1/*	$KAME: if_nametoindex.c,v 1.6 2000/11/24 08:18:54 itojun Exp $	*/
2
3/*-
4 * Copyright (c) 1997, 2000
5 *	Berkeley Software Design, Inc.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 *
13 * THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``AS IS'' AND
14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16 * ARE DISCLAIMED.  IN NO EVENT SHALL Berkeley Software Design, Inc. BE LIABLE
17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
23 * SUCH DAMAGE.
24 *
25 *	BSDI Id: if_nametoindex.c,v 2.3 2000/04/17 22:38:05 dab Exp
26 */
27
28#include <sys/cdefs.h>
29__FBSDID("$FreeBSD$");
30
31#include "namespace.h"
32#include <sys/types.h>
33#include <sys/socket.h>
34#include <sys/sockio.h>
35#include <net/if.h>
36#include <net/if_dl.h>
37#include <ifaddrs.h>
38#include <stdlib.h>
39#include <string.h>
40#include <errno.h>
41#include <unistd.h>
42#include "un-namespace.h"
43
44/*
45 * From RFC 2553:
46 *
47 * 4.1 Name-to-Index
48 *
49 *
50 *    The first function maps an interface name into its corresponding
51 *    index.
52 *
53 *       #include <net/if.h>
54 *
55 *       unsigned int  if_nametoindex(const char *ifname);
56 *
57 *    If the specified interface name does not exist, the return value is
58 *    0, and errno is set to ENXIO.  If there was a system error (such as
59 *    running out of memory), the return value is 0 and errno is set to the
60 *    proper value (e.g., ENOMEM).
61 */
62
63unsigned int
64if_nametoindex(const char *ifname)
65{
66	int s;
67	struct ifreq ifr;
68	struct ifaddrs *ifaddrs, *ifa;
69	unsigned int ni;
70
71	s = _socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
72	if (s != -1) {
73#ifdef PURIFY
74		memset(&ifr, 0, sizeof(ifr));
75#endif
76		strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
77		if (_ioctl(s, SIOCGIFINDEX, &ifr) != -1) {
78			_close(s);
79			return (ifr.ifr_index);
80		}
81		_close(s);
82	}
83
84	if (getifaddrs(&ifaddrs) < 0)
85		return(0);
86
87	ni = 0;
88
89	for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
90		if (ifa->ifa_addr &&
91		    ifa->ifa_addr->sa_family == AF_LINK &&
92		    strcmp(ifa->ifa_name, ifname) == 0) {
93			ni = LLINDEX((struct sockaddr_dl*)ifa->ifa_addr);
94			break;
95		}
96	}
97
98	freeifaddrs(ifaddrs);
99	if (!ni)
100		errno = ENXIO;
101	return(ni);
102}
103