=head1 NAME

dc_snoop - Distributed session cache traffic analysis


=head1 SYNOPSIS

B<dc_snoop> -listen <address> -server <address> [options]


=head1 DESCRIPTION

B<dc_snoop> runs as a transparent proxy supporting the L<distcache(8)> protocol
and (in theory) should work when inserted between any compliant tools. Ie. this
can be used to monitor cache operation requests and responses between
applications and B<dc_client>, or between B<dc_client> and B<dc_server>.

This tool is still in early stages of development and is provided very much
``as-is''. It is intended to be used by developers with access to the source
code - for now, most configurable behaviour of B<dc_snoop> is set in source
code and can not be manipulated on the command-line.


=head1 OPTIONS

=over 4

=item B<-listen> address

Configures the address on which B<dc_snoop> should listen for incoming
connections.  The syntax is that defined by the I<libnal> API.

=item B<-server> address

=item B<-connect> address

These flags are identical, and specify the address B<dc_snoop> should
transparently proxy all incoming connections to. For each connection accepted
by B<dc_snoop> (on the address specified by B<-listen>) a corresponding
connection is opened to the address specified by these flags. When either
connection is closed, B<dc_snoop> will correspondingly close the other
connection.

=item B<-h>, B<-help>, B<-?>

Any of these flags will cause B<dc_snoop> to display a brief usage summary to
the console and exit cleanly. Any other flags are ignored.

=back


=head1 EXAMPLES

This example demonstrates the use of B<dc_snoop> to monitor communications
between an instance of B<dc_client> and B<dc_server> both running on the same
machine using only unix domain sockets. Suppose the tools are started and tested
using the following commands;

    # Start services
    dc_server -daemon -listen UNIX:/tmp/cacheserver
    dc_client -deamon -listen UNIX:/tmp/cacheclient \
              -server UNIX:/tmp/cacheserver
    # Run some tests
    dc_test -connect UNIX:/tmp/cacheclient

The following modification should be functionally equivalent (ignoring the
additional latency and overhead of B<dc_snoop>'s involvement) and should
generate a log file of all cache transactions to I<logfile>. Note the change to
the B<-server> flag in B<dc_client>;

    # Start services
    dc_server -daemon -listen UNIX:/tmp/cacheserver
    dc_client -deamon -listen UNIX:/tmp/cacheclient \
              -server UNIX:/tmp/cachesnoop
    # Start dc_snoop logging to logfile in the background
    dc_snoop -listen UNIX:/tmp/cachesnoop \
             -server UNIX:/tmp/cacheserver > logfile &
    # Run some tests
    dc_test -connect UNIX:/tmp/cacheclient


=head1 BUGS

This program is incomplete and not at all configurable on the command-line.


=head1 SEE ALSO

=over 4

=item L<dc_client(1)>

Distributed caching client proxy.

=item L<dc_server(1)>

Distributed cache server.

=item L<distcache(8)>

Overview of the distcache architecture.

=item F<http://www.distcache.org/>

Distcache home page.

=back


=head1 AUTHOR

This toolkit was designed and implemented by Geoff Thorpe for Cryptographic
Appliances Incorporated. Since the project was released into open source, it
has a home page and a project environment where development, mailing lists, and
releases are organised. For problems with the software or this man page please
check for new releases at the project web-site below, mail the users mailing
list described there, or contact the author at F<geoff@geoffthorpe.net>.

Home Page: F<http://www.distcache.org>