/* -*-	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.
 *
 *
 * Here is one set of parameters from one of my simulations:
 * 
 * ed [ q_weight=0.002 thresh=5 linterm=30 maxthresh=15
 *         mean_pktsize=500 dropmech=random-drop queue-size=60
 *         plot-file=none bytes=false doubleq=false dqthresh=50 
 *	   wait=true ]
 * 
 * 1/"linterm" is the max probability of dropping a packet. 
 * There are different options that make the code
 * more messy that it would otherwise be.  For example,
 * "doubleq" and "dqthresh" are for a queue that gives priority to
 *   small (control) packets, 
 * "bytes" indicates whether the queue should be measured in bytes 
 *   or in packets, 
 * "dropmech" indicates whether the drop function should be random-drop 
 *   or drop-tail when/if the queue overflows, and 
 *   the commented-out Holt-Winters method for computing the average queue 
 *   size can be ignored.
 * "wait" indicates whether the gateway should wait between dropping
 *   packets.
 *
 * @(#) $Header: /usr/src/mash/repository/vint/ns-2/red.h,v 1.14 1998/06/27 01:24:29 gnguyen Exp $ (LBL)
 *
 * adapted to REM 01/2000 by lmwang@cs.princeton.edu
 */

#ifndef ns_REM_h
#define ns_REM_h

#include "queue.h"
#include "timer-handler.h"

class LinkDelay;

class REMQueue;

class AggrRateTimer : public TimerHandler {
public: 
	AggrRateTimer(REMQueue *q) : TimerHandler() { q_ = q; }
protected:
	virtual void expire(Event *e);
	REMQueue *q_;
};

/*
 * early marking parameters, supplied by user
 */
struct emp {
	/*
	 * User supplied.
	 */
	int mean_pktsize;	/* avg pkt size, linked into Tcl */
	int bytes;		/* true if queue in bytes, false if packets */

        double q_w;             /* queue weight given to cur q size sample */
        int    rate_count;     
        double rate_timeout;    /* time period to measure input rate */
	double delta;		/* weight in aggregate input rate est */
	double gamma;		/* stepsize in price adjustment*/
	double alpha_l;	        /* weight of buffer in price adjustment  */
	double phi;		/* base in marking probability computing */

	/*
	 * Computed as a function of user supplied paramters.
	 */
	double ptc;		/* packet time constant in packets/second */
	emp(): ptc(0.0) {}
};

/*
 * Early marking variables, maintained by REM
 */
struct emv {
	TracedDouble v_ave;	/* average queue size */
	TracedDouble v_prob1;	/* prob. of packet drop before "count". */

        double v_slope;         /* used in computing average queue size */

	double aggr_input;	/* aggregate input rate estimate*/
	TracedDouble p_l;		/* link price */
        TracedDouble m_l;             /* current marking probability */

	emv() : v_ave(0.0), v_prob1(0.0),  v_slope(0.0), aggr_input(0.0), 
	        p_l(0.0), m_l(0.){ }
};

class REMQueue : public Queue {
 public:	
	REMQueue();
	void timeout();

 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();
	void run_estimator(int nqueued, int m);
        int  random_mark(Packet* pkt);
        void set_rate_timer();
        void updatePrice();

	LinkDelay* link_;	/* outgoing link */
	int fifo_;		/* fifo queue? */
        PacketQueue *q_; 	/* underlying (usually) FIFO queue */
		
	int bcount_;	/* byte count */
	int qib_;	/* bool: queue measuREM in bytes? */



	Tcl_Channel tchan_;	/* place to write trace records */
	TracedInt curq_;	/* current qlen seen by arrivals */
	void trace(TracedVar*);	/* routine to write trace records */

	/*
	 * Static state.
	 */
	int drop_tail_;		/* drop-tail */
	int drop_front_;	/* drop-from-front */
	int drop_rand_;		/* drop-tail, or drop random? */

	emp emp_;	/* early-drop params */


	/*
	 * Dynamic state.
	 */
	int idle_;		/* queue is idle? */
	double idletime_;	/* if so, since this time */
	emv emv_;		/* early-marking variables */
        double new_aggr_input;  /* for rate estimation */
        double last_aggr_time;

        int    aggr_bytes;     // for calculating new_aggr_input
        int    aggr_count;     

        double cur_buffer;     // for current buffer occupancy

	/* Timer */
        AggrRateTimer aggr_timer;

	void print_emp();	// for debugging
        void print_emv();
};

#endif