Merge branch 'mptcp-Add-port-parameter-to-ADD_ADDR-option'

Mat Martineau says:

====================
mptcp: Add port parameter to ADD_ADDR option

The ADD_ADDR MPTCP option is used to announce available IP addresses
that a peer may connect to when adding more TCP subflows to an existing
MPTCP connection. There is an optional port number field in that
ADD_ADDR header, and this patch set adds capability for that port number
to be sent and received.

Patches 1, 2, and 4 refactor existing ADD_ADDR code to simplify implementation
of port number support.

Patches 3 and 5 are the main functional changes, for sending and
receiving the port number in the MPTCP ADD_ADDR option.

Patch 6 sends the ADD_ADDR option with port number on a bare TCP ACK,
since the extra length of the option may run in to cases where
sufficient TCP option space is not available on a data packet.

Patch 7 plumbs in port number support for the in-kernel MPTCP path
manager.

Patches 8-11 add some optional debug output and a little more cleanup
refactoring.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>