1 /* SCTP kernel implementation 2 * (C) Copyright IBM Corp. 2001, 2004 3 * Copyright (c) 1999-2000 Cisco, Inc. 4 * Copyright (c) 1999-2001 Motorola, Inc. 5 * Copyright (c) 2001-2003 Intel Corp. 6 * 7 * This file is part of the SCTP kernel implementation 8 * 9 * These functions implement the sctp_outq class. The outqueue handles 10 * bundling and queueing of outgoing SCTP chunks. 11 * 12 * This SCTP implementation is free software; 13 * you can redistribute it and/or modify it under the terms of 14 * the GNU General Public License as published by 15 * the Free Software Foundation; either version 2, or (at your option) 16 * any later version. 17 * 18 * This SCTP implementation is distributed in the hope that it 19 * will be useful, but WITHOUT ANY WARRANTY; without even the implied 20 * ************************ 21 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 22 * See the GNU General Public License for more details. 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, see 26 * <http://www.gnu.org/licenses/>. 27 * 28 * Please send any bug reports or fixes you make to the 29 * email address(es): 30 * lksctp developers <linux-sctp@vger.kernel.org> 31 * 32 * Written or modified by: 33 * La Monte H.P. Yarroll <piggy@acm.org> 34 * Karl Knutson <karl@athena.chicago.il.us> 35 * Perry Melange <pmelange@null.cc.uic.edu> 36 * Xingang Guo <xingang.guo@intel.com> 37 * Hui Huang <hui.huang@nokia.com> 38 * Sridhar Samudrala <sri@us.ibm.com> 39 * Jon Grimm <jgrimm@us.ibm.com> 40 */ 41 42 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 43 44 #include <linux/types.h> 45 #include <linux/list.h> /* For struct list_head */ 46 #include <linux/socket.h> 47 #include <linux/ip.h> 48 #include <linux/slab.h> 49 #include <net/sock.h> /* For skb_set_owner_w */ 50 51 #include <net/sctp/sctp.h> 52 #include <net/sctp/sm.h> 53 #include <net/sctp/stream_sched.h> 54 55 /* Declare internal functions here. */ 56 static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn); 57 static void sctp_check_transmitted(struct sctp_outq *q, 58 struct list_head *transmitted_queue, 59 struct sctp_transport *transport, 60 union sctp_addr *saddr, 61 struct sctp_sackhdr *sack, 62 __u32 *highest_new_tsn); 63 64 static void sctp_mark_missing(struct sctp_outq *q, 65 struct list_head *transmitted_queue, 66 struct sctp_transport *transport, 67 __u32 highest_new_tsn, 68 int count_of_newacks); 69 70 static void sctp_outq_flush(struct sctp_outq *q, int rtx_timeout, gfp_t gfp); 71 72 /* Add data to the front of the queue. */ 73 static inline void sctp_outq_head_data(struct sctp_outq *q, 74 struct sctp_chunk *ch) 75 { 76 struct sctp_stream_out_ext *oute; 77 __u16 stream; 78 79 list_add(&ch->list, &q->out_chunk_list); 80 q->out_qlen += ch->skb->len; 81 82 stream = sctp_chunk_stream_no(ch); 83 oute = SCTP_SO(&q->asoc->stream, stream)->ext; 84 list_add(&ch->stream_list, &oute->outq); 85 } 86 87 /* Take data from the front of the queue. */ 88 static inline struct sctp_chunk *sctp_outq_dequeue_data(struct sctp_outq *q) 89 { 90 return q->sched->dequeue(q); 91 } 92 93 /* Add data chunk to the end of the queue. */ 94 static inline void sctp_outq_tail_data(struct sctp_outq *q, 95 struct sctp_chunk *ch) 96 { 97 struct sctp_stream_out_ext *oute; 98 __u16 stream; 99 100 list_add_tail(&ch->list, &q->out_chunk_list); 101 q->out_qlen += ch->skb->len; 102 103 stream = sctp_chunk_stream_no(ch); 104 oute = SCTP_SO(&q->asoc->stream, stream)->ext; 105 list_add_tail(&ch->stream_list, &oute->outq); 106 } 107 108 /* 109 * SFR-CACC algorithm: 110 * D) If count_of_newacks is greater than or equal to 2 111 * and t was not sent to the current primary then the 112 * sender MUST NOT increment missing report count for t. 113 */ 114 static inline int sctp_cacc_skip_3_1_d(struct sctp_transport *primary, 115 struct sctp_transport *transport, 116 int count_of_newacks) 117 { 118 if (count_of_newacks >= 2 && transport != primary) 119 return 1; 120 return 0; 121 } 122 123 /* 124 * SFR-CACC algorithm: 125 * F) If count_of_newacks is less than 2, let d be the 126 * destination to which t was sent. If cacc_saw_newack 127 * is 0 for destination d, then the sender MUST NOT 128 * increment missing report count for t. 129 */ 130 static inline int sctp_cacc_skip_3_1_f(struct sctp_transport *transport, 131 int count_of_newacks) 132 { 133 if (count_of_newacks < 2 && 134 (transport && !transport->cacc.cacc_saw_newack)) 135 return 1; 136 return 0; 137 } 138 139 /* 140 * SFR-CACC algorithm: 141 * 3.1) If CYCLING_CHANGEOVER is 0, the sender SHOULD 142 * execute steps C, D, F. 143 * 144 * C has been implemented in sctp_outq_sack 145 */ 146 static inline int sctp_cacc_skip_3_1(struct sctp_transport *primary, 147 struct sctp_transport *transport, 148 int count_of_newacks) 149 { 150 if (!primary->cacc.cycling_changeover) { 151 if (sctp_cacc_skip_3_1_d(primary, transport, count_of_newacks)) 152 return 1; 153 if (sctp_cacc_skip_3_1_f(transport, count_of_newacks)) 154 return 1; 155 return 0; 156 } 157 return 0; 158 } 159 160 /* 161 * SFR-CACC algorithm: 162 * 3.2) Else if CYCLING_CHANGEOVER is 1, and t is less 163 * than next_tsn_at_change of the current primary, then 164 * the sender MUST NOT increment missing report count 165 * for t. 166 */ 167 static inline int sctp_cacc_skip_3_2(struct sctp_transport *primary, __u32 tsn) 168 { 169 if (primary->cacc.cycling_changeover && 170 TSN_lt(tsn, primary->cacc.next_tsn_at_change)) 171 return 1; 172 return 0; 173 } 174 175 /* 176 * SFR-CACC algorithm: 177 * 3) If the missing report count for TSN t is to be 178 * incremented according to [RFC2960] and 179 * [SCTP_STEWART-2002], and CHANGEOVER_ACTIVE is set, 180 * then the sender MUST further execute steps 3.1 and 181 * 3.2 to determine if the missing report count for 182 * TSN t SHOULD NOT be incremented. 183 * 184 * 3.3) If 3.1 and 3.2 do not dictate that the missing 185 * report count for t should not be incremented, then 186 * the sender SHOULD increment missing report count for 187 * t (according to [RFC2960] and [SCTP_STEWART_2002]). 188 */ 189 static inline int sctp_cacc_skip(struct sctp_transport *primary, 190 struct sctp_transport *transport, 191 int count_of_newacks, 192 __u32 tsn) 193 { 194 if (primary->cacc.changeover_active && 195 (sctp_cacc_skip_3_1(primary, transport, count_of_newacks) || 196 sctp_cacc_skip_3_2(primary, tsn))) 197 return 1; 198 return 0; 199 } 200 201 /* Initialize an existing sctp_outq. This does the boring stuff. 202 * You still need to define handlers if you really want to DO 203 * something with this structure... 204 */ 205 void sctp_outq_init(struct sctp_association *asoc, struct sctp_outq *q) 206 { 207 memset(q, 0, sizeof(struct sctp_outq)); 208 209 q->asoc = asoc; 210 INIT_LIST_HEAD(&q->out_chunk_list); 211 INIT_LIST_HEAD(&q->control_chunk_list); 212 INIT_LIST_HEAD(&q->retransmit); 213 INIT_LIST_HEAD(&q->sacked); 214 INIT_LIST_HEAD(&q->abandoned); 215 sctp_sched_set_sched(asoc, SCTP_SS_FCFS); 216 } 217 218 /* Free the outqueue structure and any related pending chunks. 219 */ 220 static void __sctp_outq_teardown(struct sctp_outq *q) 221 { 222 struct sctp_transport *transport; 223 struct list_head *lchunk, *temp; 224 struct sctp_chunk *chunk, *tmp; 225 226 /* Throw away unacknowledged chunks. */ 227 list_for_each_entry(transport, &q->asoc->peer.transport_addr_list, 228 transports) { 229 while ((lchunk = sctp_list_dequeue(&transport->transmitted)) != NULL) { 230 chunk = list_entry(lchunk, struct sctp_chunk, 231 transmitted_list); 232 /* Mark as part of a failed message. */ 233 sctp_chunk_fail(chunk, q->error); 234 sctp_chunk_free(chunk); 235 } 236 } 237 238 /* Throw away chunks that have been gap ACKed. */ 239 list_for_each_safe(lchunk, temp, &q->sacked) { 240 list_del_init(lchunk); 241 chunk = list_entry(lchunk, struct sctp_chunk, 242 transmitted_list); 243 sctp_chunk_fail(chunk, q->error); 244 sctp_chunk_free(chunk); 245 } 246 247 /* Throw away any chunks in the retransmit queue. */ 248 list_for_each_safe(lchunk, temp, &q->retransmit) { 249 list_del_init(lchunk); 250 chunk = list_entry(lchunk, struct sctp_chunk, 251 transmitted_list); 252 sctp_chunk_fail(chunk, q->error); 253 sctp_chunk_free(chunk); 254 } 255 256 /* Throw away any chunks that are in the abandoned queue. */ 257 list_for_each_safe(lchunk, temp, &q->abandoned) { 258 list_del_init(lchunk); 259 chunk = list_entry(lchunk, struct sctp_chunk, 260 transmitted_list); 261 sctp_chunk_fail(chunk, q->error); 262 sctp_chunk_free(chunk); 263 } 264 265 /* Throw away any leftover data chunks. */ 266 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) { 267 sctp_sched_dequeue_done(q, chunk); 268 269 /* Mark as send failure. */ 270 sctp_chunk_fail(chunk, q->error); 271 sctp_chunk_free(chunk); 272 } 273 274 /* Throw away any leftover control chunks. */ 275 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) { 276 list_del_init(&chunk->list); 277 sctp_chunk_free(chunk); 278 } 279 } 280 281 void sctp_outq_teardown(struct sctp_outq *q) 282 { 283 __sctp_outq_teardown(q); 284 sctp_outq_init(q->asoc, q); 285 } 286 287 /* Free the outqueue structure and any related pending chunks. */ 288 void sctp_outq_free(struct sctp_outq *q) 289 { 290 /* Throw away leftover chunks. */ 291 __sctp_outq_teardown(q); 292 } 293 294 /* Put a new chunk in an sctp_outq. */ 295 void sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk, gfp_t gfp) 296 { 297 struct net *net = sock_net(q->asoc->base.sk); 298 299 pr_debug("%s: outq:%p, chunk:%p[%s]\n", __func__, q, chunk, 300 chunk && chunk->chunk_hdr ? 301 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) : 302 "illegal chunk"); 303 304 /* If it is data, queue it up, otherwise, send it 305 * immediately. 306 */ 307 if (sctp_chunk_is_data(chunk)) { 308 pr_debug("%s: outqueueing: outq:%p, chunk:%p[%s])\n", 309 __func__, q, chunk, chunk && chunk->chunk_hdr ? 310 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) : 311 "illegal chunk"); 312 313 sctp_outq_tail_data(q, chunk); 314 if (chunk->asoc->peer.prsctp_capable && 315 SCTP_PR_PRIO_ENABLED(chunk->sinfo.sinfo_flags)) 316 chunk->asoc->sent_cnt_removable++; 317 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) 318 SCTP_INC_STATS(net, SCTP_MIB_OUTUNORDERCHUNKS); 319 else 320 SCTP_INC_STATS(net, SCTP_MIB_OUTORDERCHUNKS); 321 } else { 322 list_add_tail(&chunk->list, &q->control_chunk_list); 323 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 324 } 325 326 if (!q->cork) 327 sctp_outq_flush(q, 0, gfp); 328 } 329 330 /* Insert a chunk into the sorted list based on the TSNs. The retransmit list 331 * and the abandoned list are in ascending order. 332 */ 333 static void sctp_insert_list(struct list_head *head, struct list_head *new) 334 { 335 struct list_head *pos; 336 struct sctp_chunk *nchunk, *lchunk; 337 __u32 ntsn, ltsn; 338 int done = 0; 339 340 nchunk = list_entry(new, struct sctp_chunk, transmitted_list); 341 ntsn = ntohl(nchunk->subh.data_hdr->tsn); 342 343 list_for_each(pos, head) { 344 lchunk = list_entry(pos, struct sctp_chunk, transmitted_list); 345 ltsn = ntohl(lchunk->subh.data_hdr->tsn); 346 if (TSN_lt(ntsn, ltsn)) { 347 list_add(new, pos->prev); 348 done = 1; 349 break; 350 } 351 } 352 if (!done) 353 list_add_tail(new, head); 354 } 355 356 static int sctp_prsctp_prune_sent(struct sctp_association *asoc, 357 struct sctp_sndrcvinfo *sinfo, 358 struct list_head *queue, int msg_len) 359 { 360 struct sctp_chunk *chk, *temp; 361 362 list_for_each_entry_safe(chk, temp, queue, transmitted_list) { 363 struct sctp_stream_out *streamout; 364 365 if (!chk->msg->abandoned && 366 (!SCTP_PR_PRIO_ENABLED(chk->sinfo.sinfo_flags) || 367 chk->sinfo.sinfo_timetolive <= sinfo->sinfo_timetolive)) 368 continue; 369 370 chk->msg->abandoned = 1; 371 list_del_init(&chk->transmitted_list); 372 sctp_insert_list(&asoc->outqueue.abandoned, 373 &chk->transmitted_list); 374 375 streamout = SCTP_SO(&asoc->stream, chk->sinfo.sinfo_stream); 376 asoc->sent_cnt_removable--; 377 asoc->abandoned_sent[SCTP_PR_INDEX(PRIO)]++; 378 streamout->ext->abandoned_sent[SCTP_PR_INDEX(PRIO)]++; 379 380 if (queue != &asoc->outqueue.retransmit && 381 !chk->tsn_gap_acked) { 382 if (chk->transport) 383 chk->transport->flight_size -= 384 sctp_data_size(chk); 385 asoc->outqueue.outstanding_bytes -= sctp_data_size(chk); 386 } 387 388 msg_len -= SCTP_DATA_SNDSIZE(chk) + 389 sizeof(struct sk_buff) + 390 sizeof(struct sctp_chunk); 391 if (msg_len <= 0) 392 break; 393 } 394 395 return msg_len; 396 } 397 398 static int sctp_prsctp_prune_unsent(struct sctp_association *asoc, 399 struct sctp_sndrcvinfo *sinfo, int msg_len) 400 { 401 struct sctp_outq *q = &asoc->outqueue; 402 struct sctp_chunk *chk, *temp; 403 404 q->sched->unsched_all(&asoc->stream); 405 406 list_for_each_entry_safe(chk, temp, &q->out_chunk_list, list) { 407 if (!chk->msg->abandoned && 408 (!(chk->chunk_hdr->flags & SCTP_DATA_FIRST_FRAG) || 409 !SCTP_PR_PRIO_ENABLED(chk->sinfo.sinfo_flags) || 410 chk->sinfo.sinfo_timetolive <= sinfo->sinfo_timetolive)) 411 continue; 412 413 chk->msg->abandoned = 1; 414 sctp_sched_dequeue_common(q, chk); 415 asoc->sent_cnt_removable--; 416 asoc->abandoned_unsent[SCTP_PR_INDEX(PRIO)]++; 417 if (chk->sinfo.sinfo_stream < asoc->stream.outcnt) { 418 struct sctp_stream_out *streamout = 419 SCTP_SO(&asoc->stream, chk->sinfo.sinfo_stream); 420 421 streamout->ext->abandoned_unsent[SCTP_PR_INDEX(PRIO)]++; 422 } 423 424 msg_len -= SCTP_DATA_SNDSIZE(chk) + 425 sizeof(struct sk_buff) + 426 sizeof(struct sctp_chunk); 427 sctp_chunk_free(chk); 428 if (msg_len <= 0) 429 break; 430 } 431 432 q->sched->sched_all(&asoc->stream); 433 434 return msg_len; 435 } 436 437 /* Abandon the chunks according their priorities */ 438 void sctp_prsctp_prune(struct sctp_association *asoc, 439 struct sctp_sndrcvinfo *sinfo, int msg_len) 440 { 441 struct sctp_transport *transport; 442 443 if (!asoc->peer.prsctp_capable || !asoc->sent_cnt_removable) 444 return; 445 446 msg_len = sctp_prsctp_prune_sent(asoc, sinfo, 447 &asoc->outqueue.retransmit, 448 msg_len); 449 if (msg_len <= 0) 450 return; 451 452 list_for_each_entry(transport, &asoc->peer.transport_addr_list, 453 transports) { 454 msg_len = sctp_prsctp_prune_sent(asoc, sinfo, 455 &transport->transmitted, 456 msg_len); 457 if (msg_len <= 0) 458 return; 459 } 460 461 sctp_prsctp_prune_unsent(asoc, sinfo, msg_len); 462 } 463 464 /* Mark all the eligible packets on a transport for retransmission. */ 465 void sctp_retransmit_mark(struct sctp_outq *q, 466 struct sctp_transport *transport, 467 __u8 reason) 468 { 469 struct list_head *lchunk, *ltemp; 470 struct sctp_chunk *chunk; 471 472 /* Walk through the specified transmitted queue. */ 473 list_for_each_safe(lchunk, ltemp, &transport->transmitted) { 474 chunk = list_entry(lchunk, struct sctp_chunk, 475 transmitted_list); 476 477 /* If the chunk is abandoned, move it to abandoned list. */ 478 if (sctp_chunk_abandoned(chunk)) { 479 list_del_init(lchunk); 480 sctp_insert_list(&q->abandoned, lchunk); 481 482 /* If this chunk has not been previousely acked, 483 * stop considering it 'outstanding'. Our peer 484 * will most likely never see it since it will 485 * not be retransmitted 486 */ 487 if (!chunk->tsn_gap_acked) { 488 if (chunk->transport) 489 chunk->transport->flight_size -= 490 sctp_data_size(chunk); 491 q->outstanding_bytes -= sctp_data_size(chunk); 492 q->asoc->peer.rwnd += sctp_data_size(chunk); 493 } 494 continue; 495 } 496 497 /* If we are doing retransmission due to a timeout or pmtu 498 * discovery, only the chunks that are not yet acked should 499 * be added to the retransmit queue. 500 */ 501 if ((reason == SCTP_RTXR_FAST_RTX && 502 (chunk->fast_retransmit == SCTP_NEED_FRTX)) || 503 (reason != SCTP_RTXR_FAST_RTX && !chunk->tsn_gap_acked)) { 504 /* RFC 2960 6.2.1 Processing a Received SACK 505 * 506 * C) Any time a DATA chunk is marked for 507 * retransmission (via either T3-rtx timer expiration 508 * (Section 6.3.3) or via fast retransmit 509 * (Section 7.2.4)), add the data size of those 510 * chunks to the rwnd. 511 */ 512 q->asoc->peer.rwnd += sctp_data_size(chunk); 513 q->outstanding_bytes -= sctp_data_size(chunk); 514 if (chunk->transport) 515 transport->flight_size -= sctp_data_size(chunk); 516 517 /* sctpimpguide-05 Section 2.8.2 518 * M5) If a T3-rtx timer expires, the 519 * 'TSN.Missing.Report' of all affected TSNs is set 520 * to 0. 521 */ 522 chunk->tsn_missing_report = 0; 523 524 /* If a chunk that is being used for RTT measurement 525 * has to be retransmitted, we cannot use this chunk 526 * anymore for RTT measurements. Reset rto_pending so 527 * that a new RTT measurement is started when a new 528 * data chunk is sent. 529 */ 530 if (chunk->rtt_in_progress) { 531 chunk->rtt_in_progress = 0; 532 transport->rto_pending = 0; 533 } 534 535 /* Move the chunk to the retransmit queue. The chunks 536 * on the retransmit queue are always kept in order. 537 */ 538 list_del_init(lchunk); 539 sctp_insert_list(&q->retransmit, lchunk); 540 } 541 } 542 543 pr_debug("%s: transport:%p, reason:%d, cwnd:%d, ssthresh:%d, " 544 "flight_size:%d, pba:%d\n", __func__, transport, reason, 545 transport->cwnd, transport->ssthresh, transport->flight_size, 546 transport->partial_bytes_acked); 547 } 548 549 /* Mark all the eligible packets on a transport for retransmission and force 550 * one packet out. 551 */ 552 void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport, 553 enum sctp_retransmit_reason reason) 554 { 555 struct net *net = sock_net(q->asoc->base.sk); 556 557 switch (reason) { 558 case SCTP_RTXR_T3_RTX: 559 SCTP_INC_STATS(net, SCTP_MIB_T3_RETRANSMITS); 560 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_T3_RTX); 561 /* Update the retran path if the T3-rtx timer has expired for 562 * the current retran path. 563 */ 564 if (transport == transport->asoc->peer.retran_path) 565 sctp_assoc_update_retran_path(transport->asoc); 566 transport->asoc->rtx_data_chunks += 567 transport->asoc->unack_data; 568 break; 569 case SCTP_RTXR_FAST_RTX: 570 SCTP_INC_STATS(net, SCTP_MIB_FAST_RETRANSMITS); 571 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_FAST_RTX); 572 q->fast_rtx = 1; 573 break; 574 case SCTP_RTXR_PMTUD: 575 SCTP_INC_STATS(net, SCTP_MIB_PMTUD_RETRANSMITS); 576 break; 577 case SCTP_RTXR_T1_RTX: 578 SCTP_INC_STATS(net, SCTP_MIB_T1_RETRANSMITS); 579 transport->asoc->init_retries++; 580 break; 581 default: 582 BUG(); 583 } 584 585 sctp_retransmit_mark(q, transport, reason); 586 587 /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination, 588 * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by 589 * following the procedures outlined in C1 - C5. 590 */ 591 if (reason == SCTP_RTXR_T3_RTX) 592 q->asoc->stream.si->generate_ftsn(q, q->asoc->ctsn_ack_point); 593 594 /* Flush the queues only on timeout, since fast_rtx is only 595 * triggered during sack processing and the queue 596 * will be flushed at the end. 597 */ 598 if (reason != SCTP_RTXR_FAST_RTX) 599 sctp_outq_flush(q, /* rtx_timeout */ 1, GFP_ATOMIC); 600 } 601 602 /* 603 * Transmit DATA chunks on the retransmit queue. Upon return from 604 * __sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which 605 * need to be transmitted by the caller. 606 * We assume that pkt->transport has already been set. 607 * 608 * The return value is a normal kernel error return value. 609 */ 610 static int __sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt, 611 int rtx_timeout, int *start_timer, gfp_t gfp) 612 { 613 struct sctp_transport *transport = pkt->transport; 614 struct sctp_chunk *chunk, *chunk1; 615 struct list_head *lqueue; 616 enum sctp_xmit status; 617 int error = 0; 618 int timer = 0; 619 int done = 0; 620 int fast_rtx; 621 622 lqueue = &q->retransmit; 623 fast_rtx = q->fast_rtx; 624 625 /* This loop handles time-out retransmissions, fast retransmissions, 626 * and retransmissions due to opening of whindow. 627 * 628 * RFC 2960 6.3.3 Handle T3-rtx Expiration 629 * 630 * E3) Determine how many of the earliest (i.e., lowest TSN) 631 * outstanding DATA chunks for the address for which the 632 * T3-rtx has expired will fit into a single packet, subject 633 * to the MTU constraint for the path corresponding to the 634 * destination transport address to which the retransmission 635 * is being sent (this may be different from the address for 636 * which the timer expires [see Section 6.4]). Call this value 637 * K. Bundle and retransmit those K DATA chunks in a single 638 * packet to the destination endpoint. 639 * 640 * [Just to be painfully clear, if we are retransmitting 641 * because a timeout just happened, we should send only ONE 642 * packet of retransmitted data.] 643 * 644 * For fast retransmissions we also send only ONE packet. However, 645 * if we are just flushing the queue due to open window, we'll 646 * try to send as much as possible. 647 */ 648 list_for_each_entry_safe(chunk, chunk1, lqueue, transmitted_list) { 649 /* If the chunk is abandoned, move it to abandoned list. */ 650 if (sctp_chunk_abandoned(chunk)) { 651 list_del_init(&chunk->transmitted_list); 652 sctp_insert_list(&q->abandoned, 653 &chunk->transmitted_list); 654 continue; 655 } 656 657 /* Make sure that Gap Acked TSNs are not retransmitted. A 658 * simple approach is just to move such TSNs out of the 659 * way and into a 'transmitted' queue and skip to the 660 * next chunk. 661 */ 662 if (chunk->tsn_gap_acked) { 663 list_move_tail(&chunk->transmitted_list, 664 &transport->transmitted); 665 continue; 666 } 667 668 /* If we are doing fast retransmit, ignore non-fast_rtransmit 669 * chunks 670 */ 671 if (fast_rtx && !chunk->fast_retransmit) 672 continue; 673 674 redo: 675 /* Attempt to append this chunk to the packet. */ 676 status = sctp_packet_append_chunk(pkt, chunk); 677 678 switch (status) { 679 case SCTP_XMIT_PMTU_FULL: 680 if (!pkt->has_data && !pkt->has_cookie_echo) { 681 /* If this packet did not contain DATA then 682 * retransmission did not happen, so do it 683 * again. We'll ignore the error here since 684 * control chunks are already freed so there 685 * is nothing we can do. 686 */ 687 sctp_packet_transmit(pkt, gfp); 688 goto redo; 689 } 690 691 /* Send this packet. */ 692 error = sctp_packet_transmit(pkt, gfp); 693 694 /* If we are retransmitting, we should only 695 * send a single packet. 696 * Otherwise, try appending this chunk again. 697 */ 698 if (rtx_timeout || fast_rtx) 699 done = 1; 700 else 701 goto redo; 702 703 /* Bundle next chunk in the next round. */ 704 break; 705 706 case SCTP_XMIT_RWND_FULL: 707 /* Send this packet. */ 708 error = sctp_packet_transmit(pkt, gfp); 709 710 /* Stop sending DATA as there is no more room 711 * at the receiver. 712 */ 713 done = 1; 714 break; 715 716 case SCTP_XMIT_DELAY: 717 /* Send this packet. */ 718 error = sctp_packet_transmit(pkt, gfp); 719 720 /* Stop sending DATA because of nagle delay. */ 721 done = 1; 722 break; 723 724 default: 725 /* The append was successful, so add this chunk to 726 * the transmitted list. 727 */ 728 list_move_tail(&chunk->transmitted_list, 729 &transport->transmitted); 730 731 /* Mark the chunk as ineligible for fast retransmit 732 * after it is retransmitted. 733 */ 734 if (chunk->fast_retransmit == SCTP_NEED_FRTX) 735 chunk->fast_retransmit = SCTP_DONT_FRTX; 736 737 q->asoc->stats.rtxchunks++; 738 break; 739 } 740 741 /* Set the timer if there were no errors */ 742 if (!error && !timer) 743 timer = 1; 744 745 if (done) 746 break; 747 } 748 749 /* If we are here due to a retransmit timeout or a fast 750 * retransmit and if there are any chunks left in the retransmit 751 * queue that could not fit in the PMTU sized packet, they need 752 * to be marked as ineligible for a subsequent fast retransmit. 753 */ 754 if (rtx_timeout || fast_rtx) { 755 list_for_each_entry(chunk1, lqueue, transmitted_list) { 756 if (chunk1->fast_retransmit == SCTP_NEED_FRTX) 757 chunk1->fast_retransmit = SCTP_DONT_FRTX; 758 } 759 } 760 761 *start_timer = timer; 762 763 /* Clear fast retransmit hint */ 764 if (fast_rtx) 765 q->fast_rtx = 0; 766 767 return error; 768 } 769 770 /* Cork the outqueue so queued chunks are really queued. */ 771 void sctp_outq_uncork(struct sctp_outq *q, gfp_t gfp) 772 { 773 if (q->cork) 774 q->cork = 0; 775 776 sctp_outq_flush(q, 0, gfp); 777 } 778 779 static int sctp_packet_singleton(struct sctp_transport *transport, 780 struct sctp_chunk *chunk, gfp_t gfp) 781 { 782 const struct sctp_association *asoc = transport->asoc; 783 const __u16 sport = asoc->base.bind_addr.port; 784 const __u16 dport = asoc->peer.port; 785 const __u32 vtag = asoc->peer.i.init_tag; 786 struct sctp_packet singleton; 787 788 sctp_packet_init(&singleton, transport, sport, dport); 789 sctp_packet_config(&singleton, vtag, 0); 790 sctp_packet_append_chunk(&singleton, chunk); 791 return sctp_packet_transmit(&singleton, gfp); 792 } 793 794 /* Struct to hold the context during sctp outq flush */ 795 struct sctp_flush_ctx { 796 struct sctp_outq *q; 797 /* Current transport being used. It's NOT the same as curr active one */ 798 struct sctp_transport *transport; 799 /* These transports have chunks to send. */ 800 struct list_head transport_list; 801 struct sctp_association *asoc; 802 /* Packet on the current transport above */ 803 struct sctp_packet *packet; 804 gfp_t gfp; 805 }; 806 807 /* transport: current transport */ 808 static void sctp_outq_select_transport(struct sctp_flush_ctx *ctx, 809 struct sctp_chunk *chunk) 810 { 811 struct sctp_transport *new_transport = chunk->transport; 812 813 if (!new_transport) { 814 if (!sctp_chunk_is_data(chunk)) { 815 /* If we have a prior transport pointer, see if 816 * the destination address of the chunk 817 * matches the destination address of the 818 * current transport. If not a match, then 819 * try to look up the transport with a given 820 * destination address. We do this because 821 * after processing ASCONFs, we may have new 822 * transports created. 823 */ 824 if (ctx->transport && sctp_cmp_addr_exact(&chunk->dest, 825 &ctx->transport->ipaddr)) 826 new_transport = ctx->transport; 827 else 828 new_transport = sctp_assoc_lookup_paddr(ctx->asoc, 829 &chunk->dest); 830 } 831 832 /* if we still don't have a new transport, then 833 * use the current active path. 834 */ 835 if (!new_transport) 836 new_transport = ctx->asoc->peer.active_path; 837 } else { 838 __u8 type; 839 840 switch (new_transport->state) { 841 case SCTP_INACTIVE: 842 case SCTP_UNCONFIRMED: 843 case SCTP_PF: 844 /* If the chunk is Heartbeat or Heartbeat Ack, 845 * send it to chunk->transport, even if it's 846 * inactive. 847 * 848 * 3.3.6 Heartbeat Acknowledgement: 849 * ... 850 * A HEARTBEAT ACK is always sent to the source IP 851 * address of the IP datagram containing the 852 * HEARTBEAT chunk to which this ack is responding. 853 * ... 854 * 855 * ASCONF_ACKs also must be sent to the source. 856 */ 857 type = chunk->chunk_hdr->type; 858 if (type != SCTP_CID_HEARTBEAT && 859 type != SCTP_CID_HEARTBEAT_ACK && 860 type != SCTP_CID_ASCONF_ACK) 861 new_transport = ctx->asoc->peer.active_path; 862 break; 863 default: 864 break; 865 } 866 } 867 868 /* Are we switching transports? Take care of transport locks. */ 869 if (new_transport != ctx->transport) { 870 ctx->transport = new_transport; 871 ctx->packet = &ctx->transport->packet; 872 873 if (list_empty(&ctx->transport->send_ready)) 874 list_add_tail(&ctx->transport->send_ready, 875 &ctx->transport_list); 876 877 sctp_packet_config(ctx->packet, 878 ctx->asoc->peer.i.init_tag, 879 ctx->asoc->peer.ecn_capable); 880 /* We've switched transports, so apply the 881 * Burst limit to the new transport. 882 */ 883 sctp_transport_burst_limited(ctx->transport); 884 } 885 } 886 887 static void sctp_outq_flush_ctrl(struct sctp_flush_ctx *ctx) 888 { 889 struct sctp_chunk *chunk, *tmp; 890 enum sctp_xmit status; 891 int one_packet, error; 892 893 list_for_each_entry_safe(chunk, tmp, &ctx->q->control_chunk_list, list) { 894 one_packet = 0; 895 896 /* RFC 5061, 5.3 897 * F1) This means that until such time as the ASCONF 898 * containing the add is acknowledged, the sender MUST 899 * NOT use the new IP address as a source for ANY SCTP 900 * packet except on carrying an ASCONF Chunk. 901 */ 902 if (ctx->asoc->src_out_of_asoc_ok && 903 chunk->chunk_hdr->type != SCTP_CID_ASCONF) 904 continue; 905 906 list_del_init(&chunk->list); 907 908 /* Pick the right transport to use. Should always be true for 909 * the first chunk as we don't have a transport by then. 910 */ 911 sctp_outq_select_transport(ctx, chunk); 912 913 switch (chunk->chunk_hdr->type) { 914 /* 6.10 Bundling 915 * ... 916 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN 917 * COMPLETE with any other chunks. [Send them immediately.] 918 */ 919 case SCTP_CID_INIT: 920 case SCTP_CID_INIT_ACK: 921 case SCTP_CID_SHUTDOWN_COMPLETE: 922 error = sctp_packet_singleton(ctx->transport, chunk, 923 ctx->gfp); 924 if (error < 0) { 925 ctx->asoc->base.sk->sk_err = -error; 926 return; 927 } 928 break; 929 930 case SCTP_CID_ABORT: 931 if (sctp_test_T_bit(chunk)) 932 ctx->packet->vtag = ctx->asoc->c.my_vtag; 933 /* fallthru */ 934 935 /* The following chunks are "response" chunks, i.e. 936 * they are generated in response to something we 937 * received. If we are sending these, then we can 938 * send only 1 packet containing these chunks. 939 */ 940 case SCTP_CID_HEARTBEAT_ACK: 941 case SCTP_CID_SHUTDOWN_ACK: 942 case SCTP_CID_COOKIE_ACK: 943 case SCTP_CID_COOKIE_ECHO: 944 case SCTP_CID_ERROR: 945 case SCTP_CID_ECN_CWR: 946 case SCTP_CID_ASCONF_ACK: 947 one_packet = 1; 948 /* Fall through */ 949 950 case SCTP_CID_SACK: 951 case SCTP_CID_HEARTBEAT: 952 case SCTP_CID_SHUTDOWN: 953 case SCTP_CID_ECN_ECNE: 954 case SCTP_CID_ASCONF: 955 case SCTP_CID_FWD_TSN: 956 case SCTP_CID_I_FWD_TSN: 957 case SCTP_CID_RECONF: 958 status = sctp_packet_transmit_chunk(ctx->packet, chunk, 959 one_packet, ctx->gfp); 960 if (status != SCTP_XMIT_OK) { 961 /* put the chunk back */ 962 list_add(&chunk->list, &ctx->q->control_chunk_list); 963 break; 964 } 965 966 ctx->asoc->stats.octrlchunks++; 967 /* PR-SCTP C5) If a FORWARD TSN is sent, the 968 * sender MUST assure that at least one T3-rtx 969 * timer is running. 970 */ 971 if (chunk->chunk_hdr->type == SCTP_CID_FWD_TSN || 972 chunk->chunk_hdr->type == SCTP_CID_I_FWD_TSN) { 973 sctp_transport_reset_t3_rtx(ctx->transport); 974 ctx->transport->last_time_sent = jiffies; 975 } 976 977 if (chunk == ctx->asoc->strreset_chunk) 978 sctp_transport_reset_reconf_timer(ctx->transport); 979 980 break; 981 982 default: 983 /* We built a chunk with an illegal type! */ 984 BUG(); 985 } 986 } 987 } 988 989 /* Returns false if new data shouldn't be sent */ 990 static bool sctp_outq_flush_rtx(struct sctp_flush_ctx *ctx, 991 int rtx_timeout) 992 { 993 int error, start_timer = 0; 994 995 if (ctx->asoc->peer.retran_path->state == SCTP_UNCONFIRMED) 996 return false; 997 998 if (ctx->transport != ctx->asoc->peer.retran_path) { 999 /* Switch transports & prepare the packet. */ 1000 ctx->transport = ctx->asoc->peer.retran_path; 1001 ctx->packet = &ctx->transport->packet; 1002 1003 if (list_empty(&ctx->transport->send_ready)) 1004 list_add_tail(&ctx->transport->send_ready, 1005 &ctx->transport_list); 1006 1007 sctp_packet_config(ctx->packet, ctx->asoc->peer.i.init_tag, 1008 ctx->asoc->peer.ecn_capable); 1009 } 1010 1011 error = __sctp_outq_flush_rtx(ctx->q, ctx->packet, rtx_timeout, 1012 &start_timer, ctx->gfp); 1013 if (error < 0) 1014 ctx->asoc->base.sk->sk_err = -error; 1015 1016 if (start_timer) { 1017 sctp_transport_reset_t3_rtx(ctx->transport); 1018 ctx->transport->last_time_sent = jiffies; 1019 } 1020 1021 /* This can happen on COOKIE-ECHO resend. Only 1022 * one chunk can get bundled with a COOKIE-ECHO. 1023 */ 1024 if (ctx->packet->has_cookie_echo) 1025 return false; 1026 1027 /* Don't send new data if there is still data 1028 * waiting to retransmit. 1029 */ 1030 if (!list_empty(&ctx->q->retransmit)) 1031 return false; 1032 1033 return true; 1034 } 1035 1036 static void sctp_outq_flush_data(struct sctp_flush_ctx *ctx, 1037 int rtx_timeout) 1038 { 1039 struct sctp_chunk *chunk; 1040 enum sctp_xmit status; 1041 1042 /* Is it OK to send data chunks? */ 1043 switch (ctx->asoc->state) { 1044 case SCTP_STATE_COOKIE_ECHOED: 1045 /* Only allow bundling when this packet has a COOKIE-ECHO 1046 * chunk. 1047 */ 1048 if (!ctx->packet || !ctx->packet->has_cookie_echo) 1049 return; 1050 1051 /* fallthru */ 1052 case SCTP_STATE_ESTABLISHED: 1053 case SCTP_STATE_SHUTDOWN_PENDING: 1054 case SCTP_STATE_SHUTDOWN_RECEIVED: 1055 break; 1056 1057 default: 1058 /* Do nothing. */ 1059 return; 1060 } 1061 1062 /* RFC 2960 6.1 Transmission of DATA Chunks 1063 * 1064 * C) When the time comes for the sender to transmit, 1065 * before sending new DATA chunks, the sender MUST 1066 * first transmit any outstanding DATA chunks which 1067 * are marked for retransmission (limited by the 1068 * current cwnd). 1069 */ 1070 if (!list_empty(&ctx->q->retransmit) && 1071 !sctp_outq_flush_rtx(ctx, rtx_timeout)) 1072 return; 1073 1074 /* Apply Max.Burst limitation to the current transport in 1075 * case it will be used for new data. We are going to 1076 * rest it before we return, but we want to apply the limit 1077 * to the currently queued data. 1078 */ 1079 if (ctx->transport) 1080 sctp_transport_burst_limited(ctx->transport); 1081 1082 /* Finally, transmit new packets. */ 1083 while ((chunk = sctp_outq_dequeue_data(ctx->q)) != NULL) { 1084 __u32 sid = ntohs(chunk->subh.data_hdr->stream); 1085 __u8 stream_state = SCTP_SO(&ctx->asoc->stream, sid)->state; 1086 1087 /* Has this chunk expired? */ 1088 if (sctp_chunk_abandoned(chunk)) { 1089 sctp_sched_dequeue_done(ctx->q, chunk); 1090 sctp_chunk_fail(chunk, 0); 1091 sctp_chunk_free(chunk); 1092 continue; 1093 } 1094 1095 if (stream_state == SCTP_STREAM_CLOSED) { 1096 sctp_outq_head_data(ctx->q, chunk); 1097 break; 1098 } 1099 1100 sctp_outq_select_transport(ctx, chunk); 1101 1102 pr_debug("%s: outq:%p, chunk:%p[%s], tx-tsn:0x%x skb->head:%p skb->users:%d\n", 1103 __func__, ctx->q, chunk, chunk && chunk->chunk_hdr ? 1104 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) : 1105 "illegal chunk", ntohl(chunk->subh.data_hdr->tsn), 1106 chunk->skb ? chunk->skb->head : NULL, chunk->skb ? 1107 refcount_read(&chunk->skb->users) : -1); 1108 1109 /* Add the chunk to the packet. */ 1110 status = sctp_packet_transmit_chunk(ctx->packet, chunk, 0, 1111 ctx->gfp); 1112 if (status != SCTP_XMIT_OK) { 1113 /* We could not append this chunk, so put 1114 * the chunk back on the output queue. 1115 */ 1116 pr_debug("%s: could not transmit tsn:0x%x, status:%d\n", 1117 __func__, ntohl(chunk->subh.data_hdr->tsn), 1118 status); 1119 1120 sctp_outq_head_data(ctx->q, chunk); 1121 break; 1122 } 1123 1124 /* The sender is in the SHUTDOWN-PENDING state, 1125 * The sender MAY set the I-bit in the DATA 1126 * chunk header. 1127 */ 1128 if (ctx->asoc->state == SCTP_STATE_SHUTDOWN_PENDING) 1129 chunk->chunk_hdr->flags |= SCTP_DATA_SACK_IMM; 1130 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) 1131 ctx->asoc->stats.ouodchunks++; 1132 else 1133 ctx->asoc->stats.oodchunks++; 1134 1135 /* Only now it's safe to consider this 1136 * chunk as sent, sched-wise. 1137 */ 1138 sctp_sched_dequeue_done(ctx->q, chunk); 1139 1140 list_add_tail(&chunk->transmitted_list, 1141 &ctx->transport->transmitted); 1142 1143 sctp_transport_reset_t3_rtx(ctx->transport); 1144 ctx->transport->last_time_sent = jiffies; 1145 1146 /* Only let one DATA chunk get bundled with a 1147 * COOKIE-ECHO chunk. 1148 */ 1149 if (ctx->packet->has_cookie_echo) 1150 break; 1151 } 1152 } 1153 1154 static void sctp_outq_flush_transports(struct sctp_flush_ctx *ctx) 1155 { 1156 struct list_head *ltransport; 1157 struct sctp_packet *packet; 1158 struct sctp_transport *t; 1159 int error = 0; 1160 1161 while ((ltransport = sctp_list_dequeue(&ctx->transport_list)) != NULL) { 1162 t = list_entry(ltransport, struct sctp_transport, send_ready); 1163 packet = &t->packet; 1164 if (!sctp_packet_empty(packet)) { 1165 error = sctp_packet_transmit(packet, ctx->gfp); 1166 if (error < 0) 1167 ctx->q->asoc->base.sk->sk_err = -error; 1168 } 1169 1170 /* Clear the burst limited state, if any */ 1171 sctp_transport_burst_reset(t); 1172 } 1173 } 1174 1175 /* Try to flush an outqueue. 1176 * 1177 * Description: Send everything in q which we legally can, subject to 1178 * congestion limitations. 1179 * * Note: This function can be called from multiple contexts so appropriate 1180 * locking concerns must be made. Today we use the sock lock to protect 1181 * this function. 1182 */ 1183 1184 static void sctp_outq_flush(struct sctp_outq *q, int rtx_timeout, gfp_t gfp) 1185 { 1186 struct sctp_flush_ctx ctx = { 1187 .q = q, 1188 .transport = NULL, 1189 .transport_list = LIST_HEAD_INIT(ctx.transport_list), 1190 .asoc = q->asoc, 1191 .packet = NULL, 1192 .gfp = gfp, 1193 }; 1194 1195 /* 6.10 Bundling 1196 * ... 1197 * When bundling control chunks with DATA chunks, an 1198 * endpoint MUST place control chunks first in the outbound 1199 * SCTP packet. The transmitter MUST transmit DATA chunks 1200 * within a SCTP packet in increasing order of TSN. 1201 * ... 1202 */ 1203 1204 sctp_outq_flush_ctrl(&ctx); 1205 1206 if (q->asoc->src_out_of_asoc_ok) 1207 goto sctp_flush_out; 1208 1209 sctp_outq_flush_data(&ctx, rtx_timeout); 1210 1211 sctp_flush_out: 1212 1213 sctp_outq_flush_transports(&ctx); 1214 } 1215 1216 /* Update unack_data based on the incoming SACK chunk */ 1217 static void sctp_sack_update_unack_data(struct sctp_association *assoc, 1218 struct sctp_sackhdr *sack) 1219 { 1220 union sctp_sack_variable *frags; 1221 __u16 unack_data; 1222 int i; 1223 1224 unack_data = assoc->next_tsn - assoc->ctsn_ack_point - 1; 1225 1226 frags = sack->variable; 1227 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); i++) { 1228 unack_data -= ((ntohs(frags[i].gab.end) - 1229 ntohs(frags[i].gab.start) + 1)); 1230 } 1231 1232 assoc->unack_data = unack_data; 1233 } 1234 1235 /* This is where we REALLY process a SACK. 1236 * 1237 * Process the SACK against the outqueue. Mostly, this just frees 1238 * things off the transmitted queue. 1239 */ 1240 int sctp_outq_sack(struct sctp_outq *q, struct sctp_chunk *chunk) 1241 { 1242 struct sctp_association *asoc = q->asoc; 1243 struct sctp_sackhdr *sack = chunk->subh.sack_hdr; 1244 struct sctp_transport *transport; 1245 struct sctp_chunk *tchunk = NULL; 1246 struct list_head *lchunk, *transport_list, *temp; 1247 union sctp_sack_variable *frags = sack->variable; 1248 __u32 sack_ctsn, ctsn, tsn; 1249 __u32 highest_tsn, highest_new_tsn; 1250 __u32 sack_a_rwnd; 1251 unsigned int outstanding; 1252 struct sctp_transport *primary = asoc->peer.primary_path; 1253 int count_of_newacks = 0; 1254 int gap_ack_blocks; 1255 u8 accum_moved = 0; 1256 1257 /* Grab the association's destination address list. */ 1258 transport_list = &asoc->peer.transport_addr_list; 1259 1260 sack_ctsn = ntohl(sack->cum_tsn_ack); 1261 gap_ack_blocks = ntohs(sack->num_gap_ack_blocks); 1262 asoc->stats.gapcnt += gap_ack_blocks; 1263 /* 1264 * SFR-CACC algorithm: 1265 * On receipt of a SACK the sender SHOULD execute the 1266 * following statements. 1267 * 1268 * 1) If the cumulative ack in the SACK passes next tsn_at_change 1269 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be 1270 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for 1271 * all destinations. 1272 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE 1273 * is set the receiver of the SACK MUST take the following actions: 1274 * 1275 * A) Initialize the cacc_saw_newack to 0 for all destination 1276 * addresses. 1277 * 1278 * Only bother if changeover_active is set. Otherwise, this is 1279 * totally suboptimal to do on every SACK. 1280 */ 1281 if (primary->cacc.changeover_active) { 1282 u8 clear_cycling = 0; 1283 1284 if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) { 1285 primary->cacc.changeover_active = 0; 1286 clear_cycling = 1; 1287 } 1288 1289 if (clear_cycling || gap_ack_blocks) { 1290 list_for_each_entry(transport, transport_list, 1291 transports) { 1292 if (clear_cycling) 1293 transport->cacc.cycling_changeover = 0; 1294 if (gap_ack_blocks) 1295 transport->cacc.cacc_saw_newack = 0; 1296 } 1297 } 1298 } 1299 1300 /* Get the highest TSN in the sack. */ 1301 highest_tsn = sack_ctsn; 1302 if (gap_ack_blocks) 1303 highest_tsn += ntohs(frags[gap_ack_blocks - 1].gab.end); 1304 1305 if (TSN_lt(asoc->highest_sacked, highest_tsn)) 1306 asoc->highest_sacked = highest_tsn; 1307 1308 highest_new_tsn = sack_ctsn; 1309 1310 /* Run through the retransmit queue. Credit bytes received 1311 * and free those chunks that we can. 1312 */ 1313 sctp_check_transmitted(q, &q->retransmit, NULL, NULL, sack, &highest_new_tsn); 1314 1315 /* Run through the transmitted queue. 1316 * Credit bytes received and free those chunks which we can. 1317 * 1318 * This is a MASSIVE candidate for optimization. 1319 */ 1320 list_for_each_entry(transport, transport_list, transports) { 1321 sctp_check_transmitted(q, &transport->transmitted, 1322 transport, &chunk->source, sack, 1323 &highest_new_tsn); 1324 /* 1325 * SFR-CACC algorithm: 1326 * C) Let count_of_newacks be the number of 1327 * destinations for which cacc_saw_newack is set. 1328 */ 1329 if (transport->cacc.cacc_saw_newack) 1330 count_of_newacks++; 1331 } 1332 1333 /* Move the Cumulative TSN Ack Point if appropriate. */ 1334 if (TSN_lt(asoc->ctsn_ack_point, sack_ctsn)) { 1335 asoc->ctsn_ack_point = sack_ctsn; 1336 accum_moved = 1; 1337 } 1338 1339 if (gap_ack_blocks) { 1340 1341 if (asoc->fast_recovery && accum_moved) 1342 highest_new_tsn = highest_tsn; 1343 1344 list_for_each_entry(transport, transport_list, transports) 1345 sctp_mark_missing(q, &transport->transmitted, transport, 1346 highest_new_tsn, count_of_newacks); 1347 } 1348 1349 /* Update unack_data field in the assoc. */ 1350 sctp_sack_update_unack_data(asoc, sack); 1351 1352 ctsn = asoc->ctsn_ack_point; 1353 1354 /* Throw away stuff rotting on the sack queue. */ 1355 list_for_each_safe(lchunk, temp, &q->sacked) { 1356 tchunk = list_entry(lchunk, struct sctp_chunk, 1357 transmitted_list); 1358 tsn = ntohl(tchunk->subh.data_hdr->tsn); 1359 if (TSN_lte(tsn, ctsn)) { 1360 list_del_init(&tchunk->transmitted_list); 1361 if (asoc->peer.prsctp_capable && 1362 SCTP_PR_PRIO_ENABLED(chunk->sinfo.sinfo_flags)) 1363 asoc->sent_cnt_removable--; 1364 sctp_chunk_free(tchunk); 1365 } 1366 } 1367 1368 /* ii) Set rwnd equal to the newly received a_rwnd minus the 1369 * number of bytes still outstanding after processing the 1370 * Cumulative TSN Ack and the Gap Ack Blocks. 1371 */ 1372 1373 sack_a_rwnd = ntohl(sack->a_rwnd); 1374 asoc->peer.zero_window_announced = !sack_a_rwnd; 1375 outstanding = q->outstanding_bytes; 1376 1377 if (outstanding < sack_a_rwnd) 1378 sack_a_rwnd -= outstanding; 1379 else 1380 sack_a_rwnd = 0; 1381 1382 asoc->peer.rwnd = sack_a_rwnd; 1383 1384 asoc->stream.si->generate_ftsn(q, sack_ctsn); 1385 1386 pr_debug("%s: sack cumulative tsn ack:0x%x\n", __func__, sack_ctsn); 1387 pr_debug("%s: cumulative tsn ack of assoc:%p is 0x%x, " 1388 "advertised peer ack point:0x%x\n", __func__, asoc, ctsn, 1389 asoc->adv_peer_ack_point); 1390 1391 return sctp_outq_is_empty(q); 1392 } 1393 1394 /* Is the outqueue empty? 1395 * The queue is empty when we have not pending data, no in-flight data 1396 * and nothing pending retransmissions. 1397 */ 1398 int sctp_outq_is_empty(const struct sctp_outq *q) 1399 { 1400 return q->out_qlen == 0 && q->outstanding_bytes == 0 && 1401 list_empty(&q->retransmit); 1402 } 1403 1404 /******************************************************************** 1405 * 2nd Level Abstractions 1406 ********************************************************************/ 1407 1408 /* Go through a transport's transmitted list or the association's retransmit 1409 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked. 1410 * The retransmit list will not have an associated transport. 1411 * 1412 * I added coherent debug information output. --xguo 1413 * 1414 * Instead of printing 'sacked' or 'kept' for each TSN on the 1415 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5. 1416 * KEPT TSN6-TSN7, etc. 1417 */ 1418 static void sctp_check_transmitted(struct sctp_outq *q, 1419 struct list_head *transmitted_queue, 1420 struct sctp_transport *transport, 1421 union sctp_addr *saddr, 1422 struct sctp_sackhdr *sack, 1423 __u32 *highest_new_tsn_in_sack) 1424 { 1425 struct list_head *lchunk; 1426 struct sctp_chunk *tchunk; 1427 struct list_head tlist; 1428 __u32 tsn; 1429 __u32 sack_ctsn; 1430 __u32 rtt; 1431 __u8 restart_timer = 0; 1432 int bytes_acked = 0; 1433 int migrate_bytes = 0; 1434 bool forward_progress = false; 1435 1436 sack_ctsn = ntohl(sack->cum_tsn_ack); 1437 1438 INIT_LIST_HEAD(&tlist); 1439 1440 /* The while loop will skip empty transmitted queues. */ 1441 while (NULL != (lchunk = sctp_list_dequeue(transmitted_queue))) { 1442 tchunk = list_entry(lchunk, struct sctp_chunk, 1443 transmitted_list); 1444 1445 if (sctp_chunk_abandoned(tchunk)) { 1446 /* Move the chunk to abandoned list. */ 1447 sctp_insert_list(&q->abandoned, lchunk); 1448 1449 /* If this chunk has not been acked, stop 1450 * considering it as 'outstanding'. 1451 */ 1452 if (transmitted_queue != &q->retransmit && 1453 !tchunk->tsn_gap_acked) { 1454 if (tchunk->transport) 1455 tchunk->transport->flight_size -= 1456 sctp_data_size(tchunk); 1457 q->outstanding_bytes -= sctp_data_size(tchunk); 1458 } 1459 continue; 1460 } 1461 1462 tsn = ntohl(tchunk->subh.data_hdr->tsn); 1463 if (sctp_acked(sack, tsn)) { 1464 /* If this queue is the retransmit queue, the 1465 * retransmit timer has already reclaimed 1466 * the outstanding bytes for this chunk, so only 1467 * count bytes associated with a transport. 1468 */ 1469 if (transport && !tchunk->tsn_gap_acked) { 1470 /* If this chunk is being used for RTT 1471 * measurement, calculate the RTT and update 1472 * the RTO using this value. 1473 * 1474 * 6.3.1 C5) Karn's algorithm: RTT measurements 1475 * MUST NOT be made using packets that were 1476 * retransmitted (and thus for which it is 1477 * ambiguous whether the reply was for the 1478 * first instance of the packet or a later 1479 * instance). 1480 */ 1481 if (!sctp_chunk_retransmitted(tchunk) && 1482 tchunk->rtt_in_progress) { 1483 tchunk->rtt_in_progress = 0; 1484 rtt = jiffies - tchunk->sent_at; 1485 sctp_transport_update_rto(transport, 1486 rtt); 1487 } 1488 1489 if (TSN_lte(tsn, sack_ctsn)) { 1490 /* 1491 * SFR-CACC algorithm: 1492 * 2) If the SACK contains gap acks 1493 * and the flag CHANGEOVER_ACTIVE is 1494 * set the receiver of the SACK MUST 1495 * take the following action: 1496 * 1497 * B) For each TSN t being acked that 1498 * has not been acked in any SACK so 1499 * far, set cacc_saw_newack to 1 for 1500 * the destination that the TSN was 1501 * sent to. 1502 */ 1503 if (sack->num_gap_ack_blocks && 1504 q->asoc->peer.primary_path->cacc. 1505 changeover_active) 1506 transport->cacc.cacc_saw_newack 1507 = 1; 1508 } 1509 } 1510 1511 /* If the chunk hasn't been marked as ACKED, 1512 * mark it and account bytes_acked if the 1513 * chunk had a valid transport (it will not 1514 * have a transport if ASCONF had deleted it 1515 * while DATA was outstanding). 1516 */ 1517 if (!tchunk->tsn_gap_acked) { 1518 tchunk->tsn_gap_acked = 1; 1519 if (TSN_lt(*highest_new_tsn_in_sack, tsn)) 1520 *highest_new_tsn_in_sack = tsn; 1521 bytes_acked += sctp_data_size(tchunk); 1522 if (!tchunk->transport) 1523 migrate_bytes += sctp_data_size(tchunk); 1524 forward_progress = true; 1525 } 1526 1527 if (TSN_lte(tsn, sack_ctsn)) { 1528 /* RFC 2960 6.3.2 Retransmission Timer Rules 1529 * 1530 * R3) Whenever a SACK is received 1531 * that acknowledges the DATA chunk 1532 * with the earliest outstanding TSN 1533 * for that address, restart T3-rtx 1534 * timer for that address with its 1535 * current RTO. 1536 */ 1537 restart_timer = 1; 1538 forward_progress = true; 1539 1540 list_add_tail(&tchunk->transmitted_list, 1541 &q->sacked); 1542 } else { 1543 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2 1544 * M2) Each time a SACK arrives reporting 1545 * 'Stray DATA chunk(s)' record the highest TSN 1546 * reported as newly acknowledged, call this 1547 * value 'HighestTSNinSack'. A newly 1548 * acknowledged DATA chunk is one not 1549 * previously acknowledged in a SACK. 1550 * 1551 * When the SCTP sender of data receives a SACK 1552 * chunk that acknowledges, for the first time, 1553 * the receipt of a DATA chunk, all the still 1554 * unacknowledged DATA chunks whose TSN is 1555 * older than that newly acknowledged DATA 1556 * chunk, are qualified as 'Stray DATA chunks'. 1557 */ 1558 list_add_tail(lchunk, &tlist); 1559 } 1560 } else { 1561 if (tchunk->tsn_gap_acked) { 1562 pr_debug("%s: receiver reneged on data TSN:0x%x\n", 1563 __func__, tsn); 1564 1565 tchunk->tsn_gap_acked = 0; 1566 1567 if (tchunk->transport) 1568 bytes_acked -= sctp_data_size(tchunk); 1569 1570 /* RFC 2960 6.3.2 Retransmission Timer Rules 1571 * 1572 * R4) Whenever a SACK is received missing a 1573 * TSN that was previously acknowledged via a 1574 * Gap Ack Block, start T3-rtx for the 1575 * destination address to which the DATA 1576 * chunk was originally 1577 * transmitted if it is not already running. 1578 */ 1579 restart_timer = 1; 1580 } 1581 1582 list_add_tail(lchunk, &tlist); 1583 } 1584 } 1585 1586 if (transport) { 1587 if (bytes_acked) { 1588 struct sctp_association *asoc = transport->asoc; 1589 1590 /* We may have counted DATA that was migrated 1591 * to this transport due to DEL-IP operation. 1592 * Subtract those bytes, since the were never 1593 * send on this transport and shouldn't be 1594 * credited to this transport. 1595 */ 1596 bytes_acked -= migrate_bytes; 1597 1598 /* 8.2. When an outstanding TSN is acknowledged, 1599 * the endpoint shall clear the error counter of 1600 * the destination transport address to which the 1601 * DATA chunk was last sent. 1602 * The association's overall error counter is 1603 * also cleared. 1604 */ 1605 transport->error_count = 0; 1606 transport->asoc->overall_error_count = 0; 1607 forward_progress = true; 1608 1609 /* 1610 * While in SHUTDOWN PENDING, we may have started 1611 * the T5 shutdown guard timer after reaching the 1612 * retransmission limit. Stop that timer as soon 1613 * as the receiver acknowledged any data. 1614 */ 1615 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING && 1616 del_timer(&asoc->timers 1617 [SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD])) 1618 sctp_association_put(asoc); 1619 1620 /* Mark the destination transport address as 1621 * active if it is not so marked. 1622 */ 1623 if ((transport->state == SCTP_INACTIVE || 1624 transport->state == SCTP_UNCONFIRMED) && 1625 sctp_cmp_addr_exact(&transport->ipaddr, saddr)) { 1626 sctp_assoc_control_transport( 1627 transport->asoc, 1628 transport, 1629 SCTP_TRANSPORT_UP, 1630 SCTP_RECEIVED_SACK); 1631 } 1632 1633 sctp_transport_raise_cwnd(transport, sack_ctsn, 1634 bytes_acked); 1635 1636 transport->flight_size -= bytes_acked; 1637 if (transport->flight_size == 0) 1638 transport->partial_bytes_acked = 0; 1639 q->outstanding_bytes -= bytes_acked + migrate_bytes; 1640 } else { 1641 /* RFC 2960 6.1, sctpimpguide-06 2.15.2 1642 * When a sender is doing zero window probing, it 1643 * should not timeout the association if it continues 1644 * to receive new packets from the receiver. The 1645 * reason is that the receiver MAY keep its window 1646 * closed for an indefinite time. 1647 * A sender is doing zero window probing when the 1648 * receiver's advertised window is zero, and there is 1649 * only one data chunk in flight to the receiver. 1650 * 1651 * Allow the association to timeout while in SHUTDOWN 1652 * PENDING or SHUTDOWN RECEIVED in case the receiver 1653 * stays in zero window mode forever. 1654 */ 1655 if (!q->asoc->peer.rwnd && 1656 !list_empty(&tlist) && 1657 (sack_ctsn+2 == q->asoc->next_tsn) && 1658 q->asoc->state < SCTP_STATE_SHUTDOWN_PENDING) { 1659 pr_debug("%s: sack received for zero window " 1660 "probe:%u\n", __func__, sack_ctsn); 1661 1662 q->asoc->overall_error_count = 0; 1663 transport->error_count = 0; 1664 } 1665 } 1666 1667 /* RFC 2960 6.3.2 Retransmission Timer Rules 1668 * 1669 * R2) Whenever all outstanding data sent to an address have 1670 * been acknowledged, turn off the T3-rtx timer of that 1671 * address. 1672 */ 1673 if (!transport->flight_size) { 1674 if (del_timer(&transport->T3_rtx_timer)) 1675 sctp_transport_put(transport); 1676 } else if (restart_timer) { 1677 if (!mod_timer(&transport->T3_rtx_timer, 1678 jiffies + transport->rto)) 1679 sctp_transport_hold(transport); 1680 } 1681 1682 if (forward_progress) { 1683 if (transport->dst) 1684 sctp_transport_dst_confirm(transport); 1685 } 1686 } 1687 1688 list_splice(&tlist, transmitted_queue); 1689 } 1690 1691 /* Mark chunks as missing and consequently may get retransmitted. */ 1692 static void sctp_mark_missing(struct sctp_outq *q, 1693 struct list_head *transmitted_queue, 1694 struct sctp_transport *transport, 1695 __u32 highest_new_tsn_in_sack, 1696 int count_of_newacks) 1697 { 1698 struct sctp_chunk *chunk; 1699 __u32 tsn; 1700 char do_fast_retransmit = 0; 1701 struct sctp_association *asoc = q->asoc; 1702 struct sctp_transport *primary = asoc->peer.primary_path; 1703 1704 list_for_each_entry(chunk, transmitted_queue, transmitted_list) { 1705 1706 tsn = ntohl(chunk->subh.data_hdr->tsn); 1707 1708 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all 1709 * 'Unacknowledged TSN's', if the TSN number of an 1710 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack' 1711 * value, increment the 'TSN.Missing.Report' count on that 1712 * chunk if it has NOT been fast retransmitted or marked for 1713 * fast retransmit already. 1714 */ 1715 if (chunk->fast_retransmit == SCTP_CAN_FRTX && 1716 !chunk->tsn_gap_acked && 1717 TSN_lt(tsn, highest_new_tsn_in_sack)) { 1718 1719 /* SFR-CACC may require us to skip marking 1720 * this chunk as missing. 1721 */ 1722 if (!transport || !sctp_cacc_skip(primary, 1723 chunk->transport, 1724 count_of_newacks, tsn)) { 1725 chunk->tsn_missing_report++; 1726 1727 pr_debug("%s: tsn:0x%x missing counter:%d\n", 1728 __func__, tsn, chunk->tsn_missing_report); 1729 } 1730 } 1731 /* 1732 * M4) If any DATA chunk is found to have a 1733 * 'TSN.Missing.Report' 1734 * value larger than or equal to 3, mark that chunk for 1735 * retransmission and start the fast retransmit procedure. 1736 */ 1737 1738 if (chunk->tsn_missing_report >= 3) { 1739 chunk->fast_retransmit = SCTP_NEED_FRTX; 1740 do_fast_retransmit = 1; 1741 } 1742 } 1743 1744 if (transport) { 1745 if (do_fast_retransmit) 1746 sctp_retransmit(q, transport, SCTP_RTXR_FAST_RTX); 1747 1748 pr_debug("%s: transport:%p, cwnd:%d, ssthresh:%d, " 1749 "flight_size:%d, pba:%d\n", __func__, transport, 1750 transport->cwnd, transport->ssthresh, 1751 transport->flight_size, transport->partial_bytes_acked); 1752 } 1753 } 1754 1755 /* Is the given TSN acked by this packet? */ 1756 static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn) 1757 { 1758 __u32 ctsn = ntohl(sack->cum_tsn_ack); 1759 union sctp_sack_variable *frags; 1760 __u16 tsn_offset, blocks; 1761 int i; 1762 1763 if (TSN_lte(tsn, ctsn)) 1764 goto pass; 1765 1766 /* 3.3.4 Selective Acknowledgment (SACK) (3): 1767 * 1768 * Gap Ack Blocks: 1769 * These fields contain the Gap Ack Blocks. They are repeated 1770 * for each Gap Ack Block up to the number of Gap Ack Blocks 1771 * defined in the Number of Gap Ack Blocks field. All DATA 1772 * chunks with TSNs greater than or equal to (Cumulative TSN 1773 * Ack + Gap Ack Block Start) and less than or equal to 1774 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack 1775 * Block are assumed to have been received correctly. 1776 */ 1777 1778 frags = sack->variable; 1779 blocks = ntohs(sack->num_gap_ack_blocks); 1780 tsn_offset = tsn - ctsn; 1781 for (i = 0; i < blocks; ++i) { 1782 if (tsn_offset >= ntohs(frags[i].gab.start) && 1783 tsn_offset <= ntohs(frags[i].gab.end)) 1784 goto pass; 1785 } 1786 1787 return 0; 1788 pass: 1789 return 1; 1790 } 1791 1792 static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip *skiplist, 1793 int nskips, __be16 stream) 1794 { 1795 int i; 1796 1797 for (i = 0; i < nskips; i++) { 1798 if (skiplist[i].stream == stream) 1799 return i; 1800 } 1801 return i; 1802 } 1803 1804 /* Create and add a fwdtsn chunk to the outq's control queue if needed. */ 1805 void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 ctsn) 1806 { 1807 struct sctp_association *asoc = q->asoc; 1808 struct sctp_chunk *ftsn_chunk = NULL; 1809 struct sctp_fwdtsn_skip ftsn_skip_arr[10]; 1810 int nskips = 0; 1811 int skip_pos = 0; 1812 __u32 tsn; 1813 struct sctp_chunk *chunk; 1814 struct list_head *lchunk, *temp; 1815 1816 if (!asoc->peer.prsctp_capable) 1817 return; 1818 1819 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the 1820 * received SACK. 1821 * 1822 * If (Advanced.Peer.Ack.Point < SackCumAck), then update 1823 * Advanced.Peer.Ack.Point to be equal to SackCumAck. 1824 */ 1825 if (TSN_lt(asoc->adv_peer_ack_point, ctsn)) 1826 asoc->adv_peer_ack_point = ctsn; 1827 1828 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point" 1829 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as 1830 * the chunk next in the out-queue space is marked as "abandoned" as 1831 * shown in the following example: 1832 * 1833 * Assuming that a SACK arrived with the Cumulative TSN ACK 102 1834 * and the Advanced.Peer.Ack.Point is updated to this value: 1835 * 1836 * out-queue at the end of ==> out-queue after Adv.Ack.Point 1837 * normal SACK processing local advancement 1838 * ... ... 1839 * Adv.Ack.Pt-> 102 acked 102 acked 1840 * 103 abandoned 103 abandoned 1841 * 104 abandoned Adv.Ack.P-> 104 abandoned 1842 * 105 105 1843 * 106 acked 106 acked 1844 * ... ... 1845 * 1846 * In this example, the data sender successfully advanced the 1847 * "Advanced.Peer.Ack.Point" from 102 to 104 locally. 1848 */ 1849 list_for_each_safe(lchunk, temp, &q->abandoned) { 1850 chunk = list_entry(lchunk, struct sctp_chunk, 1851 transmitted_list); 1852 tsn = ntohl(chunk->subh.data_hdr->tsn); 1853 1854 /* Remove any chunks in the abandoned queue that are acked by 1855 * the ctsn. 1856 */ 1857 if (TSN_lte(tsn, ctsn)) { 1858 list_del_init(lchunk); 1859 sctp_chunk_free(chunk); 1860 } else { 1861 if (TSN_lte(tsn, asoc->adv_peer_ack_point+1)) { 1862 asoc->adv_peer_ack_point = tsn; 1863 if (chunk->chunk_hdr->flags & 1864 SCTP_DATA_UNORDERED) 1865 continue; 1866 skip_pos = sctp_get_skip_pos(&ftsn_skip_arr[0], 1867 nskips, 1868 chunk->subh.data_hdr->stream); 1869 ftsn_skip_arr[skip_pos].stream = 1870 chunk->subh.data_hdr->stream; 1871 ftsn_skip_arr[skip_pos].ssn = 1872 chunk->subh.data_hdr->ssn; 1873 if (skip_pos == nskips) 1874 nskips++; 1875 if (nskips == 10) 1876 break; 1877 } else 1878 break; 1879 } 1880 } 1881 1882 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point" 1883 * is greater than the Cumulative TSN ACK carried in the received 1884 * SACK, the data sender MUST send the data receiver a FORWARD TSN 1885 * chunk containing the latest value of the 1886 * "Advanced.Peer.Ack.Point". 1887 * 1888 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD 1889 * list each stream and sequence number in the forwarded TSN. This 1890 * information will enable the receiver to easily find any 1891 * stranded TSN's waiting on stream reorder queues. Each stream 1892 * SHOULD only be reported once; this means that if multiple 1893 * abandoned messages occur in the same stream then only the 1894 * highest abandoned stream sequence number is reported. If the 1895 * total size of the FORWARD TSN does NOT fit in a single MTU then 1896 * the sender of the FORWARD TSN SHOULD lower the 1897 * Advanced.Peer.Ack.Point to the last TSN that will fit in a 1898 * single MTU. 1899 */ 1900 if (asoc->adv_peer_ack_point > ctsn) 1901 ftsn_chunk = sctp_make_fwdtsn(asoc, asoc->adv_peer_ack_point, 1902 nskips, &ftsn_skip_arr[0]); 1903 1904 if (ftsn_chunk) { 1905 list_add_tail(&ftsn_chunk->list, &q->control_chunk_list); 1906 SCTP_INC_STATS(sock_net(asoc->base.sk), SCTP_MIB_OUTCTRLCHUNKS); 1907 } 1908 } 1909