[ovs-discuss] Problem with a desired flow getting deleted

[Todd Deshane]

On Fri, Feb 12, 2010 at 2:51 PM, Todd Deshane <deshantm at gmail.com> wrote:
> So I think the next problem that I would like to solve is getting the
> host network to work correctly. When I do the obvious of simply
> copying the flows for the VM and changing the mac address to that of
> eth0, the host is not able to work as I would have expected. It can
> dhcp, but that seems like all it can do. It can't lookup any over dns,
> or anything else. The strange thing is that its flows don't seem to be
> showing up anywhere (I check the switch logs), I only seem ARP traffic
> for the eth0 mac and nothing else.

I think I've found a specific case of normal traffic from the host
that is getting deleted.

First, a dump of the default flow table for dp0/externalbr:
ovs-ofctl dump-flows dp0
Feb 13 22:31:51|00001|ofctl|INFO|datapath dp0 is named externalbr
Feb 13 22:31:51|00002|ofctl|INFO|connecting to
unix:/usr/local/var/run/externalbr.mgmt
stats_reply (xid=0xf7b36636): flags=none type=1(flow)
  duration=95286s, table_id=1, priority=0, n_packets=281959,
n_bytes=28181037, actions=NORMAL

and to refresh you, for sake of convenience, the switch config is:

bridge.internalbr.port=internalbr
bridge.externalbr.port=externalbr
bridge.internalbr.mac=00:11:22:aa:cc:ee
bridge.externalbr.mac=00:11:22:bb:aa:dd
bridge.externalbr.port=eth0

So, with this in place, is there any reason why this flow is being deleted:

Feb 13 22:24:23|746001|dpif|DBG|dp0: delete flow in_port0000:vlan65535
mac00:11:22:bb:aa:dd->00:1c:0f:95:1d:42 type0800 proto17
ip128.153.144.73->128.153.N.N port51679->53, packets:0, bytes:0,
used:never

It seems to be DNS traffic from externalbr to a local DNS server (IP
masked with N.N.)

My suspicion is that the problem has to do with mac address and/or
some mis-coordination between eth0 and externalbr

eth0 has a mac of 00:23:54:87:21:3c, and similarly has a useful flow
being deleted. This looks like a DHCP response:

Feb 13 22:22:43|744867|dpif|DBG|dp0: delete flow in_port0001:vlan65535
mac00:1c:0f:95:1d:42->00:23:54:87:21:3c type0800 proto17
ip128.153.144.1->128.153.144.198 port67->68, packets:1, bytes:350,
used:5.864s

I also found other similar examples of flows being deleted.

This testing is all after a fresh reboot, and only loading the switch
with the config given above, then just simply trying to get the host's
networking to work. Note that for this particular test, I did not
delete or add any flows form the default setup of the switch. The only
way that I have found that I can get networking to work is to dpctl
del-if externalbr eth0, then restart networking on eth0.

Any ideas or things for me to try?

Thanks,
Todd

-- 
Todd Deshane
http://todddeshane.net
http://runningxen.com