SCTP Invalid notification length about libdatachannel HOT 4 CLOSED

Thanks for reporting the issue. Given the symptoms you describe, it seems to me the behavior you observe here is that when the message is long enough the first roughly 2^16 bytes might be marked as a SCTP notification, therefore triggering the length sanity check discarding it, in which case you receive only what's left.

It's probably an issue with how usrsctp API is handled (it's a bit tricky to use correctly). The option SCTP_FRAGMENT_INTERLEAVE is set to 0 which should prevent messages being interleaved with event notifications (as stated in RFC 6458), but that behavior might change for messages bigger than 2^16.

The involved code is here:

from libdatachannel.

Could you please check if separated SCTP notifications and messages on branch usrsctp-fix-notifications prevents the issue?

from libdatachannel.

Hello.
It seems the problem is fixed in the branch you linked.
I was unable to reproduce the issue after about 10k of 200kbytes messages.

from libdatachannel.

Excellent, I'll merge the fix.

from libdatachannel.