Merge branch 'sctp-add-subscribe-per-asoc-and-sockopt-SCTP_EVENT'

Xin Long says:

====================
sctp: add subscribe per asoc and sockopt SCTP_EVENT

This patchset mainly adds the Event Subscription sockopt described in
rfc6525#section-6.2:

"Subscribing to events as described in [RFC6458] uses a setsockopt()
call with the SCTP_EVENT socket option.  This option takes the
following structure, which specifies the association, the event type
(using the same value found in the event type field), and an on/off
boolean.

  struct sctp_event {
    sctp_assoc_t se_assoc_id;
    uint16_t     se_type;
    uint8_t      se_on;
  };

The user fills in the se_type field with the same value found in the
strreset_type field, i.e., SCTP_STREAM_RESET_EVENT.  The user will
also fill in the se_assoc_id field with either the association to set
this event on (this field is ignored for one-to-one style sockets) or
one of the reserved constant values defined in [RFC6458].  Finally,
the se_on field is set with a 1 to enable the event or a 0 to disable
the event."

As for the old SCTP_EVENTS Option with struct sctp_event_subscribe,
it's being DEPRECATED.

v1->v2:
  - fix some key word in changelog that triggerred the filters at
    vger.kernel.org.
v2->v3:
  - fix an array out of bounds noticed by Neil in patch 1/4.
====================

Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>