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, see
26 * <http://www.gnu.org/licenses/>.
28 * Please send any bug reports or fixes you make to the
30 * lksctp developers <linux-sctp@vger.kernel.org>
32 * Written or modified by:
33 * La Monte H.P. Yarroll <piggy@acm.org>
34 * Karl Knutson <karl@athena.chicago.il.us>
35 * Perry Melange <pmelange@null.cc.uic.edu>
36 * Xingang Guo <xingang.guo@intel.com>
37 * Hui Huang <hui.huang@nokia.com>
38 * Sridhar Samudrala <sri@us.ibm.com>
39 * Jon Grimm <jgrimm@us.ibm.com>
42 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
44 #include <linux/types.h>
45 #include <linux/list.h> /* For struct list_head */
46 #include <linux/socket.h>
48 #include <linux/slab.h>
49 #include <net/sock.h> /* For skb_set_owner_w */
51 #include <net/sctp/sctp.h>
52 #include <net/sctp/sm.h>
54 /* Declare internal functions here. */
55 static int sctp_acked(struct sctp_sackhdr
*sack
, __u32 tsn
);
56 static void sctp_check_transmitted(struct sctp_outq
*q
,
57 struct list_head
*transmitted_queue
,
58 struct sctp_transport
*transport
,
59 union sctp_addr
*saddr
,
60 struct sctp_sackhdr
*sack
,
61 __u32
*highest_new_tsn
);
63 static void sctp_mark_missing(struct sctp_outq
*q
,
64 struct list_head
*transmitted_queue
,
65 struct sctp_transport
*transport
,
66 __u32 highest_new_tsn
,
67 int count_of_newacks
);
69 static void sctp_generate_fwdtsn(struct sctp_outq
*q
, __u32 sack_ctsn
);
71 static void sctp_outq_flush(struct sctp_outq
*q
, int rtx_timeout
, gfp_t gfp
);
73 /* Add data to the front of the queue. */
74 static inline void sctp_outq_head_data(struct sctp_outq
*q
,
75 struct sctp_chunk
*ch
)
77 list_add(&ch
->list
, &q
->out_chunk_list
);
78 q
->out_qlen
+= ch
->skb
->len
;
81 /* Take data from the front of the queue. */
82 static inline struct sctp_chunk
*sctp_outq_dequeue_data(struct sctp_outq
*q
)
84 struct sctp_chunk
*ch
= NULL
;
86 if (!list_empty(&q
->out_chunk_list
)) {
87 struct list_head
*entry
= q
->out_chunk_list
.next
;
89 ch
= list_entry(entry
, struct sctp_chunk
, list
);
91 q
->out_qlen
-= ch
->skb
->len
;
95 /* Add data chunk to the end of the queue. */
96 static inline void sctp_outq_tail_data(struct sctp_outq
*q
,
97 struct sctp_chunk
*ch
)
99 list_add_tail(&ch
->list
, &q
->out_chunk_list
);
100 q
->out_qlen
+= ch
->skb
->len
;
104 * SFR-CACC algorithm:
105 * D) If count_of_newacks is greater than or equal to 2
106 * and t was not sent to the current primary then the
107 * sender MUST NOT increment missing report count for t.
109 static inline int sctp_cacc_skip_3_1_d(struct sctp_transport
*primary
,
110 struct sctp_transport
*transport
,
111 int count_of_newacks
)
113 if (count_of_newacks
>= 2 && transport
!= primary
)
119 * SFR-CACC algorithm:
120 * F) If count_of_newacks is less than 2, let d be the
121 * destination to which t was sent. If cacc_saw_newack
122 * is 0 for destination d, then the sender MUST NOT
123 * increment missing report count for t.
125 static inline int sctp_cacc_skip_3_1_f(struct sctp_transport
*transport
,
126 int count_of_newacks
)
128 if (count_of_newacks
< 2 &&
129 (transport
&& !transport
->cacc
.cacc_saw_newack
))
135 * SFR-CACC algorithm:
136 * 3.1) If CYCLING_CHANGEOVER is 0, the sender SHOULD
137 * execute steps C, D, F.
139 * C has been implemented in sctp_outq_sack
141 static inline int sctp_cacc_skip_3_1(struct sctp_transport
*primary
,
142 struct sctp_transport
*transport
,
143 int count_of_newacks
)
145 if (!primary
->cacc
.cycling_changeover
) {
146 if (sctp_cacc_skip_3_1_d(primary
, transport
, count_of_newacks
))
148 if (sctp_cacc_skip_3_1_f(transport
, count_of_newacks
))
156 * SFR-CACC algorithm:
157 * 3.2) Else if CYCLING_CHANGEOVER is 1, and t is less
158 * than next_tsn_at_change of the current primary, then
159 * the sender MUST NOT increment missing report count
162 static inline int sctp_cacc_skip_3_2(struct sctp_transport
*primary
, __u32 tsn
)
164 if (primary
->cacc
.cycling_changeover
&&
165 TSN_lt(tsn
, primary
->cacc
.next_tsn_at_change
))
171 * SFR-CACC algorithm:
172 * 3) If the missing report count for TSN t is to be
173 * incremented according to [RFC2960] and
174 * [SCTP_STEWART-2002], and CHANGEOVER_ACTIVE is set,
175 * then the sender MUST further execute steps 3.1 and
176 * 3.2 to determine if the missing report count for
177 * TSN t SHOULD NOT be incremented.
179 * 3.3) If 3.1 and 3.2 do not dictate that the missing
180 * report count for t should not be incremented, then
181 * the sender SHOULD increment missing report count for
182 * t (according to [RFC2960] and [SCTP_STEWART_2002]).
184 static inline int sctp_cacc_skip(struct sctp_transport
*primary
,
185 struct sctp_transport
*transport
,
186 int count_of_newacks
,
189 if (primary
->cacc
.changeover_active
&&
190 (sctp_cacc_skip_3_1(primary
, transport
, count_of_newacks
) ||
191 sctp_cacc_skip_3_2(primary
, tsn
)))
196 /* Initialize an existing sctp_outq. This does the boring stuff.
197 * You still need to define handlers if you really want to DO
198 * something with this structure...
200 void sctp_outq_init(struct sctp_association
*asoc
, struct sctp_outq
*q
)
202 memset(q
, 0, sizeof(struct sctp_outq
));
205 INIT_LIST_HEAD(&q
->out_chunk_list
);
206 INIT_LIST_HEAD(&q
->control_chunk_list
);
207 INIT_LIST_HEAD(&q
->retransmit
);
208 INIT_LIST_HEAD(&q
->sacked
);
209 INIT_LIST_HEAD(&q
->abandoned
);
212 /* Free the outqueue structure and any related pending chunks.
214 static void __sctp_outq_teardown(struct sctp_outq
*q
)
216 struct sctp_transport
*transport
;
217 struct list_head
*lchunk
, *temp
;
218 struct sctp_chunk
*chunk
, *tmp
;
220 /* Throw away unacknowledged chunks. */
221 list_for_each_entry(transport
, &q
->asoc
->peer
.transport_addr_list
,
223 while ((lchunk
= sctp_list_dequeue(&transport
->transmitted
)) != NULL
) {
224 chunk
= list_entry(lchunk
, struct sctp_chunk
,
226 /* Mark as part of a failed message. */
227 sctp_chunk_fail(chunk
, q
->error
);
228 sctp_chunk_free(chunk
);
232 /* Throw away chunks that have been gap ACKed. */
233 list_for_each_safe(lchunk
, temp
, &q
->sacked
) {
234 list_del_init(lchunk
);
235 chunk
= list_entry(lchunk
, struct sctp_chunk
,
237 sctp_chunk_fail(chunk
, q
->error
);
238 sctp_chunk_free(chunk
);
241 /* Throw away any chunks in the retransmit queue. */
242 list_for_each_safe(lchunk
, temp
, &q
->retransmit
) {
243 list_del_init(lchunk
);
244 chunk
= list_entry(lchunk
, struct sctp_chunk
,
246 sctp_chunk_fail(chunk
, q
->error
);
247 sctp_chunk_free(chunk
);
250 /* Throw away any chunks that are in the abandoned queue. */
251 list_for_each_safe(lchunk
, temp
, &q
->abandoned
) {
252 list_del_init(lchunk
);
253 chunk
= list_entry(lchunk
, struct sctp_chunk
,
255 sctp_chunk_fail(chunk
, q
->error
);
256 sctp_chunk_free(chunk
);
259 /* Throw away any leftover data chunks. */
260 while ((chunk
= sctp_outq_dequeue_data(q
)) != NULL
) {
262 /* Mark as send failure. */
263 sctp_chunk_fail(chunk
, q
->error
);
264 sctp_chunk_free(chunk
);
267 /* Throw away any leftover control chunks. */
268 list_for_each_entry_safe(chunk
, tmp
, &q
->control_chunk_list
, list
) {
269 list_del_init(&chunk
->list
);
270 sctp_chunk_free(chunk
);
274 void sctp_outq_teardown(struct sctp_outq
*q
)
276 __sctp_outq_teardown(q
);
277 sctp_outq_init(q
->asoc
, q
);
280 /* Free the outqueue structure and any related pending chunks. */
281 void sctp_outq_free(struct sctp_outq
*q
)
283 /* Throw away leftover chunks. */
284 __sctp_outq_teardown(q
);
287 /* Put a new chunk in an sctp_outq. */
288 void sctp_outq_tail(struct sctp_outq
*q
, struct sctp_chunk
*chunk
, gfp_t gfp
)
290 struct net
*net
= sock_net(q
->asoc
->base
.sk
);
292 pr_debug("%s: outq:%p, chunk:%p[%s]\n", __func__
, q
, chunk
,
293 chunk
&& chunk
->chunk_hdr
?
294 sctp_cname(SCTP_ST_CHUNK(chunk
->chunk_hdr
->type
)) :
297 /* If it is data, queue it up, otherwise, send it
300 if (sctp_chunk_is_data(chunk
)) {
301 pr_debug("%s: outqueueing: outq:%p, chunk:%p[%s])\n",
302 __func__
, q
, chunk
, chunk
&& chunk
->chunk_hdr
?
303 sctp_cname(SCTP_ST_CHUNK(chunk
->chunk_hdr
->type
)) :
306 sctp_outq_tail_data(q
, chunk
);
307 if (chunk
->asoc
->peer
.prsctp_capable
&&
308 SCTP_PR_PRIO_ENABLED(chunk
->sinfo
.sinfo_flags
))
309 chunk
->asoc
->sent_cnt_removable
++;
310 if (chunk
->chunk_hdr
->flags
& SCTP_DATA_UNORDERED
)
311 SCTP_INC_STATS(net
, SCTP_MIB_OUTUNORDERCHUNKS
);
313 SCTP_INC_STATS(net
, SCTP_MIB_OUTORDERCHUNKS
);
315 list_add_tail(&chunk
->list
, &q
->control_chunk_list
);
316 SCTP_INC_STATS(net
, SCTP_MIB_OUTCTRLCHUNKS
);
320 sctp_outq_flush(q
, 0, gfp
);
323 /* Insert a chunk into the sorted list based on the TSNs. The retransmit list
324 * and the abandoned list are in ascending order.
326 static void sctp_insert_list(struct list_head
*head
, struct list_head
*new)
328 struct list_head
*pos
;
329 struct sctp_chunk
*nchunk
, *lchunk
;
333 nchunk
= list_entry(new, struct sctp_chunk
, transmitted_list
);
334 ntsn
= ntohl(nchunk
->subh
.data_hdr
->tsn
);
336 list_for_each(pos
, head
) {
337 lchunk
= list_entry(pos
, struct sctp_chunk
, transmitted_list
);
338 ltsn
= ntohl(lchunk
->subh
.data_hdr
->tsn
);
339 if (TSN_lt(ntsn
, ltsn
)) {
340 list_add(new, pos
->prev
);
346 list_add_tail(new, head
);
349 static int sctp_prsctp_prune_sent(struct sctp_association
*asoc
,
350 struct sctp_sndrcvinfo
*sinfo
,
351 struct list_head
*queue
, int msg_len
)
353 struct sctp_chunk
*chk
, *temp
;
355 list_for_each_entry_safe(chk
, temp
, queue
, transmitted_list
) {
356 if (!SCTP_PR_PRIO_ENABLED(chk
->sinfo
.sinfo_flags
) ||
357 chk
->sinfo
.sinfo_timetolive
<= sinfo
->sinfo_timetolive
)
360 list_del_init(&chk
->transmitted_list
);
361 sctp_insert_list(&asoc
->outqueue
.abandoned
,
362 &chk
->transmitted_list
);
364 asoc
->sent_cnt_removable
--;
365 asoc
->abandoned_sent
[SCTP_PR_INDEX(PRIO
)]++;
367 if (!chk
->tsn_gap_acked
) {
369 chk
->transport
->flight_size
-=
371 asoc
->outqueue
.outstanding_bytes
-= sctp_data_size(chk
);
374 msg_len
-= SCTP_DATA_SNDSIZE(chk
) +
375 sizeof(struct sk_buff
) +
376 sizeof(struct sctp_chunk
);
384 static int sctp_prsctp_prune_unsent(struct sctp_association
*asoc
,
385 struct sctp_sndrcvinfo
*sinfo
,
386 struct list_head
*queue
, int msg_len
)
388 struct sctp_chunk
*chk
, *temp
;
390 list_for_each_entry_safe(chk
, temp
, queue
, list
) {
391 if (!SCTP_PR_PRIO_ENABLED(chk
->sinfo
.sinfo_flags
) ||
392 chk
->sinfo
.sinfo_timetolive
<= sinfo
->sinfo_timetolive
)
395 list_del_init(&chk
->list
);
396 asoc
->sent_cnt_removable
--;
397 asoc
->abandoned_unsent
[SCTP_PR_INDEX(PRIO
)]++;
399 msg_len
-= SCTP_DATA_SNDSIZE(chk
) +
400 sizeof(struct sk_buff
) +
401 sizeof(struct sctp_chunk
);
402 sctp_chunk_free(chk
);
410 /* Abandon the chunks according their priorities */
411 void sctp_prsctp_prune(struct sctp_association
*asoc
,
412 struct sctp_sndrcvinfo
*sinfo
, int msg_len
)
414 struct sctp_transport
*transport
;
416 if (!asoc
->peer
.prsctp_capable
|| !asoc
->sent_cnt_removable
)
419 msg_len
= sctp_prsctp_prune_sent(asoc
, sinfo
,
420 &asoc
->outqueue
.retransmit
,
425 list_for_each_entry(transport
, &asoc
->peer
.transport_addr_list
,
427 msg_len
= sctp_prsctp_prune_sent(asoc
, sinfo
,
428 &transport
->transmitted
,
434 sctp_prsctp_prune_unsent(asoc
, sinfo
,
435 &asoc
->outqueue
.out_chunk_list
,
439 /* Mark all the eligible packets on a transport for retransmission. */
440 void sctp_retransmit_mark(struct sctp_outq
*q
,
441 struct sctp_transport
*transport
,
444 struct list_head
*lchunk
, *ltemp
;
445 struct sctp_chunk
*chunk
;
447 /* Walk through the specified transmitted queue. */
448 list_for_each_safe(lchunk
, ltemp
, &transport
->transmitted
) {
449 chunk
= list_entry(lchunk
, struct sctp_chunk
,
452 /* If the chunk is abandoned, move it to abandoned list. */
453 if (sctp_chunk_abandoned(chunk
)) {
454 list_del_init(lchunk
);
455 sctp_insert_list(&q
->abandoned
, lchunk
);
457 /* If this chunk has not been previousely acked,
458 * stop considering it 'outstanding'. Our peer
459 * will most likely never see it since it will
460 * not be retransmitted
462 if (!chunk
->tsn_gap_acked
) {
463 if (chunk
->transport
)
464 chunk
->transport
->flight_size
-=
465 sctp_data_size(chunk
);
466 q
->outstanding_bytes
-= sctp_data_size(chunk
);
467 q
->asoc
->peer
.rwnd
+= sctp_data_size(chunk
);
472 /* If we are doing retransmission due to a timeout or pmtu
473 * discovery, only the chunks that are not yet acked should
474 * be added to the retransmit queue.
476 if ((reason
== SCTP_RTXR_FAST_RTX
&&
477 (chunk
->fast_retransmit
== SCTP_NEED_FRTX
)) ||
478 (reason
!= SCTP_RTXR_FAST_RTX
&& !chunk
->tsn_gap_acked
)) {
479 /* RFC 2960 6.2.1 Processing a Received SACK
481 * C) Any time a DATA chunk is marked for
482 * retransmission (via either T3-rtx timer expiration
483 * (Section 6.3.3) or via fast retransmit
484 * (Section 7.2.4)), add the data size of those
485 * chunks to the rwnd.
487 q
->asoc
->peer
.rwnd
+= sctp_data_size(chunk
);
488 q
->outstanding_bytes
-= sctp_data_size(chunk
);
489 if (chunk
->transport
)
490 transport
->flight_size
-= sctp_data_size(chunk
);
492 /* sctpimpguide-05 Section 2.8.2
493 * M5) If a T3-rtx timer expires, the
494 * 'TSN.Missing.Report' of all affected TSNs is set
497 chunk
->tsn_missing_report
= 0;
499 /* If a chunk that is being used for RTT measurement
500 * has to be retransmitted, we cannot use this chunk
501 * anymore for RTT measurements. Reset rto_pending so
502 * that a new RTT measurement is started when a new
503 * data chunk is sent.
505 if (chunk
->rtt_in_progress
) {
506 chunk
->rtt_in_progress
= 0;
507 transport
->rto_pending
= 0;
510 /* Move the chunk to the retransmit queue. The chunks
511 * on the retransmit queue are always kept in order.
513 list_del_init(lchunk
);
514 sctp_insert_list(&q
->retransmit
, lchunk
);
518 pr_debug("%s: transport:%p, reason:%d, cwnd:%d, ssthresh:%d, "
519 "flight_size:%d, pba:%d\n", __func__
, transport
, reason
,
520 transport
->cwnd
, transport
->ssthresh
, transport
->flight_size
,
521 transport
->partial_bytes_acked
);
524 /* Mark all the eligible packets on a transport for retransmission and force
527 void sctp_retransmit(struct sctp_outq
*q
, struct sctp_transport
*transport
,
528 sctp_retransmit_reason_t reason
)
530 struct net
*net
= sock_net(q
->asoc
->base
.sk
);
533 case SCTP_RTXR_T3_RTX
:
534 SCTP_INC_STATS(net
, SCTP_MIB_T3_RETRANSMITS
);
535 sctp_transport_lower_cwnd(transport
, SCTP_LOWER_CWND_T3_RTX
);
536 /* Update the retran path if the T3-rtx timer has expired for
537 * the current retran path.
539 if (transport
== transport
->asoc
->peer
.retran_path
)
540 sctp_assoc_update_retran_path(transport
->asoc
);
541 transport
->asoc
->rtx_data_chunks
+=
542 transport
->asoc
->unack_data
;
544 case SCTP_RTXR_FAST_RTX
:
545 SCTP_INC_STATS(net
, SCTP_MIB_FAST_RETRANSMITS
);
546 sctp_transport_lower_cwnd(transport
, SCTP_LOWER_CWND_FAST_RTX
);
549 case SCTP_RTXR_PMTUD
:
550 SCTP_INC_STATS(net
, SCTP_MIB_PMTUD_RETRANSMITS
);
552 case SCTP_RTXR_T1_RTX
:
553 SCTP_INC_STATS(net
, SCTP_MIB_T1_RETRANSMITS
);
554 transport
->asoc
->init_retries
++;
560 sctp_retransmit_mark(q
, transport
, reason
);
562 /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination,
563 * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by
564 * following the procedures outlined in C1 - C5.
566 if (reason
== SCTP_RTXR_T3_RTX
)
567 sctp_generate_fwdtsn(q
, q
->asoc
->ctsn_ack_point
);
569 /* Flush the queues only on timeout, since fast_rtx is only
570 * triggered during sack processing and the queue
571 * will be flushed at the end.
573 if (reason
!= SCTP_RTXR_FAST_RTX
)
574 sctp_outq_flush(q
, /* rtx_timeout */ 1, GFP_ATOMIC
);
578 * Transmit DATA chunks on the retransmit queue. Upon return from
579 * sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which
580 * need to be transmitted by the caller.
581 * We assume that pkt->transport has already been set.
583 * The return value is a normal kernel error return value.
585 static int sctp_outq_flush_rtx(struct sctp_outq
*q
, struct sctp_packet
*pkt
,
586 int rtx_timeout
, int *start_timer
)
588 struct list_head
*lqueue
;
589 struct sctp_transport
*transport
= pkt
->transport
;
591 struct sctp_chunk
*chunk
, *chunk1
;
597 lqueue
= &q
->retransmit
;
598 fast_rtx
= q
->fast_rtx
;
600 /* This loop handles time-out retransmissions, fast retransmissions,
601 * and retransmissions due to opening of whindow.
603 * RFC 2960 6.3.3 Handle T3-rtx Expiration
605 * E3) Determine how many of the earliest (i.e., lowest TSN)
606 * outstanding DATA chunks for the address for which the
607 * T3-rtx has expired will fit into a single packet, subject
608 * to the MTU constraint for the path corresponding to the
609 * destination transport address to which the retransmission
610 * is being sent (this may be different from the address for
611 * which the timer expires [see Section 6.4]). Call this value
612 * K. Bundle and retransmit those K DATA chunks in a single
613 * packet to the destination endpoint.
615 * [Just to be painfully clear, if we are retransmitting
616 * because a timeout just happened, we should send only ONE
617 * packet of retransmitted data.]
619 * For fast retransmissions we also send only ONE packet. However,
620 * if we are just flushing the queue due to open window, we'll
621 * try to send as much as possible.
623 list_for_each_entry_safe(chunk
, chunk1
, lqueue
, transmitted_list
) {
624 /* If the chunk is abandoned, move it to abandoned list. */
625 if (sctp_chunk_abandoned(chunk
)) {
626 list_del_init(&chunk
->transmitted_list
);
627 sctp_insert_list(&q
->abandoned
,
628 &chunk
->transmitted_list
);
632 /* Make sure that Gap Acked TSNs are not retransmitted. A
633 * simple approach is just to move such TSNs out of the
634 * way and into a 'transmitted' queue and skip to the
637 if (chunk
->tsn_gap_acked
) {
638 list_move_tail(&chunk
->transmitted_list
,
639 &transport
->transmitted
);
643 /* If we are doing fast retransmit, ignore non-fast_rtransmit
646 if (fast_rtx
&& !chunk
->fast_retransmit
)
650 /* Attempt to append this chunk to the packet. */
651 status
= sctp_packet_append_chunk(pkt
, chunk
);
654 case SCTP_XMIT_PMTU_FULL
:
655 if (!pkt
->has_data
&& !pkt
->has_cookie_echo
) {
656 /* If this packet did not contain DATA then
657 * retransmission did not happen, so do it
658 * again. We'll ignore the error here since
659 * control chunks are already freed so there
660 * is nothing we can do.
662 sctp_packet_transmit(pkt
, GFP_ATOMIC
);
666 /* Send this packet. */
667 error
= sctp_packet_transmit(pkt
, GFP_ATOMIC
);
669 /* If we are retransmitting, we should only
670 * send a single packet.
671 * Otherwise, try appending this chunk again.
673 if (rtx_timeout
|| fast_rtx
)
678 /* Bundle next chunk in the next round. */
681 case SCTP_XMIT_RWND_FULL
:
682 /* Send this packet. */
683 error
= sctp_packet_transmit(pkt
, GFP_ATOMIC
);
685 /* Stop sending DATA as there is no more room
691 case SCTP_XMIT_DELAY
:
692 /* Send this packet. */
693 error
= sctp_packet_transmit(pkt
, GFP_ATOMIC
);
695 /* Stop sending DATA because of nagle delay. */
700 /* The append was successful, so add this chunk to
701 * the transmitted list.
703 list_move_tail(&chunk
->transmitted_list
,
704 &transport
->transmitted
);
706 /* Mark the chunk as ineligible for fast retransmit
707 * after it is retransmitted.
709 if (chunk
->fast_retransmit
== SCTP_NEED_FRTX
)
710 chunk
->fast_retransmit
= SCTP_DONT_FRTX
;
712 q
->asoc
->stats
.rtxchunks
++;
716 /* Set the timer if there were no errors */
717 if (!error
&& !timer
)
724 /* If we are here due to a retransmit timeout or a fast
725 * retransmit and if there are any chunks left in the retransmit
726 * queue that could not fit in the PMTU sized packet, they need
727 * to be marked as ineligible for a subsequent fast retransmit.
729 if (rtx_timeout
|| fast_rtx
) {
730 list_for_each_entry(chunk1
, lqueue
, transmitted_list
) {
731 if (chunk1
->fast_retransmit
== SCTP_NEED_FRTX
)
732 chunk1
->fast_retransmit
= SCTP_DONT_FRTX
;
736 *start_timer
= timer
;
738 /* Clear fast retransmit hint */
745 /* Cork the outqueue so queued chunks are really queued. */
746 void sctp_outq_uncork(struct sctp_outq
*q
, gfp_t gfp
)
751 sctp_outq_flush(q
, 0, gfp
);
756 * Try to flush an outqueue.
758 * Description: Send everything in q which we legally can, subject to
759 * congestion limitations.
760 * * Note: This function can be called from multiple contexts so appropriate
761 * locking concerns must be made. Today we use the sock lock to protect
764 static void sctp_outq_flush(struct sctp_outq
*q
, int rtx_timeout
, gfp_t gfp
)
766 struct sctp_packet
*packet
;
767 struct sctp_packet singleton
;
768 struct sctp_association
*asoc
= q
->asoc
;
769 __u16 sport
= asoc
->base
.bind_addr
.port
;
770 __u16 dport
= asoc
->peer
.port
;
771 __u32 vtag
= asoc
->peer
.i
.init_tag
;
772 struct sctp_transport
*transport
= NULL
;
773 struct sctp_transport
*new_transport
;
774 struct sctp_chunk
*chunk
, *tmp
;
780 /* These transports have chunks to send. */
781 struct list_head transport_list
;
782 struct list_head
*ltransport
;
784 INIT_LIST_HEAD(&transport_list
);
790 * When bundling control chunks with DATA chunks, an
791 * endpoint MUST place control chunks first in the outbound
792 * SCTP packet. The transmitter MUST transmit DATA chunks
793 * within a SCTP packet in increasing order of TSN.
797 list_for_each_entry_safe(chunk
, tmp
, &q
->control_chunk_list
, list
) {
799 * F1) This means that until such time as the ASCONF
800 * containing the add is acknowledged, the sender MUST
801 * NOT use the new IP address as a source for ANY SCTP
802 * packet except on carrying an ASCONF Chunk.
804 if (asoc
->src_out_of_asoc_ok
&&
805 chunk
->chunk_hdr
->type
!= SCTP_CID_ASCONF
)
808 list_del_init(&chunk
->list
);
810 /* Pick the right transport to use. */
811 new_transport
= chunk
->transport
;
813 if (!new_transport
) {
815 * If we have a prior transport pointer, see if
816 * the destination address of the chunk
817 * matches the destination address of the
818 * current transport. If not a match, then
819 * try to look up the transport with a given
820 * destination address. We do this because
821 * after processing ASCONFs, we may have new
822 * transports created.
825 sctp_cmp_addr_exact(&chunk
->dest
,
827 new_transport
= transport
;
829 new_transport
= sctp_assoc_lookup_paddr(asoc
,
832 /* if we still don't have a new transport, then
833 * use the current active path.
836 new_transport
= asoc
->peer
.active_path
;
837 } else if ((new_transport
->state
== SCTP_INACTIVE
) ||
838 (new_transport
->state
== SCTP_UNCONFIRMED
) ||
839 (new_transport
->state
== SCTP_PF
)) {
840 /* If the chunk is Heartbeat or Heartbeat Ack,
841 * send it to chunk->transport, even if it's
844 * 3.3.6 Heartbeat Acknowledgement:
846 * A HEARTBEAT ACK is always sent to the source IP
847 * address of the IP datagram containing the
848 * HEARTBEAT chunk to which this ack is responding.
851 * ASCONF_ACKs also must be sent to the source.
853 if (chunk
->chunk_hdr
->type
!= SCTP_CID_HEARTBEAT
&&
854 chunk
->chunk_hdr
->type
!= SCTP_CID_HEARTBEAT_ACK
&&
855 chunk
->chunk_hdr
->type
!= SCTP_CID_ASCONF_ACK
)
856 new_transport
= asoc
->peer
.active_path
;
859 /* Are we switching transports?
860 * Take care of transport locks.
862 if (new_transport
!= transport
) {
863 transport
= new_transport
;
864 if (list_empty(&transport
->send_ready
)) {
865 list_add_tail(&transport
->send_ready
,
868 packet
= &transport
->packet
;
869 sctp_packet_config(packet
, vtag
,
870 asoc
->peer
.ecn_capable
);
873 switch (chunk
->chunk_hdr
->type
) {
877 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN
878 * COMPLETE with any other chunks. [Send them immediately.]
881 case SCTP_CID_INIT_ACK
:
882 case SCTP_CID_SHUTDOWN_COMPLETE
:
883 sctp_packet_init(&singleton
, transport
, sport
, dport
);
884 sctp_packet_config(&singleton
, vtag
, 0);
885 sctp_packet_append_chunk(&singleton
, chunk
);
886 error
= sctp_packet_transmit(&singleton
, gfp
);
888 asoc
->base
.sk
->sk_err
= -error
;
894 if (sctp_test_T_bit(chunk
)) {
895 packet
->vtag
= asoc
->c
.my_vtag
;
897 /* The following chunks are "response" chunks, i.e.
898 * they are generated in response to something we
899 * received. If we are sending these, then we can
900 * send only 1 packet containing these chunks.
902 case SCTP_CID_HEARTBEAT_ACK
:
903 case SCTP_CID_SHUTDOWN_ACK
:
904 case SCTP_CID_COOKIE_ACK
:
905 case SCTP_CID_COOKIE_ECHO
:
907 case SCTP_CID_ECN_CWR
:
908 case SCTP_CID_ASCONF_ACK
:
913 case SCTP_CID_HEARTBEAT
:
914 case SCTP_CID_SHUTDOWN
:
915 case SCTP_CID_ECN_ECNE
:
916 case SCTP_CID_ASCONF
:
917 case SCTP_CID_FWD_TSN
:
918 case SCTP_CID_RECONF
:
919 status
= sctp_packet_transmit_chunk(packet
, chunk
,
921 if (status
!= SCTP_XMIT_OK
) {
922 /* put the chunk back */
923 list_add(&chunk
->list
, &q
->control_chunk_list
);
927 asoc
->stats
.octrlchunks
++;
928 /* PR-SCTP C5) If a FORWARD TSN is sent, the
929 * sender MUST assure that at least one T3-rtx
932 if (chunk
->chunk_hdr
->type
== SCTP_CID_FWD_TSN
) {
933 sctp_transport_reset_t3_rtx(transport
);
934 transport
->last_time_sent
= jiffies
;
937 if (chunk
== asoc
->strreset_chunk
)
938 sctp_transport_reset_reconf_timer(transport
);
943 /* We built a chunk with an illegal type! */
948 if (q
->asoc
->src_out_of_asoc_ok
)
951 /* Is it OK to send data chunks? */
952 switch (asoc
->state
) {
953 case SCTP_STATE_COOKIE_ECHOED
:
954 /* Only allow bundling when this packet has a COOKIE-ECHO
957 if (!packet
|| !packet
->has_cookie_echo
)
961 case SCTP_STATE_ESTABLISHED
:
962 case SCTP_STATE_SHUTDOWN_PENDING
:
963 case SCTP_STATE_SHUTDOWN_RECEIVED
:
965 * RFC 2960 6.1 Transmission of DATA Chunks
967 * C) When the time comes for the sender to transmit,
968 * before sending new DATA chunks, the sender MUST
969 * first transmit any outstanding DATA chunks which
970 * are marked for retransmission (limited by the
973 if (!list_empty(&q
->retransmit
)) {
974 if (asoc
->peer
.retran_path
->state
== SCTP_UNCONFIRMED
)
976 if (transport
== asoc
->peer
.retran_path
)
979 /* Switch transports & prepare the packet. */
981 transport
= asoc
->peer
.retran_path
;
983 if (list_empty(&transport
->send_ready
)) {
984 list_add_tail(&transport
->send_ready
,
988 packet
= &transport
->packet
;
989 sctp_packet_config(packet
, vtag
,
990 asoc
->peer
.ecn_capable
);
992 error
= sctp_outq_flush_rtx(q
, packet
,
993 rtx_timeout
, &start_timer
);
995 asoc
->base
.sk
->sk_err
= -error
;
998 sctp_transport_reset_t3_rtx(transport
);
999 transport
->last_time_sent
= jiffies
;
1002 /* This can happen on COOKIE-ECHO resend. Only
1003 * one chunk can get bundled with a COOKIE-ECHO.
1005 if (packet
->has_cookie_echo
)
1006 goto sctp_flush_out
;
1008 /* Don't send new data if there is still data
1009 * waiting to retransmit.
1011 if (!list_empty(&q
->retransmit
))
1012 goto sctp_flush_out
;
1015 /* Apply Max.Burst limitation to the current transport in
1016 * case it will be used for new data. We are going to
1017 * rest it before we return, but we want to apply the limit
1018 * to the currently queued data.
1021 sctp_transport_burst_limited(transport
);
1023 /* Finally, transmit new packets. */
1024 while ((chunk
= sctp_outq_dequeue_data(q
)) != NULL
) {
1025 __u32 sid
= ntohs(chunk
->subh
.data_hdr
->stream
);
1027 /* RFC 2960 6.5 Every DATA chunk MUST carry a valid
1028 * stream identifier.
1030 if (chunk
->sinfo
.sinfo_stream
>=
1031 asoc
->c
.sinit_num_ostreams
) {
1033 /* Mark as failed send. */
1034 sctp_chunk_fail(chunk
, SCTP_ERROR_INV_STRM
);
1035 if (asoc
->peer
.prsctp_capable
&&
1036 SCTP_PR_PRIO_ENABLED(chunk
->sinfo
.sinfo_flags
))
1037 asoc
->sent_cnt_removable
--;
1038 sctp_chunk_free(chunk
);
1042 /* Has this chunk expired? */
1043 if (sctp_chunk_abandoned(chunk
)) {
1044 sctp_chunk_fail(chunk
, 0);
1045 sctp_chunk_free(chunk
);
1049 if (asoc
->stream
->out
[sid
].state
== SCTP_STREAM_CLOSED
) {
1050 sctp_outq_head_data(q
, chunk
);
1051 goto sctp_flush_out
;
1054 /* If there is a specified transport, use it.
1055 * Otherwise, we want to use the active path.
1057 new_transport
= chunk
->transport
;
1058 if (!new_transport
||
1059 ((new_transport
->state
== SCTP_INACTIVE
) ||
1060 (new_transport
->state
== SCTP_UNCONFIRMED
) ||
1061 (new_transport
->state
== SCTP_PF
)))
1062 new_transport
= asoc
->peer
.active_path
;
1063 if (new_transport
->state
== SCTP_UNCONFIRMED
) {
1064 WARN_ONCE(1, "Attempt to send packet on unconfirmed path.");
1065 sctp_chunk_fail(chunk
, 0);
1066 sctp_chunk_free(chunk
);
1070 /* Change packets if necessary. */
1071 if (new_transport
!= transport
) {
1072 transport
= new_transport
;
1074 /* Schedule to have this transport's
1077 if (list_empty(&transport
->send_ready
)) {
1078 list_add_tail(&transport
->send_ready
,
1082 packet
= &transport
->packet
;
1083 sctp_packet_config(packet
, vtag
,
1084 asoc
->peer
.ecn_capable
);
1085 /* We've switched transports, so apply the
1086 * Burst limit to the new transport.
1088 sctp_transport_burst_limited(transport
);
1091 pr_debug("%s: outq:%p, chunk:%p[%s], tx-tsn:0x%x skb->head:%p "
1093 __func__
, q
, chunk
, chunk
&& chunk
->chunk_hdr
?
1094 sctp_cname(SCTP_ST_CHUNK(chunk
->chunk_hdr
->type
)) :
1095 "illegal chunk", ntohl(chunk
->subh
.data_hdr
->tsn
),
1096 chunk
->skb
? chunk
->skb
->head
: NULL
, chunk
->skb
?
1097 atomic_read(&chunk
->skb
->users
) : -1);
1099 /* Add the chunk to the packet. */
1100 status
= sctp_packet_transmit_chunk(packet
, chunk
, 0, gfp
);
1103 case SCTP_XMIT_PMTU_FULL
:
1104 case SCTP_XMIT_RWND_FULL
:
1105 case SCTP_XMIT_DELAY
:
1106 /* We could not append this chunk, so put
1107 * the chunk back on the output queue.
1109 pr_debug("%s: could not transmit tsn:0x%x, status:%d\n",
1110 __func__
, ntohl(chunk
->subh
.data_hdr
->tsn
),
1113 sctp_outq_head_data(q
, chunk
);
1114 goto sctp_flush_out
;
1117 /* The sender is in the SHUTDOWN-PENDING state,
1118 * The sender MAY set the I-bit in the DATA
1121 if (asoc
->state
== SCTP_STATE_SHUTDOWN_PENDING
)
1122 chunk
->chunk_hdr
->flags
|= SCTP_DATA_SACK_IMM
;
1123 if (chunk
->chunk_hdr
->flags
& SCTP_DATA_UNORDERED
)
1124 asoc
->stats
.ouodchunks
++;
1126 asoc
->stats
.oodchunks
++;
1134 /* BUG: We assume that the sctp_packet_transmit()
1135 * call below will succeed all the time and add the
1136 * chunk to the transmitted list and restart the
1138 * It is possible that the call can fail under OOM
1141 * Is this really a problem? Won't this behave
1144 list_add_tail(&chunk
->transmitted_list
,
1145 &transport
->transmitted
);
1147 sctp_transport_reset_t3_rtx(transport
);
1148 transport
->last_time_sent
= jiffies
;
1150 /* Only let one DATA chunk get bundled with a
1151 * COOKIE-ECHO chunk.
1153 if (packet
->has_cookie_echo
)
1154 goto sctp_flush_out
;
1165 /* Before returning, examine all the transports touched in
1166 * this call. Right now, we bluntly force clear all the
1167 * transports. Things might change after we implement Nagle.
1168 * But such an examination is still required.
1172 while ((ltransport
= sctp_list_dequeue(&transport_list
)) != NULL
) {
1173 struct sctp_transport
*t
= list_entry(ltransport
,
1174 struct sctp_transport
,
1176 packet
= &t
->packet
;
1177 if (!sctp_packet_empty(packet
)) {
1178 error
= sctp_packet_transmit(packet
, gfp
);
1180 asoc
->base
.sk
->sk_err
= -error
;
1183 /* Clear the burst limited state, if any */
1184 sctp_transport_burst_reset(t
);
1188 /* Update unack_data based on the incoming SACK chunk */
1189 static void sctp_sack_update_unack_data(struct sctp_association
*assoc
,
1190 struct sctp_sackhdr
*sack
)
1192 sctp_sack_variable_t
*frags
;
1196 unack_data
= assoc
->next_tsn
- assoc
->ctsn_ack_point
- 1;
1198 frags
= sack
->variable
;
1199 for (i
= 0; i
< ntohs(sack
->num_gap_ack_blocks
); i
++) {
1200 unack_data
-= ((ntohs(frags
[i
].gab
.end
) -
1201 ntohs(frags
[i
].gab
.start
) + 1));
1204 assoc
->unack_data
= unack_data
;
1207 /* This is where we REALLY process a SACK.
1209 * Process the SACK against the outqueue. Mostly, this just frees
1210 * things off the transmitted queue.
1212 int sctp_outq_sack(struct sctp_outq
*q
, struct sctp_chunk
*chunk
)
1214 struct sctp_association
*asoc
= q
->asoc
;
1215 struct sctp_sackhdr
*sack
= chunk
->subh
.sack_hdr
;
1216 struct sctp_transport
*transport
;
1217 struct sctp_chunk
*tchunk
= NULL
;
1218 struct list_head
*lchunk
, *transport_list
, *temp
;
1219 sctp_sack_variable_t
*frags
= sack
->variable
;
1220 __u32 sack_ctsn
, ctsn
, tsn
;
1221 __u32 highest_tsn
, highest_new_tsn
;
1223 unsigned int outstanding
;
1224 struct sctp_transport
*primary
= asoc
->peer
.primary_path
;
1225 int count_of_newacks
= 0;
1229 /* Grab the association's destination address list. */
1230 transport_list
= &asoc
->peer
.transport_addr_list
;
1232 sack_ctsn
= ntohl(sack
->cum_tsn_ack
);
1233 gap_ack_blocks
= ntohs(sack
->num_gap_ack_blocks
);
1234 asoc
->stats
.gapcnt
+= gap_ack_blocks
;
1236 * SFR-CACC algorithm:
1237 * On receipt of a SACK the sender SHOULD execute the
1238 * following statements.
1240 * 1) If the cumulative ack in the SACK passes next tsn_at_change
1241 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be
1242 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for
1244 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE
1245 * is set the receiver of the SACK MUST take the following actions:
1247 * A) Initialize the cacc_saw_newack to 0 for all destination
1250 * Only bother if changeover_active is set. Otherwise, this is
1251 * totally suboptimal to do on every SACK.
1253 if (primary
->cacc
.changeover_active
) {
1254 u8 clear_cycling
= 0;
1256 if (TSN_lte(primary
->cacc
.next_tsn_at_change
, sack_ctsn
)) {
1257 primary
->cacc
.changeover_active
= 0;
1261 if (clear_cycling
|| gap_ack_blocks
) {
1262 list_for_each_entry(transport
, transport_list
,
1265 transport
->cacc
.cycling_changeover
= 0;
1267 transport
->cacc
.cacc_saw_newack
= 0;
1272 /* Get the highest TSN in the sack. */
1273 highest_tsn
= sack_ctsn
;
1275 highest_tsn
+= ntohs(frags
[gap_ack_blocks
- 1].gab
.end
);
1277 if (TSN_lt(asoc
->highest_sacked
, highest_tsn
))
1278 asoc
->highest_sacked
= highest_tsn
;
1280 highest_new_tsn
= sack_ctsn
;
1282 /* Run through the retransmit queue. Credit bytes received
1283 * and free those chunks that we can.
1285 sctp_check_transmitted(q
, &q
->retransmit
, NULL
, NULL
, sack
, &highest_new_tsn
);
1287 /* Run through the transmitted queue.
1288 * Credit bytes received and free those chunks which we can.
1290 * This is a MASSIVE candidate for optimization.
1292 list_for_each_entry(transport
, transport_list
, transports
) {
1293 sctp_check_transmitted(q
, &transport
->transmitted
,
1294 transport
, &chunk
->source
, sack
,
1297 * SFR-CACC algorithm:
1298 * C) Let count_of_newacks be the number of
1299 * destinations for which cacc_saw_newack is set.
1301 if (transport
->cacc
.cacc_saw_newack
)
1305 /* Move the Cumulative TSN Ack Point if appropriate. */
1306 if (TSN_lt(asoc
->ctsn_ack_point
, sack_ctsn
)) {
1307 asoc
->ctsn_ack_point
= sack_ctsn
;
1311 if (gap_ack_blocks
) {
1313 if (asoc
->fast_recovery
&& accum_moved
)
1314 highest_new_tsn
= highest_tsn
;
1316 list_for_each_entry(transport
, transport_list
, transports
)
1317 sctp_mark_missing(q
, &transport
->transmitted
, transport
,
1318 highest_new_tsn
, count_of_newacks
);
1321 /* Update unack_data field in the assoc. */
1322 sctp_sack_update_unack_data(asoc
, sack
);
1324 ctsn
= asoc
->ctsn_ack_point
;
1326 /* Throw away stuff rotting on the sack queue. */
1327 list_for_each_safe(lchunk
, temp
, &q
->sacked
) {
1328 tchunk
= list_entry(lchunk
, struct sctp_chunk
,
1330 tsn
= ntohl(tchunk
->subh
.data_hdr
->tsn
);
1331 if (TSN_lte(tsn
, ctsn
)) {
1332 list_del_init(&tchunk
->transmitted_list
);
1333 if (asoc
->peer
.prsctp_capable
&&
1334 SCTP_PR_PRIO_ENABLED(chunk
->sinfo
.sinfo_flags
))
1335 asoc
->sent_cnt_removable
--;
1336 sctp_chunk_free(tchunk
);
1340 /* ii) Set rwnd equal to the newly received a_rwnd minus the
1341 * number of bytes still outstanding after processing the
1342 * Cumulative TSN Ack and the Gap Ack Blocks.
1345 sack_a_rwnd
= ntohl(sack
->a_rwnd
);
1346 asoc
->peer
.zero_window_announced
= !sack_a_rwnd
;
1347 outstanding
= q
->outstanding_bytes
;
1349 if (outstanding
< sack_a_rwnd
)
1350 sack_a_rwnd
-= outstanding
;
1354 asoc
->peer
.rwnd
= sack_a_rwnd
;
1356 sctp_generate_fwdtsn(q
, sack_ctsn
);
1358 pr_debug("%s: sack cumulative tsn ack:0x%x\n", __func__
, sack_ctsn
);
1359 pr_debug("%s: cumulative tsn ack of assoc:%p is 0x%x, "
1360 "advertised peer ack point:0x%x\n", __func__
, asoc
, ctsn
,
1361 asoc
->adv_peer_ack_point
);
1363 return sctp_outq_is_empty(q
);
1366 /* Is the outqueue empty?
1367 * The queue is empty when we have not pending data, no in-flight data
1368 * and nothing pending retransmissions.
1370 int sctp_outq_is_empty(const struct sctp_outq
*q
)
1372 return q
->out_qlen
== 0 && q
->outstanding_bytes
== 0 &&
1373 list_empty(&q
->retransmit
);
1376 /********************************************************************
1377 * 2nd Level Abstractions
1378 ********************************************************************/
1380 /* Go through a transport's transmitted list or the association's retransmit
1381 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked.
1382 * The retransmit list will not have an associated transport.
1384 * I added coherent debug information output. --xguo
1386 * Instead of printing 'sacked' or 'kept' for each TSN on the
1387 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5.
1388 * KEPT TSN6-TSN7, etc.
1390 static void sctp_check_transmitted(struct sctp_outq
*q
,
1391 struct list_head
*transmitted_queue
,
1392 struct sctp_transport
*transport
,
1393 union sctp_addr
*saddr
,
1394 struct sctp_sackhdr
*sack
,
1395 __u32
*highest_new_tsn_in_sack
)
1397 struct list_head
*lchunk
;
1398 struct sctp_chunk
*tchunk
;
1399 struct list_head tlist
;
1403 __u8 restart_timer
= 0;
1404 int bytes_acked
= 0;
1405 int migrate_bytes
= 0;
1406 bool forward_progress
= false;
1408 sack_ctsn
= ntohl(sack
->cum_tsn_ack
);
1410 INIT_LIST_HEAD(&tlist
);
1412 /* The while loop will skip empty transmitted queues. */
1413 while (NULL
!= (lchunk
= sctp_list_dequeue(transmitted_queue
))) {
1414 tchunk
= list_entry(lchunk
, struct sctp_chunk
,
1417 if (sctp_chunk_abandoned(tchunk
)) {
1418 /* Move the chunk to abandoned list. */
1419 sctp_insert_list(&q
->abandoned
, lchunk
);
1421 /* If this chunk has not been acked, stop
1422 * considering it as 'outstanding'.
1424 if (!tchunk
->tsn_gap_acked
) {
1425 if (tchunk
->transport
)
1426 tchunk
->transport
->flight_size
-=
1427 sctp_data_size(tchunk
);
1428 q
->outstanding_bytes
-= sctp_data_size(tchunk
);
1433 tsn
= ntohl(tchunk
->subh
.data_hdr
->tsn
);
1434 if (sctp_acked(sack
, tsn
)) {
1435 /* If this queue is the retransmit queue, the
1436 * retransmit timer has already reclaimed
1437 * the outstanding bytes for this chunk, so only
1438 * count bytes associated with a transport.
1441 /* If this chunk is being used for RTT
1442 * measurement, calculate the RTT and update
1443 * the RTO using this value.
1445 * 6.3.1 C5) Karn's algorithm: RTT measurements
1446 * MUST NOT be made using packets that were
1447 * retransmitted (and thus for which it is
1448 * ambiguous whether the reply was for the
1449 * first instance of the packet or a later
1452 if (!tchunk
->tsn_gap_acked
&&
1453 !sctp_chunk_retransmitted(tchunk
) &&
1454 tchunk
->rtt_in_progress
) {
1455 tchunk
->rtt_in_progress
= 0;
1456 rtt
= jiffies
- tchunk
->sent_at
;
1457 sctp_transport_update_rto(transport
,
1462 /* If the chunk hasn't been marked as ACKED,
1463 * mark it and account bytes_acked if the
1464 * chunk had a valid transport (it will not
1465 * have a transport if ASCONF had deleted it
1466 * while DATA was outstanding).
1468 if (!tchunk
->tsn_gap_acked
) {
1469 tchunk
->tsn_gap_acked
= 1;
1470 if (TSN_lt(*highest_new_tsn_in_sack
, tsn
))
1471 *highest_new_tsn_in_sack
= tsn
;
1472 bytes_acked
+= sctp_data_size(tchunk
);
1473 if (!tchunk
->transport
)
1474 migrate_bytes
+= sctp_data_size(tchunk
);
1475 forward_progress
= true;
1478 if (TSN_lte(tsn
, sack_ctsn
)) {
1479 /* RFC 2960 6.3.2 Retransmission Timer Rules
1481 * R3) Whenever a SACK is received
1482 * that acknowledges the DATA chunk
1483 * with the earliest outstanding TSN
1484 * for that address, restart T3-rtx
1485 * timer for that address with its
1489 forward_progress
= true;
1491 if (!tchunk
->tsn_gap_acked
) {
1493 * SFR-CACC algorithm:
1494 * 2) If the SACK contains gap acks
1495 * and the flag CHANGEOVER_ACTIVE is
1496 * set the receiver of the SACK MUST
1497 * take the following action:
1499 * B) For each TSN t being acked that
1500 * has not been acked in any SACK so
1501 * far, set cacc_saw_newack to 1 for
1502 * the destination that the TSN was
1506 sack
->num_gap_ack_blocks
&&
1507 q
->asoc
->peer
.primary_path
->cacc
.
1509 transport
->cacc
.cacc_saw_newack
1513 list_add_tail(&tchunk
->transmitted_list
,
1516 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2
1517 * M2) Each time a SACK arrives reporting
1518 * 'Stray DATA chunk(s)' record the highest TSN
1519 * reported as newly acknowledged, call this
1520 * value 'HighestTSNinSack'. A newly
1521 * acknowledged DATA chunk is one not
1522 * previously acknowledged in a SACK.
1524 * When the SCTP sender of data receives a SACK
1525 * chunk that acknowledges, for the first time,
1526 * the receipt of a DATA chunk, all the still
1527 * unacknowledged DATA chunks whose TSN is
1528 * older than that newly acknowledged DATA
1529 * chunk, are qualified as 'Stray DATA chunks'.
1531 list_add_tail(lchunk
, &tlist
);
1534 if (tchunk
->tsn_gap_acked
) {
1535 pr_debug("%s: receiver reneged on data TSN:0x%x\n",
1538 tchunk
->tsn_gap_acked
= 0;
1540 if (tchunk
->transport
)
1541 bytes_acked
-= sctp_data_size(tchunk
);
1543 /* RFC 2960 6.3.2 Retransmission Timer Rules
1545 * R4) Whenever a SACK is received missing a
1546 * TSN that was previously acknowledged via a
1547 * Gap Ack Block, start T3-rtx for the
1548 * destination address to which the DATA
1549 * chunk was originally
1550 * transmitted if it is not already running.
1555 list_add_tail(lchunk
, &tlist
);
1561 struct sctp_association
*asoc
= transport
->asoc
;
1563 /* We may have counted DATA that was migrated
1564 * to this transport due to DEL-IP operation.
1565 * Subtract those bytes, since the were never
1566 * send on this transport and shouldn't be
1567 * credited to this transport.
1569 bytes_acked
-= migrate_bytes
;
1571 /* 8.2. When an outstanding TSN is acknowledged,
1572 * the endpoint shall clear the error counter of
1573 * the destination transport address to which the
1574 * DATA chunk was last sent.
1575 * The association's overall error counter is
1578 transport
->error_count
= 0;
1579 transport
->asoc
->overall_error_count
= 0;
1580 forward_progress
= true;
1583 * While in SHUTDOWN PENDING, we may have started
1584 * the T5 shutdown guard timer after reaching the
1585 * retransmission limit. Stop that timer as soon
1586 * as the receiver acknowledged any data.
1588 if (asoc
->state
== SCTP_STATE_SHUTDOWN_PENDING
&&
1589 del_timer(&asoc
->timers
1590 [SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD
]))
1591 sctp_association_put(asoc
);
1593 /* Mark the destination transport address as
1594 * active if it is not so marked.
1596 if ((transport
->state
== SCTP_INACTIVE
||
1597 transport
->state
== SCTP_UNCONFIRMED
) &&
1598 sctp_cmp_addr_exact(&transport
->ipaddr
, saddr
)) {
1599 sctp_assoc_control_transport(
1603 SCTP_RECEIVED_SACK
);
1606 sctp_transport_raise_cwnd(transport
, sack_ctsn
,
1609 transport
->flight_size
-= bytes_acked
;
1610 if (transport
->flight_size
== 0)
1611 transport
->partial_bytes_acked
= 0;
1612 q
->outstanding_bytes
-= bytes_acked
+ migrate_bytes
;
1614 /* RFC 2960 6.1, sctpimpguide-06 2.15.2
1615 * When a sender is doing zero window probing, it
1616 * should not timeout the association if it continues
1617 * to receive new packets from the receiver. The
1618 * reason is that the receiver MAY keep its window
1619 * closed for an indefinite time.
1620 * A sender is doing zero window probing when the
1621 * receiver's advertised window is zero, and there is
1622 * only one data chunk in flight to the receiver.
1624 * Allow the association to timeout while in SHUTDOWN
1625 * PENDING or SHUTDOWN RECEIVED in case the receiver
1626 * stays in zero window mode forever.
1628 if (!q
->asoc
->peer
.rwnd
&&
1629 !list_empty(&tlist
) &&
1630 (sack_ctsn
+2 == q
->asoc
->next_tsn
) &&
1631 q
->asoc
->state
< SCTP_STATE_SHUTDOWN_PENDING
) {
1632 pr_debug("%s: sack received for zero window "
1633 "probe:%u\n", __func__
, sack_ctsn
);
1635 q
->asoc
->overall_error_count
= 0;
1636 transport
->error_count
= 0;
1640 /* RFC 2960 6.3.2 Retransmission Timer Rules
1642 * R2) Whenever all outstanding data sent to an address have
1643 * been acknowledged, turn off the T3-rtx timer of that
1646 if (!transport
->flight_size
) {
1647 if (del_timer(&transport
->T3_rtx_timer
))
1648 sctp_transport_put(transport
);
1649 } else if (restart_timer
) {
1650 if (!mod_timer(&transport
->T3_rtx_timer
,
1651 jiffies
+ transport
->rto
))
1652 sctp_transport_hold(transport
);
1655 if (forward_progress
) {
1657 sctp_transport_dst_confirm(transport
);
1661 list_splice(&tlist
, transmitted_queue
);
1664 /* Mark chunks as missing and consequently may get retransmitted. */
1665 static void sctp_mark_missing(struct sctp_outq
*q
,
1666 struct list_head
*transmitted_queue
,
1667 struct sctp_transport
*transport
,
1668 __u32 highest_new_tsn_in_sack
,
1669 int count_of_newacks
)
1671 struct sctp_chunk
*chunk
;
1673 char do_fast_retransmit
= 0;
1674 struct sctp_association
*asoc
= q
->asoc
;
1675 struct sctp_transport
*primary
= asoc
->peer
.primary_path
;
1677 list_for_each_entry(chunk
, transmitted_queue
, transmitted_list
) {
1679 tsn
= ntohl(chunk
->subh
.data_hdr
->tsn
);
1681 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all
1682 * 'Unacknowledged TSN's', if the TSN number of an
1683 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack'
1684 * value, increment the 'TSN.Missing.Report' count on that
1685 * chunk if it has NOT been fast retransmitted or marked for
1686 * fast retransmit already.
1688 if (chunk
->fast_retransmit
== SCTP_CAN_FRTX
&&
1689 !chunk
->tsn_gap_acked
&&
1690 TSN_lt(tsn
, highest_new_tsn_in_sack
)) {
1692 /* SFR-CACC may require us to skip marking
1693 * this chunk as missing.
1695 if (!transport
|| !sctp_cacc_skip(primary
,
1697 count_of_newacks
, tsn
)) {
1698 chunk
->tsn_missing_report
++;
1700 pr_debug("%s: tsn:0x%x missing counter:%d\n",
1701 __func__
, tsn
, chunk
->tsn_missing_report
);
1705 * M4) If any DATA chunk is found to have a
1706 * 'TSN.Missing.Report'
1707 * value larger than or equal to 3, mark that chunk for
1708 * retransmission and start the fast retransmit procedure.
1711 if (chunk
->tsn_missing_report
>= 3) {
1712 chunk
->fast_retransmit
= SCTP_NEED_FRTX
;
1713 do_fast_retransmit
= 1;
1718 if (do_fast_retransmit
)
1719 sctp_retransmit(q
, transport
, SCTP_RTXR_FAST_RTX
);
1721 pr_debug("%s: transport:%p, cwnd:%d, ssthresh:%d, "
1722 "flight_size:%d, pba:%d\n", __func__
, transport
,
1723 transport
->cwnd
, transport
->ssthresh
,
1724 transport
->flight_size
, transport
->partial_bytes_acked
);
1728 /* Is the given TSN acked by this packet? */
1729 static int sctp_acked(struct sctp_sackhdr
*sack
, __u32 tsn
)
1732 sctp_sack_variable_t
*frags
;
1733 __u16 tsn_offset
, blocks
;
1734 __u32 ctsn
= ntohl(sack
->cum_tsn_ack
);
1736 if (TSN_lte(tsn
, ctsn
))
1739 /* 3.3.4 Selective Acknowledgement (SACK) (3):
1742 * These fields contain the Gap Ack Blocks. They are repeated
1743 * for each Gap Ack Block up to the number of Gap Ack Blocks
1744 * defined in the Number of Gap Ack Blocks field. All DATA
1745 * chunks with TSNs greater than or equal to (Cumulative TSN
1746 * Ack + Gap Ack Block Start) and less than or equal to
1747 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack
1748 * Block are assumed to have been received correctly.
1751 frags
= sack
->variable
;
1752 blocks
= ntohs(sack
->num_gap_ack_blocks
);
1753 tsn_offset
= tsn
- ctsn
;
1754 for (i
= 0; i
< blocks
; ++i
) {
1755 if (tsn_offset
>= ntohs(frags
[i
].gab
.start
) &&
1756 tsn_offset
<= ntohs(frags
[i
].gab
.end
))
1765 static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip
*skiplist
,
1766 int nskips
, __be16 stream
)
1770 for (i
= 0; i
< nskips
; i
++) {
1771 if (skiplist
[i
].stream
== stream
)
1777 /* Create and add a fwdtsn chunk to the outq's control queue if needed. */
1778 static void sctp_generate_fwdtsn(struct sctp_outq
*q
, __u32 ctsn
)
1780 struct sctp_association
*asoc
= q
->asoc
;
1781 struct sctp_chunk
*ftsn_chunk
= NULL
;
1782 struct sctp_fwdtsn_skip ftsn_skip_arr
[10];
1786 struct sctp_chunk
*chunk
;
1787 struct list_head
*lchunk
, *temp
;
1789 if (!asoc
->peer
.prsctp_capable
)
1792 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the
1795 * If (Advanced.Peer.Ack.Point < SackCumAck), then update
1796 * Advanced.Peer.Ack.Point to be equal to SackCumAck.
1798 if (TSN_lt(asoc
->adv_peer_ack_point
, ctsn
))
1799 asoc
->adv_peer_ack_point
= ctsn
;
1801 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point"
1802 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as
1803 * the chunk next in the out-queue space is marked as "abandoned" as
1804 * shown in the following example:
1806 * Assuming that a SACK arrived with the Cumulative TSN ACK 102
1807 * and the Advanced.Peer.Ack.Point is updated to this value:
1809 * out-queue at the end of ==> out-queue after Adv.Ack.Point
1810 * normal SACK processing local advancement
1812 * Adv.Ack.Pt-> 102 acked 102 acked
1813 * 103 abandoned 103 abandoned
1814 * 104 abandoned Adv.Ack.P-> 104 abandoned
1816 * 106 acked 106 acked
1819 * In this example, the data sender successfully advanced the
1820 * "Advanced.Peer.Ack.Point" from 102 to 104 locally.
1822 list_for_each_safe(lchunk
, temp
, &q
->abandoned
) {
1823 chunk
= list_entry(lchunk
, struct sctp_chunk
,
1825 tsn
= ntohl(chunk
->subh
.data_hdr
->tsn
);
1827 /* Remove any chunks in the abandoned queue that are acked by
1830 if (TSN_lte(tsn
, ctsn
)) {
1831 list_del_init(lchunk
);
1832 sctp_chunk_free(chunk
);
1834 if (TSN_lte(tsn
, asoc
->adv_peer_ack_point
+1)) {
1835 asoc
->adv_peer_ack_point
= tsn
;
1836 if (chunk
->chunk_hdr
->flags
&
1837 SCTP_DATA_UNORDERED
)
1839 skip_pos
= sctp_get_skip_pos(&ftsn_skip_arr
[0],
1841 chunk
->subh
.data_hdr
->stream
);
1842 ftsn_skip_arr
[skip_pos
].stream
=
1843 chunk
->subh
.data_hdr
->stream
;
1844 ftsn_skip_arr
[skip_pos
].ssn
=
1845 chunk
->subh
.data_hdr
->ssn
;
1846 if (skip_pos
== nskips
)
1855 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point"
1856 * is greater than the Cumulative TSN ACK carried in the received
1857 * SACK, the data sender MUST send the data receiver a FORWARD TSN
1858 * chunk containing the latest value of the
1859 * "Advanced.Peer.Ack.Point".
1861 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD
1862 * list each stream and sequence number in the forwarded TSN. This
1863 * information will enable the receiver to easily find any
1864 * stranded TSN's waiting on stream reorder queues. Each stream
1865 * SHOULD only be reported once; this means that if multiple
1866 * abandoned messages occur in the same stream then only the
1867 * highest abandoned stream sequence number is reported. If the
1868 * total size of the FORWARD TSN does NOT fit in a single MTU then
1869 * the sender of the FORWARD TSN SHOULD lower the
1870 * Advanced.Peer.Ack.Point to the last TSN that will fit in a
1873 if (asoc
->adv_peer_ack_point
> ctsn
)
1874 ftsn_chunk
= sctp_make_fwdtsn(asoc
, asoc
->adv_peer_ack_point
,
1875 nskips
, &ftsn_skip_arr
[0]);
1878 list_add_tail(&ftsn_chunk
->list
, &q
->control_chunk_list
);
1879 SCTP_INC_STATS(sock_net(asoc
->base
.sk
), SCTP_MIB_OUTCTRLCHUNKS
);