TP_PORT=900
TP_USER=daemon

exists()
{
	which "$1" >/dev/null 2>/dev/null
}

ipt()
{
	$IPTABLES $FW_EXTRA_PRE -C "$@" $FW_EXTRA_POST >/dev/null 2>/dev/null || $IPTABLES $FW_EXTRA_PRE -I "$@" $FW_EXTRA_POST
}

redirect_port()
{
	ipt PREROUTING -t nat -p tcp --dport $1 -j REDIRECT --to-port $2
	ipt OUTPUT -t nat -p tcp --dport $1 -m owner ! --uid-owner $TP_USER -j REDIRECT --to-port $2
}

redirect()
{
	redirect_port 80 $TP_PORT
	redirect_port 443 $TP_PORT
}

for IPTABLES in iptables ip6tables; do
	exists $IPTABLES && redirect
done