[PATCH bpf-next/net v5 0/3] selftests/bpf: new MPTCP subflow subtest

[Matthieu Baerts (NGI0)]

In this series from Geliang, modifying MPTCP BPF selftests, we have:

- A new MPTCP subflow BPF program setting socket options per subflow: it
  looks better to have this old test program in the BPF selftests to
  track regressions and to serve as example.

  Note: Nicolas is no longer working at Tessares, but he did this work
  while working for them, and his email address is no longer available.

- A new hook in the same BPF program to do the verification step.

- A new MPTCP BPF subtest validating the new BPF program added in the
  first patch, with the help of the new hook added in the second patch.

Signed-off-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
---
Changes in v5:
- See the individual changelog for more details about them
- Patch 1/3: set TCP on the 2nd subflow
- Patch 2/3: new
- Patch 3/3: use the BPF program from patch 2/3 to do the validation
             instead of using ss.
- Link to v4: https://lore.kernel.org/r/20240805-upstream-bpf-next-20240506-mptcp-subflow-test-v4-0-2b4ca6994993@xxxxxxxxxx

Changes in v4:
- Drop former patch 2/3: MPTCP's pm_nl_ctl requires a new header file:
  - I will check later if it is possible to avoid having duplicated
    header files in tools/include/uapi, but no need to block this series
    for that. Patch 2/3 can be added later if needed.
- Patch 2/2: skip the test if 'ip mptcp' is not available.
- Link to v3: https://lore.kernel.org/r/20240703-upstream-bpf-next-20240506-mptcp-subflow-test-v3-0-ebdc2d494049@xxxxxxxxxx

Changes in v3:
- Sorry for the delay between v2 and v3, this series was conflicting
  with the "add netns helpers", but it looks like it is on hold:
  https://lore.kernel.org/cover.1715821541.git.tanggeliang@xxxxxxxxxx
- Patch 1/3 includes "bpf_tracing_net.h", introduced in between.
- New patch 2/3: "selftests/bpf: Add mptcp pm_nl_ctl link".
- Patch 3/3: use the tool introduced in patch 2/3 + SYS_NOFAIL() helper.
- Link to v2: https://lore.kernel.org/r/20240509-upstream-bpf-next-20240506-mptcp-subflow-test-v2-0-4048c2948665@xxxxxxxxxx

Changes in v2:
- Previous patches 1/4 and 2/4 have been dropped from this series:
  - 1/4: "selftests/bpf: Handle SIGINT when creating netns":
    - A new version, more generic and no longer specific to MPTCP BPF
      selftest will be sent later, as part of a new series. (Alexei)
  - 2/4: "selftests/bpf: Add RUN_MPTCP_TEST macro":
    - Removed, not to hide helper functions in macros. (Alexei)
- The commit message of patch 1/2 has been clarified to avoid some
  possible confusions spot by Alexei.
- Link to v1: https://lore.kernel.org/r/20240507-upstream-bpf-next-20240506-mptcp-subflow-test-v1-0-e2bcbdf49857@xxxxxxxxxx

---
Geliang Tang (2):
      selftests/bpf: Add getsockopt to inspect mptcp subflow
      selftests/bpf: Add mptcp subflow subtest

Nicolas Rybowski (1):
      selftests/bpf: Add mptcp subflow example

 MAINTAINERS                                       |   2 +-
 tools/testing/selftests/bpf/prog_tests/mptcp.c    | 126 +++++++++++++++++++++
 tools/testing/selftests/bpf/progs/mptcp_bpf.h     |  42 +++++++
 tools/testing/selftests/bpf/progs/mptcp_subflow.c | 128 ++++++++++++++++++++++
 4 files changed, 297 insertions(+), 1 deletion(-)
---
base-commit: 6b083650a37318112fb60c65fbb6070584f53d93
change-id: 20240506-upstream-bpf-next-20240506-mptcp-subflow-test-faef6654bfa3

Best regards,
-- 
Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>