#!/bin/sh

NUMBER_OF_VM=1

USERNAME=root

if [ $2 ] ; then
	NVM=$2
	let NUMBER_OF_VM=NVM-1
fi

if [ $3 ] ; then
	USERNAME=$3
fi

case "$1" in
	start)
		# Detect the gateway
		echo -n "Searching for configured gateway... "
		CURRENT_GW=`route -n | grep UG | sed s/'  *'/' '/g | cut -d' ' -f2`  
		if [ "$CURRENT_GW" ]; then
			echo "$CURRENT_GW"
		else
			echo "cannot find gateway: stop."
			exit 1;
		fi

		# Interface associated with the gateway
		CURRENT_IF=`route -n | grep UG | sed s/'  *'/' '/g | cut -d' ' -f8`  
		echo "Associated interface: $CURRENT_IF"

		# Retrieve interface configuration
		echo -n "Searching for interface address... "
		CURRENT_IP=`ifconfig $CURRENT_IF | grep 'inet addr' | cut -d: -f2 | cut -d' ' -f1`
		if [ "$CURRENT_IP" ]; then
			echo "$CURRENT_IP"
		else
			echo "cannot find address: stop."
			exit 1;
		fi

		echo "Creating the bridge: br0"
		brctl addbr br0

		echo -n "Adding interfaces:"
		NB=0
		while [ $NB -le $NUMBER_OF_VM ]
		do
			echo -n " tap$NB"
			/usr/lib/virtualbox/VBoxTunctl -t tap$NB -u $USERNAME > /dev/null
			ifconfig tap$NB up
			brctl addif br0 tap$NB

			let NB=NB+1
		done
		echo ""

		echo "Setting $CURRENT_IF in promisc mode"
		ifconfig $CURRENT_IF 0.0.0.0 promisc

		echo "Adding $CURRENT_IF to the bridge"
		brctl addif br0 $CURRENT_IF

		echo "Configuring bridge with address $CURRENT_IP"
		ifconfig br0 $CURRENT_IP
		echo "Adding route to gateway $CURRENT_GW"
		route add default gw $CURRENT_GW
		echo "Done!"
		;;

	stop)
		# Detect the gateway
		echo -n "Searching for configured gateway... "
		CURRENT_GW=`route -n | grep UG | sed s/'  *'/' '/g | cut -d' ' -f2`  
		if [ "$CURRENT_GW" ]; then
			echo "$CURRENT_GW"
		else
			echo "cannot find gateway: stop."
			exit 1;
		fi

		# Interface associated with the gateway
		CURRENT_IF=`route -n | grep UG | sed s/'  *'/' '/g | cut -d' ' -f8`  
		echo "Associated interface: $CURRENT_IF"

		if [ "$CURRENT_IF" != "br0" ]; then
			echo "Associated interface is not the bridge br0: stop."
			exit 1;
		fi

		# Retrieve interface configuration
		echo -n "Searching for bridge address... "
		CURRENT_IP=`ifconfig $CURRENT_IF | grep 'inet addr' | cut -d: -f2 | cut -d' ' -f1`
		if [ "$CURRENT_IP" ]; then
			echo "$CURRENT_IP"
		else
			echo "cannot find bridge address: stop."
			exit 1;
		fi

		IFACES=`brctl show | tail -n +2 | sed  's/\t\+/\n/g' | grep -v '^$' | tail -n +4`

		echo "Shutting down bridge br0"
		ifconfig br0 down
		echo "Deleting bridge br0"
		brctl delbr br0

		for IFACE in $IFACES ; do
			PREFIX=`echo $IFACE | cut -b1-3`
			case "$PREFIX" in
			  tap)
				echo "Deleting interface: $IFACE"
				/usr/lib/virtualbox/VBoxTunctl -d $IFACE &> /dev/null
				;;
			  eth)
				#brctl delif $IFACE
				echo "Configuring interface $IFACE with address $CURRENT_IP"
				ifconfig $IFACE $CURRENT_IP -promisc
				echo "Adding route to gateway $CURRENT_GW"
				route add default gw $CURRENT_GW
				;;
			esac
		done

		echo "Done!"
		;;
	*)
		echo "Usage: vbox {start [number of virtual interfaces] [user] | stop}"
		;;
esac