#!/bin/sh

#
# This will be universal firewalling script for Linux kernel (iptables) in near future
# Can be started by init or by hand.
#
# Developed by Lubomir Host 'rajo' <rajo AT platon.sk>
# Copyright (c) 2003-2006 Platon SDG, http://platon.sk/
# Licensed under terms of GNU General Public License.
# All rights reserved.
#
# $Platon: scripts/shell/firewall/fw-universal.sh,v 2.49 2006-10-04 09:23:25 rajo Exp $
#
# Changelog:
# 2003-10-24 - created
#

DESC="firewall"
PATH=/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin

DEFAULT_FIREWALL_CONFIG="${DEFAULT_FIREWALL_CONFIG:=/etc/default/firewall}"
DEFAULT_CACHE_DIR="${DEFAULT_CACHE_DIR:=/var/cache/firewall}"

if [ -f "$DEFAULT_FIREWALL_CONFIG" ]; then
	echo "Reading config file $DEFAULT_FIREWALL_CONFIG"
	. $DEFAULT_FIREWALL_CONFIG
fi

#
# Default configuration values:
#

DEFAULT_POLICY="${DEFAULT_POLICY:=DROP}"
# which modules to load
MODULES="${MODULES:=}"
MODULES_LOADING="${MODULES_LOADING:=yes}"
MODULES_REMOVING="${MODULES_REMOVING:=no}"

LOG_LIMIT="${LOG_LIMIT:=-m limit --limit 12/h --limit-burst 10 -j LOG --log-level notice --log-prefix}"

# Paths:
#IPTABLES=":" # for testing only - does nothing
IPTABLES="${IPTABLES:=$DEBUG/sbin/iptables}"
IPTABLES_SAVE="${IPTABLES_SAVE:=$DEBUG/sbin/iptables-save}"
IPTABLES_RESTORE="${IPTABLES_RESTORE:=$DEBUG/sbin/iptables-restore}"

if [ "x$LOGGING" = "xoff" ]; then
	IPTABLES_LOG=": log turned off"
else
	IPTABLES_LOG="${IPTABLES_LOG:=$DEBUG/sbin/iptables}"
fi
IFCONFIG="${IFCONFIG:=/sbin/ifconfig}"
DEPMOD="${DEPMOD:=/sbin/depmod}"
MODPROBE="${MODPROBE:=/sbin/modprobe}"
RMMOD="${RMMOD:=/sbin/rmmod}"
AWK="${AWK:=/usr/bin/awk}"
PERL="${PERL:=/usr/bin/perl}"

# loopback interface
LO_IFACE="${LO_IFACE:=lo}"
# Hide NAT clients behind firewall
NAT_SET_TTL="${NAT_SET_TTL:=no}"

#
# CONSTANTS - Do not edit
#
ANYWHERE="0.0.0.0/0"				# Match any IP address
BROADCAST_SRC="0.0.0.0"				# Broadcast Source Address
BROADCAST_DEST="255.255.255.255"	# Broadcast Destination Address
CLASS_A="10.0.0.0/8"				# Class-A Private (RFC-1918) Networks
CLASS_B="172.16.0.0/12"				# Class-B Private (RFC-1918) Networks
CLASS_C="192.168.0.0/16"			# Class-C Private (RFC-1918) Networks
CLASS_D_MULTICAST="224.0.0.0/4"		# Class-D Multicast Addresses
CLASS_E_RESERVED_NET="240.0.0.0/5"	# Class-E Reserved Addresses
PRIVPORTS="0:1023"					# Well-Known, Privileged Port Range
UNPRIVPORTS="1024:65535"			# Unprivileged Port Range
TRACEROUTE_SRC_PORTS="32769:65535"	# Traceroute Source Ports
TRACEROUTE_DEST_PORTS="33434:33523"	# Traceroute Destination Ports


# allow some ICMP packets - needed for ping etc.
ACCEPT_ICMP_PACKETS="${ACCEPT_ICMP_PACKETS:=echo-reply destination-unreachable echo-request time-exceeded}"

print_first()
{ # {{{
	echo $1
} # }}}

get_first_ip_addr()
{ # {{{
	varname="$1"
	print_first `echo ${!varname} | sort -g`
} # }}}

# load necessary modules from $MODULES variable
load_modules()
{ # {{{
	if [ "e$MODULES_LOADING" = "eyes" ]; then
		echo "# Loading modules"
		for mod in $MODULES; do
			echo "	$MODPROBE $mod"
			$MODPROBE $mod
		done
	fi
} # }}}

load_cache()
{ # {{{
		
	if [ ! -d "$DEFAULT_CACHE_DIR" ]; then
		mkdir -p "$DEFAULT_CACHE_DIR";
	fi

	config=`cat $DEFAULT_FIREWALL_CONFIG $0`; # config file and firewalling script
	md5key=`echo "config = '$config' parsed_interfaces ='$parsed_interfaces' parsed_routes='$parsed_routes'" | md5sum | $AWK '{ print $1; }'`;
	CACHE_FILE="$DEFAULT_CACHE_DIR/$md5key"

	#echo "CACHE_FILE=$CACHE_FILE"

	if [ -f "$CACHE_FILE" ]; then
		echo "Loading rules from cache file $CACHE_FILE"
		$IPTABLES_RESTORE -c < $CACHE_FILE;
		forward_on # this has nothing to do with IPtables rules, we need to run them explicitly
		exit 0;
	fi
} # }}}

# unload necessary modules from $MODULES variable
unload_modules()
{ # {{{
	# reverse modules
	if [ "e$MODULES_REMOVING" = "eyes" ]; then
		echo "# Removing modules"
		R_MODULES=`echo "$MODULES" | tr ' ' '\012' | tac | tr '\012' ' '`
		for mod in $R_MODULES; do
			echo "	$RMMOD $mod"
			$RMMOD $mod
		done
	fi
} # }}}

# print status of detected interfaces
print_iface_status()
{ # {{{
	# Print interfaces:
	echo "# iface	| IP addr	| Gateway	| broadcast	| netmask	| HW addr"
	for iface in $interfaces; do
		IPS="IP_$iface";
		for IP in ${!IPS}; do
			Gateway="Gateway_$iface"; Bcast="Bcast_$iface"; Mask="Mask_$iface"; HWaddr="HWaddr_$iface";
			echo "$iface	| ${IP}	| ${!Gateway}	| ${!Bcast}	| ${!Mask}	| ${!HWaddr}"
		done
	done
} # }}}

# set default policy (variable $DEFAULT_POLICY)
set_default_policy()
{ # {{{
	# Set default policy
	for chain in INPUT OUTPUT FORWARD; do
		$IPTABLES -P $chain $DEFAULT_POLICY
	done
} # }}}

antispoof_on()
{ # {{{
	for interface in /proc/sys/net/ipv4/conf/*/rp_filter; do
		echo "1" > ${interface}
	done
} # }}}

# Turn on IP packets forwarding
forward_on()
{ # {{{
	# NAT requires turn on IP forwarding
	if [ ! -z "$NAT_LAN_IFACE" ]; then
		echo -en "NAT: Enabling packet forwarding..."
		echo 1 > /proc/sys/net/ipv4/ip_forward
		echo " done."
	fi
} # }}}

forward_off()
{ # {{{
	echo -en "NAT: Disabling packet forwarding..."
	echo 0 > /proc/sys/net/ipv4/ip_forward
	echo " done."
} # }}}

# clear status of iptable chains
remove_chains()
{ # {{{

	for table in filter nat mangle; do
		$IPTABLES -t $table -F # clear all chains
		$IPTABLES -t $table -X # remove all chains
		$IPTABLES -t $table -Z # zero counts
	done

} # }}}

# DROP packages from nmap(1)
nmap_scan_filter()
{ # {{{

	echo -en "Turning on nmap scan filter "

	for chain in INPUT FORWARD; do
		#  Nie je nastaveny ziaden bit
		$IPTABLES_LOG	-A $chain   -p TCP --tcp-flags ALL NONE  $LOG_LIMIT "nmap scan $chain ALL NONE: "
		echo -en "."
		$IPTABLES		-A $chain   -p TCP --tcp-flags ALL NONE -j DROP 
		echo -en "."

		# dva odporujuuce si flagy su nastavene:
		for flags in   SYN,FIN   SYN,RST   FIN,RST   ; do
			$IPTABLES_LOG	-A $chain   -p TCP --tcp-flags $flags $flags $LOG_LIMIT "nmap scan $chain $flags: "
			echo -en "."
			$IPTABLES		-A $chain   -p TCP --tcp-flags $flags $flags -j DROP 
			echo -en "."
		done

		# je nastavene len $flags bez predpokladaneho ACK
		for flags in   FIN   PSH   URG   ; do
			$IPTABLES_LOG	-A $chain   -p TCP --tcp-flags ACK,$flags $flags $LOG_LIMIT "nmap scan $chain ACK,$flags: "
			echo -en "."
			$IPTABLES		-A $chain   -p TCP --tcp-flags ACK,$flags $flags -j DROP 
			echo -en "."
		done
	done
	
	echo " done."

} # }}}

# drop packets in state INVALID
invalid_packet_filter()
{ # {{{
	
	echo -en "Turning on INVALID packet filter "
	for chain in INPUT OUTPUT FORWARD; do
		$IPTABLES_LOG	-A $chain -m state --state INVALID $LOG_LIMIT "INVALID $chain: "
		echo -en "."
		$IPTABLES		-A $chain -m state --state INVALID -j DROP 
		echo -en "."
	done

	echo " done."

} # }}}

syn_flood()
{ # {{{
	$IPTABLES -N syn-flood
	$IPTABLES -A syn-flood -m limit --limit 1/s --limit-burst 4 -j RETURN
	$IPTABLES -A syn-flood -j DROP

	for iface in $INTERFACES; do
		$IPTABLES -A INPUT -i $iface -p TCP --syn -j syn-flood

		# packet is marked az NEW, but doesn't have SYN flag - drop it
		$IPTABLES -A INPUT -i $iface -p TCP ! --syn -m state --state NEW -j DROP
	done


} # }}}

anti_spoof_filter()
{ # {{{
	
	#   http://www.iana.com/assignments/ipv4-address-space

	if [ ! -z "$ANTISPOOF_IFACE" ]; then

		echo -en "Turning on antispoof filter for interfaces: "
		$IPTABLES -N spoof

		# Ochrana proti Spoogingu zo spatnej slucky
		$IPTABLES_LOG	-A spoof -s 127.0.0.0/8 $LOG_LIMIT "RESERVED:127.0.0.0/8 src" 
		$IPTABLES		-A spoof -s 127.0.0.0/8 -j DROP 
		$IPTABLES_LOG	-A spoof -d 127.0.0.0/8 $LOG_LIMIT "RESERVED:127.0.0.0/8 dest"
		$IPTABLES		-A spoof -d 127.0.0.0/8 -j DROP
		# Ochrana proti Spoofingu Internetu z adries urcenych pre lokalne siete 
		$IPTABLES_LOG	-A spoof -s 192.168.0.0/16 $LOG_LIMIT "RESERVED:192.168.0.0/16 src"
		$IPTABLES		-A spoof -s 192.168.0.0/16 -j DROP 		# RFC1918
		$IPTABLES_LOG	-A spoof -s 172.16.0.0/12 $LOG_LIMIT "RESERVED:172.16.0.0/12 src"
		$IPTABLES		-A spoof -s 172.16.0.0/12 -j DROP 		# RFC1918
		$IPTABLES_LOG	-A spoof -s 10.0.0.0/8  $LOG_LIMIT "RESERVED:10.0.0.0/8 src"
		$IPTABLES		-A spoof -s 10.0.0.0/8 -j DROP  # RFC1918 len pre sietovy interface do Internetu, kedze 10.0.0.0 je adresa LAN
		$IPTABLES_LOG	-A spoof -s 96.0.0.0/4 $LOG_LIMIT "RESERVED:96.0.0.0/4 src"
		$IPTABLES		-A spoof -s 96.0.0.0/4 -j DROP  			# IANA

		for iface in $ANTISPOOF_IFACE; do
			echo -en " $iface"
			$IPTABLES -A FORWARD -i $iface -j spoof
			$IPTABLES -A INPUT   -i $iface -j spoof
		done
		echo " done."
	fi
} # }}}

mangle_prerouting()
{ # {{{

	echo -en "Optimizing PREROUTING TOS: "
	# TOS flagy slouzi k optimalizaci datovych cest. Pro ssh, ftp a telnet
	# pozadujeme minimalni zpozdeni. Pro ftp-data zase maximalni propostnost
	$IPTABLES -t mangle -A PREROUTING -p TCP --sport ssh -j TOS --set-tos Minimize-Delay
	echo -en "."
	$IPTABLES -t mangle -A PREROUTING -p TCP --dport ssh -j TOS --set-tos Minimize-Delay
	echo -en "."
	$IPTABLES -t mangle -A PREROUTING -p TCP --sport ftp -j TOS --set-tos Minimize-Delay
	echo -en "."
	$IPTABLES -t mangle -A PREROUTING -p TCP --dport ftp -j TOS --set-tos Minimize-Delay
	echo -en "."
	$IPTABLES -t mangle -A PREROUTING -p TCP --dport telnet -j TOS --set-tos Minimize-Delay
	echo -en "."
	$IPTABLES -t mangle -A PREROUTING -p TCP --sport ftp-data -j TOS --set-tos Maximize-Throughput
	echo -en "."
	echo " done."

} # }}}

mangle_output()
{ # {{{

	echo -en "Optimizing OUTPUT TOS:"
	# TOS flagy slouzi k optimalizaci datovych cest. Pro ssh, ftp a telnet
	# pozadujeme minimalni zpozdeni. Pro ftp-data zase maximalni propostnost
	for iface in $INTERFACES; do
		echo -en " $iface";
		$IPTABLES -t mangle -A OUTPUT -o $iface -p TCP --sport ssh -j TOS --set-tos Minimize-Delay
		$IPTABLES -t mangle -A OUTPUT -o $iface -p TCP --dport ssh -j TOS --set-tos Minimize-Delay
		$IPTABLES -t mangle -A OUTPUT -o $iface -p TCP --sport ftp -j TOS --set-tos Minimize-Delay
		$IPTABLES -t mangle -A OUTPUT -o $iface -p TCP --dport ftp -j TOS --set-tos Minimize-Delay
		$IPTABLES -t mangle -A OUTPUT -o $iface -p TCP --dport telnet -j TOS --set-tos Minimize-Delay
		$IPTABLES -t mangle -A OUTPUT -o $iface -p TCP --sport ftp-data -j TOS --set-tos Maximize-Throughput
	done
	echo " done."

} # }}}

# Masquerade local subnet
masquerade()
{ # {{{
	if [ ! -z "$NAT_LAN_IFACE" ]; then
        echo -en "NAT: Enabling packet forwarding..."
        echo 1 > /proc/sys/net/ipv4/ip_forward
        echo " done."
		echo -en "NAT: Masquerading local subnet: $NAT_SUBNET_IFACE --> $NAT_LAN_IFACE"

		ip="`get_first_ip_addr IP_$NAT_SUBNET_IFACE`"
		netmask="Mask_$NAT_SUBNET_IFACE"
		localnet="$ip/${!netmask}"

		lan_ip="`get_first_ip_addr IP_$NAT_LAN_IFACE`"

		# alow packets from private subnet
		$IPTABLES -A FORWARD -s ! $localnet -i $NAT_SUBNET_IFACE -j DROP
		for client_ip in $NAT_CLIENT_DROP; do
			echo -en " !$client_ip";
			$IPTABLES -A FORWARD -s $client_ip -i $NAT_SUBNET_IFACE -j DROP
		done

		for redirect in $NAT_TCP_PORT_REDIRECT; do
			#eval `echo $redirect | $AWK -v FS=: '{ printf "remote_port=%s; local_port=%s;", $1, $2; }'`
			eval `echo $redirect | \
				$AWK -v FS=: '	(NF == 2) { remote_ip = "$lan_ip"; remote_port = $1; local_port = $2; } \
								(NF == 3) { remote_ip = $2;        remote_port = $1; local_port = $3; } \
								END { printf "remote_ip=%s; remote_port=%s; local_port=%s;", remote_ip, remote_port, local_port; }'`
			echo -en " $remote_port>>$remote_ip:$local_port(udp)"
			$IPTABLES -t nat -A PREROUTING -p TCP \
				-i ! $NAT_LAN_IFACE -d ! $lan_ip \
				--dport $remote_port -j REDIRECT --to-port $local_port
		done
		for redirect in $NAT_UDP_PORT_REDIRECT; do
			#eval `echo $redirect | $AWK -v FS=: '{ printf "remote_port=%s; local_port=%s;", $1, $2; }'`
			eval `echo $redirect | \
				$AWK -v FS=: '	(NF == 2) { dnat = "no"  ; remote_ip = "X"; remote_port = $1; local_port = $2; } \
								(NF == 3) { dnat = "yes" ; remote_ip = $2;  remote_port = $1; local_port = $3; } \
								END { printf "dnat=%s; remote_ip=%s; remote_port=%s; local_port=%s;", dnat, remote_ip, remote_port, local_port; }'`
			echo -en " $remote_port>>$remote_ip:$local_port(udp)"
			if [ "x$dnat" = "xyes" ]; then
				$IPTABLES -t nat -A PREROUTING -p UDP -i $NAT_SUBNET_IFACE -d ! $ip \
				--dport $local_port -j DNAT --to $remote_ip:$remote_port
				$IPTABLES -A FORWARD -p UDP -i $NAT_SUBNET_IFACE -d ! $ip --dport $local_port -j ACCEPT
			else
				$IPTABLES -t nat -A PREROUTING -p UDP \
					-i ! $NAT_LAN_IFACE -d ! $lan_ip \
					--dport $remote_port -j REDIRECT --to-port $local_port
			fi
		done

		#$IPTABLES -t nat -A POSTROUTING -s $localnet -o $NAT_LAN_IFACE -j MASQUERADE
		$IPTABLES -t nat -A POSTROUTING -o $NAT_LAN_IFACE -j MASQUERADE

		echo " done."

		# don't forward Miscrosoft protocols - NOT RFC compliant packets
		if [ ! -z "$NAT_FORWARD_MICROSOFT" ]; then
			if [ "x$NAT_FORWARD_MICROSOFT" = "xno" ]; then
				$IPTABLES -A FORWARD -p TCP ! --syn -m state --state NEW -j DROP

				for port in 69 135 445 1434 6667; do
					$IPTABLES -A FORWARD -p TCP --dport $port -j DROP
					$IPTABLES -A FORWARD -p UDP --dport $port -j DROP
				done
			fi
		fi

		if [ ! -z "$NAT_FORWARD_TCP_PORTS" ]; then
			echo -en "\tAccepting FORWARD TCP ports:"
			for port in $NAT_FORWARD_TCP_PORTS; do
				echo -en " $port"
				$IPTABLES -A FORWARD -p TCP --dport $port -m state --state NEW -j ACCEPT
			done
			echo " done."
		fi

		if [ ! -z "$NAT_FORWARD_UDP_PORTS" ]; then
			echo -en "\tAccepting FORWARD UDP ports:"
			for port in $NAT_FORWARD_UDP_PORTS; do
				echo -en " $port"
				$IPTABLES -A FORWARD -p UDP --dport $port -m state --state NEW -j ACCEPT
			done
			echo " done."
		fi

		echo -en "\tAccepting ICMP packets:"
		for type in $ACCEPT_ICMP_PACKETS; do
			echo -en " $type"
			$IPTABLES -A FORWARD -p ICMP --icmp-type $type -j ACCEPT
		done
		#$IPTABLES_LOG -A FORWARD -p ICMP -j LOG --log-prefix "FWD ICMP: "
		echo " done."

		# Port forwarding to local machines
		if [ ! -z "$NAT_TCP_PORT_FORWARD" ]; then
			echo -en "\tForwarding TCP ports to local machines:"
			for redirect in $NAT_TCP_PORT_FORWARD; do
				eval `echo $redirect | $AWK -v FS=: '{ printf "src_port=%s; local_machine=%s; dest_port=%s;", $1, $2, $3; }'`
				echo -en " $src_port -> $local_machine:$dest_port"
				$IPTABLES -t nat -A PREROUTING -p TCP -i $NAT_LAN_IFACE -d $lan_ip \
				--dport $src_port -j DNAT --to $local_machine:$dest_port
				$IPTABLES -A FORWARD -p TCP -i $NAT_LAN_IFACE -d $local_machine --dport $dest_port -j ACCEPT
			done
			echo " done."
		fi
		if [ ! -z "$NAT_UDP_PORT_FORWARD" ]; then
			echo -en "\tForwarding UDP ports to local machines:"
			for redirect in $NAT_UDP_PORT_FORWARD; do
				eval `echo $redirect | $AWK -v FS=: '{ printf "src_port=%s; local_machine=%s; dest_port=%s;", $1, $2, $3; }'`
				echo -en " $src_port -> $local_machine:$dest_port"
				$IPTABLES -t nat -A PREROUTING -p UDP -i $NAT_LAN_IFACE -d $lan_ip \
				--dport $src_port -j DNAT --to $local_machine:$dest_port
				$IPTABLES -A FORWARD -p UDP -i $NAT_LAN_IFACE -d $local_machine --dport $dest_port -j ACCEPT
			done
			echo " done."
		fi

		# Keep state of connections from private subnets
		$IPTABLES -A OUTPUT  -m state --state NEW -o $NAT_LAN_IFACE -j ACCEPT
		#$IPTABLES -A FORWARD -m state --state NEW -o $NAT_LAN_IFACE -j ACCEPT
		$IPTABLES -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT

		# hide NAT clients behind firewall: - set TTL
		# XXX: warning: this breaks traceroute !!!
		if [ ! "a$NAT_SET_TTL" = "ano" ]; then
			echo "NAT: clients hidden behind firewall - setting TTL to $NAT_SET_TTL"
			$IPTABLES -t mangle -A POSTROUTING -o $NAT_LAN_IFACE -j TTL --ttl-set $NAT_SET_TTL
		fi


	fi
} # }}}

log_new_connections()
{ # {{{
	if [ ! -z "$NAT_LOG_NEW_CONNECTIONS" ]; then
		if [ "x$NAT_LOG_NEW_CONNECTIONS" = "xyes" ]; then
			if [ "x$NAT_LOG_NEW_CONNECTIONS" = "xyes" ]; then
				NAT_LOG_NEW_CONNECTIONS="TCP UDP"
			fi
			echo -en "Logging new connections $NAT_LOG_NEW_CONNECTIONS:"
			for proto in $NAT_LOG_NEW_CONNECTIONS; do
				$IPTABLES_LOG -A INPUT   -m state --state NEW -p $proto -j LOG --log-prefix "IN  connection: "
				$IPTABLES_LOG -A OUTPUT  -m state --state NEW -p $proto -j LOG --log-prefix "OUT connection: "
				$IPTABLES_LOG -A FORWARD -m state --state NEW -p $proto -j LOG --log-prefix "FWD connection: "
			done
			echo " done."
		fi
	fi
} # }}}

drop_output()
{ # {{{

	for iface in $INTERFACES; do
		drop_output_tcp="${iface}_DROP_OUTPUT_TCP"
		DROP_OUTPUT_TCP="${!drop_output_tcp}"
		drop_output_udp="${iface}_DROP_OUTPUT_UDP"
		DROP_OUTPUT_UDP="${!drop_output_udp}"

		if [ ! -z "$DROP_OUTPUT_TCP" ]; then
			echo -en "$iface: Dropping outgoing packets from ports:"
			for port in $DROP_OUTPUT_TCP; do
				echo -en " $port"
				$IPTABLES -A FORWARD -p TCP --sport $port -o $iface -j DROP
				$IPTABLES -A OUTPUT  -p TCP --sport $port -o $iface -j DROP
			done
			echo " done."
		fi

		if [ ! -z "$DROP_OUTPUT_UDP" ]; then
			echo -en "$iface: Dropping outgoing packets from ports:"
			for port in $DROP_OUTPUT_UDP; do
				echo -en " $port"
				$IPTABLES -A FORWARD -p UDP --sport $port -o $iface -j DROP
				$IPTABLES -A OUTPUT  -p UDP --sport $port -o $iface -j DROP
			done
			echo " done."
		fi
	done

} # }}}

bann_ip_adresses()
{ # {{{
	#
	# This feature has been developed for following reason:
	# UbiCrawler spam our website with many requests (they are duplicit requests of the same page!)
	# And this web robot doesn't accept HTTP META tags (http://www.robotstxt.org/wc/faq.html#extension)
	#
	# Bann them too!
	#
	#IP address is: 146.48.97.11 146.48.97.13
	# User Agent: "UbiCrawler/v0.4beta (http://ubi.iit.cnr.it/projects/ubicrawler/)"
	#
	if [ ! -z "$BANNED_IP" ]; then
		echo -en "Dropping ALL packets from IP:"
		for banned_ip in $BANNED_IP; do
			echo -en " $banned_ip"
			$IPTABLES -A INPUT		-s $banned_ip -j DROP
			$IPTABLES -A FORWARD	-s $banned_ip -j DROP
		done
		echo " done."
	fi
} # }}}

allow_accept_all()
{ # {{{
	if [ ! -z "$IFACE_ACCEPT_ALL" ]; then
		echo -en "Accepting ALL packets on interfaces:"
		for iface in $IFACE_ACCEPT_ALL; do
			echo -en " $iface"
			$IPTABLES -A INPUT   -i $iface -j ACCEPT
			$IPTABLES -A FORWARD -i $iface -j ACCEPT
			$IPTABLES -A OUTPUT  -o $iface -j ACCEPT
		done
		echo " done."
	fi
} # }}}

allow_input()
{ # {{{

	if [ ! -z "$NAT_LAN_IFACE" ]; then
		for client_ip in $NAT_CLIENT_DROP; do
			echo -en " !$client_ip";
			$IPTABLES -A INPUT -s $client_ip -i $NAT_SUBNET_IFACE -j DROP
		done
	fi
	if [ ! -z "$ALL_DROP_INPUT_TCP" ]; then
		echo -en "Drop ALL INPUT TCP connections on ports:"
		for port in $ALL_DROP_INPUT_TCP; do
			for iface in $INTERFACES; do
				echo -en " $port($iface)"
				$IPTABLES -A INPUT -i $iface -p TCP --dport $port -j DROP
			done
		done
		echo " done."
	fi
	if [ ! -z "$ALL_DROP_INPUT_UDP" ]; then
		echo -en "Drop ALL INPUT UDP connections on ports:"
		for port in $ALL_DROP_INPUT_UDP; do
			for iface in $INTERFACES; do
				echo -en " $port($iface)"
				$IPTABLES -A INPUT -i $iface -p UDP --dport $port -j DROP
			done
		done
		echo " done."
	fi
	if [ ! -z "$ALL_ACCEPT_INPUT_TCP" ]; then
		echo -en "Accepting ALL INPUT TCP connections on ports:"
		for port in $ALL_ACCEPT_INPUT_TCP; do
			src_ip=""
			eval `echo $port | awk -v FS=: '/:/ { printf "src_ip=\"%s\"; port=\"%s\";", $1, $2; }'`
			for iface in $INTERFACES; do
				echo -en " $port($iface)"`[ ! -z $src_ip ] && echo "[$src_ip]"`
				IPS="IP_$iface";
				for ip in ${!IPS}; do
					if [ -z "$src_ip" ]; then
						$IPTABLES -A INPUT -i $iface -d $ip -p TCP --dport $port -j ACCEPT
					else
						$IPTABLES -A INPUT -i $iface -s $src_ip -d $ip -p TCP --dport $port -j ACCEPT
					fi
				done
			done
		done
		echo " done."
	fi
	if [ ! -z "$ALL_ACCEPT_INPUT_UDP" ]; then
		echo -en "Accepting ALL INPUT UDP connections on ports:"
		for port in $ALL_ACCEPT_INPUT_UDP; do
			src_ip=""
			eval `echo $port | awk -v FS=: '/:/ { printf "src_ip=\"%s\"; port=\"%s\";", $1, $2; }'`
			for iface in $INTERFACES; do
				echo -en " $port($iface)"`[ ! -z $src_ip ] && echo "[$src_ip]"`
				IPS="IP_$iface";
				for ip in ${!IPS}; do
					if [ -z "$src_ip" ]; then
						$IPTABLES -A INPUT -i $iface -d $ip -p UDP --dport $port -j ACCEPT
					else
						$IPTABLES -A INPUT -i $iface -s $src_ip -d $ip -p UDP --dport $port -j ACCEPT
					fi
				done
			done
		done
		echo " done."
	fi

	for iface in $INTERFACES; do
		IPS="IP_$iface";

		redirect_tcp="${iface}_REDIRECT_TCP"
		REDIRECT_TCP="${!redirect_tcp}"
		redirect_udp="${iface}_REDIRECT_UDP"
		REDIRECT_UDP="${!redirect_udp}"

		accept_input_tcp="${iface}_ACCEPT_INPUT_TCP"
		ACCEPT_INPUT_TCP="${!accept_input_tcp}"
		accept_input_udp="${iface}_ACCEPT_INPUT_UDP"
		ACCEPT_INPUT_UDP="${!accept_input_udp}"

		if [ ! -z "$REDIRECT_TCP" ]; then
			echo -en "$iface: redirecting TCP connections:"
			ip="`get_first_ip_addr IP_$iface`";
			for redirect in $REDIRECT_TCP; do
				eval `echo $redirect | \
					$AWK -v FS=: '	(NF == 2) { remote_ip = "0.0.0.0/0"; from_port = $1; to_port = $2; } \
									(NF == 3) { remote_ip = $1;          from_port = $2; to_port = $3; } \
									END { printf "remote_ip=%s; from_port=%s; to_port=%s;", remote_ip, from_port, to_port; }'`
				echo -en " $remote_ip:$from_port->$to_port"
				$IPTABLES -t nat -A PREROUTING -p TCP -i $iface -s $remote_ip -d $ip --dport $from_port -j REDIRECT --to-port $to_port
			done
			echo " done."
		fi

		if [ ! -z "$REDIRECT_UDP" ]; then
			echo -en "$iface: redirecting UDP connections:"
			ip="`get_first_ip_addr IP_$iface`";
			for redirect in $REDIRECT_UDP; do
				eval `echo $redirect | \
					$AWK -v FS=: '	(NF == 2) { remote_ip = "0.0.0.0/0"; from_port = $1; to_port = $2; } \
									(NF == 3) { remote_ip = $1;          from_port = $2; to_port = $3; } \
									END { printf "remote_ip=%s; from_port=%s; to_port=%s;", remote_ip, from_port, to_port; }'`
				echo -en " $remote_ip:$from_port->$to_port"
				$IPTABLES -t nat -A PREROUTING -p UDP -i $iface -s $remote_ip -d $ip --dport $from_port -j REDIRECT --to-port $to_port
			done
			echo " done."
		fi

		if [ ! -z "$ACCEPT_INPUT_TCP" ]; then
			echo -en "$iface: Accepting INPUT TCP connections on ports:"
			for port in $ACCEPT_INPUT_TCP; do
				src_ip=""
				eval `echo $port | awk -v FS=: '/:/ { printf "src_ip=\"%s\"; port=\"%s\";", $1, $2; }'`
				echo -en " $port"`[ ! -z $src_ip ] && echo "[$src_ip]"`
				for ip in ${!IPS}; do
					if [ -z $src_ip ]; then
						$IPTABLES -A INPUT -i $iface -d $ip -p TCP --dport $port -j ACCEPT
					else
						$IPTABLES -A INPUT -i $iface -s $src_ip -d $ip -p TCP --dport $port -j ACCEPT
					fi
				done
			done
			echo " done."
		fi

		if [ ! -z "$ACCEPT_INPUT_UDP" ]; then
			echo -en "$iface: Accepting INPUT UDP connections on ports:"
			for port in $ACCEPT_INPUT_UDP; do
				src_ip=""
				eval `echo $port | awk -v FS=: '/:/ { printf "src_ip=\"%s\"; port=\"%s\";", $1, $2; }'`
				echo -en " $port"`[ ! -z $src_ip ] && echo "[$src_ip]"`
				#$IPTABLES -A INPUT -i $iface -d ${!INET_IP} -p UDP --dport $port -j ACCEPT
				#$IPTABLES -A INPUT -i $iface --source 192.168.1.0/16 -p UDP --dport $port -j ACCEPT
				for ip in ${!IPS}; do
					if [ -z $src_ip ]; then
						$IPTABLES -A INPUT -i $iface -d $ip -p UDP --dport $port -j ACCEPT
					else
						$IPTABLES -A INPUT -i $iface -s $src_ip -d $ip -p UDP --dport $port -j ACCEPT
					fi
				done
			done
			echo " done."
		fi
	done

	# Enable outgoing TRACEROUTE requests (required e.g. by Skype, http://www.skype.com)
	if [ ! -z "$TRACEROUTE_IFACE" ]; then
		ip="`get_first_ip_addr IP_$ANTISPOOF_IFACE`";
		echo -en "Accepting traceroute:"

		$IPTABLES -A OUTPUT -o $ANTISPOOF_IFACE -p UDP \
			--sport $TRACEROUTE_SRC_PORTS --dport $TRACEROUTE_DEST_PORTS \
			-s $ip -d $ANYWHERE -j ACCEPT

		for iface in $TRACEROUTE_IFACE; do
			$IPTABLES -A FORWARD -p UDP -i $iface --sport $TRACEROUTE_SRC_PORTS \
				--dport $TRACEROUTE_DEST_PORTS -j ACCEPT
		done
		echo " done."
	fi

} # }}}

# ACCEPT all packets from our IP address
allow_output()
{ # {{{

	# Povolíme odchozí pakety, které mají naše IP adresy
	echo -en "Accepting OUTPUT packets from"
	for iface in $INTERFACES; do
		IPS="IP_$iface";
		for ip in ${!IPS}; do
			echo -en " $ip($iface)"
			$IPTABLES -A OUTPUT -o $iface -s $ip -j ACCEPT
		done
	done;
	echo " done.";

} # }}}

allow_icmp()
{ # {{{

	echo -en "Accepting ICMP packets:"
	# Službu AUTH není dobré filtrovat pomocí DROP, protože to může
	# vést k prodlevám při navazování některých spojení. Proto jej
	# sice zamítneme, ale vygenerujeme korektní ICMP chybovou zprávu
	$IPTABLES -A INPUT -p TCP --dport 113 -j REJECT --reject-with tcp-reset #AUTH server

	# accept only allowed ICMP packets
	for type in $ACCEPT_ICMP_PACKETS; do
		echo -en " $type"
		for iface in $INTERFACES; do
			IPS="IP_$iface";
			for ip in ${!IPS}; do
				$IPTABLES -A INPUT -i $iface -d $ip -p ICMP --icmp-type $type -j ACCEPT
			done
		done
	done
	#$IPTABLES_LOG -A INPUT  -p ICMP -j LOG --log-prefix "IN  ICMP: "
	#$IPTABLES_LOG -A OUTPUT -p ICMP -j LOG --log-prefix "OUT ICMP: "
	echo " done."

} # }}}

log_input_drop()
{ # {{{

	if [ ! "x$LOGGING" = "xoff" ]; then
		prefix="input drop: "
		echo "Input drop is logged with prefix '$prefix'"
		$IPTABLES_LOG -A INPUT $LOG_LIMIT "$prefix"
	fi

} # }}}

log_output_drop()
{ # {{{

	if [ ! "x$LOGGING" = "xoff" ]; then
		prefix="output drop: "
		echo "Output drop is logged with prefix '$prefix'"
		$IPTABLES_LOG -A OUTPUT $LOG_LIMIT "$prefix"
	fi

} # }}}

log_forward_drop()
{ # {{{

	if [ ! "x$LOGGING" = "xoff" ]; then
		prefix="forward drop: "
		echo "Forward drop is logged with prefix '$prefix'"
		$IPTABLES_LOG -A FORWARD $LOG_LIMIT "$prefix"
	fi

} # }}}

configure_special_rules()
{ # {{{

	echo -en "Loading special rules: "
	##
	## for DSL from Slovanet (Slovak DSL provider) and DSL modem DLINK DSL-360T you must add following rule for proper ssh connect to your machine
	##
	# echo -en "slovanet "
	# $IPTABLES -t mangle -A OUTPUT -s 0/0 -j DSCP --set-dscp 0

	echo " done.";

} # }}}

do_ip_accounting()
{ # {{{

	if [ ! "x$DO_LOCAL_IP_ACCOUNTING" = "xno" ]; then
		if [ ! -z "$NAT_LAN_IFACE" ]; then
			IPACCT_NAME="ZORBCOUNT"
			IPACCT_IN_NAME="ZORBCOUNTIN"
			IPACCT_OUT_NAME="ZORBCOUNTOUT"
			$IPTABLES -N $IPACCT_NAME		# whole network
			$IPTABLES -N $IPACCT_IN_NAME	# download: from server to client
			$IPTABLES -A $IPACCT_IN_NAME
			$IPTABLES -N $IPACCT_OUT_NAME	# upload: from client to server
			$IPTABLES -A $IPACCT_OUT_NAME

			ip="`get_first_ip_addr IP_$NAT_SUBNET_IFACE`";
			netmask="Mask_$NAT_SUBNET_IFACE"
			localnet="$ip/${!netmask}"

			$IPTABLES -I INPUT  -i $NAT_LAN_IFACE -j $IPACCT_IN_NAME
			$IPTABLES -I OUTPUT -o $NAT_LAN_IFACE -j $IPACCT_OUT_NAME

			$IPTABLES -I FORWARD -s $localnet -o $NAT_LAN_IFACE -j $IPACCT_NAME
			$IPTABLES -I FORWARD -d $localnet -i $NAT_LAN_IFACE -j $IPACCT_NAME

			for client_ip in $IP_ACCT_CLIENTS; do
				$IPTABLES -A $IPACCT_NAME -s $client_ip
				$IPTABLES -A $IPACCT_NAME -d $client_ip
			done

			if [ ! "x$DO_LOCAL_IP_ACCOUNTING" = "xno" ]; then
				accountig_ports=`echo "$NAT_TCP_PORT_REDIRECT " | $AWK -v RS=' ' -v FS=:  '{ print $2; }' | sort -u -r -g `
				for port in $accountig_ports; do
					$IPTABLES -I INPUT -i $NAT_SUBNET_IFACE -p TCP --dport $port -j $IPACCT_NAME
					$IPTABLES -I INPUT -i $NAT_SUBNET_IFACE -p UDP --dport $port -j $IPACCT_NAME
					$IPTABLES -I OUTPUT -o $NAT_SUBNET_IFACE -p TCP --sport $port -j $IPACCT_NAME
					$IPTABLES -I OUTPUT -o $NAT_SUBNET_IFACE -p UDP --sport $port -j $IPACCT_NAME
				done
			fi

			$IPTABLES -A $IPACCT_NAME -s $localnet
			$IPTABLES -A $IPACCT_NAME -d $localnet
			
		fi
	fi

} # }}}

accept_related()
{ # {{{

	echo -en "Accepting ESTABLISHED, RELATED packets for IP:"
	for iface in $INTERFACES; do
		IPS="IP_$iface";
		for ip in ${!IPS}; do
			echo -en " $ip($iface)"
		done
		$IPTABLES -A INPUT	-m state --state ESTABLISHED,RELATED -j ACCEPT
		$IPTABLES -A OUTPUT	-m state --state ESTABLISHED,RELATED -j ACCEPT
	done
	echo " done."

} # }}}

accept_loopback()
{ # {{{
	
	# Loopback není radno omezovat
	echo -en "Accepting loopback:"
	$IPTABLES -A INPUT  -i $LO_IFACE -j ACCEPT
	$IPTABLES -A OUTPUT -o $LO_IFACE -j ACCEPT
	echo " done."

} # }}}

# Parse output from ifconfig: - tested on Linux and FreeBSD
# http://platon.sk/cvs/cvs.php/scripts/shell/firewall/ifconfig-parse.sh
parse_ifconfig()
{ # {{{
	# Parse output from ifconfig:
	parsed_interfaces=`$IFCONFIG | \
		$PERL -e '
my $iface_count = 0;
my $iface;
my (%ip6, %scope6, %bcast, %mask, %hwaddr, %ipcount);

while (my $line = <STDIN>) {
	chomp $line;
	if ($line =~ m/^([a-z0-9:]+)\s+.*?([a-z0-9:]+)\s*$/i) { # Linux interface
		$iface	= $1;
		my $iface_hwaddr = $2;
		$iface	= [ $iface =~ m/^([a-z0-9]+)/i ]->[0]; # convert "eth0:0" --> "eth0"
		$ipcount{$iface}++;
		$hwaddr{$iface} = $iface_hwaddr;
		$iface_count++;
	}
	elsif ($line =~ m/^[ \t]+inet addr:/) { # Linux IP address
		die unless defined $iface;
		my @fields = split(/[\s:]+/, $line);
		push @{$ip{$iface}}, $fields[3];
		$bcast{$iface} = $fields[5]	|| ""; # invalid for loopback interface lo, but we don t need this
		$mask{$iface} = $fields[7]	|| $fields[5]; # for loopback interface lo
	}
	elsif($line =~ m/^[ \t]+inet6 addr:/) { # Linux IPv6 address
		die unless defined $iface;
		my @fields = split(/\s+/, $line);
		push @{$ip6{$iface}}, $fields[3];
		$scope6{$iface} = [ $fields[4] =~ m/Scope:(.*)$/i ]->[0];
	}

}

map { printf "IP_%s=\"%s\";			export IP_%s;\n",		$_, join(" ", @{$ip{$_}}),	$_; } keys %ip;
map { printf "IFACE_6_%s=\"%s\";	export IFACE_6_%s;\n",	$_, join(" ", @{$ip6{$_}}),	$_; } keys %ip6;
map { printf "SCOPE_6_%s=\"%s\";	export SCOPE_6_%s;\n",	$_, $scope6{$_},	$_; } keys %scope6;
map { printf "Bcast_%s=\"%s\";		export Bcast_%s;\n",	$_, $bcast{$_},	$_; } keys %bcast;
map { printf "Mask_%s=\"%s\";		export Mask_%s;\n",		$_, $mask{$_},	$_; } keys %mask;
map { printf "HWaddr_%s=\"%s\";		export HWaddr_%s;\n",	$_, $hwaddr{$_},	$_; } keys %hwaddr;
map { printf "IPcount_%s=\"%s\";	export IPcount_%s;\n",	$_, $ipcount{$_},	$_; } keys %ipcount;
printf "interfaces=\"%s\"; 	export interfaces;\n", join(" ", keys %ip);
	'`
	eval "$parsed_interfaces";

	parsed_routes=`$PERL -e '
	$\ = "\n";
	open(FILE, "/proc/net/route") or die "Can not open /proc/net/route: $!";
	my @columns = split(/\s+/, <FILE>);
	while (my $line = <FILE>) {
		my $iface;
		my @vals = split(/\s+/, $line);
		foreach my $key (@columns) {
			$iface->{$key} = shift @vals;
		}
		
		foreach my $key (qw( Gateway Destination )) {
			print "${key}_$iface->{Iface}=",
				qw("), hex2ip($iface->{$key}), qw("),
				"; export ${key}_$iface->{Iface};";
		}
		foreach my $key (qw( Flags MTU Metric Window IRTT )) {
			print "${key}_$iface->{Iface}=",
				qw("), $iface->{$key}, qw("),
				"; export ${key}_$iface->{Iface};";
		}
	}
	close(FILE);


	sub hex2ip
	{ # {{{
		my ($str) = @_;
		my @block;

		my $hex = uc($str);

		while (length($hex)) {
			my $x = ord(substr($hex, 0, 1));
			my $y = ord(substr($hex, 1, 1));

			$x = $x > 64 ? $x - 55 : $x - 48;
			$y = $y > 64 ? $y - 55 : $y - 48;

			push @block, 16 * $x + $y;
			$hex = substr($hex, 2);
		}

		return join(".", reverse @block);

	} # }}}
	'`
	eval "$parsed_routes";

	# Now we have defined variables like this:
	# IFACE_eth0 HWaddr_eth0 IP_eth0 Bcast_eth0 Mask_eth0
	# IFACE_lo   HWaddr_lo   IP_lo   Bcast_lo   Mask_lo
	# interfaces

} # }}}


parse_ifconfig
print_iface_status

#
# Split interfaces into 2 groups:
#
# $INTERFACES_ACCEPT_ALL - interfaces withouth restrictions
#
# $INTERFACES - all interfaces withouth loopback
#               and devices without restrictions (e.g. tun0 tun1 tap0 ...)
#
# list of all interfaces is in $interfaces variable
#
INTERFACES=""
INTERFACES_ACCEPT_ALL=""
regexp='^\('`echo $IFACE_ACCEPT_ALL | sed 's/ /\\\|/g; s/+/.*/g;'`'\)$'
for iface in $interfaces; do
	#if [ "o$iface" = "olo" ]; then continue; fi
	echo $iface | grep -q -e "$regexp"
	if [ $? = 0 ] || [ "o$iface" = "olo" ]; then # lo interface is always here
		INTERFACES_ACCEPT_ALL="$INTERFACES_ACCEPT_ALL $iface";
	else
		INTERFACES="$INTERFACES $iface";
	fi
done
INTERFACES_ACCEPT_ALL="$IFACE_ACCEPT_ALL"


case "$1" in
	start)
		echo -n "Starting $DESC: "
		# Inicialize modules
		#$DEPMOD -a
		load_modules
		load_cache
		set_default_policy
		remove_chains
		#
		# (un)commnet next lines as needed
		#
		bann_ip_adresses
		allow_accept_all
		nmap_scan_filter
		invalid_packet_filter
		anti_spoof_filter
		#syn_flood
		mangle_prerouting
		mangle_output
		accept_related
		log_new_connections
		drop_output
		allow_input
		allow_output
		allow_icmp
		accept_loopback
		masquerade
		log_input_drop
		log_output_drop
		log_forward_drop
		forward_on
		do_ip_accounting
		configure_special_rules
		$IPTABLES_SAVE -c > $CACHE_FILE
		;;
		
	stop)
		echo -n "Stopping $DESC: "
		set_default_policy
		remove_chains
		unload_modules
		forward_off
		accept_related
		;;

	really-off)
		echo -n "Stopping $DESC: removing ALL rules, all packets are dropped !!"
		set_default_policy
		remove_chains
		unload_modules
		forward_off
		;;

	status)
		print_iface_status; echo
		$IPTABLES -L -nv
		;;

	purge)
		find $DEFAULT_CACHE_DIR -type f -ls -exec rm -f {} \;
		;;

	*)
		echo "Usage: $0 {start|stop|really-off|status|purge}" >&2
		exit 1
		;;
esac

exit 0

# vim600: fdm=marker fdl=0 fdc=3