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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) 2001-2003 Intel Corp. |
6 | * |
7 | * This file is part of the SCTP kernel implementation |
8 | * |
9 | * These functions implement the sctp_outq class. The outqueue handles |
10 | * bundling and queueing of outgoing SCTP chunks. |
11 | * |
12 | * This SCTP implementation is free software; |
13 | * you can redistribute it and/or modify it under the terms of |
14 | * the GNU General Public License as published by |
15 | * the Free Software Foundation; either version 2, or (at your option) |
16 | * any later version. |
17 | * |
18 | * This SCTP implementation is distributed in the hope that it |
19 | * will be useful, but WITHOUT ANY WARRANTY; without even the implied |
20 | * ************************ |
21 | * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. |
22 | * See the GNU General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU General Public License |
25 | * along with GNU CC; see the file COPYING. If not, write to |
26 | * the Free Software Foundation, 59 Temple Place - Suite 330, |
27 | * Boston, MA 02111-1307, USA. |
28 | * |
29 | * Please send any bug reports or fixes you make to the |
30 | * email address(es): |
31 | * lksctp developers <lksctp-developers@lists.sourceforge.net> |
32 | * |
33 | * Or submit a bug report through the following website: |
34 | * http://www.sf.net/projects/lksctp |
35 | * |
36 | * Written or modified by: |
37 | * La Monte H.P. Yarroll <piggy@acm.org> |
38 | * Karl Knutson <karl@athena.chicago.il.us> |
39 | * Perry Melange <pmelange@null.cc.uic.edu> |
40 | * Xingang Guo <xingang.guo@intel.com> |
41 | * Hui Huang <hui.huang@nokia.com> |
42 | * Sridhar Samudrala <sri@us.ibm.com> |
43 | * Jon Grimm <jgrimm@us.ibm.com> |
44 | * |
45 | * Any bugs reported given to us we will try to fix... any fixes shared will |
46 | * be incorporated into the next SCTP release. |
47 | */ |
48 | |
49 | #include <linux/types.h> |
50 | #include <linux/list.h> /* For struct list_head */ |
51 | #include <linux/socket.h> |
52 | #include <linux/ip.h> |
53 | #include <linux/slab.h> |
54 | #include <net/sock.h> /* For skb_set_owner_w */ |
55 | |
56 | #include <net/sctp/sctp.h> |
57 | #include <net/sctp/sm.h> |
58 | |
59 | /* Declare internal functions here. */ |
60 | static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn); |
61 | static void sctp_check_transmitted(struct sctp_outq *q, |
62 | struct list_head *transmitted_queue, |
63 | struct sctp_transport *transport, |
64 | struct sctp_sackhdr *sack, |
65 | __u32 *highest_new_tsn); |
66 | |
67 | static void sctp_mark_missing(struct sctp_outq *q, |
68 | struct list_head *transmitted_queue, |
69 | struct sctp_transport *transport, |
70 | __u32 highest_new_tsn, |
71 | int count_of_newacks); |
72 | |
73 | static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 sack_ctsn); |
74 | |
75 | static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout); |
76 | |
77 | /* Add data to the front of the queue. */ |
78 | static inline void sctp_outq_head_data(struct sctp_outq *q, |
79 | struct sctp_chunk *ch) |
80 | { |
81 | list_add(&ch->list, &q->out_chunk_list); |
82 | q->out_qlen += ch->skb->len; |
83 | } |
84 | |
85 | /* Take data from the front of the queue. */ |
86 | static inline struct sctp_chunk *sctp_outq_dequeue_data(struct sctp_outq *q) |
87 | { |
88 | struct sctp_chunk *ch = NULL; |
89 | |
90 | if (!list_empty(&q->out_chunk_list)) { |
91 | struct list_head *entry = q->out_chunk_list.next; |
92 | |
93 | ch = list_entry(entry, struct sctp_chunk, list); |
94 | list_del_init(entry); |
95 | q->out_qlen -= ch->skb->len; |
96 | } |
97 | return ch; |
98 | } |
99 | /* Add data chunk to the end of the queue. */ |
100 | static inline void sctp_outq_tail_data(struct sctp_outq *q, |
101 | struct sctp_chunk *ch) |
102 | { |
103 | list_add_tail(&ch->list, &q->out_chunk_list); |
104 | q->out_qlen += ch->skb->len; |
105 | } |
106 | |
107 | /* |
108 | * SFR-CACC algorithm: |
109 | * D) If count_of_newacks is greater than or equal to 2 |
110 | * and t was not sent to the current primary then the |
111 | * sender MUST NOT increment missing report count for t. |
112 | */ |
113 | static inline int sctp_cacc_skip_3_1_d(struct sctp_transport *primary, |
114 | struct sctp_transport *transport, |
115 | int count_of_newacks) |
116 | { |
117 | if (count_of_newacks >=2 && transport != primary) |
118 | return 1; |
119 | return 0; |
120 | } |
121 | |
122 | /* |
123 | * SFR-CACC algorithm: |
124 | * F) If count_of_newacks is less than 2, let d be the |
125 | * destination to which t was sent. If cacc_saw_newack |
126 | * is 0 for destination d, then the sender MUST NOT |
127 | * increment missing report count for t. |
128 | */ |
129 | static inline int sctp_cacc_skip_3_1_f(struct sctp_transport *transport, |
130 | int count_of_newacks) |
131 | { |
132 | if (count_of_newacks < 2 && !transport->cacc.cacc_saw_newack) |
133 | return 1; |
134 | return 0; |
135 | } |
136 | |
137 | /* |
138 | * SFR-CACC algorithm: |
139 | * 3.1) If CYCLING_CHANGEOVER is 0, the sender SHOULD |
140 | * execute steps C, D, F. |
141 | * |
142 | * C has been implemented in sctp_outq_sack |
143 | */ |
144 | static inline int sctp_cacc_skip_3_1(struct sctp_transport *primary, |
145 | struct sctp_transport *transport, |
146 | int count_of_newacks) |
147 | { |
148 | if (!primary->cacc.cycling_changeover) { |
149 | if (sctp_cacc_skip_3_1_d(primary, transport, count_of_newacks)) |
150 | return 1; |
151 | if (sctp_cacc_skip_3_1_f(transport, count_of_newacks)) |
152 | return 1; |
153 | return 0; |
154 | } |
155 | return 0; |
156 | } |
157 | |
158 | /* |
159 | * SFR-CACC algorithm: |
160 | * 3.2) Else if CYCLING_CHANGEOVER is 1, and t is less |
161 | * than next_tsn_at_change of the current primary, then |
162 | * the sender MUST NOT increment missing report count |
163 | * for t. |
164 | */ |
165 | static inline int sctp_cacc_skip_3_2(struct sctp_transport *primary, __u32 tsn) |
166 | { |
167 | if (primary->cacc.cycling_changeover && |
168 | TSN_lt(tsn, primary->cacc.next_tsn_at_change)) |
169 | return 1; |
170 | return 0; |
171 | } |
172 | |
173 | /* |
174 | * SFR-CACC algorithm: |
175 | * 3) If the missing report count for TSN t is to be |
176 | * incremented according to [RFC2960] and |
177 | * [SCTP_STEWART-2002], and CHANGEOVER_ACTIVE is set, |
178 | * then the sender MUST futher execute steps 3.1 and |
179 | * 3.2 to determine if the missing report count for |
180 | * TSN t SHOULD NOT be incremented. |
181 | * |
182 | * 3.3) If 3.1 and 3.2 do not dictate that the missing |
183 | * report count for t should not be incremented, then |
184 | * the sender SOULD increment missing report count for |
185 | * t (according to [RFC2960] and [SCTP_STEWART_2002]). |
186 | */ |
187 | static inline int sctp_cacc_skip(struct sctp_transport *primary, |
188 | struct sctp_transport *transport, |
189 | int count_of_newacks, |
190 | __u32 tsn) |
191 | { |
192 | if (primary->cacc.changeover_active && |
193 | (sctp_cacc_skip_3_1(primary, transport, count_of_newacks) || |
194 | sctp_cacc_skip_3_2(primary, tsn))) |
195 | return 1; |
196 | return 0; |
197 | } |
198 | |
199 | /* Initialize an existing sctp_outq. This does the boring stuff. |
200 | * You still need to define handlers if you really want to DO |
201 | * something with this structure... |
202 | */ |
203 | void sctp_outq_init(struct sctp_association *asoc, struct sctp_outq *q) |
204 | { |
205 | q->asoc = asoc; |
206 | INIT_LIST_HEAD(&q->out_chunk_list); |
207 | INIT_LIST_HEAD(&q->control_chunk_list); |
208 | INIT_LIST_HEAD(&q->retransmit); |
209 | INIT_LIST_HEAD(&q->sacked); |
210 | INIT_LIST_HEAD(&q->abandoned); |
211 | |
212 | q->fast_rtx = 0; |
213 | q->outstanding_bytes = 0; |
214 | q->empty = 1; |
215 | q->cork = 0; |
216 | |
217 | q->malloced = 0; |
218 | q->out_qlen = 0; |
219 | } |
220 | |
221 | /* Free the outqueue structure and any related pending chunks. |
222 | */ |
223 | void sctp_outq_teardown(struct sctp_outq *q) |
224 | { |
225 | struct sctp_transport *transport; |
226 | struct list_head *lchunk, *temp; |
227 | struct sctp_chunk *chunk, *tmp; |
228 | |
229 | /* Throw away unacknowledged chunks. */ |
230 | list_for_each_entry(transport, &q->asoc->peer.transport_addr_list, |
231 | transports) { |
232 | while ((lchunk = sctp_list_dequeue(&transport->transmitted)) != NULL) { |
233 | chunk = list_entry(lchunk, struct sctp_chunk, |
234 | transmitted_list); |
235 | /* Mark as part of a failed message. */ |
236 | sctp_chunk_fail(chunk, q->error); |
237 | sctp_chunk_free(chunk); |
238 | } |
239 | } |
240 | |
241 | /* Throw away chunks that have been gap ACKed. */ |
242 | list_for_each_safe(lchunk, temp, &q->sacked) { |
243 | list_del_init(lchunk); |
244 | chunk = list_entry(lchunk, struct sctp_chunk, |
245 | transmitted_list); |
246 | sctp_chunk_fail(chunk, q->error); |
247 | sctp_chunk_free(chunk); |
248 | } |
249 | |
250 | /* Throw away any chunks in the retransmit queue. */ |
251 | list_for_each_safe(lchunk, temp, &q->retransmit) { |
252 | list_del_init(lchunk); |
253 | chunk = list_entry(lchunk, struct sctp_chunk, |
254 | transmitted_list); |
255 | sctp_chunk_fail(chunk, q->error); |
256 | sctp_chunk_free(chunk); |
257 | } |
258 | |
259 | /* Throw away any chunks that are in the abandoned queue. */ |
260 | list_for_each_safe(lchunk, temp, &q->abandoned) { |
261 | list_del_init(lchunk); |
262 | chunk = list_entry(lchunk, struct sctp_chunk, |
263 | transmitted_list); |
264 | sctp_chunk_fail(chunk, q->error); |
265 | sctp_chunk_free(chunk); |
266 | } |
267 | |
268 | /* Throw away any leftover data chunks. */ |
269 | while ((chunk = sctp_outq_dequeue_data(q)) != NULL) { |
270 | |
271 | /* Mark as send failure. */ |
272 | sctp_chunk_fail(chunk, q->error); |
273 | sctp_chunk_free(chunk); |
274 | } |
275 | |
276 | q->error = 0; |
277 | |
278 | /* Throw away any leftover control chunks. */ |
279 | list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) { |
280 | list_del_init(&chunk->list); |
281 | sctp_chunk_free(chunk); |
282 | } |
283 | } |
284 | |
285 | /* Free the outqueue structure and any related pending chunks. */ |
286 | void sctp_outq_free(struct sctp_outq *q) |
287 | { |
288 | /* Throw away leftover chunks. */ |
289 | sctp_outq_teardown(q); |
290 | |
291 | /* If we were kmalloc()'d, free the memory. */ |
292 | if (q->malloced) |
293 | kfree(q); |
294 | } |
295 | |
296 | /* Put a new chunk in an sctp_outq. */ |
297 | int sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk) |
298 | { |
299 | int error = 0; |
300 | |
301 | SCTP_DEBUG_PRINTK("sctp_outq_tail(%p, %p[%s])\n", |
302 | q, chunk, chunk && chunk->chunk_hdr ? |
303 | sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) |
304 | : "Illegal Chunk"); |
305 | |
306 | /* If it is data, queue it up, otherwise, send it |
307 | * immediately. |
308 | */ |
309 | if (sctp_chunk_is_data(chunk)) { |
310 | /* Is it OK to queue data chunks? */ |
311 | /* From 9. Termination of Association |
312 | * |
313 | * When either endpoint performs a shutdown, the |
314 | * association on each peer will stop accepting new |
315 | * data from its user and only deliver data in queue |
316 | * at the time of sending or receiving the SHUTDOWN |
317 | * chunk. |
318 | */ |
319 | switch (q->asoc->state) { |
320 | case SCTP_STATE_EMPTY: |
321 | case SCTP_STATE_CLOSED: |
322 | case SCTP_STATE_SHUTDOWN_PENDING: |
323 | case SCTP_STATE_SHUTDOWN_SENT: |
324 | case SCTP_STATE_SHUTDOWN_RECEIVED: |
325 | case SCTP_STATE_SHUTDOWN_ACK_SENT: |
326 | /* Cannot send after transport endpoint shutdown */ |
327 | error = -ESHUTDOWN; |
328 | break; |
329 | |
330 | default: |
331 | SCTP_DEBUG_PRINTK("outqueueing (%p, %p[%s])\n", |
332 | q, chunk, chunk && chunk->chunk_hdr ? |
333 | sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) |
334 | : "Illegal Chunk"); |
335 | |
336 | sctp_outq_tail_data(q, chunk); |
337 | if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) |
338 | SCTP_INC_STATS(SCTP_MIB_OUTUNORDERCHUNKS); |
339 | else |
340 | SCTP_INC_STATS(SCTP_MIB_OUTORDERCHUNKS); |
341 | q->empty = 0; |
342 | break; |
343 | } |
344 | } else { |
345 | list_add_tail(&chunk->list, &q->control_chunk_list); |
346 | SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); |
347 | } |
348 | |
349 | if (error < 0) |
350 | return error; |
351 | |
352 | if (!q->cork) |
353 | error = sctp_outq_flush(q, 0); |
354 | |
355 | return error; |
356 | } |
357 | |
358 | /* Insert a chunk into the sorted list based on the TSNs. The retransmit list |
359 | * and the abandoned list are in ascending order. |
360 | */ |
361 | static void sctp_insert_list(struct list_head *head, struct list_head *new) |
362 | { |
363 | struct list_head *pos; |
364 | struct sctp_chunk *nchunk, *lchunk; |
365 | __u32 ntsn, ltsn; |
366 | int done = 0; |
367 | |
368 | nchunk = list_entry(new, struct sctp_chunk, transmitted_list); |
369 | ntsn = ntohl(nchunk->subh.data_hdr->tsn); |
370 | |
371 | list_for_each(pos, head) { |
372 | lchunk = list_entry(pos, struct sctp_chunk, transmitted_list); |
373 | ltsn = ntohl(lchunk->subh.data_hdr->tsn); |
374 | if (TSN_lt(ntsn, ltsn)) { |
375 | list_add(new, pos->prev); |
376 | done = 1; |
377 | break; |
378 | } |
379 | } |
380 | if (!done) |
381 | list_add_tail(new, head); |
382 | } |
383 | |
384 | /* Mark all the eligible packets on a transport for retransmission. */ |
385 | void sctp_retransmit_mark(struct sctp_outq *q, |
386 | struct sctp_transport *transport, |
387 | __u8 reason) |
388 | { |
389 | struct list_head *lchunk, *ltemp; |
390 | struct sctp_chunk *chunk; |
391 | |
392 | /* Walk through the specified transmitted queue. */ |
393 | list_for_each_safe(lchunk, ltemp, &transport->transmitted) { |
394 | chunk = list_entry(lchunk, struct sctp_chunk, |
395 | transmitted_list); |
396 | |
397 | /* If the chunk is abandoned, move it to abandoned list. */ |
398 | if (sctp_chunk_abandoned(chunk)) { |
399 | list_del_init(lchunk); |
400 | sctp_insert_list(&q->abandoned, lchunk); |
401 | |
402 | /* If this chunk has not been previousely acked, |
403 | * stop considering it 'outstanding'. Our peer |
404 | * will most likely never see it since it will |
405 | * not be retransmitted |
406 | */ |
407 | if (!chunk->tsn_gap_acked) { |
408 | if (chunk->transport) |
409 | chunk->transport->flight_size -= |
410 | sctp_data_size(chunk); |
411 | q->outstanding_bytes -= sctp_data_size(chunk); |
412 | q->asoc->peer.rwnd += (sctp_data_size(chunk) + |
413 | sizeof(struct sk_buff)); |
414 | } |
415 | continue; |
416 | } |
417 | |
418 | /* If we are doing retransmission due to a timeout or pmtu |
419 | * discovery, only the chunks that are not yet acked should |
420 | * be added to the retransmit queue. |
421 | */ |
422 | if ((reason == SCTP_RTXR_FAST_RTX && |
423 | (chunk->fast_retransmit == SCTP_NEED_FRTX)) || |
424 | (reason != SCTP_RTXR_FAST_RTX && !chunk->tsn_gap_acked)) { |
425 | /* RFC 2960 6.2.1 Processing a Received SACK |
426 | * |
427 | * C) Any time a DATA chunk is marked for |
428 | * retransmission (via either T3-rtx timer expiration |
429 | * (Section 6.3.3) or via fast retransmit |
430 | * (Section 7.2.4)), add the data size of those |
431 | * chunks to the rwnd. |
432 | */ |
433 | q->asoc->peer.rwnd += (sctp_data_size(chunk) + |
434 | sizeof(struct sk_buff)); |
435 | q->outstanding_bytes -= sctp_data_size(chunk); |
436 | if (chunk->transport) |
437 | transport->flight_size -= sctp_data_size(chunk); |
438 | |
439 | /* sctpimpguide-05 Section 2.8.2 |
440 | * M5) If a T3-rtx timer expires, the |
441 | * 'TSN.Missing.Report' of all affected TSNs is set |
442 | * to 0. |
443 | */ |
444 | chunk->tsn_missing_report = 0; |
445 | |
446 | /* If a chunk that is being used for RTT measurement |
447 | * has to be retransmitted, we cannot use this chunk |
448 | * anymore for RTT measurements. Reset rto_pending so |
449 | * that a new RTT measurement is started when a new |
450 | * data chunk is sent. |
451 | */ |
452 | if (chunk->rtt_in_progress) { |
453 | chunk->rtt_in_progress = 0; |
454 | transport->rto_pending = 0; |
455 | } |
456 | |
457 | /* Move the chunk to the retransmit queue. The chunks |
458 | * on the retransmit queue are always kept in order. |
459 | */ |
460 | list_del_init(lchunk); |
461 | sctp_insert_list(&q->retransmit, lchunk); |
462 | } |
463 | } |
464 | |
465 | SCTP_DEBUG_PRINTK("%s: transport: %p, reason: %d, " |
466 | "cwnd: %d, ssthresh: %d, flight_size: %d, " |
467 | "pba: %d\n", __func__, |
468 | transport, reason, |
469 | transport->cwnd, transport->ssthresh, |
470 | transport->flight_size, |
471 | transport->partial_bytes_acked); |
472 | |
473 | } |
474 | |
475 | /* Mark all the eligible packets on a transport for retransmission and force |
476 | * one packet out. |
477 | */ |
478 | void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport, |
479 | sctp_retransmit_reason_t reason) |
480 | { |
481 | int error = 0; |
482 | |
483 | switch(reason) { |
484 | case SCTP_RTXR_T3_RTX: |
485 | SCTP_INC_STATS(SCTP_MIB_T3_RETRANSMITS); |
486 | sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_T3_RTX); |
487 | /* Update the retran path if the T3-rtx timer has expired for |
488 | * the current retran path. |
489 | */ |
490 | if (transport == transport->asoc->peer.retran_path) |
491 | sctp_assoc_update_retran_path(transport->asoc); |
492 | transport->asoc->rtx_data_chunks += |
493 | transport->asoc->unack_data; |
494 | break; |
495 | case SCTP_RTXR_FAST_RTX: |
496 | SCTP_INC_STATS(SCTP_MIB_FAST_RETRANSMITS); |
497 | sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_FAST_RTX); |
498 | q->fast_rtx = 1; |
499 | break; |
500 | case SCTP_RTXR_PMTUD: |
501 | SCTP_INC_STATS(SCTP_MIB_PMTUD_RETRANSMITS); |
502 | break; |
503 | case SCTP_RTXR_T1_RTX: |
504 | SCTP_INC_STATS(SCTP_MIB_T1_RETRANSMITS); |
505 | transport->asoc->init_retries++; |
506 | break; |
507 | default: |
508 | BUG(); |
509 | } |
510 | |
511 | sctp_retransmit_mark(q, transport, reason); |
512 | |
513 | /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination, |
514 | * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by |
515 | * following the procedures outlined in C1 - C5. |
516 | */ |
517 | if (reason == SCTP_RTXR_T3_RTX) |
518 | sctp_generate_fwdtsn(q, q->asoc->ctsn_ack_point); |
519 | |
520 | /* Flush the queues only on timeout, since fast_rtx is only |
521 | * triggered during sack processing and the queue |
522 | * will be flushed at the end. |
523 | */ |
524 | if (reason != SCTP_RTXR_FAST_RTX) |
525 | error = sctp_outq_flush(q, /* rtx_timeout */ 1); |
526 | |
527 | if (error) |
528 | q->asoc->base.sk->sk_err = -error; |
529 | } |
530 | |
531 | /* |
532 | * Transmit DATA chunks on the retransmit queue. Upon return from |
533 | * sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which |
534 | * need to be transmitted by the caller. |
535 | * We assume that pkt->transport has already been set. |
536 | * |
537 | * The return value is a normal kernel error return value. |
538 | */ |
539 | static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt, |
540 | int rtx_timeout, int *start_timer) |
541 | { |
542 | struct list_head *lqueue; |
543 | struct sctp_transport *transport = pkt->transport; |
544 | sctp_xmit_t status; |
545 | struct sctp_chunk *chunk, *chunk1; |
546 | struct sctp_association *asoc; |
547 | int fast_rtx; |
548 | int error = 0; |
549 | int timer = 0; |
550 | int done = 0; |
551 | |
552 | asoc = q->asoc; |
553 | lqueue = &q->retransmit; |
554 | fast_rtx = q->fast_rtx; |
555 | |
556 | /* This loop handles time-out retransmissions, fast retransmissions, |
557 | * and retransmissions due to opening of whindow. |
558 | * |
559 | * RFC 2960 6.3.3 Handle T3-rtx Expiration |
560 | * |
561 | * E3) Determine how many of the earliest (i.e., lowest TSN) |
562 | * outstanding DATA chunks for the address for which the |
563 | * T3-rtx has expired will fit into a single packet, subject |
564 | * to the MTU constraint for the path corresponding to the |
565 | * destination transport address to which the retransmission |
566 | * is being sent (this may be different from the address for |
567 | * which the timer expires [see Section 6.4]). Call this value |
568 | * K. Bundle and retransmit those K DATA chunks in a single |
569 | * packet to the destination endpoint. |
570 | * |
571 | * [Just to be painfully clear, if we are retransmitting |
572 | * because a timeout just happened, we should send only ONE |
573 | * packet of retransmitted data.] |
574 | * |
575 | * For fast retransmissions we also send only ONE packet. However, |
576 | * if we are just flushing the queue due to open window, we'll |
577 | * try to send as much as possible. |
578 | */ |
579 | list_for_each_entry_safe(chunk, chunk1, lqueue, transmitted_list) { |
580 | |
581 | /* Make sure that Gap Acked TSNs are not retransmitted. A |
582 | * simple approach is just to move such TSNs out of the |
583 | * way and into a 'transmitted' queue and skip to the |
584 | * next chunk. |
585 | */ |
586 | if (chunk->tsn_gap_acked) { |
587 | list_del(&chunk->transmitted_list); |
588 | list_add_tail(&chunk->transmitted_list, |
589 | &transport->transmitted); |
590 | continue; |
591 | } |
592 | |
593 | /* If we are doing fast retransmit, ignore non-fast_rtransmit |
594 | * chunks |
595 | */ |
596 | if (fast_rtx && !chunk->fast_retransmit) |
597 | continue; |
598 | |
599 | redo: |
600 | /* Attempt to append this chunk to the packet. */ |
601 | status = sctp_packet_append_chunk(pkt, chunk); |
602 | |
603 | switch (status) { |
604 | case SCTP_XMIT_PMTU_FULL: |
605 | if (!pkt->has_data && !pkt->has_cookie_echo) { |
606 | /* If this packet did not contain DATA then |
607 | * retransmission did not happen, so do it |
608 | * again. We'll ignore the error here since |
609 | * control chunks are already freed so there |
610 | * is nothing we can do. |
611 | */ |
612 | sctp_packet_transmit(pkt); |
613 | goto redo; |
614 | } |
615 | |
616 | /* Send this packet. */ |
617 | error = sctp_packet_transmit(pkt); |
618 | |
619 | /* If we are retransmitting, we should only |
620 | * send a single packet. |
621 | */ |
622 | if (rtx_timeout || fast_rtx) |
623 | done = 1; |
624 | |
625 | /* Bundle next chunk in the next round. */ |
626 | break; |
627 | |
628 | case SCTP_XMIT_RWND_FULL: |
629 | /* Send this packet. */ |
630 | error = sctp_packet_transmit(pkt); |
631 | |
632 | /* Stop sending DATA as there is no more room |
633 | * at the receiver. |
634 | */ |
635 | done = 1; |
636 | break; |
637 | |
638 | case SCTP_XMIT_NAGLE_DELAY: |
639 | /* Send this packet. */ |
640 | error = sctp_packet_transmit(pkt); |
641 | |
642 | /* Stop sending DATA because of nagle delay. */ |
643 | done = 1; |
644 | break; |
645 | |
646 | default: |
647 | /* The append was successful, so add this chunk to |
648 | * the transmitted list. |
649 | */ |
650 | list_del(&chunk->transmitted_list); |
651 | list_add_tail(&chunk->transmitted_list, |
652 | &transport->transmitted); |
653 | |
654 | /* Mark the chunk as ineligible for fast retransmit |
655 | * after it is retransmitted. |
656 | */ |
657 | if (chunk->fast_retransmit == SCTP_NEED_FRTX) |
658 | chunk->fast_retransmit = SCTP_DONT_FRTX; |
659 | |
660 | q->empty = 0; |
661 | break; |
662 | } |
663 | |
664 | /* Set the timer if there were no errors */ |
665 | if (!error && !timer) |
666 | timer = 1; |
667 | |
668 | if (done) |
669 | break; |
670 | } |
671 | |
672 | /* If we are here due to a retransmit timeout or a fast |
673 | * retransmit and if there are any chunks left in the retransmit |
674 | * queue that could not fit in the PMTU sized packet, they need |
675 | * to be marked as ineligible for a subsequent fast retransmit. |
676 | */ |
677 | if (rtx_timeout || fast_rtx) { |
678 | list_for_each_entry(chunk1, lqueue, transmitted_list) { |
679 | if (chunk1->fast_retransmit == SCTP_NEED_FRTX) |
680 | chunk1->fast_retransmit = SCTP_DONT_FRTX; |
681 | } |
682 | } |
683 | |
684 | *start_timer = timer; |
685 | |
686 | /* Clear fast retransmit hint */ |
687 | if (fast_rtx) |
688 | q->fast_rtx = 0; |
689 | |
690 | return error; |
691 | } |
692 | |
693 | /* Cork the outqueue so queued chunks are really queued. */ |
694 | int sctp_outq_uncork(struct sctp_outq *q) |
695 | { |
696 | int error = 0; |
697 | if (q->cork) |
698 | q->cork = 0; |
699 | error = sctp_outq_flush(q, 0); |
700 | return error; |
701 | } |
702 | |
703 | |
704 | /* |
705 | * Try to flush an outqueue. |
706 | * |
707 | * Description: Send everything in q which we legally can, subject to |
708 | * congestion limitations. |
709 | * * Note: This function can be called from multiple contexts so appropriate |
710 | * locking concerns must be made. Today we use the sock lock to protect |
711 | * this function. |
712 | */ |
713 | static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout) |
714 | { |
715 | struct sctp_packet *packet; |
716 | struct sctp_packet singleton; |
717 | struct sctp_association *asoc = q->asoc; |
718 | __u16 sport = asoc->base.bind_addr.port; |
719 | __u16 dport = asoc->peer.port; |
720 | __u32 vtag = asoc->peer.i.init_tag; |
721 | struct sctp_transport *transport = NULL; |
722 | struct sctp_transport *new_transport; |
723 | struct sctp_chunk *chunk, *tmp; |
724 | sctp_xmit_t status; |
725 | int error = 0; |
726 | int start_timer = 0; |
727 | int one_packet = 0; |
728 | |
729 | /* These transports have chunks to send. */ |
730 | struct list_head transport_list; |
731 | struct list_head *ltransport; |
732 | |
733 | INIT_LIST_HEAD(&transport_list); |
734 | packet = NULL; |
735 | |
736 | /* |
737 | * 6.10 Bundling |
738 | * ... |
739 | * When bundling control chunks with DATA chunks, an |
740 | * endpoint MUST place control chunks first in the outbound |
741 | * SCTP packet. The transmitter MUST transmit DATA chunks |
742 | * within a SCTP packet in increasing order of TSN. |
743 | * ... |
744 | */ |
745 | |
746 | list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) { |
747 | list_del_init(&chunk->list); |
748 | |
749 | /* Pick the right transport to use. */ |
750 | new_transport = chunk->transport; |
751 | |
752 | if (!new_transport) { |
753 | /* |
754 | * If we have a prior transport pointer, see if |
755 | * the destination address of the chunk |
756 | * matches the destination address of the |
757 | * current transport. If not a match, then |
758 | * try to look up the transport with a given |
759 | * destination address. We do this because |
760 | * after processing ASCONFs, we may have new |
761 | * transports created. |
762 | */ |
763 | if (transport && |
764 | sctp_cmp_addr_exact(&chunk->dest, |
765 | &transport->ipaddr)) |
766 | new_transport = transport; |
767 | else |
768 | new_transport = sctp_assoc_lookup_paddr(asoc, |
769 | &chunk->dest); |
770 | |
771 | /* if we still don't have a new transport, then |
772 | * use the current active path. |
773 | */ |
774 | if (!new_transport) |
775 | new_transport = asoc->peer.active_path; |
776 | } else if ((new_transport->state == SCTP_INACTIVE) || |
777 | (new_transport->state == SCTP_UNCONFIRMED)) { |
778 | /* If the chunk is Heartbeat or Heartbeat Ack, |
779 | * send it to chunk->transport, even if it's |
780 | * inactive. |
781 | * |
782 | * 3.3.6 Heartbeat Acknowledgement: |
783 | * ... |
784 | * A HEARTBEAT ACK is always sent to the source IP |
785 | * address of the IP datagram containing the |
786 | * HEARTBEAT chunk to which this ack is responding. |
787 | * ... |
788 | * |
789 | * ASCONF_ACKs also must be sent to the source. |
790 | */ |
791 | if (chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT && |
792 | chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT_ACK && |
793 | chunk->chunk_hdr->type != SCTP_CID_ASCONF_ACK) |
794 | new_transport = asoc->peer.active_path; |
795 | } |
796 | |
797 | /* Are we switching transports? |
798 | * Take care of transport locks. |
799 | */ |
800 | if (new_transport != transport) { |
801 | transport = new_transport; |
802 | if (list_empty(&transport->send_ready)) { |
803 | list_add_tail(&transport->send_ready, |
804 | &transport_list); |
805 | } |
806 | packet = &transport->packet; |
807 | sctp_packet_config(packet, vtag, |
808 | asoc->peer.ecn_capable); |
809 | } |
810 | |
811 | switch (chunk->chunk_hdr->type) { |
812 | /* |
813 | * 6.10 Bundling |
814 | * ... |
815 | * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN |
816 | * COMPLETE with any other chunks. [Send them immediately.] |
817 | */ |
818 | case SCTP_CID_INIT: |
819 | case SCTP_CID_INIT_ACK: |
820 | case SCTP_CID_SHUTDOWN_COMPLETE: |
821 | sctp_packet_init(&singleton, transport, sport, dport); |
822 | sctp_packet_config(&singleton, vtag, 0); |
823 | sctp_packet_append_chunk(&singleton, chunk); |
824 | error = sctp_packet_transmit(&singleton); |
825 | if (error < 0) |
826 | return error; |
827 | break; |
828 | |
829 | case SCTP_CID_ABORT: |
830 | if (sctp_test_T_bit(chunk)) { |
831 | packet->vtag = asoc->c.my_vtag; |
832 | } |
833 | /* The following chunks are "response" chunks, i.e. |
834 | * they are generated in response to something we |
835 | * received. If we are sending these, then we can |
836 | * send only 1 packet containing these chunks. |
837 | */ |
838 | case SCTP_CID_HEARTBEAT_ACK: |
839 | case SCTP_CID_SHUTDOWN_ACK: |
840 | case SCTP_CID_COOKIE_ACK: |
841 | case SCTP_CID_COOKIE_ECHO: |
842 | case SCTP_CID_ERROR: |
843 | case SCTP_CID_ECN_CWR: |
844 | case SCTP_CID_ASCONF_ACK: |
845 | one_packet = 1; |
846 | /* Fall throught */ |
847 | |
848 | case SCTP_CID_SACK: |
849 | case SCTP_CID_HEARTBEAT: |
850 | case SCTP_CID_SHUTDOWN: |
851 | case SCTP_CID_ECN_ECNE: |
852 | case SCTP_CID_ASCONF: |
853 | case SCTP_CID_FWD_TSN: |
854 | status = sctp_packet_transmit_chunk(packet, chunk, |
855 | one_packet); |
856 | if (status != SCTP_XMIT_OK) { |
857 | /* put the chunk back */ |
858 | list_add(&chunk->list, &q->control_chunk_list); |
859 | } else if (chunk->chunk_hdr->type == SCTP_CID_FWD_TSN) { |
860 | /* PR-SCTP C5) If a FORWARD TSN is sent, the |
861 | * sender MUST assure that at least one T3-rtx |
862 | * timer is running. |
863 | */ |
864 | sctp_transport_reset_timers(transport); |
865 | } |
866 | break; |
867 | |
868 | default: |
869 | /* We built a chunk with an illegal type! */ |
870 | BUG(); |
871 | } |
872 | } |
873 | |
874 | /* Is it OK to send data chunks? */ |
875 | switch (asoc->state) { |
876 | case SCTP_STATE_COOKIE_ECHOED: |
877 | /* Only allow bundling when this packet has a COOKIE-ECHO |
878 | * chunk. |
879 | */ |
880 | if (!packet || !packet->has_cookie_echo) |
881 | break; |
882 | |
883 | /* fallthru */ |
884 | case SCTP_STATE_ESTABLISHED: |
885 | case SCTP_STATE_SHUTDOWN_PENDING: |
886 | case SCTP_STATE_SHUTDOWN_RECEIVED: |
887 | /* |
888 | * RFC 2960 6.1 Transmission of DATA Chunks |
889 | * |
890 | * C) When the time comes for the sender to transmit, |
891 | * before sending new DATA chunks, the sender MUST |
892 | * first transmit any outstanding DATA chunks which |
893 | * are marked for retransmission (limited by the |
894 | * current cwnd). |
895 | */ |
896 | if (!list_empty(&q->retransmit)) { |
897 | if (transport == asoc->peer.retran_path) |
898 | goto retran; |
899 | |
900 | /* Switch transports & prepare the packet. */ |
901 | |
902 | transport = asoc->peer.retran_path; |
903 | |
904 | if (list_empty(&transport->send_ready)) { |
905 | list_add_tail(&transport->send_ready, |
906 | &transport_list); |
907 | } |
908 | |
909 | packet = &transport->packet; |
910 | sctp_packet_config(packet, vtag, |
911 | asoc->peer.ecn_capable); |
912 | retran: |
913 | error = sctp_outq_flush_rtx(q, packet, |
914 | rtx_timeout, &start_timer); |
915 | |
916 | if (start_timer) |
917 | sctp_transport_reset_timers(transport); |
918 | |
919 | /* This can happen on COOKIE-ECHO resend. Only |
920 | * one chunk can get bundled with a COOKIE-ECHO. |
921 | */ |
922 | if (packet->has_cookie_echo) |
923 | goto sctp_flush_out; |
924 | |
925 | /* Don't send new data if there is still data |
926 | * waiting to retransmit. |
927 | */ |
928 | if (!list_empty(&q->retransmit)) |
929 | goto sctp_flush_out; |
930 | } |
931 | |
932 | /* Apply Max.Burst limitation to the current transport in |
933 | * case it will be used for new data. We are going to |
934 | * rest it before we return, but we want to apply the limit |
935 | * to the currently queued data. |
936 | */ |
937 | if (transport) |
938 | sctp_transport_burst_limited(transport); |
939 | |
940 | /* Finally, transmit new packets. */ |
941 | while ((chunk = sctp_outq_dequeue_data(q)) != NULL) { |
942 | /* RFC 2960 6.5 Every DATA chunk MUST carry a valid |
943 | * stream identifier. |
944 | */ |
945 | if (chunk->sinfo.sinfo_stream >= |
946 | asoc->c.sinit_num_ostreams) { |
947 | |
948 | /* Mark as failed send. */ |
949 | sctp_chunk_fail(chunk, SCTP_ERROR_INV_STRM); |
950 | sctp_chunk_free(chunk); |
951 | continue; |
952 | } |
953 | |
954 | /* Has this chunk expired? */ |
955 | if (sctp_chunk_abandoned(chunk)) { |
956 | sctp_chunk_fail(chunk, 0); |
957 | sctp_chunk_free(chunk); |
958 | continue; |
959 | } |
960 | |
961 | /* If there is a specified transport, use it. |
962 | * Otherwise, we want to use the active path. |
963 | */ |
964 | new_transport = chunk->transport; |
965 | if (!new_transport || |
966 | ((new_transport->state == SCTP_INACTIVE) || |
967 | (new_transport->state == SCTP_UNCONFIRMED))) |
968 | new_transport = asoc->peer.active_path; |
969 | |
970 | /* Change packets if necessary. */ |
971 | if (new_transport != transport) { |
972 | transport = new_transport; |
973 | |
974 | /* Schedule to have this transport's |
975 | * packet flushed. |
976 | */ |
977 | if (list_empty(&transport->send_ready)) { |
978 | list_add_tail(&transport->send_ready, |
979 | &transport_list); |
980 | } |
981 | |
982 | packet = &transport->packet; |
983 | sctp_packet_config(packet, vtag, |
984 | asoc->peer.ecn_capable); |
985 | /* We've switched transports, so apply the |
986 | * Burst limit to the new transport. |
987 | */ |
988 | sctp_transport_burst_limited(transport); |
989 | } |
990 | |
991 | SCTP_DEBUG_PRINTK("sctp_outq_flush(%p, %p[%s]), ", |
992 | q, chunk, |
993 | chunk && chunk->chunk_hdr ? |
994 | sctp_cname(SCTP_ST_CHUNK( |
995 | chunk->chunk_hdr->type)) |
996 | : "Illegal Chunk"); |
997 | |
998 | SCTP_DEBUG_PRINTK("TX TSN 0x%x skb->head " |
999 | "%p skb->users %d.\n", |
1000 | ntohl(chunk->subh.data_hdr->tsn), |
1001 | chunk->skb ?chunk->skb->head : NULL, |
1002 | chunk->skb ? |
1003 | atomic_read(&chunk->skb->users) : -1); |
1004 | |
1005 | /* Add the chunk to the packet. */ |
1006 | status = sctp_packet_transmit_chunk(packet, chunk, 0); |
1007 | |
1008 | switch (status) { |
1009 | case SCTP_XMIT_PMTU_FULL: |
1010 | case SCTP_XMIT_RWND_FULL: |
1011 | case SCTP_XMIT_NAGLE_DELAY: |
1012 | /* We could not append this chunk, so put |
1013 | * the chunk back on the output queue. |
1014 | */ |
1015 | SCTP_DEBUG_PRINTK("sctp_outq_flush: could " |
1016 | "not transmit TSN: 0x%x, status: %d\n", |
1017 | ntohl(chunk->subh.data_hdr->tsn), |
1018 | status); |
1019 | sctp_outq_head_data(q, chunk); |
1020 | goto sctp_flush_out; |
1021 | break; |
1022 | |
1023 | case SCTP_XMIT_OK: |
1024 | /* The sender is in the SHUTDOWN-PENDING state, |
1025 | * The sender MAY set the I-bit in the DATA |
1026 | * chunk header. |
1027 | */ |
1028 | if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING) |
1029 | chunk->chunk_hdr->flags |= SCTP_DATA_SACK_IMM; |
1030 | |
1031 | break; |
1032 | |
1033 | default: |
1034 | BUG(); |
1035 | } |
1036 | |
1037 | /* BUG: We assume that the sctp_packet_transmit() |
1038 | * call below will succeed all the time and add the |
1039 | * chunk to the transmitted list and restart the |
1040 | * timers. |
1041 | * It is possible that the call can fail under OOM |
1042 | * conditions. |
1043 | * |
1044 | * Is this really a problem? Won't this behave |
1045 | * like a lost TSN? |
1046 | */ |
1047 | list_add_tail(&chunk->transmitted_list, |
1048 | &transport->transmitted); |
1049 | |
1050 | sctp_transport_reset_timers(transport); |
1051 | |
1052 | q->empty = 0; |
1053 | |
1054 | /* Only let one DATA chunk get bundled with a |
1055 | * COOKIE-ECHO chunk. |
1056 | */ |
1057 | if (packet->has_cookie_echo) |
1058 | goto sctp_flush_out; |
1059 | } |
1060 | break; |
1061 | |
1062 | default: |
1063 | /* Do nothing. */ |
1064 | break; |
1065 | } |
1066 | |
1067 | sctp_flush_out: |
1068 | |
1069 | /* Before returning, examine all the transports touched in |
1070 | * this call. Right now, we bluntly force clear all the |
1071 | * transports. Things might change after we implement Nagle. |
1072 | * But such an examination is still required. |
1073 | * |
1074 | * --xguo |
1075 | */ |
1076 | while ((ltransport = sctp_list_dequeue(&transport_list)) != NULL ) { |
1077 | struct sctp_transport *t = list_entry(ltransport, |
1078 | struct sctp_transport, |
1079 | send_ready); |
1080 | packet = &t->packet; |
1081 | if (!sctp_packet_empty(packet)) |
1082 | error = sctp_packet_transmit(packet); |
1083 | |
1084 | /* Clear the burst limited state, if any */ |
1085 | sctp_transport_burst_reset(t); |
1086 | } |
1087 | |
1088 | return error; |
1089 | } |
1090 | |
1091 | /* Update unack_data based on the incoming SACK chunk */ |
1092 | static void sctp_sack_update_unack_data(struct sctp_association *assoc, |
1093 | struct sctp_sackhdr *sack) |
1094 | { |
1095 | sctp_sack_variable_t *frags; |
1096 | __u16 unack_data; |
1097 | int i; |
1098 | |
1099 | unack_data = assoc->next_tsn - assoc->ctsn_ack_point - 1; |
1100 | |
1101 | frags = sack->variable; |
1102 | for (i = 0; i < ntohs(sack->num_gap_ack_blocks); i++) { |
1103 | unack_data -= ((ntohs(frags[i].gab.end) - |
1104 | ntohs(frags[i].gab.start) + 1)); |
1105 | } |
1106 | |
1107 | assoc->unack_data = unack_data; |
1108 | } |
1109 | |
1110 | /* This is where we REALLY process a SACK. |
1111 | * |
1112 | * Process the SACK against the outqueue. Mostly, this just frees |
1113 | * things off the transmitted queue. |
1114 | */ |
1115 | int sctp_outq_sack(struct sctp_outq *q, struct sctp_sackhdr *sack) |
1116 | { |
1117 | struct sctp_association *asoc = q->asoc; |
1118 | struct sctp_transport *transport; |
1119 | struct sctp_chunk *tchunk = NULL; |
1120 | struct list_head *lchunk, *transport_list, *temp; |
1121 | sctp_sack_variable_t *frags = sack->variable; |
1122 | __u32 sack_ctsn, ctsn, tsn; |
1123 | __u32 highest_tsn, highest_new_tsn; |
1124 | __u32 sack_a_rwnd; |
1125 | unsigned outstanding; |
1126 | struct sctp_transport *primary = asoc->peer.primary_path; |
1127 | int count_of_newacks = 0; |
1128 | int gap_ack_blocks; |
1129 | u8 accum_moved = 0; |
1130 | |
1131 | /* Grab the association's destination address list. */ |
1132 | transport_list = &asoc->peer.transport_addr_list; |
1133 | |
1134 | sack_ctsn = ntohl(sack->cum_tsn_ack); |
1135 | gap_ack_blocks = ntohs(sack->num_gap_ack_blocks); |
1136 | /* |
1137 | * SFR-CACC algorithm: |
1138 | * On receipt of a SACK the sender SHOULD execute the |
1139 | * following statements. |
1140 | * |
1141 | * 1) If the cumulative ack in the SACK passes next tsn_at_change |
1142 | * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be |
1143 | * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for |
1144 | * all destinations. |
1145 | * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE |
1146 | * is set the receiver of the SACK MUST take the following actions: |
1147 | * |
1148 | * A) Initialize the cacc_saw_newack to 0 for all destination |
1149 | * addresses. |
1150 | * |
1151 | * Only bother if changeover_active is set. Otherwise, this is |
1152 | * totally suboptimal to do on every SACK. |
1153 | */ |
1154 | if (primary->cacc.changeover_active) { |
1155 | u8 clear_cycling = 0; |
1156 | |
1157 | if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) { |
1158 | primary->cacc.changeover_active = 0; |
1159 | clear_cycling = 1; |
1160 | } |
1161 | |
1162 | if (clear_cycling || gap_ack_blocks) { |
1163 | list_for_each_entry(transport, transport_list, |
1164 | transports) { |
1165 | if (clear_cycling) |
1166 | transport->cacc.cycling_changeover = 0; |
1167 | if (gap_ack_blocks) |
1168 | transport->cacc.cacc_saw_newack = 0; |
1169 | } |
1170 | } |
1171 | } |
1172 | |
1173 | /* Get the highest TSN in the sack. */ |
1174 | highest_tsn = sack_ctsn; |
1175 | if (gap_ack_blocks) |
1176 | highest_tsn += ntohs(frags[gap_ack_blocks - 1].gab.end); |
1177 | |
1178 | if (TSN_lt(asoc->highest_sacked, highest_tsn)) |
1179 | asoc->highest_sacked = highest_tsn; |
1180 | |
1181 | highest_new_tsn = sack_ctsn; |
1182 | |
1183 | /* Run through the retransmit queue. Credit bytes received |
1184 | * and free those chunks that we can. |
1185 | */ |
1186 | sctp_check_transmitted(q, &q->retransmit, NULL, sack, &highest_new_tsn); |
1187 | |
1188 | /* Run through the transmitted queue. |
1189 | * Credit bytes received and free those chunks which we can. |
1190 | * |
1191 | * This is a MASSIVE candidate for optimization. |
1192 | */ |
1193 | list_for_each_entry(transport, transport_list, transports) { |
1194 | sctp_check_transmitted(q, &transport->transmitted, |
1195 | transport, sack, &highest_new_tsn); |
1196 | /* |
1197 | * SFR-CACC algorithm: |
1198 | * C) Let count_of_newacks be the number of |
1199 | * destinations for which cacc_saw_newack is set. |
1200 | */ |
1201 | if (transport->cacc.cacc_saw_newack) |
1202 | count_of_newacks ++; |
1203 | } |
1204 | |
1205 | /* Move the Cumulative TSN Ack Point if appropriate. */ |
1206 | if (TSN_lt(asoc->ctsn_ack_point, sack_ctsn)) { |
1207 | asoc->ctsn_ack_point = sack_ctsn; |
1208 | accum_moved = 1; |
1209 | } |
1210 | |
1211 | if (gap_ack_blocks) { |
1212 | |
1213 | if (asoc->fast_recovery && accum_moved) |
1214 | highest_new_tsn = highest_tsn; |
1215 | |
1216 | list_for_each_entry(transport, transport_list, transports) |
1217 | sctp_mark_missing(q, &transport->transmitted, transport, |
1218 | highest_new_tsn, count_of_newacks); |
1219 | } |
1220 | |
1221 | /* Update unack_data field in the assoc. */ |
1222 | sctp_sack_update_unack_data(asoc, sack); |
1223 | |
1224 | ctsn = asoc->ctsn_ack_point; |
1225 | |
1226 | /* Throw away stuff rotting on the sack queue. */ |
1227 | list_for_each_safe(lchunk, temp, &q->sacked) { |
1228 | tchunk = list_entry(lchunk, struct sctp_chunk, |
1229 | transmitted_list); |
1230 | tsn = ntohl(tchunk->subh.data_hdr->tsn); |
1231 | if (TSN_lte(tsn, ctsn)) { |
1232 | list_del_init(&tchunk->transmitted_list); |
1233 | sctp_chunk_free(tchunk); |
1234 | } |
1235 | } |
1236 | |
1237 | /* ii) Set rwnd equal to the newly received a_rwnd minus the |
1238 | * number of bytes still outstanding after processing the |
1239 | * Cumulative TSN Ack and the Gap Ack Blocks. |
1240 | */ |
1241 | |
1242 | sack_a_rwnd = ntohl(sack->a_rwnd); |
1243 | outstanding = q->outstanding_bytes; |
1244 | |
1245 | if (outstanding < sack_a_rwnd) |
1246 | sack_a_rwnd -= outstanding; |
1247 | else |
1248 | sack_a_rwnd = 0; |
1249 | |
1250 | asoc->peer.rwnd = sack_a_rwnd; |
1251 | |
1252 | sctp_generate_fwdtsn(q, sack_ctsn); |
1253 | |
1254 | SCTP_DEBUG_PRINTK("%s: sack Cumulative TSN Ack is 0x%x.\n", |
1255 | __func__, sack_ctsn); |
1256 | SCTP_DEBUG_PRINTK("%s: Cumulative TSN Ack of association, " |
1257 | "%p is 0x%x. Adv peer ack point: 0x%x\n", |
1258 | __func__, asoc, ctsn, asoc->adv_peer_ack_point); |
1259 | |
1260 | /* See if all chunks are acked. |
1261 | * Make sure the empty queue handler will get run later. |
1262 | */ |
1263 | q->empty = (list_empty(&q->out_chunk_list) && |
1264 | list_empty(&q->retransmit)); |
1265 | if (!q->empty) |
1266 | goto finish; |
1267 | |
1268 | list_for_each_entry(transport, transport_list, transports) { |
1269 | q->empty = q->empty && list_empty(&transport->transmitted); |
1270 | if (!q->empty) |
1271 | goto finish; |
1272 | } |
1273 | |
1274 | SCTP_DEBUG_PRINTK("sack queue is empty.\n"); |
1275 | finish: |
1276 | return q->empty; |
1277 | } |
1278 | |
1279 | /* Is the outqueue empty? */ |
1280 | int sctp_outq_is_empty(const struct sctp_outq *q) |
1281 | { |
1282 | return q->empty; |
1283 | } |
1284 | |
1285 | /******************************************************************** |
1286 | * 2nd Level Abstractions |
1287 | ********************************************************************/ |
1288 | |
1289 | /* Go through a transport's transmitted list or the association's retransmit |
1290 | * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked. |
1291 | * The retransmit list will not have an associated transport. |
1292 | * |
1293 | * I added coherent debug information output. --xguo |
1294 | * |
1295 | * Instead of printing 'sacked' or 'kept' for each TSN on the |
1296 | * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5. |
1297 | * KEPT TSN6-TSN7, etc. |
1298 | */ |
1299 | static void sctp_check_transmitted(struct sctp_outq *q, |
1300 | struct list_head *transmitted_queue, |
1301 | struct sctp_transport *transport, |
1302 | struct sctp_sackhdr *sack, |
1303 | __u32 *highest_new_tsn_in_sack) |
1304 | { |
1305 | struct list_head *lchunk; |
1306 | struct sctp_chunk *tchunk; |
1307 | struct list_head tlist; |
1308 | __u32 tsn; |
1309 | __u32 sack_ctsn; |
1310 | __u32 rtt; |
1311 | __u8 restart_timer = 0; |
1312 | int bytes_acked = 0; |
1313 | int migrate_bytes = 0; |
1314 | |
1315 | /* These state variables are for coherent debug output. --xguo */ |
1316 | |
1317 | #if SCTP_DEBUG |
1318 | __u32 dbg_ack_tsn = 0; /* An ACKed TSN range starts here... */ |
1319 | __u32 dbg_last_ack_tsn = 0; /* ...and finishes here. */ |
1320 | __u32 dbg_kept_tsn = 0; /* An un-ACKed range starts here... */ |
1321 | __u32 dbg_last_kept_tsn = 0; /* ...and finishes here. */ |
1322 | |
1323 | /* 0 : The last TSN was ACKed. |
1324 | * 1 : The last TSN was NOT ACKed (i.e. KEPT). |
1325 | * -1: We need to initialize. |
1326 | */ |
1327 | int dbg_prt_state = -1; |
1328 | #endif /* SCTP_DEBUG */ |
1329 | |
1330 | sack_ctsn = ntohl(sack->cum_tsn_ack); |
1331 | |
1332 | INIT_LIST_HEAD(&tlist); |
1333 | |
1334 | /* The while loop will skip empty transmitted queues. */ |
1335 | while (NULL != (lchunk = sctp_list_dequeue(transmitted_queue))) { |
1336 | tchunk = list_entry(lchunk, struct sctp_chunk, |
1337 | transmitted_list); |
1338 | |
1339 | if (sctp_chunk_abandoned(tchunk)) { |
1340 | /* Move the chunk to abandoned list. */ |
1341 | sctp_insert_list(&q->abandoned, lchunk); |
1342 | |
1343 | /* If this chunk has not been acked, stop |
1344 | * considering it as 'outstanding'. |
1345 | */ |
1346 | if (!tchunk->tsn_gap_acked) { |
1347 | if (tchunk->transport) |
1348 | tchunk->transport->flight_size -= |
1349 | sctp_data_size(tchunk); |
1350 | q->outstanding_bytes -= sctp_data_size(tchunk); |
1351 | } |
1352 | continue; |
1353 | } |
1354 | |
1355 | tsn = ntohl(tchunk->subh.data_hdr->tsn); |
1356 | if (sctp_acked(sack, tsn)) { |
1357 | /* If this queue is the retransmit queue, the |
1358 | * retransmit timer has already reclaimed |
1359 | * the outstanding bytes for this chunk, so only |
1360 | * count bytes associated with a transport. |
1361 | */ |
1362 | if (transport) { |
1363 | /* If this chunk is being used for RTT |
1364 | * measurement, calculate the RTT and update |
1365 | * the RTO using this value. |
1366 | * |
1367 | * 6.3.1 C5) Karn's algorithm: RTT measurements |
1368 | * MUST NOT be made using packets that were |
1369 | * retransmitted (and thus for which it is |
1370 | * ambiguous whether the reply was for the |
1371 | * first instance of the packet or a later |
1372 | * instance). |
1373 | */ |
1374 | if (!tchunk->tsn_gap_acked && |
1375 | tchunk->rtt_in_progress) { |
1376 | tchunk->rtt_in_progress = 0; |
1377 | rtt = jiffies - tchunk->sent_at; |
1378 | sctp_transport_update_rto(transport, |
1379 | rtt); |
1380 | } |
1381 | } |
1382 | |
1383 | /* If the chunk hasn't been marked as ACKED, |
1384 | * mark it and account bytes_acked if the |
1385 | * chunk had a valid transport (it will not |
1386 | * have a transport if ASCONF had deleted it |
1387 | * while DATA was outstanding). |
1388 | */ |
1389 | if (!tchunk->tsn_gap_acked) { |
1390 | tchunk->tsn_gap_acked = 1; |
1391 | *highest_new_tsn_in_sack = tsn; |
1392 | bytes_acked += sctp_data_size(tchunk); |
1393 | if (!tchunk->transport) |
1394 | migrate_bytes += sctp_data_size(tchunk); |
1395 | } |
1396 | |
1397 | if (TSN_lte(tsn, sack_ctsn)) { |
1398 | /* RFC 2960 6.3.2 Retransmission Timer Rules |
1399 | * |
1400 | * R3) Whenever a SACK is received |
1401 | * that acknowledges the DATA chunk |
1402 | * with the earliest outstanding TSN |
1403 | * for that address, restart T3-rtx |
1404 | * timer for that address with its |
1405 | * current RTO. |
1406 | */ |
1407 | restart_timer = 1; |
1408 | |
1409 | if (!tchunk->tsn_gap_acked) { |
1410 | /* |
1411 | * SFR-CACC algorithm: |
1412 | * 2) If the SACK contains gap acks |
1413 | * and the flag CHANGEOVER_ACTIVE is |
1414 | * set the receiver of the SACK MUST |
1415 | * take the following action: |
1416 | * |
1417 | * B) For each TSN t being acked that |
1418 | * has not been acked in any SACK so |
1419 | * far, set cacc_saw_newack to 1 for |
1420 | * the destination that the TSN was |
1421 | * sent to. |
1422 | */ |
1423 | if (transport && |
1424 | sack->num_gap_ack_blocks && |
1425 | q->asoc->peer.primary_path->cacc. |
1426 | changeover_active) |
1427 | transport->cacc.cacc_saw_newack |
1428 | = 1; |
1429 | } |
1430 | |
1431 | list_add_tail(&tchunk->transmitted_list, |
1432 | &q->sacked); |
1433 | } else { |
1434 | /* RFC2960 7.2.4, sctpimpguide-05 2.8.2 |
1435 | * M2) Each time a SACK arrives reporting |
1436 | * 'Stray DATA chunk(s)' record the highest TSN |
1437 | * reported as newly acknowledged, call this |
1438 | * value 'HighestTSNinSack'. A newly |
1439 | * acknowledged DATA chunk is one not |
1440 | * previously acknowledged in a SACK. |
1441 | * |
1442 | * When the SCTP sender of data receives a SACK |
1443 | * chunk that acknowledges, for the first time, |
1444 | * the receipt of a DATA chunk, all the still |
1445 | * unacknowledged DATA chunks whose TSN is |
1446 | * older than that newly acknowledged DATA |
1447 | * chunk, are qualified as 'Stray DATA chunks'. |
1448 | */ |
1449 | list_add_tail(lchunk, &tlist); |
1450 | } |
1451 | |
1452 | #if SCTP_DEBUG |
1453 | switch (dbg_prt_state) { |
1454 | case 0: /* last TSN was ACKed */ |
1455 | if (dbg_last_ack_tsn + 1 == tsn) { |
1456 | /* This TSN belongs to the |
1457 | * current ACK range. |
1458 | */ |
1459 | break; |
1460 | } |
1461 | |
1462 | if (dbg_last_ack_tsn != dbg_ack_tsn) { |
1463 | /* Display the end of the |
1464 | * current range. |
1465 | */ |
1466 | SCTP_DEBUG_PRINTK("-%08x", |
1467 | dbg_last_ack_tsn); |
1468 | } |
1469 | |
1470 | /* Start a new range. */ |
1471 | SCTP_DEBUG_PRINTK(",%08x", tsn); |
1472 | dbg_ack_tsn = tsn; |
1473 | break; |
1474 | |
1475 | case 1: /* The last TSN was NOT ACKed. */ |
1476 | if (dbg_last_kept_tsn != dbg_kept_tsn) { |
1477 | /* Display the end of current range. */ |
1478 | SCTP_DEBUG_PRINTK("-%08x", |
1479 | dbg_last_kept_tsn); |
1480 | } |
1481 | |
1482 | SCTP_DEBUG_PRINTK("\n"); |
1483 | |
1484 | /* FALL THROUGH... */ |
1485 | default: |
1486 | /* This is the first-ever TSN we examined. */ |
1487 | /* Start a new range of ACK-ed TSNs. */ |
1488 | SCTP_DEBUG_PRINTK("ACKed: %08x", tsn); |
1489 | dbg_prt_state = 0; |
1490 | dbg_ack_tsn = tsn; |
1491 | } |
1492 | |
1493 | dbg_last_ack_tsn = tsn; |
1494 | #endif /* SCTP_DEBUG */ |
1495 | |
1496 | } else { |
1497 | if (tchunk->tsn_gap_acked) { |
1498 | SCTP_DEBUG_PRINTK("%s: Receiver reneged on " |
1499 | "data TSN: 0x%x\n", |
1500 | __func__, |
1501 | tsn); |
1502 | tchunk->tsn_gap_acked = 0; |
1503 | |
1504 | if (tchunk->transport) |
1505 | bytes_acked -= sctp_data_size(tchunk); |
1506 | |
1507 | /* RFC 2960 6.3.2 Retransmission Timer Rules |
1508 | * |
1509 | * R4) Whenever a SACK is received missing a |
1510 | * TSN that was previously acknowledged via a |
1511 | * Gap Ack Block, start T3-rtx for the |
1512 | * destination address to which the DATA |
1513 | * chunk was originally |
1514 | * transmitted if it is not already running. |
1515 | */ |
1516 | restart_timer = 1; |
1517 | } |
1518 | |
1519 | list_add_tail(lchunk, &tlist); |
1520 | |
1521 | #if SCTP_DEBUG |
1522 | /* See the above comments on ACK-ed TSNs. */ |
1523 | switch (dbg_prt_state) { |
1524 | case 1: |
1525 | if (dbg_last_kept_tsn + 1 == tsn) |
1526 | break; |
1527 | |
1528 | if (dbg_last_kept_tsn != dbg_kept_tsn) |
1529 | SCTP_DEBUG_PRINTK("-%08x", |
1530 | dbg_last_kept_tsn); |
1531 | |
1532 | SCTP_DEBUG_PRINTK(",%08x", tsn); |
1533 | dbg_kept_tsn = tsn; |
1534 | break; |
1535 | |
1536 | case 0: |
1537 | if (dbg_last_ack_tsn != dbg_ack_tsn) |
1538 | SCTP_DEBUG_PRINTK("-%08x", |
1539 | dbg_last_ack_tsn); |
1540 | SCTP_DEBUG_PRINTK("\n"); |
1541 | |
1542 | /* FALL THROUGH... */ |
1543 | default: |
1544 | SCTP_DEBUG_PRINTK("KEPT: %08x",tsn); |
1545 | dbg_prt_state = 1; |
1546 | dbg_kept_tsn = tsn; |
1547 | } |
1548 | |
1549 | dbg_last_kept_tsn = tsn; |
1550 | #endif /* SCTP_DEBUG */ |
1551 | } |
1552 | } |
1553 | |
1554 | #if SCTP_DEBUG |
1555 | /* Finish off the last range, displaying its ending TSN. */ |
1556 | switch (dbg_prt_state) { |
1557 | case 0: |
1558 | if (dbg_last_ack_tsn != dbg_ack_tsn) { |
1559 | SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_ack_tsn); |
1560 | } else { |
1561 | SCTP_DEBUG_PRINTK("\n"); |
1562 | } |
1563 | break; |
1564 | |
1565 | case 1: |
1566 | if (dbg_last_kept_tsn != dbg_kept_tsn) { |
1567 | SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_kept_tsn); |
1568 | } else { |
1569 | SCTP_DEBUG_PRINTK("\n"); |
1570 | } |
1571 | } |
1572 | #endif /* SCTP_DEBUG */ |
1573 | if (transport) { |
1574 | if (bytes_acked) { |
1575 | /* We may have counted DATA that was migrated |
1576 | * to this transport due to DEL-IP operation. |
1577 | * Subtract those bytes, since the were never |
1578 | * send on this transport and shouldn't be |
1579 | * credited to this transport. |
1580 | */ |
1581 | bytes_acked -= migrate_bytes; |
1582 | |
1583 | /* 8.2. When an outstanding TSN is acknowledged, |
1584 | * the endpoint shall clear the error counter of |
1585 | * the destination transport address to which the |
1586 | * DATA chunk was last sent. |
1587 | * The association's overall error counter is |
1588 | * also cleared. |
1589 | */ |
1590 | transport->error_count = 0; |
1591 | transport->asoc->overall_error_count = 0; |
1592 | |
1593 | /* Mark the destination transport address as |
1594 | * active if it is not so marked. |
1595 | */ |
1596 | if ((transport->state == SCTP_INACTIVE) || |
1597 | (transport->state == SCTP_UNCONFIRMED)) { |
1598 | sctp_assoc_control_transport( |
1599 | transport->asoc, |
1600 | transport, |
1601 | SCTP_TRANSPORT_UP, |
1602 | SCTP_RECEIVED_SACK); |
1603 | } |
1604 | |
1605 | sctp_transport_raise_cwnd(transport, sack_ctsn, |
1606 | bytes_acked); |
1607 | |
1608 | transport->flight_size -= bytes_acked; |
1609 | if (transport->flight_size == 0) |
1610 | transport->partial_bytes_acked = 0; |
1611 | q->outstanding_bytes -= bytes_acked + migrate_bytes; |
1612 | } else { |
1613 | /* RFC 2960 6.1, sctpimpguide-06 2.15.2 |
1614 | * When a sender is doing zero window probing, it |
1615 | * should not timeout the association if it continues |
1616 | * to receive new packets from the receiver. The |
1617 | * reason is that the receiver MAY keep its window |
1618 | * closed for an indefinite time. |
1619 | * A sender is doing zero window probing when the |
1620 | * receiver's advertised window is zero, and there is |
1621 | * only one data chunk in flight to the receiver. |
1622 | */ |
1623 | if (!q->asoc->peer.rwnd && |
1624 | !list_empty(&tlist) && |
1625 | (sack_ctsn+2 == q->asoc->next_tsn)) { |
1626 | SCTP_DEBUG_PRINTK("%s: SACK received for zero " |
1627 | "window probe: %u\n", |
1628 | __func__, sack_ctsn); |
1629 | q->asoc->overall_error_count = 0; |
1630 | transport->error_count = 0; |
1631 | } |
1632 | } |
1633 | |
1634 | /* RFC 2960 6.3.2 Retransmission Timer Rules |
1635 | * |
1636 | * R2) Whenever all outstanding data sent to an address have |
1637 | * been acknowledged, turn off the T3-rtx timer of that |
1638 | * address. |
1639 | */ |
1640 | if (!transport->flight_size) { |
1641 | if (timer_pending(&transport->T3_rtx_timer) && |
1642 | del_timer(&transport->T3_rtx_timer)) { |
1643 | sctp_transport_put(transport); |
1644 | } |
1645 | } else if (restart_timer) { |
1646 | if (!mod_timer(&transport->T3_rtx_timer, |
1647 | jiffies + transport->rto)) |
1648 | sctp_transport_hold(transport); |
1649 | } |
1650 | } |
1651 | |
1652 | list_splice(&tlist, transmitted_queue); |
1653 | } |
1654 | |
1655 | /* Mark chunks as missing and consequently may get retransmitted. */ |
1656 | static void sctp_mark_missing(struct sctp_outq *q, |
1657 | struct list_head *transmitted_queue, |
1658 | struct sctp_transport *transport, |
1659 | __u32 highest_new_tsn_in_sack, |
1660 | int count_of_newacks) |
1661 | { |
1662 | struct sctp_chunk *chunk; |
1663 | __u32 tsn; |
1664 | char do_fast_retransmit = 0; |
1665 | struct sctp_association *asoc = q->asoc; |
1666 | struct sctp_transport *primary = asoc->peer.primary_path; |
1667 | |
1668 | list_for_each_entry(chunk, transmitted_queue, transmitted_list) { |
1669 | |
1670 | tsn = ntohl(chunk->subh.data_hdr->tsn); |
1671 | |
1672 | /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all |
1673 | * 'Unacknowledged TSN's', if the TSN number of an |
1674 | * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack' |
1675 | * value, increment the 'TSN.Missing.Report' count on that |
1676 | * chunk if it has NOT been fast retransmitted or marked for |
1677 | * fast retransmit already. |
1678 | */ |
1679 | if (chunk->fast_retransmit == SCTP_CAN_FRTX && |
1680 | !chunk->tsn_gap_acked && |
1681 | TSN_lt(tsn, highest_new_tsn_in_sack)) { |
1682 | |
1683 | /* SFR-CACC may require us to skip marking |
1684 | * this chunk as missing. |
1685 | */ |
1686 | if (!transport || !sctp_cacc_skip(primary, transport, |
1687 | count_of_newacks, tsn)) { |
1688 | chunk->tsn_missing_report++; |
1689 | |
1690 | SCTP_DEBUG_PRINTK( |
1691 | "%s: TSN 0x%x missing counter: %d\n", |
1692 | __func__, tsn, |
1693 | chunk->tsn_missing_report); |
1694 | } |
1695 | } |
1696 | /* |
1697 | * M4) If any DATA chunk is found to have a |
1698 | * 'TSN.Missing.Report' |
1699 | * value larger than or equal to 3, mark that chunk for |
1700 | * retransmission and start the fast retransmit procedure. |
1701 | */ |
1702 | |
1703 | if (chunk->tsn_missing_report >= 3) { |
1704 | chunk->fast_retransmit = SCTP_NEED_FRTX; |
1705 | do_fast_retransmit = 1; |
1706 | } |
1707 | } |
1708 | |
1709 | if (transport) { |
1710 | if (do_fast_retransmit) |
1711 | sctp_retransmit(q, transport, SCTP_RTXR_FAST_RTX); |
1712 | |
1713 | SCTP_DEBUG_PRINTK("%s: transport: %p, cwnd: %d, " |
1714 | "ssthresh: %d, flight_size: %d, pba: %d\n", |
1715 | __func__, transport, transport->cwnd, |
1716 | transport->ssthresh, transport->flight_size, |
1717 | transport->partial_bytes_acked); |
1718 | } |
1719 | } |
1720 | |
1721 | /* Is the given TSN acked by this packet? */ |
1722 | static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn) |
1723 | { |
1724 | int i; |
1725 | sctp_sack_variable_t *frags; |
1726 | __u16 gap; |
1727 | __u32 ctsn = ntohl(sack->cum_tsn_ack); |
1728 | |
1729 | if (TSN_lte(tsn, ctsn)) |
1730 | goto pass; |
1731 | |
1732 | /* 3.3.4 Selective Acknowledgement (SACK) (3): |
1733 | * |
1734 | * Gap Ack Blocks: |
1735 | * These fields contain the Gap Ack Blocks. They are repeated |
1736 | * for each Gap Ack Block up to the number of Gap Ack Blocks |
1737 | * defined in the Number of Gap Ack Blocks field. All DATA |
1738 | * chunks with TSNs greater than or equal to (Cumulative TSN |
1739 | * Ack + Gap Ack Block Start) and less than or equal to |
1740 | * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack |
1741 | * Block are assumed to have been received correctly. |
1742 | */ |
1743 | |
1744 | frags = sack->variable; |
1745 | gap = tsn - ctsn; |
1746 | for (i = 0; i < ntohs(sack->num_gap_ack_blocks); ++i) { |
1747 | if (TSN_lte(ntohs(frags[i].gab.start), gap) && |
1748 | TSN_lte(gap, ntohs(frags[i].gab.end))) |
1749 | goto pass; |
1750 | } |
1751 | |
1752 | return 0; |
1753 | pass: |
1754 | return 1; |
1755 | } |
1756 | |
1757 | static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip *skiplist, |
1758 | int nskips, __be16 stream) |
1759 | { |
1760 | int i; |
1761 | |
1762 | for (i = 0; i < nskips; i++) { |
1763 | if (skiplist[i].stream == stream) |
1764 | return i; |
1765 | } |
1766 | return i; |
1767 | } |
1768 | |
1769 | /* Create and add a fwdtsn chunk to the outq's control queue if needed. */ |
1770 | static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 ctsn) |
1771 | { |
1772 | struct sctp_association *asoc = q->asoc; |
1773 | struct sctp_chunk *ftsn_chunk = NULL; |
1774 | struct sctp_fwdtsn_skip ftsn_skip_arr[10]; |
1775 | int nskips = 0; |
1776 | int skip_pos = 0; |
1777 | __u32 tsn; |
1778 | struct sctp_chunk *chunk; |
1779 | struct list_head *lchunk, *temp; |
1780 | |
1781 | if (!asoc->peer.prsctp_capable) |
1782 | return; |
1783 | |
1784 | /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the |
1785 | * received SACK. |
1786 | * |
1787 | * If (Advanced.Peer.Ack.Point < SackCumAck), then update |
1788 | * Advanced.Peer.Ack.Point to be equal to SackCumAck. |
1789 | */ |
1790 | if (TSN_lt(asoc->adv_peer_ack_point, ctsn)) |
1791 | asoc->adv_peer_ack_point = ctsn; |
1792 | |
1793 | /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point" |
1794 | * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as |
1795 | * the chunk next in the out-queue space is marked as "abandoned" as |
1796 | * shown in the following example: |
1797 | * |
1798 | * Assuming that a SACK arrived with the Cumulative TSN ACK 102 |
1799 | * and the Advanced.Peer.Ack.Point is updated to this value: |
1800 | * |
1801 | * out-queue at the end of ==> out-queue after Adv.Ack.Point |
1802 | * normal SACK processing local advancement |
1803 | * ... ... |
1804 | * Adv.Ack.Pt-> 102 acked 102 acked |
1805 | * 103 abandoned 103 abandoned |
1806 | * 104 abandoned Adv.Ack.P-> 104 abandoned |
1807 | * 105 105 |
1808 | * 106 acked 106 acked |
1809 | * ... ... |
1810 | * |
1811 | * In this example, the data sender successfully advanced the |
1812 | * "Advanced.Peer.Ack.Point" from 102 to 104 locally. |
1813 | */ |
1814 | list_for_each_safe(lchunk, temp, &q->abandoned) { |
1815 | chunk = list_entry(lchunk, struct sctp_chunk, |
1816 | transmitted_list); |
1817 | tsn = ntohl(chunk->subh.data_hdr->tsn); |
1818 | |
1819 | /* Remove any chunks in the abandoned queue that are acked by |
1820 | * the ctsn. |
1821 | */ |
1822 | if (TSN_lte(tsn, ctsn)) { |
1823 | list_del_init(lchunk); |
1824 | sctp_chunk_free(chunk); |
1825 | } else { |
1826 | if (TSN_lte(tsn, asoc->adv_peer_ack_point+1)) { |
1827 | asoc->adv_peer_ack_point = tsn; |
1828 | if (chunk->chunk_hdr->flags & |
1829 | SCTP_DATA_UNORDERED) |
1830 | continue; |
1831 | skip_pos = sctp_get_skip_pos(&ftsn_skip_arr[0], |
1832 | nskips, |
1833 | chunk->subh.data_hdr->stream); |
1834 | ftsn_skip_arr[skip_pos].stream = |
1835 | chunk->subh.data_hdr->stream; |
1836 | ftsn_skip_arr[skip_pos].ssn = |
1837 | chunk->subh.data_hdr->ssn; |
1838 | if (skip_pos == nskips) |
1839 | nskips++; |
1840 | if (nskips == 10) |
1841 | break; |
1842 | } else |
1843 | break; |
1844 | } |
1845 | } |
1846 | |
1847 | /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point" |
1848 | * is greater than the Cumulative TSN ACK carried in the received |
1849 | * SACK, the data sender MUST send the data receiver a FORWARD TSN |
1850 | * chunk containing the latest value of the |
1851 | * "Advanced.Peer.Ack.Point". |
1852 | * |
1853 | * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD |
1854 | * list each stream and sequence number in the forwarded TSN. This |
1855 | * information will enable the receiver to easily find any |
1856 | * stranded TSN's waiting on stream reorder queues. Each stream |
1857 | * SHOULD only be reported once; this means that if multiple |
1858 | * abandoned messages occur in the same stream then only the |
1859 | * highest abandoned stream sequence number is reported. If the |
1860 | * total size of the FORWARD TSN does NOT fit in a single MTU then |
1861 | * the sender of the FORWARD TSN SHOULD lower the |
1862 | * Advanced.Peer.Ack.Point to the last TSN that will fit in a |
1863 | * single MTU. |
1864 | */ |
1865 | if (asoc->adv_peer_ack_point > ctsn) |
1866 | ftsn_chunk = sctp_make_fwdtsn(asoc, asoc->adv_peer_ack_point, |
1867 | nskips, &ftsn_skip_arr[0]); |
1868 | |
1869 | if (ftsn_chunk) { |
1870 | list_add_tail(&ftsn_chunk->list, &q->control_chunk_list); |
1871 | SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); |
1872 | } |
1873 | } |
1874 |
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