#!/bin/sh

#################################
# interface event script for ctdb
# this adds/removes IPs from your 
# public interface

[ -n "$CTDB_BASE" ] || \
    export CTDB_BASE=$(cd -P $(dirname "$0") ; dirname "$PWD")

. $CTDB_BASE/functions
loadconfig

[ -z "$CTDB_PUBLIC_ADDRESSES" ] && {
	CTDB_PUBLIC_ADDRESSES=$CTDB_BASE/public_addresses
}

[ ! -f "$CTDB_PUBLIC_ADDRESSES" ] && {
	if [ "$1" = "init" ]; then
		echo "No public addresses file found. Nothing to do for 10.interfaces"
	fi
	exit 0
}

mark_up ()
{
    up_interfaces_found=true
    ctdb setifacelink $1 up >/dev/null 2>&1
}

mark_down ()
{
    fail=true
    ctdb setifacelink $1 down >/dev/null 2>&1
}

# This sets $all_interfaces as a side-effect.
get_all_interfaces ()
{
    # Get all the interfaces listed in the public_addresses file
    all_interfaces=$(sed -e "s/^[^\t ]*[\t ]*//" -e "s/,/ /g" -e "s/[\t ]*$//" $CTDB_PUBLIC_ADDRESSES)

    # Add some special interfaces if they're defined
    [ "$CTDB_PUBLIC_INTERFACE" ] && all_interfaces="$CTDB_PUBLIC_INTERFACE $all_interfaces"
    [ "$CTDB_NATGW_PUBLIC_IFACE" ] && all_interfaces="$CTDB_NATGW_PUBLIC_IFACE $all_interfaces"

    # Get the interfaces for which CTDB has public IPs configured.
    # That is, for all but the 1st line, get the 1st field.
    ctdb_ifaces=$(ctdb -Y ifaces | sed -e '1d' -e 's@^:@@' -e 's@:.*@@')

    # Add $ctdb_interfaces and uniquify
    all_interfaces=$(echo $all_interfaces $ctdb_ifaces | tr ' ' '\n' | sort -u)
}

monitor_interfaces()
{
	get_all_interfaces

	fail=false
	up_interfaces_found=false

	# Note that this loop must not exit early.  It must process
	# all interfaces so that the correct state for each interface
	# is set in CTDB using mark_up/mark_down.  If there is a
	# problem with an interface then set fail=true and continue.
	for iface in $all_interfaces ; do

	    ip link show $iface 2>/dev/null >/dev/null || {
		echo "ERROR: Interface $iface does not exist but it is used by public addresses."
		mark_down $iface
		continue
	    }

	    # These interfaces are sometimes bond devices
	    # When we use VLANs for bond interfaces, there will only
	    # be an entry in /proc for the underlying real interface
	    realiface=`echo $iface |sed -e 's/\..*$//'`
	    bi=$(get_proc "net/bonding/$realiface" 2>/dev/null) && {
		echo "$bi" | grep -q 'Currently Active Slave: None' && {
			echo "ERROR: No active slaves for bond device $realiface"
			mark_down $iface
			continue
		}
		echo "$bi" | grep -q '^MII Status: up' || {
			echo "ERROR: public network interface $realiface is down"
			mark_down $iface
			continue
		}
		echo "$bi" | grep -q '^Bonding Mode: IEEE 802.3ad Dynamic link aggregation' && {
			# This works around a bug in the driver where the
			# overall bond status can be up but none of the actual
			# physical interfaces have a link.
			echo "$bi" | grep 'MII Status:' | tail -n +2 | grep -q '^MII Status: up' || {
				echo "ERROR: No active slaves for 802.ad bond device $realiface"
				mark_down $iface
				continue
			}
		}
		mark_up $iface
		continue
	    }

	    case $iface in
	    lo*)
		# loopback is always working
		mark_up $iface
		;;
	    ib*)
		# we dont know how to test ib links
		mark_up $iface
		;;
	    *)
		[ -z "$iface" ] || {
		    [ "$(basename $(readlink /sys/class/net/$iface/device/driver) 2>/dev/null)" = virtio_net ] ||
		    ethtool $iface | grep -q 'Link detected: yes' || {
			# On some systems, this is not successful when a
			# cable is plugged but the interface has not been
			# brought up previously. Bring the interface up and
			# try again...
			ip link set $iface up
			ethtool $iface | grep -q 'Link detected: yes' || {
			    echo "ERROR: No link on the public network interface $iface"
			    mark_down $iface
			    continue
			}
		    }
		    mark_up $iface
		}
		;;
	    esac

	done

	$fail || return 0

	$up_interfaces_found && \
	    [ "$CTDB_PARTIALLY_ONLINE_INTERFACES" = "yes" ] && \
	    return 0

	return 1
}

ctdb_check_args "$@"

case "$1" in 
     #############################
     # called when ctdbd starts up
     init)
	# make sure that we only respond to ARP messages from the NIC where
	# a particular ip address is associated.
	get_proc sys/net/ipv4/conf/all/arp_filter >/dev/null 2>&1 && {
	    set_proc sys/net/ipv4/conf/all/arp_filter 1
	}
	;;

     #############################
     # called after ctdbd has done its initial recovery
     # and we start the services to become healthy
     startup)
	monitor_interfaces
	;;


     ################################################
     # called when ctdbd wants to claim an IP address
     takeip)
	iface=$2
	ip=$3
	maskbits=$4

	add_ip_to_iface $iface $ip $maskbits || {
		exit 1;
	}

	# cope with the script being killed while we have the interface blocked
	iptables -D INPUT -i $iface -d $ip -j DROP 2> /dev/null

	# flush our route cache
	set_proc sys/net/ipv4/route/flush 1
	;;


     ##################################################
     # called when ctdbd wants to release an IP address
     releaseip)
	# releasing an IP is a bit more complex than it seems. Once the IP
	# is released, any open tcp connections to that IP on this host will end
	# up being stuck. Some of them (such as NFS connections) will be unkillable
	# so we need to use the killtcp ctdb function to kill them off. We also
	# need to make sure that no new connections get established while we are 
	# doing this! So what we do is this:
	# 1) firewall this IP, so no new external packets arrive for it
	# 2) use netstat -tn to find existing connections, and kill them 
	# 3) remove the IP from the interface
	# 4) remove the firewall rule
	iface=$2
	ip=$3
	maskbits=$4

	failed=0
	# we do an extra delete to cope with the script being killed
	iptables -D INPUT -i $iface -d $ip -j DROP 2> /dev/null
	iptables -I INPUT -i $iface -d $ip -j DROP
	kill_tcp_connections $ip

	delete_ip_from_iface $iface $ip $maskbits || {
		iptables -D INPUT -i $iface -d $ip -j DROP 2> /dev/null
		exit 1;
	}

	iptables -D INPUT -i $iface -d $ip -j DROP 2> /dev/null

	# flush our route cache
	set_proc sys/net/ipv4/route/flush 1
	;;

     ##################################################
     # called when ctdbd wants to update an IP address
     updateip)
	# moving an IP is a bit more complex than it seems.
	# First we drop all traffic on the old interface.
	# Then we try to add the ip to the new interface and before
	# we finally remove it from the old interface.
	#
	# 1) firewall this IP, so no new external packets arrive for it
	# 2) add the IP to the new interface
	# 3) remove the IP from the old interface
	# 4) remove the firewall rule
	# 5) use ctdb gratiousarp to propagate the new mac address
	# 6) use netstat -tn to find existing connections, and tickle them
	oiface=$2
	niface=$3
	ip=$4
	maskbits=$5

	failed=0
	# we do an extra delete to cope with the script being killed
	iptables -D INPUT -i $oiface -d $ip -j DROP 2> /dev/null
	iptables -I INPUT -i $oiface -d $ip -j DROP

	delete_ip_from_iface $oiface $ip $maskbits 2>/dev/null
	delete_ip_from_iface $niface $ip $maskbits 2>/dev/null

	add_ip_to_iface $niface $ip $maskbits || {
		iptables -D INPUT -i $oiface -d $ip -j DROP 2> /dev/null
		exit 1;
	}

	# cope with the script being killed while we have the interface blocked
	iptables -D INPUT -i $oiface -d $ip -j DROP 2> /dev/null

	# flush our route cache
	set_proc sys/net/ipv4/route/flush 1

	# propagate the new mac address
	ctdb gratiousarp $ip $niface

	# tickle all existing connections, so that dropped packets
	# are retransmited and the tcp streams work

	tickle_tcp_connections $ip

	;;

     monitor)
	monitor_interfaces || exit 1
	;;
    *)
	ctdb_standard_event_handler "$@"
	;;
esac

exit 0

