In the previous post we have discussed the ancillary data - one of the ways to access SCTP specific protocol parameters and events. Today we will review another similar topic - the SCTP notifications. They are also received with recvmsg(), but you receive different kind of information. Ancillary data allowed us to get some SCTP specific parameters for the DATA chunk containing the payload, like stream number, association id, etc. With notifications you can access more general information about the association - e.g. receive event when it is established, when it is teared down, remote errors, etc.
SCTP notifications are described in Section 6 of RFC 6458. The implementation of Linux has got some really small differences from the specification, but they are in terms of structure/parameter names. I will try to list them, but even if I forget something you will easily notice them by yourself.