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