#!/bin/sh
NSENTER=$NSENTER
CHAIN=$CHAIN
COMMENT=$COMMENT
PROTOCOL=$TYPE

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

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

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


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

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

iptables="nsenter -t $(docker inspect --format {{.State.Pid}} $NAME) -n -- /sbin/iptables-legacy -t nat";

	if $iptables --list POSTROUTING |grep ESTABLISHED |grep RELATED|grep ACCEPT ; then 
			else $iptables -I POSTROUTING -m state --state established,related -j ACCEPT;
	fi

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

if [ -n "$LINES" ] ; then
	for i in $LINES; do 
		$iptables -D PREROUTING $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

else 
	iptables="/sbin/iptables-legacy"
	
	if $iptables --list $CHAIN |grep ESTABLISHED |grep RELATED|grep ACCEPT ; then 
			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	
		done
	done
done