#!/bin/bash

#	DHCP commit/release/expiry status drives this process

###############     following 7 lines for testing  only    ###############
#	Kill the unbound-dhcp-leases-bridge process
pgrep -f unbound-dhcp-leases-bridge &&
	kill -s SIGTERM $(pgrep -d',' -f unbound-dhcp-leases-bridge)

#	chmod -v 744 /root/dhcpdconf/dhcpEvent_vN.sh
#	ln -vsf /root/dhcpdconf/dhcpEvent_vN.sh /root/dhcpdconf/dhcpEvent.sh
#-------------------------------------------------------------------------


dhcpCREstatus="${1:-}"
clientIP="${2:-}"
clientHostname="${3:-}"

unboundDHCPleases="/etc/unbound/dhcp-leases.conf"
unboundStaticHosts="/etc/unbound/hosts.conf"

#	time to live (seconds)
TTL="60"	#	time to live (seconds)

tagName="dhcpEv25"	#	to be "dhcpEvent"

###############     Functions     ###############

#	write A & PTR records to unbound
#
write-unbound () {
	local IPaddr
	local clientName
	local revIP
	local recA
	local recPTR

	IPaddr=$1
	clientName=$2

	#	create reverse IP for arpa name
	revIP=$( echo "${IPaddr}" | /usr/bin/awk -F. '{print $4"."$3"."$2"."$1}' )

	#	create "A" record and "PTR" record for unbound
	recA="${clientName}.${DOMAINNAME}. ${TTL} IN A ${IPaddr}"
	recPTR="${revIP}.in-addr.arpa. ${TTL} IN PTR ${clientName}.${DOMAINNAME}."

	#	send A & PTR records to unbound and dhcp-leases file
	echo -e "${recA}\n${recPTR}" | /usr/sbin/unbound-control local_datas
	echo "local-data: \"${recA}\"" >> "${unboundDHCPleases}"
	echo "local-data: \"${recPTR}\"" >> "${unboundDHCPleases}"

	msg_log "${dhcpCREstatus}: added A & PTR records to unbound"
}

#	delete A & PTR records from unbound, by IP address
#
delete_unbound () {
	local IPaddr
	local revIP
	local fqdn
	local deleteList

	local IPaddr=$1

	#	need IP address to get FQDN and arpa name
	revIP=$( echo "${IPaddr}" | /usr/bin/awk -F. '{print $4"."$3"."$2"."$1}' )
	fqdn=$( /bin/grep --word-regexp --ignore-case "${IPaddr}" <<< "${ucList}" | \
		/usr/bin/awk '{ print $1 }' )

	#	does a FQDN exist for this IP address?  If yes, then remove
	if [[ -n "${fqdn}" ]] ; then
		#	remove fqdn names from unbound AND dhcp-leases file

		#	look for multiple instances of fqdn (client hostname.domain)
		deleteList=$( /bin/grep --word-regexp --ignore-case "${fqdn}" <<< "${ucList}" | \
			/usr/bin/awk '{ print $1 }' )

		#	delete from unbound cache
		echo "${deleteList}" | /usr/sbin/unbound-control local_datas_remove

		#	delete from dhcp-leases.conf file
		/bin/sed --in-place "/\b${fqdn}/d" "${unboundDHCPleases}"
	else
		msg_log "${dhcpCREstatus}: Oops, no FQDN - exit"
		return 1
	fi
	msg_log "${dhcpCREstatus}: references to ${fqdn} removed from unbound"
}

#	send message to message log
msg_log () {
	if tty --silent ; then
		echo "${tagName}:" "$*"
	else
		/usr/bin/logger --tag "${tagName}" "$*"
	fi
}

###############     Main     ###############

#	check parameter count
if (( "$#" < 2 )) || (( $# > 3 )); then
    msg_log "Illegal number of parameters - exit"
	exit 1
fi

#	simple check for valid IP addr ( may be too simple! )
if ! /bin/grep --quiet --extended-regexp '[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}' <<< "${clientIP}" ; then
	msg_log "${clientIP} is an invalid IP address - exit"
	exit
fi

#	need DOMAINNAME value
eval "$(/usr/local/bin/readhash /var/ipfire/main/settings)"

#	remove invalid characters in client hostname
clientHostname=$( echo "${clientHostname}" | /bin/sed 's/[^A-Za-z0-9.-]//g' )

#	get existing records from unbound-control list_local_data
ucList=$( /usr/sbin/unbound-control list_local_data | /bin/grep -i "${DOMAINNAME}" | expand -t1 )

#	Does this Record A already exist?
UC_RecA=$( /bin/grep --ignore-case "^${clientHostname}\.${DOMAINNAME}.*${clientIP}$" <<< "${ucList}" )

#	find IP addr in unbound
UC_IP=$( /bin/grep --word-regexp --ignore-case "${clientIP}" <<< "${ucList}" )

#	find client name, at start of line, in unbound (looking for record A)
UC_FQDN=$( /bin/grep --word-regexp --ignore-case "^${clientHostname}\.${DOMAINNAME}" <<< "${ucList}" )

case "${dhcpCREstatus}" in
	commit)

		#	if client hostname is blank then exit
		if [[ -z "${clientHostname}" ]] ; then
			msg_log "${dhcpCREstatus}: received IP ${clientIP} but missing client hostname - exit"
			exit
		fi

		#	if client exists in static hosts then exit
		if /bin/grep --word-regexp --quiet --ignore-case -e "${clientIP}" -e "${clientHostname}" "${unboundStaticHosts}"
		then
			msg_log "${dhcpCREstatus}: ${clientHostname} or ${clientIP} found in static hosts - exit"
			exit
		fi
																						# (ip   fqdn)
		if [[ -n "${UC_RecA}" ]] ; then
		#	existing IP and existing FQDN												# ( 1   1 )
			msg_log "${dhcpCREstatus}: unbound hostname & IP already exist - exit"
			exit
		else

			if [[ -z "${UC_IP}" ]] ; then
				#	New IP address! - write info to unbound & dhcp-leases.conf			# ( 0   0/1 )
				write-unbound "${clientIP}" "${clientHostname}"
			else
				#	Existing IP address!
				if [[ -z "${UC_FQDN}" ]] ; then
				#	Existing IP and new FQDN
					#	hostname/fqdn changed - delete A & PTR records from unbound		# ( 1   0 )
					delete_unbound "${clientIP}"

					#	add new to unbound!
					write-unbound "${clientIP}" "${clientHostname}"
				fi
			fi
		fi
		;;

	release|expiry)
		#	NOTE: expiry & release are the same since I don't understand the difference    :-(

		if [[ -z "${clientIP}" ]] ; then
			msg_log "${dhcpCREstatus}: missing client IP address - exit"
			exit 1
		fi

		#	does IP addr appear in unbound?  if yes, delete lines
		if [[ -n "${UC_IP}" ]] ; then
			delete_unbound "${clientIP}"
		else
			msg_log "${dhcpCREstatus}: ${clientIP} not found in unbound - done"
		fi
		;;

	*)
		msg_log "CRE script: case = no status - exit"
		exit
		;;
esac

exit