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 54 /* Declare internal functions here. */ 55 static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn); 56 static void sctp_check_transmitted(struct sctp_outq *q, 57 struct list_head *transmitted_queue, 58 struct sctp_transport *transport, 59 union sctp_addr *saddr, 60 struct sctp_sackhdr *sack, 61 __u32 *highest_new_tsn); 62 63 static void sctp_mark_missing(struct sctp_outq *q, 64 struct list_head *transmitted_queue, 65 struct sctp_transport *transport, 66 __u32 highest_new_tsn, 67 int count_of_newacks); 68 69 static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 sack_ctsn); 70 71 static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout); 72 73 /* Add data to the front of the queue. */ 74 static inline void sctp_outq_head_data(struct sctp_outq *q, 75 struct sctp_chunk *ch) 76 { 77 list_add(&ch->list, &q->out_chunk_list); 78 q->out_qlen += ch->skb->len; 79 } 80 81 /* Take data from the front of the queue. */ 82 static inline struct sctp_chunk *sctp_outq_dequeue_data(struct sctp_outq *q) 83 { 84 struct sctp_chunk *ch = NULL; 85 86 if (!list_empty(&q->out_chunk_list)) { 87 struct list_head *entry = q->out_chunk_list.next; 88 89 ch = list_entry(entry, struct sctp_chunk, list); 90 list_del_init(entry); 91 q->out_qlen -= ch->skb->len; 92 } 93 return ch; 94 } 95 /* Add data chunk to the end of the queue. */ 96 static inline void sctp_outq_tail_data(struct sctp_outq *q, 97 struct sctp_chunk *ch) 98 { 99 list_add_tail(&ch->list, &q->out_chunk_list); 100 q->out_qlen += ch->skb->len; 101 } 102 103 /* 104 * SFR-CACC algorithm: 105 * D) If count_of_newacks is greater than or equal to 2 106 * and t was not sent to the current primary then the 107 * sender MUST NOT increment missing report count for t. 108 */ 109 static inline int sctp_cacc_skip_3_1_d(struct sctp_transport *primary, 110 struct sctp_transport *transport, 111 int count_of_newacks) 112 { 113 if (count_of_newacks >= 2 && transport != primary) 114 return 1; 115 return 0; 116 } 117 118 /* 119 * SFR-CACC algorithm: 120 * F) If count_of_newacks is less than 2, let d be the 121 * destination to which t was sent. If cacc_saw_newack 122 * is 0 for destination d, then the sender MUST NOT 123 * increment missing report count for t. 124 */ 125 static inline int sctp_cacc_skip_3_1_f(struct sctp_transport *transport, 126 int count_of_newacks) 127 { 128 if (count_of_newacks < 2 && 129 (transport && !transport->cacc.cacc_saw_newack)) 130 return 1; 131 return 0; 132 } 133 134 /* 135 * SFR-CACC algorithm: 136 * 3.1) If CYCLING_CHANGEOVER is 0, the sender SHOULD 137 * execute steps C, D, F. 138 * 139 * C has been implemented in sctp_outq_sack 140 */ 141 static inline int sctp_cacc_skip_3_1(struct sctp_transport *primary, 142 struct sctp_transport *transport, 143 int count_of_newacks) 144 { 145 if (!primary->cacc.cycling_changeover) { 146 if (sctp_cacc_skip_3_1_d(primary, transport, count_of_newacks)) 147 return 1; 148 if (sctp_cacc_skip_3_1_f(transport, count_of_newacks)) 149 return 1; 150 return 0; 151 } 152 return 0; 153 } 154 155 /* 156 * SFR-CACC algorithm: 157 * 3.2) Else if CYCLING_CHANGEOVER is 1, and t is less 158 * than next_tsn_at_change of the current primary, then 159 * the sender MUST NOT increment missing report count 160 * for t. 161 */ 162 static inline int sctp_cacc_skip_3_2(struct sctp_transport *primary, __u32 tsn) 163 { 164 if (primary->cacc.cycling_changeover && 165 TSN_lt(tsn, primary->cacc.next_tsn_at_change)) 166 return 1; 167 return 0; 168 } 169 170 /* 171 * SFR-CACC algorithm: 172 * 3) If the missing report count for TSN t is to be 173 * incremented according to [RFC2960] and 174 * [SCTP_STEWART-2002], and CHANGEOVER_ACTIVE is set, 175 * then the sender MUST further execute steps 3.1 and 176 * 3.2 to determine if the missing report count for 177 * TSN t SHOULD NOT be incremented. 178 * 179 * 3.3) If 3.1 and 3.2 do not dictate that the missing 180 * report count for t should not be incremented, then 181 * the sender SHOULD increment missing report count for 182 * t (according to [RFC2960] and [SCTP_STEWART_2002]). 183 */ 184 static inline int sctp_cacc_skip(struct sctp_transport *primary, 185 struct sctp_transport *transport, 186 int count_of_newacks, 187 __u32 tsn) 188 { 189 if (primary->cacc.changeover_active && 190 (sctp_cacc_skip_3_1(primary, transport, count_of_newacks) || 191 sctp_cacc_skip_3_2(primary, tsn))) 192 return 1; 193 return 0; 194 } 195 196 /* Initialize an existing sctp_outq. This does the boring stuff. 197 * You still need to define handlers if you really want to DO 198 * something with this structure... 199 */ 200 void sctp_outq_init(struct sctp_association *asoc, struct sctp_outq *q) 201 { 202 memset(q, 0, sizeof(struct sctp_outq)); 203 204 q->asoc = asoc; 205 INIT_LIST_HEAD(&q->out_chunk_list); 206 INIT_LIST_HEAD(&q->control_chunk_list); 207 INIT_LIST_HEAD(&q->retransmit); 208 INIT_LIST_HEAD(&q->sacked); 209 INIT_LIST_HEAD(&q->abandoned); 210 211 q->empty = 1; 212 } 213 214 /* Free the outqueue structure and any related pending chunks. 215 */ 216 static void __sctp_outq_teardown(struct sctp_outq *q) 217 { 218 struct sctp_transport *transport; 219 struct list_head *lchunk, *temp; 220 struct sctp_chunk *chunk, *tmp; 221 222 /* Throw away unacknowledged chunks. */ 223 list_for_each_entry(transport, &q->asoc->peer.transport_addr_list, 224 transports) { 225 while ((lchunk = sctp_list_dequeue(&transport->transmitted)) != NULL) { 226 chunk = list_entry(lchunk, struct sctp_chunk, 227 transmitted_list); 228 /* Mark as part of a failed message. */ 229 sctp_chunk_fail(chunk, q->error); 230 sctp_chunk_free(chunk); 231 } 232 } 233 234 /* Throw away chunks that have been gap ACKed. */ 235 list_for_each_safe(lchunk, temp, &q->sacked) { 236 list_del_init(lchunk); 237 chunk = list_entry(lchunk, struct sctp_chunk, 238 transmitted_list); 239 sctp_chunk_fail(chunk, q->error); 240 sctp_chunk_free(chunk); 241 } 242 243 /* Throw away any chunks in the retransmit queue. */ 244 list_for_each_safe(lchunk, temp, &q->retransmit) { 245 list_del_init(lchunk); 246 chunk = list_entry(lchunk, struct sctp_chunk, 247 transmitted_list); 248 sctp_chunk_fail(chunk, q->error); 249 sctp_chunk_free(chunk); 250 } 251 252 /* Throw away any chunks that are in the abandoned queue. */ 253 list_for_each_safe(lchunk, temp, &q->abandoned) { 254 list_del_init(lchunk); 255 chunk = list_entry(lchunk, struct sctp_chunk, 256 transmitted_list); 257 sctp_chunk_fail(chunk, q->error); 258 sctp_chunk_free(chunk); 259 } 260 261 /* Throw away any leftover data chunks. */ 262 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) { 263 264 /* Mark as send failure. */ 265 sctp_chunk_fail(chunk, q->error); 266 sctp_chunk_free(chunk); 267 } 268 269 /* Throw away any leftover control chunks. */ 270 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) { 271 list_del_init(&chunk->list); 272 sctp_chunk_free(chunk); 273 } 274 } 275 276 void sctp_outq_teardown(struct sctp_outq *q) 277 { 278 __sctp_outq_teardown(q); 279 sctp_outq_init(q->asoc, q); 280 } 281 282 /* Free the outqueue structure and any related pending chunks. */ 283 void sctp_outq_free(struct sctp_outq *q) 284 { 285 /* Throw away leftover chunks. */ 286 __sctp_outq_teardown(q); 287 } 288 289 /* Put a new chunk in an sctp_outq. */ 290 int sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk) 291 { 292 struct net *net = sock_net(q->asoc->base.sk); 293 int error = 0; 294 295 pr_debug("%s: outq:%p, chunk:%p[%s]\n", __func__, q, chunk, 296 chunk && chunk->chunk_hdr ? 297 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) : 298 "illegal chunk"); 299 300 /* If it is data, queue it up, otherwise, send it 301 * immediately. 302 */ 303 if (sctp_chunk_is_data(chunk)) { 304 /* Is it OK to queue data chunks? */ 305 /* From 9. Termination of Association 306 * 307 * When either endpoint performs a shutdown, the 308 * association on each peer will stop accepting new 309 * data from its user and only deliver data in queue 310 * at the time of sending or receiving the SHUTDOWN 311 * chunk. 312 */ 313 switch (q->asoc->state) { 314 case SCTP_STATE_CLOSED: 315 case SCTP_STATE_SHUTDOWN_PENDING: 316 case SCTP_STATE_SHUTDOWN_SENT: 317 case SCTP_STATE_SHUTDOWN_RECEIVED: 318 case SCTP_STATE_SHUTDOWN_ACK_SENT: 319 /* Cannot send after transport endpoint shutdown */ 320 error = -ESHUTDOWN; 321 break; 322 323 default: 324 pr_debug("%s: outqueueing: outq:%p, chunk:%p[%s])\n", 325 __func__, q, chunk, chunk && chunk->chunk_hdr ? 326 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) : 327 "illegal chunk"); 328 329 sctp_outq_tail_data(q, chunk); 330 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) 331 SCTP_INC_STATS(net, SCTP_MIB_OUTUNORDERCHUNKS); 332 else 333 SCTP_INC_STATS(net, SCTP_MIB_OUTORDERCHUNKS); 334 q->empty = 0; 335 break; 336 } 337 } else { 338 list_add_tail(&chunk->list, &q->control_chunk_list); 339 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 340 } 341 342 if (error < 0) 343 return error; 344 345 if (!q->cork) 346 error = sctp_outq_flush(q, 0); 347 348 return error; 349 } 350 351 /* Insert a chunk into the sorted list based on the TSNs. The retransmit list 352 * and the abandoned list are in ascending order. 353 */ 354 static void sctp_insert_list(struct list_head *head, struct list_head *new) 355 { 356 struct list_head *pos; 357 struct sctp_chunk *nchunk, *lchunk; 358 __u32 ntsn, ltsn; 359 int done = 0; 360 361 nchunk = list_entry(new, struct sctp_chunk, transmitted_list); 362 ntsn = ntohl(nchunk->subh.data_hdr->tsn); 363 364 list_for_each(pos, head) { 365 lchunk = list_entry(pos, struct sctp_chunk, transmitted_list); 366 ltsn = ntohl(lchunk->subh.data_hdr->tsn); 367 if (TSN_lt(ntsn, ltsn)) { 368 list_add(new, pos->prev); 369 done = 1; 370 break; 371 } 372 } 373 if (!done) 374 list_add_tail(new, head); 375 } 376 377 /* Mark all the eligible packets on a transport for retransmission. */ 378 void sctp_retransmit_mark(struct sctp_outq *q, 379 struct sctp_transport *transport, 380 __u8 reason) 381 { 382 struct list_head *lchunk, *ltemp; 383 struct sctp_chunk *chunk; 384 385 /* Walk through the specified transmitted queue. */ 386 list_for_each_safe(lchunk, ltemp, &transport->transmitted) { 387 chunk = list_entry(lchunk, struct sctp_chunk, 388 transmitted_list); 389 390 /* If the chunk is abandoned, move it to abandoned list. */ 391 if (sctp_chunk_abandoned(chunk)) { 392 list_del_init(lchunk); 393 sctp_insert_list(&q->abandoned, lchunk); 394 395 /* If this chunk has not been previousely acked, 396 * stop considering it 'outstanding'. Our peer 397 * will most likely never see it since it will 398 * not be retransmitted 399 */ 400 if (!chunk->tsn_gap_acked) { 401 if (chunk->transport) 402 chunk->transport->flight_size -= 403 sctp_data_size(chunk); 404 q->outstanding_bytes -= sctp_data_size(chunk); 405 q->asoc->peer.rwnd += sctp_data_size(chunk); 406 } 407 continue; 408 } 409 410 /* If we are doing retransmission due to a timeout or pmtu 411 * discovery, only the chunks that are not yet acked should 412 * be added to the retransmit queue. 413 */ 414 if ((reason == SCTP_RTXR_FAST_RTX && 415 (chunk->fast_retransmit == SCTP_NEED_FRTX)) || 416 (reason != SCTP_RTXR_FAST_RTX && !chunk->tsn_gap_acked)) { 417 /* RFC 2960 6.2.1 Processing a Received SACK 418 * 419 * C) Any time a DATA chunk is marked for 420 * retransmission (via either T3-rtx timer expiration 421 * (Section 6.3.3) or via fast retransmit 422 * (Section 7.2.4)), add the data size of those 423 * chunks to the rwnd. 424 */ 425 q->asoc->peer.rwnd += sctp_data_size(chunk); 426 q->outstanding_bytes -= sctp_data_size(chunk); 427 if (chunk->transport) 428 transport->flight_size -= sctp_data_size(chunk); 429 430 /* sctpimpguide-05 Section 2.8.2 431 * M5) If a T3-rtx timer expires, the 432 * 'TSN.Missing.Report' of all affected TSNs is set 433 * to 0. 434 */ 435 chunk->tsn_missing_report = 0; 436 437 /* If a chunk that is being used for RTT measurement 438 * has to be retransmitted, we cannot use this chunk 439 * anymore for RTT measurements. Reset rto_pending so 440 * that a new RTT measurement is started when a new 441 * data chunk is sent. 442 */ 443 if (chunk->rtt_in_progress) { 444 chunk->rtt_in_progress = 0; 445 transport->rto_pending = 0; 446 } 447 448 chunk->resent = 1; 449 450 /* Move the chunk to the retransmit queue. The chunks 451 * on the retransmit queue are always kept in order. 452 */ 453 list_del_init(lchunk); 454 sctp_insert_list(&q->retransmit, lchunk); 455 } 456 } 457 458 pr_debug("%s: transport:%p, reason:%d, cwnd:%d, ssthresh:%d, " 459 "flight_size:%d, pba:%d\n", __func__, transport, reason, 460 transport->cwnd, transport->ssthresh, transport->flight_size, 461 transport->partial_bytes_acked); 462 } 463 464 /* Mark all the eligible packets on a transport for retransmission and force 465 * one packet out. 466 */ 467 void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport, 468 sctp_retransmit_reason_t reason) 469 { 470 struct net *net = sock_net(q->asoc->base.sk); 471 int error = 0; 472 473 switch (reason) { 474 case SCTP_RTXR_T3_RTX: 475 SCTP_INC_STATS(net, SCTP_MIB_T3_RETRANSMITS); 476 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_T3_RTX); 477 /* Update the retran path if the T3-rtx timer has expired for 478 * the current retran path. 479 */ 480 if (transport == transport->asoc->peer.retran_path) 481 sctp_assoc_update_retran_path(transport->asoc); 482 transport->asoc->rtx_data_chunks += 483 transport->asoc->unack_data; 484 break; 485 case SCTP_RTXR_FAST_RTX: 486 SCTP_INC_STATS(net, SCTP_MIB_FAST_RETRANSMITS); 487 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_FAST_RTX); 488 q->fast_rtx = 1; 489 break; 490 case SCTP_RTXR_PMTUD: 491 SCTP_INC_STATS(net, SCTP_MIB_PMTUD_RETRANSMITS); 492 break; 493 case SCTP_RTXR_T1_RTX: 494 SCTP_INC_STATS(net, SCTP_MIB_T1_RETRANSMITS); 495 transport->asoc->init_retries++; 496 break; 497 default: 498 BUG(); 499 } 500 501 sctp_retransmit_mark(q, transport, reason); 502 503 /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination, 504 * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by 505 * following the procedures outlined in C1 - C5. 506 */ 507 if (reason == SCTP_RTXR_T3_RTX) 508 sctp_generate_fwdtsn(q, q->asoc->ctsn_ack_point); 509 510 /* Flush the queues only on timeout, since fast_rtx is only 511 * triggered during sack processing and the queue 512 * will be flushed at the end. 513 */ 514 if (reason != SCTP_RTXR_FAST_RTX) 515 error = sctp_outq_flush(q, /* rtx_timeout */ 1); 516 517 if (error) 518 q->asoc->base.sk->sk_err = -error; 519 } 520 521 /* 522 * Transmit DATA chunks on the retransmit queue. Upon return from 523 * sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which 524 * need to be transmitted by the caller. 525 * We assume that pkt->transport has already been set. 526 * 527 * The return value is a normal kernel error return value. 528 */ 529 static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt, 530 int rtx_timeout, int *start_timer) 531 { 532 struct list_head *lqueue; 533 struct sctp_transport *transport = pkt->transport; 534 sctp_xmit_t status; 535 struct sctp_chunk *chunk, *chunk1; 536 int fast_rtx; 537 int error = 0; 538 int timer = 0; 539 int done = 0; 540 541 lqueue = &q->retransmit; 542 fast_rtx = q->fast_rtx; 543 544 /* This loop handles time-out retransmissions, fast retransmissions, 545 * and retransmissions due to opening of whindow. 546 * 547 * RFC 2960 6.3.3 Handle T3-rtx Expiration 548 * 549 * E3) Determine how many of the earliest (i.e., lowest TSN) 550 * outstanding DATA chunks for the address for which the 551 * T3-rtx has expired will fit into a single packet, subject 552 * to the MTU constraint for the path corresponding to the 553 * destination transport address to which the retransmission 554 * is being sent (this may be different from the address for 555 * which the timer expires [see Section 6.4]). Call this value 556 * K. Bundle and retransmit those K DATA chunks in a single 557 * packet to the destination endpoint. 558 * 559 * [Just to be painfully clear, if we are retransmitting 560 * because a timeout just happened, we should send only ONE 561 * packet of retransmitted data.] 562 * 563 * For fast retransmissions we also send only ONE packet. However, 564 * if we are just flushing the queue due to open window, we'll 565 * try to send as much as possible. 566 */ 567 list_for_each_entry_safe(chunk, chunk1, lqueue, transmitted_list) { 568 /* If the chunk is abandoned, move it to abandoned list. */ 569 if (sctp_chunk_abandoned(chunk)) { 570 list_del_init(&chunk->transmitted_list); 571 sctp_insert_list(&q->abandoned, 572 &chunk->transmitted_list); 573 continue; 574 } 575 576 /* Make sure that Gap Acked TSNs are not retransmitted. A 577 * simple approach is just to move such TSNs out of the 578 * way and into a 'transmitted' queue and skip to the 579 * next chunk. 580 */ 581 if (chunk->tsn_gap_acked) { 582 list_move_tail(&chunk->transmitted_list, 583 &transport->transmitted); 584 continue; 585 } 586 587 /* If we are doing fast retransmit, ignore non-fast_rtransmit 588 * chunks 589 */ 590 if (fast_rtx && !chunk->fast_retransmit) 591 continue; 592 593 redo: 594 /* Attempt to append this chunk to the packet. */ 595 status = sctp_packet_append_chunk(pkt, chunk); 596 597 switch (status) { 598 case SCTP_XMIT_PMTU_FULL: 599 if (!pkt->has_data && !pkt->has_cookie_echo) { 600 /* If this packet did not contain DATA then 601 * retransmission did not happen, so do it 602 * again. We'll ignore the error here since 603 * control chunks are already freed so there 604 * is nothing we can do. 605 */ 606 sctp_packet_transmit(pkt); 607 goto redo; 608 } 609 610 /* Send this packet. */ 611 error = sctp_packet_transmit(pkt); 612 613 /* If we are retransmitting, we should only 614 * send a single packet. 615 * Otherwise, try appending this chunk again. 616 */ 617 if (rtx_timeout || fast_rtx) 618 done = 1; 619 else 620 goto redo; 621 622 /* Bundle next chunk in the next round. */ 623 break; 624 625 case SCTP_XMIT_RWND_FULL: 626 /* Send this packet. */ 627 error = sctp_packet_transmit(pkt); 628 629 /* Stop sending DATA as there is no more room 630 * at the receiver. 631 */ 632 done = 1; 633 break; 634 635 case SCTP_XMIT_NAGLE_DELAY: 636 /* Send this packet. */ 637 error = sctp_packet_transmit(pkt); 638 639 /* Stop sending DATA because of nagle delay. */ 640 done = 1; 641 break; 642 643 default: 644 /* The append was successful, so add this chunk to 645 * the transmitted list. 646 */ 647 list_move_tail(&chunk->transmitted_list, 648 &transport->transmitted); 649 650 /* Mark the chunk as ineligible for fast retransmit 651 * after it is retransmitted. 652 */ 653 if (chunk->fast_retransmit == SCTP_NEED_FRTX) 654 chunk->fast_retransmit = SCTP_DONT_FRTX; 655 656 q->empty = 0; 657 q->asoc->stats.rtxchunks++; 658 break; 659 } 660 661 /* Set the timer if there were no errors */ 662 if (!error && !timer) 663 timer = 1; 664 665 if (done) 666 break; 667 } 668 669 /* If we are here due to a retransmit timeout or a fast 670 * retransmit and if there are any chunks left in the retransmit 671 * queue that could not fit in the PMTU sized packet, they need 672 * to be marked as ineligible for a subsequent fast retransmit. 673 */ 674 if (rtx_timeout || fast_rtx) { 675 list_for_each_entry(chunk1, lqueue, transmitted_list) { 676 if (chunk1->fast_retransmit == SCTP_NEED_FRTX) 677 chunk1->fast_retransmit = SCTP_DONT_FRTX; 678 } 679 } 680 681 *start_timer = timer; 682 683 /* Clear fast retransmit hint */ 684 if (fast_rtx) 685 q->fast_rtx = 0; 686 687 return error; 688 } 689 690 /* Cork the outqueue so queued chunks are really queued. */ 691 int sctp_outq_uncork(struct sctp_outq *q) 692 { 693 if (q->cork) 694 q->cork = 0; 695 696 return sctp_outq_flush(q, 0); 697 } 698 699 700 /* 701 * Try to flush an outqueue. 702 * 703 * Description: Send everything in q which we legally can, subject to 704 * congestion limitations. 705 * * Note: This function can be called from multiple contexts so appropriate 706 * locking concerns must be made. Today we use the sock lock to protect 707 * this function. 708 */ 709 static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout) 710 { 711 struct sctp_packet *packet; 712 struct sctp_packet singleton; 713 struct sctp_association *asoc = q->asoc; 714 __u16 sport = asoc->base.bind_addr.port; 715 __u16 dport = asoc->peer.port; 716 __u32 vtag = asoc->peer.i.init_tag; 717 struct sctp_transport *transport = NULL; 718 struct sctp_transport *new_transport; 719 struct sctp_chunk *chunk, *tmp; 720 sctp_xmit_t status; 721 int error = 0; 722 int start_timer = 0; 723 int one_packet = 0; 724 725 /* These transports have chunks to send. */ 726 struct list_head transport_list; 727 struct list_head *ltransport; 728 729 INIT_LIST_HEAD(&transport_list); 730 packet = NULL; 731 732 /* 733 * 6.10 Bundling 734 * ... 735 * When bundling control chunks with DATA chunks, an 736 * endpoint MUST place control chunks first in the outbound 737 * SCTP packet. The transmitter MUST transmit DATA chunks 738 * within a SCTP packet in increasing order of TSN. 739 * ... 740 */ 741 742 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) { 743 /* RFC 5061, 5.3 744 * F1) This means that until such time as the ASCONF 745 * containing the add is acknowledged, the sender MUST 746 * NOT use the new IP address as a source for ANY SCTP 747 * packet except on carrying an ASCONF Chunk. 748 */ 749 if (asoc->src_out_of_asoc_ok && 750 chunk->chunk_hdr->type != SCTP_CID_ASCONF) 751 continue; 752 753 list_del_init(&chunk->list); 754 755 /* Pick the right transport to use. */ 756 new_transport = chunk->transport; 757 758 if (!new_transport) { 759 /* 760 * If we have a prior transport pointer, see if 761 * the destination address of the chunk 762 * matches the destination address of the 763 * current transport. If not a match, then 764 * try to look up the transport with a given 765 * destination address. We do this because 766 * after processing ASCONFs, we may have new 767 * transports created. 768 */ 769 if (transport && 770 sctp_cmp_addr_exact(&chunk->dest, 771 &transport->ipaddr)) 772 new_transport = transport; 773 else 774 new_transport = sctp_assoc_lookup_paddr(asoc, 775 &chunk->dest); 776 777 /* if we still don't have a new transport, then 778 * use the current active path. 779 */ 780 if (!new_transport) 781 new_transport = asoc->peer.active_path; 782 } else if ((new_transport->state == SCTP_INACTIVE) || 783 (new_transport->state == SCTP_UNCONFIRMED) || 784 (new_transport->state == SCTP_PF)) { 785 /* If the chunk is Heartbeat or Heartbeat Ack, 786 * send it to chunk->transport, even if it's 787 * inactive. 788 * 789 * 3.3.6 Heartbeat Acknowledgement: 790 * ... 791 * A HEARTBEAT ACK is always sent to the source IP 792 * address of the IP datagram containing the 793 * HEARTBEAT chunk to which this ack is responding. 794 * ... 795 * 796 * ASCONF_ACKs also must be sent to the source. 797 */ 798 if (chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT && 799 chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT_ACK && 800 chunk->chunk_hdr->type != SCTP_CID_ASCONF_ACK) 801 new_transport = asoc->peer.active_path; 802 } 803 804 /* Are we switching transports? 805 * Take care of transport locks. 806 */ 807 if (new_transport != transport) { 808 transport = new_transport; 809 if (list_empty(&transport->send_ready)) { 810 list_add_tail(&transport->send_ready, 811 &transport_list); 812 } 813 packet = &transport->packet; 814 sctp_packet_config(packet, vtag, 815 asoc->peer.ecn_capable); 816 } 817 818 switch (chunk->chunk_hdr->type) { 819 /* 820 * 6.10 Bundling 821 * ... 822 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN 823 * COMPLETE with any other chunks. [Send them immediately.] 824 */ 825 case SCTP_CID_INIT: 826 case SCTP_CID_INIT_ACK: 827 case SCTP_CID_SHUTDOWN_COMPLETE: 828 sctp_packet_init(&singleton, transport, sport, dport); 829 sctp_packet_config(&singleton, vtag, 0); 830 sctp_packet_append_chunk(&singleton, chunk); 831 error = sctp_packet_transmit(&singleton); 832 if (error < 0) 833 return error; 834 break; 835 836 case SCTP_CID_ABORT: 837 if (sctp_test_T_bit(chunk)) { 838 packet->vtag = asoc->c.my_vtag; 839 } 840 /* The following chunks are "response" chunks, i.e. 841 * they are generated in response to something we 842 * received. If we are sending these, then we can 843 * send only 1 packet containing these chunks. 844 */ 845 case SCTP_CID_HEARTBEAT_ACK: 846 case SCTP_CID_SHUTDOWN_ACK: 847 case SCTP_CID_COOKIE_ACK: 848 case SCTP_CID_COOKIE_ECHO: 849 case SCTP_CID_ERROR: 850 case SCTP_CID_ECN_CWR: 851 case SCTP_CID_ASCONF_ACK: 852 one_packet = 1; 853 /* Fall through */ 854 855 case SCTP_CID_SACK: 856 case SCTP_CID_HEARTBEAT: 857 case SCTP_CID_SHUTDOWN: 858 case SCTP_CID_ECN_ECNE: 859 case SCTP_CID_ASCONF: 860 case SCTP_CID_FWD_TSN: 861 status = sctp_packet_transmit_chunk(packet, chunk, 862 one_packet); 863 if (status != SCTP_XMIT_OK) { 864 /* put the chunk back */ 865 list_add(&chunk->list, &q->control_chunk_list); 866 } else { 867 asoc->stats.octrlchunks++; 868 /* PR-SCTP C5) If a FORWARD TSN is sent, the 869 * sender MUST assure that at least one T3-rtx 870 * timer is running. 871 */ 872 if (chunk->chunk_hdr->type == SCTP_CID_FWD_TSN) 873 sctp_transport_reset_timers(transport); 874 } 875 break; 876 877 default: 878 /* We built a chunk with an illegal type! */ 879 BUG(); 880 } 881 } 882 883 if (q->asoc->src_out_of_asoc_ok) 884 goto sctp_flush_out; 885 886 /* Is it OK to send data chunks? */ 887 switch (asoc->state) { 888 case SCTP_STATE_COOKIE_ECHOED: 889 /* Only allow bundling when this packet has a COOKIE-ECHO 890 * chunk. 891 */ 892 if (!packet || !packet->has_cookie_echo) 893 break; 894 895 /* fallthru */ 896 case SCTP_STATE_ESTABLISHED: 897 case SCTP_STATE_SHUTDOWN_PENDING: 898 case SCTP_STATE_SHUTDOWN_RECEIVED: 899 /* 900 * RFC 2960 6.1 Transmission of DATA Chunks 901 * 902 * C) When the time comes for the sender to transmit, 903 * before sending new DATA chunks, the sender MUST 904 * first transmit any outstanding DATA chunks which 905 * are marked for retransmission (limited by the 906 * current cwnd). 907 */ 908 if (!list_empty(&q->retransmit)) { 909 if (asoc->peer.retran_path->state == SCTP_UNCONFIRMED) 910 goto sctp_flush_out; 911 if (transport == asoc->peer.retran_path) 912 goto retran; 913 914 /* Switch transports & prepare the packet. */ 915 916 transport = asoc->peer.retran_path; 917 918 if (list_empty(&transport->send_ready)) { 919 list_add_tail(&transport->send_ready, 920 &transport_list); 921 } 922 923 packet = &transport->packet; 924 sctp_packet_config(packet, vtag, 925 asoc->peer.ecn_capable); 926 retran: 927 error = sctp_outq_flush_rtx(q, packet, 928 rtx_timeout, &start_timer); 929 930 if (start_timer) 931 sctp_transport_reset_timers(transport); 932 933 /* This can happen on COOKIE-ECHO resend. Only 934 * one chunk can get bundled with a COOKIE-ECHO. 935 */ 936 if (packet->has_cookie_echo) 937 goto sctp_flush_out; 938 939 /* Don't send new data if there is still data 940 * waiting to retransmit. 941 */ 942 if (!list_empty(&q->retransmit)) 943 goto sctp_flush_out; 944 } 945 946 /* Apply Max.Burst limitation to the current transport in 947 * case it will be used for new data. We are going to 948 * rest it before we return, but we want to apply the limit 949 * to the currently queued data. 950 */ 951 if (transport) 952 sctp_transport_burst_limited(transport); 953 954 /* Finally, transmit new packets. */ 955 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) { 956 /* RFC 2960 6.5 Every DATA chunk MUST carry a valid 957 * stream identifier. 958 */ 959 if (chunk->sinfo.sinfo_stream >= 960 asoc->c.sinit_num_ostreams) { 961 962 /* Mark as failed send. */ 963 sctp_chunk_fail(chunk, SCTP_ERROR_INV_STRM); 964 sctp_chunk_free(chunk); 965 continue; 966 } 967 968 /* Has this chunk expired? */ 969 if (sctp_chunk_abandoned(chunk)) { 970 sctp_chunk_fail(chunk, 0); 971 sctp_chunk_free(chunk); 972 continue; 973 } 974 975 /* If there is a specified transport, use it. 976 * Otherwise, we want to use the active path. 977 */ 978 new_transport = chunk->transport; 979 if (!new_transport || 980 ((new_transport->state == SCTP_INACTIVE) || 981 (new_transport->state == SCTP_UNCONFIRMED) || 982 (new_transport->state == SCTP_PF))) 983 new_transport = asoc->peer.active_path; 984 if (new_transport->state == SCTP_UNCONFIRMED) 985 continue; 986 987 /* Change packets if necessary. */ 988 if (new_transport != transport) { 989 transport = new_transport; 990 991 /* Schedule to have this transport's 992 * packet flushed. 993 */ 994 if (list_empty(&transport->send_ready)) { 995 list_add_tail(&transport->send_ready, 996 &transport_list); 997 } 998 999 packet = &transport->packet; 1000 sctp_packet_config(packet, vtag, 1001 asoc->peer.ecn_capable); 1002 /* We've switched transports, so apply the 1003 * Burst limit to the new transport. 1004 */ 1005 sctp_transport_burst_limited(transport); 1006 } 1007 1008 pr_debug("%s: outq:%p, chunk:%p[%s], tx-tsn:0x%x skb->head:%p " 1009 "skb->users:%d\n", 1010 __func__, q, chunk, chunk && chunk->chunk_hdr ? 1011 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) : 1012 "illegal chunk", ntohl(chunk->subh.data_hdr->tsn), 1013 chunk->skb ? chunk->skb->head : NULL, chunk->skb ? 1014 atomic_read(&chunk->skb->users) : -1); 1015 1016 /* Add the chunk to the packet. */ 1017 status = sctp_packet_transmit_chunk(packet, chunk, 0); 1018 1019 switch (status) { 1020 case SCTP_XMIT_PMTU_FULL: 1021 case SCTP_XMIT_RWND_FULL: 1022 case SCTP_XMIT_NAGLE_DELAY: 1023 /* We could not append this chunk, so put 1024 * the chunk back on the output queue. 1025 */ 1026 pr_debug("%s: could not transmit tsn:0x%x, status:%d\n", 1027 __func__, ntohl(chunk->subh.data_hdr->tsn), 1028 status); 1029 1030 sctp_outq_head_data(q, chunk); 1031 goto sctp_flush_out; 1032 break; 1033 1034 case SCTP_XMIT_OK: 1035 /* The sender is in the SHUTDOWN-PENDING state, 1036 * The sender MAY set the I-bit in the DATA 1037 * chunk header. 1038 */ 1039 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING) 1040 chunk->chunk_hdr->flags |= SCTP_DATA_SACK_IMM; 1041 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) 1042 asoc->stats.ouodchunks++; 1043 else 1044 asoc->stats.oodchunks++; 1045 1046 break; 1047 1048 default: 1049 BUG(); 1050 } 1051 1052 /* BUG: We assume that the sctp_packet_transmit() 1053 * call below will succeed all the time and add the 1054 * chunk to the transmitted list and restart the 1055 * timers. 1056 * It is possible that the call can fail under OOM 1057 * conditions. 1058 * 1059 * Is this really a problem? Won't this behave 1060 * like a lost TSN? 1061 */ 1062 list_add_tail(&chunk->transmitted_list, 1063 &transport->transmitted); 1064 1065 sctp_transport_reset_timers(transport); 1066 1067 q->empty = 0; 1068 1069 /* Only let one DATA chunk get bundled with a 1070 * COOKIE-ECHO chunk. 1071 */ 1072 if (packet->has_cookie_echo) 1073 goto sctp_flush_out; 1074 } 1075 break; 1076 1077 default: 1078 /* Do nothing. */ 1079 break; 1080 } 1081 1082 sctp_flush_out: 1083 1084 /* Before returning, examine all the transports touched in 1085 * this call. Right now, we bluntly force clear all the 1086 * transports. Things might change after we implement Nagle. 1087 * But such an examination is still required. 1088 * 1089 * --xguo 1090 */ 1091 while ((ltransport = sctp_list_dequeue(&transport_list)) != NULL) { 1092 struct sctp_transport *t = list_entry(ltransport, 1093 struct sctp_transport, 1094 send_ready); 1095 packet = &t->packet; 1096 if (!sctp_packet_empty(packet)) 1097 error = sctp_packet_transmit(packet); 1098 1099 /* Clear the burst limited state, if any */ 1100 sctp_transport_burst_reset(t); 1101 } 1102 1103 return error; 1104 } 1105 1106 /* Update unack_data based on the incoming SACK chunk */ 1107 static void sctp_sack_update_unack_data(struct sctp_association *assoc, 1108 struct sctp_sackhdr *sack) 1109 { 1110 sctp_sack_variable_t *frags; 1111 __u16 unack_data; 1112 int i; 1113 1114 unack_data = assoc->next_tsn - assoc->ctsn_ack_point - 1; 1115 1116 frags = sack->variable; 1117 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); i++) { 1118 unack_data -= ((ntohs(frags[i].gab.end) - 1119 ntohs(frags[i].gab.start) + 1)); 1120 } 1121 1122 assoc->unack_data = unack_data; 1123 } 1124 1125 /* This is where we REALLY process a SACK. 1126 * 1127 * Process the SACK against the outqueue. Mostly, this just frees 1128 * things off the transmitted queue. 1129 */ 1130 int sctp_outq_sack(struct sctp_outq *q, struct sctp_chunk *chunk) 1131 { 1132 struct sctp_association *asoc = q->asoc; 1133 struct sctp_sackhdr *sack = chunk->subh.sack_hdr; 1134 struct sctp_transport *transport; 1135 struct sctp_chunk *tchunk = NULL; 1136 struct list_head *lchunk, *transport_list, *temp; 1137 sctp_sack_variable_t *frags = sack->variable; 1138 __u32 sack_ctsn, ctsn, tsn; 1139 __u32 highest_tsn, highest_new_tsn; 1140 __u32 sack_a_rwnd; 1141 unsigned int outstanding; 1142 struct sctp_transport *primary = asoc->peer.primary_path; 1143 int count_of_newacks = 0; 1144 int gap_ack_blocks; 1145 u8 accum_moved = 0; 1146 1147 /* Grab the association's destination address list. */ 1148 transport_list = &asoc->peer.transport_addr_list; 1149 1150 sack_ctsn = ntohl(sack->cum_tsn_ack); 1151 gap_ack_blocks = ntohs(sack->num_gap_ack_blocks); 1152 asoc->stats.gapcnt += gap_ack_blocks; 1153 /* 1154 * SFR-CACC algorithm: 1155 * On receipt of a SACK the sender SHOULD execute the 1156 * following statements. 1157 * 1158 * 1) If the cumulative ack in the SACK passes next tsn_at_change 1159 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be 1160 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for 1161 * all destinations. 1162 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE 1163 * is set the receiver of the SACK MUST take the following actions: 1164 * 1165 * A) Initialize the cacc_saw_newack to 0 for all destination 1166 * addresses. 1167 * 1168 * Only bother if changeover_active is set. Otherwise, this is 1169 * totally suboptimal to do on every SACK. 1170 */ 1171 if (primary->cacc.changeover_active) { 1172 u8 clear_cycling = 0; 1173 1174 if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) { 1175 primary->cacc.changeover_active = 0; 1176 clear_cycling = 1; 1177 } 1178 1179 if (clear_cycling || gap_ack_blocks) { 1180 list_for_each_entry(transport, transport_list, 1181 transports) { 1182 if (clear_cycling) 1183 transport->cacc.cycling_changeover = 0; 1184 if (gap_ack_blocks) 1185 transport->cacc.cacc_saw_newack = 0; 1186 } 1187 } 1188 } 1189 1190 /* Get the highest TSN in the sack. */ 1191 highest_tsn = sack_ctsn; 1192 if (gap_ack_blocks) 1193 highest_tsn += ntohs(frags[gap_ack_blocks - 1].gab.end); 1194 1195 if (TSN_lt(asoc->highest_sacked, highest_tsn)) 1196 asoc->highest_sacked = highest_tsn; 1197 1198 highest_new_tsn = sack_ctsn; 1199 1200 /* Run through the retransmit queue. Credit bytes received 1201 * and free those chunks that we can. 1202 */ 1203 sctp_check_transmitted(q, &q->retransmit, NULL, NULL, sack, &highest_new_tsn); 1204 1205 /* Run through the transmitted queue. 1206 * Credit bytes received and free those chunks which we can. 1207 * 1208 * This is a MASSIVE candidate for optimization. 1209 */ 1210 list_for_each_entry(transport, transport_list, transports) { 1211 sctp_check_transmitted(q, &transport->transmitted, 1212 transport, &chunk->source, sack, 1213 &highest_new_tsn); 1214 /* 1215 * SFR-CACC algorithm: 1216 * C) Let count_of_newacks be the number of 1217 * destinations for which cacc_saw_newack is set. 1218 */ 1219 if (transport->cacc.cacc_saw_newack) 1220 count_of_newacks++; 1221 } 1222 1223 /* Move the Cumulative TSN Ack Point if appropriate. */ 1224 if (TSN_lt(asoc->ctsn_ack_point, sack_ctsn)) { 1225 asoc->ctsn_ack_point = sack_ctsn; 1226 accum_moved = 1; 1227 } 1228 1229 if (gap_ack_blocks) { 1230 1231 if (asoc->fast_recovery && accum_moved) 1232 highest_new_tsn = highest_tsn; 1233 1234 list_for_each_entry(transport, transport_list, transports) 1235 sctp_mark_missing(q, &transport->transmitted, transport, 1236 highest_new_tsn, count_of_newacks); 1237 } 1238 1239 /* Update unack_data field in the assoc. */ 1240 sctp_sack_update_unack_data(asoc, sack); 1241 1242 ctsn = asoc->ctsn_ack_point; 1243 1244 /* Throw away stuff rotting on the sack queue. */ 1245 list_for_each_safe(lchunk, temp, &q->sacked) { 1246 tchunk = list_entry(lchunk, struct sctp_chunk, 1247 transmitted_list); 1248 tsn = ntohl(tchunk->subh.data_hdr->tsn); 1249 if (TSN_lte(tsn, ctsn)) { 1250 list_del_init(&tchunk->transmitted_list); 1251 sctp_chunk_free(tchunk); 1252 } 1253 } 1254 1255 /* ii) Set rwnd equal to the newly received a_rwnd minus the 1256 * number of bytes still outstanding after processing the 1257 * Cumulative TSN Ack and the Gap Ack Blocks. 1258 */ 1259 1260 sack_a_rwnd = ntohl(sack->a_rwnd); 1261 outstanding = q->outstanding_bytes; 1262 1263 if (outstanding < sack_a_rwnd) 1264 sack_a_rwnd -= outstanding; 1265 else 1266 sack_a_rwnd = 0; 1267 1268 asoc->peer.rwnd = sack_a_rwnd; 1269 1270 sctp_generate_fwdtsn(q, sack_ctsn); 1271 1272 pr_debug("%s: sack cumulative tsn ack:0x%x\n", __func__, sack_ctsn); 1273 pr_debug("%s: cumulative tsn ack of assoc:%p is 0x%x, " 1274 "advertised peer ack point:0x%x\n", __func__, asoc, ctsn, 1275 asoc->adv_peer_ack_point); 1276 1277 /* See if all chunks are acked. 1278 * Make sure the empty queue handler will get run later. 1279 */ 1280 q->empty = (list_empty(&q->out_chunk_list) && 1281 list_empty(&q->retransmit)); 1282 if (!q->empty) 1283 goto finish; 1284 1285 list_for_each_entry(transport, transport_list, transports) { 1286 q->empty = q->empty && list_empty(&transport->transmitted); 1287 if (!q->empty) 1288 goto finish; 1289 } 1290 1291 pr_debug("%s: sack queue is empty\n", __func__); 1292 finish: 1293 return q->empty; 1294 } 1295 1296 /* Is the outqueue empty? */ 1297 int sctp_outq_is_empty(const struct sctp_outq *q) 1298 { 1299 return q->empty; 1300 } 1301 1302 /******************************************************************** 1303 * 2nd Level Abstractions 1304 ********************************************************************/ 1305 1306 /* Go through a transport's transmitted list or the association's retransmit 1307 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked. 1308 * The retransmit list will not have an associated transport. 1309 * 1310 * I added coherent debug information output. --xguo 1311 * 1312 * Instead of printing 'sacked' or 'kept' for each TSN on the 1313 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5. 1314 * KEPT TSN6-TSN7, etc. 1315 */ 1316 static void sctp_check_transmitted(struct sctp_outq *q, 1317 struct list_head *transmitted_queue, 1318 struct sctp_transport *transport, 1319 union sctp_addr *saddr, 1320 struct sctp_sackhdr *sack, 1321 __u32 *highest_new_tsn_in_sack) 1322 { 1323 struct list_head *lchunk; 1324 struct sctp_chunk *tchunk; 1325 struct list_head tlist; 1326 __u32 tsn; 1327 __u32 sack_ctsn; 1328 __u32 rtt; 1329 __u8 restart_timer = 0; 1330 int bytes_acked = 0; 1331 int migrate_bytes = 0; 1332 bool forward_progress = false; 1333 1334 sack_ctsn = ntohl(sack->cum_tsn_ack); 1335 1336 INIT_LIST_HEAD(&tlist); 1337 1338 /* The while loop will skip empty transmitted queues. */ 1339 while (NULL != (lchunk = sctp_list_dequeue(transmitted_queue))) { 1340 tchunk = list_entry(lchunk, struct sctp_chunk, 1341 transmitted_list); 1342 1343 if (sctp_chunk_abandoned(tchunk)) { 1344 /* Move the chunk to abandoned list. */ 1345 sctp_insert_list(&q->abandoned, lchunk); 1346 1347 /* If this chunk has not been acked, stop 1348 * considering it as 'outstanding'. 1349 */ 1350 if (!tchunk->tsn_gap_acked) { 1351 if (tchunk->transport) 1352 tchunk->transport->flight_size -= 1353 sctp_data_size(tchunk); 1354 q->outstanding_bytes -= sctp_data_size(tchunk); 1355 } 1356 continue; 1357 } 1358 1359 tsn = ntohl(tchunk->subh.data_hdr->tsn); 1360 if (sctp_acked(sack, tsn)) { 1361 /* If this queue is the retransmit queue, the 1362 * retransmit timer has already reclaimed 1363 * the outstanding bytes for this chunk, so only 1364 * count bytes associated with a transport. 1365 */ 1366 if (transport) { 1367 /* If this chunk is being used for RTT 1368 * measurement, calculate the RTT and update 1369 * the RTO using this value. 1370 * 1371 * 6.3.1 C5) Karn's algorithm: RTT measurements 1372 * MUST NOT be made using packets that were 1373 * retransmitted (and thus for which it is 1374 * ambiguous whether the reply was for the 1375 * first instance of the packet or a later 1376 * instance). 1377 */ 1378 if (!tchunk->tsn_gap_acked && 1379 !tchunk->resent && 1380 tchunk->rtt_in_progress) { 1381 tchunk->rtt_in_progress = 0; 1382 rtt = jiffies - tchunk->sent_at; 1383 sctp_transport_update_rto(transport, 1384 rtt); 1385 } 1386 } 1387 1388 /* If the chunk hasn't been marked as ACKED, 1389 * mark it and account bytes_acked if the 1390 * chunk had a valid transport (it will not 1391 * have a transport if ASCONF had deleted it 1392 * while DATA was outstanding). 1393 */ 1394 if (!tchunk->tsn_gap_acked) { 1395 tchunk->tsn_gap_acked = 1; 1396 if (TSN_lt(*highest_new_tsn_in_sack, tsn)) 1397 *highest_new_tsn_in_sack = tsn; 1398 bytes_acked += sctp_data_size(tchunk); 1399 if (!tchunk->transport) 1400 migrate_bytes += sctp_data_size(tchunk); 1401 forward_progress = true; 1402 } 1403 1404 if (TSN_lte(tsn, sack_ctsn)) { 1405 /* RFC 2960 6.3.2 Retransmission Timer Rules 1406 * 1407 * R3) Whenever a SACK is received 1408 * that acknowledges the DATA chunk 1409 * with the earliest outstanding TSN 1410 * for that address, restart T3-rtx 1411 * timer for that address with its 1412 * current RTO. 1413 */ 1414 restart_timer = 1; 1415 forward_progress = true; 1416 1417 if (!tchunk->tsn_gap_acked) { 1418 /* 1419 * SFR-CACC algorithm: 1420 * 2) If the SACK contains gap acks 1421 * and the flag CHANGEOVER_ACTIVE is 1422 * set the receiver of the SACK MUST 1423 * take the following action: 1424 * 1425 * B) For each TSN t being acked that 1426 * has not been acked in any SACK so 1427 * far, set cacc_saw_newack to 1 for 1428 * the destination that the TSN was 1429 * sent to. 1430 */ 1431 if (transport && 1432 sack->num_gap_ack_blocks && 1433 q->asoc->peer.primary_path->cacc. 1434 changeover_active) 1435 transport->cacc.cacc_saw_newack 1436 = 1; 1437 } 1438 1439 list_add_tail(&tchunk->transmitted_list, 1440 &q->sacked); 1441 } else { 1442 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2 1443 * M2) Each time a SACK arrives reporting 1444 * 'Stray DATA chunk(s)' record the highest TSN 1445 * reported as newly acknowledged, call this 1446 * value 'HighestTSNinSack'. A newly 1447 * acknowledged DATA chunk is one not 1448 * previously acknowledged in a SACK. 1449 * 1450 * When the SCTP sender of data receives a SACK 1451 * chunk that acknowledges, for the first time, 1452 * the receipt of a DATA chunk, all the still 1453 * unacknowledged DATA chunks whose TSN is 1454 * older than that newly acknowledged DATA 1455 * chunk, are qualified as 'Stray DATA chunks'. 1456 */ 1457 list_add_tail(lchunk, &tlist); 1458 } 1459 } else { 1460 if (tchunk->tsn_gap_acked) { 1461 pr_debug("%s: receiver reneged on data TSN:0x%x\n", 1462 __func__, tsn); 1463 1464 tchunk->tsn_gap_acked = 0; 1465 1466 if (tchunk->transport) 1467 bytes_acked -= sctp_data_size(tchunk); 1468 1469 /* RFC 2960 6.3.2 Retransmission Timer Rules 1470 * 1471 * R4) Whenever a SACK is received missing a 1472 * TSN that was previously acknowledged via a 1473 * Gap Ack Block, start T3-rtx for the 1474 * destination address to which the DATA 1475 * chunk was originally 1476 * transmitted if it is not already running. 1477 */ 1478 restart_timer = 1; 1479 } 1480 1481 list_add_tail(lchunk, &tlist); 1482 } 1483 } 1484 1485 if (transport) { 1486 if (bytes_acked) { 1487 struct sctp_association *asoc = transport->asoc; 1488 1489 /* We may have counted DATA that was migrated 1490 * to this transport due to DEL-IP operation. 1491 * Subtract those bytes, since the were never 1492 * send on this transport and shouldn't be 1493 * credited to this transport. 1494 */ 1495 bytes_acked -= migrate_bytes; 1496 1497 /* 8.2. When an outstanding TSN is acknowledged, 1498 * the endpoint shall clear the error counter of 1499 * the destination transport address to which the 1500 * DATA chunk was last sent. 1501 * The association's overall error counter is 1502 * also cleared. 1503 */ 1504 transport->error_count = 0; 1505 transport->asoc->overall_error_count = 0; 1506 forward_progress = true; 1507 1508 /* 1509 * While in SHUTDOWN PENDING, we may have started 1510 * the T5 shutdown guard timer after reaching the 1511 * retransmission limit. Stop that timer as soon 1512 * as the receiver acknowledged any data. 1513 */ 1514 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING && 1515 del_timer(&asoc->timers 1516 [SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD])) 1517 sctp_association_put(asoc); 1518 1519 /* Mark the destination transport address as 1520 * active if it is not so marked. 1521 */ 1522 if ((transport->state == SCTP_INACTIVE || 1523 transport->state == SCTP_UNCONFIRMED) && 1524 sctp_cmp_addr_exact(&transport->ipaddr, saddr)) { 1525 sctp_assoc_control_transport( 1526 transport->asoc, 1527 transport, 1528 SCTP_TRANSPORT_UP, 1529 SCTP_RECEIVED_SACK); 1530 } 1531 1532 sctp_transport_raise_cwnd(transport, sack_ctsn, 1533 bytes_acked); 1534 1535 transport->flight_size -= bytes_acked; 1536 if (transport->flight_size == 0) 1537 transport->partial_bytes_acked = 0; 1538 q->outstanding_bytes -= bytes_acked + migrate_bytes; 1539 } else { 1540 /* RFC 2960 6.1, sctpimpguide-06 2.15.2 1541 * When a sender is doing zero window probing, it 1542 * should not timeout the association if it continues 1543 * to receive new packets from the receiver. The 1544 * reason is that the receiver MAY keep its window 1545 * closed for an indefinite time. 1546 * A sender is doing zero window probing when the 1547 * receiver's advertised window is zero, and there is 1548 * only one data chunk in flight to the receiver. 1549 * 1550 * Allow the association to timeout while in SHUTDOWN 1551 * PENDING or SHUTDOWN RECEIVED in case the receiver 1552 * stays in zero window mode forever. 1553 */ 1554 if (!q->asoc->peer.rwnd && 1555 !list_empty(&tlist) && 1556 (sack_ctsn+2 == q->asoc->next_tsn) && 1557 q->asoc->state < SCTP_STATE_SHUTDOWN_PENDING) { 1558 pr_debug("%s: sack received for zero window " 1559 "probe:%u\n", __func__, sack_ctsn); 1560 1561 q->asoc->overall_error_count = 0; 1562 transport->error_count = 0; 1563 } 1564 } 1565 1566 /* RFC 2960 6.3.2 Retransmission Timer Rules 1567 * 1568 * R2) Whenever all outstanding data sent to an address have 1569 * been acknowledged, turn off the T3-rtx timer of that 1570 * address. 1571 */ 1572 if (!transport->flight_size) { 1573 if (del_timer(&transport->T3_rtx_timer)) 1574 sctp_transport_put(transport); 1575 } else if (restart_timer) { 1576 if (!mod_timer(&transport->T3_rtx_timer, 1577 jiffies + transport->rto)) 1578 sctp_transport_hold(transport); 1579 } 1580 1581 if (forward_progress) { 1582 if (transport->dst) 1583 dst_confirm(transport->dst); 1584 } 1585 } 1586 1587 list_splice(&tlist, transmitted_queue); 1588 } 1589 1590 /* Mark chunks as missing and consequently may get retransmitted. */ 1591 static void sctp_mark_missing(struct sctp_outq *q, 1592 struct list_head *transmitted_queue, 1593 struct sctp_transport *transport, 1594 __u32 highest_new_tsn_in_sack, 1595 int count_of_newacks) 1596 { 1597 struct sctp_chunk *chunk; 1598 __u32 tsn; 1599 char do_fast_retransmit = 0; 1600 struct sctp_association *asoc = q->asoc; 1601 struct sctp_transport *primary = asoc->peer.primary_path; 1602 1603 list_for_each_entry(chunk, transmitted_queue, transmitted_list) { 1604 1605 tsn = ntohl(chunk->subh.data_hdr->tsn); 1606 1607 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all 1608 * 'Unacknowledged TSN's', if the TSN number of an 1609 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack' 1610 * value, increment the 'TSN.Missing.Report' count on that 1611 * chunk if it has NOT been fast retransmitted or marked for 1612 * fast retransmit already. 1613 */ 1614 if (chunk->fast_retransmit == SCTP_CAN_FRTX && 1615 !chunk->tsn_gap_acked && 1616 TSN_lt(tsn, highest_new_tsn_in_sack)) { 1617 1618 /* SFR-CACC may require us to skip marking 1619 * this chunk as missing. 1620 */ 1621 if (!transport || !sctp_cacc_skip(primary, 1622 chunk->transport, 1623 count_of_newacks, tsn)) { 1624 chunk->tsn_missing_report++; 1625 1626 pr_debug("%s: tsn:0x%x missing counter:%d\n", 1627 __func__, tsn, chunk->tsn_missing_report); 1628 } 1629 } 1630 /* 1631 * M4) If any DATA chunk is found to have a 1632 * 'TSN.Missing.Report' 1633 * value larger than or equal to 3, mark that chunk for 1634 * retransmission and start the fast retransmit procedure. 1635 */ 1636 1637 if (chunk->tsn_missing_report >= 3) { 1638 chunk->fast_retransmit = SCTP_NEED_FRTX; 1639 do_fast_retransmit = 1; 1640 } 1641 } 1642 1643 if (transport) { 1644 if (do_fast_retransmit) 1645 sctp_retransmit(q, transport, SCTP_RTXR_FAST_RTX); 1646 1647 pr_debug("%s: transport:%p, cwnd:%d, ssthresh:%d, " 1648 "flight_size:%d, pba:%d\n", __func__, transport, 1649 transport->cwnd, transport->ssthresh, 1650 transport->flight_size, transport->partial_bytes_acked); 1651 } 1652 } 1653 1654 /* Is the given TSN acked by this packet? */ 1655 static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn) 1656 { 1657 int i; 1658 sctp_sack_variable_t *frags; 1659 __u16 gap; 1660 __u32 ctsn = ntohl(sack->cum_tsn_ack); 1661 1662 if (TSN_lte(tsn, ctsn)) 1663 goto pass; 1664 1665 /* 3.3.4 Selective Acknowledgement (SACK) (3): 1666 * 1667 * Gap Ack Blocks: 1668 * These fields contain the Gap Ack Blocks. They are repeated 1669 * for each Gap Ack Block up to the number of Gap Ack Blocks 1670 * defined in the Number of Gap Ack Blocks field. All DATA 1671 * chunks with TSNs greater than or equal to (Cumulative TSN 1672 * Ack + Gap Ack Block Start) and less than or equal to 1673 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack 1674 * Block are assumed to have been received correctly. 1675 */ 1676 1677 frags = sack->variable; 1678 gap = tsn - ctsn; 1679 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); ++i) { 1680 if (TSN_lte(ntohs(frags[i].gab.start), gap) && 1681 TSN_lte(gap, ntohs(frags[i].gab.end))) 1682 goto pass; 1683 } 1684 1685 return 0; 1686 pass: 1687 return 1; 1688 } 1689 1690 static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip *skiplist, 1691 int nskips, __be16 stream) 1692 { 1693 int i; 1694 1695 for (i = 0; i < nskips; i++) { 1696 if (skiplist[i].stream == stream) 1697 return i; 1698 } 1699 return i; 1700 } 1701 1702 /* Create and add a fwdtsn chunk to the outq's control queue if needed. */ 1703 static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 ctsn) 1704 { 1705 struct sctp_association *asoc = q->asoc; 1706 struct sctp_chunk *ftsn_chunk = NULL; 1707 struct sctp_fwdtsn_skip ftsn_skip_arr[10]; 1708 int nskips = 0; 1709 int skip_pos = 0; 1710 __u32 tsn; 1711 struct sctp_chunk *chunk; 1712 struct list_head *lchunk, *temp; 1713 1714 if (!asoc->peer.prsctp_capable) 1715 return; 1716 1717 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the 1718 * received SACK. 1719 * 1720 * If (Advanced.Peer.Ack.Point < SackCumAck), then update 1721 * Advanced.Peer.Ack.Point to be equal to SackCumAck. 1722 */ 1723 if (TSN_lt(asoc->adv_peer_ack_point, ctsn)) 1724 asoc->adv_peer_ack_point = ctsn; 1725 1726 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point" 1727 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as 1728 * the chunk next in the out-queue space is marked as "abandoned" as 1729 * shown in the following example: 1730 * 1731 * Assuming that a SACK arrived with the Cumulative TSN ACK 102 1732 * and the Advanced.Peer.Ack.Point is updated to this value: 1733 * 1734 * out-queue at the end of ==> out-queue after Adv.Ack.Point 1735 * normal SACK processing local advancement 1736 * ... ... 1737 * Adv.Ack.Pt-> 102 acked 102 acked 1738 * 103 abandoned 103 abandoned 1739 * 104 abandoned Adv.Ack.P-> 104 abandoned 1740 * 105 105 1741 * 106 acked 106 acked 1742 * ... ... 1743 * 1744 * In this example, the data sender successfully advanced the 1745 * "Advanced.Peer.Ack.Point" from 102 to 104 locally. 1746 */ 1747 list_for_each_safe(lchunk, temp, &q->abandoned) { 1748 chunk = list_entry(lchunk, struct sctp_chunk, 1749 transmitted_list); 1750 tsn = ntohl(chunk->subh.data_hdr->tsn); 1751 1752 /* Remove any chunks in the abandoned queue that are acked by 1753 * the ctsn. 1754 */ 1755 if (TSN_lte(tsn, ctsn)) { 1756 list_del_init(lchunk); 1757 sctp_chunk_free(chunk); 1758 } else { 1759 if (TSN_lte(tsn, asoc->adv_peer_ack_point+1)) { 1760 asoc->adv_peer_ack_point = tsn; 1761 if (chunk->chunk_hdr->flags & 1762 SCTP_DATA_UNORDERED) 1763 continue; 1764 skip_pos = sctp_get_skip_pos(&ftsn_skip_arr[0], 1765 nskips, 1766 chunk->subh.data_hdr->stream); 1767 ftsn_skip_arr[skip_pos].stream = 1768 chunk->subh.data_hdr->stream; 1769 ftsn_skip_arr[skip_pos].ssn = 1770 chunk->subh.data_hdr->ssn; 1771 if (skip_pos == nskips) 1772 nskips++; 1773 if (nskips == 10) 1774 break; 1775 } else 1776 break; 1777 } 1778 } 1779 1780 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point" 1781 * is greater than the Cumulative TSN ACK carried in the received 1782 * SACK, the data sender MUST send the data receiver a FORWARD TSN 1783 * chunk containing the latest value of the 1784 * "Advanced.Peer.Ack.Point". 1785 * 1786 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD 1787 * list each stream and sequence number in the forwarded TSN. This 1788 * information will enable the receiver to easily find any 1789 * stranded TSN's waiting on stream reorder queues. Each stream 1790 * SHOULD only be reported once; this means that if multiple 1791 * abandoned messages occur in the same stream then only the 1792 * highest abandoned stream sequence number is reported. If the 1793 * total size of the FORWARD TSN does NOT fit in a single MTU then 1794 * the sender of the FORWARD TSN SHOULD lower the 1795 * Advanced.Peer.Ack.Point to the last TSN that will fit in a 1796 * single MTU. 1797 */ 1798 if (asoc->adv_peer_ack_point > ctsn) 1799 ftsn_chunk = sctp_make_fwdtsn(asoc, asoc->adv_peer_ack_point, 1800 nskips, &ftsn_skip_arr[0]); 1801 1802 if (ftsn_chunk) { 1803 list_add_tail(&ftsn_chunk->list, &q->control_chunk_list); 1804 SCTP_INC_STATS(sock_net(asoc->base.sk), SCTP_MIB_OUTCTRLCHUNKS); 1805 } 1806 } 1807