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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
8 *
9 * This abstraction carries sctp events to the ULP (sockets).
10 *
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)
15 * any later version.
16 *
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.
22 *
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.
27 *
28 * Please send any bug reports or fixes you make to the
29 * email address(es):
30 * lksctp developers <lksctp-developers@lists.sourceforge.net>
31 *
32 * Or submit a bug report through the following website:
33 * http://www.sf.net/projects/lksctp
34 *
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>
39 *
40 * Any bugs reported given to us we will try to fix... any fixes shared will
41 * be incorporated into the next SCTP release.
42 */
43
44#include <linux/slab.h>
45#include <linux/types.h>
46#include <linux/skbuff.h>
47#include <net/sock.h>
48#include <net/sctp/structs.h>
49#include <net/sctp/sctp.h>
50#include <net/sctp/sm.h>
51
52/* Forward declarations for internal helpers. */
53static struct sctp_ulpevent * sctp_ulpq_reasm(struct sctp_ulpq *ulpq,
54 struct sctp_ulpevent *);
55static struct sctp_ulpevent * sctp_ulpq_order(struct sctp_ulpq *,
56 struct sctp_ulpevent *);
57static void sctp_ulpq_reasm_drain(struct sctp_ulpq *ulpq);
58
59/* 1st Level Abstractions */
60
61/* Initialize a ULP queue from a block of memory. */
62struct sctp_ulpq *sctp_ulpq_init(struct sctp_ulpq *ulpq,
63 struct sctp_association *asoc)
64{
65 memset(ulpq, 0, sizeof(struct sctp_ulpq));
66
67 ulpq->asoc = asoc;
68 skb_queue_head_init(&ulpq->reasm);
69 skb_queue_head_init(&ulpq->lobby);
70 ulpq->pd_mode = 0;
71 ulpq->malloced = 0;
72
73 return ulpq;
74}
75
76
77/* Flush the reassembly and ordering queues. */
78void sctp_ulpq_flush(struct sctp_ulpq *ulpq)
79{
80 struct sk_buff *skb;
81 struct sctp_ulpevent *event;
82
83 while ((skb = __skb_dequeue(&ulpq->lobby)) != NULL) {
84 event = sctp_skb2event(skb);
85 sctp_ulpevent_free(event);
86 }
87
88 while ((skb = __skb_dequeue(&ulpq->reasm)) != NULL) {
89 event = sctp_skb2event(skb);
90 sctp_ulpevent_free(event);
91 }
92
93}
94
95/* Dispose of a ulpqueue. */
96void sctp_ulpq_free(struct sctp_ulpq *ulpq)
97{
98 sctp_ulpq_flush(ulpq);
99 if (ulpq->malloced)
100 kfree(ulpq);
101}
102
103/* Process an incoming DATA chunk. */
104int sctp_ulpq_tail_data(struct sctp_ulpq *ulpq, struct sctp_chunk *chunk,
105 gfp_t gfp)
106{
107 struct sk_buff_head temp;
108 struct sctp_ulpevent *event;
109
110 /* Create an event from the incoming chunk. */
111 event = sctp_ulpevent_make_rcvmsg(chunk->asoc, chunk, gfp);
112 if (!event)
113 return -ENOMEM;
114
115 /* Do reassembly if needed. */
116 event = sctp_ulpq_reasm(ulpq, event);
117
118 /* Do ordering if needed. */
119 if ((event) && (event->msg_flags & MSG_EOR)){
120 /* Create a temporary list to collect chunks on. */
121 skb_queue_head_init(&temp);
122 __skb_queue_tail(&temp, sctp_event2skb(event));
123
124 event = sctp_ulpq_order(ulpq, event);
125 }
126
127 /* Send event to the ULP. 'event' is the sctp_ulpevent for
128 * very first SKB on the 'temp' list.
129 */
130 if (event)
131 sctp_ulpq_tail_event(ulpq, event);
132
133 return 0;
134}
135
136/* Add a new event for propagation to the ULP. */
137/* Clear the partial delivery mode for this socket. Note: This
138 * assumes that no association is currently in partial delivery mode.
139 */
140int sctp_clear_pd(struct sock *sk, struct sctp_association *asoc)
141{
142 struct sctp_sock *sp = sctp_sk(sk);
143
144 if (atomic_dec_and_test(&sp->pd_mode)) {
145 /* This means there are no other associations in PD, so
146 * we can go ahead and clear out the lobby in one shot
147 */
148 if (!skb_queue_empty(&sp->pd_lobby)) {
149 struct list_head *list;
150 sctp_skb_list_tail(&sp->pd_lobby, &sk->sk_receive_queue);
151 list = (struct list_head *)&sctp_sk(sk)->pd_lobby;
152 INIT_LIST_HEAD(list);
153 return 1;
154 }
155 } else {
156 /* There are other associations in PD, so we only need to
157 * pull stuff out of the lobby that belongs to the
158 * associations that is exiting PD (all of its notifications
159 * are posted here).
160 */
161 if (!skb_queue_empty(&sp->pd_lobby) && asoc) {
162 struct sk_buff *skb, *tmp;
163 struct sctp_ulpevent *event;
164
165 sctp_skb_for_each(skb, &sp->pd_lobby, tmp) {
166 event = sctp_skb2event(skb);
167 if (event->asoc == asoc) {
168 __skb_unlink(skb, &sp->pd_lobby);
169 __skb_queue_tail(&sk->sk_receive_queue,
170 skb);
171 }
172 }
173 }
174 }
175
176 return 0;
177}
178
179/* Set the pd_mode on the socket and ulpq */
180static void sctp_ulpq_set_pd(struct sctp_ulpq *ulpq)
181{
182 struct sctp_sock *sp = sctp_sk(ulpq->asoc->base.sk);
183
184 atomic_inc(&sp->pd_mode);
185 ulpq->pd_mode = 1;
186}
187
188/* Clear the pd_mode and restart any pending messages waiting for delivery. */
189static int sctp_ulpq_clear_pd(struct sctp_ulpq *ulpq)
190{
191 ulpq->pd_mode = 0;
192 sctp_ulpq_reasm_drain(ulpq);
193 return sctp_clear_pd(ulpq->asoc->base.sk, ulpq->asoc);
194}
195
196/* If the SKB of 'event' is on a list, it is the first such member
197 * of that list.
198 */
199int sctp_ulpq_tail_event(struct sctp_ulpq *ulpq, struct sctp_ulpevent *event)
200{
201 struct sock *sk = ulpq->asoc->base.sk;
202 struct sk_buff_head *queue, *skb_list;
203 struct sk_buff *skb = sctp_event2skb(event);
204 int clear_pd = 0;
205
206 skb_list = (struct sk_buff_head *) skb->prev;
207
208 /* If the socket is just going to throw this away, do not
209 * even try to deliver it.
210 */
211 if (sock_flag(sk, SOCK_DEAD) || (sk->sk_shutdown & RCV_SHUTDOWN))
212 goto out_free;
213
214 /* Check if the user wishes to receive this event. */
215 if (!sctp_ulpevent_is_enabled(event, &sctp_sk(sk)->subscribe))
216 goto out_free;
217
218 /* If we are in partial delivery mode, post to the lobby until
219 * partial delivery is cleared, unless, of course _this_ is
220 * the association the cause of the partial delivery.
221 */
222
223 if (atomic_read(&sctp_sk(sk)->pd_mode) == 0) {
224 queue = &sk->sk_receive_queue;
225 } else {
226 if (ulpq->pd_mode) {
227 /* If the association is in partial delivery, we
228 * need to finish delivering the partially processed
229 * packet before passing any other data. This is
230 * because we don't truly support stream interleaving.
231 */
232 if ((event->msg_flags & MSG_NOTIFICATION) ||
233 (SCTP_DATA_NOT_FRAG ==
234 (event->msg_flags & SCTP_DATA_FRAG_MASK)))
235 queue = &sctp_sk(sk)->pd_lobby;
236 else {
237 clear_pd = event->msg_flags & MSG_EOR;
238 queue = &sk->sk_receive_queue;
239 }
240 } else {
241 /*
242 * If fragment interleave is enabled, we
243 * can queue this to the receive queue instead
244 * of the lobby.
245 */
246 if (sctp_sk(sk)->frag_interleave)
247 queue = &sk->sk_receive_queue;
248 else
249 queue = &sctp_sk(sk)->pd_lobby;
250 }
251 }
252
253 /* If we are harvesting multiple skbs they will be
254 * collected on a list.
255 */
256 if (skb_list)
257 sctp_skb_list_tail(skb_list, queue);
258 else
259 __skb_queue_tail(queue, skb);
260
261 /* Did we just complete partial delivery and need to get
262 * rolling again? Move pending data to the receive
263 * queue.
264 */
265 if (clear_pd)
266 sctp_ulpq_clear_pd(ulpq);
267
268 if (queue == &sk->sk_receive_queue)
269 sk->sk_data_ready(sk, 0);
270 return 1;
271
272out_free:
273 if (skb_list)
274 sctp_queue_purge_ulpevents(skb_list);
275 else
276 sctp_ulpevent_free(event);
277
278 return 0;
279}
280
281/* 2nd Level Abstractions */
282
283/* Helper function to store chunks that need to be reassembled. */
284static void sctp_ulpq_store_reasm(struct sctp_ulpq *ulpq,
285 struct sctp_ulpevent *event)
286{
287 struct sk_buff *pos;
288 struct sctp_ulpevent *cevent;
289 __u32 tsn, ctsn;
290
291 tsn = event->tsn;
292
293 /* See if it belongs at the end. */
294 pos = skb_peek_tail(&ulpq->reasm);
295 if (!pos) {
296 __skb_queue_tail(&ulpq->reasm, sctp_event2skb(event));
297 return;
298 }
299
300 /* Short circuit just dropping it at the end. */
301 cevent = sctp_skb2event(pos);
302 ctsn = cevent->tsn;
303 if (TSN_lt(ctsn, tsn)) {
304 __skb_queue_tail(&ulpq->reasm, sctp_event2skb(event));
305 return;
306 }
307
308 /* Find the right place in this list. We store them by TSN. */
309 skb_queue_walk(&ulpq->reasm, pos) {
310 cevent = sctp_skb2event(pos);
311 ctsn = cevent->tsn;
312
313 if (TSN_lt(tsn, ctsn))
314 break;
315 }
316
317 /* Insert before pos. */
318 __skb_queue_before(&ulpq->reasm, pos, sctp_event2skb(event));
319
320}
321
322/* Helper function to return an event corresponding to the reassembled
323 * datagram.
324 * This routine creates a re-assembled skb given the first and last skb's
325 * as stored in the reassembly queue. The skb's may be non-linear if the sctp
326 * payload was fragmented on the way and ip had to reassemble them.
327 * We add the rest of skb's to the first skb's fraglist.
328 */
329static struct sctp_ulpevent *sctp_make_reassembled_event(struct sk_buff_head *queue, struct sk_buff *f_frag, struct sk_buff *l_frag)
330{
331 struct sk_buff *pos;
332 struct sk_buff *new = NULL;
333 struct sctp_ulpevent *event;
334 struct sk_buff *pnext, *last;
335 struct sk_buff *list = skb_shinfo(f_frag)->frag_list;
336
337 /* Store the pointer to the 2nd skb */
338 if (f_frag == l_frag)
339 pos = NULL;
340 else
341 pos = f_frag->next;
342
343 /* Get the last skb in the f_frag's frag_list if present. */
344 for (last = list; list; last = list, list = list->next);
345
346 /* Add the list of remaining fragments to the first fragments
347 * frag_list.
348 */
349 if (last)
350 last->next = pos;
351 else {
352 if (skb_cloned(f_frag)) {
353 /* This is a cloned skb, we can't just modify
354 * the frag_list. We need a new skb to do that.
355 * Instead of calling skb_unshare(), we'll do it
356 * ourselves since we need to delay the free.
357 */
358 new = skb_copy(f_frag, GFP_ATOMIC);
359 if (!new)
360 return NULL; /* try again later */
361
362 sctp_skb_set_owner_r(new, f_frag->sk);
363
364 skb_shinfo(new)->frag_list = pos;
365 } else
366 skb_shinfo(f_frag)->frag_list = pos;
367 }
368
369 /* Remove the first fragment from the reassembly queue. */
370 __skb_unlink(f_frag, queue);
371
372 /* if we did unshare, then free the old skb and re-assign */
373 if (new) {
374 kfree_skb(f_frag);
375 f_frag = new;
376 }
377
378 while (pos) {
379
380 pnext = pos->next;
381
382 /* Update the len and data_len fields of the first fragment. */
383 f_frag->len += pos->len;
384 f_frag->data_len += pos->len;
385
386 /* Remove the fragment from the reassembly queue. */
387 __skb_unlink(pos, queue);
388
389 /* Break if we have reached the last fragment. */
390 if (pos == l_frag)
391 break;
392 pos->next = pnext;
393 pos = pnext;
394 }
395
396 event = sctp_skb2event(f_frag);
397 SCTP_INC_STATS(SCTP_MIB_REASMUSRMSGS);
398
399 return event;
400}
401
402
403/* Helper function to check if an incoming chunk has filled up the last
404 * missing fragment in a SCTP datagram and return the corresponding event.
405 */
406static struct sctp_ulpevent *sctp_ulpq_retrieve_reassembled(struct sctp_ulpq *ulpq)
407{
408 struct sk_buff *pos;
409 struct sctp_ulpevent *cevent;
410 struct sk_buff *first_frag = NULL;
411 __u32 ctsn, next_tsn;
412 struct sctp_ulpevent *retval = NULL;
413 struct sk_buff *pd_first = NULL;
414 struct sk_buff *pd_last = NULL;
415 size_t pd_len = 0;
416 struct sctp_association *asoc;
417 u32 pd_point;
418
419 /* Initialized to 0 just to avoid compiler warning message. Will
420 * never be used with this value. It is referenced only after it
421 * is set when we find the first fragment of a message.
422 */
423 next_tsn = 0;
424
425 /* The chunks are held in the reasm queue sorted by TSN.
426 * Walk through the queue sequentially and look for a sequence of
427 * fragmented chunks that complete a datagram.
428 * 'first_frag' and next_tsn are reset when we find a chunk which
429 * is the first fragment of a datagram. Once these 2 fields are set
430 * we expect to find the remaining middle fragments and the last
431 * fragment in order. If not, first_frag is reset to NULL and we
432 * start the next pass when we find another first fragment.
433 *
434 * There is a potential to do partial delivery if user sets
435 * SCTP_PARTIAL_DELIVERY_POINT option. Lets count some things here
436 * to see if can do PD.
437 */
438 skb_queue_walk(&ulpq->reasm, pos) {
439 cevent = sctp_skb2event(pos);
440 ctsn = cevent->tsn;
441
442 switch (cevent->msg_flags & SCTP_DATA_FRAG_MASK) {
443 case SCTP_DATA_FIRST_FRAG:
444 /* If this "FIRST_FRAG" is the first
445 * element in the queue, then count it towards
446 * possible PD.
447 */
448 if (pos == ulpq->reasm.next) {
449 pd_first = pos;
450 pd_last = pos;
451 pd_len = pos->len;
452 } else {
453 pd_first = NULL;
454 pd_last = NULL;
455 pd_len = 0;
456 }
457
458 first_frag = pos;
459 next_tsn = ctsn + 1;
460 break;
461
462 case SCTP_DATA_MIDDLE_FRAG:
463 if ((first_frag) && (ctsn == next_tsn)) {
464 next_tsn++;
465 if (pd_first) {
466 pd_last = pos;
467 pd_len += pos->len;
468 }
469 } else
470 first_frag = NULL;
471 break;
472
473 case SCTP_DATA_LAST_FRAG:
474 if (first_frag && (ctsn == next_tsn))
475 goto found;
476 else
477 first_frag = NULL;
478 break;
479 }
480 }
481
482 asoc = ulpq->asoc;
483 if (pd_first) {
484 /* Make sure we can enter partial deliver.
485 * We can trigger partial delivery only if framgent
486 * interleave is set, or the socket is not already
487 * in partial delivery.
488 */
489 if (!sctp_sk(asoc->base.sk)->frag_interleave &&
490 atomic_read(&sctp_sk(asoc->base.sk)->pd_mode))
491 goto done;
492
493 cevent = sctp_skb2event(pd_first);
494 pd_point = sctp_sk(asoc->base.sk)->pd_point;
495 if (pd_point && pd_point <= pd_len) {
496 retval = sctp_make_reassembled_event(&ulpq->reasm,
497 pd_first,
498 pd_last);
499 if (retval)
500 sctp_ulpq_set_pd(ulpq);
501 }
502 }
503done:
504 return retval;
505found:
506 retval = sctp_make_reassembled_event(&ulpq->reasm, first_frag, pos);
507 if (retval)
508 retval->msg_flags |= MSG_EOR;
509 goto done;
510}
511
512/* Retrieve the next set of fragments of a partial message. */
513static struct sctp_ulpevent *sctp_ulpq_retrieve_partial(struct sctp_ulpq *ulpq)
514{
515 struct sk_buff *pos, *last_frag, *first_frag;
516 struct sctp_ulpevent *cevent;
517 __u32 ctsn, next_tsn;
518 int is_last;
519 struct sctp_ulpevent *retval;
520
521 /* The chunks are held in the reasm queue sorted by TSN.
522 * Walk through the queue sequentially and look for the first
523 * sequence of fragmented chunks.
524 */
525
526 if (skb_queue_empty(&ulpq->reasm))
527 return NULL;
528
529 last_frag = first_frag = NULL;
530 retval = NULL;
531 next_tsn = 0;
532 is_last = 0;
533
534 skb_queue_walk(&ulpq->reasm, pos) {
535 cevent = sctp_skb2event(pos);
536 ctsn = cevent->tsn;
537
538 switch (cevent->msg_flags & SCTP_DATA_FRAG_MASK) {
539 case SCTP_DATA_MIDDLE_FRAG:
540 if (!first_frag) {
541 first_frag = pos;
542 next_tsn = ctsn + 1;
543 last_frag = pos;
544 } else if (next_tsn == ctsn)
545 next_tsn++;
546 else
547 goto done;
548 break;
549 case SCTP_DATA_LAST_FRAG:
550 if (!first_frag)
551 first_frag = pos;
552 else if (ctsn != next_tsn)
553 goto done;
554 last_frag = pos;
555 is_last = 1;
556 goto done;
557 default:
558 return NULL;
559 }
560 }
561
562 /* We have the reassembled event. There is no need to look
563 * further.
564 */
565done:
566 retval = sctp_make_reassembled_event(&ulpq->reasm, first_frag, last_frag);
567 if (retval && is_last)
568 retval->msg_flags |= MSG_EOR;
569
570 return retval;
571}
572
573
574/* Helper function to reassemble chunks. Hold chunks on the reasm queue that
575 * need reassembling.
576 */
577static struct sctp_ulpevent *sctp_ulpq_reasm(struct sctp_ulpq *ulpq,
578 struct sctp_ulpevent *event)
579{
580 struct sctp_ulpevent *retval = NULL;
581
582 /* Check if this is part of a fragmented message. */
583 if (SCTP_DATA_NOT_FRAG == (event->msg_flags & SCTP_DATA_FRAG_MASK)) {
584 event->msg_flags |= MSG_EOR;
585 return event;
586 }
587
588 sctp_ulpq_store_reasm(ulpq, event);
589 if (!ulpq->pd_mode)
590 retval = sctp_ulpq_retrieve_reassembled(ulpq);
591 else {
592 __u32 ctsn, ctsnap;
593
594 /* Do not even bother unless this is the next tsn to
595 * be delivered.
596 */
597 ctsn = event->tsn;
598 ctsnap = sctp_tsnmap_get_ctsn(&ulpq->asoc->peer.tsn_map);
599 if (TSN_lte(ctsn, ctsnap))
600 retval = sctp_ulpq_retrieve_partial(ulpq);
601 }
602
603 return retval;
604}
605
606/* Retrieve the first part (sequential fragments) for partial delivery. */
607static struct sctp_ulpevent *sctp_ulpq_retrieve_first(struct sctp_ulpq *ulpq)
608{
609 struct sk_buff *pos, *last_frag, *first_frag;
610 struct sctp_ulpevent *cevent;
611 __u32 ctsn, next_tsn;
612 struct sctp_ulpevent *retval;
613
614 /* The chunks are held in the reasm queue sorted by TSN.
615 * Walk through the queue sequentially and look for a sequence of
616 * fragmented chunks that start a datagram.
617 */
618
619 if (skb_queue_empty(&ulpq->reasm))
620 return NULL;
621
622 last_frag = first_frag = NULL;
623 retval = NULL;
624 next_tsn = 0;
625
626 skb_queue_walk(&ulpq->reasm, pos) {
627 cevent = sctp_skb2event(pos);
628 ctsn = cevent->tsn;
629
630 switch (cevent->msg_flags & SCTP_DATA_FRAG_MASK) {
631 case SCTP_DATA_FIRST_FRAG:
632 if (!first_frag) {
633 first_frag = pos;
634 next_tsn = ctsn + 1;
635 last_frag = pos;
636 } else
637 goto done;
638 break;
639
640 case SCTP_DATA_MIDDLE_FRAG:
641 if (!first_frag)
642 return NULL;
643 if (ctsn == next_tsn) {
644 next_tsn++;
645 last_frag = pos;
646 } else
647 goto done;
648 break;
649 default:
650 return NULL;
651 }
652 }
653
654 /* We have the reassembled event. There is no need to look
655 * further.
656 */
657done:
658 retval = sctp_make_reassembled_event(&ulpq->reasm, first_frag, last_frag);
659 return retval;
660}
661
662/*
663 * Flush out stale fragments from the reassembly queue when processing
664 * a Forward TSN.
665 *
666 * RFC 3758, Section 3.6
667 *
668 * After receiving and processing a FORWARD TSN, the data receiver MUST
669 * take cautions in updating its re-assembly queue. The receiver MUST
670 * remove any partially reassembled message, which is still missing one
671 * or more TSNs earlier than or equal to the new cumulative TSN point.
672 * In the event that the receiver has invoked the partial delivery API,
673 * a notification SHOULD also be generated to inform the upper layer API
674 * that the message being partially delivered will NOT be completed.
675 */
676void sctp_ulpq_reasm_flushtsn(struct sctp_ulpq *ulpq, __u32 fwd_tsn)
677{
678 struct sk_buff *pos, *tmp;
679 struct sctp_ulpevent *event;
680 __u32 tsn;
681
682 if (skb_queue_empty(&ulpq->reasm))
683 return;
684
685 skb_queue_walk_safe(&ulpq->reasm, pos, tmp) {
686 event = sctp_skb2event(pos);
687 tsn = event->tsn;
688
689 /* Since the entire message must be abandoned by the
690 * sender (item A3 in Section 3.5, RFC 3758), we can
691 * free all fragments on the list that are less then
692 * or equal to ctsn_point
693 */
694 if (TSN_lte(tsn, fwd_tsn)) {
695 __skb_unlink(pos, &ulpq->reasm);
696 sctp_ulpevent_free(event);
697 } else
698 break;
699 }
700}
701
702/*
703 * Drain the reassembly queue. If we just cleared parted delivery, it
704 * is possible that the reassembly queue will contain already reassembled
705 * messages. Retrieve any such messages and give them to the user.
706 */
707static void sctp_ulpq_reasm_drain(struct sctp_ulpq *ulpq)
708{
709 struct sctp_ulpevent *event = NULL;
710 struct sk_buff_head temp;
711
712 if (skb_queue_empty(&ulpq->reasm))
713 return;
714
715 while ((event = sctp_ulpq_retrieve_reassembled(ulpq)) != NULL) {
716 /* Do ordering if needed. */
717 if ((event) && (event->msg_flags & MSG_EOR)){
718 skb_queue_head_init(&temp);
719 __skb_queue_tail(&temp, sctp_event2skb(event));
720
721 event = sctp_ulpq_order(ulpq, event);
722 }
723
724 /* Send event to the ULP. 'event' is the
725 * sctp_ulpevent for very first SKB on the temp' list.
726 */
727 if (event)
728 sctp_ulpq_tail_event(ulpq, event);
729 }
730}
731
732
733/* Helper function to gather skbs that have possibly become
734 * ordered by an an incoming chunk.
735 */
736static void sctp_ulpq_retrieve_ordered(struct sctp_ulpq *ulpq,
737 struct sctp_ulpevent *event)
738{
739 struct sk_buff_head *event_list;
740 struct sk_buff *pos, *tmp;
741 struct sctp_ulpevent *cevent;
742 struct sctp_stream *in;
743 __u16 sid, csid, cssn;
744
745 sid = event->stream;
746 in = &ulpq->asoc->ssnmap->in;
747
748 event_list = (struct sk_buff_head *) sctp_event2skb(event)->prev;
749
750 /* We are holding the chunks by stream, by SSN. */
751 sctp_skb_for_each(pos, &ulpq->lobby, tmp) {
752 cevent = (struct sctp_ulpevent *) pos->cb;
753 csid = cevent->stream;
754 cssn = cevent->ssn;
755
756 /* Have we gone too far? */
757 if (csid > sid)
758 break;
759
760 /* Have we not gone far enough? */
761 if (csid < sid)
762 continue;
763
764 if (cssn != sctp_ssn_peek(in, sid))
765 break;
766
767 /* Found it, so mark in the ssnmap. */
768 sctp_ssn_next(in, sid);
769
770 __skb_unlink(pos, &ulpq->lobby);
771
772 /* Attach all gathered skbs to the event. */
773 __skb_queue_tail(event_list, pos);
774 }
775}
776
777/* Helper function to store chunks needing ordering. */
778static void sctp_ulpq_store_ordered(struct sctp_ulpq *ulpq,
779 struct sctp_ulpevent *event)
780{
781 struct sk_buff *pos;
782 struct sctp_ulpevent *cevent;
783 __u16 sid, csid;
784 __u16 ssn, cssn;
785
786 pos = skb_peek_tail(&ulpq->lobby);
787 if (!pos) {
788 __skb_queue_tail(&ulpq->lobby, sctp_event2skb(event));
789 return;
790 }
791
792 sid = event->stream;
793 ssn = event->ssn;
794
795 cevent = (struct sctp_ulpevent *) pos->cb;
796 csid = cevent->stream;
797 cssn = cevent->ssn;
798 if (sid > csid) {
799 __skb_queue_tail(&ulpq->lobby, sctp_event2skb(event));
800 return;
801 }
802
803 if ((sid == csid) && SSN_lt(cssn, ssn)) {
804 __skb_queue_tail(&ulpq->lobby, sctp_event2skb(event));
805 return;
806 }
807
808 /* Find the right place in this list. We store them by
809 * stream ID and then by SSN.
810 */
811 skb_queue_walk(&ulpq->lobby, pos) {
812 cevent = (struct sctp_ulpevent *) pos->cb;
813 csid = cevent->stream;
814 cssn = cevent->ssn;
815
816 if (csid > sid)
817 break;
818 if (csid == sid && SSN_lt(ssn, cssn))
819 break;
820 }
821
822
823 /* Insert before pos. */
824 __skb_queue_before(&ulpq->lobby, pos, sctp_event2skb(event));
825}
826
827static struct sctp_ulpevent *sctp_ulpq_order(struct sctp_ulpq *ulpq,
828 struct sctp_ulpevent *event)
829{
830 __u16 sid, ssn;
831 struct sctp_stream *in;
832
833 /* Check if this message needs ordering. */
834 if (SCTP_DATA_UNORDERED & event->msg_flags)
835 return event;
836
837 /* Note: The stream ID must be verified before this routine. */
838 sid = event->stream;
839 ssn = event->ssn;
840 in = &ulpq->asoc->ssnmap->in;
841
842 /* Is this the expected SSN for this stream ID? */
843 if (ssn != sctp_ssn_peek(in, sid)) {
844 /* We've received something out of order, so find where it
845 * needs to be placed. We order by stream and then by SSN.
846 */
847 sctp_ulpq_store_ordered(ulpq, event);
848 return NULL;
849 }
850
851 /* Mark that the next chunk has been found. */
852 sctp_ssn_next(in, sid);
853
854 /* Go find any other chunks that were waiting for
855 * ordering.
856 */
857 sctp_ulpq_retrieve_ordered(ulpq, event);
858
859 return event;
860}
861
862/* Helper function to gather skbs that have possibly become
863 * ordered by forward tsn skipping their dependencies.
864 */
865static void sctp_ulpq_reap_ordered(struct sctp_ulpq *ulpq, __u16 sid)
866{
867 struct sk_buff *pos, *tmp;
868 struct sctp_ulpevent *cevent;
869 struct sctp_ulpevent *event;
870 struct sctp_stream *in;
871 struct sk_buff_head temp;
872 struct sk_buff_head *lobby = &ulpq->lobby;
873 __u16 csid, cssn;
874
875 in = &ulpq->asoc->ssnmap->in;
876
877 /* We are holding the chunks by stream, by SSN. */
878 skb_queue_head_init(&temp);
879 event = NULL;
880 sctp_skb_for_each(pos, lobby, tmp) {
881 cevent = (struct sctp_ulpevent *) pos->cb;
882 csid = cevent->stream;
883 cssn = cevent->ssn;
884
885 /* Have we gone too far? */
886 if (csid > sid)
887 break;
888
889 /* Have we not gone far enough? */
890 if (csid < sid)
891 continue;
892
893 /* see if this ssn has been marked by skipping */
894 if (!SSN_lt(cssn, sctp_ssn_peek(in, csid)))
895 break;
896
897 __skb_unlink(pos, lobby);
898 if (!event)
899 /* Create a temporary list to collect chunks on. */
900 event = sctp_skb2event(pos);
901
902 /* Attach all gathered skbs to the event. */
903 __skb_queue_tail(&temp, pos);
904 }
905
906 /* If we didn't reap any data, see if the next expected SSN
907 * is next on the queue and if so, use that.
908 */
909 if (event == NULL && pos != (struct sk_buff *)lobby) {
910 cevent = (struct sctp_ulpevent *) pos->cb;
911 csid = cevent->stream;
912 cssn = cevent->ssn;
913
914 if (csid == sid && cssn == sctp_ssn_peek(in, csid)) {
915 sctp_ssn_next(in, csid);
916 __skb_unlink(pos, lobby);
917 __skb_queue_tail(&temp, pos);
918 event = sctp_skb2event(pos);
919 }
920 }
921
922 /* Send event to the ULP. 'event' is the sctp_ulpevent for
923 * very first SKB on the 'temp' list.
924 */
925 if (event) {
926 /* see if we have more ordered that we can deliver */
927 sctp_ulpq_retrieve_ordered(ulpq, event);
928 sctp_ulpq_tail_event(ulpq, event);
929 }
930}
931
932/* Skip over an SSN. This is used during the processing of
933 * Forwared TSN chunk to skip over the abandoned ordered data
934 */
935void sctp_ulpq_skip(struct sctp_ulpq *ulpq, __u16 sid, __u16 ssn)
936{
937 struct sctp_stream *in;
938
939 /* Note: The stream ID must be verified before this routine. */
940 in = &ulpq->asoc->ssnmap->in;
941
942 /* Is this an old SSN? If so ignore. */
943 if (SSN_lt(ssn, sctp_ssn_peek(in, sid)))
944 return;
945
946 /* Mark that we are no longer expecting this SSN or lower. */
947 sctp_ssn_skip(in, sid, ssn);
948
949 /* Go find any other chunks that were waiting for
950 * ordering and deliver them if needed.
951 */
952 sctp_ulpq_reap_ordered(ulpq, sid);
953}
954
955static __u16 sctp_ulpq_renege_list(struct sctp_ulpq *ulpq,
956 struct sk_buff_head *list, __u16 needed)
957{
958 __u16 freed = 0;
959 __u32 tsn;
960 struct sk_buff *skb;
961 struct sctp_ulpevent *event;
962 struct sctp_tsnmap *tsnmap;
963
964 tsnmap = &ulpq->asoc->peer.tsn_map;
965
966 while ((skb = __skb_dequeue_tail(list)) != NULL) {
967 freed += skb_headlen(skb);
968 event = sctp_skb2event(skb);
969 tsn = event->tsn;
970
971 sctp_ulpevent_free(event);
972 sctp_tsnmap_renege(tsnmap, tsn);
973 if (freed >= needed)
974 return freed;
975 }
976
977 return freed;
978}
979
980/* Renege 'needed' bytes from the ordering queue. */
981static __u16 sctp_ulpq_renege_order(struct sctp_ulpq *ulpq, __u16 needed)
982{
983 return sctp_ulpq_renege_list(ulpq, &ulpq->lobby, needed);
984}
985
986/* Renege 'needed' bytes from the reassembly queue. */
987static __u16 sctp_ulpq_renege_frags(struct sctp_ulpq *ulpq, __u16 needed)
988{
989 return sctp_ulpq_renege_list(ulpq, &ulpq->reasm, needed);
990}
991
992/* Partial deliver the first message as there is pressure on rwnd. */
993void sctp_ulpq_partial_delivery(struct sctp_ulpq *ulpq,
994 struct sctp_chunk *chunk,
995 gfp_t gfp)
996{
997 struct sctp_ulpevent *event;
998 struct sctp_association *asoc;
999 struct sctp_sock *sp;
1000
1001 asoc = ulpq->asoc;
1002 sp = sctp_sk(asoc->base.sk);
1003
1004 /* If the association is already in Partial Delivery mode
1005 * we have noting to do.
1006 */
1007 if (ulpq->pd_mode)
1008 return;
1009
1010 /* If the user enabled fragment interleave socket option,
1011 * multiple associations can enter partial delivery.
1012 * Otherwise, we can only enter partial delivery if the
1013 * socket is not in partial deliver mode.
1014 */
1015 if (sp->frag_interleave || atomic_read(&sp->pd_mode) == 0) {
1016 /* Is partial delivery possible? */
1017 event = sctp_ulpq_retrieve_first(ulpq);
1018 /* Send event to the ULP. */
1019 if (event) {
1020 sctp_ulpq_tail_event(ulpq, event);
1021 sctp_ulpq_set_pd(ulpq);
1022 return;
1023 }
1024 }
1025}
1026
1027/* Renege some packets to make room for an incoming chunk. */
1028void sctp_ulpq_renege(struct sctp_ulpq *ulpq, struct sctp_chunk *chunk,
1029 gfp_t gfp)
1030{
1031 struct sctp_association *asoc;
1032 __u16 needed, freed;
1033
1034 asoc = ulpq->asoc;
1035
1036 if (chunk) {
1037 needed = ntohs(chunk->chunk_hdr->length);
1038 needed -= sizeof(sctp_data_chunk_t);
1039 } else
1040 needed = SCTP_DEFAULT_MAXWINDOW;
1041
1042 freed = 0;
1043
1044 if (skb_queue_empty(&asoc->base.sk->sk_receive_queue)) {
1045 freed = sctp_ulpq_renege_order(ulpq, needed);
1046 if (freed < needed) {
1047 freed += sctp_ulpq_renege_frags(ulpq, needed - freed);
1048 }
1049 }
1050 /* If able to free enough room, accept this chunk. */
1051 if (chunk && (freed >= needed)) {
1052 __u32 tsn;
1053 tsn = ntohl(chunk->subh.data_hdr->tsn);
1054 sctp_tsnmap_mark(&asoc->peer.tsn_map, tsn, chunk->transport);
1055 sctp_ulpq_tail_data(ulpq, chunk, gfp);
1056
1057 sctp_ulpq_partial_delivery(ulpq, chunk, gfp);
1058 }
1059
1060 sk_mem_reclaim(asoc->base.sk);
1061}
1062
1063
1064
1065/* Notify the application if an association is aborted and in
1066 * partial delivery mode. Send up any pending received messages.
1067 */
1068void sctp_ulpq_abort_pd(struct sctp_ulpq *ulpq, gfp_t gfp)
1069{
1070 struct sctp_ulpevent *ev = NULL;
1071 struct sock *sk;
1072
1073 if (!ulpq->pd_mode)
1074 return;
1075
1076 sk = ulpq->asoc->base.sk;
1077 if (sctp_ulpevent_type_enabled(SCTP_PARTIAL_DELIVERY_EVENT,
1078 &sctp_sk(sk)->subscribe))
1079 ev = sctp_ulpevent_make_pdapi(ulpq->asoc,
1080 SCTP_PARTIAL_DELIVERY_ABORTED,
1081 gfp);
1082 if (ev)
1083 __skb_queue_tail(&sk->sk_receive_queue, sctp_event2skb(ev));
1084
1085 /* If there is data waiting, send it up the socket now. */
1086 if (sctp_ulpq_clear_pd(ulpq) || ev)
1087 sk->sk_data_ready(sk, 0);
1088}
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
8 *
9 * This abstraction carries sctp events to the ULP (sockets).
10 *
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)
15 * any later version.
16 *
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.
22 *
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/>.
26 *
27 * Please send any bug reports or fixes you make to the
28 * email address(es):
29 * lksctp developers <linux-sctp@vger.kernel.org>
30 *
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>
35 */
36
37#include <linux/slab.h>
38#include <linux/types.h>
39#include <linux/skbuff.h>
40#include <net/sock.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>
45
46/* Forward declarations for internal helpers. */
47static struct sctp_ulpevent *sctp_ulpq_reasm(struct sctp_ulpq *ulpq,
48 struct sctp_ulpevent *);
49static struct sctp_ulpevent *sctp_ulpq_order(struct sctp_ulpq *,
50 struct sctp_ulpevent *);
51static void sctp_ulpq_reasm_drain(struct sctp_ulpq *ulpq);
52
53/* 1st Level Abstractions */
54
55/* Initialize a ULP queue from a block of memory. */
56struct sctp_ulpq *sctp_ulpq_init(struct sctp_ulpq *ulpq,
57 struct sctp_association *asoc)
58{
59 memset(ulpq, 0, sizeof(struct sctp_ulpq));
60
61 ulpq->asoc = asoc;
62 skb_queue_head_init(&ulpq->reasm);
63 skb_queue_head_init(&ulpq->lobby);
64 ulpq->pd_mode = 0;
65
66 return ulpq;
67}
68
69
70/* Flush the reassembly and ordering queues. */
71void sctp_ulpq_flush(struct sctp_ulpq *ulpq)
72{
73 struct sk_buff *skb;
74 struct sctp_ulpevent *event;
75
76 while ((skb = __skb_dequeue(&ulpq->lobby)) != NULL) {
77 event = sctp_skb2event(skb);
78 sctp_ulpevent_free(event);
79 }
80
81 while ((skb = __skb_dequeue(&ulpq->reasm)) != NULL) {
82 event = sctp_skb2event(skb);
83 sctp_ulpevent_free(event);
84 }
85
86}
87
88/* Dispose of a ulpqueue. */
89void sctp_ulpq_free(struct sctp_ulpq *ulpq)
90{
91 sctp_ulpq_flush(ulpq);
92}
93
94/* Process an incoming DATA chunk. */
95int sctp_ulpq_tail_data(struct sctp_ulpq *ulpq, struct sctp_chunk *chunk,
96 gfp_t gfp)
97{
98 struct sk_buff_head temp;
99 struct sctp_ulpevent *event;
100 int event_eor = 0;
101
102 /* Create an event from the incoming chunk. */
103 event = sctp_ulpevent_make_rcvmsg(chunk->asoc, chunk, gfp);
104 if (!event)
105 return -ENOMEM;
106
107 /* Do reassembly if needed. */
108 event = sctp_ulpq_reasm(ulpq, event);
109
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));
115
116 event = sctp_ulpq_order(ulpq, event);
117 }
118
119 /* Send event to the ULP. 'event' is the sctp_ulpevent for
120 * very first SKB on the 'temp' list.
121 */
122 if (event) {
123 event_eor = (event->msg_flags & MSG_EOR) ? 1 : 0;
124 sctp_ulpq_tail_event(ulpq, event);
125 }
126
127 return event_eor;
128}
129
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.
133 */
134int sctp_clear_pd(struct sock *sk, struct sctp_association *asoc)
135{
136 struct sctp_sock *sp = sctp_sk(sk);
137
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
141 */
142 if (!skb_queue_empty(&sp->pd_lobby)) {
143 struct list_head *list;
144 sctp_skb_list_tail(&sp->pd_lobby, &sk->sk_receive_queue);
145 list = (struct list_head *)&sctp_sk(sk)->pd_lobby;
146 INIT_LIST_HEAD(list);
147 return 1;
148 }
149 } else {
150 /* There are other associations in PD, so we only need to
151 * pull stuff out of the lobby that belongs to the
152 * associations that is exiting PD (all of its notifications
153 * are posted here).
154 */
155 if (!skb_queue_empty(&sp->pd_lobby) && asoc) {
156 struct sk_buff *skb, *tmp;
157 struct sctp_ulpevent *event;
158
159 sctp_skb_for_each(skb, &sp->pd_lobby, tmp) {
160 event = sctp_skb2event(skb);
161 if (event->asoc == asoc) {
162 __skb_unlink(skb, &sp->pd_lobby);
163 __skb_queue_tail(&sk->sk_receive_queue,
164 skb);
165 }
166 }
167 }
168 }
169
170 return 0;
171}
172
173/* Set the pd_mode on the socket and ulpq */
174static void sctp_ulpq_set_pd(struct sctp_ulpq *ulpq)
175{
176 struct sctp_sock *sp = sctp_sk(ulpq->asoc->base.sk);
177
178 atomic_inc(&sp->pd_mode);
179 ulpq->pd_mode = 1;
180}
181
182/* Clear the pd_mode and restart any pending messages waiting for delivery. */
183static int sctp_ulpq_clear_pd(struct sctp_ulpq *ulpq)
184{
185 ulpq->pd_mode = 0;
186 sctp_ulpq_reasm_drain(ulpq);
187 return sctp_clear_pd(ulpq->asoc->base.sk, ulpq->asoc);
188}
189
190/* If the SKB of 'event' is on a list, it is the first such member
191 * of that list.
192 */
193int sctp_ulpq_tail_event(struct sctp_ulpq *ulpq, struct sctp_ulpevent *event)
194{
195 struct sock *sk = ulpq->asoc->base.sk;
196 struct sk_buff_head *queue, *skb_list;
197 struct sk_buff *skb = sctp_event2skb(event);
198 int clear_pd = 0;
199
200 skb_list = (struct sk_buff_head *) skb->prev;
201
202 /* If the socket is just going to throw this away, do not
203 * even try to deliver it.
204 */
205 if (sock_flag(sk, SOCK_DEAD) || (sk->sk_shutdown & RCV_SHUTDOWN))
206 goto out_free;
207
208 if (!sctp_ulpevent_is_notification(event)) {
209 sk_mark_napi_id(sk, skb);
210 sk_incoming_cpu_update(sk);
211 }
212 /* Check if the user wishes to receive this event. */
213 if (!sctp_ulpevent_is_enabled(event, &sctp_sk(sk)->subscribe))
214 goto out_free;
215
216 /* If we are in partial delivery mode, post to the lobby until
217 * partial delivery is cleared, unless, of course _this_ is
218 * the association the cause of the partial delivery.
219 */
220
221 if (atomic_read(&sctp_sk(sk)->pd_mode) == 0) {
222 queue = &sk->sk_receive_queue;
223 } else {
224 if (ulpq->pd_mode) {
225 /* If the association is in partial delivery, we
226 * need to finish delivering the partially processed
227 * packet before passing any other data. This is
228 * because we don't truly support stream interleaving.
229 */
230 if ((event->msg_flags & MSG_NOTIFICATION) ||
231 (SCTP_DATA_NOT_FRAG ==
232 (event->msg_flags & SCTP_DATA_FRAG_MASK)))
233 queue = &sctp_sk(sk)->pd_lobby;
234 else {
235 clear_pd = event->msg_flags & MSG_EOR;
236 queue = &sk->sk_receive_queue;
237 }
238 } else {
239 /*
240 * If fragment interleave is enabled, we
241 * can queue this to the receive queue instead
242 * of the lobby.
243 */
244 if (sctp_sk(sk)->frag_interleave)
245 queue = &sk->sk_receive_queue;
246 else
247 queue = &sctp_sk(sk)->pd_lobby;
248 }
249 }
250
251 /* If we are harvesting multiple skbs they will be
252 * collected on a list.
253 */
254 if (skb_list)
255 sctp_skb_list_tail(skb_list, queue);
256 else
257 __skb_queue_tail(queue, skb);
258
259 /* Did we just complete partial delivery and need to get
260 * rolling again? Move pending data to the receive
261 * queue.
262 */
263 if (clear_pd)
264 sctp_ulpq_clear_pd(ulpq);
265
266 if (queue == &sk->sk_receive_queue)
267 sk->sk_data_ready(sk);
268 return 1;
269
270out_free:
271 if (skb_list)
272 sctp_queue_purge_ulpevents(skb_list);
273 else
274 sctp_ulpevent_free(event);
275
276 return 0;
277}
278
279/* 2nd Level Abstractions */
280
281/* Helper function to store chunks that need to be reassembled. */
282static void sctp_ulpq_store_reasm(struct sctp_ulpq *ulpq,
283 struct sctp_ulpevent *event)
284{
285 struct sk_buff *pos;
286 struct sctp_ulpevent *cevent;
287 __u32 tsn, ctsn;
288
289 tsn = event->tsn;
290
291 /* See if it belongs at the end. */
292 pos = skb_peek_tail(&ulpq->reasm);
293 if (!pos) {
294 __skb_queue_tail(&ulpq->reasm, sctp_event2skb(event));
295 return;
296 }
297
298 /* Short circuit just dropping it at the end. */
299 cevent = sctp_skb2event(pos);
300 ctsn = cevent->tsn;
301 if (TSN_lt(ctsn, tsn)) {
302 __skb_queue_tail(&ulpq->reasm, sctp_event2skb(event));
303 return;
304 }
305
306 /* Find the right place in this list. We store them by TSN. */
307 skb_queue_walk(&ulpq->reasm, pos) {
308 cevent = sctp_skb2event(pos);
309 ctsn = cevent->tsn;
310
311 if (TSN_lt(tsn, ctsn))
312 break;
313 }
314
315 /* Insert before pos. */
316 __skb_queue_before(&ulpq->reasm, pos, sctp_event2skb(event));
317
318}
319
320/* Helper function to return an event corresponding to the reassembled
321 * datagram.
322 * This routine creates a re-assembled skb given the first and last skb's
323 * as stored in the reassembly queue. The skb's may be non-linear if the sctp
324 * payload was fragmented on the way and ip had to reassemble them.
325 * We add the rest of skb's to the first skb's fraglist.
326 */
327static struct sctp_ulpevent *sctp_make_reassembled_event(struct net *net,
328 struct sk_buff_head *queue, struct sk_buff *f_frag,
329 struct sk_buff *l_frag)
330{
331 struct sk_buff *pos;
332 struct sk_buff *new = NULL;
333 struct sctp_ulpevent *event;
334 struct sk_buff *pnext, *last;
335 struct sk_buff *list = skb_shinfo(f_frag)->frag_list;
336
337 /* Store the pointer to the 2nd skb */
338 if (f_frag == l_frag)
339 pos = NULL;
340 else
341 pos = f_frag->next;
342
343 /* Get the last skb in the f_frag's frag_list if present. */
344 for (last = list; list; last = list, list = list->next)
345 ;
346
347 /* Add the list of remaining fragments to the first fragments
348 * frag_list.
349 */
350 if (last)
351 last->next = pos;
352 else {
353 if (skb_cloned(f_frag)) {
354 /* This is a cloned skb, we can't just modify
355 * the frag_list. We need a new skb to do that.
356 * Instead of calling skb_unshare(), we'll do it
357 * ourselves since we need to delay the free.
358 */
359 new = skb_copy(f_frag, GFP_ATOMIC);
360 if (!new)
361 return NULL; /* try again later */
362
363 sctp_skb_set_owner_r(new, f_frag->sk);
364
365 skb_shinfo(new)->frag_list = pos;
366 } else
367 skb_shinfo(f_frag)->frag_list = pos;
368 }
369
370 /* Remove the first fragment from the reassembly queue. */
371 __skb_unlink(f_frag, queue);
372
373 /* if we did unshare, then free the old skb and re-assign */
374 if (new) {
375 kfree_skb(f_frag);
376 f_frag = new;
377 }
378
379 while (pos) {
380
381 pnext = pos->next;
382
383 /* Update the len and data_len fields of the first fragment. */
384 f_frag->len += pos->len;
385 f_frag->data_len += pos->len;
386
387 /* Remove the fragment from the reassembly queue. */
388 __skb_unlink(pos, queue);
389
390 /* Break if we have reached the last fragment. */
391 if (pos == l_frag)
392 break;
393 pos->next = pnext;
394 pos = pnext;
395 }
396
397 event = sctp_skb2event(f_frag);
398 SCTP_INC_STATS(net, SCTP_MIB_REASMUSRMSGS);
399
400 return event;
401}
402
403
404/* Helper function to check if an incoming chunk has filled up the last
405 * missing fragment in a SCTP datagram and return the corresponding event.
406 */
407static struct sctp_ulpevent *sctp_ulpq_retrieve_reassembled(struct sctp_ulpq *ulpq)
408{
409 struct sk_buff *pos;
410 struct sctp_ulpevent *cevent;
411 struct sk_buff *first_frag = NULL;
412 __u32 ctsn, next_tsn;
413 struct sctp_ulpevent *retval = NULL;
414 struct sk_buff *pd_first = NULL;
415 struct sk_buff *pd_last = NULL;
416 size_t pd_len = 0;
417 struct sctp_association *asoc;
418 u32 pd_point;
419
420 /* Initialized to 0 just to avoid compiler warning message. Will
421 * never be used with this value. It is referenced only after it
422 * is set when we find the first fragment of a message.
423 */
424 next_tsn = 0;
425
426 /* The chunks are held in the reasm queue sorted by TSN.
427 * Walk through the queue sequentially and look for a sequence of
428 * fragmented chunks that complete a datagram.
429 * 'first_frag' and next_tsn are reset when we find a chunk which
430 * is the first fragment of a datagram. Once these 2 fields are set
431 * we expect to find the remaining middle fragments and the last
432 * fragment in order. If not, first_frag is reset to NULL and we
433 * start the next pass when we find another first fragment.
434 *
435 * There is a potential to do partial delivery if user sets
436 * SCTP_PARTIAL_DELIVERY_POINT option. Lets count some things here
437 * to see if can do PD.
438 */
439 skb_queue_walk(&ulpq->reasm, pos) {
440 cevent = sctp_skb2event(pos);
441 ctsn = cevent->tsn;
442
443 switch (cevent->msg_flags & SCTP_DATA_FRAG_MASK) {
444 case SCTP_DATA_FIRST_FRAG:
445 /* If this "FIRST_FRAG" is the first
446 * element in the queue, then count it towards
447 * possible PD.
448 */
449 if (pos == ulpq->reasm.next) {
450 pd_first = pos;
451 pd_last = pos;
452 pd_len = pos->len;
453 } else {
454 pd_first = NULL;
455 pd_last = NULL;
456 pd_len = 0;
457 }
458
459 first_frag = pos;
460 next_tsn = ctsn + 1;
461 break;
462
463 case SCTP_DATA_MIDDLE_FRAG:
464 if ((first_frag) && (ctsn == next_tsn)) {
465 next_tsn++;
466 if (pd_first) {
467 pd_last = pos;
468 pd_len += pos->len;
469 }
470 } else
471 first_frag = NULL;
472 break;
473
474 case SCTP_DATA_LAST_FRAG:
475 if (first_frag && (ctsn == next_tsn))
476 goto found;
477 else
478 first_frag = NULL;
479 break;
480 }
481 }
482
483 asoc = ulpq->asoc;
484 if (pd_first) {
485 /* Make sure we can enter partial deliver.
486 * We can trigger partial delivery only if framgent
487 * interleave is set, or the socket is not already
488 * in partial delivery.
489 */
490 if (!sctp_sk(asoc->base.sk)->frag_interleave &&
491 atomic_read(&sctp_sk(asoc->base.sk)->pd_mode))
492 goto done;
493
494 cevent = sctp_skb2event(pd_first);
495 pd_point = sctp_sk(asoc->base.sk)->pd_point;
496 if (pd_point && pd_point <= pd_len) {
497 retval = sctp_make_reassembled_event(sock_net(asoc->base.sk),
498 &ulpq->reasm,
499 pd_first,
500 pd_last);
501 if (retval)
502 sctp_ulpq_set_pd(ulpq);
503 }
504 }
505done:
506 return retval;
507found:
508 retval = sctp_make_reassembled_event(sock_net(ulpq->asoc->base.sk),
509 &ulpq->reasm, first_frag, pos);
510 if (retval)
511 retval->msg_flags |= MSG_EOR;
512 goto done;
513}
514
515/* Retrieve the next set of fragments of a partial message. */
516static struct sctp_ulpevent *sctp_ulpq_retrieve_partial(struct sctp_ulpq *ulpq)
517{
518 struct sk_buff *pos, *last_frag, *first_frag;
519 struct sctp_ulpevent *cevent;
520 __u32 ctsn, next_tsn;
521 int is_last;
522 struct sctp_ulpevent *retval;
523
524 /* The chunks are held in the reasm queue sorted by TSN.
525 * Walk through the queue sequentially and look for the first
526 * sequence of fragmented chunks.
527 */
528
529 if (skb_queue_empty(&ulpq->reasm))
530 return NULL;
531
532 last_frag = first_frag = NULL;
533 retval = NULL;
534 next_tsn = 0;
535 is_last = 0;
536
537 skb_queue_walk(&ulpq->reasm, pos) {
538 cevent = sctp_skb2event(pos);
539 ctsn = cevent->tsn;
540
541 switch (cevent->msg_flags & SCTP_DATA_FRAG_MASK) {
542 case SCTP_DATA_FIRST_FRAG:
543 if (!first_frag)
544 return NULL;
545 goto done;
546 case SCTP_DATA_MIDDLE_FRAG:
547 if (!first_frag) {
548 first_frag = pos;
549 next_tsn = ctsn + 1;
550 last_frag = pos;
551 } else if (next_tsn == ctsn) {
552 next_tsn++;
553 last_frag = pos;
554 } else
555 goto done;
556 break;
557 case SCTP_DATA_LAST_FRAG:
558 if (!first_frag)
559 first_frag = pos;
560 else if (ctsn != next_tsn)
561 goto done;
562 last_frag = pos;
563 is_last = 1;
564 goto done;
565 default:
566 return NULL;
567 }
568 }
569
570 /* We have the reassembled event. There is no need to look
571 * further.
572 */
573done:
574 retval = sctp_make_reassembled_event(sock_net(ulpq->asoc->base.sk),
575 &ulpq->reasm, first_frag, last_frag);
576 if (retval && is_last)
577 retval->msg_flags |= MSG_EOR;
578
579 return retval;
580}
581
582
583/* Helper function to reassemble chunks. Hold chunks on the reasm queue that
584 * need reassembling.
585 */
586static struct sctp_ulpevent *sctp_ulpq_reasm(struct sctp_ulpq *ulpq,
587 struct sctp_ulpevent *event)
588{
589 struct sctp_ulpevent *retval = NULL;
590
591 /* Check if this is part of a fragmented message. */
592 if (SCTP_DATA_NOT_FRAG == (event->msg_flags & SCTP_DATA_FRAG_MASK)) {
593 event->msg_flags |= MSG_EOR;
594 return event;
595 }
596
597 sctp_ulpq_store_reasm(ulpq, event);
598 if (!ulpq->pd_mode)
599 retval = sctp_ulpq_retrieve_reassembled(ulpq);
600 else {
601 __u32 ctsn, ctsnap;
602
603 /* Do not even bother unless this is the next tsn to
604 * be delivered.
605 */
606 ctsn = event->tsn;
607 ctsnap = sctp_tsnmap_get_ctsn(&ulpq->asoc->peer.tsn_map);
608 if (TSN_lte(ctsn, ctsnap))
609 retval = sctp_ulpq_retrieve_partial(ulpq);
610 }
611
612 return retval;
613}
614
615/* Retrieve the first part (sequential fragments) for partial delivery. */
616static struct sctp_ulpevent *sctp_ulpq_retrieve_first(struct sctp_ulpq *ulpq)
617{
618 struct sk_buff *pos, *last_frag, *first_frag;
619 struct sctp_ulpevent *cevent;
620 __u32 ctsn, next_tsn;
621 struct sctp_ulpevent *retval;
622
623 /* The chunks are held in the reasm queue sorted by TSN.
624 * Walk through the queue sequentially and look for a sequence of
625 * fragmented chunks that start a datagram.
626 */
627
628 if (skb_queue_empty(&ulpq->reasm))
629 return NULL;
630
631 last_frag = first_frag = NULL;
632 retval = NULL;
633 next_tsn = 0;
634
635 skb_queue_walk(&ulpq->reasm, pos) {
636 cevent = sctp_skb2event(pos);
637 ctsn = cevent->tsn;
638
639 switch (cevent->msg_flags & SCTP_DATA_FRAG_MASK) {
640 case SCTP_DATA_FIRST_FRAG:
641 if (!first_frag) {
642 first_frag = pos;
643 next_tsn = ctsn + 1;
644 last_frag = pos;
645 } else
646 goto done;
647 break;
648
649 case SCTP_DATA_MIDDLE_FRAG:
650 if (!first_frag)
651 return NULL;
652 if (ctsn == next_tsn) {
653 next_tsn++;
654 last_frag = pos;
655 } else
656 goto done;
657 break;
658
659 case SCTP_DATA_LAST_FRAG:
660 if (!first_frag)
661 return NULL;
662 else
663 goto done;
664 break;
665
666 default:
667 return NULL;
668 }
669 }
670
671 /* We have the reassembled event. There is no need to look
672 * further.
673 */
674done:
675 retval = sctp_make_reassembled_event(sock_net(ulpq->asoc->base.sk),
676 &ulpq->reasm, first_frag, last_frag);
677 return retval;
678}
679
680/*
681 * Flush out stale fragments from the reassembly queue when processing
682 * a Forward TSN.
683 *
684 * RFC 3758, Section 3.6
685 *
686 * After receiving and processing a FORWARD TSN, the data receiver MUST
687 * take cautions in updating its re-assembly queue. The receiver MUST
688 * remove any partially reassembled message, which is still missing one
689 * or more TSNs earlier than or equal to the new cumulative TSN point.
690 * In the event that the receiver has invoked the partial delivery API,
691 * a notification SHOULD also be generated to inform the upper layer API
692 * that the message being partially delivered will NOT be completed.
693 */
694void sctp_ulpq_reasm_flushtsn(struct sctp_ulpq *ulpq, __u32 fwd_tsn)
695{
696 struct sk_buff *pos, *tmp;
697 struct sctp_ulpevent *event;
698 __u32 tsn;
699
700 if (skb_queue_empty(&ulpq->reasm))
701 return;
702
703 skb_queue_walk_safe(&ulpq->reasm, pos, tmp) {
704 event = sctp_skb2event(pos);
705 tsn = event->tsn;
706
707 /* Since the entire message must be abandoned by the
708 * sender (item A3 in Section 3.5, RFC 3758), we can
709 * free all fragments on the list that are less then
710 * or equal to ctsn_point
711 */
712 if (TSN_lte(tsn, fwd_tsn)) {
713 __skb_unlink(pos, &ulpq->reasm);
714 sctp_ulpevent_free(event);
715 } else
716 break;
717 }
718}
719
720/*
721 * Drain the reassembly queue. If we just cleared parted delivery, it
722 * is possible that the reassembly queue will contain already reassembled
723 * messages. Retrieve any such messages and give them to the user.
724 */
725static void sctp_ulpq_reasm_drain(struct sctp_ulpq *ulpq)
726{
727 struct sctp_ulpevent *event = NULL;
728 struct sk_buff_head temp;
729
730 if (skb_queue_empty(&ulpq->reasm))
731 return;
732
733 while ((event = sctp_ulpq_retrieve_reassembled(ulpq)) != NULL) {
734 /* Do ordering if needed. */
735 if ((event) && (event->msg_flags & MSG_EOR)) {
736 skb_queue_head_init(&temp);
737 __skb_queue_tail(&temp, sctp_event2skb(event));
738
739 event = sctp_ulpq_order(ulpq, event);
740 }
741
742 /* Send event to the ULP. 'event' is the
743 * sctp_ulpevent for very first SKB on the temp' list.
744 */
745 if (event)
746 sctp_ulpq_tail_event(ulpq, event);
747 }
748}
749
750
751/* Helper function to gather skbs that have possibly become
752 * ordered by an an incoming chunk.
753 */
754static void sctp_ulpq_retrieve_ordered(struct sctp_ulpq *ulpq,
755 struct sctp_ulpevent *event)
756{
757 struct sk_buff_head *event_list;
758 struct sk_buff *pos, *tmp;
759 struct sctp_ulpevent *cevent;
760 struct sctp_stream *in;
761 __u16 sid, csid, cssn;
762
763 sid = event->stream;
764 in = &ulpq->asoc->ssnmap->in;
765
766 event_list = (struct sk_buff_head *) sctp_event2skb(event)->prev;
767
768 /* We are holding the chunks by stream, by SSN. */
769 sctp_skb_for_each(pos, &ulpq->lobby, tmp) {
770 cevent = (struct sctp_ulpevent *) pos->cb;
771 csid = cevent->stream;
772 cssn = cevent->ssn;
773
774 /* Have we gone too far? */
775 if (csid > sid)
776 break;
777
778 /* Have we not gone far enough? */
779 if (csid < sid)
780 continue;
781
782 if (cssn != sctp_ssn_peek(in, sid))
783 break;
784
785 /* Found it, so mark in the ssnmap. */
786 sctp_ssn_next(in, sid);
787
788 __skb_unlink(pos, &ulpq->lobby);
789
790 /* Attach all gathered skbs to the event. */
791 __skb_queue_tail(event_list, pos);
792 }
793}
794
795/* Helper function to store chunks needing ordering. */
796static void sctp_ulpq_store_ordered(struct sctp_ulpq *ulpq,
797 struct sctp_ulpevent *event)
798{
799 struct sk_buff *pos;
800 struct sctp_ulpevent *cevent;
801 __u16 sid, csid;
802 __u16 ssn, cssn;
803
804 pos = skb_peek_tail(&ulpq->lobby);
805 if (!pos) {
806 __skb_queue_tail(&ulpq->lobby, sctp_event2skb(event));
807 return;
808 }
809
810 sid = event->stream;
811 ssn = event->ssn;
812
813 cevent = (struct sctp_ulpevent *) pos->cb;
814 csid = cevent->stream;
815 cssn = cevent->ssn;
816 if (sid > csid) {
817 __skb_queue_tail(&ulpq->lobby, sctp_event2skb(event));
818 return;
819 }
820
821 if ((sid == csid) && SSN_lt(cssn, ssn)) {
822 __skb_queue_tail(&ulpq->lobby, sctp_event2skb(event));
823 return;
824 }
825
826 /* Find the right place in this list. We store them by
827 * stream ID and then by SSN.
828 */
829 skb_queue_walk(&ulpq->lobby, pos) {
830 cevent = (struct sctp_ulpevent *) pos->cb;
831 csid = cevent->stream;
832 cssn = cevent->ssn;
833
834 if (csid > sid)
835 break;
836 if (csid == sid && SSN_lt(ssn, cssn))
837 break;
838 }
839
840
841 /* Insert before pos. */
842 __skb_queue_before(&ulpq->lobby, pos, sctp_event2skb(event));
843}
844
845static struct sctp_ulpevent *sctp_ulpq_order(struct sctp_ulpq *ulpq,
846 struct sctp_ulpevent *event)
847{
848 __u16 sid, ssn;
849 struct sctp_stream *in;
850
851 /* Check if this message needs ordering. */
852 if (SCTP_DATA_UNORDERED & event->msg_flags)
853 return event;
854
855 /* Note: The stream ID must be verified before this routine. */
856 sid = event->stream;
857 ssn = event->ssn;
858 in = &ulpq->asoc->ssnmap->in;
859
860 /* Is this the expected SSN for this stream ID? */
861 if (ssn != sctp_ssn_peek(in, sid)) {
862 /* We've received something out of order, so find where it
863 * needs to be placed. We order by stream and then by SSN.
864 */
865 sctp_ulpq_store_ordered(ulpq, event);
866 return NULL;
867 }
868
869 /* Mark that the next chunk has been found. */
870 sctp_ssn_next(in, sid);
871
872 /* Go find any other chunks that were waiting for
873 * ordering.
874 */
875 sctp_ulpq_retrieve_ordered(ulpq, event);
876
877 return event;
878}
879
880/* Helper function to gather skbs that have possibly become
881 * ordered by forward tsn skipping their dependencies.
882 */
883static void sctp_ulpq_reap_ordered(struct sctp_ulpq *ulpq, __u16 sid)
884{
885 struct sk_buff *pos, *tmp;
886 struct sctp_ulpevent *cevent;
887 struct sctp_ulpevent *event;
888 struct sctp_stream *in;
889 struct sk_buff_head temp;
890 struct sk_buff_head *lobby = &ulpq->lobby;
891 __u16 csid, cssn;
892
893 in = &ulpq->asoc->ssnmap->in;
894
895 /* We are holding the chunks by stream, by SSN. */
896 skb_queue_head_init(&temp);
897 event = NULL;
898 sctp_skb_for_each(pos, lobby, tmp) {
899 cevent = (struct sctp_ulpevent *) pos->cb;
900 csid = cevent->stream;
901 cssn = cevent->ssn;
902
903 /* Have we gone too far? */
904 if (csid > sid)
905 break;
906
907 /* Have we not gone far enough? */
908 if (csid < sid)
909 continue;
910
911 /* see if this ssn has been marked by skipping */
912 if (!SSN_lt(cssn, sctp_ssn_peek(in, csid)))
913 break;
914
915 __skb_unlink(pos, lobby);
916 if (!event)
917 /* Create a temporary list to collect chunks on. */
918 event = sctp_skb2event(pos);
919
920 /* Attach all gathered skbs to the event. */
921 __skb_queue_tail(&temp, pos);
922 }
923
924 /* If we didn't reap any data, see if the next expected SSN
925 * is next on the queue and if so, use that.
926 */
927 if (event == NULL && pos != (struct sk_buff *)lobby) {
928 cevent = (struct sctp_ulpevent *) pos->cb;
929 csid = cevent->stream;
930 cssn = cevent->ssn;
931
932 if (csid == sid && cssn == sctp_ssn_peek(in, csid)) {
933 sctp_ssn_next(in, csid);
934 __skb_unlink(pos, lobby);
935 __skb_queue_tail(&temp, pos);
936 event = sctp_skb2event(pos);
937 }
938 }
939
940 /* Send event to the ULP. 'event' is the sctp_ulpevent for
941 * very first SKB on the 'temp' list.
942 */
943 if (event) {
944 /* see if we have more ordered that we can deliver */
945 sctp_ulpq_retrieve_ordered(ulpq, event);
946 sctp_ulpq_tail_event(ulpq, event);
947 }
948}
949
950/* Skip over an SSN. This is used during the processing of
951 * Forwared TSN chunk to skip over the abandoned ordered data
952 */
953void sctp_ulpq_skip(struct sctp_ulpq *ulpq, __u16 sid, __u16 ssn)
954{
955 struct sctp_stream *in;
956
957 /* Note: The stream ID must be verified before this routine. */
958 in = &ulpq->asoc->ssnmap->in;
959
960 /* Is this an old SSN? If so ignore. */
961 if (SSN_lt(ssn, sctp_ssn_peek(in, sid)))
962 return;
963
964 /* Mark that we are no longer expecting this SSN or lower. */
965 sctp_ssn_skip(in, sid, ssn);
966
967 /* Go find any other chunks that were waiting for
968 * ordering and deliver them if needed.
969 */
970 sctp_ulpq_reap_ordered(ulpq, sid);
971}
972
973static __u16 sctp_ulpq_renege_list(struct sctp_ulpq *ulpq,
974 struct sk_buff_head *list, __u16 needed)
975{
976 __u16 freed = 0;
977 __u32 tsn, last_tsn;
978 struct sk_buff *skb, *flist, *last;
979 struct sctp_ulpevent *event;
980 struct sctp_tsnmap *tsnmap;
981
982 tsnmap = &ulpq->asoc->peer.tsn_map;
983
984 while ((skb = skb_peek_tail(list)) != NULL) {
985 event = sctp_skb2event(skb);
986 tsn = event->tsn;
987
988 /* Don't renege below the Cumulative TSN ACK Point. */
989 if (TSN_lte(tsn, sctp_tsnmap_get_ctsn(tsnmap)))
990 break;
991
992 /* Events in ordering queue may have multiple fragments
993 * corresponding to additional TSNs. Sum the total
994 * freed space; find the last TSN.
995 */
996 freed += skb_headlen(skb);
997 flist = skb_shinfo(skb)->frag_list;
998 for (last = flist; flist; flist = flist->next) {
999 last = flist;
1000 freed += skb_headlen(last);
1001 }
1002 if (last)
1003 last_tsn = sctp_skb2event(last)->tsn;
1004 else
1005 last_tsn = tsn;
1006
1007 /* Unlink the event, then renege all applicable TSNs. */
1008 __skb_unlink(skb, list);
1009 sctp_ulpevent_free(event);
1010 while (TSN_lte(tsn, last_tsn)) {
1011 sctp_tsnmap_renege(tsnmap, tsn);
1012 tsn++;
1013 }
1014 if (freed >= needed)
1015 return freed;
1016 }
1017
1018 return freed;
1019}
1020
1021/* Renege 'needed' bytes from the ordering queue. */
1022static __u16 sctp_ulpq_renege_order(struct sctp_ulpq *ulpq, __u16 needed)
1023{
1024 return sctp_ulpq_renege_list(ulpq, &ulpq->lobby, needed);
1025}
1026
1027/* Renege 'needed' bytes from the reassembly queue. */
1028static __u16 sctp_ulpq_renege_frags(struct sctp_ulpq *ulpq, __u16 needed)
1029{
1030 return sctp_ulpq_renege_list(ulpq, &ulpq->reasm, needed);
1031}
1032
1033/* Partial deliver the first message as there is pressure on rwnd. */
1034void sctp_ulpq_partial_delivery(struct sctp_ulpq *ulpq,
1035 gfp_t gfp)
1036{
1037 struct sctp_ulpevent *event;
1038 struct sctp_association *asoc;
1039 struct sctp_sock *sp;
1040 __u32 ctsn;
1041 struct sk_buff *skb;
1042
1043 asoc = ulpq->asoc;
1044 sp = sctp_sk(asoc->base.sk);
1045
1046 /* If the association is already in Partial Delivery mode
1047 * we have nothing to do.
1048 */
1049 if (ulpq->pd_mode)
1050 return;
1051
1052 /* Data must be at or below the Cumulative TSN ACK Point to
1053 * start partial delivery.
1054 */
1055 skb = skb_peek(&asoc->ulpq.reasm);
1056 if (skb != NULL) {
1057 ctsn = sctp_skb2event(skb)->tsn;
1058 if (!TSN_lte(ctsn, sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map)))
1059 return;
1060 }
1061
1062 /* If the user enabled fragment interleave socket option,
1063 * multiple associations can enter partial delivery.
1064 * Otherwise, we can only enter partial delivery if the
1065 * socket is not in partial deliver mode.
1066 */
1067 if (sp->frag_interleave || atomic_read(&sp->pd_mode) == 0) {
1068 /* Is partial delivery possible? */
1069 event = sctp_ulpq_retrieve_first(ulpq);
1070 /* Send event to the ULP. */
1071 if (event) {
1072 sctp_ulpq_tail_event(ulpq, event);
1073 sctp_ulpq_set_pd(ulpq);
1074 return;
1075 }
1076 }
1077}
1078
1079/* Renege some packets to make room for an incoming chunk. */
1080void sctp_ulpq_renege(struct sctp_ulpq *ulpq, struct sctp_chunk *chunk,
1081 gfp_t gfp)
1082{
1083 struct sctp_association *asoc;
1084 __u16 needed, freed;
1085
1086 asoc = ulpq->asoc;
1087
1088 if (chunk) {
1089 needed = ntohs(chunk->chunk_hdr->length);
1090 needed -= sizeof(sctp_data_chunk_t);
1091 } else
1092 needed = SCTP_DEFAULT_MAXWINDOW;
1093
1094 freed = 0;
1095
1096 if (skb_queue_empty(&asoc->base.sk->sk_receive_queue)) {
1097 freed = sctp_ulpq_renege_order(ulpq, needed);
1098 if (freed < needed) {
1099 freed += sctp_ulpq_renege_frags(ulpq, needed - freed);
1100 }
1101 }
1102 /* If able to free enough room, accept this chunk. */
1103 if (chunk && (freed >= needed)) {
1104 int retval;
1105 retval = sctp_ulpq_tail_data(ulpq, chunk, gfp);
1106 /*
1107 * Enter partial delivery if chunk has not been
1108 * delivered; otherwise, drain the reassembly queue.
1109 */
1110 if (retval <= 0)
1111 sctp_ulpq_partial_delivery(ulpq, gfp);
1112 else if (retval == 1)
1113 sctp_ulpq_reasm_drain(ulpq);
1114 }
1115
1116 sk_mem_reclaim(asoc->base.sk);
1117}
1118
1119
1120
1121/* Notify the application if an association is aborted and in
1122 * partial delivery mode. Send up any pending received messages.
1123 */
1124void sctp_ulpq_abort_pd(struct sctp_ulpq *ulpq, gfp_t gfp)
1125{
1126 struct sctp_ulpevent *ev = NULL;
1127 struct sock *sk;
1128
1129 if (!ulpq->pd_mode)
1130 return;
1131
1132 sk = ulpq->asoc->base.sk;
1133 if (sctp_ulpevent_type_enabled(SCTP_PARTIAL_DELIVERY_EVENT,
1134 &sctp_sk(sk)->subscribe))
1135 ev = sctp_ulpevent_make_pdapi(ulpq->asoc,
1136 SCTP_PARTIAL_DELIVERY_ABORTED,
1137 gfp);
1138 if (ev)
1139 __skb_queue_tail(&sk->sk_receive_queue, sctp_event2skb(ev));
1140
1141 /* If there is data waiting, send it up the socket now. */
1142 if (sctp_ulpq_clear_pd(ulpq) || ev)
1143 sk->sk_data_ready(sk);
1144}