tunnel for iptables,redsocks

tunnel.sh

#!/bin/bash -x

if [ -z "$1" ]; then echo Argument needed. >&2; exit 1; fi
if [ -z "$(pidof redsocks)" ]; then echo Redsocks requied >&2; exit 2; fi

DEF_IF="$(/sbin/route -n |awk '/^0.0.0.0/{print $8}')"
if [ -z "$DEF_IF" ]; then echo Cannot get default interface >&2; exit 3; fi

echo "Starting tunnel to $1..."

iptables_clean() {
	iptables -t nat -F REDSOCKS
	iptables -t nat -D OUTPUT -p tcp -j REDSOCKS
	iptables -t nat -X REDSOCKS	
}

iptables_do() {
	iptables -t nat -N REDSOCKS
	iptables -t nat -A REDSOCKS -d 0.0.0.0/8 -j RETURN
	iptables -t nat -A REDSOCKS -d 10.0.0.0/8 -j RETURN
	iptables -t nat -A REDSOCKS -d 127.0.0.0/8 -j RETURN
	iptables -t nat -A REDSOCKS -d 169.254.0.0/16 -j RETURN
	iptables -t nat -A REDSOCKS -d 172.16.0.0/12 -j RETURN
	iptables -t nat -A REDSOCKS -d 192.168.0.0/16 -j RETURN
	iptables -t nat -A REDSOCKS -d 224.0.0.0/4 -j RETURN
	iptables -t nat -A REDSOCKS -d 240.0.0.0/4 -j RETURN
	iptables -t nat -A REDSOCKS -p tcp -o $DEF_IF -j DNAT --to 127.0.0.1:31338
	iptables -t nat -A OUTPUT -p tcp -j REDSOCKS
}

while true; do
	sudo -u $SUDO_USER ssh -ND 31337 $1 &
	trap "iptables_clean; kill %1; exit;" TERM INT
	trap "kill -HUP %1; wait %1;" HUP
	sleep 5
	iptables_do
	wait %1
	iptables_clean
done