This is just a simple fix to ignore unknown endpoint flags. Recently, a
new "laminar" flag has been added. It can be set on older kernel
versions without effects -- which is good -- but it is strange to report
it in the endpoints dumps if it is not supported.

  # uname -r
  6.17.9
  # ip mptcp endpoint add 1.2.3.4 laminar  # not supported on v6.17
  # ip mptcp endpoint
  1.2.3.4 id 1 laminar

Patch 1 fixes that, while Patch 2 validates that.

Patch 3 is for mptcp-next, to correctly follow the specs and accept u32
flags instead of u8. This doesn't change anything, but avoids
confusions.

Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
---
Matthieu Baerts (NGI0) (3):
      mptcp: pm: ignore unknown endpoint flags
      selftests: mptcp: pm: ensure unknown flags are ignored
      mptcp: pm: align endpoint flags size with the NL specs

 include/uapi/linux/mptcp.h                      |  1 +
 net/mptcp/pm_netlink.c                          |  3 ++-
 net/mptcp/protocol.h                            |  4 ++--
 tools/testing/selftests/net/mptcp/pm_netlink.sh |  4 ++++
 tools/testing/selftests/net/mptcp/pm_nl_ctl.c   | 11 +++++++++++
 5 files changed, 20 insertions(+), 3 deletions(-)
---
base-commit: 690b1c68fd1e566ffa60fec98e09292cc9f04a3a
change-id: 20251125-mptcp-pm-kern-drop-unknown-flags-e4ec71df02e7

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

On Wed, 26 Nov 2025, Matthieu Baerts (NGI0) wrote:

> This is just a simple fix to ignore unknown endpoint flags. Recently, a
> new "laminar" flag has been added. It can be set on older kernel
> versions without effects -- which is good -- but it is strange to report
> it in the endpoints dumps if it is not supported.
>
>  # uname -r
>  6.17.9
>  # ip mptcp endpoint add 1.2.3.4 laminar  # not supported on v6.17
>  # ip mptcp endpoint
>  1.2.3.4 id 1 laminar
>
> Patch 1 fixes that, while Patch 2 validates that.
>
> Patch 3 is for mptcp-next, to correctly follow the specs and accept u32
> flags instead of u8. This doesn't change anything, but avoids
> confusions.
>
> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
> ---
> Matthieu Baerts (NGI0) (3):
>      mptcp: pm: ignore unknown endpoint flags
>      selftests: mptcp: pm: ensure unknown flags are ignored
>      mptcp: pm: align endpoint flags size with the NL specs

Hi Matthieu!

All three patches LGTM:

Reviewed-by: Mat Martineau <martineau@kernel.org>

See my comment on patch 2 regarding an additional fourth patch for 
net-next.

Thanks,
Mat


>
> include/uapi/linux/mptcp.h                      |  1 +
> net/mptcp/pm_netlink.c                          |  3 ++-
> net/mptcp/protocol.h                            |  4 ++--
> tools/testing/selftests/net/mptcp/pm_netlink.sh |  4 ++++
> tools/testing/selftests/net/mptcp/pm_nl_ctl.c   | 11 +++++++++++
> 5 files changed, 20 insertions(+), 3 deletions(-)
> ---
> base-commit: 690b1c68fd1e566ffa60fec98e09292cc9f04a3a
> change-id: 20251125-mptcp-pm-kern-drop-unknown-flags-e4ec71df02e7
>
> 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 (except selftest_mptcp_join): Success! ✅
- KVM Validation: normal (only selftest_mptcp_join): Success! ✅
- KVM Validation: debug (except selftest_mptcp_join): Unstable: 1 failed test(s): packetdrill_sockopts 🔴
- KVM Validation: debug (only selftest_mptcp_join): 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/19714326364

Initiator: Patchew Applier
Commits: https://github.com/multipath-tcp/mptcp_net-next/commits/2a19986e53c8
Patchwork: https://patchwork.kernel.org/project/mptcp/list/?series=1027994


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)