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shorewall_code/Shorewall/functions
2003-10-30 15:42:45 +00:00

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#!/bin/sh
#
# Shorewall 1.4 -- /usr/lib/shorewall/functions
#
# Suppress all output for a command
#
qt()
{
"$@" >/dev/null 2>&1
}
#
# Find a File -- Look first in $SHOREWALL_DIR then in /etc/shorewall
#
find_file()
{
if [ -n "$SHOREWALL_DIR" -a -f $SHOREWALL_DIR/$1 ]; then
echo $SHOREWALL_DIR/$1
else
echo /etc/shorewall/$1
fi
}
#
# Replace commas with spaces and echo the result
#
separate_list() {
local list
local part
local newlist
#
# There's been whining about us not catching embedded white space in
# comma-separated lists. This is an attempt to snag some of the cases.
#
# The 'terminator' function will be set by the 'firewall' script to
# either 'startup_error' or 'fatal_error' depending on the command and
# command phase
#
case "$@" in
*,|,*|*,,*|*[[:space:]]*)
[ -n "$terminator" ] && \
$terminator "Invalid comma-separated list \"$@\""
echo "Warning -- invalid comma-separated list \"$@\"" >&2
;;
esac
list="$@"
part="${list%%,*}"
newlist="$part"
while [ "x$part" != "x$list" ]; do
list="${list#*,}";
part="${list%%,*}";
newlist="$newlist $part";
done
echo "$newlist"
}
#
# Find the zones
#
find_zones() # $1 = name of the zone file
{
while read zone display comments; do
[ -n "$zone" ] && case "$zone" in
\#*)
;;
$FW|multi)
echo "Reserved zone name \"$zone\" in zones file ignored" >&2
;;
*)
echo $zone
;;
esac
done < $1
}
find_display() # $1 = zone, $2 = name of the zone file
{
grep ^$1 $2 | while read z display comments; do
[ "x$1" = "x$z" ] && echo $display
done
}
#
# This function assumes that the TMP_DIR variable is set and that
# its value named an existing directory.
#
determine_zones()
{
local zonefile=`find_file zones`
multi_display=Multi-zone
strip_file zones $zonefile
zones=`find_zones $TMP_DIR/zones`
zones=`echo $zones` # Remove extra trash
for zone in $zones; do
dsply=`find_display $zone $TMP_DIR/zones`
eval ${zone}_display=\$dsply
done
}
#
# The following functions may be used by apps that wish to ensure that
# the state of Shorewall isn't changing
#
# This function loads the STATEDIR variable (directory where Shorewall is to
# store state files). If your application supports alternate Shorewall
# configurations then the name of the alternate configuration directory should
# be in $SHOREWALL_DIR at the time of the call.
#
# If the shorewall.conf file does not exist, this function does not return
#
get_statedir()
{
MUTEX_TIMEOUT=
local config=`find_file shorewall.conf`
if [ -f $config ]; then
. $config
else
echo "/etc/shorewall/shorewall.conf does not exist!" >&2
exit 2
fi
[ -z "${STATEDIR}" ] && STATEDIR=/var/state/shorewall
}
#
# Call this function to assert MUTEX with Shorewall. If you invoke the
# /sbin/shorewall program while holding MUTEX, 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=$STATEDIR/lock
MUTEX_TIMEOUT=${MUTEX_TIMEOUT:-60}
if [ $MUTEX_TIMEOUT -gt 0 ]; then
[ -d $STATEDIR ] || mkdir -p $STATEDIR
if qt which lockfile; then
lockfile -${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 MUTEX
#
mutex_off()
{
rm -f $STATEDIR/lock
}
#
# Read a file and handle "INCLUDE" directives
#
read_file() # $1 = file name, $2 = nest count
{
local first rest
while read first rest; do
if [ "x$first" = "xINCLUDE" ]; then
if [ $2 -lt 4 ]; then
read_file `find_file ${rest%#*}` $(($2 + 1))
else
echo " WARNING: INCLUDE in $1 ignored (nested too deeply)" >&2
fi
else
echo "$first $rest"
fi
done < $1
}
#
# Function for including one file into another
#
INCLUDE() {
. `find_file $@`
}
#
# Strip comments and blank lines from a file and place the result in the
# temporary directory
#
strip_file() # $1 = Base Name of the file, $2 = Full Name of File (optional)
{
local fname
[ $# = 1 ] && fname=`find_file $1` || fname=$2
if [ -f $fname ]; then
read_file $fname 0 | cut -d'#' -f1 | grep -v '^[[:space:]]*$' > $TMP_DIR/$1
else
> $TMP_DIR/$1
fi
}
#
# Note: The following set of IP address manipulation functions have anomalous
# behavior when the shell only supports 32-bit signed arithmatic and
# the IP address is 128.0.0.0 or 128.0.0.1.
#
#
# So that emacs doesn't get lost, we use $LEFTSHIFT rather than <<
#
LEFTSHIFT='<<'
#
# Convert an IP address in dot quad format to an integer
#
decodeaddr() {
local x
local temp=0
local ifs=$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
}
#
# 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
[0-9]*.*.*.*-*.*.*.*)
;;
*)
echo $1
return
;;
esac
first=`decodeaddr ${1%-*}`
last=`decodeaddr ${1#*-}`
if [ $first -gt $last ]; then
fatal_error "Invalid IP address range: $1"
fi
l=$(( $last + 1 ))
while [ $first -le $last ]; do
vlsm=
x=31
y=2
z=1
while [ $(( $first % $y )) -eq 0 -a $(( $first + $y )) -le $l ]; do
vlsm=/$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 [ $first -gt $last ]; then
fatal_error "Invalid IP address range: $1"
fi
while [ $first -le $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 0 ] && 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 subnet membership
#
in_subnet() # $1 = IP address, $2 = CIDR network
{
local netmask=`ip_netmask $2`
test $(( `decodeaddr $1` & $netmask)) -eq $(( `decodeaddr ${2%/*}` & $netmask ))
}
#
# Netmask to VLSM
#
ip_vlsm() {
local mask=`decodeaddr $1`
local vlsm=0
local x=$(( 128 $LEFTSHIFT 24 ))
while [ $(( $x & $mask )) -ne 0 ]; do
[ $mask -eq $x ] && mask=0 || mask=$(( $mask $LEFTSHIFT 1 )) # Don't Ask...
vlsm=$(($vlsm + 1))
done
if [ $(( $mask & 2147483647)) -ne 0 ]; then
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 "+" and anything following).
#
chain_base() #$1 = interface
{
local c=${1%%+*}
while true; do
case $c in
*.*)
c="${c%.*}_${c##*.}"
;;
*-*)
c="${c%-*}_${c##*-}"
;;
*)
echo ${c:=common}
return
;;
esac
done
}
#
# Remove trailing digits from a name
#
strip_trailing_digits() {
echo $1 | sed s'/[0-9].*$//'
}
#
# Loosly Match the name of an interface
#
if_match() # $1 = Name in interfaces file - may end in "+"
# $2 = Name from routing table
{
local if_file=$1
local rt_table=$2
case $if_file in
*+)
test "`strip_trailing_digits $rt_table`" = "${if_file%+}"
;;
*)
test "$rt_table" = "$if_file"
;;
esac
}
#
# 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 interfaces that have a route to the passed address - the default
# route is not used.
#
find_rt_interface() {
ip route ls | while read addr rest; do
case $addr in
*/*)
in_subnet ${1%/*} $addr && echo `find_device $rest`
;;
default)
;;
*)
if [ "$addr" = "$1" -o "$addr/32" = "$1" ]; then
echo `find_device $rest`
fi
;;
esac
done
}
#
# Find the default route's interface
#
find_default_interface() {
ip route ls | while read first rest; do
[ "$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
}