1 /* $NetBSD: if_nametoindex.c,v 1.6 2018/08/22 03:12:31 msaitoh Exp $ */
2 /* $KAME: if_nametoindex.c,v 1.6 2000/11/24 08:18:54 itojun Exp $ */
3
4 /*-
5 * Copyright (c) 1997, 2000
6 * Berkeley Software Design, Inc. 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 *
14 * THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL Berkeley Software Design, Inc. BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 *
26 * BSDI Id: if_nametoindex.c,v 2.3 2000/04/17 22:38:05 dab Exp
27 */
28
29 #include <sys/cdefs.h>
30 #if defined(LIBC_SCCS) && !defined(lint)
31 __RCSID("$NetBSD: if_nametoindex.c,v 1.6 2018/08/22 03:12:31 msaitoh Exp $");
32 #endif /* LIBC_SCCS and not lint */
33
34 #ifndef RUMP_ACTION
35 #include "namespace.h"
36 #endif
37 #include <sys/types.h>
38 #include <sys/ioctl.h>
39 #include <sys/socket.h>
40 #include <net/if.h>
41 #include <net/if_dl.h>
42 #include <ifaddrs.h>
43 #include <stdlib.h>
44 #include <string.h>
45 #include <unistd.h>
46 #include <errno.h>
47
48 #ifndef RUMP_ACTION
49 #ifdef __weak_alias
__weak_alias(if_nametoindex,_if_nametoindex)50 __weak_alias(if_nametoindex,_if_nametoindex)
51 #endif
52 #endif
53
54 /*
55 * From RFC 2553:
56 *
57 * 4.1 Name-to-Index
58 *
59 *
60 * The first function maps an interface name into its corresponding
61 * index.
62 *
63 * #include <net/if.h>
64 *
65 * unsigned int if_nametoindex(const char *ifname);
66 *
67 * If the specified interface name does not exist, the return value is
68 * 0, and errno is set to ENXIO. If there was a system error (such as
69 * running out of memory), the return value is 0 and errno is set to the
70 * proper value (e.g., ENOMEM).
71 */
72
73 unsigned int
74 if_nametoindex(const char *ifname)
75 {
76 int s;
77 struct ifreq ifr;
78 struct ifaddrs *ifaddrs, *ifa;
79 unsigned int ni;
80
81 s = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
82 if (s != -1) {
83 memset(&ifr, 0, sizeof(ifr));
84 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
85 if (ioctl(s, SIOCGIFINDEX, &ifr) != -1) {
86 close(s);
87 return (ifr.ifr_index);
88 }
89 close(s);
90 }
91
92 if (getifaddrs(&ifaddrs) < 0)
93 return 0;
94
95 ni = 0;
96
97 for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
98 if (ifa->ifa_addr &&
99 ifa->ifa_addr->sa_family == AF_LINK &&
100 strcmp(ifa->ifa_name, ifname) == 0) {
101 ni = ((struct sockaddr_dl*)
102 (void *)ifa->ifa_addr)->sdl_index;
103 break;
104 }
105 }
106
107 freeifaddrs(ifaddrs);
108 if (!ni)
109 errno = ENXIO;
110 return ni;
111 }
112