dnl
dnl  TUN - Universal TUN/TAP device driver.
dnl  Copyright (C) 1999-2000 Maxim Krasnyansky <max_mk@yahoo.com>
dnl
dnl  This program is free software; you can redistribute it and/or modify
dnl  it under the terms of the GNU General Public License as published by
dnl  the Free Software Foundation; either version 2 of the License, or
dnl  (at your option) any later version.
dnl
dnl  This program is distributed in the hope that it will be useful,
dnl  but WITHOUT ANY WARRANTY; without even the implied warranty of
dnl  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
dnl  GNU General Public License for more details.
dnl
dnl  $Id: configure.in,v 1.12 2001/02/02 03:51:35 maxk Exp $
dnl
dnl Process this file with autoconf to produce a configure script.
dnl
AC_INIT()

AC_SUBST(KDIR)
AC_SUBST(KVER)
AC_SUBST(ARCH)
AC_SUBST(UPGRADE)

AC_PROG_CC
AC_CHECK_PROG(KGCC, kgcc, kgcc, $CC)
AC_PROG_AWK
AC_PROG_INSTALL

CC=$KGCC

AC_ARG_WITH(kernel,
   --with-kernel=DIR     Kernel source location,
   KDIR="$withval",
   KDIR=/usr/src/linux
)
AC_ARG_ENABLE(debug,
   --enable-debug        Enable debuging,
   AC_DEFINE(TUN_DEBUG, 1)
)      

# Check kernel sources
AC_TEST_FILES(Makefile include/linux/if.h, $KDIR,  ,
   AC_MSG_ERROR( Linux kernel source not found in $KDIR )
)       
AC_TEST_FILES(.config include/linux/version.h, $KDIR,  ,
   AC_MSG_ERROR( Linux kernel $KDIR is not configured )
) 
      
ARCH=`uname -m | sed -e s/i.86/i386/ -e s/sun4u/sparc64/ \
      -e s/arm.*/arm/ -e s/sa110/arm/`

KVER=`cat $KDIR/Makefile | $AWK '			\
	/^VERSION.*=/    { ver=$3   }			\
        /^PATCHLEVEL.*=/ { patch=$3 }			\
        /^SUBLEVEL.*=/   { slev=$3  }			\
        /^EXTRAVER.*=/   { print ver "." patch "." slev $3 }' ` 

TDIR=`echo $KVER | cut -d '.' -f 1,2`

AC_TEST_FILES(tun.c if_tun.h, $TDIR, ,
   AC_MSG_ERROR( Unsupported kernel version. )
)

UPGRADE=0

case $TDIR in
     2.2)
 	AC_MSG_CHECKING( for new kill_fasync call )
        CPPFLAGS="$CPPFLAGS -D__KERNEL__ -I $KDIR/include"
	AC_TRY_COMPILE( 
	   [ #include <linux/fs.h> ], 
	   [ kill_fasync(NULL, 1, 1) ],
	   AC_DEFINE(NEW_FASYNC)
	   AC_MSG_RESULT("yes"),
	   AC_MSG_RESULT("no")
	)

	AC_DEFINE_UNQUOTED(TUN_VER, "$TUN_VER")
        ;;

     2.4)
 	AC_MSG_CHECKING( for kernel driver version )

 	# Check driver files 
	AC_TEST_FILES(drivers/net/tun.c include/linux/if_tun.h, $KDIR,  ,
	   AC_MSG_ERROR( Universal TUN/TAP driver was not found in $KDIR )
	)

        O_VER=`grep '#.*TUN_VER' $KDIR/drivers/net/tun.c | tr -d '\000-\057A-z'`
        N_VER=`grep '#.*TUN_VER' $TDIR/tun.c | tr -d '\000-\057A-z'`

        if test $N_VER -lt $O_VER; then
	   AC_MSG_RESULT("newer")
        elif test $N_VER -eq $O_VER; then
	   AC_MSG_RESULT("same")
        else  
           AC_MSG_RESULT("older")
	   UPGRADE=1
        fi
        ;;
esac

AC_LINK_FILES($TDIR/tun.c $TDIR/if_tun.h $TDIR/make_rules, tun.c if_tun.h make_rules)

AC_OUTPUT(Makefile)

if test $UPGRADE -eq 1; then
   AC_MSG_RESULT()
   AC_MSG_RESULT("Run 'make kernel' to upgrade kernel driver")
fi