From: Eric Dumazet <dada1@cosmosbay.com>
To: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
Cc: David Miller <davem@davemloft.net>,
nikb@webmaster.com, netdev@vger.kernel.org
Subject: Re: RFC: Established connections hash function
Date: Fri, 23 Mar 2007 09:17:19 +0100 [thread overview]
Message-ID: <46038D0F.1060507@cosmosbay.com> (raw)
In-Reply-To: <20070323080715.GB29991@2ka.mipt.ru>
Evgeniy Polyakov a ecrit :
> Call me a loooser which mail will be deleted on arrival, but...
>
> jhash_2words(const, const, ((const << 16) | $sport) ^ $random)
>
> where $sport is 1-65535 in a loop, and $random is pseudo-random number
> obtained on start.
>
> Which is exactly the case of web server and attacker connects to 80 port
> from the same IP address and different source ports.
>
> Result with jenkins:
> 1 23880
> 2 12108
> 3 4040
> 4 1019
> 5 200
> 6 30
> 7 8
> 8 1
>
> Xor:
> 1 65536
So what ? You still think hash function must be bijective ? Come on !
You have a machine somewhere that allows 65536 concurrent connections coming
from the same IP address ?
The last problem you have is the nature of tcp hash function.
Dont argue again with your pseudo science.
next prev parent reply other threads:[~2007-03-23 8:17 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-03-22 15:39 RFC: Established connections hash function Nikolaos D. Bougalis
2007-03-22 15:52 ` Evgeniy Polyakov
2007-03-22 17:32 ` Nikolaos D. Bougalis
2007-03-22 18:21 ` Evgeniy Polyakov
2007-03-22 19:44 ` Nikolaos D. Bougalis
2007-03-22 19:56 ` Evgeniy Polyakov
2007-03-22 20:53 ` Nikolaos D. Bougalis
2007-03-23 7:52 ` Evgeniy Polyakov
2007-03-22 20:58 ` David Miller
2007-03-22 22:03 ` Eric Dumazet
2007-03-23 7:11 ` David Miller
2007-03-23 8:00 ` Eric Dumazet
2007-03-23 18:46 ` David Miller
2007-03-23 8:07 ` Evgeniy Polyakov
2007-03-23 8:17 ` Eric Dumazet [this message]
2007-03-23 8:33 ` Evgeniy Polyakov
2007-03-23 9:10 ` Evgeniy Polyakov
2007-03-23 11:58 ` XOR hash beauty solved [Was: RFC: Established connections hash function] Evgeniy Polyakov
2007-03-23 12:51 ` Nikolaos D. Bougalis
2007-03-23 12:45 ` RFC: Established connections hash function Nikolaos D. Bougalis
2007-03-27 14:11 ` Andi Kleen
2007-03-28 5:01 ` Nikolaos D. Bougalis
2007-03-28 6:29 ` David Miller
2007-03-28 9:29 ` Andi Kleen
2007-03-28 10:45 ` Evgeniy Polyakov
2007-03-28 14:14 ` Andi Kleen
2007-03-28 13:50 ` Eric Dumazet
2007-03-28 14:52 ` Andi Kleen
2007-03-29 9:18 ` Evgeniy Polyakov
2007-03-28 14:17 ` RFC: Established connections hash function II Andi Kleen
2007-03-28 19:04 ` RFC: Established connections hash function David Miller
2007-03-28 20:12 ` Andi Kleen
-- strict thread matches above, loose matches on Subject: below --
2007-03-24 12:26 linux
2007-03-24 13:29 ` Evgeniy Polyakov
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