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
40#include <sys/cdefs.h>
41__FBSDID("$FreeBSD$");
42
43#include <sys/param.h>
44#include <sys/socket.h>
45
46#include <net/ethernet.h>
47
48#ifdef YP
49#include <rpc/rpc.h>
50#include <rpcsvc/yp_prot.h>
51#include <rpcsvc/ypclnt.h>
52#endif
53
54#include <paths.h>
55#include <stdio.h>
56#include <stdlib.h>
57#include <string.h>
58
59#ifndef _PATH_ETHERS
60#define	_PATH_ETHERS	"/etc/ethers"
61#endif
62
63/*
64 * Parse a string of text containing an ethernet address and hostname and
65 * separate it into its component parts.
66 */
67int
68ether_line(const char *l, struct ether_addr *e, char *hostname)
69{
70	int i, o[6];
71
72	i = sscanf(l, "%x:%x:%x:%x:%x:%x %s", &o[0], &o[1], &o[2], &o[3],
73	    &o[4], &o[5], hostname);
74	if (i == 7) {
75		for (i = 0; i < 6; i++)
76			e->octet[i] = o[i];
77		return (0);
78	} else {
79		return (-1);
80	}
81}
82
83/*
84 * Convert an ASCII representation of an ethernet address to binary form.
85 */
86struct ether_addr *
87ether_aton_r(const char *a, struct ether_addr *e)
88{
89	int i;
90	unsigned int o0, o1, o2, o3, o4, o5;
91
92	i = sscanf(a, "%x:%x:%x:%x:%x:%x", &o0, &o1, &o2, &o3, &o4, &o5);
93	if (i != 6)
94		return (NULL);
95	e->octet[0]=o0;
96	e->octet[1]=o1;
97	e->octet[2]=o2;
98	e->octet[3]=o3;
99	e->octet[4]=o4;
100	e->octet[5]=o5;
101	return (e);
102}
103
104struct ether_addr *
105ether_aton(const char *a)
106{
107	static struct ether_addr e;
108
109	return (ether_aton_r(a, &e));
110}
111
112/*
113 * Convert a binary representation of an ethernet address to an ASCII string.
114 */
115char *
116ether_ntoa_r(const struct ether_addr *n, char *a)
117{
118	int i;
119
120	i = sprintf(a, "%02x:%02x:%02x:%02x:%02x:%02x", n->octet[0],
121	    n->octet[1], n->octet[2], n->octet[3], n->octet[4], n->octet[5]);
122	if (i < 17)
123		return (NULL);
124	return (a);
125}
126
127char *
128ether_ntoa(const struct ether_addr *n)
129{
130	static char a[18];
131
132	return (ether_ntoa_r(n, a));
133}
134
135/*
136 * Map an ethernet address to a hostname. Use either /etc/ethers or NIS/YP.
137 */
138int
139ether_ntohost(char *hostname, const struct ether_addr *e)
140{
141	FILE *fp;
142	char buf[BUFSIZ + 2];
143	struct ether_addr local_ether;
144	char local_host[MAXHOSTNAMELEN];
145#ifdef YP
146	char *result;
147	int resultlen;
148	char *ether_a;
149	char *yp_domain;
150#endif
151
152	if ((fp = fopen(_PATH_ETHERS, "re")) == NULL)
153		return (1);
154	while (fgets(buf,BUFSIZ,fp)) {
155		if (buf[0] == '#')
156			continue;
157#ifdef YP
158		if (buf[0] == '+') {
159			if (yp_get_default_domain(&yp_domain))
160				continue;
161			ether_a = ether_ntoa(e);
162			if (yp_match(yp_domain, "ethers.byaddr", ether_a,
163			    strlen(ether_a), &result, &resultlen)) {
164				continue;
165			}
166			strncpy(buf, result, resultlen);
167			buf[resultlen] = '\0';
168			free(result);
169		}
170#endif
171		if (!ether_line(buf, &local_ether, local_host)) {
172			if (!bcmp((char *)&local_ether.octet[0],
173			    (char *)&e->octet[0], 6)) {
174				/* We have a match. */
175				strcpy(hostname, local_host);
176				fclose(fp);
177				return(0);
178			}
179		}
180	}
181	fclose(fp);
182	return (1);
183}
184
185/*
186 * Map a hostname to an ethernet address using /etc/ethers or NIS/YP.
187 */
188int
189ether_hostton(const char *hostname, struct ether_addr *e)
190{
191	FILE *fp;
192	char buf[BUFSIZ + 2];
193	struct ether_addr local_ether;
194	char local_host[MAXHOSTNAMELEN];
195#ifdef YP
196	char *result;
197	int resultlen;
198	char *yp_domain;
199#endif
200
201	if ((fp = fopen(_PATH_ETHERS, "re")) == NULL)
202		return (1);
203	while (fgets(buf,BUFSIZ,fp)) {
204		if (buf[0] == '#')
205			continue;
206#ifdef YP
207		if (buf[0] == '+') {
208			if (yp_get_default_domain(&yp_domain))
209				continue;
210			if (yp_match(yp_domain, "ethers.byname", hostname,
211			    strlen(hostname), &result, &resultlen)) {
212				continue;
213			}
214			strncpy(buf, result, resultlen);
215			buf[resultlen] = '\0';
216			free(result);
217		}
218#endif
219		if (!ether_line(buf, &local_ether, local_host)) {
220			if (!strcmp(hostname, local_host)) {
221				/* We have a match. */
222				bcopy((char *)&local_ether.octet[0],
223				    (char *)&e->octet[0], 6);
224				fclose(fp);
225				return(0);
226			}
227		}
228	}
229	fclose(fp);
230	return (1);
231}
232