#!/bin/bash
# $Header: $
# vim:nu:ai:sw=4:ts=4:
#
# Nagios check script to check whether a given interface has a given IP address
# Created by Wolfram Schlich <wschlich@gentoo.org>
# Distributed under the terms of the GNU General Public License v3
#
# External dependencies:
# - ip
# - egrep
#

##
## nagios state specific exit codes
##

declare -i state_ok=0
declare -i state_warning=1
declare -i state_critical=2
declare -i state_unknown=3
declare -i state_dependent=4

##
## functions
##

function usage() {
	echo
	echo "Usage: ${0##*/} <interface> <ipaddr/subnet-mask>"
	echo
}

function checkargs() {
	if [[ -z "${iface}" || -z "${ipaddr}" ]]; then
		usage
		exit ${state_unknown}
	fi
}

##
## main()
##

if [[ ! -x "$(type -p ip 2>/dev/null)" ]]; then
	echo "ERROR: 'ip' not executable"
	exit ${state_unknown}
fi

if [[ ! -x "$(type -p egrep 2>/dev/null)" ]]; then
	echo "ERROR: 'egrep' not executable"
	exit ${state_unknown}
fi

iface="${1}"; shift
ipaddr="${1}"; shift

checkargs

if ! ip link show dev ${iface} >&/dev/null; then
	echo "CRITICAL - interface '${iface}' does NOT EXIST!"
	exit ${state_critical}
elif ! ip link show dev ${iface} 2>/dev/null | egrep "[[:space:]]${iface}:.*(,|<)UP(,|>)" >&/dev/null; then
	echo "CRITICAL - interface '${iface}' is DOWN!"
	exit ${state_critical}
elif ! ip addr show dev ${iface} 2>/dev/null | egrep "inet6?[[:space:]]${ipaddr}[[:space:]]" >&/dev/null; then
	echo "CRITICAL - interface '${iface}' does not have IP address '${ipaddr}' configured!"
	exit ${state_critical}
else
	echo "OK - interface '${iface}' has IP address '${ipaddr}' configured properly"
	exit ${state_ok}
fi

## should never reach this
echo "ERROR - there's an error in the matrix!"
exit ${state_unknown}