src/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
   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 // Default maximum packet size used in Linux TCP implementations.
  25 const QuicByteCount kDefaultTCPMSS = 1460;
  26
  27 class RttStats;
  28
  29 namespace test {
  30 class TcpCubicSenderPeer;
  31 }  // namespace test
  32
  33 class NET_EXPORT_PRIVATE TcpCubicSender : public SendAlgorithmInterface {
  34  public:
  35   // Reno option and max_tcp_congestion_window are provided for testing.
  36   TcpCubicSender(const QuicClock* clock,
  37                  const RttStats* rtt_stats,
  38                  bool reno,
  39                  QuicTcpCongestionWindow max_tcp_congestion_window,
  40                  QuicConnectionStats* stats);
  41   virtual ~TcpCubicSender();
  42
  43   // Start implementation of SendAlgorithmInterface.
  44   virtual void SetFromConfig(const QuicConfig& config, bool is_server) OVERRIDE;
  45   virtual void OnIncomingQuicCongestionFeedbackFrame(
  46       const QuicCongestionFeedbackFrame& feedback,
  47       QuicTime feedback_receive_time) OVERRIDE;
  48   virtual void OnPacketAcked(QuicPacketSequenceNumber acked_sequence_number,
  49                              QuicByteCount acked_bytes) OVERRIDE;
  50   virtual void OnPacketLost(QuicPacketSequenceNumber largest_loss,
  51                             QuicTime ack_receive_time) OVERRIDE;
  52   virtual bool OnPacketSent(QuicTime sent_time,
  53                             QuicPacketSequenceNumber sequence_number,
  54                             QuicByteCount bytes,
  55                             TransmissionType transmission_type,
  56                             HasRetransmittableData is_retransmittable) OVERRIDE;
  57   virtual void OnRetransmissionTimeout(bool packets_retransmitted) OVERRIDE;
  58   virtual void OnPacketAbandoned(QuicPacketSequenceNumber sequence_number,
  59                                  QuicByteCount abandoned_bytes) OVERRIDE;
  60   virtual QuicTime::Delta TimeUntilSend(
  61       QuicTime now,
  62       TransmissionType transmission_type,
  63       HasRetransmittableData has_retransmittable_data,
  64       IsHandshake handshake) OVERRIDE;
  65   virtual QuicBandwidth BandwidthEstimate() const OVERRIDE;
  66   virtual void UpdateRtt(QuicTime::Delta rtt_sample) OVERRIDE;
  67   virtual QuicTime::Delta RetransmissionDelay() const OVERRIDE;
  68   virtual QuicByteCount GetCongestionWindow() const OVERRIDE;
  69   // End implementation of SendAlgorithmInterface.
  70
  71  private:
  72   friend class test::TcpCubicSenderPeer;
  73
  74   QuicByteCount AvailableSendWindow();
  75   QuicByteCount SendWindow();
  76   void MaybeIncreaseCwnd(QuicPacketSequenceNumber acked_sequence_number);
  77   bool IsCwndLimited() const;
  78   bool InRecovery() const;
  79
  80   HybridSlowStart hybrid_slow_start_;
  81   Cubic cubic_;
  82   const RttStats* rtt_stats_;
  83
  84   // Reno provided for testing.
  85   const bool reno_;
  86
  87   // ACK counter for the Reno implementation.
  88   int64 congestion_window_count_;
  89
  90   // Receiver side advertised window.
  91   QuicByteCount receive_window_;
  92
  93   // Bytes in flight, aka bytes on the wire.
  94   QuicByteCount bytes_in_flight_;
  95
  96   // Bytes sent and acked since the last loss event.  Used for PRR.
  97   QuicByteCount prr_out_;
  98   QuicByteCount prr_delivered_;
  99   size_t ack_count_since_loss_;
 100
 101   // The congestion window before the last loss event.
 102   QuicByteCount bytes_in_flight_before_loss_;
 103
 104   // We need to keep track of the end sequence number of each RTT "burst".
 105   bool update_end_sequence_number_;
 106   QuicPacketSequenceNumber end_sequence_number_;
 107
 108   // Track the largest packet that has been sent.
 109   QuicPacketSequenceNumber largest_sent_sequence_number_;
 110
 111   // Track the largest packet that has been acked.
 112   QuicPacketSequenceNumber largest_acked_sequence_number_;
 113
 114   // Track the largest sequence number outstanding when a CWND cutback occurs.
 115   QuicPacketSequenceNumber largest_sent_at_last_cutback_;
 116
 117   // Congestion window in packets.
 118   QuicTcpCongestionWindow congestion_window_;
 119
 120   // Slow start congestion window in packets, aka ssthresh.
 121   QuicTcpCongestionWindow slowstart_threshold_;
 122
 123   // Maximum number of outstanding packets for tcp.
 124   QuicTcpCongestionWindow max_tcp_congestion_window_;
 125
 126   DISALLOW_COPY_AND_ASSIGN(TcpCubicSender);
 127 };
 128
 129 }  // namespace net
 130
 131 #endif  // NET_QUIC_CONGESTION_CONTROL_TCP_CUBIC_SENDER_H_