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. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  * @(#) Header: arp.c,v 1.5 93/07/15 05:52:26 leres Exp  (LBL)
  37  */
  38 #include <sys/param.h>
  39 #include <sys/socket.h>
  40 #include <net/if.h>
  41 #include <netinet/in.h>
  42 #include <netinet/if_ether.h>
  43
  44 #include <netinet/in_systm.h>
  45
  46 #include <string.h>
  47
  48 #include "stand.h"
  49 #include "net.h"
  50 #include "netif.h"
  51
  52
  53 static ssize_t rarpsend(struct iodesc *, void *, size_t);
  54 static ssize_t rarprecv(struct iodesc *, void *, size_t, time_t);
  55
  56 /*
  57  * Ethernet (Reverse) Address Resolution Protocol (see RFC 903, and 826).
  58  */
  59 int
  60 rarp_getipaddress(int sock)
  61 {
  62         struct iodesc *d;
  63         struct ether_arp *ap;
  64         struct {
  65                 u_char header[ETHER_SIZE];
  66                 struct {
  67                         struct ether_arp arp;
  68                         u_char pad[18];         /* 60 - sizeof(arp) */
  69                 } data;
  70         } wbuf;
  71         struct {
  72                 u_char header[ETHER_SIZE];
  73                 struct {
  74                         struct ether_arp arp;
  75                         u_char pad[24];         /* extra space */
  76                 } data;
  77         } rbuf;
  78
  79 #ifdef RARP_DEBUG
  80         if (debug)
  81                 printf("rarp: socket=%d\n", sock);
  82 #endif
  83         if (!(d = socktodesc(sock))) {
  84                 printf("rarp: bad socket. %d\n", sock);
  85                 return (-1);
  86         }
  87 #ifdef RARP_DEBUG
  88         if (debug)
  89                 printf("rarp: d=%x\n", (u_int)d);
  90 #endif
  91
  92         bzero((char*)&wbuf.data, sizeof(wbuf.data));
  93         ap = &wbuf.data.arp;
  94         ap->arp_hrd = htons(ARPHRD_ETHER);
  95         ap->arp_pro = htons(ETHERTYPE_IP);
  96         ap->arp_hln = sizeof(ap->arp_sha); /* hardware address length */
  97         ap->arp_pln = sizeof(ap->arp_spa); /* protocol address length */
  98         ap->arp_op = htons(ARPOP_REVREQUEST);
  99         bcopy(d->myea, ap->arp_sha, 6);
 100         bcopy(d->myea, ap->arp_tha, 6);
 101
 102         if (sendrecv(d,
 103             rarpsend, &wbuf.data, sizeof(wbuf.data),
 104             rarprecv, &rbuf.data, sizeof(rbuf.data)) < 0)
 105         {
 106                 printf("No response for RARP request\n");
 107                 return (-1);
 108         }
 109
 110         ap = &rbuf.data.arp;
 111         bcopy(ap->arp_tpa, (char *)&myip, sizeof(myip));
 112 #if 0
 113         /* XXX - Can NOT assume this is our root server! */
 114         bcopy(ap->arp_spa, (char *)&rootip, sizeof(rootip));
 115 #endif
 116
 117         /* Compute our "natural" netmask. */
 118         if (IN_CLASSA(myip.s_addr))
 119                 netmask = IN_CLASSA_NET;
 120         else if (IN_CLASSB(myip.s_addr))
 121                 netmask = IN_CLASSB_NET;
 122         else
 123                 netmask = IN_CLASSC_NET;
 124
 125         d->myip = myip;
 126         return (0);
 127 }
 128
 129 /*
 130  * Broadcast a RARP request (i.e. who knows who I am)
 131  */
 132 static ssize_t
 133 rarpsend(struct iodesc *d, void *pkt, size_t len)
 134 {
 135
 136 #ifdef RARP_DEBUG
 137         if (debug)
 138                 printf("rarpsend: called\n");
 139 #endif
 140
 141         return (sendether(d, pkt, len, bcea, ETHERTYPE_REVARP));
 142 }
 143
 144 /*
 145  * Returns 0 if this is the packet we're waiting for
 146  * else -1 (and errno == 0)
 147  */
 148 static ssize_t
 149 rarprecv(struct iodesc *d, void *pkt, size_t len, time_t tleft)
 150 {
 151         ssize_t n;
 152         struct ether_arp *ap;
 153         u_int16_t etype;        /* host order */
 154
 155 #ifdef RARP_DEBUG
 156         if (debug)
 157                 printf("rarprecv: ");
 158 #endif
 159
 160         n = readether(d, pkt, len, tleft, &etype);
 161         errno = 0;      /* XXX */
 162         if (n == -1 || n < sizeof(struct ether_arp)) {
 163 #ifdef RARP_DEBUG
 164                 if (debug)
 165                         printf("bad len=%d\n", n);
 166 #endif
 167                 return (-1);
 168         }
 169
 170         if (etype != ETHERTYPE_REVARP) {
 171 #ifdef RARP_DEBUG
 172                 if (debug)
 173                         printf("bad type=0x%x\n", etype);
 174 #endif
 175                 return (-1);
 176         }
 177
 178         ap = (struct ether_arp *)pkt;
 179         if (ap->arp_hrd != htons(ARPHRD_ETHER) ||
 180             ap->arp_pro != htons(ETHERTYPE_IP) ||
 181             ap->arp_hln != sizeof(ap->arp_sha) ||
 182             ap->arp_pln != sizeof(ap->arp_spa) )
 183         {
 184 #ifdef RARP_DEBUG
 185                 if (debug)
 186                         printf("bad hrd/pro/hln/pln\n");
 187 #endif
 188                 return (-1);
 189         }
 190
 191         if (ap->arp_op != htons(ARPOP_REVREPLY)) {
 192 #ifdef RARP_DEBUG
 193                 if (debug)
 194                         printf("bad op=0x%x\n", ntohs(ap->arp_op));
 195 #endif
 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                 return (-1);
 206         }
 207
 208         /* We have our answer. */
 209 #ifdef RARP_DEBUG
 210         if (debug)
 211                 printf("got it\n");
 212 #endif
 213         return (n);
 214 }