On Tue, Sep 20, 2016 at 10:09 AM, Jiri Benc <jb...@redhat.com> wrote: > On Tue, 20 Sep 2016 18:43:33 +0200, Jiri Benc wrote: >> On Tue, 20 Sep 2016 12:31:08 -0400, Sowmini Varadhan wrote: >> > The vxlan header is after the ethernet header (14 bytes), >> > IP header (20 bytes, assuming no options) and udp header (8 bytes). >> >> If the VXLAN header is not aligned to 4 bytes, then IP header is not >> aligned to 4 bytes, too, and you have greater problems than just VXLAN. > > ...which is indeed the case. Sorry, I guess I'm too much focused on > VXLAN-GPE nowadays and I missed that we're building this before the > inner Ethernet header. > > But the point stands, we have much greater problems here than VXLAN. > And I don't think that wrapping all IP address accesses into > get/put_unaligned all around the stack is the solution. > RIght, this is problem with the encapsulations themselves. IP protocols are supposed to be four-byte aligned and Ethernet encapsulation is obviously breaking that. We can't address this in existing standards like GRE-TEB, but for new encapsulations we should make sure this avoided. I've posted on nvo3 list about this issue.
Tom > Jiri
