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 #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
63 unsigned int
if_nametoindex(const char * ifname)64 if_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 memset(&ifr, 0, sizeof(ifr));
74 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
75 if (_ioctl(s, SIOCGIFINDEX, &ifr) != -1) {
76 _close(s);
77 return (ifr.ifr_index);
78 }
79 _close(s);
80 }
81
82 if (getifaddrs(&ifaddrs) < 0)
83 return(0);
84
85 ni = 0;
86
87 for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
88 if (ifa->ifa_addr &&
89 ifa->ifa_addr->sa_family == AF_LINK &&
90 strcmp(ifa->ifa_name, ifname) == 0) {
91 ni = LLINDEX((struct sockaddr_dl*)ifa->ifa_addr);
92 break;
93 }
94 }
95
96 freeifaddrs(ifaddrs);
97 if (!ni)
98 errno = ENXIO;
99 return(ni);
100 }
101