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/* $OpenBSD: if_nametoindex.c,v 1.8 2002/03/07 22:40:23 millert Exp $ */
/* $KAME: if_nametoindex.c,v 1.5 2000/11/24 08:04:40 itojun Exp $ */
/*-
* Copyright (c) 1997, 2000
* Berkeley Software Design, Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL Berkeley Software Design, Inc. BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* BSDI Id: if_nametoindex.c,v 2.3 2000/04/17 22:38:05 dab Exp
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <ifaddrs.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
/*
* From RFC 2553:
*
* 4.1 Name-to-Index
*
*
* The first function maps an interface name into its corresponding
* index.
*
* #include <net/if.h>
*
* unsigned int if_nametoindex(const char *ifname);
*
* If the specified interface name does not exist, the return value is
* 0, and errno is set to ENXIO. If there was a system error (such as
* running out of memory), the return value is 0 and errno is set to the
* proper value (e.g., ENOMEM).
*/
unsigned int
if_nametoindex(const char *ifname)
{
struct ifaddrs *ifaddrs, *ifa;
unsigned int ni;
if (getifaddrs(&ifaddrs) < 0)
return(0);
ni = 0;
for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
if (ifa->ifa_addr &&
ifa->ifa_addr->sa_family == AF_LINK &&
strcmp(ifa->ifa_name, ifname) == 0) {
ni = ((struct sockaddr_dl*)ifa->ifa_addr)->sdl_index;
break;
}
}
freeifaddrs(ifaddrs);
if (!ni)
errno = ENXIO;
return(ni);
}
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