#!/bin/bash
#Todo: IPv6
#Todo: Other service types than gnudip (generic update URL)
#Todo: GET WAN IP from Router via UPnP if supported

PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin

#static values
WGET=$(which wget)
WGETOPTIONS="-4 -o /dev/null -t 3 -T 3"
EMPTYSTRING="none"
NOIP="0.0.0.0"
#how often do we poll for IP changes if we are behind a NAT?
UPDATEMINUTES=5
#if we do not have a IP check URL, how often should we do a "blind" update
UPDATEMINUTESUNKNOWN=3600
TOOLNAME=ez-ipupdate
UPDATE_TOOL=$(which ${TOOLNAME})

#Dirs and filenames
CFGDIR="/etc/${TOOLNAME}/"
CFG="${CFGDIR}${TOOLNAME}.conf"
CFG_disabled="${CFGDIR}${TOOLNAME}.inactive"
IPFILE="${CFGDIR}${TOOLNAME}.currentIP"
STATUSFILE="${CFGDIR}${TOOLNAME}.status"
LASTUPDATE="${CFGDIR}/last-update"
HELPERCFG="${CFGDIR}${TOOLNAME}-plinth.cfg"
CRONJOB="/etc/cron.d/${TOOLNAME}"
PIDFILE="/var/run/ez-ipupdate.pid"

doGetOpt()
{
	basicauth=0
	ignoreCertError=0
	
    while getopts ":s:d:u:p:I:U:c:b:" opt; do
        case $opt in
            s)
                server=$OPTARG
            ;;
            d)
                host=$OPTARG
            ;;
            u)
                user=$OPTARG
            ;;
            p)
                pass=$OPTARG
            ;;
            I)
                if [ "$OPTARG" != "$EMPTYSTRING" ];then
                    ipurl=$OPTARG
                else
                    ipurl=""
                fi
            ;;
            U)
                if [ "$OPTARG" != "$EMPTYSTRING" ];then
                    updateurl=$OPTARG
                else
                    updateurl=""
                fi
            ;;
            b)
                basicauth=$OPTARG
            ;;
            c)
                ignoreCertError=$OPTARG
            ;;            
            \?)
                echo "Invalid option: -$OPTARG" >&2
                exit 1
            ;;
        esac
    done
}

doWriteCFG()
{
    mkdir $CFGDIR 2> /dev/null
    #always write to the inactive config - needs to be enabled via "start" command later
    file=$CFG_disabled

    #reset the last update time
    echo 0 > $LASTUPDATE

    #reset the last updated IP
    echo "0.0.0.0" > $IPFILE

    #reset last update (if there is one)
    rm $STATUSFILE 2> /dev/null

    #find the interface (always the default gateway interface)
    default_interface=`ip route |grep default |awk '{print $5}'`

    #store the given options in ez-ipupdate compatible config file
    echo "host=$host" > $file
    echo "server=$server" >> $file
    echo "user=${user}:${pass}" >> $file
    echo "service-type=gnudip" >> $file
    echo "retrys=3" >> $file
    echo "wildcard" >> $file
    
    #store UPDATE URL params
    echo "POSTURL $updateurl" > $HELPERCFG
    echo "POSTAUTH $basicauth" >> $HELPERCFG
    echo "POSTSSLIGNORE $ignoreCertError" >> $HELPERCFG
    
    #check if we are behind a NAT Router
    echo "IPURL $ipurl" >> $HELPERCFG
    if [ -z $ipurl ];then
        echo "NAT unknown" >> $HELPERCFG
    else 
        doGetWANIP
        ISGLOBAL=`ip addr ls $default_interface | grep $wanip`
        if [ -z $ISGLOBAL ];then
            #we are behind NAT
            echo "NAT yes" >> $HELPERCFG
        else
            #we are directly connected
            echo "NAT no" >> $HELPERCFG
            #if this file is added ez-ipupdate will take ip form this interface
            echo "interface=$default_interface" >> $file
            #if this line is added to config file, ez-ipupdate will be launched on startup via init.d
            echo "daemon" >> $file
            echo "execute=$0 success" >> $file
        fi
    fi
}

doReadCFG()
{ 
    host=""
    server=""
    user=""
    pass=""
    ipurl=""
    file=""
    [ -f $CFG_disabled ] && file=$CFG_disabled
    [ -f $CFG ] && file=$CFG

    if [ ! -z $file ];then
        host=`cat $file 2> /dev/null |grep host |cut -d = -f 2`
        server=`cat $file 2> /dev/null |grep server |cut -d = -f 2 |grep -v ^\'\'`
        user=`cat $file 2> /dev/null |grep user |cut -d = -f 2 |cut -d : -f 1 `
        pass=`cat $file 2> /dev/null |grep user |cut -d = -f 2 |cut -d : -f 2`
    fi

    if [ ! -z $HELPERCFG ];then
        ipurl=`cat $HELPERCFG 2> /dev/null |grep ^IPURL |awk '{print $2}' |grep -v ^\'\'`
        updateurl=`cat $HELPERCFG 2> /dev/null |grep POSTURL |awk '{print $2}' |grep -v ^\'\'`
        basicauth=`cat $HELPERCFG 2> /dev/null |grep POSTAUTH |awk '{print $2}' |grep -v ^\'\'`
        ignoreCertError=`cat $HELPERCFG 2> /dev/null |grep POSTSSLIGNORE |awk '{print $2}' |grep -v ^\'\'`
    fi  
}

doStatus()
{
	PROC=`pgrep ${TOOLNAME}`
	if [ -f $CRONJOB ];then
	     echo enabled 
	elif [ ! -z $PROC ];then 
	    echo enabled
	else
	    echo disabled
	fi
		if [ ! -z $server ];then
		echo $server
		else
			echo disabled
		fi
	if [ ! -z $host  ];then 
		echo $host
		else
			echo disabled
		fi
		if [ ! -z $user ];then
		echo $user
		else
			echo disabled
		fi
	if [ ! -z $pass  ];then 
		echo $pass
		else
			echo disabled
		fi        
		if [ ! -z $ipurl ];then
		echo $ipurl
		else
			echo disabled
		fi
	if [ ! -z $updateurl  ];then 
		echo $updateurl
		else
			echo disabled
		fi  
	if [ ! -z $basicauth ];then
		echo $basicauth
	else
			echo disabled
	fi		
	if [ ! -z $ignoreCertError ];then
		echo $ignoreCertError 
	else
		echo disabled
	fi	
}

doGetWANIP()
{
    if [ ! -z $ipurl ];then
        outfile=`mktemp`
        $WGET $WGETOPTIONS -O $outfile $ipurl
        wanip=`cat $outfile`
        rm $outfile
        [ -z $wanip ] && wanip=${NOIP}
    else
        #no WAN IP found because of missing check URL
        wanip=${NOIP}
    fi
}

doUpdate()
{
	if [ ! -z $server ];then 
		start-stop-daemon -S -x ${UPDATE_TOOL} -m -p ${PIDFILE} -- -c $file	
	fi
	
	if [ ! -z $updateurl ];then
		echo "todo"	
	fi
}

cmd=$1
shift
case $cmd in
    configure)
        doGetOpt $@
        doWriteCFG
    ;;
    start)
        if [ "$(cat $HELPERCFG |grep ^NAT | awk '{print $2}')" = "no" ];then
        	if [ -f $CFG -a ! -z $(cat $file 2> /dev/null |grep server |cut -d = -f 2 |grep -v ^\'\')];then
            	mv $CFG_disabled $CFG
            	/etc/init.d/${TOOLNAME} start        		
			fi
			if [ ! -z $(cat $HELPERCFG |grep ^POSTURL | awk '{print $2}') ];then
				echo "*/${UPDATEMINUTES} * * * * root $0 update" > $CRONJOB
            	$0 update
			fi
        else
            echo "*/${UPDATEMINUTES} * * * * root $0 update" > $CRONJOB
            $0 update
        fi
    ;;
    get-nat)
        NAT=`cat $HELPERCFG 2> /dev/null |grep ^NAT | awk '{print $2}'`
        [ -z $NAT ] && NAT="unknown"
        echo $NAT
    ;;
    update)
        doReadCFG
        oldip=`cat $IPFILE`
        doGetWANIP
        echo $wanip > $IPFILE
        cfgfile="/tmp/none"
        [ -f $CFG_disabled ] && cfgfile=$CFG_disabled
        [ -f $CFG ] && cfgfile=$CFG
        cat $file |grep -v execute > ${cfgfile}.tmp
        mv ${cfgfile}.tmp ${cfgfile}
        echo "execute=$0 success ${wanip}" >> $cfgfile
        #if we know our WAN IP, only update if IP changes
        if [ "${oldip}" != "${wanip}" -a "${wanip}" != ${NOIP} ];then
            doUpdate
        fi
        #if we don't know our WAN IP do a blind update once a hour
        if [ "${wanip}" = ${NOIP} ];then
            uptime=`cat /proc/uptime |cut -d . -f 1`
            LAST=0
            [ -f ${LASTUPDATE} ] && LAST=`cat $LASTUPDATE`
            diff=`expr $uptime - $LAST`
            if [ $diff -gt $UPDATEMINUTESUNKNOWN ];then
                doUpdate
            fi
        fi
    ;;
    stop)
        rm $CRONJOB 2> /dev/null
        /etc/init.d/${TOOLNAME} stop
        kill $(cat ${PIDFILE}) 2> /dev/null
        mv $CFG $CFG_disabled
    ;;
    success)
        date=`date`
        echo "last update done ($date)" > $STATUSFILE
        cat /proc/uptime |awk '{print $1}' |cut -d . -f 1 > $LASTUPDATE
        #if called from cronjob, the current IP is given as parameter
        if [ $# -eq 1 ];then
          echo $1 > $IPFILE
        else
          #if called from ez-ipupdate daemon, no WAN IP is given as parameter
          doGetWANIP
          echo $wanip > $IPFILE
        fi
    ;;
    failed)
        date=`date`
        echo "last update failed ($date)" > $STATUSFILE
    ;;    
    get-last-success)
        if [ -f $STATUSFILE ];then
            cat $STATUSFILE
        else
            echo "no successful update recorded since last config change"
        fi
    ;;
    status)
        doReadCFG
		doStatus			
    ;;
    get-timer)
        echo $UPDATEMINUTES
    ;;
    clean)
        rm ${CFGDIR}/*
        rm $CRONJOB
    ;;
    *)
        echo "usage: status|configure <options>|start|stop|update|get-nat|clean|success [updated IP]|failed"
        echo ""
        echo "options are:"
        echo "-s <server>             Gnudip Server address"
        echo "-d <domain>             Domain to be updated"
        echo "-u <user>               Account username"
        echo "-p <password>           Account Password"
        echo "-I <IP check URL>       A URL which returns the IP of the client who is requesting"
        echo "-U <update URL>         The update URL (a HTTP GET on this URL will be done)"
        echo "-c <1|0>                disable SSL check on Update URL"
        echo "-b <1|0>                use HTTP basic auth on Update URL"
        echo ""
        echo "update                  do a one time update"
        echo "clean                   delete configuration"
        echo "success                 store update success and optional the updated IP"
        echo "failed                  store update failure"
        echo "get-nat                 return the detected nat type"
    ;;
esac
exit 0