tcp-socket-state.h

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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2018 Natale Patriciello <natale.patriciello@gmail.com>
 *
 * 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
 */
#ifndef TCP_SOCKET_STATE_H
#define TCP_SOCKET_STATE_H

#include "ns3/object.h"
#include "ns3/data-rate.h"
#include "ns3/traced-value.h"
#include "ns3/sequence-number.h"
#include "tcp-rx-buffer.h"

namespace ns3 {

class TcpSocketState : public Object
{
public:
  static TypeId GetTypeId (void);

  TcpSocketState () : Object () { }

  TcpSocketState (const TcpSocketState &other);

  typedef enum
  {
    CA_OPEN,      
    CA_DISORDER,  
    CA_CWR,       
    CA_RECOVERY,  
    CA_LOSS,      
    CA_LAST_STATE 
  } TcpCongState_t;

  // Note: "not triggered" events are currently not triggered by the code.
  typedef enum
  {
    CA_EVENT_TX_START,     
    CA_EVENT_CWND_RESTART, 
    CA_EVENT_COMPLETE_CWR, 
    CA_EVENT_LOSS,         
    CA_EVENT_ECN_NO_CE,    
    CA_EVENT_ECN_IS_CE,    
    CA_EVENT_DELAYED_ACK,  
    CA_EVENT_NON_DELAYED_ACK, 
  } TcpCAEvent_t;

  typedef enum
    {
      Off        = 0,   
      On         = 1,   
      AcceptOnly = 2,   
    } UseEcn_t;

  typedef enum
    {
      NotECT   = 0,   
      Ect1     = 1,   
      Ect0     = 2,   
      CongExp  = 3,   
    } EcnCodePoint_t;

  typedef enum
    {
      ClassicEcn,  
      DctcpEcn,    
    } EcnMode_t;

  typedef enum
  {
    ECN_DISABLED = 0, 
    ECN_IDLE,         
    ECN_CE_RCVD,      
    ECN_SENDING_ECE,  
    ECN_ECE_RCVD,     
    ECN_CWR_SENT      
  } EcnState_t;

  static const char* const TcpCongStateName[TcpSocketState::CA_LAST_STATE];

  static const char* const EcnStateName[TcpSocketState::ECN_CWR_SENT + 1];

  // Congestion control
  TracedValue<uint32_t>  m_cWnd             {0}; 
  TracedValue<uint32_t>  m_cWndInfl         {0}; 
  TracedValue<uint32_t>  m_ssThresh         {0}; 
  uint32_t               m_initialCWnd      {0}; 
  uint32_t               m_initialSsThresh  {0}; 

  // Recovery
  // This variable is used for implementing following flag of Linux: FLAG_RETRANS_DATA_ACKED
  // and is used only during a recovery phase to keep track of acknowledgement of retransmitted packet.
  bool                   m_isRetransDataAcked  {false}; 

  // Segment
  uint32_t               m_segmentSize   {0}; 
  SequenceNumber32       m_lastAckedSeq  {0}; 

  TracedValue<TcpCongState_t> m_congState {CA_OPEN}; 

  TracedValue<EcnState_t> m_ecnState {ECN_DISABLED}; 

  TracedValue<SequenceNumber32> m_highTxMark     {0}; 
  TracedValue<SequenceNumber32> m_nextTxSequence {0}; 

  uint32_t               m_rcvTimestampValue     {0}; 
  uint32_t               m_rcvTimestampEchoReply {0}; 

  // Pacing related variables
  bool                   m_pacing            {false}; 
  DataRate               m_maxPacingRate     {0};    
  TracedValue<DataRate>  m_pacingRate {0};           
  uint16_t               m_pacingSsRatio {0};        
  uint16_t               m_pacingCaRatio {0};        
  bool                   m_paceInitialWindow {false}; 

  Time                   m_minRtt  {Time::Max ()};   

  TracedValue<uint32_t>  m_bytesInFlight {0};        
  TracedValue<Time>      m_lastRtt {Seconds (0.0)};  

  Ptr<TcpRxBuffer>       m_rxBuffer;                 

  EcnMode_t              m_ecnMode {ClassicEcn}; 
  UseEcn_t               m_useEcn {Off};         

  EcnCodePoint_t         m_ectCodePoint {Ect0};  

  uint32_t GetCwndInSegments () const
  {
    return m_cWnd / m_segmentSize;
  }

  uint32_t GetSsThreshInSegments () const
  {
    return m_ssThresh / m_segmentSize;
  }

  Callback <void, uint8_t> m_sendEmptyPacketCallback;
};

namespace TracedValueCallback {

  typedef void (* TcpCongState)(const TcpSocketState::TcpCongState_t oldValue,
                                const TcpSocketState::TcpCongState_t newValue);

  typedef void (* EcnState)(const TcpSocketState::EcnState_t oldValue,
                            const TcpSocketState::EcnState_t newValue);

}  // namespace TracedValueCallback

} //namespace ns3

#endif /* TCP_SOCKET_STATE_H */