tcp-bbr.h

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/*
 * 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/data-rate.h"
#include "ns3/random-variable-stream.h"
#include "ns3/tcp-congestion-ops.h"
#include "ns3/traced-value.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();
 
    TcpBbr();
 
    TcpBbr(const TcpBbr& sock);
 
    enum BbrMode_t
    {
        BBR_STARTUP,   
        BBR_DRAIN,     
        BBR_PROBE_BW,  
        BBR_PROBE_RTT, 
    };
 
    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);
 
    std::string GetName() const override;
    bool HasCongControl() const override;
    void CongControl(Ptr<TcpSocketState> tcb,
                     const TcpRateOps::TcpRateConnection& rc,
                     const TcpRateOps::TcpRateSample& rs) override;
    void CongestionStateSet(Ptr<TcpSocketState> tcb,
                            const TcpSocketState::TcpCongState_t newState) override;
    void CwndEvent(Ptr<TcpSocketState> tcb, const TcpSocketState::TcpCAEvent_t event) override;
    uint32_t GetSsThresh(Ptr<const TcpSocketState> tcb, uint32_t bytesInFlight) override;
    Ptr<TcpCongestionOps> Fork() override;
 
  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