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/cdefs.h> 29 __FBSDID("$FreeBSD$"); 30 31 #include <sys/types.h> 32 #include <sys/socket.h> 33 #include <sys/sockio.h> 34 #include <net/if.h> 35 #include <net/if_dl.h> 36 #include <ifaddrs.h> 37 #include <stdlib.h> 38 #include <string.h> 39 #include <errno.h> 40 41 /* 42 * From RFC 2553: 43 * 44 * 4.1 Name-to-Index 45 * 46 * 47 * The first function maps an interface name into its corresponding 48 * index. 49 * 50 * #include <net/if.h> 51 * 52 * unsigned int if_nametoindex(const char *ifname); 53 * 54 * If the specified interface name does not exist, the return value is 55 * 0, and errno is set to ENXIO. If there was a system error (such as 56 * running out of memory), the return value is 0 and errno is set to the 57 * proper value (e.g., ENOMEM). 58 */ 59 60 unsigned int 61 if_nametoindex(const char *ifname) 62 { 63 int s; 64 struct ifreq ifr; 65 struct ifaddrs *ifaddrs, *ifa; 66 unsigned int ni; 67 68 s = _socket(AF_INET, SOCK_DGRAM, 0); 69 if (s != -1) { 70 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)); 71 if (_ioctl(s, SIOCGIFINDEX, &ifr) != -1) { 72 _close(s); 73 return (ifr.ifr_index); 74 } 75 _close(s); 76 } 77 78 if (getifaddrs(&ifaddrs) < 0) 79 return(0); 80 81 ni = 0; 82 83 for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) { 84 if (ifa->ifa_addr && 85 ifa->ifa_addr->sa_family == AF_LINK && 86 strcmp(ifa->ifa_name, ifname) == 0) { 87 ni = ((struct sockaddr_dl*)ifa->ifa_addr)->sdl_index; 88 break; 89 } 90 } 91 92 freeifaddrs(ifaddrs); 93 if (!ni) 94 errno = ENXIO; 95 return(ni); 96 } 97