rreqtable.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 <stdlib.h>
#include <sys/types.h>

#include "aodvConst.h"
#include "const.h"
#include "debug.h"
#include "inet.h"
#include "routingTable.h"

struct RreqTableEntry {
  u_int32_t src;
  u_int32_t broadcastId;
  u_int32_t lifetime;
  struct RreqTableEntry *next;
};

static struct RreqTableEntry *firstRREQEntry = NULL;


static void addEntry(u_int32_t src, u_int32_t broadcastId){
  struct RreqTableEntry *first = NULL;
  struct RreqTableEntry *newEntry = NULL;
 
  trace(TRACE_RECENT_RREQ, "addEntry");
  trace(TRACE_RECENT_RREQ, "addEntry(src=%s",inet_fmt_h(src,s1));
  trace(TRACE_RECENT_RREQ, "addEntry(broadcastid=%u",broadcastId);
  
  //allocate space
  newEntry = (struct RreqTableEntry *)malloc(sizeof(struct RreqTableEntry));
  if(newEntry == NULL){
    log(LOG_ERR,TRUE,"unable to allocate memory, RreqTableEntry");
  }
  
  //fill in
  newEntry->src=src;
  newEntry->broadcastId=broadcastId;
  newEntry->next=NULL;
  newEntry->lifetime = BROADCAST_RECORD_TIME;

  //connect
  if(firstRREQEntry == NULL){
    trace(TRACE_RECENT_RREQ, "addEntry:first entry");
    firstRREQEntry=newEntry;
  } else {
    trace(TRACE_RECENT_RREQ, "addEntry:adding entry");
    first=firstRREQEntry;
    firstRREQEntry=newEntry;
    newEntry->next=first;
  } 
}


int receivedAlready(u_int32_t src, u_int32_t broadcastId){
  struct RreqTableEntry *ptr = NULL;
  trace(TRACE_RECENT_RREQ, "receivedAlready");
  ptr = firstRREQEntry;
  while(ptr != NULL) {
    if (ptr->src == src && ptr->broadcastId == broadcastId ) {
      trace(TRACE_RECENT_RREQ, "receivedAlready:TRUE");
      return TRUE;
    }
    ptr = ptr->next;
  }
  addEntry(src,broadcastId);
  trace(TRACE_RECENT_RREQ, "receivedAlready:FALSE");
  return FALSE;
}


void expireRREQBroadcasts(){
  struct RreqTableEntry *prev = NULL;
  struct RreqTableEntry *next = NULL;
  struct RreqTableEntry *entry = NULL;

  trace(TRACE_RECENT_RREQ,"expireRREQBroadcasts");
  if(firstRREQEntry != NULL) {
    trace(TRACE_RECENT_RREQ,"expireRREQBroadcasts: time=%u" 
	, getTime());
    entry = firstRREQEntry;
    while(entry != NULL){
      next=entry->next;
      //check lifetime
      if(entry->lifetime < getTime()) { 
	trace(TRACE_RECENT_RREQ,"expireRREQBroadcasts: time to do something");
	//time to delete entry
	//free RreqTableEntry
	free(entry);
	if(prev == NULL){
	  trace(TRACE_RECENT_RREQ,"expireRREQBroadcasts: prev null");
	  firstRREQEntry=next;
	}
	entry=next;
      } else {
	//check next entry
	prev=entry;
	entry=entry->next;
      }
    }
  } else {
    //nothing to do!
    trace(TRACE_RECENT_RREQ,"expireRREQBroadcasts: nothing to do");
  }
}