#!/bin/bash
# zoneeditscript v0.7
# by sean@lolyco.com
#
# v0.7 quoted args to logger to stop it getting confused by GET_WAN_IP args
# v0.6 a more rigorous check on result of GET_WAN_IP
# v0.5 added ping -R method and 10 minute sleep for whatismyip.org
# v0.4 added date to error output
# v0,3 adds whatismyip.org
# v0.2 moves wrongly placed sleep ZEDRELAX
#
# Run from eg. rc.local:
# killall zoneeditscript; nohup /etc/zoneeditscript >> /var/log/zoneedit &
#
# Enter your Zoneedit username and password:
ZEDUSER=
ZEDPASS=
#################################################################################
# choose a WAN IP discovery method - uncomment one only
#################################################################################
# SNMP - change SNMP_IP to your SNMP-enabled router's LAN IP address
# This option HAS CAUSED CHEAP ROUTERS TO BECOME UNRESPONSIVE!
# SNMP_IP=192.168.1.1
# GET_WAN_IP="snmpwalk -v 1 -c public $SNMP_IP IP-MIB::ipAdEntAddr | grep -v $SNMP_IP | grep -v 127.0.0.1 | sed \"s/.* \([^ ]*\)$/\1/\""
# ZEDSLEEP=180
##################################################################################
# whatismyip.org - says once every ten minutes
# GET_WAN_IP="curl -s http://www.whatismyip.org"
# whatismyip.org says once every ten minutes!
# ZEDSLEEP=600
#################################################################################
# whatismyip.com - hit slowly!
# GET_WAN_IP="curl -s http://www.whatismyip.com/automation/n09230945.asp"
# ZEDSLEEP=180
#################################################################################
# ping return path - set PING_HOST to the address or name of a nearby (friendly) host
PING_HOST=
# set WAN_IP_LINE to the number of the line your WAN address appears on
WAN_IP_LINE=4
GET_WAN_IP="ping -nRc 1 $PING_HOST | sed -n ${WAN_IP_LINE}p | tr -d [:blank:]"
# Assuming pings can be fairly frequent:
ZEDSLEEP=60
#################################################################################
# zoneedit.com - you supply the code, I think they should change the page
# GET_WAN_IP=# no zoneedit option, it's even more ugly than the SNMP one
# ZEDSLEEP=180
################################################################################
# In case of problems leading to repeated erroneous zoneedit update queries,
# go to sleep for a long time after an update:
# 1000 seconds is jut over a quarter of an hour. 
# 
ZEDRELAX=1000
#
# Stop editing!
#
ZEDTHIS=$0
ZEDHOME=`dirname $0`
IPADDR=""

parse_hosts()
{
	grep -v ^# $ZEDHOME/zoneedit.hosts | tr -d [:blank:] | grep .... | \
	{
		while true
		do
			read host || break
			[ x$hosts == x ] && hosts=$host || hosts=$hosts,$host
		done
		echo $hosts
	}
}

update_zoneedit()
{
	ZEDHOSTS=`parse_hosts`;
	ZEDRESP=`curl -s --user $ZEDUSER:$ZEDPASS http://dynamic.zoneedit.com/auth/dynamic.html?host=$ZEDHOSTS`
	if echo $ZEDRESP | grep ERROR
	then
		logger -t $ZEDTHIS ERROR on IP address update
		logger -t $ZEDTHIS "$ZEDRESP"
	elif echo $ZEDRESP | grep SUCCESS
	then
		logger -t $ZEDTHIS "Updated IP to $IPADDR"
	else
		logger -t $ZEDTHIS "Unexpected response: $ZEDRESP"
	fi
	sleep $ZEDRELAX
}

echo `date` Zoneedit restarted
trap update_zoneedit SIGHUP
IPOLDADDR="notset"
while true
do
	IPADDR=`eval $GET_WAN_IP`
# check we got an IP address back, only 4 numbers, separated by 3 dots, no whitespace
	if [ x`echo $IPADDR | sed s/^[0-9][0-9]*\.[0-9][0-9]*\.[0-9][0-9]*\.[0-9][0-9]*$/IP/` == xIP ]
	then
		echo `date` $IPADDR
		[ x$IPADDR != x$IPOLDADDR ] && update_zoneedit
		IPOLDADDR=$IPADDR
	else
		logger -t $ZEDTHIS "No IP address in response from $GET_WAN_IP"
		logger -t $ZEDTHIS "IPADDR is $IPADDR"
		echo `date` No IP address: $GET_WAN_IP returns $IPADDR
	fi
	sleep $ZEDSLEEP
done