uip-neighbor.c

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00001 /*
00002  * Copyright (c) 2006, Swedish Institute of Computer Science.
00003  * All rights reserved.
00004  *
00005  * Redistribution and use in source and binary forms, with or without
00006  * modification, are permitted provided that the following conditions
00007  * are met:
00008  * 1. Redistributions of source code must retain the above copyright
00009  *    notice, this list of conditions and the following disclaimer.
00010  * 2. Redistributions in binary form must reproduce the above copyright
00011  *    notice, this list of conditions and the following disclaimer in the
00012  *    documentation and/or other materials provided with the distribution.
00013  * 3. Neither the name of the Institute nor the names of its contributors
00014  *    may be used to endorse or promote products derived from this software
00015  *    without specific prior written permission.
00016  *
00017  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
00018  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
00019  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
00020  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
00021  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
00022  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
00023  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
00024  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
00025  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
00026  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
00027  * SUCH DAMAGE.
00028  *
00029  * This file is part of the Contiki operating system.
00030  *
00031  * $Id: uip-neighbor.c,v 1.3 2008/11/09 12:16:05 adamdunkels Exp $
00032  */
00033 
00034 /**
00035  * \file
00036  *         Database of link-local neighbors, used by IPv6 code and
00037  *         to be used by a future ARP code rewrite.
00038  * \author
00039  *         Adam Dunkels <adam@sics.se>
00040  */
00041 
00042 #include "net/uip-neighbor.h"
00043 
00044 #include <string.h>
00045 #include <stdio.h>
00046 
00047 #define MAX_TIME 128
00048 
00049 #ifdef UIP_NEIGHBOR_CONF_ENTRIES
00050 #define ENTRIES UIP_NEIGHBOR_CONF_ENTRIES
00051 #else /* UIP_NEIGHBOR_CONF_ENTRIES */
00052 #define ENTRIES 8
00053 #endif /* UIP_NEIGHBOR_CONF_ENTRIES */
00054 
00055 struct neighbor_entry {
00056   uip_ipaddr_t ipaddr;
00057   struct uip_neighbor_addr addr;
00058   u8_t time;
00059 };
00060 static struct neighbor_entry entries[ENTRIES];
00061 
00062 /*---------------------------------------------------------------------------*/
00063 void
00064 uip_neighbor_init(void)
00065 {
00066   int i;
00067 
00068   for(i = 0; i < ENTRIES; ++i) {
00069     entries[i].time = MAX_TIME;
00070   }
00071 }
00072 /*---------------------------------------------------------------------------*/
00073 void
00074 uip_neighbor_periodic(void)
00075 {
00076   int i;
00077 
00078   for(i = 0; i < ENTRIES; ++i) {
00079     if(entries[i].time < MAX_TIME) {
00080       entries[i].time++;
00081     }
00082   }
00083 }
00084 /*---------------------------------------------------------------------------*/
00085 void
00086 uip_neighbor_add(uip_ipaddr_t *ipaddr, struct uip_neighbor_addr *addr)
00087 {
00088   int i, oldest;
00089   u8_t oldest_time;
00090 
00091   /*  printf("Adding neighbor with link address %02x:%02x:%02x:%02x:%02x:%02x\n",
00092          addr->addr.addr[0], addr->addr.addr[1], addr->addr.addr[2], addr->addr.addr[3],
00093          addr->addr.addr[4], addr->addr.addr[5]);*/
00094   
00095   /* Find the first unused entry or the oldest used entry. */
00096   oldest_time = 0;
00097   oldest = 0;
00098   for(i = 0; i < ENTRIES; ++i) {
00099     if(entries[i].time == MAX_TIME) {
00100       oldest = i;
00101       break;
00102     }
00103     if(uip_ipaddr_cmp(&entries[i].ipaddr, ipaddr)) {
00104       oldest = i;
00105       break;
00106     }
00107     if(entries[i].time > oldest_time) {
00108       oldest = i;
00109       oldest_time = entries[i].time;
00110     }
00111   }
00112 
00113   /* Use the oldest or first free entry (either pointed to by the
00114      "oldest" variable). */
00115   entries[oldest].time = 0;
00116   uip_ipaddr_copy(&entries[oldest].ipaddr, ipaddr);
00117   memcpy(&entries[oldest].addr, addr, sizeof(struct uip_neighbor_addr));
00118 }
00119 /*---------------------------------------------------------------------------*/
00120 static struct neighbor_entry *
00121 find_entry(uip_ipaddr_t *ipaddr)
00122 {
00123   int i;
00124   
00125   for(i = 0; i < ENTRIES; ++i) {
00126     if(uip_ipaddr_cmp(&entries[i].ipaddr, ipaddr)) {
00127       return &entries[i];
00128     }
00129   }
00130   return NULL;
00131 }
00132 /*---------------------------------------------------------------------------*/
00133 void
00134 uip_neighbor_update(uip_ipaddr_t *ipaddr)
00135 {
00136   struct neighbor_entry *e;
00137 
00138   e = find_entry(ipaddr);
00139   if(e != NULL) {
00140     e->time = 0;
00141   }
00142 }
00143 /*---------------------------------------------------------------------------*/
00144 struct uip_neighbor_addr *
00145 uip_neighbor_lookup(uip_ipaddr_t *ipaddr)
00146 {
00147   struct neighbor_entry *e;
00148 
00149   e = find_entry(ipaddr);
00150   if(e != NULL) {
00151     /*    printf("Lookup neighbor with link address %02x:%02x:%02x:%02x:%02x:%02x\n",
00152            e->addr.addr.addr[0], e->addr.addr.addr[1], e->addr.addr.addr[2], e->addr.addr.addr[3],
00153            e->addr.addr.addr[4], e->addr.addr.addr[5]);*/
00154 
00155     return &e->addr;
00156   }
00157   return NULL;
00158 }
00159 /*---------------------------------------------------------------------------*/

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