#!/bin/bash
##
 # SDDNS update script
 #
 # @copyright	2013 Steffen Vogel
 # @license	http://www.gnu.org/licenses/gpl.txt GNU Public License
 # @author	Steffen Vogel <post@steffenvogel.de>
 # @link	http://www.steffenvogel.de
 ##
##
 # This file is part of sddns
 #
 # sddns is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation, either version 3 of the License, or
 # any later version.
 #
 # sddns is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with sddns. If not, see <http://www.gnu.org/licenses/>.
 ##

################################################################################
# Requirements
#
# This script requires bash, curl, dig
#
################################################################################
# Settings

# Password
PW=Ohsongei6

# Hostname
HOST=sea

# Zone
ZONE=0l.de

# Interface
IF=eth0

# Get ipv6 ip
#IPV6=$(ip -6 -o addr show dev eth0 dynamic scope global | sed -r 's/\s+/\t/g' | cut -f4 | cut -f1 -d/)

################################################################################
# Expert settings

# Time to live value in seconds for the record
TTL=120

# Type (A for IPv4, AAAA for IPv6)
TYPE=AAAA

################################################################################
# Do not touch anything under this!

RDATA=$(dig $TYPE $HOST.$ZONE @0l.de +short)

#       2: eth0 inet6 2a02:908:f318:7201:52e5:49ff:feeb:740c/64 scope global dynamic valid_lft 7200sec preferred_lft 3600sec
REGEX='^[0-9]+: +([^ ]+) +(inet6?) +([^/]+)/([0-9]+) +scope +global +dynamic +valid_lft +([0-9]+)sec +preferred_lft +([0-9]+)sec'

ip -o monitor address | while read ACTION; do
	if [[ ${ACTION} =~ ${REGEX} ]]; then
		if [ "${RDATA}" != "${BASH_REMATCH[3]}" ]; then
			WAIT=1
			RDATA=${BASH_REMATCH[3]}
			URL="http://d.0l.de/update.txt?host=$HOST&zone=$ZONE&ttl=$TTL&class=IN&type=$TYPE&rdata=$RDATA&pw=$PW"

			echo "Updating record: $URL"
			while [ $WAIT -lt 60 ] && ! curl "$URL" 2>/dev/null | sed 's/^/  /'; do
				sleep $WAIT; # wait until interface is ready
				WAIT=$(($WAIT*2))
			done
		else
			echo "Address hasn't changed: ${RDATA}"
		fi
	fi
done