subnetBot

#!/bin/bash

errorChecks () {
	input="$1"
	count=0
	checkFail=false

	IFS="." read -a addr <<< "$input"
	for element in "${addr[@]}"
	do
		
		if [ "${#element[@]}" -gt 3 ]
		then
			checkFail=true
		elif [ "$element" -gt 255 ]
		then
			checkFail=true
		fi
		
		arr["$count"]="$element"
		let "count++"

	done

	if [ "$count" -eq 5 ]
	then
		checkFail=true
	elif [ "$count" -lt 4 ]
	then
		checkFail=true
	fi	

	stringArr=("${arr[@]}")
}

calcSubnet () {
	subnetID="$1"
	subnetMask=()
	countIndex=0
	binarySum=0

	fullOcto=$(( $subnetID / 8 ))
	
	rest=$(( $subnetID - (8 * $fullOcto) ))

	for (( i=0; i<$fullOcto; i++ ))
	do
		subnetMask[$i]=255
		let "countIndex++"
	done

	if [ "$countIndex" -lt 4 ]
	then
		for (( i=0; i<$rest; i++ ))
		do
			binary=$(( 2**(7 - $i) ))
			binarySum=$(( $binary + $binarySum ))

		done

		subnetMask[$countIndex]=$binarySum

		emptyOcto=$(( 4 - $countIndex ))

		if [ "$emptyOcto" -gt 0 ]
		then
			for (( i=0; i<($emptyOcto-1); i++ ))
			do
				countIndex=$(( $countIndex + $i + 1 ))
				subnetMask[$countIndex]=0
			done
		fi
	fi
	
}

calcCIDR () {
	subnet=("$@")
	CIDR=0

	for element in "${subnet[@]}"
	do
		checkSum=0				
		
		while true
		do
			if [ "$element" -eq 255  ]
			then
				CIDR=$(( $CIDR + 8 ))
				break
			fi			

			for (( i=7; i>=0; i-- ))
			do
				multiOP=$(( 2**$i ))
				checkSum=$(( $checkSum + $multiOP ))
	
				if [ "$element" -eq "$checkSum" ]
				then
					CIDR=$(( $CIDR + $i ))
					break 2
				fi
			done
			
			break
		done
	done
}

getPrivateIP () {

	randomNumber=$(( $RANDOM % 3 + 1 ))

	if [ "$randomNumber" -eq 1 ]
	then
		ipArr=(10 0 0 0)
		randomSubnet=$(shuf -i 8-30 -n1)
		randomOcto=3
	elif [ "$randomNumber" -eq 2 ]
	then
		ipArr=(172 16 0 0)
		randomIP=$(shuf -i 16-31 -n1)
		ipArr[1]="$randomIP"
		randomSubnet=$(shuf -i 12-30 -n1)
		randomOcto=2
	elif [ "$randomNumber" -eq 3 ]
	then
		ipArr=(192 168 0 0)
		randomSubnet=$(shuf -i 16-30 -n1)
		randomOcto=2
	fi

	for (( i=0; i<"$randomOcto"; i++ ))
	do
		index=$(( 3 - $i )) 
		randomIP=$(( $RANDOM % 255 + 0 ))
		ipArr[$index]="$randomIP"		
	done

	calcSubnet "$randomSubnet"	
	subnetArr=("${subnetMask[@]}")

	echo "Gegebene IPv4: 		${ipArr[@]}"
	echo "Gegebenes Subnet: 	${subnetArr[@]}"
}

getUniqueIPs () {
	count=0

	for ipElement in "${ipArr[@]}"
	do
		if [ "${subnetArr[$count]}" -eq 255 ]
		then
			netID["$count"]="$ipElement"
		elif [ "${subnetArr[$count]}" -eq 0 ]
		then
			netID["$count"]=0
		else
			magicNumber=$(( 256 - ${subnetArr[$count]} ))
			multiple=$(( $ipElement / $magicNumber ))
			netID["$count"]=$(( $magicNumber * $multiple ))
		fi	
	
		let "count++"
	done

	count=0

	for ipElement in "${netID[@]}"
	do
		if [ "${subnetArr[$count]}" -eq 255 ]
		then
			broadcastIP["$count"]="$ipElement"
		elif [ "${subnetArr[$count]}" -eq 0 ]
		then
			broadcastIP["$count"]=255
		else
			broadcastIP["$count"]=$(( $magicNumber * ($multiple + 1) - 1 ))
		fi	
	
		let "count++"
	done

	firstIP=("${netID[@]}")
	firstIP[3]=$(( firstIP[3] + 1 ))

	lastIP=("${broadcastIP[@]}")
	lastIP[3]=$(( lastIP[3] - 1 ))
}


checkAnswer () {
	input="$1"
	answer="$2"
	correct="false"


	if [ "$input" = "$answer" ]
	then
		echo -e "\e[1;32mPERFEKT!\e[0m"
		echo -e "\n"

		sleep 1

		correct="true"
	else
		echo -e "\033[43m\e[30m Leider nicht korrekt. \e[0m\033[40m"
		echo -e "Gib \e[1;36m'n'\e[0m ein, um es nochmal zu versuchen. Oder gib \e[1;36m'l'\e[0m, um die Lösung anzuzeigen."

		read -e input
      		echo -e "\n"

      		if [ ! "$input" == "n" ] && [ ! "$input" == "l" ]
      		then
            		correct="true"

      		elif [ "$input" == "l" ]
      		then
               		echo -e "\n"
        		echo -e "Die Antwort wäre gewesen: \033[42m\e[30m $answer \033[40m\e[0m"
	      		echo -e "\n"
              		echo "Drücke eine beliebige Taste, um fortzufahren."

               		read -e input

	       		correct="true"
		fi
	fi
}

correct="false"

while true 
do
	echo "(1) Selber Subnet rechnen (Standard) oder (2) den Bot eins ausrechnen lassen?"
	read input

	clear

	if [ "$input" = "2" ]
	then
		while true
		do
			echo "IPv4-Adresse eingeben: "

			read -e ipInput
	
			errorChecks "$ipInput"
	
			if [ "$checkFail" = "true" ]
			then
				echo -e "\e[1;31mUngültige Adresse.\e[0m"
			else
				break
			fi
		done
		
		ipArr=("${arr[@]}")	
	
		echo -e "\n"
	
		while true
		do
			echo "Subnetzmaske oder CIDR-Notation (inkl. /) eingeben: "
			read -e subnetInput
	
			if [[ ${subnetInput:0:1} == "/" ]]
			then
				cidr="${subnetInput:1:2}"
			
				if [ "$cidr" -gt 32 ]
				then
					echo -e "\e[1;31mFehlerhafte CIDR-Notation.\e[0m"
				else
					calcSubnet "$cidr"
					subnetArr=("${subnetMask[@]}")
					CIDRNotation="$subnetInput"
					break
				fi
			else
				errorChecks "$subnetInput"		
				
				if [ "$checkFail" = "true" ]
				then
					echo -e "\e[1;31mUngültige Adresse.\e[0m"
				else
					subnetArr=("${arr[@]}")
					calcCIDR "${subnetArr[@]}"
					CIDRNotation="/$CIDR"
					break
				fi
			fi
		done

		getUniqueIPs
	
		echo -e "\n"
		echo "IP-Adresse:	${ipArr[@]}"
		echo "Subnet Mask:	${subnetArr[@]}"
		echo "CIDR-Notation:	$CIDRNotation"
		echo "NetID:		${netID[@]}"
		echo "BroadcastIP:	${broadcastIP[@]}"
		echo "First Host-IP:	${firstIP[@]}"
		echo "Last Host-IP:	${lastIP[@]}"
		echo -e "\n"

		break
	else
		getPrivateIP
		getUniqueIPs
		
		echo -e "\n"
		
		while true
		do
			while [ "$correct" = "false" ]
			do
				while true			
				do
					echo "Gebe die NetID an: "
					read -e input

					errorChecks "$input"
	
					if [ "$checkFail" = "true" ]
					then
						echo -e "\e[1;31mUngültige Adresse.\e[0m"
					else
						break
					fi
				done
		
				input=("${arr[*]}")
				answer=("${netID[*]}")
	
				checkAnswer "$input" "$answer"
			done

			correct=false
			
			while [ "$correct" = "false" ]
			do
				while true			
				do
					echo "Gebe die Broadcast IP an: "
					read -e input

					errorChecks "$input"
	
					if [ "$checkFail" = "true" ]
					then
						echo -e "\e[1;31mUngültige Adresse.\e[0m"
					else
						break
					fi
				done
		
				input=("${arr[*]}")
				answer=("${broadcastIP[*]}")
	
				checkAnswer "$input" "$answer"
			done

			correct=false			
			
			while [ "$correct" = "false" ]
			do
				while true			
				do
					echo "Gebe die First Host IP an: "
					read -e input

					errorChecks "$input"
	
					if [ "$checkFail" = "true" ]
					then
						echo -e "\e[1;31mUngültige Adresse.\e[0m"
					else
						break
					fi
				done
		
				input=("${arr[*]}")
				answer=("${firstIP[*]}")
	
				checkAnswer "$input" "$answer"
			done

			correct=false
			
			while [ "$correct" = "false" ]
			do
				while true			
				do
					echo "Gebe die Last Host IP an: "
					read -e input

					errorChecks "$input"
	
					if [ "$checkFail" = "true" ]
					then
						echo -e "\e[1;31mUngültige Adresse.\e[0m"
					else
						break
					fi
				done
		
				input=("${arr[*]}")
				answer=("${lastIP[*]}")
	
				checkAnswer "$input" "$answer"
			done

			correct=false
			
			break 2
		done
	fi
done