arp.c revision 1.2.2.2
1 1.2.2.2 brezak /* 2 1.2.2.2 brezak * Copyright (c) 1992 Regents of the University of California. 3 1.2.2.2 brezak * All rights reserved. 4 1.2.2.2 brezak * 5 1.2.2.2 brezak * This software was developed by the Computer Systems Engineering group 6 1.2.2.2 brezak * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and 7 1.2.2.2 brezak * contributed to Berkeley. 8 1.2.2.2 brezak * 9 1.2.2.2 brezak * Redistribution and use in source and binary forms, with or without 10 1.2.2.2 brezak * modification, are permitted provided that the following conditions 11 1.2.2.2 brezak * are met: 12 1.2.2.2 brezak * 1. Redistributions of source code must retain the above copyright 13 1.2.2.2 brezak * notice, this list of conditions and the following disclaimer. 14 1.2.2.2 brezak * 2. Redistributions in binary form must reproduce the above copyright 15 1.2.2.2 brezak * notice, this list of conditions and the following disclaimer in the 16 1.2.2.2 brezak * documentation and/or other materials provided with the distribution. 17 1.2.2.2 brezak * 3. All advertising materials mentioning features or use of this software 18 1.2.2.2 brezak * must display the following acknowledgement: 19 1.2.2.2 brezak * This product includes software developed by the University of 20 1.2.2.2 brezak * California, Lawrence Berkeley Laboratory and its contributors. 21 1.2.2.2 brezak * 4. Neither the name of the University nor the names of its contributors 22 1.2.2.2 brezak * may be used to endorse or promote products derived from this software 23 1.2.2.2 brezak * without specific prior written permission. 24 1.2.2.2 brezak * 25 1.2.2.2 brezak * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 1.2.2.2 brezak * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 1.2.2.2 brezak * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 1.2.2.2 brezak * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 1.2.2.2 brezak * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 1.2.2.2 brezak * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 1.2.2.2 brezak * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 1.2.2.2 brezak * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 1.2.2.2 brezak * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 1.2.2.2 brezak * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 1.2.2.2 brezak * SUCH DAMAGE. 36 1.2.2.2 brezak * 37 1.2.2.2 brezak * from @(#) Header: arp.c,v 1.5 93/07/15 05:52:26 leres Exp (LBL) 38 1.2.2.2 brezak * $Id: arp.c,v 1.2.2.2 1994/08/04 19:39:35 brezak Exp $ 39 1.2.2.2 brezak */ 40 1.2.2.2 brezak 41 1.2.2.2 brezak #include <sys/types.h> 42 1.2.2.2 brezak #include <sys/socket.h> 43 1.2.2.2 brezak #include <net/if.h> 44 1.2.2.2 brezak #include <netinet/in.h> 45 1.2.2.2 brezak 46 1.2.2.2 brezak #include <netinet/if_ether.h> 47 1.2.2.2 brezak #include <netinet/in_systm.h> 48 1.2.2.2 brezak 49 1.2.2.2 brezak #include <string.h> 50 1.2.2.2 brezak 51 1.2.2.2 brezak #include "stand.h" 52 1.2.2.2 brezak #include "net.h" 53 1.2.2.2 brezak 54 1.2.2.2 brezak /* Cache stuff */ 55 1.2.2.2 brezak #define ARP_NUM 8 /* need at most 3 arp entries */ 56 1.2.2.2 brezak 57 1.2.2.2 brezak static struct arp_list { 58 1.2.2.2 brezak n_long addr; 59 1.2.2.2 brezak u_char ea[6]; 60 1.2.2.2 brezak } arp_list[ARP_NUM] = { 61 1.2.2.2 brezak { INADDR_BROADCAST, BA } 62 1.2.2.2 brezak }; 63 1.2.2.2 brezak static int arp_num = 1; 64 1.2.2.2 brezak 65 1.2.2.2 brezak /* Local forwards */ 66 1.2.2.2 brezak static int arpsend __P((struct iodesc *, void *, int)); 67 1.2.2.2 brezak static int arprecv __P((struct iodesc *, void *, int)); 68 1.2.2.2 brezak 69 1.2.2.2 brezak /* Broadcast an ARP packet, asking who has addr on interface d */ 70 1.2.2.2 brezak u_char * 71 1.2.2.2 brezak arpwhohas(d, addr) 72 1.2.2.2 brezak register struct iodesc *d; 73 1.2.2.2 brezak n_long addr; 74 1.2.2.2 brezak { 75 1.2.2.2 brezak register int i; 76 1.2.2.2 brezak register struct ether_arp *ah; 77 1.2.2.2 brezak register struct arp_list *al; 78 1.2.2.2 brezak struct { 79 1.2.2.2 brezak u_char header[ETHER_SIZE]; 80 1.2.2.2 brezak struct ether_arp warp; 81 1.2.2.2 brezak } wbuf; 82 1.2.2.2 brezak union { 83 1.2.2.2 brezak u_char buffer[RECV_SIZE]; 84 1.2.2.2 brezak struct { 85 1.2.2.2 brezak u_char header[ETHER_SIZE]; 86 1.2.2.2 brezak struct ether_arp rarp; 87 1.2.2.2 brezak } ru; 88 1.2.2.2 brezak } rbuf; 89 1.2.2.2 brezak 90 1.2.2.2 brezak #ifdef ARP_DEBUG 91 1.2.2.2 brezak if (debug) 92 1.2.2.2 brezak printf("arpwhohas: called for %s\n", intoa(addr)); 93 1.2.2.2 brezak #endif 94 1.2.2.2 brezak /* Try for cached answer first */ 95 1.2.2.2 brezak for (i = 0, al = arp_list; i < arp_num; ++i, ++al) 96 1.2.2.2 brezak if (addr == al->addr) 97 1.2.2.2 brezak return (al->ea); 98 1.2.2.2 brezak 99 1.2.2.2 brezak /* Don't overflow cache */ 100 1.2.2.2 brezak if (arp_num > ARP_NUM - 1) 101 1.2.2.2 brezak panic("arpwhohas: overflowed arp_list!"); 102 1.2.2.2 brezak 103 1.2.2.2 brezak #ifdef ARP_DEBUG 104 1.2.2.2 brezak if (debug) 105 1.2.2.2 brezak printf("arpwhohas: not cached\n"); 106 1.2.2.2 brezak #endif 107 1.2.2.2 brezak ah = &wbuf.warp; 108 1.2.2.2 brezak bzero(ah, sizeof(*ah)); 109 1.2.2.2 brezak 110 1.2.2.2 brezak ah->arp_hrd = htons(ARPHRD_ETHER); 111 1.2.2.2 brezak ah->arp_pro = htons(ETHERTYPE_IP); 112 1.2.2.2 brezak ah->arp_hln = sizeof(ah->arp_sha); /* hardware address length */ 113 1.2.2.2 brezak ah->arp_pln = sizeof(ah->arp_spa); /* protocol address length */ 114 1.2.2.2 brezak ah->arp_op = htons(ARPOP_REQUEST); 115 1.2.2.2 brezak MACPY(d->myea, ah->arp_sha); 116 1.2.2.2 brezak bcopy(&d->myip, ah->arp_spa, sizeof(ah->arp_spa)); 117 1.2.2.2 brezak bcopy(&addr, ah->arp_tpa, sizeof(ah->arp_tpa)); 118 1.2.2.2 brezak 119 1.2.2.2 brezak /* Store ip address in cache */ 120 1.2.2.2 brezak al->addr = addr; 121 1.2.2.2 brezak 122 1.2.2.2 brezak (void)sendrecv(d, arpsend, ah, sizeof(*ah), arprecv, 123 1.2.2.2 brezak ((u_char *)&rbuf.ru.rarp) - ETHER_SIZE, 124 1.2.2.2 brezak ETHER_SIZE + sizeof(rbuf.ru.rarp)); 125 1.2.2.2 brezak 126 1.2.2.2 brezak /* Store ethernet address in cache */ 127 1.2.2.2 brezak MACPY(rbuf.ru.rarp.arp_sha, al->ea); 128 1.2.2.2 brezak ++arp_num; 129 1.2.2.2 brezak #ifdef ARP_DEBUG 130 1.2.2.2 brezak if (debug) 131 1.2.2.2 brezak printf("arpwhohas: cacheing %s --> %s\n", intoa(addr), ether_sprintf(al->ea)); 132 1.2.2.2 brezak #endif 133 1.2.2.2 brezak 134 1.2.2.2 brezak return (al->ea); 135 1.2.2.2 brezak } 136 1.2.2.2 brezak 137 1.2.2.2 brezak static int 138 1.2.2.2 brezak arpsend(d, pkt, len) 139 1.2.2.2 brezak register struct iodesc *d; 140 1.2.2.2 brezak register void *pkt; 141 1.2.2.2 brezak register int len; 142 1.2.2.2 brezak { 143 1.2.2.2 brezak #ifdef ARP_DEBUG 144 1.2.2.2 brezak if (debug) 145 1.2.2.2 brezak printf("arpsend: called\n"); 146 1.2.2.2 brezak #endif 147 1.2.2.2 brezak return (sendether(d, pkt, len, bcea, ETHERTYPE_ARP)); 148 1.2.2.2 brezak } 149 1.2.2.2 brezak 150 1.2.2.2 brezak /* Returns 0 if this is the packet we're waiting for else -1 (and errno == 0) */ 151 1.2.2.2 brezak static int 152 1.2.2.2 brezak arprecv(d, pkt, len) 153 1.2.2.2 brezak register struct iodesc *d; 154 1.2.2.2 brezak register void *pkt; 155 1.2.2.2 brezak register int len; 156 1.2.2.2 brezak { 157 1.2.2.2 brezak register struct ether_header *eh; 158 1.2.2.2 brezak register struct ether_arp *ah; 159 1.2.2.2 brezak 160 1.2.2.2 brezak #ifdef ARP_DEBUG 161 1.2.2.2 brezak if (debug) 162 1.2.2.2 brezak printf("arprecv: called\n"); 163 1.2.2.2 brezak #endif 164 1.2.2.2 brezak if (len < sizeof(*eh) + sizeof(*ah)) { 165 1.2.2.2 brezak errno = 0; 166 1.2.2.2 brezak return (-1); 167 1.2.2.2 brezak } 168 1.2.2.2 brezak 169 1.2.2.2 brezak eh = (struct ether_header *)pkt; 170 1.2.2.2 brezak 171 1.2.2.2 brezak /* Must be to us */ 172 1.2.2.2 brezak if (bcmp(d->myea, eh->ether_dhost, 6) != 0 && 173 1.2.2.2 brezak bcmp(bcea, eh->ether_dhost, 6) != 0) { 174 1.2.2.2 brezak #ifdef ARP_DEBUG 175 1.2.2.2 brezak if (debug) 176 1.2.2.2 brezak printf("arprecv: not ours %s\n", ether_sprintf(eh->ether_dhost)); 177 1.2.2.2 brezak #endif 178 1.2.2.2 brezak errno = 0; 179 1.2.2.2 brezak return (-1); 180 1.2.2.2 brezak } 181 1.2.2.2 brezak 182 1.2.2.2 brezak if (ntohs(eh->ether_type) != ETHERTYPE_ARP) { 183 1.2.2.2 brezak #ifdef ARP_DEBUG 184 1.2.2.2 brezak if (debug) 185 1.2.2.2 brezak printf("arprecv: not arp %d\n", ntohs(eh->ether_type)); 186 1.2.2.2 brezak #endif 187 1.2.2.2 brezak errno = 0; 188 1.2.2.2 brezak return (-1); 189 1.2.2.2 brezak } 190 1.2.2.2 brezak 191 1.2.2.2 brezak ah = (struct ether_arp *)(eh + 1); 192 1.2.2.2 brezak HTONS(ah->arp_hrd); 193 1.2.2.2 brezak HTONS(ah->arp_pro); 194 1.2.2.2 brezak HTONS(ah->arp_op); 195 1.2.2.2 brezak if (ah->arp_hrd != ARPHRD_ETHER || ah->arp_pro != ETHERTYPE_IP || 196 1.2.2.2 brezak ah->arp_hln != sizeof(ah->arp_sha) || 197 1.2.2.2 brezak ah->arp_pln != sizeof(ah->arp_spa) || ah->arp_op != ARPOP_REPLY) { 198 1.2.2.2 brezak #ifdef ARP_DEBUG 199 1.2.2.2 brezak if (debug) 200 1.2.2.2 brezak printf("arprecv: not valid reply\n"); 201 1.2.2.2 brezak #endif 202 1.2.2.2 brezak errno = 0; 203 1.2.2.2 brezak return (-1); 204 1.2.2.2 brezak } 205 1.2.2.2 brezak if (bcmp(&arp_list[arp_num].addr, ah->arp_spa, sizeof(long)) != 0 || 206 1.2.2.2 brezak bcmp(&d->myip, ah->arp_tpa, sizeof(d->myip)) != 0) { 207 1.2.2.2 brezak #ifdef ARP_DEBUG 208 1.2.2.2 brezak if (debug) 209 1.2.2.2 brezak printf("arprecv: already cached??\n"); 210 1.2.2.2 brezak #endif 211 1.2.2.2 brezak errno = 0; 212 1.2.2.2 brezak return (-1); 213 1.2.2.2 brezak } 214 1.2.2.2 brezak 215 1.2.2.2 brezak return (0); 216 1.2.2.2 brezak } 217
Indexes created Tue Sep 30 17:09:57 GMT 2025