#!/bin/sh
########################################################################
# Begin $rc_base/init.d/suricata
#
# Description : Suricata Initscript
#
# Author      : Stefan Schantl <stefan.schantl@ipfire.org>
#
# Version     : 01.00
#
# Notes       :
#
########################################################################

. /etc/sysconfig/rc
. ${rc_functions}

PATH=/usr/local/sbin:/usr/local/bin:/bin:/usr/bin:/sbin:/usr/sbin; export PATH

eval $(/usr/local/bin/readhash /var/ipfire/suricata/settings)

# Name of the firewall chain.
FW_CHAIN="IPS"

# Optional options for the Netfilter queue.
NFQ_OPTS="--queue-bypass "

# Array containing the 4 possible network zones.
network_zones=( red green blue orange )

# Mark and Mask options.
MARK="0x2"
MASK="0x2"

# PID file of suricata.
PID_FILE="/var/run/suricata.pid"

# Function to get the amount of CPU cores of the system.
function get_cpu_count {
	CPUCOUNT=0

	# Loop through "/proc/cpuinfo" and count the amount of CPU cores.
	while read line; do
		[ "$line" ] && [ -z "${line%processor*}" ]  && ((CPUCOUNT++))
	done </proc/cpuinfo

	echo $CPUCOUNT
}

# Function to create the firewall rules to pass the traffic to suricata.
function generate_fw_rules {
	cpu_count=$(get_cpu_count)

	# Flush the firewall chain.
	iptables -F "$FW_CHAIN"

	# Loop through the array of network zones.
	for zone in "${network_zones[@]}"; do
		# Convert zone into upper case.
		zone_upper=${zone^^}

		# Generate variable name for checking if the IDS is
		# enabled on the zone.
		enable_ids_zone="ENABLE_IDS_$zone_upper"

		# Check if the IDS is enabled for this network zone.
		if [ "${!enable_ids_zone}" == "on" ]; then
			# Generate name of the network interface.
			network_device=$zone
			network_device+="0"

			# Assign NFQ_OPTS
			NFQ_OPTIONS=$NFQ_OPTS

			# Check if there are multiple cpu cores available.
			if [ "$cpu_count" -gt "1" ]; then
				# Balance beetween all queues.
				NFQ_OPTIONS+="--queue-balance 0:"
				NFQ_OPTIONS+=$(($cpu_count-1))
			else
				# Send all packets to queue 0.
				NFQ_OPTIONS+="--queue-num 0"
			fi

			# Create firewall rules to queue the traffic and pass to
			# the IDS.
			iptables -I "$FW_CHAIN" -i "$network_device" -m mark ! --mark "$MARK"/"$MASK" -j NFQUEUE $NFQ_OPTIONS
			iptables -I "$FW_CHAIN" -o "$network_device" -m mark ! --mark "$MARK"/"$MASK" -j NFQUEUE $NFQ_OPTIONS
		fi
	done
}

# Function to flush the firewall chain.
function flush_fw_chain {
	# Call iptables and flush the chain
	iptables -F "$FW_CHAIN"
}

case "$1" in
        start)
		# Get amount of CPU cores.
		cpu_count=$(get_cpu_count)

		# Numer of NFQUES.
		NFQUEUES=

		for i in $(seq 0 $cpu_count); do
			NFQUEUES+="-q $i "
		done

		# Check if the IDS should be started.
		if [ "$ENABLE_IDS" == "on" ]; then
			# Start the IDS.
			boot_mesg "Starting Intrusion Detection System..."
			/usr/bin/suricata -c /etc/suricata/suricata.yaml -D $NFQUEUES >/dev/null 2>/dev/null
			evaluate_retval

			# Allow reading the pidfile.
			chmod 644 $PID_FILE

			# Flush the firewall chain
			flush_fw_chain

			# Generate firewall rules
			generate_fw_rules
		fi
	;;

        stop)
		boot_mesg "Stopping Intrusion Detection System..."
		killproc -p $PID_FILE /var/run

		# Flush firewall chain.
		flush_fw_chain

		# Remove suricata control socket.              
		rm /var/run/suricata/* >/dev/null 2>/dev/null

		# Don't report returncode of rm if suricata was not started
		exit 0
        ;;
                
        status)
                statusproc /usr/bin/suricata
                ;;
                
        restart)
                $0 stop
                $0 start
                ;;
	reload)
		# Send SIGUSR2 to the suricata process to perform a reload
		# of the ruleset.
		kill -USR2 $(pidof suricata)

		# Flush the firewall chain.
		flush_fw_chain

		# Generate firewall rules.
		generate_fw_rules
		;;
                
        *)
                echo "Usage: $0 {start|stop|restart|reload|status}"
                exit 1
                ;;
esac

chmod 644 /var/log/suricata/* 2>/dev/null

# End $rc_base/init.d/suricata