mapper to check domain of IP

domain_mapper.rb

#!/usr/bin/env ruby
require 'socket'
ARGF.each do |line|

   line = line.chomp
   data = line.split(/\t/)
   ip = data[0]
   
   # resolve IP to hostname and split by '.'
   hostname=Socket.getnameinfo([nil, nil, nil, ip])[0]
   d=hostname.split('.')
   
   if ip == hostname # IP was not resolved to hostname
     if d[0] == "10"
       domain = "*.*.*.10" # assume 10.0.0.0/8 as 10.*.*.*
     else
       domain = ['*',d[2],d[1],d[0]].join(".")
     end
   else
     tld=d.last
     secd=d[d.length-2]
     thrd=d[d.length-3]
     
     # check if it is TLD/generic jp domain or not
     if tld =~/^(com|net|org|info|biz|name|pro|aero|coop|museum|jobs|travel|mail|cat|post|asia|mobi|tel|xxx)$/
       domain = [tld,secd].join(".")
     elsif d.last == "jp" && ( secd.length > 2)
       domain = [tld,secd].join(".")
     else
       domain = [tld,secd,thrd].join(".")
     end
   end

   key = domain.split(".").reverse.join(".")
  
   value = data[1]

   # output to STDOUT
   #
   puts key + "\t" + value.to_s

end