Merge branch 'sctp-add-support-for-some-msg_control-options-from-RFC6458'

Xin Long says:

====================
sctp: add support for some msg_control options from RFC6458

This patchset is to add support for 3 msg_control options described
in RFC6458:

    5.3.7.  SCTP PR-SCTP Information Structure (SCTP_PRINFO)
    5.3.9.  SCTP Destination IPv4 Address Structure (SCTP_DSTADDRV4)
    5.3.10. SCTP Destination IPv6 Address Structure (SCTP_DSTADDRV6)

one send flag described in RFC6458:

    SCTP_SENDALL:  This flag, if set, will cause a one-to-many
    style socket to send the message to all associations that
    are currently established on this socket.  For the one-to-
    one style socket, this flag has no effect.

Note there is another msg_control option:

    5.3.8.  SCTP AUTH Information Structure (SCTP_AUTHINFO)

It's a little complicated, I will post it in another patchset after
this.
====================

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