/*
 * 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.
 */
/*
 *  This is a FRED implementation heavly based on the RED code (red.cc, red.h)
 *  found in ns-2 version 2.0. The differences from red.h are highlighted
 *  by comments containing "FRED" word. 
 *  Contact: Ion Stoica (istoica@cs.cmu.edu)
 *
 * @(#) $Header: /afs/cs/project/cmcl-ns2/NetBSD1.2.1/ns-allinone/ns-2/RCS/fred.h,v 1.2 1998/09/12 16:44:18 istoica Exp istoica $ (LBL)
 */

#ifndef ns_fred_h
#define ns_fred_h

#include <math.h>
#include <string.h>
#include <sys/types.h>

#include "queue.h"
#include "tclcl.h"
#include "packet.h"
#include "random.h"
#include "flags.h"
#include "delay.h"

#define MAXFLOWS 200
#define MINQ     2

// #define SRCID /* use penalty box in conjucntion with CSFQ */

/*
 * Early drop parameters, supplied by user
 */
struct edp {
  /*
   * User supplied.
   */
  int mean_pktsize;	/* avg pkt size, linked into Tcl */
  int bytes;		/* true if queue in bytes, false if packets */
  int wait;		/* true for waiting between dropped packets */
  int setbit;		/* true to set congestion indication bit */
  
  double th_min;	/* minimum threshold of average queue size */
  double th_max;	/* maximum threshold of average queue size */
  double max_p_inv;	/* 1/max_p, for max_p = maximum prob.  */
  double q_w;		/* queue weight */
				   
  /*
   * Computed as a function of user supplied paramters.
   */
  double ptc;		/* packet time constant in packets/second */
  int adjusted_for_bytes_;      /* adjusted for byte-counting
					 instead of packet-counting */
};

/*
 * Early drop variables, maintained by FRED
 */
struct edv {
  float v_ave;		/* average queue size */
  float v_slope;		/* used in computing average queue size */
  float v_r;			
  float v_prob;		/* prob. of packet drop */
  float v_prob1;		/* prob. of packet drop before "count". */
  float v_a;		/* v_prob = v_a * v_ave + v_b */
  float v_b;
  int count;		/* # of packets since last drop */
  int count_bytes;	/* # of bytes since last drop */
  int old;		/* 0 when average queue first exceeds thresh */
};

struct flowState {  /* FRED */
  int qlen;         /* FRED */
  int strike;       /* FRED */
  int present;      /* FRED */
};                  /* FRED */

class FREDQueue : public Queue {
 public:	
  FREDQueue();
 protected:
  int command(int argc, const char*const* argv);
  void enque(Packet* pkt);
  virtual Packet *pickPacketToDrop();
  Packet* deque();
  void reset();
  void run_estimator(int nqueued, int m);
  void plot();
  void plot1(int qlen);
  int drop_early(Packet* pkt);
#ifdef SRCID
  int getId(int src);
#endif 
  void check();                      /* FRED */
  void reset_flow_state(int flowId); /* FRED */
  
  LinkDelay* link_;  /* outgoing link */
  int fifo_;	     /* fifo queue? */
  PacketQueue *q_;   /* underlying FIFO queue */
  
  int bcount_;	/* byte count */
  int qib_;	/* bool: queue measured in bytes? */
  NsObject* de_drop_;	/* drop_early target */
  
  /*
   * Static state.
   */
  int drop_tail_;
  edp edp_;
  int doubleq_;	   /* for experiments with priority for small packets */
  int dqthresh_;   /* for experiments with priority for small packets */
  int many_flows_; /* specifies the mode in which FRED works */

  /*
   * Dynamic state.
   */
  int idle_;
  double idletime_;
  edv edv_;
  void print_edp();
  void print_edv();
  flowState fs_[MAXFLOWS];  /* FRED - per-flow state*/
#ifdef SRCID
  int         hashid_[MAXFLOWS];
#endif
  int       maxq;           /* FRED - maximum allowed per-flow queue size*/
  int       nactive;        /* FRED - number of active flows */
  int       off_ip_;        /* FRED */
};

#endif