Re: [PATCH 08/14] net: vlan: remove invalid VLAN protocol warning

[Felix Fietkau <nbd@nbd.name>]

On 08.11.22 11:08, Vladimir Oltean wrote:
> On Tue, Nov 08, 2022 at 10:46:54AM +0100, Felix Fietkau wrote:
>> I think it depends on the hardware. If you can rely on the hardware always
>> reporting the port out-of-band, a generic "oob" tagger would be fine.
>> In my case, it depends on whether a second non-DSA ethernet MAC is active on
>> the same device, so I do need to continue using the "mtk" tag driver.
> 
> It's not only about the time dimension (always OOB, vs sometimes OOB),
> but also about what is conveyed through the OOB tag. I can see 2 vendors
> agreeing today on a common "oob" tagger only to diverge in the future
> when they'll need to convey more information than just port id. What do
> you do with the tagging protocol string names then. Gotta make them
> unique from the get go, can't export "oob" to user space IMO.
> 
>> The flow dissector part is already solved: I simply used the existing
>> .flow_dissect() tag op.
> 
> Yes, well this seems like a generic enough case (DSA offload tag present
> => don't shift network header because it's where it should be) to treat
> it in the generic flow dissector and not have to invoke any tagger-specific
> fixup method.
In that case I think we shouldn't use METADATA_HW_PORT_MUX, since it is 
already used for other purposes. I will add a new metadata type 
METADATA_DSA instead.

- Felix