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)
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
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>
53 #include <linux/slab.h>
54 #include <net/sock.h> /* For skb_set_owner_w */
56 #include <net/sctp/sctp.h>
57 #include <net/sctp/sm.h>
59 /* Declare internal functions here. */
60 static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn);
61 static void sctp_check_transmitted(struct sctp_outq *q,
62 struct list_head *transmitted_queue,
63 struct sctp_transport *transport,
64 struct sctp_sackhdr *sack,
65 __u32 highest_new_tsn);
67 static void sctp_mark_missing(struct sctp_outq *q,
68 struct list_head *transmitted_queue,
69 struct sctp_transport *transport,
70 __u32 highest_new_tsn,
71 int count_of_newacks);
73 static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 sack_ctsn);
75 static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout);
77 /* Add data to the front of the queue. */
78 static inline void sctp_outq_head_data(struct sctp_outq *q,
79 struct sctp_chunk *ch)
81 list_add(&ch->list, &q->out_chunk_list);
82 q->out_qlen += ch->skb->len;
86 /* Take data from the front of the queue. */
87 static inline struct sctp_chunk *sctp_outq_dequeue_data(struct sctp_outq *q)
89 struct sctp_chunk *ch = NULL;
91 if (!list_empty(&q->out_chunk_list)) {
92 struct list_head *entry = q->out_chunk_list.next;
94 ch = list_entry(entry, struct sctp_chunk, list);
96 q->out_qlen -= ch->skb->len;
100 /* Add data chunk to the end of the queue. */
101 static inline void sctp_outq_tail_data(struct sctp_outq *q,
102 struct sctp_chunk *ch)
104 list_add_tail(&ch->list, &q->out_chunk_list);
105 q->out_qlen += ch->skb->len;
110 * SFR-CACC algorithm:
111 * D) If count_of_newacks is greater than or equal to 2
112 * and t was not sent to the current primary then the
113 * sender MUST NOT increment missing report count for t.
115 static inline int sctp_cacc_skip_3_1_d(struct sctp_transport *primary,
116 struct sctp_transport *transport,
117 int count_of_newacks)
119 if (count_of_newacks >=2 && transport != primary)
125 * SFR-CACC algorithm:
126 * F) If count_of_newacks is less than 2, let d be the
127 * destination to which t was sent. If cacc_saw_newack
128 * is 0 for destination d, then the sender MUST NOT
129 * increment missing report count for t.
131 static inline int sctp_cacc_skip_3_1_f(struct sctp_transport *transport,
132 int count_of_newacks)
134 if (count_of_newacks < 2 && !transport->cacc.cacc_saw_newack)
140 * SFR-CACC algorithm:
141 * 3.1) If CYCLING_CHANGEOVER is 0, the sender SHOULD
142 * execute steps C, D, F.
144 * C has been implemented in sctp_outq_sack
146 static inline int sctp_cacc_skip_3_1(struct sctp_transport *primary,
147 struct sctp_transport *transport,
148 int count_of_newacks)
150 if (!primary->cacc.cycling_changeover) {
151 if (sctp_cacc_skip_3_1_d(primary, transport, count_of_newacks))
153 if (sctp_cacc_skip_3_1_f(transport, count_of_newacks))
161 * SFR-CACC algorithm:
162 * 3.2) Else if CYCLING_CHANGEOVER is 1, and t is less
163 * than next_tsn_at_change of the current primary, then
164 * the sender MUST NOT increment missing report count
167 static inline int sctp_cacc_skip_3_2(struct sctp_transport *primary, __u32 tsn)
169 if (primary->cacc.cycling_changeover &&
170 TSN_lt(tsn, primary->cacc.next_tsn_at_change))
176 * SFR-CACC algorithm:
177 * 3) If the missing report count for TSN t is to be
178 * incremented according to [RFC2960] and
179 * [SCTP_STEWART-2002], and CHANGEOVER_ACTIVE is set,
180 * then the sender MUST futher execute steps 3.1 and
181 * 3.2 to determine if the missing report count for
182 * TSN t SHOULD NOT be incremented.
184 * 3.3) If 3.1 and 3.2 do not dictate that the missing
185 * report count for t should not be incremented, then
186 * the sender SOULD increment missing report count for
187 * t (according to [RFC2960] and [SCTP_STEWART_2002]).
189 static inline int sctp_cacc_skip(struct sctp_transport *primary,
190 struct sctp_transport *transport,
191 int count_of_newacks,
194 if (primary->cacc.changeover_active &&
195 (sctp_cacc_skip_3_1(primary, transport, count_of_newacks) ||
196 sctp_cacc_skip_3_2(primary, tsn)))
201 /* Initialize an existing sctp_outq. This does the boring stuff.
202 * You still need to define handlers if you really want to DO
203 * something with this structure...
205 void sctp_outq_init(struct sctp_association *asoc, struct sctp_outq *q)
208 INIT_LIST_HEAD(&q->out_chunk_list);
209 INIT_LIST_HEAD(&q->control_chunk_list);
210 INIT_LIST_HEAD(&q->retransmit);
211 INIT_LIST_HEAD(&q->sacked);
212 INIT_LIST_HEAD(&q->abandoned);
215 q->outstanding_bytes = 0;
223 /* Free the outqueue structure and any related pending chunks.
225 void sctp_outq_teardown(struct sctp_outq *q)
227 struct sctp_transport *transport;
228 struct list_head *lchunk, *temp;
229 struct sctp_chunk *chunk, *tmp;
231 /* Throw away unacknowledged chunks. */
232 list_for_each_entry(transport, &q->asoc->peer.transport_addr_list,
234 while ((lchunk = sctp_list_dequeue(&transport->transmitted)) != NULL) {
235 chunk = list_entry(lchunk, struct sctp_chunk,
237 /* Mark as part of a failed message. */
238 sctp_chunk_fail(chunk, q->error);
239 sctp_chunk_free(chunk);
243 /* Throw away chunks that have been gap ACKed. */
244 list_for_each_safe(lchunk, temp, &q->sacked) {
245 list_del_init(lchunk);
246 chunk = list_entry(lchunk, struct sctp_chunk,
248 sctp_chunk_fail(chunk, q->error);
249 sctp_chunk_free(chunk);
252 /* Throw away any chunks in the retransmit queue. */
253 list_for_each_safe(lchunk, temp, &q->retransmit) {
254 list_del_init(lchunk);
255 chunk = list_entry(lchunk, struct sctp_chunk,
257 sctp_chunk_fail(chunk, q->error);
258 sctp_chunk_free(chunk);
261 /* Throw away any chunks that are in the abandoned queue. */
262 list_for_each_safe(lchunk, temp, &q->abandoned) {
263 list_del_init(lchunk);
264 chunk = list_entry(lchunk, struct sctp_chunk,
266 sctp_chunk_fail(chunk, q->error);
267 sctp_chunk_free(chunk);
270 /* Throw away any leftover data chunks. */
271 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) {
273 /* Mark as send failure. */
274 sctp_chunk_fail(chunk, q->error);
275 sctp_chunk_free(chunk);
280 /* Throw away any leftover control chunks. */
281 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) {
282 list_del_init(&chunk->list);
283 sctp_chunk_free(chunk);
287 /* Free the outqueue structure and any related pending chunks. */
288 void sctp_outq_free(struct sctp_outq *q)
290 /* Throw away leftover chunks. */
291 sctp_outq_teardown(q);
293 /* If we were kmalloc()'d, free the memory. */
298 /* Put a new chunk in an sctp_outq. */
299 int sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk)
303 SCTP_DEBUG_PRINTK("sctp_outq_tail(%p, %p[%s])\n",
304 q, chunk, chunk && chunk->chunk_hdr ?
305 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type))
308 /* If it is data, queue it up, otherwise, send it
311 if (sctp_chunk_is_data(chunk)) {
312 /* Is it OK to queue data chunks? */
313 /* From 9. Termination of Association
315 * When either endpoint performs a shutdown, the
316 * association on each peer will stop accepting new
317 * data from its user and only deliver data in queue
318 * at the time of sending or receiving the SHUTDOWN
321 switch (q->asoc->state) {
322 case SCTP_STATE_EMPTY:
323 case SCTP_STATE_CLOSED:
324 case SCTP_STATE_SHUTDOWN_PENDING:
325 case SCTP_STATE_SHUTDOWN_SENT:
326 case SCTP_STATE_SHUTDOWN_RECEIVED:
327 case SCTP_STATE_SHUTDOWN_ACK_SENT:
328 /* Cannot send after transport endpoint shutdown */
333 SCTP_DEBUG_PRINTK("outqueueing (%p, %p[%s])\n",
334 q, chunk, chunk && chunk->chunk_hdr ?
335 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type))
338 sctp_outq_tail_data(q, chunk);
339 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED)
340 SCTP_INC_STATS(SCTP_MIB_OUTUNORDERCHUNKS);
342 SCTP_INC_STATS(SCTP_MIB_OUTORDERCHUNKS);
347 list_add_tail(&chunk->list, &q->control_chunk_list);
348 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
355 error = sctp_outq_flush(q, 0);
360 /* Insert a chunk into the sorted list based on the TSNs. The retransmit list
361 * and the abandoned list are in ascending order.
363 static void sctp_insert_list(struct list_head *head, struct list_head *new)
365 struct list_head *pos;
366 struct sctp_chunk *nchunk, *lchunk;
370 nchunk = list_entry(new, struct sctp_chunk, transmitted_list);
371 ntsn = ntohl(nchunk->subh.data_hdr->tsn);
373 list_for_each(pos, head) {
374 lchunk = list_entry(pos, struct sctp_chunk, transmitted_list);
375 ltsn = ntohl(lchunk->subh.data_hdr->tsn);
376 if (TSN_lt(ntsn, ltsn)) {
377 list_add(new, pos->prev);
383 list_add_tail(new, head);
386 /* Mark all the eligible packets on a transport for retransmission. */
387 void sctp_retransmit_mark(struct sctp_outq *q,
388 struct sctp_transport *transport,
391 struct list_head *lchunk, *ltemp;
392 struct sctp_chunk *chunk;
394 /* Walk through the specified transmitted queue. */
395 list_for_each_safe(lchunk, ltemp, &transport->transmitted) {
396 chunk = list_entry(lchunk, struct sctp_chunk,
399 /* If the chunk is abandoned, move it to abandoned list. */
400 if (sctp_chunk_abandoned(chunk)) {
401 list_del_init(lchunk);
402 sctp_insert_list(&q->abandoned, lchunk);
404 /* If this chunk has not been previousely acked,
405 * stop considering it 'outstanding'. Our peer
406 * will most likely never see it since it will
407 * not be retransmitted
409 if (!chunk->tsn_gap_acked) {
410 if (chunk->transport)
411 chunk->transport->flight_size -=
412 sctp_data_size(chunk);
413 q->outstanding_bytes -= sctp_data_size(chunk);
414 q->asoc->peer.rwnd += (sctp_data_size(chunk) +
415 sizeof(struct sk_buff));
420 /* If we are doing retransmission due to a timeout or pmtu
421 * discovery, only the chunks that are not yet acked should
422 * be added to the retransmit queue.
424 if ((reason == SCTP_RTXR_FAST_RTX &&
425 (chunk->fast_retransmit == SCTP_NEED_FRTX)) ||
426 (reason != SCTP_RTXR_FAST_RTX && !chunk->tsn_gap_acked)) {
427 /* RFC 2960 6.2.1 Processing a Received SACK
429 * C) Any time a DATA chunk is marked for
430 * retransmission (via either T3-rtx timer expiration
431 * (Section 6.3.3) or via fast retransmit
432 * (Section 7.2.4)), add the data size of those
433 * chunks to the rwnd.
435 q->asoc->peer.rwnd += (sctp_data_size(chunk) +
436 sizeof(struct sk_buff));
437 q->outstanding_bytes -= sctp_data_size(chunk);
438 if (chunk->transport)
439 transport->flight_size -= sctp_data_size(chunk);
441 /* sctpimpguide-05 Section 2.8.2
442 * M5) If a T3-rtx timer expires, the
443 * 'TSN.Missing.Report' of all affected TSNs is set
446 chunk->tsn_missing_report = 0;
448 /* If a chunk that is being used for RTT measurement
449 * has to be retransmitted, we cannot use this chunk
450 * anymore for RTT measurements. Reset rto_pending so
451 * that a new RTT measurement is started when a new
452 * data chunk is sent.
454 if (chunk->rtt_in_progress) {
455 chunk->rtt_in_progress = 0;
456 transport->rto_pending = 0;
459 /* Move the chunk to the retransmit queue. The chunks
460 * on the retransmit queue are always kept in order.
462 list_del_init(lchunk);
463 sctp_insert_list(&q->retransmit, lchunk);
467 SCTP_DEBUG_PRINTK("%s: transport: %p, reason: %d, "
468 "cwnd: %d, ssthresh: %d, flight_size: %d, "
469 "pba: %d\n", __func__,
471 transport->cwnd, transport->ssthresh,
472 transport->flight_size,
473 transport->partial_bytes_acked);
477 /* Mark all the eligible packets on a transport for retransmission and force
480 void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
481 sctp_retransmit_reason_t reason)
486 case SCTP_RTXR_T3_RTX:
487 SCTP_INC_STATS(SCTP_MIB_T3_RETRANSMITS);
488 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_T3_RTX);
489 /* Update the retran path if the T3-rtx timer has expired for
490 * the current retran path.
492 if (transport == transport->asoc->peer.retran_path)
493 sctp_assoc_update_retran_path(transport->asoc);
494 transport->asoc->rtx_data_chunks +=
495 transport->asoc->unack_data;
497 case SCTP_RTXR_FAST_RTX:
498 SCTP_INC_STATS(SCTP_MIB_FAST_RETRANSMITS);
499 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_FAST_RTX);
502 case SCTP_RTXR_PMTUD:
503 SCTP_INC_STATS(SCTP_MIB_PMTUD_RETRANSMITS);
505 case SCTP_RTXR_T1_RTX:
506 SCTP_INC_STATS(SCTP_MIB_T1_RETRANSMITS);
507 transport->asoc->init_retries++;
513 sctp_retransmit_mark(q, transport, reason);
515 /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination,
516 * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by
517 * following the procedures outlined in C1 - C5.
519 if (reason == SCTP_RTXR_T3_RTX)
520 sctp_generate_fwdtsn(q, q->asoc->ctsn_ack_point);
522 /* Flush the queues only on timeout, since fast_rtx is only
523 * triggered during sack processing and the queue
524 * will be flushed at the end.
526 if (reason != SCTP_RTXR_FAST_RTX)
527 error = sctp_outq_flush(q, /* rtx_timeout */ 1);
530 q->asoc->base.sk->sk_err = -error;
534 * Transmit DATA chunks on the retransmit queue. Upon return from
535 * sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which
536 * need to be transmitted by the caller.
537 * We assume that pkt->transport has already been set.
539 * The return value is a normal kernel error return value.
541 static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
542 int rtx_timeout, int *start_timer)
544 struct list_head *lqueue;
545 struct sctp_transport *transport = pkt->transport;
547 struct sctp_chunk *chunk, *chunk1;
548 struct sctp_association *asoc;
555 lqueue = &q->retransmit;
556 fast_rtx = q->fast_rtx;
558 /* This loop handles time-out retransmissions, fast retransmissions,
559 * and retransmissions due to opening of whindow.
561 * RFC 2960 6.3.3 Handle T3-rtx Expiration
563 * E3) Determine how many of the earliest (i.e., lowest TSN)
564 * outstanding DATA chunks for the address for which the
565 * T3-rtx has expired will fit into a single packet, subject
566 * to the MTU constraint for the path corresponding to the
567 * destination transport address to which the retransmission
568 * is being sent (this may be different from the address for
569 * which the timer expires [see Section 6.4]). Call this value
570 * K. Bundle and retransmit those K DATA chunks in a single
571 * packet to the destination endpoint.
573 * [Just to be painfully clear, if we are retransmitting
574 * because a timeout just happened, we should send only ONE
575 * packet of retransmitted data.]
577 * For fast retransmissions we also send only ONE packet. However,
578 * if we are just flushing the queue due to open window, we'll
579 * try to send as much as possible.
581 list_for_each_entry_safe(chunk, chunk1, lqueue, transmitted_list) {
583 /* Make sure that Gap Acked TSNs are not retransmitted. A
584 * simple approach is just to move such TSNs out of the
585 * way and into a 'transmitted' queue and skip to the
588 if (chunk->tsn_gap_acked) {
589 list_del(&chunk->transmitted_list);
590 list_add_tail(&chunk->transmitted_list,
591 &transport->transmitted);
595 /* If we are doing fast retransmit, ignore non-fast_rtransmit
598 if (fast_rtx && !chunk->fast_retransmit)
602 /* Attempt to append this chunk to the packet. */
603 status = sctp_packet_append_chunk(pkt, chunk);
606 case SCTP_XMIT_PMTU_FULL:
607 if (!pkt->has_data && !pkt->has_cookie_echo) {
608 /* If this packet did not contain DATA then
609 * retransmission did not happen, so do it
610 * again. We'll ignore the error here since
611 * control chunks are already freed so there
612 * is nothing we can do.
614 sctp_packet_transmit(pkt);
618 /* Send this packet. */
619 error = sctp_packet_transmit(pkt);
621 /* If we are retransmitting, we should only
622 * send a single packet.
624 if (rtx_timeout || fast_rtx)
627 /* Bundle next chunk in the next round. */
630 case SCTP_XMIT_RWND_FULL:
631 /* Send this packet. */
632 error = sctp_packet_transmit(pkt);
634 /* Stop sending DATA as there is no more room
640 case SCTP_XMIT_NAGLE_DELAY:
641 /* Send this packet. */
642 error = sctp_packet_transmit(pkt);
644 /* Stop sending DATA because of nagle delay. */
649 /* The append was successful, so add this chunk to
650 * the transmitted list.
652 list_del(&chunk->transmitted_list);
653 list_add_tail(&chunk->transmitted_list,
654 &transport->transmitted);
656 /* Mark the chunk as ineligible for fast retransmit
657 * after it is retransmitted.
659 if (chunk->fast_retransmit == SCTP_NEED_FRTX)
660 chunk->fast_retransmit = SCTP_DONT_FRTX;
662 /* Force start T3-rtx timer when fast retransmitting
663 * the earliest outstanding TSN
665 if (!timer && fast_rtx &&
666 ntohl(chunk->subh.data_hdr->tsn) ==
667 asoc->ctsn_ack_point + 1)
674 /* Set the timer if there were no errors */
675 if (!error && !timer)
682 /* If we are here due to a retransmit timeout or a fast
683 * retransmit and if there are any chunks left in the retransmit
684 * queue that could not fit in the PMTU sized packet, they need
685 * to be marked as ineligible for a subsequent fast retransmit.
687 if (rtx_timeout || fast_rtx) {
688 list_for_each_entry(chunk1, lqueue, transmitted_list) {
689 if (chunk1->fast_retransmit == SCTP_NEED_FRTX)
690 chunk1->fast_retransmit = SCTP_DONT_FRTX;
694 *start_timer = timer;
696 /* Clear fast retransmit hint */
703 /* Cork the outqueue so queued chunks are really queued. */
704 int sctp_outq_uncork(struct sctp_outq *q)
709 error = sctp_outq_flush(q, 0);
715 * Try to flush an outqueue.
717 * Description: Send everything in q which we legally can, subject to
718 * congestion limitations.
719 * * Note: This function can be called from multiple contexts so appropriate
720 * locking concerns must be made. Today we use the sock lock to protect
723 static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout)
725 struct sctp_packet *packet;
726 struct sctp_packet singleton;
727 struct sctp_association *asoc = q->asoc;
728 __u16 sport = asoc->base.bind_addr.port;
729 __u16 dport = asoc->peer.port;
730 __u32 vtag = asoc->peer.i.init_tag;
731 struct sctp_transport *transport = NULL;
732 struct sctp_transport *new_transport;
733 struct sctp_chunk *chunk, *tmp;
739 /* These transports have chunks to send. */
740 struct list_head transport_list;
741 struct list_head *ltransport;
743 INIT_LIST_HEAD(&transport_list);
749 * When bundling control chunks with DATA chunks, an
750 * endpoint MUST place control chunks first in the outbound
751 * SCTP packet. The transmitter MUST transmit DATA chunks
752 * within a SCTP packet in increasing order of TSN.
756 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) {
757 list_del_init(&chunk->list);
759 /* Pick the right transport to use. */
760 new_transport = chunk->transport;
762 if (!new_transport) {
764 * If we have a prior transport pointer, see if
765 * the destination address of the chunk
766 * matches the destination address of the
767 * current transport. If not a match, then
768 * try to look up the transport with a given
769 * destination address. We do this because
770 * after processing ASCONFs, we may have new
771 * transports created.
774 sctp_cmp_addr_exact(&chunk->dest,
776 new_transport = transport;
778 new_transport = sctp_assoc_lookup_paddr(asoc,
781 /* if we still don't have a new transport, then
782 * use the current active path.
785 new_transport = asoc->peer.active_path;
786 } else if ((new_transport->state == SCTP_INACTIVE) ||
787 (new_transport->state == SCTP_UNCONFIRMED)) {
788 /* If the chunk is Heartbeat or Heartbeat Ack,
789 * send it to chunk->transport, even if it's
792 * 3.3.6 Heartbeat Acknowledgement:
794 * A HEARTBEAT ACK is always sent to the source IP
795 * address of the IP datagram containing the
796 * HEARTBEAT chunk to which this ack is responding.
799 * ASCONF_ACKs also must be sent to the source.
801 if (chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT &&
802 chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT_ACK &&
803 chunk->chunk_hdr->type != SCTP_CID_ASCONF_ACK)
804 new_transport = asoc->peer.active_path;
807 /* Are we switching transports?
808 * Take care of transport locks.
810 if (new_transport != transport) {
811 transport = new_transport;
812 if (list_empty(&transport->send_ready)) {
813 list_add_tail(&transport->send_ready,
816 packet = &transport->packet;
817 sctp_packet_config(packet, vtag,
818 asoc->peer.ecn_capable);
821 switch (chunk->chunk_hdr->type) {
825 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN
826 * COMPLETE with any other chunks. [Send them immediately.]
829 case SCTP_CID_INIT_ACK:
830 case SCTP_CID_SHUTDOWN_COMPLETE:
831 sctp_packet_init(&singleton, transport, sport, dport);
832 sctp_packet_config(&singleton, vtag, 0);
833 sctp_packet_append_chunk(&singleton, chunk);
834 error = sctp_packet_transmit(&singleton);
840 if (sctp_test_T_bit(chunk)) {
841 packet->vtag = asoc->c.my_vtag;
843 /* The following chunks are "response" chunks, i.e.
844 * they are generated in response to something we
845 * received. If we are sending these, then we can
846 * send only 1 packet containing these chunks.
848 case SCTP_CID_HEARTBEAT_ACK:
849 case SCTP_CID_SHUTDOWN_ACK:
850 case SCTP_CID_COOKIE_ACK:
851 case SCTP_CID_COOKIE_ECHO:
853 case SCTP_CID_ECN_CWR:
854 case SCTP_CID_ASCONF_ACK:
859 case SCTP_CID_HEARTBEAT:
860 case SCTP_CID_SHUTDOWN:
861 case SCTP_CID_ECN_ECNE:
862 case SCTP_CID_ASCONF:
863 case SCTP_CID_FWD_TSN:
864 status = sctp_packet_transmit_chunk(packet, chunk,
866 if (status != SCTP_XMIT_OK) {
867 /* put the chunk back */
868 list_add(&chunk->list, &q->control_chunk_list);
869 } else if (chunk->chunk_hdr->type == SCTP_CID_FWD_TSN) {
870 /* PR-SCTP C5) If a FORWARD TSN is sent, the
871 * sender MUST assure that at least one T3-rtx
874 sctp_transport_reset_timers(transport, 0);
879 /* We built a chunk with an illegal type! */
884 /* Is it OK to send data chunks? */
885 switch (asoc->state) {
886 case SCTP_STATE_COOKIE_ECHOED:
887 /* Only allow bundling when this packet has a COOKIE-ECHO
890 if (!packet || !packet->has_cookie_echo)
894 case SCTP_STATE_ESTABLISHED:
895 case SCTP_STATE_SHUTDOWN_PENDING:
896 case SCTP_STATE_SHUTDOWN_RECEIVED:
898 * RFC 2960 6.1 Transmission of DATA Chunks
900 * C) When the time comes for the sender to transmit,
901 * before sending new DATA chunks, the sender MUST
902 * first transmit any outstanding DATA chunks which
903 * are marked for retransmission (limited by the
906 if (!list_empty(&q->retransmit)) {
907 if (transport == asoc->peer.retran_path)
910 /* Switch transports & prepare the packet. */
912 transport = asoc->peer.retran_path;
914 if (list_empty(&transport->send_ready)) {
915 list_add_tail(&transport->send_ready,
919 packet = &transport->packet;
920 sctp_packet_config(packet, vtag,
921 asoc->peer.ecn_capable);
923 error = sctp_outq_flush_rtx(q, packet,
924 rtx_timeout, &start_timer);
927 sctp_transport_reset_timers(transport,
930 /* This can happen on COOKIE-ECHO resend. Only
931 * one chunk can get bundled with a COOKIE-ECHO.
933 if (packet->has_cookie_echo)
936 /* Don't send new data if there is still data
937 * waiting to retransmit.
939 if (!list_empty(&q->retransmit))
943 /* Apply Max.Burst limitation to the current transport in
944 * case it will be used for new data. We are going to
945 * rest it before we return, but we want to apply the limit
946 * to the currently queued data.
949 sctp_transport_burst_limited(transport);
951 /* Finally, transmit new packets. */
952 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) {
953 /* RFC 2960 6.5 Every DATA chunk MUST carry a valid
956 if (chunk->sinfo.sinfo_stream >=
957 asoc->c.sinit_num_ostreams) {
959 /* Mark as failed send. */
960 sctp_chunk_fail(chunk, SCTP_ERROR_INV_STRM);
961 sctp_chunk_free(chunk);
965 /* Has this chunk expired? */
966 if (sctp_chunk_abandoned(chunk)) {
967 sctp_chunk_fail(chunk, 0);
968 sctp_chunk_free(chunk);
972 /* If there is a specified transport, use it.
973 * Otherwise, we want to use the active path.
975 new_transport = chunk->transport;
976 if (!new_transport ||
977 ((new_transport->state == SCTP_INACTIVE) ||
978 (new_transport->state == SCTP_UNCONFIRMED)))
979 new_transport = asoc->peer.active_path;
981 /* Change packets if necessary. */
982 if (new_transport != transport) {
983 transport = new_transport;
985 /* Schedule to have this transport's
988 if (list_empty(&transport->send_ready)) {
989 list_add_tail(&transport->send_ready,
993 packet = &transport->packet;
994 sctp_packet_config(packet, vtag,
995 asoc->peer.ecn_capable);
996 /* We've switched transports, so apply the
997 * Burst limit to the new transport.
999 sctp_transport_burst_limited(transport);
1002 SCTP_DEBUG_PRINTK("sctp_outq_flush(%p, %p[%s]), ",
1004 chunk && chunk->chunk_hdr ?
1005 sctp_cname(SCTP_ST_CHUNK(
1006 chunk->chunk_hdr->type))
1009 SCTP_DEBUG_PRINTK("TX TSN 0x%x skb->head "
1010 "%p skb->users %d.\n",
1011 ntohl(chunk->subh.data_hdr->tsn),
1012 chunk->skb ?chunk->skb->head : NULL,
1014 atomic_read(&chunk->skb->users) : -1);
1016 /* Add the chunk to the packet. */
1017 status = sctp_packet_transmit_chunk(packet, chunk, 0);
1020 case SCTP_XMIT_PMTU_FULL:
1021 case SCTP_XMIT_RWND_FULL:
1022 case SCTP_XMIT_NAGLE_DELAY:
1023 /* We could not append this chunk, so put
1024 * the chunk back on the output queue.
1026 SCTP_DEBUG_PRINTK("sctp_outq_flush: could "
1027 "not transmit TSN: 0x%x, status: %d\n",
1028 ntohl(chunk->subh.data_hdr->tsn),
1030 sctp_outq_head_data(q, chunk);
1031 goto sctp_flush_out;
1035 /* The sender is in the SHUTDOWN-PENDING state,
1036 * The sender MAY set the I-bit in the DATA
1039 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING)
1040 chunk->chunk_hdr->flags |= SCTP_DATA_SACK_IMM;
1048 /* BUG: We assume that the sctp_packet_transmit()
1049 * call below will succeed all the time and add the
1050 * chunk to the transmitted list and restart the
1052 * It is possible that the call can fail under OOM
1055 * Is this really a problem? Won't this behave
1058 list_add_tail(&chunk->transmitted_list,
1059 &transport->transmitted);
1061 sctp_transport_reset_timers(transport, 0);
1065 /* Only let one DATA chunk get bundled with a
1066 * COOKIE-ECHO chunk.
1068 if (packet->has_cookie_echo)
1069 goto sctp_flush_out;
1080 /* Before returning, examine all the transports touched in
1081 * this call. Right now, we bluntly force clear all the
1082 * transports. Things might change after we implement Nagle.
1083 * But such an examination is still required.
1087 while ((ltransport = sctp_list_dequeue(&transport_list)) != NULL ) {
1088 struct sctp_transport *t = list_entry(ltransport,
1089 struct sctp_transport,
1091 packet = &t->packet;
1092 if (!sctp_packet_empty(packet))
1093 error = sctp_packet_transmit(packet);
1095 /* Clear the burst limited state, if any */
1096 sctp_transport_burst_reset(t);
1102 /* Update unack_data based on the incoming SACK chunk */
1103 static void sctp_sack_update_unack_data(struct sctp_association *assoc,
1104 struct sctp_sackhdr *sack)
1106 sctp_sack_variable_t *frags;
1110 unack_data = assoc->next_tsn - assoc->ctsn_ack_point - 1;
1112 frags = sack->variable;
1113 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); i++) {
1114 unack_data -= ((ntohs(frags[i].gab.end) -
1115 ntohs(frags[i].gab.start) + 1));
1118 assoc->unack_data = unack_data;
1121 /* Return the highest new tsn that is acknowledged by the given SACK chunk. */
1122 static __u32 sctp_highest_new_tsn(struct sctp_sackhdr *sack,
1123 struct sctp_association *asoc)
1125 struct sctp_transport *transport;
1126 struct sctp_chunk *chunk;
1127 __u32 highest_new_tsn, tsn;
1128 struct list_head *transport_list = &asoc->peer.transport_addr_list;
1130 highest_new_tsn = ntohl(sack->cum_tsn_ack);
1132 list_for_each_entry(transport, transport_list, transports) {
1133 list_for_each_entry(chunk, &transport->transmitted,
1135 tsn = ntohl(chunk->subh.data_hdr->tsn);
1137 if (!chunk->tsn_gap_acked &&
1138 TSN_lt(highest_new_tsn, tsn) &&
1139 sctp_acked(sack, tsn))
1140 highest_new_tsn = tsn;
1144 return highest_new_tsn;
1147 /* This is where we REALLY process a SACK.
1149 * Process the SACK against the outqueue. Mostly, this just frees
1150 * things off the transmitted queue.
1152 int sctp_outq_sack(struct sctp_outq *q, struct sctp_sackhdr *sack)
1154 struct sctp_association *asoc = q->asoc;
1155 struct sctp_transport *transport;
1156 struct sctp_chunk *tchunk = NULL;
1157 struct list_head *lchunk, *transport_list, *temp;
1158 sctp_sack_variable_t *frags = sack->variable;
1159 __u32 sack_ctsn, ctsn, tsn;
1160 __u32 highest_tsn, highest_new_tsn;
1162 unsigned outstanding;
1163 struct sctp_transport *primary = asoc->peer.primary_path;
1164 int count_of_newacks = 0;
1167 /* Grab the association's destination address list. */
1168 transport_list = &asoc->peer.transport_addr_list;
1170 sack_ctsn = ntohl(sack->cum_tsn_ack);
1171 gap_ack_blocks = ntohs(sack->num_gap_ack_blocks);
1173 * SFR-CACC algorithm:
1174 * On receipt of a SACK the sender SHOULD execute the
1175 * following statements.
1177 * 1) If the cumulative ack in the SACK passes next tsn_at_change
1178 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be
1179 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for
1181 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE
1182 * is set the receiver of the SACK MUST take the following actions:
1184 * A) Initialize the cacc_saw_newack to 0 for all destination
1187 * Only bother if changeover_active is set. Otherwise, this is
1188 * totally suboptimal to do on every SACK.
1190 if (primary->cacc.changeover_active) {
1191 u8 clear_cycling = 0;
1193 if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) {
1194 primary->cacc.changeover_active = 0;
1198 if (clear_cycling || gap_ack_blocks) {
1199 list_for_each_entry(transport, transport_list,
1202 transport->cacc.cycling_changeover = 0;
1204 transport->cacc.cacc_saw_newack = 0;
1209 /* Get the highest TSN in the sack. */
1210 highest_tsn = sack_ctsn;
1212 highest_tsn += ntohs(frags[gap_ack_blocks - 1].gab.end);
1214 if (TSN_lt(asoc->highest_sacked, highest_tsn)) {
1215 highest_new_tsn = highest_tsn;
1216 asoc->highest_sacked = highest_tsn;
1218 highest_new_tsn = sctp_highest_new_tsn(sack, asoc);
1222 /* Run through the retransmit queue. Credit bytes received
1223 * and free those chunks that we can.
1225 sctp_check_transmitted(q, &q->retransmit, NULL, sack, highest_new_tsn);
1227 /* Run through the transmitted queue.
1228 * Credit bytes received and free those chunks which we can.
1230 * This is a MASSIVE candidate for optimization.
1232 list_for_each_entry(transport, transport_list, transports) {
1233 sctp_check_transmitted(q, &transport->transmitted,
1234 transport, sack, highest_new_tsn);
1236 * SFR-CACC algorithm:
1237 * C) Let count_of_newacks be the number of
1238 * destinations for which cacc_saw_newack is set.
1240 if (transport->cacc.cacc_saw_newack)
1241 count_of_newacks ++;
1244 if (gap_ack_blocks) {
1245 list_for_each_entry(transport, transport_list, transports)
1246 sctp_mark_missing(q, &transport->transmitted, transport,
1247 highest_new_tsn, count_of_newacks);
1250 /* Move the Cumulative TSN Ack Point if appropriate. */
1251 if (TSN_lt(asoc->ctsn_ack_point, sack_ctsn))
1252 asoc->ctsn_ack_point = sack_ctsn;
1254 /* Update unack_data field in the assoc. */
1255 sctp_sack_update_unack_data(asoc, sack);
1257 ctsn = asoc->ctsn_ack_point;
1259 /* Throw away stuff rotting on the sack queue. */
1260 list_for_each_safe(lchunk, temp, &q->sacked) {
1261 tchunk = list_entry(lchunk, struct sctp_chunk,
1263 tsn = ntohl(tchunk->subh.data_hdr->tsn);
1264 if (TSN_lte(tsn, ctsn)) {
1265 list_del_init(&tchunk->transmitted_list);
1266 sctp_chunk_free(tchunk);
1270 /* ii) Set rwnd equal to the newly received a_rwnd minus the
1271 * number of bytes still outstanding after processing the
1272 * Cumulative TSN Ack and the Gap Ack Blocks.
1275 sack_a_rwnd = ntohl(sack->a_rwnd);
1276 outstanding = q->outstanding_bytes;
1278 if (outstanding < sack_a_rwnd)
1279 sack_a_rwnd -= outstanding;
1283 asoc->peer.rwnd = sack_a_rwnd;
1285 sctp_generate_fwdtsn(q, sack_ctsn);
1287 SCTP_DEBUG_PRINTK("%s: sack Cumulative TSN Ack is 0x%x.\n",
1288 __func__, sack_ctsn);
1289 SCTP_DEBUG_PRINTK("%s: Cumulative TSN Ack of association, "
1290 "%p is 0x%x. Adv peer ack point: 0x%x\n",
1291 __func__, asoc, ctsn, asoc->adv_peer_ack_point);
1293 /* See if all chunks are acked.
1294 * Make sure the empty queue handler will get run later.
1296 q->empty = (list_empty(&q->out_chunk_list) &&
1297 list_empty(&q->retransmit));
1301 list_for_each_entry(transport, transport_list, transports) {
1302 q->empty = q->empty && list_empty(&transport->transmitted);
1307 SCTP_DEBUG_PRINTK("sack queue is empty.\n");
1312 /* Is the outqueue empty? */
1313 int sctp_outq_is_empty(const struct sctp_outq *q)
1318 /********************************************************************
1319 * 2nd Level Abstractions
1320 ********************************************************************/
1322 /* Go through a transport's transmitted list or the association's retransmit
1323 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked.
1324 * The retransmit list will not have an associated transport.
1326 * I added coherent debug information output. --xguo
1328 * Instead of printing 'sacked' or 'kept' for each TSN on the
1329 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5.
1330 * KEPT TSN6-TSN7, etc.
1332 static void sctp_check_transmitted(struct sctp_outq *q,
1333 struct list_head *transmitted_queue,
1334 struct sctp_transport *transport,
1335 struct sctp_sackhdr *sack,
1336 __u32 highest_new_tsn_in_sack)
1338 struct list_head *lchunk;
1339 struct sctp_chunk *tchunk;
1340 struct list_head tlist;
1344 __u8 restart_timer = 0;
1345 int bytes_acked = 0;
1346 int migrate_bytes = 0;
1348 /* These state variables are for coherent debug output. --xguo */
1351 __u32 dbg_ack_tsn = 0; /* An ACKed TSN range starts here... */
1352 __u32 dbg_last_ack_tsn = 0; /* ...and finishes here. */
1353 __u32 dbg_kept_tsn = 0; /* An un-ACKed range starts here... */
1354 __u32 dbg_last_kept_tsn = 0; /* ...and finishes here. */
1356 /* 0 : The last TSN was ACKed.
1357 * 1 : The last TSN was NOT ACKed (i.e. KEPT).
1358 * -1: We need to initialize.
1360 int dbg_prt_state = -1;
1361 #endif /* SCTP_DEBUG */
1363 sack_ctsn = ntohl(sack->cum_tsn_ack);
1365 INIT_LIST_HEAD(&tlist);
1367 /* The while loop will skip empty transmitted queues. */
1368 while (NULL != (lchunk = sctp_list_dequeue(transmitted_queue))) {
1369 tchunk = list_entry(lchunk, struct sctp_chunk,
1372 if (sctp_chunk_abandoned(tchunk)) {
1373 /* Move the chunk to abandoned list. */
1374 sctp_insert_list(&q->abandoned, lchunk);
1376 /* If this chunk has not been acked, stop
1377 * considering it as 'outstanding'.
1379 if (!tchunk->tsn_gap_acked) {
1380 if (tchunk->transport)
1381 tchunk->transport->flight_size -=
1382 sctp_data_size(tchunk);
1383 q->outstanding_bytes -= sctp_data_size(tchunk);
1388 tsn = ntohl(tchunk->subh.data_hdr->tsn);
1389 if (sctp_acked(sack, tsn)) {
1390 /* If this queue is the retransmit queue, the
1391 * retransmit timer has already reclaimed
1392 * the outstanding bytes for this chunk, so only
1393 * count bytes associated with a transport.
1396 /* If this chunk is being used for RTT
1397 * measurement, calculate the RTT and update
1398 * the RTO using this value.
1400 * 6.3.1 C5) Karn's algorithm: RTT measurements
1401 * MUST NOT be made using packets that were
1402 * retransmitted (and thus for which it is
1403 * ambiguous whether the reply was for the
1404 * first instance of the packet or a later
1407 if (!tchunk->tsn_gap_acked &&
1408 tchunk->rtt_in_progress) {
1409 tchunk->rtt_in_progress = 0;
1410 rtt = jiffies - tchunk->sent_at;
1411 sctp_transport_update_rto(transport,
1416 /* If the chunk hasn't been marked as ACKED,
1417 * mark it and account bytes_acked if the
1418 * chunk had a valid transport (it will not
1419 * have a transport if ASCONF had deleted it
1420 * while DATA was outstanding).
1422 if (!tchunk->tsn_gap_acked) {
1423 tchunk->tsn_gap_acked = 1;
1424 bytes_acked += sctp_data_size(tchunk);
1425 if (!tchunk->transport)
1426 migrate_bytes += sctp_data_size(tchunk);
1429 if (TSN_lte(tsn, sack_ctsn)) {
1430 /* RFC 2960 6.3.2 Retransmission Timer Rules
1432 * R3) Whenever a SACK is received
1433 * that acknowledges the DATA chunk
1434 * with the earliest outstanding TSN
1435 * for that address, restart T3-rtx
1436 * timer for that address with its
1441 if (!tchunk->tsn_gap_acked) {
1443 * SFR-CACC algorithm:
1444 * 2) If the SACK contains gap acks
1445 * and the flag CHANGEOVER_ACTIVE is
1446 * set the receiver of the SACK MUST
1447 * take the following action:
1449 * B) For each TSN t being acked that
1450 * has not been acked in any SACK so
1451 * far, set cacc_saw_newack to 1 for
1452 * the destination that the TSN was
1456 sack->num_gap_ack_blocks &&
1457 q->asoc->peer.primary_path->cacc.
1459 transport->cacc.cacc_saw_newack
1463 list_add_tail(&tchunk->transmitted_list,
1466 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2
1467 * M2) Each time a SACK arrives reporting
1468 * 'Stray DATA chunk(s)' record the highest TSN
1469 * reported as newly acknowledged, call this
1470 * value 'HighestTSNinSack'. A newly
1471 * acknowledged DATA chunk is one not
1472 * previously acknowledged in a SACK.
1474 * When the SCTP sender of data receives a SACK
1475 * chunk that acknowledges, for the first time,
1476 * the receipt of a DATA chunk, all the still
1477 * unacknowledged DATA chunks whose TSN is
1478 * older than that newly acknowledged DATA
1479 * chunk, are qualified as 'Stray DATA chunks'.
1481 list_add_tail(lchunk, &tlist);
1485 switch (dbg_prt_state) {
1486 case 0: /* last TSN was ACKed */
1487 if (dbg_last_ack_tsn + 1 == tsn) {
1488 /* This TSN belongs to the
1489 * current ACK range.
1494 if (dbg_last_ack_tsn != dbg_ack_tsn) {
1495 /* Display the end of the
1498 SCTP_DEBUG_PRINTK("-%08x",
1502 /* Start a new range. */
1503 SCTP_DEBUG_PRINTK(",%08x", tsn);
1507 case 1: /* The last TSN was NOT ACKed. */
1508 if (dbg_last_kept_tsn != dbg_kept_tsn) {
1509 /* Display the end of current range. */
1510 SCTP_DEBUG_PRINTK("-%08x",
1514 SCTP_DEBUG_PRINTK("\n");
1516 /* FALL THROUGH... */
1518 /* This is the first-ever TSN we examined. */
1519 /* Start a new range of ACK-ed TSNs. */
1520 SCTP_DEBUG_PRINTK("ACKed: %08x", tsn);
1525 dbg_last_ack_tsn = tsn;
1526 #endif /* SCTP_DEBUG */
1529 if (tchunk->tsn_gap_acked) {
1530 SCTP_DEBUG_PRINTK("%s: Receiver reneged on "
1534 tchunk->tsn_gap_acked = 0;
1536 if (tchunk->transport)
1537 bytes_acked -= sctp_data_size(tchunk);
1539 /* RFC 2960 6.3.2 Retransmission Timer Rules
1541 * R4) Whenever a SACK is received missing a
1542 * TSN that was previously acknowledged via a
1543 * Gap Ack Block, start T3-rtx for the
1544 * destination address to which the DATA
1545 * chunk was originally
1546 * transmitted if it is not already running.
1551 list_add_tail(lchunk, &tlist);
1554 /* See the above comments on ACK-ed TSNs. */
1555 switch (dbg_prt_state) {
1557 if (dbg_last_kept_tsn + 1 == tsn)
1560 if (dbg_last_kept_tsn != dbg_kept_tsn)
1561 SCTP_DEBUG_PRINTK("-%08x",
1564 SCTP_DEBUG_PRINTK(",%08x", tsn);
1569 if (dbg_last_ack_tsn != dbg_ack_tsn)
1570 SCTP_DEBUG_PRINTK("-%08x",
1572 SCTP_DEBUG_PRINTK("\n");
1574 /* FALL THROUGH... */
1576 SCTP_DEBUG_PRINTK("KEPT: %08x",tsn);
1581 dbg_last_kept_tsn = tsn;
1582 #endif /* SCTP_DEBUG */
1587 /* Finish off the last range, displaying its ending TSN. */
1588 switch (dbg_prt_state) {
1590 if (dbg_last_ack_tsn != dbg_ack_tsn) {
1591 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_ack_tsn);
1593 SCTP_DEBUG_PRINTK("\n");
1598 if (dbg_last_kept_tsn != dbg_kept_tsn) {
1599 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_kept_tsn);
1601 SCTP_DEBUG_PRINTK("\n");
1604 #endif /* SCTP_DEBUG */
1607 /* We may have counted DATA that was migrated
1608 * to this transport due to DEL-IP operation.
1609 * Subtract those bytes, since the were never
1610 * send on this transport and shouldn't be
1611 * credited to this transport.
1613 bytes_acked -= migrate_bytes;
1615 /* 8.2. When an outstanding TSN is acknowledged,
1616 * the endpoint shall clear the error counter of
1617 * the destination transport address to which the
1618 * DATA chunk was last sent.
1619 * The association's overall error counter is
1622 transport->error_count = 0;
1623 transport->asoc->overall_error_count = 0;
1625 /* Mark the destination transport address as
1626 * active if it is not so marked.
1628 if ((transport->state == SCTP_INACTIVE) ||
1629 (transport->state == SCTP_UNCONFIRMED)) {
1630 sctp_assoc_control_transport(
1634 SCTP_RECEIVED_SACK);
1637 sctp_transport_raise_cwnd(transport, sack_ctsn,
1640 transport->flight_size -= bytes_acked;
1641 if (transport->flight_size == 0)
1642 transport->partial_bytes_acked = 0;
1643 q->outstanding_bytes -= bytes_acked + migrate_bytes;
1645 /* RFC 2960 6.1, sctpimpguide-06 2.15.2
1646 * When a sender is doing zero window probing, it
1647 * should not timeout the association if it continues
1648 * to receive new packets from the receiver. The
1649 * reason is that the receiver MAY keep its window
1650 * closed for an indefinite time.
1651 * A sender is doing zero window probing when the
1652 * receiver's advertised window is zero, and there is
1653 * only one data chunk in flight to the receiver.
1655 if (!q->asoc->peer.rwnd &&
1656 !list_empty(&tlist) &&
1657 (sack_ctsn+2 == q->asoc->next_tsn)) {
1658 SCTP_DEBUG_PRINTK("%s: SACK received for zero "
1659 "window probe: %u\n",
1660 __func__, sack_ctsn);
1661 q->asoc->overall_error_count = 0;
1662 transport->error_count = 0;
1666 /* RFC 2960 6.3.2 Retransmission Timer Rules
1668 * R2) Whenever all outstanding data sent to an address have
1669 * been acknowledged, turn off the T3-rtx timer of that
1672 if (!transport->flight_size) {
1673 if (timer_pending(&transport->T3_rtx_timer) &&
1674 del_timer(&transport->T3_rtx_timer)) {
1675 sctp_transport_put(transport);
1677 } else if (restart_timer) {
1678 if (!mod_timer(&transport->T3_rtx_timer,
1679 jiffies + transport->rto))
1680 sctp_transport_hold(transport);
1684 list_splice(&tlist, transmitted_queue);
1687 /* Mark chunks as missing and consequently may get retransmitted. */
1688 static void sctp_mark_missing(struct sctp_outq *q,
1689 struct list_head *transmitted_queue,
1690 struct sctp_transport *transport,
1691 __u32 highest_new_tsn_in_sack,
1692 int count_of_newacks)
1694 struct sctp_chunk *chunk;
1696 char do_fast_retransmit = 0;
1697 struct sctp_transport *primary = q->asoc->peer.primary_path;
1699 list_for_each_entry(chunk, transmitted_queue, transmitted_list) {
1701 tsn = ntohl(chunk->subh.data_hdr->tsn);
1703 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all
1704 * 'Unacknowledged TSN's', if the TSN number of an
1705 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack'
1706 * value, increment the 'TSN.Missing.Report' count on that
1707 * chunk if it has NOT been fast retransmitted or marked for
1708 * fast retransmit already.
1710 if (chunk->fast_retransmit == SCTP_CAN_FRTX &&
1711 !chunk->tsn_gap_acked &&
1712 TSN_lt(tsn, highest_new_tsn_in_sack)) {
1714 /* SFR-CACC may require us to skip marking
1715 * this chunk as missing.
1717 if (!transport || !sctp_cacc_skip(primary, transport,
1718 count_of_newacks, tsn)) {
1719 chunk->tsn_missing_report++;
1722 "%s: TSN 0x%x missing counter: %d\n",
1724 chunk->tsn_missing_report);
1728 * M4) If any DATA chunk is found to have a
1729 * 'TSN.Missing.Report'
1730 * value larger than or equal to 3, mark that chunk for
1731 * retransmission and start the fast retransmit procedure.
1734 if (chunk->tsn_missing_report >= 3) {
1735 chunk->fast_retransmit = SCTP_NEED_FRTX;
1736 do_fast_retransmit = 1;
1741 if (do_fast_retransmit)
1742 sctp_retransmit(q, transport, SCTP_RTXR_FAST_RTX);
1744 SCTP_DEBUG_PRINTK("%s: transport: %p, cwnd: %d, "
1745 "ssthresh: %d, flight_size: %d, pba: %d\n",
1746 __func__, transport, transport->cwnd,
1747 transport->ssthresh, transport->flight_size,
1748 transport->partial_bytes_acked);
1752 /* Is the given TSN acked by this packet? */
1753 static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn)
1756 sctp_sack_variable_t *frags;
1758 __u32 ctsn = ntohl(sack->cum_tsn_ack);
1760 if (TSN_lte(tsn, ctsn))
1763 /* 3.3.4 Selective Acknowledgement (SACK) (3):
1766 * These fields contain the Gap Ack Blocks. They are repeated
1767 * for each Gap Ack Block up to the number of Gap Ack Blocks
1768 * defined in the Number of Gap Ack Blocks field. All DATA
1769 * chunks with TSNs greater than or equal to (Cumulative TSN
1770 * Ack + Gap Ack Block Start) and less than or equal to
1771 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack
1772 * Block are assumed to have been received correctly.
1775 frags = sack->variable;
1777 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); ++i) {
1778 if (TSN_lte(ntohs(frags[i].gab.start), gap) &&
1779 TSN_lte(gap, ntohs(frags[i].gab.end)))
1788 static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip *skiplist,
1789 int nskips, __be16 stream)
1793 for (i = 0; i < nskips; i++) {
1794 if (skiplist[i].stream == stream)
1800 /* Create and add a fwdtsn chunk to the outq's control queue if needed. */
1801 static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 ctsn)
1803 struct sctp_association *asoc = q->asoc;
1804 struct sctp_chunk *ftsn_chunk = NULL;
1805 struct sctp_fwdtsn_skip ftsn_skip_arr[10];
1809 struct sctp_chunk *chunk;
1810 struct list_head *lchunk, *temp;
1812 if (!asoc->peer.prsctp_capable)
1815 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the
1818 * If (Advanced.Peer.Ack.Point < SackCumAck), then update
1819 * Advanced.Peer.Ack.Point to be equal to SackCumAck.
1821 if (TSN_lt(asoc->adv_peer_ack_point, ctsn))
1822 asoc->adv_peer_ack_point = ctsn;
1824 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point"
1825 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as
1826 * the chunk next in the out-queue space is marked as "abandoned" as
1827 * shown in the following example:
1829 * Assuming that a SACK arrived with the Cumulative TSN ACK 102
1830 * and the Advanced.Peer.Ack.Point is updated to this value:
1832 * out-queue at the end of ==> out-queue after Adv.Ack.Point
1833 * normal SACK processing local advancement
1835 * Adv.Ack.Pt-> 102 acked 102 acked
1836 * 103 abandoned 103 abandoned
1837 * 104 abandoned Adv.Ack.P-> 104 abandoned
1839 * 106 acked 106 acked
1842 * In this example, the data sender successfully advanced the
1843 * "Advanced.Peer.Ack.Point" from 102 to 104 locally.
1845 list_for_each_safe(lchunk, temp, &q->abandoned) {
1846 chunk = list_entry(lchunk, struct sctp_chunk,
1848 tsn = ntohl(chunk->subh.data_hdr->tsn);
1850 /* Remove any chunks in the abandoned queue that are acked by
1853 if (TSN_lte(tsn, ctsn)) {
1854 list_del_init(lchunk);
1855 sctp_chunk_free(chunk);
1857 if (TSN_lte(tsn, asoc->adv_peer_ack_point+1)) {
1858 asoc->adv_peer_ack_point = tsn;
1859 if (chunk->chunk_hdr->flags &
1860 SCTP_DATA_UNORDERED)
1862 skip_pos = sctp_get_skip_pos(&ftsn_skip_arr[0],
1864 chunk->subh.data_hdr->stream);
1865 ftsn_skip_arr[skip_pos].stream =
1866 chunk->subh.data_hdr->stream;
1867 ftsn_skip_arr[skip_pos].ssn =
1868 chunk->subh.data_hdr->ssn;
1869 if (skip_pos == nskips)
1878 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point"
1879 * is greater than the Cumulative TSN ACK carried in the received
1880 * SACK, the data sender MUST send the data receiver a FORWARD TSN
1881 * chunk containing the latest value of the
1882 * "Advanced.Peer.Ack.Point".
1884 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD
1885 * list each stream and sequence number in the forwarded TSN. This
1886 * information will enable the receiver to easily find any
1887 * stranded TSN's waiting on stream reorder queues. Each stream
1888 * SHOULD only be reported once; this means that if multiple
1889 * abandoned messages occur in the same stream then only the
1890 * highest abandoned stream sequence number is reported. If the
1891 * total size of the FORWARD TSN does NOT fit in a single MTU then
1892 * the sender of the FORWARD TSN SHOULD lower the
1893 * Advanced.Peer.Ack.Point to the last TSN that will fit in a
1896 if (asoc->adv_peer_ack_point > ctsn)
1897 ftsn_chunk = sctp_make_fwdtsn(asoc, asoc->adv_peer_ack_point,
1898 nskips, &ftsn_skip_arr[0]);
1901 list_add_tail(&ftsn_chunk->list, &q->control_chunk_list);
1902 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);