1 /* $NetBSD: if_nametoindex.c,v 1.6 2018/08/22 03:12:31 msaitoh Exp $ */ 2 /* $KAME: if_nametoindex.c,v 1.6 2000/11/24 08:18:54 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/cdefs.h> 30 #if defined(LIBC_SCCS) && !defined(lint) 31 __RCSID("$NetBSD: if_nametoindex.c,v 1.6 2018/08/22 03:12:31 msaitoh Exp $"); 32 #endif /* LIBC_SCCS and not lint */ 33 34 #ifndef RUMP_ACTION 35 #include "namespace.h" 36 #endif 37 #include <sys/types.h> 38 #include <sys/ioctl.h> 39 #include <sys/socket.h> 40 #include <net/if.h> 41 #include <net/if_dl.h> 42 #include <ifaddrs.h> 43 #include <stdlib.h> 44 #include <string.h> 45 #include <unistd.h> 46 #include <errno.h> 47 48 #ifndef RUMP_ACTION 49 #ifdef __weak_alias 50 __weak_alias(if_nametoindex,_if_nametoindex) 51 #endif 52 #endif 53 54 /* 55 * From RFC 2553: 56 * 57 * 4.1 Name-to-Index 58 * 59 * 60 * The first function maps an interface name into its corresponding 61 * index. 62 * 63 * #include <net/if.h> 64 * 65 * unsigned int if_nametoindex(const char *ifname); 66 * 67 * If the specified interface name does not exist, the return value is 68 * 0, and errno is set to ENXIO. If there was a system error (such as 69 * running out of memory), the return value is 0 and errno is set to the 70 * proper value (e.g., ENOMEM). 71 */ 72 73 unsigned int 74 if_nametoindex(const char *ifname) 75 { 76 int s; 77 struct ifreq ifr; 78 struct ifaddrs *ifaddrs, *ifa; 79 unsigned int ni; 80 81 s = socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0); 82 if (s != -1) { 83 memset(&ifr, 0, sizeof(ifr)); 84 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)); 85 if (ioctl(s, SIOCGIFINDEX, &ifr) != -1) { 86 close(s); 87 return (ifr.ifr_index); 88 } 89 close(s); 90 } 91 92 if (getifaddrs(&ifaddrs) < 0) 93 return 0; 94 95 ni = 0; 96 97 for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) { 98 if (ifa->ifa_addr && 99 ifa->ifa_addr->sa_family == AF_LINK && 100 strcmp(ifa->ifa_name, ifname) == 0) { 101 ni = ((struct sockaddr_dl*) 102 (void *)ifa->ifa_addr)->sdl_index; 103 break; 104 } 105 } 106 107 freeifaddrs(ifaddrs); 108 if (!ni) 109 errno = ENXIO; 110 return ni; 111 } 112