#!/bin/sh
## check network interface status

NAGIOS_STATE_OK=0
NAGIOS_STATE_WARNING=1
NAGIOS_STATE_CRITICAL=2
NAGIOS_STATE_UNKNOWN=3

OPTIND=1

show_help="$(basename "$0") v1.0 [-h for this help] [-s speed] [-d duplex] [-m mtu]
where:
		-s speed (10/100/1000)
			default: 1000

		-d duplex (half/full)
			default: full

		-m mtu (1500)
			default: 1500

		-i interface ($string)
			default: eth0
"

while getopts "h:?:m:d:s:i:" opt;
	do
	case "$opt" in
		h|\?)
			echo $show_help;
			exit 0;
		;;
		m)	IF_EXP_MTU="$OPTARG";;
		d)	IF_EXP_DUPLEX="$OPTARG";;
		s)	IF_EXP_SPEED="$OPTARG";;
		i)	IF_IFACE_NAME="$OPTARG";;
	esac
done

shift $((OPTIND-1))

[ "$1" = "--" ] && shift

# something is not set? use defaults:
if [ -z "$IF_EXP_MTU" ]; then
	IF_EXP_MTU="1500";
fi

if [ -z "$IF_EXP_DUPLEX" ]; then
	IF_EXP_DUPLEX="full";
fi

if [ -z "$IF_EXP_SPEED" ]; then
	IF_EXP_SPEED="1000"
fi

if [ -z "$IF_IFACE_NAME" ]; then
	IF_IFACE_NAME="eth0";
fi

if [ ! -d "/sys/class/net/${IF_IFACE_NAME}/" ]; then
	echo "ERROR: no such interface \"${IF_IFACE_NAME}\"";
	exit $NAGIOS_STATE_UNKNOWN;
fi

IF_SPEED=`cat /sys/class/net/${IF_IFACE_NAME}/speed`
IF_MTU=`cat /sys/class/net/${IF_IFACE_NAME}/mtu`
IF_DUPLEX=`cat /sys/class/net/${IF_IFACE_NAME}/duplex`

if [ "$IF_SPEED" == "$IF_EXP_SPEED" ] && [ "$IF_MTU" == "$IF_EXP_MTU" ] && [ "$IF_DUPLEX" == "$IF_EXP_DUPLEX" ]; then
	echo "OK: interface \"${IF_IFACE_NAME}\" is fine (speed=$IF_EXP_SPEED, duplex=$IF_EXP_DUPLEX, mtu=$IF_EXP_MTU)";
	exit $NAGIOS_STATE_OK;
else
	echo "ERROR: problem with interface \"${IF_IFACE_NAME}\" (speed=$IF_SPEED, duplex=$IF_DUPLEX, mtu=$IF_MTU)";
	exit $NAGIOS_STATE_CRITICAL;
fi