From: Peter Ertl <pertl@...>
Date: 2006-04-21T02:08:11+09:00
Subject: Re: Converting IP range to array of IP's

the code it's broken / working fine depending on how you define a range...

lets say you have a 192.168.0.0/10 subnet:

192.168.0.1 - 192.168.3.254

will do a 'wraparound' and emit addresses like

192.168.1.0 (which is a subnet but no host)
192.168.1.255 (which is the broadcast)

but these are not legal ip addresses.

this is inconvenient if you want to address all hosts in a subnet

I would define range in our case:

"all ips between ip1 and ip2 where _each_ of the digits is between the
corresponding digit in ip1 and ip2"

example:
192.168.1.3 - 192.168.2.4:

[192, 168, 1, 3]
[192, 168, 1, 4]
[192, 168, 2, 3]
[192, 168, 2, 4]




> --- Urspr�ngliche Nachricht ---
> Von: "Paul Battley" <pbattley@gmail.com>
> An: ruby-talk@ruby-lang.org (ruby-talk ML)
> Betreff: Re: Converting IP range to array of IP's
> Datum: Fri, 21 Apr 2006 01:52:27 +0900
> 
> On 20/04/06, Kris <krisleech@interkonect.com> wrote:
> > I'm looking to convert an IP string (ranges, subnet masks or wild-carded
> > IP's) in to an array of IP strings:
> 
> The dotted notation is just a human-readable version of a 32-bit
> value, so you can do this:
> 
> def dq_to_int(dq)
>   parts = dq.split('.').map{ |s| s.to_i }.reverse
>   (0..3).inject(0){ |r,i| r + parts[i] * (0x100**i) }
> end
> 
> def int_to_dq(int)
>   (0..3).map{ |i| ((int / (0x100**(3-i))) & 0xFF).to_s }.join('.')
> end
> 
> (dq_to_int('192.168.1.1')..dq_to_int('192.168.1.5')).map{ |i| int_to_dq(i)
> }
> # => ["192.168.1.1", "192.168.1.2", "192.168.1.3", "192.168.1.4",
> "192.168.1.5"]
> 
> Paul.