sctp: add sender-side procedures for stream reconf ssn reset request chunk

Patch 6/6 is to implement sender-side procedures for the Outgoing and Incoming SSN Reset Request Parameter described in rfc6525 section 5.1.2 and 5.1.3

Patches 1-5/6 are ahead of it to define some apis and asoc members for it.

Note that with this patchset, asoc->reconf_enable has no chance yet to be set, until the patch "sctp: add get and set sockopt for reconf_enable" is applied in the future. As we can not just enable it when sctp is not capable of processing reconf chunk yet.

v1->v2:
- put these into a smaller group.
- rename some temporary variables in the codes.
- rename the titles of the commits and improve some changelogs.
v2->v3:
- re-split the patchset and make sure it has no dead codes for review.
v3->v4:
- move sctp_make_reconf() into patch 1/6 to avoid kbuild warning.
- drop unused struct sctp_strreset_req.

Xin Long (6):
sctp: add support for generating stream reconf ssn reset request chunk
sctp: add stream reconf timer
sctp: add stream reconf primitive
sctp: add reconf_enable in asoc ep and netns
sctp: add sockopt SCTP_ENABLE_STREAM_RESET
sctp: implement sender-side procedures for SSN Reset Request Parameter

 include/linux/sctp.h         |  27 +++++++++
 include/net/netns/sctp.h     |   3 +
 include/net/sctp/constants.h |   4 +-
 include/net/sctp/sctp.h      |   8 +++
 include/net/sctp/sm.h        |   8 ++-
 include/net/sctp/structs.h   |  21 ++++++-
 include/uapi/linux/sctp.h    |  18 ++++++
 net/sctp/associola.c         |  12 ++++
 net/sctp/endpointola.c       |   1 +
 net/sctp/outqueue.c          |  33 +++++++----
 net/sctp/primitive.c         |   3 +
 net/sctp/protocol.c          |   3 +
 net/sctp/sm_make_chunk.c     | 136 +++++++++++++++++++++++++++++++++++++++++++
 net/sctp/sm_sideeffect.c     |  32 ++++++++++
 net/sctp/sm_statefuns.c      |  41 +++++++++++++
 net/sctp/sm_statetable.c     |  40 +++++++++++++
 net/sctp/socket.c            | 113 +++++++++++++++++++++++++++++++++++
 net/sctp/stream.c            |  79 +++++++++++++++++++++++++
 net/sctp/transport.c         |  17 +++++-
 19 files changed, 583 insertions(+), 16 deletions(-)

2.1.0