RADIUS Lua Service

Introduction

The RadiusLuaService is a service for initiating Lua scripts running within the LogicApp.

The RadiusLuaService receives messages from one or more instances of the RadiusApp which is configured to receive RADIUS Requests from an external client.

The RadiusLuaService communicates with the RadiusApp using the RADIUS-S-… messages.

Configuring RadiusLuaService

The RadiusLuaService is configured within a LogicApp.

    <?xml version="1.0" encoding="utf-8"?>
    <n2svcd>
      ...
      <applications>
        ...
        <application name="Logic" module="LogicApp">
          <include>
            <lib>../apps/logic/lib</lib>
          </include>
          <parameters>
            ...
          </parameters>
          <config>
            <services>
              <service module="RadiusApp::RadiusLuaService" libs="../apps/radius/lib" script_dir="/var/lib/n2svcd/logic/radius"/>
            </services>
            <agents>
              ...
            </agents>
          </config>
        </application>
        ...
      </application>
      ...
    </n2svcd>

In addition to the Common LogicApp Service Configuration, note the following specific attribute notes, and service-specific attributes.

Under normal installation, the following service attributes apply:

Script Selection (RADIUS Request)

Script selection is not configured. The script name is simply the name or code associated with the packet type of the received RADIUS request.

e.g. an inbound Access-Request packet will be satisfied by a file named Access-Request.lua in the script_dir directory configured for the service.

Refer to the LogicApp configuration for more information on directories, library paths, and script caching parameters.

Script Global Variables

Scripts run with this service have access to the Common LUA Service Global Variables.

There are no service-specific global variables.

Script Entry Parameters (RADIUS Request)

The Lua script must be a Lua chunk such as the following:

local n2svcd = require "n2.n2svcd"

local radius = ...

n2svcd.debug ("Echo Supplied RADIUS Inputs:")
n2svcd.debug_var (radius)

-- Echo back all of the received attributes with a custom attribute appended.
radius.attributes.insert ({ type = 42, data_type = 'integer', value = 42 })

return radius

The chunk will be executed with a single radius entry parameter which is an object representing the received request, with the following attributes:

Script Return Parameters (RADIUS Response)

The Lua script is responsible for determing the RADIUS Response which will be sent back in reply to the original RADIUS Request.

The simplest way to do this is by the return value given back to the service at the end of script execution.

To indicate that no response should be sent, the script should return an empty table.

To send a response, the script should return a table containing the following attributes.

Example (returning RADIUS Response arguments):

local n2svcd = require "n2.n2svcd"

local radius = ...

return {
    name = "Access-Accept",
    attributes = {
      { name = "Service-Type", value_name = "Framed" },
      { name = "Custom-1", type = 42, data_type = "Integer", value = 789 }
    }
}

The RadiusLuaService API

The RADIUS Service API can be loaded as follows.

    local radius_service_api = require "n2.n2svcd.radius_service"

It is not necessary to load the RADIUS Service API if you are only using the simple response mechanism described above. It is only required if you wish to use any of the early response functions described below.

A chunk should return nil after an early response. The actual return result is ignored in that scenario.

.response

When a Lua Script needs to perform extended processing, it may wish to send an early RADIUS response before the script completes. This can be done with the response method on the RADIUS Service API.

The response method accepts the following parameters.

The response method returns true.

[Fragment] Example (Early Response):

    ...
    radius_service_api.response (
      "Access-Accept",
      {
        { name = "Service-Type", value_name = "Framed" },
        { name = "Custom-1", type = 42, data_type = "Integer", value = 789 }
      }
    )
    ...
    [post-processing after RADIUS transaction is concluded]
    ...

    return nil

.no_response

When a Lua Script needs to perform extended processing, it may wish to discard the RADIUS request before the script completes. This can be done with the no_response method on the RADIUS Service API.

The no_response method has no parameters.

The no_response method returns true.

[Fragment] Example (Early No-Response):

    ...
    radius_service_api.no_response ()
    ...
    [post-processing after RADIUS transaction is concluded]
    ...

    return nil