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 * $FreeBSD: src/lib/libc/net/if_nametoindex.c,v 1.5 2003/05/01 19:03:14 nectar Exp $
27 * $DragonFly: src/lib/libc/net/if_nametoindex.c,v 1.2 2003/06/17 04:26:44 dillon Exp $
28 */
29
30 #include "namespace.h"
31 #include <sys/types.h>
32 #include <sys/socket.h>
33 #include <sys/sockio.h>
34 #include <net/if.h>
35 #include <net/if_dl.h>
36 #include <ifaddrs.h>
37 #include <stdlib.h>
38 #include <string.h>
39 #include <errno.h>
40 #include <unistd.h>
41 #include "un-namespace.h"
42
43 /*
44 * From RFC 2553:
45 *
46 * 4.1 Name-to-Index
47 *
48 *
49 * The first function maps an interface name into its corresponding
50 * index.
51 *
52 * #include <net/if.h>
53 *
54 * unsigned int if_nametoindex(const char *ifname);
55 *
56 * If the specified interface name does not exist, the return value is
57 * 0, and errno is set to ENXIO. If there was a system error (such as
58 * running out of memory), the return value is 0 and errno is set to the
59 * proper value (e.g., ENOMEM).
60 */
61
62 unsigned int
if_nametoindex(const char * ifname)63 if_nametoindex(const char *ifname)
64 {
65 int s;
66 struct ifreq ifr;
67 struct ifaddrs *ifaddrs, *ifa;
68 unsigned int ni;
69
70 s = _socket(AF_INET, SOCK_DGRAM, 0);
71 if (s != -1) {
72 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
73 if (_ioctl(s, SIOCGIFINDEX, &ifr) != -1) {
74 _close(s);
75 return (ifr.ifr_index);
76 }
77 _close(s);
78 }
79
80 if (getifaddrs(&ifaddrs) < 0)
81 return(0);
82
83 ni = 0;
84
85 for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
86 if (ifa->ifa_addr &&
87 ifa->ifa_addr->sa_family == AF_LINK &&
88 strcmp(ifa->ifa_name, ifname) == 0) {
89 ni = ((struct sockaddr_dl*)ifa->ifa_addr)->sdl_index;
90 break;
91 }
92 }
93
94 freeifaddrs(ifaddrs);
95 if (!ni)
96 errno = ENXIO;
97 return(ni);
98 }
99