Ruby port of range2cidr. Convert IP ranges to set of CIDR.

sevkin (Vsevolod Balashov) — Wed, 11 Apr 2007 19:32:53 GMT

See rfc1878 for more detail about CIDR



#!/usr/bin/env ruby

# -*- coding: utf-8 -*-

# $Hg: range_cidr.rb,v af9566d89389 2007-04-12 20:28 +0400 $

# (C) 2007 under terms of LGPL v2.1

# by Vsevolod S. Balashov 

#

# backported from perl code

# http://www.irbs.net/internet/postfix/0401/att-3032/cidr_range.pl.gz



def range_cidr(first, last, &block)

  if first < last

    idx1 = 32

    idx1 -= 1 while first[idx1] == last[idx1]

    prefix = first >> idx1+1 << idx1+1



    idx2 = 0

    idx2 += 1 while idx2 <= idx1 and first[idx2] == 0 and last[idx2] == 1



    if idx2 <= idx1

      range_cidr(first, prefix | 2**idx1-1, &block)

      range_cidr(prefix | 1 << idx1, last, &block)

    else

      yield prefix, 32-idx2

    end

  else

    yield first, 32

  end

end

Example Usage



#!/usr/bin/env ruby

# $Hg: range2cidr.rb,v 2142c33ada8b 2007-04-11 23:14 +0400 $

# (C) 2007 under terms of GPL v2

# by Vsevolod S. Balashov 

#

# example usage of range_cidr.rb



require 'lib/range_cidr'

require 'ipaddr'

require 'socket'



if __FILE__ == $0

  if ARGV.size == 2

    range_cidr(IPAddr.new(ARGV[0]).to_i, IPAddr.new(ARGV[1]).to_i) { |subnet, mask|

      puts "#{IPAddr.new(subnet, Socket::AF_INET).to_s}/#{mask}"  }

  else

    puts "usage: range2cidr  "

    puts "example: range2cidr 192.168.1.0 192.168.2.255"

  end

end

Type in terminal and look result



$ ruby range2cidr.rb 192.168.1.0 192.168.2.255

192.168.1.0/24

192.168.2.0/24

I hate perl.

DZone Snippets: rfc code

Ruby port of range2cidr. Convert IP ranges to set of CIDR.