Free k n filters software for linux

Doxygen Filter project is an input filter for Doxygen enabling support for Perl code documentation.
Of course, Perl developers are used to use POD rather than some other code documentation tools.
However, most developers actually are not restricted to using one single language. Instead of using multiple code documentation systems one tends to use one tool for all - Doxygen is quite a powerful code documentation system that already has built-in support for multiple programming languages.
Unfortunately, Doxygen does not directly support Perl. Thus, Doxygen Filter has been written in order to be able to use Doxygen for generating code documentation for Perl projects, too.
Enhancements:
- This release makes huge efforts for automatically extracting namespace/class/method/function information and function argument lists of not explicitly documented entities.
- Non-Perl files are now passed as is to doxygen, or are run through appropriate filters like js2doxy or pas2dox.
- The release includes a Windows executable.

Compact Filter is a network packet filter for Linux. It features an easy-to-use compact filter representation and high performance.
The main features are: easy to use interface, compact filter representation (memory efficient), and very high performance.
A difference between CF and other firewalls, such as Netfilter, is its representation of the ruleset. In CF the user writes a filter which is then compiled and optimized in user-space. The optimized filter is then loaded into the kernel (using netlink). Consequently the in kernel packet filtering code only needs funtionality for setting up a filter and filtering packets, while the more complex code of optimizing the filter remains in user-space.
Because of the continuous increase of the bandwidth and the security threats, firewalls have to evolve towards more efficient filtering schemes. The truth is that the existing scheme does not scale so well with the combined growth of bandwidth and rulesets.
Our aim is to try another approach to perform packet filtering where we minimize the complexity of the filtering process. This result in, both, a reduction of the required CPU power to filter packets and a simpler (and smaller) kernel code. Of course, we are pushing all the smart and complex part out to the user-space, but, developing in user-space is much simpler and safer.
Enhancements:
- changed -d option to delete all filters
- added -D option to delete a specific filter
- changed default policy to permit rather than deny
- added -l option on flex to support --yylineno on older versions of flex
- new and improved install guide

Imager::Filters is an entire image filtering operations.

SYNOPSIS

use Imager;

$img = ...;

$img->filter(type=>autolevels);
$img->filter(type=>autolevels, lsat=>0.2);
$img->filter(type=>turbnoise)

# and lots of others

load_plugin("dynfilt/dyntest.so")
or die "unable to load pluginn";

$img->filter(type=>lin_stretch, a=>35, b=>200);

unload_plugin("dynfilt/dyntest.so")
or die "unable to load pluginn";

$out = $img->difference(other=>$other_img);

Filters are operations that have similar calling interface.

filter

Parameters:

type - the type of filter, see "Types of Filters".

many other possible parameters, see "Types of Filters" below.

Filter::cpp is a cpp source filter.

SYNOPSIS

use Filter::cpp ;

This source filter pipes the current source file through the C pre-processor (cpp) if it is available.

As with all source filters its scope is limited to the current source file only. Every file you want to be processed by the filter must have a

use Filter::cpp ;

near the top.

Here is an example script which uses the filter:

use Filter::cpp ;

#define FRED 1
$a = 2 + FRED ;
print "a = $an" ;
#ifdef FRED
print "Hello FREDn" ;
#else
print "Where is FREDn" ;
#endif

And here is what it will output:

a = 3
Hello FRED

This example below, provided by Michael G Schwern, shows a clever way to get Perl to use a C pre-processor macro when the Filter::cpp module is available, or to use a Perl sub when it is not.

# use Filter::cpp if we can.
BEGIN { eval use Filter::cpp }

sub PRINT {
my($string) = shift;

#define PRINT($string)
(print $string."n")
}

PRINT("Mu");

Look at Michaels Tie::VecArray module for a practical use.

Yet Another Filter Proxy project is a preforking, banner filtering, content scanning Perl proxy.



Yet Another Filter Proxy is a proxy to filter out advertising banners and malicious script code from web sites. It is written in Perl and based on an example by Randal L. Schwartz.

For performance reasons it uses preforking to spawn several processes of itself (like Apache does).

Unlike other available proxies (such as Junkbuster), it does blocking by Perl regular expressions on the site content, which allows you to block JavaScript and popups, in addition to normal ads.

Run perldoc yafp.pl for full readme!

IM-Filter is a daemon for GNU/Linux firewall hosts written in C which is able to analyze and filter the ICQ protocol. The daemon runs in userspace and fetches packets of the ICQ protocol by using the libnetfilter_queue mechanism.
IM-Filters main purpose is to run at a gateway, so all ICQ-related traffic of users in the LAN runs over IM-Filter. Nevertheless the daemon could also be used directly on end users computers. The following diagram shows, how the daemon is integrated in a GNU/Linux system.
One of the design goals of IM-Filter was modularity. So plugins for other protocols like MSN or IRC could be written easily. The source code already contains skeleton code for an IRC module.
Together with the source code, adequate iptables scripts are provided so that only packets which belong to ICQ traffic get in the netfilter queue of IM-Filter.
Main features:
Logging of messages sent via ICQ
IM-Filter is able to identify and log messages which have been sent via the ICQ protocol. These messages contain a timestamp, an IP-address, the appropriate UIN and - of course - the message itself. A logged message could look like this:
[2007-07-27 11:24:21] IP "10.0.0.1" sent following message to #123456789: "hello, this is a test"
Blacklists for messages and UINs
IM-Filter handles two different blacklists: for messages and for UINs. The message blacklist holds strings which must not occur in text messages. When such a string is detected in a message, it gets censored in the logfiles.
The UIN blacklist contains UINs of users which are not allowed to connect to the ICQ network. Those blacklists can be re-read by the daemon during runtime by sending signals.
Detection and blocking of file transfers
Since file transfers are not always welcome, they can be blocked by invoking the daemon with a specific command line argument. Then, users in the LAN can not send files to other users anymore. Beside blocking, the daemon logs file transfers. Such a log entry can look like this:
[2007-07-06 17:01:26] FILTRANSFER detected (outgoing): receiver uin: #123456789 || filename: test.txt || size: 143360B
List with currently logged in users
To be able to know which users are currently logged in, IM-Filter manages a text file which holds all necessary information. By default, the file is placed in /var/log/imfilter.users and contains IP-address and UIN of the users which are currently logged in. The file could look like this:
UIN=123456789, IP=10.0.0.1
UIN=234567890, IP=10.0.0.22
UIN=345678901, IP=10.0.0.4