dhclient-script

#!/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.
#

NETSTAT=/usr/bin/netstat
GREP=/usr/bin/grep
AWK=/usr/bin/awk
HOSTNAME=/bin/hostname
GREP=/usr/bin/grep
ROUTE=/sbin/route
SED=/usr/bin/sed
ARP=/usr/sbin/arp
IFCONFIG=/sbin/ifconfig

LOCALHOST=127.0.0.1

if [ -x /usr/bin/logger ]; then
	LOGGER="/usr/bin/logger -s -p user.notice -t dhclient"
else
	LOGGER=echo
fi

#
# Helper functions that implement common actions.
#

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

arp_flush() {
	$ARP -an -i $interface | \
		$SED -n -e 's/^.*(\(.*\)) at .*$/arp -d \1/p' | \
		/bin/sh >/dev/null 2>&1
}

delete_old_states() {
	$LOGGER "Starting delete_old_states()"
	# If the IP changed, remove states from the old one
	if [ -f /var/db/${interface}_ip ]; then
		OLD_IP = `cat /var/db/${interface}_ip`
		$LOGGER "Comparing IPs: Old: ${OLD_IP} New: ${new_ip_address}"
		if [ -n "${OLD_IP}" ] && [ "${OLD_IP}" != "${new_ip_address}" ]; then
			$LOGGER "Removing states from old IP '${OLD_IP}' (new IP '${new_ip_address}')"
			/sbin/pfctl -i $interface -Fs
			pfctl -K ${OLD_IP}/32
		fi
	fi
	# Delete states through old gateway if it's not the same
	if [ -n "${old_routers}" ]; then
		OLD_ROUTER = $old_routers
	fi
	if [ -z "${OLD_ROUTER}" ] && [ -f /tmp/${interface}_router ]; then
		OLD_ROUTER = `cat /tmp/${interface}_router`
	fi
	if [ -n "${OLD_ROUTER}" ]; then
		$LOGGER "Comparing Routers: Old: ${OLD_ROUTER} New: ${new_routers}"
		if [ "${OLD_ROUTER}" != "${new_routers}" ]; then
			$LOGGER "Removing states through old gateway '${OLD_ROUTER}' (new gateway '${new_routers}')"
			/sbin/pfctl -i $interface -Fs -G ${OLD_ROUTER}
		fi
	fi
}

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

add_new_address() {

	$LOGGER "Starting add_new_address()"

	$LOGGER "ifconfig $interface inet $new_ip_address netmask $new_subnet_mask broadcast $new_broadcast_address $medium"

	$IFCONFIG $interface \
		inet $new_ip_address \
		netmask $new_subnet_mask \
		broadcast $new_broadcast_address \
		$medium
	$IFCONFIG $interface setfirst $new_ip_address

	$LOGGER "New IP Address ($interface): $new_ip_address"
	$LOGGER "New Subnet Mask ($interface): $new_subnet_mask"
	$LOGGER "New Broadcast Address ($interface): $new_broadcast_address"
	$LOGGER "New Routers ($interface): $new_routers"


	# This is necessary otherwise apinger will try to ping all 1s address
	if [ -n "$new_routers" ] && [ "$new_routers" != "255.255.255.255" ]; then
		echo $new_routers > /tmp/${interface}_router
	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 "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
			$ROUTE delete default $router >/dev/null 2>&1
			/bin/rm -f /tmp/${interface}_router
		done
	fi

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

	arp_flush
}

add_new_routes() {
	$LOGGER "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"
		$LOGGER "New Classless Static Routes ($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
	EXISTSGW=`/bin/ls -l /tmp/*_defaultgw | /usr/bin/wc -l`
	# Only allow the default route to be overridden if it's on our own interface
	if [ -f "/tmp/${interface}_defaultgw" -o $EXISTSGW -eq 0 ]; then
		$ROUTE delete default
		for router in $new_routers; do
			if [ "$new_ip_address" = "$router" -o "$router" = "255.255.255.255" ]; then
				$ROUTE add default -iface $interface
				echo $ROUTE add default -iface $interface | $LOGGER
				# NOTE: Do not activate this for all ones address since pf(4) will try to forward packets to it.
				if [ "$new_ip_address" = "$router" ]; then
					echo $router > /tmp/${interface}_router
				fi
			else
				$ROUTE add default $router
				echo $ROUTE add default $router | $LOGGER
                       		echo $router > /tmp/${interface}_router
			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
		$LOGGER "New Static Routes ($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
			fi
			shift; shift
		done
	fi
}

add_new_resolv_conf() {
	$LOGGER "Creating resolv.conf"
	if [ -f "/var/etc/nameserver_$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/bin/grep dnsallowoverride /conf/config.xml | /usr/bin/wc -l`
		for nameserver in $new_domain_name_servers; do
			# Add a route to the nameserver out the correct interface
			# so that mulitple wans work correctly with multiple dns
			# also backup the nameserver for later route removal
			if [ $ALLOWOVERRIDE -gt 0 ]; 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.
#

# Invoke the local dhcp client enter hooks, if they exist.
if [ -f /etc/dhclient-enter-hooks ]; then
	$LOGGER "dhclient-enter-hooks"
	exit_status=0
	. /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

#if [ -x $ROUTE ]; then
#	if_defaultroute=`$ROUTE -n get -inet default | $GREP interface | $AWK '{print $2}'`
#else
#	$LOGGER "if_defaultroute"
#	if_defaultroute="x"
#fi

$LOGGER $reason
case $reason in
MEDIUM)
	$IFCONFIG $interface $medium
	$IFCONFIG $interface inet -alias 0.0.0.0 $medium >/dev/null 2>&1
	/bin/sleep 1
	;;

PREINIT)
	delete_old_alias
	$IFCONFIG $interface inet 0.0.0.0 netmask 0.0.0.0 broadcast 255.255.255.255 up
	delete_old_states
	/bin/rm -f /tmp/${interface}_router
	;;

ARPCHECK|ARPSEND)
	;;

BOUND|RENEW|REBIND|REBOOT)
	check_hostname
	changes="no"
	if [ "$old_ip_address" != "$new_ip_address" ]; then
		delete_old_states
	fi
	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)
	delete_old_alias
	delete_old_states
	if [ -n "$old_ip_address" ]; then
		delete_old_address
		delete_old_routes
	fi
	;;

TIMEOUT)
	delete_old_alias
	add_new_address
	/bin/sleep 1
	if [ -n "$new_routers" ]; then
		$LOGGER "New Routers ($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
		fi
	fi
	$IFCONFIG $interface inet -alias $new_ip_address $medium
	delete_old_states
	delete_old_routes
	;;
esac

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