Merge branch 'mptcp-userspace-path-manager-prerequisites'

Mat Martineau says:

====================
mptcp: Userspace path manager prerequisites

This series builds upon the path manager mode selection changes merged
in 4994d4fa99ba ("Merge branch 'mptcp-path-manager-mode-selection'") to
further modify the path manager code in preparation for adding the new
netlink commands to announce/remove advertised addresses and
create/destroy subflows of an MPTCP connection. The third and final
patch series for the userspace path manager will implement those
commands as discussed in
https://lore.kernel.org/netdev/23ff3b49-2563-1874-fa35-3af55d3088e7@linux.intel.com/#r

Patches 1, 5, and 7 remove some internal constraints on path managers
(in general) without changing in-kernel PM behavior.

Patch 2 adds a self test to validate MPTCP address advertisement ack
behavior.

Patches 3, 4, and 6 add new attributes to existing MPTCP netlink events
and track internal state for populating those attributes.
====================

Link: https://lore.kernel.org/r/20220502205237.129297-1-mathew.j.martineau@linux.intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>