1/* $NetBSD: if_indextoname.c,v 1.6 2010/12/13 21:07:54 pooka 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 1.6 2010/12/13 21:07:54 pooka 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/socket.h> 39#include <net/if_dl.h> 40#include <net/if.h> 41#include <ifaddrs.h> 42#include <stdlib.h> 43#include <string.h> 44#include <errno.h> 45 46#ifndef RUMP_ACTION 47#ifdef __weak_alias 48__weak_alias(if_indextoname,_if_indextoname) 49#endif 50#endif 51 52/* 53 * From RFC 2533: 54 * 55 * The second function maps an interface index into its corresponding 56 * name. 57 * 58 * #include <net/if.h> 59 * 60 * char *if_indextoname(unsigned int ifindex, char *ifname); 61 * 62 * The ifname argument must point to a buffer of at least IF_NAMESIZE 63 * bytes into which the interface name corresponding to the specified 64 * index is returned. (IF_NAMESIZE is also defined in <net/if.h> and 65 * its value includes a terminating null byte at the end of the 66 * interface name.) This pointer is also the return value of the 67 * function. If there is no interface corresponding to the specified 68 * index, NULL is returned, and errno is set to ENXIO, if there was a 69 * system error (such as running out of memory), if_indextoname returns 70 * NULL and errno would be set to the proper value (e.g., ENOMEM). 71 */ 72 73char * 74if_indextoname(unsigned int ifindex, char *ifname) 75{ 76 struct ifaddrs *ifaddrs, *ifa; 77 int error = 0; 78 79 if (getifaddrs(&ifaddrs) < 0) 80 return(NULL); /* getifaddrs properly set errno */ 81 82 for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) { 83 if (ifa->ifa_addr && 84 ifa->ifa_addr->sa_family == AF_LINK && 85 ifindex == ((struct sockaddr_dl*) 86 (void *)ifa->ifa_addr)->sdl_index) 87 break; 88 } 89 90 if (ifa == NULL) { 91 error = ENXIO; 92 ifname = NULL; 93 } 94 else 95 strlcpy(ifname, ifa->ifa_name, IFNAMSIZ); 96 97 freeifaddrs(ifaddrs); 98 99 errno = error; 100 return(ifname); 101} 102