#!/bin/bash
# **** License ****
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 as
# published by the Free Software Foundation.
#
# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.
#
# This code was originally developed by Vyatta, Inc.
# Portions created by Vyatta are Copyright (C) 2007 Vyatta, Inc.
# All Rights Reserved.
#
# Author:	Tom Grennan <tgrennan@vyatta.com>
# Description:	firewall init 
#		this is an indirect init sub-script executed by ofr.init
#
# **** End License ****

prefix=@prefix@
exec_prefix=@exec_prefix@
bindir=@bindir@
sbindir=@sbindir@

export PATH=/usr/bin:/usr/sbin:/bin:/sbin:$bindir:$sbindir

. /lib/lsb/init-functions

ACTION=$1

declare -a modules=(
    nf_conntrack
    nf_conntrack_ftp
    nf_conntrack_tftp
    nf_nat
    nf_nat_ftp
    nf_nat_tftp
    nf_nat_proto_gre
    nf_nat_sip
    nf_nat_h323
    nf_nat_pptp)

## setup firewall & nat conntrack modules
start () {
    for mod in ${modules[@]} ; do 
	modprobe --syslog $mod
    done

    # set up notrack chains/rules for IPv4
    # by default, nothing is tracked.
    iptables -t raw -A PREROUTING -j NOTRACK
    iptables -t raw -A OUTPUT -j NOTRACK

    # set up notrack chains/rules for IPv6
    ip6tables -t raw -A PREROUTING -j NOTRACK
    ip6tables -t raw -A OUTPUT -j NOTRACK
    
    # set up post-firewall hook for IPv4
    iptables -N VYATTA_POST_FW_HOOK
    iptables -A VYATTA_POST_FW_HOOK -j ACCEPT
    iptables -A INPUT -j VYATTA_POST_FW_HOOK
    iptables -A FORWARD -j VYATTA_POST_FW_HOOK

    # set up post-firewall hook for IPv6
    ip6tables -N VYATTA_POST_FW_HOOK
    ip6tables -A VYATTA_POST_FW_HOOK -j ACCEPT
    ip6tables -A INPUT -j VYATTA_POST_FW_HOOK
    ip6tables -A FORWARD -j VYATTA_POST_FW_HOOK

    # set up pre-SNAT hook
    iptables -t nat -N VYATTA_PRE_SNAT_HOOK
    iptables -t nat -A VYATTA_PRE_SNAT_HOOK -j RETURN
    iptables -t nat -A POSTROUTING -j VYATTA_PRE_SNAT_HOOK

    # Loosen the acceptability rules for TCP sequence and ACK numbers in
    # conntrack.  This allows TCP connections through NAT to survive certain
    # cases of packet loss where conntrack can not accurately track the
    # connection state
    sysctl -q -w net.netfilter.nf_conntrack_tcp_be_liberal=1
    
    # set conntrack table size
    sysctl -q -w net.nf_conntrack_max=16384
}

case "$ACTION" in
    start) start ;;
    stop|restart|force-reload) true ;; # nothing to stop/restart
    *)	log_failure_msg "action unknown: $ACTION" ;
	false ;;
esac

exit $?

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