1 /* $NetBSD: rarp.c,v 1.5 1995/02/20 11:04:16 mycroft 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 <netinet/in.h> 45 46 #include <netinet/if_ether.h> 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 static size_t rarpsend __P((struct iodesc *, void *, size_t)); 56 static size_t rarprecv __P((struct iodesc *, void *, size_t, time_t)); 57 58 /* 59 * Ethernet (Reverse) Address Resolution Protocol (see RFC 903, and 826). 60 */ 61 n_long 62 rarp_getipaddress(sock) 63 int sock; 64 { 65 struct iodesc *d; 66 register struct ether_arp *ap; 67 struct { 68 u_char header[HEADER_SIZE]; 69 struct ether_arp wrarp; 70 } wbuf; 71 struct { 72 u_char header[HEADER_SIZE]; 73 struct ether_arp rrarp; 74 } rbuf; 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(INADDR_ANY); 83 } 84 #ifdef RARP_DEBUG 85 if (debug) 86 printf("rarp: d=%x\n", (u_int)d); 87 #endif 88 89 ap = &wbuf.wrarp; 90 bzero(ap, sizeof(*ap)); 91 92 ap->arp_hrd = htons(ARPHRD_ETHER); 93 ap->arp_pro = htons(ETHERTYPE_IP); 94 ap->arp_hln = sizeof(ap->arp_sha); /* hardware address length */ 95 ap->arp_pln = sizeof(ap->arp_spa); /* protocol address length */ 96 ap->arp_op = htons(ARPOP_REQUEST); 97 bcopy(d->myea, ap->arp_sha, 6); 98 bcopy(d->myea, ap->arp_tha, 6); 99 100 if (sendrecv(d, 101 rarpsend, ap, sizeof(*ap), 102 rarprecv, &rbuf.rrarp, sizeof(rbuf.rrarp)) < 0) { 103 printf("No response for RARP request\n"); 104 return(INADDR_ANY); 105 } 106 107 return (myip); 108 } 109 110 /* 111 * Broadcast a RARP request (i.e. who knows who I am) 112 */ 113 static size_t 114 rarpsend(d, pkt, len) 115 register struct iodesc *d; 116 register void *pkt; 117 register size_t len; 118 { 119 120 #ifdef RARP_DEBUG 121 if (debug) 122 printf("rarpsend: called\n"); 123 #endif 124 125 return (sendether(d, pkt, len, bcea, ETHERTYPE_REVARP)); 126 } 127 128 /* 129 * Called when packet containing RARP is received 130 */ 131 static size_t 132 rarprecv(d, pkt, len, tleft) 133 register struct iodesc *d; 134 register void *pkt; 135 register size_t len; 136 time_t tleft; 137 { 138 register struct ether_header *eh; 139 register struct ether_arp *ap; 140 141 #ifdef RARP_DEBUG 142 if (debug) 143 printf("rarprecv: called\n"); 144 #endif 145 146 len = readether(d, pkt, len, tleft); 147 if (len == -1 || len < sizeof(struct ether_arp)) 148 goto bad; 149 150 eh = (struct ether_header *)pkt - 1; 151 if (ntohs(eh->ether_type) != ETHERTYPE_REVARP) 152 goto bad; 153 154 ap = (struct ether_arp *)pkt; 155 if (ntohs(ap->arp_op) != ARPOP_REPLY || 156 ntohs(ap->arp_pro) != ETHERTYPE_IP) 157 goto bad; 158 159 if (bcmp(ap->arp_tha, d->myea, 6)) 160 goto bad; 161 162 bcopy(ap->arp_tpa, (char *)&myip, sizeof(myip)); 163 bcopy(ap->arp_spa, (char *)&rootip, sizeof(rootip)); 164 165 return (0); 166 167 bad: 168 errno = 0; 169 return (-1); 170 } 171