On (09/28/16 11:08), Alexander Duyck wrote: > > - then udp_gro_receive -> vxlan_gro_receive pulls up vxlan header > > into linear part, and then.. > > This is the point where we need to stop, drop the existing headers, > call skb_reserve(NET_IP_ALIGN), and then pick back up where we left > off. We just have to make sure the skbuff isn't shared. : > In general the interface behind the tunnel shouldn't need to know > about any of the data in front of the tunnel, so you should be able to > drop the original header offsets and reset things if you want so you > could overwrite the old headers.
Except that some of these encapsulations may be doing things like [inner-mac, outer-ip] fdb learning, so we may not be able to lose the outer headers at this early point in all cases. > If I am not mistaken I think the multi-buffer approach is the approach > taken by other OSes, although for us it is more difficult since we yes, I think that's approximately what gets done with mblk/mbufs (with pullups as needed). But as you point out, this type of ->frag_list chaining is a non-trivial change. > I'm sure we are all going to be talking about this in great detail > next week at netdev/netconf.. :-) Agree. --Sowmini
