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