From: Fan Du <fan.du@windriver•com>
To: Neil Horman <nhorman@tuxdriver•com>, <steffen.klassert@secunet•com>
Cc: <vyasevich@gmail•com>, <davem@davemloft•net>, <netdev@vger•kernel.org>
Subject: Re: [PATCH net] {xfrm, sctp} Stick to software crc32 even if hardware is capable of that
Date: Fri, 11 Oct 2013 15:02:35 +0800 [thread overview]
Message-ID: <5257A28B.8000507@windriver.com> (raw)
In-Reply-To: <20131010131116.GA16147@hmsreliant.think-freely.org>
On 2013年10月10日 21:11, Neil Horman wrote:
> On Thu, Oct 10, 2013 at 01:51:36PM +0800, Fan Du wrote:
>> igb/ixgbe have hardware sctp checksum support, when this feature is enabled
>> and also IPsec is armed to protect sctp traffic, ugly things happened as
>> xfrm_output checks CHECKSUM_PARTIAL to do check sum operation(sum every thing
>> up and pack the 16bits result in the checksum field). The result is fail
>> establishment of sctp communication.
>>
> Shouldn't this be fixed in the xfrm code then? E.g. check the device features
> for SCTP checksum offloading and and skip the checksum during xfrm output if its
> available?
sigh... same as my first thought.
However why should xfrm_output check whether the skb is a SCTP one as well as whether
the associated dev is able to do hw SCTP crc32-c checksum in the first place, and then
call SCTP crc checksum value API to write the correct checksum *after* this skb has
leaven SCTP layer???
The checksum operation in xfrm_ouput fits TCP/UDP/IP layer checksum semantics, e.g.
calculate 16bits value by sum almost everything up. Make a SCTP specific exception
in this common path sound wired, as the fix can be done in SCTP codes easily with
minimum changes, so not any bit of consequence for non-SCTP traffic.
And If you/Vlad insist to do so as well as no objection from Steffen/David, I'm
happy to send this revised version as your suggested.
Anyway, I should have separated this patch for two which makes the issues more clear
for you and Vlad to review.
> Or am I missing something?
> Neil
>
>
--
浮沉随浪只记今朝笑
--fan
next prev parent reply other threads:[~2013-10-11 7:03 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-10 5:51 [PATCH net] {xfrm, sctp} Stick to software crc32 even if hardware is capable of that Fan Du
2013-10-10 13:11 ` Neil Horman
2013-10-11 7:02 ` Fan Du [this message]
2013-10-11 7:05 ` [PATCHv2 1/2 ] " Fan Du
2013-10-11 14:04 ` Vlad Yasevich
2013-10-11 17:12 ` Vlad Yasevich
2013-10-11 7:08 ` [PATCHv2 2/2] Don't compute checksum value for SCTP skb with, CHECKSUM_PARTIAL set Fan Du
2013-10-11 14:25 ` Vlad Yasevich
2013-10-12 9:45 ` Fan Du
2013-10-12 13:06 ` Vlad Yasevich
2013-10-14 7:16 ` Fan Du
2013-10-10 14:11 ` [PATCH net] {xfrm, sctp} Stick to software crc32 even if hardware is capable of that Vlad Yasevich
2013-10-11 7:02 ` Fan Du
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