1/* $KAME: if_nametoindex.c,v 1.6 2000/11/24 08:18:54 itojun Exp $ */ 2 3/*- 4 * Copyright (c) 1997, 2000 5 * Berkeley Software Design, Inc. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 13 * THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``AS IS'' AND 14 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 16 * ARE DISCLAIMED. IN NO EVENT SHALL Berkeley Software Design, Inc. BE LIABLE 17 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23 * SUCH DAMAGE. 24 * 25 * BSDI Id: if_nametoindex.c,v 2.3 2000/04/17 22:38:05 dab Exp 26 */ 27 28#include <sys/types.h> 29#include <sys/socket.h> 30#include <net/if.h> 31#include <net/if_dl.h> 32#include <ifaddrs.h> 33#include <stdlib.h> 34#include <string.h> 35#include <errno.h> 36 37/* 38 * From RFC 2553: 39 * 40 * 4.1 Name-to-Index 41 * 42 * 43 * The first function maps an interface name into its corresponding 44 * index. 45 * 46 * #include <net/if.h> 47 * 48 * unsigned int if_nametoindex(const char *ifname); 49 * 50 * If the specified interface name does not exist, the return value is 51 * 0, and errno is set to ENXIO. If there was a system error (such as 52 * running out of memory), the return value is 0 and errno is set to the 53 * proper value (e.g., ENOMEM). 54 */ 55 56unsigned int 57if_nametoindex(const char *ifname) 58{ 59 struct ifaddrs *ifaddrs, *ifa; 60 unsigned int ni; 61 62 if (getifaddrs(&ifaddrs) < 0) 63 return(0); 64 65 ni = 0; 66 67 for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) { 68 if (ifa->ifa_addr && 69 ifa->ifa_addr->sa_family == AF_LINK && 70 strcmp(ifa->ifa_name, ifname) == 0) { 71 ni = ((struct sockaddr_dl*)ifa->ifa_addr)->sdl_index; 72 break; 73 } 74 } 75 76 freeifaddrs(ifaddrs); 77 if (!ni) 78 errno = ENXIO; 79 return(ni); 80} 81