From: David Miller <davem@davemloft.net>
To: douglascs@taghos.com.br
Cc: sergei.shtylyov@cogentembedded.com, kuznet@ms2.inr.ac.ru,
jmorris@namei.org, yoshfuji@linux-ipv6.org, kaber@trash.net,
netdev@vger.kernel.org
Subject: Re: [PATCH v3] tcp: fix wrong checksum calculation on MTU probing
Date: Fri, 23 Sep 2016 07:58:39 -0400 (EDT) [thread overview]
Message-ID: <20160923.075839.1436905982520228085.davem@davemloft.net> (raw)
In-Reply-To: <f920ce68-c4e9-7772-809c-01f7319fa78e@taghos.com.br>
From: Douglas Caetano dos Santos <douglascs@taghos.com.br>
Date: Thu, 22 Sep 2016 15:52:04 -0300
> With TCP MTU probing enabled and offload TX checksumming disabled,
> tcp_mtu_probe() calculated the wrong checksum when a fragment being copied
> into the probe's SKB had an odd length. This was caused by the direct use
> of skb_copy_and_csum_bits() to calculate the checksum, as it pads the
> fragment being copied, if needed. When this fragment was not the last, a
> subsequent call used the previous checksum without considering this
> padding.
>
> The effect was a stale connection in one way, as even retransmissions
> wouldn't solve the problem, because the checksum was never recalculated for
> the full SKB length.
>
> Signed-off-by: Douglas Caetano dos Santos <douglascs@taghos.com.br>
Applied and queued up for -stable, thanks.
prev parent reply other threads:[~2016-09-23 11:58 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-19 21:16 [PATCH] tcp: fix wrong checksum calculation on MTU probing Douglas Caetano dos Santos
2016-09-21 2:57 ` David Miller
2016-09-21 18:26 ` [PATCH v2] " Douglas Caetano dos Santos
2016-09-22 11:12 ` Sergei Shtylyov
2016-09-22 18:52 ` [PATCH v3] " Douglas Caetano dos Santos
2016-09-23 11:58 ` David Miller [this message]
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