Captive-Portal: add captive chains to firewall initscript

When loading the initscript of the firewall the neccessary chains for
the captive portalneed to be created.

Signed-off-by: Alexander Marx <alexander.marx@ipfire.org>

src/initscripts/system/firewall

@@ -224,6 +224,13 @@ iptables_init() {
 		iptables -A ${i} -j LOOPBACK
 	done
 
+	# Captive portal
+	iptables -N CAPTIVE_PORTAL
+	iptables -N CAPTIVE_PORTAL_CLIENTS
+	for i in INPUT FORWARD; do
+		iptables -A ${i} -j CAPTIVE_PORTAL
+	done
+
 	# Accept everything connected
 	for i in INPUT FORWARD OUTPUT; do
 		iptables -A ${i} -j CONNTRACK
@@ -337,6 +344,10 @@ iptables_init() {
 	iptables -N UPNPFW
 	iptables -A FORWARD -m conntrack --ctstate NEW -j UPNPFW
 
+	# Captive Portal
+	iptables -t nat -N CAPTIVE_PORTAL
+	iptables -t nat -A PREROUTING -j CAPTIVE_PORTAL
+
 	# RED chain, used for the red interface
 	iptables -N REDINPUT
 	iptables -A INPUT -j REDINPUT