#!/bin/sh /etc/rc.common

START=19
USE_PROCD=1
PROG=/usr/sbin/dhcpd

lease_file=/tmp/dhcpd.leases
config_file=/tmp/run/dhcpd.conf

time2seconds() {
	local timestring=$1
	local multiplier number suffix

	suffix="${timestring//[0-9 ]}"
	number="${timestring%%$suffix}"
	[ "$number$suffix" != "$timestring" ] && return 1
	case "$suffix" in
		"" | s)
			multiplier=1
			;;
		m)
			multiplier=60
			;;
		h)
			multiplier=3600
			;;
		d)
			multiplier=86400
			;;
		w)
			multiplier=604800
			;;
		*)
			return 1
			;;
	esac
	echo $(( number * multiplier ))
}

# duplicated from dnsmasq init script
hex_to_hostid() {
	local var="$1"
	local hex="${2#0x}" # strip optional "0x" prefix

	if [ -n "${hex//[0-9a-fA-F]/}" ]; then
		# is invalid hex literal
		return 1
	fi

	# convert into host id
	export "$var=$(
		printf "%0x:%0x" \
		$(((0x$hex >> 16) % 65536)) \
		$(( 0x$hex        % 65536))
		)"

	return 0
}

static_host_add() {
	local cfg="$1"
	local broadcast hostid macn macs mac name ip leasetime

	config_get macs "$cfg" "mac"
	[ -n "$macs" ] || return 0
	config_get name "$cfg" "name"
	[ -n "$name" ] || return 0
	config_get ip "$cfg" "ip"
	[ -n "$ip" ] || return 0

	config_get_bool broadcast "$cfg" "broadcast" 0
	config_get dns "$cfg" "dns"
	config_get gateway "$cfg" "gateway"
	config_get leasetime "$cfg" "leasetime"
	if [ -n "$leasetime" ] ; then
		leasetime="$(time2seconds "$leasetime")"
		[ "$?" -ne 0 ] && return 1
	fi

	config_get hostid "$cfg" "hostid"
	if [ -n "$hostid" ] ; then
		hex_to_hostid hostid "$hostid" || return 1
	fi

	macn=0
	for mac in $macs; do
		macn=$(( macn + 1 ))
	done

	for mac in $macs; do
		local secname="$name"
		if [ $macn -gt 1 ] ; then
			secname="${name}-${mac//:}"
		fi
		echo "host $secname {"
		echo " hardware ethernet $mac;"
		echo " fixed-address $ip;"
		echo " option host-name \"$name\";"
		if [ "$broadcast" -eq 1 ] ; then
			echo " always-broadcast true;"
		fi
		if [ -n "$leasetime" ] ; then
			echo " default-lease-time $leasetime;"
			echo " max-lease-time $leasetime;"
		fi
		if [ -n "$hostid" ] ; then
			echo " option dhcp-client-identifier $hostid;"
		fi
		if [ -n "$dns" ] ; then
			echo " option domain-name-servers $dns;"
		fi
		if [ -n "$gateway" ] ; then
			echo " option routers $gateway;"
		fi
		config_list_foreach "$cfg" "dhcp_option" append_dhcp_options
		echo "}"
	done
}

static_hosts() {
	config_foreach static_host_add host "$@"
}

typeof() {
	echo "$1" | awk '
/^\d+\.\d+\.\d+\.\d+$/		{ print "ip\n"; next; }
/^(true|false)$/		{ print "bool\n"; next; }
/^\d+$/				{ print "integer\n"; next; }
/^"[^"]*"$/			{ print "string\n"; next; }
				{ print "other\n"; next; }
'
}

append_dhcp_options() {
	local tuple="$1"

	# strip redundant "option:" prefix
	tuple="${tuple#option:}"

	local tag="${tuple%%,*}"
	local values="${tuple#$tag,}"

	local formatted value
	local IFS=$', \n'
	for value in $values; do
		# detect type of $value and quote if necessary
		case $(typeof "$value") in
		ip|bool|integer|string)
			;;
		other)
			value="\"$value\""
			;;
		esac
		formatted="$formatted${formatted:+, }$value"
	done
	echo " option $tag $formatted;"
}

gen_dhcp_subnet() {
	local cfg="$1"

	echo "subnet $NETWORK netmask $NETMASK {"
	echo " range $START $END;"
	echo " option subnet-mask $netmask;"
	if [ "$BROADCAST" != "0.0.0.0" ] ; then
		echo " option broadcast-address $BROADCAST;"
	fi
	if [ "$dynamicdhcp" -eq 0 ] ; then
		if [ "$authoritative" -eq 1 ] ; then
			echo " deny unknown-clients;"
		else
			echo " ignore unknown-clients;"
		fi
	fi
	if [ -n "$leasetime" ] ; then
		echo " default-lease-time $leasetime;"
		echo " max-lease-time $leasetime;"
	fi
	echo " option routers $gateway;"
	echo " option domain-name-servers $DNS;"
	config_list_foreach "$cfg" "dhcp_option" append_dhcp_options
	echo "}"
}

dhcpd_add() {
	local cfg="$1"
	local dhcp6range="::"
	local dynamicdhcp end gateway ifname ignore leasetime limit net netmask
	local proto networkid start subnet
	local IP NETMASK BROADCAST NETWORK PREFIX DNS START END

	config_get_bool ignore "$cfg" "ignore" 0
	[ "$ignore" = "0" ] || return 0

	config_get net "$cfg" "interface"
	[ -n "$net" ] || return 0

	config_get start "$cfg" "start"
	[ -n "$start" ] || return 0

	config_get limit "$cfg" "limit"
	[ -n "$limit" ] || return 0

	network_get_subnet subnet "$net" || return 0
	network_get_device ifname "$net" || return 0
	network_get_protocol proto "$net" || return 0

	[ static = "$proto" ] || return 0

	config_get_bool dynamicdhcp "$cfg" "dynamicdhcp" 1

	dhcp_ifs="$dhcp_ifs $ifname"

	eval "$(ipcalc.sh $subnet $start $limit)"

	config_get netmask "$cfg" "netmask" "$NETMASK"
	config_get leasetime "$cfg" "leasetime"
	if [ -n "$leasetime" ] ; then
		leasetime="$(time2seconds "$leasetime")"
		[ "$?" -ne 0 ] && return 1
	fi

	if network_get_dnsserver dnsserver "$net" ; then
		for dnsserv in $dnsserver ; do
			DNS="$DNS${DNS:+, }$dnsserv"
		done
	else
		DNS="$IP"
	fi

	if ! network_get_gateway gateway "$net" ; then
		gateway="$IP"
	fi

	gen_dhcp_subnet "$cfg" >> $config_file
}

general_config() {
	local always_broadcast boot_unknown_clients log_facility
	local default_lease_time max_lease_time
	config_get_bool always_broadcast "isc_dhcpd" "always_broadcast" 0
	config_get_bool authoritative "isc_dhcpd" "authoritative" 1
	config_get_bool boot_unknown_clients "isc_dhcpd" "boot_unknown_clients" 1
	config_get default_lease_time "isc_dhcpd" "default_lease_time" 3600
	config_get max_lease_time "isc_dhcpd" "max_lease_time" 86400
	config_get log_facility "isc_dhcpd" "log_facility"

	config_get domain "isc_dhcpd" "domain"

	[ $always_broadcast -eq 1 ] && echo "always-broadcast true;"
	[ $authoritative -eq 1 ] && echo "authoritative;"
	[ $boot_unknown_clients -eq 0 ] && echo "boot-unknown-clients false;"

	default_lease_time="$(time2seconds "$default_lease_time")"
	[ "$?" -ne 0 ] && return 1
	max_lease_time="$(time2seconds "$max_lease_time")"
	[ "$?" -ne 0 ] && return 1

	if [ -n "$log_facility" ] ; then
		echo "log-facility $log_facility;"
	fi
	echo "default-lease-time $default_lease_time;"
	echo "max-lease-time $max_lease_time;"

	[ -n "$domain" ] && echo "option domain-name \"$domain\";"

	rm -f /tmp/resolv.conf
	echo "# This file is generated by the DHCPD service" > /tmp/resolv.conf
	[ -n "$domain" ] && echo "domain $domain" >> /tmp/resolv.conf
	echo "nameserver 127.0.0.1" >> /tmp/resolv.conf
}

start_service() {
	if [ -n "$DHCPD_BOOT" ] ; then
		return 0
	fi

	if [ ! -e $lease_file ] ; then
		touch $lease_file
	fi

	local domain dhcp_ifs

	if [ -e "/etc/dhcpd.conf" ] ; then
		config_file="/etc/dhcpd.conf"
	else
		. /lib/functions/network.sh

		config_load dhcp
		local authoritative
		general_config > $config_file

		config_foreach dhcpd_add dhcp

		static_hosts >> $config_file

		[ -z "$dhcp_ifs" ] && return 0
	fi

	procd_open_instance
	procd_set_param command $PROG -q -f -cf $config_file -lf $lease_file $dhcp_ifs
	procd_close_instance
}

boot() {
	DHCPD_BOOT=1
	start "$@"
}

service_triggers()
{
	procd_add_reload_trigger "dhcp"
	procd_add_raw_trigger "interface.*" 3000 /etc/init.d/dhcpd reload
}