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[linux-2.6/sactl.git] / net / sctp / outqueue.c
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1 /* SCTP kernel implementation
2 * (C) Copyright IBM Corp. 2001, 2004
3 * Copyright (c) 1999-2000 Cisco, Inc.
4 * Copyright (c) 1999-2001 Motorola, Inc.
5 * Copyright (c) 2001-2003 Intel Corp.
7 * This file is part of the SCTP kernel implementation
9 * These functions implement the sctp_outq class. The outqueue handles
10 * bundling and queueing of outgoing SCTP chunks.
12 * This SCTP implementation is free software;
13 * you can redistribute it and/or modify it under the terms of
14 * the GNU General Public License as published by
15 * the Free Software Foundation; either version 2, or (at your option)
16 * any later version.
18 * This SCTP implementation is distributed in the hope that it
19 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
20 * ************************
21 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
22 * See the GNU General Public License for more details.
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.
29 * Please send any bug reports or fixes you make to the
30 * email address(es):
31 * lksctp developers <lksctp-developers@lists.sourceforge.net>
33 * Or submit a bug report through the following website:
34 * http://www.sf.net/projects/lksctp
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>
45 * Any bugs reported given to us we will try to fix... any fixes shared will
46 * be incorporated into the next SCTP release.
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)
78 list_add(&ch->list, &q->out_chunk_list);
79 q->out_qlen += ch->skb->len;
80 return;
83 /* Take data from the front of the queue. */
84 static inline struct sctp_chunk *sctp_outq_dequeue_data(struct sctp_outq *q)
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;
95 return ch;
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)
101 list_add_tail(&ch->list, &q->out_chunk_list);
102 q->out_qlen += ch->skb->len;
103 return;
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.
112 static inline int sctp_cacc_skip_3_1_d(struct sctp_transport *primary,
113 struct sctp_transport *transport,
114 int count_of_newacks)
116 if (count_of_newacks >=2 && transport != primary)
117 return 1;
118 return 0;
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.
128 static inline int sctp_cacc_skip_3_1_f(struct sctp_transport *transport,
129 int count_of_newacks)
131 if (count_of_newacks < 2 && !transport->cacc.cacc_saw_newack)
132 return 1;
133 return 0;
137 * SFR-CACC algorithm:
138 * 3.1) If CYCLING_CHANGEOVER is 0, the sender SHOULD
139 * execute steps C, D, F.
141 * C has been implemented in sctp_outq_sack
143 static inline int sctp_cacc_skip_3_1(struct sctp_transport *primary,
144 struct sctp_transport *transport,
145 int count_of_newacks)
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;
154 return 0;
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.
164 static inline int sctp_cacc_skip_3_2(struct sctp_transport *primary, __u32 tsn)
166 if (primary->cacc.cycling_changeover &&
167 TSN_lt(tsn, primary->cacc.next_tsn_at_change))
168 return 1;
169 return 0;
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.
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]).
186 static inline int sctp_cacc_skip(struct sctp_transport *primary,
187 struct sctp_transport *transport,
188 int count_of_newacks,
189 __u32 tsn)
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;
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...
202 void sctp_outq_init(struct sctp_association *asoc, struct sctp_outq *q)
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;
219 /* Free the outqueue structure and any related pending chunks.
221 void sctp_outq_teardown(struct sctp_outq *q)
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);
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);
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);
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);
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);
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);
283 /* Free the outqueue structure and any related pending chunks. */
284 void sctp_outq_free(struct sctp_outq *q)
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);
294 /* Put a new chunk in an sctp_outq. */
295 int sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk)
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.
307 if (SCTP_CID_DATA == chunk->chunk_hdr->type) {
308 /* Is it OK to queue data chunks? */
309 /* From 9. Termination of Association
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.
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;
342 } else {
343 list_add_tail(&chunk->list, &q->control_chunk_list);
344 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
347 if (error < 0)
348 return error;
350 if (!q->cork)
351 error = sctp_outq_flush(q, 0);
353 return error;
356 /* Insert a chunk into the sorted list based on the TSNs. The retransmit list
357 * and the abandoned list are in ascending order.
359 static void sctp_insert_list(struct list_head *head, struct list_head *new)
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;
378 if (!done)
379 list_add_tail(new, head);
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 reason)
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);
400 /* If this chunk has not been previousely acked,
401 * stop considering it 'outstanding'. Our peer
402 * will most likely never see it since it will
403 * not be retransmitted
405 if (!chunk->tsn_gap_acked) {
406 chunk->transport->flight_size -=
407 sctp_data_size(chunk);
408 q->outstanding_bytes -= sctp_data_size(chunk);
409 q->asoc->peer.rwnd += (sctp_data_size(chunk) +
410 sizeof(struct sk_buff));
412 continue;
415 /* If we are doing retransmission due to a timeout or pmtu
416 * discovery, only the chunks that are not yet acked should
417 * be added to the retransmit queue.
419 if ((reason == SCTP_RTXR_FAST_RTX &&
420 (chunk->fast_retransmit > 0)) ||
421 (reason != SCTP_RTXR_FAST_RTX && !chunk->tsn_gap_acked)) {
422 /* If this chunk was sent less then 1 rto ago, do not
423 * retransmit this chunk, but give the peer time
424 * to acknowlege it. Do this only when
425 * retransmitting due to T3 timeout.
427 if (reason == SCTP_RTXR_T3_RTX &&
428 (jiffies - chunk->sent_at) < transport->last_rto)
429 continue;
431 /* RFC 2960 6.2.1 Processing a Received SACK
433 * C) Any time a DATA chunk is marked for
434 * retransmission (via either T3-rtx timer expiration
435 * (Section 6.3.3) or via fast retransmit
436 * (Section 7.2.4)), add the data size of those
437 * chunks to the rwnd.
439 q->asoc->peer.rwnd += (sctp_data_size(chunk) +
440 sizeof(struct sk_buff));
441 q->outstanding_bytes -= sctp_data_size(chunk);
442 transport->flight_size -= sctp_data_size(chunk);
444 /* sctpimpguide-05 Section 2.8.2
445 * M5) If a T3-rtx timer expires, the
446 * 'TSN.Missing.Report' of all affected TSNs is set
447 * to 0.
449 chunk->tsn_missing_report = 0;
451 /* If a chunk that is being used for RTT measurement
452 * has to be retransmitted, we cannot use this chunk
453 * anymore for RTT measurements. Reset rto_pending so
454 * that a new RTT measurement is started when a new
455 * data chunk is sent.
457 if (chunk->rtt_in_progress) {
458 chunk->rtt_in_progress = 0;
459 transport->rto_pending = 0;
462 /* Move the chunk to the retransmit queue. The chunks
463 * on the retransmit queue are always kept in order.
465 list_del_init(lchunk);
466 sctp_insert_list(&q->retransmit, lchunk);
470 SCTP_DEBUG_PRINTK("%s: transport: %p, reason: %d, "
471 "cwnd: %d, ssthresh: %d, flight_size: %d, "
472 "pba: %d\n", __func__,
473 transport, reason,
474 transport->cwnd, transport->ssthresh,
475 transport->flight_size,
476 transport->partial_bytes_acked);
480 /* Mark all the eligible packets on a transport for retransmission and force
481 * one packet out.
483 void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
484 sctp_retransmit_reason_t reason)
486 int error = 0;
488 switch(reason) {
489 case SCTP_RTXR_T3_RTX:
490 SCTP_INC_STATS(SCTP_MIB_T3_RETRANSMITS);
491 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_T3_RTX);
492 /* Update the retran path if the T3-rtx timer has expired for
493 * the current retran path.
495 if (transport == transport->asoc->peer.retran_path)
496 sctp_assoc_update_retran_path(transport->asoc);
497 transport->asoc->rtx_data_chunks +=
498 transport->asoc->unack_data;
499 break;
500 case SCTP_RTXR_FAST_RTX:
501 SCTP_INC_STATS(SCTP_MIB_FAST_RETRANSMITS);
502 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_FAST_RTX);
503 break;
504 case SCTP_RTXR_PMTUD:
505 SCTP_INC_STATS(SCTP_MIB_PMTUD_RETRANSMITS);
506 break;
507 case SCTP_RTXR_T1_RTX:
508 SCTP_INC_STATS(SCTP_MIB_T1_RETRANSMITS);
509 transport->asoc->init_retries++;
510 break;
511 default:
512 BUG();
515 sctp_retransmit_mark(q, transport, reason);
517 /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination,
518 * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by
519 * following the procedures outlined in C1 - C5.
521 sctp_generate_fwdtsn(q, q->asoc->ctsn_ack_point);
523 error = sctp_outq_flush(q, /* rtx_timeout */ 1);
525 if (error)
526 q->asoc->base.sk->sk_err = -error;
530 * Transmit DATA chunks on the retransmit queue. Upon return from
531 * sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which
532 * need to be transmitted by the caller.
533 * We assume that pkt->transport has already been set.
535 * The return value is a normal kernel error return value.
537 static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
538 int rtx_timeout, int *start_timer)
540 struct list_head *lqueue;
541 struct list_head *lchunk, *lchunk1;
542 struct sctp_transport *transport = pkt->transport;
543 sctp_xmit_t status;
544 struct sctp_chunk *chunk, *chunk1;
545 struct sctp_association *asoc;
546 int error = 0;
548 asoc = q->asoc;
549 lqueue = &q->retransmit;
551 /* RFC 2960 6.3.3 Handle T3-rtx Expiration
553 * E3) Determine how many of the earliest (i.e., lowest TSN)
554 * outstanding DATA chunks for the address for which the
555 * T3-rtx has expired will fit into a single packet, subject
556 * to the MTU constraint for the path corresponding to the
557 * destination transport address to which the retransmission
558 * is being sent (this may be different from the address for
559 * which the timer expires [see Section 6.4]). Call this value
560 * K. Bundle and retransmit those K DATA chunks in a single
561 * packet to the destination endpoint.
563 * [Just to be painfully clear, if we are retransmitting
564 * because a timeout just happened, we should send only ONE
565 * packet of retransmitted data.]
567 lchunk = sctp_list_dequeue(lqueue);
569 while (lchunk) {
570 chunk = list_entry(lchunk, struct sctp_chunk,
571 transmitted_list);
573 /* Make sure that Gap Acked TSNs are not retransmitted. A
574 * simple approach is just to move such TSNs out of the
575 * way and into a 'transmitted' queue and skip to the
576 * next chunk.
578 if (chunk->tsn_gap_acked) {
579 list_add_tail(lchunk, &transport->transmitted);
580 lchunk = sctp_list_dequeue(lqueue);
581 continue;
584 /* Attempt to append this chunk to the packet. */
585 status = sctp_packet_append_chunk(pkt, chunk);
587 switch (status) {
588 case SCTP_XMIT_PMTU_FULL:
589 /* Send this packet. */
590 if ((error = sctp_packet_transmit(pkt)) == 0)
591 *start_timer = 1;
593 /* If we are retransmitting, we should only
594 * send a single packet.
596 if (rtx_timeout) {
597 list_add(lchunk, lqueue);
598 lchunk = NULL;
601 /* Bundle lchunk in the next round. */
602 break;
604 case SCTP_XMIT_RWND_FULL:
605 /* Send this packet. */
606 if ((error = sctp_packet_transmit(pkt)) == 0)
607 *start_timer = 1;
609 /* Stop sending DATA as there is no more room
610 * at the receiver.
612 list_add(lchunk, lqueue);
613 lchunk = NULL;
614 break;
616 case SCTP_XMIT_NAGLE_DELAY:
617 /* Send this packet. */
618 if ((error = sctp_packet_transmit(pkt)) == 0)
619 *start_timer = 1;
621 /* Stop sending DATA because of nagle delay. */
622 list_add(lchunk, lqueue);
623 lchunk = NULL;
624 break;
626 default:
627 /* The append was successful, so add this chunk to
628 * the transmitted list.
630 list_add_tail(lchunk, &transport->transmitted);
632 /* Mark the chunk as ineligible for fast retransmit
633 * after it is retransmitted.
635 if (chunk->fast_retransmit > 0)
636 chunk->fast_retransmit = -1;
638 *start_timer = 1;
639 q->empty = 0;
641 /* Retrieve a new chunk to bundle. */
642 lchunk = sctp_list_dequeue(lqueue);
643 break;
646 /* If we are here due to a retransmit timeout or a fast
647 * retransmit and if there are any chunks left in the retransmit
648 * queue that could not fit in the PMTU sized packet, they need
649 * to be marked as ineligible for a subsequent fast retransmit.
651 if (rtx_timeout && !lchunk) {
652 list_for_each(lchunk1, lqueue) {
653 chunk1 = list_entry(lchunk1, struct sctp_chunk,
654 transmitted_list);
655 if (chunk1->fast_retransmit > 0)
656 chunk1->fast_retransmit = -1;
661 return error;
664 /* Cork the outqueue so queued chunks are really queued. */
665 int sctp_outq_uncork(struct sctp_outq *q)
667 int error = 0;
668 if (q->cork)
669 q->cork = 0;
670 error = sctp_outq_flush(q, 0);
671 return error;
675 * Try to flush an outqueue.
677 * Description: Send everything in q which we legally can, subject to
678 * congestion limitations.
679 * * Note: This function can be called from multiple contexts so appropriate
680 * locking concerns must be made. Today we use the sock lock to protect
681 * this function.
683 int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout)
685 struct sctp_packet *packet;
686 struct sctp_packet singleton;
687 struct sctp_association *asoc = q->asoc;
688 __u16 sport = asoc->base.bind_addr.port;
689 __u16 dport = asoc->peer.port;
690 __u32 vtag = asoc->peer.i.init_tag;
691 struct sctp_transport *transport = NULL;
692 struct sctp_transport *new_transport;
693 struct sctp_chunk *chunk, *tmp;
694 sctp_xmit_t status;
695 int error = 0;
696 int start_timer = 0;
698 /* These transports have chunks to send. */
699 struct list_head transport_list;
700 struct list_head *ltransport;
702 INIT_LIST_HEAD(&transport_list);
703 packet = NULL;
706 * 6.10 Bundling
707 * ...
708 * When bundling control chunks with DATA chunks, an
709 * endpoint MUST place control chunks first in the outbound
710 * SCTP packet. The transmitter MUST transmit DATA chunks
711 * within a SCTP packet in increasing order of TSN.
712 * ...
715 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) {
716 list_del_init(&chunk->list);
718 /* Pick the right transport to use. */
719 new_transport = chunk->transport;
721 if (!new_transport) {
723 * If we have a prior transport pointer, see if
724 * the destination address of the chunk
725 * matches the destination address of the
726 * current transport. If not a match, then
727 * try to look up the transport with a given
728 * destination address. We do this because
729 * after processing ASCONFs, we may have new
730 * transports created.
732 if (transport &&
733 sctp_cmp_addr_exact(&chunk->dest,
734 &transport->ipaddr))
735 new_transport = transport;
736 else
737 new_transport = sctp_assoc_lookup_paddr(asoc,
738 &chunk->dest);
740 /* if we still don't have a new transport, then
741 * use the current active path.
743 if (!new_transport)
744 new_transport = asoc->peer.active_path;
745 } else if ((new_transport->state == SCTP_INACTIVE) ||
746 (new_transport->state == SCTP_UNCONFIRMED)) {
747 /* If the chunk is Heartbeat or Heartbeat Ack,
748 * send it to chunk->transport, even if it's
749 * inactive.
751 * 3.3.6 Heartbeat Acknowledgement:
752 * ...
753 * A HEARTBEAT ACK is always sent to the source IP
754 * address of the IP datagram containing the
755 * HEARTBEAT chunk to which this ack is responding.
756 * ...
758 * ASCONF_ACKs also must be sent to the source.
760 if (chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT &&
761 chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT_ACK &&
762 chunk->chunk_hdr->type != SCTP_CID_ASCONF_ACK)
763 new_transport = asoc->peer.active_path;
766 /* Are we switching transports?
767 * Take care of transport locks.
769 if (new_transport != transport) {
770 transport = new_transport;
771 if (list_empty(&transport->send_ready)) {
772 list_add_tail(&transport->send_ready,
773 &transport_list);
775 packet = &transport->packet;
776 sctp_packet_config(packet, vtag,
777 asoc->peer.ecn_capable);
780 switch (chunk->chunk_hdr->type) {
782 * 6.10 Bundling
783 * ...
784 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN
785 * COMPLETE with any other chunks. [Send them immediately.]
787 case SCTP_CID_INIT:
788 case SCTP_CID_INIT_ACK:
789 case SCTP_CID_SHUTDOWN_COMPLETE:
790 sctp_packet_init(&singleton, transport, sport, dport);
791 sctp_packet_config(&singleton, vtag, 0);
792 sctp_packet_append_chunk(&singleton, chunk);
793 error = sctp_packet_transmit(&singleton);
794 if (error < 0)
795 return error;
796 break;
798 case SCTP_CID_ABORT:
799 case SCTP_CID_SACK:
800 case SCTP_CID_HEARTBEAT:
801 case SCTP_CID_HEARTBEAT_ACK:
802 case SCTP_CID_SHUTDOWN:
803 case SCTP_CID_SHUTDOWN_ACK:
804 case SCTP_CID_ERROR:
805 case SCTP_CID_COOKIE_ECHO:
806 case SCTP_CID_COOKIE_ACK:
807 case SCTP_CID_ECN_ECNE:
808 case SCTP_CID_ECN_CWR:
809 case SCTP_CID_ASCONF:
810 case SCTP_CID_ASCONF_ACK:
811 case SCTP_CID_FWD_TSN:
812 sctp_packet_transmit_chunk(packet, chunk);
813 break;
815 default:
816 /* We built a chunk with an illegal type! */
817 BUG();
821 /* Is it OK to send data chunks? */
822 switch (asoc->state) {
823 case SCTP_STATE_COOKIE_ECHOED:
824 /* Only allow bundling when this packet has a COOKIE-ECHO
825 * chunk.
827 if (!packet || !packet->has_cookie_echo)
828 break;
830 /* fallthru */
831 case SCTP_STATE_ESTABLISHED:
832 case SCTP_STATE_SHUTDOWN_PENDING:
833 case SCTP_STATE_SHUTDOWN_RECEIVED:
835 * RFC 2960 6.1 Transmission of DATA Chunks
837 * C) When the time comes for the sender to transmit,
838 * before sending new DATA chunks, the sender MUST
839 * first transmit any outstanding DATA chunks which
840 * are marked for retransmission (limited by the
841 * current cwnd).
843 if (!list_empty(&q->retransmit)) {
844 if (transport == asoc->peer.retran_path)
845 goto retran;
847 /* Switch transports & prepare the packet. */
849 transport = asoc->peer.retran_path;
851 if (list_empty(&transport->send_ready)) {
852 list_add_tail(&transport->send_ready,
853 &transport_list);
856 packet = &transport->packet;
857 sctp_packet_config(packet, vtag,
858 asoc->peer.ecn_capable);
859 retran:
860 error = sctp_outq_flush_rtx(q, packet,
861 rtx_timeout, &start_timer);
863 if (start_timer)
864 sctp_transport_reset_timers(transport);
866 /* This can happen on COOKIE-ECHO resend. Only
867 * one chunk can get bundled with a COOKIE-ECHO.
869 if (packet->has_cookie_echo)
870 goto sctp_flush_out;
872 /* Don't send new data if there is still data
873 * waiting to retransmit.
875 if (!list_empty(&q->retransmit))
876 goto sctp_flush_out;
879 /* Finally, transmit new packets. */
880 start_timer = 0;
881 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) {
882 /* RFC 2960 6.5 Every DATA chunk MUST carry a valid
883 * stream identifier.
885 if (chunk->sinfo.sinfo_stream >=
886 asoc->c.sinit_num_ostreams) {
888 /* Mark as failed send. */
889 sctp_chunk_fail(chunk, SCTP_ERROR_INV_STRM);
890 sctp_chunk_free(chunk);
891 continue;
894 /* Has this chunk expired? */
895 if (sctp_chunk_abandoned(chunk)) {
896 sctp_chunk_fail(chunk, 0);
897 sctp_chunk_free(chunk);
898 continue;
901 /* If there is a specified transport, use it.
902 * Otherwise, we want to use the active path.
904 new_transport = chunk->transport;
905 if (!new_transport ||
906 ((new_transport->state == SCTP_INACTIVE) ||
907 (new_transport->state == SCTP_UNCONFIRMED)))
908 new_transport = asoc->peer.active_path;
910 /* Change packets if necessary. */
911 if (new_transport != transport) {
912 transport = new_transport;
914 /* Schedule to have this transport's
915 * packet flushed.
917 if (list_empty(&transport->send_ready)) {
918 list_add_tail(&transport->send_ready,
919 &transport_list);
922 packet = &transport->packet;
923 sctp_packet_config(packet, vtag,
924 asoc->peer.ecn_capable);
927 SCTP_DEBUG_PRINTK("sctp_outq_flush(%p, %p[%s]), ",
928 q, chunk,
929 chunk && chunk->chunk_hdr ?
930 sctp_cname(SCTP_ST_CHUNK(
931 chunk->chunk_hdr->type))
932 : "Illegal Chunk");
934 SCTP_DEBUG_PRINTK("TX TSN 0x%x skb->head "
935 "%p skb->users %d.\n",
936 ntohl(chunk->subh.data_hdr->tsn),
937 chunk->skb ?chunk->skb->head : NULL,
938 chunk->skb ?
939 atomic_read(&chunk->skb->users) : -1);
941 /* Add the chunk to the packet. */
942 status = sctp_packet_transmit_chunk(packet, chunk);
944 switch (status) {
945 case SCTP_XMIT_PMTU_FULL:
946 case SCTP_XMIT_RWND_FULL:
947 case SCTP_XMIT_NAGLE_DELAY:
948 /* We could not append this chunk, so put
949 * the chunk back on the output queue.
951 SCTP_DEBUG_PRINTK("sctp_outq_flush: could "
952 "not transmit TSN: 0x%x, status: %d\n",
953 ntohl(chunk->subh.data_hdr->tsn),
954 status);
955 sctp_outq_head_data(q, chunk);
956 goto sctp_flush_out;
957 break;
959 case SCTP_XMIT_OK:
960 break;
962 default:
963 BUG();
966 /* BUG: We assume that the sctp_packet_transmit()
967 * call below will succeed all the time and add the
968 * chunk to the transmitted list and restart the
969 * timers.
970 * It is possible that the call can fail under OOM
971 * conditions.
973 * Is this really a problem? Won't this behave
974 * like a lost TSN?
976 list_add_tail(&chunk->transmitted_list,
977 &transport->transmitted);
979 sctp_transport_reset_timers(transport);
981 q->empty = 0;
983 /* Only let one DATA chunk get bundled with a
984 * COOKIE-ECHO chunk.
986 if (packet->has_cookie_echo)
987 goto sctp_flush_out;
989 break;
991 default:
992 /* Do nothing. */
993 break;
996 sctp_flush_out:
998 /* Before returning, examine all the transports touched in
999 * this call. Right now, we bluntly force clear all the
1000 * transports. Things might change after we implement Nagle.
1001 * But such an examination is still required.
1003 * --xguo
1005 while ((ltransport = sctp_list_dequeue(&transport_list)) != NULL ) {
1006 struct sctp_transport *t = list_entry(ltransport,
1007 struct sctp_transport,
1008 send_ready);
1009 packet = &t->packet;
1010 if (!sctp_packet_empty(packet))
1011 error = sctp_packet_transmit(packet);
1014 return error;
1017 /* Update unack_data based on the incoming SACK chunk */
1018 static void sctp_sack_update_unack_data(struct sctp_association *assoc,
1019 struct sctp_sackhdr *sack)
1021 sctp_sack_variable_t *frags;
1022 __u16 unack_data;
1023 int i;
1025 unack_data = assoc->next_tsn - assoc->ctsn_ack_point - 1;
1027 frags = sack->variable;
1028 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); i++) {
1029 unack_data -= ((ntohs(frags[i].gab.end) -
1030 ntohs(frags[i].gab.start) + 1));
1033 assoc->unack_data = unack_data;
1036 /* Return the highest new tsn that is acknowledged by the given SACK chunk. */
1037 static __u32 sctp_highest_new_tsn(struct sctp_sackhdr *sack,
1038 struct sctp_association *asoc)
1040 struct list_head *ltransport, *lchunk;
1041 struct sctp_transport *transport;
1042 struct sctp_chunk *chunk;
1043 __u32 highest_new_tsn, tsn;
1044 struct list_head *transport_list = &asoc->peer.transport_addr_list;
1046 highest_new_tsn = ntohl(sack->cum_tsn_ack);
1048 list_for_each(ltransport, transport_list) {
1049 transport = list_entry(ltransport, struct sctp_transport,
1050 transports);
1051 list_for_each(lchunk, &transport->transmitted) {
1052 chunk = list_entry(lchunk, struct sctp_chunk,
1053 transmitted_list);
1054 tsn = ntohl(chunk->subh.data_hdr->tsn);
1056 if (!chunk->tsn_gap_acked &&
1057 TSN_lt(highest_new_tsn, tsn) &&
1058 sctp_acked(sack, tsn))
1059 highest_new_tsn = tsn;
1063 return highest_new_tsn;
1066 /* This is where we REALLY process a SACK.
1068 * Process the SACK against the outqueue. Mostly, this just frees
1069 * things off the transmitted queue.
1071 int sctp_outq_sack(struct sctp_outq *q, struct sctp_sackhdr *sack)
1073 struct sctp_association *asoc = q->asoc;
1074 struct sctp_transport *transport;
1075 struct sctp_chunk *tchunk = NULL;
1076 struct list_head *lchunk, *transport_list, *pos, *temp;
1077 sctp_sack_variable_t *frags = sack->variable;
1078 __u32 sack_ctsn, ctsn, tsn;
1079 __u32 highest_tsn, highest_new_tsn;
1080 __u32 sack_a_rwnd;
1081 unsigned outstanding;
1082 struct sctp_transport *primary = asoc->peer.primary_path;
1083 int count_of_newacks = 0;
1085 /* Grab the association's destination address list. */
1086 transport_list = &asoc->peer.transport_addr_list;
1088 sack_ctsn = ntohl(sack->cum_tsn_ack);
1091 * SFR-CACC algorithm:
1092 * On receipt of a SACK the sender SHOULD execute the
1093 * following statements.
1095 * 1) If the cumulative ack in the SACK passes next tsn_at_change
1096 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be
1097 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for
1098 * all destinations.
1100 if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) {
1101 primary->cacc.changeover_active = 0;
1102 list_for_each(pos, transport_list) {
1103 transport = list_entry(pos, struct sctp_transport,
1104 transports);
1105 transport->cacc.cycling_changeover = 0;
1110 * SFR-CACC algorithm:
1111 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE
1112 * is set the receiver of the SACK MUST take the following actions:
1114 * A) Initialize the cacc_saw_newack to 0 for all destination
1115 * addresses.
1117 if (sack->num_gap_ack_blocks &&
1118 primary->cacc.changeover_active) {
1119 list_for_each(pos, transport_list) {
1120 transport = list_entry(pos, struct sctp_transport,
1121 transports);
1122 transport->cacc.cacc_saw_newack = 0;
1126 /* Get the highest TSN in the sack. */
1127 highest_tsn = sack_ctsn;
1128 if (sack->num_gap_ack_blocks)
1129 highest_tsn +=
1130 ntohs(frags[ntohs(sack->num_gap_ack_blocks) - 1].gab.end);
1132 if (TSN_lt(asoc->highest_sacked, highest_tsn)) {
1133 highest_new_tsn = highest_tsn;
1134 asoc->highest_sacked = highest_tsn;
1135 } else {
1136 highest_new_tsn = sctp_highest_new_tsn(sack, asoc);
1139 /* Run through the retransmit queue. Credit bytes received
1140 * and free those chunks that we can.
1142 sctp_check_transmitted(q, &q->retransmit, NULL, sack, highest_new_tsn);
1143 sctp_mark_missing(q, &q->retransmit, NULL, highest_new_tsn, 0);
1145 /* Run through the transmitted queue.
1146 * Credit bytes received and free those chunks which we can.
1148 * This is a MASSIVE candidate for optimization.
1150 list_for_each(pos, transport_list) {
1151 transport = list_entry(pos, struct sctp_transport,
1152 transports);
1153 sctp_check_transmitted(q, &transport->transmitted,
1154 transport, sack, highest_new_tsn);
1156 * SFR-CACC algorithm:
1157 * C) Let count_of_newacks be the number of
1158 * destinations for which cacc_saw_newack is set.
1160 if (transport->cacc.cacc_saw_newack)
1161 count_of_newacks ++;
1164 list_for_each(pos, transport_list) {
1165 transport = list_entry(pos, struct sctp_transport,
1166 transports);
1167 sctp_mark_missing(q, &transport->transmitted, transport,
1168 highest_new_tsn, count_of_newacks);
1171 /* Move the Cumulative TSN Ack Point if appropriate. */
1172 if (TSN_lt(asoc->ctsn_ack_point, sack_ctsn))
1173 asoc->ctsn_ack_point = sack_ctsn;
1175 /* Update unack_data field in the assoc. */
1176 sctp_sack_update_unack_data(asoc, sack);
1178 ctsn = asoc->ctsn_ack_point;
1180 /* Throw away stuff rotting on the sack queue. */
1181 list_for_each_safe(lchunk, temp, &q->sacked) {
1182 tchunk = list_entry(lchunk, struct sctp_chunk,
1183 transmitted_list);
1184 tsn = ntohl(tchunk->subh.data_hdr->tsn);
1185 if (TSN_lte(tsn, ctsn)) {
1186 list_del_init(&tchunk->transmitted_list);
1187 sctp_chunk_free(tchunk);
1191 /* ii) Set rwnd equal to the newly received a_rwnd minus the
1192 * number of bytes still outstanding after processing the
1193 * Cumulative TSN Ack and the Gap Ack Blocks.
1196 sack_a_rwnd = ntohl(sack->a_rwnd);
1197 outstanding = q->outstanding_bytes;
1199 if (outstanding < sack_a_rwnd)
1200 sack_a_rwnd -= outstanding;
1201 else
1202 sack_a_rwnd = 0;
1204 asoc->peer.rwnd = sack_a_rwnd;
1206 sctp_generate_fwdtsn(q, sack_ctsn);
1208 SCTP_DEBUG_PRINTK("%s: sack Cumulative TSN Ack is 0x%x.\n",
1209 __func__, sack_ctsn);
1210 SCTP_DEBUG_PRINTK("%s: Cumulative TSN Ack of association, "
1211 "%p is 0x%x. Adv peer ack point: 0x%x\n",
1212 __func__, asoc, ctsn, asoc->adv_peer_ack_point);
1214 /* See if all chunks are acked.
1215 * Make sure the empty queue handler will get run later.
1217 q->empty = (list_empty(&q->out_chunk_list) &&
1218 list_empty(&q->control_chunk_list) &&
1219 list_empty(&q->retransmit));
1220 if (!q->empty)
1221 goto finish;
1223 list_for_each(pos, transport_list) {
1224 transport = list_entry(pos, struct sctp_transport,
1225 transports);
1226 q->empty = q->empty && list_empty(&transport->transmitted);
1227 if (!q->empty)
1228 goto finish;
1231 SCTP_DEBUG_PRINTK("sack queue is empty.\n");
1232 finish:
1233 return q->empty;
1236 /* Is the outqueue empty? */
1237 int sctp_outq_is_empty(const struct sctp_outq *q)
1239 return q->empty;
1242 /********************************************************************
1243 * 2nd Level Abstractions
1244 ********************************************************************/
1246 /* Go through a transport's transmitted list or the association's retransmit
1247 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked.
1248 * The retransmit list will not have an associated transport.
1250 * I added coherent debug information output. --xguo
1252 * Instead of printing 'sacked' or 'kept' for each TSN on the
1253 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5.
1254 * KEPT TSN6-TSN7, etc.
1256 static void sctp_check_transmitted(struct sctp_outq *q,
1257 struct list_head *transmitted_queue,
1258 struct sctp_transport *transport,
1259 struct sctp_sackhdr *sack,
1260 __u32 highest_new_tsn_in_sack)
1262 struct list_head *lchunk;
1263 struct sctp_chunk *tchunk;
1264 struct list_head tlist;
1265 __u32 tsn;
1266 __u32 sack_ctsn;
1267 __u32 rtt;
1268 __u8 restart_timer = 0;
1269 int bytes_acked = 0;
1271 /* These state variables are for coherent debug output. --xguo */
1273 #if SCTP_DEBUG
1274 __u32 dbg_ack_tsn = 0; /* An ACKed TSN range starts here... */
1275 __u32 dbg_last_ack_tsn = 0; /* ...and finishes here. */
1276 __u32 dbg_kept_tsn = 0; /* An un-ACKed range starts here... */
1277 __u32 dbg_last_kept_tsn = 0; /* ...and finishes here. */
1279 /* 0 : The last TSN was ACKed.
1280 * 1 : The last TSN was NOT ACKed (i.e. KEPT).
1281 * -1: We need to initialize.
1283 int dbg_prt_state = -1;
1284 #endif /* SCTP_DEBUG */
1286 sack_ctsn = ntohl(sack->cum_tsn_ack);
1288 INIT_LIST_HEAD(&tlist);
1290 /* The while loop will skip empty transmitted queues. */
1291 while (NULL != (lchunk = sctp_list_dequeue(transmitted_queue))) {
1292 tchunk = list_entry(lchunk, struct sctp_chunk,
1293 transmitted_list);
1295 if (sctp_chunk_abandoned(tchunk)) {
1296 /* Move the chunk to abandoned list. */
1297 sctp_insert_list(&q->abandoned, lchunk);
1299 /* If this chunk has not been acked, stop
1300 * considering it as 'outstanding'.
1302 if (!tchunk->tsn_gap_acked) {
1303 tchunk->transport->flight_size -=
1304 sctp_data_size(tchunk);
1305 q->outstanding_bytes -= sctp_data_size(tchunk);
1307 continue;
1310 tsn = ntohl(tchunk->subh.data_hdr->tsn);
1311 if (sctp_acked(sack, tsn)) {
1312 /* If this queue is the retransmit queue, the
1313 * retransmit timer has already reclaimed
1314 * the outstanding bytes for this chunk, so only
1315 * count bytes associated with a transport.
1317 if (transport) {
1318 /* If this chunk is being used for RTT
1319 * measurement, calculate the RTT and update
1320 * the RTO using this value.
1322 * 6.3.1 C5) Karn's algorithm: RTT measurements
1323 * MUST NOT be made using packets that were
1324 * retransmitted (and thus for which it is
1325 * ambiguous whether the reply was for the
1326 * first instance of the packet or a later
1327 * instance).
1329 if (!tchunk->tsn_gap_acked &&
1330 !tchunk->resent &&
1331 tchunk->rtt_in_progress) {
1332 tchunk->rtt_in_progress = 0;
1333 rtt = jiffies - tchunk->sent_at;
1334 sctp_transport_update_rto(transport,
1335 rtt);
1338 if (TSN_lte(tsn, sack_ctsn)) {
1339 /* RFC 2960 6.3.2 Retransmission Timer Rules
1341 * R3) Whenever a SACK is received
1342 * that acknowledges the DATA chunk
1343 * with the earliest outstanding TSN
1344 * for that address, restart T3-rtx
1345 * timer for that address with its
1346 * current RTO.
1348 restart_timer = 1;
1350 if (!tchunk->tsn_gap_acked) {
1351 tchunk->tsn_gap_acked = 1;
1352 bytes_acked += sctp_data_size(tchunk);
1354 * SFR-CACC algorithm:
1355 * 2) If the SACK contains gap acks
1356 * and the flag CHANGEOVER_ACTIVE is
1357 * set the receiver of the SACK MUST
1358 * take the following action:
1360 * B) For each TSN t being acked that
1361 * has not been acked in any SACK so
1362 * far, set cacc_saw_newack to 1 for
1363 * the destination that the TSN was
1364 * sent to.
1366 if (transport &&
1367 sack->num_gap_ack_blocks &&
1368 q->asoc->peer.primary_path->cacc.
1369 changeover_active)
1370 transport->cacc.cacc_saw_newack
1371 = 1;
1374 list_add_tail(&tchunk->transmitted_list,
1375 &q->sacked);
1376 } else {
1377 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2
1378 * M2) Each time a SACK arrives reporting
1379 * 'Stray DATA chunk(s)' record the highest TSN
1380 * reported as newly acknowledged, call this
1381 * value 'HighestTSNinSack'. A newly
1382 * acknowledged DATA chunk is one not
1383 * previously acknowledged in a SACK.
1385 * When the SCTP sender of data receives a SACK
1386 * chunk that acknowledges, for the first time,
1387 * the receipt of a DATA chunk, all the still
1388 * unacknowledged DATA chunks whose TSN is
1389 * older than that newly acknowledged DATA
1390 * chunk, are qualified as 'Stray DATA chunks'.
1392 if (!tchunk->tsn_gap_acked) {
1393 tchunk->tsn_gap_acked = 1;
1394 bytes_acked += sctp_data_size(tchunk);
1396 list_add_tail(lchunk, &tlist);
1399 #if SCTP_DEBUG
1400 switch (dbg_prt_state) {
1401 case 0: /* last TSN was ACKed */
1402 if (dbg_last_ack_tsn + 1 == tsn) {
1403 /* This TSN belongs to the
1404 * current ACK range.
1406 break;
1409 if (dbg_last_ack_tsn != dbg_ack_tsn) {
1410 /* Display the end of the
1411 * current range.
1413 SCTP_DEBUG_PRINTK("-%08x",
1414 dbg_last_ack_tsn);
1417 /* Start a new range. */
1418 SCTP_DEBUG_PRINTK(",%08x", tsn);
1419 dbg_ack_tsn = tsn;
1420 break;
1422 case 1: /* The last TSN was NOT ACKed. */
1423 if (dbg_last_kept_tsn != dbg_kept_tsn) {
1424 /* Display the end of current range. */
1425 SCTP_DEBUG_PRINTK("-%08x",
1426 dbg_last_kept_tsn);
1429 SCTP_DEBUG_PRINTK("\n");
1431 /* FALL THROUGH... */
1432 default:
1433 /* This is the first-ever TSN we examined. */
1434 /* Start a new range of ACK-ed TSNs. */
1435 SCTP_DEBUG_PRINTK("ACKed: %08x", tsn);
1436 dbg_prt_state = 0;
1437 dbg_ack_tsn = tsn;
1440 dbg_last_ack_tsn = tsn;
1441 #endif /* SCTP_DEBUG */
1443 } else {
1444 if (tchunk->tsn_gap_acked) {
1445 SCTP_DEBUG_PRINTK("%s: Receiver reneged on "
1446 "data TSN: 0x%x\n",
1447 __func__,
1448 tsn);
1449 tchunk->tsn_gap_acked = 0;
1451 bytes_acked -= sctp_data_size(tchunk);
1453 /* RFC 2960 6.3.2 Retransmission Timer Rules
1455 * R4) Whenever a SACK is received missing a
1456 * TSN that was previously acknowledged via a
1457 * Gap Ack Block, start T3-rtx for the
1458 * destination address to which the DATA
1459 * chunk was originally
1460 * transmitted if it is not already running.
1462 restart_timer = 1;
1465 list_add_tail(lchunk, &tlist);
1467 #if SCTP_DEBUG
1468 /* See the above comments on ACK-ed TSNs. */
1469 switch (dbg_prt_state) {
1470 case 1:
1471 if (dbg_last_kept_tsn + 1 == tsn)
1472 break;
1474 if (dbg_last_kept_tsn != dbg_kept_tsn)
1475 SCTP_DEBUG_PRINTK("-%08x",
1476 dbg_last_kept_tsn);
1478 SCTP_DEBUG_PRINTK(",%08x", tsn);
1479 dbg_kept_tsn = tsn;
1480 break;
1482 case 0:
1483 if (dbg_last_ack_tsn != dbg_ack_tsn)
1484 SCTP_DEBUG_PRINTK("-%08x",
1485 dbg_last_ack_tsn);
1486 SCTP_DEBUG_PRINTK("\n");
1488 /* FALL THROUGH... */
1489 default:
1490 SCTP_DEBUG_PRINTK("KEPT: %08x",tsn);
1491 dbg_prt_state = 1;
1492 dbg_kept_tsn = tsn;
1495 dbg_last_kept_tsn = tsn;
1496 #endif /* SCTP_DEBUG */
1500 #if SCTP_DEBUG
1501 /* Finish off the last range, displaying its ending TSN. */
1502 switch (dbg_prt_state) {
1503 case 0:
1504 if (dbg_last_ack_tsn != dbg_ack_tsn) {
1505 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_ack_tsn);
1506 } else {
1507 SCTP_DEBUG_PRINTK("\n");
1509 break;
1511 case 1:
1512 if (dbg_last_kept_tsn != dbg_kept_tsn) {
1513 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_kept_tsn);
1514 } else {
1515 SCTP_DEBUG_PRINTK("\n");
1518 #endif /* SCTP_DEBUG */
1519 if (transport) {
1520 if (bytes_acked) {
1521 /* 8.2. When an outstanding TSN is acknowledged,
1522 * the endpoint shall clear the error counter of
1523 * the destination transport address to which the
1524 * DATA chunk was last sent.
1525 * The association's overall error counter is
1526 * also cleared.
1528 transport->error_count = 0;
1529 transport->asoc->overall_error_count = 0;
1531 /* Mark the destination transport address as
1532 * active if it is not so marked.
1534 if ((transport->state == SCTP_INACTIVE) ||
1535 (transport->state == SCTP_UNCONFIRMED)) {
1536 sctp_assoc_control_transport(
1537 transport->asoc,
1538 transport,
1539 SCTP_TRANSPORT_UP,
1540 SCTP_RECEIVED_SACK);
1543 sctp_transport_raise_cwnd(transport, sack_ctsn,
1544 bytes_acked);
1546 transport->flight_size -= bytes_acked;
1547 q->outstanding_bytes -= bytes_acked;
1548 } else {
1549 /* RFC 2960 6.1, sctpimpguide-06 2.15.2
1550 * When a sender is doing zero window probing, it
1551 * should not timeout the association if it continues
1552 * to receive new packets from the receiver. The
1553 * reason is that the receiver MAY keep its window
1554 * closed for an indefinite time.
1555 * A sender is doing zero window probing when the
1556 * receiver's advertised window is zero, and there is
1557 * only one data chunk in flight to the receiver.
1559 if (!q->asoc->peer.rwnd &&
1560 !list_empty(&tlist) &&
1561 (sack_ctsn+2 == q->asoc->next_tsn)) {
1562 SCTP_DEBUG_PRINTK("%s: SACK received for zero "
1563 "window probe: %u\n",
1564 __func__, sack_ctsn);
1565 q->asoc->overall_error_count = 0;
1566 transport->error_count = 0;
1570 /* RFC 2960 6.3.2 Retransmission Timer Rules
1572 * R2) Whenever all outstanding data sent to an address have
1573 * been acknowledged, turn off the T3-rtx timer of that
1574 * address.
1576 if (!transport->flight_size) {
1577 if (timer_pending(&transport->T3_rtx_timer) &&
1578 del_timer(&transport->T3_rtx_timer)) {
1579 sctp_transport_put(transport);
1581 } else if (restart_timer) {
1582 if (!mod_timer(&transport->T3_rtx_timer,
1583 jiffies + transport->rto))
1584 sctp_transport_hold(transport);
1588 list_splice(&tlist, transmitted_queue);
1591 /* Mark chunks as missing and consequently may get retransmitted. */
1592 static void sctp_mark_missing(struct sctp_outq *q,
1593 struct list_head *transmitted_queue,
1594 struct sctp_transport *transport,
1595 __u32 highest_new_tsn_in_sack,
1596 int count_of_newacks)
1598 struct sctp_chunk *chunk;
1599 struct list_head *pos;
1600 __u32 tsn;
1601 char do_fast_retransmit = 0;
1602 struct sctp_transport *primary = q->asoc->peer.primary_path;
1604 list_for_each(pos, transmitted_queue) {
1606 chunk = list_entry(pos, struct sctp_chunk, transmitted_list);
1607 tsn = ntohl(chunk->subh.data_hdr->tsn);
1609 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all
1610 * 'Unacknowledged TSN's', if the TSN number of an
1611 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack'
1612 * value, increment the 'TSN.Missing.Report' count on that
1613 * chunk if it has NOT been fast retransmitted or marked for
1614 * fast retransmit already.
1616 if (!chunk->fast_retransmit &&
1617 !chunk->tsn_gap_acked &&
1618 TSN_lt(tsn, highest_new_tsn_in_sack)) {
1620 /* SFR-CACC may require us to skip marking
1621 * this chunk as missing.
1623 if (!transport || !sctp_cacc_skip(primary, transport,
1624 count_of_newacks, tsn)) {
1625 chunk->tsn_missing_report++;
1627 SCTP_DEBUG_PRINTK(
1628 "%s: TSN 0x%x missing counter: %d\n",
1629 __func__, tsn,
1630 chunk->tsn_missing_report);
1634 * M4) If any DATA chunk is found to have a
1635 * 'TSN.Missing.Report'
1636 * value larger than or equal to 3, mark that chunk for
1637 * retransmission and start the fast retransmit procedure.
1640 if (chunk->tsn_missing_report >= 3) {
1641 chunk->fast_retransmit = 1;
1642 do_fast_retransmit = 1;
1646 if (transport) {
1647 if (do_fast_retransmit)
1648 sctp_retransmit(q, transport, SCTP_RTXR_FAST_RTX);
1650 SCTP_DEBUG_PRINTK("%s: transport: %p, cwnd: %d, "
1651 "ssthresh: %d, flight_size: %d, pba: %d\n",
1652 __func__, transport, transport->cwnd,
1653 transport->ssthresh, transport->flight_size,
1654 transport->partial_bytes_acked);
1658 /* Is the given TSN acked by this packet? */
1659 static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn)
1661 int i;
1662 sctp_sack_variable_t *frags;
1663 __u16 gap;
1664 __u32 ctsn = ntohl(sack->cum_tsn_ack);
1666 if (TSN_lte(tsn, ctsn))
1667 goto pass;
1669 /* 3.3.4 Selective Acknowledgement (SACK) (3):
1671 * Gap Ack Blocks:
1672 * These fields contain the Gap Ack Blocks. They are repeated
1673 * for each Gap Ack Block up to the number of Gap Ack Blocks
1674 * defined in the Number of Gap Ack Blocks field. All DATA
1675 * chunks with TSNs greater than or equal to (Cumulative TSN
1676 * Ack + Gap Ack Block Start) and less than or equal to
1677 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack
1678 * Block are assumed to have been received correctly.
1681 frags = sack->variable;
1682 gap = tsn - ctsn;
1683 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); ++i) {
1684 if (TSN_lte(ntohs(frags[i].gab.start), gap) &&
1685 TSN_lte(gap, ntohs(frags[i].gab.end)))
1686 goto pass;
1689 return 0;
1690 pass:
1691 return 1;
1694 static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip *skiplist,
1695 int nskips, __be16 stream)
1697 int i;
1699 for (i = 0; i < nskips; i++) {
1700 if (skiplist[i].stream == stream)
1701 return i;
1703 return i;
1706 /* Create and add a fwdtsn chunk to the outq's control queue if needed. */
1707 static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 ctsn)
1709 struct sctp_association *asoc = q->asoc;
1710 struct sctp_chunk *ftsn_chunk = NULL;
1711 struct sctp_fwdtsn_skip ftsn_skip_arr[10];
1712 int nskips = 0;
1713 int skip_pos = 0;
1714 __u32 tsn;
1715 struct sctp_chunk *chunk;
1716 struct list_head *lchunk, *temp;
1718 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the
1719 * received SACK.
1721 * If (Advanced.Peer.Ack.Point < SackCumAck), then update
1722 * Advanced.Peer.Ack.Point to be equal to SackCumAck.
1724 if (TSN_lt(asoc->adv_peer_ack_point, ctsn))
1725 asoc->adv_peer_ack_point = ctsn;
1727 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point"
1728 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as
1729 * the chunk next in the out-queue space is marked as "abandoned" as
1730 * shown in the following example:
1732 * Assuming that a SACK arrived with the Cumulative TSN ACK 102
1733 * and the Advanced.Peer.Ack.Point is updated to this value:
1735 * out-queue at the end of ==> out-queue after Adv.Ack.Point
1736 * normal SACK processing local advancement
1737 * ... ...
1738 * Adv.Ack.Pt-> 102 acked 102 acked
1739 * 103 abandoned 103 abandoned
1740 * 104 abandoned Adv.Ack.P-> 104 abandoned
1741 * 105 105
1742 * 106 acked 106 acked
1743 * ... ...
1745 * In this example, the data sender successfully advanced the
1746 * "Advanced.Peer.Ack.Point" from 102 to 104 locally.
1748 list_for_each_safe(lchunk, temp, &q->abandoned) {
1749 chunk = list_entry(lchunk, struct sctp_chunk,
1750 transmitted_list);
1751 tsn = ntohl(chunk->subh.data_hdr->tsn);
1753 /* Remove any chunks in the abandoned queue that are acked by
1754 * the ctsn.
1756 if (TSN_lte(tsn, ctsn)) {
1757 list_del_init(lchunk);
1758 sctp_chunk_free(chunk);
1759 } else {
1760 if (TSN_lte(tsn, asoc->adv_peer_ack_point+1)) {
1761 asoc->adv_peer_ack_point = tsn;
1762 if (chunk->chunk_hdr->flags &
1763 SCTP_DATA_UNORDERED)
1764 continue;
1765 skip_pos = sctp_get_skip_pos(&ftsn_skip_arr[0],
1766 nskips,
1767 chunk->subh.data_hdr->stream);
1768 ftsn_skip_arr[skip_pos].stream =
1769 chunk->subh.data_hdr->stream;
1770 ftsn_skip_arr[skip_pos].ssn =
1771 chunk->subh.data_hdr->ssn;
1772 if (skip_pos == nskips)
1773 nskips++;
1774 if (nskips == 10)
1775 break;
1776 } else
1777 break;
1781 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point"
1782 * is greater than the Cumulative TSN ACK carried in the received
1783 * SACK, the data sender MUST send the data receiver a FORWARD TSN
1784 * chunk containing the latest value of the
1785 * "Advanced.Peer.Ack.Point".
1787 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD
1788 * list each stream and sequence number in the forwarded TSN. This
1789 * information will enable the receiver to easily find any
1790 * stranded TSN's waiting on stream reorder queues. Each stream
1791 * SHOULD only be reported once; this means that if multiple
1792 * abandoned messages occur in the same stream then only the
1793 * highest abandoned stream sequence number is reported. If the
1794 * total size of the FORWARD TSN does NOT fit in a single MTU then
1795 * the sender of the FORWARD TSN SHOULD lower the
1796 * Advanced.Peer.Ack.Point to the last TSN that will fit in a
1797 * single MTU.
1799 if (asoc->adv_peer_ack_point > ctsn)
1800 ftsn_chunk = sctp_make_fwdtsn(asoc, asoc->adv_peer_ack_point,
1801 nskips, &ftsn_skip_arr[0]);
1803 if (ftsn_chunk) {
1804 list_add_tail(&ftsn_chunk->list, &q->control_chunk_list);
1805 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);