[ovs-dev] [RFC v4] Add TCP encap_rcv hook (repost)

Jesse Gross jesse at nicira.com
Mon Apr 23 22:59:24 UTC 2012


On Mon, Apr 23, 2012 at 3:32 PM, Simon Horman <horms at verge.net.au> wrote:
> On Mon, Apr 23, 2012 at 02:38:07PM -0700, Jesse Gross wrote:
>> On Mon, Apr 23, 2012 at 2:08 PM, David Miller <davem at davemloft.net> wrote:
>> > From: Jesse Gross <jesse at nicira.com>
>> > Date: Mon, 23 Apr 2012 13:53:42 -0700
>> >
>> >> On Mon, Apr 23, 2012 at 1:13 PM, David Miller <davem at davemloft.net> wrote:
>> >>> From: Jesse Gross <jesse at nicira.com>
>> >>> Date: Mon, 23 Apr 2012 13:08:49 -0700
>> >>>
>> >>>> Assuming that the TCP stack generates large TSO frames on transmit
>> >>>> (which could be the local stack; something sent by a VM; or packets
>> >>>> received, coalesced by GRO and then encapsulated by STT) then you can
>> >>>> just prepend the STT header (possibly slightly adjusting things like
>> >>>> requested MSS, number of segments, etc. slightly).  After that it's
>> >>>> possible to just output the resulting frame through the IP stack like
>> >>>> all tunnels do today.
>> >>>
>> >>> Which seems to potentially suggest a stronger intergration of the STT
>> >>> tunnel transmit path into our IP stack rather than the approach Simon
>> >>> is taking
>> >>
>> >> Did you have something in mind?
>> >
>> > A normal bonafide tunnel netdevice driver like GRE instead of the
>> > openvswitch approach Simon is using.
>>
>> Ahh, yes, that I agree with.  Independent of this, there's work being
>> done to make it so that OVS can use the normal in-tree tunneling code
>> and not need its own.  Once that's done I expect that STT will follow
>> the same model.
>
> Hi Jesse,
>
> I am wondering how firm the plans to on allowing OVS to use in-tree tunnel
> code are. I'm happy to move my efforts over to an in-tree STT implementation
> but ultimately I would like to get STT running in conjunction with OVS.

I would say that it's a firm goal but the implementation probably
still has a ways to go.  Kyle Mestery (CC'ed) has volunteered to work
on this in support of adding VXLAN, which needs some additional
flexibility that this approach would also provide.  You might want to
talk to him to see if there are ways that you guys can work together
on it if you are interested.  Having better integration with upstream
tunneling is definitely a step that OVS needs to make and sooner would
be better than later.



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