check_dns_responsetime

#!/bin/bash
# ======================================================================
#
# Check DNS response time
# requirements:
# - netstat
#
# ----------------------------------------------------------------------
# 2020-06-17  v1.0  <axel.hahn@iml.unibe.ch>
# ======================================================================


. `dirname $0`/inc_pluginfunctions
tmpfile=/tmp/check_netstat_out_$$
infofile=/tmp/check_netstat_out_2_$$
myHost=www.unibe.ch


# ----------------------------------------------------------------------
# MAIN
# ----------------------------------------------------------------------


# --- check param -h
if [ "$1" = "-h" ]; then
    echo "
    usage: $0 [ -w value -c value -h ]

        -w  Warning level
        -c  Critical level
        -h  this help
    "
    exit 0
fi

# set default / override from command line params
typeset -i iWarnLimit=`     ph.getValueWithParam  300 w "$@"`
typeset -i iCriticalLimit=` ph.getValueWithParam 1000 c "$@"`

rm -f $tmpfile $infofile 2>/dev/null

typeset -i iMax=0
typeset -i iTime=0

for mydns in `grep ^nameserver /etc/resolv.conf | awk '{ print $2 } ' `
do
    typeset -i iSrvMax=0
    echo "" >>$infofile

    # echo "---------- `date` $mydns " >>$infofile
    # todo loop
    for i in `seq 5`
    do
        # echo "" >>$infofile
        # echo "---------- `date` -- $mydns - $i" >>$infofile
        (time nslookup ${myHost} $mydns) >$tmpfile 2>&1

        iTime=`cat $tmpfile | grep "^real.*m.*\..*s" | cut -f 2 -d "m" | sed "s#[\.s]##g" | sed "s#^0*##g" `
        echo "$mydns #$i >>> $iTime ms" >>$infofile
        test $iTime -ge $iWarnLimit && cat $tmpfile >> $infofile

        test $iTime -gt $iSrvMax && iSrvMax=$iTime
    done

    label=`echo $mydns | sed "s#\.#-#g" `
    ph.perfadd "response-$label" "${iSrvMax}"
    test $iSrvMax -gt $iMax && iMax=$iSrvMax
done

# --- set status
ph.setStatusByLimit $iMax $iWarnLimit $iCriticalLimit

ph.status "DNS check - found maximum was $iMax ms"
cat $infofile

rm -f $tmpfile $infofile


ph.exit

# ----------------------------------------------------------------------