mptcp: add support for fullmesh flag

The link kernel supports this endpoint flag since v5.15, let's
expose it to user-space. It allows creation on fullmesh topolgy
via MPTCP subflow.

Additionally update the related man-page, clarifying the behavior
of related options.

Acked-by: Mat Martineau <>
Signed-off-by: Paolo Abeni <>
Signed-off-by: David Ahern <>
2 files changed