#!/bin/sh
# $Id$
# $OpenBSD: dhclient-script,v 1.6 2004/05/06 18:22:41 claudio Exp $
# $FreeBSD: src/sbin/dhclient/dhclient-script,v 1.4 2005/06/10 03:41:18 brooks Exp $
#
# Copyright (c) 2003 Kenneth R Westerback <krw@openbsd.org>
#
# Permission to use, copy, modify, and distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
# OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
#

LOG_PREFIX_DHCPC="DHCP Client"
_logger() {
	case "${1}" in
	"LOG_EMERG")
		loglvl="emerg"
		logpri="EMERGENCY"
		;;
	"LOG_ALERT")
		loglvl="alert"
		logpri="ALERT"
		;;
	"LOG_CRIT")
		loglvl="crit"
		logpri="CRITICAL"
		;;
	"LOG_ERR")
		loglvl="err"
		logpri="ERROR"
		;;
	"LOG_WARNING")
		loglvl="warning"
		logpri="WARNING"
		;;
	"LOG_NOTICE")
		loglvl="notice"
		logpri="NOTICE"
		;;
	"LOG_INFO")
		loglvl="info"
		logpri="INFO"
		;;
	"LOG_DEBUG")
		loglvl="debug"
		logpri="DEBUG"
		;;
	*)
		loglvl="debug"
		logpri="DEBUG"
		;;
	esac

	if [ -z "${2}" ]; then
		logmsg=""
	else
		logmsg="${2}"
	fi

	if [ -x /usr/bin/logger ]; then
		/usr/bin/logger -s -p "user.${loglvl}" -t dhclient "${logpri} [${LOG_PREFIX_DHCPC}] ${logmsg}"
	else
		echo "${logpri} [${LOG_PREFIX_DHCPC}] ${logmsg}"
	fi
}

HOSTNAME=/bin/hostname
ROUTE=/sbin/route
ARP=/usr/sbin/arp
IFCONFIG=/sbin/ifconfig

LOCALHOST=127.0.0.1

#
# Helper functions that implement common actions.
#

check_hostname() {
	current_hostname=`$HOSTNAME`
	if [ -z "$current_hostname" ] || \
	   [ "$current_hostname" = "$old_host_name" -a \
	     "$new_hostname" != "$old_host_name" ]; then
		_logger "LOG_NOTICE" "New Hostname (${interface}): ${new_host_name}"
		$HOSTNAME "$new_host_name"
	fi
}

arp_flush() {
	$ARP -ad -i "$interface" >/dev/null 2>&1
}

delete_old_address() {
	/bin/rm -f "/var/db/${interface}_ip"
	eval $IFCONFIG "$interface" inet -alias "$old_ip_address" "$medium"
}

add_new_address() {

	_logger "LOG_NOTICE" "Starting add_new_address()"

	_logger "LOG_NOTICE" "ifconfig ${interface} inet ${new_ip_address} netmask ${new_subnet_mask} broadcast ${new_broadcast_address} ${medium}"

	eval $IFCONFIG "$interface" \
		inet "$new_ip_address" \
		netmask "$new_subnet_mask" \
		broadcast "$new_broadcast_address" \
		"$medium"

	_logger "LOG_NOTICE" "New IP Address (${interface}): ${new_ip_address}"
	_logger "LOG_NOTICE" "New Subnet Mask (${interface}): ${new_subnet_mask}"
	_logger "LOG_NOTICE" "New Broadcast Address (${interface}): ${new_broadcast_address}"
	_logger "LOG_NOTICE" "New Routers (${interface}): ${new_routers}"


	# This is necessary otherwise dpinger will try to ping all 1s address
	if [ -n "$new_routers" ] && [ "$new_routers" != "255.255.255.255" ]; then
		echo "$new_routers" > "/tmp/${interface}_router"
		/bin/rm -f "/tmp/${interface}_router.last"
	fi
	echo "$new_ip_address" > "/var/db/${interface}_ip"
}

delete_old_alias() {
	if [ -n "$alias_ip_address" ]; then
		$IFCONFIG "$interface" inet -alias "$alias_ip_address" > /dev/null 2>&1
		$ROUTE delete "$alias_ip_address" "$LOCALHOST" > /dev/null 2>&1
	fi
}

add_new_alias() {
	if [ -n "$alias_ip_address" ]; then
		$IFCONFIG "$interface" inet alias "$alias_ip_address" netmask \
		    "$alias_subnet_mask"
		$ROUTE add "$alias_ip_address" "$LOCALHOST"
	fi
}

fill_classless_routes() {
	set $1
	while [ $# -ge 5 ]; do
		if [ "$1" -eq 0 ]; then
			route="default"
		elif [ "$1" -le 8 ]; then
			route="$2.0.0.0/$1"
			shift
		elif [ "$1" -le 16 ]; then
			route="$2.$3.0.0/$1"
			shift; shift
		elif [ "$1" -le 24 ]; then
			route="$2.$3.$4.0/$1"
			shift; shift; shift
		else
			route="$2.$3.$4.$5/$1"
			shift; shift; shift; shift
		fi
		shift
		router="$1.$2.$3.$4"
		classless_routes="$classless_routes $route $router"
		shift; shift; shift; shift
	done
}

delete_old_routes() {
	_logger "LOG_NOTICE" "Deleting old routes"

	if [ -n "$old_classless_routes" ]; then
		fill_classless_routes "$old_classless_routes"
		set $classless_routes
		while [ $# -gt 1 ]; do
			$ROUTE delete "$1" "$2"
			shift; shift
		done
		return 0;
	fi

	# Only allow the default route to be overridden if it's on our own interface
	if [ -f "/tmp/${interface}_defaultgw" ]; then
		for router in $old_routers; do
			#  delete local route to the router ip address.
			#  cleans up our route to a gateway possibly outside of the assigned subnet
			$ROUTE delete -host "$router" -iface "$interface"

			$ROUTE delete default "$router" >/dev/null 2>&1
		done
		if [ -f "/tmp/${interface}_router" ]; then
			/bin/mv "/tmp/${interface}_router" "/tmp/${interface}_router.last"
		fi
	fi

	if [ -n "$old_static_routes" ]; then
		set $old_static_routes
		while [ $# -gt 1 ]; do
			$ROUTE delete "$1" "$2"
			shift; shift
		done
		if [ -f "/tmp/${interface}_router" ]; then
			/bin/mv "/tmp/${interface}_router" "/tmp/${interface}_router.last"
		fi
	fi

	arp_flush
}

add_new_routes() {
	_logger "LOG_NOTICE" "Adding new routes to interface: ${interface}"

	# RFC 3442: If the DHCP server returns both a Classless Static
	# Routes option and a Router option, the DHCP client MUST ignore
	# the Router option.
	#
	# DHCP clients that support this option (Classless Static Routes)
	# MUST NOT install the routes specified in the Static Routes
	# option (option code 33) if both a Static Routes option and the
	# Classless Static Routes option are provided.
	if [ -n "$new_classless_routes" ]; then
		fill_classless_routes "$new_classless_routes"
		_logger "LOG_NOTICE" "New Classless Static Routes (${interface}): ${classless_routes}"
		set $classless_routes
		while [ $# -gt 1 ]; do
			if [ "0.0.0.0" = "$2" ]; then
				$ROUTE add "$1" -iface "$interface"
			else
				$ROUTE add "$1" "$2"
			fi
			shift; shift
		done
		return
	fi

	ADDED_ROUTE=no
	# Only allow the default route to be overridden if it's on our own interface
	if [ -f "/tmp/${interface}_defaultgw" ]; then
		OLD_ROUTER=$(cat "/tmp/${interface}_defaultgw")
		$ROUTE delete default "${OLD_ROUTER}"
		for router in $new_routers; do
			if [ "$new_ip_address" = "$router" ] || [ "$router" = "255.255.255.255" ]; then
				$ROUTE add default -iface "$interface"
				_logger "LOG_NOTICE" "${ROUTE} add default -iface \"${interface}\""
				# NOTE: Do not activate this for all ones address since pf(4) will try to forward packets to it.
				if [ "$new_ip_address" = "$router" ]; then
					echo "$router" > "/tmp/${interface}_router"
					/bin/rm -f "/tmp/${interface}_router.last"
				fi
			else
				#  add local route to the router ip address.
				#  this will not cause any harm if the router is within the subnet
				#  but it will prevent route troubles if the router is outside of the subnet
				#  this is useful for captive subnets or similar gateway out-of-subnet situations
				$ROUTE add -host "$router" -iface "$interface"
				_logger "LOG_NOTICE" "${ROUTE} add -host \"${router}\" -iface \"${interface}\""

				$ROUTE add default "$router"
				_logger "LOG_NOTICE" "${ROUTE} add default \"${router}\""
				echo "$router" > "/tmp/${interface}_router"
				/bin/rm -f "/tmp/${interface}_router.last"
			fi
			ADDED_ROUTE=yes
			# 2nd and subsequent default routers error out, so explicitly
			# stop processing the list after the first one.
			break
		done
	fi

	if [ -n "$new_static_routes" ]; then
		_logger "LOG_NOTICE" "New Static Routes (${interface}): ${new_static_routes}"
		set $new_static_routes
		while [ $# -gt 1 ]; do
			$ROUTE add "$1" "$2"
			if [ "$ADDED_ROUTE" = "no" ]; then
				echo "$2" > "/tmp/${interface}_router"
				/bin/rm -f "/tmp/${interface}_router.last"
			fi
			shift; shift
		done
	fi
}

add_new_resolv_conf() {
	_logger "LOG_NOTICE" "Creating resolv.conf"
	if [ -f "/var/etc/nameserver_$interface" ]; then
		# Remove old entries
		for nameserver in `cat "/var/etc/nameserver_$interface"`; do
			$ROUTE delete "$nameserver" >/dev/null 2>&1
		done
	fi
	if [ -n "$new_domain_name_servers" ]; then
		/bin/rm -f "/var/etc/nameserver_$interface"
		ALLOWOVERRIDE=$(/usr/local/sbin/read_xml_tag.sh boolean system/dnsallowoverride)
		for nameserver in $new_domain_name_servers; do
			# Add a route to the nameserver out the correct interface
			# so that multiple wans work correctly with multiple dns
			# also backup the nameserver for later route removal
			if [ "$ALLOWOVERRIDE" = "true" ]; then
				echo "$nameserver" >> "/var/etc/nameserver_$interface"
				$ROUTE add "$nameserver" -iface "$interface"
			fi
		done
		echo "$new_domain_name" > "/var/etc/searchdomain_$interface"
	fi

	return 0
}

# Notify rc.newwanip of changes to an interface
notify_rc_newwanip() {
	/usr/local/sbin/pfSctl -c "interface newip $interface"
}

#
# Start of active code.
#
exit_status=0

# Invoke the local dhcp client enter hooks, if they exist.
if [ -f /etc/dhclient-enter-hooks ]; then
	_logger "LOG_NOTICE" "dhclient-enter-hooks"
	. /etc/dhclient-enter-hooks
	# allow the local script to abort processing of this state
	# local script must set exit_status variable to nonzero.
	if [ $exit_status -ne 0 ]; then
		exit $exit_status
	fi
fi

_logger "LOG_NOTICE" "${reason}"
case $reason in
MEDIUM)
	eval "$IFCONFIG $interface $medium"
	/bin/sleep 1
	;;

PREINIT)
	delete_old_alias
	eval "$IFCONFIG $interface up"
	if [ -f "/tmp/${interface}_router" ]; then
		/bin/mv "/tmp/${interface}_router" "/tmp/${interface}_router.last"
	fi
	;;

ARPCHECK|ARPSEND)
	;;

BOUND|RENEW|REBIND|REBOOT)
	check_hostname
	changes="no"
	if [ -n "$old_ip_address" ]; then
		if [ -n "$alias_ip_address" ] && \
		   [ "$old_ip_address" != "$alias_ip_address" ]; then
			delete_old_alias
			changes="yes"
		fi
		if [ "$old_ip_address" != "$new_ip_address" ]; then
			delete_old_address
			delete_old_routes
			changes="yes"
		fi
	fi
	if [ "$reason" = BOUND ] || \
	   [ "$reason" = REBOOT ] || \
	   [ -z "$old_ip_address" ] || \
	   [ "$old_ip_address" != "$new_ip_address" ]; then
		add_new_address
		add_new_routes
		changes="yes"
	fi
	if [ -n "$alias_ip_address" ] && \
       [ "$new_ip_address" != "$alias_ip_address" ]; then
		add_new_alias
		changes="yes"
	fi
	add_new_resolv_conf
	if [ "$changes" = "yes" ] ; then
		notify_rc_newwanip
	fi
	;;

EXPIRE|FAIL|RELEASE)
	delete_old_alias
	if [ -n "$old_ip_address" ]; then
		delete_old_address
		delete_old_routes
	fi
	;;

TIMEOUT)
	# This case must exit zero only if the cached address
	# is considered valid. See dhclient-script(8).
	exit_status=1
	delete_old_alias
	add_new_address
	/bin/sleep 1
	if [ -n "$new_routers" ]; then
		_logger "LOG_NOTICE" "New Routers (${interface}): ${new_routers}"
		set "$new_routers"
		if /sbin/ping -q -c 1 -t 1 "$1"; then
			if [ "$new_ip_address" != "$alias_ip_address" ]; then
				add_new_alias
			fi
			add_new_routes
			if add_new_resolv_conf; then
				notify_rc_newwanip
			fi
			exit_status=0
		fi
	fi
	if [ "$exit_status" -ne 0 ]; then
		eval "$IFCONFIG" "$interface" inet -alias "$new_ip_address" "$medium"
		delete_old_routes
	fi
	;;
esac

# Invoke the local dhcp client exit hooks, if they exist.
if [ -f /etc/dhclient-exit-hooks ]; then
	_logger "LOG_NOTICE" "dhclient-exit-hooks"
	. /etc/dhclient-exit-hooks
	# allow the local script to abort processing of this state
	# local script must set exit_status variable to nonzero.
fi
exit $exit_status
