#!/bin/bash
#   This program is free software; you can redistribute it and/or modify
#   it under the terms of the GNU General Public License as published by
#   the Free Software Foundation; either version 2 of the License, or
#   (at your option) any later version.
#
#   This program is distributed in the hope that it will be useful,
#   but WITHOUT ANY WARRANTY; without even the implied warranty of
#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#   GNU General Public License for more details.
#
#   You should have received a copy of the GNU General Public License
#   along with this program; if not, write to the Free Software
#   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

PROGNAME=`basename $0`
VERSION="version 0.93"
AUTHOR="by Radu MARINESCU radumar1001@yahoo.com"
#############################
# Program paths. If left empty the script tries to find the programs
# in the PATH. Fill in the correct paths only if needed.
#############################
#usually /bin/grep or /usr/bin/grep
GREP=""
#usually /sbin/ifconfig
IFCONFIG=""
#usually /bin/sed
SED=""
#############################

if [ ${#GREP} == 0 ] #the variable GREP is not defined; trying to find grep in the PATH
then
	GREP=`which grep 2>&1`
	GREP_EXISTS=$?
	if [ "$GREP_EXISTS" != 0 ] || [ ${#GREP} == 0 ] #grep is not in the PATH or the variable GREP is empty
	then
		echo "Error! Can't find grep."
		exit 3
	fi	
fi

if [ ${#IFCONFIG} == 0 ] #the variable IFCONFIG is not defined; trying to find ifconfig in the PATH
then
	IFCONFIG=`which ifconfig 2>&1`
	IFCONFIG_EXISTS=$?
	if [ "$IFCONFIG_EXISTS" != 0 ] || [ ${#IFCONFIG} == 0 ] #ifconfig is not in the PATH or the variable IFCONFIG is empty
	then
		echo "Error! Can't find ifconfig."
		exit 3
	fi	
fi

if [ ${#SED} == 0 ] #the variable SED is not defined; trying to find sed in the PATH
then
	SED=`which sed 2>&1`
	SED_EXISTS=$?
	if [ "$SED_EXISTS" != 0 ] || [ ${#SED} == 0 ] #sed is not in the PATH or the variable SED is empty
	then
		echo "Error! Can't find sed."
		exit 3
	fi	
fi
#############################

print_version() {
    echo "$VERSION $AUTHOR"
}

print_help() {
print_version $PROGNAME $VERSION
echo ""
echo "$PROGNAME is a Nagios plugin to network Ethernet interfaces on "
echo "Linux platforms. It uses the output of ifconfig and reports the "
echo "status of the network interface and the following parameters "
echo "as performance data: RX bytes, TX bytes, RX packets, TX packets, "
echo "RX errors and TX errors."
echo ""
echo "$PROGNAME [-v] [-h] [-i dev]"
echo ""
echo "Options:"
echo "  --version|-v)"
echo "    prints the program version"
echo "  --help|-h)"
echo "    prints this help information"
echo "  --interface|-i)"
echo "    specifies the network interface to check"
exit 3
}

if [ $# -lt 1 ]; then
    print_help
    exit 3
fi

while test -n "$1"; do
    case "$1" in
        --help|-h)
            print_help
            exit 3
            ;;
        --version|-v)
            print_version $PROGNAME $VERSION
            exit 3
            ;;
        --interface|-i)
            iface=$2
            shift
            ;;
        *)
            echo "Unknown argument: $1"
            print_help
            exit 3
            ;;
    esac
    shift
done

ETH_DATA=`$IFCONFIG $iface 2>&1`
ETH_EXISTS=$?
if [ "$ETH_EXISTS" != 0 ]
then
    echo "Error! Can't read the status of $iface"
    exit 3
fi

echo "$ETH_DATA" | $GREP "RUNNING" > /dev/null
ETH_UP=$?

RXTXBytes=`echo "$ETH_DATA" | $GREP "RX bytes" | $SED 's/^[ ]*RX bytes:\([0-9]\+\).*TX bytes:\([0-9]\+\).*$/RX_Bytes=\1B;;;; TX Bytes=\2B;;;;/'`
RXPackets=`echo "$ETH_DATA" | $GREP "RX packets" | $SED 's/^[ ]*RX packets:\([0-9]\+\)[ ]*errors:\([0-9]\+\).*$/RX_packets=\1;;;; RX_errors=\2;;;;/'`
TXPackets=`echo "$ETH_DATA" | $GREP "TX packets" | $SED 's/^[ ]*TX packets:\([0-9]\+\)[ ]*errors:\([0-9]\+\).*$/TX_packets=\1;;;; TX_errors=\2;;;;/'`

if [ "$ETH_UP" == "0" ]
then
    echo -ne "$iface RUNNING | $RXTXBytes $RXPackets $TXPackets\n"
    exit 0
else
    echo -ne "$iface NOT Running! | $RXTXBytes $RXPackets $TXPackets\n"
    exit 2
fi