#!/bin/sh

if [ "$ACTION" = ifup ]; then
	. /etc/functions.sh

	include /lib/network
	scan_interfaces

	update_tunnel() {
		local cfg="$1"

		local proto
		config_get proto "$cfg" proto
		[ "$proto" = 6in4 ] || return 0

		local wandev
		config_get wandev "$cfg" wan_device "$(find_6in4_wanif)"
		[ "$wandev" = "$DEVICE" ] || return 0

		local wanip=$(find_6in4_wanip "$wandev")

		[ -n "$wanip" ] && {
			lsmod | grep -q ^sit || {
				logger -t 6in4-update "Tunneling driver not loaded yet, deferring action"
				exit 0
			}

			local tunnelid
			config_get tunnelid "$cfg" tunnelid

			local username
			config_get username "$cfg" username

			local password
			config_get password "$cfg" password

			uci_set_state network "$cfg" ipaddr "$wanip"

			[ -n "$tunnelid" ] && [ -n "$username" ] && [ -n "$password" ] && {
				[ "${#password}" == 32 -a -z "${password//[a-fA-F0-9]/}" ] || {
					password="$(echo -n "$password" | md5sum)"; password="${password%% *}"
				}

				(
					local url="http://ipv4.tunnelbroker.net/ipv4_end.php?ip=AUTO&apikey=$username&pass=$password&tid=$tunnelid"
					local try=0
					local max=3

					while [ $((++try)) -le $max ]; do
						wget -qO/dev/null "$url" 2>/dev/null && {
							logger -t 6in4-update "Updated tunnel #$tunnelid endpoint to $wanip"
							ifup "$cfg"
							break
						} || {
							logger -t 6in4-update "Try $try/$max failed, retrying"
							sleep 1
						}
					done
				)&
			} || {
				logger -t 6in4-update "Re-establishing tunnel due to change on $INTERFACE ($DEVICE)"
				ifup "$cfg" &
			}
		}
	}

	config_foreach update_tunnel interface
fi
