Subject: Re: [PATCH net-next 0/6] mptcp: Path manager mode selection

From: Jakub Kicinski <[email-masked]>
Date: Thu, 28 Apr 2022 18:57:39 -0700

On Wed, 27 Apr 2022 15:49:56 -0700 Mat Martineau wrote:
> MPTCP already has an in-kernel path manager (PM) to add and remove TCP
> subflows associated with a given MPTCP connection. This in-kernel PM has
> been designed to handle typical server-side use cases, but is not very
> flexible or configurable for client devices that may have more
> complicated policies to implement.
> 
> This patch series from the MPTCP tree is the first step toward adding a
> generic-netlink-based API for MPTCP path management, which a privileged
> userspace daemon will be able to use to control subflow
> establishment. These patches add a per-namespace sysctl to select the
> default PM type (in-kernel or userspace) for new MPTCP sockets. New
> self-tests confirm expected behavior when userspace PM is selected but
> there is no daemon available to handle existing MPTCP PM events.
> 
> Subsequent patch series (already staged in the MPTCP tree) will add the
> generic netlink path management API.

Could you link to those patches, maybe? Feels a little strange to add
this sysctl to switch to user space mode now, before we had a chance
to judg^W review the netlink interface.

Does the pm_type switch not fit more neatly into the netlink interface
itself?