get_myaddress.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 0
  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 <net/if.h>
  48 #include <sys/ioctl.h>
  49 /* Order of following two #includes reversed by roland@gnu */
  50 #include <netinet/in.h>
  51 #include <arpa/inet.h>
  52
  53
  54 /*
  55  * don't use gethostbyname, which would invoke yellow pages
  56  *
  57  * Avoid loopback interfaces.  We return information from a loopback
  58  * interface only if there are no other possible interfaces.
  59  */
  60 void
  61 get_myaddress (struct sockaddr_in *addr)
  62 {
  63   int s;
  64   char buf[BUFSIZ];
  65   struct ifconf ifc;
  66   struct ifreq ifreq, *ifr;
  67   int len, loopback = 0;
  68
  69   if ((s = socket (AF_INET, SOCK_DGRAM, 0)) < 0)
  70     {
  71       perror ("get_myaddress: socket");
  72       exit (1);
  73     }
  74   ifc.ifc_len = sizeof (buf);
  75   ifc.ifc_buf = buf;
  76   if (ioctl (s, SIOCGIFCONF, (char *) &ifc) < 0)
  77     {
  78       perror (_("get_myaddress: ioctl (get interface configuration)"));
  79       exit (1);
  80     }
  81
  82  again:
  83   ifr = ifc.ifc_req;
  84   for (len = ifc.ifc_len; len; len -= sizeof ifreq)
  85     {
  86       ifreq = *ifr;
  87       if (ioctl (s, SIOCGIFFLAGS, (char *) &ifreq) < 0)
  88         {
  89           perror ("get_myaddress: ioctl");
  90           exit (1);
  91         }
  92       if ((ifreq.ifr_flags & IFF_UP) && (ifr->ifr_addr.sa_family == AF_INET)
  93           && (!(ifreq.ifr_flags & IFF_LOOPBACK) ||
  94               (loopback == 1 && (ifreq.ifr_flags & IFF_LOOPBACK))))
  95         {
  96           *addr = *((struct sockaddr_in *) &ifr->ifr_addr);
  97           addr->sin_port = htons (PMAPPORT);
  98           close (s);
  99           return;
 100         }
 101       ifr++;
 102     }
 103   if (loopback == 0)
 104     {
 105       loopback = 1;
 106       goto again;
 107     }
 108   close (s);
 109 }