rrep.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 <sys/types.h>

#include "aodvConst.h"
#include "aodvMsg.h"
#include "aodvPktInfo.h"
#include "aodvSocket.h"
#include "const.h"
#include "debug.h"
#include "inet.h"
#include "localRepair.h"
#include "rerr.h"
#include "rrep.h"
#include "rreqResend.h"
#include "sendDatagram.h"
#include "routingTable.h"

#include "packet_input.h"

void fill_my_rrep(struct RREP *rrep){
  rrep->type=AODV_RREP;
  rrep->R=0;
  rrep->A=0;  //TODO FUTURE
  rrep->reserved1=0;
  rrep->reserved2=0;
  rrep->prefixSize=0; //TODO FUTURE
  rrep->hopCount=0;
  rrep->destSeqNum=htonl(mySeqNum);
  rrep->lifetime=htonl(MY_ROUTE_TIMEOUT);
}

static void fill_grat_rrep(struct RREP *rrep
			   , u_int32_t dest
			   , u_int32_t src){
  rrep->type=AODV_RREP;
  rrep->R=0;
  rrep->A=0;  //TODO FUTURE
  rrep->reserved1=0;
  rrep->reserved2=0;
  rrep->prefixSize=0; //TODO FUTURE
  rrep->src=htonl(dest);
  rrep->dest=htonl(src);
  rrep->hopCount=getHopCount(src);
  rrep->destSeqNum=htonl(getDestinationSeqNum(src));
  rrep->lifetime=htonl(getLifetime(src)-getTime());
}

static void fill_other_rrep(struct RREP *rrep
		      , u_int32_t dest, u_int32_t destSeqNum){
  rrep->type=AODV_RREP;
  rrep->R=0;
  rrep->A=0;  //TODO FUTURE
  rrep->reserved1=0;
  rrep->reserved2=0;
  rrep->prefixSize=0; //TODO FUTURE
  rrep->hopCount=getHopCount(dest) + 1;
  rrep->destSeqNum=htonl(getDestinationSeqNum(dest));
  rrep->lifetime=htonl(getLifetime(dest) - getTime());
}


void generateRREP(u_int32_t src
		  , u_int32_t dest
		  , u_int32_t destSeqNum
		  , int G){
  struct RREP rrep;
  struct AodvPktInfo info;

  trace(TRACE_RREP,"generateRREP");

  rrep.src=htonl(src);
  rrep.dest=htonl(dest);
  //check if I'm the destination
  if(getip() == htonl(dest)){

    //could be done differenty see aodv draft 8.4
    if (destSeqNum > mySeqNum){
      mySeqNum = destSeqNum;
      trace(TRACE_RT,"Changing SeqNum to %d because rrep had larger mySeqNum"
	    ,mySeqNum);
    }
    fill_my_rrep(&rrep);
  } else {
    fill_other_rrep(&rrep,dest,destSeqNum);
    addPrecursor(src,getNextHop(dest));
  }

  //create pktinfo
  fill_pktInfo(&info,getNextHop(src));

  trace(TRACE_RREP,"generateRREP: sending RREP");
  printRREP(&rrep);

  trace(TRACE_DEMO,"sending RREP to %s for %s"
	,inet_fmt_n(info.dest,s1),inet_fmt_n(rrep.src,s2));
  
  //send on datagram
  trace(TRACE_METRIC,"s RREP");
  sendDatagram(&info,&rrep,sizeof(struct RREP));
  
  if(G == 1){

    fill_grat_rrep(&rrep,dest,src);
    
    fill_pktInfo(&info,getNextHop(dest));
    
    trace(TRACE_RREP,"generateRREP: sending Grat. RREP");
    trace(TRACE_DEMO,"sending Grat. RREP to %s"
	  ,inet_fmt_h(dest,s1));
    printRREP(&rrep);
    //send on datagram
    trace(TRACE_METRIC,"s g RREP");
    sendDatagram(&info,&rrep,sizeof(struct RREP));
  }
}


void receiveRREP(struct AodvPktInfo *info
		  , struct RREP *rrep) {
  struct RoutingTableEntry *entry = NULL;
  //u_int32_t destNumInRoutingTable;
  u_int32_t hopCountInRoutingTable;
  
  trace(TRACE_RREP,"receiveRREP");

  printRREP(rrep);


  if((info->src == rrep->dest) && (rrep->hopCount == 0)){
    //this is a hello message
    updateNeighbor(ntohl(info->src),ntohl(rrep->destSeqNum));
    trace(TRACE_METRIC,"r h RREP");
    return;
  }else{
    trace(TRACE_METRIC,"r RREP");
    updateNeighbor(ntohl(info->src),0);
  }

  entry=getRoute(ntohl(rrep->dest));

  if((entry == NULL) 
     || ((entry != NULL) 
	 && ((ntohl(rrep->destSeqNum) > entry->destSeqNum) 
	     || ((ntohl(rrep->destSeqNum) == entry->destSeqNum) 
		 && ((entry->hopCount == DELETE_ROUTE) 
		     || (rrep->hopCount <= entry->hopCount)))))){

    trace(TRACE_RREP,"received RREP: updating route");
    
    removeFromRreqResend(ntohl(rrep->dest));
    if((localRepair == TRUE) && (inLRList(ntohl(rrep->dest)))){
      if(hopCountInRoutingTable < rrep->hopCount){
	createAndSendRERR(ntohl(rrep->dest),1);
      }
      removeFromLRList(ntohl(rrep->dest));
    }
    updateRoute(ntohl(info->src),rrep);

    //check if I'm the destination
    if(getip() != rrep->src){
      trace(TRACE_RREP,"received RREP: wasn't destination");
      (rrep->hopCount)++;
      addPrecursor(ntohl(rrep->dest),getNextHop(ntohl(rrep->src)));
      updateLifetime(ntohl(rrep->dest),ntohl(rrep->lifetime));
      info->dest=ntohl(getNextHop(ntohl(rrep->src)));
      info->src=getip();
      trace(TRACE_RREP,"received RREP: forwarding rrep->src=%s"
	  ,inet_fmt_n(rrep->src,s1));
      trace(TRACE_RREP,"received RREP: forwarding rrep->dest=%s"
	  ,inet_fmt_n(rrep->dest,s1));
      (info->ttl)--;
      if(info->ttl <= 0){
	return;
      }
      trace(TRACE_DEMO|TRACE_RREP
	    ,"forwarding RREP from %s to %s"
	    ,inet_fmt_n(info->src,s1),inet_fmt_n(rrep->src,s2));
      
      trace(TRACE_METRIC,"s f RREP");
      sendDatagram(info,rrep,sizeof(struct RREP));
    } else {
      packet_buff_send(ntohl(rrep->dest));
      trace(TRACE_DEMO|TRACE_RREP
	    ,"received RREP from %s: for me"
	    ,inet_fmt_n(info->src,s1),inet_fmt_n(rrep->dest,s2));
    }
  } else {
    trace(TRACE_RREP,"received RREP: larger num hops throwing away rrep");
  }

}