#!/bin/sh

# Set this if you don't want the script to figure out your IP (MUST BE EXTERNAL)
#IPV4ADDR=207.40.203.241

# Remote box to connect to. For AnyCast (192.88.99.1) use "any"
REMOTE=any
#REMOTE=64.71.128.82

# default 6to4 relay to use
#RELAY=192.88.99.1

# tunnel name to use default is tun6to4
#TUN_IF=tun6to4

# local network connection interface if not set will figure it out
#LOCAL_IF=eth1


case "$1" in
    start)
	if [ -z "${IPV4ADDR}" ]; then
		if [ -z "${LOCAL_IF}" ]; then
			LOCAL_IF=$(ip -o route show | grep '^default ' \
				| sed -e 's/^default.*dev \([^ ]*\).*/\1/')
		fi
		IPV4ADDR=$(ip -o addr show eth1 | grep ' inet ' \
			| grep -v ' secondary ' | head -n 1 | \
			sed -e 's/.*inet \([^ ]*\) .*/\1/' -e 's/\/.*//')
		if [ -z "${IPV4ADDR}" ]; then
			echo "Can't determine IP address assigned to ${LOCAL_IF}"
			exit 1
		fi
	fi
	
	if [ -z "${TUN_IF}" ]; then
		TUN_IF=tun6to4
	fi
	if [ -z "${RELAY}" ]; then
		RELAY=192.88.99.1
	fi
	if [ -z "${REMOTE}" ]; then
		REMOTE=any
	fi
	if [ -z "${IPV6ADDR}" ]; then
		IPV6ADDR=$(printf "2002:%02x%02x:%02x%02x::1\n" `echo $IPV4ADDR | tr . ' '`)
	fi

	echo "Your IPv4 address is: ${IPV4ADDR}"
	echo "Based on this address your IPv6 address for 6to4 tunneling is: ${IPV6ADDR}"
	echo "This will be relayed via: ${RELAY}"
	echo "Creating IPv6 tunnel"
	/sbin/ip tunnel add ${TUN_IF} mode sit ttl 255 remote ${REMOTE} local ${IPV4ADDR}
	echo "Bringing tunnel up"
	/sbin/ip link set dev ${TUN_IF} mtu 1472 up
	echo "Setting tunnel's IP address"
	/sbin/ip -6 addr add ${IPV6ADDR}/16 dev ${TUN_IF}
	
	#/sbin/ip -6 route add ::/0 dev ${TUN_IF} <- do we need this?
	#### This is for people not using 6bone but using the default AnyCast available to them
	/sbin/ip -6 route add ::/96 dev ${TUN_IF} metric 1
	/sbin/ip -6 route add 2000::/3 via ::${RELAY} dev ${TUN_IF} metric 1
	;;
    stop)
	if [ -z "${TUN_IF}" ]; then
		TUN_IF=tun6to4
	fi

	echo "Flushing routes"
	/sbin/ip -6 route flush dev ${TUN_IF}
	echo "Bringing tunnel down"
	/sbin/ip link set dev ${TUN_IF} down
	echo "Deleting tunnel"
	/sbin/ip tunnel del ${TUN_IF}
	;;
    *)
	echo "Usage: $0 {start|stop}"
	exit 1
	;;
esac

exit 0