lib/libc/net/ether_addr.c

   1 /*
   2  * Copyright (c) 1995 Bill Paul <wpaul@ctr.columbia.edu>.
   3  * Copyright (c) 2007 Robert N. M. Watson
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  * 3. All advertising materials mentioning features or use of this software
  15  *    must display the following acknowledgement:
  16  *      This product includes software developed by Bill Paul.
  17  * 4. Neither the name of the author nor the names of any co-contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY Bill Paul AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  * ethernet address conversion and lookup routines
  34  *
  35  * Written by Bill Paul <wpaul@ctr.columbia.edu>
  36  * Center for Telecommunications Research
  37  * Columbia University, New York City
  38  *
  39  * $FreeBSD: src/lib/libc/net/ether_addr.c,v 1.17 2007/05/13 13:57:44 rwatson Exp $
  40  * $DragonFly: src/lib/libc/net/ether_addr.c,v 1.4 2005/11/13 02:04:47 swildner Exp $
  41  */
  42
  43 #include <sys/types.h>
  44 #include <sys/param.h>
  45 #include <sys/socket.h>
  46
  47 #include <net/ethernet.h>
  48
  49 #ifdef YP
  50 #include <rpc/rpc.h>
  51 #include <rpcsvc/yp_prot.h>
  52 #include <rpcsvc/ypclnt.h>
  53 #endif
  54
  55 #include <paths.h>
  56 #include <stdio.h>
  57 #include <stdlib.h>
  58 #include <string.h>
  59
  60 #ifndef _PATH_ETHERS
  61 #define _PATH_ETHERS    "/etc/ethers"
  62 #endif
  63
  64 /*
  65  * Parse a string of text containing an ethernet address and hostname and
  66  * separate it into its component parts.
  67  */
  68 int
  69 ether_line(const char *l, struct ether_addr *e, char *hostname)
  70 {
  71         int i, o[6];
  72
  73         i = sscanf(l, "%x:%x:%x:%x:%x:%x %s", &o[0], &o[1], &o[2], &o[3],
  74             &o[4], &o[5], hostname);
  75         if (i != 7)
  76                 return (i);
  77         for (i=0; i<6; i++)
  78                 e->octet[i] = o[i];
  79         return (0);
  80 }
  81
  82 /*
  83  * Convert an ASCII representation of an ethernet address to binary form.
  84  */
  85 struct ether_addr *
  86 ether_aton_r(const char *a, struct ether_addr *e)
  87 {
  88         int i;
  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         if (i != 6)
  93                 return (NULL);
  94         e->octet[0]=o0;
  95         e->octet[1]=o1;
  96         e->octet[2]=o2;
  97         e->octet[3]=o3;
  98         e->octet[4]=o4;
  99         e->octet[5]=o5;
 100         return (e);
 101 }
 102
 103 struct ether_addr *
 104 ether_aton(const char *a)
 105 {
 106         static struct ether_addr e;
 107
 108         return (ether_aton_r(a, &e));
 109 }
 110
 111 /*
 112  * Convert a binary representation of an ethernet address to an ASCII string.
 113  */
 114 char *
 115 ether_ntoa_r(const struct ether_addr *n, char *a)
 116 {
 117         int i;
 118
 119         i = sprintf(a, "%02x:%02x:%02x:%02x:%02x:%02x", n->octet[0],
 120             n->octet[1], n->octet[2], n->octet[3], n->octet[4], n->octet[5]);
 121         if (i < 17)
 122                 return (NULL);
 123         return (a);
 124 }
 125
 126 char *
 127 ether_ntoa(const struct ether_addr *n)
 128 {
 129         static char a[18];
 130
 131         return (ether_ntoa_r(n, a));
 132 }
 133
 134 /*
 135  * Map an ethernet address to a hostname. Use either /etc/ethers or NIS/YP.
 136  */
 137 int
 138 ether_ntohost(char *hostname, const struct ether_addr *e)
 139 {
 140         FILE *fp;
 141         char buf[BUFSIZ + 2];
 142         struct ether_addr local_ether;
 143         char local_host[MAXHOSTNAMELEN];
 144 #ifdef YP
 145         char *result;
 146         int resultlen;
 147         char *ether_a;
 148         char *yp_domain;
 149 #endif
 150
 151         if ((fp = fopen(_PATH_ETHERS, "r")) == NULL)
 152                 return (1);
 153         while (fgets(buf,BUFSIZ,fp)) {
 154                 if (buf[0] == '#')
 155                         continue;
 156 #ifdef YP
 157                 if (buf[0] == '+') {
 158                         if (yp_get_default_domain(&yp_domain))
 159                                 continue;
 160                         ether_a = ether_ntoa(e);
 161                         if (yp_match(yp_domain, "ethers.byaddr", ether_a,
 162                             strlen(ether_a), &result, &resultlen)) {
 163                                 continue;
 164                         }
 165                         strncpy(buf, result, resultlen);
 166                         buf[resultlen] = '\0';
 167                         free(result);
 168                 }
 169 #endif
 170                 if (!ether_line(buf, &local_ether, local_host)) {
 171                         if (!bcmp((char *)&local_ether.octet[0],
 172                             (char *)&e->octet[0], 6)) {
 173                                 /* We have a match. */
 174                                 strcpy(hostname, local_host);
 175                                 fclose(fp);
 176                                 return(0);
 177                         }
 178                 }
 179         }
 180         fclose(fp);
 181         return (1);
 182 }
 183
 184 /*
 185  * Map a hostname to an ethernet address using /etc/ethers or NIS/YP.
 186  */
 187 int
 188 ether_hostton(const char *hostname, struct ether_addr *e)
 189 {
 190         FILE *fp;
 191         char buf[BUFSIZ + 2];
 192         struct ether_addr local_ether;
 193         char local_host[MAXHOSTNAMELEN];
 194 #ifdef YP
 195         char *result;
 196         int resultlen;
 197         char *yp_domain;
 198 #endif
 199
 200         if ((fp = fopen(_PATH_ETHERS, "r")) == NULL)
 201                 return (1);
 202         while (fgets(buf,BUFSIZ,fp)) {
 203                 if (buf[0] == '#')
 204                         continue;
 205 #ifdef YP
 206                 if (buf[0] == '+') {
 207                         if (yp_get_default_domain(&yp_domain))
 208                                 continue;
 209                         if (yp_match(yp_domain, "ethers.byname", hostname,
 210                             strlen(hostname), &result, &resultlen)) {
 211                                 continue;
 212                         }
 213                         strncpy(buf, result, resultlen);
 214                         buf[resultlen] = '\0';
 215                         free(result);
 216                 }
 217 #endif
 218                 if (!ether_line(buf, &local_ether, local_host)) {
 219                         if (!strcmp(hostname, local_host)) {
 220                                 /* We have a match. */
 221                                 bcopy((char *)&local_ether.octet[0],
 222                                     (char *)&e->octet[0], 6);
 223                                 fclose(fp);
 224                                 return(0);
 225                         }
 226                 }
 227         }
 228         fclose(fp);
 229         return (1);
 230 }