#!/bin/sh /etc/rc.common
# Copyright (C) 2007 OpenWrt.org

START=60
DNS_SERVERS=""
DOMAIN=""

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="$3"
	local _loctmp
	config_get_bool _loctmp "$section" "$option"
	[ "$_loctmp" -gt 0 ] && append args "$value"
}

append_parm() {
	local section="$1"
	local option="$2"
	local switch="$3"
	local _loctmp
	config_get _loctmp "$section" "$option"
	[ -z "$_loctmp" ] && return 0
	append args "$switch $_loctmp"
}

append_server() {
	append args "-S $1"
}

append_interface() {
	append args "-i $1"
}

append_notinterface() {
	append args "-I $1"
}

append_addnhosts() {
	append args "-H $1"
}

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 "-h"
	append_bool "$cfg" nonegcache "-N"
	append_bool "$cfg" strictorder "-o"
	append_bool "$cfg" logqueries "-q"
	append_bool "$cfg" noresolv "-R"
	append_bool "$cfg" localise_queries "-y"
	append_bool "$cfg" readethers "-Z"
	append_bool "$cfg" dbus "-1"
	append_bool "$cfg" boguspriv "-b"
	append_bool "$cfg" expandhosts "-E"
	append_bool "$cfg" enable_tftp "--enable-tftp"
	append_bool "$cfg" nonwildcard "-z"

	append_parm "$cfg" dnsforwardmax "-0"
	append_parm "$cfg" port "-p"
	append_parm "$cfg" ednspacket_max "-P"
	append_parm "$cfg" dhcpleasemax "-X"
	append_parm "$cfg" "queryport" "-Q"
	append_parm "$cfg" "domain" "-s"
	append_parm "$cfg" "local" "-S"
	config_list_foreach "$cfg" "server" append_server
	config_list_foreach "$cfg" "interface" append_interface
	config_list_foreach "$cfg" "notinterface" append_notinterface
	config_list_foreach "$cfg" "addnhosts" append_addnhosts
	append_parm "$cfg" "leasefile" "-l"
	append_parm "$cfg" "resolvfile" "-r"
	append_parm "$cfg" "tftp_root" "--tftp-root"
	append_parm "$cfg" "dhcp_boot" "--dhcp-boot"

	config_get DOMAIN "$cfg" domain

	config_get_bool readethers "$cfg" readethers
	[ "$readethers" = "1" ] && [ -e "/etc/ethers" ] || touch /etc/ethers

	config_get leasefile $cfg leasefile
	[ -e "$leasefile" ] || touch "$leasefile"
	config_get_bool cachelocal "$cfg" cachelocal 1

	config_get hostsfile "$cfg" dhcphostsfile
	[ -e "$hostsfile" ] && append args "--dhcp-hostsfile=$hostsfile"

	local rebind
	config_get_bool rebind "$cfg" rebind_protection 1
	[ $rebind -gt 0 ] && {
		logger -t dnsmasq \
			"DNS rebinding protection is active," \
			"will discard upstream RFC1918 responses!"
		append args "--stop-dns-rebind"

		local rebind_localhost
		config_get_bool rebind_localhost "$cfg" rebind_localhost 0
		[ $rebind_localhost -gt 0 ] && {
			logger -t dnsmasq "Allowing 127.0.0.0/8 responses"
			append args "--rebind-localhost-ok"
		}

		append_rebind_domain() {
			logger -t dnsmasq "Allowing RFC1918 responses for domain $1"
			append args "--rebind-domain-ok=$1"
		}

		config_list_foreach "$cfg" rebind_domain append_rebind_domain
	}
}

dhcp_subscrid_add() {
	local cfg="$1"

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

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

	append args "--dhcp-subscrid=$networkid,$subscriberid"

	dhcp_option_add "$cfg" "$networkid"
}

dhcp_remoteid_add() {
	local cfg="$1"

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

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

	append args "--dhcp-remoteid=$networkid,$remoteid"

	dhcp_option_add "$cfg" "$networkid"
}

dhcp_circuitid_add() {
	local cfg="$1"

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

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

	append args "--dhcp-circuitid=$networkid,$circuitid"

	dhcp_option_add "$cfg" "$networkid"
}

dhcp_userclass_add() {
	local cfg="$1"

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

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

	append args "--dhcp-userclass=$networkid,$userclass"

	dhcp_option_add "$cfg" "$networkid"
}

dhcp_vendorclass_add() {
	local cfg="$1"

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

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

	append args "--dhcp-vendorclass=$networkid,$vendorclass"

	dhcp_option_add "$cfg" "$networkid"
}

dhcp_host_add() {
	local cfg="$1"

	config_get name "$cfg" name

	config_get networkid "$cfg" networkid
	[ -n "$networkid" ] && dhcp_option_add "$cfg" "$networkid"

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

	macs=""
	config_get mac "$cfg" mac
	for m in $mac; do append macs "$m" ","; done
	[ -n "$macs" ] || return 0

	append args "--dhcp-host=$macs,${networkid:+net:$networkid,}$ip${name:+,$name}"
}

dhcp_mac_add() {
	local cfg="$1"

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

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

	append args "--dhcp-mac=$networkid,$mac"

	dhcp_option_add "$cfg" "$networkid"
}

dhcp_boot_add() {
	local cfg="$1"

	config_get networkid "$cfg" networkid

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

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

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

	append args "--dhcp-boot=${networkid:+net:$networkid,}$filename,$servername,$serveraddress"

	dhcp_option_add "$cfg" "$networkid"
}


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

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

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

	config_get dnsserver "$net" dns
	[ "$cachelocal" = "0" -a -n "$dnsserver" ] && {
		DNS_SERVERS="$DNS_SERVERS $dnsserver"
	}

	append_bool "$cfg" ignore "-2 '$ifname'" && return 0

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

	config_get ipaddr "$net" ipaddr
	config_get netmask "$cfg" netmask
	[ -n "$netmask" ] || config_get netmask "$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 -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
	config_get_bool dynamicdhcp "$cfg" dynamicdhcp 1

	leasetime="${leasetime:-12h}"
	start="$(dhcp_calc "${start:-100}")"
	limit="${limit:-150}"
	eval "$(ipcalc.sh $ipaddr $netmask $start $limit)"
	if [ "$dynamicdhcp" = "0" ]; then END="static"; fi
	append args "--dhcp-range=$networkid,$START,$END,$NETMASK,$leasetime${options:+ $options}"

	dhcp_option_add "$cfg" "$networkid"
}

dhcp_option_add() {
	local cfg="$1"
	local networkid="$2"

	config_get dhcp_option "$cfg" dhcp_option
	for o in $dhcp_option; do
		append args "-O $networkid","$o"
	done

}

dhcp_domain_add() {
	local cfg="$1"
	local ip name names

	config_get names "$cfg" name
	[ -n "$names" ] || return 0

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

	local oIFS="$IFS"; IFS="."; set -- $ip; IFS="$oIFS"
	local raddr="${4:+$4.$3.$2.$1.in-addr.arpa}"

	for name in $names; do
		local fqdn="$name"

		[ "${fqdn%.*}" == "$fqdn" ] && \
			fqdn="$fqdn${DOMAIN:+.$DOMAIN}"

		append args "-A /$fqdn/$ip"
		
		[ -n "$raddr" ] && {
			append args "--ptr-record=$raddr,$fqdn"
			raddr=""
		}
	done
}

dhcp_srv_add() {
	local cfg="$1"

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

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

	config_get port "$cfg" port

	local service="$srv,$target"
	[ -n "$port" ] && service="$service,$port"

	append args "-W $service"
}

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

	args=""
	config_foreach dnsmasq dnsmasq
	config_foreach dhcp_host_add host
	config_foreach dhcp_boot_add boot
	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_domain_add domain
	config_foreach dhcp_srv_add srvhost
	config_foreach dhcp_add dhcp

	/usr/sbin/dnsmasq $args && {
		rm -f /tmp/resolv.conf
		[ -n "$DOMAIN" ] && echo "search $DOMAIN" >> /tmp/resolv.conf
		DNS_SERVERS="$DNS_SERVERS 127.0.0.1"
		for DNS_SERVER in $DNS_SERVERS ; do
			echo "nameserver $DNS_SERVER" >> /tmp/resolv.conf
		done
	}
}

stop() {
	[ -f /tmp/resolv.conf ] && {
		rm -f /tmp/resolv.conf
		ln -s /tmp/resolv.conf.auto /tmp/resolv.conf
	}
	killall dnsmasq
	return 0
}