Recently, a few issues have been discovered around the creation of
additional subflows. Without these counters, it was difficult to point
out the reason why some subflows were not created as expected.

In patch 2, all error paths from __mptcp_subflow_connect() are covered,
except the one related to the 'fully established mode', because it
should only happen with the userspace PM, which will propagate the error
in this  case (ENOTCONN).

These new counters are also verified in the MPTCP Join selftest in patch
5.

While at it, a few other patches are improving the MPJoin selftests:

 - Patch 1: a fix when using an old kernel
 - Patch 3: reduce the number of positional parameters
 - Patch 4: only one line for the 'join' checks, instead of 3
 - Patch 6: more explicit check names, instead of sometimes too cryptic
            ones: rtx, ptx, ftx, ctx, fclzrx, sum
 - Patch 7: specify client/server instead of 'invert' for some checks
            not suggesting one direction
 - Patch 8: mute errors of mptcp_connect when ran in the background

Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
Changes in v3:
- Patch 2: remove fully estab error
- Patch 5: force bind error + always validate join tx
- New patches: 1, 3, 4, 6, 7, 8.
- Link to v2: https://lore.kernel.org/r/20240729-mptcp-join-tx-mib-v2-0-8ace70fd407a@kernel.org

Changes in v2:
- Patch 1/2: Add "ERR" suffix in variable names. (Geliang)
- Link to v1: https://lore.kernel.org/r/20240726-mptcp-join-tx-mib-v1-0-7f2149ba0dcf@kernel.org

---
Matthieu Baerts (NGI0) (8):
      selftests: mptcp: join: no extra msg if no counter
      mptcp: MIB counters for sent MP_JOIN
      selftests: mptcp: join: reduce join_nr params
      selftests: mptcp: join: one line for join check
      selftests: mptcp: join: validate MPJ SYN TX MIB counters
      selftests: mptcp: join: more explicit check name
      selftests: mptcp: join: specify host being checked
      selftests: mptcp: join: mute errors when ran in the background

 net/mptcp/mib.c                                 |   4 +
 net/mptcp/mib.h                                 |   4 +
 net/mptcp/subflow.c                             |  21 +-
 tools/testing/selftests/net/mptcp/mptcp_join.sh | 308 +++++++++++++++---------
 4 files changed, 226 insertions(+), 111 deletions(-)
---
base-commit: d8ff9c0319613035c0fbc35dc2ce12f8f2948dcc
change-id: 20240724-mptcp-join-tx-mib-84e21ea4b236

Best regards,
-- 
Matthieu Baerts (NGI0) <matttbe@kernel.org>

Hi Matthieu,

Thank you for your modifications, that's great!

Our CI did some validations and here is its report:

- KVM Validation: normal: Success! ✅
- KVM Validation: debug: Success! ✅
- KVM Validation: btf (only bpftest_all): Success! ✅
- Task: https://github.com/multipath-tcp/mptcp_net-next/actions/runs/10265659749

Initiator: Patchew Applier
Commits: https://github.com/multipath-tcp/mptcp_net-next/commits/a07e36f8ecfa
Patchwork: https://patchwork.kernel.org/project/mptcp/list/?series=877027


If there are some issues, you can reproduce them using the same environment as
the one used by the CI thanks to a docker image, e.g.:

    $ cd [kernel source code]
    $ docker run -v "${PWD}:${PWD}:rw" -w "${PWD}" --privileged --rm -it \
        --pull always mptcp/mptcp-upstream-virtme-docker:latest \
        auto-normal

For more details:

    https://github.com/multipath-tcp/mptcp-upstream-virtme-docker


Please note that despite all the efforts that have been already done to have a
stable tests suite when executed on a public CI like here, it is possible some
reported issues are not due to your modifications. Still, do not hesitate to
help us improve that ;-)

Cheers,
MPTCP GH Action bot
Bot operated by Matthieu Baerts (NGI0 Core)