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