#!/usr/bin/env bash

#####################################################
# This script require the following DNS SETUP!!!!
# SEE:
# https://git.giaever.org/joachimmg/dnssec-signer)
#
# USAGE: 
#
# 1. Make `opendkim-setter` executable:
# 	chmod +x /path/to/opendkim-setter
# 
# 2. Run:
# 	./path/to/opendkim-setter <domain.tld>
# 3. Or for every domain already signed by OpenDKIM
# 	./path/to/opendkim-setter
#
######################################################

SELF="$(basename ${0})"

######################################################
# 		  START OF CONFIG		     #
######################################################
# SET YOU SYSTEM SPECIFIC DATA (which systemctl e.g) #
SELF=$(basename $0)

DKIMUSER="opendkim"
DKIMGRP="${DKIMUSER}"
DKIMCONF="/etc/opendkim"
KEYTABLE="${DKIMCONF}/key.table"
SIGNTABLE="${DKIMCONF}/signing.table"
KEYDIR="${DKIMCONF}/keys"
ZONESDIR="/etc/bind/zones"
KEYGEN=/usr/bin/opendkim-genkey
SYSCTL=/bin/systemctl
JOURCTL=/bin/journalctl
LOGGER=/usr/bin/logger
LOGGERFLAGN="-t $(whoami) -p daemon.info"
LOGGERFLAGE="-t $(whoami) -p daemon.err"

RESIGNDNS=1
DNSTOOL=/usr/bin/dnssec-signer

######################################################
# 	   	    END OF CONFIG		     #
######################################################

function error_msg {
	FOR=${1}
	ERRMSG="${2}"
	echo -e "\e[31m[${SELF}:\e[1m${FOR}\e[21m]:\e[0m ${ERRMSG}"
	${LOGGER} ${LOGGERFLAGE} "[${SELF}:${FOR}]: ${ERRMSG}"
}

function note_msg {
	FOR=${1}
	NOTEMSG="${2}"
	echo -e "\e[32m[${SELF}:\e[1m${FOR}\e[21m]:\e[0m ${NOTEMSG}"
	${LOGGER} ${LOGGERFLAGN} "[${SELF}:${FOR}]: ${NOTEMSG}"
}

if [[ ${EUID} -ne 0 ]]; then
	error_msg "${USER}" "Must execute file as root."
	exit 1
fi

#function remove_signing_table {
#	grep -v "*@${1} " "${SIGNTABLE}" > "${TMPTBL}" && mv "${TMPTBL}" "${SIGNTABLE}"
#}

function update_signing_table {
	grep -q "^*@${1}" "${SIGNTABLE}"
	if [ $? -ne 0 ]; then
		note_msg "${1}" "Added to signing table"
		echo "*@${1} ${1}" >> "${SIGNTABLE}"
	fi
}

function update_key_table {
	grep -q "^${1}" "${KEYTABLE}"
	if [ $? -eq 0 ]; then
		note_msg "${1}" "Updated key in key table"
		sed -i 's,^'"${1}"'[^\n]\+,'"${1}"' '"${1}"':'"${2}"':'"${3}"',' "${KEYTABLE}"
	else
		note_msg "${1}" "Added key to key table"
		echo "${1} ${1}:${2}:${3}" >> "${KEYTABLE}"
	fi
}

function dkim {
	ENTRY="${1}"
	ENTRYDIR="${KEYDIR}/${ENTRY}"
	ENTRYZONE="${ZONESDIR}/${ENTRY}/db"
	DATE=$(date +%Y%m)
	PRIVATEKEY="${ENTRYDIR}/${DATE}.private"
	DOMAINKEY="${ENTRYDIR}/${DATE}.txt"
	note_msg "${ENTRY}" "DKIM Signing"

	if ! [ -w "${ENTRYZONE}" ]; then
		error_msg "${ENTRY}" "There is not zone file. Abort"
		return 1
	fi 

	if ! [ -d "${ENTRYDIR}" ]; then
		note_msg "${ENTRY}" "Creating directory for entry"
		mkdir -p "${ENTRYDIR}"
	fi
		
	cd "${ENTRYDIR}"

	${KEYGEN} -b 2048 -h rsa-sha256 -r -s "${DATE}" -d "${ENTRY}" -v

	if [ $? -ne 0 ]; then
		error_msg "${ENTRY}" "Error generating keys"
	fi

	KEYCONTENT=$(sed -e 's/h\=rsa-sha256/h\=sha256/' "${DOMAINKEY}" | tr '\n' '\r')
	ZONE=$(cat "${ENTRYZONE}" | tr '\n' '\r')

	grep -Eq "[0-9]{6}._dom" <<< "${ZONE}"
	if [ $? -eq 0 ]; then
		note_msg "${ENTRY}" "Altering DKIM-record in zone file"
		sed -e 's,[0-9]\{6\}._dom.*\-\+\sDKIM[^\r]\+\r\?\+,'"${KEYCONTENT}"',' <<< "${ZONE}" | tr '\r' '\n' > "${ENTRYZONE}"
		sed -i '${/^$/d;}' "${ENTRYZONE}"
	else
		note_msg "${ENTRY}" "Adding DKIM-record in zone file"
		echo -e "${ZONE}\r; DKIM for ${DOMAINKEY} start\r${KEYCONTENT}" | tr '\r' '\n' > "${ENTRYZONE}"
	fi

	update_signing_table "${ENTRY}"
	update_key_table "${ENTRY}" "${DATE}" "${PRIVATEKEY}"
	note_msg "${ENTRY}" "Signing successful"
}

# Collect arguments (zones)
ENTRIES="${*}"
IFS=' ', read -r -a ENTRIES <<< "${ENTRIES}"

if [ ${#ENTRIES[@]} -ne 0 ]; then
	note_msg "date" "$(date)"
	note_msg "${#ENTRIES[@]}" "Start signing"
	CWDIR=$(pwd)
	for ENTRY in "${ENTRIES[@]}"; do
		dkim "${ENTRY}"
	done
	cd "${CWDIR}"
	chown -R "${DKIMUSER}:${DKIMGROUP}" "${DKIMCONF}"
	chmod -R go-rw "${DKIMCONF}"
	if [ "${RESIGNDNS}" -eq 1 ]; then
		note_msg "$(basename ${SYSCTL})" "Restarting opendkim.service"
		${SYSCTL} restart "opendkim.service"
		if [ $? -ne 0 ]; then
			${JOURCTL} -l 10 --unit "opendkim.service" | xargs -0
		fi
		${DNSTOOL} "${ENTRIES[@]}"
	fi
else
	for ENTRY in $(cat "${SIGNTABLE}"); do
		if ! [[ "${ENTRY}" == "*"* ]]; then
			ENTRIES[${#ENTRIES[@]}]="${ENTRY}"
		fi
	done
	${SELF} "${ENTRIES[@]}"
fi