ia64/linux-2.6.18-xen.hg

view net/sctp/outqueue.c @ 871:9cbcc9008446

xen/x86: don't initialize cpu_data[]'s apicid field on generic code

Afaict, this is not only redundant with the intialization done in
drivers/xen/core/smpboot.c, but actually results - at least for
secondary CPUs - in the Xen-specific value written to be later
overwritten with whatever the generic code determines (with no
guarantee that the two values are identical).

Signed-off-by: Jan Beulich <jbeulich@novell.com>
author Keir Fraser <keir.fraser@citrix.com>
date Thu May 14 10:09:15 2009 +0100 (2009-05-14)
parents 831230e53067
children
line source
1 /* 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 */
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 */
55 #include <net/sctp/sctp.h>
56 #include <net/sctp/sm.h>
58 /* Declare internal functions here. */
59 static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn);
60 static 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);
66 static 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);
72 static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 sack_ctsn);
74 /* Add data to the front of the queue. */
75 static inline void sctp_outq_head_data(struct sctp_outq *q,
76 struct sctp_chunk *ch)
77 {
78 list_add(&ch->list, &q->out_chunk_list);
79 q->out_qlen += ch->skb->len;
80 return;
81 }
83 /* Take data from the front of the queue. */
84 static inline struct sctp_chunk *sctp_outq_dequeue_data(struct sctp_outq *q)
85 {
86 struct sctp_chunk *ch = NULL;
88 if (!list_empty(&q->out_chunk_list)) {
89 struct list_head *entry = q->out_chunk_list.next;
91 ch = list_entry(entry, struct sctp_chunk, list);
92 list_del_init(entry);
93 q->out_qlen -= ch->skb->len;
94 }
95 return ch;
96 }
97 /* Add data chunk to the end of the queue. */
98 static inline void sctp_outq_tail_data(struct sctp_outq *q,
99 struct sctp_chunk *ch)
100 {
101 list_add_tail(&ch->list, &q->out_chunk_list);
102 q->out_qlen += ch->skb->len;
103 return;
104 }
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 */
112 static 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 }
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 */
128 static 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 }
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 */
143 static 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 }
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 */
164 static 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 }
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 */
186 static 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 }
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 */
202 void sctp_outq_init(struct sctp_association *asoc, struct sctp_outq *q)
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);
211 q->outstanding_bytes = 0;
212 q->empty = 1;
213 q->cork = 0;
215 q->malloced = 0;
216 q->out_qlen = 0;
217 }
219 /* Free the outqueue structure and any related pending chunks.
220 */
221 void sctp_outq_teardown(struct sctp_outq *q)
222 {
223 struct sctp_transport *transport;
224 struct list_head *lchunk, *pos, *temp;
225 struct sctp_chunk *chunk, *tmp;
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 }
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 }
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 }
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 }
266 /* Throw away any leftover data chunks. */
267 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) {
269 /* Mark as send failure. */
270 sctp_chunk_fail(chunk, q->error);
271 sctp_chunk_free(chunk);
272 }
274 q->error = 0;
276 /* Throw away any leftover control chunks. */
277 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) {
278 list_del_init(&chunk->list);
279 sctp_chunk_free(chunk);
280 }
281 }
283 /* Free the outqueue structure and any related pending chunks. */
284 void sctp_outq_free(struct sctp_outq *q)
285 {
286 /* Throw away leftover chunks. */
287 sctp_outq_teardown(q);
289 /* If we were kmalloc()'d, free the memory. */
290 if (q->malloced)
291 kfree(q);
292 }
294 /* Put a new chunk in an sctp_outq. */
295 int sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk)
296 {
297 int error = 0;
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");
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;
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");
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 {
343 list_add_tail(&chunk->list, &q->control_chunk_list);
344 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
345 }
347 if (error < 0)
348 return error;
350 if (!q->cork)
351 error = sctp_outq_flush(q, 0);
353 return error;
354 }
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 */
359 static 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;
366 nchunk = list_entry(new, struct sctp_chunk, transmitted_list);
367 ntsn = ntohl(nchunk->subh.data_hdr->tsn);
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 }
382 /* Mark all the eligible packets on a transport for retransmission. */
383 void 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;
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);
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 }
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 */
409 if ((fast_retransmit && (chunk->fast_retransmit > 0)) ||
410 (!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);
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;
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 }
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 }
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);
457 }
459 /* Mark all the eligible packets on a transport for retransmission and force
460 * one packet out.
461 */
462 void 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;
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 }
486 sctp_retransmit_mark(q, transport, fast_retransmit);
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);
494 error = sctp_outq_flush(q, /* rtx_timeout */ 1);
496 if (error)
497 q->asoc->base.sk->sk_err = -error;
498 }
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 */
508 static 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;
519 asoc = q->asoc;
520 lqueue = &q->retransmit;
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);
540 while (lchunk) {
541 chunk = list_entry(lchunk, struct sctp_chunk,
542 transmitted_list);
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 }
555 /* Attempt to append this chunk to the packet. */
556 status = sctp_packet_append_chunk(pkt, chunk);
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;
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 }
572 /* Bundle lchunk in the next round. */
573 break;
575 case SCTP_XMIT_RWND_FULL:
576 /* Send this packet. */
577 if ((error = sctp_packet_transmit(pkt)) == 0)
578 *start_timer = 1;
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;
587 case SCTP_XMIT_NAGLE_DELAY:
588 /* Send this packet. */
589 if ((error = sctp_packet_transmit(pkt)) == 0)
590 *start_timer = 1;
592 /* Stop sending DATA because of nagle delay. */
593 list_add(lchunk, lqueue);
594 lchunk = NULL;
595 break;
597 default:
598 /* The append was successful, so add this chunk to
599 * the transmitted list.
600 */
601 list_add_tail(lchunk, &transport->transmitted);
603 /* Mark the chunk as ineligible for fast retransmit
604 * after it is retransmitted.
605 */
606 if (chunk->fast_retransmit > 0)
607 chunk->fast_retransmit = -1;
609 *start_timer = 1;
610 q->empty = 0;
612 /* Retrieve a new chunk to bundle. */
613 lchunk = sctp_list_dequeue(lqueue);
614 break;
615 };
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);
625 if (chunk1->fast_retransmit > 0)
626 chunk1->fast_retransmit = -1;
627 }
628 }
629 }
631 return error;
632 }
634 /* Cork the outqueue so queued chunks are really queued. */
635 int 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 }
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 */
654 int 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;
662 struct sctp_transport *transport = NULL;
663 struct sctp_transport *new_transport;
664 struct sctp_chunk *chunk, *tmp;
665 sctp_xmit_t status;
666 int error = 0;
667 int start_timer = 0;
669 /* These transports have chunks to send. */
670 struct list_head transport_list;
671 struct list_head *ltransport;
673 INIT_LIST_HEAD(&transport_list);
674 packet = NULL;
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 */
686 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) {
687 list_del_init(&chunk->list);
689 /* Pick the right transport to use. */
690 new_transport = chunk->transport;
692 if (!new_transport) {
693 new_transport = asoc->peer.active_path;
694 } else if ((new_transport->state == SCTP_INACTIVE) ||
695 (new_transport->state == SCTP_UNCONFIRMED)) {
696 /* If the chunk is Heartbeat or Heartbeat Ack,
697 * send it to chunk->transport, even if it's
698 * inactive.
699 *
700 * 3.3.6 Heartbeat Acknowledgement:
701 * ...
702 * A HEARTBEAT ACK is always sent to the source IP
703 * address of the IP datagram containing the
704 * HEARTBEAT chunk to which this ack is responding.
705 * ...
706 */
707 if (chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT &&
708 chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT_ACK)
709 new_transport = asoc->peer.active_path;
710 }
712 /* Are we switching transports?
713 * Take care of transport locks.
714 */
715 if (new_transport != transport) {
716 transport = new_transport;
717 if (list_empty(&transport->send_ready)) {
718 list_add_tail(&transport->send_ready,
719 &transport_list);
720 }
721 packet = &transport->packet;
722 sctp_packet_config(packet, vtag,
723 asoc->peer.ecn_capable);
724 }
726 switch (chunk->chunk_hdr->type) {
727 /*
728 * 6.10 Bundling
729 * ...
730 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN
731 * COMPLETE with any other chunks. [Send them immediately.]
732 */
733 case SCTP_CID_INIT:
734 case SCTP_CID_INIT_ACK:
735 case SCTP_CID_SHUTDOWN_COMPLETE:
736 sctp_packet_init(&singleton, transport, sport, dport);
737 sctp_packet_config(&singleton, vtag, 0);
738 sctp_packet_append_chunk(&singleton, chunk);
739 error = sctp_packet_transmit(&singleton);
740 if (error < 0)
741 return error;
742 break;
744 case SCTP_CID_ABORT:
745 case SCTP_CID_SACK:
746 case SCTP_CID_HEARTBEAT:
747 case SCTP_CID_HEARTBEAT_ACK:
748 case SCTP_CID_SHUTDOWN:
749 case SCTP_CID_SHUTDOWN_ACK:
750 case SCTP_CID_ERROR:
751 case SCTP_CID_COOKIE_ECHO:
752 case SCTP_CID_COOKIE_ACK:
753 case SCTP_CID_ECN_ECNE:
754 case SCTP_CID_ECN_CWR:
755 case SCTP_CID_ASCONF:
756 case SCTP_CID_ASCONF_ACK:
757 case SCTP_CID_FWD_TSN:
758 sctp_packet_transmit_chunk(packet, chunk);
759 break;
761 default:
762 /* We built a chunk with an illegal type! */
763 BUG();
764 };
765 }
767 /* Is it OK to send data chunks? */
768 switch (asoc->state) {
769 case SCTP_STATE_COOKIE_ECHOED:
770 /* Only allow bundling when this packet has a COOKIE-ECHO
771 * chunk.
772 */
773 if (!packet || !packet->has_cookie_echo)
774 break;
776 /* fallthru */
777 case SCTP_STATE_ESTABLISHED:
778 case SCTP_STATE_SHUTDOWN_PENDING:
779 case SCTP_STATE_SHUTDOWN_RECEIVED:
780 /*
781 * RFC 2960 6.1 Transmission of DATA Chunks
782 *
783 * C) When the time comes for the sender to transmit,
784 * before sending new DATA chunks, the sender MUST
785 * first transmit any outstanding DATA chunks which
786 * are marked for retransmission (limited by the
787 * current cwnd).
788 */
789 if (!list_empty(&q->retransmit)) {
790 if (transport == asoc->peer.retran_path)
791 goto retran;
793 /* Switch transports & prepare the packet. */
795 transport = asoc->peer.retran_path;
797 if (list_empty(&transport->send_ready)) {
798 list_add_tail(&transport->send_ready,
799 &transport_list);
800 }
802 packet = &transport->packet;
803 sctp_packet_config(packet, vtag,
804 asoc->peer.ecn_capable);
805 retran:
806 error = sctp_outq_flush_rtx(q, packet,
807 rtx_timeout, &start_timer);
809 if (start_timer)
810 sctp_transport_reset_timers(transport);
812 /* This can happen on COOKIE-ECHO resend. Only
813 * one chunk can get bundled with a COOKIE-ECHO.
814 */
815 if (packet->has_cookie_echo)
816 goto sctp_flush_out;
818 /* Don't send new data if there is still data
819 * waiting to retransmit.
820 */
821 if (!list_empty(&q->retransmit))
822 goto sctp_flush_out;
823 }
825 /* Finally, transmit new packets. */
826 start_timer = 0;
827 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) {
828 /* RFC 2960 6.5 Every DATA chunk MUST carry a valid
829 * stream identifier.
830 */
831 if (chunk->sinfo.sinfo_stream >=
832 asoc->c.sinit_num_ostreams) {
834 /* Mark as failed send. */
835 sctp_chunk_fail(chunk, SCTP_ERROR_INV_STRM);
836 sctp_chunk_free(chunk);
837 continue;
838 }
840 /* Has this chunk expired? */
841 if (sctp_chunk_abandoned(chunk)) {
842 sctp_chunk_fail(chunk, 0);
843 sctp_chunk_free(chunk);
844 continue;
845 }
847 /* If there is a specified transport, use it.
848 * Otherwise, we want to use the active path.
849 */
850 new_transport = chunk->transport;
851 if (!new_transport ||
852 ((new_transport->state == SCTP_INACTIVE) ||
853 (new_transport->state == SCTP_UNCONFIRMED)))
854 new_transport = asoc->peer.active_path;
856 /* Change packets if necessary. */
857 if (new_transport != transport) {
858 transport = new_transport;
860 /* Schedule to have this transport's
861 * packet flushed.
862 */
863 if (list_empty(&transport->send_ready)) {
864 list_add_tail(&transport->send_ready,
865 &transport_list);
866 }
868 packet = &transport->packet;
869 sctp_packet_config(packet, vtag,
870 asoc->peer.ecn_capable);
871 }
873 SCTP_DEBUG_PRINTK("sctp_outq_flush(%p, %p[%s]), ",
874 q, chunk,
875 chunk && chunk->chunk_hdr ?
876 sctp_cname(SCTP_ST_CHUNK(
877 chunk->chunk_hdr->type))
878 : "Illegal Chunk");
880 SCTP_DEBUG_PRINTK("TX TSN 0x%x skb->head "
881 "%p skb->users %d.\n",
882 ntohl(chunk->subh.data_hdr->tsn),
883 chunk->skb ?chunk->skb->head : NULL,
884 chunk->skb ?
885 atomic_read(&chunk->skb->users) : -1);
887 /* Add the chunk to the packet. */
888 status = sctp_packet_transmit_chunk(packet, chunk);
890 switch (status) {
891 case SCTP_XMIT_PMTU_FULL:
892 case SCTP_XMIT_RWND_FULL:
893 case SCTP_XMIT_NAGLE_DELAY:
894 /* We could not append this chunk, so put
895 * the chunk back on the output queue.
896 */
897 SCTP_DEBUG_PRINTK("sctp_outq_flush: could "
898 "not transmit TSN: 0x%x, status: %d\n",
899 ntohl(chunk->subh.data_hdr->tsn),
900 status);
901 sctp_outq_head_data(q, chunk);
902 goto sctp_flush_out;
903 break;
905 case SCTP_XMIT_OK:
906 break;
908 default:
909 BUG();
910 }
912 /* BUG: We assume that the sctp_packet_transmit()
913 * call below will succeed all the time and add the
914 * chunk to the transmitted list and restart the
915 * timers.
916 * It is possible that the call can fail under OOM
917 * conditions.
918 *
919 * Is this really a problem? Won't this behave
920 * like a lost TSN?
921 */
922 list_add_tail(&chunk->transmitted_list,
923 &transport->transmitted);
925 sctp_transport_reset_timers(transport);
927 q->empty = 0;
929 /* Only let one DATA chunk get bundled with a
930 * COOKIE-ECHO chunk.
931 */
932 if (packet->has_cookie_echo)
933 goto sctp_flush_out;
934 }
935 break;
937 default:
938 /* Do nothing. */
939 break;
940 }
942 sctp_flush_out:
944 /* Before returning, examine all the transports touched in
945 * this call. Right now, we bluntly force clear all the
946 * transports. Things might change after we implement Nagle.
947 * But such an examination is still required.
948 *
949 * --xguo
950 */
951 while ((ltransport = sctp_list_dequeue(&transport_list)) != NULL ) {
952 struct sctp_transport *t = list_entry(ltransport,
953 struct sctp_transport,
954 send_ready);
955 packet = &t->packet;
956 if (!sctp_packet_empty(packet))
957 error = sctp_packet_transmit(packet);
958 }
960 return error;
961 }
963 /* Update unack_data based on the incoming SACK chunk */
964 static void sctp_sack_update_unack_data(struct sctp_association *assoc,
965 struct sctp_sackhdr *sack)
966 {
967 sctp_sack_variable_t *frags;
968 __u16 unack_data;
969 int i;
971 unack_data = assoc->next_tsn - assoc->ctsn_ack_point - 1;
973 frags = sack->variable;
974 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); i++) {
975 unack_data -= ((ntohs(frags[i].gab.end) -
976 ntohs(frags[i].gab.start) + 1));
977 }
979 assoc->unack_data = unack_data;
980 }
982 /* Return the highest new tsn that is acknowledged by the given SACK chunk. */
983 static __u32 sctp_highest_new_tsn(struct sctp_sackhdr *sack,
984 struct sctp_association *asoc)
985 {
986 struct list_head *ltransport, *lchunk;
987 struct sctp_transport *transport;
988 struct sctp_chunk *chunk;
989 __u32 highest_new_tsn, tsn;
990 struct list_head *transport_list = &asoc->peer.transport_addr_list;
992 highest_new_tsn = ntohl(sack->cum_tsn_ack);
994 list_for_each(ltransport, transport_list) {
995 transport = list_entry(ltransport, struct sctp_transport,
996 transports);
997 list_for_each(lchunk, &transport->transmitted) {
998 chunk = list_entry(lchunk, struct sctp_chunk,
999 transmitted_list);
1000 tsn = ntohl(chunk->subh.data_hdr->tsn);
1002 if (!chunk->tsn_gap_acked &&
1003 TSN_lt(highest_new_tsn, tsn) &&
1004 sctp_acked(sack, tsn))
1005 highest_new_tsn = tsn;
1009 return highest_new_tsn;
1012 /* This is where we REALLY process a SACK.
1014 * Process the SACK against the outqueue. Mostly, this just frees
1015 * things off the transmitted queue.
1016 */
1017 int sctp_outq_sack(struct sctp_outq *q, struct sctp_sackhdr *sack)
1019 struct sctp_association *asoc = q->asoc;
1020 struct sctp_transport *transport;
1021 struct sctp_chunk *tchunk = NULL;
1022 struct list_head *lchunk, *transport_list, *pos, *temp;
1023 sctp_sack_variable_t *frags = sack->variable;
1024 __u32 sack_ctsn, ctsn, tsn;
1025 __u32 highest_tsn, highest_new_tsn;
1026 __u32 sack_a_rwnd;
1027 unsigned outstanding;
1028 struct sctp_transport *primary = asoc->peer.primary_path;
1029 int count_of_newacks = 0;
1031 /* Grab the association's destination address list. */
1032 transport_list = &asoc->peer.transport_addr_list;
1034 sack_ctsn = ntohl(sack->cum_tsn_ack);
1036 /*
1037 * SFR-CACC algorithm:
1038 * On receipt of a SACK the sender SHOULD execute the
1039 * following statements.
1041 * 1) If the cumulative ack in the SACK passes next tsn_at_change
1042 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be
1043 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for
1044 * all destinations.
1045 */
1046 if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) {
1047 primary->cacc.changeover_active = 0;
1048 list_for_each(pos, transport_list) {
1049 transport = list_entry(pos, struct sctp_transport,
1050 transports);
1051 transport->cacc.cycling_changeover = 0;
1055 /*
1056 * SFR-CACC algorithm:
1057 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE
1058 * is set the receiver of the SACK MUST take the following actions:
1060 * A) Initialize the cacc_saw_newack to 0 for all destination
1061 * addresses.
1062 */
1063 if (sack->num_gap_ack_blocks > 0 &&
1064 primary->cacc.changeover_active) {
1065 list_for_each(pos, transport_list) {
1066 transport = list_entry(pos, struct sctp_transport,
1067 transports);
1068 transport->cacc.cacc_saw_newack = 0;
1072 /* Get the highest TSN in the sack. */
1073 highest_tsn = sack_ctsn;
1074 if (sack->num_gap_ack_blocks)
1075 highest_tsn +=
1076 ntohs(frags[ntohs(sack->num_gap_ack_blocks) - 1].gab.end);
1078 if (TSN_lt(asoc->highest_sacked, highest_tsn)) {
1079 highest_new_tsn = highest_tsn;
1080 asoc->highest_sacked = highest_tsn;
1081 } else {
1082 highest_new_tsn = sctp_highest_new_tsn(sack, asoc);
1085 /* Run through the retransmit queue. Credit bytes received
1086 * and free those chunks that we can.
1087 */
1088 sctp_check_transmitted(q, &q->retransmit, NULL, sack, highest_new_tsn);
1089 sctp_mark_missing(q, &q->retransmit, NULL, highest_new_tsn, 0);
1091 /* Run through the transmitted queue.
1092 * Credit bytes received and free those chunks which we can.
1094 * This is a MASSIVE candidate for optimization.
1095 */
1096 list_for_each(pos, transport_list) {
1097 transport = list_entry(pos, struct sctp_transport,
1098 transports);
1099 sctp_check_transmitted(q, &transport->transmitted,
1100 transport, sack, highest_new_tsn);
1101 /*
1102 * SFR-CACC algorithm:
1103 * C) Let count_of_newacks be the number of
1104 * destinations for which cacc_saw_newack is set.
1105 */
1106 if (transport->cacc.cacc_saw_newack)
1107 count_of_newacks ++;
1110 list_for_each(pos, transport_list) {
1111 transport = list_entry(pos, struct sctp_transport,
1112 transports);
1113 sctp_mark_missing(q, &transport->transmitted, transport,
1114 highest_new_tsn, count_of_newacks);
1117 /* Move the Cumulative TSN Ack Point if appropriate. */
1118 if (TSN_lt(asoc->ctsn_ack_point, sack_ctsn))
1119 asoc->ctsn_ack_point = sack_ctsn;
1121 /* Update unack_data field in the assoc. */
1122 sctp_sack_update_unack_data(asoc, sack);
1124 ctsn = asoc->ctsn_ack_point;
1126 /* Throw away stuff rotting on the sack queue. */
1127 list_for_each_safe(lchunk, temp, &q->sacked) {
1128 tchunk = list_entry(lchunk, struct sctp_chunk,
1129 transmitted_list);
1130 tsn = ntohl(tchunk->subh.data_hdr->tsn);
1131 if (TSN_lte(tsn, ctsn))
1132 sctp_chunk_free(tchunk);
1135 /* ii) Set rwnd equal to the newly received a_rwnd minus the
1136 * number of bytes still outstanding after processing the
1137 * Cumulative TSN Ack and the Gap Ack Blocks.
1138 */
1140 sack_a_rwnd = ntohl(sack->a_rwnd);
1141 outstanding = q->outstanding_bytes;
1143 if (outstanding < sack_a_rwnd)
1144 sack_a_rwnd -= outstanding;
1145 else
1146 sack_a_rwnd = 0;
1148 asoc->peer.rwnd = sack_a_rwnd;
1150 sctp_generate_fwdtsn(q, sack_ctsn);
1152 SCTP_DEBUG_PRINTK("%s: sack Cumulative TSN Ack is 0x%x.\n",
1153 __FUNCTION__, sack_ctsn);
1154 SCTP_DEBUG_PRINTK("%s: Cumulative TSN Ack of association, "
1155 "%p is 0x%x. Adv peer ack point: 0x%x\n",
1156 __FUNCTION__, asoc, ctsn, asoc->adv_peer_ack_point);
1158 /* See if all chunks are acked.
1159 * Make sure the empty queue handler will get run later.
1160 */
1161 q->empty = (list_empty(&q->out_chunk_list) &&
1162 list_empty(&q->control_chunk_list) &&
1163 list_empty(&q->retransmit));
1164 if (!q->empty)
1165 goto finish;
1167 list_for_each(pos, transport_list) {
1168 transport = list_entry(pos, struct sctp_transport,
1169 transports);
1170 q->empty = q->empty && list_empty(&transport->transmitted);
1171 if (!q->empty)
1172 goto finish;
1175 SCTP_DEBUG_PRINTK("sack queue is empty.\n");
1176 finish:
1177 return q->empty;
1180 /* Is the outqueue empty? */
1181 int sctp_outq_is_empty(const struct sctp_outq *q)
1183 return q->empty;
1186 /********************************************************************
1187 * 2nd Level Abstractions
1188 ********************************************************************/
1190 /* Go through a transport's transmitted list or the association's retransmit
1191 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked.
1192 * The retransmit list will not have an associated transport.
1194 * I added coherent debug information output. --xguo
1196 * Instead of printing 'sacked' or 'kept' for each TSN on the
1197 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5.
1198 * KEPT TSN6-TSN7, etc.
1199 */
1200 static void sctp_check_transmitted(struct sctp_outq *q,
1201 struct list_head *transmitted_queue,
1202 struct sctp_transport *transport,
1203 struct sctp_sackhdr *sack,
1204 __u32 highest_new_tsn_in_sack)
1206 struct list_head *lchunk;
1207 struct sctp_chunk *tchunk;
1208 struct list_head tlist;
1209 __u32 tsn;
1210 __u32 sack_ctsn;
1211 __u32 rtt;
1212 __u8 restart_timer = 0;
1213 int bytes_acked = 0;
1215 /* These state variables are for coherent debug output. --xguo */
1217 #if SCTP_DEBUG
1218 __u32 dbg_ack_tsn = 0; /* An ACKed TSN range starts here... */
1219 __u32 dbg_last_ack_tsn = 0; /* ...and finishes here. */
1220 __u32 dbg_kept_tsn = 0; /* An un-ACKed range starts here... */
1221 __u32 dbg_last_kept_tsn = 0; /* ...and finishes here. */
1223 /* 0 : The last TSN was ACKed.
1224 * 1 : The last TSN was NOT ACKed (i.e. KEPT).
1225 * -1: We need to initialize.
1226 */
1227 int dbg_prt_state = -1;
1228 #endif /* SCTP_DEBUG */
1230 sack_ctsn = ntohl(sack->cum_tsn_ack);
1232 INIT_LIST_HEAD(&tlist);
1234 /* The while loop will skip empty transmitted queues. */
1235 while (NULL != (lchunk = sctp_list_dequeue(transmitted_queue))) {
1236 tchunk = list_entry(lchunk, struct sctp_chunk,
1237 transmitted_list);
1239 if (sctp_chunk_abandoned(tchunk)) {
1240 /* Move the chunk to abandoned list. */
1241 sctp_insert_list(&q->abandoned, lchunk);
1242 continue;
1245 tsn = ntohl(tchunk->subh.data_hdr->tsn);
1246 if (sctp_acked(sack, tsn)) {
1247 /* If this queue is the retransmit queue, the
1248 * retransmit timer has already reclaimed
1249 * the outstanding bytes for this chunk, so only
1250 * count bytes associated with a transport.
1251 */
1252 if (transport) {
1253 /* If this chunk is being used for RTT
1254 * measurement, calculate the RTT and update
1255 * the RTO using this value.
1257 * 6.3.1 C5) Karn's algorithm: RTT measurements
1258 * MUST NOT be made using packets that were
1259 * retransmitted (and thus for which it is
1260 * ambiguous whether the reply was for the
1261 * first instance of the packet or a later
1262 * instance).
1263 */
1264 if (!tchunk->tsn_gap_acked &&
1265 !tchunk->resent &&
1266 tchunk->rtt_in_progress) {
1267 tchunk->rtt_in_progress = 0;
1268 rtt = jiffies - tchunk->sent_at;
1269 sctp_transport_update_rto(transport,
1270 rtt);
1273 if (TSN_lte(tsn, sack_ctsn)) {
1274 /* RFC 2960 6.3.2 Retransmission Timer Rules
1276 * R3) Whenever a SACK is received
1277 * that acknowledges the DATA chunk
1278 * with the earliest outstanding TSN
1279 * for that address, restart T3-rtx
1280 * timer for that address with its
1281 * current RTO.
1282 */
1283 restart_timer = 1;
1285 if (!tchunk->tsn_gap_acked) {
1286 tchunk->tsn_gap_acked = 1;
1287 bytes_acked += sctp_data_size(tchunk);
1288 /*
1289 * SFR-CACC algorithm:
1290 * 2) If the SACK contains gap acks
1291 * and the flag CHANGEOVER_ACTIVE is
1292 * set the receiver of the SACK MUST
1293 * take the following action:
1295 * B) For each TSN t being acked that
1296 * has not been acked in any SACK so
1297 * far, set cacc_saw_newack to 1 for
1298 * the destination that the TSN was
1299 * sent to.
1300 */
1301 if (transport &&
1302 sack->num_gap_ack_blocks &&
1303 q->asoc->peer.primary_path->cacc.
1304 changeover_active)
1305 transport->cacc.cacc_saw_newack
1306 = 1;
1309 list_add_tail(&tchunk->transmitted_list,
1310 &q->sacked);
1311 } else {
1312 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2
1313 * M2) Each time a SACK arrives reporting
1314 * 'Stray DATA chunk(s)' record the highest TSN
1315 * reported as newly acknowledged, call this
1316 * value 'HighestTSNinSack'. A newly
1317 * acknowledged DATA chunk is one not
1318 * previously acknowledged in a SACK.
1320 * When the SCTP sender of data receives a SACK
1321 * chunk that acknowledges, for the first time,
1322 * the receipt of a DATA chunk, all the still
1323 * unacknowledged DATA chunks whose TSN is
1324 * older than that newly acknowledged DATA
1325 * chunk, are qualified as 'Stray DATA chunks'.
1326 */
1327 if (!tchunk->tsn_gap_acked) {
1328 tchunk->tsn_gap_acked = 1;
1329 bytes_acked += sctp_data_size(tchunk);
1331 list_add_tail(lchunk, &tlist);
1334 #if SCTP_DEBUG
1335 switch (dbg_prt_state) {
1336 case 0: /* last TSN was ACKed */
1337 if (dbg_last_ack_tsn + 1 == tsn) {
1338 /* This TSN belongs to the
1339 * current ACK range.
1340 */
1341 break;
1344 if (dbg_last_ack_tsn != dbg_ack_tsn) {
1345 /* Display the end of the
1346 * current range.
1347 */
1348 SCTP_DEBUG_PRINTK("-%08x",
1349 dbg_last_ack_tsn);
1352 /* Start a new range. */
1353 SCTP_DEBUG_PRINTK(",%08x", tsn);
1354 dbg_ack_tsn = tsn;
1355 break;
1357 case 1: /* The last TSN was NOT ACKed. */
1358 if (dbg_last_kept_tsn != dbg_kept_tsn) {
1359 /* Display the end of current range. */
1360 SCTP_DEBUG_PRINTK("-%08x",
1361 dbg_last_kept_tsn);
1364 SCTP_DEBUG_PRINTK("\n");
1366 /* FALL THROUGH... */
1367 default:
1368 /* This is the first-ever TSN we examined. */
1369 /* Start a new range of ACK-ed TSNs. */
1370 SCTP_DEBUG_PRINTK("ACKed: %08x", tsn);
1371 dbg_prt_state = 0;
1372 dbg_ack_tsn = tsn;
1373 };
1375 dbg_last_ack_tsn = tsn;
1376 #endif /* SCTP_DEBUG */
1378 } else {
1379 if (tchunk->tsn_gap_acked) {
1380 SCTP_DEBUG_PRINTK("%s: Receiver reneged on "
1381 "data TSN: 0x%x\n",
1382 __FUNCTION__,
1383 tsn);
1384 tchunk->tsn_gap_acked = 0;
1386 bytes_acked -= sctp_data_size(tchunk);
1388 /* RFC 2960 6.3.2 Retransmission Timer Rules
1390 * R4) Whenever a SACK is received missing a
1391 * TSN that was previously acknowledged via a
1392 * Gap Ack Block, start T3-rtx for the
1393 * destination address to which the DATA
1394 * chunk was originally
1395 * transmitted if it is not already running.
1396 */
1397 restart_timer = 1;
1400 list_add_tail(lchunk, &tlist);
1402 #if SCTP_DEBUG
1403 /* See the above comments on ACK-ed TSNs. */
1404 switch (dbg_prt_state) {
1405 case 1:
1406 if (dbg_last_kept_tsn + 1 == tsn)
1407 break;
1409 if (dbg_last_kept_tsn != dbg_kept_tsn)
1410 SCTP_DEBUG_PRINTK("-%08x",
1411 dbg_last_kept_tsn);
1413 SCTP_DEBUG_PRINTK(",%08x", tsn);
1414 dbg_kept_tsn = tsn;
1415 break;
1417 case 0:
1418 if (dbg_last_ack_tsn != dbg_ack_tsn)
1419 SCTP_DEBUG_PRINTK("-%08x",
1420 dbg_last_ack_tsn);
1421 SCTP_DEBUG_PRINTK("\n");
1423 /* FALL THROUGH... */
1424 default:
1425 SCTP_DEBUG_PRINTK("KEPT: %08x",tsn);
1426 dbg_prt_state = 1;
1427 dbg_kept_tsn = tsn;
1428 };
1430 dbg_last_kept_tsn = tsn;
1431 #endif /* SCTP_DEBUG */
1435 #if SCTP_DEBUG
1436 /* Finish off the last range, displaying its ending TSN. */
1437 switch (dbg_prt_state) {
1438 case 0:
1439 if (dbg_last_ack_tsn != dbg_ack_tsn) {
1440 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_ack_tsn);
1441 } else {
1442 SCTP_DEBUG_PRINTK("\n");
1444 break;
1446 case 1:
1447 if (dbg_last_kept_tsn != dbg_kept_tsn) {
1448 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_kept_tsn);
1449 } else {
1450 SCTP_DEBUG_PRINTK("\n");
1452 };
1453 #endif /* SCTP_DEBUG */
1454 if (transport) {
1455 if (bytes_acked) {
1456 /* 8.2. When an outstanding TSN is acknowledged,
1457 * the endpoint shall clear the error counter of
1458 * the destination transport address to which the
1459 * DATA chunk was last sent.
1460 * The association's overall error counter is
1461 * also cleared.
1462 */
1463 transport->error_count = 0;
1464 transport->asoc->overall_error_count = 0;
1466 /* Mark the destination transport address as
1467 * active if it is not so marked.
1468 */
1469 if ((transport->state == SCTP_INACTIVE) ||
1470 (transport->state == SCTP_UNCONFIRMED)) {
1471 sctp_assoc_control_transport(
1472 transport->asoc,
1473 transport,
1474 SCTP_TRANSPORT_UP,
1475 SCTP_RECEIVED_SACK);
1478 sctp_transport_raise_cwnd(transport, sack_ctsn,
1479 bytes_acked);
1481 transport->flight_size -= bytes_acked;
1482 q->outstanding_bytes -= bytes_acked;
1483 } else {
1484 /* RFC 2960 6.1, sctpimpguide-06 2.15.2
1485 * When a sender is doing zero window probing, it
1486 * should not timeout the association if it continues
1487 * to receive new packets from the receiver. The
1488 * reason is that the receiver MAY keep its window
1489 * closed for an indefinite time.
1490 * A sender is doing zero window probing when the
1491 * receiver's advertised window is zero, and there is
1492 * only one data chunk in flight to the receiver.
1493 */
1494 if (!q->asoc->peer.rwnd &&
1495 !list_empty(&tlist) &&
1496 (sack_ctsn+2 == q->asoc->next_tsn)) {
1497 SCTP_DEBUG_PRINTK("%s: SACK received for zero "
1498 "window probe: %u\n",
1499 __FUNCTION__, sack_ctsn);
1500 q->asoc->overall_error_count = 0;
1501 transport->error_count = 0;
1505 /* RFC 2960 6.3.2 Retransmission Timer Rules
1507 * R2) Whenever all outstanding data sent to an address have
1508 * been acknowledged, turn off the T3-rtx timer of that
1509 * address.
1510 */
1511 if (!transport->flight_size) {
1512 if (timer_pending(&transport->T3_rtx_timer) &&
1513 del_timer(&transport->T3_rtx_timer)) {
1514 sctp_transport_put(transport);
1516 } else if (restart_timer) {
1517 if (!mod_timer(&transport->T3_rtx_timer,
1518 jiffies + transport->rto))
1519 sctp_transport_hold(transport);
1523 list_splice(&tlist, transmitted_queue);
1526 /* Mark chunks as missing and consequently may get retransmitted. */
1527 static void sctp_mark_missing(struct sctp_outq *q,
1528 struct list_head *transmitted_queue,
1529 struct sctp_transport *transport,
1530 __u32 highest_new_tsn_in_sack,
1531 int count_of_newacks)
1533 struct sctp_chunk *chunk;
1534 struct list_head *pos;
1535 __u32 tsn;
1536 char do_fast_retransmit = 0;
1537 struct sctp_transport *primary = q->asoc->peer.primary_path;
1539 list_for_each(pos, transmitted_queue) {
1541 chunk = list_entry(pos, struct sctp_chunk, transmitted_list);
1542 tsn = ntohl(chunk->subh.data_hdr->tsn);
1544 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all
1545 * 'Unacknowledged TSN's', if the TSN number of an
1546 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack'
1547 * value, increment the 'TSN.Missing.Report' count on that
1548 * chunk if it has NOT been fast retransmitted or marked for
1549 * fast retransmit already.
1550 */
1551 if (!chunk->fast_retransmit &&
1552 !chunk->tsn_gap_acked &&
1553 TSN_lt(tsn, highest_new_tsn_in_sack)) {
1555 /* SFR-CACC may require us to skip marking
1556 * this chunk as missing.
1557 */
1558 if (!transport || !sctp_cacc_skip(primary, transport,
1559 count_of_newacks, tsn)) {
1560 chunk->tsn_missing_report++;
1562 SCTP_DEBUG_PRINTK(
1563 "%s: TSN 0x%x missing counter: %d\n",
1564 __FUNCTION__, tsn,
1565 chunk->tsn_missing_report);
1568 /*
1569 * M4) If any DATA chunk is found to have a
1570 * 'TSN.Missing.Report'
1571 * value larger than or equal to 3, mark that chunk for
1572 * retransmission and start the fast retransmit procedure.
1573 */
1575 if (chunk->tsn_missing_report >= 3) {
1576 chunk->fast_retransmit = 1;
1577 do_fast_retransmit = 1;
1581 if (transport) {
1582 if (do_fast_retransmit)
1583 sctp_retransmit(q, transport, SCTP_RTXR_FAST_RTX);
1585 SCTP_DEBUG_PRINTK("%s: transport: %p, cwnd: %d, "
1586 "ssthresh: %d, flight_size: %d, pba: %d\n",
1587 __FUNCTION__, transport, transport->cwnd,
1588 transport->ssthresh, transport->flight_size,
1589 transport->partial_bytes_acked);
1593 /* Is the given TSN acked by this packet? */
1594 static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn)
1596 int i;
1597 sctp_sack_variable_t *frags;
1598 __u16 gap;
1599 __u32 ctsn = ntohl(sack->cum_tsn_ack);
1601 if (TSN_lte(tsn, ctsn))
1602 goto pass;
1604 /* 3.3.4 Selective Acknowledgement (SACK) (3):
1606 * Gap Ack Blocks:
1607 * These fields contain the Gap Ack Blocks. They are repeated
1608 * for each Gap Ack Block up to the number of Gap Ack Blocks
1609 * defined in the Number of Gap Ack Blocks field. All DATA
1610 * chunks with TSNs greater than or equal to (Cumulative TSN
1611 * Ack + Gap Ack Block Start) and less than or equal to
1612 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack
1613 * Block are assumed to have been received correctly.
1614 */
1616 frags = sack->variable;
1617 gap = tsn - ctsn;
1618 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); ++i) {
1619 if (TSN_lte(ntohs(frags[i].gab.start), gap) &&
1620 TSN_lte(gap, ntohs(frags[i].gab.end)))
1621 goto pass;
1624 return 0;
1625 pass:
1626 return 1;
1629 static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip *skiplist,
1630 int nskips, __u16 stream)
1632 int i;
1634 for (i = 0; i < nskips; i++) {
1635 if (skiplist[i].stream == stream)
1636 return i;
1638 return i;
1641 /* Create and add a fwdtsn chunk to the outq's control queue if needed. */
1642 static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 ctsn)
1644 struct sctp_association *asoc = q->asoc;
1645 struct sctp_chunk *ftsn_chunk = NULL;
1646 struct sctp_fwdtsn_skip ftsn_skip_arr[10];
1647 int nskips = 0;
1648 int skip_pos = 0;
1649 __u32 tsn;
1650 struct sctp_chunk *chunk;
1651 struct list_head *lchunk, *temp;
1653 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the
1654 * received SACK.
1656 * If (Advanced.Peer.Ack.Point < SackCumAck), then update
1657 * Advanced.Peer.Ack.Point to be equal to SackCumAck.
1658 */
1659 if (TSN_lt(asoc->adv_peer_ack_point, ctsn))
1660 asoc->adv_peer_ack_point = ctsn;
1662 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point"
1663 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as
1664 * the chunk next in the out-queue space is marked as "abandoned" as
1665 * shown in the following example:
1667 * Assuming that a SACK arrived with the Cumulative TSN ACK 102
1668 * and the Advanced.Peer.Ack.Point is updated to this value:
1670 * out-queue at the end of ==> out-queue after Adv.Ack.Point
1671 * normal SACK processing local advancement
1672 * ... ...
1673 * Adv.Ack.Pt-> 102 acked 102 acked
1674 * 103 abandoned 103 abandoned
1675 * 104 abandoned Adv.Ack.P-> 104 abandoned
1676 * 105 105
1677 * 106 acked 106 acked
1678 * ... ...
1680 * In this example, the data sender successfully advanced the
1681 * "Advanced.Peer.Ack.Point" from 102 to 104 locally.
1682 */
1683 list_for_each_safe(lchunk, temp, &q->abandoned) {
1684 chunk = list_entry(lchunk, struct sctp_chunk,
1685 transmitted_list);
1686 tsn = ntohl(chunk->subh.data_hdr->tsn);
1688 /* Remove any chunks in the abandoned queue that are acked by
1689 * the ctsn.
1690 */
1691 if (TSN_lte(tsn, ctsn)) {
1692 list_del_init(lchunk);
1693 if (!chunk->tsn_gap_acked) {
1694 chunk->transport->flight_size -=
1695 sctp_data_size(chunk);
1696 q->outstanding_bytes -= sctp_data_size(chunk);
1698 sctp_chunk_free(chunk);
1699 } else {
1700 if (TSN_lte(tsn, asoc->adv_peer_ack_point+1)) {
1701 asoc->adv_peer_ack_point = tsn;
1702 if (chunk->chunk_hdr->flags &
1703 SCTP_DATA_UNORDERED)
1704 continue;
1705 skip_pos = sctp_get_skip_pos(&ftsn_skip_arr[0],
1706 nskips,
1707 chunk->subh.data_hdr->stream);
1708 ftsn_skip_arr[skip_pos].stream =
1709 chunk->subh.data_hdr->stream;
1710 ftsn_skip_arr[skip_pos].ssn =
1711 chunk->subh.data_hdr->ssn;
1712 if (skip_pos == nskips)
1713 nskips++;
1714 if (nskips == 10)
1715 break;
1716 } else
1717 break;
1721 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point"
1722 * is greater than the Cumulative TSN ACK carried in the received
1723 * SACK, the data sender MUST send the data receiver a FORWARD TSN
1724 * chunk containing the latest value of the
1725 * "Advanced.Peer.Ack.Point".
1727 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD
1728 * list each stream and sequence number in the forwarded TSN. This
1729 * information will enable the receiver to easily find any
1730 * stranded TSN's waiting on stream reorder queues. Each stream
1731 * SHOULD only be reported once; this means that if multiple
1732 * abandoned messages occur in the same stream then only the
1733 * highest abandoned stream sequence number is reported. If the
1734 * total size of the FORWARD TSN does NOT fit in a single MTU then
1735 * the sender of the FORWARD TSN SHOULD lower the
1736 * Advanced.Peer.Ack.Point to the last TSN that will fit in a
1737 * single MTU.
1738 */
1739 if (asoc->adv_peer_ack_point > ctsn)
1740 ftsn_chunk = sctp_make_fwdtsn(asoc, asoc->adv_peer_ack_point,
1741 nskips, &ftsn_skip_arr[0]);
1743 if (ftsn_chunk) {
1744 list_add_tail(&ftsn_chunk->list, &q->control_chunk_list);
1745 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);