samba-mirror/ctdb/config/events/legacy/10.interface.script

#!/bin/sh

# Handle public IP address release and takeover, as well as monitoring
# interfaces used by public IP addresses.

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

. "${CTDB_BASE}/functions"

load_script_options

if ! have_public_addresses; then
	if [ "$1" = "init" ] ; then
		echo "No public addresses file found"
	fi
	exit 0
fi

monitor_interfaces()
{
	get_public_ifaces

	down_interfaces_found=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 setifacelink.
	#
	# public_ifaces set by get_public_ifaces() above
	# shellcheck disable=SC2154
	for _iface in $public_ifaces ; do
		if interface_monitor "$_iface" ; then
			up_interfaces_found=true
			$CTDB setifacelink "$_iface" up >/dev/null 2>&1
		else
			down_interfaces_found=true
			$CTDB setifacelink "$_iface" down >/dev/null 2>&1
		fi
	done

	if ! $down_interfaces_found ; then
		return 0
	fi

	if ! $up_interfaces_found ; then
		return 1
	fi

	if [ "$CTDB_PARTIALLY_ONLINE_INTERFACES" != "yes" ]; then
		return 1
	fi

	return 0
}

# Sets: iface, ip, maskbits
get_iface_ip_maskbits ()
{
    _iface_in="$1"
    ip="$2"
    _maskbits_in="$3"

    # Intentional word splitting here
    # shellcheck disable=SC2046
    set -- $(ip_maskbits_iface "$ip")
    if [ -n "$1" ] ; then
	maskbits="$1"
	iface="$2"

	if [ "$iface" != "$_iface_in" ] ; then
	    printf \
		'WARNING: Public IP %s hosted on interface %s but VNN says %s\n' \
		"$ip" "$iface" "$_iface_in"
	fi
	if [ "$maskbits" != "$_maskbits_in" ] ; then
	    printf \
		'WARNING: Public IP %s has %s bit netmask but VNN says %s\n' \
		    "$ip" "$maskbits" "$_maskbits_in"
	fi
    else
	die "ERROR: Unable to determine interface for IP ${ip}"
    fi
}

ip_block ()
{
	_ip="$1"
	_iface="$2"

	case "$_ip" in
	*:*) _family="inet6" ;;
	*)   _family="inet"  ;;
	esac

	# Extra delete copes with previously killed script
	iptables_wrapper "$_family" \
			 -D INPUT -i "$_iface" -d "$_ip" -j DROP 2>/dev/null
	iptables_wrapper "$_family" \
			 -I INPUT -i "$_iface" -d "$_ip" -j DROP
}

ip_unblock ()
{
	_ip="$1"
	_iface="$2"

	case "$_ip" in
	*:*) _family="inet6" ;;
	*)   _family="inet"  ;;
	esac

	iptables_wrapper "$_family" \
			 -D INPUT -i "$_iface" -d "$_ip" -j DROP 2>/dev/null
}

ctdb_check_args "$@"

case "$1" in
init)
	_promote="sys/net/ipv4/conf/all/promote_secondaries"
	get_proc "$_promote" >/dev/null 2>&1 || \
	    die "Public IPs only supported if promote_secondaries is available"

	# Make sure we drop any IPs that might still be held if
	# previous instance of ctdbd got killed with -9 or similar
	drop_all_public_ips
	;;

startup)
	monitor_interfaces
	;;

shutdown)
	drop_all_public_ips
	;;

takeip)
	iface=$2
	ip=$3
	maskbits=$4

	update_my_public_ip_addresses "takeip" "$ip"

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

	# In case a previous "releaseip" for this IP was killed...
	ip_unblock "$ip" "$iface"

	flush_route_cache
	;;

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 terminate
	# them. We also need to make sure that no new connections get
	# established while we are doing this.
	#
	# The steps are:
	#
	# 1) firewall this IP, so no new external packets arrive for it
	# 2) find existing connections, and kill them
	# 3) remove the IP from the interface
	# 4) remove the firewall rule
	shift
	get_iface_ip_maskbits "$@"

	ip_block "$ip" "$iface"

	kill_tcp_connections "$iface" "$ip"

	update_my_public_ip_addresses "releaseip" "$ip"

	delete_ip_from_iface "$iface" "$ip" "$maskbits" || {
		ip_unblock "$ip" "$iface"
		exit 1
	}

	ip_unblock "$ip" "$iface"

	flush_route_cache
	;;

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
	# remove the IP from the old interface and add it to the new
	# interface.
	#
	# The steps are:
	#
	# 1) firewall this IP, so no new external packets arrive for it
	# 2) remove the IP from the old interface (and new interface, to be sure)
	# 3) add the IP to the new interface
	# 4) remove the firewall rule
	# 5) use ctdb gratarp to propagate the new mac address
	# 6) send tickle ACKs for existing connections, so dropped
	#    packets are resent
	_oiface=$2
	niface=$3
	_ip=$4
	_maskbits=$5

	get_iface_ip_maskbits "$_oiface" "$_ip" "$_maskbits"
	oiface="$iface"

	# Could check maskbits too.  However, that should never change
	# so we want to notice if it does.
	if [ "$oiface" = "$niface" ] ; then
		echo "Redundant \"updateip\" - ${ip} already on ${niface}"
		exit 0
	fi

	ip_block "$ip" "$oiface"

	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" "$maskbits" || {
		ip_unblock "$ip" "$oiface"
		exit 1
	}

	ip_unblock "$ip" "$oiface"

	flush_route_cache

	# Propagate the new MAC address
	$CTDB gratarp "$ip" "$niface"

	# Tickle all existing connections, so that dropped packets
	# are retransmitted and the tcp streams work
	tickle_tcp_connections "$ip"
	;;

ipreallocated)
	# Just to make sure
	update_my_public_ip_addresses "ipreallocated"
	;;

monitor)
	monitor_interfaces || exit 1
	;;
esac

exit 0