1 /* $OpenBSD: if_indextoname.c,v 1.12 2018/05/10 13:44:43 tb Exp $ */ 2 /* $KAME: if_indextoname.c,v 1.6 2000/11/07 22:33:25 jinmei Exp $ */ 3 4 /*- 5 * Copyright (c) 2015 Claudio Jeker <claudio@openbsd.org> 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_indextoname.c,v 2.3 2000/04/17 22:38:05 dab Exp 28 */ 29 30 #include <sys/types.h> 31 #include <sys/socket.h> 32 #include <net/if.h> 33 #include <stdlib.h> 34 #include <string.h> 35 #include <errno.h> 36 37 /* 38 * From RFC 2553: 39 * 40 * The second function maps an interface index into its corresponding 41 * name. 42 * 43 * #include <net/if.h> 44 * 45 * char *if_indextoname(unsigned int ifindex, char *ifname); 46 * 47 * The ifname argument must point to a buffer of at least IF_NAMESIZE 48 * bytes into which the interface name corresponding to the specified 49 * index is returned. (IF_NAMESIZE is also defined in <net/if.h> and 50 * its value includes a terminating null byte at the end of the 51 * interface name.) This pointer is also the return value of the 52 * function. If there is no interface corresponding to the specified 53 * index, NULL is returned, and errno is set to ENXIO, if there was a 54 * system error (such as running out of memory), if_indextoname returns 55 * NULL and errno would be set to the proper value (e.g., ENOMEM). 56 */ 57 58 char * 59 if_indextoname(unsigned int ifindex, char *ifname) 60 { 61 struct if_nameindex *ifni, *ifni2; 62 63 if ((ifni = if_nameindex()) == NULL) 64 return NULL; 65 66 for (ifni2 = ifni; ifni2->if_index != 0; ifni2++) { 67 if (ifni2->if_index == ifindex) { 68 strlcpy(ifname, ifni2->if_name, IFNAMSIZ); 69 if_freenameindex(ifni); 70 return ifname; 71 } 72 } 73 74 if_freenameindex(ifni); 75 errno = ENXIO; 76 return NULL; 77 } 78 DEF_WEAK(if_indextoname); 79