[PATCH bpf-next 0/5] Add the the capability to load HW RX checsum in eBPF programs

[Lorenzo Bianconi <lorenzo@kernel.org>]

Introduce bpf_xdp_metadata_rx_checksum() kfunc in order to load the HW
RX cheksum 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 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 (5):
      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

 Documentation/netlink/specs/netdev.yaml            |   5 +
 drivers/net/ethernet/intel/ice/ice_txrx_lib.c      | 114 +++++++++++++--------
 drivers/net/veth.c                                 |  20 ++++
 include/net/xdp.h                                  |  14 +++
 include/uapi/linux/netdev.h                        |   3 +
 net/core/xdp.c                                     |  29 ++++++
 tools/include/uapi/linux/netdev.h                  |   3 +
 .../selftests/bpf/prog_tests/xdp_metadata.c        |   7 ++
 .../testing/selftests/bpf/progs/xdp_hw_metadata.c  |   7 ++
 tools/testing/selftests/bpf/progs/xdp_metadata.c   |   1 +
 tools/testing/selftests/bpf/xdp_hw_metadata.c      |  28 +++++
 tools/testing/selftests/bpf/xdp_metadata.h         |  13 +++
 12 files changed, 204 insertions(+), 40 deletions(-)
---
base-commit: db975debcb8c4cd367a78811bc1ba84c83f854bd
change-id: 20250925-bpf-xdp-meta-rxcksum-900685e2909d

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