Re: [B.A.T.M.A.N.] [PATCH 1/5] batman-adv: Use common Jenkins Hash implementation

[Antonio Quartulli <ordex@autistici.org>]

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On Mon, Nov 26, 2012 at 01:39:00PM +0100, Sven Eckelmann wrote:
> On Monday 26 November 2012 13:30:02 Antonio Quartulli wrote:
> [...]
> > > The in kernel implementation will create a different hash sum -> tt
> > > entries
> > > will end up in a different bucket -> CRC will be different (please correct
> > > me about the last step... just had this problem in the back of my head).
> > CRC computation does not rely on entries positions, because the real CRC16
> > is computed on the client mac address only (and this is the same
> > everywhere) then the results are XOR'd together. Since XOR is commutative
> > we do not need to keep the same order network wide.
> 
> I've already wrote this two 2 1/2 hours ago.
> 
> > Instead, your reasoning is correct for DAT, but for the global DAT hash
> > function only.
> > The local one can be whatever we need, so we can also use jhash for this.
> 
> Please define global and local DAT hash function. Because you use the same 
> function in both places.

Yes, sorry, it's my fault. At the very beginning DAT had two distinct hash
functions (before it got merged) but then I decided to use the same everywhere.

At this point I would rather suggest to leave DAT as it is (so v2 it's fine with
me).


Thank you.

Cheers,



-- 
Antonio Quartulli

..each of us alone is worth nothing..
Ernesto "Che" Guevara

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