1 /* SCTP kernel implementation
2 * (C) Copyright IBM Corp. 2001, 2004
3 * Copyright (c) 1999-2000 Cisco, Inc.
4 * Copyright (c) 1999-2001 Motorola, Inc.
5 * Copyright (c) 2001-2003 Intel Corp.
7 * This file is part of the SCTP kernel implementation
9 * These functions implement the sctp_outq class. The outqueue handles
10 * bundling and queueing of outgoing SCTP chunks.
12 * This SCTP implementation is free software;
13 * you can redistribute it and/or modify it under the terms of
14 * the GNU General Public License as published by
15 * the Free Software Foundation; either version 2, or (at your option)
18 * This SCTP implementation is distributed in the hope that it
19 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
20 * ************************
21 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
22 * See the GNU General Public License for more details.
24 * You should have received a copy of the GNU General Public License
25 * along with GNU CC; see the file COPYING. If not, write to
26 * the Free Software Foundation, 59 Temple Place - Suite 330,
27 * Boston, MA 02111-1307, USA.
29 * Please send any bug reports or fixes you make to the
31 * lksctp developers <lksctp-developers@lists.sourceforge.net>
33 * Or submit a bug report through the following website:
34 * http://www.sf.net/projects/lksctp
36 * Written or modified by:
37 * La Monte H.P. Yarroll <piggy@acm.org>
38 * Karl Knutson <karl@athena.chicago.il.us>
39 * Perry Melange <pmelange@null.cc.uic.edu>
40 * Xingang Guo <xingang.guo@intel.com>
41 * Hui Huang <hui.huang@nokia.com>
42 * Sridhar Samudrala <sri@us.ibm.com>
43 * Jon Grimm <jgrimm@us.ibm.com>
45 * Any bugs reported given to us we will try to fix... any fixes shared will
46 * be incorporated into the next SCTP release.
49 #include <linux/types.h>
50 #include <linux/list.h> /* For struct list_head */
51 #include <linux/socket.h>
53 #include <linux/slab.h>
54 #include <net/sock.h> /* For skb_set_owner_w */
56 #include <net/sctp/sctp.h>
57 #include <net/sctp/sm.h>
59 /* Declare internal functions here. */
60 static int sctp_acked(struct sctp_sackhdr
*sack
, __u32 tsn
);
61 static void sctp_check_transmitted(struct sctp_outq
*q
,
62 struct list_head
*transmitted_queue
,
63 struct sctp_transport
*transport
,
64 struct sctp_sackhdr
*sack
,
65 __u32 highest_new_tsn
);
67 static void sctp_mark_missing(struct sctp_outq
*q
,
68 struct list_head
*transmitted_queue
,
69 struct sctp_transport
*transport
,
70 __u32 highest_new_tsn
,
71 int count_of_newacks
);
73 static void sctp_generate_fwdtsn(struct sctp_outq
*q
, __u32 sack_ctsn
);
75 static int sctp_outq_flush(struct sctp_outq
*q
, int rtx_timeout
);
77 /* Add data to the front of the queue. */
78 static inline void sctp_outq_head_data(struct sctp_outq
*q
,
79 struct sctp_chunk
*ch
)
81 list_add(&ch
->list
, &q
->out_chunk_list
);
82 q
->out_qlen
+= ch
->skb
->len
;
86 /* Take data from the front of the queue. */
87 static inline struct sctp_chunk
*sctp_outq_dequeue_data(struct sctp_outq
*q
)
89 struct sctp_chunk
*ch
= NULL
;
91 if (!list_empty(&q
->out_chunk_list
)) {
92 struct list_head
*entry
= q
->out_chunk_list
.next
;
94 ch
= list_entry(entry
, struct sctp_chunk
, list
);
96 q
->out_qlen
-= ch
->skb
->len
;
100 /* Add data chunk to the end of the queue. */
101 static inline void sctp_outq_tail_data(struct sctp_outq
*q
,
102 struct sctp_chunk
*ch
)
104 list_add_tail(&ch
->list
, &q
->out_chunk_list
);
105 q
->out_qlen
+= ch
->skb
->len
;
110 * SFR-CACC algorithm:
111 * D) If count_of_newacks is greater than or equal to 2
112 * and t was not sent to the current primary then the
113 * sender MUST NOT increment missing report count for t.
115 static inline int sctp_cacc_skip_3_1_d(struct sctp_transport
*primary
,
116 struct sctp_transport
*transport
,
117 int count_of_newacks
)
119 if (count_of_newacks
>=2 && transport
!= primary
)
125 * SFR-CACC algorithm:
126 * F) If count_of_newacks is less than 2, let d be the
127 * destination to which t was sent. If cacc_saw_newack
128 * is 0 for destination d, then the sender MUST NOT
129 * increment missing report count for t.
131 static inline int sctp_cacc_skip_3_1_f(struct sctp_transport
*transport
,
132 int count_of_newacks
)
134 if (count_of_newacks
< 2 && !transport
->cacc
.cacc_saw_newack
)
140 * SFR-CACC algorithm:
141 * 3.1) If CYCLING_CHANGEOVER is 0, the sender SHOULD
142 * execute steps C, D, F.
144 * C has been implemented in sctp_outq_sack
146 static inline int sctp_cacc_skip_3_1(struct sctp_transport
*primary
,
147 struct sctp_transport
*transport
,
148 int count_of_newacks
)
150 if (!primary
->cacc
.cycling_changeover
) {
151 if (sctp_cacc_skip_3_1_d(primary
, transport
, count_of_newacks
))
153 if (sctp_cacc_skip_3_1_f(transport
, count_of_newacks
))
161 * SFR-CACC algorithm:
162 * 3.2) Else if CYCLING_CHANGEOVER is 1, and t is less
163 * than next_tsn_at_change of the current primary, then
164 * the sender MUST NOT increment missing report count
167 static inline int sctp_cacc_skip_3_2(struct sctp_transport
*primary
, __u32 tsn
)
169 if (primary
->cacc
.cycling_changeover
&&
170 TSN_lt(tsn
, primary
->cacc
.next_tsn_at_change
))
176 * SFR-CACC algorithm:
177 * 3) If the missing report count for TSN t is to be
178 * incremented according to [RFC2960] and
179 * [SCTP_STEWART-2002], and CHANGEOVER_ACTIVE is set,
180 * then the sender MUST futher execute steps 3.1 and
181 * 3.2 to determine if the missing report count for
182 * TSN t SHOULD NOT be incremented.
184 * 3.3) If 3.1 and 3.2 do not dictate that the missing
185 * report count for t should not be incremented, then
186 * the sender SOULD increment missing report count for
187 * t (according to [RFC2960] and [SCTP_STEWART_2002]).
189 static inline int sctp_cacc_skip(struct sctp_transport
*primary
,
190 struct sctp_transport
*transport
,
191 int count_of_newacks
,
194 if (primary
->cacc
.changeover_active
&&
195 (sctp_cacc_skip_3_1(primary
, transport
, count_of_newacks
) ||
196 sctp_cacc_skip_3_2(primary
, tsn
)))
201 /* Initialize an existing sctp_outq. This does the boring stuff.
202 * You still need to define handlers if you really want to DO
203 * something with this structure...
205 void sctp_outq_init(struct sctp_association
*asoc
, struct sctp_outq
*q
)
208 INIT_LIST_HEAD(&q
->out_chunk_list
);
209 INIT_LIST_HEAD(&q
->control_chunk_list
);
210 INIT_LIST_HEAD(&q
->retransmit
);
211 INIT_LIST_HEAD(&q
->sacked
);
212 INIT_LIST_HEAD(&q
->abandoned
);
215 q
->outstanding_bytes
= 0;
223 /* Free the outqueue structure and any related pending chunks.
225 void sctp_outq_teardown(struct sctp_outq
*q
)
227 struct sctp_transport
*transport
;
228 struct list_head
*lchunk
, *temp
;
229 struct sctp_chunk
*chunk
, *tmp
;
231 /* Throw away unacknowledged chunks. */
232 list_for_each_entry(transport
, &q
->asoc
->peer
.transport_addr_list
,
234 while ((lchunk
= sctp_list_dequeue(&transport
->transmitted
)) != NULL
) {
235 chunk
= list_entry(lchunk
, struct sctp_chunk
,
237 /* Mark as part of a failed message. */
238 sctp_chunk_fail(chunk
, q
->error
);
239 sctp_chunk_free(chunk
);
243 /* Throw away chunks that have been gap ACKed. */
244 list_for_each_safe(lchunk
, temp
, &q
->sacked
) {
245 list_del_init(lchunk
);
246 chunk
= list_entry(lchunk
, struct sctp_chunk
,
248 sctp_chunk_fail(chunk
, q
->error
);
249 sctp_chunk_free(chunk
);
252 /* Throw away any chunks in the retransmit queue. */
253 list_for_each_safe(lchunk
, temp
, &q
->retransmit
) {
254 list_del_init(lchunk
);
255 chunk
= list_entry(lchunk
, struct sctp_chunk
,
257 sctp_chunk_fail(chunk
, q
->error
);
258 sctp_chunk_free(chunk
);
261 /* Throw away any chunks that are in the abandoned queue. */
262 list_for_each_safe(lchunk
, temp
, &q
->abandoned
) {
263 list_del_init(lchunk
);
264 chunk
= list_entry(lchunk
, struct sctp_chunk
,
266 sctp_chunk_fail(chunk
, q
->error
);
267 sctp_chunk_free(chunk
);
270 /* Throw away any leftover data chunks. */
271 while ((chunk
= sctp_outq_dequeue_data(q
)) != NULL
) {
273 /* Mark as send failure. */
274 sctp_chunk_fail(chunk
, q
->error
);
275 sctp_chunk_free(chunk
);
280 /* Throw away any leftover control chunks. */
281 list_for_each_entry_safe(chunk
, tmp
, &q
->control_chunk_list
, list
) {
282 list_del_init(&chunk
->list
);
283 sctp_chunk_free(chunk
);
287 /* Free the outqueue structure and any related pending chunks. */
288 void sctp_outq_free(struct sctp_outq
*q
)
290 /* Throw away leftover chunks. */
291 sctp_outq_teardown(q
);
293 /* If we were kmalloc()'d, free the memory. */
298 /* Put a new chunk in an sctp_outq. */
299 int sctp_outq_tail(struct sctp_outq
*q
, struct sctp_chunk
*chunk
)
303 SCTP_DEBUG_PRINTK("sctp_outq_tail(%p, %p[%s])\n",
304 q
, chunk
, chunk
&& chunk
->chunk_hdr
?
305 sctp_cname(SCTP_ST_CHUNK(chunk
->chunk_hdr
->type
))
308 /* If it is data, queue it up, otherwise, send it
311 if (sctp_chunk_is_data(chunk
)) {
312 /* Is it OK to queue data chunks? */
313 /* From 9. Termination of Association
315 * When either endpoint performs a shutdown, the
316 * association on each peer will stop accepting new
317 * data from its user and only deliver data in queue
318 * at the time of sending or receiving the SHUTDOWN
321 switch (q
->asoc
->state
) {
322 case SCTP_STATE_EMPTY
:
323 case SCTP_STATE_CLOSED
:
324 case SCTP_STATE_SHUTDOWN_PENDING
:
325 case SCTP_STATE_SHUTDOWN_SENT
:
326 case SCTP_STATE_SHUTDOWN_RECEIVED
:
327 case SCTP_STATE_SHUTDOWN_ACK_SENT
:
328 /* Cannot send after transport endpoint shutdown */
333 SCTP_DEBUG_PRINTK("outqueueing (%p, %p[%s])\n",
334 q
, chunk
, chunk
&& chunk
->chunk_hdr
?
335 sctp_cname(SCTP_ST_CHUNK(chunk
->chunk_hdr
->type
))
338 sctp_outq_tail_data(q
, chunk
);
339 if (chunk
->chunk_hdr
->flags
& SCTP_DATA_UNORDERED
)
340 SCTP_INC_STATS(SCTP_MIB_OUTUNORDERCHUNKS
);
342 SCTP_INC_STATS(SCTP_MIB_OUTORDERCHUNKS
);
347 list_add_tail(&chunk
->list
, &q
->control_chunk_list
);
348 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS
);
355 error
= sctp_outq_flush(q
, 0);
360 /* Insert a chunk into the sorted list based on the TSNs. The retransmit list
361 * and the abandoned list are in ascending order.
363 static void sctp_insert_list(struct list_head
*head
, struct list_head
*new)
365 struct list_head
*pos
;
366 struct sctp_chunk
*nchunk
, *lchunk
;
370 nchunk
= list_entry(new, struct sctp_chunk
, transmitted_list
);
371 ntsn
= ntohl(nchunk
->subh
.data_hdr
->tsn
);
373 list_for_each(pos
, head
) {
374 lchunk
= list_entry(pos
, struct sctp_chunk
, transmitted_list
);
375 ltsn
= ntohl(lchunk
->subh
.data_hdr
->tsn
);
376 if (TSN_lt(ntsn
, ltsn
)) {
377 list_add(new, pos
->prev
);
383 list_add_tail(new, head
);
386 /* Mark all the eligible packets on a transport for retransmission. */
387 void sctp_retransmit_mark(struct sctp_outq
*q
,
388 struct sctp_transport
*transport
,
391 struct list_head
*lchunk
, *ltemp
;
392 struct sctp_chunk
*chunk
;
394 /* Walk through the specified transmitted queue. */
395 list_for_each_safe(lchunk
, ltemp
, &transport
->transmitted
) {
396 chunk
= list_entry(lchunk
, struct sctp_chunk
,
399 /* If the chunk is abandoned, move it to abandoned list. */
400 if (sctp_chunk_abandoned(chunk
)) {
401 list_del_init(lchunk
);
402 sctp_insert_list(&q
->abandoned
, lchunk
);
404 /* If this chunk has not been previousely acked,
405 * stop considering it 'outstanding'. Our peer
406 * will most likely never see it since it will
407 * not be retransmitted
409 if (!chunk
->tsn_gap_acked
) {
410 if (chunk
->transport
)
411 chunk
->transport
->flight_size
-=
412 sctp_data_size(chunk
);
413 q
->outstanding_bytes
-= sctp_data_size(chunk
);
414 q
->asoc
->peer
.rwnd
+= (sctp_data_size(chunk
) +
415 sizeof(struct sk_buff
));
420 /* If we are doing retransmission due to a timeout or pmtu
421 * discovery, only the chunks that are not yet acked should
422 * be added to the retransmit queue.
424 if ((reason
== SCTP_RTXR_FAST_RTX
&&
425 (chunk
->fast_retransmit
== SCTP_NEED_FRTX
)) ||
426 (reason
!= SCTP_RTXR_FAST_RTX
&& !chunk
->tsn_gap_acked
)) {
427 /* RFC 2960 6.2.1 Processing a Received SACK
429 * C) Any time a DATA chunk is marked for
430 * retransmission (via either T3-rtx timer expiration
431 * (Section 6.3.3) or via fast retransmit
432 * (Section 7.2.4)), add the data size of those
433 * chunks to the rwnd.
435 q
->asoc
->peer
.rwnd
+= (sctp_data_size(chunk
) +
436 sizeof(struct sk_buff
));
437 q
->outstanding_bytes
-= sctp_data_size(chunk
);
438 if (chunk
->transport
)
439 transport
->flight_size
-= sctp_data_size(chunk
);
441 /* sctpimpguide-05 Section 2.8.2
442 * M5) If a T3-rtx timer expires, the
443 * 'TSN.Missing.Report' of all affected TSNs is set
446 chunk
->tsn_missing_report
= 0;
448 /* If a chunk that is being used for RTT measurement
449 * has to be retransmitted, we cannot use this chunk
450 * anymore for RTT measurements. Reset rto_pending so
451 * that a new RTT measurement is started when a new
452 * data chunk is sent.
454 if (chunk
->rtt_in_progress
) {
455 chunk
->rtt_in_progress
= 0;
456 transport
->rto_pending
= 0;
459 /* Move the chunk to the retransmit queue. The chunks
460 * on the retransmit queue are always kept in order.
462 list_del_init(lchunk
);
463 sctp_insert_list(&q
->retransmit
, lchunk
);
467 SCTP_DEBUG_PRINTK("%s: transport: %p, reason: %d, "
468 "cwnd: %d, ssthresh: %d, flight_size: %d, "
469 "pba: %d\n", __func__
,
471 transport
->cwnd
, transport
->ssthresh
,
472 transport
->flight_size
,
473 transport
->partial_bytes_acked
);
477 /* Mark all the eligible packets on a transport for retransmission and force
480 void sctp_retransmit(struct sctp_outq
*q
, struct sctp_transport
*transport
,
481 sctp_retransmit_reason_t reason
)
486 case SCTP_RTXR_T3_RTX
:
487 SCTP_INC_STATS(SCTP_MIB_T3_RETRANSMITS
);
488 sctp_transport_lower_cwnd(transport
, SCTP_LOWER_CWND_T3_RTX
);
489 /* Update the retran path if the T3-rtx timer has expired for
490 * the current retran path.
492 if (transport
== transport
->asoc
->peer
.retran_path
)
493 sctp_assoc_update_retran_path(transport
->asoc
);
494 transport
->asoc
->rtx_data_chunks
+=
495 transport
->asoc
->unack_data
;
497 case SCTP_RTXR_FAST_RTX
:
498 SCTP_INC_STATS(SCTP_MIB_FAST_RETRANSMITS
);
499 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
);
507 transport
->asoc
->init_retries
++;
513 sctp_retransmit_mark(q
, transport
, reason
);
515 /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination,
516 * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by
517 * following the procedures outlined in C1 - C5.
519 if (reason
== SCTP_RTXR_T3_RTX
)
520 sctp_generate_fwdtsn(q
, q
->asoc
->ctsn_ack_point
);
522 /* Flush the queues only on timeout, since fast_rtx is only
523 * triggered during sack processing and the queue
524 * will be flushed at the end.
526 if (reason
!= SCTP_RTXR_FAST_RTX
)
527 error
= sctp_outq_flush(q
, /* rtx_timeout */ 1);
530 q
->asoc
->base
.sk
->sk_err
= -error
;
534 * Transmit DATA chunks on the retransmit queue. Upon return from
535 * sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which
536 * need to be transmitted by the caller.
537 * We assume that pkt->transport has already been set.
539 * The return value is a normal kernel error return value.
541 static int sctp_outq_flush_rtx(struct sctp_outq
*q
, struct sctp_packet
*pkt
,
542 int rtx_timeout
, int *start_timer
)
544 struct list_head
*lqueue
;
545 struct sctp_transport
*transport
= pkt
->transport
;
547 struct sctp_chunk
*chunk
, *chunk1
;
548 struct sctp_association
*asoc
;
555 lqueue
= &q
->retransmit
;
556 fast_rtx
= q
->fast_rtx
;
558 /* This loop handles time-out retransmissions, fast retransmissions,
559 * and retransmissions due to opening of whindow.
561 * RFC 2960 6.3.3 Handle T3-rtx Expiration
563 * E3) Determine how many of the earliest (i.e., lowest TSN)
564 * outstanding DATA chunks for the address for which the
565 * T3-rtx has expired will fit into a single packet, subject
566 * to the MTU constraint for the path corresponding to the
567 * destination transport address to which the retransmission
568 * is being sent (this may be different from the address for
569 * which the timer expires [see Section 6.4]). Call this value
570 * K. Bundle and retransmit those K DATA chunks in a single
571 * packet to the destination endpoint.
573 * [Just to be painfully clear, if we are retransmitting
574 * because a timeout just happened, we should send only ONE
575 * packet of retransmitted data.]
577 * For fast retransmissions we also send only ONE packet. However,
578 * if we are just flushing the queue due to open window, we'll
579 * try to send as much as possible.
581 list_for_each_entry_safe(chunk
, chunk1
, lqueue
, transmitted_list
) {
583 /* Make sure that Gap Acked TSNs are not retransmitted. A
584 * simple approach is just to move such TSNs out of the
585 * way and into a 'transmitted' queue and skip to the
588 if (chunk
->tsn_gap_acked
) {
589 list_del(&chunk
->transmitted_list
);
590 list_add_tail(&chunk
->transmitted_list
,
591 &transport
->transmitted
);
595 /* If we are doing fast retransmit, ignore non-fast_rtransmit
598 if (fast_rtx
&& !chunk
->fast_retransmit
)
602 /* Attempt to append this chunk to the packet. */
603 status
= sctp_packet_append_chunk(pkt
, chunk
);
606 case SCTP_XMIT_PMTU_FULL
:
607 if (!pkt
->has_data
&& !pkt
->has_cookie_echo
) {
608 /* If this packet did not contain DATA then
609 * retransmission did not happen, so do it
610 * again. We'll ignore the error here since
611 * control chunks are already freed so there
612 * is nothing we can do.
614 sctp_packet_transmit(pkt
);
618 /* Send this packet. */
619 error
= sctp_packet_transmit(pkt
);
621 /* If we are retransmitting, we should only
622 * send a single packet.
624 if (rtx_timeout
|| fast_rtx
)
627 /* Bundle next chunk in the next round. */
630 case SCTP_XMIT_RWND_FULL
:
631 /* Send this packet. */
632 error
= sctp_packet_transmit(pkt
);
634 /* Stop sending DATA as there is no more room
640 case SCTP_XMIT_NAGLE_DELAY
:
641 /* Send this packet. */
642 error
= sctp_packet_transmit(pkt
);
644 /* Stop sending DATA because of nagle delay. */
649 /* The append was successful, so add this chunk to
650 * the transmitted list.
652 list_del(&chunk
->transmitted_list
);
653 list_add_tail(&chunk
->transmitted_list
,
654 &transport
->transmitted
);
656 /* Mark the chunk as ineligible for fast retransmit
657 * after it is retransmitted.
659 if (chunk
->fast_retransmit
== SCTP_NEED_FRTX
)
660 chunk
->fast_retransmit
= SCTP_DONT_FRTX
;
666 /* Set the timer if there were no errors */
667 if (!error
&& !timer
)
674 /* If we are here due to a retransmit timeout or a fast
675 * retransmit and if there are any chunks left in the retransmit
676 * queue that could not fit in the PMTU sized packet, they need
677 * to be marked as ineligible for a subsequent fast retransmit.
679 if (rtx_timeout
|| fast_rtx
) {
680 list_for_each_entry(chunk1
, lqueue
, transmitted_list
) {
681 if (chunk1
->fast_retransmit
== SCTP_NEED_FRTX
)
682 chunk1
->fast_retransmit
= SCTP_DONT_FRTX
;
686 *start_timer
= timer
;
688 /* Clear fast retransmit hint */
695 /* Cork the outqueue so queued chunks are really queued. */
696 int sctp_outq_uncork(struct sctp_outq
*q
)
701 error
= sctp_outq_flush(q
, 0);
707 * Try to flush an outqueue.
709 * Description: Send everything in q which we legally can, subject to
710 * congestion limitations.
711 * * Note: This function can be called from multiple contexts so appropriate
712 * locking concerns must be made. Today we use the sock lock to protect
715 static int sctp_outq_flush(struct sctp_outq
*q
, int rtx_timeout
)
717 struct sctp_packet
*packet
;
718 struct sctp_packet singleton
;
719 struct sctp_association
*asoc
= q
->asoc
;
720 __u16 sport
= asoc
->base
.bind_addr
.port
;
721 __u16 dport
= asoc
->peer
.port
;
722 __u32 vtag
= asoc
->peer
.i
.init_tag
;
723 struct sctp_transport
*transport
= NULL
;
724 struct sctp_transport
*new_transport
;
725 struct sctp_chunk
*chunk
, *tmp
;
731 /* These transports have chunks to send. */
732 struct list_head transport_list
;
733 struct list_head
*ltransport
;
735 INIT_LIST_HEAD(&transport_list
);
741 * When bundling control chunks with DATA chunks, an
742 * endpoint MUST place control chunks first in the outbound
743 * SCTP packet. The transmitter MUST transmit DATA chunks
744 * within a SCTP packet in increasing order of TSN.
748 list_for_each_entry_safe(chunk
, tmp
, &q
->control_chunk_list
, list
) {
749 list_del_init(&chunk
->list
);
751 /* Pick the right transport to use. */
752 new_transport
= chunk
->transport
;
754 if (!new_transport
) {
756 * If we have a prior transport pointer, see if
757 * the destination address of the chunk
758 * matches the destination address of the
759 * current transport. If not a match, then
760 * try to look up the transport with a given
761 * destination address. We do this because
762 * after processing ASCONFs, we may have new
763 * transports created.
766 sctp_cmp_addr_exact(&chunk
->dest
,
768 new_transport
= transport
;
770 new_transport
= sctp_assoc_lookup_paddr(asoc
,
773 /* if we still don't have a new transport, then
774 * use the current active path.
777 new_transport
= asoc
->peer
.active_path
;
778 } else if ((new_transport
->state
== SCTP_INACTIVE
) ||
779 (new_transport
->state
== SCTP_UNCONFIRMED
)) {
780 /* If the chunk is Heartbeat or Heartbeat Ack,
781 * send it to chunk->transport, even if it's
784 * 3.3.6 Heartbeat Acknowledgement:
786 * A HEARTBEAT ACK is always sent to the source IP
787 * address of the IP datagram containing the
788 * HEARTBEAT chunk to which this ack is responding.
791 * ASCONF_ACKs also must be sent to the source.
793 if (chunk
->chunk_hdr
->type
!= SCTP_CID_HEARTBEAT
&&
794 chunk
->chunk_hdr
->type
!= SCTP_CID_HEARTBEAT_ACK
&&
795 chunk
->chunk_hdr
->type
!= SCTP_CID_ASCONF_ACK
)
796 new_transport
= asoc
->peer
.active_path
;
799 /* Are we switching transports?
800 * Take care of transport locks.
802 if (new_transport
!= transport
) {
803 transport
= new_transport
;
804 if (list_empty(&transport
->send_ready
)) {
805 list_add_tail(&transport
->send_ready
,
808 packet
= &transport
->packet
;
809 sctp_packet_config(packet
, vtag
,
810 asoc
->peer
.ecn_capable
);
813 switch (chunk
->chunk_hdr
->type
) {
817 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN
818 * COMPLETE with any other chunks. [Send them immediately.]
821 case SCTP_CID_INIT_ACK
:
822 case SCTP_CID_SHUTDOWN_COMPLETE
:
823 sctp_packet_init(&singleton
, transport
, sport
, dport
);
824 sctp_packet_config(&singleton
, vtag
, 0);
825 sctp_packet_append_chunk(&singleton
, chunk
);
826 error
= sctp_packet_transmit(&singleton
);
832 if (sctp_test_T_bit(chunk
)) {
833 packet
->vtag
= asoc
->c
.my_vtag
;
835 /* The following chunks are "response" chunks, i.e.
836 * they are generated in response to something we
837 * received. If we are sending these, then we can
838 * send only 1 packet containing these chunks.
840 case SCTP_CID_HEARTBEAT_ACK
:
841 case SCTP_CID_SHUTDOWN_ACK
:
842 case SCTP_CID_COOKIE_ACK
:
843 case SCTP_CID_COOKIE_ECHO
:
845 case SCTP_CID_ECN_CWR
:
846 case SCTP_CID_ASCONF_ACK
:
851 case SCTP_CID_HEARTBEAT
:
852 case SCTP_CID_SHUTDOWN
:
853 case SCTP_CID_ECN_ECNE
:
854 case SCTP_CID_ASCONF
:
855 case SCTP_CID_FWD_TSN
:
856 status
= sctp_packet_transmit_chunk(packet
, chunk
,
858 if (status
!= SCTP_XMIT_OK
) {
859 /* put the chunk back */
860 list_add(&chunk
->list
, &q
->control_chunk_list
);
861 } else if (chunk
->chunk_hdr
->type
== SCTP_CID_FWD_TSN
) {
862 /* PR-SCTP C5) If a FORWARD TSN is sent, the
863 * sender MUST assure that at least one T3-rtx
866 sctp_transport_reset_timers(transport
);
871 /* We built a chunk with an illegal type! */
876 /* Is it OK to send data chunks? */
877 switch (asoc
->state
) {
878 case SCTP_STATE_COOKIE_ECHOED
:
879 /* Only allow bundling when this packet has a COOKIE-ECHO
882 if (!packet
|| !packet
->has_cookie_echo
)
886 case SCTP_STATE_ESTABLISHED
:
887 case SCTP_STATE_SHUTDOWN_PENDING
:
888 case SCTP_STATE_SHUTDOWN_RECEIVED
:
890 * RFC 2960 6.1 Transmission of DATA Chunks
892 * C) When the time comes for the sender to transmit,
893 * before sending new DATA chunks, the sender MUST
894 * first transmit any outstanding DATA chunks which
895 * are marked for retransmission (limited by the
898 if (!list_empty(&q
->retransmit
)) {
899 if (transport
== asoc
->peer
.retran_path
)
902 /* Switch transports & prepare the packet. */
904 transport
= asoc
->peer
.retran_path
;
906 if (list_empty(&transport
->send_ready
)) {
907 list_add_tail(&transport
->send_ready
,
911 packet
= &transport
->packet
;
912 sctp_packet_config(packet
, vtag
,
913 asoc
->peer
.ecn_capable
);
915 error
= sctp_outq_flush_rtx(q
, packet
,
916 rtx_timeout
, &start_timer
);
919 sctp_transport_reset_timers(transport
);
921 /* This can happen on COOKIE-ECHO resend. Only
922 * one chunk can get bundled with a COOKIE-ECHO.
924 if (packet
->has_cookie_echo
)
927 /* Don't send new data if there is still data
928 * waiting to retransmit.
930 if (!list_empty(&q
->retransmit
))
934 /* Apply Max.Burst limitation to the current transport in
935 * case it will be used for new data. We are going to
936 * rest it before we return, but we want to apply the limit
937 * to the currently queued data.
940 sctp_transport_burst_limited(transport
);
942 /* Finally, transmit new packets. */
943 while ((chunk
= sctp_outq_dequeue_data(q
)) != NULL
) {
944 /* RFC 2960 6.5 Every DATA chunk MUST carry a valid
947 if (chunk
->sinfo
.sinfo_stream
>=
948 asoc
->c
.sinit_num_ostreams
) {
950 /* Mark as failed send. */
951 sctp_chunk_fail(chunk
, SCTP_ERROR_INV_STRM
);
952 sctp_chunk_free(chunk
);
956 /* Has this chunk expired? */
957 if (sctp_chunk_abandoned(chunk
)) {
958 sctp_chunk_fail(chunk
, 0);
959 sctp_chunk_free(chunk
);
963 /* If there is a specified transport, use it.
964 * Otherwise, we want to use the active path.
966 new_transport
= chunk
->transport
;
967 if (!new_transport
||
968 ((new_transport
->state
== SCTP_INACTIVE
) ||
969 (new_transport
->state
== SCTP_UNCONFIRMED
)))
970 new_transport
= asoc
->peer
.active_path
;
972 /* Change packets if necessary. */
973 if (new_transport
!= transport
) {
974 transport
= new_transport
;
976 /* Schedule to have this transport's
979 if (list_empty(&transport
->send_ready
)) {
980 list_add_tail(&transport
->send_ready
,
984 packet
= &transport
->packet
;
985 sctp_packet_config(packet
, vtag
,
986 asoc
->peer
.ecn_capable
);
987 /* We've switched transports, so apply the
988 * Burst limit to the new transport.
990 sctp_transport_burst_limited(transport
);
993 SCTP_DEBUG_PRINTK("sctp_outq_flush(%p, %p[%s]), ",
995 chunk
&& chunk
->chunk_hdr
?
996 sctp_cname(SCTP_ST_CHUNK(
997 chunk
->chunk_hdr
->type
))
1000 SCTP_DEBUG_PRINTK("TX TSN 0x%x skb->head "
1001 "%p skb->users %d.\n",
1002 ntohl(chunk
->subh
.data_hdr
->tsn
),
1003 chunk
->skb
?chunk
->skb
->head
: NULL
,
1005 atomic_read(&chunk
->skb
->users
) : -1);
1007 /* Add the chunk to the packet. */
1008 status
= sctp_packet_transmit_chunk(packet
, chunk
, 0);
1011 case SCTP_XMIT_PMTU_FULL
:
1012 case SCTP_XMIT_RWND_FULL
:
1013 case SCTP_XMIT_NAGLE_DELAY
:
1014 /* We could not append this chunk, so put
1015 * the chunk back on the output queue.
1017 SCTP_DEBUG_PRINTK("sctp_outq_flush: could "
1018 "not transmit TSN: 0x%x, status: %d\n",
1019 ntohl(chunk
->subh
.data_hdr
->tsn
),
1021 sctp_outq_head_data(q
, chunk
);
1022 goto sctp_flush_out
;
1026 /* The sender is in the SHUTDOWN-PENDING state,
1027 * The sender MAY set the I-bit in the DATA
1030 if (asoc
->state
== SCTP_STATE_SHUTDOWN_PENDING
)
1031 chunk
->chunk_hdr
->flags
|= SCTP_DATA_SACK_IMM
;
1039 /* BUG: We assume that the sctp_packet_transmit()
1040 * call below will succeed all the time and add the
1041 * chunk to the transmitted list and restart the
1043 * It is possible that the call can fail under OOM
1046 * Is this really a problem? Won't this behave
1049 list_add_tail(&chunk
->transmitted_list
,
1050 &transport
->transmitted
);
1052 sctp_transport_reset_timers(transport
);
1056 /* Only let one DATA chunk get bundled with a
1057 * COOKIE-ECHO chunk.
1059 if (packet
->has_cookie_echo
)
1060 goto sctp_flush_out
;
1071 /* Before returning, examine all the transports touched in
1072 * this call. Right now, we bluntly force clear all the
1073 * transports. Things might change after we implement Nagle.
1074 * But such an examination is still required.
1078 while ((ltransport
= sctp_list_dequeue(&transport_list
)) != NULL
) {
1079 struct sctp_transport
*t
= list_entry(ltransport
,
1080 struct sctp_transport
,
1082 packet
= &t
->packet
;
1083 if (!sctp_packet_empty(packet
))
1084 error
= sctp_packet_transmit(packet
);
1086 /* Clear the burst limited state, if any */
1087 sctp_transport_burst_reset(t
);
1093 /* Update unack_data based on the incoming SACK chunk */
1094 static void sctp_sack_update_unack_data(struct sctp_association
*assoc
,
1095 struct sctp_sackhdr
*sack
)
1097 sctp_sack_variable_t
*frags
;
1101 unack_data
= assoc
->next_tsn
- assoc
->ctsn_ack_point
- 1;
1103 frags
= sack
->variable
;
1104 for (i
= 0; i
< ntohs(sack
->num_gap_ack_blocks
); i
++) {
1105 unack_data
-= ((ntohs(frags
[i
].gab
.end
) -
1106 ntohs(frags
[i
].gab
.start
) + 1));
1109 assoc
->unack_data
= unack_data
;
1112 /* Return the highest new tsn that is acknowledged by the given SACK chunk. */
1113 static __u32
sctp_highest_new_tsn(struct sctp_sackhdr
*sack
,
1114 struct sctp_association
*asoc
)
1116 struct sctp_transport
*transport
;
1117 struct sctp_chunk
*chunk
;
1118 __u32 highest_new_tsn
, tsn
;
1119 struct list_head
*transport_list
= &asoc
->peer
.transport_addr_list
;
1121 highest_new_tsn
= ntohl(sack
->cum_tsn_ack
);
1123 list_for_each_entry(transport
, transport_list
, transports
) {
1124 list_for_each_entry(chunk
, &transport
->transmitted
,
1126 tsn
= ntohl(chunk
->subh
.data_hdr
->tsn
);
1128 if (!chunk
->tsn_gap_acked
&&
1129 TSN_lt(highest_new_tsn
, tsn
) &&
1130 sctp_acked(sack
, tsn
))
1131 highest_new_tsn
= tsn
;
1135 return highest_new_tsn
;
1138 /* This is where we REALLY process a SACK.
1140 * Process the SACK against the outqueue. Mostly, this just frees
1141 * things off the transmitted queue.
1143 int sctp_outq_sack(struct sctp_outq
*q
, struct sctp_sackhdr
*sack
)
1145 struct sctp_association
*asoc
= q
->asoc
;
1146 struct sctp_transport
*transport
;
1147 struct sctp_chunk
*tchunk
= NULL
;
1148 struct list_head
*lchunk
, *transport_list
, *temp
;
1149 sctp_sack_variable_t
*frags
= sack
->variable
;
1150 __u32 sack_ctsn
, ctsn
, tsn
;
1151 __u32 highest_tsn
, highest_new_tsn
;
1153 unsigned outstanding
;
1154 struct sctp_transport
*primary
= asoc
->peer
.primary_path
;
1155 int count_of_newacks
= 0;
1159 /* Grab the association's destination address list. */
1160 transport_list
= &asoc
->peer
.transport_addr_list
;
1162 sack_ctsn
= ntohl(sack
->cum_tsn_ack
);
1163 gap_ack_blocks
= ntohs(sack
->num_gap_ack_blocks
);
1165 * SFR-CACC algorithm:
1166 * On receipt of a SACK the sender SHOULD execute the
1167 * following statements.
1169 * 1) If the cumulative ack in the SACK passes next tsn_at_change
1170 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be
1171 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for
1173 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE
1174 * is set the receiver of the SACK MUST take the following actions:
1176 * A) Initialize the cacc_saw_newack to 0 for all destination
1179 * Only bother if changeover_active is set. Otherwise, this is
1180 * totally suboptimal to do on every SACK.
1182 if (primary
->cacc
.changeover_active
) {
1183 u8 clear_cycling
= 0;
1185 if (TSN_lte(primary
->cacc
.next_tsn_at_change
, sack_ctsn
)) {
1186 primary
->cacc
.changeover_active
= 0;
1190 if (clear_cycling
|| gap_ack_blocks
) {
1191 list_for_each_entry(transport
, transport_list
,
1194 transport
->cacc
.cycling_changeover
= 0;
1196 transport
->cacc
.cacc_saw_newack
= 0;
1201 /* Get the highest TSN in the sack. */
1202 highest_tsn
= sack_ctsn
;
1204 highest_tsn
+= ntohs(frags
[gap_ack_blocks
- 1].gab
.end
);
1206 if (TSN_lt(asoc
->highest_sacked
, highest_tsn
)) {
1207 highest_new_tsn
= highest_tsn
;
1208 asoc
->highest_sacked
= highest_tsn
;
1210 highest_new_tsn
= sctp_highest_new_tsn(sack
, asoc
);
1214 /* Run through the retransmit queue. Credit bytes received
1215 * and free those chunks that we can.
1217 sctp_check_transmitted(q
, &q
->retransmit
, NULL
, sack
, highest_new_tsn
);
1219 /* Run through the transmitted queue.
1220 * Credit bytes received and free those chunks which we can.
1222 * This is a MASSIVE candidate for optimization.
1224 list_for_each_entry(transport
, transport_list
, transports
) {
1225 sctp_check_transmitted(q
, &transport
->transmitted
,
1226 transport
, sack
, highest_new_tsn
);
1228 * SFR-CACC algorithm:
1229 * C) Let count_of_newacks be the number of
1230 * destinations for which cacc_saw_newack is set.
1232 if (transport
->cacc
.cacc_saw_newack
)
1233 count_of_newacks
++;
1236 /* Move the Cumulative TSN Ack Point if appropriate. */
1237 if (TSN_lt(asoc
->ctsn_ack_point
, sack_ctsn
)) {
1238 asoc
->ctsn_ack_point
= sack_ctsn
;
1242 if (gap_ack_blocks
) {
1244 if (asoc
->fast_recovery
&& accum_moved
)
1245 highest_new_tsn
= highest_tsn
;
1247 list_for_each_entry(transport
, transport_list
, transports
)
1248 sctp_mark_missing(q
, &transport
->transmitted
, transport
,
1249 highest_new_tsn
, count_of_newacks
);
1252 /* Update unack_data field in the assoc. */
1253 sctp_sack_update_unack_data(asoc
, sack
);
1255 ctsn
= asoc
->ctsn_ack_point
;
1257 /* Throw away stuff rotting on the sack queue. */
1258 list_for_each_safe(lchunk
, temp
, &q
->sacked
) {
1259 tchunk
= list_entry(lchunk
, struct sctp_chunk
,
1261 tsn
= ntohl(tchunk
->subh
.data_hdr
->tsn
);
1262 if (TSN_lte(tsn
, ctsn
)) {
1263 list_del_init(&tchunk
->transmitted_list
);
1264 sctp_chunk_free(tchunk
);
1268 /* ii) Set rwnd equal to the newly received a_rwnd minus the
1269 * number of bytes still outstanding after processing the
1270 * Cumulative TSN Ack and the Gap Ack Blocks.
1273 sack_a_rwnd
= ntohl(sack
->a_rwnd
);
1274 outstanding
= q
->outstanding_bytes
;
1276 if (outstanding
< sack_a_rwnd
)
1277 sack_a_rwnd
-= outstanding
;
1281 asoc
->peer
.rwnd
= sack_a_rwnd
;
1283 sctp_generate_fwdtsn(q
, sack_ctsn
);
1285 SCTP_DEBUG_PRINTK("%s: sack Cumulative TSN Ack is 0x%x.\n",
1286 __func__
, sack_ctsn
);
1287 SCTP_DEBUG_PRINTK("%s: Cumulative TSN Ack of association, "
1288 "%p is 0x%x. Adv peer ack point: 0x%x\n",
1289 __func__
, asoc
, ctsn
, asoc
->adv_peer_ack_point
);
1291 /* See if all chunks are acked.
1292 * Make sure the empty queue handler will get run later.
1294 q
->empty
= (list_empty(&q
->out_chunk_list
) &&
1295 list_empty(&q
->retransmit
));
1299 list_for_each_entry(transport
, transport_list
, transports
) {
1300 q
->empty
= q
->empty
&& list_empty(&transport
->transmitted
);
1305 SCTP_DEBUG_PRINTK("sack queue is empty.\n");
1310 /* Is the outqueue empty? */
1311 int sctp_outq_is_empty(const struct sctp_outq
*q
)
1316 /********************************************************************
1317 * 2nd Level Abstractions
1318 ********************************************************************/
1320 /* Go through a transport's transmitted list or the association's retransmit
1321 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked.
1322 * The retransmit list will not have an associated transport.
1324 * I added coherent debug information output. --xguo
1326 * Instead of printing 'sacked' or 'kept' for each TSN on the
1327 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5.
1328 * KEPT TSN6-TSN7, etc.
1330 static void sctp_check_transmitted(struct sctp_outq
*q
,
1331 struct list_head
*transmitted_queue
,
1332 struct sctp_transport
*transport
,
1333 struct sctp_sackhdr
*sack
,
1334 __u32 highest_new_tsn_in_sack
)
1336 struct list_head
*lchunk
;
1337 struct sctp_chunk
*tchunk
;
1338 struct list_head tlist
;
1342 __u8 restart_timer
= 0;
1343 int bytes_acked
= 0;
1344 int migrate_bytes
= 0;
1346 /* These state variables are for coherent debug output. --xguo */
1349 __u32 dbg_ack_tsn
= 0; /* An ACKed TSN range starts here... */
1350 __u32 dbg_last_ack_tsn
= 0; /* ...and finishes here. */
1351 __u32 dbg_kept_tsn
= 0; /* An un-ACKed range starts here... */
1352 __u32 dbg_last_kept_tsn
= 0; /* ...and finishes here. */
1354 /* 0 : The last TSN was ACKed.
1355 * 1 : The last TSN was NOT ACKed (i.e. KEPT).
1356 * -1: We need to initialize.
1358 int dbg_prt_state
= -1;
1359 #endif /* SCTP_DEBUG */
1361 sack_ctsn
= ntohl(sack
->cum_tsn_ack
);
1363 INIT_LIST_HEAD(&tlist
);
1365 /* The while loop will skip empty transmitted queues. */
1366 while (NULL
!= (lchunk
= sctp_list_dequeue(transmitted_queue
))) {
1367 tchunk
= list_entry(lchunk
, struct sctp_chunk
,
1370 if (sctp_chunk_abandoned(tchunk
)) {
1371 /* Move the chunk to abandoned list. */
1372 sctp_insert_list(&q
->abandoned
, lchunk
);
1374 /* If this chunk has not been acked, stop
1375 * considering it as 'outstanding'.
1377 if (!tchunk
->tsn_gap_acked
) {
1378 if (tchunk
->transport
)
1379 tchunk
->transport
->flight_size
-=
1380 sctp_data_size(tchunk
);
1381 q
->outstanding_bytes
-= sctp_data_size(tchunk
);
1386 tsn
= ntohl(tchunk
->subh
.data_hdr
->tsn
);
1387 if (sctp_acked(sack
, tsn
)) {
1388 /* If this queue is the retransmit queue, the
1389 * retransmit timer has already reclaimed
1390 * the outstanding bytes for this chunk, so only
1391 * count bytes associated with a transport.
1394 /* If this chunk is being used for RTT
1395 * measurement, calculate the RTT and update
1396 * the RTO using this value.
1398 * 6.3.1 C5) Karn's algorithm: RTT measurements
1399 * MUST NOT be made using packets that were
1400 * retransmitted (and thus for which it is
1401 * ambiguous whether the reply was for the
1402 * first instance of the packet or a later
1405 if (!tchunk
->tsn_gap_acked
&&
1406 tchunk
->rtt_in_progress
) {
1407 tchunk
->rtt_in_progress
= 0;
1408 rtt
= jiffies
- tchunk
->sent_at
;
1409 sctp_transport_update_rto(transport
,
1414 /* If the chunk hasn't been marked as ACKED,
1415 * mark it and account bytes_acked if the
1416 * chunk had a valid transport (it will not
1417 * have a transport if ASCONF had deleted it
1418 * while DATA was outstanding).
1420 if (!tchunk
->tsn_gap_acked
) {
1421 tchunk
->tsn_gap_acked
= 1;
1422 bytes_acked
+= sctp_data_size(tchunk
);
1423 if (!tchunk
->transport
)
1424 migrate_bytes
+= sctp_data_size(tchunk
);
1427 if (TSN_lte(tsn
, sack_ctsn
)) {
1428 /* RFC 2960 6.3.2 Retransmission Timer Rules
1430 * R3) Whenever a SACK is received
1431 * that acknowledges the DATA chunk
1432 * with the earliest outstanding TSN
1433 * for that address, restart T3-rtx
1434 * timer for that address with its
1439 if (!tchunk
->tsn_gap_acked
) {
1441 * SFR-CACC algorithm:
1442 * 2) If the SACK contains gap acks
1443 * and the flag CHANGEOVER_ACTIVE is
1444 * set the receiver of the SACK MUST
1445 * take the following action:
1447 * B) For each TSN t being acked that
1448 * has not been acked in any SACK so
1449 * far, set cacc_saw_newack to 1 for
1450 * the destination that the TSN was
1454 sack
->num_gap_ack_blocks
&&
1455 q
->asoc
->peer
.primary_path
->cacc
.
1457 transport
->cacc
.cacc_saw_newack
1461 list_add_tail(&tchunk
->transmitted_list
,
1464 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2
1465 * M2) Each time a SACK arrives reporting
1466 * 'Stray DATA chunk(s)' record the highest TSN
1467 * reported as newly acknowledged, call this
1468 * value 'HighestTSNinSack'. A newly
1469 * acknowledged DATA chunk is one not
1470 * previously acknowledged in a SACK.
1472 * When the SCTP sender of data receives a SACK
1473 * chunk that acknowledges, for the first time,
1474 * the receipt of a DATA chunk, all the still
1475 * unacknowledged DATA chunks whose TSN is
1476 * older than that newly acknowledged DATA
1477 * chunk, are qualified as 'Stray DATA chunks'.
1479 list_add_tail(lchunk
, &tlist
);
1483 switch (dbg_prt_state
) {
1484 case 0: /* last TSN was ACKed */
1485 if (dbg_last_ack_tsn
+ 1 == tsn
) {
1486 /* This TSN belongs to the
1487 * current ACK range.
1492 if (dbg_last_ack_tsn
!= dbg_ack_tsn
) {
1493 /* Display the end of the
1496 SCTP_DEBUG_PRINTK("-%08x",
1500 /* Start a new range. */
1501 SCTP_DEBUG_PRINTK(",%08x", tsn
);
1505 case 1: /* The last TSN was NOT ACKed. */
1506 if (dbg_last_kept_tsn
!= dbg_kept_tsn
) {
1507 /* Display the end of current range. */
1508 SCTP_DEBUG_PRINTK("-%08x",
1512 SCTP_DEBUG_PRINTK("\n");
1514 /* FALL THROUGH... */
1516 /* This is the first-ever TSN we examined. */
1517 /* Start a new range of ACK-ed TSNs. */
1518 SCTP_DEBUG_PRINTK("ACKed: %08x", tsn
);
1523 dbg_last_ack_tsn
= tsn
;
1524 #endif /* SCTP_DEBUG */
1527 if (tchunk
->tsn_gap_acked
) {
1528 SCTP_DEBUG_PRINTK("%s: Receiver reneged on "
1532 tchunk
->tsn_gap_acked
= 0;
1534 if (tchunk
->transport
)
1535 bytes_acked
-= sctp_data_size(tchunk
);
1537 /* RFC 2960 6.3.2 Retransmission Timer Rules
1539 * R4) Whenever a SACK is received missing a
1540 * TSN that was previously acknowledged via a
1541 * Gap Ack Block, start T3-rtx for the
1542 * destination address to which the DATA
1543 * chunk was originally
1544 * transmitted if it is not already running.
1549 list_add_tail(lchunk
, &tlist
);
1552 /* See the above comments on ACK-ed TSNs. */
1553 switch (dbg_prt_state
) {
1555 if (dbg_last_kept_tsn
+ 1 == tsn
)
1558 if (dbg_last_kept_tsn
!= dbg_kept_tsn
)
1559 SCTP_DEBUG_PRINTK("-%08x",
1562 SCTP_DEBUG_PRINTK(",%08x", tsn
);
1567 if (dbg_last_ack_tsn
!= dbg_ack_tsn
)
1568 SCTP_DEBUG_PRINTK("-%08x",
1570 SCTP_DEBUG_PRINTK("\n");
1572 /* FALL THROUGH... */
1574 SCTP_DEBUG_PRINTK("KEPT: %08x",tsn
);
1579 dbg_last_kept_tsn
= tsn
;
1580 #endif /* SCTP_DEBUG */
1585 /* Finish off the last range, displaying its ending TSN. */
1586 switch (dbg_prt_state
) {
1588 if (dbg_last_ack_tsn
!= dbg_ack_tsn
) {
1589 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_ack_tsn
);
1591 SCTP_DEBUG_PRINTK("\n");
1596 if (dbg_last_kept_tsn
!= dbg_kept_tsn
) {
1597 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_kept_tsn
);
1599 SCTP_DEBUG_PRINTK("\n");
1602 #endif /* SCTP_DEBUG */
1605 /* We may have counted DATA that was migrated
1606 * to this transport due to DEL-IP operation.
1607 * Subtract those bytes, since the were never
1608 * send on this transport and shouldn't be
1609 * credited to this transport.
1611 bytes_acked
-= migrate_bytes
;
1613 /* 8.2. When an outstanding TSN is acknowledged,
1614 * the endpoint shall clear the error counter of
1615 * the destination transport address to which the
1616 * DATA chunk was last sent.
1617 * The association's overall error counter is
1620 transport
->error_count
= 0;
1621 transport
->asoc
->overall_error_count
= 0;
1623 /* Mark the destination transport address as
1624 * active if it is not so marked.
1626 if ((transport
->state
== SCTP_INACTIVE
) ||
1627 (transport
->state
== SCTP_UNCONFIRMED
)) {
1628 sctp_assoc_control_transport(
1632 SCTP_RECEIVED_SACK
);
1635 sctp_transport_raise_cwnd(transport
, sack_ctsn
,
1638 transport
->flight_size
-= bytes_acked
;
1639 if (transport
->flight_size
== 0)
1640 transport
->partial_bytes_acked
= 0;
1641 q
->outstanding_bytes
-= bytes_acked
+ migrate_bytes
;
1643 /* RFC 2960 6.1, sctpimpguide-06 2.15.2
1644 * When a sender is doing zero window probing, it
1645 * should not timeout the association if it continues
1646 * to receive new packets from the receiver. The
1647 * reason is that the receiver MAY keep its window
1648 * closed for an indefinite time.
1649 * A sender is doing zero window probing when the
1650 * receiver's advertised window is zero, and there is
1651 * only one data chunk in flight to the receiver.
1653 if (!q
->asoc
->peer
.rwnd
&&
1654 !list_empty(&tlist
) &&
1655 (sack_ctsn
+2 == q
->asoc
->next_tsn
)) {
1656 SCTP_DEBUG_PRINTK("%s: SACK received for zero "
1657 "window probe: %u\n",
1658 __func__
, sack_ctsn
);
1659 q
->asoc
->overall_error_count
= 0;
1660 transport
->error_count
= 0;
1664 /* RFC 2960 6.3.2 Retransmission Timer Rules
1666 * R2) Whenever all outstanding data sent to an address have
1667 * been acknowledged, turn off the T3-rtx timer of that
1670 if (!transport
->flight_size
) {
1671 if (timer_pending(&transport
->T3_rtx_timer
) &&
1672 del_timer(&transport
->T3_rtx_timer
)) {
1673 sctp_transport_put(transport
);
1675 } else if (restart_timer
) {
1676 if (!mod_timer(&transport
->T3_rtx_timer
,
1677 jiffies
+ transport
->rto
))
1678 sctp_transport_hold(transport
);
1682 list_splice(&tlist
, transmitted_queue
);
1685 /* Mark chunks as missing and consequently may get retransmitted. */
1686 static void sctp_mark_missing(struct sctp_outq
*q
,
1687 struct list_head
*transmitted_queue
,
1688 struct sctp_transport
*transport
,
1689 __u32 highest_new_tsn_in_sack
,
1690 int count_of_newacks
)
1692 struct sctp_chunk
*chunk
;
1694 char do_fast_retransmit
= 0;
1695 struct sctp_association
*asoc
= q
->asoc
;
1696 struct sctp_transport
*primary
= asoc
->peer
.primary_path
;
1698 list_for_each_entry(chunk
, transmitted_queue
, transmitted_list
) {
1700 tsn
= ntohl(chunk
->subh
.data_hdr
->tsn
);
1702 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all
1703 * 'Unacknowledged TSN's', if the TSN number of an
1704 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack'
1705 * value, increment the 'TSN.Missing.Report' count on that
1706 * chunk if it has NOT been fast retransmitted or marked for
1707 * fast retransmit already.
1709 if (chunk
->fast_retransmit
== SCTP_CAN_FRTX
&&
1710 !chunk
->tsn_gap_acked
&&
1711 TSN_lt(tsn
, highest_new_tsn_in_sack
)) {
1713 /* SFR-CACC may require us to skip marking
1714 * this chunk as missing.
1716 if (!transport
|| !sctp_cacc_skip(primary
, transport
,
1717 count_of_newacks
, tsn
)) {
1718 chunk
->tsn_missing_report
++;
1721 "%s: TSN 0x%x missing counter: %d\n",
1723 chunk
->tsn_missing_report
);
1727 * M4) If any DATA chunk is found to have a
1728 * 'TSN.Missing.Report'
1729 * value larger than or equal to 3, mark that chunk for
1730 * retransmission and start the fast retransmit procedure.
1733 if (chunk
->tsn_missing_report
>= 3) {
1734 chunk
->fast_retransmit
= SCTP_NEED_FRTX
;
1735 do_fast_retransmit
= 1;
1740 if (do_fast_retransmit
)
1741 sctp_retransmit(q
, transport
, SCTP_RTXR_FAST_RTX
);
1743 SCTP_DEBUG_PRINTK("%s: transport: %p, cwnd: %d, "
1744 "ssthresh: %d, flight_size: %d, pba: %d\n",
1745 __func__
, transport
, transport
->cwnd
,
1746 transport
->ssthresh
, transport
->flight_size
,
1747 transport
->partial_bytes_acked
);
1751 /* Is the given TSN acked by this packet? */
1752 static int sctp_acked(struct sctp_sackhdr
*sack
, __u32 tsn
)
1755 sctp_sack_variable_t
*frags
;
1757 __u32 ctsn
= ntohl(sack
->cum_tsn_ack
);
1759 if (TSN_lte(tsn
, ctsn
))
1762 /* 3.3.4 Selective Acknowledgement (SACK) (3):
1765 * These fields contain the Gap Ack Blocks. They are repeated
1766 * for each Gap Ack Block up to the number of Gap Ack Blocks
1767 * defined in the Number of Gap Ack Blocks field. All DATA
1768 * chunks with TSNs greater than or equal to (Cumulative TSN
1769 * Ack + Gap Ack Block Start) and less than or equal to
1770 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack
1771 * Block are assumed to have been received correctly.
1774 frags
= sack
->variable
;
1776 for (i
= 0; i
< ntohs(sack
->num_gap_ack_blocks
); ++i
) {
1777 if (TSN_lte(ntohs(frags
[i
].gab
.start
), gap
) &&
1778 TSN_lte(gap
, ntohs(frags
[i
].gab
.end
)))
1787 static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip
*skiplist
,
1788 int nskips
, __be16 stream
)
1792 for (i
= 0; i
< nskips
; i
++) {
1793 if (skiplist
[i
].stream
== stream
)
1799 /* Create and add a fwdtsn chunk to the outq's control queue if needed. */
1800 static void sctp_generate_fwdtsn(struct sctp_outq
*q
, __u32 ctsn
)
1802 struct sctp_association
*asoc
= q
->asoc
;
1803 struct sctp_chunk
*ftsn_chunk
= NULL
;
1804 struct sctp_fwdtsn_skip ftsn_skip_arr
[10];
1808 struct sctp_chunk
*chunk
;
1809 struct list_head
*lchunk
, *temp
;
1811 if (!asoc
->peer
.prsctp_capable
)
1814 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the
1817 * If (Advanced.Peer.Ack.Point < SackCumAck), then update
1818 * Advanced.Peer.Ack.Point to be equal to SackCumAck.
1820 if (TSN_lt(asoc
->adv_peer_ack_point
, ctsn
))
1821 asoc
->adv_peer_ack_point
= ctsn
;
1823 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point"
1824 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as
1825 * the chunk next in the out-queue space is marked as "abandoned" as
1826 * shown in the following example:
1828 * Assuming that a SACK arrived with the Cumulative TSN ACK 102
1829 * and the Advanced.Peer.Ack.Point is updated to this value:
1831 * out-queue at the end of ==> out-queue after Adv.Ack.Point
1832 * normal SACK processing local advancement
1834 * Adv.Ack.Pt-> 102 acked 102 acked
1835 * 103 abandoned 103 abandoned
1836 * 104 abandoned Adv.Ack.P-> 104 abandoned
1838 * 106 acked 106 acked
1841 * In this example, the data sender successfully advanced the
1842 * "Advanced.Peer.Ack.Point" from 102 to 104 locally.
1844 list_for_each_safe(lchunk
, temp
, &q
->abandoned
) {
1845 chunk
= list_entry(lchunk
, struct sctp_chunk
,
1847 tsn
= ntohl(chunk
->subh
.data_hdr
->tsn
);
1849 /* Remove any chunks in the abandoned queue that are acked by
1852 if (TSN_lte(tsn
, ctsn
)) {
1853 list_del_init(lchunk
);
1854 sctp_chunk_free(chunk
);
1856 if (TSN_lte(tsn
, asoc
->adv_peer_ack_point
+1)) {
1857 asoc
->adv_peer_ack_point
= tsn
;
1858 if (chunk
->chunk_hdr
->flags
&
1859 SCTP_DATA_UNORDERED
)
1861 skip_pos
= sctp_get_skip_pos(&ftsn_skip_arr
[0],
1863 chunk
->subh
.data_hdr
->stream
);
1864 ftsn_skip_arr
[skip_pos
].stream
=
1865 chunk
->subh
.data_hdr
->stream
;
1866 ftsn_skip_arr
[skip_pos
].ssn
=
1867 chunk
->subh
.data_hdr
->ssn
;
1868 if (skip_pos
== nskips
)
1877 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point"
1878 * is greater than the Cumulative TSN ACK carried in the received
1879 * SACK, the data sender MUST send the data receiver a FORWARD TSN
1880 * chunk containing the latest value of the
1881 * "Advanced.Peer.Ack.Point".
1883 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD
1884 * list each stream and sequence number in the forwarded TSN. This
1885 * information will enable the receiver to easily find any
1886 * stranded TSN's waiting on stream reorder queues. Each stream
1887 * SHOULD only be reported once; this means that if multiple
1888 * abandoned messages occur in the same stream then only the
1889 * highest abandoned stream sequence number is reported. If the
1890 * total size of the FORWARD TSN does NOT fit in a single MTU then
1891 * the sender of the FORWARD TSN SHOULD lower the
1892 * Advanced.Peer.Ack.Point to the last TSN that will fit in a
1895 if (asoc
->adv_peer_ack_point
> ctsn
)
1896 ftsn_chunk
= sctp_make_fwdtsn(asoc
, asoc
->adv_peer_ack_point
,
1897 nskips
, &ftsn_skip_arr
[0]);
1900 list_add_tail(&ftsn_chunk
->list
, &q
->control_chunk_list
);
1901 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS
);