1 /* 2 * Copyright (c) 1992 Regents of the University of California. 3 * All rights reserved. 4 * 5 * This software was developed by the Computer Systems Engineering group 6 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and 7 * contributed to Berkeley. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by the University of 20 * California, Lawrence Berkeley Laboratory and its contributors. 21 * 4. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * from @(#) Header: arp.c,v 1.5 93/07/15 05:52:26 leres Exp (LBL) 38 * $Id: arp.c,v 1.1 1994/05/08 16:11:16 brezak Exp $ 39 */ 40 41 #include <sys/types.h> 42 #include <sys/socket.h> 43 #include <net/if.h> 44 #include <netinet/in.h> 45 46 #include <netinet/if_ether.h> 47 #include <netinet/in_systm.h> 48 49 #include <errno.h> 50 #include <string.h> 51 52 #include "stand.h" 53 #include "net.h" 54 55 /* Cache stuff */ 56 #define ARP_NUM 8 /* need at most 3 arp entries */ 57 58 static struct arp_list { 59 n_long addr; 60 u_char ea[6]; 61 } arp_list[ARP_NUM] = { 62 { INADDR_BROADCAST, BA } 63 }; 64 static int arp_num = 1; 65 66 /* Local forwards */ 67 static int arpsend __P((struct iodesc *, void *, int)); 68 static int arprecv __P((struct iodesc *, void *, int)); 69 70 /* Broadcast an ARP packet, asking who has addr on interface d */ 71 u_char * 72 arpwhohas(d, addr) 73 register struct iodesc *d; 74 n_long addr; 75 { 76 register int i; 77 register struct ether_arp *ah; 78 register struct arp_list *al; 79 struct { 80 u_char header[ETHER_SIZE]; 81 struct ether_arp warp; 82 } wbuf; 83 union { 84 u_char buffer[RECV_SIZE]; 85 struct { 86 u_char header[ETHER_SIZE]; 87 struct ether_arp rarp; 88 } ru; 89 } rbuf; 90 91 #ifdef ARP_DEBUG 92 if (debug) 93 printf("arpwhohas: called for %s\n", intoa(addr)); 94 #endif 95 /* Try for cached answer first */ 96 for (i = 0, al = arp_list; i < arp_num; ++i, ++al) 97 if (addr == al->addr) 98 return (al->ea); 99 100 /* Don't overflow cache */ 101 if (arp_num > ARP_NUM - 1) 102 panic("arpwhohas: overflowed arp_list!"); 103 104 #ifdef ARP_DEBUG 105 if (debug) 106 printf("arpwhohas: not cached\n"); 107 #endif 108 ah = &wbuf.warp; 109 bzero(ah, sizeof(*ah)); 110 111 ah->arp_hrd = htons(ARPHRD_ETHER); 112 ah->arp_pro = htons(ETHERTYPE_IP); 113 ah->arp_hln = sizeof(ah->arp_sha); /* hardware address length */ 114 ah->arp_pln = sizeof(ah->arp_spa); /* protocol address length */ 115 ah->arp_op = htons(ARPOP_REQUEST); 116 MACPY(d->myea, ah->arp_sha); 117 bcopy(&d->myip, ah->arp_spa, sizeof(ah->arp_spa)); 118 bcopy(&addr, ah->arp_tpa, sizeof(ah->arp_tpa)); 119 120 /* Store ip address in cache */ 121 al->addr = addr; 122 123 (void)sendrecv(d, arpsend, ah, sizeof(*ah), arprecv, 124 ((u_char *)&rbuf.ru.rarp) - ETHER_SIZE, 125 ETHER_SIZE + sizeof(rbuf.ru.rarp)); 126 127 /* Store ethernet address in cache */ 128 MACPY(rbuf.ru.rarp.arp_sha, al->ea); 129 ++arp_num; 130 #ifdef ARP_DEBUG 131 if (debug) 132 printf("arpwhohas: cacheing %s --> %s\n", intoa(addr), ether_sprintf(al->ea)); 133 #endif 134 135 return (al->ea); 136 } 137 138 static int 139 arpsend(d, pkt, len) 140 register struct iodesc *d; 141 register void *pkt; 142 register int len; 143 { 144 #ifdef ARP_DEBUG 145 if (debug) 146 printf("arpsend: called\n"); 147 #endif 148 return (sendether(d, pkt, len, bcea, ETHERTYPE_ARP)); 149 } 150 151 /* Returns 0 if this is the packet we're waiting for else -1 (and errno == 0) */ 152 static int 153 arprecv(d, pkt, len) 154 register struct iodesc *d; 155 register void *pkt; 156 register int len; 157 { 158 register struct ether_header *eh; 159 register struct ether_arp *ah; 160 161 #ifdef ARP_DEBUG 162 if (debug) 163 printf("arprecv: called\n"); 164 #endif 165 if (len < sizeof(*eh) + sizeof(*ah)) { 166 errno = 0; 167 return (-1); 168 } 169 170 eh = (struct ether_header *)pkt; 171 172 /* Must be to us */ 173 if (bcmp(d->myea, eh->ether_dhost, 6) != 0 && 174 bcmp(bcea, eh->ether_dhost, 6) != 0) { 175 #ifdef ARP_DEBUG 176 if (debug) 177 printf("arprecv: not ours %s\n", ether_sprintf(eh->ether_dhost)); 178 #endif 179 errno = 0; 180 return (-1); 181 } 182 183 if (ntohs(eh->ether_type) != ETHERTYPE_ARP) { 184 #ifdef ARP_DEBUG 185 if (debug) 186 printf("arprecv: not arp %d\n", ntohs(eh->ether_type)); 187 #endif 188 errno = 0; 189 return (-1); 190 } 191 192 ah = (struct ether_arp *)(eh + 1); 193 HTONS(ah->arp_hrd); 194 HTONS(ah->arp_pro); 195 HTONS(ah->arp_op); 196 if (ah->arp_hrd != ARPHRD_ETHER || ah->arp_pro != ETHERTYPE_IP || 197 ah->arp_hln != sizeof(ah->arp_sha) || 198 ah->arp_pln != sizeof(ah->arp_spa) || ah->arp_op != ARPOP_REPLY) { 199 #ifdef ARP_DEBUG 200 if (debug) 201 printf("arprecv: not valid reply\n"); 202 #endif 203 errno = 0; 204 return (-1); 205 } 206 if (bcmp(&arp_list[arp_num].addr, ah->arp_spa, sizeof(long)) != 0 || 207 bcmp(&d->myip, ah->arp_tpa, sizeof(d->myip)) != 0) { 208 #ifdef ARP_DEBUG 209 if (debug) 210 printf("arprecv: already cached??\n"); 211 #endif 212 errno = 0; 213 return (-1); 214 } 215 216 return (0); 217 } 218