haproxy/contrib/spoa_example/README

A Random IP reputation service acting as a Stream Processing Offload Agent
--------------------------------------------------------------------------

This is a very simple service that implement a "random" ip reputation
service. It will return random scores for all checked IP addresses. It only
shows you how to implement a ip reputation service or such kind of services
using the SPOE.


  Start the service
---------------------

After you have compiled it, to start the service, you just need to use "spoa"
binary:

    $> ./spoa  -h
    Usage: ./spoa [-h] [-d] [-p <port>] [-n <num-workers>]
        -h                  Print this message
        -d                  Enable the debug mode
        -p <port>           Specify the port to listen on (default: 12345)
        -n <num-workers>    Specify the number of workers (default: 5)

Note: A worker is a thread.


  Configure a SPOE to use the service
---------------------------------------

All information about SPOE configuration can be found in "doc/SPOE.txt". Here is
the configuration template to use for your SPOE:

    [ip-reputation]

    spoe-agent iprep-agent
        messages check-client-ip

        option var-prefix iprep

        timeout hello      100ms
        timeout idle       30s
        timeout processing 15ms

        use-backend iprep-backend

    spoe-message check-client-ip
        args src
        event on-client-session


The engine is in the scope "ip-reputation". So to enable it, you must set the
following line in a frontend/listener section:

    frontend my-front
        ...
        filter spoe engine ip-reputation config /path/spoe-ip-reputation.conf
	....

where "/path/spoe-ip-reputation.conf" is the path to your SPOE configuration
file. The engine name is important here, it must be the same than the one used
in the SPOE configuration file.

IMPORTANT NOTE:
    Because we want to send a message on the "on-client-session" event, this
    SPOE must be attached to a proxy with the frontend capability. If it is
    declared in a backend section, it will have no effet.


Because, in SPOE configuration file, we declare to use the backend
"iprep-backend" to communicate with the service, you must define it in HAProxy
configuration. For example:

    backend iprep-backend
        mode tcp
	timeout server 1m
	server iprep-srv 127.0.0.1:12345 check maxconn 5


In reply to the "check-client-ip" message, this service will set the variable
"ip_score" for the session, an integer between 0 and 100. If unchanged, the
variable prefix is "iprep". So the full variable name will be
"sess.iprep.ip_score".

You can use it in ACLs to experiment the SPOE feature. For example:

    tcp-request content reject if { var(sess.iprep.ip_score) -m int lt 20 }

With this rule, all IP address with a score lower than 20 will be rejected
(Remember, this score is random).