On Wed, Feb 08, 2023 at 01:38:36PM +0000, Parav Pandit wrote: > > > From: Michael S. Tsirkin <m...@redhat.com> > > Sent: Wednesday, February 8, 2023 8:32 AM > > > > On Wed, Feb 08, 2023 at 05:18:32AM +0000, Parav Pandit wrote: > > > > From: Heng Qi <hen...@linux.alibaba.com> > > > > Sent: Tuesday, February 7, 2023 10:25 PM > > > > > > [..] > > > > >> > > > > >> Do you think we need both hash_types and hash_tunnel_types? > > > > > In struct virtio_net_config we need two fields. > > > > > a. supported_hash_types (already exists) b. > > > > > supported_hash_tunnel_type > > > > > -> bitmap indicating for which outer headers, inner hash > > > > > -> calculation is > > > > supported. > > > > > > > > Thanks for the suggestion, we seem to have reached an agreement. > > > > > > > > > > > > > > In struct virtio_net_hdr we need two fields. > > > > > a. hash_report (already exists) > > > > > b. hash_tunnel_type 8 bits -> absolute value indicating which > > > > > outer header > > > > exists when inner header hash calculated. > > > > > You already have it in your patch named as hash_report_tunnel. > > > > > May be better to name as hash_report_tunnel_type to make it > > > > > clearer that its > > > > type. > > > > > > > > Sure. > > > > > > > > Thanks for your reply. > > > > > > I had one last question. Why do we need to inform the > > hash_report_tunnel_type of the outer header in the virtio_net_hdr? > > > Is this for debug? Or is there a use case that will process this value? > > > > Well we have hash_report which is kind of similar (and also kind of > > pointless > > but I think it's there because WHQL wants it). > Hash_report is useful. It tells hash_value is in which namespace > (ipv4-tcp/ipv4 udp etc). > OS can use this value to find tcp connection in a given namespace. > > > Maybe we can steal some bits > > from there instead of a new field? > > > I do not have problem adding extra bits. I just don't find that just telling > that its vxlan or nvgre to the OS is useful. > If OS needs to know about outer header details, it needs to know the VNI > information than just telling vxlan.
This does make sense. > > > > I have a follow up question though: are we only hashing the inner header or > > both inner and outer header? Somewhat confused on this. > > > I understood as inner header. But worth to describe it. May be there. Need to > read v8 patch. Hmm. I just realized that there's a security problem with hashing just the inner header: it allow users inside the tunnel control queueing outside. By observing packet loss some information leaks between tunnels. Ideas for solving this they all involve hashing both inner and outer header: 1- report two sets of hashes. overkill? 2- hash both headers together 2- add salt. can come from driver or device itself More ideas? -- MST --------------------------------------------------------------------- To unsubscribe, e-mail: virtio-dev-unsubscr...@lists.oasis-open.org For additional commands, e-mail: virtio-dev-h...@lists.oasis-open.org
