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

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Message-ID: <946ceea8-eb58-4140-aa5a-94605cd697ce@kernel.org>
Date: Wed, 22 Oct 2025 16:49:41 +0200
From: Matthieu Baerts <matttbe@...nel.org>
To: Andrea Claudi <aclaudi@...hat.com>,
 Stephen Hemminger <stephen@...workplumber.org>
Cc: David Ahern <dsahern@...nel.org>, netdev@...r.kernel.org,
 MPTCP Linux <mptcp@...ts.linux.dev>
Subject: Re: [PATCH iproute2-next] mptcp: add implicit flag to the 'ip mptcp'
 inline help

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.

@Stephen: while at it, would it be OK if I also add an entry for files
linked related to MPTCP in the MAINTAINERS file?

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