1 /* $KAME: if_indextoname.c,v 1.7 2000/11/08 03:09:30 itojun Exp $ */
4 * SPDX-License-Identifier: BSD-1-Clause
6 * Copyright (c) 1997, 2000
7 * Berkeley Software Design, Inc. All rights reserved.
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
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
27 * BSDI Id: if_indextoname.c,v 2.3 2000/04/17 22:38:05 dab Exp
30 #include <sys/cdefs.h>
31 __FBSDID("$FreeBSD$");
33 #include <sys/types.h>
34 #include <sys/socket.h>
35 #include <net/if_dl.h>
45 * The second function maps an interface index into its corresponding
50 * char *if_indextoname(unsigned int ifindex, char *ifname);
52 * The ifname argument must point to a buffer of at least IF_NAMESIZE
53 * bytes into which the interface name corresponding to the specified
54 * index is returned. (IF_NAMESIZE is also defined in <net/if.h> and
55 * its value includes a terminating null byte at the end of the
56 * interface name.) This pointer is also the return value of the
57 * function. If there is no interface corresponding to the specified
58 * index, NULL is returned, and errno is set to ENXIO, if there was a
59 * system error (such as running out of memory), if_indextoname returns
60 * NULL and errno would be set to the proper value (e.g., ENOMEM).
64 if_indextoname(unsigned int ifindex, char *ifname)
66 struct ifaddrs *ifaddrs, *ifa;
69 if (getifaddrs(&ifaddrs) < 0)
70 return(NULL); /* getifaddrs properly set errno */
72 for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
74 ifa->ifa_addr->sa_family == AF_LINK &&
75 ifindex == LLINDEX((struct sockaddr_dl*)ifa->ifa_addr))
84 strncpy(ifname, ifa->ifa_name, IFNAMSIZ);