1 /* SCTP kernel reference 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.
6 *
7 * This file is part of the SCTP kernel reference Implementation
8 *
9 * These functions implement the sctp_outq class. The outqueue handles
10 * bundling and queueing of outgoing SCTP chunks.
11 *
12 * The SCTP reference implementation is free software;
13 * you can redistribute it and/or modify it under the terms of
14 * the GNU General Public License as published by
15 * the Free Software Foundation; either version 2, or (at your option)
16 * any later version.
17 *
18 * The SCTP reference implementation is distributed in the hope that it
19 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
20 * ************************
21 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
22 * See the GNU General Public License for more details.
23 *
24 * You should have received a copy of the GNU General Public License
25 * along with GNU CC; see the file COPYING. If not, write to
26 * the Free Software Foundation, 59 Temple Place - Suite 330,
27 * Boston, MA 02111-1307, USA.
28 *
29 * Please send any bug reports or fixes you make to the
30 * email address(es):
31 * lksctp developers <lksctp-developers@lists.sourceforge.net>
32 *
33 * Or submit a bug report through the following website:
34 * http://www.sf.net/projects/lksctp
35 *
36 * Written or modified by:
37 * La Monte H.P. Yarroll <piggy@acm.org>
38 * Karl Knutson <karl@athena.chicago.il.us>
39 * Perry Melange <pmelange@null.cc.uic.edu>
40 * Xingang Guo <xingang.guo@intel.com>
41 * Hui Huang <hui.huang@nokia.com>
42 * Sridhar Samudrala <sri@us.ibm.com>
43 * Jon Grimm <jgrimm@us.ibm.com>
44 *
45 * Any bugs reported given to us we will try to fix... any fixes shared will
46 * be incorporated into the next SCTP release.
47 */
48
49 #include <linux/types.h>
50 #include <linux/list.h> /* For struct list_head */
51 #include <linux/socket.h>
52 #include <linux/ip.h>
53 #include <net/sock.h> /* For skb_set_owner_w */
54
55 #include <net/sctp/sctp.h>
56 #include <net/sctp/sm.h>
57
58 /* Declare internal functions here. */
59 static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn);
60 static void sctp_check_transmitted(struct sctp_outq *q,
61 struct list_head *transmitted_queue,
62 struct sctp_transport *transport,
63 struct sctp_sackhdr *sack,
64 __u32 highest_new_tsn);
65
66 static void sctp_mark_missing(struct sctp_outq *q,
67 struct list_head *transmitted_queue,
68 struct sctp_transport *transport,
69 __u32 highest_new_tsn,
70 int count_of_newacks);
71
72 static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 sack_ctsn);
73
74 /* Add data to the front of the queue. */
sctp_outq_head_data(struct sctp_outq * q,struct sctp_chunk * ch)75 static inline void sctp_outq_head_data(struct sctp_outq *q,
76 struct sctp_chunk *ch)
77 {
78 __skb_queue_head(&q->out, (struct sk_buff *)ch);
79 q->out_qlen += ch->skb->len;
80 return;
81 }
82
83 /* Take data from the front of the queue. */
sctp_outq_dequeue_data(struct sctp_outq * q)84 static inline struct sctp_chunk *sctp_outq_dequeue_data(struct sctp_outq *q)
85 {
86 struct sctp_chunk *ch;
87 ch = (struct sctp_chunk *)__skb_dequeue(&q->out);
88 if (ch)
89 q->out_qlen -= ch->skb->len;
90 return ch;
91 }
92 /* Add data chunk to the end of the queue. */
sctp_outq_tail_data(struct sctp_outq * q,struct sctp_chunk * ch)93 static inline void sctp_outq_tail_data(struct sctp_outq *q,
94 struct sctp_chunk *ch)
95 {
96 __skb_queue_tail(&q->out, (struct sk_buff *)ch);
97 q->out_qlen += ch->skb->len;
98 return;
99 }
100
101 /* Insert a chunk behind chunk 'pos'. */
sctp_outq_insert_data(struct sctp_outq * q,struct sctp_chunk * ch,struct sctp_chunk * pos)102 static inline void sctp_outq_insert_data(struct sctp_outq *q,
103 struct sctp_chunk *ch,
104 struct sctp_chunk *pos)
105 {
106 __skb_insert((struct sk_buff *)ch, (struct sk_buff *)pos->prev,
107 (struct sk_buff *)pos, pos->list);
108 q->out_qlen += ch->skb->len;
109 }
110
111 /*
112 * SFR-CACC algorithm:
113 * D) If count_of_newacks is greater than or equal to 2
114 * and t was not sent to the current primary then the
115 * sender MUST NOT increment missing report count for t.
116 */
sctp_cacc_skip_3_1_d(struct sctp_transport * primary,struct sctp_transport * transport,int count_of_newacks)117 static inline int sctp_cacc_skip_3_1_d(struct sctp_transport *primary,
118 struct sctp_transport *transport,
119 int count_of_newacks)
120 {
121 if (count_of_newacks >=2 && transport != primary)
122 return 1;
123 return 0;
124 }
125
126 /*
127 * SFR-CACC algorithm:
128 * F) If count_of_newacks is less than 2, let d be the
129 * destination to which t was sent. If cacc_saw_newack
130 * is 0 for destination d, then the sender MUST NOT
131 * increment missing report count for t.
132 */
sctp_cacc_skip_3_1_f(struct sctp_transport * transport,int count_of_newacks)133 static inline int sctp_cacc_skip_3_1_f(struct sctp_transport *transport,
134 int count_of_newacks)
135 {
136 if (count_of_newacks < 2 && !transport->cacc.cacc_saw_newack)
137 return 1;
138 return 0;
139 }
140
141 /*
142 * SFR-CACC algorithm:
143 * 3.1) If CYCLING_CHANGEOVER is 0, the sender SHOULD
144 * execute steps C, D, F.
145 *
146 * C has been implemented in sctp_outq_sack
147 */
sctp_cacc_skip_3_1(struct sctp_transport * primary,struct sctp_transport * transport,int count_of_newacks)148 static inline int sctp_cacc_skip_3_1(struct sctp_transport *primary,
149 struct sctp_transport *transport,
150 int count_of_newacks)
151 {
152 if (!primary->cacc.cycling_changeover) {
153 if (sctp_cacc_skip_3_1_d(primary, transport, count_of_newacks))
154 return 1;
155 if (sctp_cacc_skip_3_1_f(transport, count_of_newacks))
156 return 1;
157 return 0;
158 }
159 return 0;
160 }
161
162 /*
163 * SFR-CACC algorithm:
164 * 3.2) Else if CYCLING_CHANGEOVER is 1, and t is less
165 * than next_tsn_at_change of the current primary, then
166 * the sender MUST NOT increment missing report count
167 * for t.
168 */
sctp_cacc_skip_3_2(struct sctp_transport * primary,__u32 tsn)169 static inline int sctp_cacc_skip_3_2(struct sctp_transport *primary, __u32 tsn)
170 {
171 if (primary->cacc.cycling_changeover &&
172 TSN_lt(tsn, primary->cacc.next_tsn_at_change))
173 return 1;
174 return 0;
175 }
176
177 /*
178 * SFR-CACC algorithm:
179 * 3) If the missing report count for TSN t is to be
180 * incremented according to [RFC2960] and
181 * [SCTP_STEWART-2002], and CHANGEOVER_ACTIVE is set,
182 * then the sender MUST futher execute steps 3.1 and
183 * 3.2 to determine if the missing report count for
184 * TSN t SHOULD NOT be incremented.
185 *
186 * 3.3) If 3.1 and 3.2 do not dictate that the missing
187 * report count for t should not be incremented, then
188 * the sender SOULD increment missing report count for
189 * t (according to [RFC2960] and [SCTP_STEWART_2002]).
190 */
sctp_cacc_skip(struct sctp_transport * primary,struct sctp_transport * transport,int count_of_newacks,__u32 tsn)191 static inline int sctp_cacc_skip(struct sctp_transport *primary,
192 struct sctp_transport *transport,
193 int count_of_newacks,
194 __u32 tsn)
195 {
196 if (primary->cacc.changeover_active &&
197 (sctp_cacc_skip_3_1(primary, transport, count_of_newacks)
198 || sctp_cacc_skip_3_2(primary, tsn)))
199 return 1;
200 return 0;
201 }
202
203 /* Initialize an existing sctp_outq. This does the boring stuff.
204 * You still need to define handlers if you really want to DO
205 * something with this structure...
206 */
sctp_outq_init(struct sctp_association * asoc,struct sctp_outq * q)207 void sctp_outq_init(struct sctp_association *asoc, struct sctp_outq *q)
208 {
209 q->asoc = asoc;
210 skb_queue_head_init(&q->out);
211 skb_queue_head_init(&q->control);
212 INIT_LIST_HEAD(&q->retransmit);
213 INIT_LIST_HEAD(&q->sacked);
214 INIT_LIST_HEAD(&q->abandoned);
215
216 q->outstanding_bytes = 0;
217 q->empty = 1;
218 q->cork = 0;
219
220 q->malloced = 0;
221 q->out_qlen = 0;
222 }
223
224 /* Free the outqueue structure and any related pending chunks.
225 */
sctp_outq_teardown(struct sctp_outq * q)226 void sctp_outq_teardown(struct sctp_outq *q)
227 {
228 struct sctp_transport *transport;
229 struct list_head *lchunk, *pos, *temp;
230 struct sctp_chunk *chunk;
231
232 /* Throw away unacknowledged chunks. */
233 list_for_each(pos, &q->asoc->peer.transport_addr_list) {
234 transport = list_entry(pos, struct sctp_transport, transports);
235 while ((lchunk = sctp_list_dequeue(&transport->transmitted)) != NULL) {
236 chunk = list_entry(lchunk, struct sctp_chunk,
237 transmitted_list);
238 /* Mark as part of a failed message. */
239 sctp_chunk_fail(chunk, q->error);
240 sctp_chunk_free(chunk);
241 }
242 }
243
244 /* Throw away chunks that have been gap ACKed. */
245 list_for_each_safe(lchunk, temp, &q->sacked) {
246 list_del_init(lchunk);
247 chunk = list_entry(lchunk, struct sctp_chunk,
248 transmitted_list);
249 sctp_chunk_fail(chunk, q->error);
250 sctp_chunk_free(chunk);
251 }
252
253 /* Throw away any chunks in the retransmit queue. */
254 list_for_each_safe(lchunk, temp, &q->retransmit) {
255 list_del_init(lchunk);
256 chunk = list_entry(lchunk, struct sctp_chunk,
257 transmitted_list);
258 sctp_chunk_fail(chunk, q->error);
259 sctp_chunk_free(chunk);
260 }
261
262 /* Throw away any chunks that are in the abandoned queue. */
263 list_for_each_safe(lchunk, temp, &q->abandoned) {
264 list_del_init(lchunk);
265 chunk = list_entry(lchunk, struct sctp_chunk,
266 transmitted_list);
267 sctp_chunk_fail(chunk, q->error);
268 sctp_chunk_free(chunk);
269 }
270
271 /* Throw away any leftover data chunks. */
272 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) {
273
274 /* Mark as send failure. */
275 sctp_chunk_fail(chunk, q->error);
276 sctp_chunk_free(chunk);
277 }
278
279 q->error = 0;
280
281 /* Throw away any leftover control chunks. */
282 while ((chunk = (struct sctp_chunk *) skb_dequeue(&q->control)) != NULL)
283 sctp_chunk_free(chunk);
284 }
285
286 /* Free the outqueue structure and any related pending chunks. */
sctp_outq_free(struct sctp_outq * q)287 void sctp_outq_free(struct sctp_outq *q)
288 {
289 /* Throw away leftover chunks. */
290 sctp_outq_teardown(q);
291
292 /* If we were kmalloc()'d, free the memory. */
293 if (q->malloced)
294 kfree(q);
295 }
296
297 /* Put a new chunk in an sctp_outq. */
sctp_outq_tail(struct sctp_outq * q,struct sctp_chunk * chunk)298 int sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk)
299 {
300 int error = 0;
301
302 SCTP_DEBUG_PRINTK("sctp_outq_tail(%p, %p[%s])\n",
303 q, chunk, chunk && chunk->chunk_hdr ?
304 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type))
305 : "Illegal Chunk");
306
307 /* If it is data, queue it up, otherwise, send it
308 * immediately.
309 */
310 if (SCTP_CID_DATA == chunk->chunk_hdr->type) {
311 /* Is it OK to queue data chunks? */
312 /* From 9. Termination of Association
313 *
314 * When either endpoint performs a shutdown, the
315 * association on each peer will stop accepting new
316 * data from its user and only deliver data in queue
317 * at the time of sending or receiving the SHUTDOWN
318 * chunk.
319 */
320 switch (q->asoc->state) {
321 case SCTP_STATE_EMPTY:
322 case SCTP_STATE_CLOSED:
323 case SCTP_STATE_SHUTDOWN_PENDING:
324 case SCTP_STATE_SHUTDOWN_SENT:
325 case SCTP_STATE_SHUTDOWN_RECEIVED:
326 case SCTP_STATE_SHUTDOWN_ACK_SENT:
327 /* Cannot send after transport endpoint shutdown */
328 error = -ESHUTDOWN;
329 break;
330
331 default:
332 SCTP_DEBUG_PRINTK("outqueueing (%p, %p[%s])\n",
333 q, chunk, chunk && chunk->chunk_hdr ?
334 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type))
335 : "Illegal Chunk");
336
337 sctp_outq_tail_data(q, chunk);
338 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED)
339 SCTP_INC_STATS(SctpOutUnorderChunks);
340 else
341 SCTP_INC_STATS(SctpOutOrderChunks);
342 q->empty = 0;
343 break;
344 };
345 } else {
346 __skb_queue_tail(&q->control, (struct sk_buff *) chunk);
347 SCTP_INC_STATS(SctpOutCtrlChunks);
348 }
349
350 if (error < 0)
351 return error;
352
353 if (!q->cork)
354 error = sctp_outq_flush(q, 0);
355
356 return error;
357 }
358
359 /* Insert a chunk into the sorted list based on the TSNs. The retransmit list
360 * and the abandoned list are in ascending order.
361 */
sctp_insert_list(struct list_head * head,struct list_head * new)362 static void sctp_insert_list(struct list_head *head, struct list_head *new)
363 {
364 struct list_head *pos;
365 struct sctp_chunk *nchunk, *lchunk;
366 __u32 ntsn, ltsn;
367 int done = 0;
368
369 nchunk = list_entry(new, struct sctp_chunk, transmitted_list);
370 ntsn = ntohl(nchunk->subh.data_hdr->tsn);
371
372 list_for_each(pos, head) {
373 lchunk = list_entry(pos, struct sctp_chunk, transmitted_list);
374 ltsn = ntohl(lchunk->subh.data_hdr->tsn);
375 if (TSN_lt(ntsn, ltsn)) {
376 list_add(new, pos->prev);
377 done = 1;
378 break;
379 }
380 }
381 if (!done)
382 list_add_tail(new, head);
383 }
384
385 /* Mark all the eligible packets on a transport for retransmission. */
sctp_retransmit_mark(struct sctp_outq * q,struct sctp_transport * transport,__u8 fast_retransmit)386 void sctp_retransmit_mark(struct sctp_outq *q,
387 struct sctp_transport *transport,
388 __u8 fast_retransmit)
389 {
390 struct list_head *lchunk, *ltemp;
391 struct sctp_chunk *chunk;
392
393 /* Walk through the specified transmitted queue. */
394 list_for_each_safe(lchunk, ltemp, &transport->transmitted) {
395 chunk = list_entry(lchunk, struct sctp_chunk,
396 transmitted_list);
397
398 /* If the chunk is abandoned, move it to abandoned list. */
399 if (sctp_chunk_abandoned(chunk)) {
400 list_del_init(lchunk);
401 sctp_insert_list(&q->abandoned, lchunk);
402 continue;
403 }
404
405 /* If we are doing retransmission due to a fast retransmit,
406 * only the chunk's that are marked for fast retransmit
407 * should be added to the retransmit queue. If we are doing
408 * retransmission due to a timeout or pmtu discovery, only the
409 * chunks that are not yet acked should be added to the
410 * retransmit queue.
411 */
412 if ((fast_retransmit && chunk->fast_retransmit) ||
413 (!fast_retransmit && !chunk->tsn_gap_acked)) {
414 /* RFC 2960 6.2.1 Processing a Received SACK
415 *
416 * C) Any time a DATA chunk is marked for
417 * retransmission (via either T3-rtx timer expiration
418 * (Section 6.3.3) or via fast retransmit
419 * (Section 7.2.4)), add the data size of those
420 * chunks to the rwnd.
421 */
422 q->asoc->peer.rwnd += sctp_data_size(chunk);
423 q->outstanding_bytes -= sctp_data_size(chunk);
424 transport->flight_size -= sctp_data_size(chunk);
425
426 /* sctpimpguide-05 Section 2.8.2
427 * M5) If a T3-rtx timer expires, the
428 * 'TSN.Missing.Report' of all affected TSNs is set
429 * to 0.
430 */
431 chunk->tsn_missing_report = 0;
432
433 /* If a chunk that is being used for RTT measurement
434 * has to be retransmitted, we cannot use this chunk
435 * anymore for RTT measurements. Reset rto_pending so
436 * that a new RTT measurement is started when a new
437 * data chunk is sent.
438 */
439 if (chunk->rtt_in_progress) {
440 chunk->rtt_in_progress = 0;
441 transport->rto_pending = 0;
442 }
443
444 /* Move the chunk to the retransmit queue. The chunks
445 * on the retransmit queue are always kept in order.
446 */
447 list_del_init(lchunk);
448 sctp_insert_list(&q->retransmit, lchunk);
449 }
450 }
451
452 SCTP_DEBUG_PRINTK("%s: transport: %p, fast_retransmit: %d, "
453 "cwnd: %d, ssthresh: %d, flight_size: %d, "
454 "pba: %d\n", __FUNCTION__,
455 transport, fast_retransmit,
456 transport->cwnd, transport->ssthresh,
457 transport->flight_size,
458 transport->partial_bytes_acked);
459
460 }
461
462 /* Mark all the eligible packets on a transport for retransmission and force
463 * one packet out.
464 */
sctp_retransmit(struct sctp_outq * q,struct sctp_transport * transport,sctp_retransmit_reason_t reason)465 void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport,
466 sctp_retransmit_reason_t reason)
467 {
468 int error = 0;
469 __u8 fast_retransmit = 0;
470
471 switch(reason) {
472 case SCTP_RTXR_T3_RTX:
473 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_T3_RTX);
474 /* Update the retran path if the T3-rtx timer has expired for
475 * the current retran path.
476 */
477 if (transport == transport->asoc->peer.retran_path)
478 sctp_assoc_update_retran_path(transport->asoc);
479 break;
480 case SCTP_RTXR_FAST_RTX:
481 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_FAST_RTX);
482 fast_retransmit = 1;
483 break;
484 case SCTP_RTXR_PMTUD:
485 default:
486 break;
487 }
488
489 sctp_retransmit_mark(q, transport, fast_retransmit);
490
491 /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination,
492 * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by
493 * following the procedures outlined in C1 - C5.
494 */
495 sctp_generate_fwdtsn(q, q->asoc->ctsn_ack_point);
496
497 error = sctp_outq_flush(q, /* rtx_timeout */ 1);
498
499 if (error)
500 q->asoc->base.sk->err = -error;
501 }
502
503 /*
504 * Transmit DATA chunks on the retransmit queue. Upon return from
505 * sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which
506 * need to be transmitted by the caller.
507 * We assume that pkt->transport has already been set.
508 *
509 * The return value is a normal kernel error return value.
510 */
sctp_outq_flush_rtx(struct sctp_outq * q,struct sctp_packet * pkt,int rtx_timeout,int * start_timer)511 static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt,
512 int rtx_timeout, int *start_timer)
513 {
514 struct list_head *lqueue;
515 struct list_head *lchunk, *lchunk1;
516 struct sctp_transport *transport = pkt->transport;
517 sctp_xmit_t status;
518 struct sctp_chunk *chunk, *chunk1;
519 struct sctp_association *asoc;
520 int error = 0;
521
522 asoc = q->asoc;
523 lqueue = &q->retransmit;
524
525 /* RFC 2960 6.3.3 Handle T3-rtx Expiration
526 *
527 * E3) Determine how many of the earliest (i.e., lowest TSN)
528 * outstanding DATA chunks for the address for which the
529 * T3-rtx has expired will fit into a single packet, subject
530 * to the MTU constraint for the path corresponding to the
531 * destination transport address to which the retransmission
532 * is being sent (this may be different from the address for
533 * which the timer expires [see Section 6.4]). Call this value
534 * K. Bundle and retransmit those K DATA chunks in a single
535 * packet to the destination endpoint.
536 *
537 * [Just to be painfully clear, if we are retransmitting
538 * because a timeout just happened, we should send only ONE
539 * packet of retransmitted data.]
540 */
541 lchunk = sctp_list_dequeue(lqueue);
542
543 while (lchunk) {
544 chunk = list_entry(lchunk, struct sctp_chunk,
545 transmitted_list);
546
547 /* Make sure that Gap Acked TSNs are not retransmitted. A
548 * simple approach is just to move such TSNs out of the
549 * way and into a 'transmitted' queue and skip to the
550 * next chunk.
551 */
552 if (chunk->tsn_gap_acked) {
553 list_add_tail(lchunk, &transport->transmitted);
554 lchunk = sctp_list_dequeue(lqueue);
555 continue;
556 }
557
558 /* Attempt to append this chunk to the packet. */
559 status = sctp_packet_append_chunk(pkt, chunk);
560
561 switch (status) {
562 case SCTP_XMIT_PMTU_FULL:
563 /* Send this packet. */
564 if ((error = sctp_packet_transmit(pkt)) == 0)
565 *start_timer = 1;
566
567 /* If we are retransmitting, we should only
568 * send a single packet.
569 */
570 if (rtx_timeout) {
571 list_add(lchunk, lqueue);
572 lchunk = NULL;
573 }
574
575 /* Bundle lchunk in the next round. */
576 break;
577
578 case SCTP_XMIT_RWND_FULL:
579 /* Send this packet. */
580 if ((error = sctp_packet_transmit(pkt)) == 0)
581 *start_timer = 1;
582
583 /* Stop sending DATA as there is no more room
584 * at the receiver.
585 */
586 list_add(lchunk, lqueue);
587 lchunk = NULL;
588 break;
589
590 case SCTP_XMIT_NAGLE_DELAY:
591 /* Send this packet. */
592 if ((error = sctp_packet_transmit(pkt)) == 0)
593 *start_timer = 1;
594
595 /* Stop sending DATA because of nagle delay. */
596 list_add(lchunk, lqueue);
597 lchunk = NULL;
598 break;
599
600 default:
601 /* The append was successful, so add this chunk to
602 * the transmitted list.
603 */
604 list_add_tail(lchunk, &transport->transmitted);
605
606 /* Mark the chunk as ineligible for fast retransmit
607 * after it is retransmitted.
608 */
609 chunk->fast_retransmit = 0;
610
611 *start_timer = 1;
612 q->empty = 0;
613
614 /* Retrieve a new chunk to bundle. */
615 lchunk = sctp_list_dequeue(lqueue);
616 break;
617 };
618
619 /* If we are here due to a retransmit timeout or a fast
620 * retransmit and if there are any chunks left in the retransmit
621 * queue that could not fit in the PMTU sized packet, they need * to be marked as ineligible for a subsequent fast retransmit.
622 */
623 if (rtx_timeout && !lchunk) {
624 list_for_each(lchunk1, lqueue) {
625 chunk1 = list_entry(lchunk1, struct sctp_chunk,
626 transmitted_list);
627 chunk1->fast_retransmit = 0;
628 }
629 }
630 }
631
632 return error;
633 }
634
635 /* Cork the outqueue so queued chunks are really queued. */
sctp_outq_uncork(struct sctp_outq * q)636 int sctp_outq_uncork(struct sctp_outq *q)
637 {
638 int error = 0;
639 if (q->cork) {
640 q->cork = 0;
641 error = sctp_outq_flush(q, 0);
642 }
643 return error;
644 }
645
646 /*
647 * Try to flush an outqueue.
648 *
649 * Description: Send everything in q which we legally can, subject to
650 * congestion limitations.
651 * * Note: This function can be called from multiple contexts so appropriate
652 * locking concerns must be made. Today we use the sock lock to protect
653 * this function.
654 */
sctp_outq_flush(struct sctp_outq * q,int rtx_timeout)655 int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout)
656 {
657 struct sctp_packet *packet;
658 struct sctp_packet singleton;
659 struct sctp_association *asoc = q->asoc;
660 __u16 sport = asoc->base.bind_addr.port;
661 __u16 dport = asoc->peer.port;
662 __u32 vtag = asoc->peer.i.init_tag;
663 struct sk_buff_head *queue;
664 struct sctp_transport *transport = NULL;
665 struct sctp_transport *new_transport;
666 struct sctp_chunk *chunk;
667 sctp_xmit_t status;
668 int error = 0;
669 int start_timer = 0;
670
671 /* These transports have chunks to send. */
672 struct list_head transport_list;
673 struct list_head *ltransport;
674
675 INIT_LIST_HEAD(&transport_list);
676 packet = NULL;
677
678 /*
679 * 6.10 Bundling
680 * ...
681 * When bundling control chunks with DATA chunks, an
682 * endpoint MUST place control chunks first in the outbound
683 * SCTP packet. The transmitter MUST transmit DATA chunks
684 * within a SCTP packet in increasing order of TSN.
685 * ...
686 */
687
688 queue = &q->control;
689 while ((chunk = (struct sctp_chunk *)skb_dequeue(queue)) != NULL) {
690 /* Pick the right transport to use. */
691 new_transport = chunk->transport;
692
693 if (!new_transport) {
694 new_transport = asoc->peer.active_path;
695 } else if (!new_transport->active) {
696 /* If the chunk is Heartbeat or Heartbeat Ack,
697 * send it to chunk->transport, even if it's
698 * inactive.
699 *
700 * 3.3.6 Heartbeat Acknowledgement:
701 * ...
702 * A HEARTBEAT ACK is always sent to the source IP
703 * address of the IP datagram containing the
704 * HEARTBEAT chunk to which this ack is responding.
705 * ...
706 */
707 if (chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT &&
708 chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT_ACK)
709 new_transport = asoc->peer.active_path;
710 }
711
712 /* Are we switching transports?
713 * Take care of transport locks.
714 */
715 if (new_transport != transport) {
716 transport = new_transport;
717 if (list_empty(&transport->send_ready)) {
718 list_add_tail(&transport->send_ready,
719 &transport_list);
720 }
721 packet = &transport->packet;
722 sctp_packet_config(packet, vtag,
723 asoc->peer.ecn_capable);
724 }
725
726 switch (chunk->chunk_hdr->type) {
727 /*
728 * 6.10 Bundling
729 * ...
730 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN
731 * COMPLETE with any other chunks. [Send them immediately.]
732 */
733 case SCTP_CID_INIT:
734 case SCTP_CID_INIT_ACK:
735 case SCTP_CID_SHUTDOWN_COMPLETE:
736 sctp_packet_init(&singleton, transport, sport, dport);
737 sctp_packet_config(&singleton, vtag, 0);
738 sctp_packet_append_chunk(&singleton, chunk);
739 error = sctp_packet_transmit(&singleton);
740 if (error < 0)
741 return error;
742 break;
743
744 case SCTP_CID_ABORT:
745 case SCTP_CID_SACK:
746 case SCTP_CID_HEARTBEAT:
747 case SCTP_CID_HEARTBEAT_ACK:
748 case SCTP_CID_SHUTDOWN:
749 case SCTP_CID_SHUTDOWN_ACK:
750 case SCTP_CID_ERROR:
751 case SCTP_CID_COOKIE_ECHO:
752 case SCTP_CID_COOKIE_ACK:
753 case SCTP_CID_ECN_ECNE:
754 case SCTP_CID_ECN_CWR:
755 case SCTP_CID_ASCONF:
756 case SCTP_CID_ASCONF_ACK:
757 case SCTP_CID_FWD_TSN:
758 sctp_packet_transmit_chunk(packet, chunk);
759 break;
760
761 default:
762 /* We built a chunk with an illegal type! */
763 BUG();
764 };
765 }
766
767 /* Is it OK to send data chunks? */
768 switch (asoc->state) {
769 case SCTP_STATE_COOKIE_ECHOED:
770 /* Only allow bundling when this packet has a COOKIE-ECHO
771 * chunk.
772 */
773 if (!packet || !packet->has_cookie_echo)
774 break;
775
776 /* fallthru */
777 case SCTP_STATE_ESTABLISHED:
778 case SCTP_STATE_SHUTDOWN_PENDING:
779 case SCTP_STATE_SHUTDOWN_RECEIVED:
780 /*
781 * RFC 2960 6.1 Transmission of DATA Chunks
782 *
783 * C) When the time comes for the sender to transmit,
784 * before sending new DATA chunks, the sender MUST
785 * first transmit any outstanding DATA chunks which
786 * are marked for retransmission (limited by the
787 * current cwnd).
788 */
789 if (!list_empty(&q->retransmit)) {
790 if (transport == asoc->peer.retran_path)
791 goto retran;
792
793 /* Switch transports & prepare the packet. */
794
795 transport = asoc->peer.retran_path;
796
797 if (list_empty(&transport->send_ready)) {
798 list_add_tail(&transport->send_ready,
799 &transport_list);
800 }
801
802 packet = &transport->packet;
803 sctp_packet_config(packet, vtag,
804 asoc->peer.ecn_capable);
805 retran:
806 error = sctp_outq_flush_rtx(q, packet,
807 rtx_timeout, &start_timer);
808
809 if (start_timer)
810 sctp_transport_reset_timers(transport);
811
812 /* This can happen on COOKIE-ECHO resend. Only
813 * one chunk can get bundled with a COOKIE-ECHO.
814 */
815 if (packet->has_cookie_echo)
816 goto sctp_flush_out;
817
818 /* Don't send new data if there is still data
819 * waiting to retransmit.
820 */
821 if (!list_empty(&q->retransmit))
822 goto sctp_flush_out;
823 }
824
825 /* Finally, transmit new packets. */
826 start_timer = 0;
827 queue = &q->out;
828
829 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) {
830 /* RFC 2960 6.5 Every DATA chunk MUST carry a valid
831 * stream identifier.
832 */
833 if (chunk->sinfo.sinfo_stream >=
834 asoc->c.sinit_num_ostreams) {
835
836 /* Mark as failed send. */
837 sctp_chunk_fail(chunk, SCTP_ERROR_INV_STRM);
838 sctp_chunk_free(chunk);
839 continue;
840 }
841
842 /* Has this chunk expired? */
843 if (sctp_chunk_abandoned(chunk)) {
844 sctp_chunk_fail(chunk, 0);
845 sctp_chunk_free(chunk);
846 continue;
847 }
848
849 /* If there is a specified transport, use it.
850 * Otherwise, we want to use the active path.
851 */
852 new_transport = chunk->transport;
853 if (!new_transport || !new_transport->active)
854 new_transport = asoc->peer.active_path;
855
856 /* Change packets if necessary. */
857 if (new_transport != transport) {
858 transport = new_transport;
859
860 /* Schedule to have this transport's
861 * packet flushed.
862 */
863 if (list_empty(&transport->send_ready)) {
864 list_add_tail(&transport->send_ready,
865 &transport_list);
866 }
867
868 packet = &transport->packet;
869 sctp_packet_config(packet, vtag,
870 asoc->peer.ecn_capable);
871 }
872
873 SCTP_DEBUG_PRINTK("sctp_outq_flush(%p, %p[%s]), ",
874 q, chunk,
875 chunk && chunk->chunk_hdr ?
876 sctp_cname(SCTP_ST_CHUNK(
877 chunk->chunk_hdr->type))
878 : "Illegal Chunk");
879
880 SCTP_DEBUG_PRINTK("TX TSN 0x%x skb->head "
881 "%p skb->users %d.\n",
882 ntohl(chunk->subh.data_hdr->tsn),
883 chunk->skb ?chunk->skb->head : NULL,
884 chunk->skb ?
885 atomic_read(&chunk->skb->users) : -1);
886
887 /* Add the chunk to the packet. */
888 status = sctp_packet_transmit_chunk(packet, chunk);
889
890 switch (status) {
891 case SCTP_XMIT_PMTU_FULL:
892 case SCTP_XMIT_RWND_FULL:
893 case SCTP_XMIT_NAGLE_DELAY:
894 /* We could not append this chunk, so put
895 * the chunk back on the output queue.
896 */
897 SCTP_DEBUG_PRINTK("sctp_outq_flush: could "
898 "not transmit TSN: 0x%x, status: %d\n",
899 ntohl(chunk->subh.data_hdr->tsn),
900 status);
901 sctp_outq_head_data(q, chunk);
902 goto sctp_flush_out;
903 break;
904
905 case SCTP_XMIT_OK:
906 break;
907
908 default:
909 BUG();
910 }
911
912 /* BUG: We assume that the sctp_packet_transmit()
913 * call below will succeed all the time and add the
914 * chunk to the transmitted list and restart the
915 * timers.
916 * It is possible that the call can fail under OOM
917 * conditions.
918 *
919 * Is this really a problem? Won't this behave
920 * like a lost TSN?
921 */
922 list_add_tail(&chunk->transmitted_list,
923 &transport->transmitted);
924
925 sctp_transport_reset_timers(transport);
926
927 q->empty = 0;
928
929 /* Only let one DATA chunk get bundled with a
930 * COOKIE-ECHO chunk.
931 */
932 if (packet->has_cookie_echo)
933 goto sctp_flush_out;
934 }
935 break;
936
937 default:
938 /* Do nothing. */
939 break;
940 }
941
942 sctp_flush_out:
943
944 /* Before returning, examine all the transports touched in
945 * this call. Right now, we bluntly force clear all the
946 * transports. Things might change after we implement Nagle.
947 * But such an examination is still required.
948 *
949 * --xguo
950 */
951 while ((ltransport = sctp_list_dequeue(&transport_list)) != NULL ) {
952 struct sctp_transport *t = list_entry(ltransport,
953 struct sctp_transport,
954 send_ready);
955 packet = &t->packet;
956 if (!sctp_packet_empty(packet))
957 error = sctp_packet_transmit(packet);
958 }
959
960 return error;
961 }
962
963 /* Update unack_data based on the incoming SACK chunk */
sctp_sack_update_unack_data(struct sctp_association * assoc,struct sctp_sackhdr * sack)964 static void sctp_sack_update_unack_data(struct sctp_association *assoc,
965 struct sctp_sackhdr *sack)
966 {
967 sctp_sack_variable_t *frags;
968 __u16 unack_data;
969 int i;
970
971 unack_data = assoc->next_tsn - assoc->ctsn_ack_point - 1;
972
973 frags = sack->variable;
974 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); i++) {
975 unack_data -= ((ntohs(frags[i].gab.end) -
976 ntohs(frags[i].gab.start) + 1));
977 }
978
979 assoc->unack_data = unack_data;
980 }
981
982 /* Return the highest new tsn that is acknowledged by the given SACK chunk. */
sctp_highest_new_tsn(struct sctp_sackhdr * sack,struct sctp_association * asoc)983 static __u32 sctp_highest_new_tsn(struct sctp_sackhdr *sack,
984 struct sctp_association *asoc)
985 {
986 struct list_head *ltransport, *lchunk;
987 struct sctp_transport *transport;
988 struct sctp_chunk *chunk;
989 __u32 highest_new_tsn, tsn;
990 struct list_head *transport_list = &asoc->peer.transport_addr_list;
991
992 highest_new_tsn = ntohl(sack->cum_tsn_ack);
993
994 list_for_each(ltransport, transport_list) {
995 transport = list_entry(ltransport, struct sctp_transport,
996 transports);
997 list_for_each(lchunk, &transport->transmitted) {
998 chunk = list_entry(lchunk, struct sctp_chunk,
999 transmitted_list);
1000 tsn = ntohl(chunk->subh.data_hdr->tsn);
1001
1002 if (!chunk->tsn_gap_acked &&
1003 TSN_lt(highest_new_tsn, tsn) &&
1004 sctp_acked(sack, tsn))
1005 highest_new_tsn = tsn;
1006 }
1007 }
1008
1009 return highest_new_tsn;
1010 }
1011
1012 /* This is where we REALLY process a SACK.
1013 *
1014 * Process the SACK against the outqueue. Mostly, this just frees
1015 * things off the transmitted queue.
1016 */
sctp_outq_sack(struct sctp_outq * q,struct sctp_sackhdr * sack)1017 int sctp_outq_sack(struct sctp_outq *q, struct sctp_sackhdr *sack)
1018 {
1019 struct sctp_association *asoc = q->asoc;
1020 struct sctp_transport *transport;
1021 struct sctp_chunk *tchunk = NULL;
1022 struct list_head *lchunk, *transport_list, *pos, *temp;
1023 sctp_sack_variable_t *frags = sack->variable;
1024 __u32 sack_ctsn, ctsn, tsn;
1025 __u32 highest_tsn, highest_new_tsn;
1026 __u32 sack_a_rwnd;
1027 unsigned outstanding;
1028 struct sctp_transport *primary = asoc->peer.primary_path;
1029 int count_of_newacks = 0;
1030
1031 /* Grab the association's destination address list. */
1032 transport_list = &asoc->peer.transport_addr_list;
1033
1034 sack_ctsn = ntohl(sack->cum_tsn_ack);
1035
1036 /*
1037 * SFR-CACC algorithm:
1038 * On receipt of a SACK the sender SHOULD execute the
1039 * following statements.
1040 *
1041 * 1) If the cumulative ack in the SACK passes next tsn_at_change
1042 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be
1043 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for
1044 * all destinations.
1045 */
1046 if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) {
1047 primary->cacc.changeover_active = 0;
1048 list_for_each(pos, transport_list) {
1049 transport = list_entry(pos, struct sctp_transport,
1050 transports);
1051 transport->cacc.cycling_changeover = 0;
1052 }
1053 }
1054
1055 /*
1056 * SFR-CACC algorithm:
1057 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE
1058 * is set the receiver of the SACK MUST take the following actions:
1059 *
1060 * A) Initialize the cacc_saw_newack to 0 for all destination
1061 * addresses.
1062 */
1063 if (sack->num_gap_ack_blocks > 0 &&
1064 primary->cacc.changeover_active) {
1065 list_for_each(pos, transport_list) {
1066 transport = list_entry(pos, struct sctp_transport,
1067 transports);
1068 transport->cacc.cacc_saw_newack = 0;
1069 }
1070 }
1071
1072 /* Get the highest TSN in the sack. */
1073 highest_tsn = sack_ctsn;
1074 if (sack->num_gap_ack_blocks)
1075 highest_tsn +=
1076 ntohs(frags[ntohs(sack->num_gap_ack_blocks) - 1].gab.end);
1077
1078 if (TSN_lt(asoc->highest_sacked, highest_tsn)) {
1079 highest_new_tsn = highest_tsn;
1080 asoc->highest_sacked = highest_tsn;
1081 } else {
1082 highest_new_tsn = sctp_highest_new_tsn(sack, asoc);
1083 }
1084
1085 /* Run through the retransmit queue. Credit bytes received
1086 * and free those chunks that we can.
1087 */
1088 sctp_check_transmitted(q, &q->retransmit, NULL, sack, highest_new_tsn);
1089 sctp_mark_missing(q, &q->retransmit, NULL, highest_new_tsn, 0);
1090
1091 /* Run through the transmitted queue.
1092 * Credit bytes received and free those chunks which we can.
1093 *
1094 * This is a MASSIVE candidate for optimization.
1095 */
1096 list_for_each(pos, transport_list) {
1097 transport = list_entry(pos, struct sctp_transport,
1098 transports);
1099 sctp_check_transmitted(q, &transport->transmitted,
1100 transport, sack, highest_new_tsn);
1101 /*
1102 * SFR-CACC algorithm:
1103 * C) Let count_of_newacks be the number of
1104 * destinations for which cacc_saw_newack is set.
1105 */
1106 if (transport->cacc.cacc_saw_newack)
1107 count_of_newacks ++;
1108 }
1109
1110 list_for_each(pos, transport_list) {
1111 transport = list_entry(pos, struct sctp_transport,
1112 transports);
1113 sctp_mark_missing(q, &transport->transmitted, transport,
1114 highest_new_tsn, count_of_newacks);
1115 }
1116
1117 /* Move the Cumulative TSN Ack Point if appropriate. */
1118 if (TSN_lt(asoc->ctsn_ack_point, sack_ctsn))
1119 asoc->ctsn_ack_point = sack_ctsn;
1120
1121 /* Update unack_data field in the assoc. */
1122 sctp_sack_update_unack_data(asoc, sack);
1123
1124 ctsn = asoc->ctsn_ack_point;
1125
1126 /* Throw away stuff rotting on the sack queue. */
1127 list_for_each_safe(lchunk, temp, &q->sacked) {
1128 tchunk = list_entry(lchunk, struct sctp_chunk,
1129 transmitted_list);
1130 tsn = ntohl(tchunk->subh.data_hdr->tsn);
1131 if (TSN_lte(tsn, ctsn))
1132 sctp_chunk_free(tchunk);
1133 }
1134
1135 /* ii) Set rwnd equal to the newly received a_rwnd minus the
1136 * number of bytes still outstanding after processing the
1137 * Cumulative TSN Ack and the Gap Ack Blocks.
1138 */
1139
1140 sack_a_rwnd = ntohl(sack->a_rwnd);
1141 outstanding = q->outstanding_bytes;
1142
1143 if (outstanding < sack_a_rwnd)
1144 sack_a_rwnd -= outstanding;
1145 else
1146 sack_a_rwnd = 0;
1147
1148 asoc->peer.rwnd = sack_a_rwnd;
1149
1150 sctp_generate_fwdtsn(q, sack_ctsn);
1151
1152 SCTP_DEBUG_PRINTK("%s: sack Cumulative TSN Ack is 0x%x.\n",
1153 __FUNCTION__, sack_ctsn);
1154 SCTP_DEBUG_PRINTK("%s: Cumulative TSN Ack of association, "
1155 "%p is 0x%x. Adv peer ack point: 0x%x\n",
1156 __FUNCTION__, asoc, ctsn, asoc->adv_peer_ack_point);
1157
1158 /* See if all chunks are acked.
1159 * Make sure the empty queue handler will get run later.
1160 */
1161 q->empty = skb_queue_empty(&q->out) && skb_queue_empty(&q->control) &&
1162 list_empty(&q->retransmit);
1163 if (!q->empty)
1164 goto finish;
1165
1166 list_for_each(pos, transport_list) {
1167 transport = list_entry(pos, struct sctp_transport,
1168 transports);
1169 q->empty = q->empty && list_empty(&transport->transmitted);
1170 if (!q->empty)
1171 goto finish;
1172 }
1173
1174 SCTP_DEBUG_PRINTK("sack queue is empty.\n");
1175 finish:
1176 return q->empty;
1177 }
1178
1179 /* Is the outqueue empty? */
sctp_outq_is_empty(const struct sctp_outq * q)1180 int sctp_outq_is_empty(const struct sctp_outq *q)
1181 {
1182 return q->empty;
1183 }
1184
1185 /********************************************************************
1186 * 2nd Level Abstractions
1187 ********************************************************************/
1188
1189 /* Go through a transport's transmitted list or the association's retransmit
1190 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked.
1191 * The retransmit list will not have an associated transport.
1192 *
1193 * I added coherent debug information output. --xguo
1194 *
1195 * Instead of printing 'sacked' or 'kept' for each TSN on the
1196 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5.
1197 * KEPT TSN6-TSN7, etc.
1198 */
sctp_check_transmitted(struct sctp_outq * q,struct list_head * transmitted_queue,struct sctp_transport * transport,struct sctp_sackhdr * sack,__u32 highest_new_tsn_in_sack)1199 static void sctp_check_transmitted(struct sctp_outq *q,
1200 struct list_head *transmitted_queue,
1201 struct sctp_transport *transport,
1202 struct sctp_sackhdr *sack,
1203 __u32 highest_new_tsn_in_sack)
1204 {
1205 struct list_head *lchunk;
1206 struct sctp_chunk *tchunk;
1207 struct list_head tlist;
1208 __u32 tsn;
1209 __u32 sack_ctsn;
1210 __u32 rtt;
1211 __u8 restart_timer = 0;
1212 int bytes_acked = 0;
1213
1214 /* These state variables are for coherent debug output. --xguo */
1215
1216 #if SCTP_DEBUG
1217 __u32 dbg_ack_tsn = 0; /* An ACKed TSN range starts here... */
1218 __u32 dbg_last_ack_tsn = 0; /* ...and finishes here. */
1219 __u32 dbg_kept_tsn = 0; /* An un-ACKed range starts here... */
1220 __u32 dbg_last_kept_tsn = 0; /* ...and finishes here. */
1221
1222 /* 0 : The last TSN was ACKed.
1223 * 1 : The last TSN was NOT ACKed (i.e. KEPT).
1224 * -1: We need to initialize.
1225 */
1226 int dbg_prt_state = -1;
1227 #endif /* SCTP_DEBUG */
1228
1229 sack_ctsn = ntohl(sack->cum_tsn_ack);
1230
1231 INIT_LIST_HEAD(&tlist);
1232
1233 /* The while loop will skip empty transmitted queues. */
1234 while (NULL != (lchunk = sctp_list_dequeue(transmitted_queue))) {
1235 tchunk = list_entry(lchunk, struct sctp_chunk,
1236 transmitted_list);
1237
1238 if (sctp_chunk_abandoned(tchunk)) {
1239 /* Move the chunk to abandoned list. */
1240 sctp_insert_list(&q->abandoned, lchunk);
1241 continue;
1242 }
1243
1244 tsn = ntohl(tchunk->subh.data_hdr->tsn);
1245 if (sctp_acked(sack, tsn)) {
1246 /* If this queue is the retransmit queue, the
1247 * retransmit timer has already reclaimed
1248 * the outstanding bytes for this chunk, so only
1249 * count bytes associated with a transport.
1250 */
1251 if (transport) {
1252 /* If this chunk is being used for RTT
1253 * measurement, calculate the RTT and update
1254 * the RTO using this value.
1255 *
1256 * 6.3.1 C5) Karn's algorithm: RTT measurements
1257 * MUST NOT be made using packets that were
1258 * retransmitted (and thus for which it is
1259 * ambiguous whether the reply was for the
1260 * first instance of the packet or a later
1261 * instance).
1262 */
1263 if (!tchunk->tsn_gap_acked &&
1264 !tchunk->resent &&
1265 tchunk->rtt_in_progress) {
1266 rtt = jiffies - tchunk->sent_at;
1267 sctp_transport_update_rto(transport,
1268 rtt);
1269 }
1270 }
1271 if (TSN_lte(tsn, sack_ctsn)) {
1272 /* RFC 2960 6.3.2 Retransmission Timer Rules
1273 *
1274 * R3) Whenever a SACK is received
1275 * that acknowledges the DATA chunk
1276 * with the earliest outstanding TSN
1277 * for that address, restart T3-rtx
1278 * timer for that address with its
1279 * current RTO.
1280 */
1281 restart_timer = 1;
1282
1283 if (!tchunk->tsn_gap_acked) {
1284 tchunk->tsn_gap_acked = 1;
1285 bytes_acked += sctp_data_size(tchunk);
1286 /*
1287 * SFR-CACC algorithm:
1288 * 2) If the SACK contains gap acks
1289 * and the flag CHANGEOVER_ACTIVE is
1290 * set the receiver of the SACK MUST
1291 * take the following action:
1292 *
1293 * B) For each TSN t being acked that
1294 * has not been acked in any SACK so
1295 * far, set cacc_saw_newack to 1 for
1296 * the destination that the TSN was
1297 * sent to.
1298 */
1299 if (transport &&
1300 sack->num_gap_ack_blocks &&
1301 q->asoc->peer.primary_path->cacc.
1302 changeover_active)
1303 transport->cacc.cacc_saw_newack
1304 = 1;
1305 }
1306
1307 list_add_tail(&tchunk->transmitted_list,
1308 &q->sacked);
1309 } else {
1310 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2
1311 * M2) Each time a SACK arrives reporting
1312 * 'Stray DATA chunk(s)' record the highest TSN
1313 * reported as newly acknowledged, call this
1314 * value 'HighestTSNinSack'. A newly
1315 * acknowledged DATA chunk is one not
1316 * previously acknowledged in a SACK.
1317 *
1318 * When the SCTP sender of data receives a SACK
1319 * chunk that acknowledges, for the first time,
1320 * the receipt of a DATA chunk, all the still
1321 * unacknowledged DATA chunks whose TSN is
1322 * older than that newly acknowledged DATA
1323 * chunk, are qualified as 'Stray DATA chunks'.
1324 */
1325 if (!tchunk->tsn_gap_acked) {
1326 tchunk->tsn_gap_acked = 1;
1327 bytes_acked += sctp_data_size(tchunk);
1328 }
1329 list_add_tail(lchunk, &tlist);
1330 }
1331
1332 #if SCTP_DEBUG
1333 switch (dbg_prt_state) {
1334 case 0: /* last TSN was ACKed */
1335 if (dbg_last_ack_tsn + 1 == tsn) {
1336 /* This TSN belongs to the
1337 * current ACK range.
1338 */
1339 break;
1340 }
1341
1342 if (dbg_last_ack_tsn != dbg_ack_tsn) {
1343 /* Display the end of the
1344 * current range.
1345 */
1346 SCTP_DEBUG_PRINTK("-%08x",
1347 dbg_last_ack_tsn);
1348 }
1349
1350 /* Start a new range. */
1351 SCTP_DEBUG_PRINTK(",%08x", tsn);
1352 dbg_ack_tsn = tsn;
1353 break;
1354
1355 case 1: /* The last TSN was NOT ACKed. */
1356 if (dbg_last_kept_tsn != dbg_kept_tsn) {
1357 /* Display the end of current range. */
1358 SCTP_DEBUG_PRINTK("-%08x",
1359 dbg_last_kept_tsn);
1360 }
1361
1362 SCTP_DEBUG_PRINTK("\n");
1363
1364 /* FALL THROUGH... */
1365 default:
1366 /* This is the first-ever TSN we examined. */
1367 /* Start a new range of ACK-ed TSNs. */
1368 SCTP_DEBUG_PRINTK("ACKed: %08x", tsn);
1369 dbg_prt_state = 0;
1370 dbg_ack_tsn = tsn;
1371 };
1372
1373 dbg_last_ack_tsn = tsn;
1374 #endif /* SCTP_DEBUG */
1375
1376 } else {
1377 if (tchunk->tsn_gap_acked) {
1378 SCTP_DEBUG_PRINTK("%s: Receiver reneged on "
1379 "data TSN: 0x%x\n",
1380 __FUNCTION__,
1381 tsn);
1382 tchunk->tsn_gap_acked = 0;
1383
1384 bytes_acked -= sctp_data_size(tchunk);
1385
1386 /* RFC 2960 6.3.2 Retransmission Timer Rules
1387 *
1388 * R4) Whenever a SACK is received missing a
1389 * TSN that was previously acknowledged via a
1390 * Gap Ack Block, start T3-rtx for the
1391 * destination address to which the DATA
1392 * chunk was originally
1393 * transmitted if it is not already running.
1394 */
1395 restart_timer = 1;
1396 }
1397
1398 list_add_tail(lchunk, &tlist);
1399
1400 #if SCTP_DEBUG
1401 /* See the above comments on ACK-ed TSNs. */
1402 switch (dbg_prt_state) {
1403 case 1:
1404 if (dbg_last_kept_tsn + 1 == tsn)
1405 break;
1406
1407 if (dbg_last_kept_tsn != dbg_kept_tsn)
1408 SCTP_DEBUG_PRINTK("-%08x",
1409 dbg_last_kept_tsn);
1410
1411 SCTP_DEBUG_PRINTK(",%08x", tsn);
1412 dbg_kept_tsn = tsn;
1413 break;
1414
1415 case 0:
1416 if (dbg_last_ack_tsn != dbg_ack_tsn)
1417 SCTP_DEBUG_PRINTK("-%08x",
1418 dbg_last_ack_tsn);
1419 SCTP_DEBUG_PRINTK("\n");
1420
1421 /* FALL THROUGH... */
1422 default:
1423 SCTP_DEBUG_PRINTK("KEPT: %08x",tsn);
1424 dbg_prt_state = 1;
1425 dbg_kept_tsn = tsn;
1426 };
1427
1428 dbg_last_kept_tsn = tsn;
1429 #endif /* SCTP_DEBUG */
1430 }
1431 }
1432
1433 #if SCTP_DEBUG
1434 /* Finish off the last range, displaying its ending TSN. */
1435 switch (dbg_prt_state) {
1436 case 0:
1437 if (dbg_last_ack_tsn != dbg_ack_tsn) {
1438 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_ack_tsn);
1439 } else {
1440 SCTP_DEBUG_PRINTK("\n");
1441 }
1442 break;
1443
1444 case 1:
1445 if (dbg_last_kept_tsn != dbg_kept_tsn) {
1446 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_kept_tsn);
1447 } else {
1448 SCTP_DEBUG_PRINTK("\n");
1449 }
1450 };
1451 #endif /* SCTP_DEBUG */
1452 if (transport) {
1453 if (bytes_acked) {
1454 /* 8.2. When an outstanding TSN is acknowledged,
1455 * the endpoint shall clear the error counter of
1456 * the destination transport address to which the
1457 * DATA chunk was last sent.
1458 * The association's overall error counter is
1459 * also cleared.
1460 */
1461 transport->error_count = 0;
1462 transport->asoc->overall_error_count = 0;
1463
1464 /* Mark the destination transport address as
1465 * active if it is not so marked.
1466 */
1467 if (!transport->active) {
1468 sctp_assoc_control_transport(
1469 transport->asoc,
1470 transport,
1471 SCTP_TRANSPORT_UP,
1472 SCTP_RECEIVED_SACK);
1473 }
1474
1475 sctp_transport_raise_cwnd(transport, sack_ctsn,
1476 bytes_acked);
1477
1478 transport->flight_size -= bytes_acked;
1479 q->outstanding_bytes -= bytes_acked;
1480 } else {
1481 /* RFC 2960 6.1, sctpimpguide-06 2.15.2
1482 * When a sender is doing zero window probing, it
1483 * should not timeout the association if it continues
1484 * to receive new packets from the receiver. The
1485 * reason is that the receiver MAY keep its window
1486 * closed for an indefinite time.
1487 * A sender is doing zero window probing when the
1488 * receiver's advertised window is zero, and there is
1489 * only one data chunk in flight to the receiver.
1490 */
1491 if (!q->asoc->peer.rwnd &&
1492 !list_empty(&tlist) &&
1493 (sack_ctsn+2 == q->asoc->next_tsn)) {
1494 SCTP_DEBUG_PRINTK("%s: SACK received for zero "
1495 "window probe: %u\n",
1496 __FUNCTION__, sack_ctsn);
1497 q->asoc->overall_error_count = 0;
1498 transport->error_count = 0;
1499 }
1500 }
1501
1502 /* RFC 2960 6.3.2 Retransmission Timer Rules
1503 *
1504 * R2) Whenever all outstanding data sent to an address have
1505 * been acknowledged, turn off the T3-rtx timer of that
1506 * address.
1507 */
1508 if (!transport->flight_size) {
1509 if (timer_pending(&transport->T3_rtx_timer) &&
1510 del_timer(&transport->T3_rtx_timer)) {
1511 sctp_transport_put(transport);
1512 }
1513 } else if (restart_timer) {
1514 if (!mod_timer(&transport->T3_rtx_timer,
1515 jiffies + transport->rto))
1516 sctp_transport_hold(transport);
1517 }
1518 }
1519
1520 list_splice(&tlist, transmitted_queue);
1521 }
1522
1523 /* Mark chunks as missing and consequently may get retransmitted. */
sctp_mark_missing(struct sctp_outq * q,struct list_head * transmitted_queue,struct sctp_transport * transport,__u32 highest_new_tsn_in_sack,int count_of_newacks)1524 static void sctp_mark_missing(struct sctp_outq *q,
1525 struct list_head *transmitted_queue,
1526 struct sctp_transport *transport,
1527 __u32 highest_new_tsn_in_sack,
1528 int count_of_newacks)
1529 {
1530 struct sctp_chunk *chunk;
1531 struct list_head *pos;
1532 __u32 tsn;
1533 char do_fast_retransmit = 0;
1534 struct sctp_transport *primary = q->asoc->peer.primary_path;
1535
1536 list_for_each(pos, transmitted_queue) {
1537
1538 chunk = list_entry(pos, struct sctp_chunk, transmitted_list);
1539 tsn = ntohl(chunk->subh.data_hdr->tsn);
1540
1541 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all
1542 * 'Unacknowledged TSN's', if the TSN number of an
1543 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack'
1544 * value, increment the 'TSN.Missing.Report' count on that
1545 * chunk if it has NOT been fast retransmitted or marked for
1546 * fast retransmit already.
1547 */
1548 if (!chunk->fast_retransmit &&
1549 !chunk->tsn_gap_acked &&
1550 TSN_lt(tsn, highest_new_tsn_in_sack)) {
1551
1552 /* SFR-CACC may require us to skip marking
1553 * this chunk as missing.
1554 */
1555 if (!transport || !sctp_cacc_skip(primary, transport,
1556 count_of_newacks, tsn)) {
1557 chunk->tsn_missing_report++;
1558
1559 SCTP_DEBUG_PRINTK(
1560 "%s: TSN 0x%x missing counter: %d\n",
1561 __FUNCTION__, tsn,
1562 chunk->tsn_missing_report);
1563 }
1564 }
1565 /*
1566 * M4) If any DATA chunk is found to have a
1567 * 'TSN.Missing.Report'
1568 * value larger than or equal to 4, mark that chunk for
1569 * retransmission and start the fast retransmit procedure.
1570 */
1571
1572 if (chunk->tsn_missing_report >= 4) {
1573 chunk->fast_retransmit = 1;
1574 do_fast_retransmit = 1;
1575 }
1576 }
1577
1578 if (transport) {
1579 if (do_fast_retransmit)
1580 sctp_retransmit(q, transport, SCTP_RTXR_FAST_RTX);
1581
1582 SCTP_DEBUG_PRINTK("%s: transport: %p, cwnd: %d, "
1583 "ssthresh: %d, flight_size: %d, pba: %d\n",
1584 __FUNCTION__, transport, transport->cwnd,
1585 transport->ssthresh, transport->flight_size,
1586 transport->partial_bytes_acked);
1587 }
1588 }
1589
1590 /* Is the given TSN acked by this packet? */
sctp_acked(struct sctp_sackhdr * sack,__u32 tsn)1591 static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn)
1592 {
1593 int i;
1594 sctp_sack_variable_t *frags;
1595 __u16 gap;
1596 __u32 ctsn = ntohl(sack->cum_tsn_ack);
1597
1598 if (TSN_lte(tsn, ctsn))
1599 goto pass;
1600
1601 /* 3.3.4 Selective Acknowledgement (SACK) (3):
1602 *
1603 * Gap Ack Blocks:
1604 * These fields contain the Gap Ack Blocks. They are repeated
1605 * for each Gap Ack Block up to the number of Gap Ack Blocks
1606 * defined in the Number of Gap Ack Blocks field. All DATA
1607 * chunks with TSNs greater than or equal to (Cumulative TSN
1608 * Ack + Gap Ack Block Start) and less than or equal to
1609 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack
1610 * Block are assumed to have been received correctly.
1611 */
1612
1613 frags = sack->variable;
1614 gap = tsn - ctsn;
1615 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); ++i) {
1616 if (TSN_lte(ntohs(frags[i].gab.start), gap) &&
1617 TSN_lte(gap, ntohs(frags[i].gab.end)))
1618 goto pass;
1619 }
1620
1621 return 0;
1622 pass:
1623 return 1;
1624 }
1625
sctp_get_skip_pos(struct sctp_fwdtsn_skip * skiplist,int nskips,__u16 stream)1626 static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip *skiplist,
1627 int nskips, __u16 stream)
1628 {
1629 int i;
1630
1631 for (i = 0; i < nskips; i++) {
1632 if (skiplist[i].stream == stream)
1633 return i;
1634 }
1635 return i;
1636 }
1637
1638 /* Create and add a fwdtsn chunk to the outq's control queue if needed. */
sctp_generate_fwdtsn(struct sctp_outq * q,__u32 ctsn)1639 static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 ctsn)
1640 {
1641 struct sctp_association *asoc = q->asoc;
1642 struct sctp_chunk *ftsn_chunk = NULL;
1643 struct sctp_fwdtsn_skip ftsn_skip_arr[10];
1644 int nskips = 0;
1645 int skip_pos = 0;
1646 __u32 tsn;
1647 struct sctp_chunk *chunk;
1648 struct list_head *lchunk, *temp;
1649
1650 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the
1651 * received SACK.
1652 *
1653 * If (Advanced.Peer.Ack.Point < SackCumAck), then update
1654 * Advanced.Peer.Ack.Point to be equal to SackCumAck.
1655 */
1656 if (TSN_lt(asoc->adv_peer_ack_point, ctsn))
1657 asoc->adv_peer_ack_point = ctsn;
1658
1659 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point"
1660 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as
1661 * the chunk next in the out-queue space is marked as "abandoned" as
1662 * shown in the following example:
1663 *
1664 * Assuming that a SACK arrived with the Cumulative TSN ACK 102
1665 * and the Advanced.Peer.Ack.Point is updated to this value:
1666 *
1667 * out-queue at the end of ==> out-queue after Adv.Ack.Point
1668 * normal SACK processing local advancement
1669 * ... ...
1670 * Adv.Ack.Pt-> 102 acked 102 acked
1671 * 103 abandoned 103 abandoned
1672 * 104 abandoned Adv.Ack.P-> 104 abandoned
1673 * 105 105
1674 * 106 acked 106 acked
1675 * ... ...
1676 *
1677 * In this example, the data sender successfully advanced the
1678 * "Advanced.Peer.Ack.Point" from 102 to 104 locally.
1679 */
1680 list_for_each_safe(lchunk, temp, &q->abandoned) {
1681 chunk = list_entry(lchunk, struct sctp_chunk,
1682 transmitted_list);
1683 tsn = ntohl(chunk->subh.data_hdr->tsn);
1684
1685 /* Remove any chunks in the abandoned queue that are acked by
1686 * the ctsn.
1687 */
1688 if (TSN_lte(tsn, ctsn)) {
1689 list_del_init(lchunk);
1690 if (!chunk->tsn_gap_acked) {
1691 chunk->transport->flight_size -=
1692 sctp_data_size(chunk);
1693 q->outstanding_bytes -= sctp_data_size(chunk);
1694 }
1695 sctp_chunk_free(chunk);
1696 } else {
1697 if (TSN_lte(tsn, asoc->adv_peer_ack_point+1)) {
1698 asoc->adv_peer_ack_point = tsn;
1699 if (chunk->chunk_hdr->flags &
1700 SCTP_DATA_UNORDERED)
1701 continue;
1702 skip_pos = sctp_get_skip_pos(&ftsn_skip_arr[0],
1703 nskips,
1704 chunk->subh.data_hdr->stream);
1705 ftsn_skip_arr[skip_pos].stream =
1706 chunk->subh.data_hdr->stream;
1707 ftsn_skip_arr[skip_pos].ssn =
1708 chunk->subh.data_hdr->ssn;
1709 if (skip_pos == nskips)
1710 nskips++;
1711 if (nskips == 10)
1712 break;
1713 } else
1714 break;
1715 }
1716 }
1717
1718 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point"
1719 * is greater than the Cumulative TSN ACK carried in the received
1720 * SACK, the data sender MUST send the data receiver a FORWARD TSN
1721 * chunk containing the latest value of the
1722 * "Advanced.Peer.Ack.Point".
1723 *
1724 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD
1725 * list each stream and sequence number in the forwarded TSN. This
1726 * information will enable the receiver to easily find any
1727 * stranded TSN's waiting on stream reorder queues. Each stream
1728 * SHOULD only be reported once; this means that if multiple
1729 * abandoned messages occur in the same stream then only the
1730 * highest abandoned stream sequence number is reported. If the
1731 * total size of the FORWARD TSN does NOT fit in a single MTU then
1732 * the sender of the FORWARD TSN SHOULD lower the
1733 * Advanced.Peer.Ack.Point to the last TSN that will fit in a
1734 * single MTU.
1735 */
1736 if (asoc->adv_peer_ack_point > ctsn)
1737 ftsn_chunk = sctp_make_fwdtsn(asoc, asoc->adv_peer_ack_point,
1738 nskips, &ftsn_skip_arr[0]);
1739
1740 if (ftsn_chunk) {
1741 __skb_queue_tail(&q->control, (struct sk_buff *)ftsn_chunk);
1742 SCTP_INC_STATS(SctpOutCtrlChunks);
1743 }
1744 }
1745