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