#!/bin/bash
###############################################################################
#                                                                             #
# IPFire.org - A linux based firewall                                         #
# Copyright (C) 2012  IPFire Network Development Team                         #
#                                                                             #
# This program is free software: you can redistribute it and/or modify        #
# it under the terms of the GNU General Public License as published by        #
# the Free Software Foundation, either version 3 of the License, or           #
# (at your option) any later version.                                         #
#                                                                             #
# This program is distributed in the hope that it will be useful,             #
# but WITHOUT ANY WARRANTY; without even the implied warranty of              #
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the               #
# GNU General Public License for more details.                                #
#                                                                             #
# You should have received a copy of the GNU General Public License           #
# along with this program.  If not, see <http://www.gnu.org/licenses/>.       #
#                                                                             #
###############################################################################

NETWORK_DHCP_DUID_FILE="${NETWORK_CONFIG_DIR}/dhcp-duid"

dhclient_start() {
	local interface=${1}
	local proto=${2}

	assert isset interface
	assert device_exists ${interface}

	local service=$(dhclient_proto2service ${proto} ${interface})
	service_start ${service}
}

dhclient_stop() {
	local interface=${1}
	local proto=${2}

	local service=$(dhclient_proto2service ${proto} ${interface})
	service_stop ${service}
}

dhclient_status() {
	local interface=${1}
	local proto=${2}

	local service=$(dhclient_proto2service ${proto} ${interface})
	service_status ${service}
}

dhclient_proto2service() {
	local proto=${1}
	assert isset proto

	local interface=${2}
	assert isset interface

	local service

	case "${proto}" in
		ipv4)
			service="dhclient4@${interface}.service"
			;;
		ipv6)
			service="dhclient6@${interface}.service"
			;;
		*)
			return ${EXIT_ERROR}
			;;
	esac

	assert isset service

	echo "${service}"
	return ${EXIT_OK}
}

dhclient_write_config() {
	local interface="${1}"
	shift

	assert isset interface

	local hostname
	local vendor

	local config_file
	local leases_file

	while [ $# -gt 0 ]; do
		case "${1}" in
			--config-file=*)
				config_file="$(cli_get_val "${1}")"
				;;
			--hostname=*)
				hostname="$(cli_get_val "${1}")"
				;;
			--leases-file=*)
				leases_file="$(cli_get_val "${1}")"
				;;
			--vendor=*)
				vendor="$(cli_get_val "${1}")"
				;;
			*)
				log WARNING $"Unknown configuration option passed: ${1}."
				;;
		esac
		shift
	done

	assert isset config_file

	# Set default values
	if ! isset hostname; then
		hostname="$(config_hostname)"
	fi

	if ! isset vendor; then
		vendor="$(distro_get_pretty_name)"
	fi

	# Clear configuration file (if any).
	mkdir -p $(dirname ${config_file}) 2>/dev/null

	# Print the header.
	config_header "dhclient daemon configuration file for ${interface}" \
		> "${config_file}"

	# Global options.
	fappend "${config_file}" "send vendor-class-identifier \"${vendor}\";"
	fappend "${config_file}" # empty line

	# Interface options.
	(
		echo "interface \"${interface}\" {"

		if isset hostname; then
			echo "	send host-name \"${hostname}\";"
			print
		fi

		echo "}"
	) >> "${config_file}"

	# Update leases file
	if isset leases_file; then
		__dhclient_update_leases_file "${leases_file}" || return $?
	fi

	return ${EXIT_OK}
}

dhclient_get_duid() {
	# If the DUID already exists, we do not do anything at all.
	if [ -s "${NETWORK_DHCP_DUID_FILE}" ]; then
		print "$(<${NETWORK_DHCP_DUID_FILE})"
		return ${EXIT_OK}
	fi

	# If no DUID exists, we will need to create a new one
	local duid="$(dhclient_generate_duid)"
	log DEBUG "Created new DHCP DUID: ${duid}"

	# Save the new DUID to file and return it
	print "${duid}" > "${NETWORK_DHCP_DUID_FILE}"

	print "${duid}"
	return ${EXIT_OK}
}


dhclient_generate_duid() {
	# Find lowest MAC/link-local address
	local address="$(ports_lowest_address)"

	# Use a random MAC address if no physical address could
	# be found.
	if ! isset address; then
		log WARNING "Could not determine the lowest MAC/link-local address"
		address="$(mac_generate)"
	fi

	log DEBUG "Using '${address}' to generate the DHCP DUID"

	print "00030001${address//\:/}"
	return ${EXIT_OK}
}

__dhclient_update_leases_file() {
	local file="${1}"

	local duid="$(dhclient_get_duid)"

	if [ -e "${leases_file}" ]; then
		local old_duid="$(__dhclient_get_duid_from_leases_file "${leases_file}")"

		if [ "${duid}" = "${old_duid}" ]; then
			log DEBUG "DUID in leases file matches. Nothing to do"
			return ${EXIT_OK}
		fi
	fi

	# If the leases file does not exist, yet, or the
	# DUID in there is different, we will create/overwrite
	# the leases file with the correct DUID.

	(
		printf "default-duid \""

		local i=0
		while [ ${i} -lt ${#duid} ]; do
			printf "\\\\\\\\"
			printf "x${duid:${i}:2}"
			i=$(( ${i} + 2 ))
		done

		print "\";"
	) > "${leases_file}"

	return ${EXIT_OK}
}

__dhclient_get_duid_from_leases_file() {
	local file="${1}"

	# Do nothing if the leases file cannot be read
	[ -r "${file}" ] || return ${EXIT_OK}

	local line
	while read line; do
		if [[ ${line} =~ ^default-duid ]]; then
			line="${line/default-duid/}"
			line="${line//\\\\x/}"
			line="${line//;/}"

			line="$(strip "${line}")"
			unquote "${line}"
			return ${EXIT_OK}
		fi
	done < "${file}"

	return ${EXIT_ERROR}
}