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 <net/sock.h> /* For skb_set_owner_w */
55 #include <net/sctp/sctp.h>
56 #include <net/sctp/sm.h>
58 /* Declare internal functions here. */
59 static int sctp_acked(struct sctp_sackhdr
*sack
, __u32 tsn
);
60 static void sctp_check_transmitted(struct sctp_outq
*q
,
61 struct list_head
*transmitted_queue
,
62 struct sctp_transport
*transport
,
63 struct sctp_sackhdr
*sack
,
64 __u32 highest_new_tsn
);
66 static void sctp_mark_missing(struct sctp_outq
*q
,
67 struct list_head
*transmitted_queue
,
68 struct sctp_transport
*transport
,
69 __u32 highest_new_tsn
,
70 int count_of_newacks
);
72 static void sctp_generate_fwdtsn(struct sctp_outq
*q
, __u32 sack_ctsn
);
74 static int sctp_outq_flush(struct sctp_outq
*q
, int rtx_timeout
);
76 /* Add data to the front of the queue. */
77 static inline void sctp_outq_head_data(struct sctp_outq
*q
,
78 struct sctp_chunk
*ch
)
80 list_add(&ch
->list
, &q
->out_chunk_list
);
81 q
->out_qlen
+= ch
->skb
->len
;
85 /* Take data from the front of the queue. */
86 static inline struct sctp_chunk
*sctp_outq_dequeue_data(struct sctp_outq
*q
)
88 struct sctp_chunk
*ch
= NULL
;
90 if (!list_empty(&q
->out_chunk_list
)) {
91 struct list_head
*entry
= q
->out_chunk_list
.next
;
93 ch
= list_entry(entry
, struct sctp_chunk
, list
);
95 q
->out_qlen
-= ch
->skb
->len
;
99 /* Add data chunk to the end of the queue. */
100 static inline void sctp_outq_tail_data(struct sctp_outq
*q
,
101 struct sctp_chunk
*ch
)
103 list_add_tail(&ch
->list
, &q
->out_chunk_list
);
104 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 /* Initialize an existing sctp_outq. This does the boring stuff.
201 * You still need to define handlers if you really want to DO
202 * something with this structure...
204 void sctp_outq_init(struct sctp_association
*asoc
, struct sctp_outq
*q
)
207 INIT_LIST_HEAD(&q
->out_chunk_list
);
208 INIT_LIST_HEAD(&q
->control_chunk_list
);
209 INIT_LIST_HEAD(&q
->retransmit
);
210 INIT_LIST_HEAD(&q
->sacked
);
211 INIT_LIST_HEAD(&q
->abandoned
);
214 q
->outstanding_bytes
= 0;
222 /* Free the outqueue structure and any related pending chunks.
224 void sctp_outq_teardown(struct sctp_outq
*q
)
226 struct sctp_transport
*transport
;
227 struct list_head
*lchunk
, *temp
;
228 struct sctp_chunk
*chunk
, *tmp
;
230 /* Throw away unacknowledged chunks. */
231 list_for_each_entry(transport
, &q
->asoc
->peer
.transport_addr_list
,
233 while ((lchunk
= sctp_list_dequeue(&transport
->transmitted
)) != NULL
) {
234 chunk
= list_entry(lchunk
, struct sctp_chunk
,
236 /* Mark as part of a failed message. */
237 sctp_chunk_fail(chunk
, q
->error
);
238 sctp_chunk_free(chunk
);
242 /* Throw away chunks that have been gap ACKed. */
243 list_for_each_safe(lchunk
, temp
, &q
->sacked
) {
244 list_del_init(lchunk
);
245 chunk
= list_entry(lchunk
, struct sctp_chunk
,
247 sctp_chunk_fail(chunk
, q
->error
);
248 sctp_chunk_free(chunk
);
251 /* Throw away any chunks in the retransmit queue. */
252 list_for_each_safe(lchunk
, temp
, &q
->retransmit
) {
253 list_del_init(lchunk
);
254 chunk
= list_entry(lchunk
, struct sctp_chunk
,
256 sctp_chunk_fail(chunk
, q
->error
);
257 sctp_chunk_free(chunk
);
260 /* Throw away any chunks that are in the abandoned queue. */
261 list_for_each_safe(lchunk
, temp
, &q
->abandoned
) {
262 list_del_init(lchunk
);
263 chunk
= list_entry(lchunk
, struct sctp_chunk
,
265 sctp_chunk_fail(chunk
, q
->error
);
266 sctp_chunk_free(chunk
);
269 /* Throw away any leftover data chunks. */
270 while ((chunk
= sctp_outq_dequeue_data(q
)) != NULL
) {
272 /* Mark as send failure. */
273 sctp_chunk_fail(chunk
, q
->error
);
274 sctp_chunk_free(chunk
);
279 /* Throw away any leftover control chunks. */
280 list_for_each_entry_safe(chunk
, tmp
, &q
->control_chunk_list
, list
) {
281 list_del_init(&chunk
->list
);
282 sctp_chunk_free(chunk
);
286 /* Free the outqueue structure and any related pending chunks. */
287 void sctp_outq_free(struct sctp_outq
*q
)
289 /* Throw away leftover chunks. */
290 sctp_outq_teardown(q
);
292 /* If we were kmalloc()'d, free the memory. */
297 /* Put a new chunk in an sctp_outq. */
298 int sctp_outq_tail(struct sctp_outq
*q
, struct sctp_chunk
*chunk
)
302 SCTP_DEBUG_PRINTK("sctp_outq_tail(%p, %p[%s])\n",
303 q
, chunk
, chunk
&& chunk
->chunk_hdr
?
304 sctp_cname(SCTP_ST_CHUNK(chunk
->chunk_hdr
->type
))
307 /* If it is data, queue it up, otherwise, send it
310 if (SCTP_CID_DATA
== chunk
->chunk_hdr
->type
) {
311 /* Is it OK to queue data chunks? */
312 /* From 9. Termination of Association
314 * When either endpoint performs a shutdown, the
315 * association on each peer will stop accepting new
316 * data from its user and only deliver data in queue
317 * at the time of sending or receiving the SHUTDOWN
320 switch (q
->asoc
->state
) {
321 case SCTP_STATE_EMPTY
:
322 case SCTP_STATE_CLOSED
:
323 case SCTP_STATE_SHUTDOWN_PENDING
:
324 case SCTP_STATE_SHUTDOWN_SENT
:
325 case SCTP_STATE_SHUTDOWN_RECEIVED
:
326 case SCTP_STATE_SHUTDOWN_ACK_SENT
:
327 /* Cannot send after transport endpoint shutdown */
332 SCTP_DEBUG_PRINTK("outqueueing (%p, %p[%s])\n",
333 q
, chunk
, chunk
&& chunk
->chunk_hdr
?
334 sctp_cname(SCTP_ST_CHUNK(chunk
->chunk_hdr
->type
))
337 sctp_outq_tail_data(q
, chunk
);
338 if (chunk
->chunk_hdr
->flags
& SCTP_DATA_UNORDERED
)
339 SCTP_INC_STATS(SCTP_MIB_OUTUNORDERCHUNKS
);
341 SCTP_INC_STATS(SCTP_MIB_OUTORDERCHUNKS
);
346 list_add_tail(&chunk
->list
, &q
->control_chunk_list
);
347 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS
);
354 error
= sctp_outq_flush(q
, 0);
359 /* Insert a chunk into the sorted list based on the TSNs. The retransmit list
360 * and the abandoned list are in ascending order.
362 static void sctp_insert_list(struct list_head
*head
, struct list_head
*new)
364 struct list_head
*pos
;
365 struct sctp_chunk
*nchunk
, *lchunk
;
369 nchunk
= list_entry(new, struct sctp_chunk
, transmitted_list
);
370 ntsn
= ntohl(nchunk
->subh
.data_hdr
->tsn
);
372 list_for_each(pos
, head
) {
373 lchunk
= list_entry(pos
, struct sctp_chunk
, transmitted_list
);
374 ltsn
= ntohl(lchunk
->subh
.data_hdr
->tsn
);
375 if (TSN_lt(ntsn
, ltsn
)) {
376 list_add(new, pos
->prev
);
382 list_add_tail(new, head
);
385 /* Mark all the eligible packets on a transport for retransmission. */
386 void sctp_retransmit_mark(struct sctp_outq
*q
,
387 struct sctp_transport
*transport
,
390 struct list_head
*lchunk
, *ltemp
;
391 struct sctp_chunk
*chunk
;
393 /* Walk through the specified transmitted queue. */
394 list_for_each_safe(lchunk
, ltemp
, &transport
->transmitted
) {
395 chunk
= list_entry(lchunk
, struct sctp_chunk
,
398 /* If the chunk is abandoned, move it to abandoned list. */
399 if (sctp_chunk_abandoned(chunk
)) {
400 list_del_init(lchunk
);
401 sctp_insert_list(&q
->abandoned
, lchunk
);
403 /* If this chunk has not been previousely acked,
404 * stop considering it 'outstanding'. Our peer
405 * will most likely never see it since it will
406 * not be retransmitted
408 if (!chunk
->tsn_gap_acked
) {
409 if (chunk
->transport
)
410 chunk
->transport
->flight_size
-=
411 sctp_data_size(chunk
);
412 q
->outstanding_bytes
-= sctp_data_size(chunk
);
413 q
->asoc
->peer
.rwnd
+= (sctp_data_size(chunk
) +
414 sizeof(struct sk_buff
));
419 /* If we are doing retransmission due to a timeout or pmtu
420 * discovery, only the chunks that are not yet acked should
421 * be added to the retransmit queue.
423 if ((reason
== SCTP_RTXR_FAST_RTX
&&
424 (chunk
->fast_retransmit
== SCTP_NEED_FRTX
)) ||
425 (reason
!= SCTP_RTXR_FAST_RTX
&& !chunk
->tsn_gap_acked
)) {
426 /* RFC 2960 6.2.1 Processing a Received SACK
428 * C) Any time a DATA chunk is marked for
429 * retransmission (via either T3-rtx timer expiration
430 * (Section 6.3.3) or via fast retransmit
431 * (Section 7.2.4)), add the data size of those
432 * chunks to the rwnd.
434 q
->asoc
->peer
.rwnd
+= (sctp_data_size(chunk
) +
435 sizeof(struct sk_buff
));
436 q
->outstanding_bytes
-= sctp_data_size(chunk
);
437 if (chunk
->transport
)
438 transport
->flight_size
-= sctp_data_size(chunk
);
440 /* sctpimpguide-05 Section 2.8.2
441 * M5) If a T3-rtx timer expires, the
442 * 'TSN.Missing.Report' of all affected TSNs is set
445 chunk
->tsn_missing_report
= 0;
447 /* If a chunk that is being used for RTT measurement
448 * has to be retransmitted, we cannot use this chunk
449 * anymore for RTT measurements. Reset rto_pending so
450 * that a new RTT measurement is started when a new
451 * data chunk is sent.
453 if (chunk
->rtt_in_progress
) {
454 chunk
->rtt_in_progress
= 0;
455 transport
->rto_pending
= 0;
458 /* Move the chunk to the retransmit queue. The chunks
459 * on the retransmit queue are always kept in order.
461 list_del_init(lchunk
);
462 sctp_insert_list(&q
->retransmit
, lchunk
);
466 SCTP_DEBUG_PRINTK("%s: transport: %p, reason: %d, "
467 "cwnd: %d, ssthresh: %d, flight_size: %d, "
468 "pba: %d\n", __func__
,
470 transport
->cwnd
, transport
->ssthresh
,
471 transport
->flight_size
,
472 transport
->partial_bytes_acked
);
476 /* Mark all the eligible packets on a transport for retransmission and force
479 void sctp_retransmit(struct sctp_outq
*q
, struct sctp_transport
*transport
,
480 sctp_retransmit_reason_t reason
)
485 case SCTP_RTXR_T3_RTX
:
486 SCTP_INC_STATS(SCTP_MIB_T3_RETRANSMITS
);
487 sctp_transport_lower_cwnd(transport
, SCTP_LOWER_CWND_T3_RTX
);
488 /* Update the retran path if the T3-rtx timer has expired for
489 * the current retran path.
491 if (transport
== transport
->asoc
->peer
.retran_path
)
492 sctp_assoc_update_retran_path(transport
->asoc
);
493 transport
->asoc
->rtx_data_chunks
+=
494 transport
->asoc
->unack_data
;
496 case SCTP_RTXR_FAST_RTX
:
497 SCTP_INC_STATS(SCTP_MIB_FAST_RETRANSMITS
);
498 sctp_transport_lower_cwnd(transport
, SCTP_LOWER_CWND_FAST_RTX
);
501 case SCTP_RTXR_PMTUD
:
502 SCTP_INC_STATS(SCTP_MIB_PMTUD_RETRANSMITS
);
504 case SCTP_RTXR_T1_RTX
:
505 SCTP_INC_STATS(SCTP_MIB_T1_RETRANSMITS
);
506 transport
->asoc
->init_retries
++;
512 sctp_retransmit_mark(q
, transport
, reason
);
514 /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination,
515 * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by
516 * following the procedures outlined in C1 - C5.
518 if (reason
== SCTP_RTXR_T3_RTX
)
519 sctp_generate_fwdtsn(q
, q
->asoc
->ctsn_ack_point
);
521 /* Flush the queues only on timeout, since fast_rtx is only
522 * triggered during sack processing and the queue
523 * will be flushed at the end.
525 if (reason
!= SCTP_RTXR_FAST_RTX
)
526 error
= sctp_outq_flush(q
, /* rtx_timeout */ 1);
529 q
->asoc
->base
.sk
->sk_err
= -error
;
533 * Transmit DATA chunks on the retransmit queue. Upon return from
534 * sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which
535 * need to be transmitted by the caller.
536 * We assume that pkt->transport has already been set.
538 * The return value is a normal kernel error return value.
540 static int sctp_outq_flush_rtx(struct sctp_outq
*q
, struct sctp_packet
*pkt
,
541 int rtx_timeout
, int *start_timer
)
543 struct list_head
*lqueue
;
544 struct sctp_transport
*transport
= pkt
->transport
;
546 struct sctp_chunk
*chunk
, *chunk1
;
547 struct sctp_association
*asoc
;
554 lqueue
= &q
->retransmit
;
555 fast_rtx
= q
->fast_rtx
;
557 /* This loop handles time-out retransmissions, fast retransmissions,
558 * and retransmissions due to opening of whindow.
560 * RFC 2960 6.3.3 Handle T3-rtx Expiration
562 * E3) Determine how many of the earliest (i.e., lowest TSN)
563 * outstanding DATA chunks for the address for which the
564 * T3-rtx has expired will fit into a single packet, subject
565 * to the MTU constraint for the path corresponding to the
566 * destination transport address to which the retransmission
567 * is being sent (this may be different from the address for
568 * which the timer expires [see Section 6.4]). Call this value
569 * K. Bundle and retransmit those K DATA chunks in a single
570 * packet to the destination endpoint.
572 * [Just to be painfully clear, if we are retransmitting
573 * because a timeout just happened, we should send only ONE
574 * packet of retransmitted data.]
576 * For fast retransmissions we also send only ONE packet. However,
577 * if we are just flushing the queue due to open window, we'll
578 * try to send as much as possible.
580 list_for_each_entry_safe(chunk
, chunk1
, lqueue
, transmitted_list
) {
582 /* Make sure that Gap Acked TSNs are not retransmitted. A
583 * simple approach is just to move such TSNs out of the
584 * way and into a 'transmitted' queue and skip to the
587 if (chunk
->tsn_gap_acked
) {
588 list_del(&chunk
->transmitted_list
);
589 list_add_tail(&chunk
->transmitted_list
,
590 &transport
->transmitted
);
594 /* If we are doing fast retransmit, ignore non-fast_rtransmit
597 if (fast_rtx
&& !chunk
->fast_retransmit
)
600 /* Attempt to append this chunk to the packet. */
601 status
= sctp_packet_append_chunk(pkt
, chunk
);
604 case SCTP_XMIT_PMTU_FULL
:
605 /* Send this packet. */
606 error
= sctp_packet_transmit(pkt
);
608 /* If we are retransmitting, we should only
609 * send a single packet.
611 if (rtx_timeout
|| fast_rtx
)
614 /* Bundle next chunk in the next round. */
617 case SCTP_XMIT_RWND_FULL
:
618 /* Send this packet. */
619 error
= sctp_packet_transmit(pkt
);
621 /* Stop sending DATA as there is no more room
627 case SCTP_XMIT_NAGLE_DELAY
:
628 /* Send this packet. */
629 error
= sctp_packet_transmit(pkt
);
631 /* Stop sending DATA because of nagle delay. */
636 /* The append was successful, so add this chunk to
637 * the transmitted list.
639 list_del(&chunk
->transmitted_list
);
640 list_add_tail(&chunk
->transmitted_list
,
641 &transport
->transmitted
);
643 /* Mark the chunk as ineligible for fast retransmit
644 * after it is retransmitted.
646 if (chunk
->fast_retransmit
== SCTP_NEED_FRTX
)
647 chunk
->fast_retransmit
= SCTP_DONT_FRTX
;
649 /* Force start T3-rtx timer when fast retransmitting
650 * the earliest outstanding TSN
652 if (!timer
&& fast_rtx
&&
653 ntohl(chunk
->subh
.data_hdr
->tsn
) ==
654 asoc
->ctsn_ack_point
+ 1)
661 /* Set the timer if there were no errors */
662 if (!error
&& !timer
)
669 /* If we are here due to a retransmit timeout or a fast
670 * retransmit and if there are any chunks left in the retransmit
671 * queue that could not fit in the PMTU sized packet, they need
672 * to be marked as ineligible for a subsequent fast retransmit.
674 if (rtx_timeout
|| fast_rtx
) {
675 list_for_each_entry(chunk1
, lqueue
, transmitted_list
) {
676 if (chunk1
->fast_retransmit
== SCTP_NEED_FRTX
)
677 chunk1
->fast_retransmit
= SCTP_DONT_FRTX
;
681 *start_timer
= timer
;
683 /* Clear fast retransmit hint */
690 /* Cork the outqueue so queued chunks are really queued. */
691 int sctp_outq_uncork(struct sctp_outq
*q
)
696 error
= sctp_outq_flush(q
, 0);
702 * Try to flush an outqueue.
704 * Description: Send everything in q which we legally can, subject to
705 * congestion limitations.
706 * * Note: This function can be called from multiple contexts so appropriate
707 * locking concerns must be made. Today we use the sock lock to protect
710 static int sctp_outq_flush(struct sctp_outq
*q
, int rtx_timeout
)
712 struct sctp_packet
*packet
;
713 struct sctp_packet singleton
;
714 struct sctp_association
*asoc
= q
->asoc
;
715 __u16 sport
= asoc
->base
.bind_addr
.port
;
716 __u16 dport
= asoc
->peer
.port
;
717 __u32 vtag
= asoc
->peer
.i
.init_tag
;
718 struct sctp_transport
*transport
= NULL
;
719 struct sctp_transport
*new_transport
;
720 struct sctp_chunk
*chunk
, *tmp
;
726 /* These transports have chunks to send. */
727 struct list_head transport_list
;
728 struct list_head
*ltransport
;
730 INIT_LIST_HEAD(&transport_list
);
736 * When bundling control chunks with DATA chunks, an
737 * endpoint MUST place control chunks first in the outbound
738 * SCTP packet. The transmitter MUST transmit DATA chunks
739 * within a SCTP packet in increasing order of TSN.
743 list_for_each_entry_safe(chunk
, tmp
, &q
->control_chunk_list
, list
) {
744 list_del_init(&chunk
->list
);
746 /* Pick the right transport to use. */
747 new_transport
= chunk
->transport
;
749 if (!new_transport
) {
751 * If we have a prior transport pointer, see if
752 * the destination address of the chunk
753 * matches the destination address of the
754 * current transport. If not a match, then
755 * try to look up the transport with a given
756 * destination address. We do this because
757 * after processing ASCONFs, we may have new
758 * transports created.
761 sctp_cmp_addr_exact(&chunk
->dest
,
763 new_transport
= transport
;
765 new_transport
= sctp_assoc_lookup_paddr(asoc
,
768 /* if we still don't have a new transport, then
769 * use the current active path.
772 new_transport
= asoc
->peer
.active_path
;
773 } else if ((new_transport
->state
== SCTP_INACTIVE
) ||
774 (new_transport
->state
== SCTP_UNCONFIRMED
)) {
775 /* If the chunk is Heartbeat or Heartbeat Ack,
776 * send it to chunk->transport, even if it's
779 * 3.3.6 Heartbeat Acknowledgement:
781 * A HEARTBEAT ACK is always sent to the source IP
782 * address of the IP datagram containing the
783 * HEARTBEAT chunk to which this ack is responding.
786 * ASCONF_ACKs also must be sent to the source.
788 if (chunk
->chunk_hdr
->type
!= SCTP_CID_HEARTBEAT
&&
789 chunk
->chunk_hdr
->type
!= SCTP_CID_HEARTBEAT_ACK
&&
790 chunk
->chunk_hdr
->type
!= SCTP_CID_ASCONF_ACK
)
791 new_transport
= asoc
->peer
.active_path
;
794 /* Are we switching transports?
795 * Take care of transport locks.
797 if (new_transport
!= transport
) {
798 transport
= new_transport
;
799 if (list_empty(&transport
->send_ready
)) {
800 list_add_tail(&transport
->send_ready
,
803 packet
= &transport
->packet
;
804 sctp_packet_config(packet
, vtag
,
805 asoc
->peer
.ecn_capable
);
808 switch (chunk
->chunk_hdr
->type
) {
812 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN
813 * COMPLETE with any other chunks. [Send them immediately.]
816 case SCTP_CID_INIT_ACK
:
817 case SCTP_CID_SHUTDOWN_COMPLETE
:
818 sctp_packet_init(&singleton
, transport
, sport
, dport
);
819 sctp_packet_config(&singleton
, vtag
, 0);
820 sctp_packet_append_chunk(&singleton
, chunk
);
821 error
= sctp_packet_transmit(&singleton
);
827 if (sctp_test_T_bit(chunk
)) {
828 packet
->vtag
= asoc
->c
.my_vtag
;
830 /* The following chunks are "response" chunks, i.e.
831 * they are generated in response to something we
832 * received. If we are sending these, then we can
833 * send only 1 packet containing these chunks.
835 case SCTP_CID_HEARTBEAT_ACK
:
836 case SCTP_CID_SHUTDOWN_ACK
:
837 case SCTP_CID_COOKIE_ACK
:
838 case SCTP_CID_COOKIE_ECHO
:
840 case SCTP_CID_ECN_CWR
:
841 case SCTP_CID_ASCONF_ACK
:
846 case SCTP_CID_HEARTBEAT
:
847 case SCTP_CID_SHUTDOWN
:
848 case SCTP_CID_ECN_ECNE
:
849 case SCTP_CID_ASCONF
:
850 case SCTP_CID_FWD_TSN
:
851 status
= sctp_packet_transmit_chunk(packet
, chunk
,
853 if (status
!= SCTP_XMIT_OK
) {
854 /* put the chunk back */
855 list_add(&chunk
->list
, &q
->control_chunk_list
);
860 /* We built a chunk with an illegal type! */
865 /* Is it OK to send data chunks? */
866 switch (asoc
->state
) {
867 case SCTP_STATE_COOKIE_ECHOED
:
868 /* Only allow bundling when this packet has a COOKIE-ECHO
871 if (!packet
|| !packet
->has_cookie_echo
)
875 case SCTP_STATE_ESTABLISHED
:
876 case SCTP_STATE_SHUTDOWN_PENDING
:
877 case SCTP_STATE_SHUTDOWN_RECEIVED
:
879 * RFC 2960 6.1 Transmission of DATA Chunks
881 * C) When the time comes for the sender to transmit,
882 * before sending new DATA chunks, the sender MUST
883 * first transmit any outstanding DATA chunks which
884 * are marked for retransmission (limited by the
887 if (!list_empty(&q
->retransmit
)) {
888 if (transport
== asoc
->peer
.retran_path
)
891 /* Switch transports & prepare the packet. */
893 transport
= asoc
->peer
.retran_path
;
895 if (list_empty(&transport
->send_ready
)) {
896 list_add_tail(&transport
->send_ready
,
900 packet
= &transport
->packet
;
901 sctp_packet_config(packet
, vtag
,
902 asoc
->peer
.ecn_capable
);
904 error
= sctp_outq_flush_rtx(q
, packet
,
905 rtx_timeout
, &start_timer
);
908 sctp_transport_reset_timers(transport
,
911 /* This can happen on COOKIE-ECHO resend. Only
912 * one chunk can get bundled with a COOKIE-ECHO.
914 if (packet
->has_cookie_echo
)
917 /* Don't send new data if there is still data
918 * waiting to retransmit.
920 if (!list_empty(&q
->retransmit
))
924 /* Finally, transmit new packets. */
925 while ((chunk
= sctp_outq_dequeue_data(q
)) != NULL
) {
926 /* RFC 2960 6.5 Every DATA chunk MUST carry a valid
929 if (chunk
->sinfo
.sinfo_stream
>=
930 asoc
->c
.sinit_num_ostreams
) {
932 /* Mark as failed send. */
933 sctp_chunk_fail(chunk
, SCTP_ERROR_INV_STRM
);
934 sctp_chunk_free(chunk
);
938 /* Has this chunk expired? */
939 if (sctp_chunk_abandoned(chunk
)) {
940 sctp_chunk_fail(chunk
, 0);
941 sctp_chunk_free(chunk
);
945 /* If there is a specified transport, use it.
946 * Otherwise, we want to use the active path.
948 new_transport
= chunk
->transport
;
949 if (!new_transport
||
950 ((new_transport
->state
== SCTP_INACTIVE
) ||
951 (new_transport
->state
== SCTP_UNCONFIRMED
)))
952 new_transport
= asoc
->peer
.active_path
;
954 /* Change packets if necessary. */
955 if (new_transport
!= transport
) {
956 transport
= new_transport
;
958 /* Schedule to have this transport's
961 if (list_empty(&transport
->send_ready
)) {
962 list_add_tail(&transport
->send_ready
,
966 packet
= &transport
->packet
;
967 sctp_packet_config(packet
, vtag
,
968 asoc
->peer
.ecn_capable
);
971 SCTP_DEBUG_PRINTK("sctp_outq_flush(%p, %p[%s]), ",
973 chunk
&& chunk
->chunk_hdr
?
974 sctp_cname(SCTP_ST_CHUNK(
975 chunk
->chunk_hdr
->type
))
978 SCTP_DEBUG_PRINTK("TX TSN 0x%x skb->head "
979 "%p skb->users %d.\n",
980 ntohl(chunk
->subh
.data_hdr
->tsn
),
981 chunk
->skb
?chunk
->skb
->head
: NULL
,
983 atomic_read(&chunk
->skb
->users
) : -1);
985 /* Add the chunk to the packet. */
986 status
= sctp_packet_transmit_chunk(packet
, chunk
, 0);
989 case SCTP_XMIT_PMTU_FULL
:
990 case SCTP_XMIT_RWND_FULL
:
991 case SCTP_XMIT_NAGLE_DELAY
:
992 /* We could not append this chunk, so put
993 * the chunk back on the output queue.
995 SCTP_DEBUG_PRINTK("sctp_outq_flush: could "
996 "not transmit TSN: 0x%x, status: %d\n",
997 ntohl(chunk
->subh
.data_hdr
->tsn
),
999 sctp_outq_head_data(q
, chunk
);
1000 goto sctp_flush_out
;
1010 /* BUG: We assume that the sctp_packet_transmit()
1011 * call below will succeed all the time and add the
1012 * chunk to the transmitted list and restart the
1014 * It is possible that the call can fail under OOM
1017 * Is this really a problem? Won't this behave
1020 list_add_tail(&chunk
->transmitted_list
,
1021 &transport
->transmitted
);
1023 sctp_transport_reset_timers(transport
, 0);
1027 /* Only let one DATA chunk get bundled with a
1028 * COOKIE-ECHO chunk.
1030 if (packet
->has_cookie_echo
)
1031 goto sctp_flush_out
;
1042 /* Before returning, examine all the transports touched in
1043 * this call. Right now, we bluntly force clear all the
1044 * transports. Things might change after we implement Nagle.
1045 * But such an examination is still required.
1049 while ((ltransport
= sctp_list_dequeue(&transport_list
)) != NULL
) {
1050 struct sctp_transport
*t
= list_entry(ltransport
,
1051 struct sctp_transport
,
1053 packet
= &t
->packet
;
1054 if (!sctp_packet_empty(packet
))
1055 error
= sctp_packet_transmit(packet
);
1061 /* Update unack_data based on the incoming SACK chunk */
1062 static void sctp_sack_update_unack_data(struct sctp_association
*assoc
,
1063 struct sctp_sackhdr
*sack
)
1065 sctp_sack_variable_t
*frags
;
1069 unack_data
= assoc
->next_tsn
- assoc
->ctsn_ack_point
- 1;
1071 frags
= sack
->variable
;
1072 for (i
= 0; i
< ntohs(sack
->num_gap_ack_blocks
); i
++) {
1073 unack_data
-= ((ntohs(frags
[i
].gab
.end
) -
1074 ntohs(frags
[i
].gab
.start
) + 1));
1077 assoc
->unack_data
= unack_data
;
1080 /* Return the highest new tsn that is acknowledged by the given SACK chunk. */
1081 static __u32
sctp_highest_new_tsn(struct sctp_sackhdr
*sack
,
1082 struct sctp_association
*asoc
)
1084 struct sctp_transport
*transport
;
1085 struct sctp_chunk
*chunk
;
1086 __u32 highest_new_tsn
, tsn
;
1087 struct list_head
*transport_list
= &asoc
->peer
.transport_addr_list
;
1089 highest_new_tsn
= ntohl(sack
->cum_tsn_ack
);
1091 list_for_each_entry(transport
, transport_list
, transports
) {
1092 list_for_each_entry(chunk
, &transport
->transmitted
,
1094 tsn
= ntohl(chunk
->subh
.data_hdr
->tsn
);
1096 if (!chunk
->tsn_gap_acked
&&
1097 TSN_lt(highest_new_tsn
, tsn
) &&
1098 sctp_acked(sack
, tsn
))
1099 highest_new_tsn
= tsn
;
1103 return highest_new_tsn
;
1106 /* This is where we REALLY process a SACK.
1108 * Process the SACK against the outqueue. Mostly, this just frees
1109 * things off the transmitted queue.
1111 int sctp_outq_sack(struct sctp_outq
*q
, struct sctp_sackhdr
*sack
)
1113 struct sctp_association
*asoc
= q
->asoc
;
1114 struct sctp_transport
*transport
;
1115 struct sctp_chunk
*tchunk
= NULL
;
1116 struct list_head
*lchunk
, *transport_list
, *temp
;
1117 sctp_sack_variable_t
*frags
= sack
->variable
;
1118 __u32 sack_ctsn
, ctsn
, tsn
;
1119 __u32 highest_tsn
, highest_new_tsn
;
1121 unsigned outstanding
;
1122 struct sctp_transport
*primary
= asoc
->peer
.primary_path
;
1123 int count_of_newacks
= 0;
1126 /* Grab the association's destination address list. */
1127 transport_list
= &asoc
->peer
.transport_addr_list
;
1129 sack_ctsn
= ntohl(sack
->cum_tsn_ack
);
1130 gap_ack_blocks
= ntohs(sack
->num_gap_ack_blocks
);
1132 * SFR-CACC algorithm:
1133 * On receipt of a SACK the sender SHOULD execute the
1134 * following statements.
1136 * 1) If the cumulative ack in the SACK passes next tsn_at_change
1137 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be
1138 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for
1140 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE
1141 * is set the receiver of the SACK MUST take the following actions:
1143 * A) Initialize the cacc_saw_newack to 0 for all destination
1146 * Only bother if changeover_active is set. Otherwise, this is
1147 * totally suboptimal to do on every SACK.
1149 if (primary
->cacc
.changeover_active
) {
1150 u8 clear_cycling
= 0;
1152 if (TSN_lte(primary
->cacc
.next_tsn_at_change
, sack_ctsn
)) {
1153 primary
->cacc
.changeover_active
= 0;
1157 if (clear_cycling
|| gap_ack_blocks
) {
1158 list_for_each_entry(transport
, transport_list
,
1161 transport
->cacc
.cycling_changeover
= 0;
1163 transport
->cacc
.cacc_saw_newack
= 0;
1168 /* Get the highest TSN in the sack. */
1169 highest_tsn
= sack_ctsn
;
1171 highest_tsn
+= ntohs(frags
[gap_ack_blocks
- 1].gab
.end
);
1173 if (TSN_lt(asoc
->highest_sacked
, highest_tsn
)) {
1174 highest_new_tsn
= highest_tsn
;
1175 asoc
->highest_sacked
= highest_tsn
;
1177 highest_new_tsn
= sctp_highest_new_tsn(sack
, asoc
);
1181 /* Run through the retransmit queue. Credit bytes received
1182 * and free those chunks that we can.
1184 sctp_check_transmitted(q
, &q
->retransmit
, NULL
, sack
, highest_new_tsn
);
1186 /* Run through the transmitted queue.
1187 * Credit bytes received and free those chunks which we can.
1189 * This is a MASSIVE candidate for optimization.
1191 list_for_each_entry(transport
, transport_list
, transports
) {
1192 sctp_check_transmitted(q
, &transport
->transmitted
,
1193 transport
, sack
, highest_new_tsn
);
1195 * SFR-CACC algorithm:
1196 * C) Let count_of_newacks be the number of
1197 * destinations for which cacc_saw_newack is set.
1199 if (transport
->cacc
.cacc_saw_newack
)
1200 count_of_newacks
++;
1203 if (gap_ack_blocks
) {
1204 list_for_each_entry(transport
, transport_list
, transports
)
1205 sctp_mark_missing(q
, &transport
->transmitted
, transport
,
1206 highest_new_tsn
, count_of_newacks
);
1209 /* Move the Cumulative TSN Ack Point if appropriate. */
1210 if (TSN_lt(asoc
->ctsn_ack_point
, sack_ctsn
))
1211 asoc
->ctsn_ack_point
= sack_ctsn
;
1213 /* Update unack_data field in the assoc. */
1214 sctp_sack_update_unack_data(asoc
, sack
);
1216 ctsn
= asoc
->ctsn_ack_point
;
1218 /* Throw away stuff rotting on the sack queue. */
1219 list_for_each_safe(lchunk
, temp
, &q
->sacked
) {
1220 tchunk
= list_entry(lchunk
, struct sctp_chunk
,
1222 tsn
= ntohl(tchunk
->subh
.data_hdr
->tsn
);
1223 if (TSN_lte(tsn
, ctsn
)) {
1224 list_del_init(&tchunk
->transmitted_list
);
1225 sctp_chunk_free(tchunk
);
1229 /* ii) Set rwnd equal to the newly received a_rwnd minus the
1230 * number of bytes still outstanding after processing the
1231 * Cumulative TSN Ack and the Gap Ack Blocks.
1234 sack_a_rwnd
= ntohl(sack
->a_rwnd
);
1235 outstanding
= q
->outstanding_bytes
;
1237 if (outstanding
< sack_a_rwnd
)
1238 sack_a_rwnd
-= outstanding
;
1242 asoc
->peer
.rwnd
= sack_a_rwnd
;
1244 sctp_generate_fwdtsn(q
, sack_ctsn
);
1246 SCTP_DEBUG_PRINTK("%s: sack Cumulative TSN Ack is 0x%x.\n",
1247 __func__
, sack_ctsn
);
1248 SCTP_DEBUG_PRINTK("%s: Cumulative TSN Ack of association, "
1249 "%p is 0x%x. Adv peer ack point: 0x%x\n",
1250 __func__
, asoc
, ctsn
, asoc
->adv_peer_ack_point
);
1252 /* See if all chunks are acked.
1253 * Make sure the empty queue handler will get run later.
1255 q
->empty
= (list_empty(&q
->out_chunk_list
) &&
1256 list_empty(&q
->retransmit
));
1260 list_for_each_entry(transport
, transport_list
, transports
) {
1261 q
->empty
= q
->empty
&& list_empty(&transport
->transmitted
);
1266 SCTP_DEBUG_PRINTK("sack queue is empty.\n");
1271 /* Is the outqueue empty? */
1272 int sctp_outq_is_empty(const struct sctp_outq
*q
)
1277 /********************************************************************
1278 * 2nd Level Abstractions
1279 ********************************************************************/
1281 /* Go through a transport's transmitted list or the association's retransmit
1282 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked.
1283 * The retransmit list will not have an associated transport.
1285 * I added coherent debug information output. --xguo
1287 * Instead of printing 'sacked' or 'kept' for each TSN on the
1288 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5.
1289 * KEPT TSN6-TSN7, etc.
1291 static void sctp_check_transmitted(struct sctp_outq
*q
,
1292 struct list_head
*transmitted_queue
,
1293 struct sctp_transport
*transport
,
1294 struct sctp_sackhdr
*sack
,
1295 __u32 highest_new_tsn_in_sack
)
1297 struct list_head
*lchunk
;
1298 struct sctp_chunk
*tchunk
;
1299 struct list_head tlist
;
1303 __u8 restart_timer
= 0;
1304 int bytes_acked
= 0;
1305 int migrate_bytes
= 0;
1307 /* These state variables are for coherent debug output. --xguo */
1310 __u32 dbg_ack_tsn
= 0; /* An ACKed TSN range starts here... */
1311 __u32 dbg_last_ack_tsn
= 0; /* ...and finishes here. */
1312 __u32 dbg_kept_tsn
= 0; /* An un-ACKed range starts here... */
1313 __u32 dbg_last_kept_tsn
= 0; /* ...and finishes here. */
1315 /* 0 : The last TSN was ACKed.
1316 * 1 : The last TSN was NOT ACKed (i.e. KEPT).
1317 * -1: We need to initialize.
1319 int dbg_prt_state
= -1;
1320 #endif /* SCTP_DEBUG */
1322 sack_ctsn
= ntohl(sack
->cum_tsn_ack
);
1324 INIT_LIST_HEAD(&tlist
);
1326 /* The while loop will skip empty transmitted queues. */
1327 while (NULL
!= (lchunk
= sctp_list_dequeue(transmitted_queue
))) {
1328 tchunk
= list_entry(lchunk
, struct sctp_chunk
,
1331 if (sctp_chunk_abandoned(tchunk
)) {
1332 /* Move the chunk to abandoned list. */
1333 sctp_insert_list(&q
->abandoned
, lchunk
);
1335 /* If this chunk has not been acked, stop
1336 * considering it as 'outstanding'.
1338 if (!tchunk
->tsn_gap_acked
) {
1339 if (tchunk
->transport
)
1340 tchunk
->transport
->flight_size
-=
1341 sctp_data_size(tchunk
);
1342 q
->outstanding_bytes
-= sctp_data_size(tchunk
);
1347 tsn
= ntohl(tchunk
->subh
.data_hdr
->tsn
);
1348 if (sctp_acked(sack
, tsn
)) {
1349 /* If this queue is the retransmit queue, the
1350 * retransmit timer has already reclaimed
1351 * the outstanding bytes for this chunk, so only
1352 * count bytes associated with a transport.
1355 /* If this chunk is being used for RTT
1356 * measurement, calculate the RTT and update
1357 * the RTO using this value.
1359 * 6.3.1 C5) Karn's algorithm: RTT measurements
1360 * MUST NOT be made using packets that were
1361 * retransmitted (and thus for which it is
1362 * ambiguous whether the reply was for the
1363 * first instance of the packet or a later
1366 if (!tchunk
->tsn_gap_acked
&&
1368 tchunk
->rtt_in_progress
) {
1369 tchunk
->rtt_in_progress
= 0;
1370 rtt
= jiffies
- tchunk
->sent_at
;
1371 sctp_transport_update_rto(transport
,
1376 /* If the chunk hasn't been marked as ACKED,
1377 * mark it and account bytes_acked if the
1378 * chunk had a valid transport (it will not
1379 * have a transport if ASCONF had deleted it
1380 * while DATA was outstanding).
1382 if (!tchunk
->tsn_gap_acked
) {
1383 tchunk
->tsn_gap_acked
= 1;
1384 bytes_acked
+= sctp_data_size(tchunk
);
1385 if (!tchunk
->transport
)
1386 migrate_bytes
+= sctp_data_size(tchunk
);
1389 if (TSN_lte(tsn
, sack_ctsn
)) {
1390 /* RFC 2960 6.3.2 Retransmission Timer Rules
1392 * R3) Whenever a SACK is received
1393 * that acknowledges the DATA chunk
1394 * with the earliest outstanding TSN
1395 * for that address, restart T3-rtx
1396 * timer for that address with its
1401 if (!tchunk
->tsn_gap_acked
) {
1403 * SFR-CACC algorithm:
1404 * 2) If the SACK contains gap acks
1405 * and the flag CHANGEOVER_ACTIVE is
1406 * set the receiver of the SACK MUST
1407 * take the following action:
1409 * B) For each TSN t being acked that
1410 * has not been acked in any SACK so
1411 * far, set cacc_saw_newack to 1 for
1412 * the destination that the TSN was
1416 sack
->num_gap_ack_blocks
&&
1417 q
->asoc
->peer
.primary_path
->cacc
.
1419 transport
->cacc
.cacc_saw_newack
1423 list_add_tail(&tchunk
->transmitted_list
,
1426 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2
1427 * M2) Each time a SACK arrives reporting
1428 * 'Stray DATA chunk(s)' record the highest TSN
1429 * reported as newly acknowledged, call this
1430 * value 'HighestTSNinSack'. A newly
1431 * acknowledged DATA chunk is one not
1432 * previously acknowledged in a SACK.
1434 * When the SCTP sender of data receives a SACK
1435 * chunk that acknowledges, for the first time,
1436 * the receipt of a DATA chunk, all the still
1437 * unacknowledged DATA chunks whose TSN is
1438 * older than that newly acknowledged DATA
1439 * chunk, are qualified as 'Stray DATA chunks'.
1441 list_add_tail(lchunk
, &tlist
);
1445 switch (dbg_prt_state
) {
1446 case 0: /* last TSN was ACKed */
1447 if (dbg_last_ack_tsn
+ 1 == tsn
) {
1448 /* This TSN belongs to the
1449 * current ACK range.
1454 if (dbg_last_ack_tsn
!= dbg_ack_tsn
) {
1455 /* Display the end of the
1458 SCTP_DEBUG_PRINTK("-%08x",
1462 /* Start a new range. */
1463 SCTP_DEBUG_PRINTK(",%08x", tsn
);
1467 case 1: /* The last TSN was NOT ACKed. */
1468 if (dbg_last_kept_tsn
!= dbg_kept_tsn
) {
1469 /* Display the end of current range. */
1470 SCTP_DEBUG_PRINTK("-%08x",
1474 SCTP_DEBUG_PRINTK("\n");
1476 /* FALL THROUGH... */
1478 /* This is the first-ever TSN we examined. */
1479 /* Start a new range of ACK-ed TSNs. */
1480 SCTP_DEBUG_PRINTK("ACKed: %08x", tsn
);
1485 dbg_last_ack_tsn
= tsn
;
1486 #endif /* SCTP_DEBUG */
1489 if (tchunk
->tsn_gap_acked
) {
1490 SCTP_DEBUG_PRINTK("%s: Receiver reneged on "
1494 tchunk
->tsn_gap_acked
= 0;
1496 if (tchunk
->transport
)
1497 bytes_acked
-= sctp_data_size(tchunk
);
1499 /* RFC 2960 6.3.2 Retransmission Timer Rules
1501 * R4) Whenever a SACK is received missing a
1502 * TSN that was previously acknowledged via a
1503 * Gap Ack Block, start T3-rtx for the
1504 * destination address to which the DATA
1505 * chunk was originally
1506 * transmitted if it is not already running.
1511 list_add_tail(lchunk
, &tlist
);
1514 /* See the above comments on ACK-ed TSNs. */
1515 switch (dbg_prt_state
) {
1517 if (dbg_last_kept_tsn
+ 1 == tsn
)
1520 if (dbg_last_kept_tsn
!= dbg_kept_tsn
)
1521 SCTP_DEBUG_PRINTK("-%08x",
1524 SCTP_DEBUG_PRINTK(",%08x", tsn
);
1529 if (dbg_last_ack_tsn
!= dbg_ack_tsn
)
1530 SCTP_DEBUG_PRINTK("-%08x",
1532 SCTP_DEBUG_PRINTK("\n");
1534 /* FALL THROUGH... */
1536 SCTP_DEBUG_PRINTK("KEPT: %08x",tsn
);
1541 dbg_last_kept_tsn
= tsn
;
1542 #endif /* SCTP_DEBUG */
1547 /* Finish off the last range, displaying its ending TSN. */
1548 switch (dbg_prt_state
) {
1550 if (dbg_last_ack_tsn
!= dbg_ack_tsn
) {
1551 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_ack_tsn
);
1553 SCTP_DEBUG_PRINTK("\n");
1558 if (dbg_last_kept_tsn
!= dbg_kept_tsn
) {
1559 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_kept_tsn
);
1561 SCTP_DEBUG_PRINTK("\n");
1564 #endif /* SCTP_DEBUG */
1567 /* We may have counted DATA that was migrated
1568 * to this transport due to DEL-IP operation.
1569 * Subtract those bytes, since the were never
1570 * send on this transport and shouldn't be
1571 * credited to this transport.
1573 bytes_acked
-= migrate_bytes
;
1575 /* 8.2. When an outstanding TSN is acknowledged,
1576 * the endpoint shall clear the error counter of
1577 * the destination transport address to which the
1578 * DATA chunk was last sent.
1579 * The association's overall error counter is
1582 transport
->error_count
= 0;
1583 transport
->asoc
->overall_error_count
= 0;
1585 /* Mark the destination transport address as
1586 * active if it is not so marked.
1588 if ((transport
->state
== SCTP_INACTIVE
) ||
1589 (transport
->state
== SCTP_UNCONFIRMED
)) {
1590 sctp_assoc_control_transport(
1594 SCTP_RECEIVED_SACK
);
1597 sctp_transport_raise_cwnd(transport
, sack_ctsn
,
1600 transport
->flight_size
-= bytes_acked
;
1601 if (transport
->flight_size
== 0)
1602 transport
->partial_bytes_acked
= 0;
1603 q
->outstanding_bytes
-= bytes_acked
+ migrate_bytes
;
1605 /* RFC 2960 6.1, sctpimpguide-06 2.15.2
1606 * When a sender is doing zero window probing, it
1607 * should not timeout the association if it continues
1608 * to receive new packets from the receiver. The
1609 * reason is that the receiver MAY keep its window
1610 * closed for an indefinite time.
1611 * A sender is doing zero window probing when the
1612 * receiver's advertised window is zero, and there is
1613 * only one data chunk in flight to the receiver.
1615 if (!q
->asoc
->peer
.rwnd
&&
1616 !list_empty(&tlist
) &&
1617 (sack_ctsn
+2 == q
->asoc
->next_tsn
)) {
1618 SCTP_DEBUG_PRINTK("%s: SACK received for zero "
1619 "window probe: %u\n",
1620 __func__
, sack_ctsn
);
1621 q
->asoc
->overall_error_count
= 0;
1622 transport
->error_count
= 0;
1626 /* RFC 2960 6.3.2 Retransmission Timer Rules
1628 * R2) Whenever all outstanding data sent to an address have
1629 * been acknowledged, turn off the T3-rtx timer of that
1632 if (!transport
->flight_size
) {
1633 if (timer_pending(&transport
->T3_rtx_timer
) &&
1634 del_timer(&transport
->T3_rtx_timer
)) {
1635 sctp_transport_put(transport
);
1637 } else if (restart_timer
) {
1638 if (!mod_timer(&transport
->T3_rtx_timer
,
1639 jiffies
+ transport
->rto
))
1640 sctp_transport_hold(transport
);
1644 list_splice(&tlist
, transmitted_queue
);
1647 /* Mark chunks as missing and consequently may get retransmitted. */
1648 static void sctp_mark_missing(struct sctp_outq
*q
,
1649 struct list_head
*transmitted_queue
,
1650 struct sctp_transport
*transport
,
1651 __u32 highest_new_tsn_in_sack
,
1652 int count_of_newacks
)
1654 struct sctp_chunk
*chunk
;
1656 char do_fast_retransmit
= 0;
1657 struct sctp_transport
*primary
= q
->asoc
->peer
.primary_path
;
1659 list_for_each_entry(chunk
, transmitted_queue
, transmitted_list
) {
1661 tsn
= ntohl(chunk
->subh
.data_hdr
->tsn
);
1663 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all
1664 * 'Unacknowledged TSN's', if the TSN number of an
1665 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack'
1666 * value, increment the 'TSN.Missing.Report' count on that
1667 * chunk if it has NOT been fast retransmitted or marked for
1668 * fast retransmit already.
1670 if (chunk
->fast_retransmit
== SCTP_CAN_FRTX
&&
1671 !chunk
->tsn_gap_acked
&&
1672 TSN_lt(tsn
, highest_new_tsn_in_sack
)) {
1674 /* SFR-CACC may require us to skip marking
1675 * this chunk as missing.
1677 if (!transport
|| !sctp_cacc_skip(primary
, transport
,
1678 count_of_newacks
, tsn
)) {
1679 chunk
->tsn_missing_report
++;
1682 "%s: TSN 0x%x missing counter: %d\n",
1684 chunk
->tsn_missing_report
);
1688 * M4) If any DATA chunk is found to have a
1689 * 'TSN.Missing.Report'
1690 * value larger than or equal to 3, mark that chunk for
1691 * retransmission and start the fast retransmit procedure.
1694 if (chunk
->tsn_missing_report
>= 3) {
1695 chunk
->fast_retransmit
= SCTP_NEED_FRTX
;
1696 do_fast_retransmit
= 1;
1701 if (do_fast_retransmit
)
1702 sctp_retransmit(q
, transport
, SCTP_RTXR_FAST_RTX
);
1704 SCTP_DEBUG_PRINTK("%s: transport: %p, cwnd: %d, "
1705 "ssthresh: %d, flight_size: %d, pba: %d\n",
1706 __func__
, transport
, transport
->cwnd
,
1707 transport
->ssthresh
, transport
->flight_size
,
1708 transport
->partial_bytes_acked
);
1712 /* Is the given TSN acked by this packet? */
1713 static int sctp_acked(struct sctp_sackhdr
*sack
, __u32 tsn
)
1716 sctp_sack_variable_t
*frags
;
1718 __u32 ctsn
= ntohl(sack
->cum_tsn_ack
);
1720 if (TSN_lte(tsn
, ctsn
))
1723 /* 3.3.4 Selective Acknowledgement (SACK) (3):
1726 * These fields contain the Gap Ack Blocks. They are repeated
1727 * for each Gap Ack Block up to the number of Gap Ack Blocks
1728 * defined in the Number of Gap Ack Blocks field. All DATA
1729 * chunks with TSNs greater than or equal to (Cumulative TSN
1730 * Ack + Gap Ack Block Start) and less than or equal to
1731 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack
1732 * Block are assumed to have been received correctly.
1735 frags
= sack
->variable
;
1737 for (i
= 0; i
< ntohs(sack
->num_gap_ack_blocks
); ++i
) {
1738 if (TSN_lte(ntohs(frags
[i
].gab
.start
), gap
) &&
1739 TSN_lte(gap
, ntohs(frags
[i
].gab
.end
)))
1748 static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip
*skiplist
,
1749 int nskips
, __be16 stream
)
1753 for (i
= 0; i
< nskips
; i
++) {
1754 if (skiplist
[i
].stream
== stream
)
1760 /* Create and add a fwdtsn chunk to the outq's control queue if needed. */
1761 static void sctp_generate_fwdtsn(struct sctp_outq
*q
, __u32 ctsn
)
1763 struct sctp_association
*asoc
= q
->asoc
;
1764 struct sctp_chunk
*ftsn_chunk
= NULL
;
1765 struct sctp_fwdtsn_skip ftsn_skip_arr
[10];
1769 struct sctp_chunk
*chunk
;
1770 struct list_head
*lchunk
, *temp
;
1772 if (!asoc
->peer
.prsctp_capable
)
1775 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the
1778 * If (Advanced.Peer.Ack.Point < SackCumAck), then update
1779 * Advanced.Peer.Ack.Point to be equal to SackCumAck.
1781 if (TSN_lt(asoc
->adv_peer_ack_point
, ctsn
))
1782 asoc
->adv_peer_ack_point
= ctsn
;
1784 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point"
1785 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as
1786 * the chunk next in the out-queue space is marked as "abandoned" as
1787 * shown in the following example:
1789 * Assuming that a SACK arrived with the Cumulative TSN ACK 102
1790 * and the Advanced.Peer.Ack.Point is updated to this value:
1792 * out-queue at the end of ==> out-queue after Adv.Ack.Point
1793 * normal SACK processing local advancement
1795 * Adv.Ack.Pt-> 102 acked 102 acked
1796 * 103 abandoned 103 abandoned
1797 * 104 abandoned Adv.Ack.P-> 104 abandoned
1799 * 106 acked 106 acked
1802 * In this example, the data sender successfully advanced the
1803 * "Advanced.Peer.Ack.Point" from 102 to 104 locally.
1805 list_for_each_safe(lchunk
, temp
, &q
->abandoned
) {
1806 chunk
= list_entry(lchunk
, struct sctp_chunk
,
1808 tsn
= ntohl(chunk
->subh
.data_hdr
->tsn
);
1810 /* Remove any chunks in the abandoned queue that are acked by
1813 if (TSN_lte(tsn
, ctsn
)) {
1814 list_del_init(lchunk
);
1815 sctp_chunk_free(chunk
);
1817 if (TSN_lte(tsn
, asoc
->adv_peer_ack_point
+1)) {
1818 asoc
->adv_peer_ack_point
= tsn
;
1819 if (chunk
->chunk_hdr
->flags
&
1820 SCTP_DATA_UNORDERED
)
1822 skip_pos
= sctp_get_skip_pos(&ftsn_skip_arr
[0],
1824 chunk
->subh
.data_hdr
->stream
);
1825 ftsn_skip_arr
[skip_pos
].stream
=
1826 chunk
->subh
.data_hdr
->stream
;
1827 ftsn_skip_arr
[skip_pos
].ssn
=
1828 chunk
->subh
.data_hdr
->ssn
;
1829 if (skip_pos
== nskips
)
1838 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point"
1839 * is greater than the Cumulative TSN ACK carried in the received
1840 * SACK, the data sender MUST send the data receiver a FORWARD TSN
1841 * chunk containing the latest value of the
1842 * "Advanced.Peer.Ack.Point".
1844 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD
1845 * list each stream and sequence number in the forwarded TSN. This
1846 * information will enable the receiver to easily find any
1847 * stranded TSN's waiting on stream reorder queues. Each stream
1848 * SHOULD only be reported once; this means that if multiple
1849 * abandoned messages occur in the same stream then only the
1850 * highest abandoned stream sequence number is reported. If the
1851 * total size of the FORWARD TSN does NOT fit in a single MTU then
1852 * the sender of the FORWARD TSN SHOULD lower the
1853 * Advanced.Peer.Ack.Point to the last TSN that will fit in a
1856 if (asoc
->adv_peer_ack_point
> ctsn
)
1857 ftsn_chunk
= sctp_make_fwdtsn(asoc
, asoc
->adv_peer_ack_point
,
1858 nskips
, &ftsn_skip_arr
[0]);
1861 list_add_tail(&ftsn_chunk
->list
, &q
->control_chunk_list
);
1862 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS
);