#!/bin/sh
# Script to set up one of the nodes as a NAT gateway for all other nodes.
# This is used to ensure that all nodes in the cluster can still originate
# traffic to the external network even if there are no public addresses
# available.
#

. $CTDB_BASE/functions
loadconfig

[ -z "$CTDB_NATGW_PUBLIC_IFACE" ] && exit 0

delete_all() {
	local _ip=`echo $CTDB_NATGW_PUBLIC_IP | cut -d '/' -f1`
	local _maskbits=`echo $CTDB_NATGW_PUBLIC_IP | cut -d '/' -f2`

	delete_ip_from_iface $CTDB_NATGW_PUBLIC_IFACE $_ip $_maskbits
	delete_ip_from_iface lo $_ip 32

	ip route del 0.0.0.0/0 metric 10 >/dev/null 2>/dev/null

	# Delete the masquerading setup from a previous iteration where we
	# were the NAT-GW
	iptables -D POSTROUTING -t nat -s $CTDB_NATGW_PRIVATE_NETWORK -d ! $CTDB_NATGW_PRIVATE_NETWORK -j MASQUERADE >/dev/null 2>/dev/null

}

case "$1" in 
    startup)
	# do not respond to ARPs that are for ip addresses with scope 'host'
	echo 3 > /proc/sys/net/ipv4/conf/all/arp_ignore
	# do not send out arp requests from loopback addresses
	echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce
	# update capabilities to show we are using natgw
	ctdb setnatgwstate on
	;;

    recovered|updatenatgw)
	MYPNN=`ctdb pnn | cut -d: -f2`
	NATGWMASTER=`ctdb natgwlist | head -1 | sed -e "s/ .*//"`
	NATGWIP=`ctdb natgwlist | head -1 | sed -e "s/^[^ ]* *//"`

	CTDB_NATGW_PUBLIC_IP_HOST=`echo $CTDB_NATGW_PUBLIC_IP | sed -e "s/\/.*/\/32/"`
	if [ "$NATGWMASTER" = "-1" ]; then
		echo "There is not NATGW master node"
		exit 1
	fi

	delete_all

	if [ "$MYPNN" = "$NATGWMASTER" ]; then
		# This is the first node, set it up as the NAT GW
		echo 1 >/proc/sys/net/ipv4/ip_forward
		iptables -A POSTROUTING -t nat -s $CTDB_NATGW_PRIVATE_NETWORK -d ! $CTDB_NATGW_PRIVATE_NETWORK -j MASQUERADE
		ip addr add $CTDB_NATGW_PUBLIC_IP dev $CTDB_NATGW_PUBLIC_IFACE
		ip route add 0.0.0.0/0 via $CTDB_NATGW_DEFAULT_GATEWAY >/dev/null 2>/dev/null
	else
		# This is not the NAT-GW
		# Assign the public ip to the private interface and make
		# sure we dont respond to ARPs.
		# We do this so that the ip address will exist on a
		# non-loopback interface so that samba may send it along in the
		# KDC requests.
		ip addr add $CTDB_NATGW_PUBLIC_IP_HOST dev lo scope host
		ip route add 0.0.0.0/0 via $NATGWIP metric 10
	fi

	# flush our route cache
	echo 1 > /proc/sys/net/ipv4/route/flush
	;;

    shutdown|stopped|removenatgw)
	delete_all
	;;

    *)
	ctdb_standard_event_handler "@"
	;;
esac

exit 0