kofn.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 <netinet/in.h>
#include <sys/types.h>
#include <stdlib.h>

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

int kofn_flag = FALSE;

struct KOFNEntry {
  u_int32_t neigh;
  int count;
  struct KOFNEntry *next;
};

static struct KOFNEntry *firstKOFNEntry = NULL;

static struct KOFNEntry *find(u_int32_t dest){
  struct KOFNEntry *entry = NULL;
  
  trace(TRACE_KOFN,"kofn:find(%s)",inet_fmt_h(dest,s1));

  for(entry = firstKOFNEntry
	  ; entry != NULL
	  ; entry = entry->next){

    if (entry->neigh == dest) {
      trace(TRACE_KOFN,"kofn:find:returning entry");
      return entry;
    }
  }
  trace(TRACE_KOFN,"kofn:returning NULL");
  return NULL;
}


static void removeEntry(struct KOFNEntry *entry){
  struct KOFNEntry *toMe = NULL; 
  
  trace(TRACE_KOFN,"KOFN:removeEntry");
  //go through list and find who is pointing to entry
  if(firstKOFNEntry != NULL && entry != NULL){
    trace(TRACE_KOFN,"KOFN:removeEntry(%s)"
	  ,inet_fmt_h(entry->neigh,s1));
    if(entry==firstKOFNEntry){
      trace(TRACE_KOFN,"KOFN:removeEntry==firstEntry");
      firstKOFNEntry=firstKOFNEntry->next;
      //free KOFNEntry
      free(entry);
      entry = NULL;
      return;
    }else{
      for(toMe = firstKOFNEntry
	    ; toMe != NULL
	    ; toMe = entry->next) {
	if (toMe->next == entry) {
	  trace(TRACE_KOFN,"KOFN:entry!=firstEntry");
	  toMe->next=entry->next;
	  //free KOFNEntry
	  free(entry);
	  entry = NULL;
	  return;
	}
      }
      trace(TRACE_KOFN,"KOFN: remove(entry not found)");
    }
  }
}

static void dec(u_int32_t dest){
  struct KOFNEntry *entry = NULL;
  trace(TRACE_KOFN, "dec(dest=%s"
      ,inet_fmt_h(dest,s1));
  entry=find(dest);
  if(entry != NULL){
    entry->count--;
    if(entry->count <= 0){
      removeEntry(entry);
    }
  }
}

static void insert(struct KOFNEntry *entry){
  struct KOFNEntry *first = NULL;
  first=firstKOFNEntry;
  firstKOFNEntry=entry;
  firstKOFNEntry->next=first;
}



int addkofn(u_int32_t neigh){
  struct KOFNEntry *entry = NULL;
  
  trace(TRACE_KOFN, "addkofn(neigh=%s"
      ,inet_fmt_h(neigh,s1));
  entry = find(neigh);
  
  if(entry == NULL){
    //create entry
    entry = (struct KOFNEntry *)malloc(sizeof(struct KOFNEntry));
    if(entry == NULL){
      log(LOG_ERR,TRUE,"unable to allocate memory, KOFNEntry");
    }
  
    entry->count = 1;
    entry->neigh = neigh;
    insert(entry);
  }else{
    entry->count++;
  }
  
  //set timer to decrement count
  trace(TRACE_KOFN|TRACE_TIMER
	,"kofn:timer:%u"
	,ALLOWED_HELLO_LOSS * HELLO_INTERVAL);
  timer_setTimer(ALLOWED_HELLO_LOSS * HELLO_INTERVAL
		 ,(cfunc_t)dec
		 ,(void *)neigh);
  return entry->count;
}