tcp-tx-buffer.h

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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2010-2015 Adrian Sai-wah Tam
 * Copyright (c) 2016 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
 *
 * Original author: Adrian Sai-wah Tam <adrian.sw.tam@gmail.com>
 */

#ifndef TCP_TX_BUFFER_H
#define TCP_TX_BUFFER_H

#include "ns3/object.h"
#include "ns3/traced-value.h"
#include "ns3/sequence-number.h"
#include "ns3/nstime.h"
#include "ns3/tcp-option-sack.h"
#include "ns3/packet.h"

namespace ns3 {
class Packet;

class TcpTxItem
{
public:
  // Default constructor, copy-constructor, destructor

  void Print (std::ostream &os) const;

  uint32_t GetSeqSize (void) const { return m_packet && m_packet->GetSize () > 0 ? m_packet->GetSize () : 1; }

  SequenceNumber32 m_startSeq {0};     
  Ptr<Packet> m_packet {nullptr};    
  bool m_lost          {false};      
  bool m_retrans       {false};      
  Time m_lastSent      {Time::Min()};
  bool m_sacked        {false};      
};

class TcpTxBuffer : public Object
{
public:
  static TypeId GetTypeId (void);
  TcpTxBuffer (uint32_t n = 0);
  virtual ~TcpTxBuffer (void);

  // Accessors

  SequenceNumber32 HeadSequence (void) const;

  SequenceNumber32 TailSequence (void) const;

  uint32_t Size (void) const;

  uint32_t MaxBufferSize (void) const;

  void SetMaxBufferSize (uint32_t n);

  uint32_t Available (void) const;

  void SetDupAckThresh (uint32_t dupAckThresh) { m_dupAckThresh = dupAckThresh; }

  void SetSegmentSize (uint32_t segmentSize) { m_segmentSize = segmentSize; }

  uint32_t GetRetransmitsCount (void) const { return m_retrans; }

  uint32_t GetLost (void) const { return m_lostOut; }

  uint32_t GetSacked (void) const { return m_sackedOut; }

  bool Add (Ptr<Packet> p);

  uint32_t SizeFromSequence (const SequenceNumber32& seq) const;

  Ptr<Packet> CopyFromSequence (uint32_t numBytes, const SequenceNumber32& seq);

  void SetHeadSequence (const SequenceNumber32& seq);

  void DiscardUpTo (const SequenceNumber32& seq);

  bool Update (const TcpOptionSack::SackList &list);

  bool IsLost (const SequenceNumber32 &seq) const;

  bool NextSeg (SequenceNumber32 *seq, bool isRecovery) const;

  uint32_t BytesInFlight () const;

  void SetSentListLost (bool resetSack = false);

  bool IsHeadRetransmitted () const;

  void DeleteRetransmittedFlagFromHead ();

  void ResetSentList ();

  void ResetLastSegmentSent ();

  void MarkHeadAsLost ();

  void AddRenoSack ();

  void ResetRenoSack ();

private:
  friend std::ostream & operator<< (std::ostream & os, TcpTxBuffer const & tcpTxBuf);

  typedef std::list<TcpTxItem*> PacketList; 

  void UpdateLostCount ();

  void RemoveFromCounts (TcpTxItem *item, uint32_t size);

  bool IsLostRFC (const SequenceNumber32 &seq, const PacketList::const_iterator &segment) const;

  uint32_t BytesInFlightRFC () const;

  TcpTxItem* GetNewSegment (uint32_t numBytes);

  TcpTxItem* GetTransmittedSegment (uint32_t numBytes, const SequenceNumber32 &seq);

  TcpTxItem* GetPacketFromList (PacketList &list, const SequenceNumber32 &startingSeq,
                                uint32_t numBytes, const SequenceNumber32 &requestedSeq,
                                bool *listEdited = nullptr) const;

  void MergeItems (TcpTxItem *t1, TcpTxItem *t2) const;

  void SplitItems (TcpTxItem *t1, TcpTxItem *t2, uint32_t size) const;

  void ConsistencyCheck () const;

  std::pair <TcpTxBuffer::PacketList::const_iterator, SequenceNumber32>
  FindHighestSacked () const;

  PacketList m_appList;  
  PacketList m_sentList; 
  uint32_t m_maxBuffer;  
  uint32_t m_size;       
  uint32_t m_sentSize;   

  TracedValue<SequenceNumber32> m_firstByteSeq; 
  std::pair <PacketList::const_iterator, SequenceNumber32> m_highestSack; 

  uint32_t m_lostOut   {0}; 
  uint32_t m_sackedOut {0}; 
  uint32_t m_retrans   {0}; 

  uint32_t m_dupAckThresh {0}; 
  uint32_t m_segmentSize {0}; 
  bool     m_renoSack {false}; 

};

std::ostream & operator<< (std::ostream & os, TcpTxBuffer const & tcpTxBuf);

std::ostream & operator<< (std::ostream & os, TcpTxItem const & item);

} // namespace ns3

#endif /* TCP_TX_BUFFER_H */