lib/libstand/rarp.c

   1 /*      $NetBSD: rarp.c,v 1.16 1997/07/07 15:52:52 drochner Exp $       */
   2 /* $DragonFly: src/lib/libstand/rarp.c,v 1.3 2005/12/11 02:27:26 swildner Exp $                                                 */
   3
   4 /*
   5  * Copyright (c) 1992 Regents of the University of California.
   6  * All rights reserved.
   7  *
   8  * This software was developed by the Computer Systems Engineering group
   9  * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
  10  * contributed to Berkeley.
  11  *
  12  * Redistribution and use in source and binary forms, with or without
  13  * modification, are permitted provided that the following conditions
  14  * are met:
  15  * 1. Redistributions of source code must retain the above copyright
  16  *    notice, this list of conditions and the following disclaimer.
  17  * 2. Redistributions in binary form must reproduce the above copyright
  18  *    notice, this list of conditions and the following disclaimer in the
  19  *    documentation and/or other materials provided with the distribution.
  20  * 3. All advertising materials mentioning features or use of this software
  21  *    must display the following acknowledgement:
  22  *      This product includes software developed by the University of
  23  *      California, Lawrence Berkeley Laboratory and its contributors.
  24  * 4. Neither the name of the University nor the names of its contributors
  25  *    may be used to endorse or promote products derived from this software
  26  *    without specific prior written permission.
  27  *
  28  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  38  * SUCH DAMAGE.
  39  *
  40  * @(#) Header: arp.c,v 1.5 93/07/15 05:52:26 leres Exp  (LBL)
  41  */
  42 #include <sys/param.h>
  43 #include <sys/socket.h>
  44 #include <net/if.h>
  45 #include <netinet/in.h>
  46 #include <netinet/if_ether.h>
  47
  48 #include <netinet/in_systm.h>
  49
  50 #include <string.h>
  51
  52 #include "stand.h"
  53 #include "net.h"
  54 #include "netif.h"
  55
  56
  57 static ssize_t rarpsend(struct iodesc *, void *, size_t);
  58 static ssize_t rarprecv(struct iodesc *, void *, size_t, time_t);
  59
  60 /*
  61  * Ethernet (Reverse) Address Resolution Protocol (see RFC 903, and 826).
  62  */
  63 int
  64 rarp_getipaddress(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  */
 136 static ssize_t
 137 rarpsend(struct iodesc *d, void *pkt, size_t len)
 138 {
 139
 140 #ifdef RARP_DEBUG
 141         if (debug)
 142                 printf("rarpsend: called\n");
 143 #endif
 144
 145         return (sendether(d, pkt, len, bcea, ETHERTYPE_REVARP));
 146 }
 147
 148 /*
 149  * Returns 0 if this is the packet we're waiting for
 150  * else -1 (and errno == 0)
 151  */
 152 static ssize_t
 153 rarprecv(struct iodesc *d, void *pkt, size_t len, time_t tleft)
 154 {
 155         ssize_t n;
 156         struct ether_arp *ap;
 157         u_int16_t etype;        /* host order */
 158
 159 #ifdef RARP_DEBUG
 160         if (debug)
 161                 printf("rarprecv: ");
 162 #endif
 163
 164         n = readether(d, pkt, len, tleft, &etype);
 165         errno = 0;      /* XXX */
 166         if (n == -1 || n < sizeof(struct ether_arp)) {
 167 #ifdef RARP_DEBUG
 168                 if (debug)
 169                         printf("bad len=%d\n", n);
 170 #endif
 171                 return (-1);
 172         }
 173
 174         if (etype != ETHERTYPE_REVARP) {
 175 #ifdef RARP_DEBUG
 176                 if (debug)
 177                         printf("bad type=0x%x\n", etype);
 178 #endif
 179                 return (-1);
 180         }
 181
 182         ap = (struct ether_arp *)pkt;
 183         if (ap->arp_hrd != htons(ARPHRD_ETHER) ||
 184             ap->arp_pro != htons(ETHERTYPE_IP) ||
 185             ap->arp_hln != sizeof(ap->arp_sha) ||
 186             ap->arp_pln != sizeof(ap->arp_spa) )
 187         {
 188 #ifdef RARP_DEBUG
 189                 if (debug)
 190                         printf("bad hrd/pro/hln/pln\n");
 191 #endif
 192                 return (-1);
 193         }
 194
 195         if (ap->arp_op != htons(ARPOP_REVREPLY)) {
 196 #ifdef RARP_DEBUG
 197                 if (debug)
 198                         printf("bad op=0x%x\n", ntohs(ap->arp_op));
 199 #endif
 200                 return (-1);
 201         }
 202
 203         /* Is the reply for our Ethernet address? */
 204         if (bcmp(ap->arp_tha, d->myea, 6)) {
 205 #ifdef RARP_DEBUG
 206                 if (debug)
 207                         printf("unwanted address\n");
 208 #endif
 209                 return (-1);
 210         }
 211
 212         /* We have our answer. */
 213 #ifdef RARP_DEBUG
 214         if (debug)
 215                 printf("got it\n");
 216 #endif
 217         return (n);
 218 }