1 /* $OpenBSD: rarp.c,v 1.5 1996/12/08 15:15:55 niklas Exp $ */ 2 /* $NetBSD: rarp.c,v 1.13 1996/10/13 02:29:05 christos Exp $ */ 3 4 /* 5 * Copyright (c) 1992 Regents of the University of California. 6 * All rights reserved. 7 * 8 * This software was developed by the Computer Systems Engineering group 9 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and 10 * contributed to Berkeley. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. All advertising materials mentioning features or use of this software 21 * must display the following acknowledgement: 22 * This product includes software developed by the University of 23 * California, Lawrence Berkeley Laboratory and its contributors. 24 * 4. Neither the name of the University nor the names of its contributors 25 * may be used to endorse or promote products derived from this software 26 * without specific prior written permission. 27 * 28 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 29 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 30 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 31 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 32 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 37 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 38 * SUCH DAMAGE. 39 * 40 * @(#) Header: arp.c,v 1.5 93/07/15 05:52:26 leres Exp (LBL) 41 */ 42 #include <sys/param.h> 43 #include <sys/socket.h> 44 #include <net/if.h> 45 #include <netinet/in.h> 46 47 #include <netinet/if_ether.h> 48 #include <netinet/in_systm.h> 49 50 #include "stand.h" 51 #include "net.h" 52 #include "netif.h" 53 54 static ssize_t rarpsend __P((struct iodesc *, void *, size_t)); 55 static ssize_t rarprecv __P((struct iodesc *, void *, size_t, time_t)); 56 57 /* 58 * Ethernet (Reverse) Address Resolution Protocol (see RFC 903, and 826). 59 */ 60 int 61 rarp_getipaddress(sock) 62 int sock; 63 { 64 struct iodesc *d; 65 register struct ether_arp *ap; 66 struct { 67 u_char header[ETHER_SIZE]; 68 struct { 69 struct ether_arp arp; 70 u_char pad[18]; /* 60 - sizeof(arp) */ 71 } data; 72 } wbuf; 73 struct { 74 u_char header[ETHER_SIZE]; 75 struct { 76 struct ether_arp arp; 77 u_char pad[24]; /* extra space */ 78 } data; 79 } rbuf; 80 81 #ifdef RARP_DEBUG 82 if (debug) 83 printf("rarp: socket=%d\n", sock); 84 #endif 85 if (!(d = socktodesc(sock))) { 86 printf("rarp: bad socket. %d\n", sock); 87 return (-1); 88 } 89 #ifdef RARP_DEBUG 90 if (debug) 91 printf("rarp: d=%x\n", (u_int)d); 92 #endif 93 94 bzero((char*)&wbuf.data, sizeof(wbuf.data)); 95 ap = &wbuf.data.arp; 96 ap->arp_hrd = htons(ARPHRD_ETHER); 97 ap->arp_pro = htons(ETHERTYPE_IP); 98 ap->arp_hln = sizeof(ap->arp_sha); /* hardware address length */ 99 ap->arp_pln = sizeof(ap->arp_spa); /* protocol address length */ 100 ap->arp_op = htons(ARPOP_REVREQUEST); 101 bcopy(d->myea, ap->arp_sha, 6); 102 bcopy(d->myea, ap->arp_tha, 6); 103 104 if (sendrecv(d, 105 rarpsend, &wbuf.data, sizeof(wbuf.data), 106 rarprecv, &rbuf.data, sizeof(rbuf.data)) < 0) 107 { 108 printf("No response for RARP request\n"); 109 return (-1); 110 } 111 112 ap = &rbuf.data.arp; 113 bcopy(ap->arp_tpa, (char *)&myip, sizeof(myip)); 114 #if 0 115 /* XXX - Can NOT assume this is our root server! */ 116 bcopy(ap->arp_spa, (char *)&rootip, sizeof(rootip)); 117 #endif 118 119 /* Compute our "natural" netmask. */ 120 if (IN_CLASSA(myip.s_addr)) 121 netmask = IN_CLASSA_NET; 122 else if (IN_CLASSB(myip.s_addr)) 123 netmask = IN_CLASSB_NET; 124 else 125 netmask = IN_CLASSC_NET; 126 127 d->myip = myip; 128 return (0); 129 } 130 131 /* 132 * Broadcast a RARP request (i.e. who knows who I am) 133 */ 134 static ssize_t 135 rarpsend(d, pkt, len) 136 register struct iodesc *d; 137 register void *pkt; 138 register size_t len; 139 { 140 141 #ifdef RARP_DEBUG 142 if (debug) 143 printf("rarpsend: called\n"); 144 #endif 145 146 return (sendether(d, pkt, len, bcea, ETHERTYPE_REVARP)); 147 } 148 149 /* 150 * Returns 0 if this is the packet we're waiting for 151 * else -1 (and errno == 0) 152 */ 153 static ssize_t 154 rarprecv(d, pkt, len, tleft) 155 register struct iodesc *d; 156 register void *pkt; 157 register size_t len; 158 time_t tleft; 159 { 160 register ssize_t n; 161 register struct ether_arp *ap; 162 u_int16_t etype; /* host order */ 163 164 #ifdef RARP_DEBUG 165 if (debug) 166 printf("rarprecv: "); 167 #endif 168 169 n = readether(d, pkt, len, tleft, &etype); 170 errno = 0; /* XXX */ 171 if (n == -1 || n < sizeof(struct ether_arp)) { 172 #ifdef RARP_DEBUG 173 if (debug) 174 printf("bad len=%d\n", n); 175 #endif 176 return (-1); 177 } 178 179 if (etype != ETHERTYPE_REVARP) { 180 #ifdef RARP_DEBUG 181 if (debug) 182 printf("bad type=0x%x\n", etype); 183 #endif 184 return (-1); 185 } 186 187 ap = (struct ether_arp *)pkt; 188 if (ap->arp_hrd != htons(ARPHRD_ETHER) || 189 ap->arp_pro != htons(ETHERTYPE_IP) || 190 ap->arp_hln != sizeof(ap->arp_sha) || 191 ap->arp_pln != sizeof(ap->arp_spa) ) 192 { 193 #ifdef RARP_DEBUG 194 if (debug) 195 printf("bad hrd/pro/hln/pln\n"); 196 #endif 197 return (-1); 198 } 199 200 if (ap->arp_op != htons(ARPOP_REVREPLY)) { 201 #ifdef RARP_DEBUG 202 if (debug) 203 printf("bad op=0x%x\n", ntohs(ap->arp_op)); 204 #endif 205 return (-1); 206 } 207 208 /* Is the reply for our Ethernet address? */ 209 if (bcmp(ap->arp_tha, d->myea, 6)) { 210 #ifdef RARP_DEBUG 211 if (debug) 212 printf("unwanted address\n"); 213 #endif 214 return (-1); 215 } 216 217 /* We have our answer. */ 218 #ifdef RARP_DEBUG 219 if (debug) 220 printf("got it\n"); 221 #endif 222 return (n); 223 } 224