From: Todd Benson <caduceass@...>
Date: 2008-01-16T20:01:58+09:00
Subject: Re: Problem with IPAddr

On Jan 15, 2008 11:53 PM, Bryan Richardson <btricha@gmail.com> wrote:
> Gary,
>
> Thanks for the reply.  Here's what I get when I try something else:
>
> irb(main):001:0> require 'ipaddr'
> => true
> irb(main):002:0> net_1 = IPAddr.new("192.168.0.0/16")
> => #<IPAddr: IPv4:192.168.0.0/255.255.0.0>
> irb(main):003:0> net_2 = IPAddr.new("192.168.101.0/24")
> => #<IPAddr: IPv4:192.168.101.0/255.255.255.0>
> irb(main):004:0> net_1.include?(net_2)
> => true
> irb(main):005:0> net_2.include?(net_1)
> => false
> irb(main):006:0>
>
> Makes sense I guess.  Is there any way to tell IPAddr to look at it as a
> network instead of as an address?  I have a situation where I may come
> across an address (ending in .0, so defining a network) where the netmask
> isn't given, so I assign it as a small network (say /29).  Later on I may
> come across it again, this time with the netmask defined (say /16), and I
> want to merge the first one into the second one.  Therefore, each time I add
> a new network to my database, I compare it to the existing ones to see if
> any should be merged.  Any suggestions?  Thanks!! -- BTR

You could open up IPAddr to get at the mask for comparison.

class IPAddr
  def net
    @mask_addr
  end
end

ip1 = IPAddr.new("192.168.0.0/16")
ip2 = IPAddr.new("192.168.0.0/24")

ip1.net > ip2.net # => false (which seems contradictory, but the mask
number is larger for smaller networks)
ip2.net > ip1.net #=> true

hth,
Todd