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 struct sctp_stream_out
*streamout
;
358 if (!SCTP_PR_PRIO_ENABLED(chk
->sinfo
.sinfo_flags
) ||
359 chk
->sinfo
.sinfo_timetolive
<= sinfo
->sinfo_timetolive
)
362 list_del_init(&chk
->transmitted_list
);
363 sctp_insert_list(&asoc
->outqueue
.abandoned
,
364 &chk
->transmitted_list
);
366 streamout
= &asoc
->stream
.out
[chk
->sinfo
.sinfo_stream
];
367 asoc
->sent_cnt_removable
--;
368 asoc
->abandoned_sent
[SCTP_PR_INDEX(PRIO
)]++;
369 streamout
->abandoned_sent
[SCTP_PR_INDEX(PRIO
)]++;
371 if (!chk
->tsn_gap_acked
) {
373 chk
->transport
->flight_size
-=
375 asoc
->outqueue
.outstanding_bytes
-= sctp_data_size(chk
);
378 msg_len
-= SCTP_DATA_SNDSIZE(chk
) +
379 sizeof(struct sk_buff
) +
380 sizeof(struct sctp_chunk
);
388 static int sctp_prsctp_prune_unsent(struct sctp_association
*asoc
,
389 struct sctp_sndrcvinfo
*sinfo
, int msg_len
)
391 struct sctp_outq
*q
= &asoc
->outqueue
;
392 struct sctp_chunk
*chk
, *temp
;
394 list_for_each_entry_safe(chk
, temp
, &q
->out_chunk_list
, list
) {
395 if (!SCTP_PR_PRIO_ENABLED(chk
->sinfo
.sinfo_flags
) ||
396 chk
->sinfo
.sinfo_timetolive
<= sinfo
->sinfo_timetolive
)
399 list_del_init(&chk
->list
);
400 q
->out_qlen
-= chk
->skb
->len
;
401 asoc
->sent_cnt_removable
--;
402 asoc
->abandoned_unsent
[SCTP_PR_INDEX(PRIO
)]++;
403 if (chk
->sinfo
.sinfo_stream
< asoc
->stream
.outcnt
) {
404 struct sctp_stream_out
*streamout
=
405 &asoc
->stream
.out
[chk
->sinfo
.sinfo_stream
];
407 streamout
->abandoned_unsent
[SCTP_PR_INDEX(PRIO
)]++;
410 msg_len
-= SCTP_DATA_SNDSIZE(chk
) +
411 sizeof(struct sk_buff
) +
412 sizeof(struct sctp_chunk
);
413 sctp_chunk_free(chk
);
421 /* Abandon the chunks according their priorities */
422 void sctp_prsctp_prune(struct sctp_association
*asoc
,
423 struct sctp_sndrcvinfo
*sinfo
, int msg_len
)
425 struct sctp_transport
*transport
;
427 if (!asoc
->peer
.prsctp_capable
|| !asoc
->sent_cnt_removable
)
430 msg_len
= sctp_prsctp_prune_sent(asoc
, sinfo
,
431 &asoc
->outqueue
.retransmit
,
436 list_for_each_entry(transport
, &asoc
->peer
.transport_addr_list
,
438 msg_len
= sctp_prsctp_prune_sent(asoc
, sinfo
,
439 &transport
->transmitted
,
445 sctp_prsctp_prune_unsent(asoc
, sinfo
, msg_len
);
448 /* Mark all the eligible packets on a transport for retransmission. */
449 void sctp_retransmit_mark(struct sctp_outq
*q
,
450 struct sctp_transport
*transport
,
453 struct list_head
*lchunk
, *ltemp
;
454 struct sctp_chunk
*chunk
;
456 /* Walk through the specified transmitted queue. */
457 list_for_each_safe(lchunk
, ltemp
, &transport
->transmitted
) {
458 chunk
= list_entry(lchunk
, struct sctp_chunk
,
461 /* If the chunk is abandoned, move it to abandoned list. */
462 if (sctp_chunk_abandoned(chunk
)) {
463 list_del_init(lchunk
);
464 sctp_insert_list(&q
->abandoned
, lchunk
);
466 /* If this chunk has not been previousely acked,
467 * stop considering it 'outstanding'. Our peer
468 * will most likely never see it since it will
469 * not be retransmitted
471 if (!chunk
->tsn_gap_acked
) {
472 if (chunk
->transport
)
473 chunk
->transport
->flight_size
-=
474 sctp_data_size(chunk
);
475 q
->outstanding_bytes
-= sctp_data_size(chunk
);
476 q
->asoc
->peer
.rwnd
+= sctp_data_size(chunk
);
481 /* If we are doing retransmission due to a timeout or pmtu
482 * discovery, only the chunks that are not yet acked should
483 * be added to the retransmit queue.
485 if ((reason
== SCTP_RTXR_FAST_RTX
&&
486 (chunk
->fast_retransmit
== SCTP_NEED_FRTX
)) ||
487 (reason
!= SCTP_RTXR_FAST_RTX
&& !chunk
->tsn_gap_acked
)) {
488 /* RFC 2960 6.2.1 Processing a Received SACK
490 * C) Any time a DATA chunk is marked for
491 * retransmission (via either T3-rtx timer expiration
492 * (Section 6.3.3) or via fast retransmit
493 * (Section 7.2.4)), add the data size of those
494 * chunks to the rwnd.
496 q
->asoc
->peer
.rwnd
+= sctp_data_size(chunk
);
497 q
->outstanding_bytes
-= sctp_data_size(chunk
);
498 if (chunk
->transport
)
499 transport
->flight_size
-= sctp_data_size(chunk
);
501 /* sctpimpguide-05 Section 2.8.2
502 * M5) If a T3-rtx timer expires, the
503 * 'TSN.Missing.Report' of all affected TSNs is set
506 chunk
->tsn_missing_report
= 0;
508 /* If a chunk that is being used for RTT measurement
509 * has to be retransmitted, we cannot use this chunk
510 * anymore for RTT measurements. Reset rto_pending so
511 * that a new RTT measurement is started when a new
512 * data chunk is sent.
514 if (chunk
->rtt_in_progress
) {
515 chunk
->rtt_in_progress
= 0;
516 transport
->rto_pending
= 0;
519 /* Move the chunk to the retransmit queue. The chunks
520 * on the retransmit queue are always kept in order.
522 list_del_init(lchunk
);
523 sctp_insert_list(&q
->retransmit
, lchunk
);
527 pr_debug("%s: transport:%p, reason:%d, cwnd:%d, ssthresh:%d, "
528 "flight_size:%d, pba:%d\n", __func__
, transport
, reason
,
529 transport
->cwnd
, transport
->ssthresh
, transport
->flight_size
,
530 transport
->partial_bytes_acked
);
533 /* Mark all the eligible packets on a transport for retransmission and force
536 void sctp_retransmit(struct sctp_outq
*q
, struct sctp_transport
*transport
,
537 enum sctp_retransmit_reason reason
)
539 struct net
*net
= sock_net(q
->asoc
->base
.sk
);
542 case SCTP_RTXR_T3_RTX
:
543 SCTP_INC_STATS(net
, SCTP_MIB_T3_RETRANSMITS
);
544 sctp_transport_lower_cwnd(transport
, SCTP_LOWER_CWND_T3_RTX
);
545 /* Update the retran path if the T3-rtx timer has expired for
546 * the current retran path.
548 if (transport
== transport
->asoc
->peer
.retran_path
)
549 sctp_assoc_update_retran_path(transport
->asoc
);
550 transport
->asoc
->rtx_data_chunks
+=
551 transport
->asoc
->unack_data
;
553 case SCTP_RTXR_FAST_RTX
:
554 SCTP_INC_STATS(net
, SCTP_MIB_FAST_RETRANSMITS
);
555 sctp_transport_lower_cwnd(transport
, SCTP_LOWER_CWND_FAST_RTX
);
558 case SCTP_RTXR_PMTUD
:
559 SCTP_INC_STATS(net
, SCTP_MIB_PMTUD_RETRANSMITS
);
561 case SCTP_RTXR_T1_RTX
:
562 SCTP_INC_STATS(net
, SCTP_MIB_T1_RETRANSMITS
);
563 transport
->asoc
->init_retries
++;
569 sctp_retransmit_mark(q
, transport
, reason
);
571 /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination,
572 * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by
573 * following the procedures outlined in C1 - C5.
575 if (reason
== SCTP_RTXR_T3_RTX
)
576 sctp_generate_fwdtsn(q
, q
->asoc
->ctsn_ack_point
);
578 /* Flush the queues only on timeout, since fast_rtx is only
579 * triggered during sack processing and the queue
580 * will be flushed at the end.
582 if (reason
!= SCTP_RTXR_FAST_RTX
)
583 sctp_outq_flush(q
, /* rtx_timeout */ 1, GFP_ATOMIC
);
587 * Transmit DATA chunks on the retransmit queue. Upon return from
588 * sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which
589 * need to be transmitted by the caller.
590 * We assume that pkt->transport has already been set.
592 * The return value is a normal kernel error return value.
594 static int sctp_outq_flush_rtx(struct sctp_outq
*q
, struct sctp_packet
*pkt
,
595 int rtx_timeout
, int *start_timer
)
597 struct sctp_transport
*transport
= pkt
->transport
;
598 struct sctp_chunk
*chunk
, *chunk1
;
599 struct list_head
*lqueue
;
600 enum sctp_xmit status
;
606 lqueue
= &q
->retransmit
;
607 fast_rtx
= q
->fast_rtx
;
609 /* This loop handles time-out retransmissions, fast retransmissions,
610 * and retransmissions due to opening of whindow.
612 * RFC 2960 6.3.3 Handle T3-rtx Expiration
614 * E3) Determine how many of the earliest (i.e., lowest TSN)
615 * outstanding DATA chunks for the address for which the
616 * T3-rtx has expired will fit into a single packet, subject
617 * to the MTU constraint for the path corresponding to the
618 * destination transport address to which the retransmission
619 * is being sent (this may be different from the address for
620 * which the timer expires [see Section 6.4]). Call this value
621 * K. Bundle and retransmit those K DATA chunks in a single
622 * packet to the destination endpoint.
624 * [Just to be painfully clear, if we are retransmitting
625 * because a timeout just happened, we should send only ONE
626 * packet of retransmitted data.]
628 * For fast retransmissions we also send only ONE packet. However,
629 * if we are just flushing the queue due to open window, we'll
630 * try to send as much as possible.
632 list_for_each_entry_safe(chunk
, chunk1
, lqueue
, transmitted_list
) {
633 /* If the chunk is abandoned, move it to abandoned list. */
634 if (sctp_chunk_abandoned(chunk
)) {
635 list_del_init(&chunk
->transmitted_list
);
636 sctp_insert_list(&q
->abandoned
,
637 &chunk
->transmitted_list
);
641 /* Make sure that Gap Acked TSNs are not retransmitted. A
642 * simple approach is just to move such TSNs out of the
643 * way and into a 'transmitted' queue and skip to the
646 if (chunk
->tsn_gap_acked
) {
647 list_move_tail(&chunk
->transmitted_list
,
648 &transport
->transmitted
);
652 /* If we are doing fast retransmit, ignore non-fast_rtransmit
655 if (fast_rtx
&& !chunk
->fast_retransmit
)
659 /* Attempt to append this chunk to the packet. */
660 status
= sctp_packet_append_chunk(pkt
, chunk
);
663 case SCTP_XMIT_PMTU_FULL
:
664 if (!pkt
->has_data
&& !pkt
->has_cookie_echo
) {
665 /* If this packet did not contain DATA then
666 * retransmission did not happen, so do it
667 * again. We'll ignore the error here since
668 * control chunks are already freed so there
669 * is nothing we can do.
671 sctp_packet_transmit(pkt
, GFP_ATOMIC
);
675 /* Send this packet. */
676 error
= sctp_packet_transmit(pkt
, GFP_ATOMIC
);
678 /* If we are retransmitting, we should only
679 * send a single packet.
680 * Otherwise, try appending this chunk again.
682 if (rtx_timeout
|| fast_rtx
)
687 /* Bundle next chunk in the next round. */
690 case SCTP_XMIT_RWND_FULL
:
691 /* Send this packet. */
692 error
= sctp_packet_transmit(pkt
, GFP_ATOMIC
);
694 /* Stop sending DATA as there is no more room
700 case SCTP_XMIT_DELAY
:
701 /* Send this packet. */
702 error
= sctp_packet_transmit(pkt
, GFP_ATOMIC
);
704 /* Stop sending DATA because of nagle delay. */
709 /* The append was successful, so add this chunk to
710 * the transmitted list.
712 list_move_tail(&chunk
->transmitted_list
,
713 &transport
->transmitted
);
715 /* Mark the chunk as ineligible for fast retransmit
716 * after it is retransmitted.
718 if (chunk
->fast_retransmit
== SCTP_NEED_FRTX
)
719 chunk
->fast_retransmit
= SCTP_DONT_FRTX
;
721 q
->asoc
->stats
.rtxchunks
++;
725 /* Set the timer if there were no errors */
726 if (!error
&& !timer
)
733 /* If we are here due to a retransmit timeout or a fast
734 * retransmit and if there are any chunks left in the retransmit
735 * queue that could not fit in the PMTU sized packet, they need
736 * to be marked as ineligible for a subsequent fast retransmit.
738 if (rtx_timeout
|| fast_rtx
) {
739 list_for_each_entry(chunk1
, lqueue
, transmitted_list
) {
740 if (chunk1
->fast_retransmit
== SCTP_NEED_FRTX
)
741 chunk1
->fast_retransmit
= SCTP_DONT_FRTX
;
745 *start_timer
= timer
;
747 /* Clear fast retransmit hint */
754 /* Cork the outqueue so queued chunks are really queued. */
755 void sctp_outq_uncork(struct sctp_outq
*q
, gfp_t gfp
)
760 sctp_outq_flush(q
, 0, gfp
);
765 * Try to flush an outqueue.
767 * Description: Send everything in q which we legally can, subject to
768 * congestion limitations.
769 * * Note: This function can be called from multiple contexts so appropriate
770 * locking concerns must be made. Today we use the sock lock to protect
773 static void sctp_outq_flush(struct sctp_outq
*q
, int rtx_timeout
, gfp_t gfp
)
775 struct sctp_packet
*packet
;
776 struct sctp_packet singleton
;
777 struct sctp_association
*asoc
= q
->asoc
;
778 __u16 sport
= asoc
->base
.bind_addr
.port
;
779 __u16 dport
= asoc
->peer
.port
;
780 __u32 vtag
= asoc
->peer
.i
.init_tag
;
781 struct sctp_transport
*transport
= NULL
;
782 struct sctp_transport
*new_transport
;
783 struct sctp_chunk
*chunk
, *tmp
;
784 enum sctp_xmit status
;
789 /* These transports have chunks to send. */
790 struct list_head transport_list
;
791 struct list_head
*ltransport
;
793 INIT_LIST_HEAD(&transport_list
);
799 * When bundling control chunks with DATA chunks, an
800 * endpoint MUST place control chunks first in the outbound
801 * SCTP packet. The transmitter MUST transmit DATA chunks
802 * within a SCTP packet in increasing order of TSN.
806 list_for_each_entry_safe(chunk
, tmp
, &q
->control_chunk_list
, list
) {
808 * F1) This means that until such time as the ASCONF
809 * containing the add is acknowledged, the sender MUST
810 * NOT use the new IP address as a source for ANY SCTP
811 * packet except on carrying an ASCONF Chunk.
813 if (asoc
->src_out_of_asoc_ok
&&
814 chunk
->chunk_hdr
->type
!= SCTP_CID_ASCONF
)
817 list_del_init(&chunk
->list
);
819 /* Pick the right transport to use. */
820 new_transport
= chunk
->transport
;
822 if (!new_transport
) {
824 * If we have a prior transport pointer, see if
825 * the destination address of the chunk
826 * matches the destination address of the
827 * current transport. If not a match, then
828 * try to look up the transport with a given
829 * destination address. We do this because
830 * after processing ASCONFs, we may have new
831 * transports created.
834 sctp_cmp_addr_exact(&chunk
->dest
,
836 new_transport
= transport
;
838 new_transport
= sctp_assoc_lookup_paddr(asoc
,
841 /* if we still don't have a new transport, then
842 * use the current active path.
845 new_transport
= asoc
->peer
.active_path
;
846 } else if ((new_transport
->state
== SCTP_INACTIVE
) ||
847 (new_transport
->state
== SCTP_UNCONFIRMED
) ||
848 (new_transport
->state
== SCTP_PF
)) {
849 /* If the chunk is Heartbeat or Heartbeat Ack,
850 * send it to chunk->transport, even if it's
853 * 3.3.6 Heartbeat Acknowledgement:
855 * A HEARTBEAT ACK is always sent to the source IP
856 * address of the IP datagram containing the
857 * HEARTBEAT chunk to which this ack is responding.
860 * ASCONF_ACKs also must be sent to the source.
862 if (chunk
->chunk_hdr
->type
!= SCTP_CID_HEARTBEAT
&&
863 chunk
->chunk_hdr
->type
!= SCTP_CID_HEARTBEAT_ACK
&&
864 chunk
->chunk_hdr
->type
!= SCTP_CID_ASCONF_ACK
)
865 new_transport
= asoc
->peer
.active_path
;
868 /* Are we switching transports?
869 * Take care of transport locks.
871 if (new_transport
!= transport
) {
872 transport
= new_transport
;
873 if (list_empty(&transport
->send_ready
)) {
874 list_add_tail(&transport
->send_ready
,
877 packet
= &transport
->packet
;
878 sctp_packet_config(packet
, vtag
,
879 asoc
->peer
.ecn_capable
);
882 switch (chunk
->chunk_hdr
->type
) {
886 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN
887 * COMPLETE with any other chunks. [Send them immediately.]
890 case SCTP_CID_INIT_ACK
:
891 case SCTP_CID_SHUTDOWN_COMPLETE
:
892 sctp_packet_init(&singleton
, transport
, sport
, dport
);
893 sctp_packet_config(&singleton
, vtag
, 0);
894 sctp_packet_append_chunk(&singleton
, chunk
);
895 error
= sctp_packet_transmit(&singleton
, gfp
);
897 asoc
->base
.sk
->sk_err
= -error
;
903 if (sctp_test_T_bit(chunk
)) {
904 packet
->vtag
= asoc
->c
.my_vtag
;
906 /* The following chunks are "response" chunks, i.e.
907 * they are generated in response to something we
908 * received. If we are sending these, then we can
909 * send only 1 packet containing these chunks.
911 case SCTP_CID_HEARTBEAT_ACK
:
912 case SCTP_CID_SHUTDOWN_ACK
:
913 case SCTP_CID_COOKIE_ACK
:
914 case SCTP_CID_COOKIE_ECHO
:
916 case SCTP_CID_ECN_CWR
:
917 case SCTP_CID_ASCONF_ACK
:
922 case SCTP_CID_HEARTBEAT
:
923 case SCTP_CID_SHUTDOWN
:
924 case SCTP_CID_ECN_ECNE
:
925 case SCTP_CID_ASCONF
:
926 case SCTP_CID_FWD_TSN
:
927 case SCTP_CID_RECONF
:
928 status
= sctp_packet_transmit_chunk(packet
, chunk
,
930 if (status
!= SCTP_XMIT_OK
) {
931 /* put the chunk back */
932 list_add(&chunk
->list
, &q
->control_chunk_list
);
936 asoc
->stats
.octrlchunks
++;
937 /* PR-SCTP C5) If a FORWARD TSN is sent, the
938 * sender MUST assure that at least one T3-rtx
941 if (chunk
->chunk_hdr
->type
== SCTP_CID_FWD_TSN
) {
942 sctp_transport_reset_t3_rtx(transport
);
943 transport
->last_time_sent
= jiffies
;
946 if (chunk
== asoc
->strreset_chunk
)
947 sctp_transport_reset_reconf_timer(transport
);
952 /* We built a chunk with an illegal type! */
957 if (q
->asoc
->src_out_of_asoc_ok
)
960 /* Is it OK to send data chunks? */
961 switch (asoc
->state
) {
962 case SCTP_STATE_COOKIE_ECHOED
:
963 /* Only allow bundling when this packet has a COOKIE-ECHO
966 if (!packet
|| !packet
->has_cookie_echo
)
970 case SCTP_STATE_ESTABLISHED
:
971 case SCTP_STATE_SHUTDOWN_PENDING
:
972 case SCTP_STATE_SHUTDOWN_RECEIVED
:
974 * RFC 2960 6.1 Transmission of DATA Chunks
976 * C) When the time comes for the sender to transmit,
977 * before sending new DATA chunks, the sender MUST
978 * first transmit any outstanding DATA chunks which
979 * are marked for retransmission (limited by the
982 if (!list_empty(&q
->retransmit
)) {
983 if (asoc
->peer
.retran_path
->state
== SCTP_UNCONFIRMED
)
985 if (transport
== asoc
->peer
.retran_path
)
988 /* Switch transports & prepare the packet. */
990 transport
= asoc
->peer
.retran_path
;
992 if (list_empty(&transport
->send_ready
)) {
993 list_add_tail(&transport
->send_ready
,
997 packet
= &transport
->packet
;
998 sctp_packet_config(packet
, vtag
,
999 asoc
->peer
.ecn_capable
);
1001 error
= sctp_outq_flush_rtx(q
, packet
,
1002 rtx_timeout
, &start_timer
);
1004 asoc
->base
.sk
->sk_err
= -error
;
1007 sctp_transport_reset_t3_rtx(transport
);
1008 transport
->last_time_sent
= jiffies
;
1011 /* This can happen on COOKIE-ECHO resend. Only
1012 * one chunk can get bundled with a COOKIE-ECHO.
1014 if (packet
->has_cookie_echo
)
1015 goto sctp_flush_out
;
1017 /* Don't send new data if there is still data
1018 * waiting to retransmit.
1020 if (!list_empty(&q
->retransmit
))
1021 goto sctp_flush_out
;
1024 /* Apply Max.Burst limitation to the current transport in
1025 * case it will be used for new data. We are going to
1026 * rest it before we return, but we want to apply the limit
1027 * to the currently queued data.
1030 sctp_transport_burst_limited(transport
);
1032 /* Finally, transmit new packets. */
1033 while ((chunk
= sctp_outq_dequeue_data(q
)) != NULL
) {
1034 __u32 sid
= ntohs(chunk
->subh
.data_hdr
->stream
);
1036 /* RFC 2960 6.5 Every DATA chunk MUST carry a valid
1037 * stream identifier.
1039 if (chunk
->sinfo
.sinfo_stream
>= asoc
->stream
.outcnt
) {
1041 /* Mark as failed send. */
1042 sctp_chunk_fail(chunk
, SCTP_ERROR_INV_STRM
);
1043 if (asoc
->peer
.prsctp_capable
&&
1044 SCTP_PR_PRIO_ENABLED(chunk
->sinfo
.sinfo_flags
))
1045 asoc
->sent_cnt_removable
--;
1046 sctp_chunk_free(chunk
);
1050 /* Has this chunk expired? */
1051 if (sctp_chunk_abandoned(chunk
)) {
1052 sctp_chunk_fail(chunk
, 0);
1053 sctp_chunk_free(chunk
);
1057 if (asoc
->stream
.out
[sid
].state
== SCTP_STREAM_CLOSED
) {
1058 sctp_outq_head_data(q
, chunk
);
1059 goto sctp_flush_out
;
1062 /* If there is a specified transport, use it.
1063 * Otherwise, we want to use the active path.
1065 new_transport
= chunk
->transport
;
1066 if (!new_transport
||
1067 ((new_transport
->state
== SCTP_INACTIVE
) ||
1068 (new_transport
->state
== SCTP_UNCONFIRMED
) ||
1069 (new_transport
->state
== SCTP_PF
)))
1070 new_transport
= asoc
->peer
.active_path
;
1071 if (new_transport
->state
== SCTP_UNCONFIRMED
) {
1072 WARN_ONCE(1, "Attempt to send packet on unconfirmed path.");
1073 sctp_chunk_fail(chunk
, 0);
1074 sctp_chunk_free(chunk
);
1078 /* Change packets if necessary. */
1079 if (new_transport
!= transport
) {
1080 transport
= new_transport
;
1082 /* Schedule to have this transport's
1085 if (list_empty(&transport
->send_ready
)) {
1086 list_add_tail(&transport
->send_ready
,
1090 packet
= &transport
->packet
;
1091 sctp_packet_config(packet
, vtag
,
1092 asoc
->peer
.ecn_capable
);
1093 /* We've switched transports, so apply the
1094 * Burst limit to the new transport.
1096 sctp_transport_burst_limited(transport
);
1099 pr_debug("%s: outq:%p, chunk:%p[%s], tx-tsn:0x%x skb->head:%p "
1101 __func__
, q
, chunk
, chunk
&& chunk
->chunk_hdr
?
1102 sctp_cname(SCTP_ST_CHUNK(chunk
->chunk_hdr
->type
)) :
1103 "illegal chunk", ntohl(chunk
->subh
.data_hdr
->tsn
),
1104 chunk
->skb
? chunk
->skb
->head
: NULL
, chunk
->skb
?
1105 refcount_read(&chunk
->skb
->users
) : -1);
1107 /* Add the chunk to the packet. */
1108 status
= sctp_packet_transmit_chunk(packet
, chunk
, 0, gfp
);
1111 case SCTP_XMIT_PMTU_FULL
:
1112 case SCTP_XMIT_RWND_FULL
:
1113 case SCTP_XMIT_DELAY
:
1114 /* We could not append this chunk, so put
1115 * the chunk back on the output queue.
1117 pr_debug("%s: could not transmit tsn:0x%x, status:%d\n",
1118 __func__
, ntohl(chunk
->subh
.data_hdr
->tsn
),
1121 sctp_outq_head_data(q
, chunk
);
1122 goto sctp_flush_out
;
1125 /* The sender is in the SHUTDOWN-PENDING state,
1126 * The sender MAY set the I-bit in the DATA
1129 if (asoc
->state
== SCTP_STATE_SHUTDOWN_PENDING
)
1130 chunk
->chunk_hdr
->flags
|= SCTP_DATA_SACK_IMM
;
1131 if (chunk
->chunk_hdr
->flags
& SCTP_DATA_UNORDERED
)
1132 asoc
->stats
.ouodchunks
++;
1134 asoc
->stats
.oodchunks
++;
1142 /* BUG: We assume that the sctp_packet_transmit()
1143 * call below will succeed all the time and add the
1144 * chunk to the transmitted list and restart the
1146 * It is possible that the call can fail under OOM
1149 * Is this really a problem? Won't this behave
1152 list_add_tail(&chunk
->transmitted_list
,
1153 &transport
->transmitted
);
1155 sctp_transport_reset_t3_rtx(transport
);
1156 transport
->last_time_sent
= jiffies
;
1158 /* Only let one DATA chunk get bundled with a
1159 * COOKIE-ECHO chunk.
1161 if (packet
->has_cookie_echo
)
1162 goto sctp_flush_out
;
1173 /* Before returning, examine all the transports touched in
1174 * this call. Right now, we bluntly force clear all the
1175 * transports. Things might change after we implement Nagle.
1176 * But such an examination is still required.
1180 while ((ltransport
= sctp_list_dequeue(&transport_list
)) != NULL
) {
1181 struct sctp_transport
*t
= list_entry(ltransport
,
1182 struct sctp_transport
,
1184 packet
= &t
->packet
;
1185 if (!sctp_packet_empty(packet
)) {
1186 error
= sctp_packet_transmit(packet
, gfp
);
1188 asoc
->base
.sk
->sk_err
= -error
;
1191 /* Clear the burst limited state, if any */
1192 sctp_transport_burst_reset(t
);
1196 /* Update unack_data based on the incoming SACK chunk */
1197 static void sctp_sack_update_unack_data(struct sctp_association
*assoc
,
1198 struct sctp_sackhdr
*sack
)
1200 union sctp_sack_variable
*frags
;
1204 unack_data
= assoc
->next_tsn
- assoc
->ctsn_ack_point
- 1;
1206 frags
= sack
->variable
;
1207 for (i
= 0; i
< ntohs(sack
->num_gap_ack_blocks
); i
++) {
1208 unack_data
-= ((ntohs(frags
[i
].gab
.end
) -
1209 ntohs(frags
[i
].gab
.start
) + 1));
1212 assoc
->unack_data
= unack_data
;
1215 /* This is where we REALLY process a SACK.
1217 * Process the SACK against the outqueue. Mostly, this just frees
1218 * things off the transmitted queue.
1220 int sctp_outq_sack(struct sctp_outq
*q
, struct sctp_chunk
*chunk
)
1222 struct sctp_association
*asoc
= q
->asoc
;
1223 struct sctp_sackhdr
*sack
= chunk
->subh
.sack_hdr
;
1224 struct sctp_transport
*transport
;
1225 struct sctp_chunk
*tchunk
= NULL
;
1226 struct list_head
*lchunk
, *transport_list
, *temp
;
1227 union sctp_sack_variable
*frags
= sack
->variable
;
1228 __u32 sack_ctsn
, ctsn
, tsn
;
1229 __u32 highest_tsn
, highest_new_tsn
;
1231 unsigned int outstanding
;
1232 struct sctp_transport
*primary
= asoc
->peer
.primary_path
;
1233 int count_of_newacks
= 0;
1237 /* Grab the association's destination address list. */
1238 transport_list
= &asoc
->peer
.transport_addr_list
;
1240 sack_ctsn
= ntohl(sack
->cum_tsn_ack
);
1241 gap_ack_blocks
= ntohs(sack
->num_gap_ack_blocks
);
1242 asoc
->stats
.gapcnt
+= gap_ack_blocks
;
1244 * SFR-CACC algorithm:
1245 * On receipt of a SACK the sender SHOULD execute the
1246 * following statements.
1248 * 1) If the cumulative ack in the SACK passes next tsn_at_change
1249 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be
1250 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for
1252 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE
1253 * is set the receiver of the SACK MUST take the following actions:
1255 * A) Initialize the cacc_saw_newack to 0 for all destination
1258 * Only bother if changeover_active is set. Otherwise, this is
1259 * totally suboptimal to do on every SACK.
1261 if (primary
->cacc
.changeover_active
) {
1262 u8 clear_cycling
= 0;
1264 if (TSN_lte(primary
->cacc
.next_tsn_at_change
, sack_ctsn
)) {
1265 primary
->cacc
.changeover_active
= 0;
1269 if (clear_cycling
|| gap_ack_blocks
) {
1270 list_for_each_entry(transport
, transport_list
,
1273 transport
->cacc
.cycling_changeover
= 0;
1275 transport
->cacc
.cacc_saw_newack
= 0;
1280 /* Get the highest TSN in the sack. */
1281 highest_tsn
= sack_ctsn
;
1283 highest_tsn
+= ntohs(frags
[gap_ack_blocks
- 1].gab
.end
);
1285 if (TSN_lt(asoc
->highest_sacked
, highest_tsn
))
1286 asoc
->highest_sacked
= highest_tsn
;
1288 highest_new_tsn
= sack_ctsn
;
1290 /* Run through the retransmit queue. Credit bytes received
1291 * and free those chunks that we can.
1293 sctp_check_transmitted(q
, &q
->retransmit
, NULL
, NULL
, sack
, &highest_new_tsn
);
1295 /* Run through the transmitted queue.
1296 * Credit bytes received and free those chunks which we can.
1298 * This is a MASSIVE candidate for optimization.
1300 list_for_each_entry(transport
, transport_list
, transports
) {
1301 sctp_check_transmitted(q
, &transport
->transmitted
,
1302 transport
, &chunk
->source
, sack
,
1305 * SFR-CACC algorithm:
1306 * C) Let count_of_newacks be the number of
1307 * destinations for which cacc_saw_newack is set.
1309 if (transport
->cacc
.cacc_saw_newack
)
1313 /* Move the Cumulative TSN Ack Point if appropriate. */
1314 if (TSN_lt(asoc
->ctsn_ack_point
, sack_ctsn
)) {
1315 asoc
->ctsn_ack_point
= sack_ctsn
;
1319 if (gap_ack_blocks
) {
1321 if (asoc
->fast_recovery
&& accum_moved
)
1322 highest_new_tsn
= highest_tsn
;
1324 list_for_each_entry(transport
, transport_list
, transports
)
1325 sctp_mark_missing(q
, &transport
->transmitted
, transport
,
1326 highest_new_tsn
, count_of_newacks
);
1329 /* Update unack_data field in the assoc. */
1330 sctp_sack_update_unack_data(asoc
, sack
);
1332 ctsn
= asoc
->ctsn_ack_point
;
1334 /* Throw away stuff rotting on the sack queue. */
1335 list_for_each_safe(lchunk
, temp
, &q
->sacked
) {
1336 tchunk
= list_entry(lchunk
, struct sctp_chunk
,
1338 tsn
= ntohl(tchunk
->subh
.data_hdr
->tsn
);
1339 if (TSN_lte(tsn
, ctsn
)) {
1340 list_del_init(&tchunk
->transmitted_list
);
1341 if (asoc
->peer
.prsctp_capable
&&
1342 SCTP_PR_PRIO_ENABLED(chunk
->sinfo
.sinfo_flags
))
1343 asoc
->sent_cnt_removable
--;
1344 sctp_chunk_free(tchunk
);
1348 /* ii) Set rwnd equal to the newly received a_rwnd minus the
1349 * number of bytes still outstanding after processing the
1350 * Cumulative TSN Ack and the Gap Ack Blocks.
1353 sack_a_rwnd
= ntohl(sack
->a_rwnd
);
1354 asoc
->peer
.zero_window_announced
= !sack_a_rwnd
;
1355 outstanding
= q
->outstanding_bytes
;
1357 if (outstanding
< sack_a_rwnd
)
1358 sack_a_rwnd
-= outstanding
;
1362 asoc
->peer
.rwnd
= sack_a_rwnd
;
1364 sctp_generate_fwdtsn(q
, sack_ctsn
);
1366 pr_debug("%s: sack cumulative tsn ack:0x%x\n", __func__
, sack_ctsn
);
1367 pr_debug("%s: cumulative tsn ack of assoc:%p is 0x%x, "
1368 "advertised peer ack point:0x%x\n", __func__
, asoc
, ctsn
,
1369 asoc
->adv_peer_ack_point
);
1371 return sctp_outq_is_empty(q
);
1374 /* Is the outqueue empty?
1375 * The queue is empty when we have not pending data, no in-flight data
1376 * and nothing pending retransmissions.
1378 int sctp_outq_is_empty(const struct sctp_outq
*q
)
1380 return q
->out_qlen
== 0 && q
->outstanding_bytes
== 0 &&
1381 list_empty(&q
->retransmit
);
1384 /********************************************************************
1385 * 2nd Level Abstractions
1386 ********************************************************************/
1388 /* Go through a transport's transmitted list or the association's retransmit
1389 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked.
1390 * The retransmit list will not have an associated transport.
1392 * I added coherent debug information output. --xguo
1394 * Instead of printing 'sacked' or 'kept' for each TSN on the
1395 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5.
1396 * KEPT TSN6-TSN7, etc.
1398 static void sctp_check_transmitted(struct sctp_outq
*q
,
1399 struct list_head
*transmitted_queue
,
1400 struct sctp_transport
*transport
,
1401 union sctp_addr
*saddr
,
1402 struct sctp_sackhdr
*sack
,
1403 __u32
*highest_new_tsn_in_sack
)
1405 struct list_head
*lchunk
;
1406 struct sctp_chunk
*tchunk
;
1407 struct list_head tlist
;
1411 __u8 restart_timer
= 0;
1412 int bytes_acked
= 0;
1413 int migrate_bytes
= 0;
1414 bool forward_progress
= false;
1416 sack_ctsn
= ntohl(sack
->cum_tsn_ack
);
1418 INIT_LIST_HEAD(&tlist
);
1420 /* The while loop will skip empty transmitted queues. */
1421 while (NULL
!= (lchunk
= sctp_list_dequeue(transmitted_queue
))) {
1422 tchunk
= list_entry(lchunk
, struct sctp_chunk
,
1425 if (sctp_chunk_abandoned(tchunk
)) {
1426 /* Move the chunk to abandoned list. */
1427 sctp_insert_list(&q
->abandoned
, lchunk
);
1429 /* If this chunk has not been acked, stop
1430 * considering it as 'outstanding'.
1432 if (!tchunk
->tsn_gap_acked
) {
1433 if (tchunk
->transport
)
1434 tchunk
->transport
->flight_size
-=
1435 sctp_data_size(tchunk
);
1436 q
->outstanding_bytes
-= sctp_data_size(tchunk
);
1441 tsn
= ntohl(tchunk
->subh
.data_hdr
->tsn
);
1442 if (sctp_acked(sack
, tsn
)) {
1443 /* If this queue is the retransmit queue, the
1444 * retransmit timer has already reclaimed
1445 * the outstanding bytes for this chunk, so only
1446 * count bytes associated with a transport.
1449 /* If this chunk is being used for RTT
1450 * measurement, calculate the RTT and update
1451 * the RTO using this value.
1453 * 6.3.1 C5) Karn's algorithm: RTT measurements
1454 * MUST NOT be made using packets that were
1455 * retransmitted (and thus for which it is
1456 * ambiguous whether the reply was for the
1457 * first instance of the packet or a later
1460 if (!tchunk
->tsn_gap_acked
&&
1461 !sctp_chunk_retransmitted(tchunk
) &&
1462 tchunk
->rtt_in_progress
) {
1463 tchunk
->rtt_in_progress
= 0;
1464 rtt
= jiffies
- tchunk
->sent_at
;
1465 sctp_transport_update_rto(transport
,
1470 /* If the chunk hasn't been marked as ACKED,
1471 * mark it and account bytes_acked if the
1472 * chunk had a valid transport (it will not
1473 * have a transport if ASCONF had deleted it
1474 * while DATA was outstanding).
1476 if (!tchunk
->tsn_gap_acked
) {
1477 tchunk
->tsn_gap_acked
= 1;
1478 if (TSN_lt(*highest_new_tsn_in_sack
, tsn
))
1479 *highest_new_tsn_in_sack
= tsn
;
1480 bytes_acked
+= sctp_data_size(tchunk
);
1481 if (!tchunk
->transport
)
1482 migrate_bytes
+= sctp_data_size(tchunk
);
1483 forward_progress
= true;
1486 if (TSN_lte(tsn
, sack_ctsn
)) {
1487 /* RFC 2960 6.3.2 Retransmission Timer Rules
1489 * R3) Whenever a SACK is received
1490 * that acknowledges the DATA chunk
1491 * with the earliest outstanding TSN
1492 * for that address, restart T3-rtx
1493 * timer for that address with its
1497 forward_progress
= true;
1499 if (!tchunk
->tsn_gap_acked
) {
1501 * SFR-CACC algorithm:
1502 * 2) If the SACK contains gap acks
1503 * and the flag CHANGEOVER_ACTIVE is
1504 * set the receiver of the SACK MUST
1505 * take the following action:
1507 * B) For each TSN t being acked that
1508 * has not been acked in any SACK so
1509 * far, set cacc_saw_newack to 1 for
1510 * the destination that the TSN was
1514 sack
->num_gap_ack_blocks
&&
1515 q
->asoc
->peer
.primary_path
->cacc
.
1517 transport
->cacc
.cacc_saw_newack
1521 list_add_tail(&tchunk
->transmitted_list
,
1524 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2
1525 * M2) Each time a SACK arrives reporting
1526 * 'Stray DATA chunk(s)' record the highest TSN
1527 * reported as newly acknowledged, call this
1528 * value 'HighestTSNinSack'. A newly
1529 * acknowledged DATA chunk is one not
1530 * previously acknowledged in a SACK.
1532 * When the SCTP sender of data receives a SACK
1533 * chunk that acknowledges, for the first time,
1534 * the receipt of a DATA chunk, all the still
1535 * unacknowledged DATA chunks whose TSN is
1536 * older than that newly acknowledged DATA
1537 * chunk, are qualified as 'Stray DATA chunks'.
1539 list_add_tail(lchunk
, &tlist
);
1542 if (tchunk
->tsn_gap_acked
) {
1543 pr_debug("%s: receiver reneged on data TSN:0x%x\n",
1546 tchunk
->tsn_gap_acked
= 0;
1548 if (tchunk
->transport
)
1549 bytes_acked
-= sctp_data_size(tchunk
);
1551 /* RFC 2960 6.3.2 Retransmission Timer Rules
1553 * R4) Whenever a SACK is received missing a
1554 * TSN that was previously acknowledged via a
1555 * Gap Ack Block, start T3-rtx for the
1556 * destination address to which the DATA
1557 * chunk was originally
1558 * transmitted if it is not already running.
1563 list_add_tail(lchunk
, &tlist
);
1569 struct sctp_association
*asoc
= transport
->asoc
;
1571 /* We may have counted DATA that was migrated
1572 * to this transport due to DEL-IP operation.
1573 * Subtract those bytes, since the were never
1574 * send on this transport and shouldn't be
1575 * credited to this transport.
1577 bytes_acked
-= migrate_bytes
;
1579 /* 8.2. When an outstanding TSN is acknowledged,
1580 * the endpoint shall clear the error counter of
1581 * the destination transport address to which the
1582 * DATA chunk was last sent.
1583 * The association's overall error counter is
1586 transport
->error_count
= 0;
1587 transport
->asoc
->overall_error_count
= 0;
1588 forward_progress
= true;
1591 * While in SHUTDOWN PENDING, we may have started
1592 * the T5 shutdown guard timer after reaching the
1593 * retransmission limit. Stop that timer as soon
1594 * as the receiver acknowledged any data.
1596 if (asoc
->state
== SCTP_STATE_SHUTDOWN_PENDING
&&
1597 del_timer(&asoc
->timers
1598 [SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD
]))
1599 sctp_association_put(asoc
);
1601 /* Mark the destination transport address as
1602 * active if it is not so marked.
1604 if ((transport
->state
== SCTP_INACTIVE
||
1605 transport
->state
== SCTP_UNCONFIRMED
) &&
1606 sctp_cmp_addr_exact(&transport
->ipaddr
, saddr
)) {
1607 sctp_assoc_control_transport(
1611 SCTP_RECEIVED_SACK
);
1614 sctp_transport_raise_cwnd(transport
, sack_ctsn
,
1617 transport
->flight_size
-= bytes_acked
;
1618 if (transport
->flight_size
== 0)
1619 transport
->partial_bytes_acked
= 0;
1620 q
->outstanding_bytes
-= bytes_acked
+ migrate_bytes
;
1622 /* RFC 2960 6.1, sctpimpguide-06 2.15.2
1623 * When a sender is doing zero window probing, it
1624 * should not timeout the association if it continues
1625 * to receive new packets from the receiver. The
1626 * reason is that the receiver MAY keep its window
1627 * closed for an indefinite time.
1628 * A sender is doing zero window probing when the
1629 * receiver's advertised window is zero, and there is
1630 * only one data chunk in flight to the receiver.
1632 * Allow the association to timeout while in SHUTDOWN
1633 * PENDING or SHUTDOWN RECEIVED in case the receiver
1634 * stays in zero window mode forever.
1636 if (!q
->asoc
->peer
.rwnd
&&
1637 !list_empty(&tlist
) &&
1638 (sack_ctsn
+2 == q
->asoc
->next_tsn
) &&
1639 q
->asoc
->state
< SCTP_STATE_SHUTDOWN_PENDING
) {
1640 pr_debug("%s: sack received for zero window "
1641 "probe:%u\n", __func__
, sack_ctsn
);
1643 q
->asoc
->overall_error_count
= 0;
1644 transport
->error_count
= 0;
1648 /* RFC 2960 6.3.2 Retransmission Timer Rules
1650 * R2) Whenever all outstanding data sent to an address have
1651 * been acknowledged, turn off the T3-rtx timer of that
1654 if (!transport
->flight_size
) {
1655 if (del_timer(&transport
->T3_rtx_timer
))
1656 sctp_transport_put(transport
);
1657 } else if (restart_timer
) {
1658 if (!mod_timer(&transport
->T3_rtx_timer
,
1659 jiffies
+ transport
->rto
))
1660 sctp_transport_hold(transport
);
1663 if (forward_progress
) {
1665 sctp_transport_dst_confirm(transport
);
1669 list_splice(&tlist
, transmitted_queue
);
1672 /* Mark chunks as missing and consequently may get retransmitted. */
1673 static void sctp_mark_missing(struct sctp_outq
*q
,
1674 struct list_head
*transmitted_queue
,
1675 struct sctp_transport
*transport
,
1676 __u32 highest_new_tsn_in_sack
,
1677 int count_of_newacks
)
1679 struct sctp_chunk
*chunk
;
1681 char do_fast_retransmit
= 0;
1682 struct sctp_association
*asoc
= q
->asoc
;
1683 struct sctp_transport
*primary
= asoc
->peer
.primary_path
;
1685 list_for_each_entry(chunk
, transmitted_queue
, transmitted_list
) {
1687 tsn
= ntohl(chunk
->subh
.data_hdr
->tsn
);
1689 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all
1690 * 'Unacknowledged TSN's', if the TSN number of an
1691 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack'
1692 * value, increment the 'TSN.Missing.Report' count on that
1693 * chunk if it has NOT been fast retransmitted or marked for
1694 * fast retransmit already.
1696 if (chunk
->fast_retransmit
== SCTP_CAN_FRTX
&&
1697 !chunk
->tsn_gap_acked
&&
1698 TSN_lt(tsn
, highest_new_tsn_in_sack
)) {
1700 /* SFR-CACC may require us to skip marking
1701 * this chunk as missing.
1703 if (!transport
|| !sctp_cacc_skip(primary
,
1705 count_of_newacks
, tsn
)) {
1706 chunk
->tsn_missing_report
++;
1708 pr_debug("%s: tsn:0x%x missing counter:%d\n",
1709 __func__
, tsn
, chunk
->tsn_missing_report
);
1713 * M4) If any DATA chunk is found to have a
1714 * 'TSN.Missing.Report'
1715 * value larger than or equal to 3, mark that chunk for
1716 * retransmission and start the fast retransmit procedure.
1719 if (chunk
->tsn_missing_report
>= 3) {
1720 chunk
->fast_retransmit
= SCTP_NEED_FRTX
;
1721 do_fast_retransmit
= 1;
1726 if (do_fast_retransmit
)
1727 sctp_retransmit(q
, transport
, SCTP_RTXR_FAST_RTX
);
1729 pr_debug("%s: transport:%p, cwnd:%d, ssthresh:%d, "
1730 "flight_size:%d, pba:%d\n", __func__
, transport
,
1731 transport
->cwnd
, transport
->ssthresh
,
1732 transport
->flight_size
, transport
->partial_bytes_acked
);
1736 /* Is the given TSN acked by this packet? */
1737 static int sctp_acked(struct sctp_sackhdr
*sack
, __u32 tsn
)
1739 __u32 ctsn
= ntohl(sack
->cum_tsn_ack
);
1740 union sctp_sack_variable
*frags
;
1741 __u16 tsn_offset
, blocks
;
1744 if (TSN_lte(tsn
, ctsn
))
1747 /* 3.3.4 Selective Acknowledgement (SACK) (3):
1750 * These fields contain the Gap Ack Blocks. They are repeated
1751 * for each Gap Ack Block up to the number of Gap Ack Blocks
1752 * defined in the Number of Gap Ack Blocks field. All DATA
1753 * chunks with TSNs greater than or equal to (Cumulative TSN
1754 * Ack + Gap Ack Block Start) and less than or equal to
1755 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack
1756 * Block are assumed to have been received correctly.
1759 frags
= sack
->variable
;
1760 blocks
= ntohs(sack
->num_gap_ack_blocks
);
1761 tsn_offset
= tsn
- ctsn
;
1762 for (i
= 0; i
< blocks
; ++i
) {
1763 if (tsn_offset
>= ntohs(frags
[i
].gab
.start
) &&
1764 tsn_offset
<= ntohs(frags
[i
].gab
.end
))
1773 static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip
*skiplist
,
1774 int nskips
, __be16 stream
)
1778 for (i
= 0; i
< nskips
; i
++) {
1779 if (skiplist
[i
].stream
== stream
)
1785 /* Create and add a fwdtsn chunk to the outq's control queue if needed. */
1786 static void sctp_generate_fwdtsn(struct sctp_outq
*q
, __u32 ctsn
)
1788 struct sctp_association
*asoc
= q
->asoc
;
1789 struct sctp_chunk
*ftsn_chunk
= NULL
;
1790 struct sctp_fwdtsn_skip ftsn_skip_arr
[10];
1794 struct sctp_chunk
*chunk
;
1795 struct list_head
*lchunk
, *temp
;
1797 if (!asoc
->peer
.prsctp_capable
)
1800 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the
1803 * If (Advanced.Peer.Ack.Point < SackCumAck), then update
1804 * Advanced.Peer.Ack.Point to be equal to SackCumAck.
1806 if (TSN_lt(asoc
->adv_peer_ack_point
, ctsn
))
1807 asoc
->adv_peer_ack_point
= ctsn
;
1809 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point"
1810 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as
1811 * the chunk next in the out-queue space is marked as "abandoned" as
1812 * shown in the following example:
1814 * Assuming that a SACK arrived with the Cumulative TSN ACK 102
1815 * and the Advanced.Peer.Ack.Point is updated to this value:
1817 * out-queue at the end of ==> out-queue after Adv.Ack.Point
1818 * normal SACK processing local advancement
1820 * Adv.Ack.Pt-> 102 acked 102 acked
1821 * 103 abandoned 103 abandoned
1822 * 104 abandoned Adv.Ack.P-> 104 abandoned
1824 * 106 acked 106 acked
1827 * In this example, the data sender successfully advanced the
1828 * "Advanced.Peer.Ack.Point" from 102 to 104 locally.
1830 list_for_each_safe(lchunk
, temp
, &q
->abandoned
) {
1831 chunk
= list_entry(lchunk
, struct sctp_chunk
,
1833 tsn
= ntohl(chunk
->subh
.data_hdr
->tsn
);
1835 /* Remove any chunks in the abandoned queue that are acked by
1838 if (TSN_lte(tsn
, ctsn
)) {
1839 list_del_init(lchunk
);
1840 sctp_chunk_free(chunk
);
1842 if (TSN_lte(tsn
, asoc
->adv_peer_ack_point
+1)) {
1843 asoc
->adv_peer_ack_point
= tsn
;
1844 if (chunk
->chunk_hdr
->flags
&
1845 SCTP_DATA_UNORDERED
)
1847 skip_pos
= sctp_get_skip_pos(&ftsn_skip_arr
[0],
1849 chunk
->subh
.data_hdr
->stream
);
1850 ftsn_skip_arr
[skip_pos
].stream
=
1851 chunk
->subh
.data_hdr
->stream
;
1852 ftsn_skip_arr
[skip_pos
].ssn
=
1853 chunk
->subh
.data_hdr
->ssn
;
1854 if (skip_pos
== nskips
)
1863 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point"
1864 * is greater than the Cumulative TSN ACK carried in the received
1865 * SACK, the data sender MUST send the data receiver a FORWARD TSN
1866 * chunk containing the latest value of the
1867 * "Advanced.Peer.Ack.Point".
1869 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD
1870 * list each stream and sequence number in the forwarded TSN. This
1871 * information will enable the receiver to easily find any
1872 * stranded TSN's waiting on stream reorder queues. Each stream
1873 * SHOULD only be reported once; this means that if multiple
1874 * abandoned messages occur in the same stream then only the
1875 * highest abandoned stream sequence number is reported. If the
1876 * total size of the FORWARD TSN does NOT fit in a single MTU then
1877 * the sender of the FORWARD TSN SHOULD lower the
1878 * Advanced.Peer.Ack.Point to the last TSN that will fit in a
1881 if (asoc
->adv_peer_ack_point
> ctsn
)
1882 ftsn_chunk
= sctp_make_fwdtsn(asoc
, asoc
->adv_peer_ack_point
,
1883 nskips
, &ftsn_skip_arr
[0]);
1886 list_add_tail(&ftsn_chunk
->list
, &q
->control_chunk_list
);
1887 SCTP_INC_STATS(sock_net(asoc
->base
.sk
), SCTP_MIB_OUTCTRLCHUNKS
);