[Intel-wired-lan] hardware filter for matching GTP-U TEID

[Subbaraya Sundeep Bhatta]

Hi Marcin Szycik,

Below commit demonstrates that we need to create a GTP tunnel netdev and
create a tc filter on top of it. I am unable to understand how the tc filter on top of
tunnel netdev $GTP0 propagates to the interface $PF0 for hardware offload?


commit 97aeb877de7f14f819fc2cf8388d7a2d8090489d
Merge: 4d17d43 9a225f8
Author: David S. Miller <davem at davemloft.net>
Date:   Sat Mar 12 11:54:29 2022 +0000

    Merge branch '100GbE' of git://git.kernel.org/pub/scm/linux/kernel/git/tnguy/next-queue

    Tony Nguyen says:

    ====================
    ice: GTP support in switchdev

    Marcin Szycik says:

    Add support for adding GTP-C and GTP-U filters in switchdev mode.

    To create a filter for GTP, create a GTP-type netdev with ip tool, enable
    hardware offload, add qdisc and add a filter in tc:

    ip link add $GTP0 type gtp role <sgsn/ggsn> hsize <hsize>
    ethtool -K $PF0 hw-tc-offload on
    tc qdisc add dev $GTP0 ingress
    tc filter add dev $GTP0 ingress prio 1 flower enc_key_id 1337 \
    action mirred egress redirect dev $VF1_PR


I have to redirect GTP-U packets with a TEID to a VF which may be in guest using hardware tc filter on PF.
>From my understanding current TC and ethtool cannot specify match filters beyond L4 header fields.
Can I add new command something like gtp-teid to tc filter?
Please help me understand this.

Thanks,
Sundeep