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From: Pablo Neira Ayuso <pablo@netfilter.org>
To: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Cc: Hans Schillstrom <hans.schillstrom@ericsson.com>,
	Eric Dumazet <eric.dumazet@gmail.com>,
	Jan Engelhardt <jengelh@inai.de>,
	"kaber@trash.net" <kaber@trash.net>,
	"jengelh@medozas.de" <jengelh@medozas.de>,
	"netfilter-devel@vger.kernel.org"
	<netfilter-devel@vger.kernel.org>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"dan.carpenter@oracle.com" <dan.carpenter@oracle.com>,
	"hans@schillstrom.com" <hans@schillstrom.com>
Subject: Re: [PATCH] netfilter: xt_HMARK: endian bugs
Date: Mon, 14 May 2012 21:02:11 +0200	[thread overview]
Message-ID: <20120514190211.GC14897@1984> (raw)
In-Reply-To: <alpine.DEB.2.00.1205142032570.28548@blackhole.kfki.hu>

On Mon, May 14, 2012 at 08:35:26PM +0200, Jozsef Kadlecsik wrote:
> On Mon, 14 May 2012, Hans Schillstrom wrote:
> 
> > On Monday 14 May 2012 18:24:34 Eric Dumazet wrote:
> > > On Mon, 2012-05-14 at 18:09 +0200, Hans Schillstrom wrote:
> > > 
> > > > This context can contain both le & be machines,
> > > > so at least in hmark it make sense
> > > 
> > > Before jhash() and its shuffle ? What do you mean ?
> > 
> > I want that a Big endian machine should produce the same
> > hash value independent of flow direction as a Little endian.
> > 
> > OK, I missed ntohl() before calling jhash_3words()
> > 
> > Correct me if I'm wrong here (have no big endian machine available for test)
> > jhash_3words() and __jhash_final() seems to be "endian" safe.
> 
> No, but as Eric wrote: what is the point in forcing the same hash value 
> for the same input on big endian and little endian machines? Are you going 
> to transfer the hash value between machines?

IIRC, Hans wants that, in case you have a cluster composed of system
with different endianess, the hash mark calculated will be the same
in both systems. To ensure that the distribution is consistent with
independency of the endianess.

  reply	other threads:[~2012-05-14 19:02 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-14 13:42 [PATCH] netfilter: xt_HMARK: endian bugs Hans Schillstrom
2012-05-14 14:40 ` Pablo Neira Ayuso
2012-05-14 15:05   ` Hans Schillstrom
2012-05-14 15:05   ` Jan Engelhardt
2012-05-14 15:24     ` Eric Dumazet
2012-05-14 16:09       ` Hans Schillstrom
2012-05-14 16:24         ` Eric Dumazet
2012-05-14 17:51           ` Hans Schillstrom
2012-05-14 18:24             ` Jan Engelhardt
2012-05-14 18:28             ` Eric Dumazet
2012-05-14 18:35             ` Jozsef Kadlecsik
2012-05-14 19:02               ` Pablo Neira Ayuso [this message]
2012-05-14 19:13                 ` Eric Dumazet
2012-05-15  5:57                   ` Hans Schillström
2012-05-15  7:33       ` Hans Schillström

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