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