Shorewall-pl 3.9.0

This companion product to Shorewall 3.4.2 and later includes a complete
rewrite of the compiler in Perl.

Shorewall-pl depends on Shorewall (3.4.2 or later). So if you want to use the
new compiler, you must install both Shorewall and Shorewall-pl.

Even if you install Shorewall-pl, you have a choice of which compiler you use.
The choice is specified in the shorewall.conf file so you can select the
compiler to use on a system-by-system basis when running Shorewall Lite on
remote systems.

I decided to make Shorewall-pl a separate product for several reasons:

a) Embedded applications are unlikely to adopt Shorewall-pl; even Mini-Perl
has a substantial disk and Ram footprint.

b) Because of the gross incompatibilities between the new compiler and the
old (see below), migration to the new compiler must be voluntary.

c) By allowing Shorewall-pl to co-exist with the current Shorewall stable
release (3.4), I'm hoping that the new compiler will get more testing and
validation than it would if I were to package it with a new development
version of Shorewall itself.

d) Along the same vein, I think that users will be more likely to experiment
with the new compiler if they can easily fall back to the old one if things
get sticky.

The good news:

a) The compiler is small.
b) The compiler is very fast.
c) The compiler generates a firewall script that uses iptables-restore;
so the script is very fast.
d) Use of the perl compiler is optional! The old slow clunky
   Bourne-shell compiler is still available.

The bad news:

There are a number of incompatibilities between the Perl-based compiler
and the Bourne-shell one.

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

   - addrtype match
   - conntrack match
   - extended multiport match

   These capabilities are in current distributions.

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

c) The BROADCAST column in the interfaces file is essentailly unused;
   if you enter anything in this column but '-' or 'detect', you will
   receive a warning.

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

e) The 'refresh' command is now synonamous with 'restart'.

f) Some run-time extension scripts are no longer supported because they
   make no sense (iptables-restore instantiates the new configuration
   atomically).

	continue
	initdone
	continue
	refresh
	refreshed

g) Currently, support for ipsets is untested. That will change with
   future releases but one thing is certain -- Shorewall is now out of the
   ipset load/reload business. If the Netfilter ruleset is never cleared,
   then there is no opportunity for Shorewall to load/reload your
   ipsets.

   So:
	
	i)   Your ipsets must be loaded before Shorewall starts.
	
	ii)  Your ipsets may not be reloaded until Shorewall is stopped or
	     cleared.

	iii) If you specify ipsets in your routestopped file then
	     Shorewall must be cleared in order to reload your ipsets.

   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.

Installation
------------

1) Unpack the tarball.

   $ tar -jxf shorewall-pl-3.9.0-1.tar.bz2
   $ pwd
   /home/teastep/shorewall/
   $ ls
   shorewall-pl-3.9.0/
   $

2) As root, create a symbolic link to the directory containing the unpacked
   files.

   $ ln -sf /home/teastep/shorewall/ /usr/share/shorewall-pl

Using the New compiler
----------------------

By default, the old Bourne-shell based compiler will be used. 

There is one change in Shorewall operation that is triggered when
/usr/share/shorewall-pl exists and is either a directory or a symbolic
link that points to a directory: Your params file will be processed
with the shell's '-a' option set which will automatically export any
variables that you set or create.

To actually use the new compiler, add this to shorewall.conf:

   SHOREWALL_PL=Yes

If you add this setting to /etc/shorewall/shorewall.conf then by
default, the new compiler will be used on the system. If you add it to
shorewall.conf 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.