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 * 4. 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 56static ssize_t rarpsend(struct iodesc *, void *, size_t); 57static ssize_t rarprecv(struct iodesc *, void *, size_t, time_t); 58 59/* 60 * Ethernet (Reverse) Address Resolution Protocol (see RFC 903, and 826). 61 */ 62int 63rarp_getipaddress(sock) 64 int sock; 65{ 66 struct iodesc *d; 67 struct ether_arp *ap; 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 struct { 76 u_char header[ETHER_SIZE]; 77 struct { 78 struct ether_arp arp; 79 u_char pad[24]; /* extra space */ 80 } data; 81 } rbuf; 82 83#ifdef RARP_DEBUG 84 if (debug) 85 printf("rarp: socket=%d\n", sock); 86#endif 87 if (!(d = socktodesc(sock))) { 88 printf("rarp: bad socket. %d\n", sock); 89 return (-1); 90 } 91#ifdef RARP_DEBUG 92 if (debug) 93 printf("rarp: d=%x\n", (u_int)d); 94#endif 95 96 bzero((char*)&wbuf.data, sizeof(wbuf.data)); 97 ap = &wbuf.data.arp; 98 ap->arp_hrd = htons(ARPHRD_ETHER); 99 ap->arp_pro = htons(ETHERTYPE_IP); 100 ap->arp_hln = sizeof(ap->arp_sha); /* hardware address length */ 101 ap->arp_pln = sizeof(ap->arp_spa); /* protocol address length */ 102 ap->arp_op = htons(ARPOP_REVREQUEST); 103 bcopy(d->myea, ap->arp_sha, 6); 104 bcopy(d->myea, ap->arp_tha, 6); 105 106 if (sendrecv(d, 107 rarpsend, &wbuf.data, sizeof(wbuf.data), 108 rarprecv, &rbuf.data, sizeof(rbuf.data)) < 0) 109 { 110 printf("No response for RARP request\n"); 111 return (-1); 112 } 113 114 ap = &rbuf.data.arp; 115 bcopy(ap->arp_tpa, (char *)&myip, sizeof(myip)); 116#if 0 117 /* XXX - Can NOT assume this is our root server! */ 118 bcopy(ap->arp_spa, (char *)&rootip, sizeof(rootip)); 119#endif 120 121 /* Compute our "natural" netmask. */ 122 if (IN_CLASSA(myip.s_addr)) 123 netmask = IN_CLASSA_NET; 124 else if (IN_CLASSB(myip.s_addr)) 125 netmask = IN_CLASSB_NET; 126 else 127 netmask = IN_CLASSC_NET; 128 129 d->myip = myip; 130 return (0); 131} 132 133/* 134 * Broadcast a RARP request (i.e. who knows who I am) 135 */ 136static ssize_t 137rarpsend(d, pkt, len) 138 struct iodesc *d; 139 void *pkt; 140 size_t len; 141{ 142 143#ifdef RARP_DEBUG 144 if (debug) 145 printf("rarpsend: called\n"); 146#endif 147 148 return (sendether(d, pkt, len, bcea, ETHERTYPE_REVARP)); 149} 150 151/* 152 * Returns 0 if this is the packet we're waiting for 153 * else -1 (and errno == 0) 154 */ 155static ssize_t 156rarprecv(d, pkt, len, tleft) 157 struct iodesc *d; 158 void *pkt; 159 size_t len; 160 time_t tleft; 161{ 162 ssize_t n; 163 struct ether_arp *ap; 164 u_int16_t etype; /* host order */ 165 166#ifdef RARP_DEBUG 167 if (debug) 168 printf("rarprecv: "); 169#endif 170 171 n = readether(d, pkt, len, tleft, &etype); 172 errno = 0; /* XXX */ 173 if (n == -1 || n < sizeof(struct ether_arp)) { 174#ifdef RARP_DEBUG 175 if (debug) 176 printf("bad len=%d\n", n); 177#endif 178 return (-1); 179 } 180 181 if (etype != ETHERTYPE_REVARP) { 182#ifdef RARP_DEBUG 183 if (debug) 184 printf("bad type=0x%x\n", etype); 185#endif 186 return (-1); 187 } 188 189 ap = (struct ether_arp *)pkt; 190 if (ap->arp_hrd != htons(ARPHRD_ETHER) || 191 ap->arp_pro != htons(ETHERTYPE_IP) || 192 ap->arp_hln != sizeof(ap->arp_sha) || 193 ap->arp_pln != sizeof(ap->arp_spa) ) 194 { 195#ifdef RARP_DEBUG 196 if (debug) 197 printf("bad hrd/pro/hln/pln\n"); 198#endif 199 return (-1); 200 } 201 202 if (ap->arp_op != htons(ARPOP_REVREPLY)) { 203#ifdef RARP_DEBUG 204 if (debug) 205 printf("bad op=0x%x\n", ntohs(ap->arp_op)); 206#endif 207 return (-1); 208 } 209 210 /* Is the reply for our Ethernet address? */ 211 if (bcmp(ap->arp_tha, d->myea, 6)) { 212#ifdef RARP_DEBUG 213 if (debug) 214 printf("unwanted address\n"); 215#endif 216 return (-1); 217 } 218 219 /* We have our answer. */ 220#ifdef RARP_DEBUG 221 if (debug) 222 printf("got it\n"); 223#endif 224 return (n); 225} 226