1 /* SCTP kernel implementation
2 * (C) Copyright IBM Corp. 2001, 2004
3 * Copyright (c) 1999-2000 Cisco, Inc.
4 * Copyright (c) 1999-2001 Motorola, Inc.
5 * Copyright (c) 2001 Intel Corp.
6 * Copyright (c) 2001 Nokia, Inc.
7 * Copyright (c) 2001 La Monte H.P. Yarroll
9 * This abstraction carries sctp events to the ULP (sockets).
11 * This SCTP implementation is free software;
12 * you can redistribute it and/or modify it under the terms of
13 * the GNU General Public License as published by
14 * the Free Software Foundation; either version 2, or (at your option)
17 * This SCTP implementation is distributed in the hope that it
18 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
19 * ************************
20 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
21 * See the GNU General Public License for more details.
23 * You should have received a copy of the GNU General Public License
24 * along with GNU CC; see the file COPYING. If not, write to
25 * the Free Software Foundation, 59 Temple Place - Suite 330,
26 * Boston, MA 02111-1307, USA.
28 * Please send any bug reports or fixes you make to the
30 * lksctp developers <lksctp-developers@lists.sourceforge.net>
32 * Or submit a bug report through the following website:
33 * http://www.sf.net/projects/lksctp
35 * Written or modified by:
36 * Jon Grimm <jgrimm@us.ibm.com>
37 * La Monte H.P. Yarroll <piggy@acm.org>
38 * Sridhar Samudrala <sri@us.ibm.com>
40 * Any bugs reported given to us we will try to fix... any fixes shared will
41 * be incorporated into the next SCTP release.
44 #include <linux/slab.h>
45 #include <linux/types.h>
46 #include <linux/skbuff.h>
48 #include <net/sctp/structs.h>
49 #include <net/sctp/sctp.h>
50 #include <net/sctp/sm.h>
52 /* Forward declarations for internal helpers. */
53 static struct sctp_ulpevent * sctp_ulpq_reasm(struct sctp_ulpq *ulpq,
54 struct sctp_ulpevent *);
55 static struct sctp_ulpevent * sctp_ulpq_order(struct sctp_ulpq *,
56 struct sctp_ulpevent *);
57 static void sctp_ulpq_reasm_drain(struct sctp_ulpq *ulpq);
59 /* 1st Level Abstractions */
61 /* Initialize a ULP queue from a block of memory. */
62 struct sctp_ulpq *sctp_ulpq_init(struct sctp_ulpq *ulpq,
63 struct sctp_association *asoc)
65 memset(ulpq, 0, sizeof(struct sctp_ulpq));
68 skb_queue_head_init(&ulpq->reasm);
69 skb_queue_head_init(&ulpq->lobby);
77 /* Flush the reassembly and ordering queues. */
78 void sctp_ulpq_flush(struct sctp_ulpq *ulpq)
81 struct sctp_ulpevent *event;
83 while ((skb = __skb_dequeue(&ulpq->lobby)) != NULL) {
84 event = sctp_skb2event(skb);
85 sctp_ulpevent_free(event);
88 while ((skb = __skb_dequeue(&ulpq->reasm)) != NULL) {
89 event = sctp_skb2event(skb);
90 sctp_ulpevent_free(event);
95 /* Dispose of a ulpqueue. */
96 void sctp_ulpq_free(struct sctp_ulpq *ulpq)
98 sctp_ulpq_flush(ulpq);
103 /* Process an incoming DATA chunk. */
104 int sctp_ulpq_tail_data(struct sctp_ulpq *ulpq, struct sctp_chunk *chunk,
107 struct sk_buff_head temp;
108 struct sctp_ulpevent *event;
111 /* Create an event from the incoming chunk. */
112 event = sctp_ulpevent_make_rcvmsg(chunk->asoc, chunk, gfp);
116 /* Do reassembly if needed. */
117 event = sctp_ulpq_reasm(ulpq, event);
119 /* Do ordering if needed. */
120 if ((event) && (event->msg_flags & MSG_EOR)){
121 /* Create a temporary list to collect chunks on. */
122 skb_queue_head_init(&temp);
123 __skb_queue_tail(&temp, sctp_event2skb(event));
125 event = sctp_ulpq_order(ulpq, event);
128 /* Send event to the ULP. 'event' is the sctp_ulpevent for
129 * very first SKB on the 'temp' list.
132 event_eor = (event->msg_flags & MSG_EOR) ? 1 : 0;
133 sctp_ulpq_tail_event(ulpq, event);
139 /* Add a new event for propagation to the ULP. */
140 /* Clear the partial delivery mode for this socket. Note: This
141 * assumes that no association is currently in partial delivery mode.
143 int sctp_clear_pd(struct sock *sk, struct sctp_association *asoc)
145 struct sctp_sock *sp = sctp_sk(sk);
147 if (atomic_dec_and_test(&sp->pd_mode)) {
148 /* This means there are no other associations in PD, so
149 * we can go ahead and clear out the lobby in one shot
151 if (!skb_queue_empty(&sp->pd_lobby)) {
152 struct list_head *list;
153 sctp_skb_list_tail(&sp->pd_lobby, &sk->sk_receive_queue);
154 list = (struct list_head *)&sctp_sk(sk)->pd_lobby;
155 INIT_LIST_HEAD(list);
159 /* There are other associations in PD, so we only need to
160 * pull stuff out of the lobby that belongs to the
161 * associations that is exiting PD (all of its notifications
164 if (!skb_queue_empty(&sp->pd_lobby) && asoc) {
165 struct sk_buff *skb, *tmp;
166 struct sctp_ulpevent *event;
168 sctp_skb_for_each(skb, &sp->pd_lobby, tmp) {
169 event = sctp_skb2event(skb);
170 if (event->asoc == asoc) {
171 __skb_unlink(skb, &sp->pd_lobby);
172 __skb_queue_tail(&sk->sk_receive_queue,
182 /* Set the pd_mode on the socket and ulpq */
183 static void sctp_ulpq_set_pd(struct sctp_ulpq *ulpq)
185 struct sctp_sock *sp = sctp_sk(ulpq->asoc->base.sk);
187 atomic_inc(&sp->pd_mode);
191 /* Clear the pd_mode and restart any pending messages waiting for delivery. */
192 static int sctp_ulpq_clear_pd(struct sctp_ulpq *ulpq)
195 sctp_ulpq_reasm_drain(ulpq);
196 return sctp_clear_pd(ulpq->asoc->base.sk, ulpq->asoc);
199 /* If the SKB of 'event' is on a list, it is the first such member
202 int sctp_ulpq_tail_event(struct sctp_ulpq *ulpq, struct sctp_ulpevent *event)
204 struct sock *sk = ulpq->asoc->base.sk;
205 struct sk_buff_head *queue, *skb_list;
206 struct sk_buff *skb = sctp_event2skb(event);
209 skb_list = (struct sk_buff_head *) skb->prev;
211 /* If the socket is just going to throw this away, do not
212 * even try to deliver it.
214 if (sock_flag(sk, SOCK_DEAD) || (sk->sk_shutdown & RCV_SHUTDOWN))
217 /* Check if the user wishes to receive this event. */
218 if (!sctp_ulpevent_is_enabled(event, &sctp_sk(sk)->subscribe))
221 /* If we are in partial delivery mode, post to the lobby until
222 * partial delivery is cleared, unless, of course _this_ is
223 * the association the cause of the partial delivery.
226 if (atomic_read(&sctp_sk(sk)->pd_mode) == 0) {
227 queue = &sk->sk_receive_queue;
230 /* If the association is in partial delivery, we
231 * need to finish delivering the partially processed
232 * packet before passing any other data. This is
233 * because we don't truly support stream interleaving.
235 if ((event->msg_flags & MSG_NOTIFICATION) ||
236 (SCTP_DATA_NOT_FRAG ==
237 (event->msg_flags & SCTP_DATA_FRAG_MASK)))
238 queue = &sctp_sk(sk)->pd_lobby;
240 clear_pd = event->msg_flags & MSG_EOR;
241 queue = &sk->sk_receive_queue;
245 * If fragment interleave is enabled, we
246 * can queue this to the receive queue instead
249 if (sctp_sk(sk)->frag_interleave)
250 queue = &sk->sk_receive_queue;
252 queue = &sctp_sk(sk)->pd_lobby;
256 /* If we are harvesting multiple skbs they will be
257 * collected on a list.
260 sctp_skb_list_tail(skb_list, queue);
262 __skb_queue_tail(queue, skb);
264 /* Did we just complete partial delivery and need to get
265 * rolling again? Move pending data to the receive
269 sctp_ulpq_clear_pd(ulpq);
271 if (queue == &sk->sk_receive_queue)
272 sk->sk_data_ready(sk, 0);
277 sctp_queue_purge_ulpevents(skb_list);
279 sctp_ulpevent_free(event);
284 /* 2nd Level Abstractions */
286 /* Helper function to store chunks that need to be reassembled. */
287 static void sctp_ulpq_store_reasm(struct sctp_ulpq *ulpq,
288 struct sctp_ulpevent *event)
291 struct sctp_ulpevent *cevent;
296 /* See if it belongs at the end. */
297 pos = skb_peek_tail(&ulpq->reasm);
299 __skb_queue_tail(&ulpq->reasm, sctp_event2skb(event));
303 /* Short circuit just dropping it at the end. */
304 cevent = sctp_skb2event(pos);
306 if (TSN_lt(ctsn, tsn)) {
307 __skb_queue_tail(&ulpq->reasm, sctp_event2skb(event));
311 /* Find the right place in this list. We store them by TSN. */
312 skb_queue_walk(&ulpq->reasm, pos) {
313 cevent = sctp_skb2event(pos);
316 if (TSN_lt(tsn, ctsn))
320 /* Insert before pos. */
321 __skb_queue_before(&ulpq->reasm, pos, sctp_event2skb(event));
325 /* Helper function to return an event corresponding to the reassembled
327 * This routine creates a re-assembled skb given the first and last skb's
328 * as stored in the reassembly queue. The skb's may be non-linear if the sctp
329 * payload was fragmented on the way and ip had to reassemble them.
330 * We add the rest of skb's to the first skb's fraglist.
332 static struct sctp_ulpevent *sctp_make_reassembled_event(struct net *net,
333 struct sk_buff_head *queue, struct sk_buff *f_frag,
334 struct sk_buff *l_frag)
337 struct sk_buff *new = NULL;
338 struct sctp_ulpevent *event;
339 struct sk_buff *pnext, *last;
340 struct sk_buff *list = skb_shinfo(f_frag)->frag_list;
342 /* Store the pointer to the 2nd skb */
343 if (f_frag == l_frag)
348 /* Get the last skb in the f_frag's frag_list if present. */
349 for (last = list; list; last = list, list = list->next);
351 /* Add the list of remaining fragments to the first fragments
357 if (skb_cloned(f_frag)) {
358 /* This is a cloned skb, we can't just modify
359 * the frag_list. We need a new skb to do that.
360 * Instead of calling skb_unshare(), we'll do it
361 * ourselves since we need to delay the free.
363 new = skb_copy(f_frag, GFP_ATOMIC);
365 return NULL; /* try again later */
367 sctp_skb_set_owner_r(new, f_frag->sk);
369 skb_shinfo(new)->frag_list = pos;
371 skb_shinfo(f_frag)->frag_list = pos;
374 /* Remove the first fragment from the reassembly queue. */
375 __skb_unlink(f_frag, queue);
377 /* if we did unshare, then free the old skb and re-assign */
387 /* Update the len and data_len fields of the first fragment. */
388 f_frag->len += pos->len;
389 f_frag->data_len += pos->len;
391 /* Remove the fragment from the reassembly queue. */
392 __skb_unlink(pos, queue);
394 /* Break if we have reached the last fragment. */
401 event = sctp_skb2event(f_frag);
402 SCTP_INC_STATS(net, SCTP_MIB_REASMUSRMSGS);
408 /* Helper function to check if an incoming chunk has filled up the last
409 * missing fragment in a SCTP datagram and return the corresponding event.
411 static struct sctp_ulpevent *sctp_ulpq_retrieve_reassembled(struct sctp_ulpq *ulpq)
414 struct sctp_ulpevent *cevent;
415 struct sk_buff *first_frag = NULL;
416 __u32 ctsn, next_tsn;
417 struct sctp_ulpevent *retval = NULL;
418 struct sk_buff *pd_first = NULL;
419 struct sk_buff *pd_last = NULL;
421 struct sctp_association *asoc;
424 /* Initialized to 0 just to avoid compiler warning message. Will
425 * never be used with this value. It is referenced only after it
426 * is set when we find the first fragment of a message.
430 /* The chunks are held in the reasm queue sorted by TSN.
431 * Walk through the queue sequentially and look for a sequence of
432 * fragmented chunks that complete a datagram.
433 * 'first_frag' and next_tsn are reset when we find a chunk which
434 * is the first fragment of a datagram. Once these 2 fields are set
435 * we expect to find the remaining middle fragments and the last
436 * fragment in order. If not, first_frag is reset to NULL and we
437 * start the next pass when we find another first fragment.
439 * There is a potential to do partial delivery if user sets
440 * SCTP_PARTIAL_DELIVERY_POINT option. Lets count some things here
441 * to see if can do PD.
443 skb_queue_walk(&ulpq->reasm, pos) {
444 cevent = sctp_skb2event(pos);
447 switch (cevent->msg_flags & SCTP_DATA_FRAG_MASK) {
448 case SCTP_DATA_FIRST_FRAG:
449 /* If this "FIRST_FRAG" is the first
450 * element in the queue, then count it towards
453 if (pos == ulpq->reasm.next) {
467 case SCTP_DATA_MIDDLE_FRAG:
468 if ((first_frag) && (ctsn == next_tsn)) {
478 case SCTP_DATA_LAST_FRAG:
479 if (first_frag && (ctsn == next_tsn))
489 /* Make sure we can enter partial deliver.
490 * We can trigger partial delivery only if framgent
491 * interleave is set, or the socket is not already
492 * in partial delivery.
494 if (!sctp_sk(asoc->base.sk)->frag_interleave &&
495 atomic_read(&sctp_sk(asoc->base.sk)->pd_mode))
498 cevent = sctp_skb2event(pd_first);
499 pd_point = sctp_sk(asoc->base.sk)->pd_point;
500 if (pd_point && pd_point <= pd_len) {
501 retval = sctp_make_reassembled_event(sock_net(asoc->base.sk),
506 sctp_ulpq_set_pd(ulpq);
512 retval = sctp_make_reassembled_event(sock_net(ulpq->asoc->base.sk),
513 &ulpq->reasm, first_frag, pos);
515 retval->msg_flags |= MSG_EOR;
519 /* Retrieve the next set of fragments of a partial message. */
520 static struct sctp_ulpevent *sctp_ulpq_retrieve_partial(struct sctp_ulpq *ulpq)
522 struct sk_buff *pos, *last_frag, *first_frag;
523 struct sctp_ulpevent *cevent;
524 __u32 ctsn, next_tsn;
526 struct sctp_ulpevent *retval;
528 /* The chunks are held in the reasm queue sorted by TSN.
529 * Walk through the queue sequentially and look for the first
530 * sequence of fragmented chunks.
533 if (skb_queue_empty(&ulpq->reasm))
536 last_frag = first_frag = NULL;
541 skb_queue_walk(&ulpq->reasm, pos) {
542 cevent = sctp_skb2event(pos);
545 switch (cevent->msg_flags & SCTP_DATA_FRAG_MASK) {
546 case SCTP_DATA_FIRST_FRAG:
550 case SCTP_DATA_MIDDLE_FRAG:
555 } else if (next_tsn == ctsn) {
561 case SCTP_DATA_LAST_FRAG:
564 else if (ctsn != next_tsn)
574 /* We have the reassembled event. There is no need to look
578 retval = sctp_make_reassembled_event(sock_net(ulpq->asoc->base.sk),
579 &ulpq->reasm, first_frag, last_frag);
580 if (retval && is_last)
581 retval->msg_flags |= MSG_EOR;
587 /* Helper function to reassemble chunks. Hold chunks on the reasm queue that
590 static struct sctp_ulpevent *sctp_ulpq_reasm(struct sctp_ulpq *ulpq,
591 struct sctp_ulpevent *event)
593 struct sctp_ulpevent *retval = NULL;
595 /* Check if this is part of a fragmented message. */
596 if (SCTP_DATA_NOT_FRAG == (event->msg_flags & SCTP_DATA_FRAG_MASK)) {
597 event->msg_flags |= MSG_EOR;
601 sctp_ulpq_store_reasm(ulpq, event);
603 retval = sctp_ulpq_retrieve_reassembled(ulpq);
607 /* Do not even bother unless this is the next tsn to
611 ctsnap = sctp_tsnmap_get_ctsn(&ulpq->asoc->peer.tsn_map);
612 if (TSN_lte(ctsn, ctsnap))
613 retval = sctp_ulpq_retrieve_partial(ulpq);
619 /* Retrieve the first part (sequential fragments) for partial delivery. */
620 static struct sctp_ulpevent *sctp_ulpq_retrieve_first(struct sctp_ulpq *ulpq)
622 struct sk_buff *pos, *last_frag, *first_frag;
623 struct sctp_ulpevent *cevent;
624 __u32 ctsn, next_tsn;
625 struct sctp_ulpevent *retval;
627 /* The chunks are held in the reasm queue sorted by TSN.
628 * Walk through the queue sequentially and look for a sequence of
629 * fragmented chunks that start a datagram.
632 if (skb_queue_empty(&ulpq->reasm))
635 last_frag = first_frag = NULL;
639 skb_queue_walk(&ulpq->reasm, pos) {
640 cevent = sctp_skb2event(pos);
643 switch (cevent->msg_flags & SCTP_DATA_FRAG_MASK) {
644 case SCTP_DATA_FIRST_FRAG:
653 case SCTP_DATA_MIDDLE_FRAG:
656 if (ctsn == next_tsn) {
663 case SCTP_DATA_LAST_FRAG:
675 /* We have the reassembled event. There is no need to look
679 retval = sctp_make_reassembled_event(sock_net(ulpq->asoc->base.sk),
680 &ulpq->reasm, first_frag, last_frag);
685 * Flush out stale fragments from the reassembly queue when processing
688 * RFC 3758, Section 3.6
690 * After receiving and processing a FORWARD TSN, the data receiver MUST
691 * take cautions in updating its re-assembly queue. The receiver MUST
692 * remove any partially reassembled message, which is still missing one
693 * or more TSNs earlier than or equal to the new cumulative TSN point.
694 * In the event that the receiver has invoked the partial delivery API,
695 * a notification SHOULD also be generated to inform the upper layer API
696 * that the message being partially delivered will NOT be completed.
698 void sctp_ulpq_reasm_flushtsn(struct sctp_ulpq *ulpq, __u32 fwd_tsn)
700 struct sk_buff *pos, *tmp;
701 struct sctp_ulpevent *event;
704 if (skb_queue_empty(&ulpq->reasm))
707 skb_queue_walk_safe(&ulpq->reasm, pos, tmp) {
708 event = sctp_skb2event(pos);
711 /* Since the entire message must be abandoned by the
712 * sender (item A3 in Section 3.5, RFC 3758), we can
713 * free all fragments on the list that are less then
714 * or equal to ctsn_point
716 if (TSN_lte(tsn, fwd_tsn)) {
717 __skb_unlink(pos, &ulpq->reasm);
718 sctp_ulpevent_free(event);
725 * Drain the reassembly queue. If we just cleared parted delivery, it
726 * is possible that the reassembly queue will contain already reassembled
727 * messages. Retrieve any such messages and give them to the user.
729 static void sctp_ulpq_reasm_drain(struct sctp_ulpq *ulpq)
731 struct sctp_ulpevent *event = NULL;
732 struct sk_buff_head temp;
734 if (skb_queue_empty(&ulpq->reasm))
737 while ((event = sctp_ulpq_retrieve_reassembled(ulpq)) != NULL) {
738 /* Do ordering if needed. */
739 if ((event) && (event->msg_flags & MSG_EOR)){
740 skb_queue_head_init(&temp);
741 __skb_queue_tail(&temp, sctp_event2skb(event));
743 event = sctp_ulpq_order(ulpq, event);
746 /* Send event to the ULP. 'event' is the
747 * sctp_ulpevent for very first SKB on the temp' list.
750 sctp_ulpq_tail_event(ulpq, event);
755 /* Helper function to gather skbs that have possibly become
756 * ordered by an an incoming chunk.
758 static void sctp_ulpq_retrieve_ordered(struct sctp_ulpq *ulpq,
759 struct sctp_ulpevent *event)
761 struct sk_buff_head *event_list;
762 struct sk_buff *pos, *tmp;
763 struct sctp_ulpevent *cevent;
764 struct sctp_stream *in;
765 __u16 sid, csid, cssn;
768 in = &ulpq->asoc->ssnmap->in;
770 event_list = (struct sk_buff_head *) sctp_event2skb(event)->prev;
772 /* We are holding the chunks by stream, by SSN. */
773 sctp_skb_for_each(pos, &ulpq->lobby, tmp) {
774 cevent = (struct sctp_ulpevent *) pos->cb;
775 csid = cevent->stream;
778 /* Have we gone too far? */
782 /* Have we not gone far enough? */
786 if (cssn != sctp_ssn_peek(in, sid))
789 /* Found it, so mark in the ssnmap. */
790 sctp_ssn_next(in, sid);
792 __skb_unlink(pos, &ulpq->lobby);
794 /* Attach all gathered skbs to the event. */
795 __skb_queue_tail(event_list, pos);
799 /* Helper function to store chunks needing ordering. */
800 static void sctp_ulpq_store_ordered(struct sctp_ulpq *ulpq,
801 struct sctp_ulpevent *event)
804 struct sctp_ulpevent *cevent;
808 pos = skb_peek_tail(&ulpq->lobby);
810 __skb_queue_tail(&ulpq->lobby, sctp_event2skb(event));
817 cevent = (struct sctp_ulpevent *) pos->cb;
818 csid = cevent->stream;
821 __skb_queue_tail(&ulpq->lobby, sctp_event2skb(event));
825 if ((sid == csid) && SSN_lt(cssn, ssn)) {
826 __skb_queue_tail(&ulpq->lobby, sctp_event2skb(event));
830 /* Find the right place in this list. We store them by
831 * stream ID and then by SSN.
833 skb_queue_walk(&ulpq->lobby, pos) {
834 cevent = (struct sctp_ulpevent *) pos->cb;
835 csid = cevent->stream;
840 if (csid == sid && SSN_lt(ssn, cssn))
845 /* Insert before pos. */
846 __skb_queue_before(&ulpq->lobby, pos, sctp_event2skb(event));
849 static struct sctp_ulpevent *sctp_ulpq_order(struct sctp_ulpq *ulpq,
850 struct sctp_ulpevent *event)
853 struct sctp_stream *in;
855 /* Check if this message needs ordering. */
856 if (SCTP_DATA_UNORDERED & event->msg_flags)
859 /* Note: The stream ID must be verified before this routine. */
862 in = &ulpq->asoc->ssnmap->in;
864 /* Is this the expected SSN for this stream ID? */
865 if (ssn != sctp_ssn_peek(in, sid)) {
866 /* We've received something out of order, so find where it
867 * needs to be placed. We order by stream and then by SSN.
869 sctp_ulpq_store_ordered(ulpq, event);
873 /* Mark that the next chunk has been found. */
874 sctp_ssn_next(in, sid);
876 /* Go find any other chunks that were waiting for
879 sctp_ulpq_retrieve_ordered(ulpq, event);
884 /* Helper function to gather skbs that have possibly become
885 * ordered by forward tsn skipping their dependencies.
887 static void sctp_ulpq_reap_ordered(struct sctp_ulpq *ulpq, __u16 sid)
889 struct sk_buff *pos, *tmp;
890 struct sctp_ulpevent *cevent;
891 struct sctp_ulpevent *event;
892 struct sctp_stream *in;
893 struct sk_buff_head temp;
894 struct sk_buff_head *lobby = &ulpq->lobby;
897 in = &ulpq->asoc->ssnmap->in;
899 /* We are holding the chunks by stream, by SSN. */
900 skb_queue_head_init(&temp);
902 sctp_skb_for_each(pos, lobby, tmp) {
903 cevent = (struct sctp_ulpevent *) pos->cb;
904 csid = cevent->stream;
907 /* Have we gone too far? */
911 /* Have we not gone far enough? */
915 /* see if this ssn has been marked by skipping */
916 if (!SSN_lt(cssn, sctp_ssn_peek(in, csid)))
919 __skb_unlink(pos, lobby);
921 /* Create a temporary list to collect chunks on. */
922 event = sctp_skb2event(pos);
924 /* Attach all gathered skbs to the event. */
925 __skb_queue_tail(&temp, pos);
928 /* If we didn't reap any data, see if the next expected SSN
929 * is next on the queue and if so, use that.
931 if (event == NULL && pos != (struct sk_buff *)lobby) {
932 cevent = (struct sctp_ulpevent *) pos->cb;
933 csid = cevent->stream;
936 if (csid == sid && cssn == sctp_ssn_peek(in, csid)) {
937 sctp_ssn_next(in, csid);
938 __skb_unlink(pos, lobby);
939 __skb_queue_tail(&temp, pos);
940 event = sctp_skb2event(pos);
944 /* Send event to the ULP. 'event' is the sctp_ulpevent for
945 * very first SKB on the 'temp' list.
948 /* see if we have more ordered that we can deliver */
949 sctp_ulpq_retrieve_ordered(ulpq, event);
950 sctp_ulpq_tail_event(ulpq, event);
954 /* Skip over an SSN. This is used during the processing of
955 * Forwared TSN chunk to skip over the abandoned ordered data
957 void sctp_ulpq_skip(struct sctp_ulpq *ulpq, __u16 sid, __u16 ssn)
959 struct sctp_stream *in;
961 /* Note: The stream ID must be verified before this routine. */
962 in = &ulpq->asoc->ssnmap->in;
964 /* Is this an old SSN? If so ignore. */
965 if (SSN_lt(ssn, sctp_ssn_peek(in, sid)))
968 /* Mark that we are no longer expecting this SSN or lower. */
969 sctp_ssn_skip(in, sid, ssn);
971 /* Go find any other chunks that were waiting for
972 * ordering and deliver them if needed.
974 sctp_ulpq_reap_ordered(ulpq, sid);
977 static __u16 sctp_ulpq_renege_list(struct sctp_ulpq *ulpq,
978 struct sk_buff_head *list, __u16 needed)
982 struct sk_buff *skb, *flist, *last;
983 struct sctp_ulpevent *event;
984 struct sctp_tsnmap *tsnmap;
986 tsnmap = &ulpq->asoc->peer.tsn_map;
988 while ((skb = skb_peek_tail(list)) != NULL) {
989 event = sctp_skb2event(skb);
992 /* Don't renege below the Cumulative TSN ACK Point. */
993 if (TSN_lte(tsn, sctp_tsnmap_get_ctsn(tsnmap)))
996 /* Events in ordering queue may have multiple fragments
997 * corresponding to additional TSNs. Sum the total
998 * freed space; find the last TSN.
1000 freed += skb_headlen(skb);
1001 flist = skb_shinfo(skb)->frag_list;
1002 for (last = flist; flist; flist = flist->next) {
1004 freed += skb_headlen(last);
1007 last_tsn = sctp_skb2event(last)->tsn;
1011 /* Unlink the event, then renege all applicable TSNs. */
1012 __skb_unlink(skb, list);
1013 sctp_ulpevent_free(event);
1014 while (TSN_lte(tsn, last_tsn)) {
1015 sctp_tsnmap_renege(tsnmap, tsn);
1018 if (freed >= needed)
1025 /* Renege 'needed' bytes from the ordering queue. */
1026 static __u16 sctp_ulpq_renege_order(struct sctp_ulpq *ulpq, __u16 needed)
1028 return sctp_ulpq_renege_list(ulpq, &ulpq->lobby, needed);
1031 /* Renege 'needed' bytes from the reassembly queue. */
1032 static __u16 sctp_ulpq_renege_frags(struct sctp_ulpq *ulpq, __u16 needed)
1034 return sctp_ulpq_renege_list(ulpq, &ulpq->reasm, needed);
1037 /* Partial deliver the first message as there is pressure on rwnd. */
1038 void sctp_ulpq_partial_delivery(struct sctp_ulpq *ulpq,
1041 struct sctp_ulpevent *event;
1042 struct sctp_association *asoc;
1043 struct sctp_sock *sp;
1045 struct sk_buff *skb;
1048 sp = sctp_sk(asoc->base.sk);
1050 /* If the association is already in Partial Delivery mode
1051 * we have nothing to do.
1056 /* Data must be at or below the Cumulative TSN ACK Point to
1057 * start partial delivery.
1059 skb = skb_peek(&asoc->ulpq.reasm);
1061 ctsn = sctp_skb2event(skb)->tsn;
1062 if (!TSN_lte(ctsn, sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map)))
1066 /* If the user enabled fragment interleave socket option,
1067 * multiple associations can enter partial delivery.
1068 * Otherwise, we can only enter partial delivery if the
1069 * socket is not in partial deliver mode.
1071 if (sp->frag_interleave || atomic_read(&sp->pd_mode) == 0) {
1072 /* Is partial delivery possible? */
1073 event = sctp_ulpq_retrieve_first(ulpq);
1074 /* Send event to the ULP. */
1076 sctp_ulpq_tail_event(ulpq, event);
1077 sctp_ulpq_set_pd(ulpq);
1083 /* Renege some packets to make room for an incoming chunk. */
1084 void sctp_ulpq_renege(struct sctp_ulpq *ulpq, struct sctp_chunk *chunk,
1087 struct sctp_association *asoc;
1088 __u16 needed, freed;
1093 needed = ntohs(chunk->chunk_hdr->length);
1094 needed -= sizeof(sctp_data_chunk_t);
1096 needed = SCTP_DEFAULT_MAXWINDOW;
1100 if (skb_queue_empty(&asoc->base.sk->sk_receive_queue)) {
1101 freed = sctp_ulpq_renege_order(ulpq, needed);
1102 if (freed < needed) {
1103 freed += sctp_ulpq_renege_frags(ulpq, needed - freed);
1106 /* If able to free enough room, accept this chunk. */
1107 if (chunk && (freed >= needed)) {
1109 retval = sctp_ulpq_tail_data(ulpq, chunk, gfp);
1111 * Enter partial delivery if chunk has not been
1112 * delivered; otherwise, drain the reassembly queue.
1115 sctp_ulpq_partial_delivery(ulpq, gfp);
1116 else if (retval == 1)
1117 sctp_ulpq_reasm_drain(ulpq);
1120 sk_mem_reclaim(asoc->base.sk);
1125 /* Notify the application if an association is aborted and in
1126 * partial delivery mode. Send up any pending received messages.
1128 void sctp_ulpq_abort_pd(struct sctp_ulpq *ulpq, gfp_t gfp)
1130 struct sctp_ulpevent *ev = NULL;
1136 sk = ulpq->asoc->base.sk;
1137 if (sctp_ulpevent_type_enabled(SCTP_PARTIAL_DELIVERY_EVENT,
1138 &sctp_sk(sk)->subscribe))
1139 ev = sctp_ulpevent_make_pdapi(ulpq->asoc,
1140 SCTP_PARTIAL_DELIVERY_ABORTED,
1143 __skb_queue_tail(&sk->sk_receive_queue, sctp_event2skb(ev));
1145 /* If there is data waiting, send it up the socket now. */
1146 if (sctp_ulpq_clear_pd(ulpq) || ev)
1147 sk->sk_data_ready(sk, 0);