- Patch 1: fix issue #544 where a middlebox drops MPTCP options after a
  3WHS on the additional subflow.

- Patch 2: a safety check is added when asking to do a fallback to do so
  only when allowed. If not, a new warning will be emitted.

Note that two new packetdrill tests have been added in a PR to cover
this case:

  https://github.com/multipath-tcp/packetdrill/pull/160

Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
Changes in v2:
- Squashed previous patches 1 and 2 (Paolo).
- Patch 1: no more special cases for csum (handled before) and inf map
  (Paolo).
- Link to v1: https://lore.kernel.org/r/20250217-mptcp-dss-drop-mpj-v1-0-d671d6b9a153@kernel.org

---
Matthieu Baerts (NGI0) (2):
      mptcp: reset when MPTCP opts are dropped after join
      mptcp: safety check before fallback

 net/mptcp/protocol.h |  2 ++
 net/mptcp/subflow.c  | 15 +--------------
 2 files changed, 3 insertions(+), 14 deletions(-)
---
base-commit: 3a7786db65e8f361a8fc8abcd3cfbe17411b8b7f
change-id: 20250205-mptcp-dss-drop-mpj-ec227f4ed942

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

On 2/18/25 12:24 PM, Matthieu Baerts (NGI0) wrote:
> - Patch 1: fix issue #544 where a middlebox drops MPTCP options after a
>   3WHS on the additional subflow.
> 
> - Patch 2: a safety check is added when asking to do a fallback to do so
>   only when allowed. If not, a new warning will be emitted.
> 
> Note that two new packetdrill tests have been added in a PR to cover
> this case:
> 
>   https://github.com/multipath-tcp/packetdrill/pull/160
> 
> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>

Acked-by: Paolo Abeni <pabeni@redhat.com>

Hi Paolo,

On 18/02/2025 17:24, Paolo Abeni wrote:
> On 2/18/25 12:24 PM, Matthieu Baerts (NGI0) wrote:
>> - Patch 1: fix issue #544 where a middlebox drops MPTCP options after a
>>   3WHS on the additional subflow.
>>
>> - Patch 2: a safety check is added when asking to do a fallback to do so
>>   only when allowed. If not, a new warning will be emitted.
>>
>> Note that two new packetdrill tests have been added in a PR to cover
>> this case:
>>
>>   https://github.com/multipath-tcp/packetdrill/pull/160
>>
>> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
> 
> Acked-by: Paolo Abeni <pabeni@redhat.com>

Thank you for this review!

Now in our tree (fixes for -net):

New patches for t/upstream-net and t/upstream:
- 1babdda71364: mptcp: reset when MPTCP opts are dropped after join
- 1e4711c4b02c: mptcp: safety check before fallback
- Results: 54ac5bb2f077..aba580cd4fc8 (export-net)
- Results: 4ba9db964049..3ee8e45b1642 (export)

Tests are now in progress:

- export-net:
https://github.com/multipath-tcp/mptcp_net-next/commit/2ea4756918f65f22b82d3134485d4c2842e3400f/checks
- export:
https://github.com/multipath-tcp/mptcp_net-next/commit/4f345f49f9f36636d9f8408b4a30b70f602b50ae/checks

Cheers,
Matt
-- 
Sponsored by the NGI0 Core fund.

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-normal (only bpftest_all): Success! ✅
- KVM Validation: btf-debug (only bpftest_all): Success! ✅
- Task: https://github.com/multipath-tcp/mptcp_net-next/actions/runs/13389741751

Initiator: Patchew Applier
Commits: https://github.com/multipath-tcp/mptcp_net-next/commits/031a27795787
Patchwork: https://patchwork.kernel.org/project/mptcp/list/?series=935069


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)