sys/lib/libsa/rarp.c

   1 /*      $NetBSD: rarp.c,v 1.31 2011/05/11 16:23:40 zoltan 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 <net/if_ether.h>
  45 #include <netinet/in.h>
  46
  47 #include <netinet/in_systm.h>
  48
  49 #ifdef _STANDALONE
  50 #include <lib/libkern/libkern.h>
  51 #else
  52 #include <string.h>
  53 #endif
  54
  55 #include "stand.h"
  56 #include "net.h"
  57
  58
  59 /*
  60  * Ethernet Address Resolution Protocol.
  61  *
  62  * See RFC 826 for protocol description.  Structure below is adapted
  63  * to resolving internet addresses.  Field names used correspond to
  64  * RFC 826.
  65  */
  66 struct ether_arp {
  67         struct   arphdr ea_hdr;                 /* fixed-size header */
  68         u_int8_t arp_sha[ETHER_ADDR_LEN];       /* sender hardware address */
  69         u_int8_t arp_spa[4];                    /* sender protocol address */
  70         u_int8_t arp_tha[ETHER_ADDR_LEN];       /* target hardware address */
  71         u_int8_t arp_tpa[4];                    /* target protocol address */
  72 };
  73 #define arp_hrd ea_hdr.ar_hrd
  74 #define arp_pro ea_hdr.ar_pro
  75 #define arp_hln ea_hdr.ar_hln
  76 #define arp_pln ea_hdr.ar_pln
  77 #define arp_op  ea_hdr.ar_op
  78
  79 static ssize_t rarpsend(struct iodesc *, void *, size_t);
  80 static ssize_t rarprecv(struct iodesc *, void *, size_t, saseconds_t);
  81
  82 /*
  83  * Ethernet (Reverse) Address Resolution Protocol (see RFC 903, and 826).
  84  */
  85 int
  86 rarp_getipaddress(int sock)
  87 {
  88         struct iodesc *d;
  89         struct ether_arp *ap;
  90         struct {
  91                 u_char header[ETHERNET_HEADER_SIZE];
  92                 struct {
  93                         struct ether_arp arp;
  94                         u_char pad[18];         /* 60 - sizeof(arp) */
  95                 } data;
  96         } wbuf;
  97         struct {
  98                 u_char header[ETHERNET_HEADER_SIZE];
  99                 struct {
 100                         struct ether_arp arp;
 101                         u_char pad[24];         /* extra space */
 102                 } data;
 103         } rbuf;
 104
 105 #ifdef RARP_DEBUG
 106         if (debug)
 107                 printf("rarp: socket=%d\n", sock);
 108 #endif
 109         if (!(d = socktodesc(sock))) {
 110                 printf("rarp: bad socket. %d\n", sock);
 111                 return -1;
 112         }
 113 #ifdef RARP_DEBUG
 114         if (debug)
 115                 printf("rarp: d=%lx\n", (u_long)d);
 116 #endif
 117
 118         (void)memset(&wbuf.data, 0, sizeof(wbuf.data));
 119         ap = &wbuf.data.arp;
 120         ap->arp_hrd = htons(ARPHRD_ETHER);
 121         ap->arp_pro = htons(ETHERTYPE_IP);
 122         ap->arp_hln = sizeof(ap->arp_sha); /* hardware address length */
 123         ap->arp_pln = sizeof(ap->arp_spa); /* protocol address length */
 124         ap->arp_op = htons(ARPOP_REVREQUEST);
 125         (void)memcpy(ap->arp_sha, d->myea, 6);
 126         (void)memcpy(ap->arp_tha, d->myea, 6);
 127
 128         if (sendrecv(d,
 129             rarpsend, &wbuf.data, sizeof(wbuf.data),
 130             rarprecv, &rbuf.data, sizeof(rbuf.data)) < 0)
 131         {
 132                 printf("No response for RARP request\n");
 133                 return -1;
 134         }
 135
 136         ap = &rbuf.data.arp;
 137         (void)memcpy(&myip, ap->arp_tpa, sizeof(myip));
 138 #if 0
 139         /* XXX - Can NOT assume this is our root server! */
 140         (void)memcpy(&rootip, ap->arp_spa, sizeof(rootip));
 141 #endif
 142
 143         /* Compute our "natural" netmask. */
 144         if (IN_CLASSA(myip.s_addr))
 145                 netmask = IN_CLASSA_NET;
 146         else if (IN_CLASSB(myip.s_addr))
 147                 netmask = IN_CLASSB_NET;
 148         else
 149                 netmask = IN_CLASSC_NET;
 150
 151         d->myip = myip;
 152         return 0;
 153 }
 154
 155 /*
 156  * Broadcast a RARP request (i.e. who knows who I am)
 157  */
 158 static ssize_t
 159 rarpsend(struct iodesc *d, void *pkt, size_t len)
 160 {
 161
 162 #ifdef RARP_DEBUG
 163         if (debug)
 164                 printf("rarpsend: called\n");
 165 #endif
 166
 167         return sendether(d, pkt, len, bcea, ETHERTYPE_REVARP);
 168 }
 169
 170 /*
 171  * Returns 0 if this is the packet we're waiting for
 172  * else -1 (and errno == 0)
 173  */
 174 static ssize_t
 175 rarprecv(struct iodesc *d, void *pkt, size_t len, saseconds_t tleft)
 176 {
 177         ssize_t n;
 178         struct ether_arp *ap;
 179         u_int16_t etype;        /* host order */
 180
 181 #ifdef RARP_DEBUG
 182         if (debug)
 183                 printf("rarprecv: ");
 184 #endif
 185
 186         n = readether(d, pkt, len, tleft, &etype);
 187         errno = 0;      /* XXX */
 188         if (n == -1 || (size_t)n < sizeof(struct ether_arp)) {
 189 #ifdef RARP_DEBUG
 190                 if (debug)
 191                         printf("bad len=%d\n", (int)n);
 192 #endif
 193                 return -1;
 194         }
 195
 196         if (etype != ETHERTYPE_REVARP) {
 197 #ifdef RARP_DEBUG
 198                 if (debug)
 199                         printf("bad type=0x%x\n", etype);
 200 #endif
 201                 return -1;
 202         }
 203
 204         ap = (struct ether_arp *)pkt;
 205         if (ap->arp_hrd != htons(ARPHRD_ETHER) ||
 206             ap->arp_pro != htons(ETHERTYPE_IP) ||
 207             ap->arp_hln != sizeof(ap->arp_sha) ||
 208             ap->arp_pln != sizeof(ap->arp_spa) )
 209         {
 210 #ifdef RARP_DEBUG
 211                 if (debug)
 212                         printf("bad hrd/pro/hln/pln\n");
 213 #endif
 214                 return -1;
 215         }
 216
 217         if (ap->arp_op != htons(ARPOP_REVREPLY)) {
 218 #ifdef RARP_DEBUG
 219                 if (debug)
 220                         printf("bad op=0x%x\n", ntohs(ap->arp_op));
 221 #endif
 222                 return -1;
 223         }
 224
 225         /* Is the reply for our Ethernet address? */
 226         if (memcmp(ap->arp_tha, d->myea, 6)) {
 227 #ifdef RARP_DEBUG
 228                 if (debug)
 229                         printf("unwanted address\n");
 230 #endif
 231                 return -1;
 232         }
 233
 234         /* We have our answer. */
 235 #ifdef RARP_DEBUG
 236         if (debug)
 237                 printf("got it\n");
 238 #endif
 239         return n;
 240 }