src/net/quic/congestion_control/pacing_sender.h

   1 // Copyright (c) 2013 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 // A send algorithm which adds pacing on top of an another send algorithm.
   6 // It uses the underlying sender's bandwidth estimate to determine the
   7 // pacing rate to be used.  It also takes into consideration the expected
   8 // resolution of the underlying alarm mechanism to ensure that alarms are
   9 // not set too aggressively, and to smooth out variations.
  10
  11 #ifndef NET_QUIC_CONGESTION_CONTROL_PACING_SENDER_H_
  12 #define NET_QUIC_CONGESTION_CONTROL_PACING_SENDER_H_
  13
  14 #include <map>
  15
  16 #include "base/basictypes.h"
  17 #include "base/memory/scoped_ptr.h"
  18 #include "net/quic/congestion_control/send_algorithm_interface.h"
  19 #include "net/quic/quic_bandwidth.h"
  20 #include "net/quic/quic_config.h"
  21 #include "net/quic/quic_protocol.h"
  22 #include "net/quic/quic_time.h"
  23
  24 namespace net {
  25
  26 class NET_EXPORT_PRIVATE PacingSender : public SendAlgorithmInterface {
  27  public:
  28   PacingSender(SendAlgorithmInterface* sender,
  29                QuicTime::Delta alarm_granularity);
  30   virtual ~PacingSender();
  31
  32   // SendAlgorithmInterface methods.
  33   virtual void SetFromConfig(const QuicConfig& config, bool is_server) OVERRIDE;
  34   virtual void OnIncomingQuicCongestionFeedbackFrame(
  35       const QuicCongestionFeedbackFrame& feedback,
  36       QuicTime feedback_receive_time) OVERRIDE;
  37   virtual void OnCongestionEvent(bool rtt_updated,
  38                                  QuicByteCount bytes_in_flight,
  39                                  const CongestionMap& acked_packets,
  40                                  const CongestionMap& lost_packets) OVERRIDE;
  41   virtual bool OnPacketSent(QuicTime sent_time,
  42                             QuicByteCount bytes_in_flight,
  43                             QuicPacketSequenceNumber sequence_number,
  44                             QuicByteCount bytes,
  45                             HasRetransmittableData is_retransmittable) OVERRIDE;
  46   virtual void OnRetransmissionTimeout(bool packets_retransmitted) OVERRIDE;
  47   virtual QuicTime::Delta TimeUntilSend(
  48       QuicTime now,
  49       QuicByteCount bytes_in_flight,
  50       HasRetransmittableData has_retransmittable_data) OVERRIDE;
  51   virtual QuicBandwidth BandwidthEstimate() const OVERRIDE;
  52   virtual QuicTime::Delta RetransmissionDelay() const OVERRIDE;
  53   virtual QuicByteCount GetCongestionWindow() const OVERRIDE;
  54
  55  private:
  56   scoped_ptr<SendAlgorithmInterface> sender_;  // Underlying sender.
  57   QuicTime::Delta alarm_granularity_;
  58   QuicTime next_packet_send_time_;  // When can the next packet be sent.
  59   bool was_last_send_delayed_;  // True when the last send was delayed.
  60   bool has_valid_rtt_;  // True if we have at least one RTT update.
  61
  62   DISALLOW_COPY_AND_ASSIGN(PacingSender);
  63 };
  64
  65 }  // namespace net
  66
  67 #endif  // NET_QUIC_CONGESTION_CONTROL_PACING_SENDER_H_