#!/bin/sh

# Task type variables
NSENTER=$NSENTER
PREROUTING=$PREROUTING
POSTROUTING=$POSTROUTING

# Mandatory task variables
NAME=$NAME-$COMMENT
CHAIN=$CHAIN
COMMENT=$COMMENT
PROTOCOL=$TYPE

##############################

echo 1 > /proc/sys/net/ipv4/ip_forward

##############################

IPTABLES=/sbin/iptables-legacy

###############################

COUNT_SOURCE_IP=$(set |grep SOURCE_IP |wc -l)
COUNT_SOURCE_PORT=$(set |grep SOURCE_PORT |wc -l)
COUNT_TARGET_IP=$(set |grep TARGET_IP |wc -l)
COUNT_TARGET_PORT=$(set |grep TARGET_PORT |wc -l)

for source_ip_index in $(seq 1 $COUNT_SOURCE_IP) ; do
	if set |grep SOURCE_IP_ ; then
		SOURCE_IP=$(eval "echo \${"SOURCE_IP_$source_ip_index"}")
	fi

	for source_port_index in $(seq 1 $COUNT_SOURCE_PORT) ; do
		if set |grep SOURCE_PORT_ ; then
			SOURCE_PORT=$(eval "echo \${"SOURCE_PORT_$source_port_index"}")
		fi
	
		for target_ip_index in $(seq 1 $COUNT_TARGET_IP) ; do
			if set |grep TARGET_IP_ ; then
				TARGET_IP=$(eval "echo \${"TARGET_IP_$target_ip_index"}")                 
			fi                                                                               
	
			for target_port_index in $(seq 1 $COUNT_TARGET_PORT) ; do
				if set |grep TARGET_PORT_ ; then
					TARGET_PORT=$(eval "echo \${"TARGET_PORT_$target_port_index"}")
				fi

#############################
# NSENTER Specific settings #
if [[ "$NSENTER" == "true" ]] ; then

	if [[ "$PREROUTING" == "true" ]] || [[ "$POSTROUTING" == "true" ]] ; then
		iptables="nsenter -t $(docker inspect --format {{.State.Pid}} $NAME) -n -- $IPTABLES -t nat";
		
		if [[ "$PREROUTING" == "true" ]] ; then
			LINES=$($iptables --line-number -n | grep $COMMENT | grep PREROUTING |awk '{print $1}'| tac)

				# DELETE UNECESSARY LINES FROM PREVIOUS RULES
				if [ -n "$LINES" ] ; then
					for i in $LINES; do 
						$iptables -D $i
						sleep 0.1
					done
				fi
		
			$iptables -I PREROUTING -d $SOURCE_IP -p $PROTOCOL --dport $SOURCE_PORT -m comment --comment "$COMMENT" -j DNAT --to $TARGET_IP:$TARGET_PORT
			
		elif [[ "$POSTROUTING" == "true" ]] ; then
			LINES=$($iptables --line-number -n | grep $COMMENT | grep POSTROUTING | awk '{print $1}'| tac)

				# DELETE UNECESSARY LINES FROM PREVIOUS RULES
				if [ -n "$LINES" ] ; then
					for i in $LINES; do 
						$iptables -D $i
						sleep 0.1
					done
				fi
		
			$iptables -I POSTROUTING -d $TARGET_IP -p $PROTOCOL --dport $TARGET_PORT -m comment --comment "$COMMENT" -j MASQUERADE	

	else 
		ip_route="nsenter -t $(docker inspect --format {{.State.Pid}} $NAME) -n -- ip route";


	fi


else 
	if $IPTABLES --list $CHAIN |grep ESTABLISHED |grep RELATED|grep ACCEPT ; then 
		echo "nothing to do";
	else $IPTABLES -I $CHAIN -m state --state established,related -j ACCEPT;
	fi

	# 
	# DELETE UNECESSARY LINES FROM PREVIOUS RULES
	LINES=$($IPTABLES --line-number -n --list $CHAIN | grep $SOURCE_IP |grep $TARGET_IP |grep $PROTOCOL |grep $TARGET_PORT | awk '{print $1}'| tac)

		if [ -n "$LINES" ] ; then
			for i in $LINES; do 
				$IPTABLES -D $CHAIN $i
				sleep 0.1
			done
		fi

	$IPTABLES -I $CHAIN -s $SOURCE_IP -d $TARGET_IP -p $PROTOCOL --dport $TARGET_PORT -m comment --comment "$COMMENT" -j ACCEPT

	#############################

fi

			done # target_port
		done # target_ip
	done # source_port
done # source_ip