1 /* $KAME: if_nametoindex.c,v 1.6 2000/11/24 08:18:54 itojun Exp $ */ 2 3 /*- 4 * SPDX-License-Identifier: BSD-1-Clause 5 * 6 * Copyright (c) 1997, 2000 7 * Berkeley Software Design, Inc. All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 15 * THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL Berkeley Software Design, Inc. BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 * 27 * BSDI Id: if_nametoindex.c,v 2.3 2000/04/17 22:38:05 dab Exp 28 */ 29 30 #include "namespace.h" 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 #include <unistd.h> 41 #include "un-namespace.h" 42 43 /* 44 * From RFC 2553: 45 * 46 * 4.1 Name-to-Index 47 * 48 * 49 * The first function maps an interface name into its corresponding 50 * index. 51 * 52 * #include <net/if.h> 53 * 54 * unsigned int if_nametoindex(const char *ifname); 55 * 56 * If the specified interface name does not exist, the return value is 57 * 0, and errno is set to ENXIO. If there was a system error (such as 58 * running out of memory), the return value is 0 and errno is set to the 59 * proper value (e.g., ENOMEM). 60 */ 61 62 unsigned int 63 if_nametoindex(const char *ifname) 64 { 65 int s; 66 struct ifreq ifr; 67 struct ifaddrs *ifaddrs, *ifa; 68 unsigned int ni; 69 70 s = _socket(AF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0); 71 if (s != -1) { 72 memset(&ifr, 0, sizeof(ifr)); 73 strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name)); 74 if (_ioctl(s, SIOCGIFINDEX, &ifr) != -1) { 75 _close(s); 76 return (ifr.ifr_index); 77 } 78 _close(s); 79 } 80 81 if (getifaddrs(&ifaddrs) < 0) 82 return(0); 83 84 ni = 0; 85 86 for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) { 87 if (ifa->ifa_addr && 88 ifa->ifa_addr->sa_family == AF_LINK && 89 strcmp(ifa->ifa_name, ifname) == 0) { 90 ni = LLINDEX((struct sockaddr_dl*)ifa->ifa_addr); 91 break; 92 } 93 } 94 95 freeifaddrs(ifaddrs); 96 if (!ni) 97 errno = ENXIO; 98 return(ni); 99 } 100