sunrpc/get_myaddr.c

   1 /*
   2  * get_myaddress.c
   3  *
   4  * Get client's IP address via ioctl.  This avoids using the yellowpages.
   5  * Copyright (c) 2010, Oracle America, Inc.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions are
   9  * met:
  10  *
  11  *     * Redistributions of source code must retain the above copyright
  12  *       notice, this list of conditions and the following disclaimer.
  13  *     * Redistributions in binary form must reproduce the above
  14  *       copyright notice, this list of conditions and the following
  15  *       disclaimer in the documentation and/or other materials
  16  *       provided with the distribution.
  17  *     * Neither the name of the "Oracle America, Inc." nor the names of its
  18  *       contributors may be used to endorse or promote products derived
  19  *       from this software without specific prior written permission.
  20  *
  21  *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  *   FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  25  *   COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
  26  *   INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  *   DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
  28  *   GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  29  *   INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  30  *   WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
  31  *   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  32  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  33  */
  34
  35 #include <rpc/types.h>
  36 #include <rpc/clnt.h>
  37 #include <rpc/pmap_prot.h>
  38 #include <sys/socket.h>
  39 #include <stdio.h>
  40 #include <unistd.h>
  41 #include <libintl.h>
  42 #include <net/if.h>
  43 #include <ifaddrs.h>
  44 #include <sys/ioctl.h>
  45 /* Order of following two #includes reversed by roland@gnu */
  46 #include <netinet/in.h>
  47 #include <arpa/inet.h>
  48
  49 /*
  50  * don't use gethostbyname, which would invoke yellow pages
  51  *
  52  * Avoid loopback interfaces.  We return information from a loopback
  53  * interface only if there are no other possible interfaces.
  54  */
  55 void
  56 get_myaddress (struct sockaddr_in *addr)
  57 {
  58   struct ifaddrs *ifa;
  59
  60   if (getifaddrs (&ifa) != 0)
  61     {
  62       perror ("get_myaddress: getifaddrs");
  63       exit (1);
  64     }
  65
  66   int loopback = 0;
  67   struct ifaddrs *run;
  68
  69  again:
  70   run = ifa;
  71   while (run != NULL)
  72     {
  73       if ((run->ifa_flags & IFF_UP)
  74           && run->ifa_addr != NULL
  75           && run->ifa_addr->sa_family == AF_INET
  76           && (!(run->ifa_flags & IFF_LOOPBACK)
  77               || (loopback == 1 && (run->ifa_flags & IFF_LOOPBACK))))
  78         {
  79           *addr = *((struct sockaddr_in *) run->ifa_addr);
  80           addr->sin_port = htons (PMAPPORT);
  81           goto out;
  82         }
  83
  84       run = run->ifa_next;
  85     }
  86
  87   if (loopback == 0)
  88     {
  89       loopback = 1;
  90       goto again;
  91     }
  92  out:
  93   freeifaddrs (ifa);
  94
  95   /* The function is horribly specified.  It does not return any error
  96      if no interface is up.  Probably this won't happen (at least
  97      loopback is there) but still...  */
  98 }