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, see
25 * <http://www.gnu.org/licenses/>.
27 * Please send any bug reports or fixes you make to the
29 * lksctp developers <linux-sctp@vger.kernel.org>
31 * Written or modified by:
32 * Jon Grimm <jgrimm@us.ibm.com>
33 * La Monte H.P. Yarroll <piggy@acm.org>
34 * Sridhar Samudrala <sri@us.ibm.com>
37 #include <linux/slab.h>
38 #include <linux/types.h>
39 #include <linux/skbuff.h>
41 #include <net/busy_poll.h>
42 #include <net/sctp/structs.h>
43 #include <net/sctp/sctp.h>
44 #include <net/sctp/sm.h>
46 /* Forward declarations for internal helpers. */
47 static struct sctp_ulpevent *sctp_ulpq_reasm(struct sctp_ulpq *ulpq,
48 struct sctp_ulpevent *);
49 static struct sctp_ulpevent *sctp_ulpq_order(struct sctp_ulpq *,
50 struct sctp_ulpevent *);
51 static void sctp_ulpq_reasm_drain(struct sctp_ulpq *ulpq);
53 /* 1st Level Abstractions */
55 /* Initialize a ULP queue from a block of memory. */
56 struct sctp_ulpq *sctp_ulpq_init(struct sctp_ulpq *ulpq,
57 struct sctp_association *asoc)
59 memset(ulpq, 0, sizeof(struct sctp_ulpq));
62 skb_queue_head_init(&ulpq->reasm);
63 skb_queue_head_init(&ulpq->lobby);
70 /* Flush the reassembly and ordering queues. */
71 void sctp_ulpq_flush(struct sctp_ulpq *ulpq)
74 struct sctp_ulpevent *event;
76 while ((skb = __skb_dequeue(&ulpq->lobby)) != NULL) {
77 event = sctp_skb2event(skb);
78 sctp_ulpevent_free(event);
81 while ((skb = __skb_dequeue(&ulpq->reasm)) != NULL) {
82 event = sctp_skb2event(skb);
83 sctp_ulpevent_free(event);
88 /* Dispose of a ulpqueue. */
89 void sctp_ulpq_free(struct sctp_ulpq *ulpq)
91 sctp_ulpq_flush(ulpq);
94 /* Process an incoming DATA chunk. */
95 int sctp_ulpq_tail_data(struct sctp_ulpq *ulpq, struct sctp_chunk *chunk,
98 struct sk_buff_head temp;
99 struct sctp_ulpevent *event;
102 /* Create an event from the incoming chunk. */
103 event = sctp_ulpevent_make_rcvmsg(chunk->asoc, chunk, gfp);
107 /* Do reassembly if needed. */
108 event = sctp_ulpq_reasm(ulpq, event);
110 /* Do ordering if needed. */
111 if ((event) && (event->msg_flags & MSG_EOR)) {
112 /* Create a temporary list to collect chunks on. */
113 skb_queue_head_init(&temp);
114 __skb_queue_tail(&temp, sctp_event2skb(event));
116 event = sctp_ulpq_order(ulpq, event);
119 /* Send event to the ULP. 'event' is the sctp_ulpevent for
120 * very first SKB on the 'temp' list.
123 event_eor = (event->msg_flags & MSG_EOR) ? 1 : 0;
124 sctp_ulpq_tail_event(ulpq, event);
130 /* Add a new event for propagation to the ULP. */
131 /* Clear the partial delivery mode for this socket. Note: This
132 * assumes that no association is currently in partial delivery mode.
134 int sctp_clear_pd(struct sock *sk, struct sctp_association *asoc)
136 struct sctp_sock *sp = sctp_sk(sk);
138 if (atomic_dec_and_test(&sp->pd_mode)) {
139 /* This means there are no other associations in PD, so
140 * we can go ahead and clear out the lobby in one shot
142 if (!skb_queue_empty(&sp->pd_lobby)) {
143 struct list_head *list;
144 skb_queue_splice_tail_init(&sp->pd_lobby,
145 &sk->sk_receive_queue);
146 list = (struct list_head *)&sctp_sk(sk)->pd_lobby;
147 INIT_LIST_HEAD(list);
151 /* There are other associations in PD, so we only need to
152 * pull stuff out of the lobby that belongs to the
153 * associations that is exiting PD (all of its notifications
156 if (!skb_queue_empty(&sp->pd_lobby) && asoc) {
157 struct sk_buff *skb, *tmp;
158 struct sctp_ulpevent *event;
160 sctp_skb_for_each(skb, &sp->pd_lobby, tmp) {
161 event = sctp_skb2event(skb);
162 if (event->asoc == asoc) {
163 __skb_unlink(skb, &sp->pd_lobby);
164 __skb_queue_tail(&sk->sk_receive_queue,
174 /* Set the pd_mode on the socket and ulpq */
175 static void sctp_ulpq_set_pd(struct sctp_ulpq *ulpq)
177 struct sctp_sock *sp = sctp_sk(ulpq->asoc->base.sk);
179 atomic_inc(&sp->pd_mode);
183 /* Clear the pd_mode and restart any pending messages waiting for delivery. */
184 static int sctp_ulpq_clear_pd(struct sctp_ulpq *ulpq)
187 sctp_ulpq_reasm_drain(ulpq);
188 return sctp_clear_pd(ulpq->asoc->base.sk, ulpq->asoc);
191 /* If the SKB of 'event' is on a list, it is the first such member
194 int sctp_ulpq_tail_event(struct sctp_ulpq *ulpq, struct sctp_ulpevent *event)
196 struct sock *sk = ulpq->asoc->base.sk;
197 struct sk_buff_head *queue, *skb_list;
198 struct sk_buff *skb = sctp_event2skb(event);
201 skb_list = (struct sk_buff_head *) skb->prev;
203 /* If the socket is just going to throw this away, do not
204 * even try to deliver it.
206 if (sock_flag(sk, SOCK_DEAD) || (sk->sk_shutdown & RCV_SHUTDOWN))
209 if (!sctp_ulpevent_is_notification(event)) {
210 sk_mark_napi_id(sk, skb);
211 sk_incoming_cpu_update(sk);
213 /* Check if the user wishes to receive this event. */
214 if (!sctp_ulpevent_is_enabled(event, &sctp_sk(sk)->subscribe))
217 /* If we are in partial delivery mode, post to the lobby until
218 * partial delivery is cleared, unless, of course _this_ is
219 * the association the cause of the partial delivery.
222 if (atomic_read(&sctp_sk(sk)->pd_mode) == 0) {
223 queue = &sk->sk_receive_queue;
226 /* If the association is in partial delivery, we
227 * need to finish delivering the partially processed
228 * packet before passing any other data. This is
229 * because we don't truly support stream interleaving.
231 if ((event->msg_flags & MSG_NOTIFICATION) ||
232 (SCTP_DATA_NOT_FRAG ==
233 (event->msg_flags & SCTP_DATA_FRAG_MASK)))
234 queue = &sctp_sk(sk)->pd_lobby;
236 clear_pd = event->msg_flags & MSG_EOR;
237 queue = &sk->sk_receive_queue;
241 * If fragment interleave is enabled, we
242 * can queue this to the receive queue instead
245 if (sctp_sk(sk)->frag_interleave)
246 queue = &sk->sk_receive_queue;
248 queue = &sctp_sk(sk)->pd_lobby;
252 /* If we are harvesting multiple skbs they will be
253 * collected on a list.
256 skb_queue_splice_tail_init(skb_list, queue);
258 __skb_queue_tail(queue, skb);
260 /* Did we just complete partial delivery and need to get
261 * rolling again? Move pending data to the receive
265 sctp_ulpq_clear_pd(ulpq);
267 if (queue == &sk->sk_receive_queue)
268 sctp_sk(sk)->pending_data_ready = 1;
273 sctp_queue_purge_ulpevents(skb_list);
275 sctp_ulpevent_free(event);
280 /* 2nd Level Abstractions */
282 /* Helper function to store chunks that need to be reassembled. */
283 static void sctp_ulpq_store_reasm(struct sctp_ulpq *ulpq,
284 struct sctp_ulpevent *event)
287 struct sctp_ulpevent *cevent;
292 /* See if it belongs at the end. */
293 pos = skb_peek_tail(&ulpq->reasm);
295 __skb_queue_tail(&ulpq->reasm, sctp_event2skb(event));
299 /* Short circuit just dropping it at the end. */
300 cevent = sctp_skb2event(pos);
302 if (TSN_lt(ctsn, tsn)) {
303 __skb_queue_tail(&ulpq->reasm, sctp_event2skb(event));
307 /* Find the right place in this list. We store them by TSN. */
308 skb_queue_walk(&ulpq->reasm, pos) {
309 cevent = sctp_skb2event(pos);
312 if (TSN_lt(tsn, ctsn))
316 /* Insert before pos. */
317 __skb_queue_before(&ulpq->reasm, pos, sctp_event2skb(event));
321 /* Helper function to return an event corresponding to the reassembled
323 * This routine creates a re-assembled skb given the first and last skb's
324 * as stored in the reassembly queue. The skb's may be non-linear if the sctp
325 * payload was fragmented on the way and ip had to reassemble them.
326 * We add the rest of skb's to the first skb's fraglist.
328 static struct sctp_ulpevent *sctp_make_reassembled_event(struct net *net,
329 struct sk_buff_head *queue, struct sk_buff *f_frag,
330 struct sk_buff *l_frag)
333 struct sk_buff *new = NULL;
334 struct sctp_ulpevent *event;
335 struct sk_buff *pnext, *last;
336 struct sk_buff *list = skb_shinfo(f_frag)->frag_list;
338 /* Store the pointer to the 2nd skb */
339 if (f_frag == l_frag)
344 /* Get the last skb in the f_frag's frag_list if present. */
345 for (last = list; list; last = list, list = list->next)
348 /* Add the list of remaining fragments to the first fragments
354 if (skb_cloned(f_frag)) {
355 /* This is a cloned skb, we can't just modify
356 * the frag_list. We need a new skb to do that.
357 * Instead of calling skb_unshare(), we'll do it
358 * ourselves since we need to delay the free.
360 new = skb_copy(f_frag, GFP_ATOMIC);
362 return NULL; /* try again later */
364 sctp_skb_set_owner_r(new, f_frag->sk);
366 skb_shinfo(new)->frag_list = pos;
368 skb_shinfo(f_frag)->frag_list = pos;
371 /* Remove the first fragment from the reassembly queue. */
372 __skb_unlink(f_frag, queue);
374 /* if we did unshare, then free the old skb and re-assign */
384 /* Update the len and data_len fields of the first fragment. */
385 f_frag->len += pos->len;
386 f_frag->data_len += pos->len;
388 /* Remove the fragment from the reassembly queue. */
389 __skb_unlink(pos, queue);
391 /* Break if we have reached the last fragment. */
398 event = sctp_skb2event(f_frag);
399 SCTP_INC_STATS(net, SCTP_MIB_REASMUSRMSGS);
405 /* Helper function to check if an incoming chunk has filled up the last
406 * missing fragment in a SCTP datagram and return the corresponding event.
408 static struct sctp_ulpevent *sctp_ulpq_retrieve_reassembled(struct sctp_ulpq *ulpq)
411 struct sctp_ulpevent *cevent;
412 struct sk_buff *first_frag = NULL;
413 __u32 ctsn, next_tsn;
414 struct sctp_ulpevent *retval = NULL;
415 struct sk_buff *pd_first = NULL;
416 struct sk_buff *pd_last = NULL;
418 struct sctp_association *asoc;
421 /* Initialized to 0 just to avoid compiler warning message. Will
422 * never be used with this value. It is referenced only after it
423 * is set when we find the first fragment of a message.
427 /* The chunks are held in the reasm queue sorted by TSN.
428 * Walk through the queue sequentially and look for a sequence of
429 * fragmented chunks that complete a datagram.
430 * 'first_frag' and next_tsn are reset when we find a chunk which
431 * is the first fragment of a datagram. Once these 2 fields are set
432 * we expect to find the remaining middle fragments and the last
433 * fragment in order. If not, first_frag is reset to NULL and we
434 * start the next pass when we find another first fragment.
436 * There is a potential to do partial delivery if user sets
437 * SCTP_PARTIAL_DELIVERY_POINT option. Lets count some things here
438 * to see if can do PD.
440 skb_queue_walk(&ulpq->reasm, pos) {
441 cevent = sctp_skb2event(pos);
444 switch (cevent->msg_flags & SCTP_DATA_FRAG_MASK) {
445 case SCTP_DATA_FIRST_FRAG:
446 /* If this "FIRST_FRAG" is the first
447 * element in the queue, then count it towards
450 if (pos == ulpq->reasm.next) {
464 case SCTP_DATA_MIDDLE_FRAG:
465 if ((first_frag) && (ctsn == next_tsn)) {
475 case SCTP_DATA_LAST_FRAG:
476 if (first_frag && (ctsn == next_tsn))
486 /* Make sure we can enter partial deliver.
487 * We can trigger partial delivery only if framgent
488 * interleave is set, or the socket is not already
489 * in partial delivery.
491 if (!sctp_sk(asoc->base.sk)->frag_interleave &&
492 atomic_read(&sctp_sk(asoc->base.sk)->pd_mode))
495 cevent = sctp_skb2event(pd_first);
496 pd_point = sctp_sk(asoc->base.sk)->pd_point;
497 if (pd_point && pd_point <= pd_len) {
498 retval = sctp_make_reassembled_event(sock_net(asoc->base.sk),
503 sctp_ulpq_set_pd(ulpq);
509 retval = sctp_make_reassembled_event(sock_net(ulpq->asoc->base.sk),
510 &ulpq->reasm, first_frag, pos);
512 retval->msg_flags |= MSG_EOR;
516 /* Retrieve the next set of fragments of a partial message. */
517 static struct sctp_ulpevent *sctp_ulpq_retrieve_partial(struct sctp_ulpq *ulpq)
519 struct sk_buff *pos, *last_frag, *first_frag;
520 struct sctp_ulpevent *cevent;
521 __u32 ctsn, next_tsn;
523 struct sctp_ulpevent *retval;
525 /* The chunks are held in the reasm queue sorted by TSN.
526 * Walk through the queue sequentially and look for the first
527 * sequence of fragmented chunks.
530 if (skb_queue_empty(&ulpq->reasm))
533 last_frag = first_frag = NULL;
538 skb_queue_walk(&ulpq->reasm, pos) {
539 cevent = sctp_skb2event(pos);
542 switch (cevent->msg_flags & SCTP_DATA_FRAG_MASK) {
543 case SCTP_DATA_FIRST_FRAG:
547 case SCTP_DATA_MIDDLE_FRAG:
552 } else if (next_tsn == ctsn) {
558 case SCTP_DATA_LAST_FRAG:
561 else if (ctsn != next_tsn)
571 /* We have the reassembled event. There is no need to look
575 retval = sctp_make_reassembled_event(sock_net(ulpq->asoc->base.sk),
576 &ulpq->reasm, first_frag, last_frag);
577 if (retval && is_last)
578 retval->msg_flags |= MSG_EOR;
584 /* Helper function to reassemble chunks. Hold chunks on the reasm queue that
587 static struct sctp_ulpevent *sctp_ulpq_reasm(struct sctp_ulpq *ulpq,
588 struct sctp_ulpevent *event)
590 struct sctp_ulpevent *retval = NULL;
592 /* Check if this is part of a fragmented message. */
593 if (SCTP_DATA_NOT_FRAG == (event->msg_flags & SCTP_DATA_FRAG_MASK)) {
594 event->msg_flags |= MSG_EOR;
598 sctp_ulpq_store_reasm(ulpq, event);
600 retval = sctp_ulpq_retrieve_reassembled(ulpq);
604 /* Do not even bother unless this is the next tsn to
608 ctsnap = sctp_tsnmap_get_ctsn(&ulpq->asoc->peer.tsn_map);
609 if (TSN_lte(ctsn, ctsnap))
610 retval = sctp_ulpq_retrieve_partial(ulpq);
616 /* Retrieve the first part (sequential fragments) for partial delivery. */
617 static struct sctp_ulpevent *sctp_ulpq_retrieve_first(struct sctp_ulpq *ulpq)
619 struct sk_buff *pos, *last_frag, *first_frag;
620 struct sctp_ulpevent *cevent;
621 __u32 ctsn, next_tsn;
622 struct sctp_ulpevent *retval;
624 /* The chunks are held in the reasm queue sorted by TSN.
625 * Walk through the queue sequentially and look for a sequence of
626 * fragmented chunks that start a datagram.
629 if (skb_queue_empty(&ulpq->reasm))
632 last_frag = first_frag = NULL;
636 skb_queue_walk(&ulpq->reasm, pos) {
637 cevent = sctp_skb2event(pos);
640 switch (cevent->msg_flags & SCTP_DATA_FRAG_MASK) {
641 case SCTP_DATA_FIRST_FRAG:
650 case SCTP_DATA_MIDDLE_FRAG:
653 if (ctsn == next_tsn) {
660 case SCTP_DATA_LAST_FRAG:
672 /* We have the reassembled event. There is no need to look
676 retval = sctp_make_reassembled_event(sock_net(ulpq->asoc->base.sk),
677 &ulpq->reasm, first_frag, last_frag);
682 * Flush out stale fragments from the reassembly queue when processing
685 * RFC 3758, Section 3.6
687 * After receiving and processing a FORWARD TSN, the data receiver MUST
688 * take cautions in updating its re-assembly queue. The receiver MUST
689 * remove any partially reassembled message, which is still missing one
690 * or more TSNs earlier than or equal to the new cumulative TSN point.
691 * In the event that the receiver has invoked the partial delivery API,
692 * a notification SHOULD also be generated to inform the upper layer API
693 * that the message being partially delivered will NOT be completed.
695 void sctp_ulpq_reasm_flushtsn(struct sctp_ulpq *ulpq, __u32 fwd_tsn)
697 struct sk_buff *pos, *tmp;
698 struct sctp_ulpevent *event;
701 if (skb_queue_empty(&ulpq->reasm))
704 skb_queue_walk_safe(&ulpq->reasm, pos, tmp) {
705 event = sctp_skb2event(pos);
708 /* Since the entire message must be abandoned by the
709 * sender (item A3 in Section 3.5, RFC 3758), we can
710 * free all fragments on the list that are less then
711 * or equal to ctsn_point
713 if (TSN_lte(tsn, fwd_tsn)) {
714 __skb_unlink(pos, &ulpq->reasm);
715 sctp_ulpevent_free(event);
722 * Drain the reassembly queue. If we just cleared parted delivery, it
723 * is possible that the reassembly queue will contain already reassembled
724 * messages. Retrieve any such messages and give them to the user.
726 static void sctp_ulpq_reasm_drain(struct sctp_ulpq *ulpq)
728 struct sctp_ulpevent *event = NULL;
729 struct sk_buff_head temp;
731 if (skb_queue_empty(&ulpq->reasm))
734 while ((event = sctp_ulpq_retrieve_reassembled(ulpq)) != NULL) {
735 /* Do ordering if needed. */
736 if ((event) && (event->msg_flags & MSG_EOR)) {
737 skb_queue_head_init(&temp);
738 __skb_queue_tail(&temp, sctp_event2skb(event));
740 event = sctp_ulpq_order(ulpq, event);
743 /* Send event to the ULP. 'event' is the
744 * sctp_ulpevent for very first SKB on the temp' list.
747 sctp_ulpq_tail_event(ulpq, event);
752 /* Helper function to gather skbs that have possibly become
753 * ordered by an an incoming chunk.
755 static void sctp_ulpq_retrieve_ordered(struct sctp_ulpq *ulpq,
756 struct sctp_ulpevent *event)
758 struct sk_buff_head *event_list;
759 struct sk_buff *pos, *tmp;
760 struct sctp_ulpevent *cevent;
761 struct sctp_stream *in;
762 __u16 sid, csid, cssn;
765 in = &ulpq->asoc->ssnmap->in;
767 event_list = (struct sk_buff_head *) sctp_event2skb(event)->prev;
769 /* We are holding the chunks by stream, by SSN. */
770 sctp_skb_for_each(pos, &ulpq->lobby, tmp) {
771 cevent = (struct sctp_ulpevent *) pos->cb;
772 csid = cevent->stream;
775 /* Have we gone too far? */
779 /* Have we not gone far enough? */
783 if (cssn != sctp_ssn_peek(in, sid))
786 /* Found it, so mark in the ssnmap. */
787 sctp_ssn_next(in, sid);
789 __skb_unlink(pos, &ulpq->lobby);
791 /* Attach all gathered skbs to the event. */
792 __skb_queue_tail(event_list, pos);
796 /* Helper function to store chunks needing ordering. */
797 static void sctp_ulpq_store_ordered(struct sctp_ulpq *ulpq,
798 struct sctp_ulpevent *event)
801 struct sctp_ulpevent *cevent;
805 pos = skb_peek_tail(&ulpq->lobby);
807 __skb_queue_tail(&ulpq->lobby, sctp_event2skb(event));
814 cevent = (struct sctp_ulpevent *) pos->cb;
815 csid = cevent->stream;
818 __skb_queue_tail(&ulpq->lobby, sctp_event2skb(event));
822 if ((sid == csid) && SSN_lt(cssn, ssn)) {
823 __skb_queue_tail(&ulpq->lobby, sctp_event2skb(event));
827 /* Find the right place in this list. We store them by
828 * stream ID and then by SSN.
830 skb_queue_walk(&ulpq->lobby, pos) {
831 cevent = (struct sctp_ulpevent *) pos->cb;
832 csid = cevent->stream;
837 if (csid == sid && SSN_lt(ssn, cssn))
842 /* Insert before pos. */
843 __skb_queue_before(&ulpq->lobby, pos, sctp_event2skb(event));
846 static struct sctp_ulpevent *sctp_ulpq_order(struct sctp_ulpq *ulpq,
847 struct sctp_ulpevent *event)
850 struct sctp_stream *in;
852 /* Check if this message needs ordering. */
853 if (SCTP_DATA_UNORDERED & event->msg_flags)
856 /* Note: The stream ID must be verified before this routine. */
859 in = &ulpq->asoc->ssnmap->in;
861 /* Is this the expected SSN for this stream ID? */
862 if (ssn != sctp_ssn_peek(in, sid)) {
863 /* We've received something out of order, so find where it
864 * needs to be placed. We order by stream and then by SSN.
866 sctp_ulpq_store_ordered(ulpq, event);
870 /* Mark that the next chunk has been found. */
871 sctp_ssn_next(in, sid);
873 /* Go find any other chunks that were waiting for
876 sctp_ulpq_retrieve_ordered(ulpq, event);
881 /* Helper function to gather skbs that have possibly become
882 * ordered by forward tsn skipping their dependencies.
884 static void sctp_ulpq_reap_ordered(struct sctp_ulpq *ulpq, __u16 sid)
886 struct sk_buff *pos, *tmp;
887 struct sctp_ulpevent *cevent;
888 struct sctp_ulpevent *event;
889 struct sctp_stream *in;
890 struct sk_buff_head temp;
891 struct sk_buff_head *lobby = &ulpq->lobby;
894 in = &ulpq->asoc->ssnmap->in;
896 /* We are holding the chunks by stream, by SSN. */
897 skb_queue_head_init(&temp);
899 sctp_skb_for_each(pos, lobby, tmp) {
900 cevent = (struct sctp_ulpevent *) pos->cb;
901 csid = cevent->stream;
904 /* Have we gone too far? */
908 /* Have we not gone far enough? */
912 /* see if this ssn has been marked by skipping */
913 if (!SSN_lt(cssn, sctp_ssn_peek(in, csid)))
916 __skb_unlink(pos, lobby);
918 /* Create a temporary list to collect chunks on. */
919 event = sctp_skb2event(pos);
921 /* Attach all gathered skbs to the event. */
922 __skb_queue_tail(&temp, pos);
925 /* If we didn't reap any data, see if the next expected SSN
926 * is next on the queue and if so, use that.
928 if (event == NULL && pos != (struct sk_buff *)lobby) {
929 cevent = (struct sctp_ulpevent *) pos->cb;
930 csid = cevent->stream;
933 if (csid == sid && cssn == sctp_ssn_peek(in, csid)) {
934 sctp_ssn_next(in, csid);
935 __skb_unlink(pos, lobby);
936 __skb_queue_tail(&temp, pos);
937 event = sctp_skb2event(pos);
941 /* Send event to the ULP. 'event' is the sctp_ulpevent for
942 * very first SKB on the 'temp' list.
945 /* see if we have more ordered that we can deliver */
946 sctp_ulpq_retrieve_ordered(ulpq, event);
947 sctp_ulpq_tail_event(ulpq, event);
951 /* Skip over an SSN. This is used during the processing of
952 * Forwared TSN chunk to skip over the abandoned ordered data
954 void sctp_ulpq_skip(struct sctp_ulpq *ulpq, __u16 sid, __u16 ssn)
956 struct sctp_stream *in;
958 /* Note: The stream ID must be verified before this routine. */
959 in = &ulpq->asoc->ssnmap->in;
961 /* Is this an old SSN? If so ignore. */
962 if (SSN_lt(ssn, sctp_ssn_peek(in, sid)))
965 /* Mark that we are no longer expecting this SSN or lower. */
966 sctp_ssn_skip(in, sid, ssn);
968 /* Go find any other chunks that were waiting for
969 * ordering and deliver them if needed.
971 sctp_ulpq_reap_ordered(ulpq, sid);
974 static __u16 sctp_ulpq_renege_list(struct sctp_ulpq *ulpq,
975 struct sk_buff_head *list, __u16 needed)
979 struct sk_buff *skb, *flist, *last;
980 struct sctp_ulpevent *event;
981 struct sctp_tsnmap *tsnmap;
983 tsnmap = &ulpq->asoc->peer.tsn_map;
985 while ((skb = skb_peek_tail(list)) != NULL) {
986 event = sctp_skb2event(skb);
989 /* Don't renege below the Cumulative TSN ACK Point. */
990 if (TSN_lte(tsn, sctp_tsnmap_get_ctsn(tsnmap)))
993 /* Events in ordering queue may have multiple fragments
994 * corresponding to additional TSNs. Sum the total
995 * freed space; find the last TSN.
997 freed += skb_headlen(skb);
998 flist = skb_shinfo(skb)->frag_list;
999 for (last = flist; flist; flist = flist->next) {
1001 freed += skb_headlen(last);
1004 last_tsn = sctp_skb2event(last)->tsn;
1008 /* Unlink the event, then renege all applicable TSNs. */
1009 __skb_unlink(skb, list);
1010 sctp_ulpevent_free(event);
1011 while (TSN_lte(tsn, last_tsn)) {
1012 sctp_tsnmap_renege(tsnmap, tsn);
1015 if (freed >= needed)
1022 /* Renege 'needed' bytes from the ordering queue. */
1023 static __u16 sctp_ulpq_renege_order(struct sctp_ulpq *ulpq, __u16 needed)
1025 return sctp_ulpq_renege_list(ulpq, &ulpq->lobby, needed);
1028 /* Renege 'needed' bytes from the reassembly queue. */
1029 static __u16 sctp_ulpq_renege_frags(struct sctp_ulpq *ulpq, __u16 needed)
1031 return sctp_ulpq_renege_list(ulpq, &ulpq->reasm, needed);
1034 /* Partial deliver the first message as there is pressure on rwnd. */
1035 void sctp_ulpq_partial_delivery(struct sctp_ulpq *ulpq,
1038 struct sctp_ulpevent *event;
1039 struct sctp_association *asoc;
1040 struct sctp_sock *sp;
1042 struct sk_buff *skb;
1045 sp = sctp_sk(asoc->base.sk);
1047 /* If the association is already in Partial Delivery mode
1048 * we have nothing to do.
1053 /* Data must be at or below the Cumulative TSN ACK Point to
1054 * start partial delivery.
1056 skb = skb_peek(&asoc->ulpq.reasm);
1058 ctsn = sctp_skb2event(skb)->tsn;
1059 if (!TSN_lte(ctsn, sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map)))
1063 /* If the user enabled fragment interleave socket option,
1064 * multiple associations can enter partial delivery.
1065 * Otherwise, we can only enter partial delivery if the
1066 * socket is not in partial deliver mode.
1068 if (sp->frag_interleave || atomic_read(&sp->pd_mode) == 0) {
1069 /* Is partial delivery possible? */
1070 event = sctp_ulpq_retrieve_first(ulpq);
1071 /* Send event to the ULP. */
1073 sctp_ulpq_tail_event(ulpq, event);
1074 sctp_ulpq_set_pd(ulpq);
1080 /* Renege some packets to make room for an incoming chunk. */
1081 void sctp_ulpq_renege(struct sctp_ulpq *ulpq, struct sctp_chunk *chunk,
1084 struct sctp_association *asoc;
1085 __u16 needed, freed;
1090 needed = ntohs(chunk->chunk_hdr->length);
1091 needed -= sizeof(sctp_data_chunk_t);
1093 needed = SCTP_DEFAULT_MAXWINDOW;
1097 if (skb_queue_empty(&asoc->base.sk->sk_receive_queue)) {
1098 freed = sctp_ulpq_renege_order(ulpq, needed);
1099 if (freed < needed) {
1100 freed += sctp_ulpq_renege_frags(ulpq, needed - freed);
1103 /* If able to free enough room, accept this chunk. */
1104 if (chunk && (freed >= needed)) {
1106 retval = sctp_ulpq_tail_data(ulpq, chunk, gfp);
1108 * Enter partial delivery if chunk has not been
1109 * delivered; otherwise, drain the reassembly queue.
1112 sctp_ulpq_partial_delivery(ulpq, gfp);
1113 else if (retval == 1)
1114 sctp_ulpq_reasm_drain(ulpq);
1117 sk_mem_reclaim(asoc->base.sk);
1122 /* Notify the application if an association is aborted and in
1123 * partial delivery mode. Send up any pending received messages.
1125 void sctp_ulpq_abort_pd(struct sctp_ulpq *ulpq, gfp_t gfp)
1127 struct sctp_ulpevent *ev = NULL;
1133 sk = ulpq->asoc->base.sk;
1134 if (sctp_ulpevent_type_enabled(SCTP_PARTIAL_DELIVERY_EVENT,
1135 &sctp_sk(sk)->subscribe))
1136 ev = sctp_ulpevent_make_pdapi(ulpq->asoc,
1137 SCTP_PARTIAL_DELIVERY_ABORTED,
1140 __skb_queue_tail(&sk->sk_receive_queue, sctp_event2skb(ev));
1142 /* If there is data waiting, send it up the socket now. */
1143 if (sctp_ulpq_clear_pd(ulpq) || ev)
1144 sctp_sk(sk)->pending_data_ready = 1;