Shorewall-perl

The Perl-based compiler requires the following capabilities in your kernel and iptables.

These capabilities are in current distributions.

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.

BRIDGING=Yes is not supported. The kernel code necessary to support this option was removed in Linux kernel 2.6.20.

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.

Because the compiler is now written in Perl, your compile-time extension scripts from earlier versions will no longer work. For now, if you want to use extension scripts, you will need to read the Perl code to see how the compiler operates internally. I will produce documentation before the first official release. Compile-time extension scripts are executed using the Perl 'do FILE' mechanism.

The 'refresh' command is now synonymous with 'restart'.

Because the compiler is now written in Perl, your compile-time extension scripts from earlier versions will no longer work. 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.

When a script is invoked, the $chainref scalar variable will hold a reference to a chain table entry.

To add a rule to the chain:

Where

Example:

To insert a rule into the chain:

The log_rule_limit function works like it does in the shell compiler with two exceptions:

Example:

    log_rule_limit
              'info' , 
              $chainref , 
              $chainref->{name},
              'DROP' , 
              '',    #Limit
              '' ,   #Log tag
              'add';         

The /etc/shorewall/tos file now has zone-independent SOURCE and DEST columns as do all other files except the rules and policy files.

The SOURCE column may be one of the following:

The DEST column may be one of the following:

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.

Currently, support for ipsets is untested. That will change with future pre-releases but one thing is certain -- 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.

So:

As a consequence, scripts generated by the Perl-based compiler will ignore /etc/shorewall/ipsets and will issue a warning if you set SAVE_IPSETS=Yes in shorewall.conf.

Because the configuration files (with the exception of /etc/shorewall/params) 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.

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.

DELAYBLACKLISTLOAD=Yes is not supported. The entire ruleset is atomically loaded with one execution of iptables-restore.

MAPOLDACTIONS=Yes is not supported. People should have converted to using macros by now.

The pre Shorewall-3.0 format of the zones file is not supported; neither is the /etc/shorewall/ipsec file.