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Break the extension script doc into sections

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docs/shorewall_extension_scripts.xml
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@ -5,7 +5,7 @@
<!--$Id$--> <!--$Id$-->
<articleinfo> <articleinfo>
<title>Extension Scripts and Default Actions</title> <title>Extension Scripts</title>
<authorgroup> <authorgroup>
<author> <author>
@ -34,12 +34,8 @@
</legalnotice> </legalnotice>
</articleinfo> </articleinfo>
<caution> <section id="Scripts">
<para><emphasis role="bold">This article applies to Shorewall 3.0 and <title>Extension Scripts</title>
later. If you are running a version of Shorewall earlier than Shorewall
3.0.0 then please see the documentation for that
release.</emphasis></para>
</caution>
<para>Extension scripts are user-provided scripts that are invoked at <para>Extension scripts are user-provided scripts that are invoked at
various points during firewall start, restart, stop and clear. The scripts various points during firewall start, restart, stop and clear. The scripts
@ -49,9 +45,9 @@
<caution> <caution>
<orderedlist> <orderedlist>
<listitem> <listitem>
<para>Be sure that you actually need to use an extension script to do <para>Be sure that you actually need to use an extension script to
what you want. Shorewall has a wide range of features that cover most do what you want. Shorewall has a wide range of features that cover
requirements.</para> most requirements.</para>
</listitem> </listitem>
<listitem> <listitem>
@ -72,8 +68,9 @@
</listitem> </listitem>
<listitem> <listitem>
<para>initdone -- invoked after Shorewall has flushed all existing rules <para>initdone -- invoked after Shorewall has flushed all existing
but before any rules have been added to the builtin chains.</para> rules but before any rules have been added to the builtin
chains.</para>
</listitem> </listitem>
<listitem> <listitem>
@ -105,45 +102,46 @@
</listitem> </listitem>
<listitem> <listitem>
<para>refreshed -- invoked after the firewall has been refreshed.</para> <para>refreshed -- invoked after the firewall has been
refreshed.</para>
</listitem> </listitem>
<listitem> <listitem>
<para>continue -- invoked to allow you to insert special rules to allow <para>continue -- invoked to allow you to insert special rules to
traffic while Shorewall is [re]starting. Any rules added in this script allow traffic while Shorewall is [re]starting. Any rules added in this
should be deleted in your <emphasis>start</emphasis> script. This script script should be deleted in your <emphasis>start</emphasis> script.
is invoked earlier in the [re]start process than is the This script is invoked earlier in the [re]start process than is the
<emphasis>initdone</emphasis> script described above (Not used by <emphasis>initdone</emphasis> script described above (Not used by
Shorewall Perl).</para> Shorewall Perl).</para>
</listitem> </listitem>
<listitem> <listitem>
<para>maclog -- (Added in Shorewall version 3.2.5) invoked while mac <para>maclog -- (Added in Shorewall version 3.2.5) invoked while mac
filtering rules are being created. It is invoked once for each interface filtering rules are being created. It is invoked once for each
having 'maclist' specified and it is invoked just before the logging interface having 'maclist' specified and it is invoked just before the
rule is added to the current chain (the name of that chain will be in logging rule is added to the current chain (the name of that chain
$CHAIN).</para> will be in $CHAIN).</para>
</listitem> </listitem>
</itemizedlist> </itemizedlist>
<para><emphasis role="bold">If your version of Shorewall doesn't have the <para><emphasis role="bold">If your version of Shorewall doesn't have the
file that you want to use from the above list, you can simply create the file that you want to use from the above list, you can simply create the
file yourself.</emphasis> You can also supply a script with the same name as file yourself.</emphasis> You can also supply a script with the same name
any of the filter chains in the firewall and the script will be invoked as any of the filter chains in the firewall and the script will be invoked
after the /etc/shorewall/rules file has been processed but before the after the /etc/shorewall/rules file has been processed but before the
/etc/shorewall/policy file has been processed.</para> /etc/shorewall/policy file has been processed.</para>
<para>There are a couple of special considerations for commands in extension <para>There are a couple of special considerations for commands in
scripts:</para> extension scripts:</para>
<itemizedlist> <itemizedlist>
<listitem> <listitem>
<para>When you want to run <command>iptables</command>, use the command <para>When you want to run <command>iptables</command>, use the
<command>run_iptables</command> instead. <command>run_iptables</command> command <command>run_iptables</command> instead.
will run the iptables utility passing the arguments to <command>run_iptables</command> will run the iptables utility passing
<command>run_iptables</command> and if the command fails, the firewall the arguments to <command>run_iptables</command> and if the command
will be stopped (or restored from the last <command>save</command> fails, the firewall will be stopped (or restored from the last
command, if any).</para> <command>save</command> command, if any).</para>
</listitem> </listitem>
<listitem> <listitem>
@ -162,8 +160,8 @@
<listitem> <listitem>
<para>Chain name to display in the message (this can be different <para>Chain name to display in the message (this can be different
from the preceding argument — see the <ulink from the preceding argument — see the <ulink
url="PortKnocking.html">Port Knocking article</ulink> for an example url="PortKnocking.html">Port Knocking article</ulink> for an
of how to use this).</para> example of how to use this).</para>
</listitem> </listitem>
<listitem> <listitem>
@ -186,30 +184,35 @@
</listitem> </listitem>
<listitem> <listitem>
<para>The remaining arguments are passed "as is" to iptables</para> <para>The remaining arguments are passed "as is" to
iptables</para>
</listitem> </listitem>
</itemizedlist> </itemizedlist>
</listitem> </listitem>
<listitem> <listitem>
<para>Many of the extension scripts get executed for both the shorewall <para>Many of the extension scripts get executed for both the
start and shorewall restart commands. You can determine which command is shorewall start and shorewall restart commands. You can determine
being executed using the contents of $COMMAND.</para> which command is being executed using the contents of $COMMAND.</para>
<programlisting>if [ $COMMAND = start ]; then <programlisting>if [ $COMMAND = start ]; then
...</programlisting> ...</programlisting>
</listitem> </listitem>
</itemizedlist>
<listitem> <para></para>
<para><emphasis role="bold">Shorewall versions 3.0.x and earlier
only.</emphasis> If you run commands other than <section id="v3.0">
<command>iptables</command> that must be re-run in order to restore the <title>Shorewall versions 3.0.x and earlier</title>
firewall to its current state then you must save the commands to the
<firstterm>restore file</firstterm>. The restore file is a temporary <para>If you run commands other than <command>iptables</command> that
file in <filename class="directory">/var/lib/shorewall</filename> that must be re-run in order to restore the firewall to its current state
will be renamed <filename>/var/lib/shorewall/restore-base</filename> at then you must save the commands to the <firstterm>restore
the successful completion of the Shorewall command. The file</firstterm>. The restore file is a temporary file in <filename
<command>shorewall save</command> command combines class="directory">/var/lib/shorewall</filename> that will be renamed
<filename>/var/lib/shorewall/restore-base</filename> at the successful
completion of the Shorewall command. The <command>shorewall
save</command> command combines
<filename>/var/lib/shorewall/restore-base</filename> with the output of <filename>/var/lib/shorewall/restore-base</filename> with the output of
<command>iptables-save</command> to produce the <command>iptables-save</command> to produce the
<filename>/var/lib/shorewall/restore</filename> script.</para> <filename>/var/lib/shorewall/restore</filename> script.</para>
@ -247,21 +250,21 @@
file</para> file</para>
</listitem> </listitem>
</orderedlist> </orderedlist>
</listitem> </section>
<listitem> <section id="v3.2">
<para><emphasis role="bold">Shorewall version 3.2.0 - 3.2.8 <title>Shorewall version 3.2.0 - 3.2.8</title>
only.</emphasis> When compiling your firewall configuration, Shorewall
copies most extension scripts directly into the "compiled" program where <para>When compiling your firewall configuration, Shorewall copies most
they are executed in-line during processing of the start, restart and extension scripts directly into the "compiled" program where they are
restore commands. When copying a script, Shorewall indents the script to executed in-line during processing of the start, restart and restore
match the surrounding code; if you have 'awk' installed on the system commands. When copying a script, Shorewall indents the script to match
where the configuration is being compiled, Shorewall can correctly the surrounding code; if you have 'awk' installed on the system where
handle line continuation in your script ("\" as the last character on a the configuration is being compiled, Shorewall can correctly handle line
line). If you do not have awk, you may not use line continuation in your continuation in your script ("\" as the last character on a line). If
scripts. Also beware that quoted strings continued from one line to you do not have awk, you may not use line continuation in your scripts.
another will have extra whitespace inserted as a result of Also beware that quoted strings continued from one line to another will
indentation.</para> have extra whitespace inserted as a result of indentation.</para>
<note> <note>
<para>The <filename>/etc/shorewall/params</filename> script is <para>The <filename>/etc/shorewall/params</filename> script is
@ -285,21 +288,22 @@
processed by the compiler rather than copied into the compiled processed by the compiler rather than copied into the compiled
script.</para> script.</para>
</note> </note>
</listitem> </section>
<listitem> <section id="v3.2.9">
<para><emphasis role="bold">Shorewall version 3.2.9 (3.4.0 RC2) and <title>Shorewall version 3.2.9 (3.4.0 RC2) and later
later (Shorewall-shell).</emphasis> When compiling your firewall (Shorewall-shell)</title>
configuration, Shorewall copies most extension scripts directly into the
"compiled" program where they are executed in-line during processing of <para>When compiling your firewall configuration, Shorewall copies most
the start, restart and restore commands. When copying a script, extension scripts directly into the "compiled" program where they are
Shorewall indents the script to match the surrounding code; if you have executed in-line during processing of the start, restart and restore
'awk' installed on the system where the configuration is being compiled, commands. When copying a script, Shorewall indents the script to match
Shorewall can correctly handle line continuation in your script ("\" as the surrounding code; if you have 'awk' installed on the system where
the last character on a line). If you do not have awk, you may not use the configuration is being compiled, Shorewall can correctly handle line
line continuation in your scripts. Also beware that quoted strings continuation in your script ("\" as the last character on a line). If
continued from one line to another will have extra whitespace inserted you do not have awk, you may not use line continuation in your scripts.
as a result of indentation.</para> Also beware that quoted strings continued from one line to another will
have extra whitespace inserted as a result of indentation.</para>
<note> <note>
<para>The <filename>/etc/shorewall/params</filename> script is <para>The <filename>/etc/shorewall/params</filename> script is
@ -336,13 +340,15 @@
processed by the compiler rather than copied into the compiled processed by the compiler rather than copied into the compiled
script.</para> script.</para>
</note> </note>
</listitem> </section>
<listitem> <section id="Perl">
<para><emphasis role="bold">Shorewall-perl</emphasis>. Because the <title>Shorewall-perl (Version 4.0.0 and later)</title>
compiler is written in Perl, some of your extension scripts from earlier
versions will no longer work because Shorewall-perl runs those extension <para>Because the compiler is written in Perl, some of your extension
scripts at compile-time rather than at run-time.</para> scripts from earlier versions will no longer work because Shorewall-perl
runs those extension scripts at compile-time rather than at
run-time.</para>
<para>The following table summarizes when the various extension scripts <para>The following table summarizes when the various extension scripts
are run:<informaltable frame="all"> are run:<informaltable frame="all">
@ -443,7 +449,9 @@
<member>$chainref-&gt;{name} contains the name of the chain</member> <member>$chainref-&gt;{name} contains the name of the chain</member>
<member>$chainref-&gt;{table} holds the table name</member> <member>$chainref-&gt;{table} holds the table name</member>
</simplelist>To add a rule to the chain:<programlisting>add_rule( $chainref, &lt;the rule&gt; );</programlisting>Where<simplelist> </simplelist></para>
<para>To add a rule to the chain:<programlisting>add_rule( $chainref, &lt;the rule&gt; );</programlisting>Where<simplelist>
<member>&lt;the rule&gt; is a scalar argument holding the rule text. <member>&lt;the rule&gt; is a scalar argument holding the rule text.
Do not include "-A &lt;chain name&gt;"</member> Do not include "-A &lt;chain name&gt;"</member>
</simplelist>Example:<programlisting>add_rule( $chainref, '-j ACCEPT' );</programlisting>To </simplelist>Example:<programlisting>add_rule( $chainref, '-j ACCEPT' );</programlisting>To
@ -490,6 +498,6 @@
add special temporary rules during [re]start. Shorewall-perl doesn't add special temporary rules during [re]start. Shorewall-perl doesn't
need such rules since the ruleset is instantianted atomically by need such rules since the ruleset is instantianted atomically by
table.</para> table.</para>
</listitem> </section>
</itemizedlist> </section>
</article> </article>