#!/bin/sh /etc/rc.common
# Copyright (C) 2007-2012 OpenWrt.org

START=60

USE_PROCD=1
PROG=/usr/sbin/dnsmasq

DNS_SERVERS=""
DOMAIN=""

ADD_LOCAL_DOMAIN=1
ADD_LOCAL_HOSTNAME=1

CONFIGFILE="/var/etc/dnsmasq.conf"
HOSTFILE="/tmp/hosts/dhcp"
TRUSTANCHORSFILE="/usr/share/dnsmasq/trust-anchors.conf"
TIMESTAMPFILE="/etc/dnsmasq.time"
TIMEVALIDFILE="/var/state/dnsmasqsec"

xappend() {
	local value="$1"

	echo "${value#--}" >> $CONFIGFILE
}

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        % 256))
        )"

        return 0
}

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_check() {
	local ifname="$1"
	local stamp="/var/run/dnsmasq.$ifname.dhcp"
	local rv=0

	[ -s "$stamp" ] && return $(cat "$stamp")

	udhcpc -n -q -s /bin/true -t 1 -i "$ifname" >&- && rv=1 || rv=0

	[ $rv -eq 1 ] && \
		logger -t dnsmasq \
			"found already running DHCP-server on interface '$ifname'" \
			"refusing to start, use 'option force 1' to override"

	echo $rv > "$stamp"
	return $rv
}

log_once() {
	pidof dnsmasq >/dev/null || \
		logger -t dnsmasq "$@"
}

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

append_parm() {
	local section="$1"
	local option="$2"
	local switch="$3"
	local default="$4"
	local _loctmp
	config_get _loctmp "$section" "$option" "$default"
	[ -z "$_loctmp" ] && return 0
	xappend "$switch=$_loctmp"
}

append_server() {
	xappend "--server=$1"
}

append_address() {
	xappend "--address=$1"
}

append_ipset() {
	xappend "--ipset=$1"
}

append_interface() {
	local ifname=$(uci_get_state network "$1" ifname "$1")
	xappend "--interface=$ifname"
}

append_notinterface() {
	local ifname=$(uci_get_state network "$1" ifname "$1")
	xappend "--except-interface=$ifname"
}

append_addnhosts() {
	xappend "--addn-hosts=$1"
}

append_bogusnxdomain() {
	xappend "--bogus-nxdomain=$1"
}

append_pxe_service() {
	xappend "--pxe-service=$1"
}

dnsmasq() {
	local cfg="$1"
	append_bool "$cfg" authoritative "--dhcp-authoritative"
	append_bool "$cfg" nodaemon "--no-daemon"
	append_bool "$cfg" domainneeded "--domain-needed"
	append_bool "$cfg" filterwin2k "--filterwin2k"
	append_bool "$cfg" nohosts "--no-hosts"
	append_bool "$cfg" nonegcache "--no-negcache"
	append_bool "$cfg" strictorder "--strict-order"
	append_bool "$cfg" logqueries "--log-queries=extra"
	append_bool "$cfg" noresolv "--no-resolv"
	append_bool "$cfg" localise_queries "--localise-queries"
	append_bool "$cfg" readethers "--read-ethers"
	append_bool "$cfg" dbus "--enable-dbus"
	append_bool "$cfg" boguspriv "--bogus-priv"
	append_bool "$cfg" expandhosts "--expand-hosts"
	config_get tftp_root "$cfg" "tftp_root"
	[ -d "$tftp_root" ] && append_bool "$cfg" enable_tftp "--enable-tftp"
	append_bool "$cfg" tftp_no_fail "--tftp-no-fail"
	append_bool "$cfg" nonwildcard "--bind-dynamic"
	append_bool "$cfg" fqdn "--dhcp-fqdn"
	append_bool "$cfg" proxydnssec "--proxy-dnssec"
	append_bool "$cfg" localservice "--local-service"
	append_bool "$cfg" quietdhcp "--quiet-dhcp"
	append_bool "$cfg" sequential_ip "--dhcp-sequential-ip"
	append_bool "$cfg" allservers "--all-servers"
	append_bool "$cfg" noping "--no-ping"

	append_parm "$cfg" dhcpscript "--dhcp-script"
	append_parm "$cfg" cachesize "--cache-size"
	append_parm "$cfg" dnsforwardmax "--dns-forward-max"
	append_parm "$cfg" port "--port"
	append_parm "$cfg" ednspacket_max "--edns-packet-max"
	append_parm "$cfg" dhcpleasemax "--dhcp-lease-max"
	append_parm "$cfg" "queryport" "--query-port"
	append_parm "$cfg" "minport" "--min-port"
	append_parm "$cfg" "maxport" "--max-port"
	append_parm "$cfg" "domain" "--domain"
	append_parm "$cfg" "local" "--server"
	config_list_foreach "$cfg" "server" append_server
	config_list_foreach "$cfg" "address" append_address
	config_list_foreach "$cfg" "ipset" append_ipset
	config_list_foreach "$cfg" "interface" append_interface
	config_list_foreach "$cfg" "notinterface" append_notinterface
	config_list_foreach "$cfg" "addnhosts" append_addnhosts
	config_list_foreach "$cfg" "bogusnxdomain" append_bogusnxdomain
	append_parm "$cfg" "leasefile" "--dhcp-leasefile" "/tmp/dhcp.leases"
	append_parm "$cfg" "resolvfile" "--resolv-file" "/tmp/resolv.conf.auto"
	append_parm "$cfg" "serversfile" "--servers-file"
	append_parm "$cfg" "tftp_root" "--tftp-root"
	append_parm "$cfg" "dhcp_boot" "--dhcp-boot"
	append_parm "$cfg" "local_ttl" "--local-ttl"
	append_parm "$cfg" "pxe_prompt" "--pxe-prompt"
	config_list_foreach "$cfg" "pxe_service" append_pxe_service
	config_get DOMAIN "$cfg" domain

	config_get_bool ADD_LOCAL_DOMAIN "$cfg" add_local_domain 1
	config_get_bool ADD_LOCAL_HOSTNAME "$cfg" add_local_hostname 1

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

	config_get leasefile $cfg leasefile "/tmp/dhcp.leases"
	[ -n "$leasefile" -a \! -e "$leasefile" ] && touch "$leasefile"
	config_get_bool cachelocal "$cfg" cachelocal 1

	config_get_bool noresolv "$cfg" noresolv 0
	if [ "$noresolv" != "1" ]; then
		config_get resolvfile "$cfg" resolvfile "/tmp/resolv.conf.auto"
		# So jail doesn't complain if file missing
		[ -n "$resolvfile" -a \! -e "$resolvfile" ] && touch "$resolvfile"
	fi

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

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

		local rebind_localhost
		config_get_bool rebind_localhost "$cfg" rebind_localhost 0
		[ $rebind_localhost -gt 0 ] && {
			log_once "Allowing 127.0.0.0/8 responses"
			xappend "--rebind-localhost-ok"
		}

		append_rebind_domain() {
			log_once "Allowing RFC1918 responses for domain $1"
			xappend "--rebind-domain-ok=$1"
		}

		config_list_foreach "$cfg" rebind_domain append_rebind_domain
	}

	config_get_bool dnssec "$cfg" dnssec 0
	[ "$dnssec" -gt 0 ] && {
		xappend "--conf-file=$TRUSTANCHORSFILE"
		xappend "--dnssec"
		[ -x /etc/init.d/sysntpd ] && {
			/etc/init.d/sysntpd enabled
			[ "$?" -ne 0 -o "$(uci_get system.ntp.enabled)" = "1" ] && {
				[ -f "$TIMEVALIDFILE" ] || xappend "--dnssec-no-timecheck"
			}
		}
		append_bool "$cfg" dnsseccheckunsigned "--dnssec-check-unsigned"
	}

	dhcp_option_add "$cfg" "" 0

	xappend "--dhcp-broadcast=tag:needs-broadcast"

	mkdir -p /tmp/hosts /tmp/dnsmasq.d
	xappend "--addn-hosts=/tmp/hosts"
	xappend "--conf-dir=/tmp/dnsmasq.d"
	xappend "--user=dnsmasq"
	xappend "--group=dnsmasq"

	echo >> $CONFIGFILE

	config_get_bool enable_tftp "$cfg" enable_tftp 0
	[ "$enable_tftp" -gt 0 ] && {
		config_get tftp_root "$cfg" tftp_root
		append EXTRA_MOUNT $tftp_root
	}
}

dhcp_subscrid_add() {
	local cfg="$1"

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

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

	xappend "--dhcp-subscrid=$networkid,$subscriberid"

	config_get_bool force "$cfg" force 0

	dhcp_option_add "$cfg" "$networkid" "$force"
}

dhcp_remoteid_add() {
	local cfg="$1"

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

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

	xappend "--dhcp-remoteid=$networkid,$remoteid"

	config_get_bool force "$cfg" force 0

	dhcp_option_add "$cfg" "$networkid" "$force"
}

dhcp_circuitid_add() {
	local cfg="$1"

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

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

	xappend "--dhcp-circuitid=$networkid,$circuitid"

	config_get_bool force "$cfg" force 0

	dhcp_option_add "$cfg" "$networkid" "$force"
}

dhcp_userclass_add() {
	local cfg="$1"

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

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

	xappend "--dhcp-userclass=$networkid,$userclass"

	config_get_bool force "$cfg" force 0

	dhcp_option_add "$cfg" "$networkid" "$force"
}

dhcp_vendorclass_add() {
	local cfg="$1"

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

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

	xappend "--dhcp-vendorclass=$networkid,$vendorclass"

	config_get_bool force "$cfg" force 0

	dhcp_option_add "$cfg" "$networkid" "$force"
}

dhcp_host_add() {
	local cfg="$1"

	config_get_bool force "$cfg" force 0

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

	config_get_bool enable "$cfg" enable 1
	[ "$enable" = "0" ] && return 0

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

	config_get_bool dns "$cfg" dns 0
	[ "$dns" = "1" -a -n "$ip" -a -n "$name" ] && {
		echo "$ip $name${DOMAIN:+.$DOMAIN}" >> $HOSTFILE
	}

	config_get mac "$cfg" mac
	if [ -n "$mac" ]; then
		# --dhcp-host=00:20:e0:3b:13:af,192.168.0.199,lap
		macs=""
		for m in $mac; do append macs "$m" ","; done
	else
		# --dhcp-host=lap,192.168.0.199
		[ -n "$name" ] || return 0
		macs="$name"
		name=""
	fi

	config_get tag "$cfg" tag

	if [ "$DHCPv6CAPABLE" -eq 1 ]; then
		config_get hostid "$cfg" hostid
		if [ -n "$hostid" ]; then
			hex_to_hostid hostid "$hostid"
		fi
	fi

	config_get_bool broadcast "$cfg" broadcast 0
	[ "$broadcast" = "0" ] && broadcast=

	config_get leasetime "$cfg" leasetime

	xappend "--dhcp-host=$macs${networkid:+,net:$networkid}${broadcast:+,set:needs-broadcast}${tag:+,set:$tag}${ip:+,$ip${hostid:+,[::$hostid]}}${name:+,$name}${leasetime:+,$leasetime}"
}

dhcp_tag_add() {
	local cfg="$1"

	tag="$cfg"

	[ -n "$tag" ] || return 0

	config_get_bool force "$cfg" force 0
	[ "$force" = "0" ] && force=

	config_get option "$cfg" dhcp_option
	for o in $option; do
		xappend "--dhcp-option${force:+-force}=tag:$tag,$o"
	done
}

dhcp_mac_add() {
	local cfg="$1"

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

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

	xappend "--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 "$cfg" servername
	config_get serveraddress "$cfg" serveraddress

	[ -n "$serveraddress" -a ! -n "$servername" ] && return 0

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

	config_get_bool force "$cfg" force 0

	dhcp_option_add "$cfg" "$networkid" "$force"
}


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

	config_get dhcpv4 "$cfg" dhcpv4
	[ "$dhcpv4" != "disabled" ] || return 0

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

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

	[ "$cachelocal" = "0" ] && network_get_dnsserver dnsserver "$net" && {
		DNS_SERVERS="$DNS_SERVERS $dnsserver"
	}

	append_bool "$cfg" ignore "--no-dhcp-interface=$ifname" && return 0

	# Do not support non-static interfaces for now
	[ static = "$proto" ] || return 0

	# Override interface netmask with dhcp config if applicable
	config_get netmask "$cfg" netmask "${subnet##*/}"

	#check for an already active dhcp server on the interface, unless 'force' is set
	config_get_bool force "$cfg" force 0
	[ $force -gt 0 ] || dhcp_check "$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}"
	[ "$limit" -gt 0 ] && limit=$((limit-1))
	eval "$(ipcalc.sh "${subnet%%/*}" $netmask $start $limit)"
	if [ "$dynamicdhcp" = "0" ]; then END="static"; fi
	xappend "--dhcp-range=$networkid,$START,$END,$NETMASK,$leasetime${options:+ $options}"

	dhcp_option_add "$cfg" "$networkid"
}

dhcp_option_add() {
	local cfg="$1"
	local networkid="$2"
	local force="$3"

	[ "$force" = "0" ] && force=

	config_get dhcp_option "$cfg" dhcp_option
	for o in $dhcp_option; do
		xappend "--dhcp-option${force:+-force}=${networkid:+$networkid,}$o"
	done

}

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

	config_get names "$cfg" name "$2"
	[ -n "$names" ] || return 0

	config_get ip "$cfg" ip "$3"
	[ -n "$ip" ] || return 0

	for name in $names; do
		record="${record:+$record }$name"
	done

	echo "$ip $record" >> $HOSTFILE
}

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 "$cfg" port
	[ -n "$port" ] || return 0

	config_get class "$cfg" class
	config_get weight "$cfg" weight

	local service="$srv,$target,$port${class:+,$class${weight:+,$weight}}"

	xappend "--srv-host=$service"
}

dhcp_mx_add() {
	local cfg="$1"
	local domain relay pref

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

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

	config_get pref "$cfg" pref 0

	local service="$domain,$relay,$pref"

	xappend "--mx-host=$service"
}

dhcp_cname_add() {
	local cfg="$1"
	local cname target

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

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

	xappend "--cname=${cname},${target}"
}

dhcp_hostrecord_add() {
	local cfg="$1"
	local names addresses record val

	config_get names "$cfg" name "$2"
	if [ -z "$names" ]; then
		return 0
	fi

	config_get addresses "$cfg" ip "$3"
	if [ -z "$addresses" ]; then
		return 0
	fi

	for val in $names $addresses; do
		record="${record:+$record,}$val"
	done

	xappend "--host-record=$record"
}

dhcp_relay_add() {
	local cfg="$1"
	local local_addr server_addr interface

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

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

	config_get interface "$cfg" interface
	if [ -z "$interface" ]; then
		xappend "--dhcp-relay=$local_addr,$server_addr"
	else
		xappend "--dhcp-relay=$local_addr,$server_addr,$interface"
	fi
}

service_triggers()
{
	procd_add_reload_trigger "dhcp"
}

boot() {
	# Will be launched through hotplug
	return 0
}

start_service() {
	include /lib/functions

	config_load dhcp

	# before we can call xappend
	mkdir -p /var/run/dnsmasq/
	mkdir -p $(dirname $CONFIGFILE)
	mkdir -p /var/lib/misc
	touch /tmp/dhcp.leases

	[ -f "$TIMESTAMPFILE" ] && rm -f "$TIMESTAMPFILE"

	echo "# auto-generated config file from /etc/config/dhcp" > $CONFIGFILE
	echo "# auto-generated config file from /etc/config/dhcp" > $HOSTFILE

	# if we did this last, we could override auto-generated config
	[ -f /etc/dnsmasq.conf ] && {
		xappend "--conf-file=/etc/dnsmasq.conf"
	}

	$PROG --version | grep -osqE "^Compile time options:.* DHCPv6( |$)" && DHCPv6CAPABLE=1 || DHCPv6CAPABLE=0

	args=""
	config_foreach dnsmasq dnsmasq
	config_foreach dhcp_host_add host
	echo >> $CONFIGFILE
	config_foreach dhcp_boot_add boot
	config_foreach dhcp_mac_add mac
	config_foreach dhcp_tag_add tag
	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_hostrecord_add hostrecord
	config_foreach dhcp_relay_add relay

	# add own hostname
	[ $ADD_LOCAL_HOSTNAME -eq 1 ] && {
		local lanaddr lanaddr6
		local ulaprefix="$(uci_get network @globals[0] ula_prefix)"
		local hostname="$(uci_get system @system[0] hostname Lede)"

		network_get_ipaddr lanaddr "lan" && {
			dhcp_domain_add "" "$hostname" "$lanaddr"
		}

		[ -n "$ulaprefix" ] && network_get_ipaddrs6 lanaddr6 "lan" && {
			for lanaddr6 in $lanaddr6; do
				case "$lanaddr6" in
					"${ulaprefix%%:/*}"*)
						dhcp_domain_add "" "$hostname" "$lanaddr6"
					;;
				esac
			done
		}
	}

	echo >> $CONFIGFILE
	config_foreach dhcp_srv_add srvhost
	config_foreach dhcp_mx_add mxhost
	echo >> $CONFIGFILE

	config_get odhcpd_is_active odhcpd maindhcp
	if [ "$odhcpd_is_active" != "1" ]; then
		config_foreach dhcp_add dhcp
	fi

	echo >> $CONFIGFILE
	config_foreach dhcp_cname_add cname
	echo >> $CONFIGFILE

	rm -f /tmp/resolv.conf
	[ $ADD_LOCAL_DOMAIN -eq 1 ] && [ -n "$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

	procd_open_instance
	procd_set_param command $PROG -C $CONFIGFILE -k -x /var/run/dnsmasq/dnsmasq.pid
	procd_set_param file $CONFIGFILE
	procd_set_param respawn

	procd_add_jail dnsmasq ubus log
	procd_add_jail_mount $CONFIGFILE $TRUSTANCHORSFILE $HOSTFILE /etc/passwd /etc/group /etc/TZ /dev/null /dev/urandom /etc/dnsmasq.conf /tmp/dnsmasq.d /tmp/resolv.conf.auto /etc/hosts /etc/ethers $EXTRA_MOUNT
	procd_add_jail_mount_rw /var/run/dnsmasq/ /tmp/dhcp.leases

	procd_close_instance
}

reload_service() {
	rc_procd start_service "$@"
	return 0
}

stop_service() {
	[ -f /tmp/resolv.conf ] && {
		rm -f /tmp/resolv.conf
		ln -s /tmp/resolv.conf.auto /tmp/resolv.conf
	}
	rm -f /var/run/dnsmasq.*.dhcp
}