gen.subproj/if_nametoindex.c

   1 /*
   2  * Copyright (c) 2018 Apple Inc. All rights reserved.
   3  */
   4 /*      $KAME: if_nametoindex.c,v 1.6 2000/11/24 08:18:54 itojun Exp $  */
   5
   6 /*-
   7  * Copyright (c) 1997, 2000
   8  *      Berkeley Software Design, Inc.  All rights reserved.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL Berkeley Software Design, Inc. BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  *
  28  *      BSDI Id: if_nametoindex.c,v 2.3 2000/04/17 22:38:05 dab Exp
  29  */
  30
  31 #include "libinfo_common.h"
  32
  33 #include <sys/types.h>
  34 #include <sys/socket.h>
  35 #include <net/if.h>
  36 #include <net/if_dl.h>
  37 #include <ifaddrs.h>
  38 #include <stdlib.h>
  39 #include <string.h>
  40 #include <errno.h>
  41
  42 /*
  43  * From RFC 2553:
  44  *
  45  * 4.1 Name-to-Index
  46  *
  47  *
  48  *    The first function maps an interface name into its corresponding
  49  *    index.
  50  *
  51  *       #include <net/if.h>
  52  *
  53  *       unsigned int  if_nametoindex(const char *ifname);
  54  *
  55  *    If the specified interface name does not exist, the return value is
  56  *    0, and errno is set to ENXIO.  If there was a system error (such as
  57  *    running out of memory), the return value is 0 and errno is set to the
  58  *    proper value (e.g., ENOMEM).
  59  */
  60
  61 LIBINFO_EXPORT
  62 unsigned int
  63 if_nametoindex(const char *ifname)
  64 {
  65         struct ifaddrs *ifaddrs, *ifa;
  66         unsigned int ni;
  67
  68         if (getifaddrs(&ifaddrs) < 0)
  69                 return(0);
  70
  71         ni = 0;
  72
  73         for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
  74                 if (ifa->ifa_addr &&
  75                     ifa->ifa_addr->sa_family == AF_LINK &&
  76                     strcmp(ifa->ifa_name, ifname) == 0) {
  77                         ni = ((struct sockaddr_dl*)ifa->ifa_addr)->sdl_index;
  78                         break;
  79                 }
  80         }
  81
  82         freeifaddrs(ifaddrs);
  83         if (!ni)
  84                 errno = ENXIO;
  85         return(ni);
  86 }