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 #include <sys/param.h> 40 #include <sys/socket.h> 41 #include <net/if.h> 42 #include <netinet/in.h> 43 #include <netinet/if_ether.h> 44 45 #include <netinet/in_systm.h> 46 47 #include <string.h> 48 49 #include "stand.h" 50 #include "net.h" 51 #include "netif.h" 52 53 54 static ssize_t rarpsend(struct iodesc *, void *, size_t); 55 static ssize_t rarprecv(struct iodesc *, void **, void **, time_t, void *); 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 void *pkt; 66 struct { 67 u_char header[ETHER_SIZE]; 68 struct { 69 struct ether_arp arp; 70 u_char pad[18]; /* 60 - sizeof(arp) */ 71 } data; 72 } wbuf; 73 74 #ifdef RARP_DEBUG 75 if (debug) 76 printf("rarp: socket=%d\n", sock); 77 #endif 78 if (!(d = socktodesc(sock))) { 79 printf("rarp: bad socket. %d\n", sock); 80 return (-1); 81 } 82 #ifdef RARP_DEBUG 83 if (debug) 84 printf("rarp: d=%lx\n", (long)d); 85 #endif 86 87 bzero((char*)&wbuf.data, sizeof(wbuf.data)); 88 ap = &wbuf.data.arp; 89 ap->arp_hrd = htons(ARPHRD_ETHER); 90 ap->arp_pro = htons(ETHERTYPE_IP); 91 ap->arp_hln = sizeof(ap->arp_sha); /* hardware address length */ 92 ap->arp_pln = sizeof(ap->arp_spa); /* protocol address length */ 93 ap->arp_op = htons(ARPOP_REVREQUEST); 94 bcopy(d->myea, ap->arp_sha, 6); 95 bcopy(d->myea, ap->arp_tha, 6); 96 pkt = NULL; 97 98 if (sendrecv(d, 99 rarpsend, &wbuf.data, sizeof(wbuf.data), 100 rarprecv, &pkt, (void *)&ap, NULL) < 0) { 101 printf("No response for RARP request\n"); 102 return (-1); 103 } 104 105 bcopy(ap->arp_tpa, (char *)&myip, sizeof(myip)); 106 #if 0 107 /* XXX - Can NOT assume this is our root server! */ 108 bcopy(ap->arp_spa, (char *)&rootip, sizeof(rootip)); 109 #endif 110 free(pkt); 111 112 /* Compute our "natural" netmask. */ 113 if (IN_CLASSA(myip.s_addr)) 114 netmask = IN_CLASSA_NET; 115 else if (IN_CLASSB(myip.s_addr)) 116 netmask = IN_CLASSB_NET; 117 else 118 netmask = IN_CLASSC_NET; 119 120 d->myip = myip; 121 return (0); 122 } 123 124 /* 125 * Broadcast a RARP request (i.e. who knows who I am) 126 */ 127 static ssize_t 128 rarpsend(struct iodesc *d, void *pkt, size_t len) 129 { 130 131 #ifdef RARP_DEBUG 132 if (debug) 133 printf("rarpsend: called\n"); 134 #endif 135 136 return (sendether(d, pkt, len, bcea, ETHERTYPE_REVARP)); 137 } 138 139 /* 140 * Returns 0 if this is the packet we're waiting for 141 * else -1 (and errno == 0) 142 */ 143 static ssize_t 144 rarprecv(struct iodesc *d, void **pkt, void **payload, time_t tleft, 145 void *extra) 146 { 147 ssize_t n; 148 struct ether_arp *ap; 149 void *ptr = NULL; 150 uint16_t etype; /* host order */ 151 152 #ifdef RARP_DEBUG 153 if (debug) 154 printf("rarprecv: "); 155 #endif 156 157 n = readether(d, &ptr, (void **)&ap, tleft, &etype); 158 errno = 0; /* XXX */ 159 if (n == -1 || n < sizeof(struct ether_arp)) { 160 #ifdef RARP_DEBUG 161 if (debug) 162 printf("bad len=%zd\n", n); 163 #endif 164 free(ptr); 165 return (-1); 166 } 167 168 if (etype != ETHERTYPE_REVARP) { 169 #ifdef RARP_DEBUG 170 if (debug) 171 printf("bad type=0x%x\n", etype); 172 #endif 173 free(ptr); 174 return (-1); 175 } 176 177 if (ap->arp_hrd != htons(ARPHRD_ETHER) || 178 ap->arp_pro != htons(ETHERTYPE_IP) || 179 ap->arp_hln != sizeof(ap->arp_sha) || 180 ap->arp_pln != sizeof(ap->arp_spa) ) 181 { 182 #ifdef RARP_DEBUG 183 if (debug) 184 printf("bad hrd/pro/hln/pln\n"); 185 #endif 186 free(ptr); 187 return (-1); 188 } 189 190 if (ap->arp_op != htons(ARPOP_REVREPLY)) { 191 #ifdef RARP_DEBUG 192 if (debug) 193 printf("bad op=0x%x\n", ntohs(ap->arp_op)); 194 #endif 195 free(ptr); 196 return (-1); 197 } 198 199 /* Is the reply for our Ethernet address? */ 200 if (bcmp(ap->arp_tha, d->myea, 6)) { 201 #ifdef RARP_DEBUG 202 if (debug) 203 printf("unwanted address\n"); 204 #endif 205 free(ptr); 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 *pkt = ptr; 215 *payload = ap; 216 return (n); 217 } 218