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 <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 static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout);
76 /* Add data to the front of the queue. */
77 static inline void sctp_outq_head_data(struct sctp_outq *q,
78 struct sctp_chunk *ch)
80 list_add(&ch->list, &q->out_chunk_list);
81 q->out_qlen += ch->skb->len;
85 /* Take data from the front of the queue. */
86 static inline struct sctp_chunk *sctp_outq_dequeue_data(struct sctp_outq *q)
88 struct sctp_chunk *ch = NULL;
90 if (!list_empty(&q->out_chunk_list)) {
91 struct list_head *entry = q->out_chunk_list.next;
93 ch = list_entry(entry, struct sctp_chunk, list);
95 q->out_qlen -= ch->skb->len;
99 /* Add data chunk to the end of the queue. */
100 static inline void sctp_outq_tail_data(struct sctp_outq *q,
101 struct sctp_chunk *ch)
103 list_add_tail(&ch->list, &q->out_chunk_list);
104 q->out_qlen += ch->skb->len;
109 * SFR-CACC algorithm:
110 * D) If count_of_newacks is greater than or equal to 2
111 * and t was not sent to the current primary then the
112 * sender MUST NOT increment missing report count for t.
114 static inline int sctp_cacc_skip_3_1_d(struct sctp_transport *primary,
115 struct sctp_transport *transport,
116 int count_of_newacks)
118 if (count_of_newacks >=2 && transport != primary)
124 * SFR-CACC algorithm:
125 * F) If count_of_newacks is less than 2, let d be the
126 * destination to which t was sent. If cacc_saw_newack
127 * is 0 for destination d, then the sender MUST NOT
128 * increment missing report count for t.
130 static inline int sctp_cacc_skip_3_1_f(struct sctp_transport *transport,
131 int count_of_newacks)
133 if (count_of_newacks < 2 && !transport->cacc.cacc_saw_newack)
139 * SFR-CACC algorithm:
140 * 3.1) If CYCLING_CHANGEOVER is 0, the sender SHOULD
141 * execute steps C, D, F.
143 * C has been implemented in sctp_outq_sack
145 static inline int sctp_cacc_skip_3_1(struct sctp_transport *primary,
146 struct sctp_transport *transport,
147 int count_of_newacks)
149 if (!primary->cacc.cycling_changeover) {
150 if (sctp_cacc_skip_3_1_d(primary, transport, count_of_newacks))
152 if (sctp_cacc_skip_3_1_f(transport, count_of_newacks))
160 * SFR-CACC algorithm:
161 * 3.2) Else if CYCLING_CHANGEOVER is 1, and t is less
162 * than next_tsn_at_change of the current primary, then
163 * the sender MUST NOT increment missing report count
166 static inline int sctp_cacc_skip_3_2(struct sctp_transport *primary, __u32 tsn)
168 if (primary->cacc.cycling_changeover &&
169 TSN_lt(tsn, primary->cacc.next_tsn_at_change))
175 * SFR-CACC algorithm:
176 * 3) If the missing report count for TSN t is to be
177 * incremented according to [RFC2960] and
178 * [SCTP_STEWART-2002], and CHANGEOVER_ACTIVE is set,
179 * then the sender MUST futher execute steps 3.1 and
180 * 3.2 to determine if the missing report count for
181 * TSN t SHOULD NOT be incremented.
183 * 3.3) If 3.1 and 3.2 do not dictate that the missing
184 * report count for t should not be incremented, then
185 * the sender SOULD increment missing report count for
186 * t (according to [RFC2960] and [SCTP_STEWART_2002]).
188 static inline int sctp_cacc_skip(struct sctp_transport *primary,
189 struct sctp_transport *transport,
190 int count_of_newacks,
193 if (primary->cacc.changeover_active &&
194 (sctp_cacc_skip_3_1(primary, transport, count_of_newacks)
195 || sctp_cacc_skip_3_2(primary, tsn)))
200 /* Initialize an existing sctp_outq. This does the boring stuff.
201 * You still need to define handlers if you really want to DO
202 * something with this structure...
204 void sctp_outq_init(struct sctp_association *asoc, struct sctp_outq *q)
207 INIT_LIST_HEAD(&q->out_chunk_list);
208 INIT_LIST_HEAD(&q->control_chunk_list);
209 INIT_LIST_HEAD(&q->retransmit);
210 INIT_LIST_HEAD(&q->sacked);
211 INIT_LIST_HEAD(&q->abandoned);
214 q->outstanding_bytes = 0;
222 /* Free the outqueue structure and any related pending chunks.
224 void sctp_outq_teardown(struct sctp_outq *q)
226 struct sctp_transport *transport;
227 struct list_head *lchunk, *temp;
228 struct sctp_chunk *chunk, *tmp;
230 /* Throw away unacknowledged chunks. */
231 list_for_each_entry(transport, &q->asoc->peer.transport_addr_list,
233 while ((lchunk = sctp_list_dequeue(&transport->transmitted)) != NULL) {
234 chunk = list_entry(lchunk, struct sctp_chunk,
236 /* Mark as part of a failed message. */
237 sctp_chunk_fail(chunk, q->error);
238 sctp_chunk_free(chunk);
242 /* Throw away chunks that have been gap ACKed. */
243 list_for_each_safe(lchunk, temp, &q->sacked) {
244 list_del_init(lchunk);
245 chunk = list_entry(lchunk, struct sctp_chunk,
247 sctp_chunk_fail(chunk, q->error);
248 sctp_chunk_free(chunk);
251 /* Throw away any chunks in the retransmit queue. */
252 list_for_each_safe(lchunk, temp, &q->retransmit) {
253 list_del_init(lchunk);
254 chunk = list_entry(lchunk, struct sctp_chunk,
256 sctp_chunk_fail(chunk, q->error);
257 sctp_chunk_free(chunk);
260 /* Throw away any chunks that are in the abandoned queue. */
261 list_for_each_safe(lchunk, temp, &q->abandoned) {
262 list_del_init(lchunk);
263 chunk = list_entry(lchunk, struct sctp_chunk,
265 sctp_chunk_fail(chunk, q->error);
266 sctp_chunk_free(chunk);
269 /* Throw away any leftover data chunks. */
270 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) {
272 /* Mark as send failure. */
273 sctp_chunk_fail(chunk, q->error);
274 sctp_chunk_free(chunk);
279 /* Throw away any leftover control chunks. */
280 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) {
281 list_del_init(&chunk->list);
282 sctp_chunk_free(chunk);
286 /* Free the outqueue structure and any related pending chunks. */
287 void sctp_outq_free(struct sctp_outq *q)
289 /* Throw away leftover chunks. */
290 sctp_outq_teardown(q);
292 /* If we were kmalloc()'d, free the memory. */
297 /* Put a new chunk in an sctp_outq. */
298 int sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk)
302 SCTP_DEBUG_PRINTK("sctp_outq_tail(%p, %p[%s])\n",
303 q, chunk, chunk && chunk->chunk_hdr ?
304 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type))
307 /* If it is data, queue it up, otherwise, send it
310 if (SCTP_CID_DATA == chunk->chunk_hdr->type) {
311 /* Is it OK to queue data chunks? */
312 /* From 9. Termination of Association
314 * When either endpoint performs a shutdown, the
315 * association on each peer will stop accepting new
316 * data from its user and only deliver data in queue
317 * at the time of sending or receiving the SHUTDOWN
320 switch (q->asoc->state) {
321 case SCTP_STATE_EMPTY:
322 case SCTP_STATE_CLOSED:
323 case SCTP_STATE_SHUTDOWN_PENDING:
324 case SCTP_STATE_SHUTDOWN_SENT:
325 case SCTP_STATE_SHUTDOWN_RECEIVED:
326 case SCTP_STATE_SHUTDOWN_ACK_SENT:
327 /* Cannot send after transport endpoint shutdown */
332 SCTP_DEBUG_PRINTK("outqueueing (%p, %p[%s])\n",
333 q, chunk, chunk && chunk->chunk_hdr ?
334 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type))
337 sctp_outq_tail_data(q, chunk);
338 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED)
339 SCTP_INC_STATS(SCTP_MIB_OUTUNORDERCHUNKS);
341 SCTP_INC_STATS(SCTP_MIB_OUTORDERCHUNKS);
346 list_add_tail(&chunk->list, &q->control_chunk_list);
347 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);
354 error = sctp_outq_flush(q, 0);
359 /* Insert a chunk into the sorted list based on the TSNs. The retransmit list
360 * and the abandoned list are in ascending order.
362 static void sctp_insert_list(struct list_head *head, struct list_head *new)
364 struct list_head *pos;
365 struct sctp_chunk *nchunk, *lchunk;
369 nchunk = list_entry(new, struct sctp_chunk, transmitted_list);
370 ntsn = ntohl(nchunk->subh.data_hdr->tsn);
372 list_for_each(pos, head) {
373 lchunk = list_entry(pos, struct sctp_chunk, transmitted_list);
374 ltsn = ntohl(lchunk->subh.data_hdr->tsn);
375 if (TSN_lt(ntsn, ltsn)) {
376 list_add(new, pos->prev);
382 list_add_tail(new, head);
385 /* Mark all the eligible packets on a transport for retransmission. */
386 void sctp_retransmit_mark(struct sctp_outq *q,
387 struct sctp_transport *transport,
390 struct list_head *lchunk, *ltemp;
391 struct sctp_chunk *chunk;
393 /* Walk through the specified transmitted queue. */
394 list_for_each_safe(lchunk, ltemp, &transport->transmitted) {
395 chunk = list_entry(lchunk, struct sctp_chunk,
398 /* If the chunk is abandoned, move it to abandoned list. */
399 if (sctp_chunk_abandoned(chunk)) {
400 list_del_init(lchunk);
401 sctp_insert_list(&q->abandoned, lchunk);
403 /* If this chunk has not been previousely acked,
404 * stop considering it 'outstanding'. Our peer
405 * will most likely never see it since it will
406 * not be retransmitted
408 if (!chunk->tsn_gap_acked) {
409 if (chunk->transport)
410 chunk->transport->flight_size -=
411 sctp_data_size(chunk);
412 q->outstanding_bytes -= sctp_data_size(chunk);
413 q->asoc->peer.rwnd += (sctp_data_size(chunk) +
414 sizeof(struct sk_buff));
419 /* If we are doing retransmission due to a timeout or pmtu
420 * discovery, only the chunks that are not yet acked should
421 * be added to the retransmit queue.
423 if ((reason == SCTP_RTXR_FAST_RTX &&
424 (chunk->fast_retransmit == SCTP_NEED_FRTX)) ||
425 (reason != SCTP_RTXR_FAST_RTX && !chunk->tsn_gap_acked)) {
426 /* If this chunk was sent less then 1 rto ago, do not
427 * retransmit this chunk, but give the peer time
428 * to acknowlege it. Do this only when
429 * retransmitting due to T3 timeout.
431 if (reason == SCTP_RTXR_T3_RTX &&
432 time_before(jiffies, chunk->sent_at +
433 transport->last_rto))
436 /* RFC 2960 6.2.1 Processing a Received SACK
438 * C) Any time a DATA chunk is marked for
439 * retransmission (via either T3-rtx timer expiration
440 * (Section 6.3.3) or via fast retransmit
441 * (Section 7.2.4)), add the data size of those
442 * chunks to the rwnd.
444 q->asoc->peer.rwnd += (sctp_data_size(chunk) +
445 sizeof(struct sk_buff));
446 q->outstanding_bytes -= sctp_data_size(chunk);
447 if (chunk->transport)
448 transport->flight_size -= sctp_data_size(chunk);
450 /* sctpimpguide-05 Section 2.8.2
451 * M5) If a T3-rtx timer expires, the
452 * 'TSN.Missing.Report' of all affected TSNs is set
455 chunk->tsn_missing_report = 0;
457 /* If a chunk that is being used for RTT measurement
458 * has to be retransmitted, we cannot use this chunk
459 * anymore for RTT measurements. Reset rto_pending so
460 * that a new RTT measurement is started when a new
461 * data chunk is sent.
463 if (chunk->rtt_in_progress) {
464 chunk->rtt_in_progress = 0;
465 transport->rto_pending = 0;
468 /* Move the chunk to the retransmit queue. The chunks
469 * on the retransmit queue are always kept in order.
471 list_del_init(lchunk);
472 sctp_insert_list(&q->retransmit, lchunk);
476 SCTP_DEBUG_PRINTK("%s: transport: %p, reason: %d, "
477 "cwnd: %d, ssthresh: %d, flight_size: %d, "
478 "pba: %d\n", __func__,
480 transport->cwnd, transport->ssthresh,
481 transport->flight_size,
482 transport->partial_bytes_acked);
486 /* Mark all the eligible packets on a transport for retransmission and force
489 void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
490 sctp_retransmit_reason_t reason)
495 case SCTP_RTXR_T3_RTX:
496 SCTP_INC_STATS(SCTP_MIB_T3_RETRANSMITS);
497 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_T3_RTX);
498 /* Update the retran path if the T3-rtx timer has expired for
499 * the current retran path.
501 if (transport == transport->asoc->peer.retran_path)
502 sctp_assoc_update_retran_path(transport->asoc);
503 transport->asoc->rtx_data_chunks +=
504 transport->asoc->unack_data;
506 case SCTP_RTXR_FAST_RTX:
507 SCTP_INC_STATS(SCTP_MIB_FAST_RETRANSMITS);
508 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_FAST_RTX);
511 case SCTP_RTXR_PMTUD:
512 SCTP_INC_STATS(SCTP_MIB_PMTUD_RETRANSMITS);
514 case SCTP_RTXR_T1_RTX:
515 SCTP_INC_STATS(SCTP_MIB_T1_RETRANSMITS);
516 transport->asoc->init_retries++;
522 sctp_retransmit_mark(q, transport, reason);
524 /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination,
525 * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by
526 * following the procedures outlined in C1 - C5.
528 if (reason == SCTP_RTXR_T3_RTX)
529 sctp_generate_fwdtsn(q, q->asoc->ctsn_ack_point);
531 /* Flush the queues only on timeout, since fast_rtx is only
532 * triggered during sack processing and the queue
533 * will be flushed at the end.
535 if (reason != SCTP_RTXR_FAST_RTX)
536 error = sctp_outq_flush(q, /* rtx_timeout */ 1);
539 q->asoc->base.sk->sk_err = -error;
543 * Transmit DATA chunks on the retransmit queue. Upon return from
544 * sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which
545 * need to be transmitted by the caller.
546 * We assume that pkt->transport has already been set.
548 * The return value is a normal kernel error return value.
550 static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
551 int rtx_timeout, int *start_timer)
553 struct list_head *lqueue;
554 struct sctp_transport *transport = pkt->transport;
556 struct sctp_chunk *chunk, *chunk1;
557 struct sctp_association *asoc;
564 lqueue = &q->retransmit;
565 fast_rtx = q->fast_rtx;
567 /* This loop handles time-out retransmissions, fast retransmissions,
568 * and retransmissions due to opening of whindow.
570 * RFC 2960 6.3.3 Handle T3-rtx Expiration
572 * E3) Determine how many of the earliest (i.e., lowest TSN)
573 * outstanding DATA chunks for the address for which the
574 * T3-rtx has expired will fit into a single packet, subject
575 * to the MTU constraint for the path corresponding to the
576 * destination transport address to which the retransmission
577 * is being sent (this may be different from the address for
578 * which the timer expires [see Section 6.4]). Call this value
579 * K. Bundle and retransmit those K DATA chunks in a single
580 * packet to the destination endpoint.
582 * [Just to be painfully clear, if we are retransmitting
583 * because a timeout just happened, we should send only ONE
584 * packet of retransmitted data.]
586 * For fast retransmissions we also send only ONE packet. However,
587 * if we are just flushing the queue due to open window, we'll
588 * try to send as much as possible.
590 list_for_each_entry_safe(chunk, chunk1, lqueue, transmitted_list) {
592 /* Make sure that Gap Acked TSNs are not retransmitted. A
593 * simple approach is just to move such TSNs out of the
594 * way and into a 'transmitted' queue and skip to the
597 if (chunk->tsn_gap_acked) {
598 list_del(&chunk->transmitted_list);
599 list_add_tail(&chunk->transmitted_list,
600 &transport->transmitted);
604 /* If we are doing fast retransmit, ignore non-fast_rtransmit
607 if (fast_rtx && !chunk->fast_retransmit)
610 /* Attempt to append this chunk to the packet. */
611 status = sctp_packet_append_chunk(pkt, chunk);
614 case SCTP_XMIT_PMTU_FULL:
615 /* Send this packet. */
616 error = sctp_packet_transmit(pkt);
618 /* If we are retransmitting, we should only
619 * send a single packet.
621 if (rtx_timeout || fast_rtx)
624 /* Bundle next chunk in the next round. */
627 case SCTP_XMIT_RWND_FULL:
628 /* Send this packet. */
629 error = sctp_packet_transmit(pkt);
631 /* Stop sending DATA as there is no more room
637 case SCTP_XMIT_NAGLE_DELAY:
638 /* Send this packet. */
639 error = sctp_packet_transmit(pkt);
641 /* Stop sending DATA because of nagle delay. */
646 /* The append was successful, so add this chunk to
647 * the transmitted list.
649 list_del(&chunk->transmitted_list);
650 list_add_tail(&chunk->transmitted_list,
651 &transport->transmitted);
653 /* Mark the chunk as ineligible for fast retransmit
654 * after it is retransmitted.
656 if (chunk->fast_retransmit == SCTP_NEED_FRTX)
657 chunk->fast_retransmit = SCTP_DONT_FRTX;
659 /* Force start T3-rtx timer when fast retransmitting
660 * the earliest outstanding TSN
662 if (!timer && fast_rtx &&
663 ntohl(chunk->subh.data_hdr->tsn) ==
664 asoc->ctsn_ack_point + 1)
671 /* Set the timer if there were no errors */
672 if (!error && !timer)
679 /* If we are here due to a retransmit timeout or a fast
680 * retransmit and if there are any chunks left in the retransmit
681 * queue that could not fit in the PMTU sized packet, they need
682 * to be marked as ineligible for a subsequent fast retransmit.
684 if (rtx_timeout || fast_rtx) {
685 list_for_each_entry(chunk1, lqueue, transmitted_list) {
686 if (chunk1->fast_retransmit == SCTP_NEED_FRTX)
687 chunk1->fast_retransmit = SCTP_DONT_FRTX;
691 *start_timer = timer;
693 /* Clear fast retransmit hint */
700 /* Cork the outqueue so queued chunks are really queued. */
701 int sctp_outq_uncork(struct sctp_outq *q)
706 error = sctp_outq_flush(q, 0);
712 * Try to flush an outqueue.
714 * Description: Send everything in q which we legally can, subject to
715 * congestion limitations.
716 * * Note: This function can be called from multiple contexts so appropriate
717 * locking concerns must be made. Today we use the sock lock to protect
720 static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout)
722 struct sctp_packet *packet;
723 struct sctp_packet singleton;
724 struct sctp_association *asoc = q->asoc;
725 __u16 sport = asoc->base.bind_addr.port;
726 __u16 dport = asoc->peer.port;
727 __u32 vtag = asoc->peer.i.init_tag;
728 struct sctp_transport *transport = NULL;
729 struct sctp_transport *new_transport;
730 struct sctp_chunk *chunk, *tmp;
736 /* These transports have chunks to send. */
737 struct list_head transport_list;
738 struct list_head *ltransport;
740 INIT_LIST_HEAD(&transport_list);
746 * When bundling control chunks with DATA chunks, an
747 * endpoint MUST place control chunks first in the outbound
748 * SCTP packet. The transmitter MUST transmit DATA chunks
749 * within a SCTP packet in increasing order of TSN.
753 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) {
754 list_del_init(&chunk->list);
756 /* Pick the right transport to use. */
757 new_transport = chunk->transport;
759 if (!new_transport) {
761 * If we have a prior transport pointer, see if
762 * the destination address of the chunk
763 * matches the destination address of the
764 * current transport. If not a match, then
765 * try to look up the transport with a given
766 * destination address. We do this because
767 * after processing ASCONFs, we may have new
768 * transports created.
771 sctp_cmp_addr_exact(&chunk->dest,
773 new_transport = transport;
775 new_transport = sctp_assoc_lookup_paddr(asoc,
778 /* if we still don't have a new transport, then
779 * use the current active path.
782 new_transport = asoc->peer.active_path;
783 } else if ((new_transport->state == SCTP_INACTIVE) ||
784 (new_transport->state == SCTP_UNCONFIRMED)) {
785 /* If the chunk is Heartbeat or Heartbeat Ack,
786 * send it to chunk->transport, even if it's
789 * 3.3.6 Heartbeat Acknowledgement:
791 * A HEARTBEAT ACK is always sent to the source IP
792 * address of the IP datagram containing the
793 * HEARTBEAT chunk to which this ack is responding.
796 * ASCONF_ACKs also must be sent to the source.
798 if (chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT &&
799 chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT_ACK &&
800 chunk->chunk_hdr->type != SCTP_CID_ASCONF_ACK)
801 new_transport = asoc->peer.active_path;
804 /* Are we switching transports?
805 * Take care of transport locks.
807 if (new_transport != transport) {
808 transport = new_transport;
809 if (list_empty(&transport->send_ready)) {
810 list_add_tail(&transport->send_ready,
813 packet = &transport->packet;
814 sctp_packet_config(packet, vtag,
815 asoc->peer.ecn_capable);
818 switch (chunk->chunk_hdr->type) {
822 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN
823 * COMPLETE with any other chunks. [Send them immediately.]
826 case SCTP_CID_INIT_ACK:
827 case SCTP_CID_SHUTDOWN_COMPLETE:
828 sctp_packet_init(&singleton, transport, sport, dport);
829 sctp_packet_config(&singleton, vtag, 0);
830 sctp_packet_append_chunk(&singleton, chunk);
831 error = sctp_packet_transmit(&singleton);
837 if (sctp_test_T_bit(chunk)) {
838 packet->vtag = asoc->c.my_vtag;
840 /* The following chunks are "response" chunks, i.e.
841 * they are generated in response to something we
842 * received. If we are sending these, then we can
843 * send only 1 packet containing these chunks.
845 case SCTP_CID_HEARTBEAT_ACK:
846 case SCTP_CID_SHUTDOWN_ACK:
847 case SCTP_CID_COOKIE_ACK:
848 case SCTP_CID_COOKIE_ECHO:
850 case SCTP_CID_ECN_CWR:
851 case SCTP_CID_ASCONF_ACK:
856 case SCTP_CID_HEARTBEAT:
857 case SCTP_CID_SHUTDOWN:
858 case SCTP_CID_ECN_ECNE:
859 case SCTP_CID_ASCONF:
860 case SCTP_CID_FWD_TSN:
861 status = sctp_packet_transmit_chunk(packet, chunk,
863 if (status != SCTP_XMIT_OK) {
864 /* put the chunk back */
865 list_add(&chunk->list, &q->control_chunk_list);
870 /* We built a chunk with an illegal type! */
875 /* Is it OK to send data chunks? */
876 switch (asoc->state) {
877 case SCTP_STATE_COOKIE_ECHOED:
878 /* Only allow bundling when this packet has a COOKIE-ECHO
881 if (!packet || !packet->has_cookie_echo)
885 case SCTP_STATE_ESTABLISHED:
886 case SCTP_STATE_SHUTDOWN_PENDING:
887 case SCTP_STATE_SHUTDOWN_RECEIVED:
889 * RFC 2960 6.1 Transmission of DATA Chunks
891 * C) When the time comes for the sender to transmit,
892 * before sending new DATA chunks, the sender MUST
893 * first transmit any outstanding DATA chunks which
894 * are marked for retransmission (limited by the
897 if (!list_empty(&q->retransmit)) {
898 if (transport == asoc->peer.retran_path)
901 /* Switch transports & prepare the packet. */
903 transport = asoc->peer.retran_path;
905 if (list_empty(&transport->send_ready)) {
906 list_add_tail(&transport->send_ready,
910 packet = &transport->packet;
911 sctp_packet_config(packet, vtag,
912 asoc->peer.ecn_capable);
914 error = sctp_outq_flush_rtx(q, packet,
915 rtx_timeout, &start_timer);
918 sctp_transport_reset_timers(transport,
921 /* This can happen on COOKIE-ECHO resend. Only
922 * one chunk can get bundled with a COOKIE-ECHO.
924 if (packet->has_cookie_echo)
927 /* Don't send new data if there is still data
928 * waiting to retransmit.
930 if (!list_empty(&q->retransmit))
934 /* Apply Max.Burst limitation to the current transport in
935 * case it will be used for new data. We are going to
936 * rest it before we return, but we want to apply the limit
937 * to the currently queued data.
940 sctp_transport_burst_limited(transport);
942 /* Finally, transmit new packets. */
943 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) {
944 /* RFC 2960 6.5 Every DATA chunk MUST carry a valid
947 if (chunk->sinfo.sinfo_stream >=
948 asoc->c.sinit_num_ostreams) {
950 /* Mark as failed send. */
951 sctp_chunk_fail(chunk, SCTP_ERROR_INV_STRM);
952 sctp_chunk_free(chunk);
956 /* Has this chunk expired? */
957 if (sctp_chunk_abandoned(chunk)) {
958 sctp_chunk_fail(chunk, 0);
959 sctp_chunk_free(chunk);
963 /* If there is a specified transport, use it.
964 * Otherwise, we want to use the active path.
966 new_transport = chunk->transport;
967 if (!new_transport ||
968 ((new_transport->state == SCTP_INACTIVE) ||
969 (new_transport->state == SCTP_UNCONFIRMED)))
970 new_transport = asoc->peer.active_path;
972 /* Change packets if necessary. */
973 if (new_transport != transport) {
974 transport = new_transport;
976 /* Schedule to have this transport's
979 if (list_empty(&transport->send_ready)) {
980 list_add_tail(&transport->send_ready,
984 packet = &transport->packet;
985 sctp_packet_config(packet, vtag,
986 asoc->peer.ecn_capable);
987 /* We've switched transports, so apply the
988 * Burst limit to the new transport.
990 sctp_transport_burst_limited(transport);
993 SCTP_DEBUG_PRINTK("sctp_outq_flush(%p, %p[%s]), ",
995 chunk && chunk->chunk_hdr ?
996 sctp_cname(SCTP_ST_CHUNK(
997 chunk->chunk_hdr->type))
1000 SCTP_DEBUG_PRINTK("TX TSN 0x%x skb->head "
1001 "%p skb->users %d.\n",
1002 ntohl(chunk->subh.data_hdr->tsn),
1003 chunk->skb ?chunk->skb->head : NULL,
1005 atomic_read(&chunk->skb->users) : -1);
1007 /* Add the chunk to the packet. */
1008 status = sctp_packet_transmit_chunk(packet, chunk, 0);
1011 case SCTP_XMIT_PMTU_FULL:
1012 case SCTP_XMIT_RWND_FULL:
1013 case SCTP_XMIT_NAGLE_DELAY:
1014 /* We could not append this chunk, so put
1015 * the chunk back on the output queue.
1017 SCTP_DEBUG_PRINTK("sctp_outq_flush: could "
1018 "not transmit TSN: 0x%x, status: %d\n",
1019 ntohl(chunk->subh.data_hdr->tsn),
1021 sctp_outq_head_data(q, chunk);
1022 goto sctp_flush_out;
1026 /* The sender is in the SHUTDOWN-PENDING state,
1027 * The sender MAY set the I-bit in the DATA
1030 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING)
1031 chunk->chunk_hdr->flags |= SCTP_DATA_SACK_IMM;
1039 /* BUG: We assume that the sctp_packet_transmit()
1040 * call below will succeed all the time and add the
1041 * chunk to the transmitted list and restart the
1043 * It is possible that the call can fail under OOM
1046 * Is this really a problem? Won't this behave
1049 list_add_tail(&chunk->transmitted_list,
1050 &transport->transmitted);
1052 sctp_transport_reset_timers(transport, 0);
1056 /* Only let one DATA chunk get bundled with a
1057 * COOKIE-ECHO chunk.
1059 if (packet->has_cookie_echo)
1060 goto sctp_flush_out;
1071 /* Before returning, examine all the transports touched in
1072 * this call. Right now, we bluntly force clear all the
1073 * transports. Things might change after we implement Nagle.
1074 * But such an examination is still required.
1078 while ((ltransport = sctp_list_dequeue(&transport_list)) != NULL ) {
1079 struct sctp_transport *t = list_entry(ltransport,
1080 struct sctp_transport,
1082 packet = &t->packet;
1083 if (!sctp_packet_empty(packet))
1084 error = sctp_packet_transmit(packet);
1086 /* Clear the burst limited state, if any */
1087 sctp_transport_burst_reset(t);
1093 /* Update unack_data based on the incoming SACK chunk */
1094 static void sctp_sack_update_unack_data(struct sctp_association *assoc,
1095 struct sctp_sackhdr *sack)
1097 sctp_sack_variable_t *frags;
1101 unack_data = assoc->next_tsn - assoc->ctsn_ack_point - 1;
1103 frags = sack->variable;
1104 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); i++) {
1105 unack_data -= ((ntohs(frags[i].gab.end) -
1106 ntohs(frags[i].gab.start) + 1));
1109 assoc->unack_data = unack_data;
1112 /* Return the highest new tsn that is acknowledged by the given SACK chunk. */
1113 static __u32 sctp_highest_new_tsn(struct sctp_sackhdr *sack,
1114 struct sctp_association *asoc)
1116 struct sctp_transport *transport;
1117 struct sctp_chunk *chunk;
1118 __u32 highest_new_tsn, tsn;
1119 struct list_head *transport_list = &asoc->peer.transport_addr_list;
1121 highest_new_tsn = ntohl(sack->cum_tsn_ack);
1123 list_for_each_entry(transport, transport_list, transports) {
1124 list_for_each_entry(chunk, &transport->transmitted,
1126 tsn = ntohl(chunk->subh.data_hdr->tsn);
1128 if (!chunk->tsn_gap_acked &&
1129 TSN_lt(highest_new_tsn, tsn) &&
1130 sctp_acked(sack, tsn))
1131 highest_new_tsn = tsn;
1135 return highest_new_tsn;
1138 /* This is where we REALLY process a SACK.
1140 * Process the SACK against the outqueue. Mostly, this just frees
1141 * things off the transmitted queue.
1143 int sctp_outq_sack(struct sctp_outq *q, struct sctp_sackhdr *sack)
1145 struct sctp_association *asoc = q->asoc;
1146 struct sctp_transport *transport;
1147 struct sctp_chunk *tchunk = NULL;
1148 struct list_head *lchunk, *transport_list, *temp;
1149 sctp_sack_variable_t *frags = sack->variable;
1150 __u32 sack_ctsn, ctsn, tsn;
1151 __u32 highest_tsn, highest_new_tsn;
1153 unsigned outstanding;
1154 struct sctp_transport *primary = asoc->peer.primary_path;
1155 int count_of_newacks = 0;
1158 /* Grab the association's destination address list. */
1159 transport_list = &asoc->peer.transport_addr_list;
1161 sack_ctsn = ntohl(sack->cum_tsn_ack);
1162 gap_ack_blocks = ntohs(sack->num_gap_ack_blocks);
1164 * SFR-CACC algorithm:
1165 * On receipt of a SACK the sender SHOULD execute the
1166 * following statements.
1168 * 1) If the cumulative ack in the SACK passes next tsn_at_change
1169 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be
1170 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for
1172 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE
1173 * is set the receiver of the SACK MUST take the following actions:
1175 * A) Initialize the cacc_saw_newack to 0 for all destination
1178 * Only bother if changeover_active is set. Otherwise, this is
1179 * totally suboptimal to do on every SACK.
1181 if (primary->cacc.changeover_active) {
1182 u8 clear_cycling = 0;
1184 if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) {
1185 primary->cacc.changeover_active = 0;
1189 if (clear_cycling || gap_ack_blocks) {
1190 list_for_each_entry(transport, transport_list,
1193 transport->cacc.cycling_changeover = 0;
1195 transport->cacc.cacc_saw_newack = 0;
1200 /* Get the highest TSN in the sack. */
1201 highest_tsn = sack_ctsn;
1203 highest_tsn += ntohs(frags[gap_ack_blocks - 1].gab.end);
1205 if (TSN_lt(asoc->highest_sacked, highest_tsn)) {
1206 highest_new_tsn = highest_tsn;
1207 asoc->highest_sacked = highest_tsn;
1209 highest_new_tsn = sctp_highest_new_tsn(sack, asoc);
1213 /* Run through the retransmit queue. Credit bytes received
1214 * and free those chunks that we can.
1216 sctp_check_transmitted(q, &q->retransmit, NULL, sack, highest_new_tsn);
1218 /* Run through the transmitted queue.
1219 * Credit bytes received and free those chunks which we can.
1221 * This is a MASSIVE candidate for optimization.
1223 list_for_each_entry(transport, transport_list, transports) {
1224 sctp_check_transmitted(q, &transport->transmitted,
1225 transport, sack, highest_new_tsn);
1227 * SFR-CACC algorithm:
1228 * C) Let count_of_newacks be the number of
1229 * destinations for which cacc_saw_newack is set.
1231 if (transport->cacc.cacc_saw_newack)
1232 count_of_newacks ++;
1235 if (gap_ack_blocks) {
1236 list_for_each_entry(transport, transport_list, transports)
1237 sctp_mark_missing(q, &transport->transmitted, transport,
1238 highest_new_tsn, count_of_newacks);
1241 /* Move the Cumulative TSN Ack Point if appropriate. */
1242 if (TSN_lt(asoc->ctsn_ack_point, sack_ctsn))
1243 asoc->ctsn_ack_point = sack_ctsn;
1245 /* Update unack_data field in the assoc. */
1246 sctp_sack_update_unack_data(asoc, sack);
1248 ctsn = asoc->ctsn_ack_point;
1250 /* Throw away stuff rotting on the sack queue. */
1251 list_for_each_safe(lchunk, temp, &q->sacked) {
1252 tchunk = list_entry(lchunk, struct sctp_chunk,
1254 tsn = ntohl(tchunk->subh.data_hdr->tsn);
1255 if (TSN_lte(tsn, ctsn)) {
1256 list_del_init(&tchunk->transmitted_list);
1257 sctp_chunk_free(tchunk);
1261 /* ii) Set rwnd equal to the newly received a_rwnd minus the
1262 * number of bytes still outstanding after processing the
1263 * Cumulative TSN Ack and the Gap Ack Blocks.
1266 sack_a_rwnd = ntohl(sack->a_rwnd);
1267 outstanding = q->outstanding_bytes;
1269 if (outstanding < sack_a_rwnd)
1270 sack_a_rwnd -= outstanding;
1274 asoc->peer.rwnd = sack_a_rwnd;
1276 sctp_generate_fwdtsn(q, sack_ctsn);
1278 SCTP_DEBUG_PRINTK("%s: sack Cumulative TSN Ack is 0x%x.\n",
1279 __func__, sack_ctsn);
1280 SCTP_DEBUG_PRINTK("%s: Cumulative TSN Ack of association, "
1281 "%p is 0x%x. Adv peer ack point: 0x%x\n",
1282 __func__, asoc, ctsn, asoc->adv_peer_ack_point);
1284 /* See if all chunks are acked.
1285 * Make sure the empty queue handler will get run later.
1287 q->empty = (list_empty(&q->out_chunk_list) &&
1288 list_empty(&q->retransmit));
1292 list_for_each_entry(transport, transport_list, transports) {
1293 q->empty = q->empty && list_empty(&transport->transmitted);
1298 SCTP_DEBUG_PRINTK("sack queue is empty.\n");
1303 /* Is the outqueue empty? */
1304 int sctp_outq_is_empty(const struct sctp_outq *q)
1309 /********************************************************************
1310 * 2nd Level Abstractions
1311 ********************************************************************/
1313 /* Go through a transport's transmitted list or the association's retransmit
1314 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked.
1315 * The retransmit list will not have an associated transport.
1317 * I added coherent debug information output. --xguo
1319 * Instead of printing 'sacked' or 'kept' for each TSN on the
1320 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5.
1321 * KEPT TSN6-TSN7, etc.
1323 static void sctp_check_transmitted(struct sctp_outq *q,
1324 struct list_head *transmitted_queue,
1325 struct sctp_transport *transport,
1326 struct sctp_sackhdr *sack,
1327 __u32 highest_new_tsn_in_sack)
1329 struct list_head *lchunk;
1330 struct sctp_chunk *tchunk;
1331 struct list_head tlist;
1335 __u8 restart_timer = 0;
1336 int bytes_acked = 0;
1337 int migrate_bytes = 0;
1339 /* These state variables are for coherent debug output. --xguo */
1342 __u32 dbg_ack_tsn = 0; /* An ACKed TSN range starts here... */
1343 __u32 dbg_last_ack_tsn = 0; /* ...and finishes here. */
1344 __u32 dbg_kept_tsn = 0; /* An un-ACKed range starts here... */
1345 __u32 dbg_last_kept_tsn = 0; /* ...and finishes here. */
1347 /* 0 : The last TSN was ACKed.
1348 * 1 : The last TSN was NOT ACKed (i.e. KEPT).
1349 * -1: We need to initialize.
1351 int dbg_prt_state = -1;
1352 #endif /* SCTP_DEBUG */
1354 sack_ctsn = ntohl(sack->cum_tsn_ack);
1356 INIT_LIST_HEAD(&tlist);
1358 /* The while loop will skip empty transmitted queues. */
1359 while (NULL != (lchunk = sctp_list_dequeue(transmitted_queue))) {
1360 tchunk = list_entry(lchunk, struct sctp_chunk,
1363 if (sctp_chunk_abandoned(tchunk)) {
1364 /* Move the chunk to abandoned list. */
1365 sctp_insert_list(&q->abandoned, lchunk);
1367 /* If this chunk has not been acked, stop
1368 * considering it as 'outstanding'.
1370 if (!tchunk->tsn_gap_acked) {
1371 if (tchunk->transport)
1372 tchunk->transport->flight_size -=
1373 sctp_data_size(tchunk);
1374 q->outstanding_bytes -= sctp_data_size(tchunk);
1379 tsn = ntohl(tchunk->subh.data_hdr->tsn);
1380 if (sctp_acked(sack, tsn)) {
1381 /* If this queue is the retransmit queue, the
1382 * retransmit timer has already reclaimed
1383 * the outstanding bytes for this chunk, so only
1384 * count bytes associated with a transport.
1387 /* If this chunk is being used for RTT
1388 * measurement, calculate the RTT and update
1389 * the RTO using this value.
1391 * 6.3.1 C5) Karn's algorithm: RTT measurements
1392 * MUST NOT be made using packets that were
1393 * retransmitted (and thus for which it is
1394 * ambiguous whether the reply was for the
1395 * first instance of the packet or a later
1398 if (!tchunk->tsn_gap_acked &&
1400 tchunk->rtt_in_progress) {
1401 tchunk->rtt_in_progress = 0;
1402 rtt = jiffies - tchunk->sent_at;
1403 sctp_transport_update_rto(transport,
1408 /* If the chunk hasn't been marked as ACKED,
1409 * mark it and account bytes_acked if the
1410 * chunk had a valid transport (it will not
1411 * have a transport if ASCONF had deleted it
1412 * while DATA was outstanding).
1414 if (!tchunk->tsn_gap_acked) {
1415 tchunk->tsn_gap_acked = 1;
1416 bytes_acked += sctp_data_size(tchunk);
1417 if (!tchunk->transport)
1418 migrate_bytes += sctp_data_size(tchunk);
1421 if (TSN_lte(tsn, sack_ctsn)) {
1422 /* RFC 2960 6.3.2 Retransmission Timer Rules
1424 * R3) Whenever a SACK is received
1425 * that acknowledges the DATA chunk
1426 * with the earliest outstanding TSN
1427 * for that address, restart T3-rtx
1428 * timer for that address with its
1433 if (!tchunk->tsn_gap_acked) {
1435 * SFR-CACC algorithm:
1436 * 2) If the SACK contains gap acks
1437 * and the flag CHANGEOVER_ACTIVE is
1438 * set the receiver of the SACK MUST
1439 * take the following action:
1441 * B) For each TSN t being acked that
1442 * has not been acked in any SACK so
1443 * far, set cacc_saw_newack to 1 for
1444 * the destination that the TSN was
1448 sack->num_gap_ack_blocks &&
1449 q->asoc->peer.primary_path->cacc.
1451 transport->cacc.cacc_saw_newack
1455 list_add_tail(&tchunk->transmitted_list,
1458 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2
1459 * M2) Each time a SACK arrives reporting
1460 * 'Stray DATA chunk(s)' record the highest TSN
1461 * reported as newly acknowledged, call this
1462 * value 'HighestTSNinSack'. A newly
1463 * acknowledged DATA chunk is one not
1464 * previously acknowledged in a SACK.
1466 * When the SCTP sender of data receives a SACK
1467 * chunk that acknowledges, for the first time,
1468 * the receipt of a DATA chunk, all the still
1469 * unacknowledged DATA chunks whose TSN is
1470 * older than that newly acknowledged DATA
1471 * chunk, are qualified as 'Stray DATA chunks'.
1473 list_add_tail(lchunk, &tlist);
1477 switch (dbg_prt_state) {
1478 case 0: /* last TSN was ACKed */
1479 if (dbg_last_ack_tsn + 1 == tsn) {
1480 /* This TSN belongs to the
1481 * current ACK range.
1486 if (dbg_last_ack_tsn != dbg_ack_tsn) {
1487 /* Display the end of the
1490 SCTP_DEBUG_PRINTK("-%08x",
1494 /* Start a new range. */
1495 SCTP_DEBUG_PRINTK(",%08x", tsn);
1499 case 1: /* The last TSN was NOT ACKed. */
1500 if (dbg_last_kept_tsn != dbg_kept_tsn) {
1501 /* Display the end of current range. */
1502 SCTP_DEBUG_PRINTK("-%08x",
1506 SCTP_DEBUG_PRINTK("\n");
1508 /* FALL THROUGH... */
1510 /* This is the first-ever TSN we examined. */
1511 /* Start a new range of ACK-ed TSNs. */
1512 SCTP_DEBUG_PRINTK("ACKed: %08x", tsn);
1517 dbg_last_ack_tsn = tsn;
1518 #endif /* SCTP_DEBUG */
1521 if (tchunk->tsn_gap_acked) {
1522 SCTP_DEBUG_PRINTK("%s: Receiver reneged on "
1526 tchunk->tsn_gap_acked = 0;
1528 if (tchunk->transport)
1529 bytes_acked -= sctp_data_size(tchunk);
1531 /* RFC 2960 6.3.2 Retransmission Timer Rules
1533 * R4) Whenever a SACK is received missing a
1534 * TSN that was previously acknowledged via a
1535 * Gap Ack Block, start T3-rtx for the
1536 * destination address to which the DATA
1537 * chunk was originally
1538 * transmitted if it is not already running.
1543 list_add_tail(lchunk, &tlist);
1546 /* See the above comments on ACK-ed TSNs. */
1547 switch (dbg_prt_state) {
1549 if (dbg_last_kept_tsn + 1 == tsn)
1552 if (dbg_last_kept_tsn != dbg_kept_tsn)
1553 SCTP_DEBUG_PRINTK("-%08x",
1556 SCTP_DEBUG_PRINTK(",%08x", tsn);
1561 if (dbg_last_ack_tsn != dbg_ack_tsn)
1562 SCTP_DEBUG_PRINTK("-%08x",
1564 SCTP_DEBUG_PRINTK("\n");
1566 /* FALL THROUGH... */
1568 SCTP_DEBUG_PRINTK("KEPT: %08x",tsn);
1573 dbg_last_kept_tsn = tsn;
1574 #endif /* SCTP_DEBUG */
1579 /* Finish off the last range, displaying its ending TSN. */
1580 switch (dbg_prt_state) {
1582 if (dbg_last_ack_tsn != dbg_ack_tsn) {
1583 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_ack_tsn);
1585 SCTP_DEBUG_PRINTK("\n");
1590 if (dbg_last_kept_tsn != dbg_kept_tsn) {
1591 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_kept_tsn);
1593 SCTP_DEBUG_PRINTK("\n");
1596 #endif /* SCTP_DEBUG */
1599 /* We may have counted DATA that was migrated
1600 * to this transport due to DEL-IP operation.
1601 * Subtract those bytes, since the were never
1602 * send on this transport and shouldn't be
1603 * credited to this transport.
1605 bytes_acked -= migrate_bytes;
1607 /* 8.2. When an outstanding TSN is acknowledged,
1608 * the endpoint shall clear the error counter of
1609 * the destination transport address to which the
1610 * DATA chunk was last sent.
1611 * The association's overall error counter is
1614 transport->error_count = 0;
1615 transport->asoc->overall_error_count = 0;
1617 /* Mark the destination transport address as
1618 * active if it is not so marked.
1620 if ((transport->state == SCTP_INACTIVE) ||
1621 (transport->state == SCTP_UNCONFIRMED)) {
1622 sctp_assoc_control_transport(
1626 SCTP_RECEIVED_SACK);
1629 sctp_transport_raise_cwnd(transport, sack_ctsn,
1632 transport->flight_size -= bytes_acked;
1633 if (transport->flight_size == 0)
1634 transport->partial_bytes_acked = 0;
1635 q->outstanding_bytes -= bytes_acked + migrate_bytes;
1637 /* RFC 2960 6.1, sctpimpguide-06 2.15.2
1638 * When a sender is doing zero window probing, it
1639 * should not timeout the association if it continues
1640 * to receive new packets from the receiver. The
1641 * reason is that the receiver MAY keep its window
1642 * closed for an indefinite time.
1643 * A sender is doing zero window probing when the
1644 * receiver's advertised window is zero, and there is
1645 * only one data chunk in flight to the receiver.
1647 if (!q->asoc->peer.rwnd &&
1648 !list_empty(&tlist) &&
1649 (sack_ctsn+2 == q->asoc->next_tsn)) {
1650 SCTP_DEBUG_PRINTK("%s: SACK received for zero "
1651 "window probe: %u\n",
1652 __func__, sack_ctsn);
1653 q->asoc->overall_error_count = 0;
1654 transport->error_count = 0;
1658 /* RFC 2960 6.3.2 Retransmission Timer Rules
1660 * R2) Whenever all outstanding data sent to an address have
1661 * been acknowledged, turn off the T3-rtx timer of that
1664 if (!transport->flight_size) {
1665 if (timer_pending(&transport->T3_rtx_timer) &&
1666 del_timer(&transport->T3_rtx_timer)) {
1667 sctp_transport_put(transport);
1669 } else if (restart_timer) {
1670 if (!mod_timer(&transport->T3_rtx_timer,
1671 jiffies + transport->rto))
1672 sctp_transport_hold(transport);
1676 list_splice(&tlist, transmitted_queue);
1679 /* Mark chunks as missing and consequently may get retransmitted. */
1680 static void sctp_mark_missing(struct sctp_outq *q,
1681 struct list_head *transmitted_queue,
1682 struct sctp_transport *transport,
1683 __u32 highest_new_tsn_in_sack,
1684 int count_of_newacks)
1686 struct sctp_chunk *chunk;
1688 char do_fast_retransmit = 0;
1689 struct sctp_transport *primary = q->asoc->peer.primary_path;
1691 list_for_each_entry(chunk, transmitted_queue, transmitted_list) {
1693 tsn = ntohl(chunk->subh.data_hdr->tsn);
1695 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all
1696 * 'Unacknowledged TSN's', if the TSN number of an
1697 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack'
1698 * value, increment the 'TSN.Missing.Report' count on that
1699 * chunk if it has NOT been fast retransmitted or marked for
1700 * fast retransmit already.
1702 if (chunk->fast_retransmit == SCTP_CAN_FRTX &&
1703 !chunk->tsn_gap_acked &&
1704 TSN_lt(tsn, highest_new_tsn_in_sack)) {
1706 /* SFR-CACC may require us to skip marking
1707 * this chunk as missing.
1709 if (!transport || !sctp_cacc_skip(primary, transport,
1710 count_of_newacks, tsn)) {
1711 chunk->tsn_missing_report++;
1714 "%s: TSN 0x%x missing counter: %d\n",
1716 chunk->tsn_missing_report);
1720 * M4) If any DATA chunk is found to have a
1721 * 'TSN.Missing.Report'
1722 * value larger than or equal to 3, mark that chunk for
1723 * retransmission and start the fast retransmit procedure.
1726 if (chunk->tsn_missing_report >= 3) {
1727 chunk->fast_retransmit = SCTP_NEED_FRTX;
1728 do_fast_retransmit = 1;
1733 if (do_fast_retransmit)
1734 sctp_retransmit(q, transport, SCTP_RTXR_FAST_RTX);
1736 SCTP_DEBUG_PRINTK("%s: transport: %p, cwnd: %d, "
1737 "ssthresh: %d, flight_size: %d, pba: %d\n",
1738 __func__, transport, transport->cwnd,
1739 transport->ssthresh, transport->flight_size,
1740 transport->partial_bytes_acked);
1744 /* Is the given TSN acked by this packet? */
1745 static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn)
1748 sctp_sack_variable_t *frags;
1750 __u32 ctsn = ntohl(sack->cum_tsn_ack);
1752 if (TSN_lte(tsn, ctsn))
1755 /* 3.3.4 Selective Acknowledgement (SACK) (3):
1758 * These fields contain the Gap Ack Blocks. They are repeated
1759 * for each Gap Ack Block up to the number of Gap Ack Blocks
1760 * defined in the Number of Gap Ack Blocks field. All DATA
1761 * chunks with TSNs greater than or equal to (Cumulative TSN
1762 * Ack + Gap Ack Block Start) and less than or equal to
1763 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack
1764 * Block are assumed to have been received correctly.
1767 frags = sack->variable;
1769 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); ++i) {
1770 if (TSN_lte(ntohs(frags[i].gab.start), gap) &&
1771 TSN_lte(gap, ntohs(frags[i].gab.end)))
1780 static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip *skiplist,
1781 int nskips, __be16 stream)
1785 for (i = 0; i < nskips; i++) {
1786 if (skiplist[i].stream == stream)
1792 /* Create and add a fwdtsn chunk to the outq's control queue if needed. */
1793 static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 ctsn)
1795 struct sctp_association *asoc = q->asoc;
1796 struct sctp_chunk *ftsn_chunk = NULL;
1797 struct sctp_fwdtsn_skip ftsn_skip_arr[10];
1801 struct sctp_chunk *chunk;
1802 struct list_head *lchunk, *temp;
1804 if (!asoc->peer.prsctp_capable)
1807 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the
1810 * If (Advanced.Peer.Ack.Point < SackCumAck), then update
1811 * Advanced.Peer.Ack.Point to be equal to SackCumAck.
1813 if (TSN_lt(asoc->adv_peer_ack_point, ctsn))
1814 asoc->adv_peer_ack_point = ctsn;
1816 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point"
1817 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as
1818 * the chunk next in the out-queue space is marked as "abandoned" as
1819 * shown in the following example:
1821 * Assuming that a SACK arrived with the Cumulative TSN ACK 102
1822 * and the Advanced.Peer.Ack.Point is updated to this value:
1824 * out-queue at the end of ==> out-queue after Adv.Ack.Point
1825 * normal SACK processing local advancement
1827 * Adv.Ack.Pt-> 102 acked 102 acked
1828 * 103 abandoned 103 abandoned
1829 * 104 abandoned Adv.Ack.P-> 104 abandoned
1831 * 106 acked 106 acked
1834 * In this example, the data sender successfully advanced the
1835 * "Advanced.Peer.Ack.Point" from 102 to 104 locally.
1837 list_for_each_safe(lchunk, temp, &q->abandoned) {
1838 chunk = list_entry(lchunk, struct sctp_chunk,
1840 tsn = ntohl(chunk->subh.data_hdr->tsn);
1842 /* Remove any chunks in the abandoned queue that are acked by
1845 if (TSN_lte(tsn, ctsn)) {
1846 list_del_init(lchunk);
1847 sctp_chunk_free(chunk);
1849 if (TSN_lte(tsn, asoc->adv_peer_ack_point+1)) {
1850 asoc->adv_peer_ack_point = tsn;
1851 if (chunk->chunk_hdr->flags &
1852 SCTP_DATA_UNORDERED)
1854 skip_pos = sctp_get_skip_pos(&ftsn_skip_arr[0],
1856 chunk->subh.data_hdr->stream);
1857 ftsn_skip_arr[skip_pos].stream =
1858 chunk->subh.data_hdr->stream;
1859 ftsn_skip_arr[skip_pos].ssn =
1860 chunk->subh.data_hdr->ssn;
1861 if (skip_pos == nskips)
1870 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point"
1871 * is greater than the Cumulative TSN ACK carried in the received
1872 * SACK, the data sender MUST send the data receiver a FORWARD TSN
1873 * chunk containing the latest value of the
1874 * "Advanced.Peer.Ack.Point".
1876 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD
1877 * list each stream and sequence number in the forwarded TSN. This
1878 * information will enable the receiver to easily find any
1879 * stranded TSN's waiting on stream reorder queues. Each stream
1880 * SHOULD only be reported once; this means that if multiple
1881 * abandoned messages occur in the same stream then only the
1882 * highest abandoned stream sequence number is reported. If the
1883 * total size of the FORWARD TSN does NOT fit in a single MTU then
1884 * the sender of the FORWARD TSN SHOULD lower the
1885 * Advanced.Peer.Ack.Point to the last TSN that will fit in a
1888 if (asoc->adv_peer_ack_point > ctsn)
1889 ftsn_chunk = sctp_make_fwdtsn(asoc, asoc->adv_peer_ack_point,
1890 nskips, &ftsn_skip_arr[0]);
1893 list_add_tail(&ftsn_chunk->list, &q->control_chunk_list);
1894 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS);