1 /* $NetBSD: rarp.c,v 1.16 1997/07/07 15:52:52 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. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * @(#) Header: arp.c,v 1.5 93/07/15 05:52:26 leres Exp (LBL) 36 */ 37 38 #include <sys/cdefs.h> 39 __FBSDID("$FreeBSD$"); 40 41 #include <sys/param.h> 42 #include <sys/socket.h> 43 #include <net/if.h> 44 #include <netinet/in.h> 45 #include <netinet/if_ether.h> 46 47 #include <netinet/in_systm.h> 48 49 #include <string.h> 50 51 #include "stand.h" 52 #include "net.h" 53 #include "netif.h" 54 55 56 static ssize_t rarpsend(struct iodesc *, void *, size_t); 57 static ssize_t rarprecv(struct iodesc *, void **, void **, time_t); 58 59 /* 60 * Ethernet (Reverse) Address Resolution Protocol (see RFC 903, and 826). 61 */ 62 int 63 rarp_getipaddress(int sock) 64 { 65 struct iodesc *d; 66 struct ether_arp *ap; 67 void *pkt; 68 struct { 69 u_char header[ETHER_SIZE]; 70 struct { 71 struct ether_arp arp; 72 u_char pad[18]; /* 60 - sizeof(arp) */ 73 } data; 74 } wbuf; 75 76 #ifdef RARP_DEBUG 77 if (debug) 78 printf("rarp: socket=%d\n", sock); 79 #endif 80 if (!(d = socktodesc(sock))) { 81 printf("rarp: bad socket. %d\n", sock); 82 return (-1); 83 } 84 #ifdef RARP_DEBUG 85 if (debug) 86 printf("rarp: d=%x\n", (u_int)d); 87 #endif 88 89 bzero((char*)&wbuf.data, sizeof(wbuf.data)); 90 ap = &wbuf.data.arp; 91 ap->arp_hrd = htons(ARPHRD_ETHER); 92 ap->arp_pro = htons(ETHERTYPE_IP); 93 ap->arp_hln = sizeof(ap->arp_sha); /* hardware address length */ 94 ap->arp_pln = sizeof(ap->arp_spa); /* protocol address length */ 95 ap->arp_op = htons(ARPOP_REVREQUEST); 96 bcopy(d->myea, ap->arp_sha, 6); 97 bcopy(d->myea, ap->arp_tha, 6); 98 pkt = NULL; 99 100 if (sendrecv(d, 101 rarpsend, &wbuf.data, sizeof(wbuf.data), 102 rarprecv, &pkt, (void *)&ap) < 0) { 103 printf("No response for RARP request\n"); 104 return (-1); 105 } 106 107 bcopy(ap->arp_tpa, (char *)&myip, sizeof(myip)); 108 #if 0 109 /* XXX - Can NOT assume this is our root server! */ 110 bcopy(ap->arp_spa, (char *)&rootip, sizeof(rootip)); 111 #endif 112 free(pkt); 113 114 /* Compute our "natural" netmask. */ 115 if (IN_CLASSA(myip.s_addr)) 116 netmask = IN_CLASSA_NET; 117 else if (IN_CLASSB(myip.s_addr)) 118 netmask = IN_CLASSB_NET; 119 else 120 netmask = IN_CLASSC_NET; 121 122 d->myip = myip; 123 return (0); 124 } 125 126 /* 127 * Broadcast a RARP request (i.e. who knows who I am) 128 */ 129 static ssize_t 130 rarpsend(struct iodesc *d, void *pkt, size_t len) 131 { 132 133 #ifdef RARP_DEBUG 134 if (debug) 135 printf("rarpsend: called\n"); 136 #endif 137 138 return (sendether(d, pkt, len, bcea, ETHERTYPE_REVARP)); 139 } 140 141 /* 142 * Returns 0 if this is the packet we're waiting for 143 * else -1 (and errno == 0) 144 */ 145 static ssize_t 146 rarprecv(struct iodesc *d, void **pkt, void **payload, time_t tleft) 147 { 148 ssize_t n; 149 struct ether_arp *ap; 150 void *ptr = NULL; 151 uint16_t etype; /* host order */ 152 153 #ifdef RARP_DEBUG 154 if (debug) 155 printf("rarprecv: "); 156 #endif 157 158 n = readether(d, &ptr, (void **)&ap, tleft, &etype); 159 errno = 0; /* XXX */ 160 if (n == -1 || n < sizeof(struct ether_arp)) { 161 #ifdef RARP_DEBUG 162 if (debug) 163 printf("bad len=%d\n", n); 164 #endif 165 free(ptr); 166 return (-1); 167 } 168 169 if (etype != ETHERTYPE_REVARP) { 170 #ifdef RARP_DEBUG 171 if (debug) 172 printf("bad type=0x%x\n", etype); 173 #endif 174 free(ptr); 175 return (-1); 176 } 177 178 if (ap->arp_hrd != htons(ARPHRD_ETHER) || 179 ap->arp_pro != htons(ETHERTYPE_IP) || 180 ap->arp_hln != sizeof(ap->arp_sha) || 181 ap->arp_pln != sizeof(ap->arp_spa) ) 182 { 183 #ifdef RARP_DEBUG 184 if (debug) 185 printf("bad hrd/pro/hln/pln\n"); 186 #endif 187 free(ptr); 188 return (-1); 189 } 190 191 if (ap->arp_op != htons(ARPOP_REVREPLY)) { 192 #ifdef RARP_DEBUG 193 if (debug) 194 printf("bad op=0x%x\n", ntohs(ap->arp_op)); 195 #endif 196 free(ptr); 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 free(ptr); 207 return (-1); 208 } 209 210 /* We have our answer. */ 211 #ifdef RARP_DEBUG 212 if (debug) 213 printf("got it\n"); 214 #endif 215 *pkt = ptr; 216 *payload = ap; 217 return (n); 218 } 219