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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* SCTP kernel reference 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 reference Implementation
8 *
9 * These functions implement the sctp_outq class. The outqueue handles
10 * bundling and queueing of outgoing SCTP chunks.
11 *
12 * The SCTP reference 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 * The SCTP reference implementation is distributed in the hope that it
19 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
20 * ************************
21 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
22 * See the GNU General Public License for more details.
23 *
24 * You should have received a copy of the GNU General Public License
25 * along with GNU CC; see the file COPYING. If not, write to
26 * the Free Software Foundation, 59 Temple Place - Suite 330,
27 * Boston, MA 02111-1307, USA.
28 *
29 * Please send any bug reports or fixes you make to the
30 * email address(es):
31 * lksctp developers <lksctp-developers@lists.sourceforge.net>
32 *
33 * Or submit a bug report through the following website:
34 * http://www.sf.net/projects/lksctp
35 *
36 * Written or modified by:
37 * La Monte H.P. Yarroll <piggy@acm.org>
38 * Karl Knutson <karl@athena.chicago.il.us>
39 * Perry Melange <pmelange@null.cc.uic.edu>
40 * Xingang Guo <xingang.guo@intel.com>
41 * Hui Huang <hui.huang@nokia.com>
42 * Sridhar Samudrala <sri@us.ibm.com>
43 * Jon Grimm <jgrimm@us.ibm.com>
44 *
45 * Any bugs reported given to us we will try to fix... any fixes shared will
46 * be incorporated into the next SCTP release.
47 */
48
49#include <linux/types.h>
50#include <linux/list.h> /* For struct list_head */
51#include <linux/socket.h>
52#include <linux/ip.h>
53#include <net/sock.h> /* For skb_set_owner_w */
54
55#include <net/sctp/sctp.h>
56#include <net/sctp/sm.h>
57
58/* Declare internal functions here. */
59static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn);
60static void sctp_check_transmitted(struct sctp_outq *q,
61 struct list_head *transmitted_queue,
62 struct sctp_transport *transport,
63 struct sctp_sackhdr *sack,
64 __u32 highest_new_tsn);
65
66static void sctp_mark_missing(struct sctp_outq *q,
67 struct list_head *transmitted_queue,
68 struct sctp_transport *transport,
69 __u32 highest_new_tsn,
70 int count_of_newacks);
71
72static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 sack_ctsn);
73
74/* Add data to the front of the queue. */
75static inline void sctp_outq_head_data(struct sctp_outq *q,
76 struct sctp_chunk *ch)
77{
David S. Miller79af02c2005-07-08 21:47:49 -070078 list_add(&ch->list, &q->out_chunk_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -070079 q->out_qlen += ch->skb->len;
80 return;
81}
82
83/* Take data from the front of the queue. */
84static inline struct sctp_chunk *sctp_outq_dequeue_data(struct sctp_outq *q)
85{
David S. Miller79af02c2005-07-08 21:47:49 -070086 struct sctp_chunk *ch = NULL;
87
88 if (!list_empty(&q->out_chunk_list)) {
89 struct list_head *entry = q->out_chunk_list.next;
90
91 ch = list_entry(entry, struct sctp_chunk, list);
92 list_del_init(entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -070093 q->out_qlen -= ch->skb->len;
David S. Miller79af02c2005-07-08 21:47:49 -070094 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070095 return ch;
96}
97/* Add data chunk to the end of the queue. */
98static inline void sctp_outq_tail_data(struct sctp_outq *q,
99 struct sctp_chunk *ch)
100{
David S. Miller79af02c2005-07-08 21:47:49 -0700101 list_add_tail(&ch->list, &q->out_chunk_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102 q->out_qlen += ch->skb->len;
103 return;
104}
105
106/*
107 * SFR-CACC algorithm:
108 * D) If count_of_newacks is greater than or equal to 2
109 * and t was not sent to the current primary then the
110 * sender MUST NOT increment missing report count for t.
111 */
112static inline int sctp_cacc_skip_3_1_d(struct sctp_transport *primary,
113 struct sctp_transport *transport,
114 int count_of_newacks)
115{
116 if (count_of_newacks >=2 && transport != primary)
117 return 1;
118 return 0;
119}
120
121/*
122 * SFR-CACC algorithm:
123 * F) If count_of_newacks is less than 2, let d be the
124 * destination to which t was sent. If cacc_saw_newack
125 * is 0 for destination d, then the sender MUST NOT
126 * increment missing report count for t.
127 */
128static inline int sctp_cacc_skip_3_1_f(struct sctp_transport *transport,
129 int count_of_newacks)
130{
131 if (count_of_newacks < 2 && !transport->cacc.cacc_saw_newack)
132 return 1;
133 return 0;
134}
135
136/*
137 * SFR-CACC algorithm:
138 * 3.1) If CYCLING_CHANGEOVER is 0, the sender SHOULD
139 * execute steps C, D, F.
140 *
141 * C has been implemented in sctp_outq_sack
142 */
143static inline int sctp_cacc_skip_3_1(struct sctp_transport *primary,
144 struct sctp_transport *transport,
145 int count_of_newacks)
146{
147 if (!primary->cacc.cycling_changeover) {
148 if (sctp_cacc_skip_3_1_d(primary, transport, count_of_newacks))
149 return 1;
150 if (sctp_cacc_skip_3_1_f(transport, count_of_newacks))
151 return 1;
152 return 0;
153 }
154 return 0;
155}
156
157/*
158 * SFR-CACC algorithm:
159 * 3.2) Else if CYCLING_CHANGEOVER is 1, and t is less
160 * than next_tsn_at_change of the current primary, then
161 * the sender MUST NOT increment missing report count
162 * for t.
163 */
164static inline int sctp_cacc_skip_3_2(struct sctp_transport *primary, __u32 tsn)
165{
166 if (primary->cacc.cycling_changeover &&
167 TSN_lt(tsn, primary->cacc.next_tsn_at_change))
168 return 1;
169 return 0;
170}
171
172/*
173 * SFR-CACC algorithm:
174 * 3) If the missing report count for TSN t is to be
175 * incremented according to [RFC2960] and
176 * [SCTP_STEWART-2002], and CHANGEOVER_ACTIVE is set,
177 * then the sender MUST futher execute steps 3.1 and
178 * 3.2 to determine if the missing report count for
179 * TSN t SHOULD NOT be incremented.
180 *
181 * 3.3) If 3.1 and 3.2 do not dictate that the missing
182 * report count for t should not be incremented, then
183 * the sender SOULD increment missing report count for
184 * t (according to [RFC2960] and [SCTP_STEWART_2002]).
185 */
186static inline int sctp_cacc_skip(struct sctp_transport *primary,
187 struct sctp_transport *transport,
188 int count_of_newacks,
189 __u32 tsn)
190{
191 if (primary->cacc.changeover_active &&
192 (sctp_cacc_skip_3_1(primary, transport, count_of_newacks)
193 || sctp_cacc_skip_3_2(primary, tsn)))
194 return 1;
195 return 0;
196}
197
198/* Initialize an existing sctp_outq. This does the boring stuff.
199 * You still need to define handlers if you really want to DO
200 * something with this structure...
201 */
202void sctp_outq_init(struct sctp_association *asoc, struct sctp_outq *q)
203{
204 q->asoc = asoc;
David S. Miller79af02c2005-07-08 21:47:49 -0700205 INIT_LIST_HEAD(&q->out_chunk_list);
206 INIT_LIST_HEAD(&q->control_chunk_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700207 INIT_LIST_HEAD(&q->retransmit);
208 INIT_LIST_HEAD(&q->sacked);
209 INIT_LIST_HEAD(&q->abandoned);
210
211 q->outstanding_bytes = 0;
212 q->empty = 1;
213 q->cork = 0;
214
215 q->malloced = 0;
216 q->out_qlen = 0;
217}
218
219/* Free the outqueue structure and any related pending chunks.
220 */
221void sctp_outq_teardown(struct sctp_outq *q)
222{
223 struct sctp_transport *transport;
224 struct list_head *lchunk, *pos, *temp;
David S. Miller79af02c2005-07-08 21:47:49 -0700225 struct sctp_chunk *chunk, *tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226
227 /* Throw away unacknowledged chunks. */
228 list_for_each(pos, &q->asoc->peer.transport_addr_list) {
229 transport = list_entry(pos, struct sctp_transport, transports);
230 while ((lchunk = sctp_list_dequeue(&transport->transmitted)) != NULL) {
231 chunk = list_entry(lchunk, struct sctp_chunk,
232 transmitted_list);
233 /* Mark as part of a failed message. */
234 sctp_chunk_fail(chunk, q->error);
235 sctp_chunk_free(chunk);
236 }
237 }
238
239 /* Throw away chunks that have been gap ACKed. */
240 list_for_each_safe(lchunk, temp, &q->sacked) {
241 list_del_init(lchunk);
242 chunk = list_entry(lchunk, struct sctp_chunk,
243 transmitted_list);
244 sctp_chunk_fail(chunk, q->error);
245 sctp_chunk_free(chunk);
246 }
247
248 /* Throw away any chunks in the retransmit queue. */
249 list_for_each_safe(lchunk, temp, &q->retransmit) {
250 list_del_init(lchunk);
251 chunk = list_entry(lchunk, struct sctp_chunk,
252 transmitted_list);
253 sctp_chunk_fail(chunk, q->error);
254 sctp_chunk_free(chunk);
255 }
256
257 /* Throw away any chunks that are in the abandoned queue. */
258 list_for_each_safe(lchunk, temp, &q->abandoned) {
259 list_del_init(lchunk);
260 chunk = list_entry(lchunk, struct sctp_chunk,
261 transmitted_list);
262 sctp_chunk_fail(chunk, q->error);
263 sctp_chunk_free(chunk);
264 }
265
266 /* Throw away any leftover data chunks. */
267 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) {
268
269 /* Mark as send failure. */
270 sctp_chunk_fail(chunk, q->error);
271 sctp_chunk_free(chunk);
272 }
273
274 q->error = 0;
275
276 /* Throw away any leftover control chunks. */
David S. Miller79af02c2005-07-08 21:47:49 -0700277 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) {
278 list_del_init(&chunk->list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279 sctp_chunk_free(chunk);
David S. Miller79af02c2005-07-08 21:47:49 -0700280 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281}
282
283/* Free the outqueue structure and any related pending chunks. */
284void sctp_outq_free(struct sctp_outq *q)
285{
286 /* Throw away leftover chunks. */
287 sctp_outq_teardown(q);
288
289 /* If we were kmalloc()'d, free the memory. */
290 if (q->malloced)
291 kfree(q);
292}
293
294/* Put a new chunk in an sctp_outq. */
295int sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk)
296{
297 int error = 0;
298
299 SCTP_DEBUG_PRINTK("sctp_outq_tail(%p, %p[%s])\n",
300 q, chunk, 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_CID_DATA == chunk->chunk_hdr->type) {
308 /* Is it OK to queue data chunks? */
309 /* From 9. Termination of Association
310 *
311 * When either endpoint performs a shutdown, the
312 * association on each peer will stop accepting new
313 * data from its user and only deliver data in queue
314 * at the time of sending or receiving the SHUTDOWN
315 * chunk.
316 */
317 switch (q->asoc->state) {
318 case SCTP_STATE_EMPTY:
319 case SCTP_STATE_CLOSED:
320 case SCTP_STATE_SHUTDOWN_PENDING:
321 case SCTP_STATE_SHUTDOWN_SENT:
322 case SCTP_STATE_SHUTDOWN_RECEIVED:
323 case SCTP_STATE_SHUTDOWN_ACK_SENT:
324 /* Cannot send after transport endpoint shutdown */
325 error = -ESHUTDOWN;
326 break;
327
328 default:
329 SCTP_DEBUG_PRINTK("outqueueing (%p, %p[%s])\n",
330 q, chunk, chunk && chunk->chunk_hdr ?
331 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type))
332 : "Illegal Chunk");
333
334 sctp_outq_tail_data(q, chunk);
335 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED)
336 SCTP_INC_STATS(SCTP_MIB_OUTUNORDERCHUNKS);
337 else
338 SCTP_INC_STATS(SCTP_MIB_OUTORDERCHUNKS);
339 q->empty = 0;
340 break;
341 };
342 } else {
David S. Miller79af02c2005-07-08 21:47:49 -0700343 list_add_tail(&chunk->list, &q->control_chunk_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
345 }
346
347 if (error < 0)
348 return error;
349
350 if (!q->cork)
351 error = sctp_outq_flush(q, 0);
352
353 return error;
354}
355
356/* Insert a chunk into the sorted list based on the TSNs. The retransmit list
357 * and the abandoned list are in ascending order.
358 */
359static void sctp_insert_list(struct list_head *head, struct list_head *new)
360{
361 struct list_head *pos;
362 struct sctp_chunk *nchunk, *lchunk;
363 __u32 ntsn, ltsn;
364 int done = 0;
365
366 nchunk = list_entry(new, struct sctp_chunk, transmitted_list);
367 ntsn = ntohl(nchunk->subh.data_hdr->tsn);
368
369 list_for_each(pos, head) {
370 lchunk = list_entry(pos, struct sctp_chunk, transmitted_list);
371 ltsn = ntohl(lchunk->subh.data_hdr->tsn);
372 if (TSN_lt(ntsn, ltsn)) {
373 list_add(new, pos->prev);
374 done = 1;
375 break;
376 }
377 }
378 if (!done)
379 list_add_tail(new, head);
380}
381
382/* Mark all the eligible packets on a transport for retransmission. */
383void sctp_retransmit_mark(struct sctp_outq *q,
384 struct sctp_transport *transport,
385 __u8 fast_retransmit)
386{
387 struct list_head *lchunk, *ltemp;
388 struct sctp_chunk *chunk;
389
390 /* Walk through the specified transmitted queue. */
391 list_for_each_safe(lchunk, ltemp, &transport->transmitted) {
392 chunk = list_entry(lchunk, struct sctp_chunk,
393 transmitted_list);
394
395 /* If the chunk is abandoned, move it to abandoned list. */
396 if (sctp_chunk_abandoned(chunk)) {
397 list_del_init(lchunk);
398 sctp_insert_list(&q->abandoned, lchunk);
399 continue;
400 }
401
402 /* If we are doing retransmission due to a fast retransmit,
403 * only the chunk's that are marked for fast retransmit
404 * should be added to the retransmit queue. If we are doing
405 * retransmission due to a timeout or pmtu discovery, only the
406 * chunks that are not yet acked should be added to the
407 * retransmit queue.
408 */
Vlad Yasevich27852c22006-02-02 16:57:31 -0800409 if ((fast_retransmit && (chunk->fast_retransmit > 0)) ||
Linus Torvalds1da177e2005-04-16 15:20:36 -0700410 (!fast_retransmit && !chunk->tsn_gap_acked)) {
411 /* RFC 2960 6.2.1 Processing a Received SACK
412 *
413 * C) Any time a DATA chunk is marked for
414 * retransmission (via either T3-rtx timer expiration
415 * (Section 6.3.3) or via fast retransmit
416 * (Section 7.2.4)), add the data size of those
417 * chunks to the rwnd.
418 */
419 q->asoc->peer.rwnd += sctp_data_size(chunk);
420 q->outstanding_bytes -= sctp_data_size(chunk);
421 transport->flight_size -= sctp_data_size(chunk);
422
423 /* sctpimpguide-05 Section 2.8.2
424 * M5) If a T3-rtx timer expires, the
425 * 'TSN.Missing.Report' of all affected TSNs is set
426 * to 0.
427 */
428 chunk->tsn_missing_report = 0;
429
430 /* If a chunk that is being used for RTT measurement
431 * has to be retransmitted, we cannot use this chunk
432 * anymore for RTT measurements. Reset rto_pending so
433 * that a new RTT measurement is started when a new
434 * data chunk is sent.
435 */
436 if (chunk->rtt_in_progress) {
437 chunk->rtt_in_progress = 0;
438 transport->rto_pending = 0;
439 }
440
441 /* Move the chunk to the retransmit queue. The chunks
442 * on the retransmit queue are always kept in order.
443 */
444 list_del_init(lchunk);
445 sctp_insert_list(&q->retransmit, lchunk);
446 }
447 }
448
449 SCTP_DEBUG_PRINTK("%s: transport: %p, fast_retransmit: %d, "
450 "cwnd: %d, ssthresh: %d, flight_size: %d, "
451 "pba: %d\n", __FUNCTION__,
452 transport, fast_retransmit,
453 transport->cwnd, transport->ssthresh,
454 transport->flight_size,
455 transport->partial_bytes_acked);
456
457}
458
459/* Mark all the eligible packets on a transport for retransmission and force
460 * one packet out.
461 */
462void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
463 sctp_retransmit_reason_t reason)
464{
465 int error = 0;
466 __u8 fast_retransmit = 0;
467
468 switch(reason) {
469 case SCTP_RTXR_T3_RTX:
470 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_T3_RTX);
471 /* Update the retran path if the T3-rtx timer has expired for
472 * the current retran path.
473 */
474 if (transport == transport->asoc->peer.retran_path)
475 sctp_assoc_update_retran_path(transport->asoc);
476 break;
477 case SCTP_RTXR_FAST_RTX:
478 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_FAST_RTX);
479 fast_retransmit = 1;
480 break;
481 case SCTP_RTXR_PMTUD:
482 default:
483 break;
484 }
485
486 sctp_retransmit_mark(q, transport, fast_retransmit);
487
488 /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination,
489 * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by
490 * following the procedures outlined in C1 - C5.
491 */
492 sctp_generate_fwdtsn(q, q->asoc->ctsn_ack_point);
493
494 error = sctp_outq_flush(q, /* rtx_timeout */ 1);
495
496 if (error)
497 q->asoc->base.sk->sk_err = -error;
498}
499
500/*
501 * Transmit DATA chunks on the retransmit queue. Upon return from
502 * sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which
503 * need to be transmitted by the caller.
504 * We assume that pkt->transport has already been set.
505 *
506 * The return value is a normal kernel error return value.
507 */
508static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
509 int rtx_timeout, int *start_timer)
510{
511 struct list_head *lqueue;
512 struct list_head *lchunk, *lchunk1;
513 struct sctp_transport *transport = pkt->transport;
514 sctp_xmit_t status;
515 struct sctp_chunk *chunk, *chunk1;
516 struct sctp_association *asoc;
517 int error = 0;
518
519 asoc = q->asoc;
520 lqueue = &q->retransmit;
521
522 /* RFC 2960 6.3.3 Handle T3-rtx Expiration
523 *
524 * E3) Determine how many of the earliest (i.e., lowest TSN)
525 * outstanding DATA chunks for the address for which the
526 * T3-rtx has expired will fit into a single packet, subject
527 * to the MTU constraint for the path corresponding to the
528 * destination transport address to which the retransmission
529 * is being sent (this may be different from the address for
530 * which the timer expires [see Section 6.4]). Call this value
531 * K. Bundle and retransmit those K DATA chunks in a single
532 * packet to the destination endpoint.
533 *
534 * [Just to be painfully clear, if we are retransmitting
535 * because a timeout just happened, we should send only ONE
536 * packet of retransmitted data.]
537 */
538 lchunk = sctp_list_dequeue(lqueue);
539
540 while (lchunk) {
541 chunk = list_entry(lchunk, struct sctp_chunk,
542 transmitted_list);
543
544 /* Make sure that Gap Acked TSNs are not retransmitted. A
545 * simple approach is just to move such TSNs out of the
546 * way and into a 'transmitted' queue and skip to the
547 * next chunk.
548 */
549 if (chunk->tsn_gap_acked) {
550 list_add_tail(lchunk, &transport->transmitted);
551 lchunk = sctp_list_dequeue(lqueue);
552 continue;
553 }
554
555 /* Attempt to append this chunk to the packet. */
556 status = sctp_packet_append_chunk(pkt, chunk);
557
558 switch (status) {
559 case SCTP_XMIT_PMTU_FULL:
560 /* Send this packet. */
561 if ((error = sctp_packet_transmit(pkt)) == 0)
562 *start_timer = 1;
563
564 /* If we are retransmitting, we should only
565 * send a single packet.
566 */
567 if (rtx_timeout) {
568 list_add(lchunk, lqueue);
569 lchunk = NULL;
570 }
571
572 /* Bundle lchunk in the next round. */
573 break;
574
575 case SCTP_XMIT_RWND_FULL:
576 /* Send this packet. */
577 if ((error = sctp_packet_transmit(pkt)) == 0)
578 *start_timer = 1;
579
580 /* Stop sending DATA as there is no more room
581 * at the receiver.
582 */
583 list_add(lchunk, lqueue);
584 lchunk = NULL;
585 break;
586
587 case SCTP_XMIT_NAGLE_DELAY:
588 /* Send this packet. */
589 if ((error = sctp_packet_transmit(pkt)) == 0)
590 *start_timer = 1;
591
592 /* Stop sending DATA because of nagle delay. */
593 list_add(lchunk, lqueue);
594 lchunk = NULL;
595 break;
596
597 default:
598 /* The append was successful, so add this chunk to
599 * the transmitted list.
600 */
601 list_add_tail(lchunk, &transport->transmitted);
602
603 /* Mark the chunk as ineligible for fast retransmit
604 * after it is retransmitted.
605 */
Vlad Yasevich27852c22006-02-02 16:57:31 -0800606 if (chunk->fast_retransmit > 0)
607 chunk->fast_retransmit = -1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608
609 *start_timer = 1;
610 q->empty = 0;
611
612 /* Retrieve a new chunk to bundle. */
613 lchunk = sctp_list_dequeue(lqueue);
614 break;
615 };
616
617 /* If we are here due to a retransmit timeout or a fast
618 * retransmit and if there are any chunks left in the retransmit
619 * queue that could not fit in the PMTU sized packet, they need * to be marked as ineligible for a subsequent fast retransmit.
620 */
621 if (rtx_timeout && !lchunk) {
622 list_for_each(lchunk1, lqueue) {
623 chunk1 = list_entry(lchunk1, struct sctp_chunk,
624 transmitted_list);
Vlad Yasevich27852c22006-02-02 16:57:31 -0800625 if (chunk1->fast_retransmit > 0)
626 chunk1->fast_retransmit = -1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700627 }
628 }
629 }
630
631 return error;
632}
633
634/* Cork the outqueue so queued chunks are really queued. */
635int sctp_outq_uncork(struct sctp_outq *q)
636{
637 int error = 0;
638 if (q->cork) {
639 q->cork = 0;
640 error = sctp_outq_flush(q, 0);
641 }
642 return error;
643}
644
645/*
646 * Try to flush an outqueue.
647 *
648 * Description: Send everything in q which we legally can, subject to
649 * congestion limitations.
650 * * Note: This function can be called from multiple contexts so appropriate
651 * locking concerns must be made. Today we use the sock lock to protect
652 * this function.
653 */
654int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout)
655{
656 struct sctp_packet *packet;
657 struct sctp_packet singleton;
658 struct sctp_association *asoc = q->asoc;
659 __u16 sport = asoc->base.bind_addr.port;
660 __u16 dport = asoc->peer.port;
661 __u32 vtag = asoc->peer.i.init_tag;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700662 struct sctp_transport *transport = NULL;
663 struct sctp_transport *new_transport;
David S. Miller79af02c2005-07-08 21:47:49 -0700664 struct sctp_chunk *chunk, *tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700665 sctp_xmit_t status;
666 int error = 0;
667 int start_timer = 0;
668
669 /* These transports have chunks to send. */
670 struct list_head transport_list;
671 struct list_head *ltransport;
672
673 INIT_LIST_HEAD(&transport_list);
674 packet = NULL;
675
676 /*
677 * 6.10 Bundling
678 * ...
679 * When bundling control chunks with DATA chunks, an
680 * endpoint MUST place control chunks first in the outbound
681 * SCTP packet. The transmitter MUST transmit DATA chunks
682 * within a SCTP packet in increasing order of TSN.
683 * ...
684 */
685
David S. Miller79af02c2005-07-08 21:47:49 -0700686 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) {
687 list_del_init(&chunk->list);
688
Linus Torvalds1da177e2005-04-16 15:20:36 -0700689 /* Pick the right transport to use. */
690 new_transport = chunk->transport;
691
692 if (!new_transport) {
693 new_transport = asoc->peer.active_path;
Frank Filz3f7a87d2005-06-20 13:14:57 -0700694 } else if (new_transport->state == SCTP_INACTIVE) {
695 /* If the chunk is Heartbeat or Heartbeat Ack,
696 * send it to chunk->transport, even if it's
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697 * inactive.
698 *
699 * 3.3.6 Heartbeat Acknowledgement:
700 * ...
701 * A HEARTBEAT ACK is always sent to the source IP
702 * address of the IP datagram containing the
703 * HEARTBEAT chunk to which this ack is responding.
704 * ...
705 */
706 if (chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT &&
707 chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT_ACK)
708 new_transport = asoc->peer.active_path;
709 }
710
711 /* Are we switching transports?
712 * Take care of transport locks.
713 */
714 if (new_transport != transport) {
715 transport = new_transport;
716 if (list_empty(&transport->send_ready)) {
717 list_add_tail(&transport->send_ready,
718 &transport_list);
719 }
720 packet = &transport->packet;
721 sctp_packet_config(packet, vtag,
722 asoc->peer.ecn_capable);
723 }
724
725 switch (chunk->chunk_hdr->type) {
726 /*
727 * 6.10 Bundling
728 * ...
729 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN
730 * COMPLETE with any other chunks. [Send them immediately.]
731 */
732 case SCTP_CID_INIT:
733 case SCTP_CID_INIT_ACK:
734 case SCTP_CID_SHUTDOWN_COMPLETE:
735 sctp_packet_init(&singleton, transport, sport, dport);
736 sctp_packet_config(&singleton, vtag, 0);
737 sctp_packet_append_chunk(&singleton, chunk);
738 error = sctp_packet_transmit(&singleton);
739 if (error < 0)
740 return error;
741 break;
742
743 case SCTP_CID_ABORT:
744 case SCTP_CID_SACK:
745 case SCTP_CID_HEARTBEAT:
746 case SCTP_CID_HEARTBEAT_ACK:
747 case SCTP_CID_SHUTDOWN:
748 case SCTP_CID_SHUTDOWN_ACK:
749 case SCTP_CID_ERROR:
750 case SCTP_CID_COOKIE_ECHO:
751 case SCTP_CID_COOKIE_ACK:
752 case SCTP_CID_ECN_ECNE:
753 case SCTP_CID_ECN_CWR:
754 case SCTP_CID_ASCONF:
755 case SCTP_CID_ASCONF_ACK:
756 case SCTP_CID_FWD_TSN:
757 sctp_packet_transmit_chunk(packet, chunk);
758 break;
759
760 default:
761 /* We built a chunk with an illegal type! */
762 BUG();
763 };
764 }
765
766 /* Is it OK to send data chunks? */
767 switch (asoc->state) {
768 case SCTP_STATE_COOKIE_ECHOED:
769 /* Only allow bundling when this packet has a COOKIE-ECHO
770 * chunk.
771 */
772 if (!packet || !packet->has_cookie_echo)
773 break;
774
775 /* fallthru */
776 case SCTP_STATE_ESTABLISHED:
777 case SCTP_STATE_SHUTDOWN_PENDING:
778 case SCTP_STATE_SHUTDOWN_RECEIVED:
779 /*
780 * RFC 2960 6.1 Transmission of DATA Chunks
781 *
782 * C) When the time comes for the sender to transmit,
783 * before sending new DATA chunks, the sender MUST
784 * first transmit any outstanding DATA chunks which
785 * are marked for retransmission (limited by the
786 * current cwnd).
787 */
788 if (!list_empty(&q->retransmit)) {
789 if (transport == asoc->peer.retran_path)
790 goto retran;
791
792 /* Switch transports & prepare the packet. */
793
794 transport = asoc->peer.retran_path;
795
796 if (list_empty(&transport->send_ready)) {
797 list_add_tail(&transport->send_ready,
798 &transport_list);
799 }
800
801 packet = &transport->packet;
802 sctp_packet_config(packet, vtag,
803 asoc->peer.ecn_capable);
804 retran:
805 error = sctp_outq_flush_rtx(q, packet,
806 rtx_timeout, &start_timer);
807
808 if (start_timer)
809 sctp_transport_reset_timers(transport);
810
811 /* This can happen on COOKIE-ECHO resend. Only
812 * one chunk can get bundled with a COOKIE-ECHO.
813 */
814 if (packet->has_cookie_echo)
815 goto sctp_flush_out;
816
817 /* Don't send new data if there is still data
818 * waiting to retransmit.
819 */
820 if (!list_empty(&q->retransmit))
821 goto sctp_flush_out;
822 }
823
824 /* Finally, transmit new packets. */
825 start_timer = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700826 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) {
827 /* RFC 2960 6.5 Every DATA chunk MUST carry a valid
828 * stream identifier.
829 */
830 if (chunk->sinfo.sinfo_stream >=
831 asoc->c.sinit_num_ostreams) {
832
833 /* Mark as failed send. */
834 sctp_chunk_fail(chunk, SCTP_ERROR_INV_STRM);
835 sctp_chunk_free(chunk);
836 continue;
837 }
838
839 /* Has this chunk expired? */
840 if (sctp_chunk_abandoned(chunk)) {
841 sctp_chunk_fail(chunk, 0);
842 sctp_chunk_free(chunk);
843 continue;
844 }
845
846 /* If there is a specified transport, use it.
847 * Otherwise, we want to use the active path.
848 */
849 new_transport = chunk->transport;
Frank Filz3f7a87d2005-06-20 13:14:57 -0700850 if (!new_transport ||
851 new_transport->state == SCTP_INACTIVE)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700852 new_transport = asoc->peer.active_path;
853
854 /* Change packets if necessary. */
855 if (new_transport != transport) {
856 transport = new_transport;
857
858 /* Schedule to have this transport's
859 * packet flushed.
860 */
861 if (list_empty(&transport->send_ready)) {
862 list_add_tail(&transport->send_ready,
863 &transport_list);
864 }
865
866 packet = &transport->packet;
867 sctp_packet_config(packet, vtag,
868 asoc->peer.ecn_capable);
869 }
870
871 SCTP_DEBUG_PRINTK("sctp_outq_flush(%p, %p[%s]), ",
872 q, chunk,
873 chunk && chunk->chunk_hdr ?
874 sctp_cname(SCTP_ST_CHUNK(
875 chunk->chunk_hdr->type))
876 : "Illegal Chunk");
877
878 SCTP_DEBUG_PRINTK("TX TSN 0x%x skb->head "
879 "%p skb->users %d.\n",
880 ntohl(chunk->subh.data_hdr->tsn),
881 chunk->skb ?chunk->skb->head : NULL,
882 chunk->skb ?
883 atomic_read(&chunk->skb->users) : -1);
884
885 /* Add the chunk to the packet. */
886 status = sctp_packet_transmit_chunk(packet, chunk);
887
888 switch (status) {
889 case SCTP_XMIT_PMTU_FULL:
890 case SCTP_XMIT_RWND_FULL:
891 case SCTP_XMIT_NAGLE_DELAY:
892 /* We could not append this chunk, so put
893 * the chunk back on the output queue.
894 */
895 SCTP_DEBUG_PRINTK("sctp_outq_flush: could "
896 "not transmit TSN: 0x%x, status: %d\n",
897 ntohl(chunk->subh.data_hdr->tsn),
898 status);
899 sctp_outq_head_data(q, chunk);
900 goto sctp_flush_out;
901 break;
902
903 case SCTP_XMIT_OK:
904 break;
905
906 default:
907 BUG();
908 }
909
910 /* BUG: We assume that the sctp_packet_transmit()
911 * call below will succeed all the time and add the
912 * chunk to the transmitted list and restart the
913 * timers.
914 * It is possible that the call can fail under OOM
915 * conditions.
916 *
917 * Is this really a problem? Won't this behave
918 * like a lost TSN?
919 */
920 list_add_tail(&chunk->transmitted_list,
921 &transport->transmitted);
922
923 sctp_transport_reset_timers(transport);
924
925 q->empty = 0;
926
927 /* Only let one DATA chunk get bundled with a
928 * COOKIE-ECHO chunk.
929 */
930 if (packet->has_cookie_echo)
931 goto sctp_flush_out;
932 }
933 break;
934
935 default:
936 /* Do nothing. */
937 break;
938 }
939
940sctp_flush_out:
941
942 /* Before returning, examine all the transports touched in
943 * this call. Right now, we bluntly force clear all the
944 * transports. Things might change after we implement Nagle.
945 * But such an examination is still required.
946 *
947 * --xguo
948 */
949 while ((ltransport = sctp_list_dequeue(&transport_list)) != NULL ) {
950 struct sctp_transport *t = list_entry(ltransport,
951 struct sctp_transport,
952 send_ready);
953 packet = &t->packet;
954 if (!sctp_packet_empty(packet))
955 error = sctp_packet_transmit(packet);
956 }
957
958 return error;
959}
960
961/* Update unack_data based on the incoming SACK chunk */
962static void sctp_sack_update_unack_data(struct sctp_association *assoc,
963 struct sctp_sackhdr *sack)
964{
965 sctp_sack_variable_t *frags;
966 __u16 unack_data;
967 int i;
968
969 unack_data = assoc->next_tsn - assoc->ctsn_ack_point - 1;
970
971 frags = sack->variable;
972 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); i++) {
973 unack_data -= ((ntohs(frags[i].gab.end) -
974 ntohs(frags[i].gab.start) + 1));
975 }
976
977 assoc->unack_data = unack_data;
978}
979
980/* Return the highest new tsn that is acknowledged by the given SACK chunk. */
981static __u32 sctp_highest_new_tsn(struct sctp_sackhdr *sack,
982 struct sctp_association *asoc)
983{
984 struct list_head *ltransport, *lchunk;
985 struct sctp_transport *transport;
986 struct sctp_chunk *chunk;
987 __u32 highest_new_tsn, tsn;
988 struct list_head *transport_list = &asoc->peer.transport_addr_list;
989
990 highest_new_tsn = ntohl(sack->cum_tsn_ack);
991
992 list_for_each(ltransport, transport_list) {
993 transport = list_entry(ltransport, struct sctp_transport,
994 transports);
995 list_for_each(lchunk, &transport->transmitted) {
996 chunk = list_entry(lchunk, struct sctp_chunk,
997 transmitted_list);
998 tsn = ntohl(chunk->subh.data_hdr->tsn);
999
1000 if (!chunk->tsn_gap_acked &&
1001 TSN_lt(highest_new_tsn, tsn) &&
1002 sctp_acked(sack, tsn))
1003 highest_new_tsn = tsn;
1004 }
1005 }
1006
1007 return highest_new_tsn;
1008}
1009
1010/* This is where we REALLY process a SACK.
1011 *
1012 * Process the SACK against the outqueue. Mostly, this just frees
1013 * things off the transmitted queue.
1014 */
1015int sctp_outq_sack(struct sctp_outq *q, struct sctp_sackhdr *sack)
1016{
1017 struct sctp_association *asoc = q->asoc;
1018 struct sctp_transport *transport;
1019 struct sctp_chunk *tchunk = NULL;
1020 struct list_head *lchunk, *transport_list, *pos, *temp;
1021 sctp_sack_variable_t *frags = sack->variable;
1022 __u32 sack_ctsn, ctsn, tsn;
1023 __u32 highest_tsn, highest_new_tsn;
1024 __u32 sack_a_rwnd;
1025 unsigned outstanding;
1026 struct sctp_transport *primary = asoc->peer.primary_path;
1027 int count_of_newacks = 0;
1028
1029 /* Grab the association's destination address list. */
1030 transport_list = &asoc->peer.transport_addr_list;
1031
1032 sack_ctsn = ntohl(sack->cum_tsn_ack);
1033
1034 /*
1035 * SFR-CACC algorithm:
1036 * On receipt of a SACK the sender SHOULD execute the
1037 * following statements.
1038 *
1039 * 1) If the cumulative ack in the SACK passes next tsn_at_change
1040 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be
1041 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for
1042 * all destinations.
1043 */
1044 if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) {
1045 primary->cacc.changeover_active = 0;
1046 list_for_each(pos, transport_list) {
1047 transport = list_entry(pos, struct sctp_transport,
1048 transports);
1049 transport->cacc.cycling_changeover = 0;
1050 }
1051 }
1052
1053 /*
1054 * SFR-CACC algorithm:
1055 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE
1056 * is set the receiver of the SACK MUST take the following actions:
1057 *
1058 * A) Initialize the cacc_saw_newack to 0 for all destination
1059 * addresses.
1060 */
1061 if (sack->num_gap_ack_blocks > 0 &&
1062 primary->cacc.changeover_active) {
1063 list_for_each(pos, transport_list) {
1064 transport = list_entry(pos, struct sctp_transport,
1065 transports);
1066 transport->cacc.cacc_saw_newack = 0;
1067 }
1068 }
1069
1070 /* Get the highest TSN in the sack. */
1071 highest_tsn = sack_ctsn;
1072 if (sack->num_gap_ack_blocks)
1073 highest_tsn +=
1074 ntohs(frags[ntohs(sack->num_gap_ack_blocks) - 1].gab.end);
1075
1076 if (TSN_lt(asoc->highest_sacked, highest_tsn)) {
1077 highest_new_tsn = highest_tsn;
1078 asoc->highest_sacked = highest_tsn;
1079 } else {
1080 highest_new_tsn = sctp_highest_new_tsn(sack, asoc);
1081 }
1082
1083 /* Run through the retransmit queue. Credit bytes received
1084 * and free those chunks that we can.
1085 */
1086 sctp_check_transmitted(q, &q->retransmit, NULL, sack, highest_new_tsn);
1087 sctp_mark_missing(q, &q->retransmit, NULL, highest_new_tsn, 0);
1088
1089 /* Run through the transmitted queue.
1090 * Credit bytes received and free those chunks which we can.
1091 *
1092 * This is a MASSIVE candidate for optimization.
1093 */
1094 list_for_each(pos, transport_list) {
1095 transport = list_entry(pos, struct sctp_transport,
1096 transports);
1097 sctp_check_transmitted(q, &transport->transmitted,
1098 transport, sack, highest_new_tsn);
1099 /*
1100 * SFR-CACC algorithm:
1101 * C) Let count_of_newacks be the number of
1102 * destinations for which cacc_saw_newack is set.
1103 */
1104 if (transport->cacc.cacc_saw_newack)
1105 count_of_newacks ++;
1106 }
1107
1108 list_for_each(pos, transport_list) {
1109 transport = list_entry(pos, struct sctp_transport,
1110 transports);
1111 sctp_mark_missing(q, &transport->transmitted, transport,
1112 highest_new_tsn, count_of_newacks);
1113 }
1114
1115 /* Move the Cumulative TSN Ack Point if appropriate. */
1116 if (TSN_lt(asoc->ctsn_ack_point, sack_ctsn))
1117 asoc->ctsn_ack_point = sack_ctsn;
1118
1119 /* Update unack_data field in the assoc. */
1120 sctp_sack_update_unack_data(asoc, sack);
1121
1122 ctsn = asoc->ctsn_ack_point;
1123
1124 /* Throw away stuff rotting on the sack queue. */
1125 list_for_each_safe(lchunk, temp, &q->sacked) {
1126 tchunk = list_entry(lchunk, struct sctp_chunk,
1127 transmitted_list);
1128 tsn = ntohl(tchunk->subh.data_hdr->tsn);
1129 if (TSN_lte(tsn, ctsn))
1130 sctp_chunk_free(tchunk);
1131 }
1132
1133 /* ii) Set rwnd equal to the newly received a_rwnd minus the
1134 * number of bytes still outstanding after processing the
1135 * Cumulative TSN Ack and the Gap Ack Blocks.
1136 */
1137
1138 sack_a_rwnd = ntohl(sack->a_rwnd);
1139 outstanding = q->outstanding_bytes;
1140
1141 if (outstanding < sack_a_rwnd)
1142 sack_a_rwnd -= outstanding;
1143 else
1144 sack_a_rwnd = 0;
1145
1146 asoc->peer.rwnd = sack_a_rwnd;
1147
1148 sctp_generate_fwdtsn(q, sack_ctsn);
1149
1150 SCTP_DEBUG_PRINTK("%s: sack Cumulative TSN Ack is 0x%x.\n",
1151 __FUNCTION__, sack_ctsn);
1152 SCTP_DEBUG_PRINTK("%s: Cumulative TSN Ack of association, "
1153 "%p is 0x%x. Adv peer ack point: 0x%x\n",
1154 __FUNCTION__, asoc, ctsn, asoc->adv_peer_ack_point);
1155
1156 /* See if all chunks are acked.
1157 * Make sure the empty queue handler will get run later.
1158 */
David S. Miller79af02c2005-07-08 21:47:49 -07001159 q->empty = (list_empty(&q->out_chunk_list) &&
1160 list_empty(&q->control_chunk_list) &&
1161 list_empty(&q->retransmit));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001162 if (!q->empty)
1163 goto finish;
1164
1165 list_for_each(pos, transport_list) {
1166 transport = list_entry(pos, struct sctp_transport,
1167 transports);
1168 q->empty = q->empty && list_empty(&transport->transmitted);
1169 if (!q->empty)
1170 goto finish;
1171 }
1172
1173 SCTP_DEBUG_PRINTK("sack queue is empty.\n");
1174finish:
1175 return q->empty;
1176}
1177
1178/* Is the outqueue empty? */
1179int sctp_outq_is_empty(const struct sctp_outq *q)
1180{
1181 return q->empty;
1182}
1183
1184/********************************************************************
1185 * 2nd Level Abstractions
1186 ********************************************************************/
1187
1188/* Go through a transport's transmitted list or the association's retransmit
1189 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked.
1190 * The retransmit list will not have an associated transport.
1191 *
1192 * I added coherent debug information output. --xguo
1193 *
1194 * Instead of printing 'sacked' or 'kept' for each TSN on the
1195 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5.
1196 * KEPT TSN6-TSN7, etc.
1197 */
1198static void sctp_check_transmitted(struct sctp_outq *q,
1199 struct list_head *transmitted_queue,
1200 struct sctp_transport *transport,
1201 struct sctp_sackhdr *sack,
1202 __u32 highest_new_tsn_in_sack)
1203{
1204 struct list_head *lchunk;
1205 struct sctp_chunk *tchunk;
1206 struct list_head tlist;
1207 __u32 tsn;
1208 __u32 sack_ctsn;
1209 __u32 rtt;
1210 __u8 restart_timer = 0;
1211 int bytes_acked = 0;
1212
1213 /* These state variables are for coherent debug output. --xguo */
1214
1215#if SCTP_DEBUG
1216 __u32 dbg_ack_tsn = 0; /* An ACKed TSN range starts here... */
1217 __u32 dbg_last_ack_tsn = 0; /* ...and finishes here. */
1218 __u32 dbg_kept_tsn = 0; /* An un-ACKed range starts here... */
1219 __u32 dbg_last_kept_tsn = 0; /* ...and finishes here. */
1220
1221 /* 0 : The last TSN was ACKed.
1222 * 1 : The last TSN was NOT ACKed (i.e. KEPT).
1223 * -1: We need to initialize.
1224 */
1225 int dbg_prt_state = -1;
1226#endif /* SCTP_DEBUG */
1227
1228 sack_ctsn = ntohl(sack->cum_tsn_ack);
1229
1230 INIT_LIST_HEAD(&tlist);
1231
1232 /* The while loop will skip empty transmitted queues. */
1233 while (NULL != (lchunk = sctp_list_dequeue(transmitted_queue))) {
1234 tchunk = list_entry(lchunk, struct sctp_chunk,
1235 transmitted_list);
1236
1237 if (sctp_chunk_abandoned(tchunk)) {
1238 /* Move the chunk to abandoned list. */
1239 sctp_insert_list(&q->abandoned, lchunk);
1240 continue;
1241 }
1242
1243 tsn = ntohl(tchunk->subh.data_hdr->tsn);
1244 if (sctp_acked(sack, tsn)) {
1245 /* If this queue is the retransmit queue, the
1246 * retransmit timer has already reclaimed
1247 * the outstanding bytes for this chunk, so only
1248 * count bytes associated with a transport.
1249 */
1250 if (transport) {
1251 /* If this chunk is being used for RTT
1252 * measurement, calculate the RTT and update
1253 * the RTO using this value.
1254 *
1255 * 6.3.1 C5) Karn's algorithm: RTT measurements
1256 * MUST NOT be made using packets that were
1257 * retransmitted (and thus for which it is
1258 * ambiguous whether the reply was for the
1259 * first instance of the packet or a later
1260 * instance).
1261 */
1262 if (!tchunk->tsn_gap_acked &&
1263 !tchunk->resent &&
1264 tchunk->rtt_in_progress) {
1265 rtt = jiffies - tchunk->sent_at;
1266 sctp_transport_update_rto(transport,
1267 rtt);
1268 }
1269 }
1270 if (TSN_lte(tsn, sack_ctsn)) {
1271 /* RFC 2960 6.3.2 Retransmission Timer Rules
1272 *
1273 * R3) Whenever a SACK is received
1274 * that acknowledges the DATA chunk
1275 * with the earliest outstanding TSN
1276 * for that address, restart T3-rtx
1277 * timer for that address with its
1278 * current RTO.
1279 */
1280 restart_timer = 1;
1281
1282 if (!tchunk->tsn_gap_acked) {
1283 tchunk->tsn_gap_acked = 1;
1284 bytes_acked += sctp_data_size(tchunk);
1285 /*
1286 * SFR-CACC algorithm:
1287 * 2) If the SACK contains gap acks
1288 * and the flag CHANGEOVER_ACTIVE is
1289 * set the receiver of the SACK MUST
1290 * take the following action:
1291 *
1292 * B) For each TSN t being acked that
1293 * has not been acked in any SACK so
1294 * far, set cacc_saw_newack to 1 for
1295 * the destination that the TSN was
1296 * sent to.
1297 */
1298 if (transport &&
1299 sack->num_gap_ack_blocks &&
1300 q->asoc->peer.primary_path->cacc.
1301 changeover_active)
1302 transport->cacc.cacc_saw_newack
1303 = 1;
1304 }
1305
1306 list_add_tail(&tchunk->transmitted_list,
1307 &q->sacked);
1308 } else {
1309 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2
1310 * M2) Each time a SACK arrives reporting
1311 * 'Stray DATA chunk(s)' record the highest TSN
1312 * reported as newly acknowledged, call this
1313 * value 'HighestTSNinSack'. A newly
1314 * acknowledged DATA chunk is one not
1315 * previously acknowledged in a SACK.
1316 *
1317 * When the SCTP sender of data receives a SACK
1318 * chunk that acknowledges, for the first time,
1319 * the receipt of a DATA chunk, all the still
1320 * unacknowledged DATA chunks whose TSN is
1321 * older than that newly acknowledged DATA
1322 * chunk, are qualified as 'Stray DATA chunks'.
1323 */
1324 if (!tchunk->tsn_gap_acked) {
1325 tchunk->tsn_gap_acked = 1;
1326 bytes_acked += sctp_data_size(tchunk);
1327 }
1328 list_add_tail(lchunk, &tlist);
1329 }
1330
1331#if SCTP_DEBUG
1332 switch (dbg_prt_state) {
1333 case 0: /* last TSN was ACKed */
1334 if (dbg_last_ack_tsn + 1 == tsn) {
1335 /* This TSN belongs to the
1336 * current ACK range.
1337 */
1338 break;
1339 }
1340
1341 if (dbg_last_ack_tsn != dbg_ack_tsn) {
1342 /* Display the end of the
1343 * current range.
1344 */
1345 SCTP_DEBUG_PRINTK("-%08x",
1346 dbg_last_ack_tsn);
1347 }
1348
1349 /* Start a new range. */
1350 SCTP_DEBUG_PRINTK(",%08x", tsn);
1351 dbg_ack_tsn = tsn;
1352 break;
1353
1354 case 1: /* The last TSN was NOT ACKed. */
1355 if (dbg_last_kept_tsn != dbg_kept_tsn) {
1356 /* Display the end of current range. */
1357 SCTP_DEBUG_PRINTK("-%08x",
1358 dbg_last_kept_tsn);
1359 }
1360
1361 SCTP_DEBUG_PRINTK("\n");
1362
1363 /* FALL THROUGH... */
1364 default:
1365 /* This is the first-ever TSN we examined. */
1366 /* Start a new range of ACK-ed TSNs. */
1367 SCTP_DEBUG_PRINTK("ACKed: %08x", tsn);
1368 dbg_prt_state = 0;
1369 dbg_ack_tsn = tsn;
1370 };
1371
1372 dbg_last_ack_tsn = tsn;
1373#endif /* SCTP_DEBUG */
1374
1375 } else {
1376 if (tchunk->tsn_gap_acked) {
1377 SCTP_DEBUG_PRINTK("%s: Receiver reneged on "
1378 "data TSN: 0x%x\n",
1379 __FUNCTION__,
1380 tsn);
1381 tchunk->tsn_gap_acked = 0;
1382
1383 bytes_acked -= sctp_data_size(tchunk);
1384
1385 /* RFC 2960 6.3.2 Retransmission Timer Rules
1386 *
1387 * R4) Whenever a SACK is received missing a
1388 * TSN that was previously acknowledged via a
1389 * Gap Ack Block, start T3-rtx for the
1390 * destination address to which the DATA
1391 * chunk was originally
1392 * transmitted if it is not already running.
1393 */
1394 restart_timer = 1;
1395 }
1396
1397 list_add_tail(lchunk, &tlist);
1398
1399#if SCTP_DEBUG
1400 /* See the above comments on ACK-ed TSNs. */
1401 switch (dbg_prt_state) {
1402 case 1:
1403 if (dbg_last_kept_tsn + 1 == tsn)
1404 break;
1405
1406 if (dbg_last_kept_tsn != dbg_kept_tsn)
1407 SCTP_DEBUG_PRINTK("-%08x",
1408 dbg_last_kept_tsn);
1409
1410 SCTP_DEBUG_PRINTK(",%08x", tsn);
1411 dbg_kept_tsn = tsn;
1412 break;
1413
1414 case 0:
1415 if (dbg_last_ack_tsn != dbg_ack_tsn)
1416 SCTP_DEBUG_PRINTK("-%08x",
1417 dbg_last_ack_tsn);
1418 SCTP_DEBUG_PRINTK("\n");
1419
1420 /* FALL THROUGH... */
1421 default:
1422 SCTP_DEBUG_PRINTK("KEPT: %08x",tsn);
1423 dbg_prt_state = 1;
1424 dbg_kept_tsn = tsn;
1425 };
1426
1427 dbg_last_kept_tsn = tsn;
1428#endif /* SCTP_DEBUG */
1429 }
1430 }
1431
1432#if SCTP_DEBUG
1433 /* Finish off the last range, displaying its ending TSN. */
1434 switch (dbg_prt_state) {
1435 case 0:
1436 if (dbg_last_ack_tsn != dbg_ack_tsn) {
1437 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_ack_tsn);
1438 } else {
1439 SCTP_DEBUG_PRINTK("\n");
1440 }
1441 break;
1442
1443 case 1:
1444 if (dbg_last_kept_tsn != dbg_kept_tsn) {
1445 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_kept_tsn);
1446 } else {
1447 SCTP_DEBUG_PRINTK("\n");
1448 }
1449 };
1450#endif /* SCTP_DEBUG */
1451 if (transport) {
1452 if (bytes_acked) {
1453 /* 8.2. When an outstanding TSN is acknowledged,
1454 * the endpoint shall clear the error counter of
1455 * the destination transport address to which the
1456 * DATA chunk was last sent.
1457 * The association's overall error counter is
1458 * also cleared.
1459 */
1460 transport->error_count = 0;
1461 transport->asoc->overall_error_count = 0;
1462
1463 /* Mark the destination transport address as
1464 * active if it is not so marked.
1465 */
Frank Filz3f7a87d2005-06-20 13:14:57 -07001466 if (transport->state == SCTP_INACTIVE) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001467 sctp_assoc_control_transport(
1468 transport->asoc,
1469 transport,
1470 SCTP_TRANSPORT_UP,
1471 SCTP_RECEIVED_SACK);
1472 }
1473
1474 sctp_transport_raise_cwnd(transport, sack_ctsn,
1475 bytes_acked);
1476
1477 transport->flight_size -= bytes_acked;
1478 q->outstanding_bytes -= bytes_acked;
1479 } else {
1480 /* RFC 2960 6.1, sctpimpguide-06 2.15.2
1481 * When a sender is doing zero window probing, it
1482 * should not timeout the association if it continues
1483 * to receive new packets from the receiver. The
1484 * reason is that the receiver MAY keep its window
1485 * closed for an indefinite time.
1486 * A sender is doing zero window probing when the
1487 * receiver's advertised window is zero, and there is
1488 * only one data chunk in flight to the receiver.
1489 */
1490 if (!q->asoc->peer.rwnd &&
1491 !list_empty(&tlist) &&
1492 (sack_ctsn+2 == q->asoc->next_tsn)) {
1493 SCTP_DEBUG_PRINTK("%s: SACK received for zero "
1494 "window probe: %u\n",
1495 __FUNCTION__, sack_ctsn);
1496 q->asoc->overall_error_count = 0;
1497 transport->error_count = 0;
1498 }
1499 }
1500
1501 /* RFC 2960 6.3.2 Retransmission Timer Rules
1502 *
1503 * R2) Whenever all outstanding data sent to an address have
1504 * been acknowledged, turn off the T3-rtx timer of that
1505 * address.
1506 */
1507 if (!transport->flight_size) {
1508 if (timer_pending(&transport->T3_rtx_timer) &&
1509 del_timer(&transport->T3_rtx_timer)) {
1510 sctp_transport_put(transport);
1511 }
1512 } else if (restart_timer) {
1513 if (!mod_timer(&transport->T3_rtx_timer,
1514 jiffies + transport->rto))
1515 sctp_transport_hold(transport);
1516 }
1517 }
1518
1519 list_splice(&tlist, transmitted_queue);
1520}
1521
1522/* Mark chunks as missing and consequently may get retransmitted. */
1523static void sctp_mark_missing(struct sctp_outq *q,
1524 struct list_head *transmitted_queue,
1525 struct sctp_transport *transport,
1526 __u32 highest_new_tsn_in_sack,
1527 int count_of_newacks)
1528{
1529 struct sctp_chunk *chunk;
1530 struct list_head *pos;
1531 __u32 tsn;
1532 char do_fast_retransmit = 0;
1533 struct sctp_transport *primary = q->asoc->peer.primary_path;
1534
1535 list_for_each(pos, transmitted_queue) {
1536
1537 chunk = list_entry(pos, struct sctp_chunk, transmitted_list);
1538 tsn = ntohl(chunk->subh.data_hdr->tsn);
1539
1540 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all
1541 * 'Unacknowledged TSN's', if the TSN number of an
1542 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack'
1543 * value, increment the 'TSN.Missing.Report' count on that
1544 * chunk if it has NOT been fast retransmitted or marked for
1545 * fast retransmit already.
1546 */
1547 if (!chunk->fast_retransmit &&
1548 !chunk->tsn_gap_acked &&
1549 TSN_lt(tsn, highest_new_tsn_in_sack)) {
1550
1551 /* SFR-CACC may require us to skip marking
1552 * this chunk as missing.
1553 */
1554 if (!transport || !sctp_cacc_skip(primary, transport,
1555 count_of_newacks, tsn)) {
1556 chunk->tsn_missing_report++;
1557
1558 SCTP_DEBUG_PRINTK(
1559 "%s: TSN 0x%x missing counter: %d\n",
1560 __FUNCTION__, tsn,
1561 chunk->tsn_missing_report);
1562 }
1563 }
1564 /*
1565 * M4) If any DATA chunk is found to have a
1566 * 'TSN.Missing.Report'
Vlad Yasevich27852c22006-02-02 16:57:31 -08001567 * value larger than or equal to 3, mark that chunk for
Linus Torvalds1da177e2005-04-16 15:20:36 -07001568 * retransmission and start the fast retransmit procedure.
1569 */
1570
Vlad Yasevich27852c22006-02-02 16:57:31 -08001571 if (chunk->tsn_missing_report >= 3) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001572 chunk->fast_retransmit = 1;
1573 do_fast_retransmit = 1;
1574 }
1575 }
1576
1577 if (transport) {
1578 if (do_fast_retransmit)
1579 sctp_retransmit(q, transport, SCTP_RTXR_FAST_RTX);
1580
1581 SCTP_DEBUG_PRINTK("%s: transport: %p, cwnd: %d, "
1582 "ssthresh: %d, flight_size: %d, pba: %d\n",
1583 __FUNCTION__, transport, transport->cwnd,
1584 transport->ssthresh, transport->flight_size,
1585 transport->partial_bytes_acked);
1586 }
1587}
1588
1589/* Is the given TSN acked by this packet? */
1590static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn)
1591{
1592 int i;
1593 sctp_sack_variable_t *frags;
1594 __u16 gap;
1595 __u32 ctsn = ntohl(sack->cum_tsn_ack);
1596
1597 if (TSN_lte(tsn, ctsn))
1598 goto pass;
1599
1600 /* 3.3.4 Selective Acknowledgement (SACK) (3):
1601 *
1602 * Gap Ack Blocks:
1603 * These fields contain the Gap Ack Blocks. They are repeated
1604 * for each Gap Ack Block up to the number of Gap Ack Blocks
1605 * defined in the Number of Gap Ack Blocks field. All DATA
1606 * chunks with TSNs greater than or equal to (Cumulative TSN
1607 * Ack + Gap Ack Block Start) and less than or equal to
1608 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack
1609 * Block are assumed to have been received correctly.
1610 */
1611
1612 frags = sack->variable;
1613 gap = tsn - ctsn;
1614 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); ++i) {
1615 if (TSN_lte(ntohs(frags[i].gab.start), gap) &&
1616 TSN_lte(gap, ntohs(frags[i].gab.end)))
1617 goto pass;
1618 }
1619
1620 return 0;
1621pass:
1622 return 1;
1623}
1624
1625static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip *skiplist,
1626 int nskips, __u16 stream)
1627{
1628 int i;
1629
1630 for (i = 0; i < nskips; i++) {
1631 if (skiplist[i].stream == stream)
1632 return i;
1633 }
1634 return i;
1635}
1636
1637/* Create and add a fwdtsn chunk to the outq's control queue if needed. */
1638static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 ctsn)
1639{
1640 struct sctp_association *asoc = q->asoc;
1641 struct sctp_chunk *ftsn_chunk = NULL;
1642 struct sctp_fwdtsn_skip ftsn_skip_arr[10];
1643 int nskips = 0;
1644 int skip_pos = 0;
1645 __u32 tsn;
1646 struct sctp_chunk *chunk;
1647 struct list_head *lchunk, *temp;
1648
1649 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the
1650 * received SACK.
1651 *
1652 * If (Advanced.Peer.Ack.Point < SackCumAck), then update
1653 * Advanced.Peer.Ack.Point to be equal to SackCumAck.
1654 */
1655 if (TSN_lt(asoc->adv_peer_ack_point, ctsn))
1656 asoc->adv_peer_ack_point = ctsn;
1657
1658 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point"
1659 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as
1660 * the chunk next in the out-queue space is marked as "abandoned" as
1661 * shown in the following example:
1662 *
1663 * Assuming that a SACK arrived with the Cumulative TSN ACK 102
1664 * and the Advanced.Peer.Ack.Point is updated to this value:
1665 *
1666 * out-queue at the end of ==> out-queue after Adv.Ack.Point
1667 * normal SACK processing local advancement
1668 * ... ...
1669 * Adv.Ack.Pt-> 102 acked 102 acked
1670 * 103 abandoned 103 abandoned
1671 * 104 abandoned Adv.Ack.P-> 104 abandoned
1672 * 105 105
1673 * 106 acked 106 acked
1674 * ... ...
1675 *
1676 * In this example, the data sender successfully advanced the
1677 * "Advanced.Peer.Ack.Point" from 102 to 104 locally.
1678 */
1679 list_for_each_safe(lchunk, temp, &q->abandoned) {
1680 chunk = list_entry(lchunk, struct sctp_chunk,
1681 transmitted_list);
1682 tsn = ntohl(chunk->subh.data_hdr->tsn);
1683
1684 /* Remove any chunks in the abandoned queue that are acked by
1685 * the ctsn.
1686 */
1687 if (TSN_lte(tsn, ctsn)) {
1688 list_del_init(lchunk);
1689 if (!chunk->tsn_gap_acked) {
David S. Miller79af02c2005-07-08 21:47:49 -07001690 chunk->transport->flight_size -=
1691 sctp_data_size(chunk);
1692 q->outstanding_bytes -= sctp_data_size(chunk);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001693 }
1694 sctp_chunk_free(chunk);
1695 } else {
1696 if (TSN_lte(tsn, asoc->adv_peer_ack_point+1)) {
1697 asoc->adv_peer_ack_point = tsn;
1698 if (chunk->chunk_hdr->flags &
1699 SCTP_DATA_UNORDERED)
1700 continue;
1701 skip_pos = sctp_get_skip_pos(&ftsn_skip_arr[0],
1702 nskips,
1703 chunk->subh.data_hdr->stream);
1704 ftsn_skip_arr[skip_pos].stream =
1705 chunk->subh.data_hdr->stream;
1706 ftsn_skip_arr[skip_pos].ssn =
1707 chunk->subh.data_hdr->ssn;
1708 if (skip_pos == nskips)
1709 nskips++;
1710 if (nskips == 10)
1711 break;
1712 } else
1713 break;
1714 }
1715 }
1716
1717 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point"
1718 * is greater than the Cumulative TSN ACK carried in the received
1719 * SACK, the data sender MUST send the data receiver a FORWARD TSN
1720 * chunk containing the latest value of the
1721 * "Advanced.Peer.Ack.Point".
1722 *
1723 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD
1724 * list each stream and sequence number in the forwarded TSN. This
1725 * information will enable the receiver to easily find any
1726 * stranded TSN's waiting on stream reorder queues. Each stream
1727 * SHOULD only be reported once; this means that if multiple
1728 * abandoned messages occur in the same stream then only the
1729 * highest abandoned stream sequence number is reported. If the
1730 * total size of the FORWARD TSN does NOT fit in a single MTU then
1731 * the sender of the FORWARD TSN SHOULD lower the
1732 * Advanced.Peer.Ack.Point to the last TSN that will fit in a
1733 * single MTU.
1734 */
1735 if (asoc->adv_peer_ack_point > ctsn)
1736 ftsn_chunk = sctp_make_fwdtsn(asoc, asoc->adv_peer_ack_point,
1737 nskips, &ftsn_skip_arr[0]);
1738
1739 if (ftsn_chunk) {
David S. Miller79af02c2005-07-08 21:47:49 -07001740 list_add_tail(&ftsn_chunk->list, &q->control_chunk_list);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001741 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
1742 }
1743}