[ovs-dev] [RFC 0/2] ovn: add distributed NAT capability

Guru Shetty guru.ovn at gmail.com
Mon Oct 3 22:31:04 UTC 2016

> On Oct 3, 2016, at 3:17 PM, Mickey Spiegel <mickeys.dev at gmail.com> wrote:
> (+ ovs dev mailing list)
>> On Mon, Oct 3, 2016 at 1:40 PM, Guru Shetty <guru at ovn.org> wrote:
>>> On 17 August 2016 at 14:11, Mickey Spiegel <mickeys.dev at gmail.com> wrote:
>>> Currently OVN supports NAT functionality by connecting each distributed
>>> logical router to a centralized "l3gateway" router that resides on a
>>> single chassis.  NAT is only carried out in the "l3gateway" router.
>>> This patch set introduces NAT capability in the distributed logical
>>> router itself, avoiding the need to pass through a transit logical
>>> switch and a second logical router, and in many cases avoiding the need
>>> to pass through a centralized chassis.
>>> NAT functionality is associated with the logical router gateway port.
>>> In order to support one-to-many SNAT (aka IP masquerading), where
>>> multiple private IP addresses spread across multiple chassis are mapped
>>> to a single public IP address, it will be necessary to handle some of
>>> the logical router processing on a specific chassis in a centralized
>>> manner.  Some NAT flows are handled in a distributed manner on all
>>> chassis (following the local "patch" port as is normally done for
>>> distributed logical routers), while other NAT flows are handled on a
>>> centralized "redirect-chassis".
>>> This patch set is being sent out early to solicit feedback on the
>>> approach.  There are two required patches that have not yet been
>>> started:
>>> 1. Add match conditions that restrict a logical flow to a specified
>>>    chassis, and that restrict a logical flow to the chassis where a
>>>    specific logical port is resident.  These match conditions should be
>>>    evaluated in controller/lflow.c, preventing the flow from being sent
>>>    down to ofctl if the match conditions are not met.
>>> 2. Add egress loopback capability, along with associated
>>>    flags.egress_loopback.  When flags.egress_loopback is set, at the
>>>    end of the egress pipeline, instead of the packet being sent out the
>>>    outport, the packet is forced back to the beginning of the ingress
>>>    pipeline with inport = outport.  All other registers are cleared, as
>>>    if the packet just arrived on that inport.
>>>    This capability is needed in order to implement some of the
>>>    east/west NAT flows.
>>>    Note: The existing flags.loopback allows a packet to go from the end
>>>    of the ingress pipeline to the beginning of the egress pipeline with
>>>    outport = inport, which is different.
>>> Mickey Spiegel (2):
>>>   ovn: Introduce "chassisredirect" port binding
>>>   ovn: distributed NAT flows
>> I was mainly waiting for 2.6 release to get to anything that is not 2.6 related. There has been quite a bit of changes with respect to incremental processing, to make a good review on this. (I am also going on a vacation for a couple of weeks starting next.). If this is still of interest, would you mind re-spinning it?
> I have a rebase that I did a couple of weeks ago, but I am also close on the is_chassis_resident patch for this patch set (#1 above), which I hope will be enough to get north/south DNAT working. I am hoping to finish up that patch and send out v2 of this patch set in a couple of days. I also need to revisit my first take on gateway LB functionality as part of the rebase, whether to add a patch swapping the order of the NAT and LB flows (since some of the NAT code would be shared, applying to distributed NAT as well as gateway NAT), or instead add more LB flows to make it work on the chassis redirect port in the distributed router case.

If you are planning to send non-RFC patches, please add unit tests that show the workflow. It makes it easier to understand.

> Mickey
>>>  ovn/controller/binding.c            | 151 +++++++++++-
>>>  ovn/controller/ovn-controller.8.xml |  15 ++
>>>  ovn/controller/ovn-controller.c     |   8 +-
>>>  ovn/controller/physical.c           |  73 +++++-
>>>  ovn/controller/physical.h           |   2 +
>>>  ovn/northd/ovn-northd.8.xml         | 292 ++++++++++++++++++++++-
>>>  ovn/northd/ovn-northd.c             | 461 +++++++++++++++++++++++++++++++-----
>>>  ovn/ovn-nb.ovsschema                |  13 +-
>>>  ovn/ovn-nb.xml                      |  66 +++++-
>>>  ovn/ovn-sb.xml                      |  35 +++
>>>  10 files changed, 1028 insertions(+), 88 deletions(-)
>>> --
>>> 1.9.1
>>> _______________________________________________
>>> dev mailing list
>>> dev at openvswitch.org
>>> http://openvswitch.org/mailman/listinfo/dev

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