[dpdk-dev] [PATCH] mbuf: fix to update documentation of QinQ stripped bit interpretation

Stephen Hemminger stephen at networkplumber.org
Wed Feb 26 01:55:41 CET 2020


On Fri, 7 Feb 2020 15:29:59 +0100
Olivier Matz <olivier.matz at 6wind.com> wrote:

> The meaning of each flag should be as simple as possible, I think we can
> summarize them like this:
> 
> - PKT_RX_VLAN: the vlan is saved in vlan tci.
> - PKT_RX_VLAN_STRIPPED: the vlan hdr is removed from packet data.
> - PKT_RX_QINQ: the outer vlan is saved in vlan tci.
> - PKT_RX_QINQ_STRIPPED: the inner vlan is stripped from packet data.
> - When PKT_RX_QINQ is set, PKT_RX_VLAN* refer to the inner vlan
>   of initial packet, else it refers to the first vlan of the packet.
> 
> There is a link between vlan flag and vlan_tci field, and qinq flag and
> vlan_tci_outer field.
> 
> I'm still not sure to understand what you expect. Can you give an
> example with flags (which are set), and the expected content of m->vlan_tci
> and m->vlan_tci_outer?
> 
> By the way, the case 5/ is not very well described too, maybe we should
> add something about it.
> 
> Thanks,
> Olivier

The patch does help clarify the meaning, and Oliver's summary clarifies
even more. It might be possible for hardware to offload inner vlan but
not outer vlan, though seriously doubt anyone but some conformance test
would do that.
 


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