#!/bin/sh /etc/rc.common
# Copyright (C) 2007 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"
}

append_bool() {
	local section="$1"
	local option="$2"
	local value="$3"
	local _tmp
	config_get_bool _tmp "$section" "$option"
	[ "$_tmp" -gt 0 ] && append args "$3"
}

dnsmasq() {
	local cfg="$1"
	append_bool "$cfg" authoritative "-K"
	append_bool "$cfg" nodaemon "-d"
	append_bool "$cfg" domainneeded "-D"
	append_bool "$cfg" filterwin2k "-f"
	append_bool "$cfg" nohosts "-I $nohosts"
	append_bool "$cfg" nonegcache "-N"
	append_bool "$cfg" strictorder "-o"
	append_bool "$cfg" logqueries "-q"
	append_bool "$cfg" noresolv "-I $noresolv"
	append_bool "$cfg" localise_queries "-I $localise_queries"
	append_bool "$cfg" readethers "-Z"
	append_bool "$cfg" dbus "-l"
	
	config_get dnsforwardmax "$cfg" dnsforwardmax
	dnsforwardmax="${dnsforwardmax:-150}"
	append args "-0 $dnsforwardmax"
	
	config_get port "$cfg" port
	port="${port:-53}"
	append args "-p $port"
	
	config_get ednspacket_max "$cfg" ednspacket_max
	ednspacket_max="${ednspacket_max:-1280}"
	append args "-P $ednspacket_max"
	
	config_get dhcpleasemax "$cfg" dhcpleasemax
	dhcpleasemax="${dhcpleasemax:-150}"
	append args "-X $dhcpleasemax"
	
	config_get addnhosts "$cfg" addnhosts
	config_get interface "$cfg" interface
	config_get exceptinterface "$cfg" exceptinterface
	config_get queryport "$cfg" queryport
	config_get domain "$cfg" domain
}

dhcp_subscrid_add() {
	local cfg="$1"
	
	config_get name "$cfg" name
	[ -n "$name" ] || return 0
	
	config_get subscriberid "$cfg" subscriberid
	[ -n "$subscriberid" ] || return 0
	
	append args "--dhcp-subscrid=$name,$subscriberid"
	
	dhcp_option_add "$cfg" "$name"
}

dhcp_remoteid_add() {
	local cfg="$1"

	config_get name "$cfg" name
	[ -n "$name" ] || return 0
	
	config_get remoteid "$cfg" remoteid
	[ -n "$remoteid" ] || return 0
	
	append args "--dhcp-remoteid=$name,$remoteid"
	
	dhcp_option_add "$cfg" "$name"
}

dhcp_circuitid_add() {
	local cfg="$1"
	
	config_get name "$cfg" name
	[ -n "$name" ] || return 0
	
	config_get circuitid "$cfg" circuitid
	[ -n "$circuitid" ] || return 0
	
	append args "--dhcp-circuitid=$name,$circuitid"
	
	dhcp_option_add "$cfg" "$name"
}

dhcp_userclass_add() {
	local cfg="$1"
	
	config_get name "$cfg" name
	[ -n "$name" ] || return 0
	
	config_get userclass "$cfg" userclass
	[ -n "$userclass" ] || return 0
	
	append args "--dhcp-userclass=$name,$userclass"
	
	dhcp_option_add "$cfg" "$name"
}

dhcp_vendorclass_add() {
	local cfg="$1"
	
	config_get name "$cfg" name
	[ -n "$name" ] || return 0
	
	config_get vendorclass "$cfg" vendorclass
	[ -n "$vendorclass" ] || return 0
	
	append args "--dhcp-vendorclass=$name,$vendorclass"
	
	dhcp_option_add "$cfg" "$name"
}

dhcp_host_add() {
	local cfg="$1"
	
	config_get name "$cfg" name
	[ -n "$name" ] || return 0
	
	config_get mac "$cfg" mac
	[ -n "$mac" ] || return 0

	
	append args "--dhcp-host=$mac,$ip"
	
	dhcp_option_add "$cfg" "$name"
}

dhcp_mac_add() {
	local cfg="$1"
	
	config_get name "$cfg" name
	[ -n "$name" ] || return 0
	
	config_get mac "$cfg" mac
	[ -n "$mac" ] || return 0
	
	append args "--dhcp-mac=$name,$mac"
	
	dhcp_option_add "$cfg" "$name"
}

dhcp_add() {
	local cfg="$1"
	config_get net "$cfg" interface
	[ -n "$net" ] || return 0

	config_get name "$cfg" name
	[ -n "$name" ] || name="$net"

	config_get ifname "$net" ifname
	[ -n "$ifname" ] || return 0

	append_bool "$cfg" ignore "-I $ifname"

	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 $end)"
	append args "--dhcp-range=$name,$START,$END,$NETMASK,$leasetime${options:+ $options}"
	
	dhcp_option_add "$cfg" "$name"
}

dhcp_option_add () {
	local cfg="$1"
	local name="$2"
	
	for count in $(seq 0 100); do
		eval current_value=\$CONFIG_"$cfg"_dhcp"$count"
		if [ -z "$current_value" ]; then
			let "count-=1"
			break
		fi
		append args "-O $name","$current_value"
	done

}

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

	args=""
	config_foreach dnsmasq dnsmasq
	config_foreach dhcp_host_add host
	config_foreach dhcp_mac_add mac
	config_foreach dhcp_vendorclass_add vendorclass
	config_foreach dhcp_userclass_add userclass
	config_foreach dhcp_circuitid_add circuitid
	config_foreach dhcp_remoteid_add remoteid
	config_foreach dhcp_subscrid_add subscrid
	config_foreach dhcp_add dhcp

	/usr/sbin/dnsmasq $args && {
		rm -f /tmp/resolv.conf
		cat > /tmp/resolv.conf <<EOF
nameserver 127.0.0.1
search lan
EOF
	}
}

stop() {
	killall dnsmasq
}