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
,
385 __u8 fast_retransmit
)
387 struct list_head
*lchunk
, *ltemp
;
388 struct sctp_chunk
*chunk
;
390 /* Walk through the specified transmitted queue. */
391 list_for_each_safe(lchunk
, ltemp
, &transport
->transmitted
) {
392 chunk
= list_entry(lchunk
, struct sctp_chunk
,
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
);
402 /* If we are doing retransmission due to a fast retransmit,
403 * only the chunk's that are marked for fast retransmit
404 * should be added to the retransmit queue. If we are doing
405 * retransmission due to a timeout or pmtu discovery, only the
406 * chunks that are not yet acked should be added to the
409 if ((fast_retransmit
&& (chunk
->fast_retransmit
> 0)) ||
410 (!fast_retransmit
&& !chunk
->tsn_gap_acked
)) {
411 /* RFC 2960 6.2.1 Processing a Received SACK
413 * C) Any time a DATA chunk is marked for
414 * retransmission (via either T3-rtx timer expiration
415 * (Section 6.3.3) or via fast retransmit
416 * (Section 7.2.4)), add the data size of those
417 * chunks to the rwnd.
419 q
->asoc
->peer
.rwnd
+= sctp_data_size(chunk
);
420 q
->outstanding_bytes
-= sctp_data_size(chunk
);
421 transport
->flight_size
-= sctp_data_size(chunk
);
423 /* sctpimpguide-05 Section 2.8.2
424 * M5) If a T3-rtx timer expires, the
425 * 'TSN.Missing.Report' of all affected TSNs is set
428 chunk
->tsn_missing_report
= 0;
430 /* If a chunk that is being used for RTT measurement
431 * has to be retransmitted, we cannot use this chunk
432 * anymore for RTT measurements. Reset rto_pending so
433 * that a new RTT measurement is started when a new
434 * data chunk is sent.
436 if (chunk
->rtt_in_progress
) {
437 chunk
->rtt_in_progress
= 0;
438 transport
->rto_pending
= 0;
441 /* Move the chunk to the retransmit queue. The chunks
442 * on the retransmit queue are always kept in order.
444 list_del_init(lchunk
);
445 sctp_insert_list(&q
->retransmit
, lchunk
);
449 SCTP_DEBUG_PRINTK("%s: transport: %p, fast_retransmit: %d, "
450 "cwnd: %d, ssthresh: %d, flight_size: %d, "
451 "pba: %d\n", __FUNCTION__
,
452 transport
, fast_retransmit
,
453 transport
->cwnd
, transport
->ssthresh
,
454 transport
->flight_size
,
455 transport
->partial_bytes_acked
);
459 /* Mark all the eligible packets on a transport for retransmission and force
462 void sctp_retransmit(struct sctp_outq
*q
, struct sctp_transport
*transport
,
463 sctp_retransmit_reason_t reason
)
466 __u8 fast_retransmit
= 0;
469 case SCTP_RTXR_T3_RTX
:
470 SCTP_INC_STATS(SCTP_MIB_T3_RETRANSMITS
);
471 sctp_transport_lower_cwnd(transport
, SCTP_LOWER_CWND_T3_RTX
);
472 /* Update the retran path if the T3-rtx timer has expired for
473 * the current retran path.
475 if (transport
== transport
->asoc
->peer
.retran_path
)
476 sctp_assoc_update_retran_path(transport
->asoc
);
478 case SCTP_RTXR_FAST_RTX
:
479 SCTP_INC_STATS(SCTP_MIB_FAST_RETRANSMITS
);
480 sctp_transport_lower_cwnd(transport
, SCTP_LOWER_CWND_FAST_RTX
);
483 case SCTP_RTXR_PMTUD
:
484 SCTP_INC_STATS(SCTP_MIB_PMTUD_RETRANSMITS
);
490 sctp_retransmit_mark(q
, transport
, fast_retransmit
);
492 /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination,
493 * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by
494 * following the procedures outlined in C1 - C5.
496 sctp_generate_fwdtsn(q
, q
->asoc
->ctsn_ack_point
);
498 error
= sctp_outq_flush(q
, /* rtx_timeout */ 1);
501 q
->asoc
->base
.sk
->sk_err
= -error
;
505 * Transmit DATA chunks on the retransmit queue. Upon return from
506 * sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which
507 * need to be transmitted by the caller.
508 * We assume that pkt->transport has already been set.
510 * The return value is a normal kernel error return value.
512 static int sctp_outq_flush_rtx(struct sctp_outq
*q
, struct sctp_packet
*pkt
,
513 int rtx_timeout
, int *start_timer
)
515 struct list_head
*lqueue
;
516 struct list_head
*lchunk
, *lchunk1
;
517 struct sctp_transport
*transport
= pkt
->transport
;
519 struct sctp_chunk
*chunk
, *chunk1
;
520 struct sctp_association
*asoc
;
524 lqueue
= &q
->retransmit
;
526 /* RFC 2960 6.3.3 Handle T3-rtx Expiration
528 * E3) Determine how many of the earliest (i.e., lowest TSN)
529 * outstanding DATA chunks for the address for which the
530 * T3-rtx has expired will fit into a single packet, subject
531 * to the MTU constraint for the path corresponding to the
532 * destination transport address to which the retransmission
533 * is being sent (this may be different from the address for
534 * which the timer expires [see Section 6.4]). Call this value
535 * K. Bundle and retransmit those K DATA chunks in a single
536 * packet to the destination endpoint.
538 * [Just to be painfully clear, if we are retransmitting
539 * because a timeout just happened, we should send only ONE
540 * packet of retransmitted data.]
542 lchunk
= sctp_list_dequeue(lqueue
);
545 chunk
= list_entry(lchunk
, struct sctp_chunk
,
548 /* Make sure that Gap Acked TSNs are not retransmitted. A
549 * simple approach is just to move such TSNs out of the
550 * way and into a 'transmitted' queue and skip to the
553 if (chunk
->tsn_gap_acked
) {
554 list_add_tail(lchunk
, &transport
->transmitted
);
555 lchunk
= sctp_list_dequeue(lqueue
);
559 /* Attempt to append this chunk to the packet. */
560 status
= sctp_packet_append_chunk(pkt
, chunk
);
563 case SCTP_XMIT_PMTU_FULL
:
564 /* Send this packet. */
565 if ((error
= sctp_packet_transmit(pkt
)) == 0)
568 /* If we are retransmitting, we should only
569 * send a single packet.
572 list_add(lchunk
, lqueue
);
576 /* Bundle lchunk in the next round. */
579 case SCTP_XMIT_RWND_FULL
:
580 /* Send this packet. */
581 if ((error
= sctp_packet_transmit(pkt
)) == 0)
584 /* Stop sending DATA as there is no more room
587 list_add(lchunk
, lqueue
);
591 case SCTP_XMIT_NAGLE_DELAY
:
592 /* Send this packet. */
593 if ((error
= sctp_packet_transmit(pkt
)) == 0)
596 /* Stop sending DATA because of nagle delay. */
597 list_add(lchunk
, lqueue
);
602 /* The append was successful, so add this chunk to
603 * the transmitted list.
605 list_add_tail(lchunk
, &transport
->transmitted
);
607 /* Mark the chunk as ineligible for fast retransmit
608 * after it is retransmitted.
610 if (chunk
->fast_retransmit
> 0)
611 chunk
->fast_retransmit
= -1;
616 /* Retrieve a new chunk to bundle. */
617 lchunk
= sctp_list_dequeue(lqueue
);
621 /* If we are here due to a retransmit timeout or a fast
622 * retransmit and if there are any chunks left in the retransmit
623 * queue that could not fit in the PMTU sized packet, they need * to be marked as ineligible for a subsequent fast retransmit.
625 if (rtx_timeout
&& !lchunk
) {
626 list_for_each(lchunk1
, lqueue
) {
627 chunk1
= list_entry(lchunk1
, struct sctp_chunk
,
629 if (chunk1
->fast_retransmit
> 0)
630 chunk1
->fast_retransmit
= -1;
638 /* Cork the outqueue so queued chunks are really queued. */
639 int sctp_outq_uncork(struct sctp_outq
*q
)
644 error
= sctp_outq_flush(q
, 0);
650 * Try to flush an outqueue.
652 * Description: Send everything in q which we legally can, subject to
653 * congestion limitations.
654 * * Note: This function can be called from multiple contexts so appropriate
655 * locking concerns must be made. Today we use the sock lock to protect
658 int sctp_outq_flush(struct sctp_outq
*q
, int rtx_timeout
)
660 struct sctp_packet
*packet
;
661 struct sctp_packet singleton
;
662 struct sctp_association
*asoc
= q
->asoc
;
663 __u16 sport
= asoc
->base
.bind_addr
.port
;
664 __u16 dport
= asoc
->peer
.port
;
665 __u32 vtag
= asoc
->peer
.i
.init_tag
;
666 struct sctp_transport
*transport
= NULL
;
667 struct sctp_transport
*new_transport
;
668 struct sctp_chunk
*chunk
, *tmp
;
673 /* These transports have chunks to send. */
674 struct list_head transport_list
;
675 struct list_head
*ltransport
;
677 INIT_LIST_HEAD(&transport_list
);
683 * When bundling control chunks with DATA chunks, an
684 * endpoint MUST place control chunks first in the outbound
685 * SCTP packet. The transmitter MUST transmit DATA chunks
686 * within a SCTP packet in increasing order of TSN.
690 list_for_each_entry_safe(chunk
, tmp
, &q
->control_chunk_list
, list
) {
691 list_del_init(&chunk
->list
);
693 /* Pick the right transport to use. */
694 new_transport
= chunk
->transport
;
696 if (!new_transport
) {
697 new_transport
= asoc
->peer
.active_path
;
698 } else if ((new_transport
->state
== SCTP_INACTIVE
) ||
699 (new_transport
->state
== SCTP_UNCONFIRMED
)) {
700 /* If the chunk is Heartbeat or Heartbeat Ack,
701 * send it to chunk->transport, even if it's
704 * 3.3.6 Heartbeat Acknowledgement:
706 * A HEARTBEAT ACK is always sent to the source IP
707 * address of the IP datagram containing the
708 * HEARTBEAT chunk to which this ack is responding.
711 if (chunk
->chunk_hdr
->type
!= SCTP_CID_HEARTBEAT
&&
712 chunk
->chunk_hdr
->type
!= SCTP_CID_HEARTBEAT_ACK
)
713 new_transport
= asoc
->peer
.active_path
;
716 /* Are we switching transports?
717 * Take care of transport locks.
719 if (new_transport
!= transport
) {
720 transport
= new_transport
;
721 if (list_empty(&transport
->send_ready
)) {
722 list_add_tail(&transport
->send_ready
,
725 packet
= &transport
->packet
;
726 sctp_packet_config(packet
, vtag
,
727 asoc
->peer
.ecn_capable
);
730 switch (chunk
->chunk_hdr
->type
) {
734 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN
735 * COMPLETE with any other chunks. [Send them immediately.]
738 case SCTP_CID_INIT_ACK
:
739 case SCTP_CID_SHUTDOWN_COMPLETE
:
740 sctp_packet_init(&singleton
, transport
, sport
, dport
);
741 sctp_packet_config(&singleton
, vtag
, 0);
742 sctp_packet_append_chunk(&singleton
, chunk
);
743 error
= sctp_packet_transmit(&singleton
);
750 case SCTP_CID_HEARTBEAT
:
751 case SCTP_CID_HEARTBEAT_ACK
:
752 case SCTP_CID_SHUTDOWN
:
753 case SCTP_CID_SHUTDOWN_ACK
:
755 case SCTP_CID_COOKIE_ECHO
:
756 case SCTP_CID_COOKIE_ACK
:
757 case SCTP_CID_ECN_ECNE
:
758 case SCTP_CID_ECN_CWR
:
759 case SCTP_CID_ASCONF
:
760 case SCTP_CID_ASCONF_ACK
:
761 case SCTP_CID_FWD_TSN
:
762 sctp_packet_transmit_chunk(packet
, chunk
);
766 /* We built a chunk with an illegal type! */
771 /* Is it OK to send data chunks? */
772 switch (asoc
->state
) {
773 case SCTP_STATE_COOKIE_ECHOED
:
774 /* Only allow bundling when this packet has a COOKIE-ECHO
777 if (!packet
|| !packet
->has_cookie_echo
)
781 case SCTP_STATE_ESTABLISHED
:
782 case SCTP_STATE_SHUTDOWN_PENDING
:
783 case SCTP_STATE_SHUTDOWN_RECEIVED
:
785 * RFC 2960 6.1 Transmission of DATA Chunks
787 * C) When the time comes for the sender to transmit,
788 * before sending new DATA chunks, the sender MUST
789 * first transmit any outstanding DATA chunks which
790 * are marked for retransmission (limited by the
793 if (!list_empty(&q
->retransmit
)) {
794 if (transport
== asoc
->peer
.retran_path
)
797 /* Switch transports & prepare the packet. */
799 transport
= asoc
->peer
.retran_path
;
801 if (list_empty(&transport
->send_ready
)) {
802 list_add_tail(&transport
->send_ready
,
806 packet
= &transport
->packet
;
807 sctp_packet_config(packet
, vtag
,
808 asoc
->peer
.ecn_capable
);
810 error
= sctp_outq_flush_rtx(q
, packet
,
811 rtx_timeout
, &start_timer
);
814 sctp_transport_reset_timers(transport
);
816 /* This can happen on COOKIE-ECHO resend. Only
817 * one chunk can get bundled with a COOKIE-ECHO.
819 if (packet
->has_cookie_echo
)
822 /* Don't send new data if there is still data
823 * waiting to retransmit.
825 if (!list_empty(&q
->retransmit
))
829 /* Finally, transmit new packets. */
831 while ((chunk
= sctp_outq_dequeue_data(q
)) != NULL
) {
832 /* RFC 2960 6.5 Every DATA chunk MUST carry a valid
835 if (chunk
->sinfo
.sinfo_stream
>=
836 asoc
->c
.sinit_num_ostreams
) {
838 /* Mark as failed send. */
839 sctp_chunk_fail(chunk
, SCTP_ERROR_INV_STRM
);
840 sctp_chunk_free(chunk
);
844 /* Has this chunk expired? */
845 if (sctp_chunk_abandoned(chunk
)) {
846 sctp_chunk_fail(chunk
, 0);
847 sctp_chunk_free(chunk
);
851 /* If there is a specified transport, use it.
852 * Otherwise, we want to use the active path.
854 new_transport
= chunk
->transport
;
855 if (!new_transport
||
856 ((new_transport
->state
== SCTP_INACTIVE
) ||
857 (new_transport
->state
== SCTP_UNCONFIRMED
)))
858 new_transport
= asoc
->peer
.active_path
;
860 /* Change packets if necessary. */
861 if (new_transport
!= transport
) {
862 transport
= new_transport
;
864 /* Schedule to have this transport's
867 if (list_empty(&transport
->send_ready
)) {
868 list_add_tail(&transport
->send_ready
,
872 packet
= &transport
->packet
;
873 sctp_packet_config(packet
, vtag
,
874 asoc
->peer
.ecn_capable
);
877 SCTP_DEBUG_PRINTK("sctp_outq_flush(%p, %p[%s]), ",
879 chunk
&& chunk
->chunk_hdr
?
880 sctp_cname(SCTP_ST_CHUNK(
881 chunk
->chunk_hdr
->type
))
884 SCTP_DEBUG_PRINTK("TX TSN 0x%x skb->head "
885 "%p skb->users %d.\n",
886 ntohl(chunk
->subh
.data_hdr
->tsn
),
887 chunk
->skb
?chunk
->skb
->head
: NULL
,
889 atomic_read(&chunk
->skb
->users
) : -1);
891 /* Add the chunk to the packet. */
892 status
= sctp_packet_transmit_chunk(packet
, chunk
);
895 case SCTP_XMIT_PMTU_FULL
:
896 case SCTP_XMIT_RWND_FULL
:
897 case SCTP_XMIT_NAGLE_DELAY
:
898 /* We could not append this chunk, so put
899 * the chunk back on the output queue.
901 SCTP_DEBUG_PRINTK("sctp_outq_flush: could "
902 "not transmit TSN: 0x%x, status: %d\n",
903 ntohl(chunk
->subh
.data_hdr
->tsn
),
905 sctp_outq_head_data(q
, chunk
);
916 /* BUG: We assume that the sctp_packet_transmit()
917 * call below will succeed all the time and add the
918 * chunk to the transmitted list and restart the
920 * It is possible that the call can fail under OOM
923 * Is this really a problem? Won't this behave
926 list_add_tail(&chunk
->transmitted_list
,
927 &transport
->transmitted
);
929 sctp_transport_reset_timers(transport
);
933 /* Only let one DATA chunk get bundled with a
936 if (packet
->has_cookie_echo
)
948 /* Before returning, examine all the transports touched in
949 * this call. Right now, we bluntly force clear all the
950 * transports. Things might change after we implement Nagle.
951 * But such an examination is still required.
955 while ((ltransport
= sctp_list_dequeue(&transport_list
)) != NULL
) {
956 struct sctp_transport
*t
= list_entry(ltransport
,
957 struct sctp_transport
,
960 if (!sctp_packet_empty(packet
))
961 error
= sctp_packet_transmit(packet
);
967 /* Update unack_data based on the incoming SACK chunk */
968 static void sctp_sack_update_unack_data(struct sctp_association
*assoc
,
969 struct sctp_sackhdr
*sack
)
971 sctp_sack_variable_t
*frags
;
975 unack_data
= assoc
->next_tsn
- assoc
->ctsn_ack_point
- 1;
977 frags
= sack
->variable
;
978 for (i
= 0; i
< ntohs(sack
->num_gap_ack_blocks
); i
++) {
979 unack_data
-= ((ntohs(frags
[i
].gab
.end
) -
980 ntohs(frags
[i
].gab
.start
) + 1));
983 assoc
->unack_data
= unack_data
;
986 /* Return the highest new tsn that is acknowledged by the given SACK chunk. */
987 static __u32
sctp_highest_new_tsn(struct sctp_sackhdr
*sack
,
988 struct sctp_association
*asoc
)
990 struct list_head
*ltransport
, *lchunk
;
991 struct sctp_transport
*transport
;
992 struct sctp_chunk
*chunk
;
993 __u32 highest_new_tsn
, tsn
;
994 struct list_head
*transport_list
= &asoc
->peer
.transport_addr_list
;
996 highest_new_tsn
= ntohl(sack
->cum_tsn_ack
);
998 list_for_each(ltransport
, transport_list
) {
999 transport
= list_entry(ltransport
, struct sctp_transport
,
1001 list_for_each(lchunk
, &transport
->transmitted
) {
1002 chunk
= list_entry(lchunk
, struct sctp_chunk
,
1004 tsn
= ntohl(chunk
->subh
.data_hdr
->tsn
);
1006 if (!chunk
->tsn_gap_acked
&&
1007 TSN_lt(highest_new_tsn
, tsn
) &&
1008 sctp_acked(sack
, tsn
))
1009 highest_new_tsn
= tsn
;
1013 return highest_new_tsn
;
1016 /* This is where we REALLY process a SACK.
1018 * Process the SACK against the outqueue. Mostly, this just frees
1019 * things off the transmitted queue.
1021 int sctp_outq_sack(struct sctp_outq
*q
, struct sctp_sackhdr
*sack
)
1023 struct sctp_association
*asoc
= q
->asoc
;
1024 struct sctp_transport
*transport
;
1025 struct sctp_chunk
*tchunk
= NULL
;
1026 struct list_head
*lchunk
, *transport_list
, *pos
, *temp
;
1027 sctp_sack_variable_t
*frags
= sack
->variable
;
1028 __u32 sack_ctsn
, ctsn
, tsn
;
1029 __u32 highest_tsn
, highest_new_tsn
;
1031 unsigned outstanding
;
1032 struct sctp_transport
*primary
= asoc
->peer
.primary_path
;
1033 int count_of_newacks
= 0;
1035 /* Grab the association's destination address list. */
1036 transport_list
= &asoc
->peer
.transport_addr_list
;
1038 sack_ctsn
= ntohl(sack
->cum_tsn_ack
);
1041 * SFR-CACC algorithm:
1042 * On receipt of a SACK the sender SHOULD execute the
1043 * following statements.
1045 * 1) If the cumulative ack in the SACK passes next tsn_at_change
1046 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be
1047 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for
1050 if (TSN_lte(primary
->cacc
.next_tsn_at_change
, sack_ctsn
)) {
1051 primary
->cacc
.changeover_active
= 0;
1052 list_for_each(pos
, transport_list
) {
1053 transport
= list_entry(pos
, struct sctp_transport
,
1055 transport
->cacc
.cycling_changeover
= 0;
1060 * SFR-CACC algorithm:
1061 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE
1062 * is set the receiver of the SACK MUST take the following actions:
1064 * A) Initialize the cacc_saw_newack to 0 for all destination
1067 if (sack
->num_gap_ack_blocks
> 0 &&
1068 primary
->cacc
.changeover_active
) {
1069 list_for_each(pos
, transport_list
) {
1070 transport
= list_entry(pos
, struct sctp_transport
,
1072 transport
->cacc
.cacc_saw_newack
= 0;
1076 /* Get the highest TSN in the sack. */
1077 highest_tsn
= sack_ctsn
;
1078 if (sack
->num_gap_ack_blocks
)
1080 ntohs(frags
[ntohs(sack
->num_gap_ack_blocks
) - 1].gab
.end
);
1082 if (TSN_lt(asoc
->highest_sacked
, highest_tsn
)) {
1083 highest_new_tsn
= highest_tsn
;
1084 asoc
->highest_sacked
= highest_tsn
;
1086 highest_new_tsn
= sctp_highest_new_tsn(sack
, asoc
);
1089 /* Run through the retransmit queue. Credit bytes received
1090 * and free those chunks that we can.
1092 sctp_check_transmitted(q
, &q
->retransmit
, NULL
, sack
, highest_new_tsn
);
1093 sctp_mark_missing(q
, &q
->retransmit
, NULL
, highest_new_tsn
, 0);
1095 /* Run through the transmitted queue.
1096 * Credit bytes received and free those chunks which we can.
1098 * This is a MASSIVE candidate for optimization.
1100 list_for_each(pos
, transport_list
) {
1101 transport
= list_entry(pos
, struct sctp_transport
,
1103 sctp_check_transmitted(q
, &transport
->transmitted
,
1104 transport
, sack
, highest_new_tsn
);
1106 * SFR-CACC algorithm:
1107 * C) Let count_of_newacks be the number of
1108 * destinations for which cacc_saw_newack is set.
1110 if (transport
->cacc
.cacc_saw_newack
)
1111 count_of_newacks
++;
1114 list_for_each(pos
, transport_list
) {
1115 transport
= list_entry(pos
, struct sctp_transport
,
1117 sctp_mark_missing(q
, &transport
->transmitted
, transport
,
1118 highest_new_tsn
, count_of_newacks
);
1121 /* Move the Cumulative TSN Ack Point if appropriate. */
1122 if (TSN_lt(asoc
->ctsn_ack_point
, sack_ctsn
))
1123 asoc
->ctsn_ack_point
= sack_ctsn
;
1125 /* Update unack_data field in the assoc. */
1126 sctp_sack_update_unack_data(asoc
, sack
);
1128 ctsn
= asoc
->ctsn_ack_point
;
1130 /* Throw away stuff rotting on the sack queue. */
1131 list_for_each_safe(lchunk
, temp
, &q
->sacked
) {
1132 tchunk
= list_entry(lchunk
, struct sctp_chunk
,
1134 tsn
= ntohl(tchunk
->subh
.data_hdr
->tsn
);
1135 if (TSN_lte(tsn
, ctsn
))
1136 sctp_chunk_free(tchunk
);
1139 /* ii) Set rwnd equal to the newly received a_rwnd minus the
1140 * number of bytes still outstanding after processing the
1141 * Cumulative TSN Ack and the Gap Ack Blocks.
1144 sack_a_rwnd
= ntohl(sack
->a_rwnd
);
1145 outstanding
= q
->outstanding_bytes
;
1147 if (outstanding
< sack_a_rwnd
)
1148 sack_a_rwnd
-= outstanding
;
1152 asoc
->peer
.rwnd
= sack_a_rwnd
;
1154 sctp_generate_fwdtsn(q
, sack_ctsn
);
1156 SCTP_DEBUG_PRINTK("%s: sack Cumulative TSN Ack is 0x%x.\n",
1157 __FUNCTION__
, sack_ctsn
);
1158 SCTP_DEBUG_PRINTK("%s: Cumulative TSN Ack of association, "
1159 "%p is 0x%x. Adv peer ack point: 0x%x\n",
1160 __FUNCTION__
, asoc
, ctsn
, asoc
->adv_peer_ack_point
);
1162 /* See if all chunks are acked.
1163 * Make sure the empty queue handler will get run later.
1165 q
->empty
= (list_empty(&q
->out_chunk_list
) &&
1166 list_empty(&q
->control_chunk_list
) &&
1167 list_empty(&q
->retransmit
));
1171 list_for_each(pos
, transport_list
) {
1172 transport
= list_entry(pos
, struct sctp_transport
,
1174 q
->empty
= q
->empty
&& list_empty(&transport
->transmitted
);
1179 SCTP_DEBUG_PRINTK("sack queue is empty.\n");
1184 /* Is the outqueue empty? */
1185 int sctp_outq_is_empty(const struct sctp_outq
*q
)
1190 /********************************************************************
1191 * 2nd Level Abstractions
1192 ********************************************************************/
1194 /* Go through a transport's transmitted list or the association's retransmit
1195 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked.
1196 * The retransmit list will not have an associated transport.
1198 * I added coherent debug information output. --xguo
1200 * Instead of printing 'sacked' or 'kept' for each TSN on the
1201 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5.
1202 * KEPT TSN6-TSN7, etc.
1204 static void sctp_check_transmitted(struct sctp_outq
*q
,
1205 struct list_head
*transmitted_queue
,
1206 struct sctp_transport
*transport
,
1207 struct sctp_sackhdr
*sack
,
1208 __u32 highest_new_tsn_in_sack
)
1210 struct list_head
*lchunk
;
1211 struct sctp_chunk
*tchunk
;
1212 struct list_head tlist
;
1216 __u8 restart_timer
= 0;
1217 int bytes_acked
= 0;
1219 /* These state variables are for coherent debug output. --xguo */
1222 __u32 dbg_ack_tsn
= 0; /* An ACKed TSN range starts here... */
1223 __u32 dbg_last_ack_tsn
= 0; /* ...and finishes here. */
1224 __u32 dbg_kept_tsn
= 0; /* An un-ACKed range starts here... */
1225 __u32 dbg_last_kept_tsn
= 0; /* ...and finishes here. */
1227 /* 0 : The last TSN was ACKed.
1228 * 1 : The last TSN was NOT ACKed (i.e. KEPT).
1229 * -1: We need to initialize.
1231 int dbg_prt_state
= -1;
1232 #endif /* SCTP_DEBUG */
1234 sack_ctsn
= ntohl(sack
->cum_tsn_ack
);
1236 INIT_LIST_HEAD(&tlist
);
1238 /* The while loop will skip empty transmitted queues. */
1239 while (NULL
!= (lchunk
= sctp_list_dequeue(transmitted_queue
))) {
1240 tchunk
= list_entry(lchunk
, struct sctp_chunk
,
1243 if (sctp_chunk_abandoned(tchunk
)) {
1244 /* Move the chunk to abandoned list. */
1245 sctp_insert_list(&q
->abandoned
, lchunk
);
1249 tsn
= ntohl(tchunk
->subh
.data_hdr
->tsn
);
1250 if (sctp_acked(sack
, tsn
)) {
1251 /* If this queue is the retransmit queue, the
1252 * retransmit timer has already reclaimed
1253 * the outstanding bytes for this chunk, so only
1254 * count bytes associated with a transport.
1257 /* If this chunk is being used for RTT
1258 * measurement, calculate the RTT and update
1259 * the RTO using this value.
1261 * 6.3.1 C5) Karn's algorithm: RTT measurements
1262 * MUST NOT be made using packets that were
1263 * retransmitted (and thus for which it is
1264 * ambiguous whether the reply was for the
1265 * first instance of the packet or a later
1268 if (!tchunk
->tsn_gap_acked
&&
1270 tchunk
->rtt_in_progress
) {
1271 tchunk
->rtt_in_progress
= 0;
1272 rtt
= jiffies
- tchunk
->sent_at
;
1273 sctp_transport_update_rto(transport
,
1277 if (TSN_lte(tsn
, sack_ctsn
)) {
1278 /* RFC 2960 6.3.2 Retransmission Timer Rules
1280 * R3) Whenever a SACK is received
1281 * that acknowledges the DATA chunk
1282 * with the earliest outstanding TSN
1283 * for that address, restart T3-rtx
1284 * timer for that address with its
1289 if (!tchunk
->tsn_gap_acked
) {
1290 tchunk
->tsn_gap_acked
= 1;
1291 bytes_acked
+= sctp_data_size(tchunk
);
1293 * SFR-CACC algorithm:
1294 * 2) If the SACK contains gap acks
1295 * and the flag CHANGEOVER_ACTIVE is
1296 * set the receiver of the SACK MUST
1297 * take the following action:
1299 * B) For each TSN t being acked that
1300 * has not been acked in any SACK so
1301 * far, set cacc_saw_newack to 1 for
1302 * the destination that the TSN was
1306 sack
->num_gap_ack_blocks
&&
1307 q
->asoc
->peer
.primary_path
->cacc
.
1309 transport
->cacc
.cacc_saw_newack
1313 list_add_tail(&tchunk
->transmitted_list
,
1316 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2
1317 * M2) Each time a SACK arrives reporting
1318 * 'Stray DATA chunk(s)' record the highest TSN
1319 * reported as newly acknowledged, call this
1320 * value 'HighestTSNinSack'. A newly
1321 * acknowledged DATA chunk is one not
1322 * previously acknowledged in a SACK.
1324 * When the SCTP sender of data receives a SACK
1325 * chunk that acknowledges, for the first time,
1326 * the receipt of a DATA chunk, all the still
1327 * unacknowledged DATA chunks whose TSN is
1328 * older than that newly acknowledged DATA
1329 * chunk, are qualified as 'Stray DATA chunks'.
1331 if (!tchunk
->tsn_gap_acked
) {
1332 tchunk
->tsn_gap_acked
= 1;
1333 bytes_acked
+= sctp_data_size(tchunk
);
1335 list_add_tail(lchunk
, &tlist
);
1339 switch (dbg_prt_state
) {
1340 case 0: /* last TSN was ACKed */
1341 if (dbg_last_ack_tsn
+ 1 == tsn
) {
1342 /* This TSN belongs to the
1343 * current ACK range.
1348 if (dbg_last_ack_tsn
!= dbg_ack_tsn
) {
1349 /* Display the end of the
1352 SCTP_DEBUG_PRINTK("-%08x",
1356 /* Start a new range. */
1357 SCTP_DEBUG_PRINTK(",%08x", tsn
);
1361 case 1: /* The last TSN was NOT ACKed. */
1362 if (dbg_last_kept_tsn
!= dbg_kept_tsn
) {
1363 /* Display the end of current range. */
1364 SCTP_DEBUG_PRINTK("-%08x",
1368 SCTP_DEBUG_PRINTK("\n");
1370 /* FALL THROUGH... */
1372 /* This is the first-ever TSN we examined. */
1373 /* Start a new range of ACK-ed TSNs. */
1374 SCTP_DEBUG_PRINTK("ACKed: %08x", tsn
);
1379 dbg_last_ack_tsn
= tsn
;
1380 #endif /* SCTP_DEBUG */
1383 if (tchunk
->tsn_gap_acked
) {
1384 SCTP_DEBUG_PRINTK("%s: Receiver reneged on "
1388 tchunk
->tsn_gap_acked
= 0;
1390 bytes_acked
-= sctp_data_size(tchunk
);
1392 /* RFC 2960 6.3.2 Retransmission Timer Rules
1394 * R4) Whenever a SACK is received missing a
1395 * TSN that was previously acknowledged via a
1396 * Gap Ack Block, start T3-rtx for the
1397 * destination address to which the DATA
1398 * chunk was originally
1399 * transmitted if it is not already running.
1404 list_add_tail(lchunk
, &tlist
);
1407 /* See the above comments on ACK-ed TSNs. */
1408 switch (dbg_prt_state
) {
1410 if (dbg_last_kept_tsn
+ 1 == tsn
)
1413 if (dbg_last_kept_tsn
!= dbg_kept_tsn
)
1414 SCTP_DEBUG_PRINTK("-%08x",
1417 SCTP_DEBUG_PRINTK(",%08x", tsn
);
1422 if (dbg_last_ack_tsn
!= dbg_ack_tsn
)
1423 SCTP_DEBUG_PRINTK("-%08x",
1425 SCTP_DEBUG_PRINTK("\n");
1427 /* FALL THROUGH... */
1429 SCTP_DEBUG_PRINTK("KEPT: %08x",tsn
);
1434 dbg_last_kept_tsn
= tsn
;
1435 #endif /* SCTP_DEBUG */
1440 /* Finish off the last range, displaying its ending TSN. */
1441 switch (dbg_prt_state
) {
1443 if (dbg_last_ack_tsn
!= dbg_ack_tsn
) {
1444 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_ack_tsn
);
1446 SCTP_DEBUG_PRINTK("\n");
1451 if (dbg_last_kept_tsn
!= dbg_kept_tsn
) {
1452 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_kept_tsn
);
1454 SCTP_DEBUG_PRINTK("\n");
1457 #endif /* SCTP_DEBUG */
1460 /* 8.2. When an outstanding TSN is acknowledged,
1461 * the endpoint shall clear the error counter of
1462 * the destination transport address to which the
1463 * DATA chunk was last sent.
1464 * The association's overall error counter is
1467 transport
->error_count
= 0;
1468 transport
->asoc
->overall_error_count
= 0;
1470 /* Mark the destination transport address as
1471 * active if it is not so marked.
1473 if ((transport
->state
== SCTP_INACTIVE
) ||
1474 (transport
->state
== SCTP_UNCONFIRMED
)) {
1475 sctp_assoc_control_transport(
1479 SCTP_RECEIVED_SACK
);
1482 sctp_transport_raise_cwnd(transport
, sack_ctsn
,
1485 transport
->flight_size
-= bytes_acked
;
1486 q
->outstanding_bytes
-= bytes_acked
;
1488 /* RFC 2960 6.1, sctpimpguide-06 2.15.2
1489 * When a sender is doing zero window probing, it
1490 * should not timeout the association if it continues
1491 * to receive new packets from the receiver. The
1492 * reason is that the receiver MAY keep its window
1493 * closed for an indefinite time.
1494 * A sender is doing zero window probing when the
1495 * receiver's advertised window is zero, and there is
1496 * only one data chunk in flight to the receiver.
1498 if (!q
->asoc
->peer
.rwnd
&&
1499 !list_empty(&tlist
) &&
1500 (sack_ctsn
+2 == q
->asoc
->next_tsn
)) {
1501 SCTP_DEBUG_PRINTK("%s: SACK received for zero "
1502 "window probe: %u\n",
1503 __FUNCTION__
, sack_ctsn
);
1504 q
->asoc
->overall_error_count
= 0;
1505 transport
->error_count
= 0;
1509 /* RFC 2960 6.3.2 Retransmission Timer Rules
1511 * R2) Whenever all outstanding data sent to an address have
1512 * been acknowledged, turn off the T3-rtx timer of that
1515 if (!transport
->flight_size
) {
1516 if (timer_pending(&transport
->T3_rtx_timer
) &&
1517 del_timer(&transport
->T3_rtx_timer
)) {
1518 sctp_transport_put(transport
);
1520 } else if (restart_timer
) {
1521 if (!mod_timer(&transport
->T3_rtx_timer
,
1522 jiffies
+ transport
->rto
))
1523 sctp_transport_hold(transport
);
1527 list_splice(&tlist
, transmitted_queue
);
1530 /* Mark chunks as missing and consequently may get retransmitted. */
1531 static void sctp_mark_missing(struct sctp_outq
*q
,
1532 struct list_head
*transmitted_queue
,
1533 struct sctp_transport
*transport
,
1534 __u32 highest_new_tsn_in_sack
,
1535 int count_of_newacks
)
1537 struct sctp_chunk
*chunk
;
1538 struct list_head
*pos
;
1540 char do_fast_retransmit
= 0;
1541 struct sctp_transport
*primary
= q
->asoc
->peer
.primary_path
;
1543 list_for_each(pos
, transmitted_queue
) {
1545 chunk
= list_entry(pos
, struct sctp_chunk
, transmitted_list
);
1546 tsn
= ntohl(chunk
->subh
.data_hdr
->tsn
);
1548 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all
1549 * 'Unacknowledged TSN's', if the TSN number of an
1550 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack'
1551 * value, increment the 'TSN.Missing.Report' count on that
1552 * chunk if it has NOT been fast retransmitted or marked for
1553 * fast retransmit already.
1555 if (!chunk
->fast_retransmit
&&
1556 !chunk
->tsn_gap_acked
&&
1557 TSN_lt(tsn
, highest_new_tsn_in_sack
)) {
1559 /* SFR-CACC may require us to skip marking
1560 * this chunk as missing.
1562 if (!transport
|| !sctp_cacc_skip(primary
, transport
,
1563 count_of_newacks
, tsn
)) {
1564 chunk
->tsn_missing_report
++;
1567 "%s: TSN 0x%x missing counter: %d\n",
1569 chunk
->tsn_missing_report
);
1573 * M4) If any DATA chunk is found to have a
1574 * 'TSN.Missing.Report'
1575 * value larger than or equal to 3, mark that chunk for
1576 * retransmission and start the fast retransmit procedure.
1579 if (chunk
->tsn_missing_report
>= 3) {
1580 chunk
->fast_retransmit
= 1;
1581 do_fast_retransmit
= 1;
1586 if (do_fast_retransmit
)
1587 sctp_retransmit(q
, transport
, SCTP_RTXR_FAST_RTX
);
1589 SCTP_DEBUG_PRINTK("%s: transport: %p, cwnd: %d, "
1590 "ssthresh: %d, flight_size: %d, pba: %d\n",
1591 __FUNCTION__
, transport
, transport
->cwnd
,
1592 transport
->ssthresh
, transport
->flight_size
,
1593 transport
->partial_bytes_acked
);
1597 /* Is the given TSN acked by this packet? */
1598 static int sctp_acked(struct sctp_sackhdr
*sack
, __u32 tsn
)
1601 sctp_sack_variable_t
*frags
;
1603 __u32 ctsn
= ntohl(sack
->cum_tsn_ack
);
1605 if (TSN_lte(tsn
, ctsn
))
1608 /* 3.3.4 Selective Acknowledgement (SACK) (3):
1611 * These fields contain the Gap Ack Blocks. They are repeated
1612 * for each Gap Ack Block up to the number of Gap Ack Blocks
1613 * defined in the Number of Gap Ack Blocks field. All DATA
1614 * chunks with TSNs greater than or equal to (Cumulative TSN
1615 * Ack + Gap Ack Block Start) and less than or equal to
1616 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack
1617 * Block are assumed to have been received correctly.
1620 frags
= sack
->variable
;
1622 for (i
= 0; i
< ntohs(sack
->num_gap_ack_blocks
); ++i
) {
1623 if (TSN_lte(ntohs(frags
[i
].gab
.start
), gap
) &&
1624 TSN_lte(gap
, ntohs(frags
[i
].gab
.end
)))
1633 static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip
*skiplist
,
1634 int nskips
, __u16 stream
)
1638 for (i
= 0; i
< nskips
; i
++) {
1639 if (skiplist
[i
].stream
== stream
)
1645 /* Create and add a fwdtsn chunk to the outq's control queue if needed. */
1646 static void sctp_generate_fwdtsn(struct sctp_outq
*q
, __u32 ctsn
)
1648 struct sctp_association
*asoc
= q
->asoc
;
1649 struct sctp_chunk
*ftsn_chunk
= NULL
;
1650 struct sctp_fwdtsn_skip ftsn_skip_arr
[10];
1654 struct sctp_chunk
*chunk
;
1655 struct list_head
*lchunk
, *temp
;
1657 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the
1660 * If (Advanced.Peer.Ack.Point < SackCumAck), then update
1661 * Advanced.Peer.Ack.Point to be equal to SackCumAck.
1663 if (TSN_lt(asoc
->adv_peer_ack_point
, ctsn
))
1664 asoc
->adv_peer_ack_point
= ctsn
;
1666 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point"
1667 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as
1668 * the chunk next in the out-queue space is marked as "abandoned" as
1669 * shown in the following example:
1671 * Assuming that a SACK arrived with the Cumulative TSN ACK 102
1672 * and the Advanced.Peer.Ack.Point is updated to this value:
1674 * out-queue at the end of ==> out-queue after Adv.Ack.Point
1675 * normal SACK processing local advancement
1677 * Adv.Ack.Pt-> 102 acked 102 acked
1678 * 103 abandoned 103 abandoned
1679 * 104 abandoned Adv.Ack.P-> 104 abandoned
1681 * 106 acked 106 acked
1684 * In this example, the data sender successfully advanced the
1685 * "Advanced.Peer.Ack.Point" from 102 to 104 locally.
1687 list_for_each_safe(lchunk
, temp
, &q
->abandoned
) {
1688 chunk
= list_entry(lchunk
, struct sctp_chunk
,
1690 tsn
= ntohl(chunk
->subh
.data_hdr
->tsn
);
1692 /* Remove any chunks in the abandoned queue that are acked by
1695 if (TSN_lte(tsn
, ctsn
)) {
1696 list_del_init(lchunk
);
1697 if (!chunk
->tsn_gap_acked
) {
1698 chunk
->transport
->flight_size
-=
1699 sctp_data_size(chunk
);
1700 q
->outstanding_bytes
-= sctp_data_size(chunk
);
1702 sctp_chunk_free(chunk
);
1704 if (TSN_lte(tsn
, asoc
->adv_peer_ack_point
+1)) {
1705 asoc
->adv_peer_ack_point
= tsn
;
1706 if (chunk
->chunk_hdr
->flags
&
1707 SCTP_DATA_UNORDERED
)
1709 skip_pos
= sctp_get_skip_pos(&ftsn_skip_arr
[0],
1711 chunk
->subh
.data_hdr
->stream
);
1712 ftsn_skip_arr
[skip_pos
].stream
=
1713 chunk
->subh
.data_hdr
->stream
;
1714 ftsn_skip_arr
[skip_pos
].ssn
=
1715 chunk
->subh
.data_hdr
->ssn
;
1716 if (skip_pos
== nskips
)
1725 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point"
1726 * is greater than the Cumulative TSN ACK carried in the received
1727 * SACK, the data sender MUST send the data receiver a FORWARD TSN
1728 * chunk containing the latest value of the
1729 * "Advanced.Peer.Ack.Point".
1731 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD
1732 * list each stream and sequence number in the forwarded TSN. This
1733 * information will enable the receiver to easily find any
1734 * stranded TSN's waiting on stream reorder queues. Each stream
1735 * SHOULD only be reported once; this means that if multiple
1736 * abandoned messages occur in the same stream then only the
1737 * highest abandoned stream sequence number is reported. If the
1738 * total size of the FORWARD TSN does NOT fit in a single MTU then
1739 * the sender of the FORWARD TSN SHOULD lower the
1740 * Advanced.Peer.Ack.Point to the last TSN that will fit in a
1743 if (asoc
->adv_peer_ack_point
> ctsn
)
1744 ftsn_chunk
= sctp_make_fwdtsn(asoc
, asoc
->adv_peer_ack_point
,
1745 nskips
, &ftsn_skip_arr
[0]);
1748 list_add_tail(&ftsn_chunk
->list
, &q
->control_chunk_list
);
1749 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS
);