rreq.c

ucsb大学开发的aodv路由协议代码。

/*
 * Copyright (C) 2001, University of California, Santa Barbara
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * 
 * 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.
 * 
 * Other copyrights might apply to parts of this software and are so
 * noted when applicable.
 */

/*
 * Parts of this program has been derived from PIM sparse-mode pimd.
 * The pimd program is covered by the license in the accompanying file
 * named "LICENSE.pimd".
 *  
 * The pimd program is COPYRIGHT 1998 by University of Southern California.
 *
 */
#include <arpa/inet.h>
#include <errno.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>

#include "aodvConst.h"
#include "aodvMsg.h"
#include "aodvSocket.h"
#include "const.h"
#include "debug.h"
#include "inet.h"
#include "routingTable.h"
#include "routingTableEntry.h"
#include "rrep.h"
#include "rreq.h"
#include "rreqResend.h"
#include "rreqTable.h"
#include "sendDatagram.h"

int expandingRingSearch = FALSE;

//TODO FUTURE HOW DO YOU KNOW WHAT TO PUT IN G?

struct RREQ *newRREQ(u_int32_t dest, unsigned int G) {
  struct RREQ *rreq;
  trace(TRACE_RREQ,"newRREQ");
  rreq = (struct RREQ *)malloc(sizeof(struct RREQ));
  if(rreq == NULL){
    log(LOG_ERR,TRUE,"unable to allocate memory, RREQ");
  }
  
  rreq->type = AODV_RREQ;
  rreq->J = 0;  //TODO FUTURE what should go here? 
  rreq->R = 0;  //TODO FUTURE what should go here? 
  rreq->G = G; 
  rreq->reserved1 = 0;
  rreq->reserved2 = 0;
  rreq->hopCount = 0;
  rreq->broadcastId = htonl(broadcastId++);
  rreq->dest = htonl(dest);
  rreq->destSeqNum = htonl(getDestinationSeqNum(dest));
  rreq->src = getip();
  mySeqNum++;
  rreq->srcSeqNum = htonl(mySeqNum);
  return rreq;
}

void receiveRREQ(struct AodvPktInfo *info , struct RREQ *rreq) {
  struct RoutingTableEntry *rt_dst = NULL;
  //u_int32_t destSeqNumInRoutingTable;
  if(rreq->src == getip()){
    //disregard rreq from self
    trace(TRACE_RREQ,"received RREQ - disregarding because from self");
    printRREQ(rreq);
    return;
  }
  trace(TRACE_RREQ,"received RREQ");
  printRREQ(rreq);
  updateNeighbor(ntohl(info->src),0);
  if(!receivedAlready(ntohl(rreq->src),ntohl(rreq->broadcastId))){
    trace(TRACE_DEMO,"received RREQ from host %s"
	  ,inet_fmt_n(info->src,s1));
    trace(TRACE_DEMO,"received RREQ src:%s dst:%s"
	  ,inet_fmt_n(rreq->src,s1)
	  ,inet_fmt_n(rreq->dest,s2));

    //always
    updateReverseRoute(ntohl(info->src),rreq);
    rt_dst = getRoute(ntohl(rreq->dest));
    if(rreq->dest==getip()){
      //I'm the destintation
      trace(TRACE_RREQ,"received RREQ: this is the destination");
      generateRREP(ntohl(rreq->src)
		   ,ntohl(rreq->dest)
		   ,ntohl(rreq->destSeqNum)
		   ,rreq->G);
    }else if((rt_dst != NULL) 
	     && (rt_dst->hopCount != DELETE_ROUTE) 
	     && (rt_dst->destSeqNum >= ntohl(rreq->destSeqNum))){
      trace(TRACE_RREQ,"received RREQ: have active route");
      generateRREP(ntohl(rreq->src)
		   ,ntohl(rreq->dest)
		   ,ntohl(rreq->destSeqNum)
		   ,rreq->G);
    }else {
      //if((rt_dst == NULL) || (rt_dst->hopCount == DELETE_ROUTE)){
      trace(TRACE_RREQ,"received RREQ: no active route");
      rt_dst = getRoute(ntohl(rreq->dest));
      rreq->hopCount++;
      //fill out pktinfo
      info->src=getip();
      info->dest=BROADCAST;
      (info->ttl)--;
      //check TTL
      if (info->ttl > 0){
	//set destSeqNum
	if((rt_dst != NULL) && (ntohl(rreq->destSeqNum) < rt_dst->destSeqNum)){
	  rreq->destSeqNum = htonl(rt_dst->destSeqNum);
	}
	trace(TRACE_RREQ,"forwarding RREQ %s:%u"
	      ,inet_fmt_n(rreq->src,s1),ntohl(rreq->srcSeqNum));
	trace(TRACE_DEMO,"forwarding RREQ %s"
	      ,inet_fmt_n(rreq->src,s1));
	printRREQ(rreq);
	trace(TRACE_METRIC,"s f RREQ");
	sendDatagram(info,rreq,sizeof(struct RREQ));
      }
    }
  }
}


void generateRREQ(u_int32_t dest,unsigned int G){
  struct RREQ *rreq = NULL;
  struct AodvPktInfo *info = NULL;
  int lastHopCount;

  //check if RREQ already pending
  if(rreqPending(dest)){
    trace(TRACE_RREQ,"rreq already pending"); 
    return;
  }

  trace(TRACE_RREQ,"generateRREQ"); 
  rreq = newRREQ(dest,G);
  info = new_pktInfo(BROADCAST);

  if(expandingRingSearch == TRUE){
    lastHopCount = getTTL(dest);
    if(lastHopCount == 0) {
      info->ttl = TTL_START;
    } else {
      info->ttl = lastHopCount + TTL_INCREMENT;
    } 
  }

  //insertRREQintoResendList handles timers for resend
  insertRREQIntoResendList(info,rreq);
  trace(TRACE_RREQ|TRACE_DEMO,"generate RREQ for %s"
	,inet_fmt_n(rreq->dest,s1));
  printRREQ(rreq);
  trace(TRACE_METRIC,"s RREQ");
  sendDatagram(info,rreq,sizeof(struct RREQ));
}