Subject: Re: Question about tcp hash function tcp_hashfn()

From: Evgeniy Polyakov <[email-masked]>
Date: Thu, 1 Jun 2006 10:30:13 +0400

On Thu, Jun 01, 2006 at 12:18:25AM -0600, Brian F. G. Bidulock ([email-masked]) wrote:
> Evgeniy,
> 
> On Thu, 01 Jun 2006, Evgeniy Polyakov wrote:
> > 	
> > 	for (i=0; i<hash_size*iter_num; ++i) {
> > 		saddr = num2ip(get_random_byte(), get_random_byte(), get_random_byte(), get_random_byte());
> > 		sport = get_random_word();
> 
> You still have a problem: you cannot use a pseudo-random number
> generator to generate the sample set as the pseudo-random number
> generator function itself can interact with the hash.
> 
> Try iterating through all 2**48 values or at least a sizeable
> representative subset.

Since pseudo-randomness affects both folded and not folded hash
distribution, it can not end up in different results.

You are right that having test with 2^48 values is really interesting,
but it will take ages on my test machine :)

-- 
	Evgeniy Polyakov