1 /* $OpenBSD: rarp.c,v 1.10 2003/08/11 06:23:09 deraadt 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(struct iodesc *, void *, size_t); 55 static ssize_t rarprecv(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(int sock) 62 { 63 struct iodesc *d; 64 struct ether_arp *ap; 65 struct { 66 u_char header[ETHER_SIZE]; 67 struct { 68 struct ether_arp arp; 69 u_char pad[18]; /* 60 - sizeof(arp) */ 70 } data; 71 } wbuf; 72 struct { 73 u_char header[ETHER_SIZE]; 74 struct { 75 struct ether_arp arp; 76 u_char pad[24]; /* extra space */ 77 } data; 78 } rbuf; 79 80 #ifdef RARP_DEBUG 81 if (debug) 82 printf("rarp: socket=%d\n", sock); 83 #endif 84 if (!(d = socktodesc(sock))) { 85 printf("rarp: bad socket. %d\n", sock); 86 return (-1); 87 } 88 #ifdef RARP_DEBUG 89 if (debug) 90 printf("rarp: d=%x\n", (u_int)d); 91 #endif 92 93 bzero((char *)&wbuf.data, sizeof(wbuf.data)); 94 ap = &wbuf.data.arp; 95 ap->arp_hrd = htons(ARPHRD_ETHER); 96 ap->arp_pro = htons(ETHERTYPE_IP); 97 ap->arp_hln = sizeof(ap->arp_sha); /* hardware address length */ 98 ap->arp_pln = sizeof(ap->arp_spa); /* protocol address length */ 99 ap->arp_op = htons(ARPOP_REVREQUEST); 100 bcopy(d->myea, ap->arp_sha, 6); 101 bcopy(d->myea, ap->arp_tha, 6); 102 103 if (sendrecv(d, 104 rarpsend, &wbuf.data, sizeof(wbuf.data), 105 rarprecv, &rbuf.data, sizeof(rbuf.data)) < 0) 106 { 107 printf("No response for RARP request\n"); 108 return (-1); 109 } 110 111 ap = &rbuf.data.arp; 112 bcopy(ap->arp_tpa, (char *)&myip, sizeof(myip)); 113 #if 0 114 /* XXX - Can NOT assume this is our root server! */ 115 bcopy(ap->arp_spa, (char *)&rootip, sizeof(rootip)); 116 #endif 117 118 /* Compute our "natural" netmask. */ 119 if (IN_CLASSA(myip.s_addr)) 120 netmask = IN_CLASSA_NET; 121 else if (IN_CLASSB(myip.s_addr)) 122 netmask = IN_CLASSB_NET; 123 else 124 netmask = IN_CLASSC_NET; 125 126 d->myip = myip; 127 return (0); 128 } 129 130 /* 131 * Broadcast a RARP request (i.e. who knows who I am) 132 */ 133 static ssize_t 134 rarpsend(struct iodesc *d, void *pkt, size_t len) 135 { 136 137 #ifdef RARP_DEBUG 138 if (debug) 139 printf("rarpsend: called\n"); 140 #endif 141 142 return (sendether(d, pkt, len, bcea, ETHERTYPE_REVARP)); 143 } 144 145 /* 146 * Returns 0 if this is the packet we're waiting for 147 * else -1 (and errno == 0) 148 */ 149 static ssize_t 150 rarprecv(struct iodesc *d, void *pkt, size_t len, time_t tleft) 151 { 152 ssize_t n; 153 struct ether_arp *ap; 154 u_int16_t etype; /* host order */ 155 156 #ifdef RARP_DEBUG 157 if (debug) 158 printf("rarprecv: "); 159 #endif 160 161 n = readether(d, pkt, len, tleft, &etype); 162 errno = 0; /* XXX */ 163 if (n < 0 || (size_t)n < sizeof(struct ether_arp)) { 164 #ifdef RARP_DEBUG 165 if (debug) 166 printf("bad len=%d\n", n); 167 #endif 168 return (-1); 169 } 170 171 if (etype != ETHERTYPE_REVARP) { 172 #ifdef RARP_DEBUG 173 if (debug) 174 printf("bad type=0x%x\n", etype); 175 #endif 176 return (-1); 177 } 178 179 ap = (struct ether_arp *)pkt; 180 if (ap->arp_hrd != htons(ARPHRD_ETHER) || 181 ap->arp_pro != htons(ETHERTYPE_IP) || 182 ap->arp_hln != sizeof(ap->arp_sha) || 183 ap->arp_pln != sizeof(ap->arp_spa) ) 184 { 185 #ifdef RARP_DEBUG 186 if (debug) 187 printf("bad hrd/pro/hln/pln\n"); 188 #endif 189 return (-1); 190 } 191 192 if (ap->arp_op != htons(ARPOP_REVREPLY)) { 193 #ifdef RARP_DEBUG 194 if (debug) 195 printf("bad op=0x%x\n", ntohs(ap->arp_op)); 196 #endif 197 return (-1); 198 } 199 200 /* Is the reply for our Ethernet address? */ 201 if (bcmp(ap->arp_tha, d->myea, 6)) { 202 #ifdef RARP_DEBUG 203 if (debug) 204 printf("unwanted address\n"); 205 #endif 206 return (-1); 207 } 208 209 /* We have our answer. */ 210 #ifdef RARP_DEBUG 211 if (debug) 212 printf("got it\n"); 213 #endif 214 return (n); 215 } 216