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From Jayapal Reddy Uradi <jayapalreddy.ur...@citrix.com>
Subject Re: Faulty method isNetworkAWithinNetworkB ?
Date Mon, 23 Dec 2013 12:33:16 GMT
Hi Saksham,

Always the higher suffix cidr will be in lower suffix cidr.
10.1.1.0/24 will have 256 addresses and 10.1.1.0/25 will have 128 addresses[1].

/25 will be completely in /24 but not wise versa. 

The below are incorrect.
> isNetworkAWithinNetworkB("10.1.1.0/24", "10.1.1.0/25") returns true
> isNetworkAWithinNetworkB("10.1.1.0/22", "10.1.1.0/23") returns true

I think you can change isNetworkAWithinNetworkB method to compare respective ip ranges for
cidrs.

What about changing method name isNetworkACompletelyWithinNetworkB() ?

[1]https://www.dan.me.uk/ipsubnets?ip=10.1.1.0


Thanks,
Jayapal

On 13-Dec-2013, at 4:49 PM, Saksham Srivastava <saksham.srivastava@citrix.com> wrote:

> Hi,
> 
> I encountered a method isNetworkAWithinNetworkB(cidrA, cidrB) in NetUtils.java which
should return true if cidrA is a subset of cidrB.
> The method returns flawed output in many scenarios. After unittesting it I found :
> 
> isNetworkAWithinNetworkB("10.1.1.0/24", "10.1.1.0/25") returns true
> isNetworkAWithinNetworkB("10.1.1.0/25", "10.1.1.0/24") returns true
> isNetworkAWithinNetworkB("10.1.1.0/23", "10.1.1.0/22") returns true
> isNetworkAWithinNetworkB("10.1.1.0/22", "10.1.1.0/23") returns true
> 
> Due to this I am able to create VPC tiers with cidr 10.1.0.0/24 even when the VPC super
cidr has been defined as 10.1.1.0/25
> IMO the simpler/cleaner way to compare cidrs should be to compare the respective IP ranges.
I have an old patch [1] in RB which uses the IP ranges to compare 2 cidrs.
> We could leverage that to replace isNetworkAWithinNetworkB() or in case of any other
suggestions please share.
> 
> Thanks,
> Saksham
> 
> [1] https://reviews.apache.org/r/14124/diff/#index_header
> 


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