shorewall_code/Shorewall-core/lib.common

#
# Shorewall 4.5 -- /usr/share/shorewall/lib.common.
#
#     This program is under GPL [http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt]
#
#     (c) 2010-2012 - 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.
#
# The purpose of this library is to hold those functions used by both the CLI and by the
# generated firewall scripts. To avoid versioning issues, it is copied into generated
# scripts rather than loaded at run-time.
#
#########################################################################################
#
# Conditionally produce message
#
progress_message() # $* = Message
{
    local timestamp
    timestamp=

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

    if [ $LOG_VERBOSITY -gt 1 ]; then
        timestamp="$(date +'%b %_d %T') "
        echo "${timestamp}$@" >> $STARTUP_LOG
    fi
}

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

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

    if [ $LOG_VERBOSITY -gt 0 ]; then
        timestamp="$(date +'%b %_d %T') "
        echo "${timestamp}$@" >> $STARTUP_LOG
    fi
}

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

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

    if [ $LOG_VERBOSITY -ge 0 ]; then
        timestamp="$(date +'%b %_d %T') "
        echo "${timestamp}$@" >> $STARTUP_LOG
    fi
}

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

#
# Generate a list of all network interfaces on the system
#
find_all_interfaces() {
    ${IP:-ip} link list | egrep '^[[:digit:]]+:' | cut -d ' ' -f2 | sed -r 's/(@.*)?:$//'
}

#
# Generate a list of all network interfaces on the system that have an ipv4 address
#
find_all_interfaces1() {
    ${IP:-ip} -$g_family addr list | egrep '^[[:digit:]]+:' | cut -d ' ' -f2 | sed -r 's/(@.*)?:$//'
}

#
# 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
}

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

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

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

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

#
# Determine if interface is usable from a Netfilter prespective
#
interface_is_usable() # $1 = interface
{
    [ "$1" = lo ] && return 0
    interface_is_up $1 && [ "$(find_first_interface_address_if_any $1)" != :: ] && run_isusable_exit $1
}

#
# Find interface addresses--returns the set of addresses assigned to the passed
# device
#
find_interface_addresses() # $1 = interface
{
    if [ $g_family -eq 4 ]; then
	$IP -f inet addr show $1 2> /dev/null | grep inet\  | sed 's/\s*inet //;s/\/.*//;s/ peer.*//'
    else
	$IP -f inet6 addr show $1 2> /dev/null | grep 'inet6 2' | sed 's/\s*inet6 //;s/\/.*//;s/ peer.*//'
    fi
}

#
#  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

    $IP -$g_family 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 $1" >&2
		    fi
		    ;;
		multicast|broadcast|prohibit|nat|throw|nexthop)
		    ;;
		[2-9]*)
		    [ "$address" = "${address%/*}" ] && address="${address}/128"
		    echo $address
		    ;;
		*)
		    if [ $g_family -eq 4 ]; then
			[ "$address" = "${address%/*}" ] && address="${address}/128"
			echo $address
		    fi
		    ;;
	    esac
        done
}

#
# Clear the current traffic shaping configuration
#

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

    }

    run_tcclear_exit

    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() # $1 = device
{
    local output
    output="$($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() # $1 = device
{
    local output
    output="$($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() {
    local undofiles
    local f

    if [ -z "$g_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 ${VARDIR}/rt_tables
	fi
	#
	# Restore the rest of the routing table
	#
	undofiles="$(ls ${VARDIR}/undo_*routing 2> /dev/null)"

	if [ -n "$undofiles" ]; then
	    for f in $undofiles; do
		. $f
	    done

	    rm -f $undofiles

            progress_message "Shorewall-generated routing tables and routing rules removed"
	fi
    fi

}

#
# Save the default route
#
save_default_route() {
    awk \
    'BEGIN        {defroute=0;};
     /^default /  {defroute=1; print; next};
     /nexthop/    {if (defroute == 1 ) {print ; next} };
                  { defroute=0; };'
}

#
# Restore the default route that was in place before the initial 'shorewall start'
#
replace_default_route() # $1 = USE_DEFAULT_RT
{
    #
    # default_route and result are inherited from the caller
    #
    if [ -n "$default_route" ]; then
	case "$default_route" in
	    *metric*)
	        #
	        # Don't restore a default route with a metric unless USE_DEFAULT_RT=Yes. Otherwise, we only replace the one with metric 0
	        #
		[ -n "$1" ] && qt $IP -$g_family route replace $default_route && progress_message "Default Route (${default_route# }) restored"
		default_route=
		;;
	    *)
		qt $IP -$g_family route replace $default_route && progress_message "Default Route (${default_route# }) restored"
		result=0
		default_route=
		;;
	esac
    fi
}

restore_default_route() # $1 = USE_DEFAULT_RT
{
    local result
    result=1

    if [ -z "$g_noroutes" -a -f ${VARDIR}/default_route ]; then
	local default_route
	default_route=
	local route

	while read route ; do
	    case $route in
		default*)
		    replace_default_route $1
		    default_route="$default_route $route"
		    ;;
		*)
		    default_route="$default_route $route"
		    ;;
	    esac
	done < ${VARDIR}/default_route

	replace_default_route $1
	
	if [ $result = 1 ]; then
	    #
	    # We didn't restore a default route with metric 0
	    #
	    if $IP -$g_family -o route list 2> /dev/null | fgrep default | fgrep -qv metric; then
	       #
	       # But we added a default route with metric 0
	       #
	       qt $IP -$g_family route del default metric 0 && progress_message "Default route with metric 0 deleted"
	    fi
	fi

	rm -f ${VARDIR}/default_route
    fi

    return $result
}

#
# Flush the conntrack table if $g_purge is non-empty
#
conditionally_flush_conntrack() {

    if [ -n "$g_purge" ]; then
	if [ -n $(mywhich conntrack) ]; then
            conntrack -f ipv$_family -F
	else
            error_message "WARNING: The '-p' option requires the conntrack utility which does not appear to be installed on this system"
	fi
    fi
}

#
# Issue a message and stop/restore the firewall
#
fatal_error()
{
    echo "   ERROR: $@" >&2

    if [ $LOG_VERBOSITY -ge 0 ]; then
        timestamp="$(date +'%_b %d %T') "
        echo "${timestamp}  ERROR: $@" >> $STARTUP_LOG
    fi

    stop_firewall
    [ -n "$TEMPFILE" ] && rm -f $TEMPFILE
    exit 2
}

#
# Issue a message and stop
#
startup_error() # $* = Error Message
{
    echo "   ERROR: $@: Firewall state not changed" >&2

    if [ $LOG_VERBOSITY -ge 0 ]; then
        timestamp="$(date +'%_b %d %T') "
        echo "${timestamp}  ERROR: $@" >> $STARTUP_LOG
    fi

    case $COMMAND in
        start)
	    logger -p kern.err "ERROR:$g_product start failed:Firewall state not changed"
	    ;;
	restart)
	    logger -p kern.err "ERROR:$g_product restart failed:Firewall state not changed"
	    ;;
	restore)
	    logger -p kern.err "ERROR:$g_product restore failed:Firewall state not changed"
	    ;;
    esac

    if [ $LOG_VERBOSITY -ge 0 ]; then
        timestamp="$(date +'%_b %d %T') "

	case $COMMAND in
	    start)
		echo "${timestamp}  ERROR:$g_product start failed:Firewall state not changed" >> $STARTUP_LOG
		;;
	    restart)
		echo "${timestamp}  ERROR:$g_product restart failed:Firewall state not changed" >> $STARTUP_LOG
		;;
	    restore)
		echo "${timestamp}  ERROR:$g_product restore failed:Firewall state not changed" >> $STARTUP_LOG
		;;
	esac
    fi

    kill $$
    exit 2
}

#
# Run iptables and if an error occurs, stop/restore the firewall
#
run_iptables()
{
    local status

    while [ 1 ]; do
	$g_tool $@
	status=$?
	[ $status -ne 4 ] && break
    done

    if [ $status -ne 0 ]; then
        error_message "ERROR: Command \"$g_tool $@\" Failed"
	stop_firewall
        exit 2
    fi
}

#
# Run iptables retrying exit status 4
#
do_iptables()
{
    local status

    while [ 1 ]; do
	$g_tool $@
	status=$?
	[ $status -ne 4 ] && return $status;
    done
}

#
# Run iptables and if an error occurs, stop/restore the firewall
#
run_ip()
{
    if ! $IP -$g_family $@; then
	error_message "ERROR: Command \"$IP -$g_family $@\" Failed"
	stop_firewall
	exit 2
    fi
}

#
# Run tc and if an error occurs, stop/restore the firewall
#
run_tc() {
    if ! $TC $@ ; then
	error_message "ERROR: Command \"$TC $@\" Failed"
	stop_firewall
	exit 2
    fi
}

#
# Get the Shorewall version of the passed script
#
get_script_version() { # $1 = script
    local temp
    local version
    local ifs
    local digits
    local verbosity

    verbosity="$VERBOSITY"
    VERBOSITY=0

    temp=$( $SHOREWALL_SHELL $1 version | sed 's/-.*//' )

    if [ $? -ne 0 ]; then
	version=0
    else
	ifs=$IFS
	IFS=.
	temp=$(echo $temp)
	IFS=$ifs
	digits=0

	for temp in $temp; do
	    version=${version}$(printf '%02d' $temp)
	    digits=$(($digits + 1))
	    [ $digits -eq 3 ] && break
	done
    fi

    echo $version

    VERBOSITY="$verbosity"
}

#
# Do required exports or create the required option string and run the passed script using
# $SHOREWALL_SHELL
#
run_it() {
    local script
    local options
    local version

    export VARDIR

    script=$1
    shift

    version=$(get_script_version $script)

    if [ $version -lt 040408 ]; then
	#
	# Old script that doesn't understand 4.4.8 script options
	#
	export RESTOREFILE
	export VERBOSITY
	export NOROUTES=$g_noroutes
	export PURGE=$g_purge
	export TIMESTAMP=$g_timestamp
	export RECOVERING=$g_recovering

	case "$g_program" in
	    *-lite)
		#
		# Shorewall Lite
		#
		export LOGFORMAT
		export IPTABLES
		;;
	esac
    else
	#
	# 4.4.8 or later -- no additional exports required
	#
	if [ x$1 = xtrace -o x$1 = xdebug ]; then
	    options="$1 -"
	    shift;
	else
	    options='-'
	fi

	[ -n "$g_noroutes" ]   && options=${options}n
	[ -n "$g_timestamp" ]  && options=${options}t
	[ -n "$g_purge" ]      && options=${options}p
	[ -n "$g_recovering" ] && options=${options}r

	options="${options}V $VERBOSITY"

	[ -n "$RESTOREFILE" ] && options="${options} -R $RESTOREFILE"
    fi

    $SHOREWALL_SHELL $script $options $@
}

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

#
# Undo the effect of 'split()'
#
join()
{
    local f
    local o
    o=

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

    echo $o
}

#
# Return the number of elements in a list
#
list_count() # $* = list
{
    return $#
}

#
# Split a colon-separated list into a space-separated list
#
split() {
    local ifs
    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
    e=$1

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

    return 1
}

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

#
# Suppress all output and input - mainly for preventing leaked file descriptors
# to avoid SELinux denials
#
qtnoin()
{
    "$@" </dev/null >/dev/null 2>&1
}

qt1()
{
    local status

    while [ 1 ]; do
	"$@" </dev/null >/dev/null 2>&1
	status=$?
	[ $status -ne 4 ] && return $status
    done
}

#
# Determine if Shorewall[6] is "running"
#
product_is_started() {
    qt1 $g_tool -L shorewall -n
}

shorewall_is_started() {
    qt1 $IPTABLES -L shorewall -n
}

shorewall6_is_started() {
    qt1 $IP6TABLES -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() # $1 = file name
{
    local user_exit
    user_exit=$(find_file $1)

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

#
# 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
    modulename=$1
    local modulefile
    local suffix

    if [ -d /sys/module/ ]; then
	if ! list_search $modulename $DONT_LOAD; then
	    if [ ! -d /sys/module/$modulename ]; 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
	fi
    elif ! list_search $modulename $DONT_LOAD $MODULES; 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
    save_modules_dir=$MODULESDIR
    local directory
    local moduledirectories
    moduledirectories=
    local moduleloader
    moduleloader=modprobe
    local uname

    if ! qt mywhich modprobe; then
	moduleloader=insmod
    fi

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

    [ -z "$MODULESDIR" ] && \
	uname=$(uname -r) && \
	MODULESDIR=/lib/modules/$uname/kernel/net/ipv${g_family}/netfilter:/lib/modules/$uname/kernel/net/netfilter:/lib/modules/$uname/kernel/net/sched:/lib/modules/$uname/extra:/lib/modules/$uname/extra/ipset

    [ -d /sys/module/ ] || 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 $VARDIR
{
    local save_modules_dir
    save_modules_dir=$MODULESDIR
    local directory
    local moduledirectories
    moduledirectories=
    local moduleloader
    moduleloader=modprobe
    local savemoduleinfo
    savemoduleinfo=${1:-Yes} # So old compiled scripts still work
    local uname

    if ! qt mywhich modprobe; then
	moduleloader=insmod
    fi

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

    [ -z "$MODULESDIR" ] && \
	uname=$(uname -r) && \
	MODULESDIR=/lib/modules/$uname/kernel/net/ipv${g_family}/netfilter:/lib/modules/$uname/kernel/net/netfilter:/lib/modules/$uname/kernel/net/sched:/lib/modules/$uname/extra:/lib/modules/$uname/extra/ipset

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

    [ -n "$LOAD_HELPERS_ONLY" ] && modules=$(find_file helpers) || modules=$(find_file modules)

    if [ -f $modules -a -n "$moduledirectories" ]; then
	[ -d /sys/module/ ] || 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
}

#
#  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='<<'

#
# Convert an IP address in dot quad format to an integer
#
decodeaddr() {
    local x
    local temp
    temp=0
    local ifs
    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=$1
    local x
    local y
    y=$(($addr & 255))

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

    echo $y
}

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

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

#
# Network address from CIDR
#
ip_network() {
    local decodedaddr
    decodedaddr=$(decodeaddr ${1%/*})
    local netmask
    netmask=$(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
    x=$(( 32 - ${1#*/} ))

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

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

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

#
# Test for network membership
#
in_network() # $1 = IP address, $2 = CIDR network
{
    local netmask
    netmask=$(ip_netmask $2)
    #
    # Use string comparison to work around a broken BusyBox ash in OpenWRT
    #
    test $(( $(decodeaddr $1) & $netmask)) = $(( $(decodeaddr ${2%/*}) & $netmask ))
}

#
# Query NetFilter about the existence of a filter chain
#
chain_exists() # $1 = chain name
{
    qt1 $g_tool -L $1 -n
}

#
# Find the interface with the passed MAC address
#

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

#
# Find interface address--returns the first IP address assigned to the passed
# device
#
find_first_interface_address() # $1 = interface
{
    if [ $g_family -eq 4 ]; then
	#
	# get the line of output containing the first IP address
	#
	addr=$(${IP:-ip} -$g_family addr show $1 2> /dev/null | grep 'inet .* global' | head -n1)
	#
	# If there wasn't one, bail out now
	#
	[ -n "$addr" ] || startup_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 $addr | sed 's/\s*inet //;s/\/.*//;s/ peer.*//'
    else
	#
	# get the line of output containing the first IP address
	#
	addr=$(${IP:-ip} -f inet6 addr show dev $1 2> /dev/null | fgrep 'inet6 ' | fgrep -v 'scope link' | head -n1)
	#
	# If there wasn't one, bail out now
	#
	[ -n "$addr" ] || startup_error "Can't determine the IPv6 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*inet6 //;s/\/.*//;s/ peer.*//'
    fi
}

find_first_interface_address_if_any() # $1 = interface
{
    if [ $g_family -eq 4 ]; then
	#
	# get the line of output containing the first IP address
	#
	addr=$(${IP:-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 $addr | sed 's/\s*inet //;s/\/.*//;s/ peer.*//' || echo 0.0.0.0
    else
	#
	# get the line of output containing the first IP address
	#
	addr=$(${IP:-ip} -f inet6 addr show dev $1 2> /dev/null | fgrep 'inet6 ' | fgrep -v 'scope link' | head -n1)
	#
	# Strip off the trailing VLSM mask (or the peer IP in case of a P-t-P link)
	# along with everything else on the line
	#
	[ -n "$addr" ] && echo $addr | sed 's/\s*inet6 //;s/\/.*//;s/ peer.*//' || echo ::
    fi
}

#
# 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
}

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

#
# Set the Shorewall state
#
set_state () # $1 = state
{
    if [ $# -gt 1 ]; then
	echo "$1 ($(date)) from $2" > ${VARDIR}/state
    else
	echo "$1 ($(date))" > ${VARDIR}/state
    fi
}

#
# 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 $@))
}

# 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}
}