On Apr 26, 2012, at 11:13 AM, Jesse Gross wrote: > On Thu, Apr 26, 2012 at 12:13 AM, Simon Horman <ho...@verge.net.au> wrote: >> On Wed, Apr 25, 2012 at 10:17:25AM -0700, Jesse Gross wrote: >>> On Wed, Apr 25, 2012 at 1:39 AM, Simon Horman <ho...@verge.net.au> wrote: >>>> >>>> Hi Kyle, >>>> >>>> the component that is of most interest to me is enabling OVS to use in-tree >>>> tunnelling code - as it seems that makes most sense for an implementation >>>> of STT. I have taken a brief look over your vxlan work and it isn't clear >>>> to me if it is moving towards being an in-tree implementation. Moreover, >>>> I'm a rather unclear on what changes need to be made to OVS in order for >>>> in-tree tunneling to be used. >>>> >>>> My recollection is that OVS did make use of in-tree tunnelling code >>>> but this was removed in favour of the current implementation for various >>>> reasons (performance being one IIRC). I gather that revisiting in-tree >>>> tunnelling won't revisit the previous set of problems. But I'm unclear how. >>>> >>>> Jesse, is it possible for you to describe that in a little detail >>>> or point me to some information? >>> >>> This was what I had originally written a while back, although it's >>> more about OVS internally and less about how to connect to the in-tree >>> code: >>> http://openvswitch.org/pipermail/dev/2012-February/014779.html >>> >>> In order to flexibly implement support for current and future tunnel >>> protocols OVS needs to be able to get/set information about the outer >>> tunnel header when processing the inner packet. At the very least >>> this is src/dst IP addresses and the key/ID/VNI/etc. In the upstream >>> tunnel implementations those are implicitly encoded in the device that >>> sends or receives the packet. However, this has a two problems: >>> number of devices and ability to handle unknown values. We addressed >>> part of this problem by allowing the tunnel ID to be set and matched >>> through the OVS flow table and an action. In order to do this with >>> the in-tree tunneling code, we obviously need a way of passing this >>> information around since it would currently get lost as we pass >>> through the Linux device layer. >>> >>> The plan to deal with that is to add a function to the in-tree >>> tunneling code that allows a skb to be encapsulated with specific >>> parameters and conversely a hook to receive decapsulated packets along >>> with header info. This would make all of the kernel tunneling code >>> common, while still giving OVS userspace the ability to implement >>> essentially any type of tunneling policy. In many ways, this is very >>> similar to how vlans look in OVS today. >>> >>> While it would be possible to implement the hook to use the in-tree >>> tunnel code today without a lot of changes, we already know that we >>> want to move away from port-based model in the OVS kernel module >>> towards the flow model. As we push this upstream the userspace/kernel >>> API should be the correct one, so that's why these two things are tied >>> together. >> >> >> Thanks, that explanation along with Kyle's response helps a lot. >> >> It seems to me that something I could help out with is the implementation >> of the set_tunnel action which extents and replaces the tun_id action. >> It seems that is a requirement for the scheme you describe above. >> >> http://openvswitch.org/pipermail/dev/2012-April/016239.html > > I agree that's probably the best place to start unless Kyle has some > specific plans otherwise.
Simon and I chatted off-list, and this is indeed where we plan to start. _______________________________________________ dev mailing list dev@openvswitch.org http://openvswitch.org/mailman/listinfo/dev
