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1da177e4 LT |
1 | /* 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. */ | |
52 | static struct sctp_ulpevent * sctp_ulpq_reasm(struct sctp_ulpq *ulpq, | |
8728b834 | 53 | struct sctp_ulpevent *); |
1da177e4 | 54 | static struct sctp_ulpevent * sctp_ulpq_order(struct sctp_ulpq *, |
8728b834 | 55 | struct sctp_ulpevent *); |
1da177e4 LT |
56 | |
57 | /* 1st Level Abstractions */ | |
58 | ||
59 | /* Initialize a ULP queue from a block of memory. */ | |
60 | struct 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. */ | |
0b58a811 | 76 | void sctp_ulpq_flush(struct sctp_ulpq *ulpq) |
1da177e4 LT |
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. */ | |
94 | void 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. */ | |
102 | int sctp_ulpq_tail_data(struct sctp_ulpq *ulpq, struct sctp_chunk *chunk, | |
dd0fc66f | 103 | gfp_t gfp) |
1da177e4 LT |
104 | { |
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 | ||
8728b834 DM |
128 | /* Send event to the ULP. 'event' is the sctp_ulpevent for |
129 | * very first SKB on the 'temp' list. | |
130 | */ | |
1da177e4 LT |
131 | 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 | */ | |
b6e1331f | 141 | int sctp_clear_pd(struct sock *sk, struct sctp_association *asoc) |
1da177e4 LT |
142 | { |
143 | struct sctp_sock *sp = sctp_sk(sk); | |
144 | ||
b6e1331f VY |
145 | if (atomic_dec_and_test(&sp->pd_mode)) { |
146 | /* This means there are no other associations in PD, so | |
147 | * we can go ahead and clear out the lobby in one shot | |
148 | */ | |
149 | if (!skb_queue_empty(&sp->pd_lobby)) { | |
150 | struct list_head *list; | |
151 | sctp_skb_list_tail(&sp->pd_lobby, &sk->sk_receive_queue); | |
152 | list = (struct list_head *)&sctp_sk(sk)->pd_lobby; | |
153 | INIT_LIST_HEAD(list); | |
154 | return 1; | |
155 | } | |
156 | } else { | |
157 | /* There are other associations in PD, so we only need to | |
158 | * pull stuff out of the lobby that belongs to the | |
159 | * associations that is exiting PD (all of its notifications | |
160 | * are posted here). | |
161 | */ | |
162 | if (!skb_queue_empty(&sp->pd_lobby) && asoc) { | |
163 | struct sk_buff *skb, *tmp; | |
164 | struct sctp_ulpevent *event; | |
165 | ||
166 | sctp_skb_for_each(skb, &sp->pd_lobby, tmp) { | |
167 | event = sctp_skb2event(skb); | |
168 | if (event->asoc == asoc) { | |
169 | __skb_unlink(skb, &sp->pd_lobby); | |
170 | __skb_queue_tail(&sk->sk_receive_queue, | |
171 | skb); | |
172 | } | |
173 | } | |
174 | } | |
1da177e4 | 175 | } |
b6e1331f | 176 | |
1da177e4 LT |
177 | return 0; |
178 | } | |
179 | ||
180 | /* Clear the pd_mode and restart any pending messages waiting for delivery. */ | |
181 | static int sctp_ulpq_clear_pd(struct sctp_ulpq *ulpq) | |
182 | { | |
183 | ulpq->pd_mode = 0; | |
b6e1331f | 184 | return sctp_clear_pd(ulpq->asoc->base.sk, ulpq->asoc); |
1da177e4 LT |
185 | } |
186 | ||
8728b834 DM |
187 | /* If the SKB of 'event' is on a list, it is the first such member |
188 | * of that list. | |
189 | */ | |
1da177e4 LT |
190 | int sctp_ulpq_tail_event(struct sctp_ulpq *ulpq, struct sctp_ulpevent *event) |
191 | { | |
192 | struct sock *sk = ulpq->asoc->base.sk; | |
8728b834 DM |
193 | struct sk_buff_head *queue, *skb_list; |
194 | struct sk_buff *skb = sctp_event2skb(event); | |
1da177e4 LT |
195 | int clear_pd = 0; |
196 | ||
8728b834 DM |
197 | skb_list = (struct sk_buff_head *) skb->prev; |
198 | ||
1da177e4 LT |
199 | /* If the socket is just going to throw this away, do not |
200 | * even try to deliver it. | |
201 | */ | |
202 | if (sock_flag(sk, SOCK_DEAD) || (sk->sk_shutdown & RCV_SHUTDOWN)) | |
203 | goto out_free; | |
204 | ||
205 | /* Check if the user wishes to receive this event. */ | |
206 | if (!sctp_ulpevent_is_enabled(event, &sctp_sk(sk)->subscribe)) | |
207 | goto out_free; | |
208 | ||
209 | /* If we are in partial delivery mode, post to the lobby until | |
210 | * partial delivery is cleared, unless, of course _this_ is | |
211 | * the association the cause of the partial delivery. | |
212 | */ | |
213 | ||
b6e1331f | 214 | if (atomic_read(&sctp_sk(sk)->pd_mode) == 0) { |
1da177e4 | 215 | queue = &sk->sk_receive_queue; |
b6e1331f VY |
216 | } else { |
217 | if (ulpq->pd_mode) { | |
218 | /* If the association is in partial delivery, we | |
219 | * need to finish delivering the partially processed | |
220 | * packet before passing any other data. This is | |
221 | * because we don't truly support stream interleaving. | |
222 | */ | |
223 | if ((event->msg_flags & MSG_NOTIFICATION) || | |
224 | (SCTP_DATA_NOT_FRAG == | |
225 | (event->msg_flags & SCTP_DATA_FRAG_MASK))) | |
226 | queue = &sctp_sk(sk)->pd_lobby; | |
227 | else { | |
228 | clear_pd = event->msg_flags & MSG_EOR; | |
229 | queue = &sk->sk_receive_queue; | |
230 | } | |
231 | } else { | |
232 | /* | |
233 | * If fragment interleave is enabled, we | |
234 | * can queue this to the recieve queue instead | |
235 | * of the lobby. | |
236 | */ | |
237 | if (sctp_sk(sk)->frag_interleave) | |
238 | queue = &sk->sk_receive_queue; | |
239 | else | |
240 | queue = &sctp_sk(sk)->pd_lobby; | |
1da177e4 | 241 | } |
b6e1331f | 242 | } |
1da177e4 LT |
243 | |
244 | /* If we are harvesting multiple skbs they will be | |
245 | * collected on a list. | |
246 | */ | |
8728b834 DM |
247 | if (skb_list) |
248 | sctp_skb_list_tail(skb_list, queue); | |
1da177e4 | 249 | else |
8728b834 | 250 | __skb_queue_tail(queue, skb); |
1da177e4 LT |
251 | |
252 | /* Did we just complete partial delivery and need to get | |
253 | * rolling again? Move pending data to the receive | |
254 | * queue. | |
255 | */ | |
256 | if (clear_pd) | |
257 | sctp_ulpq_clear_pd(ulpq); | |
258 | ||
259 | if (queue == &sk->sk_receive_queue) | |
260 | sk->sk_data_ready(sk, 0); | |
261 | return 1; | |
262 | ||
263 | out_free: | |
8728b834 DM |
264 | if (skb_list) |
265 | sctp_queue_purge_ulpevents(skb_list); | |
1da177e4 LT |
266 | else |
267 | sctp_ulpevent_free(event); | |
8728b834 | 268 | |
1da177e4 LT |
269 | return 0; |
270 | } | |
271 | ||
272 | /* 2nd Level Abstractions */ | |
273 | ||
274 | /* Helper function to store chunks that need to be reassembled. */ | |
275 | static inline void sctp_ulpq_store_reasm(struct sctp_ulpq *ulpq, | |
276 | struct sctp_ulpevent *event) | |
277 | { | |
278 | struct sk_buff *pos; | |
279 | struct sctp_ulpevent *cevent; | |
280 | __u32 tsn, ctsn; | |
281 | ||
282 | tsn = event->tsn; | |
283 | ||
284 | /* See if it belongs at the end. */ | |
285 | pos = skb_peek_tail(&ulpq->reasm); | |
286 | if (!pos) { | |
287 | __skb_queue_tail(&ulpq->reasm, sctp_event2skb(event)); | |
288 | return; | |
289 | } | |
290 | ||
291 | /* Short circuit just dropping it at the end. */ | |
292 | cevent = sctp_skb2event(pos); | |
293 | ctsn = cevent->tsn; | |
294 | if (TSN_lt(ctsn, tsn)) { | |
295 | __skb_queue_tail(&ulpq->reasm, sctp_event2skb(event)); | |
296 | return; | |
297 | } | |
298 | ||
299 | /* Find the right place in this list. We store them by TSN. */ | |
300 | skb_queue_walk(&ulpq->reasm, pos) { | |
301 | cevent = sctp_skb2event(pos); | |
302 | ctsn = cevent->tsn; | |
303 | ||
304 | if (TSN_lt(tsn, ctsn)) | |
305 | break; | |
306 | } | |
307 | ||
308 | /* Insert before pos. */ | |
309 | __skb_insert(sctp_event2skb(event), pos->prev, pos, &ulpq->reasm); | |
310 | ||
311 | } | |
312 | ||
313 | /* Helper function to return an event corresponding to the reassembled | |
314 | * datagram. | |
315 | * This routine creates a re-assembled skb given the first and last skb's | |
316 | * as stored in the reassembly queue. The skb's may be non-linear if the sctp | |
317 | * payload was fragmented on the way and ip had to reassemble them. | |
318 | * We add the rest of skb's to the first skb's fraglist. | |
319 | */ | |
8728b834 | 320 | static struct sctp_ulpevent *sctp_make_reassembled_event(struct sk_buff_head *queue, struct sk_buff *f_frag, struct sk_buff *l_frag) |
1da177e4 LT |
321 | { |
322 | struct sk_buff *pos; | |
672e7cca | 323 | struct sk_buff *new = NULL; |
1da177e4 LT |
324 | struct sctp_ulpevent *event; |
325 | struct sk_buff *pnext, *last; | |
326 | struct sk_buff *list = skb_shinfo(f_frag)->frag_list; | |
327 | ||
328 | /* Store the pointer to the 2nd skb */ | |
329 | if (f_frag == l_frag) | |
330 | pos = NULL; | |
331 | else | |
332 | pos = f_frag->next; | |
333 | ||
334 | /* Get the last skb in the f_frag's frag_list if present. */ | |
335 | for (last = list; list; last = list, list = list->next); | |
336 | ||
337 | /* Add the list of remaining fragments to the first fragments | |
338 | * frag_list. | |
339 | */ | |
340 | if (last) | |
341 | last->next = pos; | |
d808ad9a YH |
342 | else { |
343 | if (skb_cloned(f_frag)) { | |
344 | /* This is a cloned skb, we can't just modify | |
345 | * the frag_list. We need a new skb to do that. | |
346 | * Instead of calling skb_unshare(), we'll do it | |
347 | * ourselves since we need to delay the free. | |
348 | */ | |
349 | new = skb_copy(f_frag, GFP_ATOMIC); | |
350 | if (!new) | |
351 | return NULL; /* try again later */ | |
352 | ||
353 | sctp_skb_set_owner_r(new, f_frag->sk); | |
354 | ||
355 | skb_shinfo(new)->frag_list = pos; | |
356 | } else | |
357 | skb_shinfo(f_frag)->frag_list = pos; | |
358 | } | |
1da177e4 LT |
359 | |
360 | /* Remove the first fragment from the reassembly queue. */ | |
8728b834 | 361 | __skb_unlink(f_frag, queue); |
672e7cca | 362 | |
d808ad9a YH |
363 | /* if we did unshare, then free the old skb and re-assign */ |
364 | if (new) { | |
365 | kfree_skb(f_frag); | |
366 | f_frag = new; | |
367 | } | |
672e7cca | 368 | |
1da177e4 LT |
369 | while (pos) { |
370 | ||
371 | pnext = pos->next; | |
372 | ||
373 | /* Update the len and data_len fields of the first fragment. */ | |
374 | f_frag->len += pos->len; | |
375 | f_frag->data_len += pos->len; | |
376 | ||
377 | /* Remove the fragment from the reassembly queue. */ | |
8728b834 | 378 | __skb_unlink(pos, queue); |
d808ad9a | 379 | |
1da177e4 LT |
380 | /* Break if we have reached the last fragment. */ |
381 | if (pos == l_frag) | |
382 | break; | |
383 | pos->next = pnext; | |
384 | pos = pnext; | |
385 | }; | |
386 | ||
387 | event = sctp_skb2event(f_frag); | |
388 | SCTP_INC_STATS(SCTP_MIB_REASMUSRMSGS); | |
389 | ||
390 | return event; | |
391 | } | |
392 | ||
393 | ||
394 | /* Helper function to check if an incoming chunk has filled up the last | |
395 | * missing fragment in a SCTP datagram and return the corresponding event. | |
396 | */ | |
397 | static inline struct sctp_ulpevent *sctp_ulpq_retrieve_reassembled(struct sctp_ulpq *ulpq) | |
398 | { | |
399 | struct sk_buff *pos; | |
400 | struct sctp_ulpevent *cevent; | |
401 | struct sk_buff *first_frag = NULL; | |
402 | __u32 ctsn, next_tsn; | |
403 | struct sctp_ulpevent *retval = NULL; | |
404 | ||
405 | /* Initialized to 0 just to avoid compiler warning message. Will | |
406 | * never be used with this value. It is referenced only after it | |
407 | * is set when we find the first fragment of a message. | |
408 | */ | |
409 | next_tsn = 0; | |
410 | ||
411 | /* The chunks are held in the reasm queue sorted by TSN. | |
412 | * Walk through the queue sequentially and look for a sequence of | |
413 | * fragmented chunks that complete a datagram. | |
414 | * 'first_frag' and next_tsn are reset when we find a chunk which | |
415 | * is the first fragment of a datagram. Once these 2 fields are set | |
416 | * we expect to find the remaining middle fragments and the last | |
417 | * fragment in order. If not, first_frag is reset to NULL and we | |
418 | * start the next pass when we find another first fragment. | |
419 | */ | |
420 | skb_queue_walk(&ulpq->reasm, pos) { | |
421 | cevent = sctp_skb2event(pos); | |
422 | ctsn = cevent->tsn; | |
423 | ||
424 | switch (cevent->msg_flags & SCTP_DATA_FRAG_MASK) { | |
425 | case SCTP_DATA_FIRST_FRAG: | |
426 | first_frag = pos; | |
427 | next_tsn = ctsn + 1; | |
428 | break; | |
429 | ||
430 | case SCTP_DATA_MIDDLE_FRAG: | |
431 | if ((first_frag) && (ctsn == next_tsn)) | |
432 | next_tsn++; | |
433 | else | |
434 | first_frag = NULL; | |
435 | break; | |
436 | ||
437 | case SCTP_DATA_LAST_FRAG: | |
438 | if (first_frag && (ctsn == next_tsn)) | |
439 | goto found; | |
440 | else | |
441 | first_frag = NULL; | |
442 | break; | |
443 | }; | |
444 | ||
445 | } | |
446 | done: | |
447 | return retval; | |
448 | found: | |
8728b834 | 449 | retval = sctp_make_reassembled_event(&ulpq->reasm, first_frag, pos); |
1da177e4 LT |
450 | if (retval) |
451 | retval->msg_flags |= MSG_EOR; | |
452 | goto done; | |
453 | } | |
454 | ||
455 | /* Retrieve the next set of fragments of a partial message. */ | |
456 | static inline struct sctp_ulpevent *sctp_ulpq_retrieve_partial(struct sctp_ulpq *ulpq) | |
457 | { | |
458 | struct sk_buff *pos, *last_frag, *first_frag; | |
459 | struct sctp_ulpevent *cevent; | |
460 | __u32 ctsn, next_tsn; | |
461 | int is_last; | |
462 | struct sctp_ulpevent *retval; | |
463 | ||
464 | /* The chunks are held in the reasm queue sorted by TSN. | |
465 | * Walk through the queue sequentially and look for the first | |
466 | * sequence of fragmented chunks. | |
467 | */ | |
468 | ||
469 | if (skb_queue_empty(&ulpq->reasm)) | |
470 | return NULL; | |
471 | ||
472 | last_frag = first_frag = NULL; | |
473 | retval = NULL; | |
474 | next_tsn = 0; | |
475 | is_last = 0; | |
476 | ||
477 | skb_queue_walk(&ulpq->reasm, pos) { | |
478 | cevent = sctp_skb2event(pos); | |
479 | ctsn = cevent->tsn; | |
480 | ||
481 | switch (cevent->msg_flags & SCTP_DATA_FRAG_MASK) { | |
482 | case SCTP_DATA_MIDDLE_FRAG: | |
483 | if (!first_frag) { | |
484 | first_frag = pos; | |
485 | next_tsn = ctsn + 1; | |
486 | last_frag = pos; | |
487 | } else if (next_tsn == ctsn) | |
488 | next_tsn++; | |
489 | else | |
490 | goto done; | |
491 | break; | |
492 | case SCTP_DATA_LAST_FRAG: | |
493 | if (!first_frag) | |
494 | first_frag = pos; | |
495 | else if (ctsn != next_tsn) | |
496 | goto done; | |
497 | last_frag = pos; | |
498 | is_last = 1; | |
499 | goto done; | |
500 | default: | |
501 | return NULL; | |
502 | }; | |
503 | } | |
504 | ||
505 | /* We have the reassembled event. There is no need to look | |
506 | * further. | |
507 | */ | |
508 | done: | |
8728b834 | 509 | retval = sctp_make_reassembled_event(&ulpq->reasm, first_frag, last_frag); |
1da177e4 LT |
510 | if (retval && is_last) |
511 | retval->msg_flags |= MSG_EOR; | |
512 | ||
513 | return retval; | |
514 | } | |
515 | ||
516 | ||
517 | /* Helper function to reassemble chunks. Hold chunks on the reasm queue that | |
518 | * need reassembling. | |
519 | */ | |
520 | static struct sctp_ulpevent *sctp_ulpq_reasm(struct sctp_ulpq *ulpq, | |
521 | struct sctp_ulpevent *event) | |
522 | { | |
523 | struct sctp_ulpevent *retval = NULL; | |
524 | ||
525 | /* Check if this is part of a fragmented message. */ | |
526 | if (SCTP_DATA_NOT_FRAG == (event->msg_flags & SCTP_DATA_FRAG_MASK)) { | |
527 | event->msg_flags |= MSG_EOR; | |
528 | return event; | |
529 | } | |
530 | ||
531 | sctp_ulpq_store_reasm(ulpq, event); | |
532 | if (!ulpq->pd_mode) | |
533 | retval = sctp_ulpq_retrieve_reassembled(ulpq); | |
534 | else { | |
535 | __u32 ctsn, ctsnap; | |
536 | ||
537 | /* Do not even bother unless this is the next tsn to | |
538 | * be delivered. | |
539 | */ | |
540 | ctsn = event->tsn; | |
541 | ctsnap = sctp_tsnmap_get_ctsn(&ulpq->asoc->peer.tsn_map); | |
542 | if (TSN_lte(ctsn, ctsnap)) | |
543 | retval = sctp_ulpq_retrieve_partial(ulpq); | |
544 | } | |
545 | ||
546 | return retval; | |
547 | } | |
548 | ||
549 | /* Retrieve the first part (sequential fragments) for partial delivery. */ | |
550 | static inline struct sctp_ulpevent *sctp_ulpq_retrieve_first(struct sctp_ulpq *ulpq) | |
551 | { | |
552 | struct sk_buff *pos, *last_frag, *first_frag; | |
553 | struct sctp_ulpevent *cevent; | |
554 | __u32 ctsn, next_tsn; | |
555 | struct sctp_ulpevent *retval; | |
556 | ||
557 | /* The chunks are held in the reasm queue sorted by TSN. | |
558 | * Walk through the queue sequentially and look for a sequence of | |
559 | * fragmented chunks that start a datagram. | |
560 | */ | |
561 | ||
562 | if (skb_queue_empty(&ulpq->reasm)) | |
563 | return NULL; | |
564 | ||
565 | last_frag = first_frag = NULL; | |
566 | retval = NULL; | |
567 | next_tsn = 0; | |
568 | ||
569 | skb_queue_walk(&ulpq->reasm, pos) { | |
570 | cevent = sctp_skb2event(pos); | |
571 | ctsn = cevent->tsn; | |
572 | ||
573 | switch (cevent->msg_flags & SCTP_DATA_FRAG_MASK) { | |
574 | case SCTP_DATA_FIRST_FRAG: | |
575 | if (!first_frag) { | |
576 | first_frag = pos; | |
577 | next_tsn = ctsn + 1; | |
578 | last_frag = pos; | |
579 | } else | |
580 | goto done; | |
581 | break; | |
582 | ||
583 | case SCTP_DATA_MIDDLE_FRAG: | |
584 | if (!first_frag) | |
585 | return NULL; | |
586 | if (ctsn == next_tsn) { | |
587 | next_tsn++; | |
588 | last_frag = pos; | |
589 | } else | |
590 | goto done; | |
591 | break; | |
592 | default: | |
593 | return NULL; | |
594 | }; | |
595 | } | |
596 | ||
597 | /* We have the reassembled event. There is no need to look | |
598 | * further. | |
599 | */ | |
600 | done: | |
8728b834 | 601 | retval = sctp_make_reassembled_event(&ulpq->reasm, first_frag, last_frag); |
1da177e4 LT |
602 | return retval; |
603 | } | |
604 | ||
605 | /* Helper function to gather skbs that have possibly become | |
606 | * ordered by an an incoming chunk. | |
607 | */ | |
608 | static inline void sctp_ulpq_retrieve_ordered(struct sctp_ulpq *ulpq, | |
609 | struct sctp_ulpevent *event) | |
610 | { | |
8728b834 | 611 | struct sk_buff_head *event_list; |
1da177e4 LT |
612 | struct sk_buff *pos, *tmp; |
613 | struct sctp_ulpevent *cevent; | |
614 | struct sctp_stream *in; | |
615 | __u16 sid, csid; | |
616 | __u16 ssn, cssn; | |
617 | ||
618 | sid = event->stream; | |
619 | ssn = event->ssn; | |
620 | in = &ulpq->asoc->ssnmap->in; | |
621 | ||
8728b834 DM |
622 | event_list = (struct sk_buff_head *) sctp_event2skb(event)->prev; |
623 | ||
1da177e4 LT |
624 | /* We are holding the chunks by stream, by SSN. */ |
625 | sctp_skb_for_each(pos, &ulpq->lobby, tmp) { | |
626 | cevent = (struct sctp_ulpevent *) pos->cb; | |
627 | csid = cevent->stream; | |
628 | cssn = cevent->ssn; | |
629 | ||
630 | /* Have we gone too far? */ | |
631 | if (csid > sid) | |
632 | break; | |
633 | ||
634 | /* Have we not gone far enough? */ | |
635 | if (csid < sid) | |
636 | continue; | |
637 | ||
638 | if (cssn != sctp_ssn_peek(in, sid)) | |
639 | break; | |
640 | ||
641 | /* Found it, so mark in the ssnmap. */ | |
642 | sctp_ssn_next(in, sid); | |
643 | ||
8728b834 | 644 | __skb_unlink(pos, &ulpq->lobby); |
1da177e4 LT |
645 | |
646 | /* Attach all gathered skbs to the event. */ | |
8728b834 | 647 | __skb_queue_tail(event_list, pos); |
1da177e4 LT |
648 | } |
649 | } | |
650 | ||
651 | /* Helper function to store chunks needing ordering. */ | |
652 | static inline void sctp_ulpq_store_ordered(struct sctp_ulpq *ulpq, | |
653 | struct sctp_ulpevent *event) | |
654 | { | |
655 | struct sk_buff *pos; | |
656 | struct sctp_ulpevent *cevent; | |
657 | __u16 sid, csid; | |
658 | __u16 ssn, cssn; | |
659 | ||
660 | pos = skb_peek_tail(&ulpq->lobby); | |
661 | if (!pos) { | |
662 | __skb_queue_tail(&ulpq->lobby, sctp_event2skb(event)); | |
663 | return; | |
664 | } | |
665 | ||
666 | sid = event->stream; | |
667 | ssn = event->ssn; | |
d808ad9a | 668 | |
1da177e4 LT |
669 | cevent = (struct sctp_ulpevent *) pos->cb; |
670 | csid = cevent->stream; | |
671 | cssn = cevent->ssn; | |
672 | if (sid > csid) { | |
673 | __skb_queue_tail(&ulpq->lobby, sctp_event2skb(event)); | |
674 | return; | |
675 | } | |
676 | ||
677 | if ((sid == csid) && SSN_lt(cssn, ssn)) { | |
678 | __skb_queue_tail(&ulpq->lobby, sctp_event2skb(event)); | |
679 | return; | |
680 | } | |
681 | ||
682 | /* Find the right place in this list. We store them by | |
683 | * stream ID and then by SSN. | |
684 | */ | |
685 | skb_queue_walk(&ulpq->lobby, pos) { | |
686 | cevent = (struct sctp_ulpevent *) pos->cb; | |
687 | csid = cevent->stream; | |
688 | cssn = cevent->ssn; | |
689 | ||
690 | if (csid > sid) | |
691 | break; | |
692 | if (csid == sid && SSN_lt(ssn, cssn)) | |
693 | break; | |
694 | } | |
695 | ||
696 | ||
697 | /* Insert before pos. */ | |
698 | __skb_insert(sctp_event2skb(event), pos->prev, pos, &ulpq->lobby); | |
699 | ||
700 | } | |
701 | ||
702 | static struct sctp_ulpevent *sctp_ulpq_order(struct sctp_ulpq *ulpq, | |
8728b834 | 703 | struct sctp_ulpevent *event) |
1da177e4 LT |
704 | { |
705 | __u16 sid, ssn; | |
706 | struct sctp_stream *in; | |
707 | ||
708 | /* Check if this message needs ordering. */ | |
709 | if (SCTP_DATA_UNORDERED & event->msg_flags) | |
710 | return event; | |
711 | ||
712 | /* Note: The stream ID must be verified before this routine. */ | |
713 | sid = event->stream; | |
714 | ssn = event->ssn; | |
715 | in = &ulpq->asoc->ssnmap->in; | |
716 | ||
717 | /* Is this the expected SSN for this stream ID? */ | |
718 | if (ssn != sctp_ssn_peek(in, sid)) { | |
719 | /* We've received something out of order, so find where it | |
720 | * needs to be placed. We order by stream and then by SSN. | |
721 | */ | |
722 | sctp_ulpq_store_ordered(ulpq, event); | |
723 | return NULL; | |
724 | } | |
725 | ||
726 | /* Mark that the next chunk has been found. */ | |
727 | sctp_ssn_next(in, sid); | |
728 | ||
729 | /* Go find any other chunks that were waiting for | |
730 | * ordering. | |
731 | */ | |
732 | sctp_ulpq_retrieve_ordered(ulpq, event); | |
733 | ||
734 | return event; | |
735 | } | |
736 | ||
737 | /* Helper function to gather skbs that have possibly become | |
738 | * ordered by forward tsn skipping their dependencies. | |
739 | */ | |
740 | static inline void sctp_ulpq_reap_ordered(struct sctp_ulpq *ulpq) | |
741 | { | |
742 | struct sk_buff *pos, *tmp; | |
743 | struct sctp_ulpevent *cevent; | |
8728b834 | 744 | struct sctp_ulpevent *event; |
1da177e4 LT |
745 | struct sctp_stream *in; |
746 | struct sk_buff_head temp; | |
747 | __u16 csid, cssn; | |
748 | ||
749 | in = &ulpq->asoc->ssnmap->in; | |
750 | ||
751 | /* We are holding the chunks by stream, by SSN. */ | |
8728b834 DM |
752 | skb_queue_head_init(&temp); |
753 | event = NULL; | |
1da177e4 LT |
754 | sctp_skb_for_each(pos, &ulpq->lobby, tmp) { |
755 | cevent = (struct sctp_ulpevent *) pos->cb; | |
756 | csid = cevent->stream; | |
757 | cssn = cevent->ssn; | |
758 | ||
759 | if (cssn != sctp_ssn_peek(in, csid)) | |
760 | break; | |
761 | ||
d808ad9a | 762 | /* Found it, so mark in the ssnmap. */ |
1da177e4 LT |
763 | sctp_ssn_next(in, csid); |
764 | ||
8728b834 | 765 | __skb_unlink(pos, &ulpq->lobby); |
d808ad9a | 766 | if (!event) { |
1da177e4 LT |
767 | /* Create a temporary list to collect chunks on. */ |
768 | event = sctp_skb2event(pos); | |
1da177e4 LT |
769 | __skb_queue_tail(&temp, sctp_event2skb(event)); |
770 | } else { | |
771 | /* Attach all gathered skbs to the event. */ | |
8728b834 | 772 | __skb_queue_tail(&temp, pos); |
1da177e4 LT |
773 | } |
774 | } | |
775 | ||
8728b834 DM |
776 | /* Send event to the ULP. 'event' is the sctp_ulpevent for |
777 | * very first SKB on the 'temp' list. | |
778 | */ | |
1da177e4 LT |
779 | if (event) |
780 | sctp_ulpq_tail_event(ulpq, event); | |
781 | } | |
782 | ||
783 | /* Skip over an SSN. */ | |
784 | void sctp_ulpq_skip(struct sctp_ulpq *ulpq, __u16 sid, __u16 ssn) | |
785 | { | |
786 | struct sctp_stream *in; | |
787 | ||
788 | /* Note: The stream ID must be verified before this routine. */ | |
789 | in = &ulpq->asoc->ssnmap->in; | |
790 | ||
791 | /* Is this an old SSN? If so ignore. */ | |
792 | if (SSN_lt(ssn, sctp_ssn_peek(in, sid))) | |
793 | return; | |
794 | ||
795 | /* Mark that we are no longer expecting this SSN or lower. */ | |
796 | sctp_ssn_skip(in, sid, ssn); | |
797 | ||
798 | /* Go find any other chunks that were waiting for | |
d808ad9a | 799 | * ordering and deliver them if needed. |
1da177e4 LT |
800 | */ |
801 | sctp_ulpq_reap_ordered(ulpq); | |
802 | return; | |
803 | } | |
804 | ||
805 | /* Renege 'needed' bytes from the ordering queue. */ | |
806 | static __u16 sctp_ulpq_renege_order(struct sctp_ulpq *ulpq, __u16 needed) | |
807 | { | |
808 | __u16 freed = 0; | |
809 | __u32 tsn; | |
810 | struct sk_buff *skb; | |
811 | struct sctp_ulpevent *event; | |
812 | struct sctp_tsnmap *tsnmap; | |
813 | ||
814 | tsnmap = &ulpq->asoc->peer.tsn_map; | |
815 | ||
816 | while ((skb = __skb_dequeue_tail(&ulpq->lobby)) != NULL) { | |
817 | freed += skb_headlen(skb); | |
818 | event = sctp_skb2event(skb); | |
819 | tsn = event->tsn; | |
820 | ||
821 | sctp_ulpevent_free(event); | |
822 | sctp_tsnmap_renege(tsnmap, tsn); | |
823 | if (freed >= needed) | |
824 | return freed; | |
825 | } | |
826 | ||
827 | return freed; | |
828 | } | |
829 | ||
830 | /* Renege 'needed' bytes from the reassembly queue. */ | |
831 | static __u16 sctp_ulpq_renege_frags(struct sctp_ulpq *ulpq, __u16 needed) | |
832 | { | |
833 | __u16 freed = 0; | |
834 | __u32 tsn; | |
835 | struct sk_buff *skb; | |
836 | struct sctp_ulpevent *event; | |
837 | struct sctp_tsnmap *tsnmap; | |
838 | ||
839 | tsnmap = &ulpq->asoc->peer.tsn_map; | |
840 | ||
841 | /* Walk backwards through the list, reneges the newest tsns. */ | |
842 | while ((skb = __skb_dequeue_tail(&ulpq->reasm)) != NULL) { | |
843 | freed += skb_headlen(skb); | |
844 | event = sctp_skb2event(skb); | |
845 | tsn = event->tsn; | |
846 | ||
847 | sctp_ulpevent_free(event); | |
848 | sctp_tsnmap_renege(tsnmap, tsn); | |
849 | if (freed >= needed) | |
850 | return freed; | |
851 | } | |
852 | ||
853 | return freed; | |
854 | } | |
855 | ||
856 | /* Partial deliver the first message as there is pressure on rwnd. */ | |
857 | void sctp_ulpq_partial_delivery(struct sctp_ulpq *ulpq, | |
3182cd84 | 858 | struct sctp_chunk *chunk, |
dd0fc66f | 859 | gfp_t gfp) |
1da177e4 LT |
860 | { |
861 | struct sctp_ulpevent *event; | |
862 | struct sctp_association *asoc; | |
b6e1331f | 863 | struct sctp_sock *sp; |
1da177e4 LT |
864 | |
865 | asoc = ulpq->asoc; | |
b6e1331f | 866 | sp = sctp_sk(asoc->base.sk); |
1da177e4 | 867 | |
b6e1331f VY |
868 | /* If the association is already in Partial Delivery mode |
869 | * we have noting to do. | |
870 | */ | |
871 | if (ulpq->pd_mode) | |
872 | return; | |
1da177e4 | 873 | |
b6e1331f VY |
874 | /* If the user enabled fragment interleave socket option, |
875 | * multiple associations can enter partial delivery. | |
876 | * Otherwise, we can only enter partial delivery if the | |
877 | * socket is not in partial deliver mode. | |
878 | */ | |
879 | if (sp->frag_interleave || atomic_read(&sp->pd_mode) == 0) { | |
1da177e4 LT |
880 | /* Is partial delivery possible? */ |
881 | event = sctp_ulpq_retrieve_first(ulpq); | |
882 | /* Send event to the ULP. */ | |
883 | if (event) { | |
884 | sctp_ulpq_tail_event(ulpq, event); | |
b6e1331f | 885 | atomic_inc(&sp->pd_mode); |
1da177e4 LT |
886 | ulpq->pd_mode = 1; |
887 | return; | |
888 | } | |
889 | } | |
890 | } | |
891 | ||
892 | /* Renege some packets to make room for an incoming chunk. */ | |
893 | void sctp_ulpq_renege(struct sctp_ulpq *ulpq, struct sctp_chunk *chunk, | |
dd0fc66f | 894 | gfp_t gfp) |
1da177e4 LT |
895 | { |
896 | struct sctp_association *asoc; | |
897 | __u16 needed, freed; | |
898 | ||
899 | asoc = ulpq->asoc; | |
900 | ||
901 | if (chunk) { | |
902 | needed = ntohs(chunk->chunk_hdr->length); | |
903 | needed -= sizeof(sctp_data_chunk_t); | |
d808ad9a | 904 | } else |
1da177e4 LT |
905 | needed = SCTP_DEFAULT_MAXWINDOW; |
906 | ||
907 | freed = 0; | |
908 | ||
909 | if (skb_queue_empty(&asoc->base.sk->sk_receive_queue)) { | |
910 | freed = sctp_ulpq_renege_order(ulpq, needed); | |
911 | if (freed < needed) { | |
912 | freed += sctp_ulpq_renege_frags(ulpq, needed - freed); | |
913 | } | |
914 | } | |
915 | /* If able to free enough room, accept this chunk. */ | |
916 | if (chunk && (freed >= needed)) { | |
917 | __u32 tsn; | |
918 | tsn = ntohl(chunk->subh.data_hdr->tsn); | |
919 | sctp_tsnmap_mark(&asoc->peer.tsn_map, tsn); | |
920 | sctp_ulpq_tail_data(ulpq, chunk, gfp); | |
d808ad9a | 921 | |
1da177e4 LT |
922 | sctp_ulpq_partial_delivery(ulpq, chunk, gfp); |
923 | } | |
924 | ||
925 | return; | |
926 | } | |
927 | ||
928 | ||
929 | ||
930 | /* Notify the application if an association is aborted and in | |
931 | * partial delivery mode. Send up any pending received messages. | |
932 | */ | |
dd0fc66f | 933 | void sctp_ulpq_abort_pd(struct sctp_ulpq *ulpq, gfp_t gfp) |
1da177e4 LT |
934 | { |
935 | struct sctp_ulpevent *ev = NULL; | |
936 | struct sock *sk; | |
937 | ||
938 | if (!ulpq->pd_mode) | |
939 | return; | |
940 | ||
941 | sk = ulpq->asoc->base.sk; | |
942 | if (sctp_ulpevent_type_enabled(SCTP_PARTIAL_DELIVERY_EVENT, | |
943 | &sctp_sk(sk)->subscribe)) | |
944 | ev = sctp_ulpevent_make_pdapi(ulpq->asoc, | |
945 | SCTP_PARTIAL_DELIVERY_ABORTED, | |
946 | gfp); | |
947 | if (ev) | |
948 | __skb_queue_tail(&sk->sk_receive_queue, sctp_event2skb(ev)); | |
949 | ||
950 | /* If there is data waiting, send it up the socket now. */ | |
951 | if (sctp_ulpq_clear_pd(ulpq) || ev) | |
952 | sk->sk_data_ready(sk, 0); | |
953 | } |