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From: Pablo Neira Ayuso <pablo@netfilter.org>
To: Stephen Hemminger <shemminger@vyatta.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
	Patrick McHardy <kaber@trash.net>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	netdev@vger.kernel.org, davem@davemloft.net,
	netfilter-devel@vger.kernel.org
Subject: Re: [RFT] nf_contrack_udp: handle packets with padding and hwchecksum
Date: Tue, 21 Feb 2012 13:19:11 +0100	[thread overview]
Message-ID: <20120221121911.GA25258@1984> (raw)
In-Reply-To: <20120217101648.01f31fcd@nehalam.linuxnetplumber.net>

Hi Stephen,

On Fri, Feb 17, 2012 at 10:16:48AM -0800, Stephen Hemminger wrote:
> If UDP packet with extra padding is received on a device that
> does hardware checksumming (but not checking) is processed
> by netfilter conntrack, it would generate a bogus warning
> about the checksum being incorrect.
> 
> There were two possible solutions. The netfilter conntrack
> code could trim the packet, discarding the extra padding
> and adjusting the checksum. Or it can force regular
> non-offloaded checksum. This patch implements the latter
> on the principal that is better for firewall code to not
> modify the packet.

I like this approach.

> Compile tested only; haven't been able to reproduce the
> problem yet.

Let me know if I should pass this to davem once you confirm this fixes
the problem you're noticing.

      reply	other threads:[~2012-02-21 12:19 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20120130155816.GA1400@phenom.dumpdata.com>
     [not found] ` <20120130083843.160ffe5e@nehalam.linuxnetplumber.net>
     [not found]   ` <1327944148.3303.1.camel@edumazet-HP-Compaq-6005-Pro-SFF-PC>
2012-02-17 18:16     ` [RFT] nf_contrack_udp: handle packets with padding and hwchecksum Stephen Hemminger
2012-02-21 12:19       ` Pablo Neira Ayuso [this message]

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