   QuicConnectionStats* stats_;
  95
  96   // If true, Reno congestion control is used instead of Cubic.
  97   const bool reno_;
  98
  99   // Number of connections to simulate.
 100   uint32 num_connections_;
 101
 102   // ACK counter for the Reno implementation.
 103   uint64 num_acked_packets_;
 104
 105   // Track the largest packet that has been sent.
 106   QuicPacketSequenceNumber largest_sent_sequence_number_;
 107
 108   // Track the largest packet that has been acked.
 109   QuicPacketSequenceNumber largest_acked_sequence_number_;
 110
 111   // Track the largest sequence number outstanding when a CWND cutback occurs.
 112   QuicPacketSequenceNumber largest_sent_at_last_cutback_;
 113
 114   // Congestion window in bytes.
 115   QuicByteCount congestion_window_;
 116
 117   // Minimum congestion window in bytes.
 118   QuicByteCount min_congestion_window_;
 119
 120   // Maximum congestion window in bytes.
 121   QuicByteCount max_congestion_window_;
 122
 123   // Slow start congestion window in bytes, aka ssthresh.
 124   QuicByteCount slowstart_threshold_;
 125
 126   // Whether the last loss event caused us to exit slowstart. Used for stats
 127   // collection of slowstart_packets_lost.
 128   bool last_cutback_exited_slowstart_;
 129
 130   const QuicClock* clock_;
 131
 132   DISALLOW_COPY_AND_ASSIGN(TcpCubicBytesSender);
 133 };
 134
 135 }  // namespace net
 136
 137 #endif  // NET_QUIC_CONGESTION_CONTROL_TCP_CUBIC_BYTES_SENDER_H_