#!/bin/bash
# By Brielle Bruns <bruns@2mbit.com>
# URL: http://www.sosdg.org/freestuff/firewall
# License: GPLv3
#
#    Copyright (C) 2009 - 2014  Brielle Bruns
#    Copyright (C) 2009 - 2014  The Summit Open Source Development Group
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    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.
#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.


# iptables_rules_flush (ipv6|ipv4)
# Clear all rules from iptables - be very careful in how this is called as it
# could easily lock out the user from the network.  Best way to be safe, is to
# call iptables_policy_reset first then this function.
function iptables_rules_flush {
	IP_VERSION=$1
	case $IP_VERSION in
		ipv6) VER_IPTABLES=${IP6TABLES} ; TABLE_NAMES=/proc/net/ip6_tables_names ;;
		ipv4|*) VER_IPTABLES=${IPTABLES} ; TABLE_NAMES=/proc/net/ip_tables_names ;;
	esac
	${display} GREEN "Flushing ${IP_VERSION} rules..."
	${VER_IPTABLES} -F &>/dev/null
	${VER_IPTABLES} -X &>/dev/null
	${VER_IPTABLES} -F INPUT &>/dev/null
	${VER_IPTABLES} -F OUTPUT &>/dev/null
	${VER_IPTABLES} -F FORWARD &>/dev/null
	${VER_IPTABLES} -t nat -F &>/dev/null
	${VER_IPTABLES} -t nat -X &>/dev/null
	${VER_IPTABLES} -t mangle -F &>/dev/null
	${VER_IPTABLES} -t mangle -X &>/dev/null
	${VER_IPTABLES} -P INPUT ACCEPT &>/dev/null
	${VER_IPTABLES} -P OUTPUT ACCEPT &>/dev/null
	${VER_IPTABLES} -P FORWARD ACCEPT &>/dev/null
	#for i in `cat $TABLE_NAMES`; do
	#	${VER_IPTABLES} -F -t $i &>/dev/null
	#done
	#${VER_IPTABLES} -X
}

# iptables_policy_set (ipv6|ipv4) (ACCEPT|DROP)
# Sets all policy rules to either ACCEPT or DROP for ipv4 or ipv6
# If no policy given, assume ACCEPT
function iptables_policy_reset {
	IP_VERSION=$1
	SET_POLICY=${2=ACCEPT}
	case $IP_VERSION in
		ipv6) VER_IPTABLES=${IP6TABLES} ;;
		ipv4|*) VER_IPTABLES=${IPTABLES} ;;
	esac
	${display_c} RED "Setting ${IP_VERSION} policies to ${SET_POLICY}..."
	${VER_IPTABLES} --policy INPUT ${SET_POLICY}
	${VER_IPTABLES} --policy OUTPUT ${SET_POLICY}
	${VER_IPTABLES} --policy FORWARD ${SET_POLICY}
}

# setup_iptables_chains (ipv4|ipv6)
# Creates the default chains when called
function setup_iptables_chains {
	IP_VERSION=$1
	case $IP_VERSION in
		ipv6) VER_IPTABLES=${IP6TABLES};
				IPVER="6" ;;
		ipv4|*) VER_IPTABLES=${IPTABLES}
				IPVER="4" ;;
	esac
	# Create the actual chains
	${display} GREEN "Setting up chains for ${IP_VERSION}..."
	${VER_IPTABLES} -N ${InPreRules}
	${VER_IPTABLES} -N ${OutPreRules}
	${VER_IPTABLES} -N ${InEasyBlock}
	${VER_IPTABLES} -N ${OutEasyBlock}
	${VER_IPTABLES} -N ${InFilter}
	${VER_IPTABLES} -N ${OutFilter}
	${VER_IPTABLES} -N ${FwdFilter}
	${VER_IPTABLES} -N ${NAT} -t nat
	${VER_IPTABLES} -N ${PortForward} -t nat
	${VER_IPTABLES} -N ${InPostRules}
	${VER_IPTABLES} -N ${OutPostRules}
	
	# Set up rules - the order matters - we do it separately here
	# for easy viewing of order
	if [ -x ${FWCONFIGDIR}/ipv${IPVER}/custom/prerun.sh ]; then . ${FWCONFIGDIR}/ipv${IPVER}/custom/prerun.sh; fi
	${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} Setting up InPreRules"
	${VER_IPTABLES} -A INPUT -j ${InPreRules}
	${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} Setting up OutPreRules"
	${VER_IPTABLES} -A OUTPUT -j ${OutPreRules}
	if [ -x ${FWCONFIGDIR}/ipv${IPVER}/custom/easyblock.sh ]; then . ${FWCONFIGDIR}/ipv${IPVER}/custom/easyblock.sh; fi
	${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} Setting up InEasyBlock"
	${VER_IPTABLES} -A INPUT -j ${InEasyBlock}
	${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} Setting up OutEasyBlock"
	${VER_IPTABLES} -A OUTPUT -j ${OutEasyBlock}
	if [ -x ${FWCONFIGDIR}/ipv${IPVER}/custom/filter.sh ]; then . ${FWCONFIGDIR}/ipv${IPVER}/custom/filter.sh; fi
	${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} Setting up InFilter"
	${VER_IPTABLES} -A INPUT -j ${InFilter}
	${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} Setting up OutFilter"
	${VER_IPTABLES} -A OUTPUT -j ${OutFilter}
	${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} Setting up FwdFilter"
	${VER_IPTABLES} -A FORWARD -j ${FwdFilter}
	if [ -x ${FWCONFIGDIR}/ipv${IPVER}/custom/nat.sh ]; then . ${FWCONFIGDIR}/ipv${IPVER}/custom/nat.sh; fi
	${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} Setting up NAT"
	${VER_IPTABLES} -A POSTROUTING -t nat -j ${NAT}
	if [ -x ${FWCONFIGDIR}/ipv${IPVER}/custom/portfw.sh ]; then . ${FWCONFIGDIR}/ipv${IPVER}/custom/portfw.sh; fi
	${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} Setting up PortForward"
	${VER_IPTABLES} -A PREROUTING -t nat -j ${PortForward}
	if [ -x ${FWCONFIGDIR}/ipv${IPVER}/custom/postrun.sh ]; then . ${FWCONFIGDIR}/ipv${IPVER}/custom/postrun.sh; fi
	${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} Setting up InPostRules"
	${VER_IPTABLES} -A INPUT -j ${InPostRules}
	${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} Setting up OutPostRules"
	${VER_IPTABLES} -A OUTPUT -j ${OutPostRules}
}

function allow_all_loopback {
	IP_VERSION=$1
	case $IP_VERSION in
		ipv6) VER_IPTABLES=${IP6TABLES};
				IPVER="6" ;;
		ipv4|*) VER_IPTABLES=${IPTABLES}
				IPVER="4" ;;
	esac
	${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} loaded"
	${VER_IPTABLES} -A ${InPreRules} -i lo -j ACCEPT
	${VER_IPTABLES} -A ${OutPreRules} -o lo -j ACCEPT
}

function allow_trusted_hosts {
	IP_VERSION=$1
		case $IP_VERSION in
		ipv6) VER_IPTABLES=${IP6TABLES};
				IPVER="6" ;;
		ipv4|*) VER_IPTABLES=${IPTABLES}
				IPVER="4" ;;
	esac
	${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} loading"
	if [ -e "${FWCONFIGDIR}/ipv${IPVER}/trusted.conf" ]; then
		for i in `grep -v "\#" "${FWCONFIGDIR}/ipv${IPVER}/trusted.conf"`; do
			${VER_IPTABLES} -A ${InPreRules} -s $i -j ACCEPT
			${VER_IPTABLES} -A ${OutPreRules} -d $i -j ACCEPT
		done
		${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} done"
	else
		${display} RED "File Missing: ${FWCONFIGDIR}/ipv${IPVER}/trusted.conf"
		${display} RED "Error: can not load trusted hosts file."
		${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} failed"
	fi
}
function enable_mss_clamp {
	IP_VERSION=$1
		case $IP_VERSION in
		ipv6) VER_IPTABLES=${IP6TABLES};
				IPVER="6" ;;
		ipv4|*) VER_IPTABLES=${IPTABLES}
				IPVER="4" ;;
	esac
	${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} loading"
	if [ -e "${FWCONFIGDIR}/ipv${IPVER}/mss-clamp.conf" ]; then
		${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} read ${FWCONFIGDIR}/ipv${IPVER}/mss-clamp.conf successful"
		while read -r interface mss type; do
			[[ ${interface} = \#* ]] && continue
			[[ ${interface} = "" ]] && continue
			[[ ${mss} == "-" ]] && mss="1400:1536"
			[[ ${type} == "-" ]] && type="${OutFilter}"
			[[ ${type} == "out" ]] && type="${OutFilter}"
			[[ ${type} == "fwd" ]] && type="${FwdFilter}"
			${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} Read: ${interface} ${mss} ${type}"
			${VER_IPTABLES} -A ${type} -p tcp --tcp-flags SYN,RST SYN -j TCPMSS \
				--clamp-mss-to-pmtu -o ${interface} -m tcpmss --mss ${mss}
		done < "${FWCONFIGDIR}/ipv${IPVER}/mss-clamp.conf"

		${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} done"
	else
		${display} RED "File Missing: ${FWCONFIGDIR}/ipv${IPVER}/mss-clamp.conf"
		${display} RED "Error: can not load mss clamp file."
		${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} failed"
	fi
}

function allow_resolvconf_servers {
		IP_VERSION=$1
		case $IP_VERSION in
		ipv6) VER_IPTABLES=${IP6TABLES};
				IPVER="6" ;;
		ipv4|*) VER_IPTABLES=${IPTABLES}
				IPVER="4" ;;
	esac
	${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} loading"
	[[ ${IP_VERSION} == "ipv4" ]] && ResolvConfFile="${ResolvConfv4File}"
	[[ ${IP_VERSION} == "ipv6" ]] && ResolvConfFile="${ResolvConfv6File}"
	${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} Using ${ResolvConfFile} as resolv.conf"
	while read -r type server; do
		[[ ${type} != "nameserver" ]] && continue
		[[ ${type} = "" ]] && continue
		([[ ${server} =~ ":" ]] && [[ ${IP_VERSION} = "ipv4" ]]) && continue
		([[ ! ${server} =~ ":" ]] && [[ ${IP_VERSION} = "ipv6" ]]) && continue
		
		use_conntrack="no"
		([[ ${IP_VERSION} == "ipv4" ]] && [[ ${Enablev4ConnectionTracking} == "yes" ]]) && use_conntrack="yes"
		([[ ${IP_VERSION} == "ipv6" ]] && [[ ${Enablev6ConnectionTracking} == "yes" ]]) && use_conntrack="yes"

		if [[ ${use_conntrack} == "yes" ]]; then
			${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} Added ${server} to conntrack list for DNS traffic"
			${VER_IPTABLES} -A ${OutPreRules} -p udp -d ${server} --dport 53 ${M_STATE} ${C_STATE} NEW,ESTABLISHED -j ACCEPT
			${VER_IPTABLES} -A ${InPreRules} -p udp -s ${server} --sport 53 ${M_STATE} ${C_STATE} ESTABLISHED,RELATED -j ACCEPT
		else
			${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} Added ${server} to DNS client trusted list"
			${VER_IPTABLES} -A ${OutPreRules} -p udp -s ${server} --sport 1024:65535 --dport 53 -j ACCEPT
			${VER_IPTABLES} -A ${InPreRules} -p udp -d ${server} --dport 1024:65535 --sport 53 -j ACCEPT
			#${VER_IPTABLES} -A ${OutPreRules} -p tcp -s ${server} --sport 1024:65535 --dport 53 -j ACCEPT
			#${VER_IPTABLES} -A ${InPreRules} -p tcp -d ${server} --dport 1024:65535 --sport 53 -j ACCEPT
		fi
		done < "${ResolvConfFile}"
	${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} done"
}

function allow_dnsclient_manual {
	IP_VERSION=$1
		case $IP_VERSION in
		ipv6) VER_IPTABLES=${IP6TABLES};
				IPVER="6" ;;
		ipv4|*) VER_IPTABLES=${IPTABLES}
				IPVER="4" ;;
	esac
	DNS_SERVERS="$2"
	${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} loading"
	for i in ${DNS_SERVERS}; do
		${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} Added ${i} to DNS client trusted list"
		${VER_IPTABLES} -A ${OutPreRules} -p udp -s ${i} --sport 1024:65535 --dport 53 -j ACCEPT
		${VER_IPTABLES} -A ${InPreRules} -p udp -d ${i} --dport 1024:65535 --sport 53 -j ACCEPT
		${VER_IPTABLES} -A ${OutPreRules} -p tcp -s ${i} --sport 1024:65535 --dport 53 -j ACCEPT
		${VER_IPTABLES} -A ${InPreRules} -p tcp -d ${i} --dport 1024:65535 --sport 53 -j ACCEPT
	done
	${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} done"
}

function enable_easyblock {
	IP_VERSION=$1
		case $IP_VERSION in
		ipv6) VER_IPTABLES=${IP6TABLES};
				IPVER="6" ;;
		ipv4|*) VER_IPTABLES=${IPTABLES}
				IPVER="4" ;;
	esac
	${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} loading"
	if [ -e "${FWCONFIGDIR}/ipv${IPVER}/easyblock.conf" ]; then
		${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} read ${FWCONFIGDIR}/ipv${IPVER}/easyblock.conf successful"
		while read -r direction interface address port protocol; do
			[[ ${direction} = \#* ]] && continue
			[[ ${direction} = "" ]] && continue
			([[ ${direction} != "IN" ]] && [[ ${direction} != "OUT" ]]) \
					&& ${display} RED "easyblock.conf: Error - must begin with IN/OUT: ${DEFAULT_COLOR}${direction} ${interface} ${address} ${port} ${protocol}" && continue

			# Do some creative work with variables to make building the iptables rules fairly painless
			[[ ${port} != "-" ]] && port="--dport ${port}"
			([[ ${address} != "-" ]] && [[ ${direction} == "IN" ]]) && address="-s ${address}"
			([[ ${address} != "-" ]] && [[ ${direction} == "OUT" ]]) && address="-d ${address}"
			([[ ${interface} != "-" ]] && [[ ${direction} == "IN" ]]) && interface="-i ${interface}"
			([[ ${interface} != "-" ]] && [[ ${direction} == "OUT" ]]) && interface="-o ${interface}"
			[[ ${direction} == "OUT" ]] && chain="${OutEasyBlock}"
			[[ ${direction} == "IN" ]] && chain="${InEasyBlock}"
			[[ ${protocol} != "-" ]] && protocol="-p ${protocol}"
			
			${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} Read: ${direction} ${interface} ${address} ${port} ${protocol}"
			
			# Blank variables that we're not going to use.
			[[ ${interface} == "-" ]] && interface=""
			[[ ${port} == "-" ]] && port=""
			[[ ${address} == "-" ]] && address=""
			[[ ${protocol} == "-" ]] && protocol=""
			
			${VER_IPTABLES} -A ${chain} ${interface} ${address} ${protocol} ${port} -j DROP
			
		done < "${FWCONFIGDIR}/ipv${IPVER}/easyblock.conf"
		${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} done"
	fi
}

function enable_filtering {
	IP_VERSION=$1
		case $IP_VERSION in
		ipv6) VER_IPTABLES=${IP6TABLES};
				IPVER="6" ;;
		ipv4|*) VER_IPTABLES=${IPTABLES}
				IPVER="4" ;;
	esac
	${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} loading"
	if [ -e "${FWCONFIGDIR}/ipv${IPVER}/acl.conf" ]; then
		${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} read ${FWCONFIGDIR}/ipv${IPVER}/acl.conf successful"
		while read -r direction action interface srcaddress srcport dstaddress dstport protocol; do
			[[ ${direction} = \#* ]] && continue
			[[ ${direction} = "" ]] && continue
			([[ ${direction} != "IN" ]] && [[ ${direction} != "OUT" ]]) \
					&& ${display} RED "acl.conf: Error - must begin with IN/OUT: ${DEFAULT_COLOR}${direction} ${action} ${interface} ${srcaddress} ${srcport} ${dstaddress} ${dstport} ${protocol}" && continue
			([[ ${action} != "ACCEPT" ]] && [[ ${action} != "DROP" ]]) \
					&& ${display} RED "acl.conf: Error - action must be either ACCEPT or DROP : ${DEFAULT_COLOR}${direction} ${action} ${interface} ${srcaddress} ${srcport} ${dstaddress} ${dstport} ${protocol}" && continue

			# Do some creative work with variables to make building the iptables rules fairly painless
			[[ ${dstport} != "-" ]] && dstport="--dport ${dstport}"
			[[ ${srcport} != "-" ]] && srcport="--sport ${srcport}"
			[[ ${srcaddress} != "-" ]] && srcaddress="-s ${srcaddress}"
			[[ ${dstaddress} != "-" ]] && dstaddress="-d ${dstaddress}"
			([[ ${interface} != "-" ]] && [[ ${direction} == "IN" ]]) && interface="-i ${interface}"
			([[ ${interface} != "-" ]] && [[ ${direction} == "OUT" ]]) && interface="-o ${interface}"
			[[ ${direction} == "OUT" ]] && chain="${OutFilter}"
			[[ ${direction} == "IN" ]] && chain="${InFilter}"
			[[ ${protocol} != "-" ]] && protocol="-p ${protocol}"
			
			${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR}${direction} ${action} ${interface} ${srcaddress} ${srcport} ${dstaddress} ${dstport} ${protocol}"
			
			# Blank variables that we're not going to use.
			[[ ${interface} == "-" ]] && interface=""
			[[ ${dstport} == "-" ]] && dstport=""
			[[ ${srcport} == "-" ]] && srcport=""
			[[ ${dstaddress} == "-" ]] && dstaddress=""
			[[ ${srcaddress} == "-" ]] && srcaddress=""
			[[ ${protocol} == "-" ]] && protocol=""
			
			${VER_IPTABLES} -A ${chain} ${interface} ${protocol} ${srcaddress} ${srcport} ${dstaddress} ${dstport} -j ${action}
		done < "${FWCONFIGDIR}/ipv${IPVER}/acl.conf"
		${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} done"
	fi
}

function enable_forwarding {
	IP_VERSION=$1
		case $IP_VERSION in
		ipv6) VER_IPTABLES=${IP6TABLES};
				IPVER="6" ;;
		ipv4|*) VER_IPTABLES=${IPTABLES}
				IPVER="4" ;;
	esac
	${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} loading"
	if [ -e "${FWCONFIGDIR}/ipv${IPVER}/forward.conf" ]; then
		${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} read ${FWCONFIGDIR}/ipv${IPVER}/forward.conf successful"
		while read -r action srcinterface srcaddress dstinterface dstaddress bidirectional; do
			[[ ${action} = \#* ]] && continue
			[[ ${action} = "" ]] && continue
			([[ ${action} != "ACCEPT" ]] && [[ ${action} != "DROP" ]]) \
					&& ${display} RED "acl.conf: Error - action must be either ACCEPT or DROP : ${DEFAULT_COLOR}${action} ${srcinterface} ${srcaddress} ${dstinterface} ${srcaddress}" && continue

			# Do some creative work with variables to make building the iptables rules fairly painless
			([[ ${bidirectional} == "yes" ]] && [[ ${srcaddress} != "-" ]]) && revsrcaddress="-d ${srcaddress}"
			([[ ${bidirectional} == "yes" ]] && [[ ${dstaddress} != "-" ]]) && revdstaddress="-s ${dstaddress}"
			([[ ${bidirectional} == "yes" ]] && [[ ${dstinterface} != "-" ]]) && revdstinterface="-i ${dstinterface}"
			([[ ${bidirectional} == "yes" ]] && [[ ${srcinterface} != "-" ]]) && revsrcinterface="-o ${srcinterface}"
			[[ ${srcaddress} != "-" ]] && srcaddress="-s ${srcaddress}"
			[[ ${dstaddress} != "-" ]] && dstaddress="-d ${dstaddress}"
			[[ ${srcinterface} != "-" ]] && srcinterface="-i ${srcinterface}"
			[[ ${dstinterface} != "-" ]] && dstinterface="-o ${dstinterface}"
			
			${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR}${action} ${srcinterface} ${srcaddress} ${dstinterface} ${srcaddress}"
			
			# Blank variables that we're not going to use.
			[[ ${srcinterface} == "-" ]] && srcinterface=""
			[[ ${dstinterface} == "-" ]] && dstinterface=""
			[[ ${dstaddress} == "-" ]] && dstaddress=""
			[[ ${srcaddress} == "-" ]] && srcaddress=""
			[[ ${bidirectional} == "-" ]] && bidirectional="no"
			
			${VER_IPTABLES} -A ${FwdFilter} ${srcinterface} ${srcaddress} ${dstinterface} ${dstaddress} -j ${action}
			[[ ${bidirectional} == "yes" ]] && ${VER_IPTABLES} -A ${FwdFilter} ${revsrcinterface} ${revsrcaddress} ${revdstinterface} ${revdstaddress} -j ${action}
		done < "${FWCONFIGDIR}/ipv${IPVER}/forward.conf"
		${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} done"
	fi
}

function enable_nat {
	IP_VERSION=$1
		case $IP_VERSION in
		ipv6) VER_IPTABLES=${IP6TABLES};
				IPVER="6" ;;
		ipv4|*) VER_IPTABLES=${IPTABLES}
				IPVER="4" ;;
	esac
	${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} loading"
	([[ ${IPVER} == "4" ]] && [[ ${Enablev4ConnectionTracking} != "yes" ]]) && ${display} RED "${FUNCNAME}: ERROR:${DEFAULT_COLOR} Unable to load NAT rules if Enablev4ConnectionTracking=no" && return 1
	([[ ${IPVER} == "6" ]] && [[ ${Enablev6ConnectionTracking} != "yes" ]]) && ${display} RED "${FUNCNAME}: ERROR:${DEFAULT_COLOR} Unable to load NAT rules if Enablev6ConnectionTracking=no" && return 1

	if [ -e "${FWCONFIGDIR}/ipv${IPVER}/nat.conf" ]; then
		${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} read ${FWCONFIGDIR}/ipv${IPVER}/nat.conf successful"
		while read -r type srcinterface srcaddress dstinterface dstaddress; do
			[[ ${type} = \#* ]] && continue
			[[ ${type} = "" ]] && continue
			([[ ${type} != "SNAT" ]] && [[ ${type} != "MASQ" ]] && [[ ${type} != "NETMAP" ]]) \
					&& ${display} RED "nat.conf: Error - must begin with SNAT/MASQ/NETMAP: ${DEFAULT_COLOR}${type} ${srcinterface} ${srcaddress} ${dstinterface} ${dstaddress}" && continue

			# Do some creative work with variables to make building the iptables rules fairly painless
			[[ ${srcinterface} != "-" ]] && srcinterface="-i ${srcinterface}"
			[[ ${dstinterface} != "-" ]] && dstinterface="-o ${dstinterface}"
			([[ ${srcaddress} != "-" ]] && [[ ${type} != "NETMAP" ]]) && srcaddress="-s ${srcaddress}"
			
			([[ ${dstinterface} != "-" ]] && [[ ${type} == "MASQ" ]]) && action="-j MASQUERADE" 
			([[ ${dstinterface} == "-" ]] && [[ ${type} == "MASQ" ]]) && \
					${display} RED "nat.conf: Error - MASQ rule can not have empty destination interface: ${DEFAULT_COLOR}${type} ${srcinterface} ${srcaddress} ${dstinterface} ${dstaddress}" \
					&& continue

			([[ ${dstaddress} != "-" ]] && [[ ${type} == "SNAT" ]]) && action="-j SNAT" && dstaddress="--to-source ${dstaddress}"
			([[ ${dstaddress} == "-" ]] && [[ ${type} == "SNAT" ]]) && \
					${display} RED "nat.conf: Error - SNAT rule can not have empty destination address: ${DEFAULT_COLOR}${type} ${srcinterface} ${srcaddress} ${dstinterface} ${dstaddress}" \
					&& continue

			([[ ${srcaddress} != "-" ]] && [[ ${dstaddress} != "-" ]] && [[ ${type} == "NETMAP" ]]) && action="-j NETMAP" && srcaddress="-d ${srcaddress}" && dstaddress="--to ${dstaddress}"
			
			
			${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR}${direction} ${action} ${interface} ${srcaddress} ${srcport} ${dstaddress} ${dstport} ${protocol}"
			
			# Blank variables that we're not going to use.
			[[ ${srcinterface} == "-" ]] && srcinterface=""
			[[ ${dstinterface} == "-" ]] && dstinterface=""
			[[ ${dstaddress} == "-" ]] && dstaddress=""
			[[ ${srcaddress} == "-" ]] && srcaddress=""
			
			${VER_IPTABLES} -A ${NAT} -t nat ${srcaddress} ${action} ${dstinterface} ${dstaddress}
			${VER_IPTABLES} -A ${FwdFilter} ${M_STATE} ${C_STATE} RELATED,ESTABLISHED ${srcinterface} ${srcaddress} ${dstinterface} -j ACCEPT
			done < "${FWCONFIGDIR}/ipv${IPVER}/nat.conf"
		${debug} ${DebugColor} "${FUNCNAME}:${DEFAULT_COLOR} done"
	fi
		
}