mirror of
https://gitlab.com/shorewall/code.git
synced 2024-11-08 16:54:10 +01:00
7a6ac0a561
git-svn-id: https://shorewall.svn.sourceforge.net/svnroot/shorewall/trunk@6972 fbd18981-670d-0410-9b5c-8dc0c1a9a2bb
599 lines
22 KiB
XML
599 lines
22 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
|
|
<!DOCTYPE article PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
|
|
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
|
|
<article>
|
|
<!--$Id: template.xml 4194 2006-07-07 01:04:16Z judas_iscariote $-->
|
|
|
|
<articleinfo>
|
|
<title>Shorewall-perl</title>
|
|
|
|
<authorgroup>
|
|
<author>
|
|
<firstname>Tom</firstname>
|
|
|
|
<surname>Eastep</surname>
|
|
</author>
|
|
</authorgroup>
|
|
|
|
<pubdate><?dbtimestamp format="Y/m/d"?></pubdate>
|
|
|
|
<copyright>
|
|
<year>2007</year>
|
|
|
|
<holder>Thomas M. Eastep</holder>
|
|
</copyright>
|
|
|
|
<legalnotice>
|
|
<para>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
|
|
<quote><ulink url="GnuCopyright.htm">GNU Free Documentation
|
|
License</ulink></quote>.</para>
|
|
</legalnotice>
|
|
</articleinfo>
|
|
|
|
<section id="What">
|
|
<title>Shorewall-perl - What is it?</title>
|
|
|
|
<para>Shorewall-perl is a companion product to Shorewall.</para>
|
|
|
|
<para>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:</para>
|
|
|
|
<itemizedlist>
|
|
<listitem>
|
|
<para>The Shorewall-perl compiler is much faster.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>The script generated by the compiler uses
|
|
<command>iptables-restore</command> to instantiate the Netfilter
|
|
configuration. So it runs much faster than the script generated by the
|
|
Shorewall-shell compiler.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>The Shorewall-perl compiler does more thorough checking of the
|
|
configuration than the Shorewall-shell compiler does.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>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.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>Going forward, the Shorewall-perl compiler will get all
|
|
enhancements; the Shorewall-shell compiler will only get those
|
|
enhancements that are easy to retrofit.</para>
|
|
</listitem>
|
|
</itemizedlist>
|
|
</section>
|
|
|
|
<section id="DownSide">
|
|
<title>Shorewall-perl - The down side</title>
|
|
|
|
<para>While there are advantages to using Shorewall-perl, there are also
|
|
disadvantages:</para>
|
|
|
|
<itemizedlist>
|
|
<listitem>
|
|
<para>There are a number of incompatibilities between the
|
|
Shorewall-perl compiler and the earlier one.</para>
|
|
|
|
<orderedlist>
|
|
<listitem>
|
|
<para>The Perl-based compiler requires the following capabilities
|
|
in your kernel and iptables.</para>
|
|
|
|
<itemizedlist>
|
|
<listitem>
|
|
<para>addrtype match (Restriction relaxed in Shorewall-perl
|
|
4.0.1)</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>multiport match (will not be relaxed)</para>
|
|
</listitem>
|
|
</itemizedlist>
|
|
|
|
<para>These capabilities are in current distributions.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>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.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>BRIDGING=Yes is not supported. The kernel code necessary to
|
|
support this option was removed in Linux kernel 2.6.20. <ulink
|
|
url="bridge-Shorewall-perl.html">Alternative bridge
|
|
support</ulink> is provided by Shorewall-perl.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>The BROADCAST column in the interfaces file is essentially
|
|
unused; if you enter anything in this column but '-' or 'detect',
|
|
you will receive a warning. This will be relaxed if and when the
|
|
addrtype match requirement is relaxed.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>The 'refresh' command is now similar to restart with the
|
|
exceptios that:</para>
|
|
|
|
<itemizedlist>
|
|
<listitem>
|
|
<para>The command fails if Shorewall is not running.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>A directory name cannot be specified in the
|
|
command.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>The refresh command does not alter the Netfilter
|
|
configuration except for the static blacklist.</para>
|
|
</listitem>
|
|
</itemizedlist>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>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 ruleset is built by the compiler. As a result,
|
|
Shorewall-perl runs many 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.</para>
|
|
|
|
<para>The following table summarizes when the various extension
|
|
scripts are run:<informaltable frame="all">
|
|
<tgroup cols="3">
|
|
<tbody>
|
|
<row>
|
|
<entry><emphasis
|
|
role="bold">Compile-time</emphasis></entry>
|
|
|
|
<entry><emphasis role="bold">Run-time</emphasis></entry>
|
|
|
|
<entry><emphasis
|
|
role="bold">Eliminated</emphasis></entry>
|
|
</row>
|
|
|
|
<row>
|
|
<entry>initdone</entry>
|
|
|
|
<entry>clear</entry>
|
|
|
|
<entry>continue</entry>
|
|
</row>
|
|
|
|
<row>
|
|
<entry>maclog</entry>
|
|
|
|
<entry>initdone</entry>
|
|
|
|
<entry></entry>
|
|
</row>
|
|
|
|
<row>
|
|
<entry>Per-chain (including those associated with
|
|
actions)</entry>
|
|
|
|
<entry>start</entry>
|
|
|
|
<entry></entry>
|
|
</row>
|
|
|
|
<row>
|
|
<entry></entry>
|
|
|
|
<entry>started</entry>
|
|
|
|
<entry></entry>
|
|
</row>
|
|
|
|
<row>
|
|
<entry></entry>
|
|
|
|
<entry>stop</entry>
|
|
|
|
<entry></entry>
|
|
</row>
|
|
|
|
<row>
|
|
<entry></entry>
|
|
|
|
<entry>stopped</entry>
|
|
|
|
<entry></entry>
|
|
</row>
|
|
|
|
<row>
|
|
<entry></entry>
|
|
|
|
<entry>tcclear</entry>
|
|
|
|
<entry></entry>
|
|
</row>
|
|
</tbody>
|
|
</tgroup>
|
|
</informaltable></para>
|
|
|
|
<para>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.</para>
|
|
|
|
<para>When a script is invoked, the <emphasis
|
|
role="bold">$chainref</emphasis> scalar variable will hold a
|
|
reference to a chain table entry.</para>
|
|
|
|
<simplelist>
|
|
<member><emphasis role="bold">$chainref->{name}</emphasis>
|
|
contains the name of the chain</member>
|
|
|
|
<member><emphasis role="bold">$chainref->{table}</emphasis>
|
|
holds the table name</member>
|
|
</simplelist>
|
|
|
|
<para>To add a rule to the chain:</para>
|
|
|
|
<simplelist>
|
|
<member>add_rule $chainref, <<replaceable>the
|
|
rule</replaceable>></member>
|
|
</simplelist>
|
|
|
|
<para>Where</para>
|
|
|
|
<simplelist>
|
|
<member><<replaceable>the rule</replaceable>> is a scalar
|
|
argument holding the rule text. Do not include "-A
|
|
<<replaceable>chain name</replaceable>>"</member>
|
|
</simplelist>
|
|
|
|
<para>Example:</para>
|
|
|
|
<simplelist>
|
|
<member>add_rule $chainref, '-j ACCEPT';</member>
|
|
</simplelist>
|
|
|
|
<para>To insert a rule into the chain:</para>
|
|
|
|
<simplelist>
|
|
<member>insert_rule $chainref,
|
|
<<replaceable>rulenum</replaceable>>, <<replaceable>the
|
|
rule</replaceable>></member>
|
|
</simplelist>
|
|
|
|
<para>The log_rule_limit function works like it does in the shell
|
|
compiler with two exceptions:</para>
|
|
|
|
<itemizedlist>
|
|
<listitem>
|
|
<para>You pass the chain reference rather than the name of the
|
|
chain.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>The commands are 'add' and 'insert' rather than '-A' and
|
|
'-I'.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>There is only a single "pass as-is to iptables" argument
|
|
(so you must quote that part</para>
|
|
</listitem>
|
|
</itemizedlist>
|
|
|
|
<para>Example:</para>
|
|
|
|
<programlisting> log_rule_limit
|
|
'info' ,
|
|
$chainref ,
|
|
$chainref->{name},
|
|
'DROP' ,
|
|
'', #Limit
|
|
'' , #Log tag
|
|
'add'
|
|
'-p tcp '; </programlisting>
|
|
|
|
<para>Here is an example of an actual initdone script used with
|
|
Shorewall 3.4:<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
|
|
</programlisting></para>
|
|
|
|
<para>Here is the corresponding script used with
|
|
Shorewall-perl:<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;</programlisting></para>
|
|
|
|
<para>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 $nat_table
|
|
references can be used to add or insert rules in arbitrary
|
|
chains.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>The <filename>/etc/shorewall/tos</filename> file now has
|
|
zone-independent SOURCE and DEST columns as do all other files
|
|
except the rules and policy files.</para>
|
|
|
|
<para>The SOURCE column may be one of the following:</para>
|
|
|
|
<simplelist>
|
|
<member>[<command>all</command>:]<<replaceable>address</replaceable>>[,...]</member>
|
|
|
|
<member>[<command>all</command>:]<<replaceable>interface</replaceable>>[:<<replaceable>address</replaceable>>[,...]]</member>
|
|
|
|
<member><command>$FW</command>[:<<replaceable>address</replaceable>>[,...]]</member>
|
|
</simplelist>
|
|
|
|
<para>The DEST column may be one of the following:</para>
|
|
|
|
<simplelist>
|
|
<member>[<command>all</command>:]<<replaceable>address</replaceable>>[,...]</member>
|
|
|
|
<member>[<command>all</command>:]<<replaceable>interface</replaceable>>[:<<replaceable>address</replaceable>>[,...]]</member>
|
|
</simplelist>
|
|
|
|
<para>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.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>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.</para>
|
|
|
|
<para>Shorewall is now out of the ipset load/reload business. With
|
|
scripts generated by the Perl-based Compiler, the Netfilter
|
|
ruleset 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.</para>
|
|
|
|
<para>So:</para>
|
|
|
|
<orderedlist numeration="upperroman">
|
|
<listitem>
|
|
<para>Your ipsets must be loaded before Shorewall starts. You
|
|
are free to try to do that with the following code in
|
|
<filename>/etc/shorewall/start</filename>:</para>
|
|
|
|
<programlisting>if [ "$COMMAND" = start ]; then
|
|
ipset -U :all: :all:
|
|
ipset -F
|
|
ipset -X
|
|
ipset -R < /etc/shorewall/ipsets
|
|
fi</programlisting>
|
|
|
|
<para>The file <filename>/etc/shorewall/ipsets</filename> will
|
|
normally be produced using the <command>ipset -S</command>
|
|
command.</para>
|
|
|
|
<para>The above will work most of the time but will fail in a
|
|
<command>shorewall stop</command> - <command>shorewall
|
|
start</command> sequence if you use ipsets in your
|
|
routestopped file (see below).</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>Your ipsets may not be reloaded until Shorewall is
|
|
stopped or cleared.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>If you specify ipsets in your routestopped file then
|
|
Shorewall must be cleared in order to reload your
|
|
ipsets.</para>
|
|
</listitem>
|
|
</orderedlist>
|
|
|
|
<para>As a consequence, scripts generated by the Perl-based
|
|
compiler will ignore <filename>/etc/shorewall/ipsets</filename>
|
|
and will issue a warning if you set SAVE_IPSETS=Yes in
|
|
<filename>shorewall.conf</filename>.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>Because the configuration files (with the exception of
|
|
<filename>/etc/shorewall/params</filename>) are now processed by
|
|
the Shorewall-perl compiler rather than by the shell, only the
|
|
basic forms of Shell expansion ($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.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>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.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>DELAYBLACKLISTLOAD=Yes is not supported. The entire ruleset
|
|
is atomically loaded with one execution of
|
|
<command>iptables-restore</command>.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>MAPOLDACTIONS=Yes is not supported. People should have
|
|
converted to using macros by now.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>The pre Shorewall-3.0 format of the zones file is not
|
|
supported; neither is the
|
|
<filename>/etc/shorewall/ipsec</filename> file.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>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.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>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.</para>
|
|
|
|
<para>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...".</para>
|
|
|
|
<para>Example:<programlisting>#INTERFACE SOURCE ADDRESSES
|
|
eth0 eth1!192.168.4.9 ...</programlisting>Shorewall-perl
|
|
uses syntax that is consistent with the rest of
|
|
Shorewall:<programlisting>#INTERFACE SOURCE ADDRESSES
|
|
eth0 eth1:!192.168.4.9 ...</programlisting></para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>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.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>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.</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para> Shorewall-perl detects dead policy file entries that result
|
|
when an entry is masked by an earlier more general entry.</para>
|
|
|
|
<para>Example:</para>
|
|
|
|
<programlisting>#SOURCE DEST POLICY LOG LEVEL
|
|
all all REJECT info
|
|
loc net ACCEPT</programlisting>
|
|
</listitem>
|
|
</orderedlist>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>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.</para>
|
|
</listitem>
|
|
</itemizedlist>
|
|
</section>
|
|
|
|
<section id="Prerequisites">
|
|
<title>Shorewall-perl - Prerequisites</title>
|
|
|
|
<itemizedlist>
|
|
<listitem>
|
|
<para>Perl (I use Perl 5.8.8 but other versions should work
|
|
fine)</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>Perl Cwd Module</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>Perl File::Basename Module</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>Perl File::Temp Module</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>Perl Getopts::Long Module</para>
|
|
</listitem>
|
|
|
|
<listitem>
|
|
<para>Perl Carp Module</para>
|
|
</listitem>
|
|
</itemizedlist>
|
|
</section>
|
|
|
|
<section id="Install">
|
|
<title>Shorewall-perl - Installation</title>
|
|
|
|
<para>Either</para>
|
|
|
|
<programlisting><command>tar -jxf shorewall-perl-4.0.x.tar.bz2</command>
|
|
<command>cd shorewall-perl-4.0.x</command>
|
|
<command>./install.sh</command></programlisting>
|
|
|
|
<para>or</para>
|
|
|
|
<programlisting><command>rpm -ivh shorewall-perl-4.0.x.noarch.rpm</command></programlisting>
|
|
</section>
|
|
|
|
<section id="Using">
|
|
<title>Using Shorewall-perl</title>
|
|
|
|
<para>If you only install one compiler, then that compiler will be
|
|
used.</para>
|
|
|
|
<para>If you install both compilers, then the compiler actually used
|
|
depends on the SHOREWALL_COMPILER setting in
|
|
<filename>shorewall.conf</filename>. The value of this option can be
|
|
either 'perl' or 'shell'.</para>
|
|
|
|
<para>If you add 'SHOREWALL_COMPILER=perl' to
|
|
<filename>/etc/shorewall/shorewall.conf</filename> then by default, the
|
|
new compiler will be used on the system. If you add it to
|
|
<filename>shorewall.conf</filename> 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.</para>
|
|
|
|
<para>If you only install one compiler, it is suggested that you do not
|
|
set SHOREWALL_COMPILER.</para>
|
|
|
|
<para>You may also select the compiler to use on the command line using
|
|
the 'C option:<simplelist>
|
|
<member>'-C shell' means use the shell compiler</member>
|
|
|
|
<member>'-C perl' means use the perl compiler</member>
|
|
</simplelist>The -C option overrides the setting in
|
|
shorewall.conf.</para>
|
|
|
|
<para>Example:<programlisting><command>shorewall restart -C perl</command></programlisting></para>
|
|
|
|
<para>When the Shorewall-perl compiler has been selected, the
|
|
<filename>params</filename> file is processed twice, the second time using
|
|
the <option>-a</option> 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.</para>
|
|
</section>
|
|
</article> |