rarp.c revision 1.24
1 /* $NetBSD: rarp.c,v 1.24 2005/06/13 12:11:07 junyoung 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 <net/if_ether.h> 45 #include <netinet/in.h> 46 47 #include <netinet/in_systm.h> 48 49 #ifdef _STANDALONE 50 #include <lib/libkern/libkern.h> 51 #else 52 #include <string.h> 53 #endif 54 55 #include "stand.h" 56 #include "net.h" 57 58 59 /* 60 * Ethernet Address Resolution Protocol. 61 * 62 * See RFC 826 for protocol description. Structure below is adapted 63 * to resolving internet addresses. Field names used correspond to 64 * RFC 826. 65 */ 66 struct ether_arp { 67 struct arphdr ea_hdr; /* fixed-size header */ 68 u_int8_t arp_sha[ETHER_ADDR_LEN]; /* sender hardware address */ 69 u_int8_t arp_spa[4]; /* sender protocol address */ 70 u_int8_t arp_tha[ETHER_ADDR_LEN]; /* target hardware address */ 71 u_int8_t arp_tpa[4]; /* target protocol address */ 72 }; 73 #define arp_hrd ea_hdr.ar_hrd 74 #define arp_pro ea_hdr.ar_pro 75 #define arp_hln ea_hdr.ar_hln 76 #define arp_pln ea_hdr.ar_pln 77 #define arp_op ea_hdr.ar_op 78 79 static ssize_t rarpsend __P((struct iodesc *, void *, size_t)); 80 static ssize_t rarprecv __P((struct iodesc *, void *, size_t, time_t)); 81 82 /* 83 * Ethernet (Reverse) Address Resolution Protocol (see RFC 903, and 826). 84 */ 85 int 86 rarp_getipaddress(sock) 87 int sock; 88 { 89 struct iodesc *d; 90 struct ether_arp *ap; 91 struct { 92 u_char header[ETHER_SIZE]; 93 struct { 94 struct ether_arp arp; 95 u_char pad[18]; /* 60 - sizeof(arp) */ 96 } data; 97 } wbuf; 98 struct { 99 u_char header[ETHER_SIZE]; 100 struct { 101 struct ether_arp arp; 102 u_char pad[24]; /* extra space */ 103 } data; 104 } rbuf; 105 106 #ifdef RARP_DEBUG 107 if (debug) 108 printf("rarp: socket=%d\n", sock); 109 #endif 110 if (!(d = socktodesc(sock))) { 111 printf("rarp: bad socket. %d\n", sock); 112 return (-1); 113 } 114 #ifdef RARP_DEBUG 115 if (debug) 116 printf("rarp: d=%lx\n", (u_long)d); 117 #endif 118 119 bzero((char*)&wbuf.data, sizeof(wbuf.data)); 120 ap = &wbuf.data.arp; 121 ap->arp_hrd = htons(ARPHRD_ETHER); 122 ap->arp_pro = htons(ETHERTYPE_IP); 123 ap->arp_hln = sizeof(ap->arp_sha); /* hardware address length */ 124 ap->arp_pln = sizeof(ap->arp_spa); /* protocol address length */ 125 ap->arp_op = htons(ARPOP_REVREQUEST); 126 bcopy(d->myea, ap->arp_sha, 6); 127 bcopy(d->myea, ap->arp_tha, 6); 128 129 if (sendrecv(d, 130 rarpsend, &wbuf.data, sizeof(wbuf.data), 131 rarprecv, &rbuf.data, sizeof(rbuf.data)) < 0) 132 { 133 printf("No response for RARP request\n"); 134 return (-1); 135 } 136 137 ap = &rbuf.data.arp; 138 bcopy(ap->arp_tpa, (char *)&myip, sizeof(myip)); 139 #if 0 140 /* XXX - Can NOT assume this is our root server! */ 141 bcopy(ap->arp_spa, (char *)&rootip, sizeof(rootip)); 142 #endif 143 144 /* Compute our "natural" netmask. */ 145 if (IN_CLASSA(myip.s_addr)) 146 netmask = IN_CLASSA_NET; 147 else if (IN_CLASSB(myip.s_addr)) 148 netmask = IN_CLASSB_NET; 149 else 150 netmask = IN_CLASSC_NET; 151 152 d->myip = myip; 153 return (0); 154 } 155 156 /* 157 * Broadcast a RARP request (i.e. who knows who I am) 158 */ 159 static ssize_t 160 rarpsend(d, pkt, len) 161 struct iodesc *d; 162 void *pkt; 163 size_t len; 164 { 165 166 #ifdef RARP_DEBUG 167 if (debug) 168 printf("rarpsend: called\n"); 169 #endif 170 171 return (sendether(d, pkt, len, bcea, ETHERTYPE_REVARP)); 172 } 173 174 /* 175 * Returns 0 if this is the packet we're waiting for 176 * else -1 (and errno == 0) 177 */ 178 static ssize_t 179 rarprecv(d, pkt, len, tleft) 180 struct iodesc *d; 181 void *pkt; 182 size_t len; 183 time_t tleft; 184 { 185 ssize_t n; 186 struct ether_arp *ap; 187 u_int16_t etype; /* host order */ 188 189 #ifdef RARP_DEBUG 190 if (debug) 191 printf("rarprecv: "); 192 #endif 193 194 n = readether(d, pkt, len, tleft, &etype); 195 errno = 0; /* XXX */ 196 if (n == -1 || (size_t)n < sizeof(struct ether_arp)) { 197 #ifdef RARP_DEBUG 198 if (debug) 199 printf("bad len=%d\n", n); 200 #endif 201 return (-1); 202 } 203 204 if (etype != ETHERTYPE_REVARP) { 205 #ifdef RARP_DEBUG 206 if (debug) 207 printf("bad type=0x%x\n", etype); 208 #endif 209 return (-1); 210 } 211 212 ap = (struct ether_arp *)pkt; 213 if (ap->arp_hrd != htons(ARPHRD_ETHER) || 214 ap->arp_pro != htons(ETHERTYPE_IP) || 215 ap->arp_hln != sizeof(ap->arp_sha) || 216 ap->arp_pln != sizeof(ap->arp_spa) ) 217 { 218 #ifdef RARP_DEBUG 219 if (debug) 220 printf("bad hrd/pro/hln/pln\n"); 221 #endif 222 return (-1); 223 } 224 225 if (ap->arp_op != htons(ARPOP_REVREPLY)) { 226 #ifdef RARP_DEBUG 227 if (debug) 228 printf("bad op=0x%x\n", ntohs(ap->arp_op)); 229 #endif 230 return (-1); 231 } 232 233 /* Is the reply for our Ethernet address? */ 234 if (memcmp(ap->arp_tha, d->myea, 6)) { 235 #ifdef RARP_DEBUG 236 if (debug) 237 printf("unwanted address\n"); 238 #endif 239 return (-1); 240 } 241 242 /* We have our answer. */ 243 #ifdef RARP_DEBUG 244 if (debug) 245 printf("got it\n"); 246 #endif 247 return (n); 248 } 249
Indexes created Wed Sep 24 02:09:48 GMT 2025