1 /* SCTP kernel reference 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 reference Implementation 8 * 9 * These functions implement the sctp_outq class. The outqueue handles 10 * bundling and queueing of outgoing SCTP chunks. 11 * 12 * The SCTP reference 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 * The SCTP reference 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 <net/sock.h> /* For skb_set_owner_w */ 54 55 #include <net/sctp/sctp.h> 56 #include <net/sctp/sm.h> 57 58 /* Declare internal functions here. */ 59 static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn); 60 static void sctp_check_transmitted(struct sctp_outq *q, 61 struct list_head *transmitted_queue, 62 struct sctp_transport *transport, 63 struct sctp_sackhdr *sack, 64 __u32 highest_new_tsn); 65 66 static void sctp_mark_missing(struct sctp_outq *q, 67 struct list_head *transmitted_queue, 68 struct sctp_transport *transport, 69 __u32 highest_new_tsn, 70 int count_of_newacks); 71 72 static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 sack_ctsn); 73 74 /* Add data to the front of the queue. */ 75 static inline void sctp_outq_head_data(struct sctp_outq *q, 76 struct sctp_chunk *ch) 77 { 78 list_add(&ch->list, &q->out_chunk_list); 79 q->out_qlen += ch->skb->len; 80 return; 81 } 82 83 /* Take data from the front of the queue. */ 84 static inline struct sctp_chunk *sctp_outq_dequeue_data(struct sctp_outq *q) 85 { 86 struct sctp_chunk *ch = NULL; 87 88 if (!list_empty(&q->out_chunk_list)) { 89 struct list_head *entry = q->out_chunk_list.next; 90 91 ch = list_entry(entry, struct sctp_chunk, list); 92 list_del_init(entry); 93 q->out_qlen -= ch->skb->len; 94 } 95 return ch; 96 } 97 /* Add data chunk to the end of the queue. */ 98 static inline void sctp_outq_tail_data(struct sctp_outq *q, 99 struct sctp_chunk *ch) 100 { 101 list_add_tail(&ch->list, &q->out_chunk_list); 102 q->out_qlen += ch->skb->len; 103 return; 104 } 105 106 /* 107 * SFR-CACC algorithm: 108 * D) If count_of_newacks is greater than or equal to 2 109 * and t was not sent to the current primary then the 110 * sender MUST NOT increment missing report count for t. 111 */ 112 static inline int sctp_cacc_skip_3_1_d(struct sctp_transport *primary, 113 struct sctp_transport *transport, 114 int count_of_newacks) 115 { 116 if (count_of_newacks >=2 && transport != primary) 117 return 1; 118 return 0; 119 } 120 121 /* 122 * SFR-CACC algorithm: 123 * F) If count_of_newacks is less than 2, let d be the 124 * destination to which t was sent. If cacc_saw_newack 125 * is 0 for destination d, then the sender MUST NOT 126 * increment missing report count for t. 127 */ 128 static inline int sctp_cacc_skip_3_1_f(struct sctp_transport *transport, 129 int count_of_newacks) 130 { 131 if (count_of_newacks < 2 && !transport->cacc.cacc_saw_newack) 132 return 1; 133 return 0; 134 } 135 136 /* 137 * SFR-CACC algorithm: 138 * 3.1) If CYCLING_CHANGEOVER is 0, the sender SHOULD 139 * execute steps C, D, F. 140 * 141 * C has been implemented in sctp_outq_sack 142 */ 143 static inline int sctp_cacc_skip_3_1(struct sctp_transport *primary, 144 struct sctp_transport *transport, 145 int count_of_newacks) 146 { 147 if (!primary->cacc.cycling_changeover) { 148 if (sctp_cacc_skip_3_1_d(primary, transport, count_of_newacks)) 149 return 1; 150 if (sctp_cacc_skip_3_1_f(transport, count_of_newacks)) 151 return 1; 152 return 0; 153 } 154 return 0; 155 } 156 157 /* 158 * SFR-CACC algorithm: 159 * 3.2) Else if CYCLING_CHANGEOVER is 1, and t is less 160 * than next_tsn_at_change of the current primary, then 161 * the sender MUST NOT increment missing report count 162 * for t. 163 */ 164 static inline int sctp_cacc_skip_3_2(struct sctp_transport *primary, __u32 tsn) 165 { 166 if (primary->cacc.cycling_changeover && 167 TSN_lt(tsn, primary->cacc.next_tsn_at_change)) 168 return 1; 169 return 0; 170 } 171 172 /* 173 * SFR-CACC algorithm: 174 * 3) If the missing report count for TSN t is to be 175 * incremented according to [RFC2960] and 176 * [SCTP_STEWART-2002], and CHANGEOVER_ACTIVE is set, 177 * then the sender MUST futher execute steps 3.1 and 178 * 3.2 to determine if the missing report count for 179 * TSN t SHOULD NOT be incremented. 180 * 181 * 3.3) If 3.1 and 3.2 do not dictate that the missing 182 * report count for t should not be incremented, then 183 * the sender SOULD increment missing report count for 184 * t (according to [RFC2960] and [SCTP_STEWART_2002]). 185 */ 186 static inline int sctp_cacc_skip(struct sctp_transport *primary, 187 struct sctp_transport *transport, 188 int count_of_newacks, 189 __u32 tsn) 190 { 191 if (primary->cacc.changeover_active && 192 (sctp_cacc_skip_3_1(primary, transport, count_of_newacks) 193 || sctp_cacc_skip_3_2(primary, tsn))) 194 return 1; 195 return 0; 196 } 197 198 /* Initialize an existing sctp_outq. This does the boring stuff. 199 * You still need to define handlers if you really want to DO 200 * something with this structure... 201 */ 202 void sctp_outq_init(struct sctp_association *asoc, struct sctp_outq *q) 203 { 204 q->asoc = asoc; 205 INIT_LIST_HEAD(&q->out_chunk_list); 206 INIT_LIST_HEAD(&q->control_chunk_list); 207 INIT_LIST_HEAD(&q->retransmit); 208 INIT_LIST_HEAD(&q->sacked); 209 INIT_LIST_HEAD(&q->abandoned); 210 211 q->outstanding_bytes = 0; 212 q->empty = 1; 213 q->cork = 0; 214 215 q->malloced = 0; 216 q->out_qlen = 0; 217 } 218 219 /* Free the outqueue structure and any related pending chunks. 220 */ 221 void sctp_outq_teardown(struct sctp_outq *q) 222 { 223 struct sctp_transport *transport; 224 struct list_head *lchunk, *pos, *temp; 225 struct sctp_chunk *chunk, *tmp; 226 227 /* Throw away unacknowledged chunks. */ 228 list_for_each(pos, &q->asoc->peer.transport_addr_list) { 229 transport = list_entry(pos, struct sctp_transport, transports); 230 while ((lchunk = sctp_list_dequeue(&transport->transmitted)) != NULL) { 231 chunk = list_entry(lchunk, struct sctp_chunk, 232 transmitted_list); 233 /* Mark as part of a failed message. */ 234 sctp_chunk_fail(chunk, q->error); 235 sctp_chunk_free(chunk); 236 } 237 } 238 239 /* Throw away chunks that have been gap ACKed. */ 240 list_for_each_safe(lchunk, temp, &q->sacked) { 241 list_del_init(lchunk); 242 chunk = list_entry(lchunk, struct sctp_chunk, 243 transmitted_list); 244 sctp_chunk_fail(chunk, q->error); 245 sctp_chunk_free(chunk); 246 } 247 248 /* Throw away any chunks in the retransmit queue. */ 249 list_for_each_safe(lchunk, temp, &q->retransmit) { 250 list_del_init(lchunk); 251 chunk = list_entry(lchunk, struct sctp_chunk, 252 transmitted_list); 253 sctp_chunk_fail(chunk, q->error); 254 sctp_chunk_free(chunk); 255 } 256 257 /* Throw away any chunks that are in the abandoned queue. */ 258 list_for_each_safe(lchunk, temp, &q->abandoned) { 259 list_del_init(lchunk); 260 chunk = list_entry(lchunk, struct sctp_chunk, 261 transmitted_list); 262 sctp_chunk_fail(chunk, q->error); 263 sctp_chunk_free(chunk); 264 } 265 266 /* Throw away any leftover data chunks. */ 267 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) { 268 269 /* Mark as send failure. */ 270 sctp_chunk_fail(chunk, q->error); 271 sctp_chunk_free(chunk); 272 } 273 274 q->error = 0; 275 276 /* Throw away any leftover control chunks. */ 277 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) { 278 list_del_init(&chunk->list); 279 sctp_chunk_free(chunk); 280 } 281 } 282 283 /* Free the outqueue structure and any related pending chunks. */ 284 void sctp_outq_free(struct sctp_outq *q) 285 { 286 /* Throw away leftover chunks. */ 287 sctp_outq_teardown(q); 288 289 /* If we were kmalloc()'d, free the memory. */ 290 if (q->malloced) 291 kfree(q); 292 } 293 294 /* Put a new chunk in an sctp_outq. */ 295 int sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk) 296 { 297 int error = 0; 298 299 SCTP_DEBUG_PRINTK("sctp_outq_tail(%p, %p[%s])\n", 300 q, chunk, chunk && chunk->chunk_hdr ? 301 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) 302 : "Illegal Chunk"); 303 304 /* If it is data, queue it up, otherwise, send it 305 * immediately. 306 */ 307 if (SCTP_CID_DATA == chunk->chunk_hdr->type) { 308 /* Is it OK to queue data chunks? */ 309 /* From 9. Termination of Association 310 * 311 * When either endpoint performs a shutdown, the 312 * association on each peer will stop accepting new 313 * data from its user and only deliver data in queue 314 * at the time of sending or receiving the SHUTDOWN 315 * chunk. 316 */ 317 switch (q->asoc->state) { 318 case SCTP_STATE_EMPTY: 319 case SCTP_STATE_CLOSED: 320 case SCTP_STATE_SHUTDOWN_PENDING: 321 case SCTP_STATE_SHUTDOWN_SENT: 322 case SCTP_STATE_SHUTDOWN_RECEIVED: 323 case SCTP_STATE_SHUTDOWN_ACK_SENT: 324 /* Cannot send after transport endpoint shutdown */ 325 error = -ESHUTDOWN; 326 break; 327 328 default: 329 SCTP_DEBUG_PRINTK("outqueueing (%p, %p[%s])\n", 330 q, chunk, chunk && chunk->chunk_hdr ? 331 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) 332 : "Illegal Chunk"); 333 334 sctp_outq_tail_data(q, chunk); 335 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) 336 SCTP_INC_STATS(SCTP_MIB_OUTUNORDERCHUNKS); 337 else 338 SCTP_INC_STATS(SCTP_MIB_OUTORDERCHUNKS); 339 q->empty = 0; 340 break; 341 }; 342 } else { 343 list_add_tail(&chunk->list, &q->control_chunk_list); 344 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 345 } 346 347 if (error < 0) 348 return error; 349 350 if (!q->cork) 351 error = sctp_outq_flush(q, 0); 352 353 return error; 354 } 355 356 /* Insert a chunk into the sorted list based on the TSNs. The retransmit list 357 * and the abandoned list are in ascending order. 358 */ 359 static void sctp_insert_list(struct list_head *head, struct list_head *new) 360 { 361 struct list_head *pos; 362 struct sctp_chunk *nchunk, *lchunk; 363 __u32 ntsn, ltsn; 364 int done = 0; 365 366 nchunk = list_entry(new, struct sctp_chunk, transmitted_list); 367 ntsn = ntohl(nchunk->subh.data_hdr->tsn); 368 369 list_for_each(pos, head) { 370 lchunk = list_entry(pos, struct sctp_chunk, transmitted_list); 371 ltsn = ntohl(lchunk->subh.data_hdr->tsn); 372 if (TSN_lt(ntsn, ltsn)) { 373 list_add(new, pos->prev); 374 done = 1; 375 break; 376 } 377 } 378 if (!done) 379 list_add_tail(new, head); 380 } 381 382 /* Mark all the eligible packets on a transport for retransmission. */ 383 void sctp_retransmit_mark(struct sctp_outq *q, 384 struct sctp_transport *transport, 385 __u8 fast_retransmit) 386 { 387 struct list_head *lchunk, *ltemp; 388 struct sctp_chunk *chunk; 389 390 /* Walk through the specified transmitted queue. */ 391 list_for_each_safe(lchunk, ltemp, &transport->transmitted) { 392 chunk = list_entry(lchunk, struct sctp_chunk, 393 transmitted_list); 394 395 /* If the chunk is abandoned, move it to abandoned list. */ 396 if (sctp_chunk_abandoned(chunk)) { 397 list_del_init(lchunk); 398 sctp_insert_list(&q->abandoned, lchunk); 399 continue; 400 } 401 402 /* If we are doing retransmission due to a fast retransmit, 403 * only the chunk's that are marked for fast retransmit 404 * should be added to the retransmit queue. If we are doing 405 * retransmission due to a timeout or pmtu discovery, only the 406 * chunks that are not yet acked should be added to the 407 * retransmit queue. 408 */ 409 if ((fast_retransmit && chunk->fast_retransmit) || 410 (!fast_retransmit && !chunk->tsn_gap_acked)) { 411 /* RFC 2960 6.2.1 Processing a Received SACK 412 * 413 * C) Any time a DATA chunk is marked for 414 * retransmission (via either T3-rtx timer expiration 415 * (Section 6.3.3) or via fast retransmit 416 * (Section 7.2.4)), add the data size of those 417 * chunks to the rwnd. 418 */ 419 q->asoc->peer.rwnd += sctp_data_size(chunk); 420 q->outstanding_bytes -= sctp_data_size(chunk); 421 transport->flight_size -= sctp_data_size(chunk); 422 423 /* sctpimpguide-05 Section 2.8.2 424 * M5) If a T3-rtx timer expires, the 425 * 'TSN.Missing.Report' of all affected TSNs is set 426 * to 0. 427 */ 428 chunk->tsn_missing_report = 0; 429 430 /* If a chunk that is being used for RTT measurement 431 * has to be retransmitted, we cannot use this chunk 432 * anymore for RTT measurements. Reset rto_pending so 433 * that a new RTT measurement is started when a new 434 * data chunk is sent. 435 */ 436 if (chunk->rtt_in_progress) { 437 chunk->rtt_in_progress = 0; 438 transport->rto_pending = 0; 439 } 440 441 /* Move the chunk to the retransmit queue. The chunks 442 * on the retransmit queue are always kept in order. 443 */ 444 list_del_init(lchunk); 445 sctp_insert_list(&q->retransmit, lchunk); 446 } 447 } 448 449 SCTP_DEBUG_PRINTK("%s: transport: %p, fast_retransmit: %d, " 450 "cwnd: %d, ssthresh: %d, flight_size: %d, " 451 "pba: %d\n", __FUNCTION__, 452 transport, fast_retransmit, 453 transport->cwnd, transport->ssthresh, 454 transport->flight_size, 455 transport->partial_bytes_acked); 456 457 } 458 459 /* Mark all the eligible packets on a transport for retransmission and force 460 * one packet out. 461 */ 462 void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport, 463 sctp_retransmit_reason_t reason) 464 { 465 int error = 0; 466 __u8 fast_retransmit = 0; 467 468 switch(reason) { 469 case SCTP_RTXR_T3_RTX: 470 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_T3_RTX); 471 /* Update the retran path if the T3-rtx timer has expired for 472 * the current retran path. 473 */ 474 if (transport == transport->asoc->peer.retran_path) 475 sctp_assoc_update_retran_path(transport->asoc); 476 break; 477 case SCTP_RTXR_FAST_RTX: 478 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_FAST_RTX); 479 fast_retransmit = 1; 480 break; 481 case SCTP_RTXR_PMTUD: 482 default: 483 break; 484 } 485 486 sctp_retransmit_mark(q, transport, fast_retransmit); 487 488 /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination, 489 * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by 490 * following the procedures outlined in C1 - C5. 491 */ 492 sctp_generate_fwdtsn(q, q->asoc->ctsn_ack_point); 493 494 error = sctp_outq_flush(q, /* rtx_timeout */ 1); 495 496 if (error) 497 q->asoc->base.sk->sk_err = -error; 498 } 499 500 /* 501 * Transmit DATA chunks on the retransmit queue. Upon return from 502 * sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which 503 * need to be transmitted by the caller. 504 * We assume that pkt->transport has already been set. 505 * 506 * The return value is a normal kernel error return value. 507 */ 508 static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt, 509 int rtx_timeout, int *start_timer) 510 { 511 struct list_head *lqueue; 512 struct list_head *lchunk, *lchunk1; 513 struct sctp_transport *transport = pkt->transport; 514 sctp_xmit_t status; 515 struct sctp_chunk *chunk, *chunk1; 516 struct sctp_association *asoc; 517 int error = 0; 518 519 asoc = q->asoc; 520 lqueue = &q->retransmit; 521 522 /* RFC 2960 6.3.3 Handle T3-rtx Expiration 523 * 524 * E3) Determine how many of the earliest (i.e., lowest TSN) 525 * outstanding DATA chunks for the address for which the 526 * T3-rtx has expired will fit into a single packet, subject 527 * to the MTU constraint for the path corresponding to the 528 * destination transport address to which the retransmission 529 * is being sent (this may be different from the address for 530 * which the timer expires [see Section 6.4]). Call this value 531 * K. Bundle and retransmit those K DATA chunks in a single 532 * packet to the destination endpoint. 533 * 534 * [Just to be painfully clear, if we are retransmitting 535 * because a timeout just happened, we should send only ONE 536 * packet of retransmitted data.] 537 */ 538 lchunk = sctp_list_dequeue(lqueue); 539 540 while (lchunk) { 541 chunk = list_entry(lchunk, struct sctp_chunk, 542 transmitted_list); 543 544 /* Make sure that Gap Acked TSNs are not retransmitted. A 545 * simple approach is just to move such TSNs out of the 546 * way and into a 'transmitted' queue and skip to the 547 * next chunk. 548 */ 549 if (chunk->tsn_gap_acked) { 550 list_add_tail(lchunk, &transport->transmitted); 551 lchunk = sctp_list_dequeue(lqueue); 552 continue; 553 } 554 555 /* Attempt to append this chunk to the packet. */ 556 status = sctp_packet_append_chunk(pkt, chunk); 557 558 switch (status) { 559 case SCTP_XMIT_PMTU_FULL: 560 /* Send this packet. */ 561 if ((error = sctp_packet_transmit(pkt)) == 0) 562 *start_timer = 1; 563 564 /* If we are retransmitting, we should only 565 * send a single packet. 566 */ 567 if (rtx_timeout) { 568 list_add(lchunk, lqueue); 569 lchunk = NULL; 570 } 571 572 /* Bundle lchunk in the next round. */ 573 break; 574 575 case SCTP_XMIT_RWND_FULL: 576 /* Send this packet. */ 577 if ((error = sctp_packet_transmit(pkt)) == 0) 578 *start_timer = 1; 579 580 /* Stop sending DATA as there is no more room 581 * at the receiver. 582 */ 583 list_add(lchunk, lqueue); 584 lchunk = NULL; 585 break; 586 587 case SCTP_XMIT_NAGLE_DELAY: 588 /* Send this packet. */ 589 if ((error = sctp_packet_transmit(pkt)) == 0) 590 *start_timer = 1; 591 592 /* Stop sending DATA because of nagle delay. */ 593 list_add(lchunk, lqueue); 594 lchunk = NULL; 595 break; 596 597 default: 598 /* The append was successful, so add this chunk to 599 * the transmitted list. 600 */ 601 list_add_tail(lchunk, &transport->transmitted); 602 603 /* Mark the chunk as ineligible for fast retransmit 604 * after it is retransmitted. 605 */ 606 chunk->fast_retransmit = 0; 607 608 *start_timer = 1; 609 q->empty = 0; 610 611 /* Retrieve a new chunk to bundle. */ 612 lchunk = sctp_list_dequeue(lqueue); 613 break; 614 }; 615 616 /* If we are here due to a retransmit timeout or a fast 617 * retransmit and if there are any chunks left in the retransmit 618 * queue that could not fit in the PMTU sized packet, they need * to be marked as ineligible for a subsequent fast retransmit. 619 */ 620 if (rtx_timeout && !lchunk) { 621 list_for_each(lchunk1, lqueue) { 622 chunk1 = list_entry(lchunk1, struct sctp_chunk, 623 transmitted_list); 624 chunk1->fast_retransmit = 0; 625 } 626 } 627 } 628 629 return error; 630 } 631 632 /* Cork the outqueue so queued chunks are really queued. */ 633 int sctp_outq_uncork(struct sctp_outq *q) 634 { 635 int error = 0; 636 if (q->cork) { 637 q->cork = 0; 638 error = sctp_outq_flush(q, 0); 639 } 640 return error; 641 } 642 643 /* 644 * Try to flush an outqueue. 645 * 646 * Description: Send everything in q which we legally can, subject to 647 * congestion limitations. 648 * * Note: This function can be called from multiple contexts so appropriate 649 * locking concerns must be made. Today we use the sock lock to protect 650 * this function. 651 */ 652 int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout) 653 { 654 struct sctp_packet *packet; 655 struct sctp_packet singleton; 656 struct sctp_association *asoc = q->asoc; 657 __u16 sport = asoc->base.bind_addr.port; 658 __u16 dport = asoc->peer.port; 659 __u32 vtag = asoc->peer.i.init_tag; 660 struct sctp_transport *transport = NULL; 661 struct sctp_transport *new_transport; 662 struct sctp_chunk *chunk, *tmp; 663 sctp_xmit_t status; 664 int error = 0; 665 int start_timer = 0; 666 667 /* These transports have chunks to send. */ 668 struct list_head transport_list; 669 struct list_head *ltransport; 670 671 INIT_LIST_HEAD(&transport_list); 672 packet = NULL; 673 674 /* 675 * 6.10 Bundling 676 * ... 677 * When bundling control chunks with DATA chunks, an 678 * endpoint MUST place control chunks first in the outbound 679 * SCTP packet. The transmitter MUST transmit DATA chunks 680 * within a SCTP packet in increasing order of TSN. 681 * ... 682 */ 683 684 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) { 685 list_del_init(&chunk->list); 686 687 /* Pick the right transport to use. */ 688 new_transport = chunk->transport; 689 690 if (!new_transport) { 691 new_transport = asoc->peer.active_path; 692 } else if (new_transport->state == SCTP_INACTIVE) { 693 /* If the chunk is Heartbeat or Heartbeat Ack, 694 * send it to chunk->transport, even if it's 695 * inactive. 696 * 697 * 3.3.6 Heartbeat Acknowledgement: 698 * ... 699 * A HEARTBEAT ACK is always sent to the source IP 700 * address of the IP datagram containing the 701 * HEARTBEAT chunk to which this ack is responding. 702 * ... 703 */ 704 if (chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT && 705 chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT_ACK) 706 new_transport = asoc->peer.active_path; 707 } 708 709 /* Are we switching transports? 710 * Take care of transport locks. 711 */ 712 if (new_transport != transport) { 713 transport = new_transport; 714 if (list_empty(&transport->send_ready)) { 715 list_add_tail(&transport->send_ready, 716 &transport_list); 717 } 718 packet = &transport->packet; 719 sctp_packet_config(packet, vtag, 720 asoc->peer.ecn_capable); 721 } 722 723 switch (chunk->chunk_hdr->type) { 724 /* 725 * 6.10 Bundling 726 * ... 727 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN 728 * COMPLETE with any other chunks. [Send them immediately.] 729 */ 730 case SCTP_CID_INIT: 731 case SCTP_CID_INIT_ACK: 732 case SCTP_CID_SHUTDOWN_COMPLETE: 733 sctp_packet_init(&singleton, transport, sport, dport); 734 sctp_packet_config(&singleton, vtag, 0); 735 sctp_packet_append_chunk(&singleton, chunk); 736 error = sctp_packet_transmit(&singleton); 737 if (error < 0) 738 return error; 739 break; 740 741 case SCTP_CID_ABORT: 742 case SCTP_CID_SACK: 743 case SCTP_CID_HEARTBEAT: 744 case SCTP_CID_HEARTBEAT_ACK: 745 case SCTP_CID_SHUTDOWN: 746 case SCTP_CID_SHUTDOWN_ACK: 747 case SCTP_CID_ERROR: 748 case SCTP_CID_COOKIE_ECHO: 749 case SCTP_CID_COOKIE_ACK: 750 case SCTP_CID_ECN_ECNE: 751 case SCTP_CID_ECN_CWR: 752 case SCTP_CID_ASCONF: 753 case SCTP_CID_ASCONF_ACK: 754 case SCTP_CID_FWD_TSN: 755 sctp_packet_transmit_chunk(packet, chunk); 756 break; 757 758 default: 759 /* We built a chunk with an illegal type! */ 760 BUG(); 761 }; 762 } 763 764 /* Is it OK to send data chunks? */ 765 switch (asoc->state) { 766 case SCTP_STATE_COOKIE_ECHOED: 767 /* Only allow bundling when this packet has a COOKIE-ECHO 768 * chunk. 769 */ 770 if (!packet || !packet->has_cookie_echo) 771 break; 772 773 /* fallthru */ 774 case SCTP_STATE_ESTABLISHED: 775 case SCTP_STATE_SHUTDOWN_PENDING: 776 case SCTP_STATE_SHUTDOWN_RECEIVED: 777 /* 778 * RFC 2960 6.1 Transmission of DATA Chunks 779 * 780 * C) When the time comes for the sender to transmit, 781 * before sending new DATA chunks, the sender MUST 782 * first transmit any outstanding DATA chunks which 783 * are marked for retransmission (limited by the 784 * current cwnd). 785 */ 786 if (!list_empty(&q->retransmit)) { 787 if (transport == asoc->peer.retran_path) 788 goto retran; 789 790 /* Switch transports & prepare the packet. */ 791 792 transport = asoc->peer.retran_path; 793 794 if (list_empty(&transport->send_ready)) { 795 list_add_tail(&transport->send_ready, 796 &transport_list); 797 } 798 799 packet = &transport->packet; 800 sctp_packet_config(packet, vtag, 801 asoc->peer.ecn_capable); 802 retran: 803 error = sctp_outq_flush_rtx(q, packet, 804 rtx_timeout, &start_timer); 805 806 if (start_timer) 807 sctp_transport_reset_timers(transport); 808 809 /* This can happen on COOKIE-ECHO resend. Only 810 * one chunk can get bundled with a COOKIE-ECHO. 811 */ 812 if (packet->has_cookie_echo) 813 goto sctp_flush_out; 814 815 /* Don't send new data if there is still data 816 * waiting to retransmit. 817 */ 818 if (!list_empty(&q->retransmit)) 819 goto sctp_flush_out; 820 } 821 822 /* Finally, transmit new packets. */ 823 start_timer = 0; 824 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) { 825 /* RFC 2960 6.5 Every DATA chunk MUST carry a valid 826 * stream identifier. 827 */ 828 if (chunk->sinfo.sinfo_stream >= 829 asoc->c.sinit_num_ostreams) { 830 831 /* Mark as failed send. */ 832 sctp_chunk_fail(chunk, SCTP_ERROR_INV_STRM); 833 sctp_chunk_free(chunk); 834 continue; 835 } 836 837 /* Has this chunk expired? */ 838 if (sctp_chunk_abandoned(chunk)) { 839 sctp_chunk_fail(chunk, 0); 840 sctp_chunk_free(chunk); 841 continue; 842 } 843 844 /* If there is a specified transport, use it. 845 * Otherwise, we want to use the active path. 846 */ 847 new_transport = chunk->transport; 848 if (!new_transport || 849 new_transport->state == SCTP_INACTIVE) 850 new_transport = asoc->peer.active_path; 851 852 /* Change packets if necessary. */ 853 if (new_transport != transport) { 854 transport = new_transport; 855 856 /* Schedule to have this transport's 857 * packet flushed. 858 */ 859 if (list_empty(&transport->send_ready)) { 860 list_add_tail(&transport->send_ready, 861 &transport_list); 862 } 863 864 packet = &transport->packet; 865 sctp_packet_config(packet, vtag, 866 asoc->peer.ecn_capable); 867 } 868 869 SCTP_DEBUG_PRINTK("sctp_outq_flush(%p, %p[%s]), ", 870 q, chunk, 871 chunk && chunk->chunk_hdr ? 872 sctp_cname(SCTP_ST_CHUNK( 873 chunk->chunk_hdr->type)) 874 : "Illegal Chunk"); 875 876 SCTP_DEBUG_PRINTK("TX TSN 0x%x skb->head " 877 "%p skb->users %d.\n", 878 ntohl(chunk->subh.data_hdr->tsn), 879 chunk->skb ?chunk->skb->head : NULL, 880 chunk->skb ? 881 atomic_read(&chunk->skb->users) : -1); 882 883 /* Add the chunk to the packet. */ 884 status = sctp_packet_transmit_chunk(packet, chunk); 885 886 switch (status) { 887 case SCTP_XMIT_PMTU_FULL: 888 case SCTP_XMIT_RWND_FULL: 889 case SCTP_XMIT_NAGLE_DELAY: 890 /* We could not append this chunk, so put 891 * the chunk back on the output queue. 892 */ 893 SCTP_DEBUG_PRINTK("sctp_outq_flush: could " 894 "not transmit TSN: 0x%x, status: %d\n", 895 ntohl(chunk->subh.data_hdr->tsn), 896 status); 897 sctp_outq_head_data(q, chunk); 898 goto sctp_flush_out; 899 break; 900 901 case SCTP_XMIT_OK: 902 break; 903 904 default: 905 BUG(); 906 } 907 908 /* BUG: We assume that the sctp_packet_transmit() 909 * call below will succeed all the time and add the 910 * chunk to the transmitted list and restart the 911 * timers. 912 * It is possible that the call can fail under OOM 913 * conditions. 914 * 915 * Is this really a problem? Won't this behave 916 * like a lost TSN? 917 */ 918 list_add_tail(&chunk->transmitted_list, 919 &transport->transmitted); 920 921 sctp_transport_reset_timers(transport); 922 923 q->empty = 0; 924 925 /* Only let one DATA chunk get bundled with a 926 * COOKIE-ECHO chunk. 927 */ 928 if (packet->has_cookie_echo) 929 goto sctp_flush_out; 930 } 931 break; 932 933 default: 934 /* Do nothing. */ 935 break; 936 } 937 938 sctp_flush_out: 939 940 /* Before returning, examine all the transports touched in 941 * this call. Right now, we bluntly force clear all the 942 * transports. Things might change after we implement Nagle. 943 * But such an examination is still required. 944 * 945 * --xguo 946 */ 947 while ((ltransport = sctp_list_dequeue(&transport_list)) != NULL ) { 948 struct sctp_transport *t = list_entry(ltransport, 949 struct sctp_transport, 950 send_ready); 951 packet = &t->packet; 952 if (!sctp_packet_empty(packet)) 953 error = sctp_packet_transmit(packet); 954 } 955 956 return error; 957 } 958 959 /* Update unack_data based on the incoming SACK chunk */ 960 static void sctp_sack_update_unack_data(struct sctp_association *assoc, 961 struct sctp_sackhdr *sack) 962 { 963 sctp_sack_variable_t *frags; 964 __u16 unack_data; 965 int i; 966 967 unack_data = assoc->next_tsn - assoc->ctsn_ack_point - 1; 968 969 frags = sack->variable; 970 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); i++) { 971 unack_data -= ((ntohs(frags[i].gab.end) - 972 ntohs(frags[i].gab.start) + 1)); 973 } 974 975 assoc->unack_data = unack_data; 976 } 977 978 /* Return the highest new tsn that is acknowledged by the given SACK chunk. */ 979 static __u32 sctp_highest_new_tsn(struct sctp_sackhdr *sack, 980 struct sctp_association *asoc) 981 { 982 struct list_head *ltransport, *lchunk; 983 struct sctp_transport *transport; 984 struct sctp_chunk *chunk; 985 __u32 highest_new_tsn, tsn; 986 struct list_head *transport_list = &asoc->peer.transport_addr_list; 987 988 highest_new_tsn = ntohl(sack->cum_tsn_ack); 989 990 list_for_each(ltransport, transport_list) { 991 transport = list_entry(ltransport, struct sctp_transport, 992 transports); 993 list_for_each(lchunk, &transport->transmitted) { 994 chunk = list_entry(lchunk, struct sctp_chunk, 995 transmitted_list); 996 tsn = ntohl(chunk->subh.data_hdr->tsn); 997 998 if (!chunk->tsn_gap_acked && 999 TSN_lt(highest_new_tsn, tsn) && 1000 sctp_acked(sack, tsn)) 1001 highest_new_tsn = tsn; 1002 } 1003 } 1004 1005 return highest_new_tsn; 1006 } 1007 1008 /* This is where we REALLY process a SACK. 1009 * 1010 * Process the SACK against the outqueue. Mostly, this just frees 1011 * things off the transmitted queue. 1012 */ 1013 int sctp_outq_sack(struct sctp_outq *q, struct sctp_sackhdr *sack) 1014 { 1015 struct sctp_association *asoc = q->asoc; 1016 struct sctp_transport *transport; 1017 struct sctp_chunk *tchunk = NULL; 1018 struct list_head *lchunk, *transport_list, *pos, *temp; 1019 sctp_sack_variable_t *frags = sack->variable; 1020 __u32 sack_ctsn, ctsn, tsn; 1021 __u32 highest_tsn, highest_new_tsn; 1022 __u32 sack_a_rwnd; 1023 unsigned outstanding; 1024 struct sctp_transport *primary = asoc->peer.primary_path; 1025 int count_of_newacks = 0; 1026 1027 /* Grab the association's destination address list. */ 1028 transport_list = &asoc->peer.transport_addr_list; 1029 1030 sack_ctsn = ntohl(sack->cum_tsn_ack); 1031 1032 /* 1033 * SFR-CACC algorithm: 1034 * On receipt of a SACK the sender SHOULD execute the 1035 * following statements. 1036 * 1037 * 1) If the cumulative ack in the SACK passes next tsn_at_change 1038 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be 1039 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for 1040 * all destinations. 1041 */ 1042 if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) { 1043 primary->cacc.changeover_active = 0; 1044 list_for_each(pos, transport_list) { 1045 transport = list_entry(pos, struct sctp_transport, 1046 transports); 1047 transport->cacc.cycling_changeover = 0; 1048 } 1049 } 1050 1051 /* 1052 * SFR-CACC algorithm: 1053 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE 1054 * is set the receiver of the SACK MUST take the following actions: 1055 * 1056 * A) Initialize the cacc_saw_newack to 0 for all destination 1057 * addresses. 1058 */ 1059 if (sack->num_gap_ack_blocks > 0 && 1060 primary->cacc.changeover_active) { 1061 list_for_each(pos, transport_list) { 1062 transport = list_entry(pos, struct sctp_transport, 1063 transports); 1064 transport->cacc.cacc_saw_newack = 0; 1065 } 1066 } 1067 1068 /* Get the highest TSN in the sack. */ 1069 highest_tsn = sack_ctsn; 1070 if (sack->num_gap_ack_blocks) 1071 highest_tsn += 1072 ntohs(frags[ntohs(sack->num_gap_ack_blocks) - 1].gab.end); 1073 1074 if (TSN_lt(asoc->highest_sacked, highest_tsn)) { 1075 highest_new_tsn = highest_tsn; 1076 asoc->highest_sacked = highest_tsn; 1077 } else { 1078 highest_new_tsn = sctp_highest_new_tsn(sack, asoc); 1079 } 1080 1081 /* Run through the retransmit queue. Credit bytes received 1082 * and free those chunks that we can. 1083 */ 1084 sctp_check_transmitted(q, &q->retransmit, NULL, sack, highest_new_tsn); 1085 sctp_mark_missing(q, &q->retransmit, NULL, highest_new_tsn, 0); 1086 1087 /* Run through the transmitted queue. 1088 * Credit bytes received and free those chunks which we can. 1089 * 1090 * This is a MASSIVE candidate for optimization. 1091 */ 1092 list_for_each(pos, transport_list) { 1093 transport = list_entry(pos, struct sctp_transport, 1094 transports); 1095 sctp_check_transmitted(q, &transport->transmitted, 1096 transport, sack, highest_new_tsn); 1097 /* 1098 * SFR-CACC algorithm: 1099 * C) Let count_of_newacks be the number of 1100 * destinations for which cacc_saw_newack is set. 1101 */ 1102 if (transport->cacc.cacc_saw_newack) 1103 count_of_newacks ++; 1104 } 1105 1106 list_for_each(pos, transport_list) { 1107 transport = list_entry(pos, struct sctp_transport, 1108 transports); 1109 sctp_mark_missing(q, &transport->transmitted, transport, 1110 highest_new_tsn, count_of_newacks); 1111 } 1112 1113 /* Move the Cumulative TSN Ack Point if appropriate. */ 1114 if (TSN_lt(asoc->ctsn_ack_point, sack_ctsn)) 1115 asoc->ctsn_ack_point = sack_ctsn; 1116 1117 /* Update unack_data field in the assoc. */ 1118 sctp_sack_update_unack_data(asoc, sack); 1119 1120 ctsn = asoc->ctsn_ack_point; 1121 1122 /* Throw away stuff rotting on the sack queue. */ 1123 list_for_each_safe(lchunk, temp, &q->sacked) { 1124 tchunk = list_entry(lchunk, struct sctp_chunk, 1125 transmitted_list); 1126 tsn = ntohl(tchunk->subh.data_hdr->tsn); 1127 if (TSN_lte(tsn, ctsn)) 1128 sctp_chunk_free(tchunk); 1129 } 1130 1131 /* ii) Set rwnd equal to the newly received a_rwnd minus the 1132 * number of bytes still outstanding after processing the 1133 * Cumulative TSN Ack and the Gap Ack Blocks. 1134 */ 1135 1136 sack_a_rwnd = ntohl(sack->a_rwnd); 1137 outstanding = q->outstanding_bytes; 1138 1139 if (outstanding < sack_a_rwnd) 1140 sack_a_rwnd -= outstanding; 1141 else 1142 sack_a_rwnd = 0; 1143 1144 asoc->peer.rwnd = sack_a_rwnd; 1145 1146 sctp_generate_fwdtsn(q, sack_ctsn); 1147 1148 SCTP_DEBUG_PRINTK("%s: sack Cumulative TSN Ack is 0x%x.\n", 1149 __FUNCTION__, sack_ctsn); 1150 SCTP_DEBUG_PRINTK("%s: Cumulative TSN Ack of association, " 1151 "%p is 0x%x. Adv peer ack point: 0x%x\n", 1152 __FUNCTION__, asoc, ctsn, asoc->adv_peer_ack_point); 1153 1154 /* See if all chunks are acked. 1155 * Make sure the empty queue handler will get run later. 1156 */ 1157 q->empty = (list_empty(&q->out_chunk_list) && 1158 list_empty(&q->control_chunk_list) && 1159 list_empty(&q->retransmit)); 1160 if (!q->empty) 1161 goto finish; 1162 1163 list_for_each(pos, transport_list) { 1164 transport = list_entry(pos, struct sctp_transport, 1165 transports); 1166 q->empty = q->empty && list_empty(&transport->transmitted); 1167 if (!q->empty) 1168 goto finish; 1169 } 1170 1171 SCTP_DEBUG_PRINTK("sack queue is empty.\n"); 1172 finish: 1173 return q->empty; 1174 } 1175 1176 /* Is the outqueue empty? */ 1177 int sctp_outq_is_empty(const struct sctp_outq *q) 1178 { 1179 return q->empty; 1180 } 1181 1182 /******************************************************************** 1183 * 2nd Level Abstractions 1184 ********************************************************************/ 1185 1186 /* Go through a transport's transmitted list or the association's retransmit 1187 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked. 1188 * The retransmit list will not have an associated transport. 1189 * 1190 * I added coherent debug information output. --xguo 1191 * 1192 * Instead of printing 'sacked' or 'kept' for each TSN on the 1193 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5. 1194 * KEPT TSN6-TSN7, etc. 1195 */ 1196 static void sctp_check_transmitted(struct sctp_outq *q, 1197 struct list_head *transmitted_queue, 1198 struct sctp_transport *transport, 1199 struct sctp_sackhdr *sack, 1200 __u32 highest_new_tsn_in_sack) 1201 { 1202 struct list_head *lchunk; 1203 struct sctp_chunk *tchunk; 1204 struct list_head tlist; 1205 __u32 tsn; 1206 __u32 sack_ctsn; 1207 __u32 rtt; 1208 __u8 restart_timer = 0; 1209 int bytes_acked = 0; 1210 1211 /* These state variables are for coherent debug output. --xguo */ 1212 1213 #if SCTP_DEBUG 1214 __u32 dbg_ack_tsn = 0; /* An ACKed TSN range starts here... */ 1215 __u32 dbg_last_ack_tsn = 0; /* ...and finishes here. */ 1216 __u32 dbg_kept_tsn = 0; /* An un-ACKed range starts here... */ 1217 __u32 dbg_last_kept_tsn = 0; /* ...and finishes here. */ 1218 1219 /* 0 : The last TSN was ACKed. 1220 * 1 : The last TSN was NOT ACKed (i.e. KEPT). 1221 * -1: We need to initialize. 1222 */ 1223 int dbg_prt_state = -1; 1224 #endif /* SCTP_DEBUG */ 1225 1226 sack_ctsn = ntohl(sack->cum_tsn_ack); 1227 1228 INIT_LIST_HEAD(&tlist); 1229 1230 /* The while loop will skip empty transmitted queues. */ 1231 while (NULL != (lchunk = sctp_list_dequeue(transmitted_queue))) { 1232 tchunk = list_entry(lchunk, struct sctp_chunk, 1233 transmitted_list); 1234 1235 if (sctp_chunk_abandoned(tchunk)) { 1236 /* Move the chunk to abandoned list. */ 1237 sctp_insert_list(&q->abandoned, lchunk); 1238 continue; 1239 } 1240 1241 tsn = ntohl(tchunk->subh.data_hdr->tsn); 1242 if (sctp_acked(sack, tsn)) { 1243 /* If this queue is the retransmit queue, the 1244 * retransmit timer has already reclaimed 1245 * the outstanding bytes for this chunk, so only 1246 * count bytes associated with a transport. 1247 */ 1248 if (transport) { 1249 /* If this chunk is being used for RTT 1250 * measurement, calculate the RTT and update 1251 * the RTO using this value. 1252 * 1253 * 6.3.1 C5) Karn's algorithm: RTT measurements 1254 * MUST NOT be made using packets that were 1255 * retransmitted (and thus for which it is 1256 * ambiguous whether the reply was for the 1257 * first instance of the packet or a later 1258 * instance). 1259 */ 1260 if (!tchunk->tsn_gap_acked && 1261 !tchunk->resent && 1262 tchunk->rtt_in_progress) { 1263 rtt = jiffies - tchunk->sent_at; 1264 sctp_transport_update_rto(transport, 1265 rtt); 1266 } 1267 } 1268 if (TSN_lte(tsn, sack_ctsn)) { 1269 /* RFC 2960 6.3.2 Retransmission Timer Rules 1270 * 1271 * R3) Whenever a SACK is received 1272 * that acknowledges the DATA chunk 1273 * with the earliest outstanding TSN 1274 * for that address, restart T3-rtx 1275 * timer for that address with its 1276 * current RTO. 1277 */ 1278 restart_timer = 1; 1279 1280 if (!tchunk->tsn_gap_acked) { 1281 tchunk->tsn_gap_acked = 1; 1282 bytes_acked += sctp_data_size(tchunk); 1283 /* 1284 * SFR-CACC algorithm: 1285 * 2) If the SACK contains gap acks 1286 * and the flag CHANGEOVER_ACTIVE is 1287 * set the receiver of the SACK MUST 1288 * take the following action: 1289 * 1290 * B) For each TSN t being acked that 1291 * has not been acked in any SACK so 1292 * far, set cacc_saw_newack to 1 for 1293 * the destination that the TSN was 1294 * sent to. 1295 */ 1296 if (transport && 1297 sack->num_gap_ack_blocks && 1298 q->asoc->peer.primary_path->cacc. 1299 changeover_active) 1300 transport->cacc.cacc_saw_newack 1301 = 1; 1302 } 1303 1304 list_add_tail(&tchunk->transmitted_list, 1305 &q->sacked); 1306 } else { 1307 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2 1308 * M2) Each time a SACK arrives reporting 1309 * 'Stray DATA chunk(s)' record the highest TSN 1310 * reported as newly acknowledged, call this 1311 * value 'HighestTSNinSack'. A newly 1312 * acknowledged DATA chunk is one not 1313 * previously acknowledged in a SACK. 1314 * 1315 * When the SCTP sender of data receives a SACK 1316 * chunk that acknowledges, for the first time, 1317 * the receipt of a DATA chunk, all the still 1318 * unacknowledged DATA chunks whose TSN is 1319 * older than that newly acknowledged DATA 1320 * chunk, are qualified as 'Stray DATA chunks'. 1321 */ 1322 if (!tchunk->tsn_gap_acked) { 1323 tchunk->tsn_gap_acked = 1; 1324 bytes_acked += sctp_data_size(tchunk); 1325 } 1326 list_add_tail(lchunk, &tlist); 1327 } 1328 1329 #if SCTP_DEBUG 1330 switch (dbg_prt_state) { 1331 case 0: /* last TSN was ACKed */ 1332 if (dbg_last_ack_tsn + 1 == tsn) { 1333 /* This TSN belongs to the 1334 * current ACK range. 1335 */ 1336 break; 1337 } 1338 1339 if (dbg_last_ack_tsn != dbg_ack_tsn) { 1340 /* Display the end of the 1341 * current range. 1342 */ 1343 SCTP_DEBUG_PRINTK("-%08x", 1344 dbg_last_ack_tsn); 1345 } 1346 1347 /* Start a new range. */ 1348 SCTP_DEBUG_PRINTK(",%08x", tsn); 1349 dbg_ack_tsn = tsn; 1350 break; 1351 1352 case 1: /* The last TSN was NOT ACKed. */ 1353 if (dbg_last_kept_tsn != dbg_kept_tsn) { 1354 /* Display the end of current range. */ 1355 SCTP_DEBUG_PRINTK("-%08x", 1356 dbg_last_kept_tsn); 1357 } 1358 1359 SCTP_DEBUG_PRINTK("\n"); 1360 1361 /* FALL THROUGH... */ 1362 default: 1363 /* This is the first-ever TSN we examined. */ 1364 /* Start a new range of ACK-ed TSNs. */ 1365 SCTP_DEBUG_PRINTK("ACKed: %08x", tsn); 1366 dbg_prt_state = 0; 1367 dbg_ack_tsn = tsn; 1368 }; 1369 1370 dbg_last_ack_tsn = tsn; 1371 #endif /* SCTP_DEBUG */ 1372 1373 } else { 1374 if (tchunk->tsn_gap_acked) { 1375 SCTP_DEBUG_PRINTK("%s: Receiver reneged on " 1376 "data TSN: 0x%x\n", 1377 __FUNCTION__, 1378 tsn); 1379 tchunk->tsn_gap_acked = 0; 1380 1381 bytes_acked -= sctp_data_size(tchunk); 1382 1383 /* RFC 2960 6.3.2 Retransmission Timer Rules 1384 * 1385 * R4) Whenever a SACK is received missing a 1386 * TSN that was previously acknowledged via a 1387 * Gap Ack Block, start T3-rtx for the 1388 * destination address to which the DATA 1389 * chunk was originally 1390 * transmitted if it is not already running. 1391 */ 1392 restart_timer = 1; 1393 } 1394 1395 list_add_tail(lchunk, &tlist); 1396 1397 #if SCTP_DEBUG 1398 /* See the above comments on ACK-ed TSNs. */ 1399 switch (dbg_prt_state) { 1400 case 1: 1401 if (dbg_last_kept_tsn + 1 == tsn) 1402 break; 1403 1404 if (dbg_last_kept_tsn != dbg_kept_tsn) 1405 SCTP_DEBUG_PRINTK("-%08x", 1406 dbg_last_kept_tsn); 1407 1408 SCTP_DEBUG_PRINTK(",%08x", tsn); 1409 dbg_kept_tsn = tsn; 1410 break; 1411 1412 case 0: 1413 if (dbg_last_ack_tsn != dbg_ack_tsn) 1414 SCTP_DEBUG_PRINTK("-%08x", 1415 dbg_last_ack_tsn); 1416 SCTP_DEBUG_PRINTK("\n"); 1417 1418 /* FALL THROUGH... */ 1419 default: 1420 SCTP_DEBUG_PRINTK("KEPT: %08x",tsn); 1421 dbg_prt_state = 1; 1422 dbg_kept_tsn = tsn; 1423 }; 1424 1425 dbg_last_kept_tsn = tsn; 1426 #endif /* SCTP_DEBUG */ 1427 } 1428 } 1429 1430 #if SCTP_DEBUG 1431 /* Finish off the last range, displaying its ending TSN. */ 1432 switch (dbg_prt_state) { 1433 case 0: 1434 if (dbg_last_ack_tsn != dbg_ack_tsn) { 1435 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_ack_tsn); 1436 } else { 1437 SCTP_DEBUG_PRINTK("\n"); 1438 } 1439 break; 1440 1441 case 1: 1442 if (dbg_last_kept_tsn != dbg_kept_tsn) { 1443 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_kept_tsn); 1444 } else { 1445 SCTP_DEBUG_PRINTK("\n"); 1446 } 1447 }; 1448 #endif /* SCTP_DEBUG */ 1449 if (transport) { 1450 if (bytes_acked) { 1451 /* 8.2. When an outstanding TSN is acknowledged, 1452 * the endpoint shall clear the error counter of 1453 * the destination transport address to which the 1454 * DATA chunk was last sent. 1455 * The association's overall error counter is 1456 * also cleared. 1457 */ 1458 transport->error_count = 0; 1459 transport->asoc->overall_error_count = 0; 1460 1461 /* Mark the destination transport address as 1462 * active if it is not so marked. 1463 */ 1464 if (transport->state == SCTP_INACTIVE) { 1465 sctp_assoc_control_transport( 1466 transport->asoc, 1467 transport, 1468 SCTP_TRANSPORT_UP, 1469 SCTP_RECEIVED_SACK); 1470 } 1471 1472 sctp_transport_raise_cwnd(transport, sack_ctsn, 1473 bytes_acked); 1474 1475 transport->flight_size -= bytes_acked; 1476 q->outstanding_bytes -= bytes_acked; 1477 } else { 1478 /* RFC 2960 6.1, sctpimpguide-06 2.15.2 1479 * When a sender is doing zero window probing, it 1480 * should not timeout the association if it continues 1481 * to receive new packets from the receiver. The 1482 * reason is that the receiver MAY keep its window 1483 * closed for an indefinite time. 1484 * A sender is doing zero window probing when the 1485 * receiver's advertised window is zero, and there is 1486 * only one data chunk in flight to the receiver. 1487 */ 1488 if (!q->asoc->peer.rwnd && 1489 !list_empty(&tlist) && 1490 (sack_ctsn+2 == q->asoc->next_tsn)) { 1491 SCTP_DEBUG_PRINTK("%s: SACK received for zero " 1492 "window probe: %u\n", 1493 __FUNCTION__, sack_ctsn); 1494 q->asoc->overall_error_count = 0; 1495 transport->error_count = 0; 1496 } 1497 } 1498 1499 /* RFC 2960 6.3.2 Retransmission Timer Rules 1500 * 1501 * R2) Whenever all outstanding data sent to an address have 1502 * been acknowledged, turn off the T3-rtx timer of that 1503 * address. 1504 */ 1505 if (!transport->flight_size) { 1506 if (timer_pending(&transport->T3_rtx_timer) && 1507 del_timer(&transport->T3_rtx_timer)) { 1508 sctp_transport_put(transport); 1509 } 1510 } else if (restart_timer) { 1511 if (!mod_timer(&transport->T3_rtx_timer, 1512 jiffies + transport->rto)) 1513 sctp_transport_hold(transport); 1514 } 1515 } 1516 1517 list_splice(&tlist, transmitted_queue); 1518 } 1519 1520 /* Mark chunks as missing and consequently may get retransmitted. */ 1521 static void sctp_mark_missing(struct sctp_outq *q, 1522 struct list_head *transmitted_queue, 1523 struct sctp_transport *transport, 1524 __u32 highest_new_tsn_in_sack, 1525 int count_of_newacks) 1526 { 1527 struct sctp_chunk *chunk; 1528 struct list_head *pos; 1529 __u32 tsn; 1530 char do_fast_retransmit = 0; 1531 struct sctp_transport *primary = q->asoc->peer.primary_path; 1532 1533 list_for_each(pos, transmitted_queue) { 1534 1535 chunk = list_entry(pos, struct sctp_chunk, transmitted_list); 1536 tsn = ntohl(chunk->subh.data_hdr->tsn); 1537 1538 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all 1539 * 'Unacknowledged TSN's', if the TSN number of an 1540 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack' 1541 * value, increment the 'TSN.Missing.Report' count on that 1542 * chunk if it has NOT been fast retransmitted or marked for 1543 * fast retransmit already. 1544 */ 1545 if (!chunk->fast_retransmit && 1546 !chunk->tsn_gap_acked && 1547 TSN_lt(tsn, highest_new_tsn_in_sack)) { 1548 1549 /* SFR-CACC may require us to skip marking 1550 * this chunk as missing. 1551 */ 1552 if (!transport || !sctp_cacc_skip(primary, transport, 1553 count_of_newacks, tsn)) { 1554 chunk->tsn_missing_report++; 1555 1556 SCTP_DEBUG_PRINTK( 1557 "%s: TSN 0x%x missing counter: %d\n", 1558 __FUNCTION__, tsn, 1559 chunk->tsn_missing_report); 1560 } 1561 } 1562 /* 1563 * M4) If any DATA chunk is found to have a 1564 * 'TSN.Missing.Report' 1565 * value larger than or equal to 4, mark that chunk for 1566 * retransmission and start the fast retransmit procedure. 1567 */ 1568 1569 if (chunk->tsn_missing_report >= 4) { 1570 chunk->fast_retransmit = 1; 1571 do_fast_retransmit = 1; 1572 } 1573 } 1574 1575 if (transport) { 1576 if (do_fast_retransmit) 1577 sctp_retransmit(q, transport, SCTP_RTXR_FAST_RTX); 1578 1579 SCTP_DEBUG_PRINTK("%s: transport: %p, cwnd: %d, " 1580 "ssthresh: %d, flight_size: %d, pba: %d\n", 1581 __FUNCTION__, transport, transport->cwnd, 1582 transport->ssthresh, transport->flight_size, 1583 transport->partial_bytes_acked); 1584 } 1585 } 1586 1587 /* Is the given TSN acked by this packet? */ 1588 static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn) 1589 { 1590 int i; 1591 sctp_sack_variable_t *frags; 1592 __u16 gap; 1593 __u32 ctsn = ntohl(sack->cum_tsn_ack); 1594 1595 if (TSN_lte(tsn, ctsn)) 1596 goto pass; 1597 1598 /* 3.3.4 Selective Acknowledgement (SACK) (3): 1599 * 1600 * Gap Ack Blocks: 1601 * These fields contain the Gap Ack Blocks. They are repeated 1602 * for each Gap Ack Block up to the number of Gap Ack Blocks 1603 * defined in the Number of Gap Ack Blocks field. All DATA 1604 * chunks with TSNs greater than or equal to (Cumulative TSN 1605 * Ack + Gap Ack Block Start) and less than or equal to 1606 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack 1607 * Block are assumed to have been received correctly. 1608 */ 1609 1610 frags = sack->variable; 1611 gap = tsn - ctsn; 1612 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); ++i) { 1613 if (TSN_lte(ntohs(frags[i].gab.start), gap) && 1614 TSN_lte(gap, ntohs(frags[i].gab.end))) 1615 goto pass; 1616 } 1617 1618 return 0; 1619 pass: 1620 return 1; 1621 } 1622 1623 static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip *skiplist, 1624 int nskips, __u16 stream) 1625 { 1626 int i; 1627 1628 for (i = 0; i < nskips; i++) { 1629 if (skiplist[i].stream == stream) 1630 return i; 1631 } 1632 return i; 1633 } 1634 1635 /* Create and add a fwdtsn chunk to the outq's control queue if needed. */ 1636 static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 ctsn) 1637 { 1638 struct sctp_association *asoc = q->asoc; 1639 struct sctp_chunk *ftsn_chunk = NULL; 1640 struct sctp_fwdtsn_skip ftsn_skip_arr[10]; 1641 int nskips = 0; 1642 int skip_pos = 0; 1643 __u32 tsn; 1644 struct sctp_chunk *chunk; 1645 struct list_head *lchunk, *temp; 1646 1647 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the 1648 * received SACK. 1649 * 1650 * If (Advanced.Peer.Ack.Point < SackCumAck), then update 1651 * Advanced.Peer.Ack.Point to be equal to SackCumAck. 1652 */ 1653 if (TSN_lt(asoc->adv_peer_ack_point, ctsn)) 1654 asoc->adv_peer_ack_point = ctsn; 1655 1656 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point" 1657 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as 1658 * the chunk next in the out-queue space is marked as "abandoned" as 1659 * shown in the following example: 1660 * 1661 * Assuming that a SACK arrived with the Cumulative TSN ACK 102 1662 * and the Advanced.Peer.Ack.Point is updated to this value: 1663 * 1664 * out-queue at the end of ==> out-queue after Adv.Ack.Point 1665 * normal SACK processing local advancement 1666 * ... ... 1667 * Adv.Ack.Pt-> 102 acked 102 acked 1668 * 103 abandoned 103 abandoned 1669 * 104 abandoned Adv.Ack.P-> 104 abandoned 1670 * 105 105 1671 * 106 acked 106 acked 1672 * ... ... 1673 * 1674 * In this example, the data sender successfully advanced the 1675 * "Advanced.Peer.Ack.Point" from 102 to 104 locally. 1676 */ 1677 list_for_each_safe(lchunk, temp, &q->abandoned) { 1678 chunk = list_entry(lchunk, struct sctp_chunk, 1679 transmitted_list); 1680 tsn = ntohl(chunk->subh.data_hdr->tsn); 1681 1682 /* Remove any chunks in the abandoned queue that are acked by 1683 * the ctsn. 1684 */ 1685 if (TSN_lte(tsn, ctsn)) { 1686 list_del_init(lchunk); 1687 if (!chunk->tsn_gap_acked) { 1688 chunk->transport->flight_size -= 1689 sctp_data_size(chunk); 1690 q->outstanding_bytes -= sctp_data_size(chunk); 1691 } 1692 sctp_chunk_free(chunk); 1693 } else { 1694 if (TSN_lte(tsn, asoc->adv_peer_ack_point+1)) { 1695 asoc->adv_peer_ack_point = tsn; 1696 if (chunk->chunk_hdr->flags & 1697 SCTP_DATA_UNORDERED) 1698 continue; 1699 skip_pos = sctp_get_skip_pos(&ftsn_skip_arr[0], 1700 nskips, 1701 chunk->subh.data_hdr->stream); 1702 ftsn_skip_arr[skip_pos].stream = 1703 chunk->subh.data_hdr->stream; 1704 ftsn_skip_arr[skip_pos].ssn = 1705 chunk->subh.data_hdr->ssn; 1706 if (skip_pos == nskips) 1707 nskips++; 1708 if (nskips == 10) 1709 break; 1710 } else 1711 break; 1712 } 1713 } 1714 1715 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point" 1716 * is greater than the Cumulative TSN ACK carried in the received 1717 * SACK, the data sender MUST send the data receiver a FORWARD TSN 1718 * chunk containing the latest value of the 1719 * "Advanced.Peer.Ack.Point". 1720 * 1721 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD 1722 * list each stream and sequence number in the forwarded TSN. This 1723 * information will enable the receiver to easily find any 1724 * stranded TSN's waiting on stream reorder queues. Each stream 1725 * SHOULD only be reported once; this means that if multiple 1726 * abandoned messages occur in the same stream then only the 1727 * highest abandoned stream sequence number is reported. If the 1728 * total size of the FORWARD TSN does NOT fit in a single MTU then 1729 * the sender of the FORWARD TSN SHOULD lower the 1730 * Advanced.Peer.Ack.Point to the last TSN that will fit in a 1731 * single MTU. 1732 */ 1733 if (asoc->adv_peer_ack_point > ctsn) 1734 ftsn_chunk = sctp_make_fwdtsn(asoc, asoc->adv_peer_ack_point, 1735 nskips, &ftsn_skip_arr[0]); 1736 1737 if (ftsn_chunk) { 1738 list_add_tail(&ftsn_chunk->list, &q->control_chunk_list); 1739 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 1740 } 1741 } 1742