[dpdk-dev] [PATCH] vhost: broadcast RARP pkt by injecting it to receiving mbuf array

Qiu, Michael michael.qiu at intel.com
Thu Feb 25 08:55:49 CET 2016


On 2/24/2016 4:27 PM, Yuanhan Liu wrote:
> On Wed, Feb 24, 2016 at 08:15:36AM +0000, Qiu, Michael wrote:
>> On 2/22/2016 10:35 PM, Yuanhan Liu wrote:
>>> Broadcast RARP packet by injecting it to receiving mbuf array at
>>> rte_vhost_dequeue_burst().
>>>
>>> Commit 33226236a35e ("vhost: handle request to send RARP") iterates
>>> all host interfaces and then broadcast it by all of them.  It did
>>> notify the switches about the new location of the migrated VM, however,
>>> the mac learning table in the target host is wrong (at least in my
>>> test with OVS):
>>>
>>>     $ ovs-appctl fdb/show ovsbr0
>>>      port  VLAN  MAC                Age
>>>         1     0  b6:3c:72:71:cd:4d   10
>>>     LOCAL     0  b6:3c:72:71:cd:4e   10
>>>     LOCAL     0  52:54:00:12:34:68    9
>>>         1     0  56:f6:64:2c:bc:c0    1
>>>
>>> Where 52:54:00:12:34:68 is the mac of the VM. As you can see from the
>>> above, the port learned is "LOCAL", which is the "ovsbr0" port. That
>>> is reasonable, since we indeed send the pkt by the "ovsbr0" interface.
>>>
>>> The wrong mac table lead all the packets to the VM go to the "ovsbr0"
>>> in the end, which ends up with all packets being lost, until the guest
>>> send a ARP quest (or reply) to refresh the mac learning table.
>>>
>>> Jianfeng then came up with a solution I have thought of firstly but NAKed
>> Is it suitable to mention someone in the commit log?
> Why it's not? It's not a secret name or something like that after all :)
>
> On the other hand, it's way of thanking Jianfeng's contribution to this
> patch.

OK, I've never seen this fashion before, forgive me.

Thanks,
Michael
>
> 	--yliu
>



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