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Clarify the interleaving at the sender side. Interleaving ordered and unordered messages on the sender side is not allowed unless a new interleaving level is defined at the receiver side.

Make clear that the receiver MUST NOT make any assumptions about TSN assignments. It should also be noted that the sender MUST ensure that the receiver can make progress. One way of doing this is to assign later fragments higher TSNs and send TSNs out in sequence.

Should we allow the interleaving of an ordered and unordered message? SCTP_FRAGMENT_INTERLEAVE isn't clear about this. Clarify it!

Describe what happens when an application tries to select an stream scheduler requiring I-DATA support, but this isn't negotiated. EINVAL might the appropriate errno.
Describe what happens if the application selects a stream scheduler requiring I-DATA support before the association is established (on a listening socket, for example), and then the association is established without I-DATA support (since the peer doesn't support it).

This issue was brought up by Marcelo on the tsvwg mailing list.

Remove some_taken from struct sctp_queued_to_read. Double check if some other conditions needs to be considered.

Section 2.1 contains:

However, the lower 16-bit of the MID can be used as the SSN if necessary.

This should be moved to the Socket API Considerations making clear that the data structures exposing the SSN are not changed.

The SSN is exposed in

• struct sctp_sndrcvinfo as specified in SCTP Header Information Structure (SCTP_SNDRCV) - DEPRECATED
• struct sctp_extrcvinfo as specified in Extended SCTP Header Information Structure (SCTP_EXTRCV) - DEPRECATED
• struct sctp_rcvinfo as specified in SCTP Receive Information Structure (SCTP_RCVINFO)

It currently removes the DATA chunk when reporting.
While there, it also reports any padding.

Make clear that either I-FORWARD-TSN or FORWARD-TSN is used. I-FORWARD-TSN is only used in combination with I-DATA. Make also clear how support for I-FORWARD-TSN is negotiated.

Replace

Since most schedulers require late TSN assignment, it should be noted
 that the implementation of [RFC6525] needs to handle this.

by

Since most schedulers, especially all schedulers supporting user message
interleaving, require late TSN assignment, it should be noted that the
implementation of [RFC6525] needs to handle this.

I don't fully understand the description of assoc_id in section 4.3.1.

This parameter is ignored for one-to-one style sockets.
For one-to-many style sockets, this parameter indicates upon which association
the user is performing an action.

So far so good.

The special sctp_assoc_t SCTP_FUTURE_ASSOC can also be used,
it is an error to use SCTP_{CURRENT|ALL}_ASSOC in assoc_id.

1. Why also if SCTP_CURRENT_ASSOC and SCTP_ALL_ASSOC are invalid? What does also refer to?
2. If everything but SCTP_FUTURE_ASSOC is invalid, why not just state exactly that?
3. The sentence could probably be split up into two.

(Let me know if I should write this on the mailing list.)

In sctp_choose_boundspecific_stcb
for (laddr = stcb->asoc.last_used_address; laddr;
laddr = LIST_NEXT(laddr, sctp_nxt_addr)) {
if (laddr->ifa == NULL) {
/* address has been removed /
continue;
}
if (laddr->action == SCTP_DEL_IP_ADDRESS) {
/ address is being deleted /
continue;
}
sifa = sctp_is_ifa_addr_preferred(laddr->ifa, dest_is_loop, dest_is_priv, fam);
if (sifa == NULL)
continue;
if (((non_asoc_addr_ok == 0) &&
(sctp_is_addr_restricted2(stcb, sifa))) ||
(non_asoc_addr_ok &&
(sctp_is_addr_restricted2(stcb, sifa)) &&
(!sctp_is_addr_pending(stcb, sifa)))) {
/ on the no-no list */
continue;
}
stcb->asoc.last_used_address = laddr;
SCTP_TCB_UNLOCK(stcb);
atomic_add_int(&sifa->refcount, 1);
return (sifa);
}
if (start_at_beginning == 0) {
stcb->asoc.last_used_address = NULL;
goto sctp_from_the_top;
}
My application was crashing when in this part of code, when try to change some config related to sctp in my application and the reloading it. I some times see multiple threads are in this part of code, however they belong to different sctp connections.