pie-queue-disc.h

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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2016 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: Shravya Ks <shravya.ks0@gmail.com>
 *          Smriti Murali <m.smriti.95@gmail.com>
 *          Mohit P. Tahiliani <tahiliani@nitk.edu.in>
 */

/*
 * PORT NOTE: This code was ported from ns-2.36rc1 (queue/pie.h).
 * Most of the comments are also ported from the same.
 */

#ifndef PIE_QUEUE_DISC_H
#define PIE_QUEUE_DISC_H

#include "ns3/queue-disc.h"
#include "ns3/nstime.h"
#include "ns3/boolean.h"
#include "ns3/data-rate.h"
#include "ns3/timer.h"
#include "ns3/event-id.h"
#include "ns3/random-variable-stream.h"

#define BURST_RESET_TIMEOUT 1.5

namespace ns3 {

class TraceContainer;
class UniformRandomVariable;

class PieQueueDisc : public QueueDisc
{
public:
  static TypeId GetTypeId (void);

  PieQueueDisc ();

  virtual ~PieQueueDisc ();

  enum BurstStateT
  {
    NO_BURST,
    IN_BURST,
    IN_BURST_PROTECTING,
  };

  enum QueueDiscMode
  {
    QUEUE_DISC_MODE_PACKETS,     
    QUEUE_DISC_MODE_BYTES,       
  };

  void SetMode (QueueDiscMode mode);

  QueueDiscMode GetMode (void) const;

  uint32_t GetQueueSize (void);

  void SetQueueLimit (uint32_t lim);

  Time GetQueueDelay (void);

  int64_t AssignStreams (int64_t stream);

  // Reasons for dropping packets
  static constexpr const char* UNFORCED_DROP = "Unforced drop";  
  static constexpr const char* FORCED_DROP = "Forced drop";      

protected:
  virtual void DoDispose (void);

private:
  virtual bool DoEnqueue (Ptr<QueueDiscItem> item);
  virtual Ptr<QueueDiscItem> DoDequeue (void);
  virtual Ptr<const QueueDiscItem> DoPeek (void);
  virtual bool CheckConfig (void);

  virtual void InitializeParams (void);

  bool DropEarly (Ptr<QueueDiscItem> item, uint32_t qSize);

  void CalculateP ();

  static const uint64_t DQCOUNT_INVALID = std::numeric_limits<uint64_t>::max();  

  // ** Variables supplied by user
  Time m_sUpdate;                               
  Time m_tUpdate;                               
  Time m_qDelayRef;                             
  uint32_t m_meanPktSize;                       
  Time m_maxBurst;                              
  double m_a;                                   
  double m_b;                                   
  uint32_t m_dqThreshold;                       

  // ** Variables maintained by PIE
  double m_dropProb;                            
  Time m_qDelayOld;                             
  Time m_qDelay;                                
  Time m_burstAllowance;                        
  uint32_t m_burstReset;                        
  BurstStateT m_burstState;                     
  bool m_inMeasurement;                         
  double m_avgDqRate;                           
  double m_dqStart;                             
  uint64_t m_dqCount;                           
  EventId m_rtrsEvent;                          
  Ptr<UniformRandomVariable> m_uv;              
};

};   // namespace ns3

#endif