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