# Copyright 2004-2007 Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2

_config_vars="$_config_vars link suffix relay"

ip6to4_depend() {
	after interface
}

ip6to4_start() {
	case " ${MODULES} " in
		*" ifconfig "*)
			if [ "${IFACE}" != "sit0" ] ; then
				eerror "ip6to4 can only work on the sit0 interface using ifconfig"
				eerror "emerge sys-apps/iproute2 to use other interfaces"
				return 1
			fi
	esac

	local host= suffix= relay= addr= iface=${IFACE} new= localip=
	eval host=\$link_${IFVAR}
	if [ -z "${host}" ] ; then
		eerror "link_${IFVAR} not set"
		return 1
	fi

	eval suffix=\${suffix_${IFVAR}:-1}
	eval relay=\${relay_${IFVAR}:-192.88.99.1}

	IFACE=${host}
	addrs=$(_get_inet_addresses)
	IFACE=${iface}
	if [ -z "${addrs}" ] ; then
		eerror "${host} is not configured with an IPv4 address"
		return 1
	fi

	for addr in ${addrs} ; do
		# Strip the subnet
		local ip="${addr%/*}" subnet="${addr#*/}"
		# We don't work on private IPv4 addresses
		case "${ip}" in
			127.*) continue ;;
			10.*) continue ;;
			192.168.*) continue ;;
			172.*)
				local i=16
				while [ ${i} -lt 32 ] ; do
					case "${ip}" in
						172.${i}.*) break ;;
					esac
					i=$((${i} + 1))
				done
				[ ${i} -lt 32 ] && continue
				;;
		esac
	
		veinfo "IPv4 address on ${host}: ${ip}/${subnet}"
		local OIFS=$IFS SIFS=${IFS-y} ipa= ip6=
		IFS="${IFS}."
		for i in ${ip} ; do
			ipa="${ipa} ${i}"
		done
		if [ "${SIFS}" = "y" ] ; then
			IFS=$OIFS
		else
			unset IFS
		fi
		eval ip6="$(printf "2002:%02x%02x:%02x%02x::%s" ${ipa} ${suffix})"
		veinfo "Derived IPv6 address: ${ip6}"

		# Now apply our IPv6 address to our config
		new="${new}${new:+ }${ip6}/16"

		if [ -n "${localip}" ] ; then
			localip="any"
		else
			localip="${ip}"
		fi
	done

	if [ -z "${new}" ] ; then
		eerror "No global IPv4 addresses found on interface ${host}"
		return 1
	fi

	if [ "${IFACE}" != "sit0" ] ; then
		ebegin "Creating 6to4 tunnel on ${IFACE}"
		_tunnel add "${IFACE}" mode sit ttl 255 remote any local "${localip}"
		eend $? || return 1
		_up
	fi
	
	# Now apply our config
	eval config_${config_index}=\'"${new}"\'
	config_index=$((${config_index} - 1))

	# Add a route for us, ensuring we don't delete anything else
	eval $(_get_array "routes_${IFVAR}")
	eval routes_${IFVAR}="\"$@ '2003::/3 via ::${relay} metric 2147483647'\""
}
	
# vim: set ts=4 :
