[Intel-wired-lan] [PATCH bpf-next v5 0/8] Add the the capability to load HW RX checksum in eBPF programs

[Lorenzo Bianconi]

Introduce bpf_xdp_metadata_rx_checksum() kfunc in order to load the HW
RX checksum results in the eBPF program binded to the NIC.
Implement xmo_rx_checksum callback for veth and ice drivers.

If the hardware detects a wrong/failed checksum, it will report
CHECKSUM_NONE in the packet metadata. Moreover, CHECKSUM_NONE will be
returned even if the NIC can't parse the packet (e.g. if it does not
support a specific protocol). A possible use case for
bpf_xdp_metadata_rx_checksum() would be to implement a XDP DDoS
application [1] combining the info from bpf_xdp_metadata_rx_checksum()
and bpf_xdp_metadata_rx_hash() kfuncs in order to filter packets with a
wrong/failed checksum.

[1] https://blog.cloudflare.com/unimog-cloudflares-edge-load-balancer/

---
Changes in v5:
- Add new kfunc to Documentation/networking/xdp-rx-metadata.rst
  documentation
- Introduce bpf_skb_rx_checksum kfunc and related selftest.
- Introduce selftest to check the driver invalidates the rx checksum if
  running in XDP mode.

Changes in v4:
- Report cusm and csum_level separately and convert ip_summed to a
  bitmask in bpf_xdp_metadata_rx_hash()
- Fix endianness issue in bpf selftests
- Add a comment about the driver expected behaviour if the the NIC reports
  CHECKSUM_UNNECESSARY or CHECKSUM_COMPLETE and the eBPF program modifes
  the packet
- Introduce bpf_get_skb_cksum kfunc and related selftest to load the
  checksum result to the SCHED_CLS eBPF program attached to the qdisc.
- Link to v3: https://lore.kernel.org/r/20260217-bpf-xdp-meta-rxcksum-v3-0-30024c50ba71@kernel.org

Changes in v3:
- Remoe leftover assignment from v2 in veth_xdp_rx_checksum()
- Fix typos
- Fix commit logs
- Link to v2: https://lore.kernel.org/r/20260213-bpf-xdp-meta-rxcksum-v2-0-a82c4802afbe@kernel.org

Changes in v2:
- Remove XDP_CHECKSUM_PARTIAL definition
- Improve veth_xdp_rx_checksum() callback
- Fix uninitialized case for cksum_meta in ice_get_rx_csum()
- Fix sparse warnings in ice driver
- Fix typos
- Link to v1: https://lore.kernel.org/r/20260210-bpf-xdp-meta-rxcksum-v1-0-e5d55caa0541@kernel.org

Changes in v1:
- Rebase on top of bpf-next
- Test ice driver using xdp_hw_metadata tool available in the bpf
  kernel selftest
- Improve cover letter with an use-case for
  bpf_xdp_metadata_rx_checksum()
- Link to RFC v2: https://lore.kernel.org/r/20250925-bpf-xdp-meta-rxcksum-v2-0-6b3fe987ce91@kernel.org

Changes in RFC v2:
- Squash patch 1/6 and 2/6
- Introduce enum xdp_checksum definitions
- Rework ice support to reuse ice_rx_csum codebase

---
Lorenzo Bianconi (8):
      netlink: specs: add XDP RX checksum capability to XDP metadata specs
      net: veth: add xmo_rx_checksum callback to veth driver
      net: ice: add xmo_rx_checksum callback
      selftests/bpf: add selftest support for bpf_xdp_metadata_rx_checksum
      selftests/bpf: add bpf_xdp_metadata_rx_checksum support to xdp_hw_metadat prog
      net: add bpf_skb_rx_checksum kfunc to read skb checksum metadata
      selftests/bpf: Add test for bpf_skb_rx_checksum kfunc
      selftests: net: add test for XDP_PASS skb checksum invalidation

 Documentation/netlink/specs/netdev.yaml            |   5 +
 Documentation/networking/xdp-rx-metadata.rst       |   8 ++
 drivers/net/ethernet/intel/ice/ice_txrx_lib.c      | 123 ++++++++++++++-------
 drivers/net/veth.c                                 |  32 ++++++
 include/net/xdp.h                                  |  13 +++
 include/uapi/linux/netdev.h                        |   3 +
 net/core/filter.c                                  |  31 ++++++
 net/core/xdp.c                                     |  32 ++++++
 tools/include/uapi/linux/netdev.h                  |   3 +
 tools/testing/selftests/bpf/bpf_kfuncs.h           |   8 ++
 .../selftests/bpf/prog_tests/skb_rx_checksum.c     |  50 +++++++++
 .../selftests/bpf/prog_tests/xdp_metadata.c        |   9 ++
 .../testing/selftests/bpf/progs/skb_rx_checksum.c  |  33 ++++++
 .../testing/selftests/bpf/progs/xdp_hw_metadata.c  |   7 ++
 tools/testing/selftests/bpf/progs/xdp_metadata.c   |   2 +
 tools/testing/selftests/bpf/skb_rx_checksum.h      |   8 ++
 tools/testing/selftests/bpf/xdp_hw_metadata.c      |  31 ++++++
 tools/testing/selftests/bpf/xdp_metadata.h         |  13 +++
 .../selftests/drivers/net/hw/xdp_metadata.py       |  55 ++++++++-
 .../selftests/net/lib/skb_metadata_csum.bpf.c      |  73 ++++++++++++
 20 files changed, 496 insertions(+), 43 deletions(-)
---
base-commit: f6f3b36c15ed44de1fbb44e645e4fae8c4a4453e
change-id: 20250925-bpf-xdp-meta-rxcksum-900685e2909d

Best regards,
-- 
Lorenzo Bianconi <lorenzo at kernel.org>