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[pv_ops_mirror.git] / net / sctp / outqueue.c
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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.
7 * This file is part of the SCTP kernel reference Implementation
9 * These functions implement the sctp_outq class. The outqueue handles
10 * bundling and queueing of outgoing SCTP chunks.
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.
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.
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 fast_retransmit)
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 fast retransmit,
416 * only the chunk's that are marked for fast retransmit
417 * should be added to the retransmit queue. If we are doing
418 * retransmission due to a timeout or pmtu discovery, only the
419 * chunks that are not yet acked should be added to the
420 * retransmit queue.
422 if ((fast_retransmit && (chunk->fast_retransmit > 0)) ||
423 (!fast_retransmit && !chunk->tsn_gap_acked)) {
424 /* RFC 2960 6.2.1 Processing a Received SACK
426 * C) Any time a DATA chunk is marked for
427 * retransmission (via either T3-rtx timer expiration
428 * (Section 6.3.3) or via fast retransmit
429 * (Section 7.2.4)), add the data size of those
430 * chunks to the rwnd.
432 q->asoc->peer.rwnd += (sctp_data_size(chunk) +
433 sizeof(struct sk_buff));
434 q->outstanding_bytes -= sctp_data_size(chunk);
435 transport->flight_size -= sctp_data_size(chunk);
437 /* sctpimpguide-05 Section 2.8.2
438 * M5) If a T3-rtx timer expires, the
439 * 'TSN.Missing.Report' of all affected TSNs is set
440 * to 0.
442 chunk->tsn_missing_report = 0;
444 /* If a chunk that is being used for RTT measurement
445 * has to be retransmitted, we cannot use this chunk
446 * anymore for RTT measurements. Reset rto_pending so
447 * that a new RTT measurement is started when a new
448 * data chunk is sent.
450 if (chunk->rtt_in_progress) {
451 chunk->rtt_in_progress = 0;
452 transport->rto_pending = 0;
455 /* Move the chunk to the retransmit queue. The chunks
456 * on the retransmit queue are always kept in order.
458 list_del_init(lchunk);
459 sctp_insert_list(&q->retransmit, lchunk);
463 SCTP_DEBUG_PRINTK("%s: transport: %p, fast_retransmit: %d, "
464 "cwnd: %d, ssthresh: %d, flight_size: %d, "
465 "pba: %d\n", __FUNCTION__,
466 transport, fast_retransmit,
467 transport->cwnd, transport->ssthresh,
468 transport->flight_size,
469 transport->partial_bytes_acked);
473 /* Mark all the eligible packets on a transport for retransmission and force
474 * one packet out.
476 void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
477 sctp_retransmit_reason_t reason)
479 int error = 0;
480 __u8 fast_retransmit = 0;
482 switch(reason) {
483 case SCTP_RTXR_T3_RTX:
484 SCTP_INC_STATS(SCTP_MIB_T3_RETRANSMITS);
485 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_T3_RTX);
486 /* Update the retran path if the T3-rtx timer has expired for
487 * the current retran path.
489 if (transport == transport->asoc->peer.retran_path)
490 sctp_assoc_update_retran_path(transport->asoc);
491 break;
492 case SCTP_RTXR_FAST_RTX:
493 SCTP_INC_STATS(SCTP_MIB_FAST_RETRANSMITS);
494 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_FAST_RTX);
495 fast_retransmit = 1;
496 break;
497 case SCTP_RTXR_PMTUD:
498 SCTP_INC_STATS(SCTP_MIB_PMTUD_RETRANSMITS);
499 break;
500 default:
501 BUG();
504 sctp_retransmit_mark(q, transport, fast_retransmit);
506 /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination,
507 * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by
508 * following the procedures outlined in C1 - C5.
510 sctp_generate_fwdtsn(q, q->asoc->ctsn_ack_point);
512 error = sctp_outq_flush(q, /* rtx_timeout */ 1);
514 if (error)
515 q->asoc->base.sk->sk_err = -error;
519 * Transmit DATA chunks on the retransmit queue. Upon return from
520 * sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which
521 * need to be transmitted by the caller.
522 * We assume that pkt->transport has already been set.
524 * The return value is a normal kernel error return value.
526 static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
527 int rtx_timeout, int *start_timer)
529 struct list_head *lqueue;
530 struct list_head *lchunk, *lchunk1;
531 struct sctp_transport *transport = pkt->transport;
532 sctp_xmit_t status;
533 struct sctp_chunk *chunk, *chunk1;
534 struct sctp_association *asoc;
535 int error = 0;
537 asoc = q->asoc;
538 lqueue = &q->retransmit;
540 /* RFC 2960 6.3.3 Handle T3-rtx Expiration
542 * E3) Determine how many of the earliest (i.e., lowest TSN)
543 * outstanding DATA chunks for the address for which the
544 * T3-rtx has expired will fit into a single packet, subject
545 * to the MTU constraint for the path corresponding to the
546 * destination transport address to which the retransmission
547 * is being sent (this may be different from the address for
548 * which the timer expires [see Section 6.4]). Call this value
549 * K. Bundle and retransmit those K DATA chunks in a single
550 * packet to the destination endpoint.
552 * [Just to be painfully clear, if we are retransmitting
553 * because a timeout just happened, we should send only ONE
554 * packet of retransmitted data.]
556 lchunk = sctp_list_dequeue(lqueue);
558 while (lchunk) {
559 chunk = list_entry(lchunk, struct sctp_chunk,
560 transmitted_list);
562 /* Make sure that Gap Acked TSNs are not retransmitted. A
563 * simple approach is just to move such TSNs out of the
564 * way and into a 'transmitted' queue and skip to the
565 * next chunk.
567 if (chunk->tsn_gap_acked) {
568 list_add_tail(lchunk, &transport->transmitted);
569 lchunk = sctp_list_dequeue(lqueue);
570 continue;
573 /* Attempt to append this chunk to the packet. */
574 status = sctp_packet_append_chunk(pkt, chunk);
576 switch (status) {
577 case SCTP_XMIT_PMTU_FULL:
578 /* Send this packet. */
579 if ((error = sctp_packet_transmit(pkt)) == 0)
580 *start_timer = 1;
582 /* If we are retransmitting, we should only
583 * send a single packet.
585 if (rtx_timeout) {
586 list_add(lchunk, lqueue);
587 lchunk = NULL;
590 /* Bundle lchunk in the next round. */
591 break;
593 case SCTP_XMIT_RWND_FULL:
594 /* Send this packet. */
595 if ((error = sctp_packet_transmit(pkt)) == 0)
596 *start_timer = 1;
598 /* Stop sending DATA as there is no more room
599 * at the receiver.
601 list_add(lchunk, lqueue);
602 lchunk = NULL;
603 break;
605 case SCTP_XMIT_NAGLE_DELAY:
606 /* Send this packet. */
607 if ((error = sctp_packet_transmit(pkt)) == 0)
608 *start_timer = 1;
610 /* Stop sending DATA because of nagle delay. */
611 list_add(lchunk, lqueue);
612 lchunk = NULL;
613 break;
615 default:
616 /* The append was successful, so add this chunk to
617 * the transmitted list.
619 list_add_tail(lchunk, &transport->transmitted);
621 /* Mark the chunk as ineligible for fast retransmit
622 * after it is retransmitted.
624 if (chunk->fast_retransmit > 0)
625 chunk->fast_retransmit = -1;
627 *start_timer = 1;
628 q->empty = 0;
630 /* Retrieve a new chunk to bundle. */
631 lchunk = sctp_list_dequeue(lqueue);
632 break;
635 /* If we are here due to a retransmit timeout or a fast
636 * retransmit and if there are any chunks left in the retransmit
637 * queue that could not fit in the PMTU sized packet, they need * to be marked as ineligible for a subsequent fast retransmit.
639 if (rtx_timeout && !lchunk) {
640 list_for_each(lchunk1, lqueue) {
641 chunk1 = list_entry(lchunk1, struct sctp_chunk,
642 transmitted_list);
643 if (chunk1->fast_retransmit > 0)
644 chunk1->fast_retransmit = -1;
649 return error;
652 /* Cork the outqueue so queued chunks are really queued. */
653 int sctp_outq_uncork(struct sctp_outq *q)
655 int error = 0;
656 if (q->cork) {
657 q->cork = 0;
658 error = sctp_outq_flush(q, 0);
660 return error;
664 * Try to flush an outqueue.
666 * Description: Send everything in q which we legally can, subject to
667 * congestion limitations.
668 * * Note: This function can be called from multiple contexts so appropriate
669 * locking concerns must be made. Today we use the sock lock to protect
670 * this function.
672 int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout)
674 struct sctp_packet *packet;
675 struct sctp_packet singleton;
676 struct sctp_association *asoc = q->asoc;
677 __u16 sport = asoc->base.bind_addr.port;
678 __u16 dport = asoc->peer.port;
679 __u32 vtag = asoc->peer.i.init_tag;
680 struct sctp_transport *transport = NULL;
681 struct sctp_transport *new_transport;
682 struct sctp_chunk *chunk, *tmp;
683 sctp_xmit_t status;
684 int error = 0;
685 int start_timer = 0;
687 /* These transports have chunks to send. */
688 struct list_head transport_list;
689 struct list_head *ltransport;
691 INIT_LIST_HEAD(&transport_list);
692 packet = NULL;
695 * 6.10 Bundling
696 * ...
697 * When bundling control chunks with DATA chunks, an
698 * endpoint MUST place control chunks first in the outbound
699 * SCTP packet. The transmitter MUST transmit DATA chunks
700 * within a SCTP packet in increasing order of TSN.
701 * ...
704 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) {
705 list_del_init(&chunk->list);
707 /* Pick the right transport to use. */
708 new_transport = chunk->transport;
710 if (!new_transport) {
711 new_transport = asoc->peer.active_path;
712 } else if ((new_transport->state == SCTP_INACTIVE) ||
713 (new_transport->state == SCTP_UNCONFIRMED)) {
714 /* If the chunk is Heartbeat or Heartbeat Ack,
715 * send it to chunk->transport, even if it's
716 * inactive.
718 * 3.3.6 Heartbeat Acknowledgement:
719 * ...
720 * A HEARTBEAT ACK is always sent to the source IP
721 * address of the IP datagram containing the
722 * HEARTBEAT chunk to which this ack is responding.
723 * ...
725 if (chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT &&
726 chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT_ACK)
727 new_transport = asoc->peer.active_path;
730 /* Are we switching transports?
731 * Take care of transport locks.
733 if (new_transport != transport) {
734 transport = new_transport;
735 if (list_empty(&transport->send_ready)) {
736 list_add_tail(&transport->send_ready,
737 &transport_list);
739 packet = &transport->packet;
740 sctp_packet_config(packet, vtag,
741 asoc->peer.ecn_capable);
744 switch (chunk->chunk_hdr->type) {
746 * 6.10 Bundling
747 * ...
748 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN
749 * COMPLETE with any other chunks. [Send them immediately.]
751 case SCTP_CID_INIT:
752 case SCTP_CID_INIT_ACK:
753 case SCTP_CID_SHUTDOWN_COMPLETE:
754 sctp_packet_init(&singleton, transport, sport, dport);
755 sctp_packet_config(&singleton, vtag, 0);
756 sctp_packet_append_chunk(&singleton, chunk);
757 error = sctp_packet_transmit(&singleton);
758 if (error < 0)
759 return error;
760 break;
762 case SCTP_CID_ABORT:
763 case SCTP_CID_SACK:
764 case SCTP_CID_HEARTBEAT:
765 case SCTP_CID_HEARTBEAT_ACK:
766 case SCTP_CID_SHUTDOWN:
767 case SCTP_CID_SHUTDOWN_ACK:
768 case SCTP_CID_ERROR:
769 case SCTP_CID_COOKIE_ECHO:
770 case SCTP_CID_COOKIE_ACK:
771 case SCTP_CID_ECN_ECNE:
772 case SCTP_CID_ECN_CWR:
773 case SCTP_CID_ASCONF:
774 case SCTP_CID_ASCONF_ACK:
775 case SCTP_CID_FWD_TSN:
776 sctp_packet_transmit_chunk(packet, chunk);
777 break;
779 default:
780 /* We built a chunk with an illegal type! */
781 BUG();
785 /* Is it OK to send data chunks? */
786 switch (asoc->state) {
787 case SCTP_STATE_COOKIE_ECHOED:
788 /* Only allow bundling when this packet has a COOKIE-ECHO
789 * chunk.
791 if (!packet || !packet->has_cookie_echo)
792 break;
794 /* fallthru */
795 case SCTP_STATE_ESTABLISHED:
796 case SCTP_STATE_SHUTDOWN_PENDING:
797 case SCTP_STATE_SHUTDOWN_RECEIVED:
799 * RFC 2960 6.1 Transmission of DATA Chunks
801 * C) When the time comes for the sender to transmit,
802 * before sending new DATA chunks, the sender MUST
803 * first transmit any outstanding DATA chunks which
804 * are marked for retransmission (limited by the
805 * current cwnd).
807 if (!list_empty(&q->retransmit)) {
808 if (transport == asoc->peer.retran_path)
809 goto retran;
811 /* Switch transports & prepare the packet. */
813 transport = asoc->peer.retran_path;
815 if (list_empty(&transport->send_ready)) {
816 list_add_tail(&transport->send_ready,
817 &transport_list);
820 packet = &transport->packet;
821 sctp_packet_config(packet, vtag,
822 asoc->peer.ecn_capable);
823 retran:
824 error = sctp_outq_flush_rtx(q, packet,
825 rtx_timeout, &start_timer);
827 if (start_timer)
828 sctp_transport_reset_timers(transport);
830 /* This can happen on COOKIE-ECHO resend. Only
831 * one chunk can get bundled with a COOKIE-ECHO.
833 if (packet->has_cookie_echo)
834 goto sctp_flush_out;
836 /* Don't send new data if there is still data
837 * waiting to retransmit.
839 if (!list_empty(&q->retransmit))
840 goto sctp_flush_out;
843 /* Finally, transmit new packets. */
844 start_timer = 0;
845 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) {
846 /* RFC 2960 6.5 Every DATA chunk MUST carry a valid
847 * stream identifier.
849 if (chunk->sinfo.sinfo_stream >=
850 asoc->c.sinit_num_ostreams) {
852 /* Mark as failed send. */
853 sctp_chunk_fail(chunk, SCTP_ERROR_INV_STRM);
854 sctp_chunk_free(chunk);
855 continue;
858 /* Has this chunk expired? */
859 if (sctp_chunk_abandoned(chunk)) {
860 sctp_chunk_fail(chunk, 0);
861 sctp_chunk_free(chunk);
862 continue;
865 /* If there is a specified transport, use it.
866 * Otherwise, we want to use the active path.
868 new_transport = chunk->transport;
869 if (!new_transport ||
870 ((new_transport->state == SCTP_INACTIVE) ||
871 (new_transport->state == SCTP_UNCONFIRMED)))
872 new_transport = asoc->peer.active_path;
874 /* Change packets if necessary. */
875 if (new_transport != transport) {
876 transport = new_transport;
878 /* Schedule to have this transport's
879 * packet flushed.
881 if (list_empty(&transport->send_ready)) {
882 list_add_tail(&transport->send_ready,
883 &transport_list);
886 packet = &transport->packet;
887 sctp_packet_config(packet, vtag,
888 asoc->peer.ecn_capable);
891 SCTP_DEBUG_PRINTK("sctp_outq_flush(%p, %p[%s]), ",
892 q, chunk,
893 chunk && chunk->chunk_hdr ?
894 sctp_cname(SCTP_ST_CHUNK(
895 chunk->chunk_hdr->type))
896 : "Illegal Chunk");
898 SCTP_DEBUG_PRINTK("TX TSN 0x%x skb->head "
899 "%p skb->users %d.\n",
900 ntohl(chunk->subh.data_hdr->tsn),
901 chunk->skb ?chunk->skb->head : NULL,
902 chunk->skb ?
903 atomic_read(&chunk->skb->users) : -1);
905 /* Add the chunk to the packet. */
906 status = sctp_packet_transmit_chunk(packet, chunk);
908 switch (status) {
909 case SCTP_XMIT_PMTU_FULL:
910 case SCTP_XMIT_RWND_FULL:
911 case SCTP_XMIT_NAGLE_DELAY:
912 /* We could not append this chunk, so put
913 * the chunk back on the output queue.
915 SCTP_DEBUG_PRINTK("sctp_outq_flush: could "
916 "not transmit TSN: 0x%x, status: %d\n",
917 ntohl(chunk->subh.data_hdr->tsn),
918 status);
919 sctp_outq_head_data(q, chunk);
920 goto sctp_flush_out;
921 break;
923 case SCTP_XMIT_OK:
924 break;
926 default:
927 BUG();
930 /* BUG: We assume that the sctp_packet_transmit()
931 * call below will succeed all the time and add the
932 * chunk to the transmitted list and restart the
933 * timers.
934 * It is possible that the call can fail under OOM
935 * conditions.
937 * Is this really a problem? Won't this behave
938 * like a lost TSN?
940 list_add_tail(&chunk->transmitted_list,
941 &transport->transmitted);
943 sctp_transport_reset_timers(transport);
945 q->empty = 0;
947 /* Only let one DATA chunk get bundled with a
948 * COOKIE-ECHO chunk.
950 if (packet->has_cookie_echo)
951 goto sctp_flush_out;
953 break;
955 default:
956 /* Do nothing. */
957 break;
960 sctp_flush_out:
962 /* Before returning, examine all the transports touched in
963 * this call. Right now, we bluntly force clear all the
964 * transports. Things might change after we implement Nagle.
965 * But such an examination is still required.
967 * --xguo
969 while ((ltransport = sctp_list_dequeue(&transport_list)) != NULL ) {
970 struct sctp_transport *t = list_entry(ltransport,
971 struct sctp_transport,
972 send_ready);
973 packet = &t->packet;
974 if (!sctp_packet_empty(packet))
975 error = sctp_packet_transmit(packet);
978 return error;
981 /* Update unack_data based on the incoming SACK chunk */
982 static void sctp_sack_update_unack_data(struct sctp_association *assoc,
983 struct sctp_sackhdr *sack)
985 sctp_sack_variable_t *frags;
986 __u16 unack_data;
987 int i;
989 unack_data = assoc->next_tsn - assoc->ctsn_ack_point - 1;
991 frags = sack->variable;
992 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); i++) {
993 unack_data -= ((ntohs(frags[i].gab.end) -
994 ntohs(frags[i].gab.start) + 1));
997 assoc->unack_data = unack_data;
1000 /* Return the highest new tsn that is acknowledged by the given SACK chunk. */
1001 static __u32 sctp_highest_new_tsn(struct sctp_sackhdr *sack,
1002 struct sctp_association *asoc)
1004 struct list_head *ltransport, *lchunk;
1005 struct sctp_transport *transport;
1006 struct sctp_chunk *chunk;
1007 __u32 highest_new_tsn, tsn;
1008 struct list_head *transport_list = &asoc->peer.transport_addr_list;
1010 highest_new_tsn = ntohl(sack->cum_tsn_ack);
1012 list_for_each(ltransport, transport_list) {
1013 transport = list_entry(ltransport, struct sctp_transport,
1014 transports);
1015 list_for_each(lchunk, &transport->transmitted) {
1016 chunk = list_entry(lchunk, struct sctp_chunk,
1017 transmitted_list);
1018 tsn = ntohl(chunk->subh.data_hdr->tsn);
1020 if (!chunk->tsn_gap_acked &&
1021 TSN_lt(highest_new_tsn, tsn) &&
1022 sctp_acked(sack, tsn))
1023 highest_new_tsn = tsn;
1027 return highest_new_tsn;
1030 /* This is where we REALLY process a SACK.
1032 * Process the SACK against the outqueue. Mostly, this just frees
1033 * things off the transmitted queue.
1035 int sctp_outq_sack(struct sctp_outq *q, struct sctp_sackhdr *sack)
1037 struct sctp_association *asoc = q->asoc;
1038 struct sctp_transport *transport;
1039 struct sctp_chunk *tchunk = NULL;
1040 struct list_head *lchunk, *transport_list, *pos, *temp;
1041 sctp_sack_variable_t *frags = sack->variable;
1042 __u32 sack_ctsn, ctsn, tsn;
1043 __u32 highest_tsn, highest_new_tsn;
1044 __u32 sack_a_rwnd;
1045 unsigned outstanding;
1046 struct sctp_transport *primary = asoc->peer.primary_path;
1047 int count_of_newacks = 0;
1049 /* Grab the association's destination address list. */
1050 transport_list = &asoc->peer.transport_addr_list;
1052 sack_ctsn = ntohl(sack->cum_tsn_ack);
1055 * SFR-CACC algorithm:
1056 * On receipt of a SACK the sender SHOULD execute the
1057 * following statements.
1059 * 1) If the cumulative ack in the SACK passes next tsn_at_change
1060 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be
1061 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for
1062 * all destinations.
1064 if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) {
1065 primary->cacc.changeover_active = 0;
1066 list_for_each(pos, transport_list) {
1067 transport = list_entry(pos, struct sctp_transport,
1068 transports);
1069 transport->cacc.cycling_changeover = 0;
1074 * SFR-CACC algorithm:
1075 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE
1076 * is set the receiver of the SACK MUST take the following actions:
1078 * A) Initialize the cacc_saw_newack to 0 for all destination
1079 * addresses.
1081 if (sack->num_gap_ack_blocks &&
1082 primary->cacc.changeover_active) {
1083 list_for_each(pos, transport_list) {
1084 transport = list_entry(pos, struct sctp_transport,
1085 transports);
1086 transport->cacc.cacc_saw_newack = 0;
1090 /* Get the highest TSN in the sack. */
1091 highest_tsn = sack_ctsn;
1092 if (sack->num_gap_ack_blocks)
1093 highest_tsn +=
1094 ntohs(frags[ntohs(sack->num_gap_ack_blocks) - 1].gab.end);
1096 if (TSN_lt(asoc->highest_sacked, highest_tsn)) {
1097 highest_new_tsn = highest_tsn;
1098 asoc->highest_sacked = highest_tsn;
1099 } else {
1100 highest_new_tsn = sctp_highest_new_tsn(sack, asoc);
1103 /* Run through the retransmit queue. Credit bytes received
1104 * and free those chunks that we can.
1106 sctp_check_transmitted(q, &q->retransmit, NULL, sack, highest_new_tsn);
1107 sctp_mark_missing(q, &q->retransmit, NULL, highest_new_tsn, 0);
1109 /* Run through the transmitted queue.
1110 * Credit bytes received and free those chunks which we can.
1112 * This is a MASSIVE candidate for optimization.
1114 list_for_each(pos, transport_list) {
1115 transport = list_entry(pos, struct sctp_transport,
1116 transports);
1117 sctp_check_transmitted(q, &transport->transmitted,
1118 transport, sack, highest_new_tsn);
1120 * SFR-CACC algorithm:
1121 * C) Let count_of_newacks be the number of
1122 * destinations for which cacc_saw_newack is set.
1124 if (transport->cacc.cacc_saw_newack)
1125 count_of_newacks ++;
1128 list_for_each(pos, transport_list) {
1129 transport = list_entry(pos, struct sctp_transport,
1130 transports);
1131 sctp_mark_missing(q, &transport->transmitted, transport,
1132 highest_new_tsn, count_of_newacks);
1135 /* Move the Cumulative TSN Ack Point if appropriate. */
1136 if (TSN_lt(asoc->ctsn_ack_point, sack_ctsn))
1137 asoc->ctsn_ack_point = sack_ctsn;
1139 /* Update unack_data field in the assoc. */
1140 sctp_sack_update_unack_data(asoc, sack);
1142 ctsn = asoc->ctsn_ack_point;
1144 /* Throw away stuff rotting on the sack queue. */
1145 list_for_each_safe(lchunk, temp, &q->sacked) {
1146 tchunk = list_entry(lchunk, struct sctp_chunk,
1147 transmitted_list);
1148 tsn = ntohl(tchunk->subh.data_hdr->tsn);
1149 if (TSN_lte(tsn, ctsn))
1150 sctp_chunk_free(tchunk);
1153 /* ii) Set rwnd equal to the newly received a_rwnd minus the
1154 * number of bytes still outstanding after processing the
1155 * Cumulative TSN Ack and the Gap Ack Blocks.
1158 sack_a_rwnd = ntohl(sack->a_rwnd);
1159 outstanding = q->outstanding_bytes;
1161 if (outstanding < sack_a_rwnd)
1162 sack_a_rwnd -= outstanding;
1163 else
1164 sack_a_rwnd = 0;
1166 asoc->peer.rwnd = sack_a_rwnd;
1168 sctp_generate_fwdtsn(q, sack_ctsn);
1170 SCTP_DEBUG_PRINTK("%s: sack Cumulative TSN Ack is 0x%x.\n",
1171 __FUNCTION__, sack_ctsn);
1172 SCTP_DEBUG_PRINTK("%s: Cumulative TSN Ack of association, "
1173 "%p is 0x%x. Adv peer ack point: 0x%x\n",
1174 __FUNCTION__, asoc, ctsn, asoc->adv_peer_ack_point);
1176 /* See if all chunks are acked.
1177 * Make sure the empty queue handler will get run later.
1179 q->empty = (list_empty(&q->out_chunk_list) &&
1180 list_empty(&q->control_chunk_list) &&
1181 list_empty(&q->retransmit));
1182 if (!q->empty)
1183 goto finish;
1185 list_for_each(pos, transport_list) {
1186 transport = list_entry(pos, struct sctp_transport,
1187 transports);
1188 q->empty = q->empty && list_empty(&transport->transmitted);
1189 if (!q->empty)
1190 goto finish;
1193 SCTP_DEBUG_PRINTK("sack queue is empty.\n");
1194 finish:
1195 return q->empty;
1198 /* Is the outqueue empty? */
1199 int sctp_outq_is_empty(const struct sctp_outq *q)
1201 return q->empty;
1204 /********************************************************************
1205 * 2nd Level Abstractions
1206 ********************************************************************/
1208 /* Go through a transport's transmitted list or the association's retransmit
1209 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked.
1210 * The retransmit list will not have an associated transport.
1212 * I added coherent debug information output. --xguo
1214 * Instead of printing 'sacked' or 'kept' for each TSN on the
1215 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5.
1216 * KEPT TSN6-TSN7, etc.
1218 static void sctp_check_transmitted(struct sctp_outq *q,
1219 struct list_head *transmitted_queue,
1220 struct sctp_transport *transport,
1221 struct sctp_sackhdr *sack,
1222 __u32 highest_new_tsn_in_sack)
1224 struct list_head *lchunk;
1225 struct sctp_chunk *tchunk;
1226 struct list_head tlist;
1227 __u32 tsn;
1228 __u32 sack_ctsn;
1229 __u32 rtt;
1230 __u8 restart_timer = 0;
1231 int bytes_acked = 0;
1233 /* These state variables are for coherent debug output. --xguo */
1235 #if SCTP_DEBUG
1236 __u32 dbg_ack_tsn = 0; /* An ACKed TSN range starts here... */
1237 __u32 dbg_last_ack_tsn = 0; /* ...and finishes here. */
1238 __u32 dbg_kept_tsn = 0; /* An un-ACKed range starts here... */
1239 __u32 dbg_last_kept_tsn = 0; /* ...and finishes here. */
1241 /* 0 : The last TSN was ACKed.
1242 * 1 : The last TSN was NOT ACKed (i.e. KEPT).
1243 * -1: We need to initialize.
1245 int dbg_prt_state = -1;
1246 #endif /* SCTP_DEBUG */
1248 sack_ctsn = ntohl(sack->cum_tsn_ack);
1250 INIT_LIST_HEAD(&tlist);
1252 /* The while loop will skip empty transmitted queues. */
1253 while (NULL != (lchunk = sctp_list_dequeue(transmitted_queue))) {
1254 tchunk = list_entry(lchunk, struct sctp_chunk,
1255 transmitted_list);
1257 if (sctp_chunk_abandoned(tchunk)) {
1258 /* Move the chunk to abandoned list. */
1259 sctp_insert_list(&q->abandoned, lchunk);
1261 /* If this chunk has not been acked, stop
1262 * considering it as 'outstanding'.
1264 if (!tchunk->tsn_gap_acked) {
1265 tchunk->transport->flight_size -=
1266 sctp_data_size(tchunk);
1267 q->outstanding_bytes -= sctp_data_size(tchunk);
1269 continue;
1272 tsn = ntohl(tchunk->subh.data_hdr->tsn);
1273 if (sctp_acked(sack, tsn)) {
1274 /* If this queue is the retransmit queue, the
1275 * retransmit timer has already reclaimed
1276 * the outstanding bytes for this chunk, so only
1277 * count bytes associated with a transport.
1279 if (transport) {
1280 /* If this chunk is being used for RTT
1281 * measurement, calculate the RTT and update
1282 * the RTO using this value.
1284 * 6.3.1 C5) Karn's algorithm: RTT measurements
1285 * MUST NOT be made using packets that were
1286 * retransmitted (and thus for which it is
1287 * ambiguous whether the reply was for the
1288 * first instance of the packet or a later
1289 * instance).
1291 if (!tchunk->tsn_gap_acked &&
1292 !tchunk->resent &&
1293 tchunk->rtt_in_progress) {
1294 tchunk->rtt_in_progress = 0;
1295 rtt = jiffies - tchunk->sent_at;
1296 sctp_transport_update_rto(transport,
1297 rtt);
1300 if (TSN_lte(tsn, sack_ctsn)) {
1301 /* RFC 2960 6.3.2 Retransmission Timer Rules
1303 * R3) Whenever a SACK is received
1304 * that acknowledges the DATA chunk
1305 * with the earliest outstanding TSN
1306 * for that address, restart T3-rtx
1307 * timer for that address with its
1308 * current RTO.
1310 restart_timer = 1;
1312 if (!tchunk->tsn_gap_acked) {
1313 tchunk->tsn_gap_acked = 1;
1314 bytes_acked += sctp_data_size(tchunk);
1316 * SFR-CACC algorithm:
1317 * 2) If the SACK contains gap acks
1318 * and the flag CHANGEOVER_ACTIVE is
1319 * set the receiver of the SACK MUST
1320 * take the following action:
1322 * B) For each TSN t being acked that
1323 * has not been acked in any SACK so
1324 * far, set cacc_saw_newack to 1 for
1325 * the destination that the TSN was
1326 * sent to.
1328 if (transport &&
1329 sack->num_gap_ack_blocks &&
1330 q->asoc->peer.primary_path->cacc.
1331 changeover_active)
1332 transport->cacc.cacc_saw_newack
1333 = 1;
1336 list_add_tail(&tchunk->transmitted_list,
1337 &q->sacked);
1338 } else {
1339 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2
1340 * M2) Each time a SACK arrives reporting
1341 * 'Stray DATA chunk(s)' record the highest TSN
1342 * reported as newly acknowledged, call this
1343 * value 'HighestTSNinSack'. A newly
1344 * acknowledged DATA chunk is one not
1345 * previously acknowledged in a SACK.
1347 * When the SCTP sender of data receives a SACK
1348 * chunk that acknowledges, for the first time,
1349 * the receipt of a DATA chunk, all the still
1350 * unacknowledged DATA chunks whose TSN is
1351 * older than that newly acknowledged DATA
1352 * chunk, are qualified as 'Stray DATA chunks'.
1354 if (!tchunk->tsn_gap_acked) {
1355 tchunk->tsn_gap_acked = 1;
1356 bytes_acked += sctp_data_size(tchunk);
1358 list_add_tail(lchunk, &tlist);
1361 #if SCTP_DEBUG
1362 switch (dbg_prt_state) {
1363 case 0: /* last TSN was ACKed */
1364 if (dbg_last_ack_tsn + 1 == tsn) {
1365 /* This TSN belongs to the
1366 * current ACK range.
1368 break;
1371 if (dbg_last_ack_tsn != dbg_ack_tsn) {
1372 /* Display the end of the
1373 * current range.
1375 SCTP_DEBUG_PRINTK("-%08x",
1376 dbg_last_ack_tsn);
1379 /* Start a new range. */
1380 SCTP_DEBUG_PRINTK(",%08x", tsn);
1381 dbg_ack_tsn = tsn;
1382 break;
1384 case 1: /* The last TSN was NOT ACKed. */
1385 if (dbg_last_kept_tsn != dbg_kept_tsn) {
1386 /* Display the end of current range. */
1387 SCTP_DEBUG_PRINTK("-%08x",
1388 dbg_last_kept_tsn);
1391 SCTP_DEBUG_PRINTK("\n");
1393 /* FALL THROUGH... */
1394 default:
1395 /* This is the first-ever TSN we examined. */
1396 /* Start a new range of ACK-ed TSNs. */
1397 SCTP_DEBUG_PRINTK("ACKed: %08x", tsn);
1398 dbg_prt_state = 0;
1399 dbg_ack_tsn = tsn;
1402 dbg_last_ack_tsn = tsn;
1403 #endif /* SCTP_DEBUG */
1405 } else {
1406 if (tchunk->tsn_gap_acked) {
1407 SCTP_DEBUG_PRINTK("%s: Receiver reneged on "
1408 "data TSN: 0x%x\n",
1409 __FUNCTION__,
1410 tsn);
1411 tchunk->tsn_gap_acked = 0;
1413 bytes_acked -= sctp_data_size(tchunk);
1415 /* RFC 2960 6.3.2 Retransmission Timer Rules
1417 * R4) Whenever a SACK is received missing a
1418 * TSN that was previously acknowledged via a
1419 * Gap Ack Block, start T3-rtx for the
1420 * destination address to which the DATA
1421 * chunk was originally
1422 * transmitted if it is not already running.
1424 restart_timer = 1;
1427 list_add_tail(lchunk, &tlist);
1429 #if SCTP_DEBUG
1430 /* See the above comments on ACK-ed TSNs. */
1431 switch (dbg_prt_state) {
1432 case 1:
1433 if (dbg_last_kept_tsn + 1 == tsn)
1434 break;
1436 if (dbg_last_kept_tsn != dbg_kept_tsn)
1437 SCTP_DEBUG_PRINTK("-%08x",
1438 dbg_last_kept_tsn);
1440 SCTP_DEBUG_PRINTK(",%08x", tsn);
1441 dbg_kept_tsn = tsn;
1442 break;
1444 case 0:
1445 if (dbg_last_ack_tsn != dbg_ack_tsn)
1446 SCTP_DEBUG_PRINTK("-%08x",
1447 dbg_last_ack_tsn);
1448 SCTP_DEBUG_PRINTK("\n");
1450 /* FALL THROUGH... */
1451 default:
1452 SCTP_DEBUG_PRINTK("KEPT: %08x",tsn);
1453 dbg_prt_state = 1;
1454 dbg_kept_tsn = tsn;
1457 dbg_last_kept_tsn = tsn;
1458 #endif /* SCTP_DEBUG */
1462 #if SCTP_DEBUG
1463 /* Finish off the last range, displaying its ending TSN. */
1464 switch (dbg_prt_state) {
1465 case 0:
1466 if (dbg_last_ack_tsn != dbg_ack_tsn) {
1467 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_ack_tsn);
1468 } else {
1469 SCTP_DEBUG_PRINTK("\n");
1471 break;
1473 case 1:
1474 if (dbg_last_kept_tsn != dbg_kept_tsn) {
1475 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_kept_tsn);
1476 } else {
1477 SCTP_DEBUG_PRINTK("\n");
1480 #endif /* SCTP_DEBUG */
1481 if (transport) {
1482 if (bytes_acked) {
1483 /* 8.2. When an outstanding TSN is acknowledged,
1484 * the endpoint shall clear the error counter of
1485 * the destination transport address to which the
1486 * DATA chunk was last sent.
1487 * The association's overall error counter is
1488 * also cleared.
1490 transport->error_count = 0;
1491 transport->asoc->overall_error_count = 0;
1493 /* Mark the destination transport address as
1494 * active if it is not so marked.
1496 if ((transport->state == SCTP_INACTIVE) ||
1497 (transport->state == SCTP_UNCONFIRMED)) {
1498 sctp_assoc_control_transport(
1499 transport->asoc,
1500 transport,
1501 SCTP_TRANSPORT_UP,
1502 SCTP_RECEIVED_SACK);
1505 sctp_transport_raise_cwnd(transport, sack_ctsn,
1506 bytes_acked);
1508 transport->flight_size -= bytes_acked;
1509 q->outstanding_bytes -= bytes_acked;
1510 } else {
1511 /* RFC 2960 6.1, sctpimpguide-06 2.15.2
1512 * When a sender is doing zero window probing, it
1513 * should not timeout the association if it continues
1514 * to receive new packets from the receiver. The
1515 * reason is that the receiver MAY keep its window
1516 * closed for an indefinite time.
1517 * A sender is doing zero window probing when the
1518 * receiver's advertised window is zero, and there is
1519 * only one data chunk in flight to the receiver.
1521 if (!q->asoc->peer.rwnd &&
1522 !list_empty(&tlist) &&
1523 (sack_ctsn+2 == q->asoc->next_tsn)) {
1524 SCTP_DEBUG_PRINTK("%s: SACK received for zero "
1525 "window probe: %u\n",
1526 __FUNCTION__, sack_ctsn);
1527 q->asoc->overall_error_count = 0;
1528 transport->error_count = 0;
1532 /* RFC 2960 6.3.2 Retransmission Timer Rules
1534 * R2) Whenever all outstanding data sent to an address have
1535 * been acknowledged, turn off the T3-rtx timer of that
1536 * address.
1538 if (!transport->flight_size) {
1539 if (timer_pending(&transport->T3_rtx_timer) &&
1540 del_timer(&transport->T3_rtx_timer)) {
1541 sctp_transport_put(transport);
1543 } else if (restart_timer) {
1544 if (!mod_timer(&transport->T3_rtx_timer,
1545 jiffies + transport->rto))
1546 sctp_transport_hold(transport);
1550 list_splice(&tlist, transmitted_queue);
1553 /* Mark chunks as missing and consequently may get retransmitted. */
1554 static void sctp_mark_missing(struct sctp_outq *q,
1555 struct list_head *transmitted_queue,
1556 struct sctp_transport *transport,
1557 __u32 highest_new_tsn_in_sack,
1558 int count_of_newacks)
1560 struct sctp_chunk *chunk;
1561 struct list_head *pos;
1562 __u32 tsn;
1563 char do_fast_retransmit = 0;
1564 struct sctp_transport *primary = q->asoc->peer.primary_path;
1566 list_for_each(pos, transmitted_queue) {
1568 chunk = list_entry(pos, struct sctp_chunk, transmitted_list);
1569 tsn = ntohl(chunk->subh.data_hdr->tsn);
1571 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all
1572 * 'Unacknowledged TSN's', if the TSN number of an
1573 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack'
1574 * value, increment the 'TSN.Missing.Report' count on that
1575 * chunk if it has NOT been fast retransmitted or marked for
1576 * fast retransmit already.
1578 if (!chunk->fast_retransmit &&
1579 !chunk->tsn_gap_acked &&
1580 TSN_lt(tsn, highest_new_tsn_in_sack)) {
1582 /* SFR-CACC may require us to skip marking
1583 * this chunk as missing.
1585 if (!transport || !sctp_cacc_skip(primary, transport,
1586 count_of_newacks, tsn)) {
1587 chunk->tsn_missing_report++;
1589 SCTP_DEBUG_PRINTK(
1590 "%s: TSN 0x%x missing counter: %d\n",
1591 __FUNCTION__, tsn,
1592 chunk->tsn_missing_report);
1596 * M4) If any DATA chunk is found to have a
1597 * 'TSN.Missing.Report'
1598 * value larger than or equal to 3, mark that chunk for
1599 * retransmission and start the fast retransmit procedure.
1602 if (chunk->tsn_missing_report >= 3) {
1603 chunk->fast_retransmit = 1;
1604 do_fast_retransmit = 1;
1608 if (transport) {
1609 if (do_fast_retransmit)
1610 sctp_retransmit(q, transport, SCTP_RTXR_FAST_RTX);
1612 SCTP_DEBUG_PRINTK("%s: transport: %p, cwnd: %d, "
1613 "ssthresh: %d, flight_size: %d, pba: %d\n",
1614 __FUNCTION__, transport, transport->cwnd,
1615 transport->ssthresh, transport->flight_size,
1616 transport->partial_bytes_acked);
1620 /* Is the given TSN acked by this packet? */
1621 static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn)
1623 int i;
1624 sctp_sack_variable_t *frags;
1625 __u16 gap;
1626 __u32 ctsn = ntohl(sack->cum_tsn_ack);
1628 if (TSN_lte(tsn, ctsn))
1629 goto pass;
1631 /* 3.3.4 Selective Acknowledgement (SACK) (3):
1633 * Gap Ack Blocks:
1634 * These fields contain the Gap Ack Blocks. They are repeated
1635 * for each Gap Ack Block up to the number of Gap Ack Blocks
1636 * defined in the Number of Gap Ack Blocks field. All DATA
1637 * chunks with TSNs greater than or equal to (Cumulative TSN
1638 * Ack + Gap Ack Block Start) and less than or equal to
1639 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack
1640 * Block are assumed to have been received correctly.
1643 frags = sack->variable;
1644 gap = tsn - ctsn;
1645 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); ++i) {
1646 if (TSN_lte(ntohs(frags[i].gab.start), gap) &&
1647 TSN_lte(gap, ntohs(frags[i].gab.end)))
1648 goto pass;
1651 return 0;
1652 pass:
1653 return 1;
1656 static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip *skiplist,
1657 int nskips, __be16 stream)
1659 int i;
1661 for (i = 0; i < nskips; i++) {
1662 if (skiplist[i].stream == stream)
1663 return i;
1665 return i;
1668 /* Create and add a fwdtsn chunk to the outq's control queue if needed. */
1669 static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 ctsn)
1671 struct sctp_association *asoc = q->asoc;
1672 struct sctp_chunk *ftsn_chunk = NULL;
1673 struct sctp_fwdtsn_skip ftsn_skip_arr[10];
1674 int nskips = 0;
1675 int skip_pos = 0;
1676 __u32 tsn;
1677 struct sctp_chunk *chunk;
1678 struct list_head *lchunk, *temp;
1680 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the
1681 * received SACK.
1683 * If (Advanced.Peer.Ack.Point < SackCumAck), then update
1684 * Advanced.Peer.Ack.Point to be equal to SackCumAck.
1686 if (TSN_lt(asoc->adv_peer_ack_point, ctsn))
1687 asoc->adv_peer_ack_point = ctsn;
1689 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point"
1690 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as
1691 * the chunk next in the out-queue space is marked as "abandoned" as
1692 * shown in the following example:
1694 * Assuming that a SACK arrived with the Cumulative TSN ACK 102
1695 * and the Advanced.Peer.Ack.Point is updated to this value:
1697 * out-queue at the end of ==> out-queue after Adv.Ack.Point
1698 * normal SACK processing local advancement
1699 * ... ...
1700 * Adv.Ack.Pt-> 102 acked 102 acked
1701 * 103 abandoned 103 abandoned
1702 * 104 abandoned Adv.Ack.P-> 104 abandoned
1703 * 105 105
1704 * 106 acked 106 acked
1705 * ... ...
1707 * In this example, the data sender successfully advanced the
1708 * "Advanced.Peer.Ack.Point" from 102 to 104 locally.
1710 list_for_each_safe(lchunk, temp, &q->abandoned) {
1711 chunk = list_entry(lchunk, struct sctp_chunk,
1712 transmitted_list);
1713 tsn = ntohl(chunk->subh.data_hdr->tsn);
1715 /* Remove any chunks in the abandoned queue that are acked by
1716 * the ctsn.
1718 if (TSN_lte(tsn, ctsn)) {
1719 list_del_init(lchunk);
1720 sctp_chunk_free(chunk);
1721 } else {
1722 if (TSN_lte(tsn, asoc->adv_peer_ack_point+1)) {
1723 asoc->adv_peer_ack_point = tsn;
1724 if (chunk->chunk_hdr->flags &
1725 SCTP_DATA_UNORDERED)
1726 continue;
1727 skip_pos = sctp_get_skip_pos(&ftsn_skip_arr[0],
1728 nskips,
1729 chunk->subh.data_hdr->stream);
1730 ftsn_skip_arr[skip_pos].stream =
1731 chunk->subh.data_hdr->stream;
1732 ftsn_skip_arr[skip_pos].ssn =
1733 chunk->subh.data_hdr->ssn;
1734 if (skip_pos == nskips)
1735 nskips++;
1736 if (nskips == 10)
1737 break;
1738 } else
1739 break;
1743 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point"
1744 * is greater than the Cumulative TSN ACK carried in the received
1745 * SACK, the data sender MUST send the data receiver a FORWARD TSN
1746 * chunk containing the latest value of the
1747 * "Advanced.Peer.Ack.Point".
1749 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD
1750 * list each stream and sequence number in the forwarded TSN. This
1751 * information will enable the receiver to easily find any
1752 * stranded TSN's waiting on stream reorder queues. Each stream
1753 * SHOULD only be reported once; this means that if multiple
1754 * abandoned messages occur in the same stream then only the
1755 * highest abandoned stream sequence number is reported. If the
1756 * total size of the FORWARD TSN does NOT fit in a single MTU then
1757 * the sender of the FORWARD TSN SHOULD lower the
1758 * Advanced.Peer.Ack.Point to the last TSN that will fit in a
1759 * single MTU.
1761 if (asoc->adv_peer_ack_point > ctsn)
1762 ftsn_chunk = sctp_make_fwdtsn(asoc, asoc->adv_peer_ack_point,
1763 nskips, &ftsn_skip_arr[0]);
1765 if (ftsn_chunk) {
1766 list_add_tail(&ftsn_chunk->list, &q->control_chunk_list);
1767 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);