lib/libc/net/ether_addr.c

   1 /*
   2  * Copyright (c) 1995
   3  *      Bill Paul <wpaul@ctr.columbia.edu>.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by Bill Paul.
  16  * 4. Neither the name of the author nor the names of any co-contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY Bill Paul AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  *
  32  * ethernet address conversion and lookup routines
  33  *
  34  * Written by Bill Paul <wpaul@ctr.columbia.edu>
  35  * Center for Telecommunications Research
  36  * Columbia University, New York City
  37  *
  38  * $FreeBSD: src/lib/libc/net/ether_addr.c,v 1.10.2.5 2002/04/08 08:01:50 ru Exp $
  39  * $DragonFly: src/lib/libc/net/ether_addr.c,v 1.4 2005/11/13 02:04:47 swildner Exp $
  40  */
  41
  42 #include <stdio.h>
  43 #include <paths.h>
  44 #include <sys/types.h>
  45 #include <string.h>
  46 #include <stdlib.h>
  47 #include <sys/param.h>
  48 #include <sys/socket.h>
  49 #include <net/ethernet.h>
  50 #ifdef YP
  51 #include <rpc/rpc.h>
  52 #include <rpcsvc/yp_prot.h>
  53 #include <rpcsvc/ypclnt.h>
  54 #endif
  55
  56 #ifndef _PATH_ETHERS
  57 #define _PATH_ETHERS "/etc/ethers"
  58 #endif
  59
  60 /*
  61  * Parse a string of text containing an ethernet address and hostname
  62  * and separate it into its component parts.
  63  */
  64 int
  65 ether_line(const char *l, struct ether_addr *e, char *hostname)
  66 {
  67         int i, o[6];
  68
  69         i = sscanf(l, "%x:%x:%x:%x:%x:%x %s", &o[0], &o[1], &o[2],
  70                                               &o[3], &o[4], &o[5],
  71                                               hostname);
  72         if (i != 7)
  73                 return (i);
  74
  75         for (i=0; i<6; i++)
  76                 e->octet[i] = o[i];
  77         return (0);
  78 }
  79
  80 /*
  81  * Convert an ASCII representation of an ethernet address to
  82  * binary form.
  83  */
  84 struct ether_addr *
  85 ether_aton(const char *a)
  86 {
  87         int i;
  88         static struct ether_addr o;
  89         unsigned int o0, o1, o2, o3, o4, o5;
  90
  91         i = sscanf(a, "%x:%x:%x:%x:%x:%x", &o0, &o1, &o2, &o3, &o4, &o5);
  92
  93         if (i != 6)
  94                 return (NULL);
  95
  96         o.octet[0]=o0;
  97         o.octet[1]=o1;
  98         o.octet[2]=o2;
  99         o.octet[3]=o3;
 100         o.octet[4]=o4;
 101         o.octet[5]=o5;
 102
 103         return ((struct ether_addr *)&o);
 104 }
 105
 106 /*
 107  * Convert a binary representation of an ethernet address to
 108  * an ASCII string.
 109  */
 110 char *
 111 ether_ntoa(const struct ether_addr *n)
 112 {
 113         int i;
 114         static char a[18];
 115
 116         i = sprintf(a, "%02x:%02x:%02x:%02x:%02x:%02x",
 117             n->octet[0], n->octet[1], n->octet[2],
 118             n->octet[3], n->octet[4], n->octet[5]);
 119         if (i < 17)
 120                 return (NULL);
 121         return ((char *)&a);
 122 }
 123
 124 /*
 125  * Map an ethernet address to a hostname. Use either /etc/ethers or
 126  * NIS/YP.
 127  */
 128 int
 129 ether_ntohost(char *hostname, const struct ether_addr *e)
 130 {
 131         FILE *fp;
 132         char buf[BUFSIZ + 2];
 133         struct ether_addr local_ether;
 134         char local_host[MAXHOSTNAMELEN];
 135 #ifdef YP
 136         char *result;
 137         int resultlen;
 138         char *ether_a;
 139         char *yp_domain;
 140 #endif
 141         if ((fp = fopen(_PATH_ETHERS, "r")) == NULL)
 142                 return (1);
 143
 144         while (fgets(buf,BUFSIZ,fp)) {
 145                 if (buf[0] == '#')
 146                         continue;
 147 #ifdef YP
 148                 if (buf[0] == '+') {
 149                         if (yp_get_default_domain(&yp_domain))
 150                                 continue;
 151                         ether_a = ether_ntoa(e);
 152                         if (yp_match(yp_domain, "ethers.byaddr", ether_a,
 153                                 strlen(ether_a), &result, &resultlen)) {
 154                                 continue;
 155                         }
 156                         strncpy(buf, result, resultlen);
 157                         buf[resultlen] = '\0';
 158                         free(result);
 159                 }
 160 #endif
 161                 if (!ether_line(buf, &local_ether, local_host)) {
 162                         if (!bcmp((char *)&local_ether.octet[0],
 163                                 (char *)&e->octet[0], 6)) {
 164                         /* We have a match */
 165                                 strcpy(hostname, local_host);
 166                                 fclose(fp);
 167                                 return(0);
 168                         }
 169                 }
 170         }
 171         fclose(fp);
 172         return (1);
 173 }
 174
 175 /*
 176  * Map a hostname to an ethernet address using /etc/ethers or
 177  * NIS/YP.
 178  */
 179 int
 180 ether_hostton(const char *hostname, struct ether_addr *e)
 181 {
 182         FILE *fp;
 183         char buf[BUFSIZ + 2];
 184         struct ether_addr local_ether;
 185         char local_host[MAXHOSTNAMELEN];
 186 #ifdef YP
 187         char *result;
 188         int resultlen;
 189         char *yp_domain;
 190 #endif
 191         if ((fp = fopen(_PATH_ETHERS, "r")) == NULL)
 192                 return (1);
 193
 194         while (fgets(buf,BUFSIZ,fp)) {
 195                 if (buf[0] == '#')
 196                         continue;
 197 #ifdef YP
 198                 if (buf[0] == '+') {
 199                         if (yp_get_default_domain(&yp_domain))
 200                                 continue;
 201                         if (yp_match(yp_domain, "ethers.byname", hostname,
 202                                 strlen(hostname), &result, &resultlen)) {
 203                                 continue;
 204                         }
 205                         strncpy(buf, result, resultlen);
 206                         buf[resultlen] = '\0';
 207                         free(result);
 208                 }
 209 #endif
 210                 if (!ether_line(buf, &local_ether, local_host)) {
 211                         if (!strcmp(hostname, local_host)) {
 212                                 /* We have a match */
 213                                 bcopy((char *)&local_ether.octet[0],
 214                                         (char *)&e->octet[0], 6);
 215                                 fclose(fp);
 216                                 return(0);
 217                         }
 218                 }
 219         }
 220         fclose(fp);
 221         return (1);
 222 }