1 /* $OpenBSD: if_indextoname.c,v 1.12 2018/05/10 13:44:43 tb Exp $ */
2 /* $KAME: if_indextoname.c,v 1.6 2000/11/07 22:33:25 jinmei Exp $ */
3
4 /*-
5 * Copyright (c) 2015 Claudio Jeker <claudio@openbsd.org>
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_indextoname.c,v 2.3 2000/04/17 22:38:05 dab Exp
28 */
29
30 #include <sys/types.h>
31 #include <sys/socket.h>
32 #include <net/if.h>
33 #include <stdlib.h>
34 #include <string.h>
35 #include <errno.h>
36
37 /*
38 * From RFC 2553:
39 *
40 * The second function maps an interface index into its corresponding
41 * name.
42 *
43 * #include <net/if.h>
44 *
45 * char *if_indextoname(unsigned int ifindex, char *ifname);
46 *
47 * The ifname argument must point to a buffer of at least IF_NAMESIZE
48 * bytes into which the interface name corresponding to the specified
49 * index is returned. (IF_NAMESIZE is also defined in <net/if.h> and
50 * its value includes a terminating null byte at the end of the
51 * interface name.) This pointer is also the return value of the
52 * function. If there is no interface corresponding to the specified
53 * index, NULL is returned, and errno is set to ENXIO, if there was a
54 * system error (such as running out of memory), if_indextoname returns
55 * NULL and errno would be set to the proper value (e.g., ENOMEM).
56 */
57
58 char *
if_indextoname(unsigned int ifindex,char * ifname)59 if_indextoname(unsigned int ifindex, char *ifname)
60 {
61 struct if_nameindex *ifni, *ifni2;
62
63 if ((ifni = if_nameindex()) == NULL)
64 return NULL;
65
66 for (ifni2 = ifni; ifni2->if_index != 0; ifni2++) {
67 if (ifni2->if_index == ifindex) {
68 strlcpy(ifname, ifni2->if_name, IFNAMSIZ);
69 if_freenameindex(ifni);
70 return ifname;
71 }
72 }
73
74 if_freenameindex(ifni);
75 errno = ENXIO;
76 return NULL;
77 }
78 DEF_WEAK(if_indextoname);
79