dcf-manager.h

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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2005,2006 INRIA
 *
 * 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
 *
 * Author: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>
 */

#ifndef DCF_MANAGER_H
#define DCF_MANAGER_H

#include "ns3/nstime.h"
#include "ns3/event-id.h"
#include <vector>

namespace ns3 {

class WifiPhy;
class WifiMac;
class MacLow;
class PhyListener;
class LowDcfListener;

class DcfState
{
public:
  DcfState ();

  virtual ~DcfState ();

  void SetAifsn (uint32_t aifsn);
  void SetCwMin (uint32_t minCw);
  void SetCwMax (uint32_t maxCw);
  uint32_t GetAifsn (void) const;
  uint32_t GetCwMin (void) const;
  uint32_t GetCwMax (void) const;
  void ResetCw (void);
  void UpdateFailedCw (void);
  void StartBackoffNow (uint32_t nSlots);
  uint32_t GetCw (void) const;
  bool IsAccessRequested (void) const;

private:
  friend class DcfManager;

  uint32_t GetBackoffSlots (void) const;
  Time GetBackoffStart (void) const;
  void UpdateBackoffSlotsNow (uint32_t nSlots, Time backoffUpdateBound);
  void NotifyAccessRequested (void);
  void NotifyAccessGranted (void);
  void NotifyCollision (void);
  void NotifyInternalCollision (void);
  void NotifyChannelSwitching (void);


  virtual void DoNotifyAccessGranted (void) = 0;
  virtual void DoNotifyInternalCollision (void) = 0;
  virtual void DoNotifyCollision (void) = 0;
  virtual void DoNotifyChannelSwitching () = 0;

  uint32_t m_aifsn;
  uint32_t m_backoffSlots;
  // the backoffStart variable is used to keep track of the
  // time at which a backoff was started or the time at which
  // the backoff counter was last updated.
  Time m_backoffStart;
  uint32_t m_cwMin;
  uint32_t m_cwMax;
  uint32_t m_cw;
  bool m_accessRequested;
};

class DcfManager
{
public:
  DcfManager ();
  ~DcfManager ();

  void SetupPhyListener (Ptr<WifiPhy> phy);
  void SetupLowListener (Ptr<MacLow> low);

  void SetSlot (Time slotTime);
  void SetSifs (Time sifs);

  void SetEifsNoDifs (Time eifsNoDifs);

  Time GetEifsNoDifs () const;

  void Add (DcfState *dcf);

  void RequestAccess (DcfState *state);

  void NotifyRxStartNow (Time duration);
  void NotifyRxEndOkNow (void);
  void NotifyRxEndErrorNow (void);
  void NotifyTxStartNow (Time duration);
  void NotifyMaybeCcaBusyStartNow (Time duration);
  void NotifySwitchingStartNow (Time duration);
  void NotifyNavResetNow (Time duration);
  void NotifyNavStartNow (Time duration);
  void NotifyAckTimeoutStartNow (Time duration);
  void NotifyAckTimeoutResetNow ();
  void NotifyCtsTimeoutStartNow (Time duration);
  void NotifyCtsTimeoutResetNow ();
private:
  void UpdateBackoff (void);
  Time MostRecent (Time a, Time b) const;
  Time MostRecent (Time a, Time b, Time c) const;
  Time MostRecent (Time a, Time b, Time c, Time d) const;
  Time MostRecent (Time a, Time b, Time c, Time d, Time e, Time f) const;
  Time MostRecent (Time a, Time b, Time c, Time d, Time e, Time f, Time g) const;
  Time GetAccessGrantStart (void) const;
  Time GetBackoffStartFor (DcfState *state);
  Time GetBackoffEndFor (DcfState *state);
  void DoRestartAccessTimeoutIfNeeded (void);
  void AccessTimeout (void);
  void DoGrantAccess (void);
  bool IsBusy (void) const;

  typedef std::vector<DcfState *> States;

  States m_states;
  Time m_lastAckTimeoutEnd;
  Time m_lastCtsTimeoutEnd;
  Time m_lastNavStart;
  Time m_lastNavDuration;
  Time m_lastRxStart;
  Time m_lastRxDuration;
  bool m_lastRxReceivedOk;
  Time m_lastRxEnd;
  Time m_lastTxStart;
  Time m_lastTxDuration;
  Time m_lastBusyStart;
  Time m_lastBusyDuration;
  Time m_lastSwitchingStart;
  Time m_lastSwitchingDuration;
  bool m_rxing;
  Time m_eifsNoDifs;
  EventId m_accessTimeout;
  uint32_t m_slotTimeUs;
  Time m_sifs;
  PhyListener* m_phyListener;
  LowDcfListener* m_lowListener;
};

} // namespace ns3

#endif /* DCF_MANAGER_H */