From: Alexander Duyck <adu...@mirantis.com> Date: Fri, 18 Mar 2016 16:24:38 -0700
> This patch series addresses two things. > > First it enables what I am calling RFC6864 compliant GRO. Basically what > I am doing is allowing one of two patterns for incoming frames. Either the > IP ID will increment, or if the DF bit is set it can either increment or > stay the same value. This allows us to perform GRO if the IP ID is forced > to stay at a static value as may occur if we are replicating an IP header > instead of actually having it offloaded. > > The last 3 patches introduce what I am calling GSO partial. The best way > to describe it is that it is a GSO offload in which the portion pointed to > by csum_start must be handled by the hardware, and the region before that > can be optionally handled. So for example with i40e the only pieces it was > missing from the full offload was the checksum so this is computed in > software and the hardware will update inner and outer IP headers. In the > example for ixgbe the hardware will only update the outer IP header. The > outer UDP or GRE header and inner IP header are unmodified. Conceptually I am completely fine with these changes. > The one concern here is that if the outer IP header does not have > the DF bit set and does not update the IP ID field we run the risk > of causing all sorts of problems if the packet is fragmented in > flight. I think we absolutely cannot let such a packet be output from our stack.
