/*--------------------------------*-C-*---------------------------------*
 * File:	netdisp.c
 *
 * support for resolving the actual IP number of the host for remote
 * DISPLAYs.  When the display is local (i.e. :0), we add support for
 * sending the first non-loopback interface IP number as the DISPLAY
 * instead of just sending the incorrect ":0".  This way telnet/rlogin
 * shells can actually get the correct information into DISPLAY for
 * xclients.
 *
 * Copyright 1996	Chuck Blake <cblake@BBN.COM>
 *
 * You can do what you like with this source code as long as you don't try
 * to make money out of it and you include an unaltered copy of this
 * message (including the copyright).
 *
 * As usual, the author accepts no responsibility for anything, nor does
 * he guarantee anything whatsoever.
 *----------------------------------------------------------------------*/
#include <config.h>
#include "feature.h"

/* compile an empty file if this option is disabled. */
#ifndef DISPLAY_IS_IP
/* char * network_display (const char * display) { return display; } */
#else	/* DISPLAY_IS_IP */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#ifdef HAVE_FCNTL_H
# include <fcntl.h>
#endif
#ifdef HAVE_UNISTD_H
# include <unistd.h>
#endif

/* On Solaris link with -lsocket and -lnsl */
#include <sys/types.h>
#include <sys/socket.h>

/* these next two are probably only on Sun (not Solaris) */
#ifdef HAVE_SYS_SOCKIO_H
# include <sys/sockio.h>
#endif
#ifdef HAVE_SYS_BYTEORDER_H
# include <sys/byteorder.h>
#endif

#ifdef TIME_WITH_SYS_TIME
# include <sys/time.h>
# include <time.h>
#else
# ifdef HAVE_SYS_TIME_H
#  include <sys/time.h>
# else
#  include <time.h>
# endif
#endif

#ifdef HAVE_SYS_IOCTL_H
# include <sys/ioctl.h>
#endif

#include <netinet/in.h>
#include <arpa/inet.h>
#include <net/if.h>
#include <net/if_arp.h>

/*----------------------------------------------------------------------*
 * extern functions referenced
 */
/*----------------------------------------------------------------------*
 * extern variables referenced
 */
/*----------------------------------------------------------------------*
 * extern variables declared here
 */
/*----------------------------------------------------------------------*
 * local variables
 */
/*----------------------------------------------------------------------*
 * local functions referenced
 */

/*----------------------------------------------------------------------*/
char *
network_display (const char * display)
{
   char buffer [1024], *rval = NULL;
   struct ifconf ifc;
   struct ifreq *ifr;
   int i, skfd;

   if (display [0] != ':' && strncmp (display, "unix:", 5) != 0)
     return display;		/* nothing to do */

   ifc.ifc_len = sizeof(buffer);    /* Get names of all ifaces */
   ifc.ifc_buf = buffer;

   if ((skfd = socket (AF_INET, SOCK_DGRAM, 0)) < 0)
     {
	perror ("socket");
	return NULL;
     }
   if (ioctl (skfd, SIOCGIFCONF, &ifc) < 0)
     {
	perror ("SIOCGIFCONF");
	close (skfd);
	return NULL;
     }

   for (i = 0, ifr = ifc.ifc_req;
	i < (ifc.ifc_len / sizeof(struct ifreq));
	i++, ifr++)
     {
	struct ifreq ifr2;
	strcpy (ifr2.ifr_name, ifr->ifr_name);
	if (ioctl (skfd, SIOCGIFADDR, &ifr2) >= 0)
	  {
	     unsigned long addr;
	     struct sockaddr_in *p_addr;
	     p_addr = (struct sockaddr_in *) &(ifr2.ifr_addr);
	     addr = htonl ((unsigned long) p_addr->sin_addr.s_addr);

	     /*
	      * not "0.0.0.0" or "127.0.0.1" - so format the address
	      */
	     if (addr && addr != 0x7F000001)
	       {
		  char * colon;
		  if ((colon = strchr (display, ':')) == NULL)
		    colon = ":0.0";

		  sprintf (buffer, "%d.%d.%d.%d%s",
			   (int) ((addr >> 030) & 0xFF),
			   (int) ((addr >> 020) & 0xFF),
			   (int) ((addr >> 010) & 0xFF),
			   (int) ( addr         & 0xFF), colon);

		  rval = malloc (strlen (buffer) + 1);
		  if (rval != NULL)
		    strcpy (rval, buffer);
		  break;
	       }
	  }
     }

   close (skfd);
   return rval;
}
#endif /* DISPLAY_IS_IP */
/*----------------------- end-of-file (C source) -----------------------*/