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# uip/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 uIP TCP/IP stack
    00030  *
    00031  * $Id: uip-neighbor.c,v 1.2 2006/06/12 08:00:30 adam 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 "uip-neighbor.h"
    00043
    00044 #include <string.h>
    00045
    00046 #define MAX_TIME 128
    00047
    00048 #ifdef UIP_NEIGHBOR_CONF_ENTRIES
    00049 #define ENTRIES UIP_NEIGHBOR_CONF_ENTRIES
    00050 #else /* UIP_NEIGHBOR_CONF_ENTRIES */
    00051 #define ENTRIES 8
    00052 #endif /* UIP_NEIGHBOR_CONF_ENTRIES */
    00053
    00054 struct neighbor_entry {
    00055   uip_ipaddr_t ipaddr;
    00056   struct uip_neighbor_addr addr;
    00057   u8_t time;
    00058 };
    00059 static struct neighbor_entry entries[ENTRIES];
    00060
    00061 /*---------------------------------------------------------------------------*/
    00062 void
    00063 uip_neighbor_init(void)
    00064 {
    00065   int i;
    00066
    00067   for(i = 0; i < ENTRIES; ++i) {
    00068     entries[i].time = MAX_TIME;
    00069   }
    00070 }
    00071 /*---------------------------------------------------------------------------*/
    00072 void
    00073 uip_neighbor_periodic(void)
    00074 {
    00075   int i;
    00076
    00077   for(i = 0; i < ENTRIES; ++i) {
    00078     if(entries[i].time < MAX_TIME) {
    00079       entries[i].time++;
    00080     }
    00081   }
    00082 }
    00083 /*---------------------------------------------------------------------------*/
    00084 void
    00085 uip_neighbor_add(uip_ipaddr_t ipaddr, struct uip_neighbor_addr *addr)
    00086 {
    00087   int i, oldest;
    00088   u8_t oldest_time;
    00089
    00090   printf("Adding neighbor with link address %02x:%02x:%02x:%02x:%02x:%02x\n",
    00091          addr->addr.addr[0], addr->addr.addr[1], addr->addr.addr[2], addr->addr.addr[3],
    00092          addr->addr.addr[4], addr->addr.addr[5]);
    00093
    00094   /* Find the first unused entry or the oldest used entry. */
    00095   oldest_time = 0;
    00096   oldest = 0;
    00097   for(i = 0; i < ENTRIES; ++i) {
    00098     if(entries[i].time == MAX_TIME) {
    00099       oldest = i;
    00100       break;
    00101     }
    00102     if(uip_ipaddr_cmp(entries[i].ipaddr, addr)) {
    00103       oldest = i;
    00104       break;
    00105     }
    00106     if(entries[i].time > oldest_time) {
    00107       oldest = i;
    00108       oldest_time = entries[i].time;
    00109     }
    00110   }
    00111
    00112   /* Use the oldest or first free entry (either pointed to by the
    00113      "oldest" variable). */
    00114   entries[oldest].time = 0;
    00115   uip_ipaddr_copy(entries[oldest].ipaddr, ipaddr);
    00116   memcpy(&entries[oldest].addr, addr, sizeof(struct uip_neighbor_addr));
    00117 }
    00118 /*---------------------------------------------------------------------------*/
    00119 static struct neighbor_entry *
    00120 find_entry(uip_ipaddr_t ipaddr)
    00121 {
    00122   int i;
    00123
    00124   for(i = 0; i < ENTRIES; ++i) {
    00125     if(uip_ipaddr_cmp(entries[i].ipaddr, ipaddr)) {
    00126       return &entries[i];
    00127     }
    00128   }
    00129   return NULL;
    00130 }
    00131 /*---------------------------------------------------------------------------*/
    00132 void
    00133 uip_neighbor_update(uip_ipaddr_t ipaddr)
    00134 {
    00135   struct neighbor_entry *e;
    00136
    00137   e = find_entry(ipaddr);
    00138   if(e != NULL) {
    00139     e->time = 0;
    00140   }
    00141 }
    00142 /*---------------------------------------------------------------------------*/
    00143 struct uip_neighbor_addr *
    00144 uip_neighbor_lookup(uip_ipaddr_t ipaddr)
    00145 {
    00146   struct neighbor_entry *e;
    00147
    00148   e = find_entry(ipaddr);
    00149   if(e != NULL) {
    00150     /*    printf("Lookup neighbor with link address %02x:%02x:%02x:%02x:%02x:%02x\n",
    00151            e->addr.addr.addr[0], e->addr.addr.addr[1], e->addr.addr.addr[2], e->addr.addr.addr[3],
    00152            e->addr.addr.addr[4], e->addr.addr.addr[5]);*/
    00153
    00154     return &e->addr;
    00155   }
    00156   return NULL;
    00157 }
    00158 /*---------------------------------------------------------------------------*/