From: David Miller <davem@davemloft.net>
To: eric.dumazet@gmail.com
Cc: netdev@vger.kernel.org, ncardwell@google.com, ycheng@google.com
Subject: Re: [PATCH] ipv6: use a stronger hash for tcp
Date: Thu, 21 Feb 2013 18:18:22 -0500 (EST) [thread overview]
Message-ID: <20130221.181822.1234155083700257175.davem@davemloft.net> (raw)
In-Reply-To: <1361485132.17413.19.camel@edumazet-glaptop>
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Thu, 21 Feb 2013 14:18:52 -0800
> From: Eric Dumazet <edumazet@google.com>
>
> It looks like its possible to open thousands of TCP IPv6
> sessions on a server, all landing in a single slot of TCP hash
> table. Incoming packets have to lookup sockets in a very
> long list.
>
> We should hash all bits from foreign IPv6 addresses, using
> a salt and hash mix, not a simple XOR.
>
> inet6_ehashfn() can also separately use the ports, instead
> of xoring them.
>
> Reported-by: Neal Cardwell <ncardwell@google.com>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
Applied, and queued up for -stable, thanks Eric.
I bet we can consolidate this slightly, to make it less
expensive yet not give up much in terms of protection. Two
jhash3word()'s is quite a lot.
next prev parent reply other threads:[~2013-02-21 23:18 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-21 22:18 [PATCH] ipv6: use a stronger hash for tcp Eric Dumazet
2013-02-21 22:43 ` Hannes Frederic Sowa
2013-02-21 22:48 ` Eric Dumazet
2013-02-21 23:06 ` Hannes Frederic Sowa
2013-02-21 23:18 ` David Miller [this message]
2013-02-21 23:49 ` Andi Kleen
2013-02-22 0:14 ` Hannes Frederic Sowa
2013-02-22 0:48 ` David Miller
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