netdev - [RFC PATCH net-next 0/2] net: tc: dsa: Implement offload of matchall for bridged DSA ports

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Message-Id: <20220330113116.3166219-1-mattias.forsblad@gmail.com>
Date:   Wed, 30 Mar 2022 13:31:14 +0200
From:   Mattias Forsblad <mattias.forsblad@...il.com>
To:     netdev@...r.kernel.org
Cc:     Andrew Lunn <andrew@...n.ch>,
        Vivien Didelot <vivien.didelot@...il.com>,
        Florian Fainelli <f.fainelli@...il.com>,
        Vladimir Oltean <olteanv@...il.com>,
        "David S . Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Tobias Waldekranz <tobias@...dekranz.com>,
        Mattias Forsblad <mattias.forsblad@...il.com>
Subject: [RFC PATCH net-next 0/2] net: tc: dsa: Implement offload of matchall for bridged DSA ports

Greetings,

This series implements offloading of tc matchall filter to HW
for bridged DSA ports.

Background
When using a non-VLAN filtering bridge we want to be able to drop
traffic directed to the CPU port so that the CPU doesn't get unnecessary loaded.
This is specially important when we have disabled learning on user ports.

A sample configuration could be something like this:

       br0
      /   \
   swp0   swp1

ip link add dev br0 type bridge stp_state 0 vlan_filtering 0
ip link set swp0 master br0
ip link set swp1 master br0
ip link set swp0 type bridge_slave learning off
ip link set swp1 type bridge_slave learning off
ip link set swp0 up
ip link set swp1 up
ip link set br0 up

After discussions here: https://lore.kernel.org/netdev/YjMo9xyoycXgSWXS@shredder/
it was advised to use tc to set an ingress filter that could then
be offloaded to HW, like so:

tc qdisc add dev br0 clsact
tc filter add dev br0 ingress pref 1 proto all matchall action drop

Limitations
If there is tc rules on a bridge and all the ports leave the bridge
and then joins the bridge again, the indirect framwork doesn't seem
to reoffload them at join. The tc rules need to be torn down and
re-added.

The first part of this serie uses the flow indirect framework to
setup monitoring of tc qdisc and filters added to a bridge.
The second part offloads the matchall filter to HW for Marvell
switches.

Mattias Forsblad (2):
  net: tc: dsa: Add the matchall filter with drop action for bridged DSA ports.
  net: dsa: Implement tc offloading for drop target.

 drivers/net/dsa/mv88e6xxx/chip.c |  23 +++-
 include/net/dsa.h                |  13 ++
 net/dsa/dsa2.c                   |   5 +
 net/dsa/dsa_priv.h               |   3 +
 net/dsa/port.c                   |   1 +
 net/dsa/slave.c                  | 217 ++++++++++++++++++++++++++++++-
 6 files changed, 258 insertions(+), 4 deletions(-)

-- 
2.25.1