tcp-westwood.h

/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2013 ResiliNets, ITTC, University of Kansas 
 *
 * 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: Siddharth Gangadhar <siddharth@ittc.ku.edu>, Truc Anh N. Nguyen <annguyen@ittc.ku.edu>,
 * and Greeshma Umapathi
 *
 * James P.G. Sterbenz <jpgs@ittc.ku.edu>, director
 * ResiliNets Research Group  http://wiki.ittc.ku.edu/resilinets
 * Information and Telecommunication Technology Center (ITTC)
 * and Department of Electrical Engineering and Computer Science
 * The University of Kansas Lawrence, KS USA.
 *
 * Work supported in part by NSF FIND (Future Internet Design) Program
 * under grant CNS-0626918 (Postmodern Internet Architecture),
 * NSF grant CNS-1050226 (Multilayer Network Resilience Analysis and Experimentation on GENI),
 * US Department of Defense (DoD), and ITTC at The University of Kansas.
 */

#ifndef TCP_WESTWOOD_H
#define TCP_WESTWOOD_H

#include "tcp-socket-base.h"
#include "ns3/packet.h"

namespace ns3 {

class TcpWestwood : public TcpSocketBase
{
public:
  static TypeId GetTypeId (void);

  TcpWestwood (void);
  TcpWestwood (const TcpWestwood& sock);
  virtual ~TcpWestwood (void);

  enum ProtocolType 
  {
    WESTWOOD,
    WESTWOODPLUS
  };

  enum FilterType 
  {
    NONE,
    TUSTIN
  };

  // From TcpSocketBase
  virtual int Connect (const Address &address);
  virtual int Listen (void);

protected:
  virtual uint32_t Window (void);

  virtual Ptr<TcpSocketBase> Fork (void);

  virtual void ReceivedAck (Ptr<Packet> packet, const TcpHeader& tcpHeader);
  
  virtual void NewAck (SequenceNumber32 const& seq);

  virtual void DupAck (const TcpHeader& header, uint32_t count);

  virtual void Retransmit (void);

  virtual void EstimateRtt (const TcpHeader& header);

  // Implementing ns3::TcpSocket -- Attribute get/set
  virtual void SetSegSize (uint32_t size);

  virtual void SetSSThresh (uint32_t threshold);

  virtual uint32_t GetSSThresh (void) const;

  virtual void SetInitialCwnd (uint32_t cwnd);

  virtual uint32_t GetInitialCwnd (void) const;

private:
  void InitializeCwnd (void);

  int CountAck (const TcpHeader& tcpHeader);

  void UpdateAckedSegments (int acked);

  void EstimateBW (int acked, const TcpHeader& tcpHeader, Time rtt);

  void Filtering (void);

protected:
  TracedValue<uint32_t>  m_cWnd;                   //< Congestion window
  uint32_t               m_ssThresh;               //< Slow Start Threshold
  uint32_t               m_initialCWnd;            //< Initial cWnd value
  bool                   m_inFastRec;              //< Currently in fast recovery if TRUE

  TracedValue<double>    m_currentBW;              //< Current value of the estimated BW
  double                 m_lastSampleBW;           //< Last bandwidth sample
  double                 m_lastBW;                 //< Last bandwidth sample after being filtered
  Time                   m_minRtt;                 //< Minimum RTT
  double                 m_lastAck;                //< The time last ACK was received
  SequenceNumber32       m_prevAckNo;              //< Previously received ACK number
  int                    m_accountedFor;           //< The number of received DUPACKs
  enum ProtocolType      m_pType;                  //< 0 for Westwood, 1 for Westwood+
  enum FilterType        m_fType;                  //< 0 for none, 1 for Tustin

  int                    m_ackedSegments;          //< The number of segments ACKed between RTTs
  bool                   m_IsCount;                //< Start keeping track of m_ackedSegments for Westwood+ if TRUE
  EventId                m_bwEstimateEvent;        //< The BW estimation event for Westwood+

};

} // namespace ns3

#endif /* TCP_WESTWOOD_H */