text: /* -*-	Mode:C++; c-basic-offset:8; tab-width:8; indent-tabs-mode:t -*- */
  /*
   * Copyright (c) 1990-1997 Regents of the University of California.
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. All advertising materials mentioning features or use of this software
   *    must display the following acknowledgement:
   *	This product includes software developed by the Computer Systems
   *	Engineering Group at Lawrence Berkeley Laboratory.
   * 4. Neither the name of the University nor of the Laboratory may be used
   *    to endorse or promote products derived from this software without
   *    specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   *
   */
  
  
  /*
   * Based on PI controller described in:
   * C. Hollot, V. Misra, D. Towsley and W. Gong. 
   * On Designing Improved Controllers for AQM Routers
   * Supporting TCP Flows, 
   * INFOCOMM 2001. 
   */
  
  #ifndef ns_pi_h
  #define ns_pi_h
  
  #undef setbit
  
  #include "queue.h"
  #include "trace.h"
  #include "timer-handler.h"
  
  #define	DTYPE_NONE	0	/* ok, no drop */
  #define	DTYPE_FORCED	1	/* a "forced" drop */
  #define	DTYPE_UNFORCED	2	/* an "unforced" (random) drop */
  
  // Insert APPLE specific macro here
  //
  #if defined( __MACH__ ) && defined( __APPLE__ )
  #undef setbit
  #endif
  
  /*
   * Early drop parameters, supplied by user
   */
  struct edp_pi {
  	/*
  	 * User supplied.
  	 */
  	int mean_pktsize;	/* avg pkt size, linked into Tcl */
  	int bytes;		/* true if queue in bytes, false if packets */
  	int setbit;		/* true to set congestion indication bit */
  	double a, b;		 /* parameters to pi controller */
  	double w;				/* sampling frequency (# of times per second) */ 
  	double qref;		/* desired queue size */
  	edp_pi(): mean_pktsize(0), bytes(0), setbit(0), a(0.0), b(0.0), w(0.0), qref(0.0) { }
  };
  
  /*
   * Early drop variables, maintained by PI
   */
  struct edv_pi {
  	TracedDouble v_prob;	/* prob. of packet drop before "count". */
  	int count;		/* # of packets since last drop */
  	int count_bytes;	/* # of bytes since last drop */
  	int qold;
  	edv_pi() : v_prob(0.0), count(0), count_bytes(0), qold(0) { }
  };
  
  class LinkDelay;
  class PIQueue ; 
  
  class PICalcTimer : public TimerHandler {
  public:
  		PICalcTimer(PIQueue *a) : TimerHandler() { a_ = a; }
  		virtual void expire(Event *e);
  protected:
  		PIQueue *a_;
  };
  
  class PIQueue : public Queue {
   
   friend class PICalcTimer;
   public:	
  	PIQueue(const char * = "Drop");
   protected:
  	int command(int argc, const char*const* argv);
  	void enque(Packet* pkt);
  	virtual Packet *pickPacketForECN(Packet* pkt);
  	virtual Packet *pickPacketToDrop();
  	Packet* deque();
  	void reset();
  	int drop_early(Packet* pkt, int qlen);
   	double calculate_p();
  	PICalcTimer CalcTimer;
  
  	LinkDelay* link_;	/* outgoing link */
  	int fifo_;		/* fifo queue? */
  	PacketQueue *q_; 	/* underlying (usually) FIFO queue */
  		
  	int qib_;	/* bool: queue measured in bytes? */
  	NsObject* de_drop_;	/* drop_early target */
  
  	//added to be able to trace EDrop Objects - ratul
  	//the other events - forced drop, enque and deque are traced by a different mechanism.
  	NsObject * EDTrace;    //early drop trace
  	char traceType[20];    //the preferred type for early drop trace. 
  	                       //better be less than 19 chars long
  	Tcl_Channel tchan_;	/* place to write trace records */
  	TracedInt curq_;	/* current qlen seen by arrivals */
  	void trace(TracedVar*);	/* routine to write trace records */
  
  	edp_pi edp_;	/* early-drop params */
  	edv_pi edv_;		/* early-drop variables */
  
  	int first_reset_;       /* first time reset() is called */
  
  };
  
  #endif
  