1 /* $NetBSD: if_indextoname.c,v 1.4 2000/11/24 08:21:12 itojun Exp $ */ 2 /* $KAME: if_indextoname.c,v 1.7 2000/11/08 03:09:30 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 1.4 2000/11/24 08:21:12 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 #include <errno.h> 43 44 #ifdef __weak_alias 45 __weak_alias(if_indextoname,_if_indextoname) 46 #endif 47 48 /* 49 * From RFC 2533: 50 * 51 * The second function maps an interface index into its corresponding 52 * name. 53 * 54 * #include <net/if.h> 55 * 56 * char *if_indextoname(unsigned int ifindex, char *ifname); 57 * 58 * The ifname argument must point to a buffer of at least IF_NAMESIZE 59 * bytes into which the interface name corresponding to the specified 60 * index is returned. (IF_NAMESIZE is also defined in <net/if.h> and 61 * its value includes a terminating null byte at the end of the 62 * interface name.) This pointer is also the return value of the 63 * function. If there is no interface corresponding to the specified 64 * index, NULL is returned, and errno is set to ENXIO, if there was a 65 * system error (such as running out of memory), if_indextoname returns 66 * NULL and errno would be set to the proper value (e.g., ENOMEM). 67 */ 68 69 char * 70 if_indextoname(unsigned int ifindex, char *ifname) 71 { 72 struct ifaddrs *ifaddrs, *ifa; 73 int error = 0; 74 75 if (getifaddrs(&ifaddrs) < 0) 76 return(NULL); /* getifaddrs properly set errno */ 77 78 for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) { 79 if (ifa->ifa_addr && 80 ifa->ifa_addr->sa_family == AF_LINK && 81 ifindex == ((struct sockaddr_dl*) 82 (void *)ifa->ifa_addr)->sdl_index) 83 break; 84 } 85 86 if (ifa == NULL) { 87 error = ENXIO; 88 ifname = NULL; 89 } 90 else 91 strncpy(ifname, ifa->ifa_name, IFNAMSIZ); 92 93 freeifaddrs(ifaddrs); 94 95 errno = error; 96 return(ifname); 97 } 98