#!/bin/sh /etc/rc.common
# Copyright (C) 2006 OpenWrt.org

START=60

dhcp_calc() {
	local ip="$1"
	local res=0
	
	while [ -n "$ip" ]; do
		part="${ip%%.*}"
		res="$(($res * 256))"
		res="$(($res + $part))"
		[ "${ip%.*}" != "$ip" ] && ip="${ip#*.}" || ip=
	done
	echo "$res"
}

dhcp_add() {
	local cfg="$1"

	config_get net "$cfg" interface
	[ -n "$net" ] || return 0
	
	config_get ifname "$net" ifname
	[ -n "$ifname" ] || return 0
	
	config_get_bool ignore "$cfg" ignore
	[ "$ignore" -gt 0 ] && {
		append args "-I $ifname"
		return 0
	}
	
	config_get proto "$net" proto
	[ static = "$proto" ] || return 0
	
	config_get ipaddr "$net" ipaddr
	config_get netmask "$net" netmask

	# check for an already active dhcp server on the interface, unless 'force' is set
	config_get_bool force "$cfg" force 0
	[ "$force" -gt 0 ] || {
		udhcpc -n -q -R -s /bin/true -t 1 -i $ifname >&- && return 0
	}
	
	config_get start "$cfg" start
	config_get limit "$cfg" limit
	config_get leasetime "$cfg" leasetime
	config_get options "$cfg" options

	leasetime="${leasetime:-12h}"
	start="$(dhcp_calc "${start:-100}")"
	limit="$((${limit:-150} + 1))"
	eval "$(ipcalc.sh $ipaddr $netmask $start $limit)"
	append args "-F $START,$END,$NETMASK,$leasetime${options:+ $options}"
}

start() {
	include /lib/network
	scan_interfaces
	config_load /var/state/network
	config_load dhcp

	args=""
	config_foreach dhcp_add dhcp
	
	dnsmasq $args && {
		rm -f /tmp/resolv.conf
		cat > /tmp/resolv.conf <<EOF
nameserver 127.0.0.1
search lan
EOF
	}
}

stop() {
	killall dnsmasq
}