This patchset adds a software GRO codepath for IPsec ESP. The ESP gro_receive callback functions decapsulate the ESP packets at the GRO layer and reinject them back with gro_cells_receive(). This saves a complete round through the stack for IPsec ESP packets.
We also need this for ESP HW offload, because HW decrypt but does not decapsulate the packet. We need to decapsulate before the inbound policy check, otherwise this check will fail. Patches 2 an 3 prepare the generic code for packet consuming gro callbacks.
