1 /*- 2 * SPDX-License-Identifier: BSD-4-Clause 3 * 4 * Copyright (c) 1995 Bill Paul <wpaul@ctr.columbia.edu>. 5 * Copyright (c) 2007 Robert N. M. Watson 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by Bill Paul. 19 * 4. Neither the name of the author nor the names of any co-contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY Bill Paul AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 * 35 * ethernet address conversion and lookup routines 36 * 37 * Written by Bill Paul <wpaul@ctr.columbia.edu> 38 * Center for Telecommunications Research 39 * Columbia University, New York City 40 */ 41 42 #include <sys/cdefs.h> 43 __FBSDID("$FreeBSD$"); 44 45 #include <sys/param.h> 46 #include <sys/socket.h> 47 48 #include <net/ethernet.h> 49 50 #ifdef YP 51 #include <rpc/rpc.h> 52 #include <rpcsvc/yp_prot.h> 53 #include <rpcsvc/ypclnt.h> 54 #endif 55 56 #include <paths.h> 57 #include <stdio.h> 58 #include <stdlib.h> 59 #include <string.h> 60 61 #ifndef _PATH_ETHERS 62 #define _PATH_ETHERS "/etc/ethers" 63 #endif 64 65 /* 66 * Parse a string of text containing an ethernet address and hostname and 67 * separate it into its component parts. 68 */ 69 int 70 ether_line(const char *l, struct ether_addr *e, char *hostname) 71 { 72 int i, o[6]; 73 74 i = sscanf(l, "%x:%x:%x:%x:%x:%x %s", &o[0], &o[1], &o[2], &o[3], 75 &o[4], &o[5], hostname); 76 if (i == 7) { 77 for (i = 0; i < 6; i++) 78 e->octet[i] = o[i]; 79 return (0); 80 } else { 81 return (-1); 82 } 83 } 84 85 /* 86 * Convert an ASCII representation of an ethernet address to binary form. 87 */ 88 struct ether_addr * 89 ether_aton_r(const char *a, struct ether_addr *e) 90 { 91 int i; 92 unsigned int o0, o1, o2, o3, o4, o5; 93 94 i = sscanf(a, "%x:%x:%x:%x:%x:%x", &o0, &o1, &o2, &o3, &o4, &o5); 95 if (i != 6) 96 return (NULL); 97 e->octet[0]=o0; 98 e->octet[1]=o1; 99 e->octet[2]=o2; 100 e->octet[3]=o3; 101 e->octet[4]=o4; 102 e->octet[5]=o5; 103 return (e); 104 } 105 106 struct ether_addr * 107 ether_aton(const char *a) 108 { 109 static struct ether_addr e; 110 111 return (ether_aton_r(a, &e)); 112 } 113 114 /* 115 * Convert a binary representation of an ethernet address to an ASCII string. 116 */ 117 char * 118 ether_ntoa_r(const struct ether_addr *n, char *a) 119 { 120 int i; 121 122 i = sprintf(a, "%02x:%02x:%02x:%02x:%02x:%02x", n->octet[0], 123 n->octet[1], n->octet[2], n->octet[3], n->octet[4], n->octet[5]); 124 if (i < 17) 125 return (NULL); 126 return (a); 127 } 128 129 char * 130 ether_ntoa(const struct ether_addr *n) 131 { 132 static char a[18]; 133 134 return (ether_ntoa_r(n, a)); 135 } 136 137 /* 138 * Map an ethernet address to a hostname. Use either /etc/ethers or NIS/YP. 139 */ 140 int 141 ether_ntohost(char *hostname, const struct ether_addr *e) 142 { 143 FILE *fp; 144 char buf[BUFSIZ + 2]; 145 struct ether_addr local_ether; 146 char local_host[MAXHOSTNAMELEN]; 147 #ifdef YP 148 char *result; 149 int resultlen; 150 char *ether_a; 151 char *yp_domain; 152 #endif 153 154 if ((fp = fopen(_PATH_ETHERS, "re")) == NULL) 155 return (1); 156 while (fgets(buf,BUFSIZ,fp)) { 157 if (buf[0] == '#') 158 continue; 159 #ifdef YP 160 if (buf[0] == '+') { 161 if (yp_get_default_domain(&yp_domain)) 162 continue; 163 ether_a = ether_ntoa(e); 164 if (yp_match(yp_domain, "ethers.byaddr", ether_a, 165 strlen(ether_a), &result, &resultlen)) { 166 continue; 167 } 168 strncpy(buf, result, resultlen); 169 buf[resultlen] = '\0'; 170 free(result); 171 } 172 #endif 173 if (!ether_line(buf, &local_ether, local_host)) { 174 if (!bcmp((char *)&local_ether.octet[0], 175 (char *)&e->octet[0], 6)) { 176 /* We have a match. */ 177 strcpy(hostname, local_host); 178 fclose(fp); 179 return(0); 180 } 181 } 182 } 183 fclose(fp); 184 return (1); 185 } 186 187 /* 188 * Map a hostname to an ethernet address using /etc/ethers or NIS/YP. 189 */ 190 int 191 ether_hostton(const char *hostname, struct ether_addr *e) 192 { 193 FILE *fp; 194 char buf[BUFSIZ + 2]; 195 struct ether_addr local_ether; 196 char local_host[MAXHOSTNAMELEN]; 197 #ifdef YP 198 char *result; 199 int resultlen; 200 char *yp_domain; 201 #endif 202 203 if ((fp = fopen(_PATH_ETHERS, "re")) == NULL) 204 return (1); 205 while (fgets(buf,BUFSIZ,fp)) { 206 if (buf[0] == '#') 207 continue; 208 #ifdef YP 209 if (buf[0] == '+') { 210 if (yp_get_default_domain(&yp_domain)) 211 continue; 212 if (yp_match(yp_domain, "ethers.byname", hostname, 213 strlen(hostname), &result, &resultlen)) { 214 continue; 215 } 216 strncpy(buf, result, resultlen); 217 buf[resultlen] = '\0'; 218 free(result); 219 } 220 #endif 221 if (!ether_line(buf, &local_ether, local_host)) { 222 if (!strcmp(hostname, local_host)) { 223 /* We have a match. */ 224 bcopy((char *)&local_ether.octet[0], 225 (char *)&e->octet[0], 6); 226 fclose(fp); 227 return(0); 228 } 229 } 230 } 231 fclose(fp); 232 return (1); 233 } 234