Re: [PATCH iproute2-next] mptcp: add implicit flag to the 'ip mptcp' inline help

[Stephen Hemminger <stephen@networkplumber.org>]

On Wed, 22 Oct 2025 16:49:41 +0200
Matthieu Baerts <matttbe@kernel.org> wrote:

> Hi Andrea,
> 
> Sorry, I'm reacting a bit too late here (but Stephen applied the patch
> very quickly :) ).
> 
> On 21/10/2025 21:26, Andrea Claudi wrote:
> > ip mptcp supports the implicit flag since commit 3a2535a41854 ("mptcp:
> > add support for implicit flag"), however this flag is not listed in the
> > command inline help.
> > 
> > Add the implicit flag to the inline help.  
> 
> I would rather not: as written in the man page (by you in the mentioned
> commit :) ) "Implicit endpoints cannot be created from user-space". Such
> endpoints can be created by the MPTCP in-kernel path-manager in some
> circumstances, but if the user-space cannot set the flag, then probably
> better not to add it in the command inline help, no?
> 
> If someone tries to create an "implicit" endpoint, the kernel will
> reject this request, see:
> 
> https://elixir.bootlin.com/linux/v6.17/source/net/mptcp/pm_kernel.c#L813
> 
> I can send a revert. I have other small changes to send.

Thanks I reverted it