Re: [PATCH net-next 0/5] flower: match on the number of vlan tags

[Jamal Hadi Salim <jhs@mojatatu.com>]

On 2022-04-11 09:30, Boris Sukholitko wrote:
> Hi,
> 
> Our customers in the fiber telecom world have network configurations
> where they would like to control their traffic according to the number
> of tags appearing in the packet.
> 
> For example, TR247 GPON conformance test suite specification mostly
> talks about untagged, single, double tagged packets and gives lax
> guidelines on the vlan protocol vs. number of vlan tags.
> 
> This is different from the common IT networks where 802.1Q and 802.1ad
> protocols are usually describe single and double tagged packet. GPON
> configurations that we work with have arbitrary mix the above protocols
> and number of vlan tags in the packet.
> 
> The following patch series implement number of vlans flower filter. They
> add num_of_vlans flower filter as an alternative to vlan ethtype protocol
> matching. The end result is that the following command becomes possible:
> 
> tc filter add dev eth1 ingress flower \
>    num_of_vlans 1 vlan_prio 5 action drop
> 

The idea looks sane. I guess flow dissector is now not just involving
headers but metadata as well. I can see this applied to MPLS for 
example, etc.
Can you please provide more elaborate example of more than 1 vlan?

Where would the line be drawn:
Is it max of two vlans?
Is there potential of <=X, meaning matching of upto X Vlans?

cheers,
jamal