blob: 2080b2d28c98e97297fae432fc1a3a97a68f2646 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* SCTP kernel reference 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 * The SCTP reference 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 * The SCTP reference 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/types.h>
45#include <linux/skbuff.h>
46#include <net/sock.h>
47#include <net/sctp/structs.h>
48#include <net/sctp/sctp.h>
49#include <net/sctp/sm.h>
50
51/* Forward declarations for internal helpers. */
52static struct sctp_ulpevent * sctp_ulpq_reasm(struct sctp_ulpq *ulpq,
David S. Miller8728b832005-08-09 19:25:21 -070053 struct sctp_ulpevent *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070054static struct sctp_ulpevent * sctp_ulpq_order(struct sctp_ulpq *,
David S. Miller8728b832005-08-09 19:25:21 -070055 struct sctp_ulpevent *);
Linus Torvalds1da177e2005-04-16 15:20:36 -070056
57/* 1st Level Abstractions */
58
59/* Initialize a ULP queue from a block of memory. */
60struct sctp_ulpq *sctp_ulpq_init(struct sctp_ulpq *ulpq,
61 struct sctp_association *asoc)
62{
63 memset(ulpq, 0, sizeof(struct sctp_ulpq));
64
65 ulpq->asoc = asoc;
66 skb_queue_head_init(&ulpq->reasm);
67 skb_queue_head_init(&ulpq->lobby);
68 ulpq->pd_mode = 0;
69 ulpq->malloced = 0;
70
71 return ulpq;
72}
73
74
75/* Flush the reassembly and ordering queues. */
76static void sctp_ulpq_flush(struct sctp_ulpq *ulpq)
77{
78 struct sk_buff *skb;
79 struct sctp_ulpevent *event;
80
81 while ((skb = __skb_dequeue(&ulpq->lobby)) != NULL) {
82 event = sctp_skb2event(skb);
83 sctp_ulpevent_free(event);
84 }
85
86 while ((skb = __skb_dequeue(&ulpq->reasm)) != NULL) {
87 event = sctp_skb2event(skb);
88 sctp_ulpevent_free(event);
89 }
90
91}
92
93/* Dispose of a ulpqueue. */
94void sctp_ulpq_free(struct sctp_ulpq *ulpq)
95{
96 sctp_ulpq_flush(ulpq);
97 if (ulpq->malloced)
98 kfree(ulpq);
99}
100
101/* Process an incoming DATA chunk. */
102int sctp_ulpq_tail_data(struct sctp_ulpq *ulpq, struct sctp_chunk *chunk,
Al Virodd0fc662005-10-07 07:46:04 +0100103 gfp_t gfp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104{
105 struct sk_buff_head temp;
106 sctp_data_chunk_t *hdr;
107 struct sctp_ulpevent *event;
108
109 hdr = (sctp_data_chunk_t *) chunk->chunk_hdr;
110
111 /* Create an event from the incoming chunk. */
112 event = sctp_ulpevent_make_rcvmsg(chunk->asoc, chunk, gfp);
113 if (!event)
114 return -ENOMEM;
115
116 /* Do reassembly if needed. */
117 event = sctp_ulpq_reasm(ulpq, event);
118
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));
124
125 event = sctp_ulpq_order(ulpq, event);
126 }
127
David S. Miller8728b832005-08-09 19:25:21 -0700128 /* Send event to the ULP. 'event' is the sctp_ulpevent for
129 * very first SKB on the 'temp' list.
130 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700131 if (event)
132 sctp_ulpq_tail_event(ulpq, event);
133
134 return 0;
135}
136
137/* Add a new event for propagation to the ULP. */
138/* Clear the partial delivery mode for this socket. Note: This
139 * assumes that no association is currently in partial delivery mode.
140 */
141int sctp_clear_pd(struct sock *sk)
142{
143 struct sctp_sock *sp = sctp_sk(sk);
144
145 sp->pd_mode = 0;
146 if (!skb_queue_empty(&sp->pd_lobby)) {
147 struct list_head *list;
148 sctp_skb_list_tail(&sp->pd_lobby, &sk->sk_receive_queue);
149 list = (struct list_head *)&sctp_sk(sk)->pd_lobby;
150 INIT_LIST_HEAD(list);
151 return 1;
152 }
153 return 0;
154}
155
156/* Clear the pd_mode and restart any pending messages waiting for delivery. */
157static int sctp_ulpq_clear_pd(struct sctp_ulpq *ulpq)
158{
159 ulpq->pd_mode = 0;
160 return sctp_clear_pd(ulpq->asoc->base.sk);
161}
162
David S. Miller8728b832005-08-09 19:25:21 -0700163/* If the SKB of 'event' is on a list, it is the first such member
164 * of that list.
165 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166int sctp_ulpq_tail_event(struct sctp_ulpq *ulpq, struct sctp_ulpevent *event)
167{
168 struct sock *sk = ulpq->asoc->base.sk;
David S. Miller8728b832005-08-09 19:25:21 -0700169 struct sk_buff_head *queue, *skb_list;
170 struct sk_buff *skb = sctp_event2skb(event);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700171 int clear_pd = 0;
172
David S. Miller8728b832005-08-09 19:25:21 -0700173 skb_list = (struct sk_buff_head *) skb->prev;
174
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175 /* If the socket is just going to throw this away, do not
176 * even try to deliver it.
177 */
178 if (sock_flag(sk, SOCK_DEAD) || (sk->sk_shutdown & RCV_SHUTDOWN))
179 goto out_free;
180
181 /* Check if the user wishes to receive this event. */
182 if (!sctp_ulpevent_is_enabled(event, &sctp_sk(sk)->subscribe))
183 goto out_free;
184
185 /* If we are in partial delivery mode, post to the lobby until
186 * partial delivery is cleared, unless, of course _this_ is
187 * the association the cause of the partial delivery.
188 */
189
190 if (!sctp_sk(sk)->pd_mode) {
191 queue = &sk->sk_receive_queue;
192 } else if (ulpq->pd_mode) {
193 if (event->msg_flags & MSG_NOTIFICATION)
194 queue = &sctp_sk(sk)->pd_lobby;
195 else {
196 clear_pd = event->msg_flags & MSG_EOR;
197 queue = &sk->sk_receive_queue;
198 }
199 } else
200 queue = &sctp_sk(sk)->pd_lobby;
201
202
203 /* If we are harvesting multiple skbs they will be
204 * collected on a list.
205 */
David S. Miller8728b832005-08-09 19:25:21 -0700206 if (skb_list)
207 sctp_skb_list_tail(skb_list, queue);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700208 else
David S. Miller8728b832005-08-09 19:25:21 -0700209 __skb_queue_tail(queue, skb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700210
211 /* Did we just complete partial delivery and need to get
212 * rolling again? Move pending data to the receive
213 * queue.
214 */
215 if (clear_pd)
216 sctp_ulpq_clear_pd(ulpq);
217
218 if (queue == &sk->sk_receive_queue)
219 sk->sk_data_ready(sk, 0);
220 return 1;
221
222out_free:
David S. Miller8728b832005-08-09 19:25:21 -0700223 if (skb_list)
224 sctp_queue_purge_ulpevents(skb_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700225 else
226 sctp_ulpevent_free(event);
David S. Miller8728b832005-08-09 19:25:21 -0700227
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228 return 0;
229}
230
231/* 2nd Level Abstractions */
232
233/* Helper function to store chunks that need to be reassembled. */
234static inline void sctp_ulpq_store_reasm(struct sctp_ulpq *ulpq,
235 struct sctp_ulpevent *event)
236{
237 struct sk_buff *pos;
238 struct sctp_ulpevent *cevent;
239 __u32 tsn, ctsn;
240
241 tsn = event->tsn;
242
243 /* See if it belongs at the end. */
244 pos = skb_peek_tail(&ulpq->reasm);
245 if (!pos) {
246 __skb_queue_tail(&ulpq->reasm, sctp_event2skb(event));
247 return;
248 }
249
250 /* Short circuit just dropping it at the end. */
251 cevent = sctp_skb2event(pos);
252 ctsn = cevent->tsn;
253 if (TSN_lt(ctsn, tsn)) {
254 __skb_queue_tail(&ulpq->reasm, sctp_event2skb(event));
255 return;
256 }
257
258 /* Find the right place in this list. We store them by TSN. */
259 skb_queue_walk(&ulpq->reasm, pos) {
260 cevent = sctp_skb2event(pos);
261 ctsn = cevent->tsn;
262
263 if (TSN_lt(tsn, ctsn))
264 break;
265 }
266
267 /* Insert before pos. */
268 __skb_insert(sctp_event2skb(event), pos->prev, pos, &ulpq->reasm);
269
270}
271
272/* Helper function to return an event corresponding to the reassembled
273 * datagram.
274 * This routine creates a re-assembled skb given the first and last skb's
275 * as stored in the reassembly queue. The skb's may be non-linear if the sctp
276 * payload was fragmented on the way and ip had to reassemble them.
277 * We add the rest of skb's to the first skb's fraglist.
278 */
David S. Miller8728b832005-08-09 19:25:21 -0700279static struct sctp_ulpevent *sctp_make_reassembled_event(struct sk_buff_head *queue, struct sk_buff *f_frag, struct sk_buff *l_frag)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700280{
281 struct sk_buff *pos;
282 struct sctp_ulpevent *event;
283 struct sk_buff *pnext, *last;
284 struct sk_buff *list = skb_shinfo(f_frag)->frag_list;
285
286 /* Store the pointer to the 2nd skb */
287 if (f_frag == l_frag)
288 pos = NULL;
289 else
290 pos = f_frag->next;
291
292 /* Get the last skb in the f_frag's frag_list if present. */
293 for (last = list; list; last = list, list = list->next);
294
295 /* Add the list of remaining fragments to the first fragments
296 * frag_list.
297 */
298 if (last)
299 last->next = pos;
300 else
301 skb_shinfo(f_frag)->frag_list = pos;
302
303 /* Remove the first fragment from the reassembly queue. */
David S. Miller8728b832005-08-09 19:25:21 -0700304 __skb_unlink(f_frag, queue);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305 while (pos) {
306
307 pnext = pos->next;
308
309 /* Update the len and data_len fields of the first fragment. */
310 f_frag->len += pos->len;
311 f_frag->data_len += pos->len;
312
313 /* Remove the fragment from the reassembly queue. */
David S. Miller8728b832005-08-09 19:25:21 -0700314 __skb_unlink(pos, queue);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315
316 /* Break if we have reached the last fragment. */
317 if (pos == l_frag)
318 break;
319 pos->next = pnext;
320 pos = pnext;
321 };
322
323 event = sctp_skb2event(f_frag);
324 SCTP_INC_STATS(SCTP_MIB_REASMUSRMSGS);
325
326 return event;
327}
328
329
330/* Helper function to check if an incoming chunk has filled up the last
331 * missing fragment in a SCTP datagram and return the corresponding event.
332 */
333static inline struct sctp_ulpevent *sctp_ulpq_retrieve_reassembled(struct sctp_ulpq *ulpq)
334{
335 struct sk_buff *pos;
336 struct sctp_ulpevent *cevent;
337 struct sk_buff *first_frag = NULL;
338 __u32 ctsn, next_tsn;
339 struct sctp_ulpevent *retval = NULL;
340
341 /* Initialized to 0 just to avoid compiler warning message. Will
342 * never be used with this value. It is referenced only after it
343 * is set when we find the first fragment of a message.
344 */
345 next_tsn = 0;
346
347 /* The chunks are held in the reasm queue sorted by TSN.
348 * Walk through the queue sequentially and look for a sequence of
349 * fragmented chunks that complete a datagram.
350 * 'first_frag' and next_tsn are reset when we find a chunk which
351 * is the first fragment of a datagram. Once these 2 fields are set
352 * we expect to find the remaining middle fragments and the last
353 * fragment in order. If not, first_frag is reset to NULL and we
354 * start the next pass when we find another first fragment.
355 */
356 skb_queue_walk(&ulpq->reasm, pos) {
357 cevent = sctp_skb2event(pos);
358 ctsn = cevent->tsn;
359
360 switch (cevent->msg_flags & SCTP_DATA_FRAG_MASK) {
361 case SCTP_DATA_FIRST_FRAG:
362 first_frag = pos;
363 next_tsn = ctsn + 1;
364 break;
365
366 case SCTP_DATA_MIDDLE_FRAG:
367 if ((first_frag) && (ctsn == next_tsn))
368 next_tsn++;
369 else
370 first_frag = NULL;
371 break;
372
373 case SCTP_DATA_LAST_FRAG:
374 if (first_frag && (ctsn == next_tsn))
375 goto found;
376 else
377 first_frag = NULL;
378 break;
379 };
380
381 }
382done:
383 return retval;
384found:
David S. Miller8728b832005-08-09 19:25:21 -0700385 retval = sctp_make_reassembled_event(&ulpq->reasm, first_frag, pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386 if (retval)
387 retval->msg_flags |= MSG_EOR;
388 goto done;
389}
390
391/* Retrieve the next set of fragments of a partial message. */
392static inline struct sctp_ulpevent *sctp_ulpq_retrieve_partial(struct sctp_ulpq *ulpq)
393{
394 struct sk_buff *pos, *last_frag, *first_frag;
395 struct sctp_ulpevent *cevent;
396 __u32 ctsn, next_tsn;
397 int is_last;
398 struct sctp_ulpevent *retval;
399
400 /* The chunks are held in the reasm queue sorted by TSN.
401 * Walk through the queue sequentially and look for the first
402 * sequence of fragmented chunks.
403 */
404
405 if (skb_queue_empty(&ulpq->reasm))
406 return NULL;
407
408 last_frag = first_frag = NULL;
409 retval = NULL;
410 next_tsn = 0;
411 is_last = 0;
412
413 skb_queue_walk(&ulpq->reasm, pos) {
414 cevent = sctp_skb2event(pos);
415 ctsn = cevent->tsn;
416
417 switch (cevent->msg_flags & SCTP_DATA_FRAG_MASK) {
418 case SCTP_DATA_MIDDLE_FRAG:
419 if (!first_frag) {
420 first_frag = pos;
421 next_tsn = ctsn + 1;
422 last_frag = pos;
423 } else if (next_tsn == ctsn)
424 next_tsn++;
425 else
426 goto done;
427 break;
428 case SCTP_DATA_LAST_FRAG:
429 if (!first_frag)
430 first_frag = pos;
431 else if (ctsn != next_tsn)
432 goto done;
433 last_frag = pos;
434 is_last = 1;
435 goto done;
436 default:
437 return NULL;
438 };
439 }
440
441 /* We have the reassembled event. There is no need to look
442 * further.
443 */
444done:
David S. Miller8728b832005-08-09 19:25:21 -0700445 retval = sctp_make_reassembled_event(&ulpq->reasm, first_frag, last_frag);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700446 if (retval && is_last)
447 retval->msg_flags |= MSG_EOR;
448
449 return retval;
450}
451
452
453/* Helper function to reassemble chunks. Hold chunks on the reasm queue that
454 * need reassembling.
455 */
456static struct sctp_ulpevent *sctp_ulpq_reasm(struct sctp_ulpq *ulpq,
457 struct sctp_ulpevent *event)
458{
459 struct sctp_ulpevent *retval = NULL;
460
461 /* Check if this is part of a fragmented message. */
462 if (SCTP_DATA_NOT_FRAG == (event->msg_flags & SCTP_DATA_FRAG_MASK)) {
463 event->msg_flags |= MSG_EOR;
464 return event;
465 }
466
467 sctp_ulpq_store_reasm(ulpq, event);
468 if (!ulpq->pd_mode)
469 retval = sctp_ulpq_retrieve_reassembled(ulpq);
470 else {
471 __u32 ctsn, ctsnap;
472
473 /* Do not even bother unless this is the next tsn to
474 * be delivered.
475 */
476 ctsn = event->tsn;
477 ctsnap = sctp_tsnmap_get_ctsn(&ulpq->asoc->peer.tsn_map);
478 if (TSN_lte(ctsn, ctsnap))
479 retval = sctp_ulpq_retrieve_partial(ulpq);
480 }
481
482 return retval;
483}
484
485/* Retrieve the first part (sequential fragments) for partial delivery. */
486static inline struct sctp_ulpevent *sctp_ulpq_retrieve_first(struct sctp_ulpq *ulpq)
487{
488 struct sk_buff *pos, *last_frag, *first_frag;
489 struct sctp_ulpevent *cevent;
490 __u32 ctsn, next_tsn;
491 struct sctp_ulpevent *retval;
492
493 /* The chunks are held in the reasm queue sorted by TSN.
494 * Walk through the queue sequentially and look for a sequence of
495 * fragmented chunks that start a datagram.
496 */
497
498 if (skb_queue_empty(&ulpq->reasm))
499 return NULL;
500
501 last_frag = first_frag = NULL;
502 retval = NULL;
503 next_tsn = 0;
504
505 skb_queue_walk(&ulpq->reasm, pos) {
506 cevent = sctp_skb2event(pos);
507 ctsn = cevent->tsn;
508
509 switch (cevent->msg_flags & SCTP_DATA_FRAG_MASK) {
510 case SCTP_DATA_FIRST_FRAG:
511 if (!first_frag) {
512 first_frag = pos;
513 next_tsn = ctsn + 1;
514 last_frag = pos;
515 } else
516 goto done;
517 break;
518
519 case SCTP_DATA_MIDDLE_FRAG:
520 if (!first_frag)
521 return NULL;
522 if (ctsn == next_tsn) {
523 next_tsn++;
524 last_frag = pos;
525 } else
526 goto done;
527 break;
528 default:
529 return NULL;
530 };
531 }
532
533 /* We have the reassembled event. There is no need to look
534 * further.
535 */
536done:
David S. Miller8728b832005-08-09 19:25:21 -0700537 retval = sctp_make_reassembled_event(&ulpq->reasm, first_frag, last_frag);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700538 return retval;
539}
540
541/* Helper function to gather skbs that have possibly become
542 * ordered by an an incoming chunk.
543 */
544static inline void sctp_ulpq_retrieve_ordered(struct sctp_ulpq *ulpq,
545 struct sctp_ulpevent *event)
546{
David S. Miller8728b832005-08-09 19:25:21 -0700547 struct sk_buff_head *event_list;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548 struct sk_buff *pos, *tmp;
549 struct sctp_ulpevent *cevent;
550 struct sctp_stream *in;
551 __u16 sid, csid;
552 __u16 ssn, cssn;
553
554 sid = event->stream;
555 ssn = event->ssn;
556 in = &ulpq->asoc->ssnmap->in;
557
David S. Miller8728b832005-08-09 19:25:21 -0700558 event_list = (struct sk_buff_head *) sctp_event2skb(event)->prev;
559
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560 /* We are holding the chunks by stream, by SSN. */
561 sctp_skb_for_each(pos, &ulpq->lobby, tmp) {
562 cevent = (struct sctp_ulpevent *) pos->cb;
563 csid = cevent->stream;
564 cssn = cevent->ssn;
565
566 /* Have we gone too far? */
567 if (csid > sid)
568 break;
569
570 /* Have we not gone far enough? */
571 if (csid < sid)
572 continue;
573
574 if (cssn != sctp_ssn_peek(in, sid))
575 break;
576
577 /* Found it, so mark in the ssnmap. */
578 sctp_ssn_next(in, sid);
579
David S. Miller8728b832005-08-09 19:25:21 -0700580 __skb_unlink(pos, &ulpq->lobby);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581
582 /* Attach all gathered skbs to the event. */
David S. Miller8728b832005-08-09 19:25:21 -0700583 __skb_queue_tail(event_list, pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584 }
585}
586
587/* Helper function to store chunks needing ordering. */
588static inline void sctp_ulpq_store_ordered(struct sctp_ulpq *ulpq,
589 struct sctp_ulpevent *event)
590{
591 struct sk_buff *pos;
592 struct sctp_ulpevent *cevent;
593 __u16 sid, csid;
594 __u16 ssn, cssn;
595
596 pos = skb_peek_tail(&ulpq->lobby);
597 if (!pos) {
598 __skb_queue_tail(&ulpq->lobby, sctp_event2skb(event));
599 return;
600 }
601
602 sid = event->stream;
603 ssn = event->ssn;
604
605 cevent = (struct sctp_ulpevent *) pos->cb;
606 csid = cevent->stream;
607 cssn = cevent->ssn;
608 if (sid > csid) {
609 __skb_queue_tail(&ulpq->lobby, sctp_event2skb(event));
610 return;
611 }
612
613 if ((sid == csid) && SSN_lt(cssn, ssn)) {
614 __skb_queue_tail(&ulpq->lobby, sctp_event2skb(event));
615 return;
616 }
617
618 /* Find the right place in this list. We store them by
619 * stream ID and then by SSN.
620 */
621 skb_queue_walk(&ulpq->lobby, pos) {
622 cevent = (struct sctp_ulpevent *) pos->cb;
623 csid = cevent->stream;
624 cssn = cevent->ssn;
625
626 if (csid > sid)
627 break;
628 if (csid == sid && SSN_lt(ssn, cssn))
629 break;
630 }
631
632
633 /* Insert before pos. */
634 __skb_insert(sctp_event2skb(event), pos->prev, pos, &ulpq->lobby);
635
636}
637
638static struct sctp_ulpevent *sctp_ulpq_order(struct sctp_ulpq *ulpq,
David S. Miller8728b832005-08-09 19:25:21 -0700639 struct sctp_ulpevent *event)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700640{
641 __u16 sid, ssn;
642 struct sctp_stream *in;
643
644 /* Check if this message needs ordering. */
645 if (SCTP_DATA_UNORDERED & event->msg_flags)
646 return event;
647
648 /* Note: The stream ID must be verified before this routine. */
649 sid = event->stream;
650 ssn = event->ssn;
651 in = &ulpq->asoc->ssnmap->in;
652
653 /* Is this the expected SSN for this stream ID? */
654 if (ssn != sctp_ssn_peek(in, sid)) {
655 /* We've received something out of order, so find where it
656 * needs to be placed. We order by stream and then by SSN.
657 */
658 sctp_ulpq_store_ordered(ulpq, event);
659 return NULL;
660 }
661
662 /* Mark that the next chunk has been found. */
663 sctp_ssn_next(in, sid);
664
665 /* Go find any other chunks that were waiting for
666 * ordering.
667 */
668 sctp_ulpq_retrieve_ordered(ulpq, event);
669
670 return event;
671}
672
673/* Helper function to gather skbs that have possibly become
674 * ordered by forward tsn skipping their dependencies.
675 */
676static inline void sctp_ulpq_reap_ordered(struct sctp_ulpq *ulpq)
677{
678 struct sk_buff *pos, *tmp;
679 struct sctp_ulpevent *cevent;
David S. Miller8728b832005-08-09 19:25:21 -0700680 struct sctp_ulpevent *event;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700681 struct sctp_stream *in;
682 struct sk_buff_head temp;
683 __u16 csid, cssn;
684
685 in = &ulpq->asoc->ssnmap->in;
686
687 /* We are holding the chunks by stream, by SSN. */
David S. Miller8728b832005-08-09 19:25:21 -0700688 skb_queue_head_init(&temp);
689 event = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700690 sctp_skb_for_each(pos, &ulpq->lobby, tmp) {
691 cevent = (struct sctp_ulpevent *) pos->cb;
692 csid = cevent->stream;
693 cssn = cevent->ssn;
694
695 if (cssn != sctp_ssn_peek(in, csid))
696 break;
697
698 /* Found it, so mark in the ssnmap. */
699 sctp_ssn_next(in, csid);
700
David S. Miller8728b832005-08-09 19:25:21 -0700701 __skb_unlink(pos, &ulpq->lobby);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700702 if (!event) {
703 /* Create a temporary list to collect chunks on. */
704 event = sctp_skb2event(pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705 __skb_queue_tail(&temp, sctp_event2skb(event));
706 } else {
707 /* Attach all gathered skbs to the event. */
David S. Miller8728b832005-08-09 19:25:21 -0700708 __skb_queue_tail(&temp, pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700709 }
710 }
711
David S. Miller8728b832005-08-09 19:25:21 -0700712 /* Send event to the ULP. 'event' is the sctp_ulpevent for
713 * very first SKB on the 'temp' list.
714 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700715 if (event)
716 sctp_ulpq_tail_event(ulpq, event);
717}
718
719/* Skip over an SSN. */
720void sctp_ulpq_skip(struct sctp_ulpq *ulpq, __u16 sid, __u16 ssn)
721{
722 struct sctp_stream *in;
723
724 /* Note: The stream ID must be verified before this routine. */
725 in = &ulpq->asoc->ssnmap->in;
726
727 /* Is this an old SSN? If so ignore. */
728 if (SSN_lt(ssn, sctp_ssn_peek(in, sid)))
729 return;
730
731 /* Mark that we are no longer expecting this SSN or lower. */
732 sctp_ssn_skip(in, sid, ssn);
733
734 /* Go find any other chunks that were waiting for
735 * ordering and deliver them if needed.
736 */
737 sctp_ulpq_reap_ordered(ulpq);
738 return;
739}
740
741/* Renege 'needed' bytes from the ordering queue. */
742static __u16 sctp_ulpq_renege_order(struct sctp_ulpq *ulpq, __u16 needed)
743{
744 __u16 freed = 0;
745 __u32 tsn;
746 struct sk_buff *skb;
747 struct sctp_ulpevent *event;
748 struct sctp_tsnmap *tsnmap;
749
750 tsnmap = &ulpq->asoc->peer.tsn_map;
751
752 while ((skb = __skb_dequeue_tail(&ulpq->lobby)) != NULL) {
753 freed += skb_headlen(skb);
754 event = sctp_skb2event(skb);
755 tsn = event->tsn;
756
757 sctp_ulpevent_free(event);
758 sctp_tsnmap_renege(tsnmap, tsn);
759 if (freed >= needed)
760 return freed;
761 }
762
763 return freed;
764}
765
766/* Renege 'needed' bytes from the reassembly queue. */
767static __u16 sctp_ulpq_renege_frags(struct sctp_ulpq *ulpq, __u16 needed)
768{
769 __u16 freed = 0;
770 __u32 tsn;
771 struct sk_buff *skb;
772 struct sctp_ulpevent *event;
773 struct sctp_tsnmap *tsnmap;
774
775 tsnmap = &ulpq->asoc->peer.tsn_map;
776
777 /* Walk backwards through the list, reneges the newest tsns. */
778 while ((skb = __skb_dequeue_tail(&ulpq->reasm)) != NULL) {
779 freed += skb_headlen(skb);
780 event = sctp_skb2event(skb);
781 tsn = event->tsn;
782
783 sctp_ulpevent_free(event);
784 sctp_tsnmap_renege(tsnmap, tsn);
785 if (freed >= needed)
786 return freed;
787 }
788
789 return freed;
790}
791
792/* Partial deliver the first message as there is pressure on rwnd. */
793void sctp_ulpq_partial_delivery(struct sctp_ulpq *ulpq,
Alexey Dobriyan3182cd842005-07-11 20:57:47 -0700794 struct sctp_chunk *chunk,
Al Virodd0fc662005-10-07 07:46:04 +0100795 gfp_t gfp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700796{
797 struct sctp_ulpevent *event;
798 struct sctp_association *asoc;
799
800 asoc = ulpq->asoc;
801
802 /* Are we already in partial delivery mode? */
803 if (!sctp_sk(asoc->base.sk)->pd_mode) {
804
805 /* Is partial delivery possible? */
806 event = sctp_ulpq_retrieve_first(ulpq);
807 /* Send event to the ULP. */
808 if (event) {
809 sctp_ulpq_tail_event(ulpq, event);
810 sctp_sk(asoc->base.sk)->pd_mode = 1;
811 ulpq->pd_mode = 1;
812 return;
813 }
814 }
815}
816
817/* Renege some packets to make room for an incoming chunk. */
818void sctp_ulpq_renege(struct sctp_ulpq *ulpq, struct sctp_chunk *chunk,
Al Virodd0fc662005-10-07 07:46:04 +0100819 gfp_t gfp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700820{
821 struct sctp_association *asoc;
822 __u16 needed, freed;
823
824 asoc = ulpq->asoc;
825
826 if (chunk) {
827 needed = ntohs(chunk->chunk_hdr->length);
828 needed -= sizeof(sctp_data_chunk_t);
829 } else
830 needed = SCTP_DEFAULT_MAXWINDOW;
831
832 freed = 0;
833
834 if (skb_queue_empty(&asoc->base.sk->sk_receive_queue)) {
835 freed = sctp_ulpq_renege_order(ulpq, needed);
836 if (freed < needed) {
837 freed += sctp_ulpq_renege_frags(ulpq, needed - freed);
838 }
839 }
840 /* If able to free enough room, accept this chunk. */
841 if (chunk && (freed >= needed)) {
842 __u32 tsn;
843 tsn = ntohl(chunk->subh.data_hdr->tsn);
844 sctp_tsnmap_mark(&asoc->peer.tsn_map, tsn);
845 sctp_ulpq_tail_data(ulpq, chunk, gfp);
846
847 sctp_ulpq_partial_delivery(ulpq, chunk, gfp);
848 }
849
850 return;
851}
852
853
854
855/* Notify the application if an association is aborted and in
856 * partial delivery mode. Send up any pending received messages.
857 */
Al Virodd0fc662005-10-07 07:46:04 +0100858void sctp_ulpq_abort_pd(struct sctp_ulpq *ulpq, gfp_t gfp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700859{
860 struct sctp_ulpevent *ev = NULL;
861 struct sock *sk;
862
863 if (!ulpq->pd_mode)
864 return;
865
866 sk = ulpq->asoc->base.sk;
867 if (sctp_ulpevent_type_enabled(SCTP_PARTIAL_DELIVERY_EVENT,
868 &sctp_sk(sk)->subscribe))
869 ev = sctp_ulpevent_make_pdapi(ulpq->asoc,
870 SCTP_PARTIAL_DELIVERY_ABORTED,
871 gfp);
872 if (ev)
873 __skb_queue_tail(&sk->sk_receive_queue, sctp_event2skb(ev));
874
875 /* If there is data waiting, send it up the socket now. */
876 if (sctp_ulpq_clear_pd(ulpq) || ev)
877 sk->sk_data_ready(sk, 0);
878}