Fixes to ECN in SCTP.

1) ECN was on an association basis, this is incorrect and
   will not work with CMT or for that matter if the user
   is sending to multiple addresses. This commit makes
   ECN on a per path basis.
2) Adopt the new format for the ECN internet draft. This also
   maintains compatability with old format chunks as well.
3) Keep track of the real time of a RTT down to micro seconds.
   For some future conditional features (for like a data center
   this is good information to have).
MFC after:	1 month

0 files changed, 0 insertions, 0 deletions