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From: Li Wei <lw@cn•fujitsu.com>
To: Steffen Klassert <steffen.klassert@secunet•com>
Cc: netdev <netdev@vger•kernel.org>
Subject: Re: Question with commit 299b0767(ipv6: Fix IPsec slowpath fragmentation problem)
Date: Wed, 15 Feb 2012 15:00:04 +0800	[thread overview]
Message-ID: <4F3B57F4.10106@cn.fujitsu.com> (raw)
In-Reply-To: <20120214110414.GA31660@secunet.com>

Steffen Klassert wrote:
> On Mon, Feb 13, 2012 at 04:10:39PM +0800, Li Wei wrote:
>> Hi, Steffen!
>>
>> I found some problem while doing networking tests with IPSec that
>> the first fragment doesn't use the max MTU to fill payload, but with
>> 20 bytes smaller. When I reverted your commit 299b0767(ipv6: Fix 
>> IPsec slowpath fragmentation problem), things goes well.
>>
>> Would you so kindly to point me out what the commit did, because I
>> think the original implementation had taken IPSec header and tailer
>> into account.
>>
> 
> Without this patch we used always the slow path in ip6_fragment()
> due to a miscalculation of the packet lenght in ip6_append_data().
> 
> This patch just makes use of the reduced IPsec mtu, and adapts
> the IPsec header handling to have enought headroom on the skb.
> 
> 

Hi Steffen,

Thank you for your reply!

I see in your patch that you use the "mtu" of &rt->dst (which taken IPSec
into account) instead of rt->dst.path, but the "exthdrlen" and "dst_exthdrlen"
things process IPSec again. Does some duplication there?

After reverted the patch and put some "printk" things in the slow_path of
ip6_fragment(), setup IPSec transport mode between two hosts, when sending
some echo request which exceeds the MTU, I don't see any "printk" in slow_path
outputed. Could you tell me how to reproduce the slow_path things?

Thanks,
Wei

next prev parent reply	other threads:[~2012-02-15  7:00 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-13  8:10 Question with commit 299b0767(ipv6: Fix IPsec slowpath fragmentation problem) Li Wei
2012-02-14 11:04 ` Steffen Klassert
2012-02-15  7:00   ` Li Wei [this message]
2012-02-15 10:40     ` Steffen Klassert
2012-05-14  3:21       ` [PATCH] ipv6: fix incorrect ipsec transport mode fragment Gao feng
2012-05-14 13:05         ` Steffen Klassert
2012-05-14 22:41           ` David Miller
2012-05-17  7:42             ` Gao feng
2012-05-17  8:48               ` David Miller
2012-05-15  3:44           ` Gao feng
2012-05-15 11:48             ` Steffen Klassert
2012-05-16  2:59               ` Gao feng
2012-05-26  9:00           ` Gao feng
2012-05-26 11:29             ` Gao feng
2012-05-26 11:30         ` [PATCH v2] ipv6: fix incorrect ipsec fragment Gao feng
2012-05-27  5:12           ` David Miller

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