sunrpc/get_myaddr.c

   1 /* @(#)get_myaddress.c 2.1 88/07/29 4.0 RPCSRC */
   2 /*
   3  * Sun RPC is a product of Sun Microsystems, Inc. and is provided for
   4  * unrestricted use provided that this legend is included on all tape
   5  * media and as a part of the software program in whole or part.  Users
   6  * may copy or modify Sun RPC without charge, but are not authorized
   7  * to license or distribute it to anyone else except as part of a product or
   8  * program developed by the user.
   9  *
  10  * SUN RPC IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING THE
  11  * WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
  12  * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
  13  *
  14  * Sun RPC is provided with no support and without any obligation on the
  15  * part of Sun Microsystems, Inc. to assist in its use, correction,
  16  * modification or enhancement.
  17  *
  18  * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
  19  * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY SUN RPC
  20  * OR ANY PART THEREOF.
  21  *
  22  * In no event will Sun Microsystems, Inc. be liable for any lost revenue
  23  * or profits or other special, indirect and consequential damages, even if
  24  * Sun has been advised of the possibility of such damages.
  25  *
  26  * Sun Microsystems, Inc.
  27  * 2550 Garcia Avenue
  28  * Mountain View, California  94043
  29  */
  30 #if !defined(lint) && defined(SCCSIDS)
  31 static char sccsid[] = "@(#)get_myaddress.c 1.4 87/08/11 Copyr 1984 Sun Micro";
  32 #endif
  33
  34 /*
  35  * get_myaddress.c
  36  *
  37  * Get client's IP address via ioctl.  This avoids using the yellowpages.
  38  * Copyright (C) 1984, Sun Microsystems, Inc.
  39  */
  40
  41 #include <rpc/types.h>
  42 #include <rpc/clnt.h>
  43 #include <rpc/pmap_prot.h>
  44 #include <sys/socket.h>
  45 #include <stdio.h>
  46 #include <unistd.h>
  47 #include <libintl.h>
  48 #include <net/if.h>
  49 #include <ifaddrs.h>
  50 #include <sys/ioctl.h>
  51 /* Order of following two #includes reversed by roland@gnu */
  52 #include <netinet/in.h>
  53 #include <arpa/inet.h>
  54
  55 /*
  56  * don't use gethostbyname, which would invoke yellow pages
  57  *
  58  * Avoid loopback interfaces.  We return information from a loopback
  59  * interface only if there are no other possible interfaces.
  60  */
  61 void
  62 get_myaddress (struct sockaddr_in *addr)
  63 {
  64   struct ifaddrs *ifa;
  65
  66   if (getifaddrs (&ifa) != 0)
  67     {
  68       perror ("get_myaddress: getifaddrs");
  69       exit (1);
  70     }
  71
  72   int loopback = 0;
  73   struct ifaddrs *run;
  74
  75  again:
  76   run = ifa;
  77   while (run != NULL)
  78     {
  79       if ((run->ifa_flags & IFF_UP)
  80           && run->ifa_addr != NULL
  81           && run->ifa_addr->sa_family == AF_INET
  82           && (!(run->ifa_flags & IFF_LOOPBACK)
  83               || (loopback == 1 && (run->ifa_flags & IFF_LOOPBACK))))
  84         {
  85           *addr = *((struct sockaddr_in *) run->ifa_addr);
  86           addr->sin_port = htons (PMAPPORT);
  87           goto out;
  88         }
  89
  90       run = run->ifa_next;
  91     }
  92
  93   if (loopback == 0)
  94     {
  95       loopback = 1;
  96       goto again;
  97     }
  98  out:
  99   freeifaddrs (ifa);
 100
 101   /* The function is horribly specified.  It does not return any error
 102      if no interface is up.  Probably this won't happen (at least
 103      loopback is there) but still...  */
 104 }