Re: [PATCH 2/2] IB/ipoib: fix GRO merge failure for IPoIB originated TCP streams

Le lundi 30 janvier 2012 à 19:18 +1100, Herbert Xu a écrit :

On Mon, Jan 30, 2012 at 09:04:32AM +0100, Eric Dumazet wrote:

quoted

Hmm, do we really need to compare ether header, thats the question.

I think we do.  As otherwise macvlan would break.

Thats the theory yes, but practically ?

Really, GRO can merge two TCP frames given they match everything needed,
exactly as our TCP stack would do in the end.

What could be a normal workload where this mismatch of two different tcp
flows could happen with macvlan or any kind of devices ?

If this is an attack, TCP will merge the frames anyway on the same
socket.

Or should we add checks in TCP stack, in case GRO is off ?



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On Mon, Jan 30, 2012 at 09:53:03AM +0100, Eric Dumazet wrote:

If this is an attack, TCP will merge the frames anyway on the same
socket.

Not if we have a MAC-level filter in place or VLANs.

Cheers,
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