Check an IP Address agains Bogons list by turning it into an integer

bogons_check.rb

#!/usr/bin/env ruby
#
# @author: Anastas Dancha <anapsix@random.io>
# @note: This script checks given IPv4 address against Bogons list
#   by turnning IPs into integers, IP Ranges into integer ranges
#   and using integer comparison.
# @note: Bogons list is retrieved during runtime from http://www.team-cymru.org
# @note: using binary math is way cooler,
#   but integers are easier to understand.
# @note: make sure to have required gems installed
#   gem install --no-ri --no-rdoc rest-client colorize
#

require 'ipaddr'
require 'rest-client'
require 'colorize'

# Expect first argument to be an IP address
IP=ARGV[0]
unless IP
  puts "Try this: #{__FILE__} 216.252.161.5".red
  exit 1
end

# turning IP to integer for simple comparison
def ip_to_int(ip)
  ipi = 0
  ip = ip.to_s if ip.class == IPAddr
  ip.split(".").reverse.each_with_index { |v,i|
    ipi += 255**(i)*v.to_i
  }
  return ipi
end

# Sample array of some bogon IP Ranges for offline testing
BOGONS_RANGES = [
  IPAddr.new("0.0.0.0/8").to_range,
  IPAddr.new("10.0.0.0/8").to_range,
  IPAddr.new("100.64.0.0/10").to_range,
  IPAddr.new("127.0.0.0/8").to_range,
  IPAddr.new("169.254.0.0/16").to_range,
  IPAddr.new("172.16.0.0/12").to_range,
  IPAddr.new("192.0.0.0/24").to_range,
  IPAddr.new("192.0.2.0/24").to_range,
  IPAddr.new("192.168.0.0/16").to_range,
  IPAddr.new("198.18.0.0/15").to_range,
  IPAddr.new("198.51.100.0/24").to_range,
  IPAddr.new("203.0.113.0/24").to_range,
  IPAddr.new("224.0.0.0/3").to_range ]

BOGONS_INT = BOGONS_RANGES.map { |range| ip_to_int(range.first.to_s)..ip_to_int(range.last.to_s) }


# Real bogons list from Team Cymru Research NFP
REAL_BOGONS_URL    = 'http://www.team-cymru.org/Services/Bogons/fullbogons-ipv4.txt'
REAL_BOGONS_LIST   = RestClient.get(REAL_BOGONS_URL).split("\n").reject! { |v| v =~ /^#/ }
REAL_BOGONS_RANGES = REAL_BOGONS_LIST.map { |range| IPAddr.new(range).to_range }
REAL_BOGONS_INT    = REAL_BOGONS_RANGES.map { |range| ip_to_int(range.first.to_s)..ip_to_int(range.last.to_s) }

# check a suspect ip agains a given range
def within_range?(suspect,ip)
  # convert suspect to String
  suspect = suspect.to_s if suspect.class == IPAddr

  if ip.class != Range
    # convert ip to integer range if it is an IPAddr and not Range yet
    range_int = ip_to_int(ip.to_range.first.to_s)..ip_to_int(ip.to_range.last.to_s) if ip.class == IPAddr
  elsif ip.class == Range
    # confirm that ip is a Range of integers
    range_int = ip if ip.first.class == Fixnum
    # convert ip to Range of integers if it's a Range of IPAddr objects
    range_int = ip_to_int(ip.first.to_s)..ip_to_int(ip.last.to_s) if ip.first.class == IPAddr
  end

  # compare suspect with first and last integer values of integer Range
  if range_int.first <= ip_to_int(suspect) && range_int.last >= ip_to_int(suspect)
    return true # if suspect is part of ip range
  else
    return false # if suspect if outside of ip range
  end
end

# check an ip against given list
def bogon_check(ip,bogons_int_array)
  bogons_int_array.each { |range_int|
    if within_range?(ip,range_int) then
      return true
    end
    }
  return false
end

# do it
puts "Checking against simplified Bogons list.."
if bogon_check(IP,BOGONS_INT) then
  puts "#{IP} is a bogon".red
else
  puts "#{IP} is NOT a bogon".green
end

puts "\nChecking against real Bogons list.."
if bogon_check(IP,REAL_BOGONS_INT) then
  puts "#{IP} is a bogon".red
else
  puts "#{IP} is NOT a bogon".green
end

exit 0