1 /* SCTP kernel reference Implementation
2 * Copyright (c) 1999-2000 Cisco, Inc.
3 * Copyright (c) 1999-2001 Motorola, Inc.
4 * Copyright (c) 2001-2003 Intel Corp.
5 * Copyright (c) 2001-2003 International Business Machines 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>
57 /* Declare internal functions here. */
58 static int sctp_acked(struct sctp_sackhdr
*sack
, __u32 tsn
);
59 static void sctp_check_transmitted(struct sctp_outq
*q
,
60 struct list_head
*transmitted_queue
,
61 struct sctp_transport
*transport
,
62 struct sctp_sackhdr
*sack
,
63 __u32 highest_new_tsn
);
65 static void sctp_mark_missing(struct sctp_outq
*q
,
66 struct list_head
*transmitted_queue
,
67 struct sctp_transport
*transport
,
68 __u32 highest_new_tsn
,
69 int count_of_newacks
);
71 /* Add data to the front of the queue. */
72 static inline void sctp_outq_head_data(struct sctp_outq
*q
,
73 struct sctp_chunk
*ch
)
75 __skb_queue_head(&q
->out
, (struct sk_buff
*)ch
);
76 q
->out_qlen
+= ch
->skb
->len
;
80 /* Take data from the front of the queue. */
81 static inline struct sctp_chunk
*sctp_outq_dequeue_data(struct sctp_outq
*q
)
83 struct sctp_chunk
*ch
;
84 ch
= (struct sctp_chunk
*)__skb_dequeue(&q
->out
);
86 q
->out_qlen
-= ch
->skb
->len
;
89 /* Add data chunk to the end of the queue. */
90 static inline void sctp_outq_tail_data(struct sctp_outq
*q
,
91 struct sctp_chunk
*ch
)
93 __skb_queue_tail(&q
->out
, (struct sk_buff
*)ch
);
94 q
->out_qlen
+= ch
->skb
->len
;
98 /* Insert a chunk behind chunk 'pos'. */
99 static inline void sctp_outq_insert_data(struct sctp_outq
*q
,
100 struct sctp_chunk
*ch
,
101 struct sctp_chunk
*pos
)
103 __skb_insert((struct sk_buff
*)ch
, (struct sk_buff
*)pos
->prev
,
104 (struct sk_buff
*)pos
, pos
->list
);
105 q
->out_qlen
+= ch
->skb
->len
;
109 * SFR-CACC algorithm:
110 * D) If count_of_newacks is greater than or equal to 2
111 * and t was not sent to the current primary then the
112 * sender MUST NOT increment missing report count for t.
114 static inline int sctp_cacc_skip_3_1_d(struct sctp_transport
*primary
,
115 struct sctp_transport
*transport
,
116 int count_of_newacks
)
118 if (count_of_newacks
>=2 && transport
!= primary
)
124 * SFR-CACC algorithm:
125 * F) If count_of_newacks is less than 2, let d be the
126 * destination to which t was sent. If cacc_saw_newack
127 * is 0 for destination d, then the sender MUST NOT
128 * increment missing report count for t.
130 static inline int sctp_cacc_skip_3_1_f(struct sctp_transport
*transport
,
131 int count_of_newacks
)
133 if (count_of_newacks
< 2 && !transport
->cacc
.cacc_saw_newack
)
139 * SFR-CACC algorithm:
140 * 3.1) If CYCLING_CHANGEOVER is 0, the sender SHOULD
141 * execute steps C, D, F.
143 * C has been implemented in sctp_outq_sack
145 static inline int sctp_cacc_skip_3_1(struct sctp_transport
*primary
,
146 struct sctp_transport
*transport
,
147 int count_of_newacks
)
149 if (!primary
->cacc
.cycling_changeover
) {
150 if (sctp_cacc_skip_3_1_d(primary
, transport
, count_of_newacks
))
152 if (sctp_cacc_skip_3_1_f(transport
, count_of_newacks
));
160 * SFR-CACC algorithm:
161 * 3.2) Else if CYCLING_CHANGEOVER is 1, and t is less
162 * than next_tsn_at_change of the current primary, then
163 * the sender MUST NOT increment missing report count
166 static inline int sctp_cacc_skip_3_2(struct sctp_transport
*primary
, __u32 tsn
)
168 if (primary
->cacc
.cycling_changeover
&&
169 TSN_lt(tsn
, primary
->cacc
.next_tsn_at_change
))
175 * SFR-CACC algorithm:
176 * 3) If the missing report count for TSN t is to be
177 * incremented according to [RFC2960] and
178 * [SCTP_STEWART-2002], and CHANGEOVER_ACTIVE is set,
179 * then the sender MUST futher execute steps 3.1 and
180 * 3.2 to determine if the missing report count for
181 * TSN t SHOULD NOT be incremented.
183 * 3.3) If 3.1 and 3.2 do not dictate that the missing
184 * report count for t should not be incremented, then
185 * the sender SOULD increment missing report count for
186 * t (according to [RFC2960] and [SCTP_STEWART_2002]).
188 static inline int sctp_cacc_skip(struct sctp_transport
*primary
,
189 struct sctp_transport
*transport
,
190 int count_of_newacks
,
193 if (primary
->cacc
.changeover_active
&&
194 (sctp_cacc_skip_3_1(primary
, transport
, count_of_newacks
)
195 || sctp_cacc_skip_3_2(primary
, tsn
)))
200 /* Generate a new outqueue. */
201 struct sctp_outq
*sctp_outq_new(struct sctp_association
*asoc
)
205 q
= t_new(struct sctp_outq
, GFP_KERNEL
);
207 sctp_outq_init(asoc
, q
);
213 /* Initialize an existing sctp_outq. This does the boring stuff.
214 * You still need to define handlers if you really want to DO
215 * something with this structure...
217 void sctp_outq_init(struct sctp_association
*asoc
, struct sctp_outq
*q
)
220 skb_queue_head_init(&q
->out
);
221 skb_queue_head_init(&q
->control
);
222 INIT_LIST_HEAD(&q
->retransmit
);
223 INIT_LIST_HEAD(&q
->sacked
);
225 q
->init_output
= NULL
;
226 q
->config_output
= NULL
;
227 q
->append_output
= NULL
;
228 q
->build_output
= NULL
;
229 q
->force_output
= NULL
;
231 q
->outstanding_bytes
= 0;
239 /* Free the outqueue structure and any related pending chunks.
241 void sctp_outq_teardown(struct sctp_outq
*q
)
243 struct sctp_transport
*transport
;
244 struct list_head
*lchunk
, *pos
, *temp
;
245 struct sctp_chunk
*chunk
;
247 /* Throw away unacknowledged chunks. */
248 list_for_each(pos
, &q
->asoc
->peer
.transport_addr_list
) {
249 transport
= list_entry(pos
, struct sctp_transport
, transports
);
250 while ((lchunk
= sctp_list_dequeue(&transport
->transmitted
))) {
251 chunk
= list_entry(lchunk
, struct sctp_chunk
,
253 /* Mark as part of a failed message. */
254 sctp_datamsg_fail(chunk
, q
->error
);
255 sctp_chunk_free(chunk
);
259 /* Throw away chunks that have been gap ACKed. */
260 list_for_each_safe(lchunk
, temp
, &q
->sacked
) {
262 chunk
= list_entry(lchunk
, struct sctp_chunk
,
264 sctp_datamsg_fail(chunk
, q
->error
);
265 sctp_chunk_free(chunk
);
268 /* Throw away any chunks in the retransmit queue. */
269 list_for_each_safe(lchunk
, temp
, &q
->retransmit
) {
271 chunk
= list_entry(lchunk
, struct sctp_chunk
,
273 sctp_datamsg_fail(chunk
, q
->error
);
274 sctp_chunk_free(chunk
);
277 /* Throw away any leftover data chunks. */
278 while ((chunk
= sctp_outq_dequeue_data(q
))) {
280 /* Mark as send failure. */
281 sctp_datamsg_fail(chunk
, q
->error
);
282 sctp_chunk_free(chunk
);
287 /* Throw away any leftover control chunks. */
288 while ((chunk
= (struct sctp_chunk
*) skb_dequeue(&q
->control
)))
289 sctp_chunk_free(chunk
);
292 /* Free the outqueue structure and any related pending chunks. */
293 void sctp_outq_free(struct sctp_outq
*q
)
295 /* Throw away leftover chunks. */
296 sctp_outq_teardown(q
);
298 /* If we were kmalloc()'d, free the memory. */
303 /* Put a new chunk in an sctp_outq. */
304 int sctp_outq_tail(struct sctp_outq
*q
, struct sctp_chunk
*chunk
)
308 SCTP_DEBUG_PRINTK("sctp_outq_tail(%p, %p[%s])\n",
309 q
, chunk
, chunk
&& chunk
->chunk_hdr
?
310 sctp_cname(SCTP_ST_CHUNK(chunk
->chunk_hdr
->type
))
313 /* If it is data, queue it up, otherwise, send it
316 if (SCTP_CID_DATA
== chunk
->chunk_hdr
->type
) {
317 /* Is it OK to queue data chunks? */
318 /* From 9. Termination of Association
320 * When either endpoint performs a shutdown, the
321 * association on each peer will stop accepting new
322 * data from its user and only deliver data in queue
323 * at the time of sending or receiving the SHUTDOWN
326 switch (q
->asoc
->state
) {
327 case SCTP_STATE_EMPTY
:
328 case SCTP_STATE_CLOSED
:
329 case SCTP_STATE_SHUTDOWN_PENDING
:
330 case SCTP_STATE_SHUTDOWN_SENT
:
331 case SCTP_STATE_SHUTDOWN_RECEIVED
:
332 case SCTP_STATE_SHUTDOWN_ACK_SENT
:
333 /* Cannot send after transport endpoint shutdown */
338 SCTP_DEBUG_PRINTK("outqueueing (%p, %p[%s])\n",
339 q
, chunk
, chunk
&& chunk
->chunk_hdr
?
340 sctp_cname(SCTP_ST_CHUNK(chunk
->chunk_hdr
->type
))
343 sctp_outq_tail_data(q
, chunk
);
344 if (chunk
->chunk_hdr
->flags
& SCTP_DATA_UNORDERED
)
345 SCTP_INC_STATS(SctpOutUnorderChunks
);
347 SCTP_INC_STATS(SctpOutOrderChunks
);
352 __skb_queue_tail(&q
->control
, (struct sk_buff
*) chunk
);
353 SCTP_INC_STATS(SctpOutCtrlChunks
);
360 error
= sctp_outq_flush(q
, 0);
365 /* Insert a chunk into the retransmit queue. Chunks on the retransmit
366 * queue are kept in order, based on the TSNs.
368 void sctp_retransmit_insert(struct list_head
*tlchunk
, struct sctp_outq
*q
)
370 struct list_head
*rlchunk
;
371 struct sctp_chunk
*tchunk
, *rchunk
;
375 tchunk
= list_entry(tlchunk
, struct sctp_chunk
, transmitted_list
);
376 ttsn
= ntohl(tchunk
->subh
.data_hdr
->tsn
);
378 list_for_each(rlchunk
, &q
->retransmit
) {
379 rchunk
= list_entry(rlchunk
, struct sctp_chunk
,
381 rtsn
= ntohl(rchunk
->subh
.data_hdr
->tsn
);
382 if (TSN_lt(ttsn
, rtsn
)) {
383 list_add(tlchunk
, rlchunk
->prev
);
389 list_add_tail(tlchunk
, &q
->retransmit
);
393 /* Mark all the eligible packets on a transport for retransmission. */
394 void sctp_retransmit_mark(struct sctp_outq
*q
,
395 struct sctp_transport
*transport
,
396 __u8 fast_retransmit
)
398 struct list_head
*lchunk
, *ltemp
;
399 struct sctp_chunk
*chunk
;
401 /* Walk through the specified transmitted queue. */
402 list_for_each_safe(lchunk
, ltemp
, &transport
->transmitted
) {
403 chunk
= list_entry(lchunk
, struct sctp_chunk
,
406 /* If we are doing retransmission due to a fast retransmit,
407 * only the chunk's that are marked for fast retransmit
408 * should be added to the retransmit queue. If we are doing
409 * retransmission due to a timeout or pmtu discovery, only the
410 * chunks that are not yet acked should be added to the
413 if ((fast_retransmit
&& chunk
->fast_retransmit
) ||
414 (!fast_retransmit
&& !chunk
->tsn_gap_acked
)) {
415 /* RFC 2960 6.2.1 Processing a Received SACK
417 * C) Any time a DATA chunk is marked for
418 * retransmission (via either T3-rtx timer expiration
419 * (Section 6.3.3) or via fast retransmit
420 * (Section 7.2.4)), add the data size of those
421 * chunks to the rwnd.
423 q
->asoc
->peer
.rwnd
+= sctp_data_size(chunk
);
424 q
->outstanding_bytes
-= sctp_data_size(chunk
);
425 transport
->flight_size
-= sctp_data_size(chunk
);
427 /* sctpimpguide-05 Section 2.8.2
428 * M5) If a T3-rtx timer expires, the
429 * 'TSN.Missing.Report' of all affected TSNs is set
432 chunk
->tsn_missing_report
= 0;
434 /* If a chunk that is being used for RTT measurement
435 * has to be retransmitted, we cannot use this chunk
436 * anymore for RTT measurements. Reset rto_pending so
437 * that a new RTT measurement is started when a new
438 * data chunk is sent.
440 if (chunk
->rtt_in_progress
) {
441 chunk
->rtt_in_progress
= 0;
442 transport
->rto_pending
= 0;
445 /* Move the chunk to the retransmit queue. The chunks
446 * on the retransmit queue is always kept in order.
449 sctp_retransmit_insert(lchunk
, q
);
453 SCTP_DEBUG_PRINTK("%s: transport: %p, fast_retransmit: %d, "
454 "cwnd: %d, ssthresh: %d, flight_size: %d, "
455 "pba: %d\n", __FUNCTION__
,
456 transport
, fast_retransmit
,
457 transport
->cwnd
, transport
->ssthresh
,
458 transport
->flight_size
,
459 transport
->partial_bytes_acked
);
463 /* Mark all the eligible packets on a transport for retransmission and force
466 void sctp_retransmit(struct sctp_outq
*q
, struct sctp_transport
*transport
,
467 sctp_retransmit_reason_t reason
)
470 __u8 fast_retransmit
= 0;
473 case SCTP_RTXR_T3_RTX
:
474 sctp_transport_lower_cwnd(transport
, SCTP_LOWER_CWND_T3_RTX
);
475 /* Update the retran path if the T3-rtx timer has expired for
476 * the current retran path.
478 if (transport
== transport
->asoc
->peer
.retran_path
)
479 sctp_assoc_update_retran_path(transport
->asoc
);
481 case SCTP_RTXR_FAST_RTX
:
482 sctp_transport_lower_cwnd(transport
, SCTP_LOWER_CWND_FAST_RTX
);
485 case SCTP_RTXR_PMTUD
:
490 sctp_retransmit_mark(q
, transport
, fast_retransmit
);
492 error
= sctp_outq_flush(q
, /* rtx_timeout */ 1);
495 q
->asoc
->base
.sk
->sk_err
= -error
;
499 * Transmit DATA chunks on the retransmit queue. Upon return from
500 * sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which
501 * need to be transmitted by the caller.
502 * We assume that pkt->transport has already been set.
504 * The return value is a normal kernel error return value.
506 static int sctp_outq_flush_rtx(struct sctp_outq
*q
, struct sctp_packet
*pkt
,
507 int rtx_timeout
, int *start_timer
)
509 struct list_head
*lqueue
;
510 struct list_head
*lchunk
;
511 struct sctp_transport
*transport
= pkt
->transport
;
513 struct sctp_chunk
*chunk
;
514 struct sctp_association
*asoc
;
518 lqueue
= &q
->retransmit
;
520 /* RFC 2960 6.3.3 Handle T3-rtx Expiration
522 * E3) Determine how many of the earliest (i.e., lowest TSN)
523 * outstanding DATA chunks for the address for which the
524 * T3-rtx has expired will fit into a single packet, subject
525 * to the MTU constraint for the path corresponding to the
526 * destination transport address to which the retransmission
527 * is being sent (this may be different from the address for
528 * which the timer expires [see Section 6.4]). Call this value
529 * K. Bundle and retransmit those K DATA chunks in a single
530 * packet to the destination endpoint.
532 * [Just to be painfully clear, if we are retransmitting
533 * because a timeout just happened, we should send only ONE
534 * packet of retransmitted data.]
536 lchunk
= sctp_list_dequeue(lqueue
);
539 chunk
= list_entry(lchunk
, struct sctp_chunk
,
542 /* Make sure that Gap Acked TSNs are not retransmitted. A
543 * simple approach is just to move such TSNs out of the
544 * way and into a 'transmitted' queue and skip to the
547 if (chunk
->tsn_gap_acked
) {
548 list_add_tail(lchunk
, &transport
->transmitted
);
549 lchunk
= sctp_list_dequeue(lqueue
);
553 /* Attempt to append this chunk to the packet. */
554 status
= (*q
->append_output
)(pkt
, chunk
);
557 case SCTP_XMIT_PMTU_FULL
:
558 /* Send this packet. */
559 if ((error
= (*q
->force_output
)(pkt
)) == 0)
562 /* If we are retransmitting, we should only
563 * send a single packet.
566 list_add(lchunk
, lqueue
);
570 /* Bundle lchunk in the next round. */
573 case SCTP_XMIT_RWND_FULL
:
574 /* Send this packet. */
575 if ((error
= (*q
->force_output
)(pkt
)) == 0)
578 /* Stop sending DATA as there is no more room
581 list_add(lchunk
, lqueue
);
586 /* The append was successful, so add this chunk to
587 * the transmitted list.
589 list_add_tail(lchunk
, &transport
->transmitted
);
593 /* Retrieve a new chunk to bundle. */
594 lchunk
= sctp_list_dequeue(lqueue
);
602 /* Cork the outqueue so queued chunks are really queued. */
603 int sctp_outq_uncork(struct sctp_outq
*q
)
608 error
= sctp_outq_flush(q
, 0);
614 * Try to flush an outqueue.
616 * Description: Send everything in q which we legally can, subject to
617 * congestion limitations.
618 * * Note: This function can be called from multiple contexts so appropriate
619 * locking concerns must be made. Today we use the sock lock to protect
622 int sctp_outq_flush(struct sctp_outq
*q
, int rtx_timeout
)
624 struct sctp_packet
*packet
;
625 struct sctp_packet singleton
;
626 struct sctp_association
*asoc
= q
->asoc
;
627 int ecn_capable
= asoc
->peer
.ecn_capable
;
628 __u16 sport
= asoc
->base
.bind_addr
.port
;
629 __u16 dport
= asoc
->peer
.port
;
630 __u32 vtag
= asoc
->peer
.i
.init_tag
;
631 /* This is the ECNE handler for singleton packets. */
632 sctp_packet_phandler_t
*s_ecne_handler
= NULL
;
633 sctp_packet_phandler_t
*ecne_handler
= NULL
;
634 struct sk_buff_head
*queue
;
635 struct sctp_transport
*transport
= NULL
;
636 struct sctp_transport
*new_transport
;
637 struct sctp_chunk
*chunk
;
642 /* These transports have chunks to send. */
643 struct list_head transport_list
;
644 struct list_head
*ltransport
;
646 INIT_LIST_HEAD(&transport_list
);
652 * When bundling control chunks with DATA chunks, an
653 * endpoint MUST place control chunks first in the outbound
654 * SCTP packet. The transmitter MUST transmit DATA chunks
655 * within a SCTP packet in increasing order of TSN.
659 s_ecne_handler
= &sctp_get_no_prepend
;
660 ecne_handler
= &sctp_get_ecne_prepend
;
664 while ((chunk
= (struct sctp_chunk
*)skb_dequeue(queue
))) {
665 /* Pick the right transport to use. */
666 new_transport
= chunk
->transport
;
668 if (!new_transport
) {
669 new_transport
= asoc
->peer
.active_path
;
670 } else if (!new_transport
->active
) {
671 /* If the chunk is Heartbeat, send it to
672 * chunk->transport, even it's inactive.
674 if (chunk
->chunk_hdr
->type
!= SCTP_CID_HEARTBEAT
)
675 new_transport
= asoc
->peer
.active_path
;
678 /* Are we switching transports?
679 * Take care of transport locks.
681 if (new_transport
!= transport
) {
682 transport
= new_transport
;
683 if (list_empty(&transport
->send_ready
)) {
684 list_add_tail(&transport
->send_ready
,
687 packet
= &transport
->packet
;
688 (*q
->config_output
)(packet
, vtag
,
689 ecn_capable
, ecne_handler
);
692 switch (chunk
->chunk_hdr
->type
) {
696 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN
697 * COMPLETE with any other chunks. [Send them immediately.]
700 case SCTP_CID_INIT_ACK
:
701 case SCTP_CID_SHUTDOWN_COMPLETE
:
702 (*q
->init_output
)(&singleton
, transport
, sport
, dport
);
703 (*q
->config_output
)(&singleton
, vtag
, ecn_capable
,
705 (void) (*q
->build_output
)(&singleton
, chunk
);
706 error
= (*q
->force_output
)(&singleton
);
713 case SCTP_CID_HEARTBEAT
:
714 case SCTP_CID_HEARTBEAT_ACK
:
715 case SCTP_CID_SHUTDOWN
:
716 case SCTP_CID_SHUTDOWN_ACK
:
718 case SCTP_CID_COOKIE_ECHO
:
719 case SCTP_CID_COOKIE_ACK
:
720 case SCTP_CID_ECN_ECNE
:
721 case SCTP_CID_ECN_CWR
:
722 (void) (*q
->build_output
)(packet
, chunk
);
725 case SCTP_CID_ASCONF
:
726 case SCTP_CID_ASCONF_ACK
:
727 (void) (*q
->build_output
)(packet
, chunk
);
731 /* We built a chunk with an illegal type! */
736 /* Is it OK to send data chunks? */
737 switch (asoc
->state
) {
738 case SCTP_STATE_COOKIE_ECHOED
:
739 /* Only allow bundling when this packet has a COOKIE-ECHO
742 if (!packet
|| !packet
->has_cookie_echo
)
746 case SCTP_STATE_ESTABLISHED
:
747 case SCTP_STATE_SHUTDOWN_PENDING
:
748 case SCTP_STATE_SHUTDOWN_RECEIVED
:
750 * RFC 2960 6.1 Transmission of DATA Chunks
752 * C) When the time comes for the sender to transmit,
753 * before sending new DATA chunks, the sender MUST
754 * first transmit any outstanding DATA chunks which
755 * are marked for retransmission (limited by the
758 if (!list_empty(&q
->retransmit
)) {
759 if (transport
== asoc
->peer
.retran_path
)
762 /* Switch transports & prepare the packet. */
764 transport
= asoc
->peer
.retran_path
;
766 if (list_empty(&transport
->send_ready
)) {
767 list_add_tail(&transport
->send_ready
,
771 packet
= &transport
->packet
;
772 (*q
->config_output
)(packet
, vtag
,
773 ecn_capable
, ecne_handler
);
775 error
= sctp_outq_flush_rtx(q
, packet
,
776 rtx_timeout
, &start_timer
);
779 sctp_transport_reset_timers(transport
);
781 /* This can happen on COOKIE-ECHO resend. Only
782 * one chunk can get bundled with a COOKIE-ECHO.
784 if (packet
->has_cookie_echo
)
787 /* Don't send new data if there is still data
788 * waiting to retransmit.
790 if (!list_empty(&q
->retransmit
))
794 /* Finally, transmit new packets. */
798 while ((chunk
= sctp_outq_dequeue_data(q
))) {
799 /* RFC 2960 6.5 Every DATA chunk MUST carry a valid
802 if (chunk
->sinfo
.sinfo_stream
>=
803 asoc
->c
.sinit_num_ostreams
) {
805 /* Mark as s failed send. */
806 sctp_datamsg_fail(chunk
, SCTP_ERROR_INV_STRM
);
807 sctp_chunk_free(chunk
);
811 /* Has this chunk expired? */
812 if (sctp_datamsg_expires(chunk
)) {
813 sctp_datamsg_fail(chunk
, 0);
814 sctp_chunk_free(chunk
);
818 /* If there is a specified transport, use it.
819 * Otherwise, we want to use the active path.
821 new_transport
= chunk
->transport
;
822 if (!new_transport
|| !new_transport
->active
)
823 new_transport
= asoc
->peer
.active_path
;
825 /* Change packets if necessary. */
826 if (new_transport
!= transport
) {
827 transport
= new_transport
;
829 /* Schedule to have this transport's
832 if (list_empty(&transport
->send_ready
)) {
833 list_add_tail(&transport
->send_ready
,
837 packet
= &transport
->packet
;
838 (*q
->config_output
)(packet
, vtag
,
839 ecn_capable
, ecne_handler
);
842 SCTP_DEBUG_PRINTK("sctp_transmit_packet(%p, %p[%s]), ",
844 chunk
&& chunk
->chunk_hdr
?
845 sctp_cname(SCTP_ST_CHUNK(
846 chunk
->chunk_hdr
->type
))
849 SCTP_DEBUG_PRINTK("TX TSN 0x%x skb->head "
850 "%p skb->users %d.\n",
851 ntohl(chunk
->subh
.data_hdr
->tsn
),
852 chunk
->skb
?chunk
->skb
->head
: 0,
854 atomic_read(&chunk
->skb
->users
) : -1);
856 /* Add the chunk to the packet. */
857 status
= (*q
->build_output
)(packet
, chunk
);
860 case SCTP_XMIT_PMTU_FULL
:
861 case SCTP_XMIT_RWND_FULL
:
862 case SCTP_XMIT_NAGLE_DELAY
:
863 /* We could not append this chunk, so put
864 * the chunk back on the output queue.
866 SCTP_DEBUG_PRINTK("sctp_outq_flush: could "
867 "not transmit TSN: 0x%x, status: %d\n",
868 ntohl(chunk
->subh
.data_hdr
->tsn
),
870 sctp_outq_head_data(q
, chunk
);
881 /* BUG: We assume that the (*q->force_output())
882 * call below will succeed all the time and add the
883 * chunk to the transmitted list and restart the
885 * It is possible that the call can fail under OOM
888 * Is this really a problem? Won't this behave
891 list_add_tail(&chunk
->transmitted_list
,
892 &transport
->transmitted
);
894 sctp_transport_reset_timers(transport
);
898 /* Only let one DATA chunk get bundled with a
901 if (packet
->has_cookie_echo
)
913 /* Before returning, examine all the transports touched in
914 * this call. Right now, we bluntly force clear all the
915 * transports. Things might change after we implement Nagle.
916 * But such an examination is still required.
920 while ((ltransport
= sctp_list_dequeue(&transport_list
)) != NULL
) {
921 struct sctp_transport
*t
= list_entry(ltransport
,
922 struct sctp_transport
,
927 packet
= &transport
->packet
;
928 if (packet
->size
!= SCTP_IP_OVERHEAD
)
929 error
= (*q
->force_output
)(packet
);
935 /* Set the various output handling callbacks. */
936 int sctp_outq_set_output_handlers(struct sctp_outq
*q
,
937 sctp_outq_ohandler_init_t init
,
938 sctp_outq_ohandler_config_t config
,
939 sctp_outq_ohandler_t append
,
940 sctp_outq_ohandler_t build
,
941 sctp_outq_ohandler_force_t force
)
943 q
->init_output
= init
;
944 q
->config_output
= config
;
945 q
->append_output
= append
;
946 q
->build_output
= build
;
947 q
->force_output
= force
;
951 /* Update unack_data based on the incoming SACK chunk */
952 static void sctp_sack_update_unack_data(struct sctp_association
*assoc
,
953 struct sctp_sackhdr
*sack
)
955 sctp_sack_variable_t
*frags
;
959 unack_data
= assoc
->next_tsn
- assoc
->ctsn_ack_point
- 1;
961 frags
= sack
->variable
;
962 for (i
= 0; i
< ntohs(sack
->num_gap_ack_blocks
); i
++) {
963 unack_data
-= ((ntohs(frags
[i
].gab
.end
) -
964 ntohs(frags
[i
].gab
.start
) + 1));
967 assoc
->unack_data
= unack_data
;
970 /* Return the highest new tsn that is acknowledged by the given SACK chunk. */
971 static __u32
sctp_highest_new_tsn(struct sctp_sackhdr
*sack
,
972 struct sctp_association
*asoc
)
974 struct list_head
*ltransport
, *lchunk
;
975 struct sctp_transport
*transport
;
976 struct sctp_chunk
*chunk
;
977 __u32 highest_new_tsn
, tsn
;
978 struct list_head
*transport_list
= &asoc
->peer
.transport_addr_list
;
980 highest_new_tsn
= ntohl(sack
->cum_tsn_ack
);
982 list_for_each(ltransport
, transport_list
) {
983 transport
= list_entry(ltransport
, struct sctp_transport
,
985 list_for_each(lchunk
, &transport
->transmitted
) {
986 chunk
= list_entry(lchunk
, struct sctp_chunk
,
988 tsn
= ntohl(chunk
->subh
.data_hdr
->tsn
);
990 if (!chunk
->tsn_gap_acked
&&
991 TSN_lt(highest_new_tsn
, tsn
) &&
992 sctp_acked(sack
, tsn
))
993 highest_new_tsn
= tsn
;
997 return highest_new_tsn
;
1000 /* This is where we REALLY process a SACK.
1002 * Process the SACK against the outqueue. Mostly, this just frees
1003 * things off the transmitted queue.
1005 int sctp_outq_sack(struct sctp_outq
*q
, struct sctp_sackhdr
*sack
)
1007 struct sctp_association
*asoc
= q
->asoc
;
1008 struct sctp_transport
*transport
;
1009 struct sctp_chunk
*tchunk
;
1010 struct list_head
*lchunk
, *transport_list
, *pos
;
1011 sctp_sack_variable_t
*frags
= sack
->variable
;
1012 __u32 sack_ctsn
, ctsn
, tsn
;
1013 __u32 highest_tsn
, highest_new_tsn
;
1015 unsigned outstanding
;
1016 struct sctp_transport
*primary
= asoc
->peer
.primary_path
;
1017 int count_of_newacks
= 0;
1019 /* Grab the association's destination address list. */
1020 transport_list
= &asoc
->peer
.transport_addr_list
;
1022 sack_ctsn
= ntohl(sack
->cum_tsn_ack
);
1025 * SFR-CACC algorithm:
1026 * On receipt of a SACK the sender SHOULD execute the
1027 * following statements.
1029 * 1) If the cumulative ack in the SACK passes next tsn_at_change
1030 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be
1031 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for
1034 if (TSN_lte(primary
->cacc
.next_tsn_at_change
, sack_ctsn
)) {
1035 primary
->cacc
.changeover_active
= 0;
1036 list_for_each(pos
, transport_list
) {
1037 transport
= list_entry(pos
, struct sctp_transport
,
1039 transport
->cacc
.cycling_changeover
= 0;
1044 * SFR-CACC algorithm:
1045 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE
1046 * is set the receiver of the SACK MUST take the following actions:
1048 * A) Initialize the cacc_saw_newack to 0 for all destination
1051 if (sack
->num_gap_ack_blocks
> 0 &&
1052 primary
->cacc
.changeover_active
) {
1053 list_for_each(pos
, transport_list
) {
1054 transport
= list_entry(pos
, struct sctp_transport
,
1056 transport
->cacc
.cacc_saw_newack
= 0;
1060 /* Get the highest TSN in the sack. */
1061 highest_tsn
= sack_ctsn
+
1062 ntohs(frags
[ntohs(sack
->num_gap_ack_blocks
) - 1].gab
.end
);
1064 if (TSN_lt(asoc
->highest_sacked
, highest_tsn
)) {
1065 highest_new_tsn
= highest_tsn
;
1066 asoc
->highest_sacked
= highest_tsn
;
1068 highest_new_tsn
= sctp_highest_new_tsn(sack
, asoc
);
1071 /* Run through the retransmit queue. Credit bytes received
1072 * and free those chunks that we can.
1074 sctp_check_transmitted(q
, &q
->retransmit
, NULL
, sack
, highest_new_tsn
);
1075 sctp_mark_missing(q
, &q
->retransmit
, NULL
, highest_new_tsn
, 0);
1077 /* Run through the transmitted queue.
1078 * Credit bytes received and free those chunks which we can.
1080 * This is a MASSIVE candidate for optimization.
1082 list_for_each(pos
, transport_list
) {
1083 transport
= list_entry(pos
, struct sctp_transport
,
1085 sctp_check_transmitted(q
, &transport
->transmitted
,
1086 transport
, sack
, highest_new_tsn
);
1088 * SFR-CACC algorithm:
1089 * C) Let count_of_newacks be the number of
1090 * destinations for which cacc_saw_newack is set.
1092 if (transport
->cacc
.cacc_saw_newack
)
1093 count_of_newacks
++;
1096 list_for_each(pos
, transport_list
) {
1097 transport
= list_entry(pos
, struct sctp_transport
,
1099 sctp_mark_missing(q
, &transport
->transmitted
, transport
,
1100 highest_new_tsn
, count_of_newacks
);
1103 /* Move the Cumulative TSN Ack Point if appropriate. */
1104 if (TSN_lt(asoc
->ctsn_ack_point
, sack_ctsn
))
1105 asoc
->ctsn_ack_point
= sack_ctsn
;
1107 /* Update unack_data field in the assoc. */
1108 sctp_sack_update_unack_data(asoc
, sack
);
1110 ctsn
= asoc
->ctsn_ack_point
;
1112 SCTP_DEBUG_PRINTK("%s: sack Cumulative TSN Ack is 0x%x.\n",
1113 __FUNCTION__
, sack_ctsn
);
1114 SCTP_DEBUG_PRINTK("%s: Cumulative TSN Ack of association "
1115 "%p is 0x%x.\n", __FUNCTION__
, asoc
, ctsn
);
1117 /* Throw away stuff rotting on the sack queue. */
1118 list_for_each(lchunk
, &q
->sacked
) {
1119 tchunk
= list_entry(lchunk
, struct sctp_chunk
,
1121 tsn
= ntohl(tchunk
->subh
.data_hdr
->tsn
);
1122 if (TSN_lte(tsn
, ctsn
)) {
1123 lchunk
= lchunk
->prev
;
1124 sctp_chunk_free(tchunk
);
1128 /* ii) Set rwnd equal to the newly received a_rwnd minus the
1129 * number of bytes still outstanding after processing the
1130 * Cumulative TSN Ack and the Gap Ack Blocks.
1133 sack_a_rwnd
= ntohl(sack
->a_rwnd
);
1134 outstanding
= q
->outstanding_bytes
;
1136 if (outstanding
< sack_a_rwnd
)
1137 sack_a_rwnd
-= outstanding
;
1141 asoc
->peer
.rwnd
= sack_a_rwnd
;
1143 /* See if all chunks are acked.
1144 * Make sure the empty queue handler will get run later.
1146 q
->empty
= skb_queue_empty(&q
->out
) && list_empty(&q
->retransmit
);
1150 list_for_each(pos
, transport_list
) {
1151 transport
= list_entry(pos
, struct sctp_transport
,
1153 q
->empty
= q
->empty
&& list_empty(&transport
->transmitted
);
1158 SCTP_DEBUG_PRINTK("sack queue is empty.\n");
1163 /* Is the outqueue empty? */
1164 int sctp_outq_is_empty(const struct sctp_outq
*q
)
1169 /********************************************************************
1170 * 2nd Level Abstractions
1171 ********************************************************************/
1173 /* Go through a transport's transmitted list or the association's retransmit
1174 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked.
1175 * The retransmit list will not have an associated transport.
1177 * I added coherent debug information output. --xguo
1179 * Instead of printing 'sacked' or 'kept' for each TSN on the
1180 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5.
1181 * KEPT TSN6-TSN7, etc.
1183 static void sctp_check_transmitted(struct sctp_outq
*q
,
1184 struct list_head
*transmitted_queue
,
1185 struct sctp_transport
*transport
,
1186 struct sctp_sackhdr
*sack
,
1187 __u32 highest_new_tsn_in_sack
)
1189 struct list_head
*lchunk
;
1190 struct sctp_chunk
*tchunk
;
1191 struct list_head tlist
;
1195 __u8 restart_timer
= 0;
1196 int bytes_acked
= 0;
1198 /* These state variables are for coherent debug output. --xguo */
1201 __u32 dbg_ack_tsn
= 0; /* An ACKed TSN range starts here... */
1202 __u32 dbg_last_ack_tsn
= 0; /* ...and finishes here. */
1203 __u32 dbg_kept_tsn
= 0; /* An un-ACKed range starts here... */
1204 __u32 dbg_last_kept_tsn
= 0; /* ...and finishes here. */
1206 /* 0 : The last TSN was ACKed.
1207 * 1 : The last TSN was NOT ACKed (i.e. KEPT).
1208 * -1: We need to initialize.
1210 int dbg_prt_state
= -1;
1211 #endif /* SCTP_DEBUG */
1213 sack_ctsn
= ntohl(sack
->cum_tsn_ack
);
1215 INIT_LIST_HEAD(&tlist
);
1217 /* The while loop will skip empty transmitted queues. */
1218 while (NULL
!= (lchunk
= sctp_list_dequeue(transmitted_queue
))) {
1219 tchunk
= list_entry(lchunk
, struct sctp_chunk
,
1222 tsn
= ntohl(tchunk
->subh
.data_hdr
->tsn
);
1223 if (sctp_acked(sack
, tsn
)) {
1224 /* If this queue is the retransmit queue, the
1225 * retransmit timer has already reclaimed
1226 * the outstanding bytes for this chunk, so only
1227 * count bytes associated with a transport.
1230 /* If this chunk is being used for RTT
1231 * measurement, calculate the RTT and update
1232 * the RTO using this value.
1234 * 6.3.1 C5) Karn's algorithm: RTT measurements
1235 * MUST NOT be made using packets that were
1236 * retransmitted (and thus for which it is
1237 * ambiguous whether the reply was for the
1238 * first instance of the packet or a later
1241 if (!tchunk
->tsn_gap_acked
&&
1243 tchunk
->rtt_in_progress
) {
1244 rtt
= jiffies
- tchunk
->sent_at
;
1245 sctp_transport_update_rto(transport
,
1249 if (TSN_lte(tsn
, sack_ctsn
)) {
1250 /* RFC 2960 6.3.2 Retransmission Timer Rules
1252 * R3) Whenever a SACK is received
1253 * that acknowledges the DATA chunk
1254 * with the earliest outstanding TSN
1255 * for that address, restart T3-rtx
1256 * timer for that address with its
1261 if (!tchunk
->tsn_gap_acked
) {
1262 tchunk
->tsn_gap_acked
= 1;
1263 bytes_acked
+= sctp_data_size(tchunk
);
1265 * SFR-CACC algorithm:
1266 * 2) If the SACK contains gap acks
1267 * and the flag CHANGEOVER_ACTIVE is
1268 * set the receiver of the SACK MUST
1269 * take the following action:
1271 * B) For each TSN t being acked that
1272 * has not been acked in any SACK so
1273 * far, set cacc_saw_newack to 1 for
1274 * the destination that the TSN was
1278 sack
->num_gap_ack_blocks
&&
1279 q
->asoc
->peer
.primary_path
->cacc
.
1281 transport
->cacc
.cacc_saw_newack
1285 list_add_tail(&tchunk
->transmitted_list
,
1288 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2
1289 * M2) Each time a SACK arrives reporting
1290 * 'Stray DATA chunk(s)' record the highest TSN
1291 * reported as newly acknowledged, call this
1292 * value 'HighestTSNinSack'. A newly
1293 * acknowledged DATA chunk is one not
1294 * previously acknowledged in a SACK.
1296 * When the SCTP sender of data receives a SACK
1297 * chunk that acknowledges, for the first time,
1298 * the receipt of a DATA chunk, all the still
1299 * unacknowledged DATA chunks whose TSN is
1300 * older than that newly acknowledged DATA
1301 * chunk, are qualified as 'Stray DATA chunks'.
1303 if (!tchunk
->tsn_gap_acked
) {
1304 tchunk
->tsn_gap_acked
= 1;
1305 bytes_acked
+= sctp_data_size(tchunk
);
1307 list_add_tail(lchunk
, &tlist
);
1311 switch (dbg_prt_state
) {
1312 case 0: /* last TSN was ACKed */
1313 if (dbg_last_ack_tsn
+ 1 == tsn
) {
1314 /* This TSN belongs to the
1315 * current ACK range.
1320 if (dbg_last_ack_tsn
!= dbg_ack_tsn
) {
1321 /* Display the end of the
1324 SCTP_DEBUG_PRINTK("-%08x",
1328 /* Start a new range. */
1329 SCTP_DEBUG_PRINTK(",%08x", tsn
);
1333 case 1: /* The last TSN was NOT ACKed. */
1334 if (dbg_last_kept_tsn
!= dbg_kept_tsn
) {
1335 /* Display the end of current range. */
1336 SCTP_DEBUG_PRINTK("-%08x",
1340 SCTP_DEBUG_PRINTK("\n");
1342 /* FALL THROUGH... */
1344 /* This is the first-ever TSN we examined. */
1345 /* Start a new range of ACK-ed TSNs. */
1346 SCTP_DEBUG_PRINTK("ACKed: %08x", tsn
);
1351 dbg_last_ack_tsn
= tsn
;
1352 #endif /* SCTP_DEBUG */
1355 if (tchunk
->tsn_gap_acked
) {
1356 SCTP_DEBUG_PRINTK("%s: Receiver reneged on "
1360 tchunk
->tsn_gap_acked
= 0;
1362 bytes_acked
-= sctp_data_size(tchunk
);
1364 /* RFC 2960 6.3.2 Retransmission Timer Rules
1366 * R4) Whenever a SACK is received missing a
1367 * TSN that was previously acknowledged via a
1368 * Gap Ack Block, start T3-rtx for the
1369 * destination address to which the DATA
1370 * chunk was originally
1371 * transmitted if it is not already running.
1376 list_add_tail(lchunk
, &tlist
);
1379 /* See the above comments on ACK-ed TSNs. */
1380 switch (dbg_prt_state
) {
1382 if (dbg_last_kept_tsn
+ 1 == tsn
)
1385 if (dbg_last_kept_tsn
!= dbg_kept_tsn
)
1386 SCTP_DEBUG_PRINTK("-%08x",
1389 SCTP_DEBUG_PRINTK(",%08x", tsn
);
1394 if (dbg_last_ack_tsn
!= dbg_ack_tsn
)
1395 SCTP_DEBUG_PRINTK("-%08x",
1397 SCTP_DEBUG_PRINTK("\n");
1399 /* FALL THROUGH... */
1401 SCTP_DEBUG_PRINTK("KEPT: %08x",tsn
);
1406 dbg_last_kept_tsn
= tsn
;
1407 #endif /* SCTP_DEBUG */
1412 /* Finish off the last range, displaying its ending TSN. */
1413 switch (dbg_prt_state
) {
1415 if (dbg_last_ack_tsn
!= dbg_ack_tsn
) {
1416 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_ack_tsn
);
1418 SCTP_DEBUG_PRINTK("\n");
1423 if (dbg_last_kept_tsn
!= dbg_kept_tsn
) {
1424 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_kept_tsn
);
1426 SCTP_DEBUG_PRINTK("\n");
1429 #endif /* SCTP_DEBUG */
1432 /* 8.2. When an outstanding TSN is acknowledged,
1433 * the endpoint shall clear the error counter of
1434 * the destination transport address to which the
1435 * DATA chunk was last sent.
1436 * The association's overall error counter is
1439 transport
->error_count
= 0;
1440 transport
->asoc
->overall_error_count
= 0;
1442 /* Mark the destination transport address as
1443 * active if it is not so marked.
1445 if (!transport
->active
) {
1446 sctp_assoc_control_transport(
1450 SCTP_RECEIVED_SACK
);
1453 sctp_transport_raise_cwnd(transport
, sack_ctsn
,
1456 transport
->flight_size
-= bytes_acked
;
1457 q
->outstanding_bytes
-= bytes_acked
;
1459 /* RFC 2960 6.1, sctpimpguide-06 2.15.2
1460 * When a sender is doing zero window probing, it
1461 * should not timeout the association if it continues
1462 * to receive new packets from the receiver. The
1463 * reason is that the receiver MAY keep its window
1464 * closed for an indefinite time.
1465 * A sender is doing zero window probing when the
1466 * receiver's advertised window is zero, and there is
1467 * only one data chunk in flight to the receiver.
1469 if (!q
->asoc
->peer
.rwnd
&&
1470 !list_empty(&tlist
) &&
1471 (sack_ctsn
+2 == q
->asoc
->next_tsn
)) {
1472 SCTP_DEBUG_PRINTK("%s: SACK received for zero "
1473 "window probe: %u\n",
1474 __FUNCTION__
, sack_ctsn
);
1475 q
->asoc
->overall_error_count
= 0;
1476 transport
->error_count
= 0;
1480 /* RFC 2960 6.3.2 Retransmission Timer Rules
1482 * R2) Whenever all outstanding data sent to an address have
1483 * been acknowledged, turn off the T3-rtx timer of that
1486 if (!transport
->flight_size
) {
1487 if (timer_pending(&transport
->T3_rtx_timer
) &&
1488 del_timer(&transport
->T3_rtx_timer
)) {
1489 sctp_transport_put(transport
);
1491 } else if (restart_timer
) {
1492 if (!mod_timer(&transport
->T3_rtx_timer
,
1493 jiffies
+ transport
->rto
))
1494 sctp_transport_hold(transport
);
1498 list_splice(&tlist
, transmitted_queue
);
1501 /* Mark chunks as missing and consequently may get retransmitted. */
1502 static void sctp_mark_missing(struct sctp_outq
*q
,
1503 struct list_head
*transmitted_queue
,
1504 struct sctp_transport
*transport
,
1505 __u32 highest_new_tsn_in_sack
,
1506 int count_of_newacks
)
1508 struct sctp_chunk
*chunk
;
1509 struct list_head
*pos
;
1511 char do_fast_retransmit
= 0;
1512 struct sctp_transport
*primary
= q
->asoc
->peer
.primary_path
;
1514 list_for_each(pos
, transmitted_queue
) {
1516 chunk
= list_entry(pos
, struct sctp_chunk
, transmitted_list
);
1517 tsn
= ntohl(chunk
->subh
.data_hdr
->tsn
);
1519 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all
1520 * 'Unacknowledged TSN's', if the TSN number of an
1521 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack'
1522 * value, increment the 'TSN.Missing.Report' count on that
1523 * chunk if it has NOT been fast retransmitted or marked for
1524 * fast retransmit already.
1526 if (!chunk
->fast_retransmit
&&
1527 !chunk
->tsn_gap_acked
&&
1528 TSN_lt(tsn
, highest_new_tsn_in_sack
)) {
1530 /* SFR-CACC may require us to skip marking
1531 * this chunk as missing.
1533 if (!transport
|| !sctp_cacc_skip(primary
, transport
,
1534 count_of_newacks
, tsn
)) {
1535 chunk
->tsn_missing_report
++;
1538 "%s: TSN 0x%x missing counter: %d\n",
1540 chunk
->tsn_missing_report
);
1544 * M4) If any DATA chunk is found to have a
1545 * 'TSN.Missing.Report'
1546 * value larger than or equal to 4, mark that chunk for
1547 * retransmission and start the fast retransmit procedure.
1550 if (chunk
->tsn_missing_report
>= 4) {
1551 chunk
->fast_retransmit
= 1;
1552 do_fast_retransmit
= 1;
1557 if (do_fast_retransmit
)
1558 sctp_retransmit(q
, transport
, SCTP_RTXR_FAST_RTX
);
1560 SCTP_DEBUG_PRINTK("%s: transport: %p, cwnd: %d, "
1561 "ssthresh: %d, flight_size: %d, pba: %d\n",
1562 __FUNCTION__
, transport
, transport
->cwnd
,
1563 transport
->ssthresh
, transport
->flight_size
,
1564 transport
->partial_bytes_acked
);
1568 /* Is the given TSN acked by this packet? */
1569 static int sctp_acked(struct sctp_sackhdr
*sack
, __u32 tsn
)
1572 sctp_sack_variable_t
*frags
;
1574 __u32 ctsn
= ntohl(sack
->cum_tsn_ack
);
1576 if (TSN_lte(tsn
, ctsn
))
1579 /* 3.3.4 Selective Acknowledgement (SACK) (3):
1582 * These fields contain the Gap Ack Blocks. They are repeated
1583 * for each Gap Ack Block up to the number of Gap Ack Blocks
1584 * defined in the Number of Gap Ack Blocks field. All DATA
1585 * chunks with TSNs greater than or equal to (Cumulative TSN
1586 * Ack + Gap Ack Block Start) and less than or equal to
1587 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack
1588 * Block are assumed to have been received correctly.
1591 frags
= sack
->variable
;
1593 for (i
= 0; i
< ntohs(sack
->num_gap_ack_blocks
); ++i
) {
1594 if (TSN_lte(ntohs(frags
[i
].gab
.start
), gap
) &&
1595 TSN_lte(gap
, ntohs(frags
[i
].gab
.end
)))