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