#!/bin/sh
#
# Firewall script for ChilliSpot
# A Wireless LAN Access Point Controller
#
# Uses $EXTIF (eth0) as the external interface (Internet or intranet) and
# $INTIF (eth1) as the internal interface (access points).
#
#
# SUMMARY
# * All connections originating from chilli are allowed.
# * Only ssh is allowed in on external interface.
# * Nothing is allowed in on internal interface.
# * Forwarding is allowed to and from the external interface, but disallowed
#   to and from the internal interface.
# * NAT is enabled on the external interface.

IPTABLES="/sbin/iptables"
EXTIF="eth0"
INTIF="eth1"

#Flush all rules
$IPTABLES -F 
$IPTABLES -F -t nat
$IPTABLES -F -t mangle

#Set default behaviour
$IPTABLES -P INPUT DROP
$IPTABLES -P FORWARD ACCEPT
$IPTABLES -P OUTPUT ACCEPT

#Allow related and established on all interfaces (input)
$IPTABLES -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT

#Allow releated, established and ssh on $EXTIF. Reject everything else.
$IPTABLES -A INPUT -i $EXTIF -p tcp -m tcp --dport 22 --syn -j ACCEPT
$IPTABLES -A INPUT -i $EXTIF -j REJECT

#Allow related and established from $INTIF. Drop everything else.
$IPTABLES -A INPUT -i $INTIF -j DROP

#Allow http and https on other interfaces (input).
#This is only needed if authentication server is on same server as chilli
$IPTABLES -A INPUT -p tcp -m tcp --dport 80 --syn -j ACCEPT
$IPTABLES -A INPUT -p tcp -m tcp --dport 443 --syn -j ACCEPT

#Allow 3990 on other interfaces (input).
$IPTABLES -A INPUT -p tcp -m tcp --dport 3990 --syn -j ACCEPT

#Allow ICMP echo on other interfaces (input).
$IPTABLES -A INPUT -p icmp --icmp-type echo-request -j ACCEPT

#Allow everything on loopback interface.
$IPTABLES -A INPUT -i lo -j ACCEPT

# Drop everything to and from $INTIF (forward)
# This means that access points can only be managed from ChilliSpot
$IPTABLES -A FORWARD -i $INTIF -j DROP
$IPTABLES -A FORWARD -o $INTIF -j DROP

#Enable NAT on output device
$IPTABLES -t nat -A POSTROUTING -o $EXTIF -j MASQUERADE