[ovs-dev] [PATCH v4 0/4] Support native dhcp in ovn controller

Russell Bryant russell at ovn.org
Mon Mar 28 17:39:58 UTC 2016


On Mon, Mar 28, 2016 at 10:16 AM, Numan Siddique <nusiddiq at redhat.com>
wrote:

>
>
> On Mon, Mar 28, 2016 at 6:58 PM, Russell Bryant <russell at ovn.org> wrote:
>
>>
>>
>> On Thu, Mar 17, 2016 at 2:34 AM, Numan Siddique <nusiddiq at redhat.com>
>> wrote:
>>
>>> On 03/16/2016 10:44 PM, Russell Bryant wrote:
>>> > It could also be this:
>>> >
>>> > dhcp_offer(offer_ip=10.0.0.3, netmask=255.255.255.0, mtu=1300,
>>> > dns={8.8.8.8, 7.7.7.7});
>>>
>>> Thanks. This seems better to me.
>>>
>>
>> Where do you get the source MAC and IP for the DHCP responses?
>>
>>
> ​For the initial testing I had harcoded source MAC to some value and left
> the source ip unchanged i.e it 0.0.0.0
>
>
> https://github.com/numansiddique/ovs/blob/dhcp_pause_rfc_working/ovn/northd/ovn-northd.c#L1132
>
> I think it should be ok if the ovn-controller sets the source ip to
> 0.0.0.0, but not sure what should be set for source mac.
>

I'm not sure if a src of 0.0.0.0 is a good idea.  Wouldn't that typically
be the IP address of the DHCP server?  I'd be worried about some clients
treating it as invalid.

I think it should be specified by logical flows.  Something like:

    dhcp_offer(offer_ip=10.0.0.3, netmask=255.255.255.0,
mtu=1300, dns={8.8.8.8, 7.7.7.7}); eth.dst = eth.src; eth.src =
<SOMETHING>; ip.src = <SOMETHING>; outport = inport; inport = ""; output;

As for what addresses to use ... I don't know.  I think it should be
specified via OVN_Northbound, somehow.  It's easy enough for Neutron to
generate an IP and MAC to use.  It already creates DHCP ports for this
purpose.  Maybe it could just be additional logical port options, like
you're doing for the rest of the DHCP parameters?

-- 
Russell Bryant



More information about the dev mailing list