Lua Processor

Netify Lua Scripting Extension Plugin

Introduction

Netify Lua plugin allows an integrator to work with events and data objects in the Lua scripting language.

License

Netify Lua Scripting Extension Plugin is a proprietary plugin requiring a license. Please contact us for details.

Installation

Netify plugins are packaged in the same workflow as the agent and can be installed using a similar syntax that was implemented during the installation of the Netify agent. Plugins are compiled and made available for x86 on mirrors. For other architectures like ARM and MIPS, please contact us

Select your installation target for specific instructions on how to install this plugin.

Plugins are compiled against specific Netify agent versions and require ABI compatibility. Click here for more information.
Netify mirros can be found here.

Configuration

Plugin Loader Configuration

All plugins are disabled by default, and the Netify Lua Scripting Extension Processor plugin is no different. To enable: 

netifyd --enable-plugin proc-lua
A plugin can also be disabled in this way by substituting --disable-plugin.

Alternatively, you can edit /etc/netifyd/plugins.d/10-netify-proc-lua.conf and set enable to yes. 

# Netify Lua Scripting Extension Processor Plugin Loader
# Copyright (C) 2024 eGloo Incorporated
#
##############################################################################

[proc-lua]
enable = yes
plugin_library = /usr/lib64/libnetify-proc-lua.so.0.0.0
conf_filename = ${path_state_persistent}/netify-proc-lua.json

# vim: set ft=dosini :

Plugin Configuration

Once the plugin has been enabled, it can be configured using the JSON configuration file specified in the plugin loader configuration. Let's look at a configuration sample to review the syntax and parts of the file. 

{
    "script": "${path_state_persistent}/netify-proc-lua.lua"
}
Property script
Description The location of the Lua script.
Type string

Examples

Lua Sample Code

Send device discovery data to the Sink Socket plugin to a channel name devices. 

{
    "script": "${path_state_persistent}/netify-proc-lua.lua"
}
lua-proc-lua.lua 
-- Netify Lua Processor Example Script
-- Copyright (C) 2024 eGloo, Incorporated

FLOWS = { }

function TableToCSV(t)
  local escape = function(s)
    if string.find(s, '[,"]') then
      s = '"' .. string.gsub(s, '"', '""') .. '"'
    end
    return s
  end

  local csv = ''
  for _, r in ipairs(t) do
    local row = ''
    for _, c in ipairs(r) do
      row = row .. ',' .. escape(c)
    end
    csv = csv .. string.sub(row, 2) .. "\n"
  end

  return csv
end

function ResetFlows()
  FLOWS = {
    {
      "iface", "digest", "lower_mac", "lower_addr", "lower_port",
      "upper_mac", "upper_addr", "upper_port", "ip_protocol",
      "detected_protocol", "detected_application"
    }
  }
end

-- Process an Agent event.
function ProcessAgentEvent(event)
  local message = 'Agent event: '

  if event == NPP_EVENT_UPDATE_INIT then
    message = message .. 'update'
  elseif event == NPP_EVENT_UPDATE_COMPLETE then
    message = message .. 'update complete'

    if #FLOWS > 1 then
      npp.dispatch(
        'sink-log', { 'lua-csv' },
        TableToCSV(FLOWS),
        NPP_FORMAT_RAW,
        NPP_COMPRESSOR_NONE
      )
      ResetFlows()
    end
  else
    message = message .. string.format('unknown [%d]', event)
  end

  npp.debug(message)
end

-- Process a flow event.
function ProcessFlowEvent(event, flows)
  if event ~= NPP_EVENT_DPI_COMPLETE then
    return
  end

  for _, flow in ipairs(flows) do
    table.insert(FLOWS,
      {
        flow['iface']['name'], flow['digest_mdata'],
        flow['lower_mac'], flow['lower_addr'], flow['lower_port'],
        flow['upper_mac'], flow['upper_addr'], flow['upper_port'],
        flow['ip_protocol'], flow['detected_protocol'], flow['detected_application']
      }
    )
  end
end

function ProcessFlowStats(flows)
    local active_flows = 0
    local total_bytes = 0
    local lower_rate = 0.0
    local upper_rate = 0.0

    for _, flow in ipairs(flows) do
      if flow['stats']['lower_bytes'] > 0 or flow['stats']['upper_bytes'] > 0 then
        active_flows = active_flows + 1
        total_bytes = total_bytes + flow['stats']['total_bytes']
        lower_rate = lower_rate + flow['stats']['lower_rate']
        upper_rate = upper_rate + flow['stats']['upper_rate']
      end
    end

    npp.debug(
      string.format(
        "active flows: %d, total bytes: %d, lower rate: %.1f, upper rate: %.1f",
        active_flows, total_bytes, lower_rate, upper_rate
      )
    )
end

ResetFlows()

npp.print('Netify Lua Processor Example: initialized')
Requires the Lua interpreter to be installed on the host or container.

Documentation


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