pandorafms/pandora_server/util/plugin/dns_plugin.sh

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#!/bin/bash
# DNS Plugin Pandora FMS Server plugin
# Default variables
TIMEOUT_DURATION=15
IP_CHECK=""
DNS_CHECK=""
DOMAIN_CHECK=""
TIME_CHECK=0
# Regular expression to validate IP address
IP_REGEX="^(25[0-5]|2[0-4][0-9]|[0-1]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[0-1]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[0-1]?[0-9][0-9]?)\.(25[0-5]|2[0-4][0-9]|[0-1]?[0-9][0-9]?)$"
# Function to display help with command-line options
function show_help {
echo "DNS Plugin for Pandora FMS Plugin server. http://pandorafms.com"
echo " "
echo "This plugin is used to check if a specific domain returns a specific IP address,"
echo "and to check how much time (in milliseconds) it takes the DNS to answer."
echo " "
echo "Syntax:"
echo " -d domain to check"
echo " -i IP address to check with the domain"
echo " -s DNS Server to check"
echo " -t Do a DNS time response check instead of a DNS resolve test"
echo " "
echo "Samples:"
echo " ./dns_plugin.sh -d example.com -i 192.168.1.1 -s 8.8.8.8"
echo " ./dns_plugin.sh -d example.com -t -s 8.8.8.8"
exit 1
}
# Function to perform DNS query and get IP addresses
function do_dns_query {
results=$(timeout "${TIMEOUT_DURATION}s" dig "@$DNS_CHECK" +nocmd "$DOMAIN_CHECK" +multiline +answer A)
echo "$results"
}
# Command-line argument processing with getopts
while getopts ":htd:i:s:" opt; do
case "$opt" in
d)
DOMAIN_CHECK=$OPTARG
;;
i)
# Validate the provided IP address
if [[ $OPTARG =~ $IP_REGEX ]]; then
IP_CHECK=$OPTARG
else
echo "The provided IP address is incorrect: $OPTARG" >&2
echo "-1"
exit 1
fi
;;
s)
# Validate the DNS server IP address
if [[ $OPTARG =~ $IP_REGEX ]]; then
DNS_CHECK=$OPTARG
else
echo "The provided DNS server IP address is incorrect: $OPTARG" >&2
echo "-1"
exit 1
fi
;;
t)
TIME_CHECK=1
;;
?)
show_help
;;
esac
done
# Check if all necessary values are provided
if [ -z "$DOMAIN_CHECK" ] || ([ -z "$IP_CHECK" ] && [ $TIME_CHECK -eq 0 ]) || [ -z "$DNS_CHECK" ]; then
echo "Missing or incomplete arguments." >&2
echo "-1"
show_help
fi
# Check if time response check should be performed
if [ $TIME_CHECK -eq 1 ]; then
results=$(do_dns_query)
RETURN_TIME=$(echo "$results" | awk '/Query time:/ {print $4}')
echo "$RETURN_TIME"
exit 0
fi
# Check if IP address check should be performed
if [ -n "$IP_CHECK" ]; then
results=$(do_dns_query)
targets=$(echo "$results" | awk '{print $5}')
found=0
for x in $targets; do
if [ "$x" == "$IP_CHECK" ]; then
found=1
break
fi
done
if [ "$found" -eq 0 ]; then
echo "0"
else
echo "1"
fi
else
# Show error if IP to check is not specified
echo "No IP to check was specified for the domain: $DOMAIN_CHECK" >&2
echo "-1"
exit 1
fi
exit 0