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<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>Shorewall-perl</title><link rel="stylesheet" href="html.css" type="text/css" /><meta name="generator" content="DocBook XSL Stylesheets V1.73.2" /></head><body><div class="article" lang="en" xml:lang="en"><div class="titlepage"><div><div><h2 class="title"><a id="id257527"></a>Shorewall-perl</h2></div><div><div class="authorgroup"><div class="author"><h3 class="author"><span class="firstname">Tom</span> <span class="surname">Eastep</span></h3></div></div></div><div><p class="copyright">Copyright © 2007 Thomas M. Eastep</p></div><div><div class="legalnotice"><a id="id292634"></a><p>Permission is granted to copy, distribute and/or modify this
document under the terms of the GNU Free Documentation License, Version
1.2 or any later version published by the Free Software Foundation; with
no Invariant Sections, with no Front-Cover, and with no Back-Cover
Texts. A copy of the license is included in the section entitled
“<span class="quote"><a class="ulink" href="GnuCopyright.htm" target="_self">GNU Free Documentation
License</a></span>”.</p></div></div><div><p class="pubdate">2008/12/15</p></div></div><hr /></div><div class="toc"><p><b>Table of Contents</b></p><dl><dt><span class="section"><a href="#What">Shorewall-perl - What is it?</a></span></dt><dt><span class="section"><a href="#DownSide">Shorewall-perl - The down side</a></span></dt><dd><dl><dt><span class="section"><a href="#Incompatibilities">Incompatibilities</a></span></dt><dt><span class="section"><a href="#PerlDep">Dependence on Perl</a></span></dt></dl></dd><dt><span class="section"><a href="#Prerequisites">Shorewall-perl - Prerequisites</a></span></dt><dt><span class="section"><a href="#Install">Shorewall-perl - Installation</a></span></dt><dt><span class="section"><a href="#Using">Using Shorewall-perl</a></span></dt><dt><span class="section"><a href="#Modules">The Shorewall Perl Modules</a></span></dt><dd><dl><dt><span class="section"><a href="#compiler.pl">/usr/share/shorewall-perl/compiler.pl</a></span></dt><dt><span class="section"><a href="#Compiler">Shorewall::Compiler</a></span></dt><dd><dl><dt><span class="section"><a href="#Compiler-4.0">Shorewall 4.0</a></span></dt><dt><span class="section"><a href="#id302969">Shorewall 4.2 and Later</a></span></dt></dl></dd><dt><span class="section"><a href="#Chains">Shorewall::Chains</a></span></dt><dt><span class="section"><a href="#Config">Shorewall::Config</a></span></dt></dl></dd></dl></div><div class="section" lang="en" xml:lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="What"></a>Shorewall-perl - What is it?</h2></div></div></div><p>Shorewall-perl is a companion product to Shorewall.</p><p>Shorewall-perl contains a re-implementation of the Shorewall
compiler written in Perl. The advantages of using Shorewall-perl over
Shorewall-shell (the shell-based compiler included in earlier Shorewall
3.x releases) are:</p><div class="itemizedlist"><ul type="disc"><li><p>The Shorewall-perl compiler is much faster.</p></li><li><p>The script generated by the compiler uses
<span class="command"><strong>iptables-restore</strong></span> to instantiate the Netfilter
configuration. So it runs much faster than the script generated by the
Shorewall-shell compiler.</p></li><li><p>The Shorewall-perl compiler does more thorough checking of the
configuration than the Shorewall-shell compiler does.</p></li><li><p>The error messages produced by the compiler are better, more
consistent and always include the file name and line number where the
error was detected.</p></li><li><p>Going forward, the Shorewall-perl compiler will get all
enhancements; the Shorewall-shell compiler will only get those
enhancements that are easy to retrofit.</p></li></ul></div></div><div class="section" lang="en" xml:lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="DownSide"></a>Shorewall-perl - The down side</h2></div></div></div><p>While there are advantages to using Shorewall-perl, there are also
disadvantages.</p><div class="section" lang="en" xml:lang="en"><div class="titlepage"><div><div><h3 class="title"><a id="Incompatibilities"></a>Incompatibilities</h3></div></div></div><p>There are a number of incompatibilities between the Shorewall-perl
compiler and the earlier one.</p><div class="orderedlist"><ol type="1"><li><p>The Perl-based compiler requires the following capabilities in
your kernel and iptables.</p><div class="itemizedlist"><ul type="disc"><li><p>addrtype match (Restriction relaxed in Shorewall-perl
4.0.1)</p></li><li><p>multiport match (will not be relaxed)</p></li></ul></div><p>These capabilities are in current distributions.</p></li><li><p>Now that Netfilter has features to deal reasonably with port
lists, I see no reason to duplicate those features in Shorewall. The
Shorewall-shell compiler goes to great pain (in some cases) to break
very long port lists ( > 15 where port ranges in lists count as
two ports) into individual rules. In the new compiler, I'm avoiding
the ugliness required to do that. The new compiler just generates an
error if your list is too long. It will also produce an error if you
insert a port range into a port list and you don't have extended
multiport support.</p></li><li><p>BRIDGING=Yes is not supported. The kernel code necessary to
support this option was removed in Linux kernel 2.6.20. <a class="ulink" href="bridge-Shorewall-perl.html" target="_self">Alternative bridge support</a>
is provided by Shorewall-perl.</p></li><li><p>The BROADCAST column in the interfaces file is essentially
unused if your kernel/iptables has Address Type Match support. If
that support is present and you enter anything in this column but
'-' or 'detect', you will receive a warning.</p></li><li><p>The 'refresh' command is now similar to restart with the
exceptions that:</p><div class="itemizedlist"><ul type="disc"><li><p>The command fails if Shorewall is not running.</p></li><li><p>A directory name cannot be specified in the
command.</p></li><li><p>The refresh command does not alter the Netfilter
configuration except for the static blacklist.</p></li></ul></div></li><li><p>With the shell-based compiler, extension scripts were copied
into the compiled script and executed at run-time. In many cases,
this approach doesn't work with Shorewall Perl because (almost) the
entire rule set is built by the compiler. As a result,
Shorewall-perl runs some extension scripts at compile-time rather
than at run-time. Because the compiler is written in Perl, your
extension scripts from earlier versions will no longer work.</p><p>The following table summarizes when the various extension
scripts are run:</p><div class="informaltable"><table border="1"><colgroup><col /><col /><col /></colgroup><tbody><tr><td><span class="bold"><strong>Compile-time (Must be written
in Perl)</strong></span></td><td><span class="bold"><strong>Run-time</strong></span></td><td><span class="bold"><strong>Eliminated</strong></span></td></tr><tr><td>initdone</td><td>clear</td><td>continue</td></tr><tr><td>maclog</td><td>initdone</td><td> </td></tr><tr><td>Per-chain (including those associated with
actions)</td><td>start</td><td> </td></tr><tr><td> </td><td>started</td><td> </td></tr><tr><td> </td><td>stop</td><td> </td></tr><tr><td> </td><td>stopped</td><td> </td></tr><tr><td> </td><td>tcclear</td><td> </td></tr></tbody></table></div><p>Compile-time extension scripts are executed using the Perl
'eval `cat <file>`' mechanism. Be sure that each script
returns a 'true' value; otherwise, the compiler will assume that the
script failed and will abort the compilation.</p><p>When a script is invoked, the <span class="bold"><strong>$chainref</strong></span> scalar variable will usually hold a
reference to a chain table entry.</p><table class="simplelist" border="0" summary="Simple list"><tr><td><span class="bold"><strong>$chainref->{name}</strong></span>
contains the name of the chain</td></tr><tr><td><span class="bold"><strong>$chainref->{table}</strong></span>
holds the table name</td></tr></table><p>To add a rule to the chain:</p><table class="simplelist" border="0" summary="Simple list"><tr><td>add_rule $chainref,
<em class="replaceable"><code>the-rule</code></em></td></tr></table><p>Where</p><table class="simplelist" border="0" summary="Simple list"><tr><td><em class="replaceable"><code>the rule</code></em> is a scalar argument
holding the rule text. Do not include "-A
<em class="replaceable"><code>chain-name</code></em>"</td></tr></table><p>Example:</p><table class="simplelist" border="0" summary="Simple list"><tr><td>add_rule $chainref, '-j ACCEPT';</td></tr></table><p>To insert a rule into the chain:</p><table class="simplelist" border="0" summary="Simple list"><tr><td>insert_rule $chainref, <em class="replaceable"><code>rulenum</code></em>,
<em class="replaceable"><code>the-rule</code></em></td></tr></table><p>The log_rule_limit function works like it does in the shell
compiler with three exceptions:</p><div class="itemizedlist"><ul type="disc"><li><p>You pass the chain reference rather than the name of the
chain.</p></li><li><p>The commands are 'add' and 'insert' rather than '-A' and
'-I'.</p></li><li><p>There is only a single "pass as-is to iptables" argument
(so you must quote that part</p></li></ul></div><p>Example:</p><pre class="programlisting"> log_rule_limit
'info' ,
$chainref ,
$chainref->{name},
'DROP' ,
'', #Limit
'' , #Log tag
'add'
'-p tcp '; </pre><p>Here is an example of an actual initdone script used with
Shorewall 3.4:</p><pre class="programlisting">run_iptables -t mangle -I PREROUTING -p esp -j MARK --set-mark 0x50
run_iptables -t filter -I INPUT -p udp --dport 1701 -m mark --mark 0x50 -j ACCEPT
run_iptables -t filter -I OUTPUT -p udp --sport 1701 -j ACCEPT
</pre><p>Here is the corresponding script used with
Shorewall-perl:</p><pre class="programlisting">use Shorewall::Chains;
insert_rule $mangle_table->{PREROUTING}, 1, "-p esp -j MARK --set-mark 0x50";
insert_rule $filter_table->{INPUT}, 1, "-p udp --dport 1701 -m mark --mark 0x50 -j ACCEPT";
insert_rule $filter_table->{OUTPUT}, 1, "-p udp --sport 1701 -j ACCEPT";
1;</pre><p>The initdone script is unique because the $chainref variable
is not set before the script is called. The above script illustrates
how the $mangle_table, $filter_table, and $nat_table references can
be used to add or insert rules in arbitrary chains.</p></li><li><p>The <code class="filename">/etc/shorewall/tos</code> file now has
zone-independent SOURCE and DEST columns as do all other files
except the rules and policy files.</p><p>The SOURCE column may be one of the following:</p><table class="simplelist" border="0" summary="Simple list"><tr><td>[<span class="command"><strong>all</strong></span>:]<<em class="replaceable"><code>address</code></em>>[,...]</td></tr><tr><td>[<span class="command"><strong>all</strong></span>:]<<em class="replaceable"><code>interface</code></em>>[:<<em class="replaceable"><code>address</code></em>>[,...]]</td></tr><tr><td><span class="command"><strong>$FW</strong></span>[:<<em class="replaceable"><code>address</code></em>>[,...]]</td></tr></table><p>The DEST column may be one of the following:</p><table class="simplelist" border="0" summary="Simple list"><tr><td>[<span class="command"><strong>all</strong></span>:]<<em class="replaceable"><code>address</code></em>>[,...]</td></tr><tr><td>[<span class="command"><strong>all</strong></span>:]<<em class="replaceable"><code>interface</code></em>>[:<<em class="replaceable"><code>address</code></em>>[,...]]</td></tr></table><p>This is a permanent change. The old zone-based rules have
never worked right and this is a good time to replace them. I've
tried to make the new syntax cover the most common cases without
requiring change to existing files. In particular, it will handle
the tos file released with Shorewall 1.4 and earlier.</p></li><li><p>Shorewall-perl insists that ipset names begin with a letter
and be composed of alphanumeric characters and underscores (_). When
used in a Shorewall configuration file, the name must be preceded by
a plus sign (+) as with the shell-based compiler.</p><p>Shorewall is now out of the ipset load/reload business. With
scripts generated by the Perl-based Compiler, the Netfilter rule set
is never cleared. That means that there is no opportunity for
Shorewall to load/reload your ipsets since that cannot be done while
there are any current rules using ipsets.</p><p>So:</p><div class="orderedlist"><ol type="I"><li><p>Your ipsets must be loaded before Shorewall starts. You
are free to try to do that with the following code in
<code class="filename">/etc/shorewall/init (it works for me; your mileage may
vary)</code>:</p><pre class="programlisting">if [ "$COMMAND" = start ]; then
ipset -U :all: :all:
ipset -U :all: :default:
ipset -F
ipset -X
ipset -R < /etc/shorewall/ipsets
fi</pre><p>The file <code class="filename">/etc/shorewall/ipsets</code> will
normally be produced using the <span class="command"><strong>ipset -S</strong></span>
command.</p><p>The above will work most of the time but will fail in a
<span class="command"><strong>shorewall stop</strong></span> - <span class="command"><strong>shorewall
start</strong></span> sequence if you use ipsets in your routestopped
file (see below).</p></li><li><p>Your ipsets may not be reloaded until Shorewall is stopped
or cleared.</p></li><li><p>If you specify ipsets in your routestopped file then
Shorewall must be cleared in order to reload your ipsets.</p></li></ol></div><p>As a consequence, scripts generated by the Perl-based compiler
will ignore <code class="filename">/etc/shorewall/ipsets</code> and will
issue a warning if you set SAVE_IPSETS=Yes in
<code class="filename">shorewall.conf</code>.</p></li><li><p>Because the configuration files (with the exception of
<code class="filename">/etc/shorewall/params</code>) are now processed by the
Shorewall-perl compiler rather than by the shell, only the basic
forms of Shell expansion ($variable and ${variable}) are supported.
The more exotic forms such as ${variable:=default} are not
supported. Both variables defined in /etc/shorewall/params and
environmental variables (exported by the shell) can be used in
configuration files.</p></li><li><p>USE_ACTIONS=No is not supported. That option is intended to
minimize Shorewall's footprint in embedded applications. As a
consequence, Default Macros are not supported.</p></li><li><p>DELAYBLACKLISTLOAD=Yes is not supported. The entire rule set
is atomically loaded with one execution of
<span class="command"><strong>iptables-restore</strong></span>.</p></li><li><p>MAPOLDACTIONS=Yes is not supported. People should have
converted to using macros by now.</p></li><li><p>The pre Shorewall-3.0 format of the zones file is not
supported (IPSECFILE=ipsec); neither is the
<code class="filename">/etc/shorewall/ipsec</code> file.</p></li><li><p>BLACKLISTNEWONLY=No is not permitted with FASTACCEPT=Yes. This
combination doesn't work in previous versions of Shorewall so the
Perl-based compiler simply rejects it.</p></li><li><p>Shorewall-perl has a single rule generator that is used for
all rule-oriented files. So it is important that the syntax is
consistent between files.</p><p>With shorewall-shell, there is a special syntax in the SOURCE
column of /etc/shorewall/masq to designate "all traffic entering the
firewall on this interface except...".</p><p>Example:</p><pre class="programlisting">#INTERFACE SOURCE ADDRESSES
eth0 eth1!192.168.4.9 ...</pre><p>Shorewall-perl
uses syntax that is consistent with the rest of
Shorewall:</p><pre class="programlisting">#INTERFACE SOURCE ADDRESSES
eth0 eth1:!192.168.4.9 ...</pre></li><li><p>The 'allowoutUPnP' built-in action is no longer supported. In
kernel 2.6.14, the Netfilter team have removed support for '-m owner
--owner-cmd' which that action depended on.</p></li><li><p>The PKTTYPE option is ignored by Shorewall-perl.
Shorewall-perl 4.0.0 requires Address type match. Shorewall-perl
versions 4.0.1 and later will use Address type match if it is
available; otherwise, they will behave as if PKTTYPE=No had been
specified.</p></li><li><p>Shorewall-perl detects dead policy file entries that result
when an entry is masked by an earlier more general entry.</p><p>Example:</p><pre class="programlisting">#SOURCE DEST POLICY LOG LEVEL
all all REJECT info
loc net ACCEPT</pre></li><li><p>In the SOURCE column of the rules file, when an interface name
is followed by a list of IP addresses, the behavior of
Shorewall-perl differs from that of Shorewall-shell.</p><p>Example:</p><pre class="programlisting">#ACTION SOURCE DEST PROTO DEST
# PORT(S)
ACCEPT loc:eth0:192.168.1.3,192.168.1.5 $FW tcp 22</pre><p>With
Shorewall-shell, this rule accepts SSH connection to the firewall
from 192.168.1.3 through eth0 or from 192.168.1.5 through any
interface. With Shorewall-perl, the rule accepts SSH connections
through eth0 from 192.168.1.3 and through eth0 from 192.168.1.5.
Shorewall-shell supports this syntax that gives the same result as
Shorewall-perl.</p><pre class="programlisting">#ACTION SOURCE DEST PROTO DEST
# PORT(S)
ACCEPT loc:eth0:192.168.1.3,eth0:192.168.1.5 $fw tcp 22</pre><p>
Shorewall-perl does not support this alternative syntax.</p></li></ol></div></div><div class="section" lang="en" xml:lang="en"><div class="titlepage"><div><div><h3 class="title"><a id="PerlDep"></a>Dependence on Perl</h3></div></div></div><p>Shorewall-perl is dependent on Perl (see the next section) which
has a large disk footprint. This makes Shorewall-perl less desirable in
an embedded environment.</p></div></div><div class="section" lang="en" xml:lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="Prerequisites"></a>Shorewall-perl - Prerequisites</h2></div></div></div><div class="itemizedlist"><ul type="disc"><li><p>Perl (I use Perl 5.8.8 but other 5.8 or later versions should
work fine)</p></li><li><p>Perl Cwd Module</p></li><li><p>Perl File::Basename Module</p></li><li><p>Perl File::Temp Module</p></li><li><p>Perl Getopt::Long Module</p></li><li><p>Perl Carp Module</p></li><li><p>Perl FindBin Module (Shorewall 4.0.3 and later)</p></li><li><p>Perl Scalar::Util Module (Shorewall 4.0.6 and later)</p></li></ul></div></div><div class="section" lang="en" xml:lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="Install"></a>Shorewall-perl - Installation</h2></div></div></div><p>Either</p><pre class="programlisting"><span class="command"><strong>tar -jxf shorewall-perl-4.0.x.tar.bz2</strong></span>
<span class="command"><strong>cd shorewall-perl-4.0.x</strong></span>
<span class="command"><strong>./install.sh</strong></span></pre><p>or</p><pre class="programlisting"><span class="command"><strong>rpm -ivh shorewall-perl-4.0.x.noarch.rpm</strong></span></pre></div><div class="section" lang="en" xml:lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="Using"></a>Using Shorewall-perl</h2></div></div></div><p>If you only install one compiler, then that compiler will be
used.</p><p>If you install both compilers, then the compiler actually used
depends on the SHOREWALL_COMPILER setting in
<code class="filename">shorewall.conf</code>. The value of this option can be
either 'perl' or 'shell'.</p><p>If you add 'SHOREWALL_COMPILER=perl' to
<code class="filename">/etc/shorewall/shorewall.conf</code> then by default, the
new compiler will be used on the system. If you add it to
<code class="filename">shorewall.conf</code> in a separate directory (such as a
Shorewall-lite export directory) then the new compiler will only be used
when you compile from that directory.</p><p>If you only install one compiler, it is suggested that you do not
set SHOREWALL_COMPILER.</p><p>You may also select the compiler to use on the command line using
the 'C option:</p><table class="simplelist" border="0" summary="Simple list"><tr><td>'-C shell' means use the shell compiler</td></tr><tr><td>'-C perl' means use the perl compiler</td></tr></table><p>The -C option overrides the setting in
shorewall.conf.</p><p>Example:</p><pre class="programlisting"><span class="command"><strong>shorewall restart -C perl</strong></span></pre><p>When the Shorewall-perl compiler has been selected, the
<code class="filename">params</code> file is processed twice, the second time using
the <code class="option">-a</code> option which causes all variables set within the
file to be exported automatically by the shell. The Shorewall-perl
compiler uses the current environmental variables to perform variable
expansion within the other Shorewall configuration files.</p></div><div class="section" lang="en" xml:lang="en"><div class="titlepage"><div><div><h2 class="title" style="clear: both"><a id="Modules"></a>The Shorewall Perl Modules</h2></div></div></div><p>Shorewall's Perl modules are installed in
/usr/share/shorewall-perl/Shorewall and the names of the packages are of
the form Shorewall::<em class="firstterm">name</em>. So by using this
directive</p><pre class="programlisting">use lib '/usr/share/shorewall-perl';</pre><p>You can then load the modules via normal Perl use statements.</p><div class="section" lang="en" xml:lang="en"><div class="titlepage"><div><div><h3 class="title"><a id="compiler.pl"></a>/usr/share/shorewall-perl/compiler.pl</h3></div></div></div><p>While the compiler is normally run indirectly using
/sbin/shorewall, it can be run directly as well.</p><pre class="programlisting"><span class="command"><strong>compiler.pl</strong></span> [ <span class="emphasis"><em>option</em></span> ... ] [ <span class="emphasis"><em>filename</em></span> ]</pre><p>If a <span class="emphasis"><em>filename</em></span> is given, then the
configuration will be compiled and the output placed in the named file.
If <span class="emphasis"><em>filename</em></span> is not given, then the configuration
will simply be syntax checked.</p><p>Options are:</p><table class="simplelist" border="0" summary="Simple list"><tr><td><span class="command"><strong>-v</strong></span><<span class="emphasis"><em>verbosity</em></span>></td></tr><tr><td><span class="command"><strong>--verbosity=</strong></span><<span class="emphasis"><em>verbosity</em></span>></td></tr></table><p>The <<span class="emphasis"><em>verbosity</em></span>> is a number
between 0 and 2 and corresponds to the VERBOSITY setting in
<code class="filename">shorewall.conf</code>. This setting controls the verbosity
of the compiler itself.</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>The VERBOSITY setting in the
<code class="filename">shorewall.conf</code> file read by the compiler will
determine the default verbosity for the compiled program.</p></div><table class="simplelist" border="0" summary="Simple list"><tr><td><span class="bold"><strong>-e</strong></span></td></tr><tr><td><span class="bold"><strong>--export</strong></span></td></tr></table><p>If given, the configuration will be compiled for export
to another system.</p><table class="simplelist" border="0" summary="Simple list"><tr><td><span class="bold"><strong>-d</strong></span>
<<span class="emphasis"><em>directory</em></span>></td></tr><tr><td><span class="bold"><strong>--directory=</strong></span><<span class="emphasis"><em>directory</em></span>></td></tr></table><p>If this option is omitted, the configuration in
/etc/shorewall is compiled/checked. Otherwise, the configuration in the
named directory will be compiled/checked.</p><table class="simplelist" border="0" summary="Simple list"><tr><td><span class="bold"><strong>-t</strong></span></td></tr><tr><td><span class="bold"><strong>--timestamp</strong></span></td></tr></table><p>If given, each progress message issued by the compiler
and by the compiled program will be timestamped.</p><table class="simplelist" border="0" summary="Simple list"><tr><td><span class="bold"><strong>--debug</strong></span></td></tr></table><p>If given, when a warning or error message is issued, it
is supplemented with a stack trace. Requires the Carp Perl
module.</p><table class="simplelist" border="0" summary="Simple list"><tr><td><span class="bold"><strong>--refresh=</strong></span><<span class="emphasis"><em>chainlist</em></span>></td></tr></table><p>If given, the compiled script's 'refresh' command will
refresh the chains in the comma-separated
<<span class="emphasis"><em>chainlist</em></span>> rather than
'blacklst'.</p><table class="simplelist" border="0" summary="Simple list"><tr><td><span class="bold"><strong>--log</strong></span>=<logfile></td></tr></table><p>Added in Shorewall 4.2. If given, compiler will log to this file
provider that --log_verbosity is > -1.</p><table class="simplelist" border="0" summary="Simple list"><tr><td><span class="bold"><strong>--log_verbosity</strong></span>=-1|0|1|2</td></tr></table><p>Added in Shorewall 4.1. If given, controls the verbosity of
logging to the log specified by the --log parameter.</p><p>Example (compiles the configuration in the current directory
generating a script named 'firewall' and using VERBOSITY
2).</p><pre class="programlisting"><span class="bold"><strong>/usr/share/shorewall-perl/compiler.pl -v 2 -d . firewall</strong></span></pre><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>The Perl-based compiler does not process
<code class="filename">/etc/shorewall/params</code>. To include definitions
in that file, you would need to do something like the
following:</p><pre class="programlisting"><span class="command"><strong>. /usr/share/shorewall/lib.base # In case /etc/shorewall/params does INCLUDE
set -a # Export all variables set in /etc/shorewall/params
. /etc/shorewall/params
set +a
/usr/share/shorewall-perl/compiler.pl ...</strong></span></pre></div></div><div class="section" lang="en" xml:lang="en"><div class="titlepage"><div><div><h3 class="title"><a id="Compiler"></a>Shorewall::Compiler</h3></div></div></div><div class="section" lang="en" xml:lang="en"><div class="titlepage"><div><div><h4 class="title"><a id="Compiler-4.0"></a>Shorewall 4.0</h4></div></div></div><pre class="programlisting"> use lib '/usr/share/shorewall-perl';
use Shorewall::Compiler;
compiler $filename, $directory, $verbose, $options $chains</pre><p>Arguments
to the compiler are:</p><div class="variablelist"><dl><dt><span class="term">$filename</span></dt><dd><p>Name of the compiled script to be created. If the
arguments evaluates to false, the configuration is syntax
checked.</p></dd><dt><span class="term">$directory</span></dt><dd><p>The directory containing the configuration. If passed as
'', then <code class="filename">/etc/shorewall/</code>
is assumed.</p></dd><dt><span class="term">$verbose</span></dt><dd><p>The verbosity level that the compiler will run with
(0-2).</p><div class="note" style="margin-left: 0.5in; margin-right: 0.5in;"><h3 class="title">Note</h3><p>The VERBOSITY setting in the
<code class="filename">shorewall.conf</code> file read by the
compiler will determine the default verbosity for the
compiled program.</p></div></dd><dt><span class="term">$options</span></dt><dd><p>A bitmap of options. Shorewall::Compiler exports three
constants to help building this argument:</p><table class="simplelist" border="0" summary="Simple list"><tr><td>EXPORT = 0x01</td></tr><tr><td>TIMESTAMP = 0x02</td></tr><tr><td>DEBUG = 0x04</td></tr></table></dd><dt><span class="term">$chains</span></dt><dd><p>A comma-separated list of chains that the generated
script's 'refresh' command will reload. If passed as an empty
string, then 'blacklist' is assumed.</p></dd></dl></div><p>The compiler raises an exception with 'die' if it encounters an
error; $@ contains the 'ERROR' messages describing the problem. The
compiler function can be called repeatedly with different
inputs.</p></div><div class="section" lang="en" xml:lang="en"><div class="titlepage"><div><div><h4 class="title"><a id="id302969"></a>Shorewall 4.2 and Later</h4></div></div></div><p>To avoid a proliferation of parameters to
Shorewall::Compiler::compile(), that function has been changed to use
named parameters. Parameter names are:</p><div class="variablelist"><dl><dt><span class="term">object</span></dt><dd><p>Object file. If omitted or '', the configuration is syntax
checked.</p></dd><dt><span class="term">directory</span></dt><dd><p>Directory. If omitted or '', configuration files are
located using CONFIG_PATH. Otherwise, the directory named by
this parameter is searched first.</p></dd><dt><span class="term">verbosity</span></dt><dd><p>Verbosity; range -1 to 2</p></dd><dt><span class="term">timestamp</span></dt><dd><p>0|1 -- timestamp messages.</p></dd><dt><span class="term">debug</span></dt><dd><p>0|1 -- include stack trace in warning/error
messages.</p></dd><dt><span class="term">export</span></dt><dd><p>0|1 -- compile for export.</p></dd><dt><span class="term">chains</span></dt><dd><p>List of chains to be reloaded by 'refresh'</p></dd><dt><span class="term">log</span></dt><dd><p>File to log compiler messages to.</p></dd><dt><span class="term">log_verbosity</span></dt><dd><p>Log Verbosity; range -1 to 2.</p></dd></dl></div><p>Those parameters that are supplied must have defined values.
Defaults are: </p><table class="simplelist" border="0" summary="Simple list"><tr><td>object '' ('check' command)</td></tr><tr><td>directory ''</td></tr><tr><td>verbosity 1</td></tr><tr><td>timestamp 0</td></tr><tr><td>debug 0</td></tr><tr><td>export 0</td></tr><tr><td>chains ''</td></tr><tr><td>log ''</td></tr><tr><td>log_verbosity -1</td></tr></table><p>Example: </p><pre class="programlisting">use lib '/usr/share/shorewall-perl/';
use Shorewall::Compiler;
compiler( object => '/root/firewall', log => '/root/compile.log', log_verbosity => 2 ); </pre></div></div><div class="section" lang="en" xml:lang="en"><div class="titlepage"><div><div><h3 class="title"><a id="Chains"></a>Shorewall::Chains</h3></div></div></div><pre class="programlisting">use lib '/usr/share/shorewall-perl';
use Shorewall::Chains;
my $chainref1 = chain_new $table, $name1;
add_rule $chainref1, $rule;
insert_rule $chainref1, $ordinal, $rule;
my $chainref2 = new_manual_chain $name3;
my $chainref3 = ensure_manual_chain $name;
log_rule_limit $level, $chainref3, $name, $disposition, $limit, $tag, $command, $predicates;
my $chainref4 = $chain_table{$table}{$name};
my $chainref5 = $nat_table{$name};
my $chainref6 = $mangle_table{$name};
my $chainref7 = $filter_table{$name};</pre><p>Shorewall::Chains is
Shorewall-perl's interface to iptables/netfilter. It creates a
<em class="firstterm">chain table</em> (%chain_table) which is populated as
the various tables are processed. The table (actually a hash) is
two-dimensional with the first dimension being the Netfilter table name
(raw, mangle, nat and filter) and the second dimension being the chain
name. Each table is a hash reference -- the hash defines the attributes
of the chain. See the large comment at the beginning of the module
(<code class="filename">/usr/share/shorewall-perl/Shorewall/Chains.pm</code>).</p><p>The module export the chain table along with three hash references
into the table:<code class="literal"></code></p><div class="variablelist"><dl><dt><span class="term">$nat_table</span></dt><dd><p>Reference to the 'nat' portion of the table
($chain_table{nat}). This is a hash whose key is the chain
name.</p></dd><dt><span class="term">$mangle_table</span></dt><dd><p>Reference to the 'mangle' portion of the table
($chain_table{mangle}). This is a hash whose key is the chain
name.</p></dd><dt><span class="term">$filter</span></dt><dd><p>Reference to the 'filter' portion of the table
($chain_table{filter}). This is a hash whose key is the chain
name.</p></dd></dl></div><p>You can create a new chain in any of the tables using <span class="bold"><strong>new_chain()</strong></span>. Arguments to the function
are:</p><div class="variablelist"><dl><dt><span class="term">$table</span></dt><dd><p>'nat', 'mangle', or 'filter'.</p></dd><dt><span class="term">$name</span></dt><dd><p>Name of the chain to create.</p></dd></dl></div><p>The function creates a hash at $chain_table{$table}{$name} and
populates the hash with default values. A reference to the hash is
returned.</p><p>Each chain table entry includes a list of rules to be added to the
chain. These rules are written to the iptables-restore input file when
the resulting script is executed. To append a rule to that list, call
<span class="bold"><strong>add_rule()</strong></span>. Arguments are:</p><div class="variablelist"><dl><dt><span class="term">$chainref</span></dt><dd><p>A reference to the chain table entry.</p></dd><dt><span class="term">$rule</span></dt><dd><p>The rule to add. Do not include the leading '-A ' in this
argument -- it will be supplied by the function.</p></dd></dl></div><p>To insert a rule into that list, call <span class="bold"><strong>insert_rule()</strong></span>. Arguments are:</p><div class="variablelist"><dl><dt><span class="term">$chainref</span></dt><dd><p>A reference to the chain table entry.</p></dd><dt><span class="term">$ordinal</span></dt><dd><p>The position of the inserted rule in the list. A value of 1
inserts the rule at the head of the list, a value of 2 places the
rule second in the list, and so on.</p></dd><dt><span class="term">$rule</span></dt><dd><p>The rule to add. Do not include the leading '-I' in this
argument -- it will be supplied by the function.</p></dd></dl></div><p>To create a <a class="ulink" href="ManualChains.html" target="_self">manual chain</a>,
use the new_manual_chain() function. The function accepts a single
argument which is the name of the chain. The function returns a
reference to the resulting chain table entry.</p><p>A companion function, <span class="bold"><strong>ensure_manual_chain()</strong></span>, can be called when a
manual chain of the desired name may have already been created. If a
manual chain table entry with the passed name already exists, a
reference to the chain table entry is returned. Otherwise, the function
calls <span class="bold"><strong>new_manual_chain()</strong></span> and returns
the result.</p><p>To create a logging rule, call <span class="bold"><strong>log_rule_limit()</strong></span>. Arguments are:</p><div class="variablelist"><dl><dt><span class="term">$level</span></dt><dd><p>The log level. May be specified as a name or as a
number.</p></dd><dt><span class="term">$chainref</span></dt><dd><p>Chain table reference for the chain to which the rule is to
be added.</p></dd><dt><span class="term">$name</span></dt><dd><p>The chain name to be reported in the log message (see
LOGFORMAT in <a class="ulink" href="manpages/shorewall.conf.html" target="_self">shorewall.conf</a>(5)).</p></dd><dt><span class="term">$disposition</span></dt><dd><p>The disposition to be reported in the log message (see
LOGFORMAT in <a class="ulink" href="manpages/shorewall.conf.html" target="_self">shorewall.conf</a>(5)).</p></dd><dt><span class="term">$limit</span></dt><dd><p>Rate limiting match. If an empty string is passed, the
LOGRATE/LOGBURST (<a class="ulink" href="manpages/shorewall.conf.html" target="_self">shorewall.conf</a>(5)) is
used.</p></dd><dt><span class="term">$tag</span></dt><dd><p>Log tag.</p></dd><dt><span class="term">$command</span></dt><dd><p>If 'add', append the log rule to the chain. If 'insert',
then insert the rule at the beginning of the chain.</p></dd><dt><span class="term">$predicates</span></dt><dd><p>Any additional matches that are to be applied to the
rule.</p></dd></dl></div></div><div class="section" lang="en" xml:lang="en"><div class="titlepage"><div><div><h3 class="title"><a id="Config"></a>Shorewall::Config</h3></div></div></div><pre class="programlisting">use lib '/usr/share/shorewall-perl';
use Shorewall::Config;
warning message "This entry is bogus";
fatal_error "You have made an error";
progress_message "This will only be seen if VERBOSITY >= 2";
progress_message2 "This will only be seen if VERBOSITY >= 1";
progress_message3 "This will be seen unless VERBOSITY < 0";
</pre><p>The <span class="bold"><strong>shorewall()</strong></span> function may
be optionally included.</p><pre class="programlisting">use lib '/usr/share/shorewall-perl';
use Shorewall::Config qw/shorewall/;
shorewall $config_file_entry;</pre><p>The Shorewall::Config module
provides basic services to Shorewall-perl. By default, it exports the
functions that produce progress messages and warning/error
messages.</p><p>To issue a warning message, call <span class="bold"><strong>warning_message()</strong></span>. The single argument describes
the warning.</p><p>To raise a fatal error, call <span class="bold"><strong>fatal_error()</strong></span>. Again, the single argument
described the error.</p><p>In both cases, the function will augment the warning/error with
the current configuration file and line number, if any. <span class="bold"><strong>fatal_error()</strong></span> raised an exception via either
<span class="bold"><strong>confess()</strong></span> or <span class="bold"><strong>die()</strong></span>, depending on whether the debugging stack
trace is enabled or not..</p><p>The three 'progress message' functions conditionally produce
output depending on the current verbosity setting.</p><p>The <span class="bold"><strong>shorewall()</strong></span> function is used
by <a class="ulink" href="configuration_file_basics.htm#Embedded" target="_self">embedded Perl
scripts</a> to generate entries to be included in the current
configuration file.</p></div></div></div></body></html>
