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 36 #include <sys/param.h> 37 #include <sys/socket.h> 38 #include <net/if.h> 39 #include <netinet/in.h> 40 #include <netinet/if_ether.h> 41 42 #include <netinet/in_systm.h> 43 44 #include <string.h> 45 46 #include "stand.h" 47 #include "net.h" 48 #include "netif.h" 49 50 51 static ssize_t rarpsend(struct iodesc *, void *, size_t); 52 static ssize_t rarprecv(struct iodesc *, void **, void **, time_t, void *); 53 54 /* 55 * Ethernet (Reverse) Address Resolution Protocol (see RFC 903, and 826). 56 */ 57 int 58 rarp_getipaddress(int sock) 59 { 60 struct iodesc *d; 61 struct ether_arp *ap; 62 void *pkt; 63 struct { 64 u_char header[ETHER_SIZE]; 65 struct { 66 struct ether_arp arp; 67 u_char pad[18]; /* 60 - sizeof(arp) */ 68 } data; 69 } wbuf; 70 71 #ifdef RARP_DEBUG 72 if (debug) 73 printf("rarp: socket=%d\n", sock); 74 #endif 75 if (!(d = socktodesc(sock))) { 76 printf("rarp: bad socket. %d\n", sock); 77 return (-1); 78 } 79 #ifdef RARP_DEBUG 80 if (debug) 81 printf("rarp: d=%lx\n", (long)d); 82 #endif 83 84 bzero((char*)&wbuf.data, sizeof(wbuf.data)); 85 ap = &wbuf.data.arp; 86 ap->arp_hrd = htons(ARPHRD_ETHER); 87 ap->arp_pro = htons(ETHERTYPE_IP); 88 ap->arp_hln = sizeof(ap->arp_sha); /* hardware address length */ 89 ap->arp_pln = sizeof(ap->arp_spa); /* protocol address length */ 90 ap->arp_op = htons(ARPOP_REVREQUEST); 91 bcopy(d->myea, ap->arp_sha, 6); 92 bcopy(d->myea, ap->arp_tha, 6); 93 pkt = NULL; 94 95 if (sendrecv(d, 96 rarpsend, &wbuf.data, sizeof(wbuf.data), 97 rarprecv, &pkt, (void *)&ap, NULL) < 0) { 98 printf("No response for RARP request\n"); 99 return (-1); 100 } 101 102 bcopy(ap->arp_tpa, (char *)&myip, sizeof(myip)); 103 #if 0 104 /* XXX - Can NOT assume this is our root server! */ 105 bcopy(ap->arp_spa, (char *)&rootip, sizeof(rootip)); 106 #endif 107 free(pkt); 108 109 /* Compute our "natural" netmask. */ 110 if (IN_CLASSA(myip.s_addr)) 111 netmask = IN_CLASSA_NET; 112 else if (IN_CLASSB(myip.s_addr)) 113 netmask = IN_CLASSB_NET; 114 else 115 netmask = IN_CLASSC_NET; 116 117 d->myip = myip; 118 return (0); 119 } 120 121 /* 122 * Broadcast a RARP request (i.e. who knows who I am) 123 */ 124 static ssize_t 125 rarpsend(struct iodesc *d, void *pkt, size_t len) 126 { 127 128 #ifdef RARP_DEBUG 129 if (debug) 130 printf("rarpsend: called\n"); 131 #endif 132 133 return (sendether(d, pkt, len, bcea, ETHERTYPE_REVARP)); 134 } 135 136 /* 137 * Returns 0 if this is the packet we're waiting for 138 * else -1 (and errno == 0) 139 */ 140 static ssize_t 141 rarprecv(struct iodesc *d, void **pkt, void **payload, time_t tleft, 142 void *extra) 143 { 144 ssize_t n; 145 struct ether_arp *ap; 146 void *ptr = NULL; 147 uint16_t etype; /* host order */ 148 149 #ifdef RARP_DEBUG 150 if (debug) 151 printf("rarprecv: "); 152 #endif 153 154 n = readether(d, &ptr, (void **)&ap, tleft, &etype); 155 errno = 0; /* XXX */ 156 if (n == -1 || n < sizeof(struct ether_arp)) { 157 #ifdef RARP_DEBUG 158 if (debug) 159 printf("bad len=%zd\n", n); 160 #endif 161 free(ptr); 162 return (-1); 163 } 164 165 if (etype != ETHERTYPE_REVARP) { 166 #ifdef RARP_DEBUG 167 if (debug) 168 printf("bad type=0x%x\n", etype); 169 #endif 170 free(ptr); 171 return (-1); 172 } 173 174 if (ap->arp_hrd != htons(ARPHRD_ETHER) || 175 ap->arp_pro != htons(ETHERTYPE_IP) || 176 ap->arp_hln != sizeof(ap->arp_sha) || 177 ap->arp_pln != sizeof(ap->arp_spa) ) 178 { 179 #ifdef RARP_DEBUG 180 if (debug) 181 printf("bad hrd/pro/hln/pln\n"); 182 #endif 183 free(ptr); 184 return (-1); 185 } 186 187 if (ap->arp_op != htons(ARPOP_REVREPLY)) { 188 #ifdef RARP_DEBUG 189 if (debug) 190 printf("bad op=0x%x\n", ntohs(ap->arp_op)); 191 #endif 192 free(ptr); 193 return (-1); 194 } 195 196 /* Is the reply for our Ethernet address? */ 197 if (bcmp(ap->arp_tha, d->myea, 6)) { 198 #ifdef RARP_DEBUG 199 if (debug) 200 printf("unwanted address\n"); 201 #endif 202 free(ptr); 203 return (-1); 204 } 205 206 /* We have our answer. */ 207 #ifdef RARP_DEBUG 208 if (debug) 209 printf("got it\n"); 210 #endif 211 *pkt = ptr; 212 *payload = ap; 213 return (n); 214 } 215