mptcp: add and use MIB counter infrastructure

Exported via same /proc file as the Linux TCP MIB counters, so "netstat -s"
or "nstat" will show them automatically.

The MPTCP MIB counters are allocated in a distinct pcpu area in order to
avoid bloating/wasting TCP pcpu memory.

Counters are allocated once the first MPTCP socket is created in a
network namespace and free'd on exit.

If no sockets have been allocated, all-zero mptcp counters are shown.

The MIB counter list is taken from the multipath-tcp.org kernel, but
only a few counters have been picked up so far.  The counter list can
be increased at any time later on.

v2 -> v3:
 - remove 'inline' in foo.c files (David S. Miller)

Co-developed-by: Paolo Abeni <[email protected]>
Signed-off-by: Paolo Abeni <[email protected]>
Signed-off-by: Florian Westphal <[email protected]>
Signed-off-by: Mat Martineau <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

0 files changed, 0 insertions, 0 deletions