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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;
Vladislav Yasevich672e7cc2006-05-05 17:03:49 -0700282 struct sk_buff *new = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700283 struct sctp_ulpevent *event;
284 struct sk_buff *pnext, *last;
285 struct sk_buff *list = skb_shinfo(f_frag)->frag_list;
286
287 /* Store the pointer to the 2nd skb */
288 if (f_frag == l_frag)
289 pos = NULL;
290 else
291 pos = f_frag->next;
292
293 /* Get the last skb in the f_frag's frag_list if present. */
294 for (last = list; list; last = list, list = list->next);
295
296 /* Add the list of remaining fragments to the first fragments
297 * frag_list.
298 */
299 if (last)
300 last->next = pos;
Vladislav Yasevich672e7cc2006-05-05 17:03:49 -0700301 else {
302 if (skb_cloned(f_frag)) {
303 /* This is a cloned skb, we can't just modify
304 * the frag_list. We need a new skb to do that.
305 * Instead of calling skb_unshare(), we'll do it
306 * ourselves since we need to delay the free.
307 */
308 new = skb_copy(f_frag, GFP_ATOMIC);
309 if (!new)
310 return NULL; /* try again later */
311
312 new->sk = f_frag->sk;
313
314 skb_shinfo(new)->frag_list = pos;
315 } else
316 skb_shinfo(f_frag)->frag_list = pos;
317 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318
319 /* Remove the first fragment from the reassembly queue. */
David S. Miller8728b832005-08-09 19:25:21 -0700320 __skb_unlink(f_frag, queue);
Vladislav Yasevich672e7cc2006-05-05 17:03:49 -0700321
322 /* if we did unshare, then free the old skb and re-assign */
323 if (new) {
324 kfree_skb(f_frag);
325 f_frag = new;
326 }
327
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328 while (pos) {
329
330 pnext = pos->next;
331
332 /* Update the len and data_len fields of the first fragment. */
333 f_frag->len += pos->len;
334 f_frag->data_len += pos->len;
335
336 /* Remove the fragment from the reassembly queue. */
David S. Miller8728b832005-08-09 19:25:21 -0700337 __skb_unlink(pos, queue);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700338
339 /* Break if we have reached the last fragment. */
340 if (pos == l_frag)
341 break;
342 pos->next = pnext;
343 pos = pnext;
344 };
345
346 event = sctp_skb2event(f_frag);
347 SCTP_INC_STATS(SCTP_MIB_REASMUSRMSGS);
348
349 return event;
350}
351
352
353/* Helper function to check if an incoming chunk has filled up the last
354 * missing fragment in a SCTP datagram and return the corresponding event.
355 */
356static inline struct sctp_ulpevent *sctp_ulpq_retrieve_reassembled(struct sctp_ulpq *ulpq)
357{
358 struct sk_buff *pos;
359 struct sctp_ulpevent *cevent;
360 struct sk_buff *first_frag = NULL;
361 __u32 ctsn, next_tsn;
362 struct sctp_ulpevent *retval = NULL;
363
364 /* Initialized to 0 just to avoid compiler warning message. Will
365 * never be used with this value. It is referenced only after it
366 * is set when we find the first fragment of a message.
367 */
368 next_tsn = 0;
369
370 /* The chunks are held in the reasm queue sorted by TSN.
371 * Walk through the queue sequentially and look for a sequence of
372 * fragmented chunks that complete a datagram.
373 * 'first_frag' and next_tsn are reset when we find a chunk which
374 * is the first fragment of a datagram. Once these 2 fields are set
375 * we expect to find the remaining middle fragments and the last
376 * fragment in order. If not, first_frag is reset to NULL and we
377 * start the next pass when we find another first fragment.
378 */
379 skb_queue_walk(&ulpq->reasm, pos) {
380 cevent = sctp_skb2event(pos);
381 ctsn = cevent->tsn;
382
383 switch (cevent->msg_flags & SCTP_DATA_FRAG_MASK) {
384 case SCTP_DATA_FIRST_FRAG:
385 first_frag = pos;
386 next_tsn = ctsn + 1;
387 break;
388
389 case SCTP_DATA_MIDDLE_FRAG:
390 if ((first_frag) && (ctsn == next_tsn))
391 next_tsn++;
392 else
393 first_frag = NULL;
394 break;
395
396 case SCTP_DATA_LAST_FRAG:
397 if (first_frag && (ctsn == next_tsn))
398 goto found;
399 else
400 first_frag = NULL;
401 break;
402 };
403
404 }
405done:
406 return retval;
407found:
David S. Miller8728b832005-08-09 19:25:21 -0700408 retval = sctp_make_reassembled_event(&ulpq->reasm, first_frag, pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409 if (retval)
410 retval->msg_flags |= MSG_EOR;
411 goto done;
412}
413
414/* Retrieve the next set of fragments of a partial message. */
415static inline struct sctp_ulpevent *sctp_ulpq_retrieve_partial(struct sctp_ulpq *ulpq)
416{
417 struct sk_buff *pos, *last_frag, *first_frag;
418 struct sctp_ulpevent *cevent;
419 __u32 ctsn, next_tsn;
420 int is_last;
421 struct sctp_ulpevent *retval;
422
423 /* The chunks are held in the reasm queue sorted by TSN.
424 * Walk through the queue sequentially and look for the first
425 * sequence of fragmented chunks.
426 */
427
428 if (skb_queue_empty(&ulpq->reasm))
429 return NULL;
430
431 last_frag = first_frag = NULL;
432 retval = NULL;
433 next_tsn = 0;
434 is_last = 0;
435
436 skb_queue_walk(&ulpq->reasm, pos) {
437 cevent = sctp_skb2event(pos);
438 ctsn = cevent->tsn;
439
440 switch (cevent->msg_flags & SCTP_DATA_FRAG_MASK) {
441 case SCTP_DATA_MIDDLE_FRAG:
442 if (!first_frag) {
443 first_frag = pos;
444 next_tsn = ctsn + 1;
445 last_frag = pos;
446 } else if (next_tsn == ctsn)
447 next_tsn++;
448 else
449 goto done;
450 break;
451 case SCTP_DATA_LAST_FRAG:
452 if (!first_frag)
453 first_frag = pos;
454 else if (ctsn != next_tsn)
455 goto done;
456 last_frag = pos;
457 is_last = 1;
458 goto done;
459 default:
460 return NULL;
461 };
462 }
463
464 /* We have the reassembled event. There is no need to look
465 * further.
466 */
467done:
David S. Miller8728b832005-08-09 19:25:21 -0700468 retval = sctp_make_reassembled_event(&ulpq->reasm, first_frag, last_frag);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469 if (retval && is_last)
470 retval->msg_flags |= MSG_EOR;
471
472 return retval;
473}
474
475
476/* Helper function to reassemble chunks. Hold chunks on the reasm queue that
477 * need reassembling.
478 */
479static struct sctp_ulpevent *sctp_ulpq_reasm(struct sctp_ulpq *ulpq,
480 struct sctp_ulpevent *event)
481{
482 struct sctp_ulpevent *retval = NULL;
483
484 /* Check if this is part of a fragmented message. */
485 if (SCTP_DATA_NOT_FRAG == (event->msg_flags & SCTP_DATA_FRAG_MASK)) {
486 event->msg_flags |= MSG_EOR;
487 return event;
488 }
489
490 sctp_ulpq_store_reasm(ulpq, event);
491 if (!ulpq->pd_mode)
492 retval = sctp_ulpq_retrieve_reassembled(ulpq);
493 else {
494 __u32 ctsn, ctsnap;
495
496 /* Do not even bother unless this is the next tsn to
497 * be delivered.
498 */
499 ctsn = event->tsn;
500 ctsnap = sctp_tsnmap_get_ctsn(&ulpq->asoc->peer.tsn_map);
501 if (TSN_lte(ctsn, ctsnap))
502 retval = sctp_ulpq_retrieve_partial(ulpq);
503 }
504
505 return retval;
506}
507
508/* Retrieve the first part (sequential fragments) for partial delivery. */
509static inline struct sctp_ulpevent *sctp_ulpq_retrieve_first(struct sctp_ulpq *ulpq)
510{
511 struct sk_buff *pos, *last_frag, *first_frag;
512 struct sctp_ulpevent *cevent;
513 __u32 ctsn, next_tsn;
514 struct sctp_ulpevent *retval;
515
516 /* The chunks are held in the reasm queue sorted by TSN.
517 * Walk through the queue sequentially and look for a sequence of
518 * fragmented chunks that start a datagram.
519 */
520
521 if (skb_queue_empty(&ulpq->reasm))
522 return NULL;
523
524 last_frag = first_frag = NULL;
525 retval = NULL;
526 next_tsn = 0;
527
528 skb_queue_walk(&ulpq->reasm, pos) {
529 cevent = sctp_skb2event(pos);
530 ctsn = cevent->tsn;
531
532 switch (cevent->msg_flags & SCTP_DATA_FRAG_MASK) {
533 case SCTP_DATA_FIRST_FRAG:
534 if (!first_frag) {
535 first_frag = pos;
536 next_tsn = ctsn + 1;
537 last_frag = pos;
538 } else
539 goto done;
540 break;
541
542 case SCTP_DATA_MIDDLE_FRAG:
543 if (!first_frag)
544 return NULL;
545 if (ctsn == next_tsn) {
546 next_tsn++;
547 last_frag = pos;
548 } else
549 goto done;
550 break;
551 default:
552 return NULL;
553 };
554 }
555
556 /* We have the reassembled event. There is no need to look
557 * further.
558 */
559done:
David S. Miller8728b832005-08-09 19:25:21 -0700560 retval = sctp_make_reassembled_event(&ulpq->reasm, first_frag, last_frag);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700561 return retval;
562}
563
564/* Helper function to gather skbs that have possibly become
565 * ordered by an an incoming chunk.
566 */
567static inline void sctp_ulpq_retrieve_ordered(struct sctp_ulpq *ulpq,
568 struct sctp_ulpevent *event)
569{
David S. Miller8728b832005-08-09 19:25:21 -0700570 struct sk_buff_head *event_list;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700571 struct sk_buff *pos, *tmp;
572 struct sctp_ulpevent *cevent;
573 struct sctp_stream *in;
574 __u16 sid, csid;
575 __u16 ssn, cssn;
576
577 sid = event->stream;
578 ssn = event->ssn;
579 in = &ulpq->asoc->ssnmap->in;
580
David S. Miller8728b832005-08-09 19:25:21 -0700581 event_list = (struct sk_buff_head *) sctp_event2skb(event)->prev;
582
Linus Torvalds1da177e2005-04-16 15:20:36 -0700583 /* We are holding the chunks by stream, by SSN. */
584 sctp_skb_for_each(pos, &ulpq->lobby, tmp) {
585 cevent = (struct sctp_ulpevent *) pos->cb;
586 csid = cevent->stream;
587 cssn = cevent->ssn;
588
589 /* Have we gone too far? */
590 if (csid > sid)
591 break;
592
593 /* Have we not gone far enough? */
594 if (csid < sid)
595 continue;
596
597 if (cssn != sctp_ssn_peek(in, sid))
598 break;
599
600 /* Found it, so mark in the ssnmap. */
601 sctp_ssn_next(in, sid);
602
David S. Miller8728b832005-08-09 19:25:21 -0700603 __skb_unlink(pos, &ulpq->lobby);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700604
605 /* Attach all gathered skbs to the event. */
David S. Miller8728b832005-08-09 19:25:21 -0700606 __skb_queue_tail(event_list, pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700607 }
608}
609
610/* Helper function to store chunks needing ordering. */
611static inline void sctp_ulpq_store_ordered(struct sctp_ulpq *ulpq,
612 struct sctp_ulpevent *event)
613{
614 struct sk_buff *pos;
615 struct sctp_ulpevent *cevent;
616 __u16 sid, csid;
617 __u16 ssn, cssn;
618
619 pos = skb_peek_tail(&ulpq->lobby);
620 if (!pos) {
621 __skb_queue_tail(&ulpq->lobby, sctp_event2skb(event));
622 return;
623 }
624
625 sid = event->stream;
626 ssn = event->ssn;
627
628 cevent = (struct sctp_ulpevent *) pos->cb;
629 csid = cevent->stream;
630 cssn = cevent->ssn;
631 if (sid > csid) {
632 __skb_queue_tail(&ulpq->lobby, sctp_event2skb(event));
633 return;
634 }
635
636 if ((sid == csid) && SSN_lt(cssn, ssn)) {
637 __skb_queue_tail(&ulpq->lobby, sctp_event2skb(event));
638 return;
639 }
640
641 /* Find the right place in this list. We store them by
642 * stream ID and then by SSN.
643 */
644 skb_queue_walk(&ulpq->lobby, pos) {
645 cevent = (struct sctp_ulpevent *) pos->cb;
646 csid = cevent->stream;
647 cssn = cevent->ssn;
648
649 if (csid > sid)
650 break;
651 if (csid == sid && SSN_lt(ssn, cssn))
652 break;
653 }
654
655
656 /* Insert before pos. */
657 __skb_insert(sctp_event2skb(event), pos->prev, pos, &ulpq->lobby);
658
659}
660
661static struct sctp_ulpevent *sctp_ulpq_order(struct sctp_ulpq *ulpq,
David S. Miller8728b832005-08-09 19:25:21 -0700662 struct sctp_ulpevent *event)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700663{
664 __u16 sid, ssn;
665 struct sctp_stream *in;
666
667 /* Check if this message needs ordering. */
668 if (SCTP_DATA_UNORDERED & event->msg_flags)
669 return event;
670
671 /* Note: The stream ID must be verified before this routine. */
672 sid = event->stream;
673 ssn = event->ssn;
674 in = &ulpq->asoc->ssnmap->in;
675
676 /* Is this the expected SSN for this stream ID? */
677 if (ssn != sctp_ssn_peek(in, sid)) {
678 /* We've received something out of order, so find where it
679 * needs to be placed. We order by stream and then by SSN.
680 */
681 sctp_ulpq_store_ordered(ulpq, event);
682 return NULL;
683 }
684
685 /* Mark that the next chunk has been found. */
686 sctp_ssn_next(in, sid);
687
688 /* Go find any other chunks that were waiting for
689 * ordering.
690 */
691 sctp_ulpq_retrieve_ordered(ulpq, event);
692
693 return event;
694}
695
696/* Helper function to gather skbs that have possibly become
697 * ordered by forward tsn skipping their dependencies.
698 */
699static inline void sctp_ulpq_reap_ordered(struct sctp_ulpq *ulpq)
700{
701 struct sk_buff *pos, *tmp;
702 struct sctp_ulpevent *cevent;
David S. Miller8728b832005-08-09 19:25:21 -0700703 struct sctp_ulpevent *event;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700704 struct sctp_stream *in;
705 struct sk_buff_head temp;
706 __u16 csid, cssn;
707
708 in = &ulpq->asoc->ssnmap->in;
709
710 /* We are holding the chunks by stream, by SSN. */
David S. Miller8728b832005-08-09 19:25:21 -0700711 skb_queue_head_init(&temp);
712 event = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700713 sctp_skb_for_each(pos, &ulpq->lobby, tmp) {
714 cevent = (struct sctp_ulpevent *) pos->cb;
715 csid = cevent->stream;
716 cssn = cevent->ssn;
717
718 if (cssn != sctp_ssn_peek(in, csid))
719 break;
720
721 /* Found it, so mark in the ssnmap. */
722 sctp_ssn_next(in, csid);
723
David S. Miller8728b832005-08-09 19:25:21 -0700724 __skb_unlink(pos, &ulpq->lobby);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700725 if (!event) {
726 /* Create a temporary list to collect chunks on. */
727 event = sctp_skb2event(pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700728 __skb_queue_tail(&temp, sctp_event2skb(event));
729 } else {
730 /* Attach all gathered skbs to the event. */
David S. Miller8728b832005-08-09 19:25:21 -0700731 __skb_queue_tail(&temp, pos);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700732 }
733 }
734
David S. Miller8728b832005-08-09 19:25:21 -0700735 /* Send event to the ULP. 'event' is the sctp_ulpevent for
736 * very first SKB on the 'temp' list.
737 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700738 if (event)
739 sctp_ulpq_tail_event(ulpq, event);
740}
741
742/* Skip over an SSN. */
743void sctp_ulpq_skip(struct sctp_ulpq *ulpq, __u16 sid, __u16 ssn)
744{
745 struct sctp_stream *in;
746
747 /* Note: The stream ID must be verified before this routine. */
748 in = &ulpq->asoc->ssnmap->in;
749
750 /* Is this an old SSN? If so ignore. */
751 if (SSN_lt(ssn, sctp_ssn_peek(in, sid)))
752 return;
753
754 /* Mark that we are no longer expecting this SSN or lower. */
755 sctp_ssn_skip(in, sid, ssn);
756
757 /* Go find any other chunks that were waiting for
758 * ordering and deliver them if needed.
759 */
760 sctp_ulpq_reap_ordered(ulpq);
761 return;
762}
763
764/* Renege 'needed' bytes from the ordering queue. */
765static __u16 sctp_ulpq_renege_order(struct sctp_ulpq *ulpq, __u16 needed)
766{
767 __u16 freed = 0;
768 __u32 tsn;
769 struct sk_buff *skb;
770 struct sctp_ulpevent *event;
771 struct sctp_tsnmap *tsnmap;
772
773 tsnmap = &ulpq->asoc->peer.tsn_map;
774
775 while ((skb = __skb_dequeue_tail(&ulpq->lobby)) != NULL) {
776 freed += skb_headlen(skb);
777 event = sctp_skb2event(skb);
778 tsn = event->tsn;
779
780 sctp_ulpevent_free(event);
781 sctp_tsnmap_renege(tsnmap, tsn);
782 if (freed >= needed)
783 return freed;
784 }
785
786 return freed;
787}
788
789/* Renege 'needed' bytes from the reassembly queue. */
790static __u16 sctp_ulpq_renege_frags(struct sctp_ulpq *ulpq, __u16 needed)
791{
792 __u16 freed = 0;
793 __u32 tsn;
794 struct sk_buff *skb;
795 struct sctp_ulpevent *event;
796 struct sctp_tsnmap *tsnmap;
797
798 tsnmap = &ulpq->asoc->peer.tsn_map;
799
800 /* Walk backwards through the list, reneges the newest tsns. */
801 while ((skb = __skb_dequeue_tail(&ulpq->reasm)) != NULL) {
802 freed += skb_headlen(skb);
803 event = sctp_skb2event(skb);
804 tsn = event->tsn;
805
806 sctp_ulpevent_free(event);
807 sctp_tsnmap_renege(tsnmap, tsn);
808 if (freed >= needed)
809 return freed;
810 }
811
812 return freed;
813}
814
815/* Partial deliver the first message as there is pressure on rwnd. */
816void sctp_ulpq_partial_delivery(struct sctp_ulpq *ulpq,
Alexey Dobriyan3182cd82005-07-11 20:57:47 -0700817 struct sctp_chunk *chunk,
Al Virodd0fc662005-10-07 07:46:04 +0100818 gfp_t gfp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700819{
820 struct sctp_ulpevent *event;
821 struct sctp_association *asoc;
822
823 asoc = ulpq->asoc;
824
825 /* Are we already in partial delivery mode? */
826 if (!sctp_sk(asoc->base.sk)->pd_mode) {
827
828 /* Is partial delivery possible? */
829 event = sctp_ulpq_retrieve_first(ulpq);
830 /* Send event to the ULP. */
831 if (event) {
832 sctp_ulpq_tail_event(ulpq, event);
833 sctp_sk(asoc->base.sk)->pd_mode = 1;
834 ulpq->pd_mode = 1;
835 return;
836 }
837 }
838}
839
840/* Renege some packets to make room for an incoming chunk. */
841void sctp_ulpq_renege(struct sctp_ulpq *ulpq, struct sctp_chunk *chunk,
Al Virodd0fc662005-10-07 07:46:04 +0100842 gfp_t gfp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700843{
844 struct sctp_association *asoc;
845 __u16 needed, freed;
846
847 asoc = ulpq->asoc;
848
849 if (chunk) {
850 needed = ntohs(chunk->chunk_hdr->length);
851 needed -= sizeof(sctp_data_chunk_t);
852 } else
853 needed = SCTP_DEFAULT_MAXWINDOW;
854
855 freed = 0;
856
857 if (skb_queue_empty(&asoc->base.sk->sk_receive_queue)) {
858 freed = sctp_ulpq_renege_order(ulpq, needed);
859 if (freed < needed) {
860 freed += sctp_ulpq_renege_frags(ulpq, needed - freed);
861 }
862 }
863 /* If able to free enough room, accept this chunk. */
864 if (chunk && (freed >= needed)) {
865 __u32 tsn;
866 tsn = ntohl(chunk->subh.data_hdr->tsn);
867 sctp_tsnmap_mark(&asoc->peer.tsn_map, tsn);
868 sctp_ulpq_tail_data(ulpq, chunk, gfp);
869
870 sctp_ulpq_partial_delivery(ulpq, chunk, gfp);
871 }
872
873 return;
874}
875
876
877
878/* Notify the application if an association is aborted and in
879 * partial delivery mode. Send up any pending received messages.
880 */
Al Virodd0fc662005-10-07 07:46:04 +0100881void sctp_ulpq_abort_pd(struct sctp_ulpq *ulpq, gfp_t gfp)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700882{
883 struct sctp_ulpevent *ev = NULL;
884 struct sock *sk;
885
886 if (!ulpq->pd_mode)
887 return;
888
889 sk = ulpq->asoc->base.sk;
890 if (sctp_ulpevent_type_enabled(SCTP_PARTIAL_DELIVERY_EVENT,
891 &sctp_sk(sk)->subscribe))
892 ev = sctp_ulpevent_make_pdapi(ulpq->asoc,
893 SCTP_PARTIAL_DELIVERY_ABORTED,
894 gfp);
895 if (ev)
896 __skb_queue_tail(&sk->sk_receive_queue, sctp_event2skb(ev));
897
898 /* If there is data waiting, send it up the socket now. */
899 if (sctp_ulpq_clear_pd(ulpq) || ev)
900 sk->sk_data_ready(sk, 0);
901}