1 /* $OpenBSD: if_nametoindex.c,v 1.8 2002/03/07 22:40:23 millert Exp $ */ 2 /* $KAME: if_nametoindex.c,v 1.5 2000/11/24 08:04:40 itojun Exp $ */ 3 4 /*- 5 * Copyright (c) 1997, 2000 6 * Berkeley Software Design, Inc. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 14 * THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL Berkeley Software Design, Inc. BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * BSDI Id: if_nametoindex.c,v 2.3 2000/04/17 22:38:05 dab Exp 27 */ 28 29 #include <sys/types.h> 30 #include <sys/socket.h> 31 #include <net/if.h> 32 #include <net/if_dl.h> 33 #include <ifaddrs.h> 34 #include <stdlib.h> 35 #include <string.h> 36 #include <errno.h> 37 38 /* 39 * From RFC 2553: 40 * 41 * 4.1 Name-to-Index 42 * 43 * 44 * The first function maps an interface name into its corresponding 45 * index. 46 * 47 * #include <net/if.h> 48 * 49 * unsigned int if_nametoindex(const char *ifname); 50 * 51 * If the specified interface name does not exist, the return value is 52 * 0, and errno is set to ENXIO. If there was a system error (such as 53 * running out of memory), the return value is 0 and errno is set to the 54 * proper value (e.g., ENOMEM). 55 */ 56 57 unsigned int 58 if_nametoindex(const char *ifname) 59 { 60 struct ifaddrs *ifaddrs, *ifa; 61 unsigned int ni; 62 63 if (getifaddrs(&ifaddrs) < 0) 64 return(0); 65 66 ni = 0; 67 68 for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) { 69 if (ifa->ifa_addr && 70 ifa->ifa_addr->sa_family == AF_LINK && 71 strcmp(ifa->ifa_name, ifname) == 0) { 72 ni = ((struct sockaddr_dl*)ifa->ifa_addr)->sdl_index; 73 break; 74 } 75 } 76 77 freeifaddrs(ifaddrs); 78 if (!ni) 79 errno = ENXIO; 80 return(ni); 81 } 82