#!/bin/bash

E_OK=0;E_WARN=1;E_CRIT=2;E_UNKNOWN=3 #Коды возврата Nagios
set -o pipefail

#Defaults
TYPE="A"

usage()
{
 cat <<EOF
 This script checks dns records corresponding to given list
 usage: $0 domain list [server]
      list - addresses list (separated by comma(,))
EOF
}

if [[ -n "$1" ]]; then DOMAIN="$1"; else usage; exit $E_UNKNOWN; fi
if [[ -n "$2" ]]; then LIST="$2"; else usage; exit $E_UNKNOWN; fi
if [[ -n "$3" ]]; then SERVER="$3"; fi

res=$E_OK; txt="OK"

dnsrecs="$(host -t $TYPE $DOMAIN $SERVER|grep "$DOMAIN has address "|grep -oE '[^ ]+$'|sort|tr '\n' ','|sed s/,$//)"

if [[ $? -ne 0 ]]; then echo "DNS lookup error for command: host -t $TYPE $DOMAIN $SERVER";exit $E_UNKNOWN; fi

if [[ "$dnsrecs" != "$LIST" ]]
 then res=$E_CRIT; txt="CRIT"; check_txt=" not equal to '$LIST'"
fi

echo "$txt:Records $TYPE for $DOMAIN: '$dnsrecs'$check_txt"
exit $res