#!/bin/bash
#Copyright 1999-2002 William Stearns <wstearns@pobox.com>
#Released under the GPL.

#MODULE="ipip" ;		TDEV="tunl0"
MODULE="ip_gre" ;	TDEV="gre0"
OUTIF="ppp0"
TSERVER="Z.Z.Z.Z"
CLIENTREALIP="Z.Z.Z.Y"

DefaultRouteDevs="`/sbin/route -n | grep '^0\.0\.0\.0[ \t]' | awk '{print $8}' | sort | uniq`"
DefaultRouteGws="`/sbin/route -n | grep '^0\.0\.0\.0[ \t]' | awk '{print $2}' | sort | uniq`"

#if [ `echo "$DefaultRouteDevs" | wc -l` -ne 1 ]; then
#	echo Too many or few default route interfaces, exiting.
#	exit 1
#fi
#if [ `echo "$DefaultRouteGws" | wc -l` -ne 1 ]; then
#	echo Too many or few default route ips, exiting.
#	exit 1
#fi

#DESTS="${DESTS} Onetargetmachine Anothertargetmachine"
DESTS="${DESTS} 0.0.0.0/0.0.0.0"
case "$1" in
start|START)
	ssh $TSERVER CLIENTDIALIP=`ifconfig $OUTIF | grep 'inet addr' | awk '{print $2}' | sed -e 's/.*://'` /root/bin/server_tunnel start
	echo 1 >/proc/sys/net/ipv4/ip_forward
	insmod $MODULE >/dev/null 2>/dev/null
	ifconfig $TDEV $CLIENTREALIP pointopoint $TSERVER netmask 255.255.255.255 up

	route del -host $TSERVER $TDEV
	route add -host $TSERVER $TDEV
	for AHOST in $DESTS ; do
		case "$AHOST" in
		*/*)
			Network=${AHOST%%/*}
			Netmask=${AHOST##*/}
			route add -net $Network netmask $Netmask gw $TSERVER $TDEV
			if [ "$AHOST" = "0.0.0.0/0.0.0.0" ]; then
				route del default $OUTIF
			fi
			;;
		*)
			route add -host $AHOST gw $TSERVER $TDEV
			;;
		esac
	done
	route del -host $TSERVER $TDEV
	route del -host $TSERVER $TDEV >/dev/null 2>/dev/null

	route add -host $TSERVER $OUTIF
	;;

stop|STOP)
	route del -host $TSERVER $OUTIF

	for AHOST in $DESTS ; do
		case "$AHOST" in
		*/*)
			Network=${AHOST%%/*}
			Netmask=${AHOST##*/}
			#echo "Routing to network $Network, netmask $Netmask"
			route del -net $Network netmask $Netmask gw $TSERVER $TDEV
			if [ "$AHOST" = "0.0.0.0/0.0.0.0" ]; then
				route add default $OUTIF
			fi
			;;
		*)
			route del -host $AHOST gw $TSERVER $TDEV
			;;
		esac
	done

	ifconfig $TDEV down
	#route add default $OUTIF	#Done above
	rmmod ip_gre
	ssh $TSERVER /root/bin/server_tunnel stop
	;;
*)
	echo Use \"$0 start\" or \"$0 stop\".
	;;
esac