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 * XXX Hack, constrain hostname scan to 255 characters. Hardwired from
69 * MAXHOSTNAMELEN which is 256. The API is badly broken but cannot be
70 * changed.
71 */
72 int
ether_line(const char * l,struct ether_addr * e,char * hostname)73 ether_line(const char *l, struct ether_addr *e, char *hostname)
74 {
75 int i, o[6];
76
77 i = sscanf(l, "%x:%x:%x:%x:%x:%x %255s", &o[0], &o[1], &o[2], &o[3],
78 &o[4], &o[5], hostname);
79 if (i != 7)
80 return (i);
81 for (i=0; i<6; i++)
82 e->octet[i] = o[i];
83 return (0);
84 }
85
86 /*
87 * Convert an ASCII representation of an ethernet address to binary form.
88 */
89 struct ether_addr *
ether_aton_r(const char * a,struct ether_addr * e)90 ether_aton_r(const char *a, struct ether_addr *e)
91 {
92 int i;
93 unsigned int o0, o1, o2, o3, o4, o5;
94
95 i = sscanf(a, "%x:%x:%x:%x:%x:%x", &o0, &o1, &o2, &o3, &o4, &o5);
96 if (i != 6)
97 return (NULL);
98 e->octet[0]=o0;
99 e->octet[1]=o1;
100 e->octet[2]=o2;
101 e->octet[3]=o3;
102 e->octet[4]=o4;
103 e->octet[5]=o5;
104 return (e);
105 }
106
107 struct ether_addr *
ether_aton(const char * a)108 ether_aton(const char *a)
109 {
110 static struct ether_addr e;
111
112 return (ether_aton_r(a, &e));
113 }
114
115 /*
116 * Convert a binary representation of an ethernet address to an ASCII string.
117 */
118 char *
ether_ntoa_r(const struct ether_addr * n,char * a)119 ether_ntoa_r(const struct ether_addr *n, char *a)
120 {
121 int i;
122
123 i = sprintf(a, "%02x:%02x:%02x:%02x:%02x:%02x", n->octet[0],
124 n->octet[1], n->octet[2], n->octet[3], n->octet[4], n->octet[5]);
125 if (i < 17)
126 return (NULL);
127 return (a);
128 }
129
130 char *
ether_ntoa(const struct ether_addr * n)131 ether_ntoa(const struct ether_addr *n)
132 {
133 static char a[18];
134
135 return (ether_ntoa_r(n, a));
136 }
137
138 /*
139 * Map an ethernet address to a hostname. Use either /etc/ethers or NIS/YP.
140 */
141 int
ether_ntohost(char * hostname,const struct ether_addr * e)142 ether_ntohost(char *hostname, const struct ether_addr *e)
143 {
144 FILE *fp;
145 char buf[BUFSIZ + 2];
146 struct ether_addr local_ether;
147 char local_host[MAXHOSTNAMELEN];
148 #ifdef YP
149 char *result;
150 int resultlen;
151 char *ether_a;
152 char *yp_domain;
153 #endif
154
155 if ((fp = fopen(_PATH_ETHERS, "r")) == NULL)
156 return (1);
157 while (fgets(buf,BUFSIZ,fp)) {
158 if (buf[0] == '#')
159 continue;
160 #ifdef YP
161 if (buf[0] == '+') {
162 if (yp_get_default_domain(&yp_domain))
163 continue;
164 ether_a = ether_ntoa(e);
165 if (yp_match(yp_domain, "ethers.byaddr", ether_a,
166 strlen(ether_a), &result, &resultlen)) {
167 continue;
168 }
169 strncpy(buf, result, resultlen);
170 buf[resultlen] = '\0';
171 free(result);
172 }
173 #endif
174 if (!ether_line(buf, &local_ether, local_host)) {
175 if (!bcmp((char *)&local_ether.octet[0],
176 (char *)&e->octet[0], 6)) {
177 /* We have a match. */
178 strcpy(hostname, local_host);
179 fclose(fp);
180 return(0);
181 }
182 }
183 }
184 fclose(fp);
185 return (1);
186 }
187
188 /*
189 * Map a hostname to an ethernet address using /etc/ethers or NIS/YP.
190 */
191 int
ether_hostton(const char * hostname,struct ether_addr * e)192 ether_hostton(const char *hostname, struct ether_addr *e)
193 {
194 FILE *fp;
195 char buf[BUFSIZ + 2];
196 struct ether_addr local_ether;
197 char local_host[MAXHOSTNAMELEN];
198 #ifdef YP
199 char *result;
200 int resultlen;
201 char *yp_domain;
202 #endif
203
204 if ((fp = fopen(_PATH_ETHERS, "r")) == NULL)
205 return (1);
206 while (fgets(buf,BUFSIZ,fp)) {
207 if (buf[0] == '#')
208 continue;
209 #ifdef YP
210 if (buf[0] == '+') {
211 if (yp_get_default_domain(&yp_domain))
212 continue;
213 if (yp_match(yp_domain, "ethers.byname", hostname,
214 strlen(hostname), &result, &resultlen)) {
215 continue;
216 }
217 strncpy(buf, result, resultlen);
218 buf[resultlen] = '\0';
219 free(result);
220 }
221 #endif
222 if (!ether_line(buf, &local_ether, local_host)) {
223 if (!strcmp(hostname, local_host)) {
224 /* We have a match. */
225 bcopy((char *)&local_ether.octet[0],
226 (char *)&e->octet[0], 6);
227 fclose(fp);
228 return(0);
229 }
230 }
231 }
232 fclose(fp);
233 return (1);
234 }
235