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