#!/bin/sh
if [ "$*" == "" ]
	then
	echo "Reini´s Netcalc Ver1.0"
	echo `basename $0`" IPAdresse/Switch"
	echo "oder"
	echo `basename $0`" IPAdresse Anzahl"
	echo "oder"
	echo `basename $0`" -m IPAdresse NetMask"
	echo ""
	echo "Example1.:"
	echo `basename $0`" 192.168.10.20/30"
	echo "Example2.:"
	echo `basename $0`" 192.168.10.20 4"
	echo "Example3.:"
	echo `basename $0`" -m 192.168.10.20 255.255.255.252"
	exit
fi
nmask=`echo ""`
input=`echo $*`
isscha=`echo $input|grep "/"`
zaehl=1
zaehl2=1
zaehl3=1
zaehl4=1
wert2=2
wert22=2
wert23=2
wert24=2
if [ "$1" == "-m" ]
	then
	f1=`echo $3|cut -f1 -d"."`
	f2=`echo $3|cut -f2 -d"."`
	f3=`echo $3|cut -f3 -d"."`
	f4=`echo $3|cut -f4 -d"."`
	if [ "$f1" != "255" ]
		then
		let anz=255-f1
		let anza=255*255*255*anz
		$0 $2 $anza
		exit
	fi
        if [ "$f2" != "255" ]
                then
                let anz=255-f2
                let anza=255*255*anz
                $0 $2 $anza
                exit
        fi
        if [ "$f3" != "255" ]
                then
                let anz=255-f3
                let anza=255*anz
                $0 $2 $anza
                exit
        fi
        if [ "$f4" != "255" ]
                then
                let anz=255-f4
                let anza=1*anz
                $0 $2 $anza
                exit
        fi
fi
if [ "$isscha" == "" ]
	then
	anza=`echo $input|cut -f2 -d" "`
	ip=`echo $input|cut -f1 -d" "`
	let a=anza-1
	l=`echo -e "obase=2;$a" | bc|wc -c`
	let ra=l-1
	let re=32-ra
	$0 $ip"/"$re
	echo "Mask = $ip"/"$re"
	exit
fi
if [ "$isscha" != "" ]
	then
	schalter=`echo $input|cut -f2 -d"/"`
	ipa=`echo $input|cut -f1 -d"/"`
fi
pos1=`echo $ipa|cut -f1 -d"."`
pos2=`echo $ipa|cut -f2 -d"."`
pos3=`echo $ipa|cut -f3 -d"."`
pos4=`echo $ipa|cut -f4 -d"."`
if [ "$schalter" -gt "32" ]
	then
	echo Zu hoher Wert
	exit
fi
if [ "$schalter" != "" ]
	then
	let pos=schalter/8
	if [ "$pos" -eq "0" ]
		then
                let wert4=8-schalter
                if [ "$wert4" -eq "0" ]
                        then
                        wert24=0
                fi
                while :
                        do
                        if [ "$wert4" -le "$zaehl4" ]
                                then
                                break
                        fi
                        let zaehl4=zaehl4+1
                        let wert24=wert24*2
                done
                reip4=`echo $ipa|cut -f1 -d"."`
                if [ "$wert24" -gt "1" ]
                        then
                        let wert34=wert24-1
                else
                        wert34=$wert24
                fi
                let reipa4=reip4+wert34
                if [ "$reipa4" -gt "255" ]
                        then
                        reip4=0
                        reipa4=255
                fi
                pos1=`echo $reip4"-"$reipa4`
		pos2=0-255
		pos3=0-255
		pos4=0-255
		let anzahl=$wert24*256*256*256
                if [ "$nmask" == "" ]
                        then
                        let mask=256-wert24
                        nmask=`echo "$mask".0.0.0`
                fi
        fi
	if [ "$pos" -eq "1" ]
		then
                let wert3=16-schalter
                if [ "$wert3" -eq "0" ]
                        then
                        wert23=0
                fi
                while :
                        do
                        if [ "$wert3" -le "$zaehl3" ]
                                then
                                break
                        fi
                        let zaehl3=zaehl3+1
                        let wert23=wert23*2
                done
                reip3=`echo $ipa|cut -f2 -d"."`
                if [ "$wert23" -gt "1" ]
                        then
                        let wert33=wert23-1
                else
                        wert33=$wert23
                fi
                let reipa3=reip3+wert33
                if [ "$reipa3" -gt "255" ]
                        then
                        reip3=0
                        reipa3=255
                fi
                pos2=`echo $reip3"-"$reipa3`
		pos3=0-255
		pos4=0-255
		let anzahl=$wert23*256*256
                if [ "$nmask" == "" ]
                        then
                        let mask=256-wert23
                        nmask=`echo 255."$mask".0.0`
                fi
        fi
	if [ "$pos" -eq "2" ]
		then
		let wert2=24-schalter
		if [ "$wert2" -eq "0" ]
                        then
                        wert22=0
                fi
                while :
                        do
                        if [ "$wert2" -le "$zaehl2" ]
                                then
                                break
                        fi
                        let zaehl2=zaehl2+1
                        let wert22=wert22*2
                done
                reip2=`echo $ipa|cut -f3 -d"."`
                if [ "$wert22" -gt "1" ]
                        then
                        let wert32=wert22-1
                else
                        wert32=$wert22
                fi
                let reipa2=reip2+wert32
                if [ "$reipa2" -gt "255" ]
                        then
                        reip2=0
                        reipa2=255
                fi
		pos3=`echo $reip2"-"$reipa2`
		pos4=0-255
		let anzahl=$wert22*256
		if [ "$nmask" == "" ]
                        then
			let mask=256-wert22
			nmask=`echo 255.255."$mask".0`
		fi
	fi
	if [ "$pos" -ge "3" ]
		then
		let wert=32-schalter
		if [ "$wert" -eq "0" ]
			then
			wert2=0
		fi
		while :
			do
			if [ "$wert" -le "$zaehl" ]
				then
				break
			fi
			let zaehl=zaehl+1
			let wert2=wert2*2
		done
		reip=`echo $ipa|cut -f4 -d"."`
		if [ "$wert2" -gt "1" ]
			then
			let wert3=wert2-1
		else
			wert3=$wert2
		fi
		let reipa=reip+wert3
		if [ "$reipa" -gt "255" ]
			then
			reip=0
			reipa=255
		fi
		pos4=`echo $reip"-"$reipa`
		anzahl=$wert2
		if [ "$nmask" == "" ]
			then
			if [ "$wert2" == "0" ]
				then
				wert2=1
			fi
			let mask=256-wert2
			nmask=`echo 255.255.255.$mask`
		fi
	fi
	echo "Reini´s Netcalc Ver1.0"
	echo "Bereich = "$pos1"."$pos2"."$pos3"."$pos4
	echo "Anzahl der Adressen = "$anzahl
	echo "Netmask = "$nmask
fi