#!/usr/bin/env ruby
#
# Wildcard-script to monitor network port usage using netstat. To monitor a
# port, link port_<service> to this file. E.g. This plugin shall run by root user
#
#    ln -s /usr/share/munin/node/plugins-auto/port_ /etc/munin/node.d/port_www
#
# ...will monitor www connections. Services are those listed in
# /etc/services. Case service is not listed the numeric value shall be passed
#
# Author: Luis García Acosta
# V 1.0
# Date Tue April 12 09:20:21 CET 2011

require 'rubygems'
require 'munin'

SERVICE   = $0.split( '_' ).last
SERVICE_F = '/etc/services'
PORT      = /^[\d]+(\.[\d]+){0,1}$/ === SERVICE ? SERVICE : %x[grep #{SERVICE} #{SERVICE_F}].split( "\t\t" )[1].split( '/' )[0]

class PortMonit < Munin::Plugin

  graph_attributes "#{SERVICE} port usage, known as #{PORT}",
    :category   => 'network',
    :info       => 'This graph shows connection split by the state of the socket.',
    :vlabel     => 'Current connections'

   declare_field :ESTABLISHED,
    :label  => 'Established',         :draw => :AREA,
    :type   => :GAUGE, :min => 0

   declare_field :CLOSE_WAIT,
    :label  => 'Waiting close',       :draw => :STACK,
    :type   => :GAUGE, :min => 0

   declare_field :TIME_WAIT,
    :label  => 'Waiting after close', :draw => :STACK,
    :type   => :GAUGE, :min => 0

   declare_field :CLOSING,
    :label  => 'Closing',             :draw => :STACK,
    :type   => :GAUGE, :min => 0

   declare_field :LAST_ACK,
    :label  => 'Waiting for acknowledgement',   :draw => :STACK,
    :type   => :GAUGE, :min => 0

   declare_field :FIN_WAIT_1,
    :label  => 'Socket closed, connection shutting down', :draw => :STACK,
    :type   => :GAUGE, :min => 0

   declare_field :FIN_WAIT_2,
    :label  => 'Connection closed, Socket still waiting', :draw => :STACK,
    :type   => :GAUGE, :min => 0

  def retrieve_values
   
    @_netstat   = %x[netstat -n -P tcp | egrep "\.#{PORT} "].split( "\n" )


    { :ESTABLISHED  => count( @_netstat, 'ESTABLISHED' ),
      :CLOSE_WAIT   => count( @_netstat, 'CLOSE_WAIT' ),
      :CLOSING      => count( @_netstat, 'CLOSING' ),
      :LAST_ACK     => count( @_netstat, 'LAST_ACK' ),
      :FIN_WAIT_1   => count( @_netstat, 'FIN_WAIT_1' ),
      :FIN_WAIT_2   => count( @_netstat, 'FIN_WAIT_2' ),
      :TIME_WAIT    => count( @_netstat, 'TIME_WAIT' ) }
  end

  private
  def count( source, regex )
    @_result = 0

    source.each { |obj| @_result += 1 if obj.match( regex ) }
    
    return @_result
  end
end

PortMonit.new.run