1 /* $NetBSD: if_indextoname.c,v 1.2 2000/04/24 10:40:25 itojun Exp $ */ 2 /* $KAME: if_indextoname.c,v 1.4 2000/04/24 10:08:41 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_indextoname.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_indextoname.c,v 1.2 2000/04/24 10:40:25 itojun Exp $"); 32 #endif /* LIBC_SCCS and not lint */ 33 34 #include "namespace.h" 35 #include <sys/types.h> 36 #include <sys/socket.h> 37 #include <net/if_dl.h> 38 #include <net/if.h> 39 #include <ifaddrs.h> 40 #include <stdlib.h> 41 #include <string.h> 42 43 #ifdef __weak_alias 44 __weak_alias(if_indextoname,_if_indextoname) 45 #endif 46 47 /* 48 * From RFC 2133: 49 * 50 * 4.2. Index-to-Name 51 * 52 * The second function maps an interface index into its corresponding 53 * name. 54 * 55 * #include <net/if.h> 56 * 57 * char *if_indextoname(unsigned int ifindex, char *ifname); 58 * 59 * The ifname argument must point to a buffer of at least IFNAMSIZ bytes 60 * into which the interface name corresponding to the specified index is 61 * returned. (IFNAMSIZ is also defined in <net/if.h> and its value 62 * includes a terminating null byte at the end of the interface name.) 63 * This pointer is also the return value of the function. If there is 64 * no interface corresponding to the specified index, NULL is returned. 65 */ 66 67 char * 68 if_indextoname(unsigned int ifindex, char *ifname) 69 { 70 struct ifaddrs *ifaddrs, *ifa; 71 72 if (getifaddrs(&ifaddrs) < 0) 73 return(NULL); 74 75 for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) { 76 if (ifa->ifa_addr && 77 ifa->ifa_addr->sa_family == AF_LINK && 78 ifindex == ((struct sockaddr_dl*)ifa->ifa_addr)->sdl_index) 79 break; 80 } 81 82 if (ifa == NULL) 83 ifname = NULL; 84 else 85 strncpy(ifname, ifa->ifa_name, IFNAMSIZ); 86 87 freeifaddrs(ifaddrs); 88 89 return(ifname); 90 } 91