On Mon, 2023-09-11 at 20:27 -0300, Victor Nogueira wrote:

__context__
The "tc block" is a collection of netdevs/ports which allow qdiscs to share
match-action block instances (as opposed to the traditional tc filter per
netdev/port)[1].

Example setup:
$ tc qdisc add dev ens7 ingress block 22
$ tc qdisc add dev ens8 ingress block 22

Once the block is created we can add a filter using the block index:
$ tc filter add block 22 protocol ip pref 25 \
  flower dst_ip 192.168.0.0/16 action drop

A packet with dst IP matching 192.168.0.0/16 arriving on the ingress of
either ens7 or ens8 is dropped.

__this patchset__
Up to this point in the implementation, the block is unaware of its ports.
This patch fixes that and makes the tc block ports available to the
datapath.

For the datapath we provide a use case of the tc block in an action
we call "blockcast" in patch 3. This action can be used in an example as
such:

$ tc qdisc add dev ens7 ingress block 22
$ tc qdisc add dev ens8 ingress block 22
$ tc qdisc add dev ens9 ingress block 22
$ tc filter add block 22 protocol ip pref 25 \
  flower dst_ip 192.168.0.0/16 action blockcast

When a packet(matching dst IP 192.168.0.0/16) arrives on the ingress of any
of ens7, ens8 or ens9 it will be copied to all ports other than itself.
For example, if it arrives on ens8 then a copy of the packet will be
"blockcasted";-> to both ens7 and ens9 (unmodified), but not to ens7.

Very minor typo above, "to ens7" should be "to ens8", I guess.

Not worthy reposting for this anyway.

Cheers,

Paolo