1 /* SCTP kernel reference Implementation
2 * (C) Copyright IBM Corp. 2001, 2004
3 * Copyright (c) 1999-2000 Cisco, Inc.
4 * Copyright (c) 1999-2001 Motorola, Inc.
5 * Copyright (c) 2001-2003 Intel Corp.
7 * This file is part of the SCTP kernel reference Implementation
9 * These functions implement the sctp_outq class. The outqueue handles
10 * bundling and queueing of outgoing SCTP chunks.
12 * The SCTP reference implementation is free software;
13 * you can redistribute it and/or modify it under the terms of
14 * the GNU General Public License as published by
15 * the Free Software Foundation; either version 2, or (at your option)
18 * The SCTP reference implementation is distributed in the hope that it
19 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
20 * ************************
21 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
22 * See the GNU General Public License for more details.
24 * You should have received a copy of the GNU General Public License
25 * along with GNU CC; see the file COPYING. If not, write to
26 * the Free Software Foundation, 59 Temple Place - Suite 330,
27 * Boston, MA 02111-1307, USA.
29 * Please send any bug reports or fixes you make to the
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 /* Add data to the front of the queue. */
75 static inline void sctp_outq_head_data(struct sctp_outq
*q
,
76 struct sctp_chunk
*ch
)
78 list_add(&ch
->list
, &q
->out_chunk_list
);
79 q
->out_qlen
+= ch
->skb
->len
;
83 /* Take data from the front of the queue. */
84 static inline struct sctp_chunk
*sctp_outq_dequeue_data(struct sctp_outq
*q
)
86 struct sctp_chunk
*ch
= NULL
;
88 if (!list_empty(&q
->out_chunk_list
)) {
89 struct list_head
*entry
= q
->out_chunk_list
.next
;
91 ch
= list_entry(entry
, struct sctp_chunk
, list
);
93 q
->out_qlen
-= ch
->skb
->len
;
97 /* Add data chunk to the end of the queue. */
98 static inline void sctp_outq_tail_data(struct sctp_outq
*q
,
99 struct sctp_chunk
*ch
)
101 list_add_tail(&ch
->list
, &q
->out_chunk_list
);
102 q
->out_qlen
+= ch
->skb
->len
;
107 * SFR-CACC algorithm:
108 * D) If count_of_newacks is greater than or equal to 2
109 * and t was not sent to the current primary then the
110 * sender MUST NOT increment missing report count for t.
112 static inline int sctp_cacc_skip_3_1_d(struct sctp_transport
*primary
,
113 struct sctp_transport
*transport
,
114 int count_of_newacks
)
116 if (count_of_newacks
>=2 && transport
!= primary
)
122 * SFR-CACC algorithm:
123 * F) If count_of_newacks is less than 2, let d be the
124 * destination to which t was sent. If cacc_saw_newack
125 * is 0 for destination d, then the sender MUST NOT
126 * increment missing report count for t.
128 static inline int sctp_cacc_skip_3_1_f(struct sctp_transport
*transport
,
129 int count_of_newacks
)
131 if (count_of_newacks
< 2 && !transport
->cacc
.cacc_saw_newack
)
137 * SFR-CACC algorithm:
138 * 3.1) If CYCLING_CHANGEOVER is 0, the sender SHOULD
139 * execute steps C, D, F.
141 * C has been implemented in sctp_outq_sack
143 static inline int sctp_cacc_skip_3_1(struct sctp_transport
*primary
,
144 struct sctp_transport
*transport
,
145 int count_of_newacks
)
147 if (!primary
->cacc
.cycling_changeover
) {
148 if (sctp_cacc_skip_3_1_d(primary
, transport
, count_of_newacks
))
150 if (sctp_cacc_skip_3_1_f(transport
, count_of_newacks
))
158 * SFR-CACC algorithm:
159 * 3.2) Else if CYCLING_CHANGEOVER is 1, and t is less
160 * than next_tsn_at_change of the current primary, then
161 * the sender MUST NOT increment missing report count
164 static inline int sctp_cacc_skip_3_2(struct sctp_transport
*primary
, __u32 tsn
)
166 if (primary
->cacc
.cycling_changeover
&&
167 TSN_lt(tsn
, primary
->cacc
.next_tsn_at_change
))
173 * SFR-CACC algorithm:
174 * 3) If the missing report count for TSN t is to be
175 * incremented according to [RFC2960] and
176 * [SCTP_STEWART-2002], and CHANGEOVER_ACTIVE is set,
177 * then the sender MUST futher execute steps 3.1 and
178 * 3.2 to determine if the missing report count for
179 * TSN t SHOULD NOT be incremented.
181 * 3.3) If 3.1 and 3.2 do not dictate that the missing
182 * report count for t should not be incremented, then
183 * the sender SOULD increment missing report count for
184 * t (according to [RFC2960] and [SCTP_STEWART_2002]).
186 static inline int sctp_cacc_skip(struct sctp_transport
*primary
,
187 struct sctp_transport
*transport
,
188 int count_of_newacks
,
191 if (primary
->cacc
.changeover_active
&&
192 (sctp_cacc_skip_3_1(primary
, transport
, count_of_newacks
)
193 || sctp_cacc_skip_3_2(primary
, tsn
)))
198 /* Initialize an existing sctp_outq. This does the boring stuff.
199 * You still need to define handlers if you really want to DO
200 * something with this structure...
202 void sctp_outq_init(struct sctp_association
*asoc
, struct sctp_outq
*q
)
205 INIT_LIST_HEAD(&q
->out_chunk_list
);
206 INIT_LIST_HEAD(&q
->control_chunk_list
);
207 INIT_LIST_HEAD(&q
->retransmit
);
208 INIT_LIST_HEAD(&q
->sacked
);
209 INIT_LIST_HEAD(&q
->abandoned
);
211 q
->outstanding_bytes
= 0;
219 /* Free the outqueue structure and any related pending chunks.
221 void sctp_outq_teardown(struct sctp_outq
*q
)
223 struct sctp_transport
*transport
;
224 struct list_head
*lchunk
, *pos
, *temp
;
225 struct sctp_chunk
*chunk
, *tmp
;
227 /* Throw away unacknowledged chunks. */
228 list_for_each(pos
, &q
->asoc
->peer
.transport_addr_list
) {
229 transport
= list_entry(pos
, struct sctp_transport
, transports
);
230 while ((lchunk
= sctp_list_dequeue(&transport
->transmitted
)) != NULL
) {
231 chunk
= list_entry(lchunk
, struct sctp_chunk
,
233 /* Mark as part of a failed message. */
234 sctp_chunk_fail(chunk
, q
->error
);
235 sctp_chunk_free(chunk
);
239 /* Throw away chunks that have been gap ACKed. */
240 list_for_each_safe(lchunk
, temp
, &q
->sacked
) {
241 list_del_init(lchunk
);
242 chunk
= list_entry(lchunk
, struct sctp_chunk
,
244 sctp_chunk_fail(chunk
, q
->error
);
245 sctp_chunk_free(chunk
);
248 /* Throw away any chunks in the retransmit queue. */
249 list_for_each_safe(lchunk
, temp
, &q
->retransmit
) {
250 list_del_init(lchunk
);
251 chunk
= list_entry(lchunk
, struct sctp_chunk
,
253 sctp_chunk_fail(chunk
, q
->error
);
254 sctp_chunk_free(chunk
);
257 /* Throw away any chunks that are in the abandoned queue. */
258 list_for_each_safe(lchunk
, temp
, &q
->abandoned
) {
259 list_del_init(lchunk
);
260 chunk
= list_entry(lchunk
, struct sctp_chunk
,
262 sctp_chunk_fail(chunk
, q
->error
);
263 sctp_chunk_free(chunk
);
266 /* Throw away any leftover data chunks. */
267 while ((chunk
= sctp_outq_dequeue_data(q
)) != NULL
) {
269 /* Mark as send failure. */
270 sctp_chunk_fail(chunk
, q
->error
);
271 sctp_chunk_free(chunk
);
276 /* Throw away any leftover control chunks. */
277 list_for_each_entry_safe(chunk
, tmp
, &q
->control_chunk_list
, list
) {
278 list_del_init(&chunk
->list
);
279 sctp_chunk_free(chunk
);
283 /* Free the outqueue structure and any related pending chunks. */
284 void sctp_outq_free(struct sctp_outq
*q
)
286 /* Throw away leftover chunks. */
287 sctp_outq_teardown(q
);
289 /* If we were kmalloc()'d, free the memory. */
294 /* Put a new chunk in an sctp_outq. */
295 int sctp_outq_tail(struct sctp_outq
*q
, struct sctp_chunk
*chunk
)
299 SCTP_DEBUG_PRINTK("sctp_outq_tail(%p, %p[%s])\n",
300 q
, chunk
, chunk
&& chunk
->chunk_hdr
?
301 sctp_cname(SCTP_ST_CHUNK(chunk
->chunk_hdr
->type
))
304 /* If it is data, queue it up, otherwise, send it
307 if (SCTP_CID_DATA
== chunk
->chunk_hdr
->type
) {
308 /* Is it OK to queue data chunks? */
309 /* From 9. Termination of Association
311 * When either endpoint performs a shutdown, the
312 * association on each peer will stop accepting new
313 * data from its user and only deliver data in queue
314 * at the time of sending or receiving the SHUTDOWN
317 switch (q
->asoc
->state
) {
318 case SCTP_STATE_EMPTY
:
319 case SCTP_STATE_CLOSED
:
320 case SCTP_STATE_SHUTDOWN_PENDING
:
321 case SCTP_STATE_SHUTDOWN_SENT
:
322 case SCTP_STATE_SHUTDOWN_RECEIVED
:
323 case SCTP_STATE_SHUTDOWN_ACK_SENT
:
324 /* Cannot send after transport endpoint shutdown */
329 SCTP_DEBUG_PRINTK("outqueueing (%p, %p[%s])\n",
330 q
, chunk
, chunk
&& chunk
->chunk_hdr
?
331 sctp_cname(SCTP_ST_CHUNK(chunk
->chunk_hdr
->type
))
334 sctp_outq_tail_data(q
, chunk
);
335 if (chunk
->chunk_hdr
->flags
& SCTP_DATA_UNORDERED
)
336 SCTP_INC_STATS(SCTP_MIB_OUTUNORDERCHUNKS
);
338 SCTP_INC_STATS(SCTP_MIB_OUTORDERCHUNKS
);
343 list_add_tail(&chunk
->list
, &q
->control_chunk_list
);
344 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS
);
351 error
= sctp_outq_flush(q
, 0);
356 /* Insert a chunk into the sorted list based on the TSNs. The retransmit list
357 * and the abandoned list are in ascending order.
359 static void sctp_insert_list(struct list_head
*head
, struct list_head
*new)
361 struct list_head
*pos
;
362 struct sctp_chunk
*nchunk
, *lchunk
;
366 nchunk
= list_entry(new, struct sctp_chunk
, transmitted_list
);
367 ntsn
= ntohl(nchunk
->subh
.data_hdr
->tsn
);
369 list_for_each(pos
, head
) {
370 lchunk
= list_entry(pos
, struct sctp_chunk
, transmitted_list
);
371 ltsn
= ntohl(lchunk
->subh
.data_hdr
->tsn
);
372 if (TSN_lt(ntsn
, ltsn
)) {
373 list_add(new, pos
->prev
);
379 list_add_tail(new, head
);
382 /* Mark all the eligible packets on a transport for retransmission. */
383 void sctp_retransmit_mark(struct sctp_outq
*q
,
384 struct sctp_transport
*transport
,
387 struct list_head
*lchunk
, *ltemp
;
388 struct sctp_chunk
*chunk
;
390 /* Walk through the specified transmitted queue. */
391 list_for_each_safe(lchunk
, ltemp
, &transport
->transmitted
) {
392 chunk
= list_entry(lchunk
, struct sctp_chunk
,
395 /* If the chunk is abandoned, move it to abandoned list. */
396 if (sctp_chunk_abandoned(chunk
)) {
397 list_del_init(lchunk
);
398 sctp_insert_list(&q
->abandoned
, lchunk
);
400 /* If this chunk has not been previousely acked,
401 * stop considering it 'outstanding'. Our peer
402 * will most likely never see it since it will
403 * not be retransmitted
405 if (!chunk
->tsn_gap_acked
) {
406 chunk
->transport
->flight_size
-=
407 sctp_data_size(chunk
);
408 q
->outstanding_bytes
-= sctp_data_size(chunk
);
409 q
->asoc
->peer
.rwnd
+= (sctp_data_size(chunk
) +
410 sizeof(struct sk_buff
));
415 /* If we are doing retransmission due to a timeout or pmtu
416 * discovery, only the chunks that are not yet acked should
417 * be added to the retransmit queue.
419 if ((reason
== SCTP_RTXR_FAST_RTX
&&
420 (chunk
->fast_retransmit
> 0)) ||
421 (reason
!= SCTP_RTXR_FAST_RTX
&& !chunk
->tsn_gap_acked
)) {
422 /* If this chunk was sent less then 1 rto ago, do not
423 * retransmit this chunk, but give the peer time
424 * to acknowlege it. Do this only when
425 * retransmitting due to T3 timeout.
427 if (reason
== SCTP_RTXR_T3_RTX
&&
428 (jiffies
- chunk
->sent_at
) < transport
->last_rto
)
431 /* RFC 2960 6.2.1 Processing a Received SACK
433 * C) Any time a DATA chunk is marked for
434 * retransmission (via either T3-rtx timer expiration
435 * (Section 6.3.3) or via fast retransmit
436 * (Section 7.2.4)), add the data size of those
437 * chunks to the rwnd.
439 q
->asoc
->peer
.rwnd
+= (sctp_data_size(chunk
) +
440 sizeof(struct sk_buff
));
441 q
->outstanding_bytes
-= sctp_data_size(chunk
);
442 transport
->flight_size
-= sctp_data_size(chunk
);
444 /* sctpimpguide-05 Section 2.8.2
445 * M5) If a T3-rtx timer expires, the
446 * 'TSN.Missing.Report' of all affected TSNs is set
449 chunk
->tsn_missing_report
= 0;
451 /* If a chunk that is being used for RTT measurement
452 * has to be retransmitted, we cannot use this chunk
453 * anymore for RTT measurements. Reset rto_pending so
454 * that a new RTT measurement is started when a new
455 * data chunk is sent.
457 if (chunk
->rtt_in_progress
) {
458 chunk
->rtt_in_progress
= 0;
459 transport
->rto_pending
= 0;
462 /* Move the chunk to the retransmit queue. The chunks
463 * on the retransmit queue are always kept in order.
465 list_del_init(lchunk
);
466 sctp_insert_list(&q
->retransmit
, lchunk
);
470 SCTP_DEBUG_PRINTK("%s: transport: %p, reason: %d, "
471 "cwnd: %d, ssthresh: %d, flight_size: %d, "
472 "pba: %d\n", __FUNCTION__
,
474 transport
->cwnd
, transport
->ssthresh
,
475 transport
->flight_size
,
476 transport
->partial_bytes_acked
);
480 /* Mark all the eligible packets on a transport for retransmission and force
483 void sctp_retransmit(struct sctp_outq
*q
, struct sctp_transport
*transport
,
484 sctp_retransmit_reason_t reason
)
489 case SCTP_RTXR_T3_RTX
:
490 SCTP_INC_STATS(SCTP_MIB_T3_RETRANSMITS
);
491 sctp_transport_lower_cwnd(transport
, SCTP_LOWER_CWND_T3_RTX
);
492 /* Update the retran path if the T3-rtx timer has expired for
493 * the current retran path.
495 if (transport
== transport
->asoc
->peer
.retran_path
)
496 sctp_assoc_update_retran_path(transport
->asoc
);
498 case SCTP_RTXR_FAST_RTX
:
499 SCTP_INC_STATS(SCTP_MIB_FAST_RETRANSMITS
);
500 sctp_transport_lower_cwnd(transport
, SCTP_LOWER_CWND_FAST_RTX
);
502 case SCTP_RTXR_PMTUD
:
503 SCTP_INC_STATS(SCTP_MIB_PMTUD_RETRANSMITS
);
505 case SCTP_RTXR_T1_RTX
:
506 SCTP_INC_STATS(SCTP_MIB_T1_RETRANSMITS
);
512 sctp_retransmit_mark(q
, transport
, reason
);
514 /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination,
515 * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by
516 * following the procedures outlined in C1 - C5.
518 sctp_generate_fwdtsn(q
, q
->asoc
->ctsn_ack_point
);
520 error
= sctp_outq_flush(q
, /* rtx_timeout */ 1);
523 q
->asoc
->base
.sk
->sk_err
= -error
;
527 * Transmit DATA chunks on the retransmit queue. Upon return from
528 * sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which
529 * need to be transmitted by the caller.
530 * We assume that pkt->transport has already been set.
532 * The return value is a normal kernel error return value.
534 static int sctp_outq_flush_rtx(struct sctp_outq
*q
, struct sctp_packet
*pkt
,
535 int rtx_timeout
, int *start_timer
)
537 struct list_head
*lqueue
;
538 struct list_head
*lchunk
, *lchunk1
;
539 struct sctp_transport
*transport
= pkt
->transport
;
541 struct sctp_chunk
*chunk
, *chunk1
;
542 struct sctp_association
*asoc
;
546 lqueue
= &q
->retransmit
;
548 /* RFC 2960 6.3.3 Handle T3-rtx Expiration
550 * E3) Determine how many of the earliest (i.e., lowest TSN)
551 * outstanding DATA chunks for the address for which the
552 * T3-rtx has expired will fit into a single packet, subject
553 * to the MTU constraint for the path corresponding to the
554 * destination transport address to which the retransmission
555 * is being sent (this may be different from the address for
556 * which the timer expires [see Section 6.4]). Call this value
557 * K. Bundle and retransmit those K DATA chunks in a single
558 * packet to the destination endpoint.
560 * [Just to be painfully clear, if we are retransmitting
561 * because a timeout just happened, we should send only ONE
562 * packet of retransmitted data.]
564 lchunk
= sctp_list_dequeue(lqueue
);
567 chunk
= list_entry(lchunk
, struct sctp_chunk
,
570 /* Make sure that Gap Acked TSNs are not retransmitted. A
571 * simple approach is just to move such TSNs out of the
572 * way and into a 'transmitted' queue and skip to the
575 if (chunk
->tsn_gap_acked
) {
576 list_add_tail(lchunk
, &transport
->transmitted
);
577 lchunk
= sctp_list_dequeue(lqueue
);
581 /* Attempt to append this chunk to the packet. */
582 status
= sctp_packet_append_chunk(pkt
, chunk
);
585 case SCTP_XMIT_PMTU_FULL
:
586 /* Send this packet. */
587 if ((error
= sctp_packet_transmit(pkt
)) == 0)
590 /* If we are retransmitting, we should only
591 * send a single packet.
594 list_add(lchunk
, lqueue
);
598 /* Bundle lchunk in the next round. */
601 case SCTP_XMIT_RWND_FULL
:
602 /* Send this packet. */
603 if ((error
= sctp_packet_transmit(pkt
)) == 0)
606 /* Stop sending DATA as there is no more room
609 list_add(lchunk
, lqueue
);
613 case SCTP_XMIT_NAGLE_DELAY
:
614 /* Send this packet. */
615 if ((error
= sctp_packet_transmit(pkt
)) == 0)
618 /* Stop sending DATA because of nagle delay. */
619 list_add(lchunk
, lqueue
);
624 /* The append was successful, so add this chunk to
625 * the transmitted list.
627 list_add_tail(lchunk
, &transport
->transmitted
);
629 /* Mark the chunk as ineligible for fast retransmit
630 * after it is retransmitted.
632 if (chunk
->fast_retransmit
> 0)
633 chunk
->fast_retransmit
= -1;
638 /* Retrieve a new chunk to bundle. */
639 lchunk
= sctp_list_dequeue(lqueue
);
643 /* If we are here due to a retransmit timeout or a fast
644 * retransmit and if there are any chunks left in the retransmit
645 * queue that could not fit in the PMTU sized packet, they need
646 * to be marked as ineligible for a subsequent fast retransmit.
648 if (rtx_timeout
&& !lchunk
) {
649 list_for_each(lchunk1
, lqueue
) {
650 chunk1
= list_entry(lchunk1
, struct sctp_chunk
,
652 if (chunk1
->fast_retransmit
> 0)
653 chunk1
->fast_retransmit
= -1;
661 /* Cork the outqueue so queued chunks are really queued. */
662 int sctp_outq_uncork(struct sctp_outq
*q
)
667 error
= sctp_outq_flush(q
, 0);
673 * Try to flush an outqueue.
675 * Description: Send everything in q which we legally can, subject to
676 * congestion limitations.
677 * * Note: This function can be called from multiple contexts so appropriate
678 * locking concerns must be made. Today we use the sock lock to protect
681 int sctp_outq_flush(struct sctp_outq
*q
, int rtx_timeout
)
683 struct sctp_packet
*packet
;
684 struct sctp_packet singleton
;
685 struct sctp_association
*asoc
= q
->asoc
;
686 __u16 sport
= asoc
->base
.bind_addr
.port
;
687 __u16 dport
= asoc
->peer
.port
;
688 __u32 vtag
= asoc
->peer
.i
.init_tag
;
689 struct sctp_transport
*transport
= NULL
;
690 struct sctp_transport
*new_transport
;
691 struct sctp_chunk
*chunk
, *tmp
;
696 /* These transports have chunks to send. */
697 struct list_head transport_list
;
698 struct list_head
*ltransport
;
700 INIT_LIST_HEAD(&transport_list
);
706 * When bundling control chunks with DATA chunks, an
707 * endpoint MUST place control chunks first in the outbound
708 * SCTP packet. The transmitter MUST transmit DATA chunks
709 * within a SCTP packet in increasing order of TSN.
713 list_for_each_entry_safe(chunk
, tmp
, &q
->control_chunk_list
, list
) {
714 list_del_init(&chunk
->list
);
716 /* Pick the right transport to use. */
717 new_transport
= chunk
->transport
;
719 if (!new_transport
) {
720 new_transport
= asoc
->peer
.active_path
;
721 } else if ((new_transport
->state
== SCTP_INACTIVE
) ||
722 (new_transport
->state
== SCTP_UNCONFIRMED
)) {
723 /* If the chunk is Heartbeat or Heartbeat Ack,
724 * send it to chunk->transport, even if it's
727 * 3.3.6 Heartbeat Acknowledgement:
729 * A HEARTBEAT ACK is always sent to the source IP
730 * address of the IP datagram containing the
731 * HEARTBEAT chunk to which this ack is responding.
734 if (chunk
->chunk_hdr
->type
!= SCTP_CID_HEARTBEAT
&&
735 chunk
->chunk_hdr
->type
!= SCTP_CID_HEARTBEAT_ACK
)
736 new_transport
= asoc
->peer
.active_path
;
739 /* Are we switching transports?
740 * Take care of transport locks.
742 if (new_transport
!= transport
) {
743 transport
= new_transport
;
744 if (list_empty(&transport
->send_ready
)) {
745 list_add_tail(&transport
->send_ready
,
748 packet
= &transport
->packet
;
749 sctp_packet_config(packet
, vtag
,
750 asoc
->peer
.ecn_capable
);
753 switch (chunk
->chunk_hdr
->type
) {
757 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN
758 * COMPLETE with any other chunks. [Send them immediately.]
761 case SCTP_CID_INIT_ACK
:
762 case SCTP_CID_SHUTDOWN_COMPLETE
:
763 sctp_packet_init(&singleton
, transport
, sport
, dport
);
764 sctp_packet_config(&singleton
, vtag
, 0);
765 sctp_packet_append_chunk(&singleton
, chunk
);
766 error
= sctp_packet_transmit(&singleton
);
773 case SCTP_CID_HEARTBEAT
:
774 case SCTP_CID_HEARTBEAT_ACK
:
775 case SCTP_CID_SHUTDOWN
:
776 case SCTP_CID_SHUTDOWN_ACK
:
778 case SCTP_CID_COOKIE_ECHO
:
779 case SCTP_CID_COOKIE_ACK
:
780 case SCTP_CID_ECN_ECNE
:
781 case SCTP_CID_ECN_CWR
:
782 case SCTP_CID_ASCONF
:
783 case SCTP_CID_ASCONF_ACK
:
784 case SCTP_CID_FWD_TSN
:
785 sctp_packet_transmit_chunk(packet
, chunk
);
789 /* We built a chunk with an illegal type! */
794 /* Is it OK to send data chunks? */
795 switch (asoc
->state
) {
796 case SCTP_STATE_COOKIE_ECHOED
:
797 /* Only allow bundling when this packet has a COOKIE-ECHO
800 if (!packet
|| !packet
->has_cookie_echo
)
804 case SCTP_STATE_ESTABLISHED
:
805 case SCTP_STATE_SHUTDOWN_PENDING
:
806 case SCTP_STATE_SHUTDOWN_RECEIVED
:
808 * RFC 2960 6.1 Transmission of DATA Chunks
810 * C) When the time comes for the sender to transmit,
811 * before sending new DATA chunks, the sender MUST
812 * first transmit any outstanding DATA chunks which
813 * are marked for retransmission (limited by the
816 if (!list_empty(&q
->retransmit
)) {
817 if (transport
== asoc
->peer
.retran_path
)
820 /* Switch transports & prepare the packet. */
822 transport
= asoc
->peer
.retran_path
;
824 if (list_empty(&transport
->send_ready
)) {
825 list_add_tail(&transport
->send_ready
,
829 packet
= &transport
->packet
;
830 sctp_packet_config(packet
, vtag
,
831 asoc
->peer
.ecn_capable
);
833 error
= sctp_outq_flush_rtx(q
, packet
,
834 rtx_timeout
, &start_timer
);
837 sctp_transport_reset_timers(transport
);
839 /* This can happen on COOKIE-ECHO resend. Only
840 * one chunk can get bundled with a COOKIE-ECHO.
842 if (packet
->has_cookie_echo
)
845 /* Don't send new data if there is still data
846 * waiting to retransmit.
848 if (!list_empty(&q
->retransmit
))
852 /* Finally, transmit new packets. */
854 while ((chunk
= sctp_outq_dequeue_data(q
)) != NULL
) {
855 /* RFC 2960 6.5 Every DATA chunk MUST carry a valid
858 if (chunk
->sinfo
.sinfo_stream
>=
859 asoc
->c
.sinit_num_ostreams
) {
861 /* Mark as failed send. */
862 sctp_chunk_fail(chunk
, SCTP_ERROR_INV_STRM
);
863 sctp_chunk_free(chunk
);
867 /* Has this chunk expired? */
868 if (sctp_chunk_abandoned(chunk
)) {
869 sctp_chunk_fail(chunk
, 0);
870 sctp_chunk_free(chunk
);
874 /* If there is a specified transport, use it.
875 * Otherwise, we want to use the active path.
877 new_transport
= chunk
->transport
;
878 if (!new_transport
||
879 ((new_transport
->state
== SCTP_INACTIVE
) ||
880 (new_transport
->state
== SCTP_UNCONFIRMED
)))
881 new_transport
= asoc
->peer
.active_path
;
883 /* Change packets if necessary. */
884 if (new_transport
!= transport
) {
885 transport
= new_transport
;
887 /* Schedule to have this transport's
890 if (list_empty(&transport
->send_ready
)) {
891 list_add_tail(&transport
->send_ready
,
895 packet
= &transport
->packet
;
896 sctp_packet_config(packet
, vtag
,
897 asoc
->peer
.ecn_capable
);
900 SCTP_DEBUG_PRINTK("sctp_outq_flush(%p, %p[%s]), ",
902 chunk
&& chunk
->chunk_hdr
?
903 sctp_cname(SCTP_ST_CHUNK(
904 chunk
->chunk_hdr
->type
))
907 SCTP_DEBUG_PRINTK("TX TSN 0x%x skb->head "
908 "%p skb->users %d.\n",
909 ntohl(chunk
->subh
.data_hdr
->tsn
),
910 chunk
->skb
?chunk
->skb
->head
: NULL
,
912 atomic_read(&chunk
->skb
->users
) : -1);
914 /* Add the chunk to the packet. */
915 status
= sctp_packet_transmit_chunk(packet
, chunk
);
918 case SCTP_XMIT_PMTU_FULL
:
919 case SCTP_XMIT_RWND_FULL
:
920 case SCTP_XMIT_NAGLE_DELAY
:
921 /* We could not append this chunk, so put
922 * the chunk back on the output queue.
924 SCTP_DEBUG_PRINTK("sctp_outq_flush: could "
925 "not transmit TSN: 0x%x, status: %d\n",
926 ntohl(chunk
->subh
.data_hdr
->tsn
),
928 sctp_outq_head_data(q
, chunk
);
939 /* BUG: We assume that the sctp_packet_transmit()
940 * call below will succeed all the time and add the
941 * chunk to the transmitted list and restart the
943 * It is possible that the call can fail under OOM
946 * Is this really a problem? Won't this behave
949 list_add_tail(&chunk
->transmitted_list
,
950 &transport
->transmitted
);
952 sctp_transport_reset_timers(transport
);
956 /* Only let one DATA chunk get bundled with a
959 if (packet
->has_cookie_echo
)
971 /* Before returning, examine all the transports touched in
972 * this call. Right now, we bluntly force clear all the
973 * transports. Things might change after we implement Nagle.
974 * But such an examination is still required.
978 while ((ltransport
= sctp_list_dequeue(&transport_list
)) != NULL
) {
979 struct sctp_transport
*t
= list_entry(ltransport
,
980 struct sctp_transport
,
983 if (!sctp_packet_empty(packet
))
984 error
= sctp_packet_transmit(packet
);
990 /* Update unack_data based on the incoming SACK chunk */
991 static void sctp_sack_update_unack_data(struct sctp_association
*assoc
,
992 struct sctp_sackhdr
*sack
)
994 sctp_sack_variable_t
*frags
;
998 unack_data
= assoc
->next_tsn
- assoc
->ctsn_ack_point
- 1;
1000 frags
= sack
->variable
;
1001 for (i
= 0; i
< ntohs(sack
->num_gap_ack_blocks
); i
++) {
1002 unack_data
-= ((ntohs(frags
[i
].gab
.end
) -
1003 ntohs(frags
[i
].gab
.start
) + 1));
1006 assoc
->unack_data
= unack_data
;
1009 /* Return the highest new tsn that is acknowledged by the given SACK chunk. */
1010 static __u32
sctp_highest_new_tsn(struct sctp_sackhdr
*sack
,
1011 struct sctp_association
*asoc
)
1013 struct list_head
*ltransport
, *lchunk
;
1014 struct sctp_transport
*transport
;
1015 struct sctp_chunk
*chunk
;
1016 __u32 highest_new_tsn
, tsn
;
1017 struct list_head
*transport_list
= &asoc
->peer
.transport_addr_list
;
1019 highest_new_tsn
= ntohl(sack
->cum_tsn_ack
);
1021 list_for_each(ltransport
, transport_list
) {
1022 transport
= list_entry(ltransport
, struct sctp_transport
,
1024 list_for_each(lchunk
, &transport
->transmitted
) {
1025 chunk
= list_entry(lchunk
, struct sctp_chunk
,
1027 tsn
= ntohl(chunk
->subh
.data_hdr
->tsn
);
1029 if (!chunk
->tsn_gap_acked
&&
1030 TSN_lt(highest_new_tsn
, tsn
) &&
1031 sctp_acked(sack
, tsn
))
1032 highest_new_tsn
= tsn
;
1036 return highest_new_tsn
;
1039 /* This is where we REALLY process a SACK.
1041 * Process the SACK against the outqueue. Mostly, this just frees
1042 * things off the transmitted queue.
1044 int sctp_outq_sack(struct sctp_outq
*q
, struct sctp_sackhdr
*sack
)
1046 struct sctp_association
*asoc
= q
->asoc
;
1047 struct sctp_transport
*transport
;
1048 struct sctp_chunk
*tchunk
= NULL
;
1049 struct list_head
*lchunk
, *transport_list
, *pos
, *temp
;
1050 sctp_sack_variable_t
*frags
= sack
->variable
;
1051 __u32 sack_ctsn
, ctsn
, tsn
;
1052 __u32 highest_tsn
, highest_new_tsn
;
1054 unsigned outstanding
;
1055 struct sctp_transport
*primary
= asoc
->peer
.primary_path
;
1056 int count_of_newacks
= 0;
1058 /* Grab the association's destination address list. */
1059 transport_list
= &asoc
->peer
.transport_addr_list
;
1061 sack_ctsn
= ntohl(sack
->cum_tsn_ack
);
1064 * SFR-CACC algorithm:
1065 * On receipt of a SACK the sender SHOULD execute the
1066 * following statements.
1068 * 1) If the cumulative ack in the SACK passes next tsn_at_change
1069 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be
1070 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for
1073 if (TSN_lte(primary
->cacc
.next_tsn_at_change
, sack_ctsn
)) {
1074 primary
->cacc
.changeover_active
= 0;
1075 list_for_each(pos
, transport_list
) {
1076 transport
= list_entry(pos
, struct sctp_transport
,
1078 transport
->cacc
.cycling_changeover
= 0;
1083 * SFR-CACC algorithm:
1084 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE
1085 * is set the receiver of the SACK MUST take the following actions:
1087 * A) Initialize the cacc_saw_newack to 0 for all destination
1090 if (sack
->num_gap_ack_blocks
&&
1091 primary
->cacc
.changeover_active
) {
1092 list_for_each(pos
, transport_list
) {
1093 transport
= list_entry(pos
, struct sctp_transport
,
1095 transport
->cacc
.cacc_saw_newack
= 0;
1099 /* Get the highest TSN in the sack. */
1100 highest_tsn
= sack_ctsn
;
1101 if (sack
->num_gap_ack_blocks
)
1103 ntohs(frags
[ntohs(sack
->num_gap_ack_blocks
) - 1].gab
.end
);
1105 if (TSN_lt(asoc
->highest_sacked
, highest_tsn
)) {
1106 highest_new_tsn
= highest_tsn
;
1107 asoc
->highest_sacked
= highest_tsn
;
1109 highest_new_tsn
= sctp_highest_new_tsn(sack
, asoc
);
1112 /* Run through the retransmit queue. Credit bytes received
1113 * and free those chunks that we can.
1115 sctp_check_transmitted(q
, &q
->retransmit
, NULL
, sack
, highest_new_tsn
);
1116 sctp_mark_missing(q
, &q
->retransmit
, NULL
, highest_new_tsn
, 0);
1118 /* Run through the transmitted queue.
1119 * Credit bytes received and free those chunks which we can.
1121 * This is a MASSIVE candidate for optimization.
1123 list_for_each(pos
, transport_list
) {
1124 transport
= list_entry(pos
, struct sctp_transport
,
1126 sctp_check_transmitted(q
, &transport
->transmitted
,
1127 transport
, sack
, highest_new_tsn
);
1129 * SFR-CACC algorithm:
1130 * C) Let count_of_newacks be the number of
1131 * destinations for which cacc_saw_newack is set.
1133 if (transport
->cacc
.cacc_saw_newack
)
1134 count_of_newacks
++;
1137 list_for_each(pos
, transport_list
) {
1138 transport
= list_entry(pos
, struct sctp_transport
,
1140 sctp_mark_missing(q
, &transport
->transmitted
, transport
,
1141 highest_new_tsn
, count_of_newacks
);
1144 /* Move the Cumulative TSN Ack Point if appropriate. */
1145 if (TSN_lt(asoc
->ctsn_ack_point
, sack_ctsn
))
1146 asoc
->ctsn_ack_point
= sack_ctsn
;
1148 /* Update unack_data field in the assoc. */
1149 sctp_sack_update_unack_data(asoc
, sack
);
1151 ctsn
= asoc
->ctsn_ack_point
;
1153 /* Throw away stuff rotting on the sack queue. */
1154 list_for_each_safe(lchunk
, temp
, &q
->sacked
) {
1155 tchunk
= list_entry(lchunk
, struct sctp_chunk
,
1157 tsn
= ntohl(tchunk
->subh
.data_hdr
->tsn
);
1158 if (TSN_lte(tsn
, ctsn
))
1159 sctp_chunk_free(tchunk
);
1162 /* ii) Set rwnd equal to the newly received a_rwnd minus the
1163 * number of bytes still outstanding after processing the
1164 * Cumulative TSN Ack and the Gap Ack Blocks.
1167 sack_a_rwnd
= ntohl(sack
->a_rwnd
);
1168 outstanding
= q
->outstanding_bytes
;
1170 if (outstanding
< sack_a_rwnd
)
1171 sack_a_rwnd
-= outstanding
;
1175 asoc
->peer
.rwnd
= sack_a_rwnd
;
1177 sctp_generate_fwdtsn(q
, sack_ctsn
);
1179 SCTP_DEBUG_PRINTK("%s: sack Cumulative TSN Ack is 0x%x.\n",
1180 __FUNCTION__
, sack_ctsn
);
1181 SCTP_DEBUG_PRINTK("%s: Cumulative TSN Ack of association, "
1182 "%p is 0x%x. Adv peer ack point: 0x%x\n",
1183 __FUNCTION__
, asoc
, ctsn
, asoc
->adv_peer_ack_point
);
1185 /* See if all chunks are acked.
1186 * Make sure the empty queue handler will get run later.
1188 q
->empty
= (list_empty(&q
->out_chunk_list
) &&
1189 list_empty(&q
->control_chunk_list
) &&
1190 list_empty(&q
->retransmit
));
1194 list_for_each(pos
, transport_list
) {
1195 transport
= list_entry(pos
, struct sctp_transport
,
1197 q
->empty
= q
->empty
&& list_empty(&transport
->transmitted
);
1202 SCTP_DEBUG_PRINTK("sack queue is empty.\n");
1207 /* Is the outqueue empty? */
1208 int sctp_outq_is_empty(const struct sctp_outq
*q
)
1213 /********************************************************************
1214 * 2nd Level Abstractions
1215 ********************************************************************/
1217 /* Go through a transport's transmitted list or the association's retransmit
1218 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked.
1219 * The retransmit list will not have an associated transport.
1221 * I added coherent debug information output. --xguo
1223 * Instead of printing 'sacked' or 'kept' for each TSN on the
1224 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5.
1225 * KEPT TSN6-TSN7, etc.
1227 static void sctp_check_transmitted(struct sctp_outq
*q
,
1228 struct list_head
*transmitted_queue
,
1229 struct sctp_transport
*transport
,
1230 struct sctp_sackhdr
*sack
,
1231 __u32 highest_new_tsn_in_sack
)
1233 struct list_head
*lchunk
;
1234 struct sctp_chunk
*tchunk
;
1235 struct list_head tlist
;
1239 __u8 restart_timer
= 0;
1240 int bytes_acked
= 0;
1242 /* These state variables are for coherent debug output. --xguo */
1245 __u32 dbg_ack_tsn
= 0; /* An ACKed TSN range starts here... */
1246 __u32 dbg_last_ack_tsn
= 0; /* ...and finishes here. */
1247 __u32 dbg_kept_tsn
= 0; /* An un-ACKed range starts here... */
1248 __u32 dbg_last_kept_tsn
= 0; /* ...and finishes here. */
1250 /* 0 : The last TSN was ACKed.
1251 * 1 : The last TSN was NOT ACKed (i.e. KEPT).
1252 * -1: We need to initialize.
1254 int dbg_prt_state
= -1;
1255 #endif /* SCTP_DEBUG */
1257 sack_ctsn
= ntohl(sack
->cum_tsn_ack
);
1259 INIT_LIST_HEAD(&tlist
);
1261 /* The while loop will skip empty transmitted queues. */
1262 while (NULL
!= (lchunk
= sctp_list_dequeue(transmitted_queue
))) {
1263 tchunk
= list_entry(lchunk
, struct sctp_chunk
,
1266 if (sctp_chunk_abandoned(tchunk
)) {
1267 /* Move the chunk to abandoned list. */
1268 sctp_insert_list(&q
->abandoned
, lchunk
);
1270 /* If this chunk has not been acked, stop
1271 * considering it as 'outstanding'.
1273 if (!tchunk
->tsn_gap_acked
) {
1274 tchunk
->transport
->flight_size
-=
1275 sctp_data_size(tchunk
);
1276 q
->outstanding_bytes
-= sctp_data_size(tchunk
);
1281 tsn
= ntohl(tchunk
->subh
.data_hdr
->tsn
);
1282 if (sctp_acked(sack
, tsn
)) {
1283 /* If this queue is the retransmit queue, the
1284 * retransmit timer has already reclaimed
1285 * the outstanding bytes for this chunk, so only
1286 * count bytes associated with a transport.
1289 /* If this chunk is being used for RTT
1290 * measurement, calculate the RTT and update
1291 * the RTO using this value.
1293 * 6.3.1 C5) Karn's algorithm: RTT measurements
1294 * MUST NOT be made using packets that were
1295 * retransmitted (and thus for which it is
1296 * ambiguous whether the reply was for the
1297 * first instance of the packet or a later
1300 if (!tchunk
->tsn_gap_acked
&&
1302 tchunk
->rtt_in_progress
) {
1303 tchunk
->rtt_in_progress
= 0;
1304 rtt
= jiffies
- tchunk
->sent_at
;
1305 sctp_transport_update_rto(transport
,
1309 if (TSN_lte(tsn
, sack_ctsn
)) {
1310 /* RFC 2960 6.3.2 Retransmission Timer Rules
1312 * R3) Whenever a SACK is received
1313 * that acknowledges the DATA chunk
1314 * with the earliest outstanding TSN
1315 * for that address, restart T3-rtx
1316 * timer for that address with its
1321 if (!tchunk
->tsn_gap_acked
) {
1322 tchunk
->tsn_gap_acked
= 1;
1323 bytes_acked
+= sctp_data_size(tchunk
);
1325 * SFR-CACC algorithm:
1326 * 2) If the SACK contains gap acks
1327 * and the flag CHANGEOVER_ACTIVE is
1328 * set the receiver of the SACK MUST
1329 * take the following action:
1331 * B) For each TSN t being acked that
1332 * has not been acked in any SACK so
1333 * far, set cacc_saw_newack to 1 for
1334 * the destination that the TSN was
1338 sack
->num_gap_ack_blocks
&&
1339 q
->asoc
->peer
.primary_path
->cacc
.
1341 transport
->cacc
.cacc_saw_newack
1345 list_add_tail(&tchunk
->transmitted_list
,
1348 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2
1349 * M2) Each time a SACK arrives reporting
1350 * 'Stray DATA chunk(s)' record the highest TSN
1351 * reported as newly acknowledged, call this
1352 * value 'HighestTSNinSack'. A newly
1353 * acknowledged DATA chunk is one not
1354 * previously acknowledged in a SACK.
1356 * When the SCTP sender of data receives a SACK
1357 * chunk that acknowledges, for the first time,
1358 * the receipt of a DATA chunk, all the still
1359 * unacknowledged DATA chunks whose TSN is
1360 * older than that newly acknowledged DATA
1361 * chunk, are qualified as 'Stray DATA chunks'.
1363 if (!tchunk
->tsn_gap_acked
) {
1364 tchunk
->tsn_gap_acked
= 1;
1365 bytes_acked
+= sctp_data_size(tchunk
);
1367 list_add_tail(lchunk
, &tlist
);
1371 switch (dbg_prt_state
) {
1372 case 0: /* last TSN was ACKed */
1373 if (dbg_last_ack_tsn
+ 1 == tsn
) {
1374 /* This TSN belongs to the
1375 * current ACK range.
1380 if (dbg_last_ack_tsn
!= dbg_ack_tsn
) {
1381 /* Display the end of the
1384 SCTP_DEBUG_PRINTK("-%08x",
1388 /* Start a new range. */
1389 SCTP_DEBUG_PRINTK(",%08x", tsn
);
1393 case 1: /* The last TSN was NOT ACKed. */
1394 if (dbg_last_kept_tsn
!= dbg_kept_tsn
) {
1395 /* Display the end of current range. */
1396 SCTP_DEBUG_PRINTK("-%08x",
1400 SCTP_DEBUG_PRINTK("\n");
1402 /* FALL THROUGH... */
1404 /* This is the first-ever TSN we examined. */
1405 /* Start a new range of ACK-ed TSNs. */
1406 SCTP_DEBUG_PRINTK("ACKed: %08x", tsn
);
1411 dbg_last_ack_tsn
= tsn
;
1412 #endif /* SCTP_DEBUG */
1415 if (tchunk
->tsn_gap_acked
) {
1416 SCTP_DEBUG_PRINTK("%s: Receiver reneged on "
1420 tchunk
->tsn_gap_acked
= 0;
1422 bytes_acked
-= sctp_data_size(tchunk
);
1424 /* RFC 2960 6.3.2 Retransmission Timer Rules
1426 * R4) Whenever a SACK is received missing a
1427 * TSN that was previously acknowledged via a
1428 * Gap Ack Block, start T3-rtx for the
1429 * destination address to which the DATA
1430 * chunk was originally
1431 * transmitted if it is not already running.
1436 list_add_tail(lchunk
, &tlist
);
1439 /* See the above comments on ACK-ed TSNs. */
1440 switch (dbg_prt_state
) {
1442 if (dbg_last_kept_tsn
+ 1 == tsn
)
1445 if (dbg_last_kept_tsn
!= dbg_kept_tsn
)
1446 SCTP_DEBUG_PRINTK("-%08x",
1449 SCTP_DEBUG_PRINTK(",%08x", tsn
);
1454 if (dbg_last_ack_tsn
!= dbg_ack_tsn
)
1455 SCTP_DEBUG_PRINTK("-%08x",
1457 SCTP_DEBUG_PRINTK("\n");
1459 /* FALL THROUGH... */
1461 SCTP_DEBUG_PRINTK("KEPT: %08x",tsn
);
1466 dbg_last_kept_tsn
= tsn
;
1467 #endif /* SCTP_DEBUG */
1472 /* Finish off the last range, displaying its ending TSN. */
1473 switch (dbg_prt_state
) {
1475 if (dbg_last_ack_tsn
!= dbg_ack_tsn
) {
1476 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_ack_tsn
);
1478 SCTP_DEBUG_PRINTK("\n");
1483 if (dbg_last_kept_tsn
!= dbg_kept_tsn
) {
1484 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_kept_tsn
);
1486 SCTP_DEBUG_PRINTK("\n");
1489 #endif /* SCTP_DEBUG */
1492 /* 8.2. When an outstanding TSN is acknowledged,
1493 * the endpoint shall clear the error counter of
1494 * the destination transport address to which the
1495 * DATA chunk was last sent.
1496 * The association's overall error counter is
1499 transport
->error_count
= 0;
1500 transport
->asoc
->overall_error_count
= 0;
1502 /* Mark the destination transport address as
1503 * active if it is not so marked.
1505 if ((transport
->state
== SCTP_INACTIVE
) ||
1506 (transport
->state
== SCTP_UNCONFIRMED
)) {
1507 sctp_assoc_control_transport(
1511 SCTP_RECEIVED_SACK
);
1514 sctp_transport_raise_cwnd(transport
, sack_ctsn
,
1517 transport
->flight_size
-= bytes_acked
;
1518 q
->outstanding_bytes
-= bytes_acked
;
1520 /* RFC 2960 6.1, sctpimpguide-06 2.15.2
1521 * When a sender is doing zero window probing, it
1522 * should not timeout the association if it continues
1523 * to receive new packets from the receiver. The
1524 * reason is that the receiver MAY keep its window
1525 * closed for an indefinite time.
1526 * A sender is doing zero window probing when the
1527 * receiver's advertised window is zero, and there is
1528 * only one data chunk in flight to the receiver.
1530 if (!q
->asoc
->peer
.rwnd
&&
1531 !list_empty(&tlist
) &&
1532 (sack_ctsn
+2 == q
->asoc
->next_tsn
)) {
1533 SCTP_DEBUG_PRINTK("%s: SACK received for zero "
1534 "window probe: %u\n",
1535 __FUNCTION__
, sack_ctsn
);
1536 q
->asoc
->overall_error_count
= 0;
1537 transport
->error_count
= 0;
1541 /* RFC 2960 6.3.2 Retransmission Timer Rules
1543 * R2) Whenever all outstanding data sent to an address have
1544 * been acknowledged, turn off the T3-rtx timer of that
1547 if (!transport
->flight_size
) {
1548 if (timer_pending(&transport
->T3_rtx_timer
) &&
1549 del_timer(&transport
->T3_rtx_timer
)) {
1550 sctp_transport_put(transport
);
1552 } else if (restart_timer
) {
1553 if (!mod_timer(&transport
->T3_rtx_timer
,
1554 jiffies
+ transport
->rto
))
1555 sctp_transport_hold(transport
);
1559 list_splice(&tlist
, transmitted_queue
);
1562 /* Mark chunks as missing and consequently may get retransmitted. */
1563 static void sctp_mark_missing(struct sctp_outq
*q
,
1564 struct list_head
*transmitted_queue
,
1565 struct sctp_transport
*transport
,
1566 __u32 highest_new_tsn_in_sack
,
1567 int count_of_newacks
)
1569 struct sctp_chunk
*chunk
;
1570 struct list_head
*pos
;
1572 char do_fast_retransmit
= 0;
1573 struct sctp_transport
*primary
= q
->asoc
->peer
.primary_path
;
1575 list_for_each(pos
, transmitted_queue
) {
1577 chunk
= list_entry(pos
, struct sctp_chunk
, transmitted_list
);
1578 tsn
= ntohl(chunk
->subh
.data_hdr
->tsn
);
1580 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all
1581 * 'Unacknowledged TSN's', if the TSN number of an
1582 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack'
1583 * value, increment the 'TSN.Missing.Report' count on that
1584 * chunk if it has NOT been fast retransmitted or marked for
1585 * fast retransmit already.
1587 if (!chunk
->fast_retransmit
&&
1588 !chunk
->tsn_gap_acked
&&
1589 TSN_lt(tsn
, highest_new_tsn_in_sack
)) {
1591 /* SFR-CACC may require us to skip marking
1592 * this chunk as missing.
1594 if (!transport
|| !sctp_cacc_skip(primary
, transport
,
1595 count_of_newacks
, tsn
)) {
1596 chunk
->tsn_missing_report
++;
1599 "%s: TSN 0x%x missing counter: %d\n",
1601 chunk
->tsn_missing_report
);
1605 * M4) If any DATA chunk is found to have a
1606 * 'TSN.Missing.Report'
1607 * value larger than or equal to 3, mark that chunk for
1608 * retransmission and start the fast retransmit procedure.
1611 if (chunk
->tsn_missing_report
>= 3) {
1612 chunk
->fast_retransmit
= 1;
1613 do_fast_retransmit
= 1;
1618 if (do_fast_retransmit
)
1619 sctp_retransmit(q
, transport
, SCTP_RTXR_FAST_RTX
);
1621 SCTP_DEBUG_PRINTK("%s: transport: %p, cwnd: %d, "
1622 "ssthresh: %d, flight_size: %d, pba: %d\n",
1623 __FUNCTION__
, transport
, transport
->cwnd
,
1624 transport
->ssthresh
, transport
->flight_size
,
1625 transport
->partial_bytes_acked
);
1629 /* Is the given TSN acked by this packet? */
1630 static int sctp_acked(struct sctp_sackhdr
*sack
, __u32 tsn
)
1633 sctp_sack_variable_t
*frags
;
1635 __u32 ctsn
= ntohl(sack
->cum_tsn_ack
);
1637 if (TSN_lte(tsn
, ctsn
))
1640 /* 3.3.4 Selective Acknowledgement (SACK) (3):
1643 * These fields contain the Gap Ack Blocks. They are repeated
1644 * for each Gap Ack Block up to the number of Gap Ack Blocks
1645 * defined in the Number of Gap Ack Blocks field. All DATA
1646 * chunks with TSNs greater than or equal to (Cumulative TSN
1647 * Ack + Gap Ack Block Start) and less than or equal to
1648 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack
1649 * Block are assumed to have been received correctly.
1652 frags
= sack
->variable
;
1654 for (i
= 0; i
< ntohs(sack
->num_gap_ack_blocks
); ++i
) {
1655 if (TSN_lte(ntohs(frags
[i
].gab
.start
), gap
) &&
1656 TSN_lte(gap
, ntohs(frags
[i
].gab
.end
)))
1665 static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip
*skiplist
,
1666 int nskips
, __be16 stream
)
1670 for (i
= 0; i
< nskips
; i
++) {
1671 if (skiplist
[i
].stream
== stream
)
1677 /* Create and add a fwdtsn chunk to the outq's control queue if needed. */
1678 static void sctp_generate_fwdtsn(struct sctp_outq
*q
, __u32 ctsn
)
1680 struct sctp_association
*asoc
= q
->asoc
;
1681 struct sctp_chunk
*ftsn_chunk
= NULL
;
1682 struct sctp_fwdtsn_skip ftsn_skip_arr
[10];
1686 struct sctp_chunk
*chunk
;
1687 struct list_head
*lchunk
, *temp
;
1689 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the
1692 * If (Advanced.Peer.Ack.Point < SackCumAck), then update
1693 * Advanced.Peer.Ack.Point to be equal to SackCumAck.
1695 if (TSN_lt(asoc
->adv_peer_ack_point
, ctsn
))
1696 asoc
->adv_peer_ack_point
= ctsn
;
1698 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point"
1699 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as
1700 * the chunk next in the out-queue space is marked as "abandoned" as
1701 * shown in the following example:
1703 * Assuming that a SACK arrived with the Cumulative TSN ACK 102
1704 * and the Advanced.Peer.Ack.Point is updated to this value:
1706 * out-queue at the end of ==> out-queue after Adv.Ack.Point
1707 * normal SACK processing local advancement
1709 * Adv.Ack.Pt-> 102 acked 102 acked
1710 * 103 abandoned 103 abandoned
1711 * 104 abandoned Adv.Ack.P-> 104 abandoned
1713 * 106 acked 106 acked
1716 * In this example, the data sender successfully advanced the
1717 * "Advanced.Peer.Ack.Point" from 102 to 104 locally.
1719 list_for_each_safe(lchunk
, temp
, &q
->abandoned
) {
1720 chunk
= list_entry(lchunk
, struct sctp_chunk
,
1722 tsn
= ntohl(chunk
->subh
.data_hdr
->tsn
);
1724 /* Remove any chunks in the abandoned queue that are acked by
1727 if (TSN_lte(tsn
, ctsn
)) {
1728 list_del_init(lchunk
);
1729 sctp_chunk_free(chunk
);
1731 if (TSN_lte(tsn
, asoc
->adv_peer_ack_point
+1)) {
1732 asoc
->adv_peer_ack_point
= tsn
;
1733 if (chunk
->chunk_hdr
->flags
&
1734 SCTP_DATA_UNORDERED
)
1736 skip_pos
= sctp_get_skip_pos(&ftsn_skip_arr
[0],
1738 chunk
->subh
.data_hdr
->stream
);
1739 ftsn_skip_arr
[skip_pos
].stream
=
1740 chunk
->subh
.data_hdr
->stream
;
1741 ftsn_skip_arr
[skip_pos
].ssn
=
1742 chunk
->subh
.data_hdr
->ssn
;
1743 if (skip_pos
== nskips
)
1752 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point"
1753 * is greater than the Cumulative TSN ACK carried in the received
1754 * SACK, the data sender MUST send the data receiver a FORWARD TSN
1755 * chunk containing the latest value of the
1756 * "Advanced.Peer.Ack.Point".
1758 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD
1759 * list each stream and sequence number in the forwarded TSN. This
1760 * information will enable the receiver to easily find any
1761 * stranded TSN's waiting on stream reorder queues. Each stream
1762 * SHOULD only be reported once; this means that if multiple
1763 * abandoned messages occur in the same stream then only the
1764 * highest abandoned stream sequence number is reported. If the
1765 * total size of the FORWARD TSN does NOT fit in a single MTU then
1766 * the sender of the FORWARD TSN SHOULD lower the
1767 * Advanced.Peer.Ack.Point to the last TSN that will fit in a
1770 if (asoc
->adv_peer_ack_point
> ctsn
)
1771 ftsn_chunk
= sctp_make_fwdtsn(asoc
, asoc
->adv_peer_ack_point
,
1772 nskips
, &ftsn_skip_arr
[0]);
1775 list_add_tail(&ftsn_chunk
->list
, &q
->control_chunk_list
);
1776 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS
);