#!/bin/sh
#
# Copyright (c) 2015 Babak Farrokhi.  All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in the
#    documentation and/or other materials provided with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS "AS IS" AND
# ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
# OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
# HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
# OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
#
#
# March-2017 @farrokhi
# This plugin extracts "ip input" buffer overruns using sysctl and feeds
# to munin (or any other compatible agent) for graphing
#
# Buffer overrung on IP Input happens when CPU is not fast enough
# to pick ip packet from queue. This can be observed by seeing a 
# CPU hogging "task queue" process in top.
#
# Magic markers:
#%# family=auto
#%# capabilities=autoconf 


SCRIPT_NAME=$(basename $0)

if [ $# -lt 1 ]; then

	DROPS=`sysctl -n net.inet.ip.intr_queue_drops`
	echo ip_idrops.value ${DROPS}


elif [ "$1" == "autoconf" ]; then
   echo yes
   exit 0

elif [ "$1" == "config" ]; then

	echo "graph_title IP Input Drops"
	echo "graph_args --lower-limit 0 --base 1000"
	echo "graph_vlabel packets / second"
	echo "graph_category system"

	echo ip_idrops.label "Input Drops"
	echo ip_idrops.type DERIVE
	echo ip_idrops.min 0

fi