FreedomBox/actions/dynamicdns

#!/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
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}"

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`
        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 URL |awk '{print $2}'`
    fi  
}

doGetOpt()
{
    while getopts ":s:d:u:p:I:" 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
            ;;
            \?)
                echo "Invalid option: -$OPTARG" >&2
                exit 1
            ;;
        esac
    done
}

doWriteCFG()
{
    #always write to the inactive config - needs to be enabled vi "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
    rm $STATUSFILE

    #find the interface (always the default gateway interface)
    DEFAULT=`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=5" >> $FILE
    echo "execute=$0 success" >> $FILE
    echo "wildcard" >> $FILE
    
    #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 | 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" >> $FILE
            #if this line is added to config file, ez-ipupdate will be launched on startup via init.d
            echo "daemon" >> $FILE
        fi
    fi
}

doGetWANIP()
{
    if [ $IPURL ];then
        OUTFILE=`mktemp`
        wget -4 -o /dev/null -O $OUTFILE $IPURL
        WANIP=`cat $OUTFILE`
        rm $OUTFILE
    else
        #no WAN IP found because of missing check URL
        WANIP=${NOIP}
    fi
    echo $WANIP > $IPFILE
}

cmd=$1
shift
case $cmd in
    configure)
        doGetOpt $@
        doWriteCFG
    ;;
    start)
        if [ "$(cat $HELPERCFG |grep ^NAT | awk '{print $2}')" = "no" ];then
            mv $CFG_disabled $CFG
            /etc/init.d/${TOOLNAME} start
        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
    [ -f $CFG_disabled ] && FILE=$CFG_disabled
    [ -f $CFG ] && FILE=$CFG
    RESULT=0
    #if we know our WAN IP, only update if IP changes
    if [ "$OLDIP" != "$WANIP" -a "${WANIP}" != ${NOIP} ];then
        ${UPDATE_TOOL} -c $FILE
        RESULT=$?
        [ $RESULT -eq 0 ] && $0 success
        cat /proc/uptime |awk '{print $1}' |cut -d . -f 1 > $LASTUPDATE
    fi
    #if we don't know our WAN IP do a blind update once a hour
    if [ "${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
            ${UPDATE_TOOL} -c $FILE
            RESULT=$?
            [ $RESULT -eq 0 ] && $0 success
            cat /proc/uptime |awk '{print $1}' |cut -d . -f 1> $LASTUPDATE        
        fi
    fi 
    if [ $RESULT -ne 0 ];then
        $0 failed
    fi
    ;;
    stop)
        rm $CRONJOB 2> /dev/null
        /etc/init.d/${TOOLNAME} stop
        mv $CFG $CFG_disabled
    ;;
    success)
        DATE=`date`
        echo "last update done ($DATE)" > $STATUSFILE
    ;;
    failed)
        DATE=`date`
        echo "last update failed ($DATE)" > $STATUSFILE
    ;;    
    get-last-success)
        if [ -f $STATUSFILE ];then
            cat $STATUSFILE
        else
            echo "no update recorded since last config change"
        fi
    ;;
    status)
        doReadCFG
        PROC=`pgrep ${TOOLNAME}`
        if [ -f $CRONJOB ];then
             echo enabled 
        elif [ ! -z $PROC ];then 
            echo enabled
        else
            echo disabled
        fi
        echo $server
        echo $host
        echo $user
        echo $pass
        echo $IPURL
    ;;
    get-timer)
        echo $UPDATEMINUTES
    ;;
    clean)
        rm ${CFGDIR}/*
    ;;
    *)
        echo "usage: status|configure <options>|start|stop|update|get-nat|clean|success|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 ""
        echo "update                  do a one time update"
        echo "clean                   delete configuration"
        echo "success                 store update success"
        echo "failed                  store update failure"
        echo "get-nat                 return the detected nat type"
    ;;
esac
exit 0