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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, see
26 * <http://www.gnu.org/licenses/>.
27 *
28 * Please send any bug reports or fixes you make to the
29 * email address(es):
30 * lksctp developers <linux-sctp@vger.kernel.org>
31 *
32 * Written or modified by:
33 * La Monte H.P. Yarroll <piggy@acm.org>
34 * Karl Knutson <karl@athena.chicago.il.us>
35 * Perry Melange <pmelange@null.cc.uic.edu>
36 * Xingang Guo <xingang.guo@intel.com>
37 * Hui Huang <hui.huang@nokia.com>
38 * Sridhar Samudrala <sri@us.ibm.com>
39 * Jon Grimm <jgrimm@us.ibm.com>
40 */
41
42#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
43
44#include <linux/types.h>
45#include <linux/list.h> /* For struct list_head */
46#include <linux/socket.h>
47#include <linux/ip.h>
48#include <linux/slab.h>
49#include <net/sock.h> /* For skb_set_owner_w */
50
51#include <net/sctp/sctp.h>
52#include <net/sctp/sm.h>
53
54/* Declare internal functions here. */
55static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn);
56static void sctp_check_transmitted(struct sctp_outq *q,
57 struct list_head *transmitted_queue,
58 struct sctp_transport *transport,
59 union sctp_addr *saddr,
60 struct sctp_sackhdr *sack,
61 __u32 *highest_new_tsn);
62
63static void sctp_mark_missing(struct sctp_outq *q,
64 struct list_head *transmitted_queue,
65 struct sctp_transport *transport,
66 __u32 highest_new_tsn,
67 int count_of_newacks);
68
69static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 sack_ctsn);
70
71static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout);
72
73/* Add data to the front of the queue. */
74static inline void sctp_outq_head_data(struct sctp_outq *q,
75 struct sctp_chunk *ch)
76{
77 list_add(&ch->list, &q->out_chunk_list);
78 q->out_qlen += ch->skb->len;
79}
80
81/* Take data from the front of the queue. */
82static inline struct sctp_chunk *sctp_outq_dequeue_data(struct sctp_outq *q)
83{
84 struct sctp_chunk *ch = NULL;
85
86 if (!list_empty(&q->out_chunk_list)) {
87 struct list_head *entry = q->out_chunk_list.next;
88
89 ch = list_entry(entry, struct sctp_chunk, list);
90 list_del_init(entry);
91 q->out_qlen -= ch->skb->len;
92 }
93 return ch;
94}
95/* Add data chunk to the end of the queue. */
96static inline void sctp_outq_tail_data(struct sctp_outq *q,
97 struct sctp_chunk *ch)
98{
99 list_add_tail(&ch->list, &q->out_chunk_list);
100 q->out_qlen += ch->skb->len;
101}
102
103/*
104 * SFR-CACC algorithm:
105 * D) If count_of_newacks is greater than or equal to 2
106 * and t was not sent to the current primary then the
107 * sender MUST NOT increment missing report count for t.
108 */
109static inline int sctp_cacc_skip_3_1_d(struct sctp_transport *primary,
110 struct sctp_transport *transport,
111 int count_of_newacks)
112{
113 if (count_of_newacks >= 2 && transport != primary)
114 return 1;
115 return 0;
116}
117
118/*
119 * SFR-CACC algorithm:
120 * F) If count_of_newacks is less than 2, let d be the
121 * destination to which t was sent. If cacc_saw_newack
122 * is 0 for destination d, then the sender MUST NOT
123 * increment missing report count for t.
124 */
125static inline int sctp_cacc_skip_3_1_f(struct sctp_transport *transport,
126 int count_of_newacks)
127{
128 if (count_of_newacks < 2 &&
129 (transport && !transport->cacc.cacc_saw_newack))
130 return 1;
131 return 0;
132}
133
134/*
135 * SFR-CACC algorithm:
136 * 3.1) If CYCLING_CHANGEOVER is 0, the sender SHOULD
137 * execute steps C, D, F.
138 *
139 * C has been implemented in sctp_outq_sack
140 */
141static inline int sctp_cacc_skip_3_1(struct sctp_transport *primary,
142 struct sctp_transport *transport,
143 int count_of_newacks)
144{
145 if (!primary->cacc.cycling_changeover) {
146 if (sctp_cacc_skip_3_1_d(primary, transport, count_of_newacks))
147 return 1;
148 if (sctp_cacc_skip_3_1_f(transport, count_of_newacks))
149 return 1;
150 return 0;
151 }
152 return 0;
153}
154
155/*
156 * SFR-CACC algorithm:
157 * 3.2) Else if CYCLING_CHANGEOVER is 1, and t is less
158 * than next_tsn_at_change of the current primary, then
159 * the sender MUST NOT increment missing report count
160 * for t.
161 */
162static inline int sctp_cacc_skip_3_2(struct sctp_transport *primary, __u32 tsn)
163{
164 if (primary->cacc.cycling_changeover &&
165 TSN_lt(tsn, primary->cacc.next_tsn_at_change))
166 return 1;
167 return 0;
168}
169
170/*
171 * SFR-CACC algorithm:
172 * 3) If the missing report count for TSN t is to be
173 * incremented according to [RFC2960] and
174 * [SCTP_STEWART-2002], and CHANGEOVER_ACTIVE is set,
175 * then the sender MUST further execute steps 3.1 and
176 * 3.2 to determine if the missing report count for
177 * TSN t SHOULD NOT be incremented.
178 *
179 * 3.3) If 3.1 and 3.2 do not dictate that the missing
180 * report count for t should not be incremented, then
181 * the sender SHOULD increment missing report count for
182 * t (according to [RFC2960] and [SCTP_STEWART_2002]).
183 */
184static inline int sctp_cacc_skip(struct sctp_transport *primary,
185 struct sctp_transport *transport,
186 int count_of_newacks,
187 __u32 tsn)
188{
189 if (primary->cacc.changeover_active &&
190 (sctp_cacc_skip_3_1(primary, transport, count_of_newacks) ||
191 sctp_cacc_skip_3_2(primary, tsn)))
192 return 1;
193 return 0;
194}
195
196/* Initialize an existing sctp_outq. This does the boring stuff.
197 * You still need to define handlers if you really want to DO
198 * something with this structure...
199 */
200void sctp_outq_init(struct sctp_association *asoc, struct sctp_outq *q)
201{
202 memset(q, 0, sizeof(struct sctp_outq));
203
204 q->asoc = asoc;
205 INIT_LIST_HEAD(&q->out_chunk_list);
206 INIT_LIST_HEAD(&q->control_chunk_list);
207 INIT_LIST_HEAD(&q->retransmit);
208 INIT_LIST_HEAD(&q->sacked);
209 INIT_LIST_HEAD(&q->abandoned);
210}
211
212/* Free the outqueue structure and any related pending chunks.
213 */
214static void __sctp_outq_teardown(struct sctp_outq *q)
215{
216 struct sctp_transport *transport;
217 struct list_head *lchunk, *temp;
218 struct sctp_chunk *chunk, *tmp;
219
220 /* Throw away unacknowledged chunks. */
221 list_for_each_entry(transport, &q->asoc->peer.transport_addr_list,
222 transports) {
223 while ((lchunk = sctp_list_dequeue(&transport->transmitted)) != NULL) {
224 chunk = list_entry(lchunk, struct sctp_chunk,
225 transmitted_list);
226 /* Mark as part of a failed message. */
227 sctp_chunk_fail(chunk, q->error);
228 sctp_chunk_free(chunk);
229 }
230 }
231
232 /* Throw away chunks that have been gap ACKed. */
233 list_for_each_safe(lchunk, temp, &q->sacked) {
234 list_del_init(lchunk);
235 chunk = list_entry(lchunk, struct sctp_chunk,
236 transmitted_list);
237 sctp_chunk_fail(chunk, q->error);
238 sctp_chunk_free(chunk);
239 }
240
241 /* Throw away any chunks in the retransmit queue. */
242 list_for_each_safe(lchunk, temp, &q->retransmit) {
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 that are in the abandoned queue. */
251 list_for_each_safe(lchunk, temp, &q->abandoned) {
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 leftover data chunks. */
260 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) {
261
262 /* Mark as send failure. */
263 sctp_chunk_fail(chunk, q->error);
264 sctp_chunk_free(chunk);
265 }
266
267 /* Throw away any leftover control chunks. */
268 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) {
269 list_del_init(&chunk->list);
270 sctp_chunk_free(chunk);
271 }
272}
273
274void sctp_outq_teardown(struct sctp_outq *q)
275{
276 __sctp_outq_teardown(q);
277 sctp_outq_init(q->asoc, q);
278}
279
280/* Free the outqueue structure and any related pending chunks. */
281void sctp_outq_free(struct sctp_outq *q)
282{
283 /* Throw away leftover chunks. */
284 __sctp_outq_teardown(q);
285}
286
287/* Put a new chunk in an sctp_outq. */
288int sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk)
289{
290 struct net *net = sock_net(q->asoc->base.sk);
291 int error = 0;
292
293 pr_debug("%s: outq:%p, chunk:%p[%s]\n", __func__, q, chunk,
294 chunk && chunk->chunk_hdr ?
295 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) :
296 "illegal chunk");
297
298 /* If it is data, queue it up, otherwise, send it
299 * immediately.
300 */
301 if (sctp_chunk_is_data(chunk)) {
302 /* Is it OK to queue data chunks? */
303 /* From 9. Termination of Association
304 *
305 * When either endpoint performs a shutdown, the
306 * association on each peer will stop accepting new
307 * data from its user and only deliver data in queue
308 * at the time of sending or receiving the SHUTDOWN
309 * chunk.
310 */
311 switch (q->asoc->state) {
312 case SCTP_STATE_CLOSED:
313 case SCTP_STATE_SHUTDOWN_PENDING:
314 case SCTP_STATE_SHUTDOWN_SENT:
315 case SCTP_STATE_SHUTDOWN_RECEIVED:
316 case SCTP_STATE_SHUTDOWN_ACK_SENT:
317 /* Cannot send after transport endpoint shutdown */
318 error = -ESHUTDOWN;
319 break;
320
321 default:
322 pr_debug("%s: outqueueing: outq:%p, chunk:%p[%s])\n",
323 __func__, q, chunk, chunk && chunk->chunk_hdr ?
324 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) :
325 "illegal chunk");
326
327 sctp_outq_tail_data(q, chunk);
328 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED)
329 SCTP_INC_STATS(net, SCTP_MIB_OUTUNORDERCHUNKS);
330 else
331 SCTP_INC_STATS(net, SCTP_MIB_OUTORDERCHUNKS);
332 break;
333 }
334 } else {
335 list_add_tail(&chunk->list, &q->control_chunk_list);
336 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
337 }
338
339 if (error < 0)
340 return error;
341
342 if (!q->cork)
343 error = sctp_outq_flush(q, 0);
344
345 return error;
346}
347
348/* Insert a chunk into the sorted list based on the TSNs. The retransmit list
349 * and the abandoned list are in ascending order.
350 */
351static void sctp_insert_list(struct list_head *head, struct list_head *new)
352{
353 struct list_head *pos;
354 struct sctp_chunk *nchunk, *lchunk;
355 __u32 ntsn, ltsn;
356 int done = 0;
357
358 nchunk = list_entry(new, struct sctp_chunk, transmitted_list);
359 ntsn = ntohl(nchunk->subh.data_hdr->tsn);
360
361 list_for_each(pos, head) {
362 lchunk = list_entry(pos, struct sctp_chunk, transmitted_list);
363 ltsn = ntohl(lchunk->subh.data_hdr->tsn);
364 if (TSN_lt(ntsn, ltsn)) {
365 list_add(new, pos->prev);
366 done = 1;
367 break;
368 }
369 }
370 if (!done)
371 list_add_tail(new, head);
372}
373
374/* Mark all the eligible packets on a transport for retransmission. */
375void sctp_retransmit_mark(struct sctp_outq *q,
376 struct sctp_transport *transport,
377 __u8 reason)
378{
379 struct list_head *lchunk, *ltemp;
380 struct sctp_chunk *chunk;
381
382 /* Walk through the specified transmitted queue. */
383 list_for_each_safe(lchunk, ltemp, &transport->transmitted) {
384 chunk = list_entry(lchunk, struct sctp_chunk,
385 transmitted_list);
386
387 /* If the chunk is abandoned, move it to abandoned list. */
388 if (sctp_chunk_abandoned(chunk)) {
389 list_del_init(lchunk);
390 sctp_insert_list(&q->abandoned, lchunk);
391
392 /* If this chunk has not been previousely acked,
393 * stop considering it 'outstanding'. Our peer
394 * will most likely never see it since it will
395 * not be retransmitted
396 */
397 if (!chunk->tsn_gap_acked) {
398 if (chunk->transport)
399 chunk->transport->flight_size -=
400 sctp_data_size(chunk);
401 q->outstanding_bytes -= sctp_data_size(chunk);
402 q->asoc->peer.rwnd += sctp_data_size(chunk);
403 }
404 continue;
405 }
406
407 /* If we are doing retransmission due to a timeout or pmtu
408 * discovery, only the chunks that are not yet acked should
409 * be added to the retransmit queue.
410 */
411 if ((reason == SCTP_RTXR_FAST_RTX &&
412 (chunk->fast_retransmit == SCTP_NEED_FRTX)) ||
413 (reason != SCTP_RTXR_FAST_RTX && !chunk->tsn_gap_acked)) {
414 /* RFC 2960 6.2.1 Processing a Received SACK
415 *
416 * C) Any time a DATA chunk is marked for
417 * retransmission (via either T3-rtx timer expiration
418 * (Section 6.3.3) or via fast retransmit
419 * (Section 7.2.4)), add the data size of those
420 * chunks to the rwnd.
421 */
422 q->asoc->peer.rwnd += sctp_data_size(chunk);
423 q->outstanding_bytes -= sctp_data_size(chunk);
424 if (chunk->transport)
425 transport->flight_size -= sctp_data_size(chunk);
426
427 /* sctpimpguide-05 Section 2.8.2
428 * M5) If a T3-rtx timer expires, the
429 * 'TSN.Missing.Report' of all affected TSNs is set
430 * to 0.
431 */
432 chunk->tsn_missing_report = 0;
433
434 /* If a chunk that is being used for RTT measurement
435 * has to be retransmitted, we cannot use this chunk
436 * anymore for RTT measurements. Reset rto_pending so
437 * that a new RTT measurement is started when a new
438 * data chunk is sent.
439 */
440 if (chunk->rtt_in_progress) {
441 chunk->rtt_in_progress = 0;
442 transport->rto_pending = 0;
443 }
444
445 chunk->resent = 1;
446
447 /* Move the chunk to the retransmit queue. The chunks
448 * on the retransmit queue are always kept in order.
449 */
450 list_del_init(lchunk);
451 sctp_insert_list(&q->retransmit, lchunk);
452 }
453 }
454
455 pr_debug("%s: transport:%p, reason:%d, cwnd:%d, ssthresh:%d, "
456 "flight_size:%d, pba:%d\n", __func__, transport, reason,
457 transport->cwnd, transport->ssthresh, transport->flight_size,
458 transport->partial_bytes_acked);
459}
460
461/* Mark all the eligible packets on a transport for retransmission and force
462 * one packet out.
463 */
464void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
465 sctp_retransmit_reason_t reason)
466{
467 struct net *net = sock_net(q->asoc->base.sk);
468 int error = 0;
469
470 switch (reason) {
471 case SCTP_RTXR_T3_RTX:
472 SCTP_INC_STATS(net, SCTP_MIB_T3_RETRANSMITS);
473 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_T3_RTX);
474 /* Update the retran path if the T3-rtx timer has expired for
475 * the current retran path.
476 */
477 if (transport == transport->asoc->peer.retran_path)
478 sctp_assoc_update_retran_path(transport->asoc);
479 transport->asoc->rtx_data_chunks +=
480 transport->asoc->unack_data;
481 break;
482 case SCTP_RTXR_FAST_RTX:
483 SCTP_INC_STATS(net, SCTP_MIB_FAST_RETRANSMITS);
484 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_FAST_RTX);
485 q->fast_rtx = 1;
486 break;
487 case SCTP_RTXR_PMTUD:
488 SCTP_INC_STATS(net, SCTP_MIB_PMTUD_RETRANSMITS);
489 break;
490 case SCTP_RTXR_T1_RTX:
491 SCTP_INC_STATS(net, SCTP_MIB_T1_RETRANSMITS);
492 transport->asoc->init_retries++;
493 break;
494 default:
495 BUG();
496 }
497
498 sctp_retransmit_mark(q, transport, reason);
499
500 /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination,
501 * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by
502 * following the procedures outlined in C1 - C5.
503 */
504 if (reason == SCTP_RTXR_T3_RTX)
505 sctp_generate_fwdtsn(q, q->asoc->ctsn_ack_point);
506
507 /* Flush the queues only on timeout, since fast_rtx is only
508 * triggered during sack processing and the queue
509 * will be flushed at the end.
510 */
511 if (reason != SCTP_RTXR_FAST_RTX)
512 error = sctp_outq_flush(q, /* rtx_timeout */ 1);
513
514 if (error)
515 q->asoc->base.sk->sk_err = -error;
516}
517
518/*
519 * Transmit DATA chunks on the retransmit queue. Upon return from
520 * sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which
521 * need to be transmitted by the caller.
522 * We assume that pkt->transport has already been set.
523 *
524 * The return value is a normal kernel error return value.
525 */
526static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
527 int rtx_timeout, int *start_timer)
528{
529 struct list_head *lqueue;
530 struct sctp_transport *transport = pkt->transport;
531 sctp_xmit_t status;
532 struct sctp_chunk *chunk, *chunk1;
533 int fast_rtx;
534 int error = 0;
535 int timer = 0;
536 int done = 0;
537
538 lqueue = &q->retransmit;
539 fast_rtx = q->fast_rtx;
540
541 /* This loop handles time-out retransmissions, fast retransmissions,
542 * and retransmissions due to opening of whindow.
543 *
544 * RFC 2960 6.3.3 Handle T3-rtx Expiration
545 *
546 * E3) Determine how many of the earliest (i.e., lowest TSN)
547 * outstanding DATA chunks for the address for which the
548 * T3-rtx has expired will fit into a single packet, subject
549 * to the MTU constraint for the path corresponding to the
550 * destination transport address to which the retransmission
551 * is being sent (this may be different from the address for
552 * which the timer expires [see Section 6.4]). Call this value
553 * K. Bundle and retransmit those K DATA chunks in a single
554 * packet to the destination endpoint.
555 *
556 * [Just to be painfully clear, if we are retransmitting
557 * because a timeout just happened, we should send only ONE
558 * packet of retransmitted data.]
559 *
560 * For fast retransmissions we also send only ONE packet. However,
561 * if we are just flushing the queue due to open window, we'll
562 * try to send as much as possible.
563 */
564 list_for_each_entry_safe(chunk, chunk1, lqueue, transmitted_list) {
565 /* If the chunk is abandoned, move it to abandoned list. */
566 if (sctp_chunk_abandoned(chunk)) {
567 list_del_init(&chunk->transmitted_list);
568 sctp_insert_list(&q->abandoned,
569 &chunk->transmitted_list);
570 continue;
571 }
572
573 /* Make sure that Gap Acked TSNs are not retransmitted. A
574 * simple approach is just to move such TSNs out of the
575 * way and into a 'transmitted' queue and skip to the
576 * next chunk.
577 */
578 if (chunk->tsn_gap_acked) {
579 list_move_tail(&chunk->transmitted_list,
580 &transport->transmitted);
581 continue;
582 }
583
584 /* If we are doing fast retransmit, ignore non-fast_rtransmit
585 * chunks
586 */
587 if (fast_rtx && !chunk->fast_retransmit)
588 continue;
589
590redo:
591 /* Attempt to append this chunk to the packet. */
592 status = sctp_packet_append_chunk(pkt, chunk);
593
594 switch (status) {
595 case SCTP_XMIT_PMTU_FULL:
596 if (!pkt->has_data && !pkt->has_cookie_echo) {
597 /* If this packet did not contain DATA then
598 * retransmission did not happen, so do it
599 * again. We'll ignore the error here since
600 * control chunks are already freed so there
601 * is nothing we can do.
602 */
603 sctp_packet_transmit(pkt);
604 goto redo;
605 }
606
607 /* Send this packet. */
608 error = sctp_packet_transmit(pkt);
609
610 /* If we are retransmitting, we should only
611 * send a single packet.
612 * Otherwise, try appending this chunk again.
613 */
614 if (rtx_timeout || fast_rtx)
615 done = 1;
616 else
617 goto redo;
618
619 /* Bundle next chunk in the next round. */
620 break;
621
622 case SCTP_XMIT_RWND_FULL:
623 /* Send this packet. */
624 error = sctp_packet_transmit(pkt);
625
626 /* Stop sending DATA as there is no more room
627 * at the receiver.
628 */
629 done = 1;
630 break;
631
632 case SCTP_XMIT_NAGLE_DELAY:
633 /* Send this packet. */
634 error = sctp_packet_transmit(pkt);
635
636 /* Stop sending DATA because of nagle delay. */
637 done = 1;
638 break;
639
640 default:
641 /* The append was successful, so add this chunk to
642 * the transmitted list.
643 */
644 list_move_tail(&chunk->transmitted_list,
645 &transport->transmitted);
646
647 /* Mark the chunk as ineligible for fast retransmit
648 * after it is retransmitted.
649 */
650 if (chunk->fast_retransmit == SCTP_NEED_FRTX)
651 chunk->fast_retransmit = SCTP_DONT_FRTX;
652
653 q->asoc->stats.rtxchunks++;
654 break;
655 }
656
657 /* Set the timer if there were no errors */
658 if (!error && !timer)
659 timer = 1;
660
661 if (done)
662 break;
663 }
664
665 /* If we are here due to a retransmit timeout or a fast
666 * retransmit and if there are any chunks left in the retransmit
667 * queue that could not fit in the PMTU sized packet, they need
668 * to be marked as ineligible for a subsequent fast retransmit.
669 */
670 if (rtx_timeout || fast_rtx) {
671 list_for_each_entry(chunk1, lqueue, transmitted_list) {
672 if (chunk1->fast_retransmit == SCTP_NEED_FRTX)
673 chunk1->fast_retransmit = SCTP_DONT_FRTX;
674 }
675 }
676
677 *start_timer = timer;
678
679 /* Clear fast retransmit hint */
680 if (fast_rtx)
681 q->fast_rtx = 0;
682
683 return error;
684}
685
686/* Cork the outqueue so queued chunks are really queued. */
687int sctp_outq_uncork(struct sctp_outq *q)
688{
689 if (q->cork)
690 q->cork = 0;
691
692 return sctp_outq_flush(q, 0);
693}
694
695
696/*
697 * Try to flush an outqueue.
698 *
699 * Description: Send everything in q which we legally can, subject to
700 * congestion limitations.
701 * * Note: This function can be called from multiple contexts so appropriate
702 * locking concerns must be made. Today we use the sock lock to protect
703 * this function.
704 */
705static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout)
706{
707 struct sctp_packet *packet;
708 struct sctp_packet singleton;
709 struct sctp_association *asoc = q->asoc;
710 __u16 sport = asoc->base.bind_addr.port;
711 __u16 dport = asoc->peer.port;
712 __u32 vtag = asoc->peer.i.init_tag;
713 struct sctp_transport *transport = NULL;
714 struct sctp_transport *new_transport;
715 struct sctp_chunk *chunk, *tmp;
716 sctp_xmit_t status;
717 int error = 0;
718 int start_timer = 0;
719 int one_packet = 0;
720
721 /* These transports have chunks to send. */
722 struct list_head transport_list;
723 struct list_head *ltransport;
724
725 INIT_LIST_HEAD(&transport_list);
726 packet = NULL;
727
728 /*
729 * 6.10 Bundling
730 * ...
731 * When bundling control chunks with DATA chunks, an
732 * endpoint MUST place control chunks first in the outbound
733 * SCTP packet. The transmitter MUST transmit DATA chunks
734 * within a SCTP packet in increasing order of TSN.
735 * ...
736 */
737
738 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) {
739 /* RFC 5061, 5.3
740 * F1) This means that until such time as the ASCONF
741 * containing the add is acknowledged, the sender MUST
742 * NOT use the new IP address as a source for ANY SCTP
743 * packet except on carrying an ASCONF Chunk.
744 */
745 if (asoc->src_out_of_asoc_ok &&
746 chunk->chunk_hdr->type != SCTP_CID_ASCONF)
747 continue;
748
749 list_del_init(&chunk->list);
750
751 /* Pick the right transport to use. */
752 new_transport = chunk->transport;
753
754 if (!new_transport) {
755 /*
756 * If we have a prior transport pointer, see if
757 * the destination address of the chunk
758 * matches the destination address of the
759 * current transport. If not a match, then
760 * try to look up the transport with a given
761 * destination address. We do this because
762 * after processing ASCONFs, we may have new
763 * transports created.
764 */
765 if (transport &&
766 sctp_cmp_addr_exact(&chunk->dest,
767 &transport->ipaddr))
768 new_transport = transport;
769 else
770 new_transport = sctp_assoc_lookup_paddr(asoc,
771 &chunk->dest);
772
773 /* if we still don't have a new transport, then
774 * use the current active path.
775 */
776 if (!new_transport)
777 new_transport = asoc->peer.active_path;
778 } else if ((new_transport->state == SCTP_INACTIVE) ||
779 (new_transport->state == SCTP_UNCONFIRMED) ||
780 (new_transport->state == SCTP_PF)) {
781 /* If the chunk is Heartbeat or Heartbeat Ack,
782 * send it to chunk->transport, even if it's
783 * inactive.
784 *
785 * 3.3.6 Heartbeat Acknowledgement:
786 * ...
787 * A HEARTBEAT ACK is always sent to the source IP
788 * address of the IP datagram containing the
789 * HEARTBEAT chunk to which this ack is responding.
790 * ...
791 *
792 * ASCONF_ACKs also must be sent to the source.
793 */
794 if (chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT &&
795 chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT_ACK &&
796 chunk->chunk_hdr->type != SCTP_CID_ASCONF_ACK)
797 new_transport = asoc->peer.active_path;
798 }
799
800 /* Are we switching transports?
801 * Take care of transport locks.
802 */
803 if (new_transport != transport) {
804 transport = new_transport;
805 if (list_empty(&transport->send_ready)) {
806 list_add_tail(&transport->send_ready,
807 &transport_list);
808 }
809 packet = &transport->packet;
810 sctp_packet_config(packet, vtag,
811 asoc->peer.ecn_capable);
812 }
813
814 switch (chunk->chunk_hdr->type) {
815 /*
816 * 6.10 Bundling
817 * ...
818 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN
819 * COMPLETE with any other chunks. [Send them immediately.]
820 */
821 case SCTP_CID_INIT:
822 case SCTP_CID_INIT_ACK:
823 case SCTP_CID_SHUTDOWN_COMPLETE:
824 sctp_packet_init(&singleton, transport, sport, dport);
825 sctp_packet_config(&singleton, vtag, 0);
826 sctp_packet_append_chunk(&singleton, chunk);
827 error = sctp_packet_transmit(&singleton);
828 if (error < 0)
829 return error;
830 break;
831
832 case SCTP_CID_ABORT:
833 if (sctp_test_T_bit(chunk)) {
834 packet->vtag = asoc->c.my_vtag;
835 }
836 /* The following chunks are "response" chunks, i.e.
837 * they are generated in response to something we
838 * received. If we are sending these, then we can
839 * send only 1 packet containing these chunks.
840 */
841 case SCTP_CID_HEARTBEAT_ACK:
842 case SCTP_CID_SHUTDOWN_ACK:
843 case SCTP_CID_COOKIE_ACK:
844 case SCTP_CID_COOKIE_ECHO:
845 case SCTP_CID_ERROR:
846 case SCTP_CID_ECN_CWR:
847 case SCTP_CID_ASCONF_ACK:
848 one_packet = 1;
849 /* Fall through */
850
851 case SCTP_CID_SACK:
852 case SCTP_CID_HEARTBEAT:
853 case SCTP_CID_SHUTDOWN:
854 case SCTP_CID_ECN_ECNE:
855 case SCTP_CID_ASCONF:
856 case SCTP_CID_FWD_TSN:
857 status = sctp_packet_transmit_chunk(packet, chunk,
858 one_packet);
859 if (status != SCTP_XMIT_OK) {
860 /* put the chunk back */
861 list_add(&chunk->list, &q->control_chunk_list);
862 } else {
863 asoc->stats.octrlchunks++;
864 /* PR-SCTP C5) If a FORWARD TSN is sent, the
865 * sender MUST assure that at least one T3-rtx
866 * timer is running.
867 */
868 if (chunk->chunk_hdr->type == SCTP_CID_FWD_TSN)
869 sctp_transport_reset_timers(transport);
870 }
871 break;
872
873 default:
874 /* We built a chunk with an illegal type! */
875 BUG();
876 }
877 }
878
879 if (q->asoc->src_out_of_asoc_ok)
880 goto sctp_flush_out;
881
882 /* Is it OK to send data chunks? */
883 switch (asoc->state) {
884 case SCTP_STATE_COOKIE_ECHOED:
885 /* Only allow bundling when this packet has a COOKIE-ECHO
886 * chunk.
887 */
888 if (!packet || !packet->has_cookie_echo)
889 break;
890
891 /* fallthru */
892 case SCTP_STATE_ESTABLISHED:
893 case SCTP_STATE_SHUTDOWN_PENDING:
894 case SCTP_STATE_SHUTDOWN_RECEIVED:
895 /*
896 * RFC 2960 6.1 Transmission of DATA Chunks
897 *
898 * C) When the time comes for the sender to transmit,
899 * before sending new DATA chunks, the sender MUST
900 * first transmit any outstanding DATA chunks which
901 * are marked for retransmission (limited by the
902 * current cwnd).
903 */
904 if (!list_empty(&q->retransmit)) {
905 if (asoc->peer.retran_path->state == SCTP_UNCONFIRMED)
906 goto sctp_flush_out;
907 if (transport == asoc->peer.retran_path)
908 goto retran;
909
910 /* Switch transports & prepare the packet. */
911
912 transport = asoc->peer.retran_path;
913
914 if (list_empty(&transport->send_ready)) {
915 list_add_tail(&transport->send_ready,
916 &transport_list);
917 }
918
919 packet = &transport->packet;
920 sctp_packet_config(packet, vtag,
921 asoc->peer.ecn_capable);
922 retran:
923 error = sctp_outq_flush_rtx(q, packet,
924 rtx_timeout, &start_timer);
925
926 if (start_timer)
927 sctp_transport_reset_timers(transport);
928
929 /* This can happen on COOKIE-ECHO resend. Only
930 * one chunk can get bundled with a COOKIE-ECHO.
931 */
932 if (packet->has_cookie_echo)
933 goto sctp_flush_out;
934
935 /* Don't send new data if there is still data
936 * waiting to retransmit.
937 */
938 if (!list_empty(&q->retransmit))
939 goto sctp_flush_out;
940 }
941
942 /* Apply Max.Burst limitation to the current transport in
943 * case it will be used for new data. We are going to
944 * rest it before we return, but we want to apply the limit
945 * to the currently queued data.
946 */
947 if (transport)
948 sctp_transport_burst_limited(transport);
949
950 /* Finally, transmit new packets. */
951 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) {
952 /* RFC 2960 6.5 Every DATA chunk MUST carry a valid
953 * stream identifier.
954 */
955 if (chunk->sinfo.sinfo_stream >=
956 asoc->c.sinit_num_ostreams) {
957
958 /* Mark as failed send. */
959 sctp_chunk_fail(chunk, SCTP_ERROR_INV_STRM);
960 sctp_chunk_free(chunk);
961 continue;
962 }
963
964 /* Has this chunk expired? */
965 if (sctp_chunk_abandoned(chunk)) {
966 sctp_chunk_fail(chunk, 0);
967 sctp_chunk_free(chunk);
968 continue;
969 }
970
971 /* If there is a specified transport, use it.
972 * Otherwise, we want to use the active path.
973 */
974 new_transport = chunk->transport;
975 if (!new_transport ||
976 ((new_transport->state == SCTP_INACTIVE) ||
977 (new_transport->state == SCTP_UNCONFIRMED) ||
978 (new_transport->state == SCTP_PF)))
979 new_transport = asoc->peer.active_path;
980 if (new_transport->state == SCTP_UNCONFIRMED)
981 continue;
982
983 /* Change packets if necessary. */
984 if (new_transport != transport) {
985 transport = new_transport;
986
987 /* Schedule to have this transport's
988 * packet flushed.
989 */
990 if (list_empty(&transport->send_ready)) {
991 list_add_tail(&transport->send_ready,
992 &transport_list);
993 }
994
995 packet = &transport->packet;
996 sctp_packet_config(packet, vtag,
997 asoc->peer.ecn_capable);
998 /* We've switched transports, so apply the
999 * Burst limit to the new transport.
1000 */
1001 sctp_transport_burst_limited(transport);
1002 }
1003
1004 pr_debug("%s: outq:%p, chunk:%p[%s], tx-tsn:0x%x skb->head:%p "
1005 "skb->users:%d\n",
1006 __func__, q, chunk, chunk && chunk->chunk_hdr ?
1007 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) :
1008 "illegal chunk", ntohl(chunk->subh.data_hdr->tsn),
1009 chunk->skb ? chunk->skb->head : NULL, chunk->skb ?
1010 atomic_read(&chunk->skb->users) : -1);
1011
1012 /* Add the chunk to the packet. */
1013 status = sctp_packet_transmit_chunk(packet, chunk, 0);
1014
1015 switch (status) {
1016 case SCTP_XMIT_PMTU_FULL:
1017 case SCTP_XMIT_RWND_FULL:
1018 case SCTP_XMIT_NAGLE_DELAY:
1019 /* We could not append this chunk, so put
1020 * the chunk back on the output queue.
1021 */
1022 pr_debug("%s: could not transmit tsn:0x%x, status:%d\n",
1023 __func__, ntohl(chunk->subh.data_hdr->tsn),
1024 status);
1025
1026 sctp_outq_head_data(q, chunk);
1027 goto sctp_flush_out;
1028 break;
1029
1030 case SCTP_XMIT_OK:
1031 /* The sender is in the SHUTDOWN-PENDING state,
1032 * The sender MAY set the I-bit in the DATA
1033 * chunk header.
1034 */
1035 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING)
1036 chunk->chunk_hdr->flags |= SCTP_DATA_SACK_IMM;
1037 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED)
1038 asoc->stats.ouodchunks++;
1039 else
1040 asoc->stats.oodchunks++;
1041
1042 break;
1043
1044 default:
1045 BUG();
1046 }
1047
1048 /* BUG: We assume that the sctp_packet_transmit()
1049 * call below will succeed all the time and add the
1050 * chunk to the transmitted list and restart the
1051 * timers.
1052 * It is possible that the call can fail under OOM
1053 * conditions.
1054 *
1055 * Is this really a problem? Won't this behave
1056 * like a lost TSN?
1057 */
1058 list_add_tail(&chunk->transmitted_list,
1059 &transport->transmitted);
1060
1061 sctp_transport_reset_timers(transport);
1062
1063 /* Only let one DATA chunk get bundled with a
1064 * COOKIE-ECHO chunk.
1065 */
1066 if (packet->has_cookie_echo)
1067 goto sctp_flush_out;
1068 }
1069 break;
1070
1071 default:
1072 /* Do nothing. */
1073 break;
1074 }
1075
1076sctp_flush_out:
1077
1078 /* Before returning, examine all the transports touched in
1079 * this call. Right now, we bluntly force clear all the
1080 * transports. Things might change after we implement Nagle.
1081 * But such an examination is still required.
1082 *
1083 * --xguo
1084 */
1085 while ((ltransport = sctp_list_dequeue(&transport_list)) != NULL) {
1086 struct sctp_transport *t = list_entry(ltransport,
1087 struct sctp_transport,
1088 send_ready);
1089 packet = &t->packet;
1090 if (!sctp_packet_empty(packet))
1091 error = sctp_packet_transmit(packet);
1092
1093 /* Clear the burst limited state, if any */
1094 sctp_transport_burst_reset(t);
1095 }
1096
1097 return error;
1098}
1099
1100/* Update unack_data based on the incoming SACK chunk */
1101static void sctp_sack_update_unack_data(struct sctp_association *assoc,
1102 struct sctp_sackhdr *sack)
1103{
1104 sctp_sack_variable_t *frags;
1105 __u16 unack_data;
1106 int i;
1107
1108 unack_data = assoc->next_tsn - assoc->ctsn_ack_point - 1;
1109
1110 frags = sack->variable;
1111 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); i++) {
1112 unack_data -= ((ntohs(frags[i].gab.end) -
1113 ntohs(frags[i].gab.start) + 1));
1114 }
1115
1116 assoc->unack_data = unack_data;
1117}
1118
1119/* This is where we REALLY process a SACK.
1120 *
1121 * Process the SACK against the outqueue. Mostly, this just frees
1122 * things off the transmitted queue.
1123 */
1124int sctp_outq_sack(struct sctp_outq *q, struct sctp_chunk *chunk)
1125{
1126 struct sctp_association *asoc = q->asoc;
1127 struct sctp_sackhdr *sack = chunk->subh.sack_hdr;
1128 struct sctp_transport *transport;
1129 struct sctp_chunk *tchunk = NULL;
1130 struct list_head *lchunk, *transport_list, *temp;
1131 sctp_sack_variable_t *frags = sack->variable;
1132 __u32 sack_ctsn, ctsn, tsn;
1133 __u32 highest_tsn, highest_new_tsn;
1134 __u32 sack_a_rwnd;
1135 unsigned int outstanding;
1136 struct sctp_transport *primary = asoc->peer.primary_path;
1137 int count_of_newacks = 0;
1138 int gap_ack_blocks;
1139 u8 accum_moved = 0;
1140
1141 /* Grab the association's destination address list. */
1142 transport_list = &asoc->peer.transport_addr_list;
1143
1144 sack_ctsn = ntohl(sack->cum_tsn_ack);
1145 gap_ack_blocks = ntohs(sack->num_gap_ack_blocks);
1146 asoc->stats.gapcnt += gap_ack_blocks;
1147 /*
1148 * SFR-CACC algorithm:
1149 * On receipt of a SACK the sender SHOULD execute the
1150 * following statements.
1151 *
1152 * 1) If the cumulative ack in the SACK passes next tsn_at_change
1153 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be
1154 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for
1155 * all destinations.
1156 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE
1157 * is set the receiver of the SACK MUST take the following actions:
1158 *
1159 * A) Initialize the cacc_saw_newack to 0 for all destination
1160 * addresses.
1161 *
1162 * Only bother if changeover_active is set. Otherwise, this is
1163 * totally suboptimal to do on every SACK.
1164 */
1165 if (primary->cacc.changeover_active) {
1166 u8 clear_cycling = 0;
1167
1168 if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) {
1169 primary->cacc.changeover_active = 0;
1170 clear_cycling = 1;
1171 }
1172
1173 if (clear_cycling || gap_ack_blocks) {
1174 list_for_each_entry(transport, transport_list,
1175 transports) {
1176 if (clear_cycling)
1177 transport->cacc.cycling_changeover = 0;
1178 if (gap_ack_blocks)
1179 transport->cacc.cacc_saw_newack = 0;
1180 }
1181 }
1182 }
1183
1184 /* Get the highest TSN in the sack. */
1185 highest_tsn = sack_ctsn;
1186 if (gap_ack_blocks)
1187 highest_tsn += ntohs(frags[gap_ack_blocks - 1].gab.end);
1188
1189 if (TSN_lt(asoc->highest_sacked, highest_tsn))
1190 asoc->highest_sacked = highest_tsn;
1191
1192 highest_new_tsn = sack_ctsn;
1193
1194 /* Run through the retransmit queue. Credit bytes received
1195 * and free those chunks that we can.
1196 */
1197 sctp_check_transmitted(q, &q->retransmit, NULL, NULL, sack, &highest_new_tsn);
1198
1199 /* Run through the transmitted queue.
1200 * Credit bytes received and free those chunks which we can.
1201 *
1202 * This is a MASSIVE candidate for optimization.
1203 */
1204 list_for_each_entry(transport, transport_list, transports) {
1205 sctp_check_transmitted(q, &transport->transmitted,
1206 transport, &chunk->source, sack,
1207 &highest_new_tsn);
1208 /*
1209 * SFR-CACC algorithm:
1210 * C) Let count_of_newacks be the number of
1211 * destinations for which cacc_saw_newack is set.
1212 */
1213 if (transport->cacc.cacc_saw_newack)
1214 count_of_newacks++;
1215 }
1216
1217 /* Move the Cumulative TSN Ack Point if appropriate. */
1218 if (TSN_lt(asoc->ctsn_ack_point, sack_ctsn)) {
1219 asoc->ctsn_ack_point = sack_ctsn;
1220 accum_moved = 1;
1221 }
1222
1223 if (gap_ack_blocks) {
1224
1225 if (asoc->fast_recovery && accum_moved)
1226 highest_new_tsn = highest_tsn;
1227
1228 list_for_each_entry(transport, transport_list, transports)
1229 sctp_mark_missing(q, &transport->transmitted, transport,
1230 highest_new_tsn, count_of_newacks);
1231 }
1232
1233 /* Update unack_data field in the assoc. */
1234 sctp_sack_update_unack_data(asoc, sack);
1235
1236 ctsn = asoc->ctsn_ack_point;
1237
1238 /* Throw away stuff rotting on the sack queue. */
1239 list_for_each_safe(lchunk, temp, &q->sacked) {
1240 tchunk = list_entry(lchunk, struct sctp_chunk,
1241 transmitted_list);
1242 tsn = ntohl(tchunk->subh.data_hdr->tsn);
1243 if (TSN_lte(tsn, ctsn)) {
1244 list_del_init(&tchunk->transmitted_list);
1245 sctp_chunk_free(tchunk);
1246 }
1247 }
1248
1249 /* ii) Set rwnd equal to the newly received a_rwnd minus the
1250 * number of bytes still outstanding after processing the
1251 * Cumulative TSN Ack and the Gap Ack Blocks.
1252 */
1253
1254 sack_a_rwnd = ntohl(sack->a_rwnd);
1255 outstanding = q->outstanding_bytes;
1256
1257 if (outstanding < sack_a_rwnd)
1258 sack_a_rwnd -= outstanding;
1259 else
1260 sack_a_rwnd = 0;
1261
1262 asoc->peer.rwnd = sack_a_rwnd;
1263
1264 sctp_generate_fwdtsn(q, sack_ctsn);
1265
1266 pr_debug("%s: sack cumulative tsn ack:0x%x\n", __func__, sack_ctsn);
1267 pr_debug("%s: cumulative tsn ack of assoc:%p is 0x%x, "
1268 "advertised peer ack point:0x%x\n", __func__, asoc, ctsn,
1269 asoc->adv_peer_ack_point);
1270
1271 return sctp_outq_is_empty(q);
1272}
1273
1274/* Is the outqueue empty?
1275 * The queue is empty when we have not pending data, no in-flight data
1276 * and nothing pending retransmissions.
1277 */
1278int sctp_outq_is_empty(const struct sctp_outq *q)
1279{
1280 return q->out_qlen == 0 && q->outstanding_bytes == 0 &&
1281 list_empty(&q->retransmit);
1282}
1283
1284/********************************************************************
1285 * 2nd Level Abstractions
1286 ********************************************************************/
1287
1288/* Go through a transport's transmitted list or the association's retransmit
1289 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked.
1290 * The retransmit list will not have an associated transport.
1291 *
1292 * I added coherent debug information output. --xguo
1293 *
1294 * Instead of printing 'sacked' or 'kept' for each TSN on the
1295 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5.
1296 * KEPT TSN6-TSN7, etc.
1297 */
1298static void sctp_check_transmitted(struct sctp_outq *q,
1299 struct list_head *transmitted_queue,
1300 struct sctp_transport *transport,
1301 union sctp_addr *saddr,
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 bool forward_progress = false;
1315
1316 sack_ctsn = ntohl(sack->cum_tsn_ack);
1317
1318 INIT_LIST_HEAD(&tlist);
1319
1320 /* The while loop will skip empty transmitted queues. */
1321 while (NULL != (lchunk = sctp_list_dequeue(transmitted_queue))) {
1322 tchunk = list_entry(lchunk, struct sctp_chunk,
1323 transmitted_list);
1324
1325 if (sctp_chunk_abandoned(tchunk)) {
1326 /* Move the chunk to abandoned list. */
1327 sctp_insert_list(&q->abandoned, lchunk);
1328
1329 /* If this chunk has not been acked, stop
1330 * considering it as 'outstanding'.
1331 */
1332 if (!tchunk->tsn_gap_acked) {
1333 if (tchunk->transport)
1334 tchunk->transport->flight_size -=
1335 sctp_data_size(tchunk);
1336 q->outstanding_bytes -= sctp_data_size(tchunk);
1337 }
1338 continue;
1339 }
1340
1341 tsn = ntohl(tchunk->subh.data_hdr->tsn);
1342 if (sctp_acked(sack, tsn)) {
1343 /* If this queue is the retransmit queue, the
1344 * retransmit timer has already reclaimed
1345 * the outstanding bytes for this chunk, so only
1346 * count bytes associated with a transport.
1347 */
1348 if (transport) {
1349 /* If this chunk is being used for RTT
1350 * measurement, calculate the RTT and update
1351 * the RTO using this value.
1352 *
1353 * 6.3.1 C5) Karn's algorithm: RTT measurements
1354 * MUST NOT be made using packets that were
1355 * retransmitted (and thus for which it is
1356 * ambiguous whether the reply was for the
1357 * first instance of the packet or a later
1358 * instance).
1359 */
1360 if (!tchunk->tsn_gap_acked &&
1361 !tchunk->resent &&
1362 tchunk->rtt_in_progress) {
1363 tchunk->rtt_in_progress = 0;
1364 rtt = jiffies - tchunk->sent_at;
1365 sctp_transport_update_rto(transport,
1366 rtt);
1367 }
1368 }
1369
1370 /* If the chunk hasn't been marked as ACKED,
1371 * mark it and account bytes_acked if the
1372 * chunk had a valid transport (it will not
1373 * have a transport if ASCONF had deleted it
1374 * while DATA was outstanding).
1375 */
1376 if (!tchunk->tsn_gap_acked) {
1377 tchunk->tsn_gap_acked = 1;
1378 if (TSN_lt(*highest_new_tsn_in_sack, tsn))
1379 *highest_new_tsn_in_sack = tsn;
1380 bytes_acked += sctp_data_size(tchunk);
1381 if (!tchunk->transport)
1382 migrate_bytes += sctp_data_size(tchunk);
1383 forward_progress = true;
1384 }
1385
1386 if (TSN_lte(tsn, sack_ctsn)) {
1387 /* RFC 2960 6.3.2 Retransmission Timer Rules
1388 *
1389 * R3) Whenever a SACK is received
1390 * that acknowledges the DATA chunk
1391 * with the earliest outstanding TSN
1392 * for that address, restart T3-rtx
1393 * timer for that address with its
1394 * current RTO.
1395 */
1396 restart_timer = 1;
1397 forward_progress = true;
1398
1399 if (!tchunk->tsn_gap_acked) {
1400 /*
1401 * SFR-CACC algorithm:
1402 * 2) If the SACK contains gap acks
1403 * and the flag CHANGEOVER_ACTIVE is
1404 * set the receiver of the SACK MUST
1405 * take the following action:
1406 *
1407 * B) For each TSN t being acked that
1408 * has not been acked in any SACK so
1409 * far, set cacc_saw_newack to 1 for
1410 * the destination that the TSN was
1411 * sent to.
1412 */
1413 if (transport &&
1414 sack->num_gap_ack_blocks &&
1415 q->asoc->peer.primary_path->cacc.
1416 changeover_active)
1417 transport->cacc.cacc_saw_newack
1418 = 1;
1419 }
1420
1421 list_add_tail(&tchunk->transmitted_list,
1422 &q->sacked);
1423 } else {
1424 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2
1425 * M2) Each time a SACK arrives reporting
1426 * 'Stray DATA chunk(s)' record the highest TSN
1427 * reported as newly acknowledged, call this
1428 * value 'HighestTSNinSack'. A newly
1429 * acknowledged DATA chunk is one not
1430 * previously acknowledged in a SACK.
1431 *
1432 * When the SCTP sender of data receives a SACK
1433 * chunk that acknowledges, for the first time,
1434 * the receipt of a DATA chunk, all the still
1435 * unacknowledged DATA chunks whose TSN is
1436 * older than that newly acknowledged DATA
1437 * chunk, are qualified as 'Stray DATA chunks'.
1438 */
1439 list_add_tail(lchunk, &tlist);
1440 }
1441 } else {
1442 if (tchunk->tsn_gap_acked) {
1443 pr_debug("%s: receiver reneged on data TSN:0x%x\n",
1444 __func__, tsn);
1445
1446 tchunk->tsn_gap_acked = 0;
1447
1448 if (tchunk->transport)
1449 bytes_acked -= sctp_data_size(tchunk);
1450
1451 /* RFC 2960 6.3.2 Retransmission Timer Rules
1452 *
1453 * R4) Whenever a SACK is received missing a
1454 * TSN that was previously acknowledged via a
1455 * Gap Ack Block, start T3-rtx for the
1456 * destination address to which the DATA
1457 * chunk was originally
1458 * transmitted if it is not already running.
1459 */
1460 restart_timer = 1;
1461 }
1462
1463 list_add_tail(lchunk, &tlist);
1464 }
1465 }
1466
1467 if (transport) {
1468 if (bytes_acked) {
1469 struct sctp_association *asoc = transport->asoc;
1470
1471 /* We may have counted DATA that was migrated
1472 * to this transport due to DEL-IP operation.
1473 * Subtract those bytes, since the were never
1474 * send on this transport and shouldn't be
1475 * credited to this transport.
1476 */
1477 bytes_acked -= migrate_bytes;
1478
1479 /* 8.2. When an outstanding TSN is acknowledged,
1480 * the endpoint shall clear the error counter of
1481 * the destination transport address to which the
1482 * DATA chunk was last sent.
1483 * The association's overall error counter is
1484 * also cleared.
1485 */
1486 transport->error_count = 0;
1487 transport->asoc->overall_error_count = 0;
1488 forward_progress = true;
1489
1490 /*
1491 * While in SHUTDOWN PENDING, we may have started
1492 * the T5 shutdown guard timer after reaching the
1493 * retransmission limit. Stop that timer as soon
1494 * as the receiver acknowledged any data.
1495 */
1496 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING &&
1497 del_timer(&asoc->timers
1498 [SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD]))
1499 sctp_association_put(asoc);
1500
1501 /* Mark the destination transport address as
1502 * active if it is not so marked.
1503 */
1504 if ((transport->state == SCTP_INACTIVE ||
1505 transport->state == SCTP_UNCONFIRMED) &&
1506 sctp_cmp_addr_exact(&transport->ipaddr, saddr)) {
1507 sctp_assoc_control_transport(
1508 transport->asoc,
1509 transport,
1510 SCTP_TRANSPORT_UP,
1511 SCTP_RECEIVED_SACK);
1512 }
1513
1514 sctp_transport_raise_cwnd(transport, sack_ctsn,
1515 bytes_acked);
1516
1517 transport->flight_size -= bytes_acked;
1518 if (transport->flight_size == 0)
1519 transport->partial_bytes_acked = 0;
1520 q->outstanding_bytes -= bytes_acked + migrate_bytes;
1521 } else {
1522 /* RFC 2960 6.1, sctpimpguide-06 2.15.2
1523 * When a sender is doing zero window probing, it
1524 * should not timeout the association if it continues
1525 * to receive new packets from the receiver. The
1526 * reason is that the receiver MAY keep its window
1527 * closed for an indefinite time.
1528 * A sender is doing zero window probing when the
1529 * receiver's advertised window is zero, and there is
1530 * only one data chunk in flight to the receiver.
1531 *
1532 * Allow the association to timeout while in SHUTDOWN
1533 * PENDING or SHUTDOWN RECEIVED in case the receiver
1534 * stays in zero window mode forever.
1535 */
1536 if (!q->asoc->peer.rwnd &&
1537 !list_empty(&tlist) &&
1538 (sack_ctsn+2 == q->asoc->next_tsn) &&
1539 q->asoc->state < SCTP_STATE_SHUTDOWN_PENDING) {
1540 pr_debug("%s: sack received for zero window "
1541 "probe:%u\n", __func__, sack_ctsn);
1542
1543 q->asoc->overall_error_count = 0;
1544 transport->error_count = 0;
1545 }
1546 }
1547
1548 /* RFC 2960 6.3.2 Retransmission Timer Rules
1549 *
1550 * R2) Whenever all outstanding data sent to an address have
1551 * been acknowledged, turn off the T3-rtx timer of that
1552 * address.
1553 */
1554 if (!transport->flight_size) {
1555 if (del_timer(&transport->T3_rtx_timer))
1556 sctp_transport_put(transport);
1557 } else if (restart_timer) {
1558 if (!mod_timer(&transport->T3_rtx_timer,
1559 jiffies + transport->rto))
1560 sctp_transport_hold(transport);
1561 }
1562
1563 if (forward_progress) {
1564 if (transport->dst)
1565 dst_confirm(transport->dst);
1566 }
1567 }
1568
1569 list_splice(&tlist, transmitted_queue);
1570}
1571
1572/* Mark chunks as missing and consequently may get retransmitted. */
1573static void sctp_mark_missing(struct sctp_outq *q,
1574 struct list_head *transmitted_queue,
1575 struct sctp_transport *transport,
1576 __u32 highest_new_tsn_in_sack,
1577 int count_of_newacks)
1578{
1579 struct sctp_chunk *chunk;
1580 __u32 tsn;
1581 char do_fast_retransmit = 0;
1582 struct sctp_association *asoc = q->asoc;
1583 struct sctp_transport *primary = asoc->peer.primary_path;
1584
1585 list_for_each_entry(chunk, transmitted_queue, transmitted_list) {
1586
1587 tsn = ntohl(chunk->subh.data_hdr->tsn);
1588
1589 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all
1590 * 'Unacknowledged TSN's', if the TSN number of an
1591 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack'
1592 * value, increment the 'TSN.Missing.Report' count on that
1593 * chunk if it has NOT been fast retransmitted or marked for
1594 * fast retransmit already.
1595 */
1596 if (chunk->fast_retransmit == SCTP_CAN_FRTX &&
1597 !chunk->tsn_gap_acked &&
1598 TSN_lt(tsn, highest_new_tsn_in_sack)) {
1599
1600 /* SFR-CACC may require us to skip marking
1601 * this chunk as missing.
1602 */
1603 if (!transport || !sctp_cacc_skip(primary,
1604 chunk->transport,
1605 count_of_newacks, tsn)) {
1606 chunk->tsn_missing_report++;
1607
1608 pr_debug("%s: tsn:0x%x missing counter:%d\n",
1609 __func__, tsn, chunk->tsn_missing_report);
1610 }
1611 }
1612 /*
1613 * M4) If any DATA chunk is found to have a
1614 * 'TSN.Missing.Report'
1615 * value larger than or equal to 3, mark that chunk for
1616 * retransmission and start the fast retransmit procedure.
1617 */
1618
1619 if (chunk->tsn_missing_report >= 3) {
1620 chunk->fast_retransmit = SCTP_NEED_FRTX;
1621 do_fast_retransmit = 1;
1622 }
1623 }
1624
1625 if (transport) {
1626 if (do_fast_retransmit)
1627 sctp_retransmit(q, transport, SCTP_RTXR_FAST_RTX);
1628
1629 pr_debug("%s: transport:%p, cwnd:%d, ssthresh:%d, "
1630 "flight_size:%d, pba:%d\n", __func__, transport,
1631 transport->cwnd, transport->ssthresh,
1632 transport->flight_size, transport->partial_bytes_acked);
1633 }
1634}
1635
1636/* Is the given TSN acked by this packet? */
1637static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn)
1638{
1639 int i;
1640 sctp_sack_variable_t *frags;
1641 __u16 gap;
1642 __u32 ctsn = ntohl(sack->cum_tsn_ack);
1643
1644 if (TSN_lte(tsn, ctsn))
1645 goto pass;
1646
1647 /* 3.3.4 Selective Acknowledgement (SACK) (3):
1648 *
1649 * Gap Ack Blocks:
1650 * These fields contain the Gap Ack Blocks. They are repeated
1651 * for each Gap Ack Block up to the number of Gap Ack Blocks
1652 * defined in the Number of Gap Ack Blocks field. All DATA
1653 * chunks with TSNs greater than or equal to (Cumulative TSN
1654 * Ack + Gap Ack Block Start) and less than or equal to
1655 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack
1656 * Block are assumed to have been received correctly.
1657 */
1658
1659 frags = sack->variable;
1660 gap = tsn - ctsn;
1661 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); ++i) {
1662 if (TSN_lte(ntohs(frags[i].gab.start), gap) &&
1663 TSN_lte(gap, ntohs(frags[i].gab.end)))
1664 goto pass;
1665 }
1666
1667 return 0;
1668pass:
1669 return 1;
1670}
1671
1672static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip *skiplist,
1673 int nskips, __be16 stream)
1674{
1675 int i;
1676
1677 for (i = 0; i < nskips; i++) {
1678 if (skiplist[i].stream == stream)
1679 return i;
1680 }
1681 return i;
1682}
1683
1684/* Create and add a fwdtsn chunk to the outq's control queue if needed. */
1685static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 ctsn)
1686{
1687 struct sctp_association *asoc = q->asoc;
1688 struct sctp_chunk *ftsn_chunk = NULL;
1689 struct sctp_fwdtsn_skip ftsn_skip_arr[10];
1690 int nskips = 0;
1691 int skip_pos = 0;
1692 __u32 tsn;
1693 struct sctp_chunk *chunk;
1694 struct list_head *lchunk, *temp;
1695
1696 if (!asoc->peer.prsctp_capable)
1697 return;
1698
1699 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the
1700 * received SACK.
1701 *
1702 * If (Advanced.Peer.Ack.Point < SackCumAck), then update
1703 * Advanced.Peer.Ack.Point to be equal to SackCumAck.
1704 */
1705 if (TSN_lt(asoc->adv_peer_ack_point, ctsn))
1706 asoc->adv_peer_ack_point = ctsn;
1707
1708 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point"
1709 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as
1710 * the chunk next in the out-queue space is marked as "abandoned" as
1711 * shown in the following example:
1712 *
1713 * Assuming that a SACK arrived with the Cumulative TSN ACK 102
1714 * and the Advanced.Peer.Ack.Point is updated to this value:
1715 *
1716 * out-queue at the end of ==> out-queue after Adv.Ack.Point
1717 * normal SACK processing local advancement
1718 * ... ...
1719 * Adv.Ack.Pt-> 102 acked 102 acked
1720 * 103 abandoned 103 abandoned
1721 * 104 abandoned Adv.Ack.P-> 104 abandoned
1722 * 105 105
1723 * 106 acked 106 acked
1724 * ... ...
1725 *
1726 * In this example, the data sender successfully advanced the
1727 * "Advanced.Peer.Ack.Point" from 102 to 104 locally.
1728 */
1729 list_for_each_safe(lchunk, temp, &q->abandoned) {
1730 chunk = list_entry(lchunk, struct sctp_chunk,
1731 transmitted_list);
1732 tsn = ntohl(chunk->subh.data_hdr->tsn);
1733
1734 /* Remove any chunks in the abandoned queue that are acked by
1735 * the ctsn.
1736 */
1737 if (TSN_lte(tsn, ctsn)) {
1738 list_del_init(lchunk);
1739 sctp_chunk_free(chunk);
1740 } else {
1741 if (TSN_lte(tsn, asoc->adv_peer_ack_point+1)) {
1742 asoc->adv_peer_ack_point = tsn;
1743 if (chunk->chunk_hdr->flags &
1744 SCTP_DATA_UNORDERED)
1745 continue;
1746 skip_pos = sctp_get_skip_pos(&ftsn_skip_arr[0],
1747 nskips,
1748 chunk->subh.data_hdr->stream);
1749 ftsn_skip_arr[skip_pos].stream =
1750 chunk->subh.data_hdr->stream;
1751 ftsn_skip_arr[skip_pos].ssn =
1752 chunk->subh.data_hdr->ssn;
1753 if (skip_pos == nskips)
1754 nskips++;
1755 if (nskips == 10)
1756 break;
1757 } else
1758 break;
1759 }
1760 }
1761
1762 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point"
1763 * is greater than the Cumulative TSN ACK carried in the received
1764 * SACK, the data sender MUST send the data receiver a FORWARD TSN
1765 * chunk containing the latest value of the
1766 * "Advanced.Peer.Ack.Point".
1767 *
1768 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD
1769 * list each stream and sequence number in the forwarded TSN. This
1770 * information will enable the receiver to easily find any
1771 * stranded TSN's waiting on stream reorder queues. Each stream
1772 * SHOULD only be reported once; this means that if multiple
1773 * abandoned messages occur in the same stream then only the
1774 * highest abandoned stream sequence number is reported. If the
1775 * total size of the FORWARD TSN does NOT fit in a single MTU then
1776 * the sender of the FORWARD TSN SHOULD lower the
1777 * Advanced.Peer.Ack.Point to the last TSN that will fit in a
1778 * single MTU.
1779 */
1780 if (asoc->adv_peer_ack_point > ctsn)
1781 ftsn_chunk = sctp_make_fwdtsn(asoc, asoc->adv_peer_ack_point,
1782 nskips, &ftsn_skip_arr[0]);
1783
1784 if (ftsn_chunk) {
1785 list_add_tail(&ftsn_chunk->list, &q->control_chunk_list);
1786 SCTP_INC_STATS(sock_net(asoc->base.sk), SCTP_MIB_OUTCTRLCHUNKS);
1787 }
1788}
1// SPDX-License-Identifier: GPL-2.0-or-later
2/* SCTP kernel implementation
3 * (C) Copyright IBM Corp. 2001, 2004
4 * Copyright (c) 1999-2000 Cisco, Inc.
5 * Copyright (c) 1999-2001 Motorola, Inc.
6 * Copyright (c) 2001-2003 Intel Corp.
7 *
8 * This file is part of the SCTP kernel implementation
9 *
10 * These functions implement the sctp_outq class. The outqueue handles
11 * bundling and queueing of outgoing SCTP chunks.
12 *
13 * Please send any bug reports or fixes you make to the
14 * email address(es):
15 * lksctp developers <linux-sctp@vger.kernel.org>
16 *
17 * Written or modified by:
18 * La Monte H.P. Yarroll <piggy@acm.org>
19 * Karl Knutson <karl@athena.chicago.il.us>
20 * Perry Melange <pmelange@null.cc.uic.edu>
21 * Xingang Guo <xingang.guo@intel.com>
22 * Hui Huang <hui.huang@nokia.com>
23 * Sridhar Samudrala <sri@us.ibm.com>
24 * Jon Grimm <jgrimm@us.ibm.com>
25 */
26
27#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
28
29#include <linux/types.h>
30#include <linux/list.h> /* For struct list_head */
31#include <linux/socket.h>
32#include <linux/ip.h>
33#include <linux/slab.h>
34#include <net/sock.h> /* For skb_set_owner_w */
35
36#include <net/sctp/sctp.h>
37#include <net/sctp/sm.h>
38#include <net/sctp/stream_sched.h>
39#include <trace/events/sctp.h>
40
41/* Declare internal functions here. */
42static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn);
43static void sctp_check_transmitted(struct sctp_outq *q,
44 struct list_head *transmitted_queue,
45 struct sctp_transport *transport,
46 union sctp_addr *saddr,
47 struct sctp_sackhdr *sack,
48 __u32 *highest_new_tsn);
49
50static void sctp_mark_missing(struct sctp_outq *q,
51 struct list_head *transmitted_queue,
52 struct sctp_transport *transport,
53 __u32 highest_new_tsn,
54 int count_of_newacks);
55
56static void sctp_outq_flush(struct sctp_outq *q, int rtx_timeout, gfp_t gfp);
57
58/* Add data to the front of the queue. */
59static inline void sctp_outq_head_data(struct sctp_outq *q,
60 struct sctp_chunk *ch)
61{
62 struct sctp_stream_out_ext *oute;
63 __u16 stream;
64
65 list_add(&ch->list, &q->out_chunk_list);
66 q->out_qlen += ch->skb->len;
67
68 stream = sctp_chunk_stream_no(ch);
69 oute = SCTP_SO(&q->asoc->stream, stream)->ext;
70 list_add(&ch->stream_list, &oute->outq);
71}
72
73/* Take data from the front of the queue. */
74static inline struct sctp_chunk *sctp_outq_dequeue_data(struct sctp_outq *q)
75{
76 return q->sched->dequeue(q);
77}
78
79/* Add data chunk to the end of the queue. */
80static inline void sctp_outq_tail_data(struct sctp_outq *q,
81 struct sctp_chunk *ch)
82{
83 struct sctp_stream_out_ext *oute;
84 __u16 stream;
85
86 list_add_tail(&ch->list, &q->out_chunk_list);
87 q->out_qlen += ch->skb->len;
88
89 stream = sctp_chunk_stream_no(ch);
90 oute = SCTP_SO(&q->asoc->stream, stream)->ext;
91 list_add_tail(&ch->stream_list, &oute->outq);
92}
93
94/*
95 * SFR-CACC algorithm:
96 * D) If count_of_newacks is greater than or equal to 2
97 * and t was not sent to the current primary then the
98 * sender MUST NOT increment missing report count for t.
99 */
100static inline int sctp_cacc_skip_3_1_d(struct sctp_transport *primary,
101 struct sctp_transport *transport,
102 int count_of_newacks)
103{
104 if (count_of_newacks >= 2 && transport != primary)
105 return 1;
106 return 0;
107}
108
109/*
110 * SFR-CACC algorithm:
111 * F) If count_of_newacks is less than 2, let d be the
112 * destination to which t was sent. If cacc_saw_newack
113 * is 0 for destination d, then the sender MUST NOT
114 * increment missing report count for t.
115 */
116static inline int sctp_cacc_skip_3_1_f(struct sctp_transport *transport,
117 int count_of_newacks)
118{
119 if (count_of_newacks < 2 &&
120 (transport && !transport->cacc.cacc_saw_newack))
121 return 1;
122 return 0;
123}
124
125/*
126 * SFR-CACC algorithm:
127 * 3.1) If CYCLING_CHANGEOVER is 0, the sender SHOULD
128 * execute steps C, D, F.
129 *
130 * C has been implemented in sctp_outq_sack
131 */
132static inline int sctp_cacc_skip_3_1(struct sctp_transport *primary,
133 struct sctp_transport *transport,
134 int count_of_newacks)
135{
136 if (!primary->cacc.cycling_changeover) {
137 if (sctp_cacc_skip_3_1_d(primary, transport, count_of_newacks))
138 return 1;
139 if (sctp_cacc_skip_3_1_f(transport, count_of_newacks))
140 return 1;
141 return 0;
142 }
143 return 0;
144}
145
146/*
147 * SFR-CACC algorithm:
148 * 3.2) Else if CYCLING_CHANGEOVER is 1, and t is less
149 * than next_tsn_at_change of the current primary, then
150 * the sender MUST NOT increment missing report count
151 * for t.
152 */
153static inline int sctp_cacc_skip_3_2(struct sctp_transport *primary, __u32 tsn)
154{
155 if (primary->cacc.cycling_changeover &&
156 TSN_lt(tsn, primary->cacc.next_tsn_at_change))
157 return 1;
158 return 0;
159}
160
161/*
162 * SFR-CACC algorithm:
163 * 3) If the missing report count for TSN t is to be
164 * incremented according to [RFC2960] and
165 * [SCTP_STEWART-2002], and CHANGEOVER_ACTIVE is set,
166 * then the sender MUST further execute steps 3.1 and
167 * 3.2 to determine if the missing report count for
168 * TSN t SHOULD NOT be incremented.
169 *
170 * 3.3) If 3.1 and 3.2 do not dictate that the missing
171 * report count for t should not be incremented, then
172 * the sender SHOULD increment missing report count for
173 * t (according to [RFC2960] and [SCTP_STEWART_2002]).
174 */
175static inline int sctp_cacc_skip(struct sctp_transport *primary,
176 struct sctp_transport *transport,
177 int count_of_newacks,
178 __u32 tsn)
179{
180 if (primary->cacc.changeover_active &&
181 (sctp_cacc_skip_3_1(primary, transport, count_of_newacks) ||
182 sctp_cacc_skip_3_2(primary, tsn)))
183 return 1;
184 return 0;
185}
186
187/* Initialize an existing sctp_outq. This does the boring stuff.
188 * You still need to define handlers if you really want to DO
189 * something with this structure...
190 */
191void sctp_outq_init(struct sctp_association *asoc, struct sctp_outq *q)
192{
193 memset(q, 0, sizeof(struct sctp_outq));
194
195 q->asoc = asoc;
196 INIT_LIST_HEAD(&q->out_chunk_list);
197 INIT_LIST_HEAD(&q->control_chunk_list);
198 INIT_LIST_HEAD(&q->retransmit);
199 INIT_LIST_HEAD(&q->sacked);
200 INIT_LIST_HEAD(&q->abandoned);
201 sctp_sched_set_sched(asoc, sctp_sk(asoc->base.sk)->default_ss);
202}
203
204/* Free the outqueue structure and any related pending chunks.
205 */
206static void __sctp_outq_teardown(struct sctp_outq *q)
207{
208 struct sctp_transport *transport;
209 struct list_head *lchunk, *temp;
210 struct sctp_chunk *chunk, *tmp;
211
212 /* Throw away unacknowledged chunks. */
213 list_for_each_entry(transport, &q->asoc->peer.transport_addr_list,
214 transports) {
215 while ((lchunk = sctp_list_dequeue(&transport->transmitted)) != NULL) {
216 chunk = list_entry(lchunk, struct sctp_chunk,
217 transmitted_list);
218 /* Mark as part of a failed message. */
219 sctp_chunk_fail(chunk, q->error);
220 sctp_chunk_free(chunk);
221 }
222 }
223
224 /* Throw away chunks that have been gap ACKed. */
225 list_for_each_safe(lchunk, temp, &q->sacked) {
226 list_del_init(lchunk);
227 chunk = list_entry(lchunk, struct sctp_chunk,
228 transmitted_list);
229 sctp_chunk_fail(chunk, q->error);
230 sctp_chunk_free(chunk);
231 }
232
233 /* Throw away any chunks in the retransmit queue. */
234 list_for_each_safe(lchunk, temp, &q->retransmit) {
235 list_del_init(lchunk);
236 chunk = list_entry(lchunk, struct sctp_chunk,
237 transmitted_list);
238 sctp_chunk_fail(chunk, q->error);
239 sctp_chunk_free(chunk);
240 }
241
242 /* Throw away any chunks that are in the abandoned queue. */
243 list_for_each_safe(lchunk, temp, &q->abandoned) {
244 list_del_init(lchunk);
245 chunk = list_entry(lchunk, struct sctp_chunk,
246 transmitted_list);
247 sctp_chunk_fail(chunk, q->error);
248 sctp_chunk_free(chunk);
249 }
250
251 /* Throw away any leftover data chunks. */
252 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) {
253 sctp_sched_dequeue_done(q, chunk);
254
255 /* Mark as send failure. */
256 sctp_chunk_fail(chunk, q->error);
257 sctp_chunk_free(chunk);
258 }
259
260 /* Throw away any leftover control chunks. */
261 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) {
262 list_del_init(&chunk->list);
263 sctp_chunk_free(chunk);
264 }
265}
266
267void sctp_outq_teardown(struct sctp_outq *q)
268{
269 __sctp_outq_teardown(q);
270 sctp_outq_init(q->asoc, q);
271}
272
273/* Free the outqueue structure and any related pending chunks. */
274void sctp_outq_free(struct sctp_outq *q)
275{
276 /* Throw away leftover chunks. */
277 __sctp_outq_teardown(q);
278}
279
280/* Put a new chunk in an sctp_outq. */
281void sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk, gfp_t gfp)
282{
283 struct net *net = q->asoc->base.net;
284
285 pr_debug("%s: outq:%p, chunk:%p[%s]\n", __func__, q, chunk,
286 chunk && chunk->chunk_hdr ?
287 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) :
288 "illegal chunk");
289
290 /* If it is data, queue it up, otherwise, send it
291 * immediately.
292 */
293 if (sctp_chunk_is_data(chunk)) {
294 pr_debug("%s: outqueueing: outq:%p, chunk:%p[%s])\n",
295 __func__, q, chunk, chunk && chunk->chunk_hdr ?
296 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) :
297 "illegal chunk");
298
299 sctp_outq_tail_data(q, chunk);
300 if (chunk->asoc->peer.prsctp_capable &&
301 SCTP_PR_PRIO_ENABLED(chunk->sinfo.sinfo_flags))
302 chunk->asoc->sent_cnt_removable++;
303 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED)
304 SCTP_INC_STATS(net, SCTP_MIB_OUTUNORDERCHUNKS);
305 else
306 SCTP_INC_STATS(net, SCTP_MIB_OUTORDERCHUNKS);
307 } else {
308 list_add_tail(&chunk->list, &q->control_chunk_list);
309 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
310 }
311
312 if (!q->cork)
313 sctp_outq_flush(q, 0, gfp);
314}
315
316/* Insert a chunk into the sorted list based on the TSNs. The retransmit list
317 * and the abandoned list are in ascending order.
318 */
319static void sctp_insert_list(struct list_head *head, struct list_head *new)
320{
321 struct list_head *pos;
322 struct sctp_chunk *nchunk, *lchunk;
323 __u32 ntsn, ltsn;
324 int done = 0;
325
326 nchunk = list_entry(new, struct sctp_chunk, transmitted_list);
327 ntsn = ntohl(nchunk->subh.data_hdr->tsn);
328
329 list_for_each(pos, head) {
330 lchunk = list_entry(pos, struct sctp_chunk, transmitted_list);
331 ltsn = ntohl(lchunk->subh.data_hdr->tsn);
332 if (TSN_lt(ntsn, ltsn)) {
333 list_add(new, pos->prev);
334 done = 1;
335 break;
336 }
337 }
338 if (!done)
339 list_add_tail(new, head);
340}
341
342static int sctp_prsctp_prune_sent(struct sctp_association *asoc,
343 struct sctp_sndrcvinfo *sinfo,
344 struct list_head *queue, int msg_len)
345{
346 struct sctp_chunk *chk, *temp;
347
348 list_for_each_entry_safe(chk, temp, queue, transmitted_list) {
349 struct sctp_stream_out *streamout;
350
351 if (!chk->msg->abandoned &&
352 (!SCTP_PR_PRIO_ENABLED(chk->sinfo.sinfo_flags) ||
353 chk->sinfo.sinfo_timetolive <= sinfo->sinfo_timetolive))
354 continue;
355
356 chk->msg->abandoned = 1;
357 list_del_init(&chk->transmitted_list);
358 sctp_insert_list(&asoc->outqueue.abandoned,
359 &chk->transmitted_list);
360
361 streamout = SCTP_SO(&asoc->stream, chk->sinfo.sinfo_stream);
362 asoc->sent_cnt_removable--;
363 asoc->abandoned_sent[SCTP_PR_INDEX(PRIO)]++;
364 streamout->ext->abandoned_sent[SCTP_PR_INDEX(PRIO)]++;
365
366 if (queue != &asoc->outqueue.retransmit &&
367 !chk->tsn_gap_acked) {
368 if (chk->transport)
369 chk->transport->flight_size -=
370 sctp_data_size(chk);
371 asoc->outqueue.outstanding_bytes -= sctp_data_size(chk);
372 }
373
374 msg_len -= chk->skb->truesize + sizeof(struct sctp_chunk);
375 if (msg_len <= 0)
376 break;
377 }
378
379 return msg_len;
380}
381
382static int sctp_prsctp_prune_unsent(struct sctp_association *asoc,
383 struct sctp_sndrcvinfo *sinfo, int msg_len)
384{
385 struct sctp_outq *q = &asoc->outqueue;
386 struct sctp_chunk *chk, *temp;
387 struct sctp_stream_out *sout;
388
389 q->sched->unsched_all(&asoc->stream);
390
391 list_for_each_entry_safe(chk, temp, &q->out_chunk_list, list) {
392 if (!chk->msg->abandoned &&
393 (!(chk->chunk_hdr->flags & SCTP_DATA_FIRST_FRAG) ||
394 !SCTP_PR_PRIO_ENABLED(chk->sinfo.sinfo_flags) ||
395 chk->sinfo.sinfo_timetolive <= sinfo->sinfo_timetolive))
396 continue;
397
398 chk->msg->abandoned = 1;
399 sctp_sched_dequeue_common(q, chk);
400 asoc->sent_cnt_removable--;
401 asoc->abandoned_unsent[SCTP_PR_INDEX(PRIO)]++;
402
403 sout = SCTP_SO(&asoc->stream, chk->sinfo.sinfo_stream);
404 sout->ext->abandoned_unsent[SCTP_PR_INDEX(PRIO)]++;
405
406 /* clear out_curr if all frag chunks are pruned */
407 if (asoc->stream.out_curr == sout &&
408 list_is_last(&chk->frag_list, &chk->msg->chunks))
409 asoc->stream.out_curr = NULL;
410
411 msg_len -= chk->skb->truesize + sizeof(struct sctp_chunk);
412 sctp_chunk_free(chk);
413 if (msg_len <= 0)
414 break;
415 }
416
417 q->sched->sched_all(&asoc->stream);
418
419 return msg_len;
420}
421
422/* Abandon the chunks according their priorities */
423void sctp_prsctp_prune(struct sctp_association *asoc,
424 struct sctp_sndrcvinfo *sinfo, int msg_len)
425{
426 struct sctp_transport *transport;
427
428 if (!asoc->peer.prsctp_capable || !asoc->sent_cnt_removable)
429 return;
430
431 msg_len = sctp_prsctp_prune_sent(asoc, sinfo,
432 &asoc->outqueue.retransmit,
433 msg_len);
434 if (msg_len <= 0)
435 return;
436
437 list_for_each_entry(transport, &asoc->peer.transport_addr_list,
438 transports) {
439 msg_len = sctp_prsctp_prune_sent(asoc, sinfo,
440 &transport->transmitted,
441 msg_len);
442 if (msg_len <= 0)
443 return;
444 }
445
446 sctp_prsctp_prune_unsent(asoc, sinfo, msg_len);
447}
448
449/* Mark all the eligible packets on a transport for retransmission. */
450void sctp_retransmit_mark(struct sctp_outq *q,
451 struct sctp_transport *transport,
452 __u8 reason)
453{
454 struct list_head *lchunk, *ltemp;
455 struct sctp_chunk *chunk;
456
457 /* Walk through the specified transmitted queue. */
458 list_for_each_safe(lchunk, ltemp, &transport->transmitted) {
459 chunk = list_entry(lchunk, struct sctp_chunk,
460 transmitted_list);
461
462 /* If the chunk is abandoned, move it to abandoned list. */
463 if (sctp_chunk_abandoned(chunk)) {
464 list_del_init(lchunk);
465 sctp_insert_list(&q->abandoned, lchunk);
466
467 /* If this chunk has not been previousely acked,
468 * stop considering it 'outstanding'. Our peer
469 * will most likely never see it since it will
470 * not be retransmitted
471 */
472 if (!chunk->tsn_gap_acked) {
473 if (chunk->transport)
474 chunk->transport->flight_size -=
475 sctp_data_size(chunk);
476 q->outstanding_bytes -= sctp_data_size(chunk);
477 q->asoc->peer.rwnd += sctp_data_size(chunk);
478 }
479 continue;
480 }
481
482 /* If we are doing retransmission due to a timeout or pmtu
483 * discovery, only the chunks that are not yet acked should
484 * be added to the retransmit queue.
485 */
486 if ((reason == SCTP_RTXR_FAST_RTX &&
487 (chunk->fast_retransmit == SCTP_NEED_FRTX)) ||
488 (reason != SCTP_RTXR_FAST_RTX && !chunk->tsn_gap_acked)) {
489 /* RFC 2960 6.2.1 Processing a Received SACK
490 *
491 * C) Any time a DATA chunk is marked for
492 * retransmission (via either T3-rtx timer expiration
493 * (Section 6.3.3) or via fast retransmit
494 * (Section 7.2.4)), add the data size of those
495 * chunks to the rwnd.
496 */
497 q->asoc->peer.rwnd += sctp_data_size(chunk);
498 q->outstanding_bytes -= sctp_data_size(chunk);
499 if (chunk->transport)
500 transport->flight_size -= sctp_data_size(chunk);
501
502 /* sctpimpguide-05 Section 2.8.2
503 * M5) If a T3-rtx timer expires, the
504 * 'TSN.Missing.Report' of all affected TSNs is set
505 * to 0.
506 */
507 chunk->tsn_missing_report = 0;
508
509 /* If a chunk that is being used for RTT measurement
510 * has to be retransmitted, we cannot use this chunk
511 * anymore for RTT measurements. Reset rto_pending so
512 * that a new RTT measurement is started when a new
513 * data chunk is sent.
514 */
515 if (chunk->rtt_in_progress) {
516 chunk->rtt_in_progress = 0;
517 transport->rto_pending = 0;
518 }
519
520 /* Move the chunk to the retransmit queue. The chunks
521 * on the retransmit queue are always kept in order.
522 */
523 list_del_init(lchunk);
524 sctp_insert_list(&q->retransmit, lchunk);
525 }
526 }
527
528 pr_debug("%s: transport:%p, reason:%d, cwnd:%d, ssthresh:%d, "
529 "flight_size:%d, pba:%d\n", __func__, transport, reason,
530 transport->cwnd, transport->ssthresh, transport->flight_size,
531 transport->partial_bytes_acked);
532}
533
534/* Mark all the eligible packets on a transport for retransmission and force
535 * one packet out.
536 */
537void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
538 enum sctp_retransmit_reason reason)
539{
540 struct net *net = q->asoc->base.net;
541
542 switch (reason) {
543 case SCTP_RTXR_T3_RTX:
544 SCTP_INC_STATS(net, SCTP_MIB_T3_RETRANSMITS);
545 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_T3_RTX);
546 /* Update the retran path if the T3-rtx timer has expired for
547 * the current retran path.
548 */
549 if (transport == transport->asoc->peer.retran_path)
550 sctp_assoc_update_retran_path(transport->asoc);
551 transport->asoc->rtx_data_chunks +=
552 transport->asoc->unack_data;
553 if (transport->pl.state == SCTP_PL_COMPLETE &&
554 transport->asoc->unack_data)
555 sctp_transport_reset_probe_timer(transport);
556 break;
557 case SCTP_RTXR_FAST_RTX:
558 SCTP_INC_STATS(net, SCTP_MIB_FAST_RETRANSMITS);
559 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_FAST_RTX);
560 q->fast_rtx = 1;
561 break;
562 case SCTP_RTXR_PMTUD:
563 SCTP_INC_STATS(net, SCTP_MIB_PMTUD_RETRANSMITS);
564 break;
565 case SCTP_RTXR_T1_RTX:
566 SCTP_INC_STATS(net, SCTP_MIB_T1_RETRANSMITS);
567 transport->asoc->init_retries++;
568 break;
569 default:
570 BUG();
571 }
572
573 sctp_retransmit_mark(q, transport, reason);
574
575 /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination,
576 * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by
577 * following the procedures outlined in C1 - C5.
578 */
579 if (reason == SCTP_RTXR_T3_RTX)
580 q->asoc->stream.si->generate_ftsn(q, q->asoc->ctsn_ack_point);
581
582 /* Flush the queues only on timeout, since fast_rtx is only
583 * triggered during sack processing and the queue
584 * will be flushed at the end.
585 */
586 if (reason != SCTP_RTXR_FAST_RTX)
587 sctp_outq_flush(q, /* rtx_timeout */ 1, GFP_ATOMIC);
588}
589
590/*
591 * Transmit DATA chunks on the retransmit queue. Upon return from
592 * __sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which
593 * need to be transmitted by the caller.
594 * We assume that pkt->transport has already been set.
595 *
596 * The return value is a normal kernel error return value.
597 */
598static int __sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
599 int rtx_timeout, int *start_timer, gfp_t gfp)
600{
601 struct sctp_transport *transport = pkt->transport;
602 struct sctp_chunk *chunk, *chunk1;
603 struct list_head *lqueue;
604 enum sctp_xmit status;
605 int error = 0;
606 int timer = 0;
607 int done = 0;
608 int fast_rtx;
609
610 lqueue = &q->retransmit;
611 fast_rtx = q->fast_rtx;
612
613 /* This loop handles time-out retransmissions, fast retransmissions,
614 * and retransmissions due to opening of whindow.
615 *
616 * RFC 2960 6.3.3 Handle T3-rtx Expiration
617 *
618 * E3) Determine how many of the earliest (i.e., lowest TSN)
619 * outstanding DATA chunks for the address for which the
620 * T3-rtx has expired will fit into a single packet, subject
621 * to the MTU constraint for the path corresponding to the
622 * destination transport address to which the retransmission
623 * is being sent (this may be different from the address for
624 * which the timer expires [see Section 6.4]). Call this value
625 * K. Bundle and retransmit those K DATA chunks in a single
626 * packet to the destination endpoint.
627 *
628 * [Just to be painfully clear, if we are retransmitting
629 * because a timeout just happened, we should send only ONE
630 * packet of retransmitted data.]
631 *
632 * For fast retransmissions we also send only ONE packet. However,
633 * if we are just flushing the queue due to open window, we'll
634 * try to send as much as possible.
635 */
636 list_for_each_entry_safe(chunk, chunk1, lqueue, transmitted_list) {
637 /* If the chunk is abandoned, move it to abandoned list. */
638 if (sctp_chunk_abandoned(chunk)) {
639 list_del_init(&chunk->transmitted_list);
640 sctp_insert_list(&q->abandoned,
641 &chunk->transmitted_list);
642 continue;
643 }
644
645 /* Make sure that Gap Acked TSNs are not retransmitted. A
646 * simple approach is just to move such TSNs out of the
647 * way and into a 'transmitted' queue and skip to the
648 * next chunk.
649 */
650 if (chunk->tsn_gap_acked) {
651 list_move_tail(&chunk->transmitted_list,
652 &transport->transmitted);
653 continue;
654 }
655
656 /* If we are doing fast retransmit, ignore non-fast_rtransmit
657 * chunks
658 */
659 if (fast_rtx && !chunk->fast_retransmit)
660 continue;
661
662redo:
663 /* Attempt to append this chunk to the packet. */
664 status = sctp_packet_append_chunk(pkt, chunk);
665
666 switch (status) {
667 case SCTP_XMIT_PMTU_FULL:
668 if (!pkt->has_data && !pkt->has_cookie_echo) {
669 /* If this packet did not contain DATA then
670 * retransmission did not happen, so do it
671 * again. We'll ignore the error here since
672 * control chunks are already freed so there
673 * is nothing we can do.
674 */
675 sctp_packet_transmit(pkt, gfp);
676 goto redo;
677 }
678
679 /* Send this packet. */
680 error = sctp_packet_transmit(pkt, gfp);
681
682 /* If we are retransmitting, we should only
683 * send a single packet.
684 * Otherwise, try appending this chunk again.
685 */
686 if (rtx_timeout || fast_rtx)
687 done = 1;
688 else
689 goto redo;
690
691 /* Bundle next chunk in the next round. */
692 break;
693
694 case SCTP_XMIT_RWND_FULL:
695 /* Send this packet. */
696 error = sctp_packet_transmit(pkt, gfp);
697
698 /* Stop sending DATA as there is no more room
699 * at the receiver.
700 */
701 done = 1;
702 break;
703
704 case SCTP_XMIT_DELAY:
705 /* Send this packet. */
706 error = sctp_packet_transmit(pkt, gfp);
707
708 /* Stop sending DATA because of nagle delay. */
709 done = 1;
710 break;
711
712 default:
713 /* The append was successful, so add this chunk to
714 * the transmitted list.
715 */
716 list_move_tail(&chunk->transmitted_list,
717 &transport->transmitted);
718
719 /* Mark the chunk as ineligible for fast retransmit
720 * after it is retransmitted.
721 */
722 if (chunk->fast_retransmit == SCTP_NEED_FRTX)
723 chunk->fast_retransmit = SCTP_DONT_FRTX;
724
725 q->asoc->stats.rtxchunks++;
726 break;
727 }
728
729 /* Set the timer if there were no errors */
730 if (!error && !timer)
731 timer = 1;
732
733 if (done)
734 break;
735 }
736
737 /* If we are here due to a retransmit timeout or a fast
738 * retransmit and if there are any chunks left in the retransmit
739 * queue that could not fit in the PMTU sized packet, they need
740 * to be marked as ineligible for a subsequent fast retransmit.
741 */
742 if (rtx_timeout || fast_rtx) {
743 list_for_each_entry(chunk1, lqueue, transmitted_list) {
744 if (chunk1->fast_retransmit == SCTP_NEED_FRTX)
745 chunk1->fast_retransmit = SCTP_DONT_FRTX;
746 }
747 }
748
749 *start_timer = timer;
750
751 /* Clear fast retransmit hint */
752 if (fast_rtx)
753 q->fast_rtx = 0;
754
755 return error;
756}
757
758/* Cork the outqueue so queued chunks are really queued. */
759void sctp_outq_uncork(struct sctp_outq *q, gfp_t gfp)
760{
761 if (q->cork)
762 q->cork = 0;
763
764 sctp_outq_flush(q, 0, gfp);
765}
766
767static int sctp_packet_singleton(struct sctp_transport *transport,
768 struct sctp_chunk *chunk, gfp_t gfp)
769{
770 const struct sctp_association *asoc = transport->asoc;
771 const __u16 sport = asoc->base.bind_addr.port;
772 const __u16 dport = asoc->peer.port;
773 const __u32 vtag = asoc->peer.i.init_tag;
774 struct sctp_packet singleton;
775
776 sctp_packet_init(&singleton, transport, sport, dport);
777 sctp_packet_config(&singleton, vtag, 0);
778 if (sctp_packet_append_chunk(&singleton, chunk) != SCTP_XMIT_OK) {
779 list_del_init(&chunk->list);
780 sctp_chunk_free(chunk);
781 return -ENOMEM;
782 }
783 return sctp_packet_transmit(&singleton, gfp);
784}
785
786/* Struct to hold the context during sctp outq flush */
787struct sctp_flush_ctx {
788 struct sctp_outq *q;
789 /* Current transport being used. It's NOT the same as curr active one */
790 struct sctp_transport *transport;
791 /* These transports have chunks to send. */
792 struct list_head transport_list;
793 struct sctp_association *asoc;
794 /* Packet on the current transport above */
795 struct sctp_packet *packet;
796 gfp_t gfp;
797};
798
799/* transport: current transport */
800static void sctp_outq_select_transport(struct sctp_flush_ctx *ctx,
801 struct sctp_chunk *chunk)
802{
803 struct sctp_transport *new_transport = chunk->transport;
804
805 if (!new_transport) {
806 if (!sctp_chunk_is_data(chunk)) {
807 /* If we have a prior transport pointer, see if
808 * the destination address of the chunk
809 * matches the destination address of the
810 * current transport. If not a match, then
811 * try to look up the transport with a given
812 * destination address. We do this because
813 * after processing ASCONFs, we may have new
814 * transports created.
815 */
816 if (ctx->transport && sctp_cmp_addr_exact(&chunk->dest,
817 &ctx->transport->ipaddr))
818 new_transport = ctx->transport;
819 else
820 new_transport = sctp_assoc_lookup_paddr(ctx->asoc,
821 &chunk->dest);
822 }
823
824 /* if we still don't have a new transport, then
825 * use the current active path.
826 */
827 if (!new_transport)
828 new_transport = ctx->asoc->peer.active_path;
829 } else {
830 __u8 type;
831
832 switch (new_transport->state) {
833 case SCTP_INACTIVE:
834 case SCTP_UNCONFIRMED:
835 case SCTP_PF:
836 /* If the chunk is Heartbeat or Heartbeat Ack,
837 * send it to chunk->transport, even if it's
838 * inactive.
839 *
840 * 3.3.6 Heartbeat Acknowledgement:
841 * ...
842 * A HEARTBEAT ACK is always sent to the source IP
843 * address of the IP datagram containing the
844 * HEARTBEAT chunk to which this ack is responding.
845 * ...
846 *
847 * ASCONF_ACKs also must be sent to the source.
848 */
849 type = chunk->chunk_hdr->type;
850 if (type != SCTP_CID_HEARTBEAT &&
851 type != SCTP_CID_HEARTBEAT_ACK &&
852 type != SCTP_CID_ASCONF_ACK)
853 new_transport = ctx->asoc->peer.active_path;
854 break;
855 default:
856 break;
857 }
858 }
859
860 /* Are we switching transports? Take care of transport locks. */
861 if (new_transport != ctx->transport) {
862 ctx->transport = new_transport;
863 ctx->packet = &ctx->transport->packet;
864
865 if (list_empty(&ctx->transport->send_ready))
866 list_add_tail(&ctx->transport->send_ready,
867 &ctx->transport_list);
868
869 sctp_packet_config(ctx->packet,
870 ctx->asoc->peer.i.init_tag,
871 ctx->asoc->peer.ecn_capable);
872 /* We've switched transports, so apply the
873 * Burst limit to the new transport.
874 */
875 sctp_transport_burst_limited(ctx->transport);
876 }
877}
878
879static void sctp_outq_flush_ctrl(struct sctp_flush_ctx *ctx)
880{
881 struct sctp_chunk *chunk, *tmp;
882 enum sctp_xmit status;
883 int one_packet, error;
884
885 list_for_each_entry_safe(chunk, tmp, &ctx->q->control_chunk_list, list) {
886 one_packet = 0;
887
888 /* RFC 5061, 5.3
889 * F1) This means that until such time as the ASCONF
890 * containing the add is acknowledged, the sender MUST
891 * NOT use the new IP address as a source for ANY SCTP
892 * packet except on carrying an ASCONF Chunk.
893 */
894 if (ctx->asoc->src_out_of_asoc_ok &&
895 chunk->chunk_hdr->type != SCTP_CID_ASCONF)
896 continue;
897
898 list_del_init(&chunk->list);
899
900 /* Pick the right transport to use. Should always be true for
901 * the first chunk as we don't have a transport by then.
902 */
903 sctp_outq_select_transport(ctx, chunk);
904
905 switch (chunk->chunk_hdr->type) {
906 /* 6.10 Bundling
907 * ...
908 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN
909 * COMPLETE with any other chunks. [Send them immediately.]
910 */
911 case SCTP_CID_INIT:
912 case SCTP_CID_INIT_ACK:
913 case SCTP_CID_SHUTDOWN_COMPLETE:
914 error = sctp_packet_singleton(ctx->transport, chunk,
915 ctx->gfp);
916 if (error < 0) {
917 ctx->asoc->base.sk->sk_err = -error;
918 return;
919 }
920 ctx->asoc->stats.octrlchunks++;
921 break;
922
923 case SCTP_CID_ABORT:
924 if (sctp_test_T_bit(chunk))
925 ctx->packet->vtag = ctx->asoc->c.my_vtag;
926 fallthrough;
927
928 /* The following chunks are "response" chunks, i.e.
929 * they are generated in response to something we
930 * received. If we are sending these, then we can
931 * send only 1 packet containing these chunks.
932 */
933 case SCTP_CID_HEARTBEAT_ACK:
934 case SCTP_CID_SHUTDOWN_ACK:
935 case SCTP_CID_COOKIE_ACK:
936 case SCTP_CID_COOKIE_ECHO:
937 case SCTP_CID_ERROR:
938 case SCTP_CID_ECN_CWR:
939 case SCTP_CID_ASCONF_ACK:
940 one_packet = 1;
941 fallthrough;
942
943 case SCTP_CID_HEARTBEAT:
944 if (chunk->pmtu_probe) {
945 error = sctp_packet_singleton(ctx->transport,
946 chunk, ctx->gfp);
947 if (!error)
948 ctx->asoc->stats.octrlchunks++;
949 break;
950 }
951 fallthrough;
952 case SCTP_CID_SACK:
953 case SCTP_CID_SHUTDOWN:
954 case SCTP_CID_ECN_ECNE:
955 case SCTP_CID_ASCONF:
956 case SCTP_CID_FWD_TSN:
957 case SCTP_CID_I_FWD_TSN:
958 case SCTP_CID_RECONF:
959 status = sctp_packet_transmit_chunk(ctx->packet, chunk,
960 one_packet, ctx->gfp);
961 if (status != SCTP_XMIT_OK) {
962 /* put the chunk back */
963 list_add(&chunk->list, &ctx->q->control_chunk_list);
964 break;
965 }
966
967 ctx->asoc->stats.octrlchunks++;
968 /* PR-SCTP C5) If a FORWARD TSN is sent, the
969 * sender MUST assure that at least one T3-rtx
970 * timer is running.
971 */
972 if (chunk->chunk_hdr->type == SCTP_CID_FWD_TSN ||
973 chunk->chunk_hdr->type == SCTP_CID_I_FWD_TSN) {
974 sctp_transport_reset_t3_rtx(ctx->transport);
975 ctx->transport->last_time_sent = jiffies;
976 }
977
978 if (chunk == ctx->asoc->strreset_chunk)
979 sctp_transport_reset_reconf_timer(ctx->transport);
980
981 break;
982
983 default:
984 /* We built a chunk with an illegal type! */
985 BUG();
986 }
987 }
988}
989
990/* Returns false if new data shouldn't be sent */
991static bool sctp_outq_flush_rtx(struct sctp_flush_ctx *ctx,
992 int rtx_timeout)
993{
994 int error, start_timer = 0;
995
996 if (ctx->asoc->peer.retran_path->state == SCTP_UNCONFIRMED)
997 return false;
998
999 if (ctx->transport != ctx->asoc->peer.retran_path) {
1000 /* Switch transports & prepare the packet. */
1001 ctx->transport = ctx->asoc->peer.retran_path;
1002 ctx->packet = &ctx->transport->packet;
1003
1004 if (list_empty(&ctx->transport->send_ready))
1005 list_add_tail(&ctx->transport->send_ready,
1006 &ctx->transport_list);
1007
1008 sctp_packet_config(ctx->packet, ctx->asoc->peer.i.init_tag,
1009 ctx->asoc->peer.ecn_capable);
1010 }
1011
1012 error = __sctp_outq_flush_rtx(ctx->q, ctx->packet, rtx_timeout,
1013 &start_timer, ctx->gfp);
1014 if (error < 0)
1015 ctx->asoc->base.sk->sk_err = -error;
1016
1017 if (start_timer) {
1018 sctp_transport_reset_t3_rtx(ctx->transport);
1019 ctx->transport->last_time_sent = jiffies;
1020 }
1021
1022 /* This can happen on COOKIE-ECHO resend. Only
1023 * one chunk can get bundled with a COOKIE-ECHO.
1024 */
1025 if (ctx->packet->has_cookie_echo)
1026 return false;
1027
1028 /* Don't send new data if there is still data
1029 * waiting to retransmit.
1030 */
1031 if (!list_empty(&ctx->q->retransmit))
1032 return false;
1033
1034 return true;
1035}
1036
1037static void sctp_outq_flush_data(struct sctp_flush_ctx *ctx,
1038 int rtx_timeout)
1039{
1040 struct sctp_chunk *chunk;
1041 enum sctp_xmit status;
1042
1043 /* Is it OK to send data chunks? */
1044 switch (ctx->asoc->state) {
1045 case SCTP_STATE_COOKIE_ECHOED:
1046 /* Only allow bundling when this packet has a COOKIE-ECHO
1047 * chunk.
1048 */
1049 if (!ctx->packet || !ctx->packet->has_cookie_echo)
1050 return;
1051
1052 fallthrough;
1053 case SCTP_STATE_ESTABLISHED:
1054 case SCTP_STATE_SHUTDOWN_PENDING:
1055 case SCTP_STATE_SHUTDOWN_RECEIVED:
1056 break;
1057
1058 default:
1059 /* Do nothing. */
1060 return;
1061 }
1062
1063 /* RFC 2960 6.1 Transmission of DATA Chunks
1064 *
1065 * C) When the time comes for the sender to transmit,
1066 * before sending new DATA chunks, the sender MUST
1067 * first transmit any outstanding DATA chunks which
1068 * are marked for retransmission (limited by the
1069 * current cwnd).
1070 */
1071 if (!list_empty(&ctx->q->retransmit) &&
1072 !sctp_outq_flush_rtx(ctx, rtx_timeout))
1073 return;
1074
1075 /* Apply Max.Burst limitation to the current transport in
1076 * case it will be used for new data. We are going to
1077 * rest it before we return, but we want to apply the limit
1078 * to the currently queued data.
1079 */
1080 if (ctx->transport)
1081 sctp_transport_burst_limited(ctx->transport);
1082
1083 /* Finally, transmit new packets. */
1084 while ((chunk = sctp_outq_dequeue_data(ctx->q)) != NULL) {
1085 __u32 sid = ntohs(chunk->subh.data_hdr->stream);
1086 __u8 stream_state = SCTP_SO(&ctx->asoc->stream, sid)->state;
1087
1088 /* Has this chunk expired? */
1089 if (sctp_chunk_abandoned(chunk)) {
1090 sctp_sched_dequeue_done(ctx->q, chunk);
1091 sctp_chunk_fail(chunk, 0);
1092 sctp_chunk_free(chunk);
1093 continue;
1094 }
1095
1096 if (stream_state == SCTP_STREAM_CLOSED) {
1097 sctp_outq_head_data(ctx->q, chunk);
1098 break;
1099 }
1100
1101 sctp_outq_select_transport(ctx, chunk);
1102
1103 pr_debug("%s: outq:%p, chunk:%p[%s], tx-tsn:0x%x skb->head:%p skb->users:%d\n",
1104 __func__, ctx->q, chunk, chunk && chunk->chunk_hdr ?
1105 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) :
1106 "illegal chunk", ntohl(chunk->subh.data_hdr->tsn),
1107 chunk->skb ? chunk->skb->head : NULL, chunk->skb ?
1108 refcount_read(&chunk->skb->users) : -1);
1109
1110 /* Add the chunk to the packet. */
1111 status = sctp_packet_transmit_chunk(ctx->packet, chunk, 0,
1112 ctx->gfp);
1113 if (status != SCTP_XMIT_OK) {
1114 /* We could not append this chunk, so put
1115 * the chunk back on the output queue.
1116 */
1117 pr_debug("%s: could not transmit tsn:0x%x, status:%d\n",
1118 __func__, ntohl(chunk->subh.data_hdr->tsn),
1119 status);
1120
1121 sctp_outq_head_data(ctx->q, chunk);
1122 break;
1123 }
1124
1125 /* The sender is in the SHUTDOWN-PENDING state,
1126 * The sender MAY set the I-bit in the DATA
1127 * chunk header.
1128 */
1129 if (ctx->asoc->state == SCTP_STATE_SHUTDOWN_PENDING)
1130 chunk->chunk_hdr->flags |= SCTP_DATA_SACK_IMM;
1131 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED)
1132 ctx->asoc->stats.ouodchunks++;
1133 else
1134 ctx->asoc->stats.oodchunks++;
1135
1136 /* Only now it's safe to consider this
1137 * chunk as sent, sched-wise.
1138 */
1139 sctp_sched_dequeue_done(ctx->q, chunk);
1140
1141 list_add_tail(&chunk->transmitted_list,
1142 &ctx->transport->transmitted);
1143
1144 sctp_transport_reset_t3_rtx(ctx->transport);
1145 ctx->transport->last_time_sent = jiffies;
1146
1147 /* Only let one DATA chunk get bundled with a
1148 * COOKIE-ECHO chunk.
1149 */
1150 if (ctx->packet->has_cookie_echo)
1151 break;
1152 }
1153}
1154
1155static void sctp_outq_flush_transports(struct sctp_flush_ctx *ctx)
1156{
1157 struct sock *sk = ctx->asoc->base.sk;
1158 struct list_head *ltransport;
1159 struct sctp_packet *packet;
1160 struct sctp_transport *t;
1161 int error = 0;
1162
1163 while ((ltransport = sctp_list_dequeue(&ctx->transport_list)) != NULL) {
1164 t = list_entry(ltransport, struct sctp_transport, send_ready);
1165 packet = &t->packet;
1166 if (!sctp_packet_empty(packet)) {
1167 rcu_read_lock();
1168 if (t->dst && __sk_dst_get(sk) != t->dst) {
1169 dst_hold(t->dst);
1170 sk_setup_caps(sk, t->dst);
1171 }
1172 rcu_read_unlock();
1173 error = sctp_packet_transmit(packet, ctx->gfp);
1174 if (error < 0)
1175 ctx->q->asoc->base.sk->sk_err = -error;
1176 }
1177
1178 /* Clear the burst limited state, if any */
1179 sctp_transport_burst_reset(t);
1180 }
1181}
1182
1183/* Try to flush an outqueue.
1184 *
1185 * Description: Send everything in q which we legally can, subject to
1186 * congestion limitations.
1187 * * Note: This function can be called from multiple contexts so appropriate
1188 * locking concerns must be made. Today we use the sock lock to protect
1189 * this function.
1190 */
1191
1192static void sctp_outq_flush(struct sctp_outq *q, int rtx_timeout, gfp_t gfp)
1193{
1194 struct sctp_flush_ctx ctx = {
1195 .q = q,
1196 .transport = NULL,
1197 .transport_list = LIST_HEAD_INIT(ctx.transport_list),
1198 .asoc = q->asoc,
1199 .packet = NULL,
1200 .gfp = gfp,
1201 };
1202
1203 /* 6.10 Bundling
1204 * ...
1205 * When bundling control chunks with DATA chunks, an
1206 * endpoint MUST place control chunks first in the outbound
1207 * SCTP packet. The transmitter MUST transmit DATA chunks
1208 * within a SCTP packet in increasing order of TSN.
1209 * ...
1210 */
1211
1212 sctp_outq_flush_ctrl(&ctx);
1213
1214 if (q->asoc->src_out_of_asoc_ok)
1215 goto sctp_flush_out;
1216
1217 sctp_outq_flush_data(&ctx, rtx_timeout);
1218
1219sctp_flush_out:
1220
1221 sctp_outq_flush_transports(&ctx);
1222}
1223
1224/* Update unack_data based on the incoming SACK chunk */
1225static void sctp_sack_update_unack_data(struct sctp_association *assoc,
1226 struct sctp_sackhdr *sack)
1227{
1228 union sctp_sack_variable *frags;
1229 __u16 unack_data;
1230 int i;
1231
1232 unack_data = assoc->next_tsn - assoc->ctsn_ack_point - 1;
1233
1234 frags = sack->variable;
1235 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); i++) {
1236 unack_data -= ((ntohs(frags[i].gab.end) -
1237 ntohs(frags[i].gab.start) + 1));
1238 }
1239
1240 assoc->unack_data = unack_data;
1241}
1242
1243/* This is where we REALLY process a SACK.
1244 *
1245 * Process the SACK against the outqueue. Mostly, this just frees
1246 * things off the transmitted queue.
1247 */
1248int sctp_outq_sack(struct sctp_outq *q, struct sctp_chunk *chunk)
1249{
1250 struct sctp_association *asoc = q->asoc;
1251 struct sctp_sackhdr *sack = chunk->subh.sack_hdr;
1252 struct sctp_transport *transport;
1253 struct sctp_chunk *tchunk = NULL;
1254 struct list_head *lchunk, *transport_list, *temp;
1255 union sctp_sack_variable *frags = sack->variable;
1256 __u32 sack_ctsn, ctsn, tsn;
1257 __u32 highest_tsn, highest_new_tsn;
1258 __u32 sack_a_rwnd;
1259 unsigned int outstanding;
1260 struct sctp_transport *primary = asoc->peer.primary_path;
1261 int count_of_newacks = 0;
1262 int gap_ack_blocks;
1263 u8 accum_moved = 0;
1264
1265 /* Grab the association's destination address list. */
1266 transport_list = &asoc->peer.transport_addr_list;
1267
1268 /* SCTP path tracepoint for congestion control debugging. */
1269 if (trace_sctp_probe_path_enabled()) {
1270 list_for_each_entry(transport, transport_list, transports)
1271 trace_sctp_probe_path(transport, asoc);
1272 }
1273
1274 sack_ctsn = ntohl(sack->cum_tsn_ack);
1275 gap_ack_blocks = ntohs(sack->num_gap_ack_blocks);
1276 asoc->stats.gapcnt += gap_ack_blocks;
1277 /*
1278 * SFR-CACC algorithm:
1279 * On receipt of a SACK the sender SHOULD execute the
1280 * following statements.
1281 *
1282 * 1) If the cumulative ack in the SACK passes next tsn_at_change
1283 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be
1284 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for
1285 * all destinations.
1286 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE
1287 * is set the receiver of the SACK MUST take the following actions:
1288 *
1289 * A) Initialize the cacc_saw_newack to 0 for all destination
1290 * addresses.
1291 *
1292 * Only bother if changeover_active is set. Otherwise, this is
1293 * totally suboptimal to do on every SACK.
1294 */
1295 if (primary->cacc.changeover_active) {
1296 u8 clear_cycling = 0;
1297
1298 if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) {
1299 primary->cacc.changeover_active = 0;
1300 clear_cycling = 1;
1301 }
1302
1303 if (clear_cycling || gap_ack_blocks) {
1304 list_for_each_entry(transport, transport_list,
1305 transports) {
1306 if (clear_cycling)
1307 transport->cacc.cycling_changeover = 0;
1308 if (gap_ack_blocks)
1309 transport->cacc.cacc_saw_newack = 0;
1310 }
1311 }
1312 }
1313
1314 /* Get the highest TSN in the sack. */
1315 highest_tsn = sack_ctsn;
1316 if (gap_ack_blocks)
1317 highest_tsn += ntohs(frags[gap_ack_blocks - 1].gab.end);
1318
1319 if (TSN_lt(asoc->highest_sacked, highest_tsn))
1320 asoc->highest_sacked = highest_tsn;
1321
1322 highest_new_tsn = sack_ctsn;
1323
1324 /* Run through the retransmit queue. Credit bytes received
1325 * and free those chunks that we can.
1326 */
1327 sctp_check_transmitted(q, &q->retransmit, NULL, NULL, sack, &highest_new_tsn);
1328
1329 /* Run through the transmitted queue.
1330 * Credit bytes received and free those chunks which we can.
1331 *
1332 * This is a MASSIVE candidate for optimization.
1333 */
1334 list_for_each_entry(transport, transport_list, transports) {
1335 sctp_check_transmitted(q, &transport->transmitted,
1336 transport, &chunk->source, sack,
1337 &highest_new_tsn);
1338 /*
1339 * SFR-CACC algorithm:
1340 * C) Let count_of_newacks be the number of
1341 * destinations for which cacc_saw_newack is set.
1342 */
1343 if (transport->cacc.cacc_saw_newack)
1344 count_of_newacks++;
1345 }
1346
1347 /* Move the Cumulative TSN Ack Point if appropriate. */
1348 if (TSN_lt(asoc->ctsn_ack_point, sack_ctsn)) {
1349 asoc->ctsn_ack_point = sack_ctsn;
1350 accum_moved = 1;
1351 }
1352
1353 if (gap_ack_blocks) {
1354
1355 if (asoc->fast_recovery && accum_moved)
1356 highest_new_tsn = highest_tsn;
1357
1358 list_for_each_entry(transport, transport_list, transports)
1359 sctp_mark_missing(q, &transport->transmitted, transport,
1360 highest_new_tsn, count_of_newacks);
1361 }
1362
1363 /* Update unack_data field in the assoc. */
1364 sctp_sack_update_unack_data(asoc, sack);
1365
1366 ctsn = asoc->ctsn_ack_point;
1367
1368 /* Throw away stuff rotting on the sack queue. */
1369 list_for_each_safe(lchunk, temp, &q->sacked) {
1370 tchunk = list_entry(lchunk, struct sctp_chunk,
1371 transmitted_list);
1372 tsn = ntohl(tchunk->subh.data_hdr->tsn);
1373 if (TSN_lte(tsn, ctsn)) {
1374 list_del_init(&tchunk->transmitted_list);
1375 if (asoc->peer.prsctp_capable &&
1376 SCTP_PR_PRIO_ENABLED(chunk->sinfo.sinfo_flags))
1377 asoc->sent_cnt_removable--;
1378 sctp_chunk_free(tchunk);
1379 }
1380 }
1381
1382 /* ii) Set rwnd equal to the newly received a_rwnd minus the
1383 * number of bytes still outstanding after processing the
1384 * Cumulative TSN Ack and the Gap Ack Blocks.
1385 */
1386
1387 sack_a_rwnd = ntohl(sack->a_rwnd);
1388 asoc->peer.zero_window_announced = !sack_a_rwnd;
1389 outstanding = q->outstanding_bytes;
1390
1391 if (outstanding < sack_a_rwnd)
1392 sack_a_rwnd -= outstanding;
1393 else
1394 sack_a_rwnd = 0;
1395
1396 asoc->peer.rwnd = sack_a_rwnd;
1397
1398 asoc->stream.si->generate_ftsn(q, sack_ctsn);
1399
1400 pr_debug("%s: sack cumulative tsn ack:0x%x\n", __func__, sack_ctsn);
1401 pr_debug("%s: cumulative tsn ack of assoc:%p is 0x%x, "
1402 "advertised peer ack point:0x%x\n", __func__, asoc, ctsn,
1403 asoc->adv_peer_ack_point);
1404
1405 return sctp_outq_is_empty(q);
1406}
1407
1408/* Is the outqueue empty?
1409 * The queue is empty when we have not pending data, no in-flight data
1410 * and nothing pending retransmissions.
1411 */
1412int sctp_outq_is_empty(const struct sctp_outq *q)
1413{
1414 return q->out_qlen == 0 && q->outstanding_bytes == 0 &&
1415 list_empty(&q->retransmit);
1416}
1417
1418/********************************************************************
1419 * 2nd Level Abstractions
1420 ********************************************************************/
1421
1422/* Go through a transport's transmitted list or the association's retransmit
1423 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked.
1424 * The retransmit list will not have an associated transport.
1425 *
1426 * I added coherent debug information output. --xguo
1427 *
1428 * Instead of printing 'sacked' or 'kept' for each TSN on the
1429 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5.
1430 * KEPT TSN6-TSN7, etc.
1431 */
1432static void sctp_check_transmitted(struct sctp_outq *q,
1433 struct list_head *transmitted_queue,
1434 struct sctp_transport *transport,
1435 union sctp_addr *saddr,
1436 struct sctp_sackhdr *sack,
1437 __u32 *highest_new_tsn_in_sack)
1438{
1439 struct list_head *lchunk;
1440 struct sctp_chunk *tchunk;
1441 struct list_head tlist;
1442 __u32 tsn;
1443 __u32 sack_ctsn;
1444 __u32 rtt;
1445 __u8 restart_timer = 0;
1446 int bytes_acked = 0;
1447 int migrate_bytes = 0;
1448 bool forward_progress = false;
1449
1450 sack_ctsn = ntohl(sack->cum_tsn_ack);
1451
1452 INIT_LIST_HEAD(&tlist);
1453
1454 /* The while loop will skip empty transmitted queues. */
1455 while (NULL != (lchunk = sctp_list_dequeue(transmitted_queue))) {
1456 tchunk = list_entry(lchunk, struct sctp_chunk,
1457 transmitted_list);
1458
1459 if (sctp_chunk_abandoned(tchunk)) {
1460 /* Move the chunk to abandoned list. */
1461 sctp_insert_list(&q->abandoned, lchunk);
1462
1463 /* If this chunk has not been acked, stop
1464 * considering it as 'outstanding'.
1465 */
1466 if (transmitted_queue != &q->retransmit &&
1467 !tchunk->tsn_gap_acked) {
1468 if (tchunk->transport)
1469 tchunk->transport->flight_size -=
1470 sctp_data_size(tchunk);
1471 q->outstanding_bytes -= sctp_data_size(tchunk);
1472 }
1473 continue;
1474 }
1475
1476 tsn = ntohl(tchunk->subh.data_hdr->tsn);
1477 if (sctp_acked(sack, tsn)) {
1478 /* If this queue is the retransmit queue, the
1479 * retransmit timer has already reclaimed
1480 * the outstanding bytes for this chunk, so only
1481 * count bytes associated with a transport.
1482 */
1483 if (transport && !tchunk->tsn_gap_acked) {
1484 /* If this chunk is being used for RTT
1485 * measurement, calculate the RTT and update
1486 * the RTO using this value.
1487 *
1488 * 6.3.1 C5) Karn's algorithm: RTT measurements
1489 * MUST NOT be made using packets that were
1490 * retransmitted (and thus for which it is
1491 * ambiguous whether the reply was for the
1492 * first instance of the packet or a later
1493 * instance).
1494 */
1495 if (!sctp_chunk_retransmitted(tchunk) &&
1496 tchunk->rtt_in_progress) {
1497 tchunk->rtt_in_progress = 0;
1498 rtt = jiffies - tchunk->sent_at;
1499 sctp_transport_update_rto(transport,
1500 rtt);
1501 }
1502
1503 if (TSN_lte(tsn, sack_ctsn)) {
1504 /*
1505 * SFR-CACC algorithm:
1506 * 2) If the SACK contains gap acks
1507 * and the flag CHANGEOVER_ACTIVE is
1508 * set the receiver of the SACK MUST
1509 * take the following action:
1510 *
1511 * B) For each TSN t being acked that
1512 * has not been acked in any SACK so
1513 * far, set cacc_saw_newack to 1 for
1514 * the destination that the TSN was
1515 * sent to.
1516 */
1517 if (sack->num_gap_ack_blocks &&
1518 q->asoc->peer.primary_path->cacc.
1519 changeover_active)
1520 transport->cacc.cacc_saw_newack
1521 = 1;
1522 }
1523 }
1524
1525 /* If the chunk hasn't been marked as ACKED,
1526 * mark it and account bytes_acked if the
1527 * chunk had a valid transport (it will not
1528 * have a transport if ASCONF had deleted it
1529 * while DATA was outstanding).
1530 */
1531 if (!tchunk->tsn_gap_acked) {
1532 tchunk->tsn_gap_acked = 1;
1533 if (TSN_lt(*highest_new_tsn_in_sack, tsn))
1534 *highest_new_tsn_in_sack = tsn;
1535 bytes_acked += sctp_data_size(tchunk);
1536 if (!tchunk->transport)
1537 migrate_bytes += sctp_data_size(tchunk);
1538 forward_progress = true;
1539 }
1540
1541 if (TSN_lte(tsn, sack_ctsn)) {
1542 /* RFC 2960 6.3.2 Retransmission Timer Rules
1543 *
1544 * R3) Whenever a SACK is received
1545 * that acknowledges the DATA chunk
1546 * with the earliest outstanding TSN
1547 * for that address, restart T3-rtx
1548 * timer for that address with its
1549 * current RTO.
1550 */
1551 restart_timer = 1;
1552 forward_progress = true;
1553
1554 list_add_tail(&tchunk->transmitted_list,
1555 &q->sacked);
1556 } else {
1557 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2
1558 * M2) Each time a SACK arrives reporting
1559 * 'Stray DATA chunk(s)' record the highest TSN
1560 * reported as newly acknowledged, call this
1561 * value 'HighestTSNinSack'. A newly
1562 * acknowledged DATA chunk is one not
1563 * previously acknowledged in a SACK.
1564 *
1565 * When the SCTP sender of data receives a SACK
1566 * chunk that acknowledges, for the first time,
1567 * the receipt of a DATA chunk, all the still
1568 * unacknowledged DATA chunks whose TSN is
1569 * older than that newly acknowledged DATA
1570 * chunk, are qualified as 'Stray DATA chunks'.
1571 */
1572 list_add_tail(lchunk, &tlist);
1573 }
1574 } else {
1575 if (tchunk->tsn_gap_acked) {
1576 pr_debug("%s: receiver reneged on data TSN:0x%x\n",
1577 __func__, tsn);
1578
1579 tchunk->tsn_gap_acked = 0;
1580
1581 if (tchunk->transport)
1582 bytes_acked -= sctp_data_size(tchunk);
1583
1584 /* RFC 2960 6.3.2 Retransmission Timer Rules
1585 *
1586 * R4) Whenever a SACK is received missing a
1587 * TSN that was previously acknowledged via a
1588 * Gap Ack Block, start T3-rtx for the
1589 * destination address to which the DATA
1590 * chunk was originally
1591 * transmitted if it is not already running.
1592 */
1593 restart_timer = 1;
1594 }
1595
1596 list_add_tail(lchunk, &tlist);
1597 }
1598 }
1599
1600 if (transport) {
1601 if (bytes_acked) {
1602 struct sctp_association *asoc = transport->asoc;
1603
1604 /* We may have counted DATA that was migrated
1605 * to this transport due to DEL-IP operation.
1606 * Subtract those bytes, since the were never
1607 * send on this transport and shouldn't be
1608 * credited to this transport.
1609 */
1610 bytes_acked -= migrate_bytes;
1611
1612 /* 8.2. When an outstanding TSN is acknowledged,
1613 * the endpoint shall clear the error counter of
1614 * the destination transport address to which the
1615 * DATA chunk was last sent.
1616 * The association's overall error counter is
1617 * also cleared.
1618 */
1619 transport->error_count = 0;
1620 transport->asoc->overall_error_count = 0;
1621 forward_progress = true;
1622
1623 /*
1624 * While in SHUTDOWN PENDING, we may have started
1625 * the T5 shutdown guard timer after reaching the
1626 * retransmission limit. Stop that timer as soon
1627 * as the receiver acknowledged any data.
1628 */
1629 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING &&
1630 del_timer(&asoc->timers
1631 [SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD]))
1632 sctp_association_put(asoc);
1633
1634 /* Mark the destination transport address as
1635 * active if it is not so marked.
1636 */
1637 if ((transport->state == SCTP_INACTIVE ||
1638 transport->state == SCTP_UNCONFIRMED) &&
1639 sctp_cmp_addr_exact(&transport->ipaddr, saddr)) {
1640 sctp_assoc_control_transport(
1641 transport->asoc,
1642 transport,
1643 SCTP_TRANSPORT_UP,
1644 SCTP_RECEIVED_SACK);
1645 }
1646
1647 sctp_transport_raise_cwnd(transport, sack_ctsn,
1648 bytes_acked);
1649
1650 transport->flight_size -= bytes_acked;
1651 if (transport->flight_size == 0)
1652 transport->partial_bytes_acked = 0;
1653 q->outstanding_bytes -= bytes_acked + migrate_bytes;
1654 } else {
1655 /* RFC 2960 6.1, sctpimpguide-06 2.15.2
1656 * When a sender is doing zero window probing, it
1657 * should not timeout the association if it continues
1658 * to receive new packets from the receiver. The
1659 * reason is that the receiver MAY keep its window
1660 * closed for an indefinite time.
1661 * A sender is doing zero window probing when the
1662 * receiver's advertised window is zero, and there is
1663 * only one data chunk in flight to the receiver.
1664 *
1665 * Allow the association to timeout while in SHUTDOWN
1666 * PENDING or SHUTDOWN RECEIVED in case the receiver
1667 * stays in zero window mode forever.
1668 */
1669 if (!q->asoc->peer.rwnd &&
1670 !list_empty(&tlist) &&
1671 (sack_ctsn+2 == q->asoc->next_tsn) &&
1672 q->asoc->state < SCTP_STATE_SHUTDOWN_PENDING) {
1673 pr_debug("%s: sack received for zero window "
1674 "probe:%u\n", __func__, sack_ctsn);
1675
1676 q->asoc->overall_error_count = 0;
1677 transport->error_count = 0;
1678 }
1679 }
1680
1681 /* RFC 2960 6.3.2 Retransmission Timer Rules
1682 *
1683 * R2) Whenever all outstanding data sent to an address have
1684 * been acknowledged, turn off the T3-rtx timer of that
1685 * address.
1686 */
1687 if (!transport->flight_size) {
1688 if (del_timer(&transport->T3_rtx_timer))
1689 sctp_transport_put(transport);
1690 } else if (restart_timer) {
1691 if (!mod_timer(&transport->T3_rtx_timer,
1692 jiffies + transport->rto))
1693 sctp_transport_hold(transport);
1694 }
1695
1696 if (forward_progress) {
1697 if (transport->dst)
1698 sctp_transport_dst_confirm(transport);
1699 }
1700 }
1701
1702 list_splice(&tlist, transmitted_queue);
1703}
1704
1705/* Mark chunks as missing and consequently may get retransmitted. */
1706static void sctp_mark_missing(struct sctp_outq *q,
1707 struct list_head *transmitted_queue,
1708 struct sctp_transport *transport,
1709 __u32 highest_new_tsn_in_sack,
1710 int count_of_newacks)
1711{
1712 struct sctp_chunk *chunk;
1713 __u32 tsn;
1714 char do_fast_retransmit = 0;
1715 struct sctp_association *asoc = q->asoc;
1716 struct sctp_transport *primary = asoc->peer.primary_path;
1717
1718 list_for_each_entry(chunk, transmitted_queue, transmitted_list) {
1719
1720 tsn = ntohl(chunk->subh.data_hdr->tsn);
1721
1722 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all
1723 * 'Unacknowledged TSN's', if the TSN number of an
1724 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack'
1725 * value, increment the 'TSN.Missing.Report' count on that
1726 * chunk if it has NOT been fast retransmitted or marked for
1727 * fast retransmit already.
1728 */
1729 if (chunk->fast_retransmit == SCTP_CAN_FRTX &&
1730 !chunk->tsn_gap_acked &&
1731 TSN_lt(tsn, highest_new_tsn_in_sack)) {
1732
1733 /* SFR-CACC may require us to skip marking
1734 * this chunk as missing.
1735 */
1736 if (!transport || !sctp_cacc_skip(primary,
1737 chunk->transport,
1738 count_of_newacks, tsn)) {
1739 chunk->tsn_missing_report++;
1740
1741 pr_debug("%s: tsn:0x%x missing counter:%d\n",
1742 __func__, tsn, chunk->tsn_missing_report);
1743 }
1744 }
1745 /*
1746 * M4) If any DATA chunk is found to have a
1747 * 'TSN.Missing.Report'
1748 * value larger than or equal to 3, mark that chunk for
1749 * retransmission and start the fast retransmit procedure.
1750 */
1751
1752 if (chunk->tsn_missing_report >= 3) {
1753 chunk->fast_retransmit = SCTP_NEED_FRTX;
1754 do_fast_retransmit = 1;
1755 }
1756 }
1757
1758 if (transport) {
1759 if (do_fast_retransmit)
1760 sctp_retransmit(q, transport, SCTP_RTXR_FAST_RTX);
1761
1762 pr_debug("%s: transport:%p, cwnd:%d, ssthresh:%d, "
1763 "flight_size:%d, pba:%d\n", __func__, transport,
1764 transport->cwnd, transport->ssthresh,
1765 transport->flight_size, transport->partial_bytes_acked);
1766 }
1767}
1768
1769/* Is the given TSN acked by this packet? */
1770static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn)
1771{
1772 __u32 ctsn = ntohl(sack->cum_tsn_ack);
1773 union sctp_sack_variable *frags;
1774 __u16 tsn_offset, blocks;
1775 int i;
1776
1777 if (TSN_lte(tsn, ctsn))
1778 goto pass;
1779
1780 /* 3.3.4 Selective Acknowledgment (SACK) (3):
1781 *
1782 * Gap Ack Blocks:
1783 * These fields contain the Gap Ack Blocks. They are repeated
1784 * for each Gap Ack Block up to the number of Gap Ack Blocks
1785 * defined in the Number of Gap Ack Blocks field. All DATA
1786 * chunks with TSNs greater than or equal to (Cumulative TSN
1787 * Ack + Gap Ack Block Start) and less than or equal to
1788 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack
1789 * Block are assumed to have been received correctly.
1790 */
1791
1792 frags = sack->variable;
1793 blocks = ntohs(sack->num_gap_ack_blocks);
1794 tsn_offset = tsn - ctsn;
1795 for (i = 0; i < blocks; ++i) {
1796 if (tsn_offset >= ntohs(frags[i].gab.start) &&
1797 tsn_offset <= ntohs(frags[i].gab.end))
1798 goto pass;
1799 }
1800
1801 return 0;
1802pass:
1803 return 1;
1804}
1805
1806static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip *skiplist,
1807 int nskips, __be16 stream)
1808{
1809 int i;
1810
1811 for (i = 0; i < nskips; i++) {
1812 if (skiplist[i].stream == stream)
1813 return i;
1814 }
1815 return i;
1816}
1817
1818/* Create and add a fwdtsn chunk to the outq's control queue if needed. */
1819void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 ctsn)
1820{
1821 struct sctp_association *asoc = q->asoc;
1822 struct sctp_chunk *ftsn_chunk = NULL;
1823 struct sctp_fwdtsn_skip ftsn_skip_arr[10];
1824 int nskips = 0;
1825 int skip_pos = 0;
1826 __u32 tsn;
1827 struct sctp_chunk *chunk;
1828 struct list_head *lchunk, *temp;
1829
1830 if (!asoc->peer.prsctp_capable)
1831 return;
1832
1833 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the
1834 * received SACK.
1835 *
1836 * If (Advanced.Peer.Ack.Point < SackCumAck), then update
1837 * Advanced.Peer.Ack.Point to be equal to SackCumAck.
1838 */
1839 if (TSN_lt(asoc->adv_peer_ack_point, ctsn))
1840 asoc->adv_peer_ack_point = ctsn;
1841
1842 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point"
1843 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as
1844 * the chunk next in the out-queue space is marked as "abandoned" as
1845 * shown in the following example:
1846 *
1847 * Assuming that a SACK arrived with the Cumulative TSN ACK 102
1848 * and the Advanced.Peer.Ack.Point is updated to this value:
1849 *
1850 * out-queue at the end of ==> out-queue after Adv.Ack.Point
1851 * normal SACK processing local advancement
1852 * ... ...
1853 * Adv.Ack.Pt-> 102 acked 102 acked
1854 * 103 abandoned 103 abandoned
1855 * 104 abandoned Adv.Ack.P-> 104 abandoned
1856 * 105 105
1857 * 106 acked 106 acked
1858 * ... ...
1859 *
1860 * In this example, the data sender successfully advanced the
1861 * "Advanced.Peer.Ack.Point" from 102 to 104 locally.
1862 */
1863 list_for_each_safe(lchunk, temp, &q->abandoned) {
1864 chunk = list_entry(lchunk, struct sctp_chunk,
1865 transmitted_list);
1866 tsn = ntohl(chunk->subh.data_hdr->tsn);
1867
1868 /* Remove any chunks in the abandoned queue that are acked by
1869 * the ctsn.
1870 */
1871 if (TSN_lte(tsn, ctsn)) {
1872 list_del_init(lchunk);
1873 sctp_chunk_free(chunk);
1874 } else {
1875 if (TSN_lte(tsn, asoc->adv_peer_ack_point+1)) {
1876 asoc->adv_peer_ack_point = tsn;
1877 if (chunk->chunk_hdr->flags &
1878 SCTP_DATA_UNORDERED)
1879 continue;
1880 skip_pos = sctp_get_skip_pos(&ftsn_skip_arr[0],
1881 nskips,
1882 chunk->subh.data_hdr->stream);
1883 ftsn_skip_arr[skip_pos].stream =
1884 chunk->subh.data_hdr->stream;
1885 ftsn_skip_arr[skip_pos].ssn =
1886 chunk->subh.data_hdr->ssn;
1887 if (skip_pos == nskips)
1888 nskips++;
1889 if (nskips == 10)
1890 break;
1891 } else
1892 break;
1893 }
1894 }
1895
1896 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point"
1897 * is greater than the Cumulative TSN ACK carried in the received
1898 * SACK, the data sender MUST send the data receiver a FORWARD TSN
1899 * chunk containing the latest value of the
1900 * "Advanced.Peer.Ack.Point".
1901 *
1902 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD
1903 * list each stream and sequence number in the forwarded TSN. This
1904 * information will enable the receiver to easily find any
1905 * stranded TSN's waiting on stream reorder queues. Each stream
1906 * SHOULD only be reported once; this means that if multiple
1907 * abandoned messages occur in the same stream then only the
1908 * highest abandoned stream sequence number is reported. If the
1909 * total size of the FORWARD TSN does NOT fit in a single MTU then
1910 * the sender of the FORWARD TSN SHOULD lower the
1911 * Advanced.Peer.Ack.Point to the last TSN that will fit in a
1912 * single MTU.
1913 */
1914 if (asoc->adv_peer_ack_point > ctsn)
1915 ftsn_chunk = sctp_make_fwdtsn(asoc, asoc->adv_peer_ack_point,
1916 nskips, &ftsn_skip_arr[0]);
1917
1918 if (ftsn_chunk) {
1919 list_add_tail(&ftsn_chunk->list, &q->control_chunk_list);
1920 SCTP_INC_STATS(asoc->base.net, SCTP_MIB_OUTCTRLCHUNKS);
1921 }
1922}