rarp.c revision 1.15
1 /* $NetBSD: rarp.c,v 1.15 1997/06/26 19:11:50 drochner Exp $ */ 2 3 /* 4 * Copyright (c) 1992 Regents of the University of California. 5 * All rights reserved. 6 * 7 * This software was developed by the Computer Systems Engineering group 8 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and 9 * contributed to Berkeley. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the University of 22 * California, Lawrence Berkeley Laboratory and its contributors. 23 * 4. Neither the name of the University nor the names of its contributors 24 * may be used to endorse or promote products derived from this software 25 * without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 37 * SUCH DAMAGE. 38 * 39 * @(#) Header: arp.c,v 1.5 93/07/15 05:52:26 leres Exp (LBL) 40 */ 41 #include <sys/param.h> 42 #include <sys/socket.h> 43 #include <net/if.h> 44 #include <netinet/in.h> 45 46 #include <netinet/in_systm.h> 47 48 #ifdef _STANDALONE 49 #include <lib/libkern/libkern.h> 50 #else 51 #include <string.h> 52 #endif 53 54 #include "if_ether.h" 55 #include "stand.h" 56 #include "net.h" 57 #include "netif.h" 58 59 static ssize_t rarpsend __P((struct iodesc *, void *, size_t)); 60 static ssize_t rarprecv __P((struct iodesc *, void *, size_t, time_t)); 61 62 /* 63 * Ethernet (Reverse) Address Resolution Protocol (see RFC 903, and 826). 64 */ 65 int 66 rarp_getipaddress(sock) 67 int sock; 68 { 69 struct iodesc *d; 70 register struct ether_arp *ap; 71 struct { 72 u_char header[ETHER_SIZE]; 73 struct { 74 struct ether_arp arp; 75 u_char pad[18]; /* 60 - sizeof(arp) */ 76 } data; 77 } wbuf; 78 struct { 79 u_char header[ETHER_SIZE]; 80 struct { 81 struct ether_arp arp; 82 u_char pad[24]; /* extra space */ 83 } data; 84 } rbuf; 85 86 #ifdef RARP_DEBUG 87 if (debug) 88 printf("rarp: socket=%d\n", sock); 89 #endif 90 if (!(d = socktodesc(sock))) { 91 printf("rarp: bad socket. %d\n", sock); 92 return (-1); 93 } 94 #ifdef RARP_DEBUG 95 if (debug) 96 printf("rarp: d=%x\n", (u_int)d); 97 #endif 98 99 bzero((char*)&wbuf.data, sizeof(wbuf.data)); 100 ap = &wbuf.data.arp; 101 ap->arp_hrd = htons(ARPHRD_ETHER); 102 ap->arp_pro = htons(ETHERTYPE_IP); 103 ap->arp_hln = sizeof(ap->arp_sha); /* hardware address length */ 104 ap->arp_pln = sizeof(ap->arp_spa); /* protocol address length */ 105 ap->arp_op = htons(ARPOP_REVREQUEST); 106 bcopy(d->myea, ap->arp_sha, 6); 107 bcopy(d->myea, ap->arp_tha, 6); 108 109 if (sendrecv(d, 110 rarpsend, &wbuf.data, sizeof(wbuf.data), 111 rarprecv, &rbuf.data, sizeof(rbuf.data)) < 0) 112 { 113 printf("No response for RARP request\n"); 114 return (-1); 115 } 116 117 ap = &rbuf.data.arp; 118 bcopy(ap->arp_tpa, (char *)&myip, sizeof(myip)); 119 #if 0 120 /* XXX - Can NOT assume this is our root server! */ 121 bcopy(ap->arp_spa, (char *)&rootip, sizeof(rootip)); 122 #endif 123 124 /* Compute our "natural" netmask. */ 125 if (IN_CLASSA(myip.s_addr)) 126 netmask = IN_CLASSA_NET; 127 else if (IN_CLASSB(myip.s_addr)) 128 netmask = IN_CLASSB_NET; 129 else 130 netmask = IN_CLASSC_NET; 131 132 d->myip = myip; 133 return (0); 134 } 135 136 /* 137 * Broadcast a RARP request (i.e. who knows who I am) 138 */ 139 static ssize_t 140 rarpsend(d, pkt, len) 141 register struct iodesc *d; 142 register void *pkt; 143 register size_t len; 144 { 145 146 #ifdef RARP_DEBUG 147 if (debug) 148 printf("rarpsend: called\n"); 149 #endif 150 151 return (sendether(d, pkt, len, bcea, ETHERTYPE_REVARP)); 152 } 153 154 /* 155 * Returns 0 if this is the packet we're waiting for 156 * else -1 (and errno == 0) 157 */ 158 static ssize_t 159 rarprecv(d, pkt, len, tleft) 160 register struct iodesc *d; 161 register void *pkt; 162 register size_t len; 163 time_t tleft; 164 { 165 register ssize_t n; 166 register struct ether_arp *ap; 167 u_int16_t etype; /* host order */ 168 169 #ifdef RARP_DEBUG 170 if (debug) 171 printf("rarprecv: "); 172 #endif 173 174 n = readether(d, pkt, len, tleft, &etype); 175 errno = 0; /* XXX */ 176 if (n == -1 || n < sizeof(struct ether_arp)) { 177 #ifdef RARP_DEBUG 178 if (debug) 179 printf("bad len=%d\n", n); 180 #endif 181 return (-1); 182 } 183 184 if (etype != ETHERTYPE_REVARP) { 185 #ifdef RARP_DEBUG 186 if (debug) 187 printf("bad type=0x%x\n", etype); 188 #endif 189 return (-1); 190 } 191 192 ap = (struct ether_arp *)pkt; 193 if (ap->arp_hrd != htons(ARPHRD_ETHER) || 194 ap->arp_pro != htons(ETHERTYPE_IP) || 195 ap->arp_hln != sizeof(ap->arp_sha) || 196 ap->arp_pln != sizeof(ap->arp_spa) ) 197 { 198 #ifdef RARP_DEBUG 199 if (debug) 200 printf("bad hrd/pro/hln/pln\n"); 201 #endif 202 return (-1); 203 } 204 205 if (ap->arp_op != htons(ARPOP_REVREPLY)) { 206 #ifdef RARP_DEBUG 207 if (debug) 208 printf("bad op=0x%x\n", ntohs(ap->arp_op)); 209 #endif 210 return (-1); 211 } 212 213 /* Is the reply for our Ethernet address? */ 214 if (bcmp(ap->arp_tha, d->myea, 6)) { 215 #ifdef RARP_DEBUG 216 if (debug) 217 printf("unwanted address\n"); 218 #endif 219 return (-1); 220 } 221 222 /* We have our answer. */ 223 #ifdef RARP_DEBUG 224 if (debug) 225 printf("got it\n"); 226 #endif 227 return (n); 228 } 229
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