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