1 /*-
2 * SPDX-License-Identifier: BSD-4-Clause
3 *
4 * Copyright (c) 1995 Bill Paul <[email protected]>.
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 <[email protected]>
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
ether_line(const char * l,struct ether_addr * e,char * hostname)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 *
ether_aton_r(const char * a,struct ether_addr * e)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 *
ether_aton(const char * a)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 *
ether_ntoa_r(const struct ether_addr * n,char * a)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 *
ether_ntoa(const struct ether_addr * n)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
ether_ntohost(char * hostname,const struct ether_addr * e)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
ether_hostton(const char * hostname,struct ether_addr * e)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