tcp-bbr.h

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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2018 NITK Surathkal
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation;
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Authors: Vivek Jain <jain.vivek.anand@gmail.com>
 *          Viyom Mittal <viyommittal@gmail.com>
 *          Mohit P. Tahiliani <tahiliani@nitk.edu.in>
 */

#ifndef TCPBBR_H
#define TCPBBR_H

#include "ns3/tcp-congestion-ops.h"
#include "ns3/traced-value.h"
#include "ns3/data-rate.h"
#include "ns3/random-variable-stream.h"
#include "ns3/windowed-filter.h"

class TcpBbrCheckGainValuesTest;

namespace ns3 {

class TcpBbr : public TcpCongestionOps
{
public:
  static const uint8_t GAIN_CYCLE_LENGTH = 8;

  const static double PACING_GAIN_CYCLE [];
  static TypeId GetTypeId (void);

  TcpBbr ();

  TcpBbr (const TcpBbr &sock);

  typedef enum
  {
    BBR_STARTUP,        
    BBR_DRAIN,          
    BBR_PROBE_BW,       
    BBR_PROBE_RTT,      
  } BbrMode_t;

  typedef WindowedFilter<DataRate,
                         MaxFilter<DataRate>,
                         uint32_t,
                         uint32_t>
  MaxBandwidthFilter_t; 

  static const char* const BbrModeName[BBR_PROBE_RTT + 1];

  virtual void SetStream (uint32_t stream);

  virtual std::string GetName () const;
  virtual bool HasCongControl () const;
  virtual void CongControl (Ptr<TcpSocketState> tcb,
                            const TcpRateOps::TcpRateConnection &rc,
                            const TcpRateOps::TcpRateSample &rs);
  virtual void CongestionStateSet (Ptr<TcpSocketState> tcb,
                                   const TcpSocketState::TcpCongState_t newState);
  virtual void CwndEvent (Ptr<TcpSocketState> tcb,
                          const TcpSocketState::TcpCAEvent_t event);
  virtual uint32_t GetSsThresh (Ptr<const TcpSocketState> tcb,
                                uint32_t bytesInFlight);
  virtual Ptr<TcpCongestionOps> Fork ();

protected:
  friend class TcpBbrCheckGainValuesTest;

  void AdvanceCyclePhase ();

  void CheckCyclePhase (Ptr<TcpSocketState> tcb, const TcpRateOps::TcpRateSample &rs);

  void CheckDrain (Ptr<TcpSocketState> tcb);

  void CheckFullPipe (const TcpRateOps::TcpRateSample &rs);

  void CheckProbeRTT (Ptr<TcpSocketState> tcb, const TcpRateOps::TcpRateSample &rs);

  void EnterDrain ();

  void EnterProbeBW ();

  void EnterProbeRTT ();

  void EnterStartup ();

  void ExitProbeRTT ();

  uint32_t GetBbrState ();

  double GetPacingGain ();

  double GetCwndGain ();

  void HandleProbeRTT (Ptr<TcpSocketState> tcb);

  void HandleRestartFromIdle (Ptr<TcpSocketState> tcb, const TcpRateOps::TcpRateSample &rs);

  uint32_t InFlight (Ptr<TcpSocketState> tcb, double gain);

  void InitFullPipe ();

  void InitPacingRate (Ptr<TcpSocketState> tcb);

  void InitRoundCounting ();

  bool IsNextCyclePhase (Ptr<TcpSocketState> tcb, const TcpRateOps::TcpRateSample &rs);

  void ModulateCwndForProbeRTT (Ptr<TcpSocketState> tcb);

  bool ModulateCwndForRecovery (Ptr<TcpSocketState> tcb, const TcpRateOps::TcpRateSample &rs);

  void RestoreCwnd (Ptr<TcpSocketState> tcb);

  void SaveCwnd (Ptr<const TcpSocketState> tcb);

  void SetCwnd (Ptr<TcpSocketState> tcb, const TcpRateOps::TcpRateSample &rs);

  void SetPacingRate (Ptr<TcpSocketState> tcb, double gain);

  void SetSendQuantum (Ptr<TcpSocketState> tcb);

  void UpdateBtlBw (Ptr<TcpSocketState> tcb, const TcpRateOps::TcpRateSample &rs);

  void UpdateControlParameters (Ptr<TcpSocketState> tcb, const TcpRateOps::TcpRateSample &rs);

  void UpdateModelAndState (Ptr<TcpSocketState> tcb, const TcpRateOps::TcpRateSample &rs);

  void UpdateRound (Ptr<TcpSocketState> tcb, const TcpRateOps::TcpRateSample &rs);

  void UpdateRTprop (Ptr<TcpSocketState> tcb);

  void UpdateTargetCwnd (Ptr<TcpSocketState> tcb);

  void SetBbrState (BbrMode_t state);

  uint32_t AckAggregationCwnd();

  void UpdateAckAggregation(Ptr<TcpSocketState> tcb, const TcpRateOps::TcpRateSample &rs);

private:
  BbrMode_t   m_state        {BbrMode_t::BBR_STARTUP};           
  MaxBandwidthFilter_t   m_maxBwFilter;                          
  uint32_t    m_bandwidthWindowLength       {0};                 
  double      m_pacingGain                  {0};                 
  double      m_cWndGain                    {0};                 
  double      m_highGain                    {0};                 
  bool        m_isPipeFilled                {false};             
  uint32_t    m_minPipeCwnd                 {0};                 
  uint32_t    m_roundCount                  {0};                 
  bool        m_roundStart                  {false};             
  uint32_t    m_nextRoundDelivered          {0};                 
  Time        m_probeRttDuration            {MilliSeconds (200)};
  Time        m_probeRtPropStamp            {Seconds (0)};       
  Time        m_probeRttDoneStamp           {Seconds (0)};       
  bool        m_probeRttRoundDone           {false};             
  bool        m_packetConservation          {false};             
  uint32_t    m_priorCwnd                   {0};                 
  bool        m_idleRestart                 {false};             
  uint32_t    m_targetCWnd                  {0};                 
  DataRate    m_fullBandwidth               {0};                 
  uint32_t    m_fullBandwidthCount          {0};                 
  Time        m_rtProp                      {Time::Max ()};      
  uint32_t    m_sendQuantum                 {0};                 
  Time        m_cycleStamp                  {Seconds (0)};       
  uint32_t    m_cycleIndex                  {0};                 
  bool        m_rtPropExpired               {false};             
  Time        m_rtPropFilterLen             {Seconds (10)};      
  Time        m_rtPropStamp                 {Seconds (0)};       
  bool        m_isInitialized               {false};             
  Ptr<UniformRandomVariable> m_uv           {nullptr};           
  uint64_t    m_delivered                   {0};                 
  uint32_t    m_appLimited                  {0};                 
  uint32_t    m_txItemDelivered             {0};                 
  uint32_t    m_extraAckedGain              {1};                 
  uint32_t    m_extraAcked [2]              {0, 0};              
  uint32_t    m_extraAckedWinRtt            {0};                 
  uint32_t    m_extraAckedWinRttLength      {5};                 
  uint32_t    m_ackEpochAckedResetThresh    {1 << 17};           
  uint32_t    m_extraAckedIdx               {0};                 
  Time        m_ackEpochTime                {Seconds(0)};        
  uint32_t    m_ackEpochAcked               {0};                 
  bool        m_hasSeenRtt                  {false};             
};

} // namespace ns3
#endif // TCPBBR_H