[ovs-dev] [PATCH] netdev-afxdp: Add pcap dump support.

Ilya Maximets i.maximets at ovn.org
Mon Dec 16 13:57:14 UTC 2019


On 16.12.2019 14:43, William Tu wrote:
> On Mon, Dec 16, 2019 at 1:41 AM Ilya Maximets <i.maximets at ovn.org> wrote:
>>
>> On 13.12.2019 21:59, William Tu wrote:
>>> Debugging netdev-afxdp is hard because tcpdump does not work
>>> at all, even for generic mode.  ovs-tcpdump which uses port
>>> mirroring also does not work for netdev-afxdp.
>>
>> Hmm.  Why ovs-tcpdump doesn't work for you?  It should not depend
>> on port type.  If it doesn't work we need to investigate this
>> case and fix it because it's a very important tool.
> 
> Because ovs-tcpdump still uses 'tcpdump' tool to capture packets,
> (dump-cmd=tcpdump) and forward to mirror port.  Since tcpdump
> sees no packet at all when type=afxdp, there is no packets to mirror.

ovs-tcpdump creates simple tap interface and mirrors all the traffic
to it.  tcpdump command is started on that tap interface (no xdp here).
There is no difference from which port types you're mirroring the traffic.
It works for DPDK based ports and should work for afxdp.


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