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, write to 26 * the Free Software Foundation, 59 Temple Place - Suite 330, 27 * Boston, MA 02111-1307, USA. 28 * 29 * Please send any bug reports or fixes you make to the 30 * email address(es): 31 * lksctp developers <lksctp-developers@lists.sourceforge.net> 32 * 33 * Or submit a bug report through the following website: 34 * http://www.sf.net/projects/lksctp 35 * 36 * Written or modified by: 37 * La Monte H.P. Yarroll <piggy@acm.org> 38 * Karl Knutson <karl@athena.chicago.il.us> 39 * Perry Melange <pmelange@null.cc.uic.edu> 40 * Xingang Guo <xingang.guo@intel.com> 41 * Hui Huang <hui.huang@nokia.com> 42 * Sridhar Samudrala <sri@us.ibm.com> 43 * Jon Grimm <jgrimm@us.ibm.com> 44 * 45 * Any bugs reported given to us we will try to fix... any fixes shared will 46 * be incorporated into the next SCTP release. 47 */ 48 49#include <linux/types.h> 50#include <linux/list.h> /* For struct list_head */ 51#include <linux/socket.h> 52#include <linux/ip.h> 53#include <linux/slab.h> 54#include <net/sock.h> /* For skb_set_owner_w */ 55 56#include <net/sctp/sctp.h> 57#include <net/sctp/sm.h> 58 59/* Declare internal functions here. */ 60static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn); 61static void sctp_check_transmitted(struct sctp_outq *q, 62 struct list_head *transmitted_queue, 63 struct sctp_transport *transport, 64 struct sctp_sackhdr *sack, 65 __u32 *highest_new_tsn); 66 67static void sctp_mark_missing(struct sctp_outq *q, 68 struct list_head *transmitted_queue, 69 struct sctp_transport *transport, 70 __u32 highest_new_tsn, 71 int count_of_newacks); 72 73static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 sack_ctsn); 74 75static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout); 76 77/* Add data to the front of the queue. */ 78static inline void sctp_outq_head_data(struct sctp_outq *q, 79 struct sctp_chunk *ch) 80{ 81 list_add(&ch->list, &q->out_chunk_list); 82 q->out_qlen += ch->skb->len; 83} 84 85/* Take data from the front of the queue. */ 86static inline struct sctp_chunk *sctp_outq_dequeue_data(struct sctp_outq *q) 87{ 88 struct sctp_chunk *ch = NULL; 89 90 if (!list_empty(&q->out_chunk_list)) { 91 struct list_head *entry = q->out_chunk_list.next; 92 93 ch = list_entry(entry, struct sctp_chunk, list); 94 list_del_init(entry); 95 q->out_qlen -= ch->skb->len; 96 } 97 return ch; 98} 99/* Add data chunk to the end of the queue. */ 100static inline void sctp_outq_tail_data(struct sctp_outq *q, 101 struct sctp_chunk *ch) 102{ 103 list_add_tail(&ch->list, &q->out_chunk_list); 104 q->out_qlen += ch->skb->len; 105} 106 107/* 108 * SFR-CACC algorithm: 109 * D) If count_of_newacks is greater than or equal to 2 110 * and t was not sent to the current primary then the 111 * sender MUST NOT increment missing report count for t. 112 */ 113static inline int sctp_cacc_skip_3_1_d(struct sctp_transport *primary, 114 struct sctp_transport *transport, 115 int count_of_newacks) 116{ 117 if (count_of_newacks >=2 && transport != primary) 118 return 1; 119 return 0; 120} 121 122/* 123 * SFR-CACC algorithm: 124 * F) If count_of_newacks is less than 2, let d be the 125 * destination to which t was sent. If cacc_saw_newack 126 * is 0 for destination d, then the sender MUST NOT 127 * increment missing report count for t. 128 */ 129static inline int sctp_cacc_skip_3_1_f(struct sctp_transport *transport, 130 int count_of_newacks) 131{ 132 if (count_of_newacks < 2 && !transport->cacc.cacc_saw_newack) 133 return 1; 134 return 0; 135} 136 137/* 138 * SFR-CACC algorithm: 139 * 3.1) If CYCLING_CHANGEOVER is 0, the sender SHOULD 140 * execute steps C, D, F. 141 * 142 * C has been implemented in sctp_outq_sack 143 */ 144static inline int sctp_cacc_skip_3_1(struct sctp_transport *primary, 145 struct sctp_transport *transport, 146 int count_of_newacks) 147{ 148 if (!primary->cacc.cycling_changeover) { 149 if (sctp_cacc_skip_3_1_d(primary, transport, count_of_newacks)) 150 return 1; 151 if (sctp_cacc_skip_3_1_f(transport, count_of_newacks)) 152 return 1; 153 return 0; 154 } 155 return 0; 156} 157 158/* 159 * SFR-CACC algorithm: 160 * 3.2) Else if CYCLING_CHANGEOVER is 1, and t is less 161 * than next_tsn_at_change of the current primary, then 162 * the sender MUST NOT increment missing report count 163 * for t. 164 */ 165static inline int sctp_cacc_skip_3_2(struct sctp_transport *primary, __u32 tsn) 166{ 167 if (primary->cacc.cycling_changeover && 168 TSN_lt(tsn, primary->cacc.next_tsn_at_change)) 169 return 1; 170 return 0; 171} 172 173/* 174 * SFR-CACC algorithm: 175 * 3) If the missing report count for TSN t is to be 176 * incremented according to [RFC2960] and 177 * [SCTP_STEWART-2002], and CHANGEOVER_ACTIVE is set, 178 * then the sender MUST futher execute steps 3.1 and 179 * 3.2 to determine if the missing report count for 180 * TSN t SHOULD NOT be incremented. 181 * 182 * 3.3) If 3.1 and 3.2 do not dictate that the missing 183 * report count for t should not be incremented, then 184 * the sender SOULD increment missing report count for 185 * t (according to [RFC2960] and [SCTP_STEWART_2002]). 186 */ 187static inline int sctp_cacc_skip(struct sctp_transport *primary, 188 struct sctp_transport *transport, 189 int count_of_newacks, 190 __u32 tsn) 191{ 192 if (primary->cacc.changeover_active && 193 (sctp_cacc_skip_3_1(primary, transport, count_of_newacks) || 194 sctp_cacc_skip_3_2(primary, tsn))) 195 return 1; 196 return 0; 197} 198 199/* Initialize an existing sctp_outq. This does the boring stuff. 200 * You still need to define handlers if you really want to DO 201 * something with this structure... 202 */ 203void sctp_outq_init(struct sctp_association *asoc, struct sctp_outq *q) 204{ 205 q->asoc = asoc; 206 INIT_LIST_HEAD(&q->out_chunk_list); 207 INIT_LIST_HEAD(&q->control_chunk_list); 208 INIT_LIST_HEAD(&q->retransmit); 209 INIT_LIST_HEAD(&q->sacked); 210 INIT_LIST_HEAD(&q->abandoned); 211 212 q->fast_rtx = 0; 213 q->outstanding_bytes = 0; 214 q->empty = 1; 215 q->cork = 0; 216 217 q->malloced = 0; 218 q->out_qlen = 0; 219} 220 221/* Free the outqueue structure and any related pending chunks. 222 */ 223void sctp_outq_teardown(struct sctp_outq *q) 224{ 225 struct sctp_transport *transport; 226 struct list_head *lchunk, *temp; 227 struct sctp_chunk *chunk, *tmp; 228 229 /* Throw away unacknowledged chunks. */ 230 list_for_each_entry(transport, &q->asoc->peer.transport_addr_list, 231 transports) { 232 while ((lchunk = sctp_list_dequeue(&transport->transmitted)) != NULL) { 233 chunk = list_entry(lchunk, struct sctp_chunk, 234 transmitted_list); 235 /* Mark as part of a failed message. */ 236 sctp_chunk_fail(chunk, q->error); 237 sctp_chunk_free(chunk); 238 } 239 } 240 241 /* Throw away chunks that have been gap ACKed. */ 242 list_for_each_safe(lchunk, temp, &q->sacked) { 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 in the retransmit queue. */ 251 list_for_each_safe(lchunk, temp, &q->retransmit) { 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 chunks that are in the abandoned queue. */ 260 list_for_each_safe(lchunk, temp, &q->abandoned) { 261 list_del_init(lchunk); 262 chunk = list_entry(lchunk, struct sctp_chunk, 263 transmitted_list); 264 sctp_chunk_fail(chunk, q->error); 265 sctp_chunk_free(chunk); 266 } 267 268 /* Throw away any leftover data chunks. */ 269 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) { 270 271 /* Mark as send failure. */ 272 sctp_chunk_fail(chunk, q->error); 273 sctp_chunk_free(chunk); 274 } 275 276 q->error = 0; 277 278 /* Throw away any leftover control chunks. */ 279 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) { 280 list_del_init(&chunk->list); 281 sctp_chunk_free(chunk); 282 } 283} 284 285/* Free the outqueue structure and any related pending chunks. */ 286void sctp_outq_free(struct sctp_outq *q) 287{ 288 /* Throw away leftover chunks. */ 289 sctp_outq_teardown(q); 290 291 /* If we were kmalloc()'d, free the memory. */ 292 if (q->malloced) 293 kfree(q); 294} 295 296/* Put a new chunk in an sctp_outq. */ 297int sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk) 298{ 299 int error = 0; 300 301 SCTP_DEBUG_PRINTK("sctp_outq_tail(%p, %p[%s])\n", 302 q, chunk, chunk && chunk->chunk_hdr ? 303 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) 304 : "Illegal Chunk"); 305 306 /* If it is data, queue it up, otherwise, send it 307 * immediately. 308 */ 309 if (sctp_chunk_is_data(chunk)) { 310 /* Is it OK to queue data chunks? */ 311 /* From 9. Termination of Association 312 * 313 * When either endpoint performs a shutdown, the 314 * association on each peer will stop accepting new 315 * data from its user and only deliver data in queue 316 * at the time of sending or receiving the SHUTDOWN 317 * chunk. 318 */ 319 switch (q->asoc->state) { 320 case SCTP_STATE_EMPTY: 321 case SCTP_STATE_CLOSED: 322 case SCTP_STATE_SHUTDOWN_PENDING: 323 case SCTP_STATE_SHUTDOWN_SENT: 324 case SCTP_STATE_SHUTDOWN_RECEIVED: 325 case SCTP_STATE_SHUTDOWN_ACK_SENT: 326 /* Cannot send after transport endpoint shutdown */ 327 error = -ESHUTDOWN; 328 break; 329 330 default: 331 SCTP_DEBUG_PRINTK("outqueueing (%p, %p[%s])\n", 332 q, chunk, chunk && chunk->chunk_hdr ? 333 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) 334 : "Illegal Chunk"); 335 336 sctp_outq_tail_data(q, chunk); 337 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) 338 SCTP_INC_STATS(SCTP_MIB_OUTUNORDERCHUNKS); 339 else 340 SCTP_INC_STATS(SCTP_MIB_OUTORDERCHUNKS); 341 q->empty = 0; 342 break; 343 } 344 } else { 345 list_add_tail(&chunk->list, &q->control_chunk_list); 346 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 347 } 348 349 if (error < 0) 350 return error; 351 352 if (!q->cork) 353 error = sctp_outq_flush(q, 0); 354 355 return error; 356} 357 358/* Insert a chunk into the sorted list based on the TSNs. The retransmit list 359 * and the abandoned list are in ascending order. 360 */ 361static void sctp_insert_list(struct list_head *head, struct list_head *new) 362{ 363 struct list_head *pos; 364 struct sctp_chunk *nchunk, *lchunk; 365 __u32 ntsn, ltsn; 366 int done = 0; 367 368 nchunk = list_entry(new, struct sctp_chunk, transmitted_list); 369 ntsn = ntohl(nchunk->subh.data_hdr->tsn); 370 371 list_for_each(pos, head) { 372 lchunk = list_entry(pos, struct sctp_chunk, transmitted_list); 373 ltsn = ntohl(lchunk->subh.data_hdr->tsn); 374 if (TSN_lt(ntsn, ltsn)) { 375 list_add(new, pos->prev); 376 done = 1; 377 break; 378 } 379 } 380 if (!done) 381 list_add_tail(new, head); 382} 383 384/* Mark all the eligible packets on a transport for retransmission. */ 385void sctp_retransmit_mark(struct sctp_outq *q, 386 struct sctp_transport *transport, 387 __u8 reason) 388{ 389 struct list_head *lchunk, *ltemp; 390 struct sctp_chunk *chunk; 391 392 /* Walk through the specified transmitted queue. */ 393 list_for_each_safe(lchunk, ltemp, &transport->transmitted) { 394 chunk = list_entry(lchunk, struct sctp_chunk, 395 transmitted_list); 396 397 /* If the chunk is abandoned, move it to abandoned list. */ 398 if (sctp_chunk_abandoned(chunk)) { 399 list_del_init(lchunk); 400 sctp_insert_list(&q->abandoned, lchunk); 401 402 /* If this chunk has not been previousely acked, 403 * stop considering it 'outstanding'. Our peer 404 * will most likely never see it since it will 405 * not be retransmitted 406 */ 407 if (!chunk->tsn_gap_acked) { 408 if (chunk->transport) 409 chunk->transport->flight_size -= 410 sctp_data_size(chunk); 411 q->outstanding_bytes -= sctp_data_size(chunk); 412 q->asoc->peer.rwnd += (sctp_data_size(chunk) + 413 sizeof(struct sk_buff)); 414 } 415 continue; 416 } 417 418 /* If we are doing retransmission due to a timeout or pmtu 419 * discovery, only the chunks that are not yet acked should 420 * be added to the retransmit queue. 421 */ 422 if ((reason == SCTP_RTXR_FAST_RTX && 423 (chunk->fast_retransmit == SCTP_NEED_FRTX)) || 424 (reason != SCTP_RTXR_FAST_RTX && !chunk->tsn_gap_acked)) { 425 /* RFC 2960 6.2.1 Processing a Received SACK 426 * 427 * C) Any time a DATA chunk is marked for 428 * retransmission (via either T3-rtx timer expiration 429 * (Section 6.3.3) or via fast retransmit 430 * (Section 7.2.4)), add the data size of those 431 * chunks to the rwnd. 432 */ 433 q->asoc->peer.rwnd += (sctp_data_size(chunk) + 434 sizeof(struct sk_buff)); 435 q->outstanding_bytes -= sctp_data_size(chunk); 436 if (chunk->transport) 437 transport->flight_size -= sctp_data_size(chunk); 438 439 /* sctpimpguide-05 Section 2.8.2 440 * M5) If a T3-rtx timer expires, the 441 * 'TSN.Missing.Report' of all affected TSNs is set 442 * to 0. 443 */ 444 chunk->tsn_missing_report = 0; 445 446 /* If a chunk that is being used for RTT measurement 447 * has to be retransmitted, we cannot use this chunk 448 * anymore for RTT measurements. Reset rto_pending so 449 * that a new RTT measurement is started when a new 450 * data chunk is sent. 451 */ 452 if (chunk->rtt_in_progress) { 453 chunk->rtt_in_progress = 0; 454 transport->rto_pending = 0; 455 } 456 457 /* Move the chunk to the retransmit queue. The chunks 458 * on the retransmit queue are always kept in order. 459 */ 460 list_del_init(lchunk); 461 sctp_insert_list(&q->retransmit, lchunk); 462 } 463 } 464 465 SCTP_DEBUG_PRINTK("%s: transport: %p, reason: %d, " 466 "cwnd: %d, ssthresh: %d, flight_size: %d, " 467 "pba: %d\n", __func__, 468 transport, reason, 469 transport->cwnd, transport->ssthresh, 470 transport->flight_size, 471 transport->partial_bytes_acked); 472 473} 474 475/* Mark all the eligible packets on a transport for retransmission and force 476 * one packet out. 477 */ 478void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport, 479 sctp_retransmit_reason_t reason) 480{ 481 int error = 0; 482 483 switch(reason) { 484 case SCTP_RTXR_T3_RTX: 485 SCTP_INC_STATS(SCTP_MIB_T3_RETRANSMITS); 486 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_T3_RTX); 487 /* Update the retran path if the T3-rtx timer has expired for 488 * the current retran path. 489 */ 490 if (transport == transport->asoc->peer.retran_path) 491 sctp_assoc_update_retran_path(transport->asoc); 492 transport->asoc->rtx_data_chunks += 493 transport->asoc->unack_data; 494 break; 495 case SCTP_RTXR_FAST_RTX: 496 SCTP_INC_STATS(SCTP_MIB_FAST_RETRANSMITS); 497 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_FAST_RTX); 498 q->fast_rtx = 1; 499 break; 500 case SCTP_RTXR_PMTUD: 501 SCTP_INC_STATS(SCTP_MIB_PMTUD_RETRANSMITS); 502 break; 503 case SCTP_RTXR_T1_RTX: 504 SCTP_INC_STATS(SCTP_MIB_T1_RETRANSMITS); 505 transport->asoc->init_retries++; 506 break; 507 default: 508 BUG(); 509 } 510 511 sctp_retransmit_mark(q, transport, reason); 512 513 /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination, 514 * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by 515 * following the procedures outlined in C1 - C5. 516 */ 517 if (reason == SCTP_RTXR_T3_RTX) 518 sctp_generate_fwdtsn(q, q->asoc->ctsn_ack_point); 519 520 /* Flush the queues only on timeout, since fast_rtx is only 521 * triggered during sack processing and the queue 522 * will be flushed at the end. 523 */ 524 if (reason != SCTP_RTXR_FAST_RTX) 525 error = sctp_outq_flush(q, /* rtx_timeout */ 1); 526 527 if (error) 528 q->asoc->base.sk->sk_err = -error; 529} 530 531/* 532 * Transmit DATA chunks on the retransmit queue. Upon return from 533 * sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which 534 * need to be transmitted by the caller. 535 * We assume that pkt->transport has already been set. 536 * 537 * The return value is a normal kernel error return value. 538 */ 539static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt, 540 int rtx_timeout, int *start_timer) 541{ 542 struct list_head *lqueue; 543 struct sctp_transport *transport = pkt->transport; 544 sctp_xmit_t status; 545 struct sctp_chunk *chunk, *chunk1; 546 struct sctp_association *asoc; 547 int fast_rtx; 548 int error = 0; 549 int timer = 0; 550 int done = 0; 551 552 asoc = q->asoc; 553 lqueue = &q->retransmit; 554 fast_rtx = q->fast_rtx; 555 556 /* This loop handles time-out retransmissions, fast retransmissions, 557 * and retransmissions due to opening of whindow. 558 * 559 * RFC 2960 6.3.3 Handle T3-rtx Expiration 560 * 561 * E3) Determine how many of the earliest (i.e., lowest TSN) 562 * outstanding DATA chunks for the address for which the 563 * T3-rtx has expired will fit into a single packet, subject 564 * to the MTU constraint for the path corresponding to the 565 * destination transport address to which the retransmission 566 * is being sent (this may be different from the address for 567 * which the timer expires [see Section 6.4]). Call this value 568 * K. Bundle and retransmit those K DATA chunks in a single 569 * packet to the destination endpoint. 570 * 571 * [Just to be painfully clear, if we are retransmitting 572 * because a timeout just happened, we should send only ONE 573 * packet of retransmitted data.] 574 * 575 * For fast retransmissions we also send only ONE packet. However, 576 * if we are just flushing the queue due to open window, we'll 577 * try to send as much as possible. 578 */ 579 list_for_each_entry_safe(chunk, chunk1, lqueue, transmitted_list) { 580 581 /* Make sure that Gap Acked TSNs are not retransmitted. A 582 * simple approach is just to move such TSNs out of the 583 * way and into a 'transmitted' queue and skip to the 584 * next chunk. 585 */ 586 if (chunk->tsn_gap_acked) { 587 list_del(&chunk->transmitted_list); 588 list_add_tail(&chunk->transmitted_list, 589 &transport->transmitted); 590 continue; 591 } 592 593 /* If we are doing fast retransmit, ignore non-fast_rtransmit 594 * chunks 595 */ 596 if (fast_rtx && !chunk->fast_retransmit) 597 continue; 598 599redo: 600 /* Attempt to append this chunk to the packet. */ 601 status = sctp_packet_append_chunk(pkt, chunk); 602 603 switch (status) { 604 case SCTP_XMIT_PMTU_FULL: 605 if (!pkt->has_data && !pkt->has_cookie_echo) { 606 /* If this packet did not contain DATA then 607 * retransmission did not happen, so do it 608 * again. We'll ignore the error here since 609 * control chunks are already freed so there 610 * is nothing we can do. 611 */ 612 sctp_packet_transmit(pkt); 613 goto redo; 614 } 615 616 /* Send this packet. */ 617 error = sctp_packet_transmit(pkt); 618 619 /* If we are retransmitting, we should only 620 * send a single packet. 621 */ 622 if (rtx_timeout || fast_rtx) 623 done = 1; 624 625 /* Bundle next chunk in the next round. */ 626 break; 627 628 case SCTP_XMIT_RWND_FULL: 629 /* Send this packet. */ 630 error = sctp_packet_transmit(pkt); 631 632 /* Stop sending DATA as there is no more room 633 * at the receiver. 634 */ 635 done = 1; 636 break; 637 638 case SCTP_XMIT_NAGLE_DELAY: 639 /* Send this packet. */ 640 error = sctp_packet_transmit(pkt); 641 642 /* Stop sending DATA because of nagle delay. */ 643 done = 1; 644 break; 645 646 default: 647 /* The append was successful, so add this chunk to 648 * the transmitted list. 649 */ 650 list_del(&chunk->transmitted_list); 651 list_add_tail(&chunk->transmitted_list, 652 &transport->transmitted); 653 654 /* Mark the chunk as ineligible for fast retransmit 655 * after it is retransmitted. 656 */ 657 if (chunk->fast_retransmit == SCTP_NEED_FRTX) 658 chunk->fast_retransmit = SCTP_DONT_FRTX; 659 660 q->empty = 0; 661 break; 662 } 663 664 /* Set the timer if there were no errors */ 665 if (!error && !timer) 666 timer = 1; 667 668 if (done) 669 break; 670 } 671 672 /* If we are here due to a retransmit timeout or a fast 673 * retransmit and if there are any chunks left in the retransmit 674 * queue that could not fit in the PMTU sized packet, they need 675 * to be marked as ineligible for a subsequent fast retransmit. 676 */ 677 if (rtx_timeout || fast_rtx) { 678 list_for_each_entry(chunk1, lqueue, transmitted_list) { 679 if (chunk1->fast_retransmit == SCTP_NEED_FRTX) 680 chunk1->fast_retransmit = SCTP_DONT_FRTX; 681 } 682 } 683 684 *start_timer = timer; 685 686 /* Clear fast retransmit hint */ 687 if (fast_rtx) 688 q->fast_rtx = 0; 689 690 return error; 691} 692 693/* Cork the outqueue so queued chunks are really queued. */ 694int sctp_outq_uncork(struct sctp_outq *q) 695{ 696 int error = 0; 697 if (q->cork) 698 q->cork = 0; 699 error = sctp_outq_flush(q, 0); 700 return error; 701} 702 703 704/* 705 * Try to flush an outqueue. 706 * 707 * Description: Send everything in q which we legally can, subject to 708 * congestion limitations. 709 * * Note: This function can be called from multiple contexts so appropriate 710 * locking concerns must be made. Today we use the sock lock to protect 711 * this function. 712 */ 713static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout) 714{ 715 struct sctp_packet *packet; 716 struct sctp_packet singleton; 717 struct sctp_association *asoc = q->asoc; 718 __u16 sport = asoc->base.bind_addr.port; 719 __u16 dport = asoc->peer.port; 720 __u32 vtag = asoc->peer.i.init_tag; 721 struct sctp_transport *transport = NULL; 722 struct sctp_transport *new_transport; 723 struct sctp_chunk *chunk, *tmp; 724 sctp_xmit_t status; 725 int error = 0; 726 int start_timer = 0; 727 int one_packet = 0; 728 729 /* These transports have chunks to send. */ 730 struct list_head transport_list; 731 struct list_head *ltransport; 732 733 INIT_LIST_HEAD(&transport_list); 734 packet = NULL; 735 736 /* 737 * 6.10 Bundling 738 * ... 739 * When bundling control chunks with DATA chunks, an 740 * endpoint MUST place control chunks first in the outbound 741 * SCTP packet. The transmitter MUST transmit DATA chunks 742 * within a SCTP packet in increasing order of TSN. 743 * ... 744 */ 745 746 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) { 747 list_del_init(&chunk->list); 748 749 /* Pick the right transport to use. */ 750 new_transport = chunk->transport; 751 752 if (!new_transport) { 753 /* 754 * If we have a prior transport pointer, see if 755 * the destination address of the chunk 756 * matches the destination address of the 757 * current transport. If not a match, then 758 * try to look up the transport with a given 759 * destination address. We do this because 760 * after processing ASCONFs, we may have new 761 * transports created. 762 */ 763 if (transport && 764 sctp_cmp_addr_exact(&chunk->dest, 765 &transport->ipaddr)) 766 new_transport = transport; 767 else 768 new_transport = sctp_assoc_lookup_paddr(asoc, 769 &chunk->dest); 770 771 /* if we still don't have a new transport, then 772 * use the current active path. 773 */ 774 if (!new_transport) 775 new_transport = asoc->peer.active_path; 776 } else if ((new_transport->state == SCTP_INACTIVE) || 777 (new_transport->state == SCTP_UNCONFIRMED)) { 778 /* If the chunk is Heartbeat or Heartbeat Ack, 779 * send it to chunk->transport, even if it's 780 * inactive. 781 * 782 * 3.3.6 Heartbeat Acknowledgement: 783 * ... 784 * A HEARTBEAT ACK is always sent to the source IP 785 * address of the IP datagram containing the 786 * HEARTBEAT chunk to which this ack is responding. 787 * ... 788 * 789 * ASCONF_ACKs also must be sent to the source. 790 */ 791 if (chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT && 792 chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT_ACK && 793 chunk->chunk_hdr->type != SCTP_CID_ASCONF_ACK) 794 new_transport = asoc->peer.active_path; 795 } 796 797 /* Are we switching transports? 798 * Take care of transport locks. 799 */ 800 if (new_transport != transport) { 801 transport = new_transport; 802 if (list_empty(&transport->send_ready)) { 803 list_add_tail(&transport->send_ready, 804 &transport_list); 805 } 806 packet = &transport->packet; 807 sctp_packet_config(packet, vtag, 808 asoc->peer.ecn_capable); 809 } 810 811 switch (chunk->chunk_hdr->type) { 812 /* 813 * 6.10 Bundling 814 * ... 815 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN 816 * COMPLETE with any other chunks. [Send them immediately.] 817 */ 818 case SCTP_CID_INIT: 819 case SCTP_CID_INIT_ACK: 820 case SCTP_CID_SHUTDOWN_COMPLETE: 821 sctp_packet_init(&singleton, transport, sport, dport); 822 sctp_packet_config(&singleton, vtag, 0); 823 sctp_packet_append_chunk(&singleton, chunk); 824 error = sctp_packet_transmit(&singleton); 825 if (error < 0) 826 return error; 827 break; 828 829 case SCTP_CID_ABORT: 830 if (sctp_test_T_bit(chunk)) { 831 packet->vtag = asoc->c.my_vtag; 832 } 833 /* The following chunks are "response" chunks, i.e. 834 * they are generated in response to something we 835 * received. If we are sending these, then we can 836 * send only 1 packet containing these chunks. 837 */ 838 case SCTP_CID_HEARTBEAT_ACK: 839 case SCTP_CID_SHUTDOWN_ACK: 840 case SCTP_CID_COOKIE_ACK: 841 case SCTP_CID_COOKIE_ECHO: 842 case SCTP_CID_ERROR: 843 case SCTP_CID_ECN_CWR: 844 case SCTP_CID_ASCONF_ACK: 845 one_packet = 1; 846 /* Fall throught */ 847 848 case SCTP_CID_SACK: 849 case SCTP_CID_HEARTBEAT: 850 case SCTP_CID_SHUTDOWN: 851 case SCTP_CID_ECN_ECNE: 852 case SCTP_CID_ASCONF: 853 case SCTP_CID_FWD_TSN: 854 status = sctp_packet_transmit_chunk(packet, chunk, 855 one_packet); 856 if (status != SCTP_XMIT_OK) { 857 /* put the chunk back */ 858 list_add(&chunk->list, &q->control_chunk_list); 859 } else if (chunk->chunk_hdr->type == SCTP_CID_FWD_TSN) { 860 /* PR-SCTP C5) If a FORWARD TSN is sent, the 861 * sender MUST assure that at least one T3-rtx 862 * timer is running. 863 */ 864 sctp_transport_reset_timers(transport); 865 } 866 break; 867 868 default: 869 /* We built a chunk with an illegal type! */ 870 BUG(); 871 } 872 } 873 874 /* Is it OK to send data chunks? */ 875 switch (asoc->state) { 876 case SCTP_STATE_COOKIE_ECHOED: 877 /* Only allow bundling when this packet has a COOKIE-ECHO 878 * chunk. 879 */ 880 if (!packet || !packet->has_cookie_echo) 881 break; 882 883 /* fallthru */ 884 case SCTP_STATE_ESTABLISHED: 885 case SCTP_STATE_SHUTDOWN_PENDING: 886 case SCTP_STATE_SHUTDOWN_RECEIVED: 887 /* 888 * RFC 2960 6.1 Transmission of DATA Chunks 889 * 890 * C) When the time comes for the sender to transmit, 891 * before sending new DATA chunks, the sender MUST 892 * first transmit any outstanding DATA chunks which 893 * are marked for retransmission (limited by the 894 * current cwnd). 895 */ 896 if (!list_empty(&q->retransmit)) { 897 if (transport == asoc->peer.retran_path) 898 goto retran; 899 900 /* Switch transports & prepare the packet. */ 901 902 transport = asoc->peer.retran_path; 903 904 if (list_empty(&transport->send_ready)) { 905 list_add_tail(&transport->send_ready, 906 &transport_list); 907 } 908 909 packet = &transport->packet; 910 sctp_packet_config(packet, vtag, 911 asoc->peer.ecn_capable); 912 retran: 913 error = sctp_outq_flush_rtx(q, packet, 914 rtx_timeout, &start_timer); 915 916 if (start_timer) 917 sctp_transport_reset_timers(transport); 918 919 /* This can happen on COOKIE-ECHO resend. Only 920 * one chunk can get bundled with a COOKIE-ECHO. 921 */ 922 if (packet->has_cookie_echo) 923 goto sctp_flush_out; 924 925 /* Don't send new data if there is still data 926 * waiting to retransmit. 927 */ 928 if (!list_empty(&q->retransmit)) 929 goto sctp_flush_out; 930 } 931 932 /* Apply Max.Burst limitation to the current transport in 933 * case it will be used for new data. We are going to 934 * rest it before we return, but we want to apply the limit 935 * to the currently queued data. 936 */ 937 if (transport) 938 sctp_transport_burst_limited(transport); 939 940 /* Finally, transmit new packets. */ 941 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) { 942 /* RFC 2960 6.5 Every DATA chunk MUST carry a valid 943 * stream identifier. 944 */ 945 if (chunk->sinfo.sinfo_stream >= 946 asoc->c.sinit_num_ostreams) { 947 948 /* Mark as failed send. */ 949 sctp_chunk_fail(chunk, SCTP_ERROR_INV_STRM); 950 sctp_chunk_free(chunk); 951 continue; 952 } 953 954 /* Has this chunk expired? */ 955 if (sctp_chunk_abandoned(chunk)) { 956 sctp_chunk_fail(chunk, 0); 957 sctp_chunk_free(chunk); 958 continue; 959 } 960 961 /* If there is a specified transport, use it. 962 * Otherwise, we want to use the active path. 963 */ 964 new_transport = chunk->transport; 965 if (!new_transport || 966 ((new_transport->state == SCTP_INACTIVE) || 967 (new_transport->state == SCTP_UNCONFIRMED))) 968 new_transport = asoc->peer.active_path; 969 970 /* Change packets if necessary. */ 971 if (new_transport != transport) { 972 transport = new_transport; 973 974 /* Schedule to have this transport's 975 * packet flushed. 976 */ 977 if (list_empty(&transport->send_ready)) { 978 list_add_tail(&transport->send_ready, 979 &transport_list); 980 } 981 982 packet = &transport->packet; 983 sctp_packet_config(packet, vtag, 984 asoc->peer.ecn_capable); 985 /* We've switched transports, so apply the 986 * Burst limit to the new transport. 987 */ 988 sctp_transport_burst_limited(transport); 989 } 990 991 SCTP_DEBUG_PRINTK("sctp_outq_flush(%p, %p[%s]), ", 992 q, chunk, 993 chunk && chunk->chunk_hdr ? 994 sctp_cname(SCTP_ST_CHUNK( 995 chunk->chunk_hdr->type)) 996 : "Illegal Chunk"); 997 998 SCTP_DEBUG_PRINTK("TX TSN 0x%x skb->head " 999 "%p skb->users %d.\n", 1000 ntohl(chunk->subh.data_hdr->tsn), 1001 chunk->skb ?chunk->skb->head : NULL, 1002 chunk->skb ? 1003 atomic_read(&chunk->skb->users) : -1); 1004 1005 /* Add the chunk to the packet. */ 1006 status = sctp_packet_transmit_chunk(packet, chunk, 0); 1007 1008 switch (status) { 1009 case SCTP_XMIT_PMTU_FULL: 1010 case SCTP_XMIT_RWND_FULL: 1011 case SCTP_XMIT_NAGLE_DELAY: 1012 /* We could not append this chunk, so put 1013 * the chunk back on the output queue. 1014 */ 1015 SCTP_DEBUG_PRINTK("sctp_outq_flush: could " 1016 "not transmit TSN: 0x%x, status: %d\n", 1017 ntohl(chunk->subh.data_hdr->tsn), 1018 status); 1019 sctp_outq_head_data(q, chunk); 1020 goto sctp_flush_out; 1021 break; 1022 1023 case SCTP_XMIT_OK: 1024 /* The sender is in the SHUTDOWN-PENDING state, 1025 * The sender MAY set the I-bit in the DATA 1026 * chunk header. 1027 */ 1028 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING) 1029 chunk->chunk_hdr->flags |= SCTP_DATA_SACK_IMM; 1030 1031 break; 1032 1033 default: 1034 BUG(); 1035 } 1036 1037 /* BUG: We assume that the sctp_packet_transmit() 1038 * call below will succeed all the time and add the 1039 * chunk to the transmitted list and restart the 1040 * timers. 1041 * It is possible that the call can fail under OOM 1042 * conditions. 1043 * 1044 * Is this really a problem? Won't this behave 1045 * like a lost TSN? 1046 */ 1047 list_add_tail(&chunk->transmitted_list, 1048 &transport->transmitted); 1049 1050 sctp_transport_reset_timers(transport); 1051 1052 q->empty = 0; 1053 1054 /* Only let one DATA chunk get bundled with a 1055 * COOKIE-ECHO chunk. 1056 */ 1057 if (packet->has_cookie_echo) 1058 goto sctp_flush_out; 1059 } 1060 break; 1061 1062 default: 1063 /* Do nothing. */ 1064 break; 1065 } 1066 1067sctp_flush_out: 1068 1069 /* Before returning, examine all the transports touched in 1070 * this call. Right now, we bluntly force clear all the 1071 * transports. Things might change after we implement Nagle. 1072 * But such an examination is still required. 1073 * 1074 * --xguo 1075 */ 1076 while ((ltransport = sctp_list_dequeue(&transport_list)) != NULL ) { 1077 struct sctp_transport *t = list_entry(ltransport, 1078 struct sctp_transport, 1079 send_ready); 1080 packet = &t->packet; 1081 if (!sctp_packet_empty(packet)) 1082 error = sctp_packet_transmit(packet); 1083 1084 /* Clear the burst limited state, if any */ 1085 sctp_transport_burst_reset(t); 1086 } 1087 1088 return error; 1089} 1090 1091/* Update unack_data based on the incoming SACK chunk */ 1092static void sctp_sack_update_unack_data(struct sctp_association *assoc, 1093 struct sctp_sackhdr *sack) 1094{ 1095 sctp_sack_variable_t *frags; 1096 __u16 unack_data; 1097 int i; 1098 1099 unack_data = assoc->next_tsn - assoc->ctsn_ack_point - 1; 1100 1101 frags = sack->variable; 1102 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); i++) { 1103 unack_data -= ((ntohs(frags[i].gab.end) - 1104 ntohs(frags[i].gab.start) + 1)); 1105 } 1106 1107 assoc->unack_data = unack_data; 1108} 1109 1110/* This is where we REALLY process a SACK. 1111 * 1112 * Process the SACK against the outqueue. Mostly, this just frees 1113 * things off the transmitted queue. 1114 */ 1115int sctp_outq_sack(struct sctp_outq *q, struct sctp_sackhdr *sack) 1116{ 1117 struct sctp_association *asoc = q->asoc; 1118 struct sctp_transport *transport; 1119 struct sctp_chunk *tchunk = NULL; 1120 struct list_head *lchunk, *transport_list, *temp; 1121 sctp_sack_variable_t *frags = sack->variable; 1122 __u32 sack_ctsn, ctsn, tsn; 1123 __u32 highest_tsn, highest_new_tsn; 1124 __u32 sack_a_rwnd; 1125 unsigned outstanding; 1126 struct sctp_transport *primary = asoc->peer.primary_path; 1127 int count_of_newacks = 0; 1128 int gap_ack_blocks; 1129 u8 accum_moved = 0; 1130 1131 /* Grab the association's destination address list. */ 1132 transport_list = &asoc->peer.transport_addr_list; 1133 1134 sack_ctsn = ntohl(sack->cum_tsn_ack); 1135 gap_ack_blocks = ntohs(sack->num_gap_ack_blocks); 1136 /* 1137 * SFR-CACC algorithm: 1138 * On receipt of a SACK the sender SHOULD execute the 1139 * following statements. 1140 * 1141 * 1) If the cumulative ack in the SACK passes next tsn_at_change 1142 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be 1143 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for 1144 * all destinations. 1145 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE 1146 * is set the receiver of the SACK MUST take the following actions: 1147 * 1148 * A) Initialize the cacc_saw_newack to 0 for all destination 1149 * addresses. 1150 * 1151 * Only bother if changeover_active is set. Otherwise, this is 1152 * totally suboptimal to do on every SACK. 1153 */ 1154 if (primary->cacc.changeover_active) { 1155 u8 clear_cycling = 0; 1156 1157 if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) { 1158 primary->cacc.changeover_active = 0; 1159 clear_cycling = 1; 1160 } 1161 1162 if (clear_cycling || gap_ack_blocks) { 1163 list_for_each_entry(transport, transport_list, 1164 transports) { 1165 if (clear_cycling) 1166 transport->cacc.cycling_changeover = 0; 1167 if (gap_ack_blocks) 1168 transport->cacc.cacc_saw_newack = 0; 1169 } 1170 } 1171 } 1172 1173 /* Get the highest TSN in the sack. */ 1174 highest_tsn = sack_ctsn; 1175 if (gap_ack_blocks) 1176 highest_tsn += ntohs(frags[gap_ack_blocks - 1].gab.end); 1177 1178 if (TSN_lt(asoc->highest_sacked, highest_tsn)) 1179 asoc->highest_sacked = highest_tsn; 1180 1181 highest_new_tsn = sack_ctsn; 1182 1183 /* Run through the retransmit queue. Credit bytes received 1184 * and free those chunks that we can. 1185 */ 1186 sctp_check_transmitted(q, &q->retransmit, NULL, sack, &highest_new_tsn); 1187 1188 /* Run through the transmitted queue. 1189 * Credit bytes received and free those chunks which we can. 1190 * 1191 * This is a MASSIVE candidate for optimization. 1192 */ 1193 list_for_each_entry(transport, transport_list, transports) { 1194 sctp_check_transmitted(q, &transport->transmitted, 1195 transport, sack, &highest_new_tsn); 1196 /* 1197 * SFR-CACC algorithm: 1198 * C) Let count_of_newacks be the number of 1199 * destinations for which cacc_saw_newack is set. 1200 */ 1201 if (transport->cacc.cacc_saw_newack) 1202 count_of_newacks ++; 1203 } 1204 1205 /* Move the Cumulative TSN Ack Point if appropriate. */ 1206 if (TSN_lt(asoc->ctsn_ack_point, sack_ctsn)) { 1207 asoc->ctsn_ack_point = sack_ctsn; 1208 accum_moved = 1; 1209 } 1210 1211 if (gap_ack_blocks) { 1212 1213 if (asoc->fast_recovery && accum_moved) 1214 highest_new_tsn = highest_tsn; 1215 1216 list_for_each_entry(transport, transport_list, transports) 1217 sctp_mark_missing(q, &transport->transmitted, transport, 1218 highest_new_tsn, count_of_newacks); 1219 } 1220 1221 /* Update unack_data field in the assoc. */ 1222 sctp_sack_update_unack_data(asoc, sack); 1223 1224 ctsn = asoc->ctsn_ack_point; 1225 1226 /* Throw away stuff rotting on the sack queue. */ 1227 list_for_each_safe(lchunk, temp, &q->sacked) { 1228 tchunk = list_entry(lchunk, struct sctp_chunk, 1229 transmitted_list); 1230 tsn = ntohl(tchunk->subh.data_hdr->tsn); 1231 if (TSN_lte(tsn, ctsn)) { 1232 list_del_init(&tchunk->transmitted_list); 1233 sctp_chunk_free(tchunk); 1234 } 1235 } 1236 1237 /* ii) Set rwnd equal to the newly received a_rwnd minus the 1238 * number of bytes still outstanding after processing the 1239 * Cumulative TSN Ack and the Gap Ack Blocks. 1240 */ 1241 1242 sack_a_rwnd = ntohl(sack->a_rwnd); 1243 outstanding = q->outstanding_bytes; 1244 1245 if (outstanding < sack_a_rwnd) 1246 sack_a_rwnd -= outstanding; 1247 else 1248 sack_a_rwnd = 0; 1249 1250 asoc->peer.rwnd = sack_a_rwnd; 1251 1252 sctp_generate_fwdtsn(q, sack_ctsn); 1253 1254 SCTP_DEBUG_PRINTK("%s: sack Cumulative TSN Ack is 0x%x.\n", 1255 __func__, sack_ctsn); 1256 SCTP_DEBUG_PRINTK("%s: Cumulative TSN Ack of association, " 1257 "%p is 0x%x. Adv peer ack point: 0x%x\n", 1258 __func__, asoc, ctsn, asoc->adv_peer_ack_point); 1259 1260 /* See if all chunks are acked. 1261 * Make sure the empty queue handler will get run later. 1262 */ 1263 q->empty = (list_empty(&q->out_chunk_list) && 1264 list_empty(&q->retransmit)); 1265 if (!q->empty) 1266 goto finish; 1267 1268 list_for_each_entry(transport, transport_list, transports) { 1269 q->empty = q->empty && list_empty(&transport->transmitted); 1270 if (!q->empty) 1271 goto finish; 1272 } 1273 1274 SCTP_DEBUG_PRINTK("sack queue is empty.\n"); 1275finish: 1276 return q->empty; 1277} 1278 1279/* Is the outqueue empty? */ 1280int sctp_outq_is_empty(const struct sctp_outq *q) 1281{ 1282 return q->empty; 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 */ 1299static void sctp_check_transmitted(struct sctp_outq *q, 1300 struct list_head *transmitted_queue, 1301 struct sctp_transport *transport, 1302 struct sctp_sackhdr *sack, 1303 __u32 *highest_new_tsn_in_sack) 1304{ 1305 struct list_head *lchunk; 1306 struct sctp_chunk *tchunk; 1307 struct list_head tlist; 1308 __u32 tsn; 1309 __u32 sack_ctsn; 1310 __u32 rtt; 1311 __u8 restart_timer = 0; 1312 int bytes_acked = 0; 1313 int migrate_bytes = 0; 1314 1315 /* These state variables are for coherent debug output. --xguo */ 1316 1317#if SCTP_DEBUG 1318 __u32 dbg_ack_tsn = 0; /* An ACKed TSN range starts here... */ 1319 __u32 dbg_last_ack_tsn = 0; /* ...and finishes here. */ 1320 __u32 dbg_kept_tsn = 0; /* An un-ACKed range starts here... */ 1321 __u32 dbg_last_kept_tsn = 0; /* ...and finishes here. */ 1322 1323 /* 0 : The last TSN was ACKed. 1324 * 1 : The last TSN was NOT ACKed (i.e. KEPT). 1325 * -1: We need to initialize. 1326 */ 1327 int dbg_prt_state = -1; 1328#endif /* SCTP_DEBUG */ 1329 1330 sack_ctsn = ntohl(sack->cum_tsn_ack); 1331 1332 INIT_LIST_HEAD(&tlist); 1333 1334 /* The while loop will skip empty transmitted queues. */ 1335 while (NULL != (lchunk = sctp_list_dequeue(transmitted_queue))) { 1336 tchunk = list_entry(lchunk, struct sctp_chunk, 1337 transmitted_list); 1338 1339 if (sctp_chunk_abandoned(tchunk)) { 1340 /* Move the chunk to abandoned list. */ 1341 sctp_insert_list(&q->abandoned, lchunk); 1342 1343 /* If this chunk has not been acked, stop 1344 * considering it as 'outstanding'. 1345 */ 1346 if (!tchunk->tsn_gap_acked) { 1347 if (tchunk->transport) 1348 tchunk->transport->flight_size -= 1349 sctp_data_size(tchunk); 1350 q->outstanding_bytes -= sctp_data_size(tchunk); 1351 } 1352 continue; 1353 } 1354 1355 tsn = ntohl(tchunk->subh.data_hdr->tsn); 1356 if (sctp_acked(sack, tsn)) { 1357 /* If this queue is the retransmit queue, the 1358 * retransmit timer has already reclaimed 1359 * the outstanding bytes for this chunk, so only 1360 * count bytes associated with a transport. 1361 */ 1362 if (transport) { 1363 /* If this chunk is being used for RTT 1364 * measurement, calculate the RTT and update 1365 * the RTO using this value. 1366 * 1367 * 6.3.1 C5) Karn's algorithm: RTT measurements 1368 * MUST NOT be made using packets that were 1369 * retransmitted (and thus for which it is 1370 * ambiguous whether the reply was for the 1371 * first instance of the packet or a later 1372 * instance). 1373 */ 1374 if (!tchunk->tsn_gap_acked && 1375 tchunk->rtt_in_progress) { 1376 tchunk->rtt_in_progress = 0; 1377 rtt = jiffies - tchunk->sent_at; 1378 sctp_transport_update_rto(transport, 1379 rtt); 1380 } 1381 } 1382 1383 /* If the chunk hasn't been marked as ACKED, 1384 * mark it and account bytes_acked if the 1385 * chunk had a valid transport (it will not 1386 * have a transport if ASCONF had deleted it 1387 * while DATA was outstanding). 1388 */ 1389 if (!tchunk->tsn_gap_acked) { 1390 tchunk->tsn_gap_acked = 1; 1391 *highest_new_tsn_in_sack = tsn; 1392 bytes_acked += sctp_data_size(tchunk); 1393 if (!tchunk->transport) 1394 migrate_bytes += sctp_data_size(tchunk); 1395 } 1396 1397 if (TSN_lte(tsn, sack_ctsn)) { 1398 /* RFC 2960 6.3.2 Retransmission Timer Rules 1399 * 1400 * R3) Whenever a SACK is received 1401 * that acknowledges the DATA chunk 1402 * with the earliest outstanding TSN 1403 * for that address, restart T3-rtx 1404 * timer for that address with its 1405 * current RTO. 1406 */ 1407 restart_timer = 1; 1408 1409 if (!tchunk->tsn_gap_acked) { 1410 /* 1411 * SFR-CACC algorithm: 1412 * 2) If the SACK contains gap acks 1413 * and the flag CHANGEOVER_ACTIVE is 1414 * set the receiver of the SACK MUST 1415 * take the following action: 1416 * 1417 * B) For each TSN t being acked that 1418 * has not been acked in any SACK so 1419 * far, set cacc_saw_newack to 1 for 1420 * the destination that the TSN was 1421 * sent to. 1422 */ 1423 if (transport && 1424 sack->num_gap_ack_blocks && 1425 q->asoc->peer.primary_path->cacc. 1426 changeover_active) 1427 transport->cacc.cacc_saw_newack 1428 = 1; 1429 } 1430 1431 list_add_tail(&tchunk->transmitted_list, 1432 &q->sacked); 1433 } else { 1434 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2 1435 * M2) Each time a SACK arrives reporting 1436 * 'Stray DATA chunk(s)' record the highest TSN 1437 * reported as newly acknowledged, call this 1438 * value 'HighestTSNinSack'. A newly 1439 * acknowledged DATA chunk is one not 1440 * previously acknowledged in a SACK. 1441 * 1442 * When the SCTP sender of data receives a SACK 1443 * chunk that acknowledges, for the first time, 1444 * the receipt of a DATA chunk, all the still 1445 * unacknowledged DATA chunks whose TSN is 1446 * older than that newly acknowledged DATA 1447 * chunk, are qualified as 'Stray DATA chunks'. 1448 */ 1449 list_add_tail(lchunk, &tlist); 1450 } 1451 1452#if SCTP_DEBUG 1453 switch (dbg_prt_state) { 1454 case 0: /* last TSN was ACKed */ 1455 if (dbg_last_ack_tsn + 1 == tsn) { 1456 /* This TSN belongs to the 1457 * current ACK range. 1458 */ 1459 break; 1460 } 1461 1462 if (dbg_last_ack_tsn != dbg_ack_tsn) { 1463 /* Display the end of the 1464 * current range. 1465 */ 1466 SCTP_DEBUG_PRINTK("-%08x", 1467 dbg_last_ack_tsn); 1468 } 1469 1470 /* Start a new range. */ 1471 SCTP_DEBUG_PRINTK(",%08x", tsn); 1472 dbg_ack_tsn = tsn; 1473 break; 1474 1475 case 1: /* The last TSN was NOT ACKed. */ 1476 if (dbg_last_kept_tsn != dbg_kept_tsn) { 1477 /* Display the end of current range. */ 1478 SCTP_DEBUG_PRINTK("-%08x", 1479 dbg_last_kept_tsn); 1480 } 1481 1482 SCTP_DEBUG_PRINTK("\n"); 1483 1484 /* FALL THROUGH... */ 1485 default: 1486 /* This is the first-ever TSN we examined. */ 1487 /* Start a new range of ACK-ed TSNs. */ 1488 SCTP_DEBUG_PRINTK("ACKed: %08x", tsn); 1489 dbg_prt_state = 0; 1490 dbg_ack_tsn = tsn; 1491 } 1492 1493 dbg_last_ack_tsn = tsn; 1494#endif /* SCTP_DEBUG */ 1495 1496 } else { 1497 if (tchunk->tsn_gap_acked) { 1498 SCTP_DEBUG_PRINTK("%s: Receiver reneged on " 1499 "data TSN: 0x%x\n", 1500 __func__, 1501 tsn); 1502 tchunk->tsn_gap_acked = 0; 1503 1504 if (tchunk->transport) 1505 bytes_acked -= sctp_data_size(tchunk); 1506 1507 /* RFC 2960 6.3.2 Retransmission Timer Rules 1508 * 1509 * R4) Whenever a SACK is received missing a 1510 * TSN that was previously acknowledged via a 1511 * Gap Ack Block, start T3-rtx for the 1512 * destination address to which the DATA 1513 * chunk was originally 1514 * transmitted if it is not already running. 1515 */ 1516 restart_timer = 1; 1517 } 1518 1519 list_add_tail(lchunk, &tlist); 1520 1521#if SCTP_DEBUG 1522 /* See the above comments on ACK-ed TSNs. */ 1523 switch (dbg_prt_state) { 1524 case 1: 1525 if (dbg_last_kept_tsn + 1 == tsn) 1526 break; 1527 1528 if (dbg_last_kept_tsn != dbg_kept_tsn) 1529 SCTP_DEBUG_PRINTK("-%08x", 1530 dbg_last_kept_tsn); 1531 1532 SCTP_DEBUG_PRINTK(",%08x", tsn); 1533 dbg_kept_tsn = tsn; 1534 break; 1535 1536 case 0: 1537 if (dbg_last_ack_tsn != dbg_ack_tsn) 1538 SCTP_DEBUG_PRINTK("-%08x", 1539 dbg_last_ack_tsn); 1540 SCTP_DEBUG_PRINTK("\n"); 1541 1542 /* FALL THROUGH... */ 1543 default: 1544 SCTP_DEBUG_PRINTK("KEPT: %08x",tsn); 1545 dbg_prt_state = 1; 1546 dbg_kept_tsn = tsn; 1547 } 1548 1549 dbg_last_kept_tsn = tsn; 1550#endif /* SCTP_DEBUG */ 1551 } 1552 } 1553 1554#if SCTP_DEBUG 1555 /* Finish off the last range, displaying its ending TSN. */ 1556 switch (dbg_prt_state) { 1557 case 0: 1558 if (dbg_last_ack_tsn != dbg_ack_tsn) { 1559 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_ack_tsn); 1560 } else { 1561 SCTP_DEBUG_PRINTK("\n"); 1562 } 1563 break; 1564 1565 case 1: 1566 if (dbg_last_kept_tsn != dbg_kept_tsn) { 1567 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_kept_tsn); 1568 } else { 1569 SCTP_DEBUG_PRINTK("\n"); 1570 } 1571 } 1572#endif /* SCTP_DEBUG */ 1573 if (transport) { 1574 if (bytes_acked) { 1575 /* We may have counted DATA that was migrated 1576 * to this transport due to DEL-IP operation. 1577 * Subtract those bytes, since the were never 1578 * send on this transport and shouldn't be 1579 * credited to this transport. 1580 */ 1581 bytes_acked -= migrate_bytes; 1582 1583 /* 8.2. When an outstanding TSN is acknowledged, 1584 * the endpoint shall clear the error counter of 1585 * the destination transport address to which the 1586 * DATA chunk was last sent. 1587 * The association's overall error counter is 1588 * also cleared. 1589 */ 1590 transport->error_count = 0; 1591 transport->asoc->overall_error_count = 0; 1592 1593 /* Mark the destination transport address as 1594 * active if it is not so marked. 1595 */ 1596 if ((transport->state == SCTP_INACTIVE) || 1597 (transport->state == SCTP_UNCONFIRMED)) { 1598 sctp_assoc_control_transport( 1599 transport->asoc, 1600 transport, 1601 SCTP_TRANSPORT_UP, 1602 SCTP_RECEIVED_SACK); 1603 } 1604 1605 sctp_transport_raise_cwnd(transport, sack_ctsn, 1606 bytes_acked); 1607 1608 transport->flight_size -= bytes_acked; 1609 if (transport->flight_size == 0) 1610 transport->partial_bytes_acked = 0; 1611 q->outstanding_bytes -= bytes_acked + migrate_bytes; 1612 } else { 1613 /* RFC 2960 6.1, sctpimpguide-06 2.15.2 1614 * When a sender is doing zero window probing, it 1615 * should not timeout the association if it continues 1616 * to receive new packets from the receiver. The 1617 * reason is that the receiver MAY keep its window 1618 * closed for an indefinite time. 1619 * A sender is doing zero window probing when the 1620 * receiver's advertised window is zero, and there is 1621 * only one data chunk in flight to the receiver. 1622 */ 1623 if (!q->asoc->peer.rwnd && 1624 !list_empty(&tlist) && 1625 (sack_ctsn+2 == q->asoc->next_tsn)) { 1626 SCTP_DEBUG_PRINTK("%s: SACK received for zero " 1627 "window probe: %u\n", 1628 __func__, sack_ctsn); 1629 q->asoc->overall_error_count = 0; 1630 transport->error_count = 0; 1631 } 1632 } 1633 1634 /* RFC 2960 6.3.2 Retransmission Timer Rules 1635 * 1636 * R2) Whenever all outstanding data sent to an address have 1637 * been acknowledged, turn off the T3-rtx timer of that 1638 * address. 1639 */ 1640 if (!transport->flight_size) { 1641 if (timer_pending(&transport->T3_rtx_timer) && 1642 del_timer(&transport->T3_rtx_timer)) { 1643 sctp_transport_put(transport); 1644 } 1645 } else if (restart_timer) { 1646 if (!mod_timer(&transport->T3_rtx_timer, 1647 jiffies + transport->rto)) 1648 sctp_transport_hold(transport); 1649 } 1650 } 1651 1652 list_splice(&tlist, transmitted_queue); 1653} 1654 1655/* Mark chunks as missing and consequently may get retransmitted. */ 1656static void sctp_mark_missing(struct sctp_outq *q, 1657 struct list_head *transmitted_queue, 1658 struct sctp_transport *transport, 1659 __u32 highest_new_tsn_in_sack, 1660 int count_of_newacks) 1661{ 1662 struct sctp_chunk *chunk; 1663 __u32 tsn; 1664 char do_fast_retransmit = 0; 1665 struct sctp_association *asoc = q->asoc; 1666 struct sctp_transport *primary = asoc->peer.primary_path; 1667 1668 list_for_each_entry(chunk, transmitted_queue, transmitted_list) { 1669 1670 tsn = ntohl(chunk->subh.data_hdr->tsn); 1671 1672 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all 1673 * 'Unacknowledged TSN's', if the TSN number of an 1674 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack' 1675 * value, increment the 'TSN.Missing.Report' count on that 1676 * chunk if it has NOT been fast retransmitted or marked for 1677 * fast retransmit already. 1678 */ 1679 if (chunk->fast_retransmit == SCTP_CAN_FRTX && 1680 !chunk->tsn_gap_acked && 1681 TSN_lt(tsn, highest_new_tsn_in_sack)) { 1682 1683 /* SFR-CACC may require us to skip marking 1684 * this chunk as missing. 1685 */ 1686 if (!transport || !sctp_cacc_skip(primary, transport, 1687 count_of_newacks, tsn)) { 1688 chunk->tsn_missing_report++; 1689 1690 SCTP_DEBUG_PRINTK( 1691 "%s: TSN 0x%x missing counter: %d\n", 1692 __func__, tsn, 1693 chunk->tsn_missing_report); 1694 } 1695 } 1696 /* 1697 * M4) If any DATA chunk is found to have a 1698 * 'TSN.Missing.Report' 1699 * value larger than or equal to 3, mark that chunk for 1700 * retransmission and start the fast retransmit procedure. 1701 */ 1702 1703 if (chunk->tsn_missing_report >= 3) { 1704 chunk->fast_retransmit = SCTP_NEED_FRTX; 1705 do_fast_retransmit = 1; 1706 } 1707 } 1708 1709 if (transport) { 1710 if (do_fast_retransmit) 1711 sctp_retransmit(q, transport, SCTP_RTXR_FAST_RTX); 1712 1713 SCTP_DEBUG_PRINTK("%s: transport: %p, cwnd: %d, " 1714 "ssthresh: %d, flight_size: %d, pba: %d\n", 1715 __func__, transport, transport->cwnd, 1716 transport->ssthresh, transport->flight_size, 1717 transport->partial_bytes_acked); 1718 } 1719} 1720 1721/* Is the given TSN acked by this packet? */ 1722static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn) 1723{ 1724 int i; 1725 sctp_sack_variable_t *frags; 1726 __u16 gap; 1727 __u32 ctsn = ntohl(sack->cum_tsn_ack); 1728 1729 if (TSN_lte(tsn, ctsn)) 1730 goto pass; 1731 1732 /* 3.3.4 Selective Acknowledgement (SACK) (3): 1733 * 1734 * Gap Ack Blocks: 1735 * These fields contain the Gap Ack Blocks. They are repeated 1736 * for each Gap Ack Block up to the number of Gap Ack Blocks 1737 * defined in the Number of Gap Ack Blocks field. All DATA 1738 * chunks with TSNs greater than or equal to (Cumulative TSN 1739 * Ack + Gap Ack Block Start) and less than or equal to 1740 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack 1741 * Block are assumed to have been received correctly. 1742 */ 1743 1744 frags = sack->variable; 1745 gap = tsn - ctsn; 1746 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); ++i) { 1747 if (TSN_lte(ntohs(frags[i].gab.start), gap) && 1748 TSN_lte(gap, ntohs(frags[i].gab.end))) 1749 goto pass; 1750 } 1751 1752 return 0; 1753pass: 1754 return 1; 1755} 1756 1757static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip *skiplist, 1758 int nskips, __be16 stream) 1759{ 1760 int i; 1761 1762 for (i = 0; i < nskips; i++) { 1763 if (skiplist[i].stream == stream) 1764 return i; 1765 } 1766 return i; 1767} 1768 1769/* Create and add a fwdtsn chunk to the outq's control queue if needed. */ 1770static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 ctsn) 1771{ 1772 struct sctp_association *asoc = q->asoc; 1773 struct sctp_chunk *ftsn_chunk = NULL; 1774 struct sctp_fwdtsn_skip ftsn_skip_arr[10]; 1775 int nskips = 0; 1776 int skip_pos = 0; 1777 __u32 tsn; 1778 struct sctp_chunk *chunk; 1779 struct list_head *lchunk, *temp; 1780 1781 if (!asoc->peer.prsctp_capable) 1782 return; 1783 1784 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the 1785 * received SACK. 1786 * 1787 * If (Advanced.Peer.Ack.Point < SackCumAck), then update 1788 * Advanced.Peer.Ack.Point to be equal to SackCumAck. 1789 */ 1790 if (TSN_lt(asoc->adv_peer_ack_point, ctsn)) 1791 asoc->adv_peer_ack_point = ctsn; 1792 1793 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point" 1794 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as 1795 * the chunk next in the out-queue space is marked as "abandoned" as 1796 * shown in the following example: 1797 * 1798 * Assuming that a SACK arrived with the Cumulative TSN ACK 102 1799 * and the Advanced.Peer.Ack.Point is updated to this value: 1800 * 1801 * out-queue at the end of ==> out-queue after Adv.Ack.Point 1802 * normal SACK processing local advancement 1803 * ... ... 1804 * Adv.Ack.Pt-> 102 acked 102 acked 1805 * 103 abandoned 103 abandoned 1806 * 104 abandoned Adv.Ack.P-> 104 abandoned 1807 * 105 105 1808 * 106 acked 106 acked 1809 * ... ... 1810 * 1811 * In this example, the data sender successfully advanced the 1812 * "Advanced.Peer.Ack.Point" from 102 to 104 locally. 1813 */ 1814 list_for_each_safe(lchunk, temp, &q->abandoned) { 1815 chunk = list_entry(lchunk, struct sctp_chunk, 1816 transmitted_list); 1817 tsn = ntohl(chunk->subh.data_hdr->tsn); 1818 1819 /* Remove any chunks in the abandoned queue that are acked by 1820 * the ctsn. 1821 */ 1822 if (TSN_lte(tsn, ctsn)) { 1823 list_del_init(lchunk); 1824 sctp_chunk_free(chunk); 1825 } else { 1826 if (TSN_lte(tsn, asoc->adv_peer_ack_point+1)) { 1827 asoc->adv_peer_ack_point = tsn; 1828 if (chunk->chunk_hdr->flags & 1829 SCTP_DATA_UNORDERED) 1830 continue; 1831 skip_pos = sctp_get_skip_pos(&ftsn_skip_arr[0], 1832 nskips, 1833 chunk->subh.data_hdr->stream); 1834 ftsn_skip_arr[skip_pos].stream = 1835 chunk->subh.data_hdr->stream; 1836 ftsn_skip_arr[skip_pos].ssn = 1837 chunk->subh.data_hdr->ssn; 1838 if (skip_pos == nskips) 1839 nskips++; 1840 if (nskips == 10) 1841 break; 1842 } else 1843 break; 1844 } 1845 } 1846 1847 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point" 1848 * is greater than the Cumulative TSN ACK carried in the received 1849 * SACK, the data sender MUST send the data receiver a FORWARD TSN 1850 * chunk containing the latest value of the 1851 * "Advanced.Peer.Ack.Point". 1852 * 1853 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD 1854 * list each stream and sequence number in the forwarded TSN. This 1855 * information will enable the receiver to easily find any 1856 * stranded TSN's waiting on stream reorder queues. Each stream 1857 * SHOULD only be reported once; this means that if multiple 1858 * abandoned messages occur in the same stream then only the 1859 * highest abandoned stream sequence number is reported. If the 1860 * total size of the FORWARD TSN does NOT fit in a single MTU then 1861 * the sender of the FORWARD TSN SHOULD lower the 1862 * Advanced.Peer.Ack.Point to the last TSN that will fit in a 1863 * single MTU. 1864 */ 1865 if (asoc->adv_peer_ack_point > ctsn) 1866 ftsn_chunk = sctp_make_fwdtsn(asoc, asoc->adv_peer_ack_point, 1867 nskips, &ftsn_skip_arr[0]); 1868 1869 if (ftsn_chunk) { 1870 list_add_tail(&ftsn_chunk->list, &q->control_chunk_list); 1871 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 1872 } 1873} 1874