1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* SCTP kernel implementation
3 * (C) Copyright IBM Corp. 2001, 2004
4 * Copyright (c) 1999-2000 Cisco, Inc.
5 * Copyright (c) 1999-2001 Motorola, Inc.
6 * Copyright (c) 2001-2003 Intel Corp.
8 * This file is part of the SCTP kernel implementation
10 * These functions implement the sctp_outq class. The outqueue handles
11 * bundling and queueing of outgoing SCTP chunks.
13 * Please send any bug reports or fixes you make to the
15 * lksctp developers <linux-sctp@vger.kernel.org>
17 * Written or modified by:
18 * La Monte H.P. Yarroll <piggy@acm.org>
19 * Karl Knutson <karl@athena.chicago.il.us>
20 * Perry Melange <pmelange@null.cc.uic.edu>
21 * Xingang Guo <xingang.guo@intel.com>
22 * Hui Huang <hui.huang@nokia.com>
23 * Sridhar Samudrala <sri@us.ibm.com>
24 * Jon Grimm <jgrimm@us.ibm.com>
27 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
29 #include <linux/types.h>
30 #include <linux/list.h> /* For struct list_head */
31 #include <linux/socket.h>
33 #include <linux/slab.h>
34 #include <net/sock.h> /* For skb_set_owner_w */
36 #include <net/sctp/sctp.h>
37 #include <net/sctp/sm.h>
38 #include <net/sctp/stream_sched.h>
40 /* Declare internal functions here. */
41 static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn);
42 static void sctp_check_transmitted(struct sctp_outq *q,
43 struct list_head *transmitted_queue,
44 struct sctp_transport *transport,
45 union sctp_addr *saddr,
46 struct sctp_sackhdr *sack,
47 __u32 *highest_new_tsn);
49 static void sctp_mark_missing(struct sctp_outq *q,
50 struct list_head *transmitted_queue,
51 struct sctp_transport *transport,
52 __u32 highest_new_tsn,
53 int count_of_newacks);
55 static void sctp_outq_flush(struct sctp_outq *q, int rtx_timeout, gfp_t gfp);
57 /* Add data to the front of the queue. */
58 static inline void sctp_outq_head_data(struct sctp_outq *q,
59 struct sctp_chunk *ch)
61 struct sctp_stream_out_ext *oute;
64 list_add(&ch->list, &q->out_chunk_list);
65 q->out_qlen += ch->skb->len;
67 stream = sctp_chunk_stream_no(ch);
68 oute = SCTP_SO(&q->asoc->stream, stream)->ext;
69 list_add(&ch->stream_list, &oute->outq);
72 /* Take data from the front of the queue. */
73 static inline struct sctp_chunk *sctp_outq_dequeue_data(struct sctp_outq *q)
75 return q->sched->dequeue(q);
78 /* Add data chunk to the end of the queue. */
79 static inline void sctp_outq_tail_data(struct sctp_outq *q,
80 struct sctp_chunk *ch)
82 struct sctp_stream_out_ext *oute;
85 list_add_tail(&ch->list, &q->out_chunk_list);
86 q->out_qlen += ch->skb->len;
88 stream = sctp_chunk_stream_no(ch);
89 oute = SCTP_SO(&q->asoc->stream, stream)->ext;
90 list_add_tail(&ch->stream_list, &oute->outq);
95 * D) If count_of_newacks is greater than or equal to 2
96 * and t was not sent to the current primary then the
97 * sender MUST NOT increment missing report count for t.
99 static inline int sctp_cacc_skip_3_1_d(struct sctp_transport *primary,
100 struct sctp_transport *transport,
101 int count_of_newacks)
103 if (count_of_newacks >= 2 && transport != primary)
109 * SFR-CACC algorithm:
110 * F) If count_of_newacks is less than 2, let d be the
111 * destination to which t was sent. If cacc_saw_newack
112 * is 0 for destination d, then the sender MUST NOT
113 * increment missing report count for t.
115 static inline int sctp_cacc_skip_3_1_f(struct sctp_transport *transport,
116 int count_of_newacks)
118 if (count_of_newacks < 2 &&
119 (transport && !transport->cacc.cacc_saw_newack))
125 * SFR-CACC algorithm:
126 * 3.1) If CYCLING_CHANGEOVER is 0, the sender SHOULD
127 * execute steps C, D, F.
129 * C has been implemented in sctp_outq_sack
131 static inline int sctp_cacc_skip_3_1(struct sctp_transport *primary,
132 struct sctp_transport *transport,
133 int count_of_newacks)
135 if (!primary->cacc.cycling_changeover) {
136 if (sctp_cacc_skip_3_1_d(primary, transport, count_of_newacks))
138 if (sctp_cacc_skip_3_1_f(transport, count_of_newacks))
146 * SFR-CACC algorithm:
147 * 3.2) Else if CYCLING_CHANGEOVER is 1, and t is less
148 * than next_tsn_at_change of the current primary, then
149 * the sender MUST NOT increment missing report count
152 static inline int sctp_cacc_skip_3_2(struct sctp_transport *primary, __u32 tsn)
154 if (primary->cacc.cycling_changeover &&
155 TSN_lt(tsn, primary->cacc.next_tsn_at_change))
161 * SFR-CACC algorithm:
162 * 3) If the missing report count for TSN t is to be
163 * incremented according to [RFC2960] and
164 * [SCTP_STEWART-2002], and CHANGEOVER_ACTIVE is set,
165 * then the sender MUST further execute steps 3.1 and
166 * 3.2 to determine if the missing report count for
167 * TSN t SHOULD NOT be incremented.
169 * 3.3) If 3.1 and 3.2 do not dictate that the missing
170 * report count for t should not be incremented, then
171 * the sender SHOULD increment missing report count for
172 * t (according to [RFC2960] and [SCTP_STEWART_2002]).
174 static inline int sctp_cacc_skip(struct sctp_transport *primary,
175 struct sctp_transport *transport,
176 int count_of_newacks,
179 if (primary->cacc.changeover_active &&
180 (sctp_cacc_skip_3_1(primary, transport, count_of_newacks) ||
181 sctp_cacc_skip_3_2(primary, tsn)))
186 /* Initialize an existing sctp_outq. This does the boring stuff.
187 * You still need to define handlers if you really want to DO
188 * something with this structure...
190 void sctp_outq_init(struct sctp_association *asoc, struct sctp_outq *q)
192 memset(q, 0, sizeof(struct sctp_outq));
195 INIT_LIST_HEAD(&q->out_chunk_list);
196 INIT_LIST_HEAD(&q->control_chunk_list);
197 INIT_LIST_HEAD(&q->retransmit);
198 INIT_LIST_HEAD(&q->sacked);
199 INIT_LIST_HEAD(&q->abandoned);
200 sctp_sched_set_sched(asoc, sctp_sk(asoc->base.sk)->default_ss);
203 /* Free the outqueue structure and any related pending chunks.
205 static void __sctp_outq_teardown(struct sctp_outq *q)
207 struct sctp_transport *transport;
208 struct list_head *lchunk, *temp;
209 struct sctp_chunk *chunk, *tmp;
211 /* Throw away unacknowledged chunks. */
212 list_for_each_entry(transport, &q->asoc->peer.transport_addr_list,
214 while ((lchunk = sctp_list_dequeue(&transport->transmitted)) != NULL) {
215 chunk = list_entry(lchunk, struct sctp_chunk,
217 /* Mark as part of a failed message. */
218 sctp_chunk_fail(chunk, q->error);
219 sctp_chunk_free(chunk);
223 /* Throw away chunks that have been gap ACKed. */
224 list_for_each_safe(lchunk, temp, &q->sacked) {
225 list_del_init(lchunk);
226 chunk = list_entry(lchunk, struct sctp_chunk,
228 sctp_chunk_fail(chunk, q->error);
229 sctp_chunk_free(chunk);
232 /* Throw away any chunks in the retransmit queue. */
233 list_for_each_safe(lchunk, temp, &q->retransmit) {
234 list_del_init(lchunk);
235 chunk = list_entry(lchunk, struct sctp_chunk,
237 sctp_chunk_fail(chunk, q->error);
238 sctp_chunk_free(chunk);
241 /* Throw away any chunks that are in the abandoned queue. */
242 list_for_each_safe(lchunk, temp, &q->abandoned) {
243 list_del_init(lchunk);
244 chunk = list_entry(lchunk, struct sctp_chunk,
246 sctp_chunk_fail(chunk, q->error);
247 sctp_chunk_free(chunk);
250 /* Throw away any leftover data chunks. */
251 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) {
252 sctp_sched_dequeue_done(q, chunk);
254 /* Mark as send failure. */
255 sctp_chunk_fail(chunk, q->error);
256 sctp_chunk_free(chunk);
259 /* Throw away any leftover control chunks. */
260 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) {
261 list_del_init(&chunk->list);
262 sctp_chunk_free(chunk);
266 void sctp_outq_teardown(struct sctp_outq *q)
268 __sctp_outq_teardown(q);
269 sctp_outq_init(q->asoc, q);
272 /* Free the outqueue structure and any related pending chunks. */
273 void sctp_outq_free(struct sctp_outq *q)
275 /* Throw away leftover chunks. */
276 __sctp_outq_teardown(q);
279 /* Put a new chunk in an sctp_outq. */
280 void sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk, gfp_t gfp)
282 struct net *net = sock_net(q->asoc->base.sk);
284 pr_debug("%s: outq:%p, chunk:%p[%s]\n", __func__, q, chunk,
285 chunk && chunk->chunk_hdr ?
286 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) :
289 /* If it is data, queue it up, otherwise, send it
292 if (sctp_chunk_is_data(chunk)) {
293 pr_debug("%s: outqueueing: outq:%p, chunk:%p[%s])\n",
294 __func__, q, chunk, chunk && chunk->chunk_hdr ?
295 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) :
298 sctp_outq_tail_data(q, chunk);
299 if (chunk->asoc->peer.prsctp_capable &&
300 SCTP_PR_PRIO_ENABLED(chunk->sinfo.sinfo_flags))
301 chunk->asoc->sent_cnt_removable++;
302 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED)
303 SCTP_INC_STATS(net, SCTP_MIB_OUTUNORDERCHUNKS);
305 SCTP_INC_STATS(net, SCTP_MIB_OUTORDERCHUNKS);
307 list_add_tail(&chunk->list, &q->control_chunk_list);
308 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS);
312 sctp_outq_flush(q, 0, gfp);
315 /* Insert a chunk into the sorted list based on the TSNs. The retransmit list
316 * and the abandoned list are in ascending order.
318 static void sctp_insert_list(struct list_head *head, struct list_head *new)
320 struct list_head *pos;
321 struct sctp_chunk *nchunk, *lchunk;
325 nchunk = list_entry(new, struct sctp_chunk, transmitted_list);
326 ntsn = ntohl(nchunk->subh.data_hdr->tsn);
328 list_for_each(pos, head) {
329 lchunk = list_entry(pos, struct sctp_chunk, transmitted_list);
330 ltsn = ntohl(lchunk->subh.data_hdr->tsn);
331 if (TSN_lt(ntsn, ltsn)) {
332 list_add(new, pos->prev);
338 list_add_tail(new, head);
341 static int sctp_prsctp_prune_sent(struct sctp_association *asoc,
342 struct sctp_sndrcvinfo *sinfo,
343 struct list_head *queue, int msg_len)
345 struct sctp_chunk *chk, *temp;
347 list_for_each_entry_safe(chk, temp, queue, transmitted_list) {
348 struct sctp_stream_out *streamout;
350 if (!chk->msg->abandoned &&
351 (!SCTP_PR_PRIO_ENABLED(chk->sinfo.sinfo_flags) ||
352 chk->sinfo.sinfo_timetolive <= sinfo->sinfo_timetolive))
355 chk->msg->abandoned = 1;
356 list_del_init(&chk->transmitted_list);
357 sctp_insert_list(&asoc->outqueue.abandoned,
358 &chk->transmitted_list);
360 streamout = SCTP_SO(&asoc->stream, chk->sinfo.sinfo_stream);
361 asoc->sent_cnt_removable--;
362 asoc->abandoned_sent[SCTP_PR_INDEX(PRIO)]++;
363 streamout->ext->abandoned_sent[SCTP_PR_INDEX(PRIO)]++;
365 if (queue != &asoc->outqueue.retransmit &&
366 !chk->tsn_gap_acked) {
368 chk->transport->flight_size -=
370 asoc->outqueue.outstanding_bytes -= sctp_data_size(chk);
373 msg_len -= chk->skb->truesize + sizeof(struct sctp_chunk);
381 static int sctp_prsctp_prune_unsent(struct sctp_association *asoc,
382 struct sctp_sndrcvinfo *sinfo, int msg_len)
384 struct sctp_outq *q = &asoc->outqueue;
385 struct sctp_chunk *chk, *temp;
387 q->sched->unsched_all(&asoc->stream);
389 list_for_each_entry_safe(chk, temp, &q->out_chunk_list, list) {
390 if (!chk->msg->abandoned &&
391 (!(chk->chunk_hdr->flags & SCTP_DATA_FIRST_FRAG) ||
392 !SCTP_PR_PRIO_ENABLED(chk->sinfo.sinfo_flags) ||
393 chk->sinfo.sinfo_timetolive <= sinfo->sinfo_timetolive))
396 chk->msg->abandoned = 1;
397 sctp_sched_dequeue_common(q, chk);
398 asoc->sent_cnt_removable--;
399 asoc->abandoned_unsent[SCTP_PR_INDEX(PRIO)]++;
400 if (chk->sinfo.sinfo_stream < asoc->stream.outcnt) {
401 struct sctp_stream_out *streamout =
402 SCTP_SO(&asoc->stream, chk->sinfo.sinfo_stream);
404 streamout->ext->abandoned_unsent[SCTP_PR_INDEX(PRIO)]++;
407 msg_len -= chk->skb->truesize + sizeof(struct sctp_chunk);
408 sctp_chunk_free(chk);
413 q->sched->sched_all(&asoc->stream);
418 /* Abandon the chunks according their priorities */
419 void sctp_prsctp_prune(struct sctp_association *asoc,
420 struct sctp_sndrcvinfo *sinfo, int msg_len)
422 struct sctp_transport *transport;
424 if (!asoc->peer.prsctp_capable || !asoc->sent_cnt_removable)
427 msg_len = sctp_prsctp_prune_sent(asoc, sinfo,
428 &asoc->outqueue.retransmit,
433 list_for_each_entry(transport, &asoc->peer.transport_addr_list,
435 msg_len = sctp_prsctp_prune_sent(asoc, sinfo,
436 &transport->transmitted,
442 sctp_prsctp_prune_unsent(asoc, sinfo, msg_len);
445 /* Mark all the eligible packets on a transport for retransmission. */
446 void sctp_retransmit_mark(struct sctp_outq *q,
447 struct sctp_transport *transport,
450 struct list_head *lchunk, *ltemp;
451 struct sctp_chunk *chunk;
453 /* Walk through the specified transmitted queue. */
454 list_for_each_safe(lchunk, ltemp, &transport->transmitted) {
455 chunk = list_entry(lchunk, struct sctp_chunk,
458 /* If the chunk is abandoned, move it to abandoned list. */
459 if (sctp_chunk_abandoned(chunk)) {
460 list_del_init(lchunk);
461 sctp_insert_list(&q->abandoned, lchunk);
463 /* If this chunk has not been previousely acked,
464 * stop considering it 'outstanding'. Our peer
465 * will most likely never see it since it will
466 * not be retransmitted
468 if (!chunk->tsn_gap_acked) {
469 if (chunk->transport)
470 chunk->transport->flight_size -=
471 sctp_data_size(chunk);
472 q->outstanding_bytes -= sctp_data_size(chunk);
473 q->asoc->peer.rwnd += sctp_data_size(chunk);
478 /* If we are doing retransmission due to a timeout or pmtu
479 * discovery, only the chunks that are not yet acked should
480 * be added to the retransmit queue.
482 if ((reason == SCTP_RTXR_FAST_RTX &&
483 (chunk->fast_retransmit == SCTP_NEED_FRTX)) ||
484 (reason != SCTP_RTXR_FAST_RTX && !chunk->tsn_gap_acked)) {
485 /* RFC 2960 6.2.1 Processing a Received SACK
487 * C) Any time a DATA chunk is marked for
488 * retransmission (via either T3-rtx timer expiration
489 * (Section 6.3.3) or via fast retransmit
490 * (Section 7.2.4)), add the data size of those
491 * chunks to the rwnd.
493 q->asoc->peer.rwnd += sctp_data_size(chunk);
494 q->outstanding_bytes -= sctp_data_size(chunk);
495 if (chunk->transport)
496 transport->flight_size -= sctp_data_size(chunk);
498 /* sctpimpguide-05 Section 2.8.2
499 * M5) If a T3-rtx timer expires, the
500 * 'TSN.Missing.Report' of all affected TSNs is set
503 chunk->tsn_missing_report = 0;
505 /* If a chunk that is being used for RTT measurement
506 * has to be retransmitted, we cannot use this chunk
507 * anymore for RTT measurements. Reset rto_pending so
508 * that a new RTT measurement is started when a new
509 * data chunk is sent.
511 if (chunk->rtt_in_progress) {
512 chunk->rtt_in_progress = 0;
513 transport->rto_pending = 0;
516 /* Move the chunk to the retransmit queue. The chunks
517 * on the retransmit queue are always kept in order.
519 list_del_init(lchunk);
520 sctp_insert_list(&q->retransmit, lchunk);
524 pr_debug("%s: transport:%p, reason:%d, cwnd:%d, ssthresh:%d, "
525 "flight_size:%d, pba:%d\n", __func__, transport, reason,
526 transport->cwnd, transport->ssthresh, transport->flight_size,
527 transport->partial_bytes_acked);
530 /* Mark all the eligible packets on a transport for retransmission and force
533 void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
534 enum sctp_retransmit_reason reason)
536 struct net *net = sock_net(q->asoc->base.sk);
539 case SCTP_RTXR_T3_RTX:
540 SCTP_INC_STATS(net, SCTP_MIB_T3_RETRANSMITS);
541 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_T3_RTX);
542 /* Update the retran path if the T3-rtx timer has expired for
543 * the current retran path.
545 if (transport == transport->asoc->peer.retran_path)
546 sctp_assoc_update_retran_path(transport->asoc);
547 transport->asoc->rtx_data_chunks +=
548 transport->asoc->unack_data;
550 case SCTP_RTXR_FAST_RTX:
551 SCTP_INC_STATS(net, SCTP_MIB_FAST_RETRANSMITS);
552 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_FAST_RTX);
555 case SCTP_RTXR_PMTUD:
556 SCTP_INC_STATS(net, SCTP_MIB_PMTUD_RETRANSMITS);
558 case SCTP_RTXR_T1_RTX:
559 SCTP_INC_STATS(net, SCTP_MIB_T1_RETRANSMITS);
560 transport->asoc->init_retries++;
566 sctp_retransmit_mark(q, transport, reason);
568 /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination,
569 * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by
570 * following the procedures outlined in C1 - C5.
572 if (reason == SCTP_RTXR_T3_RTX)
573 q->asoc->stream.si->generate_ftsn(q, q->asoc->ctsn_ack_point);
575 /* Flush the queues only on timeout, since fast_rtx is only
576 * triggered during sack processing and the queue
577 * will be flushed at the end.
579 if (reason != SCTP_RTXR_FAST_RTX)
580 sctp_outq_flush(q, /* rtx_timeout */ 1, GFP_ATOMIC);
584 * Transmit DATA chunks on the retransmit queue. Upon return from
585 * __sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which
586 * need to be transmitted by the caller.
587 * We assume that pkt->transport has already been set.
589 * The return value is a normal kernel error return value.
591 static int __sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
592 int rtx_timeout, int *start_timer, gfp_t gfp)
594 struct sctp_transport *transport = pkt->transport;
595 struct sctp_chunk *chunk, *chunk1;
596 struct list_head *lqueue;
597 enum sctp_xmit status;
603 lqueue = &q->retransmit;
604 fast_rtx = q->fast_rtx;
606 /* This loop handles time-out retransmissions, fast retransmissions,
607 * and retransmissions due to opening of whindow.
609 * RFC 2960 6.3.3 Handle T3-rtx Expiration
611 * E3) Determine how many of the earliest (i.e., lowest TSN)
612 * outstanding DATA chunks for the address for which the
613 * T3-rtx has expired will fit into a single packet, subject
614 * to the MTU constraint for the path corresponding to the
615 * destination transport address to which the retransmission
616 * is being sent (this may be different from the address for
617 * which the timer expires [see Section 6.4]). Call this value
618 * K. Bundle and retransmit those K DATA chunks in a single
619 * packet to the destination endpoint.
621 * [Just to be painfully clear, if we are retransmitting
622 * because a timeout just happened, we should send only ONE
623 * packet of retransmitted data.]
625 * For fast retransmissions we also send only ONE packet. However,
626 * if we are just flushing the queue due to open window, we'll
627 * try to send as much as possible.
629 list_for_each_entry_safe(chunk, chunk1, lqueue, transmitted_list) {
630 /* If the chunk is abandoned, move it to abandoned list. */
631 if (sctp_chunk_abandoned(chunk)) {
632 list_del_init(&chunk->transmitted_list);
633 sctp_insert_list(&q->abandoned,
634 &chunk->transmitted_list);
638 /* Make sure that Gap Acked TSNs are not retransmitted. A
639 * simple approach is just to move such TSNs out of the
640 * way and into a 'transmitted' queue and skip to the
643 if (chunk->tsn_gap_acked) {
644 list_move_tail(&chunk->transmitted_list,
645 &transport->transmitted);
649 /* If we are doing fast retransmit, ignore non-fast_rtransmit
652 if (fast_rtx && !chunk->fast_retransmit)
656 /* Attempt to append this chunk to the packet. */
657 status = sctp_packet_append_chunk(pkt, chunk);
660 case SCTP_XMIT_PMTU_FULL:
661 if (!pkt->has_data && !pkt->has_cookie_echo) {
662 /* If this packet did not contain DATA then
663 * retransmission did not happen, so do it
664 * again. We'll ignore the error here since
665 * control chunks are already freed so there
666 * is nothing we can do.
668 sctp_packet_transmit(pkt, gfp);
672 /* Send this packet. */
673 error = sctp_packet_transmit(pkt, gfp);
675 /* If we are retransmitting, we should only
676 * send a single packet.
677 * Otherwise, try appending this chunk again.
679 if (rtx_timeout || fast_rtx)
684 /* Bundle next chunk in the next round. */
687 case SCTP_XMIT_RWND_FULL:
688 /* Send this packet. */
689 error = sctp_packet_transmit(pkt, gfp);
691 /* Stop sending DATA as there is no more room
697 case SCTP_XMIT_DELAY:
698 /* Send this packet. */
699 error = sctp_packet_transmit(pkt, gfp);
701 /* Stop sending DATA because of nagle delay. */
706 /* The append was successful, so add this chunk to
707 * the transmitted list.
709 list_move_tail(&chunk->transmitted_list,
710 &transport->transmitted);
712 /* Mark the chunk as ineligible for fast retransmit
713 * after it is retransmitted.
715 if (chunk->fast_retransmit == SCTP_NEED_FRTX)
716 chunk->fast_retransmit = SCTP_DONT_FRTX;
718 q->asoc->stats.rtxchunks++;
722 /* Set the timer if there were no errors */
723 if (!error && !timer)
730 /* If we are here due to a retransmit timeout or a fast
731 * retransmit and if there are any chunks left in the retransmit
732 * queue that could not fit in the PMTU sized packet, they need
733 * to be marked as ineligible for a subsequent fast retransmit.
735 if (rtx_timeout || fast_rtx) {
736 list_for_each_entry(chunk1, lqueue, transmitted_list) {
737 if (chunk1->fast_retransmit == SCTP_NEED_FRTX)
738 chunk1->fast_retransmit = SCTP_DONT_FRTX;
742 *start_timer = timer;
744 /* Clear fast retransmit hint */
751 /* Cork the outqueue so queued chunks are really queued. */
752 void sctp_outq_uncork(struct sctp_outq *q, gfp_t gfp)
757 sctp_outq_flush(q, 0, gfp);
760 static int sctp_packet_singleton(struct sctp_transport *transport,
761 struct sctp_chunk *chunk, gfp_t gfp)
763 const struct sctp_association *asoc = transport->asoc;
764 const __u16 sport = asoc->base.bind_addr.port;
765 const __u16 dport = asoc->peer.port;
766 const __u32 vtag = asoc->peer.i.init_tag;
767 struct sctp_packet singleton;
769 sctp_packet_init(&singleton, transport, sport, dport);
770 sctp_packet_config(&singleton, vtag, 0);
771 sctp_packet_append_chunk(&singleton, chunk);
772 return sctp_packet_transmit(&singleton, gfp);
775 /* Struct to hold the context during sctp outq flush */
776 struct sctp_flush_ctx {
778 /* Current transport being used. It's NOT the same as curr active one */
779 struct sctp_transport *transport;
780 /* These transports have chunks to send. */
781 struct list_head transport_list;
782 struct sctp_association *asoc;
783 /* Packet on the current transport above */
784 struct sctp_packet *packet;
788 /* transport: current transport */
789 static void sctp_outq_select_transport(struct sctp_flush_ctx *ctx,
790 struct sctp_chunk *chunk)
792 struct sctp_transport *new_transport = chunk->transport;
794 if (!new_transport) {
795 if (!sctp_chunk_is_data(chunk)) {
796 /* If we have a prior transport pointer, see if
797 * the destination address of the chunk
798 * matches the destination address of the
799 * current transport. If not a match, then
800 * try to look up the transport with a given
801 * destination address. We do this because
802 * after processing ASCONFs, we may have new
803 * transports created.
805 if (ctx->transport && sctp_cmp_addr_exact(&chunk->dest,
806 &ctx->transport->ipaddr))
807 new_transport = ctx->transport;
809 new_transport = sctp_assoc_lookup_paddr(ctx->asoc,
813 /* if we still don't have a new transport, then
814 * use the current active path.
817 new_transport = ctx->asoc->peer.active_path;
821 switch (new_transport->state) {
823 case SCTP_UNCONFIRMED:
825 /* If the chunk is Heartbeat or Heartbeat Ack,
826 * send it to chunk->transport, even if it's
829 * 3.3.6 Heartbeat Acknowledgement:
831 * A HEARTBEAT ACK is always sent to the source IP
832 * address of the IP datagram containing the
833 * HEARTBEAT chunk to which this ack is responding.
836 * ASCONF_ACKs also must be sent to the source.
838 type = chunk->chunk_hdr->type;
839 if (type != SCTP_CID_HEARTBEAT &&
840 type != SCTP_CID_HEARTBEAT_ACK &&
841 type != SCTP_CID_ASCONF_ACK)
842 new_transport = ctx->asoc->peer.active_path;
849 /* Are we switching transports? Take care of transport locks. */
850 if (new_transport != ctx->transport) {
851 ctx->transport = new_transport;
852 ctx->packet = &ctx->transport->packet;
854 if (list_empty(&ctx->transport->send_ready))
855 list_add_tail(&ctx->transport->send_ready,
856 &ctx->transport_list);
858 sctp_packet_config(ctx->packet,
859 ctx->asoc->peer.i.init_tag,
860 ctx->asoc->peer.ecn_capable);
861 /* We've switched transports, so apply the
862 * Burst limit to the new transport.
864 sctp_transport_burst_limited(ctx->transport);
868 static void sctp_outq_flush_ctrl(struct sctp_flush_ctx *ctx)
870 struct sctp_chunk *chunk, *tmp;
871 enum sctp_xmit status;
872 int one_packet, error;
874 list_for_each_entry_safe(chunk, tmp, &ctx->q->control_chunk_list, list) {
878 * F1) This means that until such time as the ASCONF
879 * containing the add is acknowledged, the sender MUST
880 * NOT use the new IP address as a source for ANY SCTP
881 * packet except on carrying an ASCONF Chunk.
883 if (ctx->asoc->src_out_of_asoc_ok &&
884 chunk->chunk_hdr->type != SCTP_CID_ASCONF)
887 list_del_init(&chunk->list);
889 /* Pick the right transport to use. Should always be true for
890 * the first chunk as we don't have a transport by then.
892 sctp_outq_select_transport(ctx, chunk);
894 switch (chunk->chunk_hdr->type) {
897 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN
898 * COMPLETE with any other chunks. [Send them immediately.]
901 case SCTP_CID_INIT_ACK:
902 case SCTP_CID_SHUTDOWN_COMPLETE:
903 error = sctp_packet_singleton(ctx->transport, chunk,
906 ctx->asoc->base.sk->sk_err = -error;
912 if (sctp_test_T_bit(chunk))
913 ctx->packet->vtag = ctx->asoc->c.my_vtag;
916 /* The following chunks are "response" chunks, i.e.
917 * they are generated in response to something we
918 * received. If we are sending these, then we can
919 * send only 1 packet containing these chunks.
921 case SCTP_CID_HEARTBEAT_ACK:
922 case SCTP_CID_SHUTDOWN_ACK:
923 case SCTP_CID_COOKIE_ACK:
924 case SCTP_CID_COOKIE_ECHO:
926 case SCTP_CID_ECN_CWR:
927 case SCTP_CID_ASCONF_ACK:
932 case SCTP_CID_HEARTBEAT:
933 case SCTP_CID_SHUTDOWN:
934 case SCTP_CID_ECN_ECNE:
935 case SCTP_CID_ASCONF:
936 case SCTP_CID_FWD_TSN:
937 case SCTP_CID_I_FWD_TSN:
938 case SCTP_CID_RECONF:
939 status = sctp_packet_transmit_chunk(ctx->packet, chunk,
940 one_packet, ctx->gfp);
941 if (status != SCTP_XMIT_OK) {
942 /* put the chunk back */
943 list_add(&chunk->list, &ctx->q->control_chunk_list);
947 ctx->asoc->stats.octrlchunks++;
948 /* PR-SCTP C5) If a FORWARD TSN is sent, the
949 * sender MUST assure that at least one T3-rtx
952 if (chunk->chunk_hdr->type == SCTP_CID_FWD_TSN ||
953 chunk->chunk_hdr->type == SCTP_CID_I_FWD_TSN) {
954 sctp_transport_reset_t3_rtx(ctx->transport);
955 ctx->transport->last_time_sent = jiffies;
958 if (chunk == ctx->asoc->strreset_chunk)
959 sctp_transport_reset_reconf_timer(ctx->transport);
964 /* We built a chunk with an illegal type! */
970 /* Returns false if new data shouldn't be sent */
971 static bool sctp_outq_flush_rtx(struct sctp_flush_ctx *ctx,
974 int error, start_timer = 0;
976 if (ctx->asoc->peer.retran_path->state == SCTP_UNCONFIRMED)
979 if (ctx->transport != ctx->asoc->peer.retran_path) {
980 /* Switch transports & prepare the packet. */
981 ctx->transport = ctx->asoc->peer.retran_path;
982 ctx->packet = &ctx->transport->packet;
984 if (list_empty(&ctx->transport->send_ready))
985 list_add_tail(&ctx->transport->send_ready,
986 &ctx->transport_list);
988 sctp_packet_config(ctx->packet, ctx->asoc->peer.i.init_tag,
989 ctx->asoc->peer.ecn_capable);
992 error = __sctp_outq_flush_rtx(ctx->q, ctx->packet, rtx_timeout,
993 &start_timer, ctx->gfp);
995 ctx->asoc->base.sk->sk_err = -error;
998 sctp_transport_reset_t3_rtx(ctx->transport);
999 ctx->transport->last_time_sent = jiffies;
1002 /* This can happen on COOKIE-ECHO resend. Only
1003 * one chunk can get bundled with a COOKIE-ECHO.
1005 if (ctx->packet->has_cookie_echo)
1008 /* Don't send new data if there is still data
1009 * waiting to retransmit.
1011 if (!list_empty(&ctx->q->retransmit))
1017 static void sctp_outq_flush_data(struct sctp_flush_ctx *ctx,
1020 struct sctp_chunk *chunk;
1021 enum sctp_xmit status;
1023 /* Is it OK to send data chunks? */
1024 switch (ctx->asoc->state) {
1025 case SCTP_STATE_COOKIE_ECHOED:
1026 /* Only allow bundling when this packet has a COOKIE-ECHO
1029 if (!ctx->packet || !ctx->packet->has_cookie_echo)
1033 case SCTP_STATE_ESTABLISHED:
1034 case SCTP_STATE_SHUTDOWN_PENDING:
1035 case SCTP_STATE_SHUTDOWN_RECEIVED:
1043 /* RFC 2960 6.1 Transmission of DATA Chunks
1045 * C) When the time comes for the sender to transmit,
1046 * before sending new DATA chunks, the sender MUST
1047 * first transmit any outstanding DATA chunks which
1048 * are marked for retransmission (limited by the
1051 if (!list_empty(&ctx->q->retransmit) &&
1052 !sctp_outq_flush_rtx(ctx, rtx_timeout))
1055 /* Apply Max.Burst limitation to the current transport in
1056 * case it will be used for new data. We are going to
1057 * rest it before we return, but we want to apply the limit
1058 * to the currently queued data.
1061 sctp_transport_burst_limited(ctx->transport);
1063 /* Finally, transmit new packets. */
1064 while ((chunk = sctp_outq_dequeue_data(ctx->q)) != NULL) {
1065 __u32 sid = ntohs(chunk->subh.data_hdr->stream);
1066 __u8 stream_state = SCTP_SO(&ctx->asoc->stream, sid)->state;
1068 /* Has this chunk expired? */
1069 if (sctp_chunk_abandoned(chunk)) {
1070 sctp_sched_dequeue_done(ctx->q, chunk);
1071 sctp_chunk_fail(chunk, 0);
1072 sctp_chunk_free(chunk);
1076 if (stream_state == SCTP_STREAM_CLOSED) {
1077 sctp_outq_head_data(ctx->q, chunk);
1081 sctp_outq_select_transport(ctx, chunk);
1083 pr_debug("%s: outq:%p, chunk:%p[%s], tx-tsn:0x%x skb->head:%p skb->users:%d\n",
1084 __func__, ctx->q, chunk, chunk && chunk->chunk_hdr ?
1085 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) :
1086 "illegal chunk", ntohl(chunk->subh.data_hdr->tsn),
1087 chunk->skb ? chunk->skb->head : NULL, chunk->skb ?
1088 refcount_read(&chunk->skb->users) : -1);
1090 /* Add the chunk to the packet. */
1091 status = sctp_packet_transmit_chunk(ctx->packet, chunk, 0,
1093 if (status != SCTP_XMIT_OK) {
1094 /* We could not append this chunk, so put
1095 * the chunk back on the output queue.
1097 pr_debug("%s: could not transmit tsn:0x%x, status:%d\n",
1098 __func__, ntohl(chunk->subh.data_hdr->tsn),
1101 sctp_outq_head_data(ctx->q, chunk);
1105 /* The sender is in the SHUTDOWN-PENDING state,
1106 * The sender MAY set the I-bit in the DATA
1109 if (ctx->asoc->state == SCTP_STATE_SHUTDOWN_PENDING)
1110 chunk->chunk_hdr->flags |= SCTP_DATA_SACK_IMM;
1111 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED)
1112 ctx->asoc->stats.ouodchunks++;
1114 ctx->asoc->stats.oodchunks++;
1116 /* Only now it's safe to consider this
1117 * chunk as sent, sched-wise.
1119 sctp_sched_dequeue_done(ctx->q, chunk);
1121 list_add_tail(&chunk->transmitted_list,
1122 &ctx->transport->transmitted);
1124 sctp_transport_reset_t3_rtx(ctx->transport);
1125 ctx->transport->last_time_sent = jiffies;
1127 /* Only let one DATA chunk get bundled with a
1128 * COOKIE-ECHO chunk.
1130 if (ctx->packet->has_cookie_echo)
1135 static void sctp_outq_flush_transports(struct sctp_flush_ctx *ctx)
1137 struct list_head *ltransport;
1138 struct sctp_packet *packet;
1139 struct sctp_transport *t;
1142 while ((ltransport = sctp_list_dequeue(&ctx->transport_list)) != NULL) {
1143 t = list_entry(ltransport, struct sctp_transport, send_ready);
1144 packet = &t->packet;
1145 if (!sctp_packet_empty(packet)) {
1146 error = sctp_packet_transmit(packet, ctx->gfp);
1148 ctx->q->asoc->base.sk->sk_err = -error;
1151 /* Clear the burst limited state, if any */
1152 sctp_transport_burst_reset(t);
1156 /* Try to flush an outqueue.
1158 * Description: Send everything in q which we legally can, subject to
1159 * congestion limitations.
1160 * * Note: This function can be called from multiple contexts so appropriate
1161 * locking concerns must be made. Today we use the sock lock to protect
1165 static void sctp_outq_flush(struct sctp_outq *q, int rtx_timeout, gfp_t gfp)
1167 struct sctp_flush_ctx ctx = {
1170 .transport_list = LIST_HEAD_INIT(ctx.transport_list),
1178 * When bundling control chunks with DATA chunks, an
1179 * endpoint MUST place control chunks first in the outbound
1180 * SCTP packet. The transmitter MUST transmit DATA chunks
1181 * within a SCTP packet in increasing order of TSN.
1185 sctp_outq_flush_ctrl(&ctx);
1187 if (q->asoc->src_out_of_asoc_ok)
1188 goto sctp_flush_out;
1190 sctp_outq_flush_data(&ctx, rtx_timeout);
1194 sctp_outq_flush_transports(&ctx);
1197 /* Update unack_data based on the incoming SACK chunk */
1198 static void sctp_sack_update_unack_data(struct sctp_association *assoc,
1199 struct sctp_sackhdr *sack)
1201 union sctp_sack_variable *frags;
1205 unack_data = assoc->next_tsn - assoc->ctsn_ack_point - 1;
1207 frags = sack->variable;
1208 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); i++) {
1209 unack_data -= ((ntohs(frags[i].gab.end) -
1210 ntohs(frags[i].gab.start) + 1));
1213 assoc->unack_data = unack_data;
1216 /* This is where we REALLY process a SACK.
1218 * Process the SACK against the outqueue. Mostly, this just frees
1219 * things off the transmitted queue.
1221 int sctp_outq_sack(struct sctp_outq *q, struct sctp_chunk *chunk)
1223 struct sctp_association *asoc = q->asoc;
1224 struct sctp_sackhdr *sack = chunk->subh.sack_hdr;
1225 struct sctp_transport *transport;
1226 struct sctp_chunk *tchunk = NULL;
1227 struct list_head *lchunk, *transport_list, *temp;
1228 union sctp_sack_variable *frags = sack->variable;
1229 __u32 sack_ctsn, ctsn, tsn;
1230 __u32 highest_tsn, highest_new_tsn;
1232 unsigned int outstanding;
1233 struct sctp_transport *primary = asoc->peer.primary_path;
1234 int count_of_newacks = 0;
1238 /* Grab the association's destination address list. */
1239 transport_list = &asoc->peer.transport_addr_list;
1241 sack_ctsn = ntohl(sack->cum_tsn_ack);
1242 gap_ack_blocks = ntohs(sack->num_gap_ack_blocks);
1243 asoc->stats.gapcnt += gap_ack_blocks;
1245 * SFR-CACC algorithm:
1246 * On receipt of a SACK the sender SHOULD execute the
1247 * following statements.
1249 * 1) If the cumulative ack in the SACK passes next tsn_at_change
1250 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be
1251 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for
1253 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE
1254 * is set the receiver of the SACK MUST take the following actions:
1256 * A) Initialize the cacc_saw_newack to 0 for all destination
1259 * Only bother if changeover_active is set. Otherwise, this is
1260 * totally suboptimal to do on every SACK.
1262 if (primary->cacc.changeover_active) {
1263 u8 clear_cycling = 0;
1265 if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) {
1266 primary->cacc.changeover_active = 0;
1270 if (clear_cycling || gap_ack_blocks) {
1271 list_for_each_entry(transport, transport_list,
1274 transport->cacc.cycling_changeover = 0;
1276 transport->cacc.cacc_saw_newack = 0;
1281 /* Get the highest TSN in the sack. */
1282 highest_tsn = sack_ctsn;
1284 highest_tsn += ntohs(frags[gap_ack_blocks - 1].gab.end);
1286 if (TSN_lt(asoc->highest_sacked, highest_tsn))
1287 asoc->highest_sacked = highest_tsn;
1289 highest_new_tsn = sack_ctsn;
1291 /* Run through the retransmit queue. Credit bytes received
1292 * and free those chunks that we can.
1294 sctp_check_transmitted(q, &q->retransmit, NULL, NULL, sack, &highest_new_tsn);
1296 /* Run through the transmitted queue.
1297 * Credit bytes received and free those chunks which we can.
1299 * This is a MASSIVE candidate for optimization.
1301 list_for_each_entry(transport, transport_list, transports) {
1302 sctp_check_transmitted(q, &transport->transmitted,
1303 transport, &chunk->source, sack,
1306 * SFR-CACC algorithm:
1307 * C) Let count_of_newacks be the number of
1308 * destinations for which cacc_saw_newack is set.
1310 if (transport->cacc.cacc_saw_newack)
1314 /* Move the Cumulative TSN Ack Point if appropriate. */
1315 if (TSN_lt(asoc->ctsn_ack_point, sack_ctsn)) {
1316 asoc->ctsn_ack_point = sack_ctsn;
1320 if (gap_ack_blocks) {
1322 if (asoc->fast_recovery && accum_moved)
1323 highest_new_tsn = highest_tsn;
1325 list_for_each_entry(transport, transport_list, transports)
1326 sctp_mark_missing(q, &transport->transmitted, transport,
1327 highest_new_tsn, count_of_newacks);
1330 /* Update unack_data field in the assoc. */
1331 sctp_sack_update_unack_data(asoc, sack);
1333 ctsn = asoc->ctsn_ack_point;
1335 /* Throw away stuff rotting on the sack queue. */
1336 list_for_each_safe(lchunk, temp, &q->sacked) {
1337 tchunk = list_entry(lchunk, struct sctp_chunk,
1339 tsn = ntohl(tchunk->subh.data_hdr->tsn);
1340 if (TSN_lte(tsn, ctsn)) {
1341 list_del_init(&tchunk->transmitted_list);
1342 if (asoc->peer.prsctp_capable &&
1343 SCTP_PR_PRIO_ENABLED(chunk->sinfo.sinfo_flags))
1344 asoc->sent_cnt_removable--;
1345 sctp_chunk_free(tchunk);
1349 /* ii) Set rwnd equal to the newly received a_rwnd minus the
1350 * number of bytes still outstanding after processing the
1351 * Cumulative TSN Ack and the Gap Ack Blocks.
1354 sack_a_rwnd = ntohl(sack->a_rwnd);
1355 asoc->peer.zero_window_announced = !sack_a_rwnd;
1356 outstanding = q->outstanding_bytes;
1358 if (outstanding < sack_a_rwnd)
1359 sack_a_rwnd -= outstanding;
1363 asoc->peer.rwnd = sack_a_rwnd;
1365 asoc->stream.si->generate_ftsn(q, sack_ctsn);
1367 pr_debug("%s: sack cumulative tsn ack:0x%x\n", __func__, sack_ctsn);
1368 pr_debug("%s: cumulative tsn ack of assoc:%p is 0x%x, "
1369 "advertised peer ack point:0x%x\n", __func__, asoc, ctsn,
1370 asoc->adv_peer_ack_point);
1372 return sctp_outq_is_empty(q);
1375 /* Is the outqueue empty?
1376 * The queue is empty when we have not pending data, no in-flight data
1377 * and nothing pending retransmissions.
1379 int sctp_outq_is_empty(const struct sctp_outq *q)
1381 return q->out_qlen == 0 && q->outstanding_bytes == 0 &&
1382 list_empty(&q->retransmit);
1385 /********************************************************************
1386 * 2nd Level Abstractions
1387 ********************************************************************/
1389 /* Go through a transport's transmitted list or the association's retransmit
1390 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked.
1391 * The retransmit list will not have an associated transport.
1393 * I added coherent debug information output. --xguo
1395 * Instead of printing 'sacked' or 'kept' for each TSN on the
1396 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5.
1397 * KEPT TSN6-TSN7, etc.
1399 static void sctp_check_transmitted(struct sctp_outq *q,
1400 struct list_head *transmitted_queue,
1401 struct sctp_transport *transport,
1402 union sctp_addr *saddr,
1403 struct sctp_sackhdr *sack,
1404 __u32 *highest_new_tsn_in_sack)
1406 struct list_head *lchunk;
1407 struct sctp_chunk *tchunk;
1408 struct list_head tlist;
1412 __u8 restart_timer = 0;
1413 int bytes_acked = 0;
1414 int migrate_bytes = 0;
1415 bool forward_progress = false;
1417 sack_ctsn = ntohl(sack->cum_tsn_ack);
1419 INIT_LIST_HEAD(&tlist);
1421 /* The while loop will skip empty transmitted queues. */
1422 while (NULL != (lchunk = sctp_list_dequeue(transmitted_queue))) {
1423 tchunk = list_entry(lchunk, struct sctp_chunk,
1426 if (sctp_chunk_abandoned(tchunk)) {
1427 /* Move the chunk to abandoned list. */
1428 sctp_insert_list(&q->abandoned, lchunk);
1430 /* If this chunk has not been acked, stop
1431 * considering it as 'outstanding'.
1433 if (transmitted_queue != &q->retransmit &&
1434 !tchunk->tsn_gap_acked) {
1435 if (tchunk->transport)
1436 tchunk->transport->flight_size -=
1437 sctp_data_size(tchunk);
1438 q->outstanding_bytes -= sctp_data_size(tchunk);
1443 tsn = ntohl(tchunk->subh.data_hdr->tsn);
1444 if (sctp_acked(sack, tsn)) {
1445 /* If this queue is the retransmit queue, the
1446 * retransmit timer has already reclaimed
1447 * the outstanding bytes for this chunk, so only
1448 * count bytes associated with a transport.
1450 if (transport && !tchunk->tsn_gap_acked) {
1451 /* If this chunk is being used for RTT
1452 * measurement, calculate the RTT and update
1453 * the RTO using this value.
1455 * 6.3.1 C5) Karn's algorithm: RTT measurements
1456 * MUST NOT be made using packets that were
1457 * retransmitted (and thus for which it is
1458 * ambiguous whether the reply was for the
1459 * first instance of the packet or a later
1462 if (!sctp_chunk_retransmitted(tchunk) &&
1463 tchunk->rtt_in_progress) {
1464 tchunk->rtt_in_progress = 0;
1465 rtt = jiffies - tchunk->sent_at;
1466 sctp_transport_update_rto(transport,
1470 if (TSN_lte(tsn, sack_ctsn)) {
1472 * SFR-CACC algorithm:
1473 * 2) If the SACK contains gap acks
1474 * and the flag CHANGEOVER_ACTIVE is
1475 * set the receiver of the SACK MUST
1476 * take the following action:
1478 * B) For each TSN t being acked that
1479 * has not been acked in any SACK so
1480 * far, set cacc_saw_newack to 1 for
1481 * the destination that the TSN was
1484 if (sack->num_gap_ack_blocks &&
1485 q->asoc->peer.primary_path->cacc.
1487 transport->cacc.cacc_saw_newack
1492 /* If the chunk hasn't been marked as ACKED,
1493 * mark it and account bytes_acked if the
1494 * chunk had a valid transport (it will not
1495 * have a transport if ASCONF had deleted it
1496 * while DATA was outstanding).
1498 if (!tchunk->tsn_gap_acked) {
1499 tchunk->tsn_gap_acked = 1;
1500 if (TSN_lt(*highest_new_tsn_in_sack, tsn))
1501 *highest_new_tsn_in_sack = tsn;
1502 bytes_acked += sctp_data_size(tchunk);
1503 if (!tchunk->transport)
1504 migrate_bytes += sctp_data_size(tchunk);
1505 forward_progress = true;
1508 if (TSN_lte(tsn, sack_ctsn)) {
1509 /* RFC 2960 6.3.2 Retransmission Timer Rules
1511 * R3) Whenever a SACK is received
1512 * that acknowledges the DATA chunk
1513 * with the earliest outstanding TSN
1514 * for that address, restart T3-rtx
1515 * timer for that address with its
1519 forward_progress = true;
1521 list_add_tail(&tchunk->transmitted_list,
1524 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2
1525 * M2) Each time a SACK arrives reporting
1526 * 'Stray DATA chunk(s)' record the highest TSN
1527 * reported as newly acknowledged, call this
1528 * value 'HighestTSNinSack'. A newly
1529 * acknowledged DATA chunk is one not
1530 * previously acknowledged in a SACK.
1532 * When the SCTP sender of data receives a SACK
1533 * chunk that acknowledges, for the first time,
1534 * the receipt of a DATA chunk, all the still
1535 * unacknowledged DATA chunks whose TSN is
1536 * older than that newly acknowledged DATA
1537 * chunk, are qualified as 'Stray DATA chunks'.
1539 list_add_tail(lchunk, &tlist);
1542 if (tchunk->tsn_gap_acked) {
1543 pr_debug("%s: receiver reneged on data TSN:0x%x\n",
1546 tchunk->tsn_gap_acked = 0;
1548 if (tchunk->transport)
1549 bytes_acked -= sctp_data_size(tchunk);
1551 /* RFC 2960 6.3.2 Retransmission Timer Rules
1553 * R4) Whenever a SACK is received missing a
1554 * TSN that was previously acknowledged via a
1555 * Gap Ack Block, start T3-rtx for the
1556 * destination address to which the DATA
1557 * chunk was originally
1558 * transmitted if it is not already running.
1563 list_add_tail(lchunk, &tlist);
1569 struct sctp_association *asoc = transport->asoc;
1571 /* We may have counted DATA that was migrated
1572 * to this transport due to DEL-IP operation.
1573 * Subtract those bytes, since the were never
1574 * send on this transport and shouldn't be
1575 * credited to this transport.
1577 bytes_acked -= migrate_bytes;
1579 /* 8.2. When an outstanding TSN is acknowledged,
1580 * the endpoint shall clear the error counter of
1581 * the destination transport address to which the
1582 * DATA chunk was last sent.
1583 * The association's overall error counter is
1586 transport->error_count = 0;
1587 transport->asoc->overall_error_count = 0;
1588 forward_progress = true;
1591 * While in SHUTDOWN PENDING, we may have started
1592 * the T5 shutdown guard timer after reaching the
1593 * retransmission limit. Stop that timer as soon
1594 * as the receiver acknowledged any data.
1596 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING &&
1597 del_timer(&asoc->timers
1598 [SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD]))
1599 sctp_association_put(asoc);
1601 /* Mark the destination transport address as
1602 * active if it is not so marked.
1604 if ((transport->state == SCTP_INACTIVE ||
1605 transport->state == SCTP_UNCONFIRMED) &&
1606 sctp_cmp_addr_exact(&transport->ipaddr, saddr)) {
1607 sctp_assoc_control_transport(
1611 SCTP_RECEIVED_SACK);
1614 sctp_transport_raise_cwnd(transport, sack_ctsn,
1617 transport->flight_size -= bytes_acked;
1618 if (transport->flight_size == 0)
1619 transport->partial_bytes_acked = 0;
1620 q->outstanding_bytes -= bytes_acked + migrate_bytes;
1622 /* RFC 2960 6.1, sctpimpguide-06 2.15.2
1623 * When a sender is doing zero window probing, it
1624 * should not timeout the association if it continues
1625 * to receive new packets from the receiver. The
1626 * reason is that the receiver MAY keep its window
1627 * closed for an indefinite time.
1628 * A sender is doing zero window probing when the
1629 * receiver's advertised window is zero, and there is
1630 * only one data chunk in flight to the receiver.
1632 * Allow the association to timeout while in SHUTDOWN
1633 * PENDING or SHUTDOWN RECEIVED in case the receiver
1634 * stays in zero window mode forever.
1636 if (!q->asoc->peer.rwnd &&
1637 !list_empty(&tlist) &&
1638 (sack_ctsn+2 == q->asoc->next_tsn) &&
1639 q->asoc->state < SCTP_STATE_SHUTDOWN_PENDING) {
1640 pr_debug("%s: sack received for zero window "
1641 "probe:%u\n", __func__, sack_ctsn);
1643 q->asoc->overall_error_count = 0;
1644 transport->error_count = 0;
1648 /* RFC 2960 6.3.2 Retransmission Timer Rules
1650 * R2) Whenever all outstanding data sent to an address have
1651 * been acknowledged, turn off the T3-rtx timer of that
1654 if (!transport->flight_size) {
1655 if (del_timer(&transport->T3_rtx_timer))
1656 sctp_transport_put(transport);
1657 } else if (restart_timer) {
1658 if (!mod_timer(&transport->T3_rtx_timer,
1659 jiffies + transport->rto))
1660 sctp_transport_hold(transport);
1663 if (forward_progress) {
1665 sctp_transport_dst_confirm(transport);
1669 list_splice(&tlist, transmitted_queue);
1672 /* Mark chunks as missing and consequently may get retransmitted. */
1673 static void sctp_mark_missing(struct sctp_outq *q,
1674 struct list_head *transmitted_queue,
1675 struct sctp_transport *transport,
1676 __u32 highest_new_tsn_in_sack,
1677 int count_of_newacks)
1679 struct sctp_chunk *chunk;
1681 char do_fast_retransmit = 0;
1682 struct sctp_association *asoc = q->asoc;
1683 struct sctp_transport *primary = asoc->peer.primary_path;
1685 list_for_each_entry(chunk, transmitted_queue, transmitted_list) {
1687 tsn = ntohl(chunk->subh.data_hdr->tsn);
1689 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all
1690 * 'Unacknowledged TSN's', if the TSN number of an
1691 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack'
1692 * value, increment the 'TSN.Missing.Report' count on that
1693 * chunk if it has NOT been fast retransmitted or marked for
1694 * fast retransmit already.
1696 if (chunk->fast_retransmit == SCTP_CAN_FRTX &&
1697 !chunk->tsn_gap_acked &&
1698 TSN_lt(tsn, highest_new_tsn_in_sack)) {
1700 /* SFR-CACC may require us to skip marking
1701 * this chunk as missing.
1703 if (!transport || !sctp_cacc_skip(primary,
1705 count_of_newacks, tsn)) {
1706 chunk->tsn_missing_report++;
1708 pr_debug("%s: tsn:0x%x missing counter:%d\n",
1709 __func__, tsn, chunk->tsn_missing_report);
1713 * M4) If any DATA chunk is found to have a
1714 * 'TSN.Missing.Report'
1715 * value larger than or equal to 3, mark that chunk for
1716 * retransmission and start the fast retransmit procedure.
1719 if (chunk->tsn_missing_report >= 3) {
1720 chunk->fast_retransmit = SCTP_NEED_FRTX;
1721 do_fast_retransmit = 1;
1726 if (do_fast_retransmit)
1727 sctp_retransmit(q, transport, SCTP_RTXR_FAST_RTX);
1729 pr_debug("%s: transport:%p, cwnd:%d, ssthresh:%d, "
1730 "flight_size:%d, pba:%d\n", __func__, transport,
1731 transport->cwnd, transport->ssthresh,
1732 transport->flight_size, transport->partial_bytes_acked);
1736 /* Is the given TSN acked by this packet? */
1737 static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn)
1739 __u32 ctsn = ntohl(sack->cum_tsn_ack);
1740 union sctp_sack_variable *frags;
1741 __u16 tsn_offset, blocks;
1744 if (TSN_lte(tsn, ctsn))
1747 /* 3.3.4 Selective Acknowledgment (SACK) (3):
1750 * These fields contain the Gap Ack Blocks. They are repeated
1751 * for each Gap Ack Block up to the number of Gap Ack Blocks
1752 * defined in the Number of Gap Ack Blocks field. All DATA
1753 * chunks with TSNs greater than or equal to (Cumulative TSN
1754 * Ack + Gap Ack Block Start) and less than or equal to
1755 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack
1756 * Block are assumed to have been received correctly.
1759 frags = sack->variable;
1760 blocks = ntohs(sack->num_gap_ack_blocks);
1761 tsn_offset = tsn - ctsn;
1762 for (i = 0; i < blocks; ++i) {
1763 if (tsn_offset >= ntohs(frags[i].gab.start) &&
1764 tsn_offset <= ntohs(frags[i].gab.end))
1773 static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip *skiplist,
1774 int nskips, __be16 stream)
1778 for (i = 0; i < nskips; i++) {
1779 if (skiplist[i].stream == stream)
1785 /* Create and add a fwdtsn chunk to the outq's control queue if needed. */
1786 void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 ctsn)
1788 struct sctp_association *asoc = q->asoc;
1789 struct sctp_chunk *ftsn_chunk = NULL;
1790 struct sctp_fwdtsn_skip ftsn_skip_arr[10];
1794 struct sctp_chunk *chunk;
1795 struct list_head *lchunk, *temp;
1797 if (!asoc->peer.prsctp_capable)
1800 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the
1803 * If (Advanced.Peer.Ack.Point < SackCumAck), then update
1804 * Advanced.Peer.Ack.Point to be equal to SackCumAck.
1806 if (TSN_lt(asoc->adv_peer_ack_point, ctsn))
1807 asoc->adv_peer_ack_point = ctsn;
1809 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point"
1810 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as
1811 * the chunk next in the out-queue space is marked as "abandoned" as
1812 * shown in the following example:
1814 * Assuming that a SACK arrived with the Cumulative TSN ACK 102
1815 * and the Advanced.Peer.Ack.Point is updated to this value:
1817 * out-queue at the end of ==> out-queue after Adv.Ack.Point
1818 * normal SACK processing local advancement
1820 * Adv.Ack.Pt-> 102 acked 102 acked
1821 * 103 abandoned 103 abandoned
1822 * 104 abandoned Adv.Ack.P-> 104 abandoned
1824 * 106 acked 106 acked
1827 * In this example, the data sender successfully advanced the
1828 * "Advanced.Peer.Ack.Point" from 102 to 104 locally.
1830 list_for_each_safe(lchunk, temp, &q->abandoned) {
1831 chunk = list_entry(lchunk, struct sctp_chunk,
1833 tsn = ntohl(chunk->subh.data_hdr->tsn);
1835 /* Remove any chunks in the abandoned queue that are acked by
1838 if (TSN_lte(tsn, ctsn)) {
1839 list_del_init(lchunk);
1840 sctp_chunk_free(chunk);
1842 if (TSN_lte(tsn, asoc->adv_peer_ack_point+1)) {
1843 asoc->adv_peer_ack_point = tsn;
1844 if (chunk->chunk_hdr->flags &
1845 SCTP_DATA_UNORDERED)
1847 skip_pos = sctp_get_skip_pos(&ftsn_skip_arr[0],
1849 chunk->subh.data_hdr->stream);
1850 ftsn_skip_arr[skip_pos].stream =
1851 chunk->subh.data_hdr->stream;
1852 ftsn_skip_arr[skip_pos].ssn =
1853 chunk->subh.data_hdr->ssn;
1854 if (skip_pos == nskips)
1863 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point"
1864 * is greater than the Cumulative TSN ACK carried in the received
1865 * SACK, the data sender MUST send the data receiver a FORWARD TSN
1866 * chunk containing the latest value of the
1867 * "Advanced.Peer.Ack.Point".
1869 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD
1870 * list each stream and sequence number in the forwarded TSN. This
1871 * information will enable the receiver to easily find any
1872 * stranded TSN's waiting on stream reorder queues. Each stream
1873 * SHOULD only be reported once; this means that if multiple
1874 * abandoned messages occur in the same stream then only the
1875 * highest abandoned stream sequence number is reported. If the
1876 * total size of the FORWARD TSN does NOT fit in a single MTU then
1877 * the sender of the FORWARD TSN SHOULD lower the
1878 * Advanced.Peer.Ack.Point to the last TSN that will fit in a
1881 if (asoc->adv_peer_ack_point > ctsn)
1882 ftsn_chunk = sctp_make_fwdtsn(asoc, asoc->adv_peer_ack_point,
1883 nskips, &ftsn_skip_arr[0]);
1886 list_add_tail(&ftsn_chunk->list, &q->control_chunk_list);
1887 SCTP_INC_STATS(sock_net(asoc->base.sk), SCTP_MIB_OUTCTRLCHUNKS);