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1/* SCTP kernel implementation
2 * (C) Copyright IBM Corp. 2001, 2004
3 * Copyright (c) 1999-2000 Cisco, Inc.
4 * Copyright (c) 1999-2001 Motorola, Inc.
5 * Copyright (c) 2001-2003 Intel Corp.
6 *
7 * This file is part of the SCTP kernel implementation
8 *
9 * These functions implement the sctp_outq class. The outqueue handles
10 * bundling and queueing of outgoing SCTP chunks.
11 *
12 * This SCTP implementation is free software;
13 * you can redistribute it and/or modify it under the terms of
14 * the GNU General Public License as published by
15 * the Free Software Foundation; either version 2, or (at your option)
16 * any later version.
17 *
18 * This SCTP implementation is distributed in the hope that it
19 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
20 * ************************
21 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
22 * See the GNU General Public License for more details.
23 *
24 * You should have received a copy of the GNU General Public License
25 * along with GNU CC; see the file COPYING. If not, write to
26 * the Free Software Foundation, 59 Temple Place - Suite 330,
27 * Boston, MA 02111-1307, USA.
28 *
29 * Please send any bug reports or fixes you make to the
30 * email address(es):
31 * lksctp developers <lksctp-developers@lists.sourceforge.net>
32 *
33 * Or submit a bug report through the following website:
34 * http://www.sf.net/projects/lksctp
35 *
36 * Written or modified by:
37 * La Monte H.P. Yarroll <piggy@acm.org>
38 * Karl Knutson <karl@athena.chicago.il.us>
39 * Perry Melange <pmelange@null.cc.uic.edu>
40 * Xingang Guo <xingang.guo@intel.com>
41 * Hui Huang <hui.huang@nokia.com>
42 * Sridhar Samudrala <sri@us.ibm.com>
43 * Jon Grimm <jgrimm@us.ibm.com>
44 *
45 * Any bugs reported given to us we will try to fix... any fixes shared will
46 * be incorporated into the next SCTP release.
47 */
48
49#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
50
51#include <linux/types.h>
52#include <linux/list.h> /* For struct list_head */
53#include <linux/socket.h>
54#include <linux/ip.h>
55#include <linux/slab.h>
56#include <net/sock.h> /* For skb_set_owner_w */
57
58#include <net/sctp/sctp.h>
59#include <net/sctp/sm.h>
60
61/* Declare internal functions here. */
62static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn);
63static void sctp_check_transmitted(struct sctp_outq *q,
64 struct list_head *transmitted_queue,
65 struct sctp_transport *transport,
66 struct sctp_sackhdr *sack,
67 __u32 *highest_new_tsn);
68
69static void sctp_mark_missing(struct sctp_outq *q,
70 struct list_head *transmitted_queue,
71 struct sctp_transport *transport,
72 __u32 highest_new_tsn,
73 int count_of_newacks);
74
75static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 sack_ctsn);
76
77static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout);
78
79/* Add data to the front of the queue. */
80static inline void sctp_outq_head_data(struct sctp_outq *q,
81 struct sctp_chunk *ch)
82{
83 list_add(&ch->list, &q->out_chunk_list);
84 q->out_qlen += ch->skb->len;
85}
86
87/* Take data from the front of the queue. */
88static inline struct sctp_chunk *sctp_outq_dequeue_data(struct sctp_outq *q)
89{
90 struct sctp_chunk *ch = NULL;
91
92 if (!list_empty(&q->out_chunk_list)) {
93 struct list_head *entry = q->out_chunk_list.next;
94
95 ch = list_entry(entry, struct sctp_chunk, list);
96 list_del_init(entry);
97 q->out_qlen -= ch->skb->len;
98 }
99 return ch;
100}
101/* Add data chunk to the end of the queue. */
102static inline void sctp_outq_tail_data(struct sctp_outq *q,
103 struct sctp_chunk *ch)
104{
105 list_add_tail(&ch->list, &q->out_chunk_list);
106 q->out_qlen += ch->skb->len;
107}
108
109/*
110 * SFR-CACC algorithm:
111 * D) If count_of_newacks is greater than or equal to 2
112 * and t was not sent to the current primary then the
113 * sender MUST NOT increment missing report count for t.
114 */
115static inline int sctp_cacc_skip_3_1_d(struct sctp_transport *primary,
116 struct sctp_transport *transport,
117 int count_of_newacks)
118{
119 if (count_of_newacks >=2 && transport != primary)
120 return 1;
121 return 0;
122}
123
124/*
125 * SFR-CACC algorithm:
126 * F) If count_of_newacks is less than 2, let d be the
127 * destination to which t was sent. If cacc_saw_newack
128 * is 0 for destination d, then the sender MUST NOT
129 * increment missing report count for t.
130 */
131static inline int sctp_cacc_skip_3_1_f(struct sctp_transport *transport,
132 int count_of_newacks)
133{
134 if (count_of_newacks < 2 &&
135 (transport && !transport->cacc.cacc_saw_newack))
136 return 1;
137 return 0;
138}
139
140/*
141 * SFR-CACC algorithm:
142 * 3.1) If CYCLING_CHANGEOVER is 0, the sender SHOULD
143 * execute steps C, D, F.
144 *
145 * C has been implemented in sctp_outq_sack
146 */
147static inline int sctp_cacc_skip_3_1(struct sctp_transport *primary,
148 struct sctp_transport *transport,
149 int count_of_newacks)
150{
151 if (!primary->cacc.cycling_changeover) {
152 if (sctp_cacc_skip_3_1_d(primary, transport, count_of_newacks))
153 return 1;
154 if (sctp_cacc_skip_3_1_f(transport, count_of_newacks))
155 return 1;
156 return 0;
157 }
158 return 0;
159}
160
161/*
162 * SFR-CACC algorithm:
163 * 3.2) Else if CYCLING_CHANGEOVER is 1, and t is less
164 * than next_tsn_at_change of the current primary, then
165 * the sender MUST NOT increment missing report count
166 * for t.
167 */
168static inline int sctp_cacc_skip_3_2(struct sctp_transport *primary, __u32 tsn)
169{
170 if (primary->cacc.cycling_changeover &&
171 TSN_lt(tsn, primary->cacc.next_tsn_at_change))
172 return 1;
173 return 0;
174}
175
176/*
177 * SFR-CACC algorithm:
178 * 3) If the missing report count for TSN t is to be
179 * incremented according to [RFC2960] and
180 * [SCTP_STEWART-2002], and CHANGEOVER_ACTIVE is set,
181 * then the sender MUST further execute steps 3.1 and
182 * 3.2 to determine if the missing report count for
183 * TSN t SHOULD NOT be incremented.
184 *
185 * 3.3) If 3.1 and 3.2 do not dictate that the missing
186 * report count for t should not be incremented, then
187 * the sender SHOULD increment missing report count for
188 * t (according to [RFC2960] and [SCTP_STEWART_2002]).
189 */
190static inline int sctp_cacc_skip(struct sctp_transport *primary,
191 struct sctp_transport *transport,
192 int count_of_newacks,
193 __u32 tsn)
194{
195 if (primary->cacc.changeover_active &&
196 (sctp_cacc_skip_3_1(primary, transport, count_of_newacks) ||
197 sctp_cacc_skip_3_2(primary, tsn)))
198 return 1;
199 return 0;
200}
201
202/* Initialize an existing sctp_outq. This does the boring stuff.
203 * You still need to define handlers if you really want to DO
204 * something with this structure...
205 */
206void sctp_outq_init(struct sctp_association *asoc, struct sctp_outq *q)
207{
208 q->asoc = asoc;
209 INIT_LIST_HEAD(&q->out_chunk_list);
210 INIT_LIST_HEAD(&q->control_chunk_list);
211 INIT_LIST_HEAD(&q->retransmit);
212 INIT_LIST_HEAD(&q->sacked);
213 INIT_LIST_HEAD(&q->abandoned);
214
215 q->fast_rtx = 0;
216 q->outstanding_bytes = 0;
217 q->empty = 1;
218 q->cork = 0;
219
220 q->malloced = 0;
221 q->out_qlen = 0;
222}
223
224/* Free the outqueue structure and any related pending chunks.
225 */
226void sctp_outq_teardown(struct sctp_outq *q)
227{
228 struct sctp_transport *transport;
229 struct list_head *lchunk, *temp;
230 struct sctp_chunk *chunk, *tmp;
231
232 /* Throw away unacknowledged chunks. */
233 list_for_each_entry(transport, &q->asoc->peer.transport_addr_list,
234 transports) {
235 while ((lchunk = sctp_list_dequeue(&transport->transmitted)) != NULL) {
236 chunk = list_entry(lchunk, struct sctp_chunk,
237 transmitted_list);
238 /* Mark as part of a failed message. */
239 sctp_chunk_fail(chunk, q->error);
240 sctp_chunk_free(chunk);
241 }
242 }
243
244 /* Throw away chunks that have been gap ACKed. */
245 list_for_each_safe(lchunk, temp, &q->sacked) {
246 list_del_init(lchunk);
247 chunk = list_entry(lchunk, struct sctp_chunk,
248 transmitted_list);
249 sctp_chunk_fail(chunk, q->error);
250 sctp_chunk_free(chunk);
251 }
252
253 /* Throw away any chunks in the retransmit queue. */
254 list_for_each_safe(lchunk, temp, &q->retransmit) {
255 list_del_init(lchunk);
256 chunk = list_entry(lchunk, struct sctp_chunk,
257 transmitted_list);
258 sctp_chunk_fail(chunk, q->error);
259 sctp_chunk_free(chunk);
260 }
261
262 /* Throw away any chunks that are in the abandoned queue. */
263 list_for_each_safe(lchunk, temp, &q->abandoned) {
264 list_del_init(lchunk);
265 chunk = list_entry(lchunk, struct sctp_chunk,
266 transmitted_list);
267 sctp_chunk_fail(chunk, q->error);
268 sctp_chunk_free(chunk);
269 }
270
271 /* Throw away any leftover data chunks. */
272 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) {
273
274 /* Mark as send failure. */
275 sctp_chunk_fail(chunk, q->error);
276 sctp_chunk_free(chunk);
277 }
278
279 q->error = 0;
280
281 /* Throw away any leftover control chunks. */
282 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) {
283 list_del_init(&chunk->list);
284 sctp_chunk_free(chunk);
285 }
286}
287
288/* Free the outqueue structure and any related pending chunks. */
289void sctp_outq_free(struct sctp_outq *q)
290{
291 /* Throw away leftover chunks. */
292 sctp_outq_teardown(q);
293
294 /* If we were kmalloc()'d, free the memory. */
295 if (q->malloced)
296 kfree(q);
297}
298
299/* Put a new chunk in an sctp_outq. */
300int sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk)
301{
302 int error = 0;
303
304 SCTP_DEBUG_PRINTK("sctp_outq_tail(%p, %p[%s])\n",
305 q, chunk, chunk && chunk->chunk_hdr ?
306 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type))
307 : "Illegal Chunk");
308
309 /* If it is data, queue it up, otherwise, send it
310 * immediately.
311 */
312 if (sctp_chunk_is_data(chunk)) {
313 /* Is it OK to queue data chunks? */
314 /* From 9. Termination of Association
315 *
316 * When either endpoint performs a shutdown, the
317 * association on each peer will stop accepting new
318 * data from its user and only deliver data in queue
319 * at the time of sending or receiving the SHUTDOWN
320 * chunk.
321 */
322 switch (q->asoc->state) {
323 case SCTP_STATE_CLOSED:
324 case SCTP_STATE_SHUTDOWN_PENDING:
325 case SCTP_STATE_SHUTDOWN_SENT:
326 case SCTP_STATE_SHUTDOWN_RECEIVED:
327 case SCTP_STATE_SHUTDOWN_ACK_SENT:
328 /* Cannot send after transport endpoint shutdown */
329 error = -ESHUTDOWN;
330 break;
331
332 default:
333 SCTP_DEBUG_PRINTK("outqueueing (%p, %p[%s])\n",
334 q, chunk, chunk && chunk->chunk_hdr ?
335 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type))
336 : "Illegal Chunk");
337
338 sctp_outq_tail_data(q, chunk);
339 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED)
340 SCTP_INC_STATS(SCTP_MIB_OUTUNORDERCHUNKS);
341 else
342 SCTP_INC_STATS(SCTP_MIB_OUTORDERCHUNKS);
343 q->empty = 0;
344 break;
345 }
346 } else {
347 list_add_tail(&chunk->list, &q->control_chunk_list);
348 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
349 }
350
351 if (error < 0)
352 return error;
353
354 if (!q->cork)
355 error = sctp_outq_flush(q, 0);
356
357 return error;
358}
359
360/* Insert a chunk into the sorted list based on the TSNs. The retransmit list
361 * and the abandoned list are in ascending order.
362 */
363static void sctp_insert_list(struct list_head *head, struct list_head *new)
364{
365 struct list_head *pos;
366 struct sctp_chunk *nchunk, *lchunk;
367 __u32 ntsn, ltsn;
368 int done = 0;
369
370 nchunk = list_entry(new, struct sctp_chunk, transmitted_list);
371 ntsn = ntohl(nchunk->subh.data_hdr->tsn);
372
373 list_for_each(pos, head) {
374 lchunk = list_entry(pos, struct sctp_chunk, transmitted_list);
375 ltsn = ntohl(lchunk->subh.data_hdr->tsn);
376 if (TSN_lt(ntsn, ltsn)) {
377 list_add(new, pos->prev);
378 done = 1;
379 break;
380 }
381 }
382 if (!done)
383 list_add_tail(new, head);
384}
385
386/* Mark all the eligible packets on a transport for retransmission. */
387void sctp_retransmit_mark(struct sctp_outq *q,
388 struct sctp_transport *transport,
389 __u8 reason)
390{
391 struct list_head *lchunk, *ltemp;
392 struct sctp_chunk *chunk;
393
394 /* Walk through the specified transmitted queue. */
395 list_for_each_safe(lchunk, ltemp, &transport->transmitted) {
396 chunk = list_entry(lchunk, struct sctp_chunk,
397 transmitted_list);
398
399 /* If the chunk is abandoned, move it to abandoned list. */
400 if (sctp_chunk_abandoned(chunk)) {
401 list_del_init(lchunk);
402 sctp_insert_list(&q->abandoned, lchunk);
403
404 /* If this chunk has not been previousely acked,
405 * stop considering it 'outstanding'. Our peer
406 * will most likely never see it since it will
407 * not be retransmitted
408 */
409 if (!chunk->tsn_gap_acked) {
410 if (chunk->transport)
411 chunk->transport->flight_size -=
412 sctp_data_size(chunk);
413 q->outstanding_bytes -= sctp_data_size(chunk);
414 q->asoc->peer.rwnd += (sctp_data_size(chunk) +
415 sizeof(struct sk_buff));
416 }
417 continue;
418 }
419
420 /* If we are doing retransmission due to a timeout or pmtu
421 * discovery, only the chunks that are not yet acked should
422 * be added to the retransmit queue.
423 */
424 if ((reason == SCTP_RTXR_FAST_RTX &&
425 (chunk->fast_retransmit == SCTP_NEED_FRTX)) ||
426 (reason != SCTP_RTXR_FAST_RTX && !chunk->tsn_gap_acked)) {
427 /* RFC 2960 6.2.1 Processing a Received SACK
428 *
429 * C) Any time a DATA chunk is marked for
430 * retransmission (via either T3-rtx timer expiration
431 * (Section 6.3.3) or via fast retransmit
432 * (Section 7.2.4)), add the data size of those
433 * chunks to the rwnd.
434 */
435 q->asoc->peer.rwnd += (sctp_data_size(chunk) +
436 sizeof(struct sk_buff));
437 q->outstanding_bytes -= sctp_data_size(chunk);
438 if (chunk->transport)
439 transport->flight_size -= sctp_data_size(chunk);
440
441 /* sctpimpguide-05 Section 2.8.2
442 * M5) If a T3-rtx timer expires, the
443 * 'TSN.Missing.Report' of all affected TSNs is set
444 * to 0.
445 */
446 chunk->tsn_missing_report = 0;
447
448 /* If a chunk that is being used for RTT measurement
449 * has to be retransmitted, we cannot use this chunk
450 * anymore for RTT measurements. Reset rto_pending so
451 * that a new RTT measurement is started when a new
452 * data chunk is sent.
453 */
454 if (chunk->rtt_in_progress) {
455 chunk->rtt_in_progress = 0;
456 transport->rto_pending = 0;
457 }
458
459 /* Move the chunk to the retransmit queue. The chunks
460 * on the retransmit queue are always kept in order.
461 */
462 list_del_init(lchunk);
463 sctp_insert_list(&q->retransmit, lchunk);
464 }
465 }
466
467 SCTP_DEBUG_PRINTK("%s: transport: %p, reason: %d, "
468 "cwnd: %d, ssthresh: %d, flight_size: %d, "
469 "pba: %d\n", __func__,
470 transport, reason,
471 transport->cwnd, transport->ssthresh,
472 transport->flight_size,
473 transport->partial_bytes_acked);
474
475}
476
477/* Mark all the eligible packets on a transport for retransmission and force
478 * one packet out.
479 */
480void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
481 sctp_retransmit_reason_t reason)
482{
483 int error = 0;
484
485 switch(reason) {
486 case SCTP_RTXR_T3_RTX:
487 SCTP_INC_STATS(SCTP_MIB_T3_RETRANSMITS);
488 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_T3_RTX);
489 /* Update the retran path if the T3-rtx timer has expired for
490 * the current retran path.
491 */
492 if (transport == transport->asoc->peer.retran_path)
493 sctp_assoc_update_retran_path(transport->asoc);
494 transport->asoc->rtx_data_chunks +=
495 transport->asoc->unack_data;
496 break;
497 case SCTP_RTXR_FAST_RTX:
498 SCTP_INC_STATS(SCTP_MIB_FAST_RETRANSMITS);
499 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_FAST_RTX);
500 q->fast_rtx = 1;
501 break;
502 case SCTP_RTXR_PMTUD:
503 SCTP_INC_STATS(SCTP_MIB_PMTUD_RETRANSMITS);
504 break;
505 case SCTP_RTXR_T1_RTX:
506 SCTP_INC_STATS(SCTP_MIB_T1_RETRANSMITS);
507 transport->asoc->init_retries++;
508 break;
509 default:
510 BUG();
511 }
512
513 sctp_retransmit_mark(q, transport, reason);
514
515 /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination,
516 * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by
517 * following the procedures outlined in C1 - C5.
518 */
519 if (reason == SCTP_RTXR_T3_RTX)
520 sctp_generate_fwdtsn(q, q->asoc->ctsn_ack_point);
521
522 /* Flush the queues only on timeout, since fast_rtx is only
523 * triggered during sack processing and the queue
524 * will be flushed at the end.
525 */
526 if (reason != SCTP_RTXR_FAST_RTX)
527 error = sctp_outq_flush(q, /* rtx_timeout */ 1);
528
529 if (error)
530 q->asoc->base.sk->sk_err = -error;
531}
532
533/*
534 * Transmit DATA chunks on the retransmit queue. Upon return from
535 * sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which
536 * need to be transmitted by the caller.
537 * We assume that pkt->transport has already been set.
538 *
539 * The return value is a normal kernel error return value.
540 */
541static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
542 int rtx_timeout, int *start_timer)
543{
544 struct list_head *lqueue;
545 struct sctp_transport *transport = pkt->transport;
546 sctp_xmit_t status;
547 struct sctp_chunk *chunk, *chunk1;
548 int fast_rtx;
549 int error = 0;
550 int timer = 0;
551 int done = 0;
552
553 lqueue = &q->retransmit;
554 fast_rtx = q->fast_rtx;
555
556 /* This loop handles time-out retransmissions, fast retransmissions,
557 * and retransmissions due to opening of whindow.
558 *
559 * RFC 2960 6.3.3 Handle T3-rtx Expiration
560 *
561 * E3) Determine how many of the earliest (i.e., lowest TSN)
562 * outstanding DATA chunks for the address for which the
563 * T3-rtx has expired will fit into a single packet, subject
564 * to the MTU constraint for the path corresponding to the
565 * destination transport address to which the retransmission
566 * is being sent (this may be different from the address for
567 * which the timer expires [see Section 6.4]). Call this value
568 * K. Bundle and retransmit those K DATA chunks in a single
569 * packet to the destination endpoint.
570 *
571 * [Just to be painfully clear, if we are retransmitting
572 * because a timeout just happened, we should send only ONE
573 * packet of retransmitted data.]
574 *
575 * For fast retransmissions we also send only ONE packet. However,
576 * if we are just flushing the queue due to open window, we'll
577 * try to send as much as possible.
578 */
579 list_for_each_entry_safe(chunk, chunk1, lqueue, transmitted_list) {
580 /* If the chunk is abandoned, move it to abandoned list. */
581 if (sctp_chunk_abandoned(chunk)) {
582 list_del_init(&chunk->transmitted_list);
583 sctp_insert_list(&q->abandoned,
584 &chunk->transmitted_list);
585 continue;
586 }
587
588 /* Make sure that Gap Acked TSNs are not retransmitted. A
589 * simple approach is just to move such TSNs out of the
590 * way and into a 'transmitted' queue and skip to the
591 * next chunk.
592 */
593 if (chunk->tsn_gap_acked) {
594 list_del(&chunk->transmitted_list);
595 list_add_tail(&chunk->transmitted_list,
596 &transport->transmitted);
597 continue;
598 }
599
600 /* If we are doing fast retransmit, ignore non-fast_rtransmit
601 * chunks
602 */
603 if (fast_rtx && !chunk->fast_retransmit)
604 continue;
605
606redo:
607 /* Attempt to append this chunk to the packet. */
608 status = sctp_packet_append_chunk(pkt, chunk);
609
610 switch (status) {
611 case SCTP_XMIT_PMTU_FULL:
612 if (!pkt->has_data && !pkt->has_cookie_echo) {
613 /* If this packet did not contain DATA then
614 * retransmission did not happen, so do it
615 * again. We'll ignore the error here since
616 * control chunks are already freed so there
617 * is nothing we can do.
618 */
619 sctp_packet_transmit(pkt);
620 goto redo;
621 }
622
623 /* Send this packet. */
624 error = sctp_packet_transmit(pkt);
625
626 /* If we are retransmitting, we should only
627 * send a single packet.
628 * Otherwise, try appending this chunk again.
629 */
630 if (rtx_timeout || fast_rtx)
631 done = 1;
632 else
633 goto redo;
634
635 /* Bundle next chunk in the next round. */
636 break;
637
638 case SCTP_XMIT_RWND_FULL:
639 /* Send this packet. */
640 error = sctp_packet_transmit(pkt);
641
642 /* Stop sending DATA as there is no more room
643 * at the receiver.
644 */
645 done = 1;
646 break;
647
648 case SCTP_XMIT_NAGLE_DELAY:
649 /* Send this packet. */
650 error = sctp_packet_transmit(pkt);
651
652 /* Stop sending DATA because of nagle delay. */
653 done = 1;
654 break;
655
656 default:
657 /* The append was successful, so add this chunk to
658 * the transmitted list.
659 */
660 list_del(&chunk->transmitted_list);
661 list_add_tail(&chunk->transmitted_list,
662 &transport->transmitted);
663
664 /* Mark the chunk as ineligible for fast retransmit
665 * after it is retransmitted.
666 */
667 if (chunk->fast_retransmit == SCTP_NEED_FRTX)
668 chunk->fast_retransmit = SCTP_DONT_FRTX;
669
670 q->empty = 0;
671 break;
672 }
673
674 /* Set the timer if there were no errors */
675 if (!error && !timer)
676 timer = 1;
677
678 if (done)
679 break;
680 }
681
682 /* If we are here due to a retransmit timeout or a fast
683 * retransmit and if there are any chunks left in the retransmit
684 * queue that could not fit in the PMTU sized packet, they need
685 * to be marked as ineligible for a subsequent fast retransmit.
686 */
687 if (rtx_timeout || fast_rtx) {
688 list_for_each_entry(chunk1, lqueue, transmitted_list) {
689 if (chunk1->fast_retransmit == SCTP_NEED_FRTX)
690 chunk1->fast_retransmit = SCTP_DONT_FRTX;
691 }
692 }
693
694 *start_timer = timer;
695
696 /* Clear fast retransmit hint */
697 if (fast_rtx)
698 q->fast_rtx = 0;
699
700 return error;
701}
702
703/* Cork the outqueue so queued chunks are really queued. */
704int sctp_outq_uncork(struct sctp_outq *q)
705{
706 int error = 0;
707 if (q->cork)
708 q->cork = 0;
709 error = sctp_outq_flush(q, 0);
710 return error;
711}
712
713
714/*
715 * Try to flush an outqueue.
716 *
717 * Description: Send everything in q which we legally can, subject to
718 * congestion limitations.
719 * * Note: This function can be called from multiple contexts so appropriate
720 * locking concerns must be made. Today we use the sock lock to protect
721 * this function.
722 */
723static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout)
724{
725 struct sctp_packet *packet;
726 struct sctp_packet singleton;
727 struct sctp_association *asoc = q->asoc;
728 __u16 sport = asoc->base.bind_addr.port;
729 __u16 dport = asoc->peer.port;
730 __u32 vtag = asoc->peer.i.init_tag;
731 struct sctp_transport *transport = NULL;
732 struct sctp_transport *new_transport;
733 struct sctp_chunk *chunk, *tmp;
734 sctp_xmit_t status;
735 int error = 0;
736 int start_timer = 0;
737 int one_packet = 0;
738
739 /* These transports have chunks to send. */
740 struct list_head transport_list;
741 struct list_head *ltransport;
742
743 INIT_LIST_HEAD(&transport_list);
744 packet = NULL;
745
746 /*
747 * 6.10 Bundling
748 * ...
749 * When bundling control chunks with DATA chunks, an
750 * endpoint MUST place control chunks first in the outbound
751 * SCTP packet. The transmitter MUST transmit DATA chunks
752 * within a SCTP packet in increasing order of TSN.
753 * ...
754 */
755
756 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) {
757 /* RFC 5061, 5.3
758 * F1) This means that until such time as the ASCONF
759 * containing the add is acknowledged, the sender MUST
760 * NOT use the new IP address as a source for ANY SCTP
761 * packet except on carrying an ASCONF Chunk.
762 */
763 if (asoc->src_out_of_asoc_ok &&
764 chunk->chunk_hdr->type != SCTP_CID_ASCONF)
765 continue;
766
767 list_del_init(&chunk->list);
768
769 /* Pick the right transport to use. */
770 new_transport = chunk->transport;
771
772 if (!new_transport) {
773 /*
774 * If we have a prior transport pointer, see if
775 * the destination address of the chunk
776 * matches the destination address of the
777 * current transport. If not a match, then
778 * try to look up the transport with a given
779 * destination address. We do this because
780 * after processing ASCONFs, we may have new
781 * transports created.
782 */
783 if (transport &&
784 sctp_cmp_addr_exact(&chunk->dest,
785 &transport->ipaddr))
786 new_transport = transport;
787 else
788 new_transport = sctp_assoc_lookup_paddr(asoc,
789 &chunk->dest);
790
791 /* if we still don't have a new transport, then
792 * use the current active path.
793 */
794 if (!new_transport)
795 new_transport = asoc->peer.active_path;
796 } else if ((new_transport->state == SCTP_INACTIVE) ||
797 (new_transport->state == SCTP_UNCONFIRMED)) {
798 /* If the chunk is Heartbeat or Heartbeat Ack,
799 * send it to chunk->transport, even if it's
800 * inactive.
801 *
802 * 3.3.6 Heartbeat Acknowledgement:
803 * ...
804 * A HEARTBEAT ACK is always sent to the source IP
805 * address of the IP datagram containing the
806 * HEARTBEAT chunk to which this ack is responding.
807 * ...
808 *
809 * ASCONF_ACKs also must be sent to the source.
810 */
811 if (chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT &&
812 chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT_ACK &&
813 chunk->chunk_hdr->type != SCTP_CID_ASCONF_ACK)
814 new_transport = asoc->peer.active_path;
815 }
816
817 /* Are we switching transports?
818 * Take care of transport locks.
819 */
820 if (new_transport != transport) {
821 transport = new_transport;
822 if (list_empty(&transport->send_ready)) {
823 list_add_tail(&transport->send_ready,
824 &transport_list);
825 }
826 packet = &transport->packet;
827 sctp_packet_config(packet, vtag,
828 asoc->peer.ecn_capable);
829 }
830
831 switch (chunk->chunk_hdr->type) {
832 /*
833 * 6.10 Bundling
834 * ...
835 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN
836 * COMPLETE with any other chunks. [Send them immediately.]
837 */
838 case SCTP_CID_INIT:
839 case SCTP_CID_INIT_ACK:
840 case SCTP_CID_SHUTDOWN_COMPLETE:
841 sctp_packet_init(&singleton, transport, sport, dport);
842 sctp_packet_config(&singleton, vtag, 0);
843 sctp_packet_append_chunk(&singleton, chunk);
844 error = sctp_packet_transmit(&singleton);
845 if (error < 0)
846 return error;
847 break;
848
849 case SCTP_CID_ABORT:
850 if (sctp_test_T_bit(chunk)) {
851 packet->vtag = asoc->c.my_vtag;
852 }
853 /* The following chunks are "response" chunks, i.e.
854 * they are generated in response to something we
855 * received. If we are sending these, then we can
856 * send only 1 packet containing these chunks.
857 */
858 case SCTP_CID_HEARTBEAT_ACK:
859 case SCTP_CID_SHUTDOWN_ACK:
860 case SCTP_CID_COOKIE_ACK:
861 case SCTP_CID_COOKIE_ECHO:
862 case SCTP_CID_ERROR:
863 case SCTP_CID_ECN_CWR:
864 case SCTP_CID_ASCONF_ACK:
865 one_packet = 1;
866 /* Fall through */
867
868 case SCTP_CID_SACK:
869 case SCTP_CID_HEARTBEAT:
870 case SCTP_CID_SHUTDOWN:
871 case SCTP_CID_ECN_ECNE:
872 case SCTP_CID_ASCONF:
873 case SCTP_CID_FWD_TSN:
874 status = sctp_packet_transmit_chunk(packet, chunk,
875 one_packet);
876 if (status != SCTP_XMIT_OK) {
877 /* put the chunk back */
878 list_add(&chunk->list, &q->control_chunk_list);
879 } else if (chunk->chunk_hdr->type == SCTP_CID_FWD_TSN) {
880 /* PR-SCTP C5) If a FORWARD TSN is sent, the
881 * sender MUST assure that at least one T3-rtx
882 * timer is running.
883 */
884 sctp_transport_reset_timers(transport);
885 }
886 break;
887
888 default:
889 /* We built a chunk with an illegal type! */
890 BUG();
891 }
892 }
893
894 if (q->asoc->src_out_of_asoc_ok)
895 goto sctp_flush_out;
896
897 /* Is it OK to send data chunks? */
898 switch (asoc->state) {
899 case SCTP_STATE_COOKIE_ECHOED:
900 /* Only allow bundling when this packet has a COOKIE-ECHO
901 * chunk.
902 */
903 if (!packet || !packet->has_cookie_echo)
904 break;
905
906 /* fallthru */
907 case SCTP_STATE_ESTABLISHED:
908 case SCTP_STATE_SHUTDOWN_PENDING:
909 case SCTP_STATE_SHUTDOWN_RECEIVED:
910 /*
911 * RFC 2960 6.1 Transmission of DATA Chunks
912 *
913 * C) When the time comes for the sender to transmit,
914 * before sending new DATA chunks, the sender MUST
915 * first transmit any outstanding DATA chunks which
916 * are marked for retransmission (limited by the
917 * current cwnd).
918 */
919 if (!list_empty(&q->retransmit)) {
920 if (transport == asoc->peer.retran_path)
921 goto retran;
922
923 /* Switch transports & prepare the packet. */
924
925 transport = asoc->peer.retran_path;
926
927 if (list_empty(&transport->send_ready)) {
928 list_add_tail(&transport->send_ready,
929 &transport_list);
930 }
931
932 packet = &transport->packet;
933 sctp_packet_config(packet, vtag,
934 asoc->peer.ecn_capable);
935 retran:
936 error = sctp_outq_flush_rtx(q, packet,
937 rtx_timeout, &start_timer);
938
939 if (start_timer)
940 sctp_transport_reset_timers(transport);
941
942 /* This can happen on COOKIE-ECHO resend. Only
943 * one chunk can get bundled with a COOKIE-ECHO.
944 */
945 if (packet->has_cookie_echo)
946 goto sctp_flush_out;
947
948 /* Don't send new data if there is still data
949 * waiting to retransmit.
950 */
951 if (!list_empty(&q->retransmit))
952 goto sctp_flush_out;
953 }
954
955 /* Apply Max.Burst limitation to the current transport in
956 * case it will be used for new data. We are going to
957 * rest it before we return, but we want to apply the limit
958 * to the currently queued data.
959 */
960 if (transport)
961 sctp_transport_burst_limited(transport);
962
963 /* Finally, transmit new packets. */
964 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) {
965 /* RFC 2960 6.5 Every DATA chunk MUST carry a valid
966 * stream identifier.
967 */
968 if (chunk->sinfo.sinfo_stream >=
969 asoc->c.sinit_num_ostreams) {
970
971 /* Mark as failed send. */
972 sctp_chunk_fail(chunk, SCTP_ERROR_INV_STRM);
973 sctp_chunk_free(chunk);
974 continue;
975 }
976
977 /* Has this chunk expired? */
978 if (sctp_chunk_abandoned(chunk)) {
979 sctp_chunk_fail(chunk, 0);
980 sctp_chunk_free(chunk);
981 continue;
982 }
983
984 /* If there is a specified transport, use it.
985 * Otherwise, we want to use the active path.
986 */
987 new_transport = chunk->transport;
988 if (!new_transport ||
989 ((new_transport->state == SCTP_INACTIVE) ||
990 (new_transport->state == SCTP_UNCONFIRMED)))
991 new_transport = asoc->peer.active_path;
992
993 /* Change packets if necessary. */
994 if (new_transport != transport) {
995 transport = new_transport;
996
997 /* Schedule to have this transport's
998 * packet flushed.
999 */
1000 if (list_empty(&transport->send_ready)) {
1001 list_add_tail(&transport->send_ready,
1002 &transport_list);
1003 }
1004
1005 packet = &transport->packet;
1006 sctp_packet_config(packet, vtag,
1007 asoc->peer.ecn_capable);
1008 /* We've switched transports, so apply the
1009 * Burst limit to the new transport.
1010 */
1011 sctp_transport_burst_limited(transport);
1012 }
1013
1014 SCTP_DEBUG_PRINTK("sctp_outq_flush(%p, %p[%s]), ",
1015 q, chunk,
1016 chunk && chunk->chunk_hdr ?
1017 sctp_cname(SCTP_ST_CHUNK(
1018 chunk->chunk_hdr->type))
1019 : "Illegal Chunk");
1020
1021 SCTP_DEBUG_PRINTK("TX TSN 0x%x skb->head "
1022 "%p skb->users %d.\n",
1023 ntohl(chunk->subh.data_hdr->tsn),
1024 chunk->skb ?chunk->skb->head : NULL,
1025 chunk->skb ?
1026 atomic_read(&chunk->skb->users) : -1);
1027
1028 /* Add the chunk to the packet. */
1029 status = sctp_packet_transmit_chunk(packet, chunk, 0);
1030
1031 switch (status) {
1032 case SCTP_XMIT_PMTU_FULL:
1033 case SCTP_XMIT_RWND_FULL:
1034 case SCTP_XMIT_NAGLE_DELAY:
1035 /* We could not append this chunk, so put
1036 * the chunk back on the output queue.
1037 */
1038 SCTP_DEBUG_PRINTK("sctp_outq_flush: could "
1039 "not transmit TSN: 0x%x, status: %d\n",
1040 ntohl(chunk->subh.data_hdr->tsn),
1041 status);
1042 sctp_outq_head_data(q, chunk);
1043 goto sctp_flush_out;
1044 break;
1045
1046 case SCTP_XMIT_OK:
1047 /* The sender is in the SHUTDOWN-PENDING state,
1048 * The sender MAY set the I-bit in the DATA
1049 * chunk header.
1050 */
1051 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING)
1052 chunk->chunk_hdr->flags |= SCTP_DATA_SACK_IMM;
1053
1054 break;
1055
1056 default:
1057 BUG();
1058 }
1059
1060 /* BUG: We assume that the sctp_packet_transmit()
1061 * call below will succeed all the time and add the
1062 * chunk to the transmitted list and restart the
1063 * timers.
1064 * It is possible that the call can fail under OOM
1065 * conditions.
1066 *
1067 * Is this really a problem? Won't this behave
1068 * like a lost TSN?
1069 */
1070 list_add_tail(&chunk->transmitted_list,
1071 &transport->transmitted);
1072
1073 sctp_transport_reset_timers(transport);
1074
1075 q->empty = 0;
1076
1077 /* Only let one DATA chunk get bundled with a
1078 * COOKIE-ECHO chunk.
1079 */
1080 if (packet->has_cookie_echo)
1081 goto sctp_flush_out;
1082 }
1083 break;
1084
1085 default:
1086 /* Do nothing. */
1087 break;
1088 }
1089
1090sctp_flush_out:
1091
1092 /* Before returning, examine all the transports touched in
1093 * this call. Right now, we bluntly force clear all the
1094 * transports. Things might change after we implement Nagle.
1095 * But such an examination is still required.
1096 *
1097 * --xguo
1098 */
1099 while ((ltransport = sctp_list_dequeue(&transport_list)) != NULL ) {
1100 struct sctp_transport *t = list_entry(ltransport,
1101 struct sctp_transport,
1102 send_ready);
1103 packet = &t->packet;
1104 if (!sctp_packet_empty(packet))
1105 error = sctp_packet_transmit(packet);
1106
1107 /* Clear the burst limited state, if any */
1108 sctp_transport_burst_reset(t);
1109 }
1110
1111 return error;
1112}
1113
1114/* Update unack_data based on the incoming SACK chunk */
1115static void sctp_sack_update_unack_data(struct sctp_association *assoc,
1116 struct sctp_sackhdr *sack)
1117{
1118 sctp_sack_variable_t *frags;
1119 __u16 unack_data;
1120 int i;
1121
1122 unack_data = assoc->next_tsn - assoc->ctsn_ack_point - 1;
1123
1124 frags = sack->variable;
1125 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); i++) {
1126 unack_data -= ((ntohs(frags[i].gab.end) -
1127 ntohs(frags[i].gab.start) + 1));
1128 }
1129
1130 assoc->unack_data = unack_data;
1131}
1132
1133/* This is where we REALLY process a SACK.
1134 *
1135 * Process the SACK against the outqueue. Mostly, this just frees
1136 * things off the transmitted queue.
1137 */
1138int sctp_outq_sack(struct sctp_outq *q, struct sctp_sackhdr *sack)
1139{
1140 struct sctp_association *asoc = q->asoc;
1141 struct sctp_transport *transport;
1142 struct sctp_chunk *tchunk = NULL;
1143 struct list_head *lchunk, *transport_list, *temp;
1144 sctp_sack_variable_t *frags = sack->variable;
1145 __u32 sack_ctsn, ctsn, tsn;
1146 __u32 highest_tsn, highest_new_tsn;
1147 __u32 sack_a_rwnd;
1148 unsigned outstanding;
1149 struct sctp_transport *primary = asoc->peer.primary_path;
1150 int count_of_newacks = 0;
1151 int gap_ack_blocks;
1152 u8 accum_moved = 0;
1153
1154 /* Grab the association's destination address list. */
1155 transport_list = &asoc->peer.transport_addr_list;
1156
1157 sack_ctsn = ntohl(sack->cum_tsn_ack);
1158 gap_ack_blocks = ntohs(sack->num_gap_ack_blocks);
1159 /*
1160 * SFR-CACC algorithm:
1161 * On receipt of a SACK the sender SHOULD execute the
1162 * following statements.
1163 *
1164 * 1) If the cumulative ack in the SACK passes next tsn_at_change
1165 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be
1166 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for
1167 * all destinations.
1168 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE
1169 * is set the receiver of the SACK MUST take the following actions:
1170 *
1171 * A) Initialize the cacc_saw_newack to 0 for all destination
1172 * addresses.
1173 *
1174 * Only bother if changeover_active is set. Otherwise, this is
1175 * totally suboptimal to do on every SACK.
1176 */
1177 if (primary->cacc.changeover_active) {
1178 u8 clear_cycling = 0;
1179
1180 if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) {
1181 primary->cacc.changeover_active = 0;
1182 clear_cycling = 1;
1183 }
1184
1185 if (clear_cycling || gap_ack_blocks) {
1186 list_for_each_entry(transport, transport_list,
1187 transports) {
1188 if (clear_cycling)
1189 transport->cacc.cycling_changeover = 0;
1190 if (gap_ack_blocks)
1191 transport->cacc.cacc_saw_newack = 0;
1192 }
1193 }
1194 }
1195
1196 /* Get the highest TSN in the sack. */
1197 highest_tsn = sack_ctsn;
1198 if (gap_ack_blocks)
1199 highest_tsn += ntohs(frags[gap_ack_blocks - 1].gab.end);
1200
1201 if (TSN_lt(asoc->highest_sacked, highest_tsn))
1202 asoc->highest_sacked = highest_tsn;
1203
1204 highest_new_tsn = sack_ctsn;
1205
1206 /* Run through the retransmit queue. Credit bytes received
1207 * and free those chunks that we can.
1208 */
1209 sctp_check_transmitted(q, &q->retransmit, NULL, sack, &highest_new_tsn);
1210
1211 /* Run through the transmitted queue.
1212 * Credit bytes received and free those chunks which we can.
1213 *
1214 * This is a MASSIVE candidate for optimization.
1215 */
1216 list_for_each_entry(transport, transport_list, transports) {
1217 sctp_check_transmitted(q, &transport->transmitted,
1218 transport, sack, &highest_new_tsn);
1219 /*
1220 * SFR-CACC algorithm:
1221 * C) Let count_of_newacks be the number of
1222 * destinations for which cacc_saw_newack is set.
1223 */
1224 if (transport->cacc.cacc_saw_newack)
1225 count_of_newacks ++;
1226 }
1227
1228 /* Move the Cumulative TSN Ack Point if appropriate. */
1229 if (TSN_lt(asoc->ctsn_ack_point, sack_ctsn)) {
1230 asoc->ctsn_ack_point = sack_ctsn;
1231 accum_moved = 1;
1232 }
1233
1234 if (gap_ack_blocks) {
1235
1236 if (asoc->fast_recovery && accum_moved)
1237 highest_new_tsn = highest_tsn;
1238
1239 list_for_each_entry(transport, transport_list, transports)
1240 sctp_mark_missing(q, &transport->transmitted, transport,
1241 highest_new_tsn, count_of_newacks);
1242 }
1243
1244 /* Update unack_data field in the assoc. */
1245 sctp_sack_update_unack_data(asoc, sack);
1246
1247 ctsn = asoc->ctsn_ack_point;
1248
1249 /* Throw away stuff rotting on the sack queue. */
1250 list_for_each_safe(lchunk, temp, &q->sacked) {
1251 tchunk = list_entry(lchunk, struct sctp_chunk,
1252 transmitted_list);
1253 tsn = ntohl(tchunk->subh.data_hdr->tsn);
1254 if (TSN_lte(tsn, ctsn)) {
1255 list_del_init(&tchunk->transmitted_list);
1256 sctp_chunk_free(tchunk);
1257 }
1258 }
1259
1260 /* ii) Set rwnd equal to the newly received a_rwnd minus the
1261 * number of bytes still outstanding after processing the
1262 * Cumulative TSN Ack and the Gap Ack Blocks.
1263 */
1264
1265 sack_a_rwnd = ntohl(sack->a_rwnd);
1266 outstanding = q->outstanding_bytes;
1267
1268 if (outstanding < sack_a_rwnd)
1269 sack_a_rwnd -= outstanding;
1270 else
1271 sack_a_rwnd = 0;
1272
1273 asoc->peer.rwnd = sack_a_rwnd;
1274
1275 sctp_generate_fwdtsn(q, sack_ctsn);
1276
1277 SCTP_DEBUG_PRINTK("%s: sack Cumulative TSN Ack is 0x%x.\n",
1278 __func__, sack_ctsn);
1279 SCTP_DEBUG_PRINTK("%s: Cumulative TSN Ack of association, "
1280 "%p is 0x%x. Adv peer ack point: 0x%x\n",
1281 __func__, asoc, ctsn, asoc->adv_peer_ack_point);
1282
1283 /* See if all chunks are acked.
1284 * Make sure the empty queue handler will get run later.
1285 */
1286 q->empty = (list_empty(&q->out_chunk_list) &&
1287 list_empty(&q->retransmit));
1288 if (!q->empty)
1289 goto finish;
1290
1291 list_for_each_entry(transport, transport_list, transports) {
1292 q->empty = q->empty && list_empty(&transport->transmitted);
1293 if (!q->empty)
1294 goto finish;
1295 }
1296
1297 SCTP_DEBUG_PRINTK("sack queue is empty.\n");
1298finish:
1299 return q->empty;
1300}
1301
1302/* Is the outqueue empty? */
1303int sctp_outq_is_empty(const struct sctp_outq *q)
1304{
1305 return q->empty;
1306}
1307
1308/********************************************************************
1309 * 2nd Level Abstractions
1310 ********************************************************************/
1311
1312/* Go through a transport's transmitted list or the association's retransmit
1313 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked.
1314 * The retransmit list will not have an associated transport.
1315 *
1316 * I added coherent debug information output. --xguo
1317 *
1318 * Instead of printing 'sacked' or 'kept' for each TSN on the
1319 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5.
1320 * KEPT TSN6-TSN7, etc.
1321 */
1322static void sctp_check_transmitted(struct sctp_outq *q,
1323 struct list_head *transmitted_queue,
1324 struct sctp_transport *transport,
1325 struct sctp_sackhdr *sack,
1326 __u32 *highest_new_tsn_in_sack)
1327{
1328 struct list_head *lchunk;
1329 struct sctp_chunk *tchunk;
1330 struct list_head tlist;
1331 __u32 tsn;
1332 __u32 sack_ctsn;
1333 __u32 rtt;
1334 __u8 restart_timer = 0;
1335 int bytes_acked = 0;
1336 int migrate_bytes = 0;
1337
1338 /* These state variables are for coherent debug output. --xguo */
1339
1340#if SCTP_DEBUG
1341 __u32 dbg_ack_tsn = 0; /* An ACKed TSN range starts here... */
1342 __u32 dbg_last_ack_tsn = 0; /* ...and finishes here. */
1343 __u32 dbg_kept_tsn = 0; /* An un-ACKed range starts here... */
1344 __u32 dbg_last_kept_tsn = 0; /* ...and finishes here. */
1345
1346 /* 0 : The last TSN was ACKed.
1347 * 1 : The last TSN was NOT ACKed (i.e. KEPT).
1348 * -1: We need to initialize.
1349 */
1350 int dbg_prt_state = -1;
1351#endif /* SCTP_DEBUG */
1352
1353 sack_ctsn = ntohl(sack->cum_tsn_ack);
1354
1355 INIT_LIST_HEAD(&tlist);
1356
1357 /* The while loop will skip empty transmitted queues. */
1358 while (NULL != (lchunk = sctp_list_dequeue(transmitted_queue))) {
1359 tchunk = list_entry(lchunk, struct sctp_chunk,
1360 transmitted_list);
1361
1362 if (sctp_chunk_abandoned(tchunk)) {
1363 /* Move the chunk to abandoned list. */
1364 sctp_insert_list(&q->abandoned, lchunk);
1365
1366 /* If this chunk has not been acked, stop
1367 * considering it as 'outstanding'.
1368 */
1369 if (!tchunk->tsn_gap_acked) {
1370 if (tchunk->transport)
1371 tchunk->transport->flight_size -=
1372 sctp_data_size(tchunk);
1373 q->outstanding_bytes -= sctp_data_size(tchunk);
1374 }
1375 continue;
1376 }
1377
1378 tsn = ntohl(tchunk->subh.data_hdr->tsn);
1379 if (sctp_acked(sack, tsn)) {
1380 /* If this queue is the retransmit queue, the
1381 * retransmit timer has already reclaimed
1382 * the outstanding bytes for this chunk, so only
1383 * count bytes associated with a transport.
1384 */
1385 if (transport) {
1386 /* If this chunk is being used for RTT
1387 * measurement, calculate the RTT and update
1388 * the RTO using this value.
1389 *
1390 * 6.3.1 C5) Karn's algorithm: RTT measurements
1391 * MUST NOT be made using packets that were
1392 * retransmitted (and thus for which it is
1393 * ambiguous whether the reply was for the
1394 * first instance of the packet or a later
1395 * instance).
1396 */
1397 if (!tchunk->tsn_gap_acked &&
1398 tchunk->rtt_in_progress) {
1399 tchunk->rtt_in_progress = 0;
1400 rtt = jiffies - tchunk->sent_at;
1401 sctp_transport_update_rto(transport,
1402 rtt);
1403 }
1404 }
1405
1406 /* If the chunk hasn't been marked as ACKED,
1407 * mark it and account bytes_acked if the
1408 * chunk had a valid transport (it will not
1409 * have a transport if ASCONF had deleted it
1410 * while DATA was outstanding).
1411 */
1412 if (!tchunk->tsn_gap_acked) {
1413 tchunk->tsn_gap_acked = 1;
1414 *highest_new_tsn_in_sack = tsn;
1415 bytes_acked += sctp_data_size(tchunk);
1416 if (!tchunk->transport)
1417 migrate_bytes += sctp_data_size(tchunk);
1418 }
1419
1420 if (TSN_lte(tsn, sack_ctsn)) {
1421 /* RFC 2960 6.3.2 Retransmission Timer Rules
1422 *
1423 * R3) Whenever a SACK is received
1424 * that acknowledges the DATA chunk
1425 * with the earliest outstanding TSN
1426 * for that address, restart T3-rtx
1427 * timer for that address with its
1428 * current RTO.
1429 */
1430 restart_timer = 1;
1431
1432 if (!tchunk->tsn_gap_acked) {
1433 /*
1434 * SFR-CACC algorithm:
1435 * 2) If the SACK contains gap acks
1436 * and the flag CHANGEOVER_ACTIVE is
1437 * set the receiver of the SACK MUST
1438 * take the following action:
1439 *
1440 * B) For each TSN t being acked that
1441 * has not been acked in any SACK so
1442 * far, set cacc_saw_newack to 1 for
1443 * the destination that the TSN was
1444 * sent to.
1445 */
1446 if (transport &&
1447 sack->num_gap_ack_blocks &&
1448 q->asoc->peer.primary_path->cacc.
1449 changeover_active)
1450 transport->cacc.cacc_saw_newack
1451 = 1;
1452 }
1453
1454 list_add_tail(&tchunk->transmitted_list,
1455 &q->sacked);
1456 } else {
1457 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2
1458 * M2) Each time a SACK arrives reporting
1459 * 'Stray DATA chunk(s)' record the highest TSN
1460 * reported as newly acknowledged, call this
1461 * value 'HighestTSNinSack'. A newly
1462 * acknowledged DATA chunk is one not
1463 * previously acknowledged in a SACK.
1464 *
1465 * When the SCTP sender of data receives a SACK
1466 * chunk that acknowledges, for the first time,
1467 * the receipt of a DATA chunk, all the still
1468 * unacknowledged DATA chunks whose TSN is
1469 * older than that newly acknowledged DATA
1470 * chunk, are qualified as 'Stray DATA chunks'.
1471 */
1472 list_add_tail(lchunk, &tlist);
1473 }
1474
1475#if SCTP_DEBUG
1476 switch (dbg_prt_state) {
1477 case 0: /* last TSN was ACKed */
1478 if (dbg_last_ack_tsn + 1 == tsn) {
1479 /* This TSN belongs to the
1480 * current ACK range.
1481 */
1482 break;
1483 }
1484
1485 if (dbg_last_ack_tsn != dbg_ack_tsn) {
1486 /* Display the end of the
1487 * current range.
1488 */
1489 SCTP_DEBUG_PRINTK_CONT("-%08x",
1490 dbg_last_ack_tsn);
1491 }
1492
1493 /* Start a new range. */
1494 SCTP_DEBUG_PRINTK_CONT(",%08x", tsn);
1495 dbg_ack_tsn = tsn;
1496 break;
1497
1498 case 1: /* The last TSN was NOT ACKed. */
1499 if (dbg_last_kept_tsn != dbg_kept_tsn) {
1500 /* Display the end of current range. */
1501 SCTP_DEBUG_PRINTK_CONT("-%08x",
1502 dbg_last_kept_tsn);
1503 }
1504
1505 SCTP_DEBUG_PRINTK_CONT("\n");
1506
1507 /* FALL THROUGH... */
1508 default:
1509 /* This is the first-ever TSN we examined. */
1510 /* Start a new range of ACK-ed TSNs. */
1511 SCTP_DEBUG_PRINTK("ACKed: %08x", tsn);
1512 dbg_prt_state = 0;
1513 dbg_ack_tsn = tsn;
1514 }
1515
1516 dbg_last_ack_tsn = tsn;
1517#endif /* SCTP_DEBUG */
1518
1519 } else {
1520 if (tchunk->tsn_gap_acked) {
1521 SCTP_DEBUG_PRINTK("%s: Receiver reneged on "
1522 "data TSN: 0x%x\n",
1523 __func__,
1524 tsn);
1525 tchunk->tsn_gap_acked = 0;
1526
1527 if (tchunk->transport)
1528 bytes_acked -= sctp_data_size(tchunk);
1529
1530 /* RFC 2960 6.3.2 Retransmission Timer Rules
1531 *
1532 * R4) Whenever a SACK is received missing a
1533 * TSN that was previously acknowledged via a
1534 * Gap Ack Block, start T3-rtx for the
1535 * destination address to which the DATA
1536 * chunk was originally
1537 * transmitted if it is not already running.
1538 */
1539 restart_timer = 1;
1540 }
1541
1542 list_add_tail(lchunk, &tlist);
1543
1544#if SCTP_DEBUG
1545 /* See the above comments on ACK-ed TSNs. */
1546 switch (dbg_prt_state) {
1547 case 1:
1548 if (dbg_last_kept_tsn + 1 == tsn)
1549 break;
1550
1551 if (dbg_last_kept_tsn != dbg_kept_tsn)
1552 SCTP_DEBUG_PRINTK_CONT("-%08x",
1553 dbg_last_kept_tsn);
1554
1555 SCTP_DEBUG_PRINTK_CONT(",%08x", tsn);
1556 dbg_kept_tsn = tsn;
1557 break;
1558
1559 case 0:
1560 if (dbg_last_ack_tsn != dbg_ack_tsn)
1561 SCTP_DEBUG_PRINTK_CONT("-%08x",
1562 dbg_last_ack_tsn);
1563 SCTP_DEBUG_PRINTK_CONT("\n");
1564
1565 /* FALL THROUGH... */
1566 default:
1567 SCTP_DEBUG_PRINTK("KEPT: %08x",tsn);
1568 dbg_prt_state = 1;
1569 dbg_kept_tsn = tsn;
1570 }
1571
1572 dbg_last_kept_tsn = tsn;
1573#endif /* SCTP_DEBUG */
1574 }
1575 }
1576
1577#if SCTP_DEBUG
1578 /* Finish off the last range, displaying its ending TSN. */
1579 switch (dbg_prt_state) {
1580 case 0:
1581 if (dbg_last_ack_tsn != dbg_ack_tsn) {
1582 SCTP_DEBUG_PRINTK_CONT("-%08x\n", dbg_last_ack_tsn);
1583 } else {
1584 SCTP_DEBUG_PRINTK_CONT("\n");
1585 }
1586 break;
1587
1588 case 1:
1589 if (dbg_last_kept_tsn != dbg_kept_tsn) {
1590 SCTP_DEBUG_PRINTK_CONT("-%08x\n", dbg_last_kept_tsn);
1591 } else {
1592 SCTP_DEBUG_PRINTK_CONT("\n");
1593 }
1594 }
1595#endif /* SCTP_DEBUG */
1596 if (transport) {
1597 if (bytes_acked) {
1598 struct sctp_association *asoc = transport->asoc;
1599
1600 /* We may have counted DATA that was migrated
1601 * to this transport due to DEL-IP operation.
1602 * Subtract those bytes, since the were never
1603 * send on this transport and shouldn't be
1604 * credited to this transport.
1605 */
1606 bytes_acked -= migrate_bytes;
1607
1608 /* 8.2. When an outstanding TSN is acknowledged,
1609 * the endpoint shall clear the error counter of
1610 * the destination transport address to which the
1611 * DATA chunk was last sent.
1612 * The association's overall error counter is
1613 * also cleared.
1614 */
1615 transport->error_count = 0;
1616 transport->asoc->overall_error_count = 0;
1617
1618 /*
1619 * While in SHUTDOWN PENDING, we may have started
1620 * the T5 shutdown guard timer after reaching the
1621 * retransmission limit. Stop that timer as soon
1622 * as the receiver acknowledged any data.
1623 */
1624 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING &&
1625 del_timer(&asoc->timers
1626 [SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD]))
1627 sctp_association_put(asoc);
1628
1629 /* Mark the destination transport address as
1630 * active if it is not so marked.
1631 */
1632 if ((transport->state == SCTP_INACTIVE) ||
1633 (transport->state == SCTP_UNCONFIRMED)) {
1634 sctp_assoc_control_transport(
1635 transport->asoc,
1636 transport,
1637 SCTP_TRANSPORT_UP,
1638 SCTP_RECEIVED_SACK);
1639 }
1640
1641 sctp_transport_raise_cwnd(transport, sack_ctsn,
1642 bytes_acked);
1643
1644 transport->flight_size -= bytes_acked;
1645 if (transport->flight_size == 0)
1646 transport->partial_bytes_acked = 0;
1647 q->outstanding_bytes -= bytes_acked + migrate_bytes;
1648 } else {
1649 /* RFC 2960 6.1, sctpimpguide-06 2.15.2
1650 * When a sender is doing zero window probing, it
1651 * should not timeout the association if it continues
1652 * to receive new packets from the receiver. The
1653 * reason is that the receiver MAY keep its window
1654 * closed for an indefinite time.
1655 * A sender is doing zero window probing when the
1656 * receiver's advertised window is zero, and there is
1657 * only one data chunk in flight to the receiver.
1658 *
1659 * Allow the association to timeout while in SHUTDOWN
1660 * PENDING or SHUTDOWN RECEIVED in case the receiver
1661 * stays in zero window mode forever.
1662 */
1663 if (!q->asoc->peer.rwnd &&
1664 !list_empty(&tlist) &&
1665 (sack_ctsn+2 == q->asoc->next_tsn) &&
1666 q->asoc->state < SCTP_STATE_SHUTDOWN_PENDING) {
1667 SCTP_DEBUG_PRINTK("%s: SACK received for zero "
1668 "window probe: %u\n",
1669 __func__, sack_ctsn);
1670 q->asoc->overall_error_count = 0;
1671 transport->error_count = 0;
1672 }
1673 }
1674
1675 /* RFC 2960 6.3.2 Retransmission Timer Rules
1676 *
1677 * R2) Whenever all outstanding data sent to an address have
1678 * been acknowledged, turn off the T3-rtx timer of that
1679 * address.
1680 */
1681 if (!transport->flight_size) {
1682 if (timer_pending(&transport->T3_rtx_timer) &&
1683 del_timer(&transport->T3_rtx_timer)) {
1684 sctp_transport_put(transport);
1685 }
1686 } else if (restart_timer) {
1687 if (!mod_timer(&transport->T3_rtx_timer,
1688 jiffies + transport->rto))
1689 sctp_transport_hold(transport);
1690 }
1691 }
1692
1693 list_splice(&tlist, transmitted_queue);
1694}
1695
1696/* Mark chunks as missing and consequently may get retransmitted. */
1697static void sctp_mark_missing(struct sctp_outq *q,
1698 struct list_head *transmitted_queue,
1699 struct sctp_transport *transport,
1700 __u32 highest_new_tsn_in_sack,
1701 int count_of_newacks)
1702{
1703 struct sctp_chunk *chunk;
1704 __u32 tsn;
1705 char do_fast_retransmit = 0;
1706 struct sctp_association *asoc = q->asoc;
1707 struct sctp_transport *primary = asoc->peer.primary_path;
1708
1709 list_for_each_entry(chunk, transmitted_queue, transmitted_list) {
1710
1711 tsn = ntohl(chunk->subh.data_hdr->tsn);
1712
1713 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all
1714 * 'Unacknowledged TSN's', if the TSN number of an
1715 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack'
1716 * value, increment the 'TSN.Missing.Report' count on that
1717 * chunk if it has NOT been fast retransmitted or marked for
1718 * fast retransmit already.
1719 */
1720 if (chunk->fast_retransmit == SCTP_CAN_FRTX &&
1721 !chunk->tsn_gap_acked &&
1722 TSN_lt(tsn, highest_new_tsn_in_sack)) {
1723
1724 /* SFR-CACC may require us to skip marking
1725 * this chunk as missing.
1726 */
1727 if (!transport || !sctp_cacc_skip(primary,
1728 chunk->transport,
1729 count_of_newacks, tsn)) {
1730 chunk->tsn_missing_report++;
1731
1732 SCTP_DEBUG_PRINTK(
1733 "%s: TSN 0x%x missing counter: %d\n",
1734 __func__, tsn,
1735 chunk->tsn_missing_report);
1736 }
1737 }
1738 /*
1739 * M4) If any DATA chunk is found to have a
1740 * 'TSN.Missing.Report'
1741 * value larger than or equal to 3, mark that chunk for
1742 * retransmission and start the fast retransmit procedure.
1743 */
1744
1745 if (chunk->tsn_missing_report >= 3) {
1746 chunk->fast_retransmit = SCTP_NEED_FRTX;
1747 do_fast_retransmit = 1;
1748 }
1749 }
1750
1751 if (transport) {
1752 if (do_fast_retransmit)
1753 sctp_retransmit(q, transport, SCTP_RTXR_FAST_RTX);
1754
1755 SCTP_DEBUG_PRINTK("%s: transport: %p, cwnd: %d, "
1756 "ssthresh: %d, flight_size: %d, pba: %d\n",
1757 __func__, transport, transport->cwnd,
1758 transport->ssthresh, transport->flight_size,
1759 transport->partial_bytes_acked);
1760 }
1761}
1762
1763/* Is the given TSN acked by this packet? */
1764static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn)
1765{
1766 int i;
1767 sctp_sack_variable_t *frags;
1768 __u16 gap;
1769 __u32 ctsn = ntohl(sack->cum_tsn_ack);
1770
1771 if (TSN_lte(tsn, ctsn))
1772 goto pass;
1773
1774 /* 3.3.4 Selective Acknowledgement (SACK) (3):
1775 *
1776 * Gap Ack Blocks:
1777 * These fields contain the Gap Ack Blocks. They are repeated
1778 * for each Gap Ack Block up to the number of Gap Ack Blocks
1779 * defined in the Number of Gap Ack Blocks field. All DATA
1780 * chunks with TSNs greater than or equal to (Cumulative TSN
1781 * Ack + Gap Ack Block Start) and less than or equal to
1782 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack
1783 * Block are assumed to have been received correctly.
1784 */
1785
1786 frags = sack->variable;
1787 gap = tsn - ctsn;
1788 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); ++i) {
1789 if (TSN_lte(ntohs(frags[i].gab.start), gap) &&
1790 TSN_lte(gap, ntohs(frags[i].gab.end)))
1791 goto pass;
1792 }
1793
1794 return 0;
1795pass:
1796 return 1;
1797}
1798
1799static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip *skiplist,
1800 int nskips, __be16 stream)
1801{
1802 int i;
1803
1804 for (i = 0; i < nskips; i++) {
1805 if (skiplist[i].stream == stream)
1806 return i;
1807 }
1808 return i;
1809}
1810
1811/* Create and add a fwdtsn chunk to the outq's control queue if needed. */
1812static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 ctsn)
1813{
1814 struct sctp_association *asoc = q->asoc;
1815 struct sctp_chunk *ftsn_chunk = NULL;
1816 struct sctp_fwdtsn_skip ftsn_skip_arr[10];
1817 int nskips = 0;
1818 int skip_pos = 0;
1819 __u32 tsn;
1820 struct sctp_chunk *chunk;
1821 struct list_head *lchunk, *temp;
1822
1823 if (!asoc->peer.prsctp_capable)
1824 return;
1825
1826 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the
1827 * received SACK.
1828 *
1829 * If (Advanced.Peer.Ack.Point < SackCumAck), then update
1830 * Advanced.Peer.Ack.Point to be equal to SackCumAck.
1831 */
1832 if (TSN_lt(asoc->adv_peer_ack_point, ctsn))
1833 asoc->adv_peer_ack_point = ctsn;
1834
1835 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point"
1836 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as
1837 * the chunk next in the out-queue space is marked as "abandoned" as
1838 * shown in the following example:
1839 *
1840 * Assuming that a SACK arrived with the Cumulative TSN ACK 102
1841 * and the Advanced.Peer.Ack.Point is updated to this value:
1842 *
1843 * out-queue at the end of ==> out-queue after Adv.Ack.Point
1844 * normal SACK processing local advancement
1845 * ... ...
1846 * Adv.Ack.Pt-> 102 acked 102 acked
1847 * 103 abandoned 103 abandoned
1848 * 104 abandoned Adv.Ack.P-> 104 abandoned
1849 * 105 105
1850 * 106 acked 106 acked
1851 * ... ...
1852 *
1853 * In this example, the data sender successfully advanced the
1854 * "Advanced.Peer.Ack.Point" from 102 to 104 locally.
1855 */
1856 list_for_each_safe(lchunk, temp, &q->abandoned) {
1857 chunk = list_entry(lchunk, struct sctp_chunk,
1858 transmitted_list);
1859 tsn = ntohl(chunk->subh.data_hdr->tsn);
1860
1861 /* Remove any chunks in the abandoned queue that are acked by
1862 * the ctsn.
1863 */
1864 if (TSN_lte(tsn, ctsn)) {
1865 list_del_init(lchunk);
1866 sctp_chunk_free(chunk);
1867 } else {
1868 if (TSN_lte(tsn, asoc->adv_peer_ack_point+1)) {
1869 asoc->adv_peer_ack_point = tsn;
1870 if (chunk->chunk_hdr->flags &
1871 SCTP_DATA_UNORDERED)
1872 continue;
1873 skip_pos = sctp_get_skip_pos(&ftsn_skip_arr[0],
1874 nskips,
1875 chunk->subh.data_hdr->stream);
1876 ftsn_skip_arr[skip_pos].stream =
1877 chunk->subh.data_hdr->stream;
1878 ftsn_skip_arr[skip_pos].ssn =
1879 chunk->subh.data_hdr->ssn;
1880 if (skip_pos == nskips)
1881 nskips++;
1882 if (nskips == 10)
1883 break;
1884 } else
1885 break;
1886 }
1887 }
1888
1889 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point"
1890 * is greater than the Cumulative TSN ACK carried in the received
1891 * SACK, the data sender MUST send the data receiver a FORWARD TSN
1892 * chunk containing the latest value of the
1893 * "Advanced.Peer.Ack.Point".
1894 *
1895 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD
1896 * list each stream and sequence number in the forwarded TSN. This
1897 * information will enable the receiver to easily find any
1898 * stranded TSN's waiting on stream reorder queues. Each stream
1899 * SHOULD only be reported once; this means that if multiple
1900 * abandoned messages occur in the same stream then only the
1901 * highest abandoned stream sequence number is reported. If the
1902 * total size of the FORWARD TSN does NOT fit in a single MTU then
1903 * the sender of the FORWARD TSN SHOULD lower the
1904 * Advanced.Peer.Ack.Point to the last TSN that will fit in a
1905 * single MTU.
1906 */
1907 if (asoc->adv_peer_ack_point > ctsn)
1908 ftsn_chunk = sctp_make_fwdtsn(asoc, asoc->adv_peer_ack_point,
1909 nskips, &ftsn_skip_arr[0]);
1910
1911 if (ftsn_chunk) {
1912 list_add_tail(&ftsn_chunk->list, &q->control_chunk_list);
1913 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
1914 }
1915}
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 = (union sctp_sack_variable *)(sack + 1);
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 __u32 sack_ctsn, ctsn, tsn;
1256 __u32 highest_tsn, highest_new_tsn;
1257 __u32 sack_a_rwnd;
1258 unsigned int outstanding;
1259 struct sctp_transport *primary = asoc->peer.primary_path;
1260 int count_of_newacks = 0;
1261 int gap_ack_blocks;
1262 u8 accum_moved = 0;
1263
1264 /* Grab the association's destination address list. */
1265 transport_list = &asoc->peer.transport_addr_list;
1266
1267 /* SCTP path tracepoint for congestion control debugging. */
1268 if (trace_sctp_probe_path_enabled()) {
1269 list_for_each_entry(transport, transport_list, transports)
1270 trace_sctp_probe_path(transport, asoc);
1271 }
1272
1273 sack_ctsn = ntohl(sack->cum_tsn_ack);
1274 gap_ack_blocks = ntohs(sack->num_gap_ack_blocks);
1275 asoc->stats.gapcnt += gap_ack_blocks;
1276 /*
1277 * SFR-CACC algorithm:
1278 * On receipt of a SACK the sender SHOULD execute the
1279 * following statements.
1280 *
1281 * 1) If the cumulative ack in the SACK passes next tsn_at_change
1282 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be
1283 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for
1284 * all destinations.
1285 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE
1286 * is set the receiver of the SACK MUST take the following actions:
1287 *
1288 * A) Initialize the cacc_saw_newack to 0 for all destination
1289 * addresses.
1290 *
1291 * Only bother if changeover_active is set. Otherwise, this is
1292 * totally suboptimal to do on every SACK.
1293 */
1294 if (primary->cacc.changeover_active) {
1295 u8 clear_cycling = 0;
1296
1297 if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) {
1298 primary->cacc.changeover_active = 0;
1299 clear_cycling = 1;
1300 }
1301
1302 if (clear_cycling || gap_ack_blocks) {
1303 list_for_each_entry(transport, transport_list,
1304 transports) {
1305 if (clear_cycling)
1306 transport->cacc.cycling_changeover = 0;
1307 if (gap_ack_blocks)
1308 transport->cacc.cacc_saw_newack = 0;
1309 }
1310 }
1311 }
1312
1313 /* Get the highest TSN in the sack. */
1314 highest_tsn = sack_ctsn;
1315 if (gap_ack_blocks) {
1316 union sctp_sack_variable *frags =
1317 (union sctp_sack_variable *)(sack + 1);
1318
1319 highest_tsn += ntohs(frags[gap_ack_blocks - 1].gab.end);
1320 }
1321
1322 if (TSN_lt(asoc->highest_sacked, highest_tsn))
1323 asoc->highest_sacked = highest_tsn;
1324
1325 highest_new_tsn = sack_ctsn;
1326
1327 /* Run through the retransmit queue. Credit bytes received
1328 * and free those chunks that we can.
1329 */
1330 sctp_check_transmitted(q, &q->retransmit, NULL, NULL, sack, &highest_new_tsn);
1331
1332 /* Run through the transmitted queue.
1333 * Credit bytes received and free those chunks which we can.
1334 *
1335 * This is a MASSIVE candidate for optimization.
1336 */
1337 list_for_each_entry(transport, transport_list, transports) {
1338 sctp_check_transmitted(q, &transport->transmitted,
1339 transport, &chunk->source, sack,
1340 &highest_new_tsn);
1341 /*
1342 * SFR-CACC algorithm:
1343 * C) Let count_of_newacks be the number of
1344 * destinations for which cacc_saw_newack is set.
1345 */
1346 if (transport->cacc.cacc_saw_newack)
1347 count_of_newacks++;
1348 }
1349
1350 /* Move the Cumulative TSN Ack Point if appropriate. */
1351 if (TSN_lt(asoc->ctsn_ack_point, sack_ctsn)) {
1352 asoc->ctsn_ack_point = sack_ctsn;
1353 accum_moved = 1;
1354 }
1355
1356 if (gap_ack_blocks) {
1357
1358 if (asoc->fast_recovery && accum_moved)
1359 highest_new_tsn = highest_tsn;
1360
1361 list_for_each_entry(transport, transport_list, transports)
1362 sctp_mark_missing(q, &transport->transmitted, transport,
1363 highest_new_tsn, count_of_newacks);
1364 }
1365
1366 /* Update unack_data field in the assoc. */
1367 sctp_sack_update_unack_data(asoc, sack);
1368
1369 ctsn = asoc->ctsn_ack_point;
1370
1371 /* Throw away stuff rotting on the sack queue. */
1372 list_for_each_safe(lchunk, temp, &q->sacked) {
1373 tchunk = list_entry(lchunk, struct sctp_chunk,
1374 transmitted_list);
1375 tsn = ntohl(tchunk->subh.data_hdr->tsn);
1376 if (TSN_lte(tsn, ctsn)) {
1377 list_del_init(&tchunk->transmitted_list);
1378 if (asoc->peer.prsctp_capable &&
1379 SCTP_PR_PRIO_ENABLED(chunk->sinfo.sinfo_flags))
1380 asoc->sent_cnt_removable--;
1381 sctp_chunk_free(tchunk);
1382 }
1383 }
1384
1385 /* ii) Set rwnd equal to the newly received a_rwnd minus the
1386 * number of bytes still outstanding after processing the
1387 * Cumulative TSN Ack and the Gap Ack Blocks.
1388 */
1389
1390 sack_a_rwnd = ntohl(sack->a_rwnd);
1391 asoc->peer.zero_window_announced = !sack_a_rwnd;
1392 outstanding = q->outstanding_bytes;
1393
1394 if (outstanding < sack_a_rwnd)
1395 sack_a_rwnd -= outstanding;
1396 else
1397 sack_a_rwnd = 0;
1398
1399 asoc->peer.rwnd = sack_a_rwnd;
1400
1401 asoc->stream.si->generate_ftsn(q, sack_ctsn);
1402
1403 pr_debug("%s: sack cumulative tsn ack:0x%x\n", __func__, sack_ctsn);
1404 pr_debug("%s: cumulative tsn ack of assoc:%p is 0x%x, "
1405 "advertised peer ack point:0x%x\n", __func__, asoc, ctsn,
1406 asoc->adv_peer_ack_point);
1407
1408 return sctp_outq_is_empty(q);
1409}
1410
1411/* Is the outqueue empty?
1412 * The queue is empty when we have not pending data, no in-flight data
1413 * and nothing pending retransmissions.
1414 */
1415int sctp_outq_is_empty(const struct sctp_outq *q)
1416{
1417 return q->out_qlen == 0 && q->outstanding_bytes == 0 &&
1418 list_empty(&q->retransmit);
1419}
1420
1421/********************************************************************
1422 * 2nd Level Abstractions
1423 ********************************************************************/
1424
1425/* Go through a transport's transmitted list or the association's retransmit
1426 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked.
1427 * The retransmit list will not have an associated transport.
1428 *
1429 * I added coherent debug information output. --xguo
1430 *
1431 * Instead of printing 'sacked' or 'kept' for each TSN on the
1432 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5.
1433 * KEPT TSN6-TSN7, etc.
1434 */
1435static void sctp_check_transmitted(struct sctp_outq *q,
1436 struct list_head *transmitted_queue,
1437 struct sctp_transport *transport,
1438 union sctp_addr *saddr,
1439 struct sctp_sackhdr *sack,
1440 __u32 *highest_new_tsn_in_sack)
1441{
1442 struct list_head *lchunk;
1443 struct sctp_chunk *tchunk;
1444 struct list_head tlist;
1445 __u32 tsn;
1446 __u32 sack_ctsn;
1447 __u32 rtt;
1448 __u8 restart_timer = 0;
1449 int bytes_acked = 0;
1450 int migrate_bytes = 0;
1451 bool forward_progress = false;
1452
1453 sack_ctsn = ntohl(sack->cum_tsn_ack);
1454
1455 INIT_LIST_HEAD(&tlist);
1456
1457 /* The while loop will skip empty transmitted queues. */
1458 while (NULL != (lchunk = sctp_list_dequeue(transmitted_queue))) {
1459 tchunk = list_entry(lchunk, struct sctp_chunk,
1460 transmitted_list);
1461
1462 if (sctp_chunk_abandoned(tchunk)) {
1463 /* Move the chunk to abandoned list. */
1464 sctp_insert_list(&q->abandoned, lchunk);
1465
1466 /* If this chunk has not been acked, stop
1467 * considering it as 'outstanding'.
1468 */
1469 if (transmitted_queue != &q->retransmit &&
1470 !tchunk->tsn_gap_acked) {
1471 if (tchunk->transport)
1472 tchunk->transport->flight_size -=
1473 sctp_data_size(tchunk);
1474 q->outstanding_bytes -= sctp_data_size(tchunk);
1475 }
1476 continue;
1477 }
1478
1479 tsn = ntohl(tchunk->subh.data_hdr->tsn);
1480 if (sctp_acked(sack, tsn)) {
1481 /* If this queue is the retransmit queue, the
1482 * retransmit timer has already reclaimed
1483 * the outstanding bytes for this chunk, so only
1484 * count bytes associated with a transport.
1485 */
1486 if (transport && !tchunk->tsn_gap_acked) {
1487 /* If this chunk is being used for RTT
1488 * measurement, calculate the RTT and update
1489 * the RTO using this value.
1490 *
1491 * 6.3.1 C5) Karn's algorithm: RTT measurements
1492 * MUST NOT be made using packets that were
1493 * retransmitted (and thus for which it is
1494 * ambiguous whether the reply was for the
1495 * first instance of the packet or a later
1496 * instance).
1497 */
1498 if (!sctp_chunk_retransmitted(tchunk) &&
1499 tchunk->rtt_in_progress) {
1500 tchunk->rtt_in_progress = 0;
1501 rtt = jiffies - tchunk->sent_at;
1502 sctp_transport_update_rto(transport,
1503 rtt);
1504 }
1505
1506 if (TSN_lte(tsn, sack_ctsn)) {
1507 /*
1508 * SFR-CACC algorithm:
1509 * 2) If the SACK contains gap acks
1510 * and the flag CHANGEOVER_ACTIVE is
1511 * set the receiver of the SACK MUST
1512 * take the following action:
1513 *
1514 * B) For each TSN t being acked that
1515 * has not been acked in any SACK so
1516 * far, set cacc_saw_newack to 1 for
1517 * the destination that the TSN was
1518 * sent to.
1519 */
1520 if (sack->num_gap_ack_blocks &&
1521 q->asoc->peer.primary_path->cacc.
1522 changeover_active)
1523 transport->cacc.cacc_saw_newack
1524 = 1;
1525 }
1526 }
1527
1528 /* If the chunk hasn't been marked as ACKED,
1529 * mark it and account bytes_acked if the
1530 * chunk had a valid transport (it will not
1531 * have a transport if ASCONF had deleted it
1532 * while DATA was outstanding).
1533 */
1534 if (!tchunk->tsn_gap_acked) {
1535 tchunk->tsn_gap_acked = 1;
1536 if (TSN_lt(*highest_new_tsn_in_sack, tsn))
1537 *highest_new_tsn_in_sack = tsn;
1538 bytes_acked += sctp_data_size(tchunk);
1539 if (!tchunk->transport)
1540 migrate_bytes += sctp_data_size(tchunk);
1541 forward_progress = true;
1542 }
1543
1544 if (TSN_lte(tsn, sack_ctsn)) {
1545 /* RFC 2960 6.3.2 Retransmission Timer Rules
1546 *
1547 * R3) Whenever a SACK is received
1548 * that acknowledges the DATA chunk
1549 * with the earliest outstanding TSN
1550 * for that address, restart T3-rtx
1551 * timer for that address with its
1552 * current RTO.
1553 */
1554 restart_timer = 1;
1555 forward_progress = true;
1556
1557 list_add_tail(&tchunk->transmitted_list,
1558 &q->sacked);
1559 } else {
1560 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2
1561 * M2) Each time a SACK arrives reporting
1562 * 'Stray DATA chunk(s)' record the highest TSN
1563 * reported as newly acknowledged, call this
1564 * value 'HighestTSNinSack'. A newly
1565 * acknowledged DATA chunk is one not
1566 * previously acknowledged in a SACK.
1567 *
1568 * When the SCTP sender of data receives a SACK
1569 * chunk that acknowledges, for the first time,
1570 * the receipt of a DATA chunk, all the still
1571 * unacknowledged DATA chunks whose TSN is
1572 * older than that newly acknowledged DATA
1573 * chunk, are qualified as 'Stray DATA chunks'.
1574 */
1575 list_add_tail(lchunk, &tlist);
1576 }
1577 } else {
1578 if (tchunk->tsn_gap_acked) {
1579 pr_debug("%s: receiver reneged on data TSN:0x%x\n",
1580 __func__, tsn);
1581
1582 tchunk->tsn_gap_acked = 0;
1583
1584 if (tchunk->transport)
1585 bytes_acked -= sctp_data_size(tchunk);
1586
1587 /* RFC 2960 6.3.2 Retransmission Timer Rules
1588 *
1589 * R4) Whenever a SACK is received missing a
1590 * TSN that was previously acknowledged via a
1591 * Gap Ack Block, start T3-rtx for the
1592 * destination address to which the DATA
1593 * chunk was originally
1594 * transmitted if it is not already running.
1595 */
1596 restart_timer = 1;
1597 }
1598
1599 list_add_tail(lchunk, &tlist);
1600 }
1601 }
1602
1603 if (transport) {
1604 if (bytes_acked) {
1605 struct sctp_association *asoc = transport->asoc;
1606
1607 /* We may have counted DATA that was migrated
1608 * to this transport due to DEL-IP operation.
1609 * Subtract those bytes, since the were never
1610 * send on this transport and shouldn't be
1611 * credited to this transport.
1612 */
1613 bytes_acked -= migrate_bytes;
1614
1615 /* 8.2. When an outstanding TSN is acknowledged,
1616 * the endpoint shall clear the error counter of
1617 * the destination transport address to which the
1618 * DATA chunk was last sent.
1619 * The association's overall error counter is
1620 * also cleared.
1621 */
1622 transport->error_count = 0;
1623 transport->asoc->overall_error_count = 0;
1624 forward_progress = true;
1625
1626 /*
1627 * While in SHUTDOWN PENDING, we may have started
1628 * the T5 shutdown guard timer after reaching the
1629 * retransmission limit. Stop that timer as soon
1630 * as the receiver acknowledged any data.
1631 */
1632 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING &&
1633 del_timer(&asoc->timers
1634 [SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD]))
1635 sctp_association_put(asoc);
1636
1637 /* Mark the destination transport address as
1638 * active if it is not so marked.
1639 */
1640 if ((transport->state == SCTP_INACTIVE ||
1641 transport->state == SCTP_UNCONFIRMED) &&
1642 sctp_cmp_addr_exact(&transport->ipaddr, saddr)) {
1643 sctp_assoc_control_transport(
1644 transport->asoc,
1645 transport,
1646 SCTP_TRANSPORT_UP,
1647 SCTP_RECEIVED_SACK);
1648 }
1649
1650 sctp_transport_raise_cwnd(transport, sack_ctsn,
1651 bytes_acked);
1652
1653 transport->flight_size -= bytes_acked;
1654 if (transport->flight_size == 0)
1655 transport->partial_bytes_acked = 0;
1656 q->outstanding_bytes -= bytes_acked + migrate_bytes;
1657 } else {
1658 /* RFC 2960 6.1, sctpimpguide-06 2.15.2
1659 * When a sender is doing zero window probing, it
1660 * should not timeout the association if it continues
1661 * to receive new packets from the receiver. The
1662 * reason is that the receiver MAY keep its window
1663 * closed for an indefinite time.
1664 * A sender is doing zero window probing when the
1665 * receiver's advertised window is zero, and there is
1666 * only one data chunk in flight to the receiver.
1667 *
1668 * Allow the association to timeout while in SHUTDOWN
1669 * PENDING or SHUTDOWN RECEIVED in case the receiver
1670 * stays in zero window mode forever.
1671 */
1672 if (!q->asoc->peer.rwnd &&
1673 !list_empty(&tlist) &&
1674 (sack_ctsn+2 == q->asoc->next_tsn) &&
1675 q->asoc->state < SCTP_STATE_SHUTDOWN_PENDING) {
1676 pr_debug("%s: sack received for zero window "
1677 "probe:%u\n", __func__, sack_ctsn);
1678
1679 q->asoc->overall_error_count = 0;
1680 transport->error_count = 0;
1681 }
1682 }
1683
1684 /* RFC 2960 6.3.2 Retransmission Timer Rules
1685 *
1686 * R2) Whenever all outstanding data sent to an address have
1687 * been acknowledged, turn off the T3-rtx timer of that
1688 * address.
1689 */
1690 if (!transport->flight_size) {
1691 if (del_timer(&transport->T3_rtx_timer))
1692 sctp_transport_put(transport);
1693 } else if (restart_timer) {
1694 if (!mod_timer(&transport->T3_rtx_timer,
1695 jiffies + transport->rto))
1696 sctp_transport_hold(transport);
1697 }
1698
1699 if (forward_progress) {
1700 if (transport->dst)
1701 sctp_transport_dst_confirm(transport);
1702 }
1703 }
1704
1705 list_splice(&tlist, transmitted_queue);
1706}
1707
1708/* Mark chunks as missing and consequently may get retransmitted. */
1709static void sctp_mark_missing(struct sctp_outq *q,
1710 struct list_head *transmitted_queue,
1711 struct sctp_transport *transport,
1712 __u32 highest_new_tsn_in_sack,
1713 int count_of_newacks)
1714{
1715 struct sctp_chunk *chunk;
1716 __u32 tsn;
1717 char do_fast_retransmit = 0;
1718 struct sctp_association *asoc = q->asoc;
1719 struct sctp_transport *primary = asoc->peer.primary_path;
1720
1721 list_for_each_entry(chunk, transmitted_queue, transmitted_list) {
1722
1723 tsn = ntohl(chunk->subh.data_hdr->tsn);
1724
1725 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all
1726 * 'Unacknowledged TSN's', if the TSN number of an
1727 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack'
1728 * value, increment the 'TSN.Missing.Report' count on that
1729 * chunk if it has NOT been fast retransmitted or marked for
1730 * fast retransmit already.
1731 */
1732 if (chunk->fast_retransmit == SCTP_CAN_FRTX &&
1733 !chunk->tsn_gap_acked &&
1734 TSN_lt(tsn, highest_new_tsn_in_sack)) {
1735
1736 /* SFR-CACC may require us to skip marking
1737 * this chunk as missing.
1738 */
1739 if (!transport || !sctp_cacc_skip(primary,
1740 chunk->transport,
1741 count_of_newacks, tsn)) {
1742 chunk->tsn_missing_report++;
1743
1744 pr_debug("%s: tsn:0x%x missing counter:%d\n",
1745 __func__, tsn, chunk->tsn_missing_report);
1746 }
1747 }
1748 /*
1749 * M4) If any DATA chunk is found to have a
1750 * 'TSN.Missing.Report'
1751 * value larger than or equal to 3, mark that chunk for
1752 * retransmission and start the fast retransmit procedure.
1753 */
1754
1755 if (chunk->tsn_missing_report >= 3) {
1756 chunk->fast_retransmit = SCTP_NEED_FRTX;
1757 do_fast_retransmit = 1;
1758 }
1759 }
1760
1761 if (transport) {
1762 if (do_fast_retransmit)
1763 sctp_retransmit(q, transport, SCTP_RTXR_FAST_RTX);
1764
1765 pr_debug("%s: transport:%p, cwnd:%d, ssthresh:%d, "
1766 "flight_size:%d, pba:%d\n", __func__, transport,
1767 transport->cwnd, transport->ssthresh,
1768 transport->flight_size, transport->partial_bytes_acked);
1769 }
1770}
1771
1772/* Is the given TSN acked by this packet? */
1773static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn)
1774{
1775 __u32 ctsn = ntohl(sack->cum_tsn_ack);
1776 union sctp_sack_variable *frags;
1777 __u16 tsn_offset, blocks;
1778 int i;
1779
1780 if (TSN_lte(tsn, ctsn))
1781 goto pass;
1782
1783 /* 3.3.4 Selective Acknowledgment (SACK) (3):
1784 *
1785 * Gap Ack Blocks:
1786 * These fields contain the Gap Ack Blocks. They are repeated
1787 * for each Gap Ack Block up to the number of Gap Ack Blocks
1788 * defined in the Number of Gap Ack Blocks field. All DATA
1789 * chunks with TSNs greater than or equal to (Cumulative TSN
1790 * Ack + Gap Ack Block Start) and less than or equal to
1791 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack
1792 * Block are assumed to have been received correctly.
1793 */
1794
1795 frags = (union sctp_sack_variable *)(sack + 1);
1796 blocks = ntohs(sack->num_gap_ack_blocks);
1797 tsn_offset = tsn - ctsn;
1798 for (i = 0; i < blocks; ++i) {
1799 if (tsn_offset >= ntohs(frags[i].gab.start) &&
1800 tsn_offset <= ntohs(frags[i].gab.end))
1801 goto pass;
1802 }
1803
1804 return 0;
1805pass:
1806 return 1;
1807}
1808
1809static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip *skiplist,
1810 int nskips, __be16 stream)
1811{
1812 int i;
1813
1814 for (i = 0; i < nskips; i++) {
1815 if (skiplist[i].stream == stream)
1816 return i;
1817 }
1818 return i;
1819}
1820
1821/* Create and add a fwdtsn chunk to the outq's control queue if needed. */
1822void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 ctsn)
1823{
1824 struct sctp_association *asoc = q->asoc;
1825 struct sctp_chunk *ftsn_chunk = NULL;
1826 struct sctp_fwdtsn_skip ftsn_skip_arr[10];
1827 int nskips = 0;
1828 int skip_pos = 0;
1829 __u32 tsn;
1830 struct sctp_chunk *chunk;
1831 struct list_head *lchunk, *temp;
1832
1833 if (!asoc->peer.prsctp_capable)
1834 return;
1835
1836 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the
1837 * received SACK.
1838 *
1839 * If (Advanced.Peer.Ack.Point < SackCumAck), then update
1840 * Advanced.Peer.Ack.Point to be equal to SackCumAck.
1841 */
1842 if (TSN_lt(asoc->adv_peer_ack_point, ctsn))
1843 asoc->adv_peer_ack_point = ctsn;
1844
1845 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point"
1846 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as
1847 * the chunk next in the out-queue space is marked as "abandoned" as
1848 * shown in the following example:
1849 *
1850 * Assuming that a SACK arrived with the Cumulative TSN ACK 102
1851 * and the Advanced.Peer.Ack.Point is updated to this value:
1852 *
1853 * out-queue at the end of ==> out-queue after Adv.Ack.Point
1854 * normal SACK processing local advancement
1855 * ... ...
1856 * Adv.Ack.Pt-> 102 acked 102 acked
1857 * 103 abandoned 103 abandoned
1858 * 104 abandoned Adv.Ack.P-> 104 abandoned
1859 * 105 105
1860 * 106 acked 106 acked
1861 * ... ...
1862 *
1863 * In this example, the data sender successfully advanced the
1864 * "Advanced.Peer.Ack.Point" from 102 to 104 locally.
1865 */
1866 list_for_each_safe(lchunk, temp, &q->abandoned) {
1867 chunk = list_entry(lchunk, struct sctp_chunk,
1868 transmitted_list);
1869 tsn = ntohl(chunk->subh.data_hdr->tsn);
1870
1871 /* Remove any chunks in the abandoned queue that are acked by
1872 * the ctsn.
1873 */
1874 if (TSN_lte(tsn, ctsn)) {
1875 list_del_init(lchunk);
1876 sctp_chunk_free(chunk);
1877 } else {
1878 if (TSN_lte(tsn, asoc->adv_peer_ack_point+1)) {
1879 asoc->adv_peer_ack_point = tsn;
1880 if (chunk->chunk_hdr->flags &
1881 SCTP_DATA_UNORDERED)
1882 continue;
1883 skip_pos = sctp_get_skip_pos(&ftsn_skip_arr[0],
1884 nskips,
1885 chunk->subh.data_hdr->stream);
1886 ftsn_skip_arr[skip_pos].stream =
1887 chunk->subh.data_hdr->stream;
1888 ftsn_skip_arr[skip_pos].ssn =
1889 chunk->subh.data_hdr->ssn;
1890 if (skip_pos == nskips)
1891 nskips++;
1892 if (nskips == 10)
1893 break;
1894 } else
1895 break;
1896 }
1897 }
1898
1899 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point"
1900 * is greater than the Cumulative TSN ACK carried in the received
1901 * SACK, the data sender MUST send the data receiver a FORWARD TSN
1902 * chunk containing the latest value of the
1903 * "Advanced.Peer.Ack.Point".
1904 *
1905 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD
1906 * list each stream and sequence number in the forwarded TSN. This
1907 * information will enable the receiver to easily find any
1908 * stranded TSN's waiting on stream reorder queues. Each stream
1909 * SHOULD only be reported once; this means that if multiple
1910 * abandoned messages occur in the same stream then only the
1911 * highest abandoned stream sequence number is reported. If the
1912 * total size of the FORWARD TSN does NOT fit in a single MTU then
1913 * the sender of the FORWARD TSN SHOULD lower the
1914 * Advanced.Peer.Ack.Point to the last TSN that will fit in a
1915 * single MTU.
1916 */
1917 if (asoc->adv_peer_ack_point > ctsn)
1918 ftsn_chunk = sctp_make_fwdtsn(asoc, asoc->adv_peer_ack_point,
1919 nskips, &ftsn_skip_arr[0]);
1920
1921 if (ftsn_chunk) {
1922 list_add_tail(&ftsn_chunk->list, &q->control_chunk_list);
1923 SCTP_INC_STATS(asoc->base.net, SCTP_MIB_OUTCTRLCHUNKS);
1924 }
1925}