#!/bin/sh
#
#	   OCF Resource Agent compliant script.
#	   Monitor the vitality of a local network interface.
#
# 	Based on the work by Robert Euhus and Lars Marowsky-Bree.
#
#	Transfered from Ipaddr2 into ethmonitor by Alexander Krauth
#
# Copyright (c) 2011 Robert Euhus, Alexander Krauth, Lars Marowsky-Brée
#					All Rights Reserved.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of version 2 of the GNU General Public License as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it would be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
#
# Further, this software is distributed without any warranty that it is
# free of the rightful claim of any third person regarding infringement
# or the like.  Any license provided herein, whether implied or
# otherwise, applies only to this software file.  Patent licenses, if
# any, provided herein do not apply to combinations of this program with
# other software, or any other product whatsoever.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write the Free Software Foundation,
# Inc., 59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
#
#	 OCF parameters are as below
#
#	OCF_RESKEY_interface
#	OCF_RESKEY_multiplicator
#	OCF_RESKEY_name
#	   OCF_RESKEY_repeat_count
#	OCF_RESKEY_repeat_interval
#	OCF_RESKEY_pktcnt_timeout
#	OCF_RESKEY_arping_count
#	OCF_RESKEY_arping_timeout
#	OCF_RESKEY_arping_cache_entries
#
#   TODO: Check against IPv6
#
#######################################################################
# Initialization:

: ${OCF_FUNCTIONS_DIR=${OCF_ROOT}/lib/heartbeat}
. ${OCF_FUNCTIONS_DIR}/ocf-shellfuncs

# Parameter defaults

OCF_RESKEY_interface_default=""
OCF_RESKEY_name_default=""
OCF_RESKEY_multiplier_default="1"
OCF_RESKEY_repeat_count_default="5"
OCF_RESKEY_repeat_interval_default="10"
OCF_RESKEY_pktcnt_timeout_default="5"
OCF_RESKEY_arping_count_default="1"
OCF_RESKEY_arping_timeout_default="1"
OCF_RESKEY_arping_cache_entries_default="5"
OCF_RESKEY_link_status_only_default="false"

: ${OCF_RESKEY_interface=${OCF_RESKEY_interface_default}}
: ${OCF_RESKEY_name=${OCF_RESKEY_name_default}}
: ${OCF_RESKEY_multiplier=${OCF_RESKEY_multiplier_default}}
: ${OCF_RESKEY_repeat_count=${OCF_RESKEY_repeat_count_default}}
: ${OCF_RESKEY_repeat_interval=${OCF_RESKEY_repeat_interval_default}}
: ${OCF_RESKEY_pktcnt_timeout=${OCF_RESKEY_pktcnt_timeout_default}}
: ${OCF_RESKEY_arping_count=${OCF_RESKEY_arping_count_default}}
: ${OCF_RESKEY_arping_timeout=${OCF_RESKEY_arping_timeout_default}}
: ${OCF_RESKEY_arping_cache_entries=${OCF_RESKEY_arping_cache_entries_default}}
: ${OCF_RESKEY_link_status_only=${OCF_RESKEY_link_status_only_default}}

#######################################################################

meta_data() {
	cat <<END
<?xml version="1.0"?>
<!DOCTYPE resource-agent SYSTEM "ra-api-1.dtd">
<resource-agent name="ethmonitor" version="1.2">
<version>1.0</version>

<longdesc lang="en">
Monitor the vitality of a local network interface.

You may set up this RA as a clone resource to monitor the network interfaces on different nodes, with the same interface name.
This is not related to the IP address or the network on which a interface is configured.
You may use this RA to move resources away from a node, which has a faulty interface or prevent moving resources to such a node.
This gives you independent control of the resources, without involving cluster intercommunication. But it requires your nodes to have more than one network interface.

The resource configuration requires a monitor operation, because the monitor does the main part of the work.
In addition to the resource configuration, you need to configure some location constraints, based on a CIB attribute value.
The name of the attribute value is configured in the 'name' option of this RA.

Example constraint configuration using crmsh
location loc_connected_node my_resource_grp \
        rule $id="rule_loc_connected_node" -INF: ethmonitor eq 0

Example constraint configuration using pcs. Only allow 'my_resource' to run on nodes where eth0 ethernet device is available.
pcs constraint location my_resource rule score=-INFINITY ethmonitor-eth0 ne 1

The ethmonitor works in 3 different modes to test the interface vitality.
1. call ip to see if the link status is up (if link is down -> error)
2. call ip and watch the RX counter (if packages come around in a certain time -> success)
3. call arping to check whether any of the IPs found in the local ARP cache answers an ARP REQUEST (one answer -> success)
4. return error
</longdesc>
<shortdesc lang="en">Monitors network interfaces</shortdesc>

<parameters>
<parameter name="interface" unique="1" required="1">
<longdesc lang="en">
The name of the network interface which should be monitored (e.g. eth0).
</longdesc>
<shortdesc lang="en">Network interface name</shortdesc>
<content type="string" default="${OCF_RESKEY_interface_default}"/>
</parameter>

<parameter name="name" unique="1">
<longdesc lang="en">
The name of the CIB attribute to set.  This is the name to be used in the constraints. Defaults to "ethmonitor-'interface_name'".
</longdesc>
<shortdesc lang="en">Attribute name</shortdesc>
<content type="string" default="${OCF_RESKEY_name_default}"/>
</parameter>

<parameter name="multiplier" unique="0" >
<longdesc lang="en">
Multiplier for the value of the CIB attriobute specified in parameter name. 
</longdesc>
<shortdesc lang="en">Multiplier for result variable</shortdesc>
<content type="integer" default="${OCF_RESKEY_multiplier_default}"/>
</parameter>

<parameter name="repeat_count">
<longdesc lang="en">
Specify how often the interface will be monitored, before the status is set to failed. You need to set the timeout of the monitoring operation to at least repeat_count * repeat_interval
</longdesc>
<shortdesc lang="en">Monitor repeat count</shortdesc>
<content type="integer" default="${OCF_RESKEY_repeat_count_default}"/>
</parameter>

<parameter name="repeat_interval">
<longdesc lang="en">
Specify how long to wait in seconds between the repeat_counts.
</longdesc>
<shortdesc lang="en">Monitor repeat interval in seconds</shortdesc>
<content type="integer" default="${OCF_RESKEY_repeat_interval_default}"/>
</parameter>

<parameter name="pktcnt_timeout">
<longdesc lang="en">
Timeout for the RX packet counter. Stop listening for packet counter changes after the given number of seconds.
</longdesc>
<shortdesc lang="en">packet counter timeout</shortdesc>
<content type="integer" default="${OCF_RESKEY_pktcnt_timeout_default}"/>
</parameter>

<parameter name="arping_count">
<longdesc lang="en">
Number of ARP REQUEST packets to send for every IP.
Usually one ARP REQUEST (arping) is send
</longdesc>
<shortdesc lang="en">Number of arpings per IP</shortdesc>
<content type="integer" default="${OCF_RESKEY_arping_count_default}"/>
</parameter>

<parameter name="arping_timeout">
<longdesc lang="en">
Time in seconds to wait for ARP REQUESTs (all packets of arping_count).
This is to limit the time for arp requests, to be able to send requests to more than one node, without running in the monitor operation timeout.
</longdesc>
<shortdesc lang="en">Timeout for arpings per IP</shortdesc>
<content type="integer" default="${OCF_RESKEY_arping_timeout_default}"/>
</parameter>

<parameter name="arping_cache_entries">
<longdesc lang="en">
Maximum number of IPs from ARP cache list to check for ARP REQUEST (arping) answers. Newest entries are tried first.
</longdesc>
<shortdesc lang="en">Number of ARP cache entries to try</shortdesc>
<content type="integer" default="${OCF_RESKEY_arping_cache_entries_default}"/>
</parameter>

<parameter name="infiniband_device">
<longdesc lang="en">
For interfaces that are infiniband devices.
</longdesc>
<shortdesc lang="en">infiniband device</shortdesc>
<content type="string" />
</parameter>

<parameter name="infiniband_port">
<longdesc lang="en">
For infiniband devices, this is the port to monitor.
</longdesc>
<shortdesc lang="en">infiniband port</shortdesc>
<content type="integer" />
</parameter>

<parameter name="link_status_only">
<longdesc lang="en">
Only report success based on link status. Do not perform RX counter or arping related connectivity tests.
</longdesc>
<shortdesc lang="en">link status check only</shortdesc>
<content type="boolean" default="${OCF_RESKEY_link_status_only_default}" />
</parameter>

</parameters>
<actions>
<action name="start" timeout="60s" />
<action name="stop" timeout="20s" />
<action name="status" depth="0" timeout="60s" interval="10s" />
<action name="monitor" depth="0" timeout="60s" interval="10s" />
<action name="meta-data" timeout="5s" />
<action name="validate-all" timeout="20s" />
</actions>
</resource-agent>
END

	exit $OCF_SUCCESS
}

#
# Return true, if the interface exists
#
is_interface() {
	#
	# List interfaces but exclude FreeS/WAN ipsecN virtual interfaces
	#
	local iface=`$IP2UTIL -o -f link addr show | grep -e " $1[:@]" \
		| cut -d ' ' -f2 | tr -d ':' | cut -d '@' -f1 | sort -u | grep -v '^ipsec[0-9][0-9]*$'`
		[ "$iface" != "" ]
}

infiniband_status()
{
	local device="$OCF_RESKEY_infiniband_device"

	if [ -n "$OCF_RESKEY_infiniband_port" ]; then
		device="${OCF_RESKEY_infiniband_device}:${OCF_RESKEY_infiniband_port}"
	fi
	
	case "${OCF_RESKEY_infiniband_device}" in
		*ib*|*mlx*) ibstatus ${device} | grep -q ACTIVE ;;
		*hfi*) opainfo | grep -q Active ;;
	esac
}

if_init() {
	local rc

	if [ X"$OCF_RESKEY_interface" = "X" ]; then
		ocf_exit_reason "Interface name (the interface parameter) is mandatory"
		exit $OCF_ERR_CONFIGURED
	fi

	NIC="$OCF_RESKEY_interface"

	if is_interface $NIC
	then
		case "$NIC" in
			*:*) ocf_exit_reason "Do not specify a virtual interface : $OCF_RESKEY_interface"
				 exit $OCF_ERR_CONFIGURED;;
			*)   ;;
		esac
	else
		case $__OCF_ACTION in
			validate-all)
				ocf_exit_reason "Interface $NIC does not exist"
				exit $OCF_ERR_CONFIGURED;;
			monitor)
				ocf_log debug "Interface $NIC does not exist"
				;;
			*)	
				## It might be a bond interface which is temporarily not available, therefore we want to continue here
				ocf_log warn "Interface $NIC does not exist"
				;;
		esac
	fi

	if ! ocf_is_decimal "$OCF_RESKEY_multiplier"; then
		ocf_exit_reason "Invalid OCF_RESKEY_multiplier [$OCF_RESKEY_multiplier]"
		exit $OCF_ERR_CONFIGURED
	fi
	
	ATTRNAME=${OCF_RESKEY_name:-"ethmonitor-$NIC"}
	
	REP_COUNT=${OCF_RESKEY_repeat_count:-5}
	if ! ocf_is_decimal "$REP_COUNT" -o [ $REP_COUNT -lt 1 ]; then
		ocf_exit_reason "Invalid OCF_RESKEY_repeat_count [$REP_COUNT]"
		exit $OCF_ERR_CONFIGURED
	fi
	REP_INTERVAL_S=${OCF_RESKEY_repeat_interval:-10}
	if ! ocf_is_decimal "$REP_INTERVAL_S"; then
		ocf_exit_reason "Invalid OCF_RESKEY_repeat_interval [$REP_INTERVAL_S]"
		exit $OCF_ERR_CONFIGURED
	fi
	if ! ocf_is_decimal "$OCF_RESKEY_pktcnt_timeout"; then
		ocf_exit_reason "Invalid OCF_RESKEY_pktcnt_timeout [$OCF_RESKEY_pktcnt_timeout]"
		exit $OCF_ERR_CONFIGURED
	fi
	if ! ocf_is_decimal "$OCF_RESKEY_arping_count"; then
		ocf_exit_reason "Invalid OCF_RESKEY_arping_count [$OCF_RESKEY_arping_count]"
		exit $OCF_ERR_CONFIGURED
	fi
	if ! ocf_is_decimal "$OCF_RESKEY_arping_timeout"; then
		ocf_exit_reason "Invalid OCF_RESKEY_arping_timeout [$OCF_RESKEY_arping_count]"
		exit $OCF_ERR_CONFIGURED
	fi
	if ! ocf_is_decimal "$OCF_RESKEY_arping_cache_entries"; then
		ocf_exit_reason "Invalid OCF_RESKEY_arping_cache_entries [$OCF_RESKEY_arping_cache_entries]"
		exit $OCF_ERR_CONFIGURED
	fi

	if [ -n "$OCF_RESKEY_infiniband_device" ]; then
		#ibstatus or opainfo is required if an infiniband_device is provided
		case "${OCF_RESKEY_infiniband_device}" in
			*ib*|*mlx*) check_binary ibstatus ;;
			*hfi*) check_binary opainfo ;;
		esac
	fi
	return $OCF_SUCCESS
}

# get the link status on $NIC
# asks ip about running (up) interfaces, returns the number of matching interface names that are up
get_link_status () {
	$IP2UTIL -o link show up dev "$NIC" | grep -v 'NO-CARRIER' | grep -c "$NIC"
}

# returns the number of received rx packets on $NIC
get_rx_packets () {
	ocf_log debug "$IP2UTIL -o -s link show dev $NIC"
	$IP2UTIL -o -s link show dev "$NIC" \
		| sed 's/.* RX: [^0-9]*[0-9]* *\([0-9]*\) .*/\1/'
		# the first number after RX: is the # of bytes ,
		# the second is the # of packets received
}

# watch for packet counter changes for max. OCF_RESKEY_pktcnt_timeout seconds
# returns immedeately with return code 0 if any packets were received
# otherwise 1 is returned
watch_pkt_counter () {
	local RX_PACKETS_NEW
	local RX_PACKETS_OLD
	RX_PACKETS_OLD="`get_rx_packets`"
	for n in `seq $(( $OCF_RESKEY_pktcnt_timeout * 10 ))`; do
		sleep 0.1
		RX_PACKETS_NEW="`get_rx_packets`"
		ocf_log debug "RX_PACKETS_OLD: $RX_PACKETS_OLD	RX_PACKETS_NEW: $RX_PACKETS_NEW"
		if [ "$RX_PACKETS_OLD" -ne "$RX_PACKETS_NEW" ]; then
			ocf_log debug "we received some packets."
			return 0
		fi
	done
	return 1
}

# returns list of cached ARP entries for $NIC
# sorted by age ("last confirmed")
# max. OCF_RESKEY_arping_cache_entries entries
get_arp_list () {
	$IP2UTIL -s neighbour show dev $NIC \
		| sort -t/ -k2,2n | cut -d' ' -f1 \
		| head -n $OCF_RESKEY_arping_cache_entries
		# the "used" entries in `ip -s neighbour show` are:
		# "last used"/"last confirmed"/"last updated"
}

# arping the IP given as argument $1 on $NIC
# until OCF_RESKEY_arping_count answers are received
do_arping () {
	# TODO: add the source IP
	# TODO: check for diffenrent arping versions out there
	arping -q -c $OCF_RESKEY_arping_count -w $OCF_RESKEY_arping_timeout -I $NIC $1
	# return with the exit code of the arping command 
	return $?
}

#
# Check the interface depending on the level given as parameter: $OCF_RESKEY_check_level
#
# 09: check for nonempty ARP cache
# 10: watch for packet counter changes
#
# 19: check arping_ip_list
# 20: check arping ARP cache entries
# 
# 30:  watch for packet counter changes in promiscios mode
# 
# If unsuccessfull in levels 18 and above,
# the tests for higher check levels are run.
#
if_check () {
	local arp_list
	# always check link status first
	link_status="`get_link_status`"
	ocf_log debug "link_status: $link_status (1=up, 0=down)"

	if [ $link_status -eq 0 ]; then
		ocf_log notice "link_status: DOWN"
		return $OCF_NOT_RUNNING
	fi

	# if this is an infiniband device, try ibstatus script
	if [ -n "$OCF_RESKEY_infiniband_device" ]; then
		if infiniband_status; then
			return $OCF_SUCCESS
		fi
		ocf_log info "Infiniband device $OCF_RESKEY_infiniband_device is not available, check ibstatus for more information"
		return $OCF_NOT_RUNNING	
	fi

	# if using link_status_only, skip RX count and arping related tests
	if ocf_is_true "$OCF_RESKEY_link_status_only"; then
		return $OCF_SUCCESS
	fi

	# watch for packet counter changes
	ocf_log debug "watch for packet counter changes"
	watch_pkt_counter
	if [ $? -eq 0 ]; then
		return $OCF_SUCCESS
	else 
		ocf_log debug "No packets received during packet watch timeout"
	fi

	# check arping ARP cache entries
	ocf_log debug "check arping ARP cache entries"
	arp_list=`get_arp_list`
	for ip in `echo $arp_list`; do
		do_arping $ip && return $OCF_SUCCESS
	done

	# if we get here, the ethernet device is considered not running.
	# provide some logging information
	if [ -z "$arp_list" ]; then
		ocf_log info "No ARP cache entries found to arping" 
	fi

	# watch for packet counter changes in promiscios mode
#	ocf_log debug "watch for packet counter changes in promiscios mode" 
	# be sure switch off promiscios mode in any case
	# TODO: check first, wether promisc is already on and leave it untouched.
#	trap "$IP2UTIL link set dev $NIC promisc off; exit" INT TERM EXIT
#		$IP2UTIL link set dev $NIC promisc on
#		watch_pkt_counter && return $OCF_SUCCESS
#		$IP2UTIL link set dev $NIC promisc off
#	trap - INT TERM EXIT

	# looks like it's not working (for whatever reason)
	return $OCF_NOT_RUNNING
}

#######################################################################

if_usage() {
	cat <<END
usage: $0 {start|stop|status|monitor|validate-all|meta-data}

Expects to have a fully populated OCF RA-compliant environment set.
END
}

set_cib_value() {
	local score=`expr $1 \* $OCF_RESKEY_multiplier`
	attrd_updater -n $ATTRNAME -v $score
	local rc=$?
	case $rc in
		0) ocf_log debug "attrd_updater: Updated $ATTRNAME = $score" ;;
		*) ocf_log warn "attrd_updater: Could not update $ATTRNAME = $score: rc=$rc";;
	esac
	return $rc
}

if_monitor() {
	ha_pseudo_resource $OCF_RESOURCE_INSTANCE monitor
	local pseudo_status=$?
	if [ $pseudo_status -ne $OCF_SUCCESS ]; then
		exit $pseudo_status
	fi
	
	local mon_rc=$OCF_NOT_RUNNING
	local attr_rc=$OCF_NOT_RUNNING
	local runs=0
	local start_time
	local end_time
	local sleep_time
	while [ $mon_rc -ne $OCF_SUCCESS -a $REP_COUNT -gt 0 ]
	do
		start_time=`date +%s%N`
		if_check
		mon_rc=$?
		REP_COUNT=$(( $REP_COUNT - 1 ))
		if [ $mon_rc -ne $OCF_SUCCESS -a $REP_COUNT -gt 0 ]; then
			ocf_log warn "Monitoring of $OCF_RESOURCE_INSTANCE failed, $REP_COUNT retries left."
			end_time=`date +%s%N`
			sleep_time=`echo "scale=9; ( $start_time + ( $REP_INTERVAL_S * 1000000000 ) - $end_time ) / 1000000000" | bc -q 2> /dev/null`
			sleep $sleep_time 2> /dev/null
			runs=$(($runs + 1))
		fi

		if [ $mon_rc -eq $OCF_SUCCESS -a $runs -ne 0 ]; then
			ocf_log info "Monitoring of $OCF_RESOURCE_INSTANCE recovered from error"
		fi
	done
	
	ocf_log debug "Monitoring return code: $mon_rc"
	if [ $mon_rc -eq $OCF_SUCCESS ]; then
		set_cib_value 1
		attr_rc=$?
	else
		ocf_log err "Monitoring of $OCF_RESOURCE_INSTANCE failed."
		set_cib_value 0
		attr_rc=$?
	fi

	## The resource should not fail, if the interface is down. It should fail, if the update of the CIB variable has errors.
	## To react on the interface failure you must use constraints based on the CIB variable value, not on the resource itself.
	exit $attr_rc
}

if_stop()
{
	attrd_updater -D -n $ATTRNAME
	ha_pseudo_resource $OCF_RESOURCE_INSTANCE stop
}

if_start()
{
	local rc
	ha_pseudo_resource $OCF_RESOURCE_INSTANCE start
	rc=$?
	if [ $rc -ne $OCF_SUCCESS ]; then
		ocf_exit_reason "Failure to create ethmonitor state file"
		return $rc
	fi

	# perform the first monitor during the start operation
	if_monitor
	return $?
}


if_validate() {
	check_binary $IP2UTIL
	check_binary arping
	check_binary bc
	if_init
}

case $__OCF_ACTION in
meta-data)	meta_data
		;;
usage|help)	if_usage
		exit $OCF_SUCCESS
		;;
esac

if_validate

case $__OCF_ACTION in
start)		if_start
		exit $?
		;;
stop)		if_stop
		exit $?
		;;
monitor|status)	if_monitor
		exit $?
		;;
validate-all)	exit $?
		;;
*)		if_usage
		exit $OCF_ERR_UNIMPLEMENTED
		;;
esac