Messages in this thread | | | Subject | Re: [RFC PATCH] lro: ip fragment checking | From | Ben Hutchings <> | Date | Mon, 24 Nov 2008 16:51:08 +0000 |
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On Mon, 2008-11-24 at 16:56 +0100, Jan-Bernd Themann wrote: > Currently there is no checking in the LRO receive path whether > TCP packets are ip fragmented. We should not consider > those packets for aggregation. > I'm not sure if this checking is actually required. Does anyone > know if it is possible to get fragmented TCP packets without > the tcp stack changing the MSS size? > This patch introduces explicit checking. Any objections?
LRO depends on the hardware performing TCP checksum offload, and the TCP checksum cannot be verified for IP fragments in isolation. So I think drivers should not be passing fragments into inet_lro or should reject them in its get_frag_header() or get_skb_header() method. Certainly sfc doesn't pass fragments into inet_lro because they have not been checksummed.
Ben.
-- Ben Hutchings, Senior Software Engineer, Solarflare Communications Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked.
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