netdev - Re[3]: [PATCH 2/3] ipvs: Fix faulty IPv6 extension header handling in IPVS

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Message-ID: <mdaatbj.7a4274ea6c8f14ea15788c8953acb422@obelix.schillstrom.com>
Date:	Mon, 27 Aug 2012 13:58:18 +0200 (CEST)
From:	"Hans Schillstrom" <hans@...illstrom.com>
To:	"Patrick McHardy" <kaber@...sh.net>
Cc:	"Jesper Dangaard Brouer" <brouer@...hat.com>,
	netdev@...r.kernel.org, lvs-devel@...r.kernel.org,
	"Julian Anastasov" <ja@....bg>,
	"Simon Horman" <horms@...ge.net.au>,
	"Wensong Zhang" <wensong@...ux-vs.org>,
	netfilter-devel@...r.kernel.org
Subject: Re[3]: [PATCH 2/3] ipvs: Fix faulty IPv6 extension header 
	handling in IPVS

>>>
>>> On Mon, 20 Aug 2012, Jesper Dangaard Brouer wrote:
>>>
>>>> Based on patch from: Hans Schillstrom
>>>>
>>>> IPv6 headers must be processed in order of appearance,
>>>> neither can it be assumed that Upper layer headers is first.
>>>> If anything else than L4 is the first header IPVS will throw it.
>>>>
>>>> IPVS will write SNAT & DNAT modifications at a fixed pos which
>>>> will corrupt the message. Proper header position must be found
>>>> before writing modifying packet.
>>>>
>>>> This patch contains a lot of API changes.  This is done, to avoid
>>>> the costly scan of finding the IPv6 headers, via ipv6_find_hdr().
>>>> Finding the IPv6 headers is done as early as possible, and passed
>>>> on as a pointer "struct ip_vs_iphdr *" to the affected functions.
>>>
>>> How about we change netfilter to set up the skb's transport header
>>> at an early time so we can avoid all (most of) these header scans
>>> in netfilter?
>>
>> I think that would be great, maybe it should be global i.e. not only a netfilter issue.
>
>I think in most other cases the headers are supposed to be processed 
>sequentially. One problem though - to be useful for netfilter/IPVS
>we'd also need to store the transport layer protocol somewhere.

I guess that's the problem, adding it to the skb will not be popular ....
Right now I don't have a good solution, maybe a more generic netfilter ptr in the skb ...



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