check_nf_conntrack.rb

#!/usr/bin/ruby
#TH v0.1 10/09/2014
#check nf_contrack_table usage script

require 'rubygems'
require 'snmp'

class SNMP_check
   attr_reader :responce

  def initialize (host, community, crit, warn)
    @host = host
    @community = community
    @crit = crit.to_f
    @warn = warn.to_f
  end

  def poll
    begin
      SNMP::Manager.open(:host => @host, :Community => @community) do |pollServer|
        (nf_max, nf_count) = \
        pollServer.get_value ["1.3.6.1.4.1.8072.1.3.2.3.1.1.16.110.102.95.99.111.110.110.116.114.97.99.107.95.109.97.120",
                              "1.3.6.1.4.1.8072.1.3.2.3.1.1.18.110.102.95.99.111.110.110.116.114.97.99.107.95.99.111.117.110.116"]
        @responce = (nf_count.to_f/nf_max.to_f) * 100
      end
    rescue
      print("SNMP problem. No data received from host.\n")
      exit 3
    end
  end

  def check
    if @responce > @crit
      printf("Contrack Critical - " "%.02f", "#@responce")
      print "%\n"
      exit 2
    elsif @responce < @crit and @responce > @warn
      printf("Contrack Warning - " "%.02f", "#@responce")
      print "%\n"
      exit 1
    else
      printf("Contrack Ok - " "%.02f", "#@responce")
      print "%\n"
      exit 0
    end
  end

end

host = ARGV[0]
community = ARGV[1]
warn = ARGV[2].to_i
crit = ARGV[3].to_i

if ARGV.length < 1
puts "Usage: host community warn critical"
elsif crit <= warn
  puts "Warning must be less than critical"
  exit 3
elsif
  crit > 100
  puts "Critical should be less than 100%"
else
  server = SNMP_check.new(host, community, crit, warn)
  server.poll
  server.check
end