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