shorewall_code/Shorewall-common/lib.base

#!/bin/sh
#
# Shorewall 4.1 -- /usr/share/shorewall/lib.base
#
#     This program is under GPL [http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt]
#
#     (c) 1999,2000,2001,2002,2003,2004,2005,2006,2007 - Tom Eastep (teastep@shorewall.net)
#
#	Complete documentation is available at http://shorewall.net
#
#	This program is free software; you can redistribute it and/or modify
#	it under the terms of Version 2 of the GNU General Public License
#	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.
#
#	You should have received a copy of the GNU General Public License
#	along with this program; if not, write to the Free Software
#	Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
#
# This library contains the code common to all Shorewall components.
#
# - It is copied into the compiled script with the -e compiler flag is specified to
#   shorewall-shell.
# - It is loaded by /sbin/shorewall.
# - It is loaded by /usr/share/shorewall/firewall.
# - It is loaded by /usr/share/shorewall-shell/compiler.
# - It is released as part of Shorewall Lite where it is used by /sbin/shorewall-lite
#   and /usr/share/shorewall-lite/shorecap.
# - It is released as part of Shorewall Perl where it is copied into the compiled script
#   by the compiler.
#

SHOREWALL_LIBVERSION=40000
SHOREWALL_CAPVERSION=40100

[ -n "${VARDIR:=/var/lib/shorewall}" ]
[ -n "${SHAREDIR:=/usr/share/shorewall}" ]
[ -n "${CONFDIR:=/etc/shorewall}" ]
SHELLSHAREDIR=/usr/share/shorewall-shell
PERLSHAREDIR=/usr/share/shorewall-perl

#
# Message to stderr
#
error_message() # $* = Error Message
{
   echo "   $@" >&2
}

#
# Conditionally produce message
#
progress_message() # $* = Message
{
    local timestamp=

    if [ $VERBOSE -gt 1 ]; then
	[ -n "$TIMESTAMP" ] && timestamp="$(date +%H:%M:%S) "
	echo "${timestamp}$@"
    fi
}

progress_message2() # $* = Message
{
    local timestamp=

    if [ $VERBOSE -gt 0 ]; then
	[ -n "$TIMESTAMP" ] && timestamp="$(date +%H:%M:%S) "
	echo "${timestamp}$@"
    fi
}

progress_message3() # $* = Message
{
    local timestamp=

    if [ $VERBOSE -ge 0 ]; then
	[ -n "$TIMESTAMP" ] && timestamp="$(date +%H:%M:%S) "
	echo "${timestamp}$@"
    fi
}

#
# Split a colon-separated list into a space-separated list
#
split() {
    local ifs=$IFS
    IFS=:
    echo $*
    IFS=$ifs
}

#
# Search a list looking for a match -- returns zero if a match found
# 1 otherwise
#
list_search() # $1 = element to search for , $2-$n = list
{
    local e=$1

    while [ $# -gt 1 ]; do
	shift
	[ "x$e" = "x$1" ] && return 0
    done

    return 1
}

#
# Undo the effect of 'separate_list()'
#
combine_list()
{
    local f o=

    for f in $* ; do
        o="${o:+$o,}$f"
    done

    echo $o
}

#
# Suppress all output for a command
#
qt()
{
    "$@" >/dev/null 2>&1
}

#
# Determine if Shorewall is "running"
#
shorewall_is_started() {
    qt $IPTABLES -L shorewall -n
}

#
# Echos the fully-qualified name of the calling shell program
#
my_pathname() {
    cd $(dirname $0)
    echo $PWD/$(basename $0)
}

#
# Source a user exit file if it exists
#
run_user_exit() # $1 = file name
{
    local user_exit=$(find_file $1)

    if [ -f $user_exit ]; then
	progress_message "Processing $user_exit ..."
	. $user_exit
    fi
}

#
# Set a standard chain's policy
#
setpolicy() # $1 = name of chain, $2 = policy
{
    run_iptables -P $1 $2
}

#
# Set a standard chain to enable established and related connections
#
setcontinue() # $1 = name of chain
{
    run_iptables -A $1 -m state --state ESTABLISHED,RELATED -j ACCEPT
}

#
# Flush one of the NAT table chains
#
flushnat() # $1 = name of chain
{
    run_iptables -t nat -F $1
}

#
# Flush one of the Mangle table chains
#
flushmangle() # $1 = name of chain
{
    run_iptables -t mangle -F $1
}

#
# Flush and delete all user-defined chains in the filter table
#
deleteallchains() {
    run_iptables -F
    run_iptables -X
}

#
# Load a Kernel Module -- assumes that the variable 'moduledirectories' contains
#                         a space-separated list of directories to search for
#                         the module and that 'moduleloader' contains the
#                         module loader command.
#
loadmodule() # $1 = module name, $2 - * arguments
{
    local modulename=$1
    local modulefile
    local suffix

    if ! list_search $modulename $MODULES $DONT_LOAD ; then
	shift

	for suffix in $MODULE_SUFFIX ; do
	    for directory in $moduledirectories; do
		modulefile=$directory/${modulename}.${suffix}

		if [ -f $modulefile ]; then
		    case $moduleloader in
			insmod)
			    insmod $modulefile $*
			    ;;
			*)
			    modprobe $modulename $*
			    ;;
		    esac
		    break 2
		fi
	    done
	done
    fi
}

#
# Reload the Modules
#
reload_kernel_modules() {

    local save_modules_dir=$MODULESDIR
    local directory
    local moduledirectories=
    local moduleloader=modprobe

    if ! qt mywhich modprobe; then
	moduleloader=insmod
    fi

    [ -n "${MODULE_SUFFIX:=o gz ko o.gz ko.gz}" ]

    [ -z "$MODULESDIR" ] && MODULESDIR=/lib/modules/$(uname -r)/kernel/net/ipv4/netfilter:/lib/modules/$(uname -r)/kernel/net/netfilter
    MODULES=$(lsmod | cut -d ' ' -f1)

    for directory in $(split $MODULESDIR); do
	[ -d $directory ] && moduledirectories="$moduledirectories $directory"
    done

    [ -n "$moduledirectories" ] && while read command; do
	eval $command
    done

    MODULESDIR=$save_modules_dir
}

#
# Load kernel modules required for Shorewall
#
load_kernel_modules() # $1 = Yes, if we are to save moduleinfo in $VARDIR
{
    local save_modules_dir=$MODULESDIR
    local directory
    local moduledirectories=
    local moduleloader=modprobe
    local savemoduleinfo=${1:-Yes} # So old compiled scripts still work

    if ! qt mywhich modprobe; then
	moduleloader=insmod
    fi

    [ -n "${MODULE_SUFFIX:=o gz ko o.gz ko.gz}" ]

    [ -z "$MODULESDIR" ] && \
	MODULESDIR=/lib/modules/$(uname -r)/kernel/net/ipv4/netfilter:/lib/modules/$(uname -r)/kernel/net/netfilter

    for directory in $(split $MODULESDIR); do
	[ -d $directory ] && moduledirectories="$moduledirectories $directory"
    done

    modules=$(find_file modules)

    if [ -f $modules -a -n "$moduledirectories" ]; then
	MODULES=$(lsmod | cut -d ' ' -f1)
	progress_message "Loading Modules..."
	. $modules
	if [ $savemoduleinfo = Yes ]; then
	    [ -d ${VARDIR} ] || mkdir -p ${VARDIR}
	    echo MODULESDIR="$MODULESDIR" > ${VARDIR}/.modulesdir
	    cp -f $modules ${VARDIR}/.modules
	fi
    elif [ $savemoduleinfo = Yes ]; then
	[ -d ${VARDIR} ] || mkdir -p ${VARDIR}
	> ${VARDIR}/.modulesdir	
	> ${VARDIR}/.modules
    fi

    MODULESDIR=$save_modules_dir
}

#
# Call this function to assert mutual exclusion with Shorewall. If you invoke the
# /sbin/shorewall program while holding mutual exclusion, you should pass "nolock" as
# the first argument. Example "shorewall nolock refresh"
#
# This function uses the lockfile utility from procmail if it exists.
# Otherwise, it uses a somewhat race-prone algorithm to attempt to simulate the
# behavior of lockfile.
#
mutex_on()
{
    local try=0
    local lockf=${LOCKFILE:=${VARDIR}/lock}

    MUTEX_TIMEOUT=${MUTEX_TIMEOUT:-60}

    if [ $MUTEX_TIMEOUT -gt 0 ]; then

	[ -d ${VARDIR} ] || mkdir -p ${VARDIR}

	if qt mywhich lockfile; then
	    lockfile -${MUTEX_TIMEOUT} -r1 ${lockf}
	else
	    while [ -f ${lockf} -a ${try} -lt ${MUTEX_TIMEOUT} ] ; do
		sleep 1
		try=$((${try} + 1))
	    done

	    if  [ ${try} -lt ${MUTEX_TIMEOUT} ] ; then
	        # Create the lockfile
		echo $$ > ${lockf}
	    else
		echo "Giving up on lock file ${lockf}" >&2
	    fi
	fi
    fi
}

#
# Call this function to release mutual exclusion
#
mutex_off()
{
    rm -f ${LOCKFILE:=${VARDIR}/lock}
}

#
# Load an optional library
#
lib_load() # $1 = Name of the Library, $2 = Error Message heading if the library cannot be found
{
    local lib=${SHAREDIR}/lib.$1
    local loaded

    eval loaded=\$LIB_${1}_LOADED

    if [ -z "$loaded" ]; then
	[ -f $lib ] || lib=${SHELLSHAREDIR}/lib.$1
	
	if [ -f $lib ]; then
	    progress_message "Loading library $lib..."
	    . $lib
	    eval LIB_${1}_LOADED=Yes
	else
	    startup_error "$2 requires the Shorewall library $1 ($lib) which is not installed"
	fi
    fi
}

#
# Determine if an optional library is available
#
lib_avail() # $1 = Name of the Library
{
    [ -f ${SHAREDIR}/lib.$1 ]
}

#
#  Note: The following set of IP address manipulation functions have anomalous
#        behavior when the shell only supports 32-bit signed arithmetic and
#        the IP address is 128.0.0.0 or 128.0.0.1.
#

LEFTSHIFT='<<'

#
# Validate an IP address
#
valid_address() {
    local x y
    local ifs=$IFS

    IFS=.

    for x in $1; do
	case $x in
	    [0-9]|[0-9][0-9]|[1-2][0-9][0-9])
		[ $x -lt 256 ] || { IFS=$ifs; return 2; }
                ;;
	    *)
	        IFS=$ifs
		return 2
		;;
	esac
    done
    
    IFS=$ifs

    return 0
}

#
# Convert an IP address in dot quad format to an integer
#
decodeaddr() {
    local x
    local temp=0
    local ifs=$IFS

    IFS=.

    for x in $1; do
	temp=$(( $(( $temp $LEFTSHIFT 8 )) | $x ))
    done

    echo $temp

    IFS=$ifs
}

#
# convert an integer to dot quad format
#
encodeaddr() {
    addr=$1
    local x
    local y=$(($addr & 255))

    for x in 1 2 3 ; do
	addr=$(($addr >> 8))
	y=$(($addr & 255)).$y
    done

    echo $y
}

#
# Miserable Hack to work around broken BusyBox ash in OpenWRT
#
addr_comp() {
    test $(bc <<EOF
$1 > $2
EOF
) -eq 1

}

#
# Enumerate the members of an IP range -- When using a shell supporting only
# 32-bit signed arithmetic, the range cannot span 128.0.0.0.
#
# Comes in two flavors:
#
# ip_range() - produces a mimimal list of network/host addresses that spans
#              the range.
#
# ip_range_explicit() - explicitly enumerates the range.
#
ip_range() {
    local first last l x y z vlsm

    case $1 in
	!*)
	    #
	    # Let iptables complain if it's a range
	    #
	    echo $1
	    return
	    ;;
	[0-9]*.*.*.*-*.*.*.*)
            ;;
	*)
	    echo $1
	    return
	    ;;
    esac

    first=$(decodeaddr ${1%-*})
    last=$(decodeaddr ${1#*-})

    if addr_comp $first $last; then
	fatal_error "Invalid IP address range: $1"
    fi

    l=$(( $last + 1 ))

    while addr_comp $l $first; do
	vlsm=
	x=31
	y=2
	z=1

	while [ $(( $first % $y )) -eq 0 ] && addr_comp $l $(( $first + $y )) ; do
	    vlsm=/$x
	    x=$(( $x - 1 ))
	    z=$y
	    y=$(( $y * 2 ))
	done

	echo $(encodeaddr $first)$vlsm
	first=$(($first + $z))
    done
}

ip_range_explicit() {
    local first last

    case $1 in
    [0-9]*.*.*.*-*.*.*.*)
	;;
    *)
	echo $1
	return
	;;
    esac

    first=$(decodeaddr ${1%-*})
    last=$(decodeaddr ${1#*-})

    if addr_comp $first $last; then
	fatal_error "Invalid IP address range: $1"
    fi

    while ! addr_comp $first $last; do
	echo $(encodeaddr $first)
	first=$(($first + 1))
    done
}

#
# Netmask from CIDR
#
ip_netmask() {
    local vlsm=${1#*/}

    [ $vlsm -eq 0 ] && echo 0 || echo $(( -1 $LEFTSHIFT $(( 32 - $vlsm )) ))
}

#
# Network address from CIDR
#
ip_network() {
    local decodedaddr=$(decodeaddr ${1%/*})
    local netmask=$(ip_netmask $1)

    echo $(encodeaddr $(($decodedaddr & $netmask)))
}

#
# The following hack is supplied to compensate for the fact that many of
# the popular light-weight Bourne shell derivatives don't support XOR ("^").
#
ip_broadcast() {
    local x=$(( 32 - ${1#*/} ))

    [ $x -eq 32 ] && echo -1 || echo $(( $(( 1 $LEFTSHIFT $x )) - 1 ))
}

#
# Calculate broadcast address from CIDR
#
broadcastaddress() {
    local decodedaddr=$(decodeaddr ${1%/*})
    local netmask=$(ip_netmask $1)
    local broadcast=$(ip_broadcast $1)

    echo $(encodeaddr $(( $(($decodedaddr & $netmask)) | $broadcast )))
}

#
# Test for network membership
#
in_network() # $1 = IP address, $2 = CIDR network
{
    local netmask=$(ip_netmask $2)
    #
    # We compare the values as strings rather than integers to work around broken BusyBox ash on OpenWRT
    #
    test $(( $(decodeaddr $1) & $netmask)) = $(( $(decodeaddr ${2%/*}) & $netmask ))
}

#
# Netmask to VLSM
#
ip_vlsm() {
    local mask=$(decodeaddr $1)
    local vlsm=0
    local x=$(( 128 << 24 )) # 0x80000000

    while [ $(( $x & $mask )) -ne 0 ]; do
	[ $mask -eq $x ] && mask=0 || mask=$(( $mask $LEFTSHIFT 1 )) # Not all shells shift 0x80000000 left properly.
	vlsm=$(($vlsm + 1))
    done

    if [ $(( $mask & 2147483647 )) -ne 0 ]; then # 2147483647 = 0x7fffffff
	echo "Invalid net mask: $1" >&2
    else
	echo $vlsm
    fi
}


#
# Chain name base for an interface -- replace all periods with underscores in the passed name.
#                                     The result is echoed (less trailing "+").
#
chain_base() #$1 = interface
{
    local c=${1%%+}

    while true; do
	case $c in
	    @*)
               c=at_${c#@}
	       ;;               
	    *.*)
		c="${c%.*}_${c##*.}"
		;;
	    *-*)
		c="${c%-*}_${c##*-}"
		;;
	    *%*)
		c="${c%\%*}_${c##*%}"
		;;
	    *@*)
		c="${c%@*}_${c##*@}"
		;;
	    *)
		echo ${c:=common}
		return
		;;
	esac
    done
}

#
# Query NetFilter about the existence of a filter chain
#
chain_exists() # $1 = chain name
{
    qt $IPTABLES -L $1 -n
}

#
# Find the value 'dev' in the passed arguments then echo the next value
#

find_device() {
    while [ $# -gt 1 ]; do
	[ "x$1" = xdev ] && echo $2 && return
	shift
    done
}

#
# Find the value 'via' in the passed arguments then echo the next value
#

find_gateway() {
    while [ $# -gt 1 ]; do
	[ "x$1" = xvia ] && echo $2 && return
	shift
    done
}

#
# Find the value 'mtu' in the passed arguments then echo the next value
#

find_mtu() {
    while [ $# -gt 1 ]; do
	[ "x$1" = xmtu ] && echo $2 && return
	shift
    done
}

#
# Find the value 'peer' in the passed arguments then echo the next value up to
# "/"
#

find_peer() {
    while [ $# -gt 1 ]; do
	[ "x$1" = xpeer ] && echo ${2%/*} && return
	shift
    done
}

#
# Find the interfaces that have a route to the passed address - the default
# route is not used.
#

find_rt_interface() {
    ip route list | while read addr rest; do
	case $addr in
	    */*)
		in_network ${1%/*} $addr && echo $(find_device $rest)
		;;
	    default)
		;;
	    *)
		if [ "$addr" = "$1" -o "$addr/32" = "$1" ]; then
		    echo $(find_device $rest)
		fi
		;;
	esac
    done
}

#
# Try to find the gateway through an interface looking for 'nexthop'

find_nexthop() # $1 = interface
{
    echo $(find_gateway `ip route list | grep "[[:space:]]nexthop.* $1"`)
}

#
# Find the default route's interface
#
find_default_interface() {
    ip route list | while read first rest; do
	[ "$first" = default ] && echo $(find_device $rest) && return
    done
}

#
# Echo the name of the interface(s) that will be used to send to the
# passed address
#

find_interface_by_address() {
    local dev="$(find_rt_interface $1)"
    local first rest

    [ -z "$dev" ] && dev=$(find_default_interface)

    [ -n "$dev" ] && echo $dev
}

#
# Find the interface with the passed MAC address
#

find_interface_by_mac() {
    local mac=$1 first second rest dev

    ip link list | while read first second rest; do
	case $first in
	    *:)
                dev=$second
		;;
	    *)
	        if [ "$second" = $mac ]; then
		    echo ${dev%:}
		    return
		fi
	esac
    done
}

#
# Determine if Interface is up
#
interface_is_up() {
    [ -n "$(ip link list dev $1 2> /dev/null | grep -e '[<,]UP[,>]')" ]
}

#
# Find interface address--returns the first IP address assigned to the passed
# device
#
find_first_interface_address() # $1 = interface
{
    #
    # get the line of output containing the first IP address
    #
    addr=$(ip -f inet addr show $1 2> /dev/null | grep 'inet .* global' | head -n1)
    #
    # If there wasn't one, bail out now
    #
    [ -n "$addr" ] || fatal_error "Can't determine the IP address of $1"
    #
    # Strip off the trailing VLSM mask (or the peer IP in case of a P-t-P link)
    # along with everything else on the line
    #
    echo $addr | sed 's/\s*inet //;s/\/.*//;s/ peer.*//'
}

find_first_interface_address_if_any() # $1 = interface
{
    #
    # get the line of output containing the first IP address
    #
    addr=$(ip -f inet addr show $1 2> /dev/null | grep 'inet .* global' | head -n1)
    #
    # Strip off the trailing VLSM mask (or the peer IP in case of a P-t-P link)
    # along with everything else on the line
    #
    [ -n "$addr" ] && echo $addr | sed 's/\s*inet //;s/\/.*//;s/ peer.*//' || echo 0.0.0.0
}

#
# Determine if interface is usable from a Netfilter prespective
#
interface_is_usable() # $1 = interface
{
    interface_is_up $1 && [ "$(find_first_interface_address_if_any $1)" != 0.0.0.0 ]
}

#
# Find interface addresses--returns the set of addresses assigned to the passed
# device
#
find_interface_addresses() # $1 = interface
{
    ip -f inet addr show $1 2> /dev/null | grep inet\  | sed 's/\s*inet //;s/\/.*//;s/ peer.*//'
}

#
#  echo the list of networks routed out of a given interface
#
get_routed_networks() # $1 = interface name, $2-n = Fatal error message
{
    local address
    local rest

    ip route show dev $1 2> /dev/null |
	while read address rest; do
	    case "$address" in
		default)
		    if [ $# -gt 1 ]; then
			shift
			fatal_error "$@"
		    else
			echo "WARNING: default route ignored on interface $1" >&2
		    fi
		    ;;
		multicast|broadcast|prohibit|nat|throw|nexthop)
		    ;;
		*)
		    [ "$address" = "${address%/*}" ] && address="${address}/32"
		    echo $address
		    ;;
	    esac
        done
}

get_interface_bcasts() # $1 = interface
{
    ip -f inet addr show dev $1 2> /dev/null | grep 'inet.*brd' | sed 's/inet.*brd //; s/scope.*//;' | sort -u 
}

#
# Internal version of 'which'
#
mywhich() {
    local dir

    for dir in $(split $PATH); do
	if [ -x $dir/$1 ]; then
	    echo $dir/$1
	    return 0
	fi
    done

    return 2
}

#
# Set default config path
#
ensure_config_path() {
    local F=${SHAREDIR}/configpath
    if [ -z "$CONFIG_PATH" ]; then
	[ -f $F ] || { echo "   ERROR: $F does not exist"; exit 2; }
	. $F
    fi

    if [ -n "$SHOREWALL_DIR" ]; then
	[ "${CONFIG_PATH%%:*}" = "$SHOREWALL_DIR" ] || CONFIG_PATH=$SHOREWALL_DIR:$CONFIG_PATH
    fi
}

#
# Find a File -- For relative file name, look in each ${CONFIG_PATH} then ${CONFDIR}
#
find_file()
{
    local saveifs= directory

    case $1 in
	/*)
	    echo $1
	    ;;
	*)
	    for directory in $(split $CONFIG_PATH); do
		if [ -f $directory/$1 ]; then
		    echo $directory/$1
		    return
		fi
	    done

	    echo ${CONFDIR}/$1
	    ;;
    esac
}

#
# Get fully-qualified name of file
#
resolve_file() # $1 = file name
{
    local pwd=$PWD

    case $1 in
	/*)
	    echo $1
	    ;;
	.)
	    echo $pwd
	    ;;
	./*)
	    echo ${pwd}${1#.}
	    ;;
	..)
	    cd ..
	    echo $PWD
	    cd $pwd
	    ;;
	../*)
	    cd ..
	    resolve_file ${1#../}
	    cd $pwd
	    ;;
	*)
	    echo $pwd/$1
	    ;;
    esac
}

#
# Perform variable substitution on the passed argument and echo the result
#
expand() # $@ = contents of variable which may be the name of another variable
{
    eval echo \"$@\"
}

#
# Function for including one file into another
#
INCLUDE() {
    . $(find_file $(expand $@))
}

#
# Set the Shorewall state
#
set_state () # $1 = state
{
    echo "$1 ($(date))" > ${VARDIR}/state
}

#
# Determine which optional facilities are supported by iptables/netfilter
#
determine_capabilities() {
    qt $IPTABLES -t nat    -L -n && NAT_ENABLED=Yes    || NAT_ENABLED=
    qt $IPTABLES -t mangle -L -n && MANGLE_ENABLED=Yes || MANGLE_ENABLED=

    CONNTRACK_MATCH=
    MULTIPORT=
    XMULTIPORT=
    POLICY_MATCH=
    PHYSDEV_MATCH=
    PHYSDEV_BRIDGE=
    IPRANGE_MATCH=
    RECENT_MATCH=
    OWNER_MATCH=
    IPSET_MATCH=
    CONNMARK=
    XCONNMARK=
    CONNMARK_MATCH=
    XCONNMARK_MATCH=
    RAW_TABLE=
    IPP2P_MATCH=
    LENGTH_MATCH=
    CLASSIFY_TARGET=
    ENHANCED_REJECT=
    USEPKTTYPE=
    KLUDGEFREE=
    MARK=
    XMARK=
    MANGLE_FORWARD=
    COMMENTS=
    ADDRTYPE=
    TCPMSS_MATCH=
    HASHLIMIT_MATCH=
    NFQUEUE_TARGET=
    REALM_MATCH=

    chain=fooX$$

    [ -n "$IPTABLES" ] || IPTABLES=$(mywhich iptables)

    if [ -z "$IPTABLES" ]; then
	echo "   ERROR: No executable iptables binary can be found on your PATH" >&2
	exit 1
    fi

    qt $IPTABLES -F $chain
    qt $IPTABLES -X $chain
    if ! $IPTABLES -N $chain; then
	echo "   ERROR: The command \"$IPTABLES -N $chain\" failed" >&2
	exit 1
    fi

    qt $IPTABLES -A $chain -m conntrack --ctorigdst 192.168.1.1 -j ACCEPT && CONNTRACK_MATCH=Yes

    if qt $IPTABLES -A $chain -p tcp -m multiport --dports 21,22 -j ACCEPT; then
	MULTIPORT=Yes
	qt $IPTABLES -A $chain -p tcp -m multiport --sports 60 -m multiport --dports 99 -j ACCEPT && KLUDEFREE=Yes
    fi

    qt $IPTABLES -A $chain -p tcp -m multiport --dports 21:22 -j ACCEPT           && XMULTIPORT=Yes
    qt $IPTABLES -A $chain -m policy --pol ipsec --mode tunnel --dir in -j ACCEPT && POLICY_MATCH=Yes

    if qt $IPTABLES -A $chain -m physdev --physdev-out eth0 -j ACCEPT; then
	PHYSDEV_MATCH=Yes
	qt $IPTABLES -A $chain -m physdev --physdev-is-bridged --physdev-in eth0 --physdev-out eth0 -j ACCEPT && PHYSDEV_BRIDGE=Yes
	if [ -z "${KLUDGEFREE}" ]; then
	    qt $IPTABLES -A $chain -m physdev --physdev-in eth0 -m physdev --physdev-out eth0 -j ACCEPT && KLUDGEFREE=Yes
	fi
    fi

    if qt $IPTABLES -A $chain -m iprange --src-range 192.168.1.5-192.168.1.124 -j ACCEPT; then
	IPRANGE_MATCH=Yes
	if [ -z "${KLUDGEFREE}" ]; then
	    qt $IPTABLES -A $chain -m iprange --src-range 192.168.1.5-192.168.1.124 -m iprange --dst-range 192.168.1.5-192.168.1.124 -j ACCEPT && KLUDGEFREE=Yes
	fi
    fi

    qt $IPTABLES -A $chain -m recent --update -j ACCEPT     && RECENT_MATCH=Yes
    qt $IPTABLES -A $chain -m owner --uid-owner 0 -j ACCEPT && OWNER_MATCH=Yes

    if qt $IPTABLES -A $chain -m connmark --mark 2  -j ACCEPT; then
	CONNMARK_MATCH=Yes
	qt $IPTABLES -A $chain -m connmark --mark 2/0xFF -j ACCEPT && XCONNMARK_MATCH=Yes
    fi

    qt $IPTABLES -A $chain -p tcp -m ipp2p --ipp2p -j ACCEPT            && IPP2P_MATCH=Yes
    qt $IPTABLES -A $chain -m length --length 10:20 -j ACCEPT           && LENGTH_MATCH=Yes
    qt $IPTABLES -A $chain -j REJECT --reject-with icmp-host-prohibited && ENHANCED_REJECT=Yes

    qt $IPTABLES -A $chain -j ACCEPT -m comment --comment "This is a comment" && COMMENTS=Yes

    if [ -n "$MANGLE_ENABLED" ]; then
	qt $IPTABLES -t mangle -N $chain

	if qt $IPTABLES -t mangle -A $chain -j MARK --set-mark 1; then
	    MARK=Yes
	    qt $IPTABLES -t mangle -A $chain -j MARK --and-mark 0xFF && XMARK=Yes
	fi

	if qt $IPTABLES -t mangle -A $chain -j CONNMARK --save-mark; then
	    CONNMARK=Yes
	    qt $IPTABLES -t mangle -A $chain -j CONNMARK --save-mark --mask 0xFF && XCONNMARK=Yes
	fi

	qt $IPTABLES -t mangle -A $chain -j CLASSIFY --set-class 1:1 && CLASSIFY_TARGET=Yes
	qt $IPTABLES -t mangle -F $chain
	qt $IPTABLES -t mangle -X $chain
	qt $IPTABLES -t mangle -L FORWARD -n && MANGLE_FORWARD=Yes
    fi

    qt $IPTABLES -t raw	   -L -n && RAW_TABLE=Yes

    if qt mywhich ipset; then
	qt ipset -X $chain # Just in case something went wrong the last time

	if qt ipset -N $chain iphash ; then
	    if qt $IPTABLES -A $chain -m set --set $chain src -j ACCEPT; then
		qt $IPTABLES -D $chain -m set --set $chain src -j ACCEPT
		IPSET_MATCH=Yes
	    fi
	    qt ipset -X $chain
	fi
    fi

    qt $IPTABLES -A $chain -m pkttype --pkt-type broadcast -j ACCEPT && USEPKTTYPE=Yes
    qt $IPTABLES -A $chain -m addrtype --src-type BROADCAST -j ACCEPT && ADDRTYPE=Yes
    qt $IPTABLES -A $chain -p tcp --tcp-flags SYN,RST SYN -m tcpmss --mss 1000:1500 -j ACCEPT && TCPMSS_MATCH=Yes
    qt $IPTABLES -A $chain -m hashlimit --hashlimit 4 --hashlimit-burst 5 --hashlimit-name $chain --hashlimit-mode dstip -j ACCEPT && HASHLIMIT_MATCH=Yes
    qt $IPTABLES -A $chain -j NFQUEUE --queue-num 4 && NFQUEUE_TARGET=Yes

    qt $IPTABLES -A $chain -m realm --realm 4 && REALM_MATCH=Yes

    qt $IPTABLES -F $chain
    qt $IPTABLES -X $chain

    CAPVERSION=$SHOREWALL_CAPVERSION
}

report_capabilities() {
    report_capability() # $1 = Capability Description , $2 Capability Setting (if any)
    {
	local setting=

	[ "x$2" = "xYes" ] && setting="Available" || setting="Not available"

	echo "  " $1: $setting
    }

    if [ $VERBOSE -gt 1 ]; then
	echo "Shorewall has detected the following iptables/netfilter capabilities:"
	report_capability "NAT" $NAT_ENABLED
	report_capability "Packet Mangling" $MANGLE_ENABLED
	report_capability "Multi-port Match" $MULTIPORT
	[ -n "$MULTIPORT" ] && report_capability "Extended Multi-port Match" $XMULTIPORT
	report_capability "Connection Tracking Match" $CONNTRACK_MATCH
	report_capability "Packet Type Match" $USEPKTTYPE
	report_capability "Policy Match" $POLICY_MATCH
	report_capability "Physdev Match" $PHYSDEV_MATCH
	report_capability "Physdev-is-bridged Support" $PHYSDEV_BRIDGE
	report_capability "Packet length Match" $LENGTH_MATCH
	report_capability "IP range Match" $IPRANGE_MATCH
	report_capability "Recent Match" $RECENT_MATCH
	report_capability "Owner Match" $OWNER_MATCH
	report_capability "Ipset Match" $IPSET_MATCH
	report_capability "CONNMARK Target" $CONNMARK
	[ -n "$CONNMARK" ] && report_capability "Extended CONNMARK Target" $XCONNMARK
	report_capability "Connmark Match" $CONNMARK_MATCH
	[ -n "$CONNMARK_MATCH" ] && report_capability "Extended Connmark Match" $XCONNMARK_MATCH
	report_capability "Raw Table" $RAW_TABLE
	report_capability "IPP2P Match" $IPP2P_MATCH
	report_capability "CLASSIFY Target" $CLASSIFY_TARGET
	report_capability "Extended REJECT" $ENHANCED_REJECT
	report_capability "Repeat match" $KLUDGEFREE
	report_capability "MARK Target" $MARK
	[ -n "$MARK" ] && report_capability "Extended MARK Target" $XMARK
	report_capability "Mangle FORWARD Chain" $MANGLE_FORWARD
	report_capability "Comments" $COMMENTS
	report_capability "Address Type Match" $ADDRTYPE
	report_capability "TCPMSS Match" $TCPMSS_MATCH
	report_capability "Hashlimit Match" $HASHLIMIT_MATCH
	report_capability "NFQUEUE Target" $NFQUEUE_TARGET
	report_capability "Realm Match" $REALM_MATCH
    fi

    [ -n "$PKTTYPE" ] || USEPKTTYPE=

}

report_capabilities1() {
    report_capability1() # $1 = Capability
    {
	eval echo $1=\$$1
    }

    echo "#"
    echo "# Shorewall $VERSION detected the following iptables/netfilter capabilities - $(date)"
    echo "#"
    report_capability1 NAT_ENABLED
    report_capability1 MANGLE_ENABLED
    report_capability1 MULTIPORT
    report_capability1 XMULTIPORT
    report_capability1 CONNTRACK_MATCH
    report_capability1 USEPKTTYPE
    report_capability1 POLICY_MATCH
    report_capability1 PHYSDEV_MATCH
    report_capability1 PHYSDEV_BRIDGE
    report_capability1 LENGTH_MATCH
    report_capability1 IPRANGE_MATCH
    report_capability1 RECENT_MATCH
    report_capability1 OWNER_MATCH
    report_capability1 IPSET_MATCH
    report_capability1 CONNMARK
    report_capability1 XCONNMARK
    report_capability1 CONNMARK_MATCH
    report_capability1 XCONNMARK_MATCH
    report_capability1 RAW_TABLE
    report_capability1 IPP2P_MATCH
    report_capability1 CLASSIFY_TARGET
    report_capability1 ENHANCED_REJECT
    report_capability1 KLUDGEFREE
    report_capability1 MARK
    report_capability1 XMARK
    report_capability1 MANGLE_FORWARD
    report_capability1 COMMENTS
    report_capability1 ADDRTYPE
    report_capability1 TCPMSS_MATCH
    report_capability1 HASHLIMIT_MATCH
    report_capability1 NFQUEUE_TARGET
    report_capability1 REALM_MATCH
    
    echo CAPVERSION=$SHOREWALL_CAPVERSION
}

#
# Delete IP address
#
del_ip_addr() # $1 = address, $2 = interface
{
    [ $(find_first_interface_address_if_any $2) = $1 ] || qt ip addr del $1 dev $2
}

# Add IP Aliases
#
add_ip_aliases() # $* = List of addresses
{
    local addresses external interface inet cidr rest val arping=$(mywhich arping)

    address_details()
    {
	#
	# Folks feel uneasy if they don't see all of the same
	# decoration on these IP addresses that they see when their
	# distro's net config tool adds them. In an attempt to reduce
	# the anxiety level, we have the following code which sets
	# the VLSM and BRD from an existing address in the same networks
	#
	# Get all of the lines that contain inet addresses with broadcast
	#
	ip -f inet addr show $interface 2> /dev/null | grep 'inet.*brd' | while read inet cidr rest ; do
	    case $cidr in
		*/*)
		    if in_network $external $cidr; then
			echo "/${cidr#*/} brd $(broadcastaddress $cidr)"
			break
		    fi
		    ;;
	    esac
	done
    }

    do_one()
    {
	val=$(address_details)

	ip addr add ${external}${val} dev $interface $label
	[ -n "$arping" ] && qt $arping -U -c 2 -I $interface $external
	echo "$external $interface" >> $VARDIR/nat
	[ -n "$label" ] && label="with $label"
	progress_message "   IP Address $external added to interface $interface $label"
    }

    progress_message "Adding IP Addresses..."

    while [ $# -gt 0 ]; do
	external=$1
	interface=$2
	label=

	if [ "$interface" != "${interface%:*}" ]; then
	    label="${interface#*:}"
	    interface="${interface%:*}"
	    label="label $interface:$label"
	fi

	shift 2

	list_search $external $(find_interface_addresses $interface) || do_one
    done
}

detect_gateway() # $1 = interface
{
    local interface=$1
    #
    # First assume that this is some sort of point-to-point interface
    #
    gateway=$( find_peer $(ip addr list $interface ) )
    #
    # Maybe there's a default route through this gateway already
    #
    [ -n "$gateway" ] || gateway=$(find_gateway $(ip route list dev $interface))
    #
    # Last hope -- is there a load-balancing route through the interface?
    #
    [ -n "$gateway" ] || gateway=$(find_nexthop $interface)
    #
    # Be sure we found one
    #
    [ -n "$gateway" ] && echo $gateway
}

#
# Disable IPV6
#
disable_ipv6() {
    local foo="$(ip -f inet6 addr list 2> /dev/null)"

    if [ -n "$foo" ]; then
	if qt mywhich ip6tables; then
	    ip6tables -P FORWARD DROP
	    ip6tables -P INPUT DROP
	    ip6tables -P OUTPUT DROP
	    ip6tables -F
	    ip6tables -X
	    ip6tables -A OUTPUT -o lo -j ACCEPT
	    ip6tables -A INPUT -i lo -j ACCEPT
	else
	    error_message "WARNING: DISABLE_IPV6=Yes in shorewall.conf but this system does not appear to have ip6tables"
	fi
    fi
}

# Function to truncate a string -- It uses 'cut -b -<n>'
# rather than ${v:first:last} because light-weight shells like ash and
# dash do not support that form of expansion.
#

truncate() # $1 = length
{
    cut -b -${1}
}

#
# Add a logging rule.
#
do_log_rule_limit() # $1 = log level, $2 = chain, $3 = display Chain $4 = disposition , $5 = rate limit $6=log tag $7=command $... = predicates for the rule
{
    local level=$1
    local chain=$2
    local displayChain=$3
    local disposition=$4
    local rulenum=
    local limit=
    local tag=
    local command=
    local prefix
    local base=$(chain_base $displayChain)
    local pf

    limit="${5:-$LOGLIMIT}" # Do this here rather than in the declaration above to appease /bin/ash.
    tag=${6:+$6 }
    command=${7:--A}

    shift 7

    if [ -n "$tag" -a -n "$LOGTAGONLY" ]; then
	displayChain=$tag
	tag=
    fi

    if [ -n "$LOGRULENUMBERS" ]; then
	#
	# Hack for broken printf on some lightweight shells
	#
	[ $(printf "%d" 1) = "1" ] && pf=printf || pf=$(mywhich printf)

	eval rulenum=\$${base}_logrules

	rulenum=${rulenum:-1}

	prefix="$($pf "$LOGFORMAT" $displayChain $rulenum $disposition)${tag}"

	rulenum=$(($rulenum + 1))
	eval ${base}_logrules=$rulenum
    else
	prefix="$(printf "$LOGFORMAT" $displayChain $disposition)${tag}"
    fi

    if [ ${#prefix} -gt 29 ]; then
	prefix="`echo "$prefix" | truncate 28` "
	error_message "WARNING: Log Prefix shortened to \"$prefix\""
    fi

    case $level in
	ULOG)
	    $IPTABLES $command $chain $@ $limit -j ULOG $LOGPARMS --ulog-prefix "$prefix"
	    ;;
	*)
	    $IPTABLES $command $chain $@ $limit -j LOG $LOGPARMS --log-level $level --log-prefix "$prefix"
	    ;;
    esac

    if [ $? -ne 0 ] ; then
	[ -z "$STOPPING" ] && { stop_firewall; exit 2; }
    fi
}

do_log_rule() # $1 = log level, $2 = chain, $3 = disposition , $... = predicates for the rule
{
    local level=$1
    local chain=$2
    local disposition=$3

    shift 3

    do_log_rule_limit $level $chain $chain $disposition "$LOGLIMIT" "" -A $@
}

delete_tc1()
{
    clear_one_tc() {
        tc qdisc del dev $1 root 2> /dev/null
        tc qdisc del dev $1 ingress 2> /dev/null

    }

    run_user_exit tcclear

    run_ip link list | \
    while read inx interface details; do
        case $inx in
            [0-9]*)
                clear_one_tc ${interface%:}
                ;;
            *)
                ;;
        esac
    done
}

#
# Detect a device's MTU -- echos the passed device's MTU
#
get_device_mtu() # $1 = device
{
    local output="$(ip link list dev $1 2> /dev/null)" # quotes required for /bin/ash

    if [ -n "$output" ]; then
	echo $(find_mtu $output)
    else
	echo 1500
    fi
}

#
# Version of the above that doesn't generate any output for MTU 1500.
# Generates 'mtu <mtu+>' otherwise, where <mtu+> is the device's MTU + 100
#
get_device_mtu1() # $1 = device
{
    local output="$(ip link list dev $1 2> /dev/null)" # quotes required for /bin/ash
    local mtu

    if [ -n "$output" ]; then
	mtu=$(find_mtu $output)
	if [ -n "$mtu" ]; then
	    [ $mtu = 1500 ] || echo mtu $(($mtu + 100))
	fi
    fi

}

#
# Undo changes to routing
#
undo_routing() {

    if [ -z "$NOROUTES"  ]; then
	#
	# Restore rt_tables database
	#
	if [ -f ${VARDIR}/rt_tables ]; then
	    [ -w /etc/iproute2/rt_table -a -z "$KEEP_RT_TABLES" ] && cp -f ${VARDIR}/rt_tables /etc/iproute2/ && progress_message "/etc/iproute2/rt_tables database restored"
	    rm -f ${VARDIR}/rt_tables
	fi
	#
	# Restore the rest of the routing table
	#
	if [ -f ${VARDIR}/undo_routing ]; then
	    . ${VARDIR}/undo_routing
	    progress_message "Shorewall-generated routing tables and routing rules removed"
	    rm -f ${VARDIR}/undo_routing
	fi
    fi

}

restore_default_route() {
    if [ -z "$NOROUTES" -a -f ${VARDIR}/default_route ]; then
	local default_route= route

	while read route ; do
	    case $route in
		default*)
		    if [ -n "$default_route" ]; then
			case "$default_route" in
			    *metric*)
		                #
		                # Don't restore a route with a metric -- we only replace the one with metric == 0
		                #
				qt ip route delete default metric 0 && \
				    progress_message "Default Route with metric 0 deleted"
				;;
			    *)
				qt ip route replace $default_route && \
				    progress_message "Default Route (${default_route# }) restored"
				;;
			esac

			break
		    fi

		    default_route="$default_route $route"
		    ;;
		*)
		    default_route="$default_route $route"
		    ;;
	    esac
	done < ${VARDIR}/default_route

	rm -f ${VARDIR}/default_route
    fi
}

#
# Determine how to do "echo -e"
#

find_echo() {
    local result

    result=$(echo "a\tb")
    [ ${#result} -eq 3 ] && { echo echo; return; }

    result=$(echo -e "a\tb")
    [ ${#result} -eq 3 ] && { echo "echo -e"; return; }

    result=$(which echo)
    [ -n "$result" ] && { echo "$result -e"; return; }

    echo echo 
}

# Determine which version of mktemp is present (if any) and set MKTEMP accortingly:
#
#     None - No mktemp
#     BSD  - BSD mktemp (Mandrake)
#     STD  - mktemp.org mktemp
#
find_mktemp() {
    local mktemp=`mywhich mktemp 2> /dev/null`

    if [ -n "$mktemp" ]; then
	if qt mktemp -V ; then
	    MKTEMP=STD
	else
	    MKTEMP=BSD
	fi
    else
	MKTEMP=None
    fi
}

#
# create a temporary file. If a directory name is passed, the file will be created in
# that directory. Otherwise, it will be created in a temporary directory.
#
mktempfile() {

    [ -z "$MKTEMP" ] && find_mktemp

    if [ $# -gt 0 ]; then
	case "$MKTEMP" in
	    BSD)
		mktemp $1/shorewall.XXXXXX
		;;
	    STD)
		mktemp -p $1 shorewall.XXXXXX
		;;
	    None)
		> $1/shorewall-$$ && echo $1/shorewall-$$
		;;
	    *)
		error_message "ERROR:Internal error in mktempfile"
		;;
	esac
    else
	case "$MKTEMP" in
	    BSD)
		mktemp /tmp/shorewall.XXXXXX
		;;
	    STD)
		mktemp -t shorewall.XXXXXX
		;;
	    None)
		rm -f /tmp/shorewall-$$
		> /tmp/shorewall-$$ && echo /tmp/shorewall-$$
		;;
	    *)
		error_message "ERROR:Internal error in mktempfile"
		;;
	esac
    fi
}