[PATCH bpf-next v3 0/6] XDP metadata support for tun driver

[Marcus Wichelmann]

Hi,

thank you for your reviw. As promised, here is V3 of this patch series.

I noticed that the updated selftests were flaky sometimes due to the kernel
networking stack sending IPv6 multicast listener reports on the created
test interfaces.
This can be seen here:
https://github.com/kernel-patches/bpf/actions/runs/13449071153/job/37580497963

Setting the NOARP flag on the interfaces should fix this race condition.

Successful pipeline:
https://github.com/kernel-patches/bpf/actions/runs/13500667544

Signed-off-by: Marcus Wichelmann <marcus.wichelmann@xxxxxxxxxxxxxxxx>
Acked-by: Jason Wang <jasowang@xxxxxxxxxx>
Reviewed-by: Willem de Bruijn <willemb@xxxxxxxxxx>

---

v3:
- change the condition to handle xdp_buffs without metadata support, as
  suggested by Willem de Bruijn <willemb@xxxxxxxxxx>
- add clarifying comment why that condition is needed
- set NOARP flag in selftests to ensure that the kernel does not send
  packets on the test interfaces that may interfere with the tests

v2: https://lore.kernel.org/bpf/20250217172308.3291739-1-marcus.wichelmann@xxxxxxxxxxxxxxxx/
- submit against bpf-next subtree
- split commits and improved commit messages
- remove redundant metasize check and add clarifying comment instead
- use max() instead of ternary operator
- add selftest for metadata support in the tun driver

v1: https://lore.kernel.org/all/20250130171614.1657224-1-marcus.wichelmann@xxxxxxxxxxxxxxxx/

Marcus Wichelmann (6):
  net: tun: enable XDP metadata support
  net: tun: enable transfer of XDP metadata to skb
  selftests/bpf: move open_tuntap to network helpers
  selftests/bpf: refactor xdp_context_functional test and bpf program
  selftests/bpf: add test for XDP metadata support in tun driver
  selftests/bpf: fix file descriptor assertion in open_tuntap helper

 drivers/net/tun.c                             |  28 ++-
 tools/testing/selftests/bpf/network_helpers.c |  28 +++
 tools/testing/selftests/bpf/network_helpers.h |   3 +
 .../selftests/bpf/prog_tests/lwt_helpers.h    |  29 ----
 .../bpf/prog_tests/xdp_context_test_run.c     | 163 ++++++++++++++++--
 .../selftests/bpf/progs/test_xdp_meta.c       |  56 +++---
 6 files changed, 230 insertions(+), 77 deletions(-)

-- 
2.43.0