/*
 * Copyright (c) 2000 Nortel Networks
 * 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 Nortel Networks.
 * 4. The name of the Nortel Networks may not be used
 *    to endorse or promote products derived from this software without
 *    specific prior written permission.
 * 
 * THIS SOFTWARE IS PROVIDED BY NORTEL 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 NORTEL 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.
 *
 * Developed by: Farhan Shallwani, Jeremy Ethridge
 *               Peter Pieda, and Mandeep Baines
 * Maintainer: Peter Pieda <ppieda@nortelnetworks.com>
 */

#include <stdio.h>
#include "ip.h"
#include "dsred.h"
#include "delay.h"
#include "random.h"
#include "flags.h"
#include "tcp.h"
#include "dsredq.h"


/*------------------------------------------------------------------------------
dsREDClass declaration. 
    Links the new class in the TCL heirarchy.  See "Notes And Documentation for 
ns-2."
------------------------------------------------------------------------------*/
static class dsREDClass : public TclClass {
public:
	dsREDClass() : TclClass("Queue/dsRED") {}
	TclObject* create(int, const char*const*) {
		return (new dsREDQueue);
	}
} class_dsred;


/*------------------------------------------------------------------------------
dsREDQueue() Constructor.
    Initializes the queue.  Note that the default value assigned to numQueues 
in tcl/lib/ns-default.tcl must be no greater than MAX_QUEUES (the physical 
queue array size).
------------------------------------------------------------------------------*/
dsREDQueue::dsREDQueue() : de_drop_(NULL), link_(NULL)   {
  bind("numQueues_", &numQueues_);
  bind_bool("ecn_", &ecn_);
  int i;
  
  numPrec = MAX_PREC;
  schedMode = schedModeRR;
  
  for(i=0;i<MAX_QUEUES;i++){
    queueMaxRate[i] = 0;
    queueWeight[i]=1;
  }
  
  queuesDone = MAX_QUEUES;
  phbEntries = 0;		// Number of entries in PHB table
  
  reset();
}

// RED queues initilization
void dsREDQueue::reset() {
  int i;
  
  qToDq = 0;		// q to be dequed, initialized to 0	
  
  for(i=0;i<MAX_QUEUES;i++){
    queueAvgRate[i] = 0.0;
    queueArrTime[i] = 0.0;
    slicecount[i]=0;
    pktcount[i]=0;
    wirrTemp[i]=0;
    wirrqDone[i]=0;
  }
  
  stats.drops = 0;
  stats.edrops = 0;
  stats.pkts = 0;
  
  for(i=0;i<MAX_CP;i++){
    stats.drops_CP[i]=0;
    stats.edrops_CP[i]=0;
    stats.pkts_CP[i]=0;
  }
  
  for (i = 0; i < MAX_QUEUES; i++)
    redq_[i].qlim = limit();
  
  // Compute the "packet time constant" if we know the
  // link bandwidth.  The ptc is the max number of (avg sized)
  // pkts per second which can be placed on the link.
  if (link_)
    for (int i = 0; i < MAX_QUEUES; i++)
      redq_[i].setPTC(link_->bandwidth());
  
  Queue::reset();
}


/*-----------------------------------------------------------------------------
void edrop(Packet* pkt)
    This method is used so that flowmonitor can monitor early drops.
-----------------------------------------------------------------------------*/
void dsREDQueue::edrop(Packet* p)
{

	if (de_drop_ != 0){
		de_drop_->recv(p);
	}
	else {
		drop(p);
	}
}

/*-----------------------------------------------------------------------------
void applyTSWMeter(int q_id, int pkt_size)
Update the average rate for a physical Q (indicated by q_id).
Pre: policy's variables avgRate, arrivalTime, and winLen hold valid values;
  pkt_size specifies the bytes just dequeued (0 means no packet dequeued).
Post: Adjusts policy's TSW state variables avgRate and arrivalTime 
  (also called tFront) according to the bytes sent.
Note: See the paper "Explicit Allocation of Best effor Delivery Service" (David
  Clark and Wenjia Fang), Section 3.3, for a description of the TSW Tagger.
-----------------------------------------------------------------------------*/
void dsREDQueue::applyTSWMeter(int q_id, int pkt_size) {
  double now, bytesInTSW, newBytes;
  double winLen = 1.0;

  bytesInTSW = queueAvgRate[q_id] * winLen;

  // Modified by xuanc(xuanc@isi.edu) Oct 18, 2001, 
  // referring to the patch contributed by 
  // Sergio Andreozzi <sergio.andreozzi@lut.fi>
  newBytes = bytesInTSW + pkt_size;

  // Calculate the average rate (SW)
  now = Scheduler::instance().clock();
  queueAvgRate[q_id] = newBytes / (now - queueArrTime[q_id] + winLen);
  queueArrTime[q_id] = now;
}


/*-----------------------------------------------------------------------------
void enque(Packet* pkt) 
    The following method outlines the enquing mechanism for a Diffserv router.
This method is not used by the inheriting classes; it only serves as an 
outline.
-----------------------------------------------------------------------------*/
void dsREDQueue::enque(Packet* pkt) {
  int codePt, eq_id, prec;
  hdr_ip* iph = hdr_ip::access(pkt);
  //extracting the marking done by the edge router
  codePt = iph->prio();	
  int ecn = 0;
  
  //looking up queue and prec numbers for that codept
  lookupPHBTable(codePt, &eq_id, &prec);	

  // code added for ECN support
  //hdr_flags* hf = (hdr_flags*)(pkt->access(off_flags_));
  // Changed for the latest version instead of 2.1b6
  hdr_flags* hf = hdr_flags::access(pkt);

  if (ecn_ && hf->ect()) ecn = 1;
  
  stats.pkts_CP[codePt]++;
  stats.pkts++;
  
  switch(redq_[eq_id].enque(pkt, prec, ecn)) {
  case PKT_ENQUEUED:
    break;
  case PKT_DROPPED:
    stats.drops_CP[codePt]++;
    stats.drops++;
    drop(pkt);
         break;
  case PKT_EDROPPED:
    stats.edrops_CP[codePt]++;
    stats.edrops++;
    edrop(pkt);
    break;
  case PKT_MARKED:
    hf->ce() = 1; 	// mark Congestion Experienced bit		
    break;			
  default:
    break;
  }
}

// Dequing mechanism for both edge and core router.
Packet* dsREDQueue::deque() {
  Packet *p = NULL;
  int queue, prec;
  int dq_id;

  // Select queue to deque under the scheduling scheme specified.
  dq_id = selectQueueToDeque();
  
  // Dequeue a packet from the underlying queue:
  if (dq_id < numQueues_) 
    p = redq_[dq_id].deque();
  
  if (p) { 
    pktcount[dq_id]+=1;
    
    // update the average rate for pri-queue
    // Modified by xuanc(xuanc@isi.edu) Oct 18, 2001, 
    // referring to the patch contributed by 
    // Sergio Andreozzi <sergio.andreozzi@lut.fi>
    // When there is a packet dequeued, 
    // update the average rate of each queue ()
    if (schedMode==schedModePRI) 
      for (int i=0;i<numQueues_;i++) 
	if (queueMaxRate[i]) 
	  applyTSWMeter(i, (i == dq_id) ? hdr_cmn::access(p)->size() : 0); 

    // Get the precedence level (or virtual queue id)
    // for the packet dequeued.
    lookupPHBTable(getCodePt(p), &queue, &prec);
    
    // decrement virtual queue length
    // Previously in updateREDStateVar, moved by xuanc (12/03/01)
    //redq_[dq_id].qParam_[prec].qlen--;	
    redq_[dq_id].updateVREDLen(prec);	
    // update state variables for that "virtual" queue
    redq_[dq_id].updateREDStateVar(prec);
  }
  
  // Return the dequed packet:	
  return(p);
}

//    Extracts the code point marking from packet header.
int dsREDQueue::getCodePt(Packet *p) {
  hdr_ip* iph = hdr_ip::access(p);
  return(iph->prio());
}

// Reutrn the id of physical queue to be dequeued
int dsREDQueue::selectQueueToDeque() {
  // If the queue to be dequed has no elements, 
  // look for the next queue in line
  int i = 0;
  
  // Round-Robin
  if(schedMode==schedModeRR){
    //printf("RR\n");
    qToDq = ((qToDq + 1) % numQueues_);
    while ((i < numQueues_) && (redq_[qToDq].getRealLength() == 0)) {
      qToDq = ((qToDq + 1) % numQueues_);			
      i++;
    }
  } else if (schedMode==schedModeWRR) { // Weighted Round Robin
    if(wirrTemp[qToDq]<=0){
      qToDq = ((qToDq + 1) % numQueues_);
      wirrTemp[qToDq] = queueWeight[qToDq] - 1;
    } else {
      wirrTemp[qToDq] = wirrTemp[qToDq] -1;
    }			
    while ((i < numQueues_) && (redq_[qToDq].getRealLength() == 0)) {
      wirrTemp[qToDq] = 0;
      qToDq = ((qToDq + 1) % numQueues_);
      wirrTemp[qToDq] = queueWeight[qToDq] - 1;
      i++;
    }
  } else if (schedMode==schedModeWIRR) {
    qToDq = ((qToDq + 1) % numQueues_);
    while ((i<numQueues_) && ((redq_[qToDq].getRealLength()==0) || (wirrqDone[qToDq]))) {
      if (!wirrqDone[qToDq]) {
	queuesDone++;
	wirrqDone[qToDq]=1;
      }
      qToDq = ((qToDq + 1) % numQueues_);
      i++;
    }
    
    if (wirrTemp[qToDq] == 1) {
      queuesDone +=1;
      wirrqDone[qToDq]=1;
    }
    wirrTemp[qToDq]-=1;
    if(queuesDone >= numQueues_) {
      queuesDone = 0;
      for(i=0;i<numQueues_;i++) {
	wirrTemp[i] = queueWeight[i];
	wirrqDone[i]=0;
      }   	
    }
  } else if (schedMode==schedModePRI) {
    // Find the queue with highest priority, which satisfies:
    // 1. nozero queue length; and either
    // 2.1. has no MaxRate specified; or
    // 2.2. has MaxRate specified and 
    //          its average rate is not beyond that limit.
    i = 0;
    while (i < numQueues_ && 
	   (redq_[i].getRealLength() == 0 ||
	    (queueMaxRate[i] && queueAvgRate[i]>queueMaxRate[i]))){
      i++;
    }
    qToDq = i;

    // If no queue satisfies the condition above,
    // find the Queue with highest priority, 
    // which has packet to dequeue.
    // NOTE: the high priority queue can still have its packet dequeued
    //       even if its average rate has beyond the MAX rate specified!
    //       Ideally, a NO_PACKET_TO_DEQUEUE should be returned.
    if (i == numQueues_) {
      i = qToDq = 0;
      while ((i < numQueues_) && (redq_[qToDq].getRealLength() == 0)) {
	qToDq = ((qToDq + 1) % numQueues_);
	i++;
      }
    }
  }
  return(qToDq);
}	

/*-----------------------------------------------------------------------------
void lookupPHBTable(int codePt, int* queue, int* prec)
    Assigns the queue and prec parameters values corresponding to a given code 
point.  The code point is assumed to be present in the PHB table.  If it is 
not, an error message is outputted and queue and prec are undefined.
-----------------------------------------------------------------------------*/
void dsREDQueue::lookupPHBTable(int codePt, int* queue, int* prec) {
  for (int i = 0; i < phbEntries; i++) {
    if (phb_[i].codePt_ == codePt) {
      *queue = phb_[i].queue_;
      *prec = phb_[i].prec_;
      return;
    }
  }
  // quiet the compiler
  *queue = 0;
  *prec = 0;
  printf("ERROR: No match found for code point %d in PHB Table.\n", codePt);
  assert (false);
}

/*-----------------------------------------------------------------------------
void addPHBEntry(int codePt, int queue, int prec)
    Add a PHB table entry.  (Each entry maps a code point to a queue-precedence
pair.)
-----------------------------------------------------------------------------*/
void dsREDQueue::addPHBEntry(int codePt, int queue, int prec) {
  if (phbEntries == MAX_CP) {
    printf("ERROR: PHB Table size limit exceeded.\n");
  } else {
    phb_[phbEntries].codePt_ = codePt;
    phb_[phbEntries].queue_ = queue;
    phb_[phbEntries].prec_ = prec;
    stats.valid_CP[codePt] = 1;
    phbEntries++;
  }
}

/*-----------------------------------------------------------------------------
void addPHBEntry(int codePt, int queue, int prec)
    Add a PHB table entry.  (Each entry maps a code point to a queue-precedence
pair.)
-----------------------------------------------------------------------------*/
double dsREDQueue::getStat(int argc, const char*const* argv) {

	if (argc == 3) {
		if (strcmp(argv[2], "drops") == 0)
         return (stats.drops*1.0);
		if (strcmp(argv[2], "edrops") == 0)
         return (stats.edrops*1.0);
		if (strcmp(argv[2], "pkts") == 0)
         return (stats.pkts*1.0);
   }
	if (argc == 4) {
		if (strcmp(argv[2], "drops") == 0)
         return (stats.drops_CP[atoi(argv[3])]*1.0);
		if (strcmp(argv[2], "edrops") == 0)
         return (stats.edrops_CP[atoi(argv[3])]*1.0);
		if (strcmp(argv[2], "pkts") == 0)
         return (stats.pkts_CP[atoi(argv[3])]*1.0);
	}
	return -1.0;
}


/*------------------------------------------------------------------------------
void setNumPrec(int prec) 
    Sets the current number of drop precendences.  The number of precedences is
the number of virtual queues per physical queue.
------------------------------------------------------------------------------*/
void dsREDQueue::setNumPrec(int prec) {
	int i;

	if (prec > MAX_PREC) {
		printf("ERROR: Cannot declare more than %d prcedence levels (as defined by MAX_PREC)\n",MAX_PREC);
	} else {
		numPrec = prec;

		for (i = 0; i < MAX_QUEUES; i++)
			redq_[i].numPrec = numPrec;
	}
}

/*------------------------------------------------------------------------------
void setMREDMode(const char* mode)
   sets up the average queue accounting mode.
----------------------------------------------------------------------------*/
void dsREDQueue::setMREDMode(const char* mode, const char* queue) {
  int i;
  mredModeType tempMode;
  
  if (strcmp(mode, "RIO-C") == 0)
    tempMode = rio_c;
  else if (strcmp(mode, "RIO-D") == 0)
    tempMode = rio_d;
  else if (strcmp(mode, "WRED") == 0)
    tempMode = wred;
  else if (strcmp(mode, "DROP") == 0)
    tempMode = dropTail;
  else {
    printf("Error: MRED mode %s does not exist\n",mode);
    return;
  }
  
  if (!queue)
    for (i = 0; i < MAX_QUEUES; i++)
      redq_[i].mredMode = tempMode;
  else
    redq_[atoi(queue)].mredMode = tempMode;
}


/*------------------------------------------------------------------------------
void printPHBTable()
    Prints the PHB Table, with one entry per line.
------------------------------------------------------------------------------*/
void dsREDQueue::printPHBTable() {
   printf("PHB Table:\n");
   for (int i = 0; i < phbEntries; i++)
      printf("Code Point %d is associated with Queue %d, Precedence %d\n", phb_[i].codePt_, phb_[i].queue_, phb_[i].prec_);
   printf("\n");
}


/*------------------------------------------------------------------------------
void printStats()
    An output method that may be altered to assist debugging.
------------------------------------------------------------------------------*/
void dsREDQueue::printStats() {
	printf("\nPackets Statistics\n");
	printf("=======================================\n");
	printf(" CP  TotPkts   TxPkts   ldrops   edrops\n");
	printf(" --  -------   ------   ------   ------\n");
	printf("All %8ld %8ld %8ld %8ld\n",stats.pkts,stats.pkts-stats.drops-stats.edrops,stats.drops,stats.edrops);
	for (int i = 0; i < MAX_CP; i++)
		if (stats.pkts_CP[i] != 0)
			printf("%3d %8ld %8ld %8ld %8ld\n",i,stats.pkts_CP[i],stats.pkts_CP[i]-stats.drops_CP[i]-stats.edrops_CP[i],stats.drops_CP[i],stats.edrops_CP[i]);

}


void dsREDQueue::printWRRcount() {
   int i;
   for (i = 0; i < numQueues_; i++){
      printf("%d: %d %d %d.\n", i, slicecount[i],pktcount[i],queueWeight[i]);
   }
}


/*------------------------------------------------------------------------------
void setSchedularMode(int schedtype)
   sets up the schedular mode.
----------------------------------------------------------------------------*/
void dsREDQueue::setSchedularMode(const char* schedtype) {
	if (strcmp(schedtype, "RR") == 0)
   	schedMode = schedModeRR;
	else if (strcmp(schedtype, "WRR") == 0)
		schedMode = schedModeWRR;
	else if (strcmp(schedtype, "WIRR") == 0)
		schedMode = schedModeWIRR;
	else if (strcmp(schedtype, "PRI") == 0)
		schedMode = schedModePRI;
	else
		printf("Error: Scheduler type %s does not exist\n",schedtype);
}


/*------------------------------------------------------------------------------
void addQueueWeights(int queueNum, int weight)
   An input method to set the individual Queue Weights.
----------------------------------------------------------------------------*/
void dsREDQueue::addQueueWeights(int queueNum, int weight) {
  if(queueNum < MAX_QUEUES){
    queueWeight[queueNum]=weight;
  } else {
    printf("The queue number is out of range.\n");
  }
}

//Set the individual Queue Max Rates for Priority Queueing.
void dsREDQueue::addQueueRate(int queueNum, int rate) {
  if(queueNum < MAX_QUEUES){
    // Convert to BYTE/SECOND
    queueMaxRate[queueNum]=(double)rate/8.0;
  } else {
    printf("The queue number is out of range.\n");
  }
}

/*-----------------------------------------------------------------------------
int command(int argc, const char*const* argv)
    Commands from the ns file are interpreted through this interface.
-----------------------------------------------------------------------------*/
int dsREDQueue::command(int argc, const char*const* argv) {
  if (strcmp(argv[1], "configQ") == 0) {
    // modification to set the parameter q_w by Thilo
    redq_[atoi(argv[2])].config(atoi(argv[3]), argc, argv);
    return(TCL_OK);
  }
  if (strcmp(argv[1], "addPHBEntry") == 0) {
    addPHBEntry(atoi(argv[2]), atoi(argv[3]), atoi(argv[4]));
    return (TCL_OK);
  }
  if (strcmp(argv[1], "meanPktSize") == 0) {
    for (int i = 0; i < MAX_QUEUES; i++)
      redq_[i].setMPS(atoi(argv[2]));
    return(TCL_OK);
  }
  if (strcmp(argv[1], "setNumPrec") == 0) {
    setNumPrec(atoi(argv[2]));
    return(TCL_OK);
  }
  if (strcmp(argv[1], "getAverage") == 0) {
    Tcl& tcl = Tcl::instance();
    tcl.resultf("%f", redq_[atoi(argv[2])].getWeightedLength());
    return(TCL_OK);
  }
  if (strcmp(argv[1], "getStat") == 0) {
    Tcl& tcl = Tcl::instance();
    tcl.resultf("%f", getStat(argc,argv));
    return(TCL_OK);
  }
  if (strcmp(argv[1], "getCurrent") == 0) {
    Tcl& tcl = Tcl::instance();
    tcl.resultf("%f", redq_[atoi(argv[2])].getRealLength()*1.0);
    return(TCL_OK);
  }
  if (strcmp(argv[1], "printStats") == 0) {
    printStats();
    return (TCL_OK);
  }
  if (strcmp(argv[1], "printWRRcount") == 0) {
    printWRRcount();
    return (TCL_OK);
  }
  if (strcmp(argv[1], "printPHBTable") == 0) {
    printPHBTable();
    return (TCL_OK);
  }
  if (strcmp(argv[1], "link") == 0) {
    Tcl& tcl = Tcl::instance();
    LinkDelay* del = (LinkDelay*) TclObject::lookup(argv[2]);
    if (del == 0) {
      tcl.resultf("RED: no LinkDelay object %s",
		  argv[2]);
      return(TCL_ERROR);
    }
    link_ = del;
    return (TCL_OK);
  }
  if (strcmp(argv[1], "early-drop-target") == 0) {
    Tcl& tcl = Tcl::instance();
    NsObject* p = (NsObject*)TclObject::lookup(argv[2]);
    if (p == 0) {
      tcl.resultf("no object %s", argv[2]);
      return (TCL_ERROR);
    }
    de_drop_ = p;
    return (TCL_OK);
  }
  if (strcmp(argv[1], "setSchedularMode") == 0) {
    setSchedularMode(argv[2]);
    return(TCL_OK);
  }
  if (strcmp(argv[1], "setMREDMode") == 0) {
    if (argc == 3)
      setMREDMode(argv[2],0);
    else
      setMREDMode(argv[2],argv[3]);
    return(TCL_OK);
  }
  if (strcmp(argv[1], "addQueueWeights") == 0) {
    addQueueWeights(atoi(argv[2]), atoi(argv[3]));
    return(TCL_OK);
  }
  if (strcmp(argv[1], "addQueueRate") == 0) {
    addQueueRate(atoi(argv[2]), atoi(argv[3]));
    return(TCL_OK);
  }
  // Returns the weighted RED queue length for one virtual queue in packets
  // Added by Thilo
  if (strcmp(argv[1], "getAverageV") == 0) {
    Tcl& tcl = Tcl::instance();
    tcl.resultf("%f",
		redq_[atoi(argv[2])].getWeightedLength_v(atoi(argv[3])));
    return(TCL_OK);
  } 
  // Returns the length of one virtual queue, in packets 
  // Added by Thilo
  if (strcmp(argv[1], "getCurrentV") == 0) {
    Tcl& tcl = Tcl::instance();
    tcl.resultf("%f",
		redq_[atoi(argv[2])].getRealLength_v(atoi(argv[3]))*1.0);
    return(TCL_OK);
  }

  return(Queue::command(argc, argv));
}