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 > 0)) || 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 if (chunk->fast_retransmit > 0) 607 chunk->fast_retransmit = -1; 608 609 *start_timer = 1; 610 q->empty = 0; 611 612 /* Retrieve a new chunk to bundle. */ 613 lchunk = sctp_list_dequeue(lqueue); 614 break; 615 }; 616 617 /* If we are here due to a retransmit timeout or a fast 618 * retransmit and if there are any chunks left in the retransmit 619 * queue that could not fit in the PMTU sized packet, they need * to be marked as ineligible for a subsequent fast retransmit. 620 */ 621 if (rtx_timeout && !lchunk) { 622 list_for_each(lchunk1, lqueue) { 623 chunk1 = list_entry(lchunk1, struct sctp_chunk, 624 transmitted_list); 625 if (chunk1->fast_retransmit > 0) 626 chunk1->fast_retransmit = -1; 627 } 628 } 629 } 630 631 return error; 632 } 633 634 /* Cork the outqueue so queued chunks are really queued. */ 635 int sctp_outq_uncork(struct sctp_outq *q) 636 { 637 int error = 0; 638 if (q->cork) { 639 q->cork = 0; 640 error = sctp_outq_flush(q, 0); 641 } 642 return error; 643 } 644 645 /* 646 * Try to flush an outqueue. 647 * 648 * Description: Send everything in q which we legally can, subject to 649 * congestion limitations. 650 * * Note: This function can be called from multiple contexts so appropriate 651 * locking concerns must be made. Today we use the sock lock to protect 652 * this function. 653 */ 654 int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout) 655 { 656 struct sctp_packet *packet; 657 struct sctp_packet singleton; 658 struct sctp_association *asoc = q->asoc; 659 __u16 sport = asoc->base.bind_addr.port; 660 __u16 dport = asoc->peer.port; 661 __u32 vtag = asoc->peer.i.init_tag; 662 struct sctp_transport *transport = NULL; 663 struct sctp_transport *new_transport; 664 struct sctp_chunk *chunk, *tmp; 665 sctp_xmit_t status; 666 int error = 0; 667 int start_timer = 0; 668 669 /* These transports have chunks to send. */ 670 struct list_head transport_list; 671 struct list_head *ltransport; 672 673 INIT_LIST_HEAD(&transport_list); 674 packet = NULL; 675 676 /* 677 * 6.10 Bundling 678 * ... 679 * When bundling control chunks with DATA chunks, an 680 * endpoint MUST place control chunks first in the outbound 681 * SCTP packet. The transmitter MUST transmit DATA chunks 682 * within a SCTP packet in increasing order of TSN. 683 * ... 684 */ 685 686 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) { 687 list_del_init(&chunk->list); 688 689 /* Pick the right transport to use. */ 690 new_transport = chunk->transport; 691 692 if (!new_transport) { 693 new_transport = asoc->peer.active_path; 694 } else if ((new_transport->state == SCTP_INACTIVE) || 695 (new_transport->state == SCTP_UNCONFIRMED)) { 696 /* If the chunk is Heartbeat or Heartbeat Ack, 697 * send it to chunk->transport, even if it's 698 * inactive. 699 * 700 * 3.3.6 Heartbeat Acknowledgement: 701 * ... 702 * A HEARTBEAT ACK is always sent to the source IP 703 * address of the IP datagram containing the 704 * HEARTBEAT chunk to which this ack is responding. 705 * ... 706 */ 707 if (chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT && 708 chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT_ACK) 709 new_transport = asoc->peer.active_path; 710 } 711 712 /* Are we switching transports? 713 * Take care of transport locks. 714 */ 715 if (new_transport != transport) { 716 transport = new_transport; 717 if (list_empty(&transport->send_ready)) { 718 list_add_tail(&transport->send_ready, 719 &transport_list); 720 } 721 packet = &transport->packet; 722 sctp_packet_config(packet, vtag, 723 asoc->peer.ecn_capable); 724 } 725 726 switch (chunk->chunk_hdr->type) { 727 /* 728 * 6.10 Bundling 729 * ... 730 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN 731 * COMPLETE with any other chunks. [Send them immediately.] 732 */ 733 case SCTP_CID_INIT: 734 case SCTP_CID_INIT_ACK: 735 case SCTP_CID_SHUTDOWN_COMPLETE: 736 sctp_packet_init(&singleton, transport, sport, dport); 737 sctp_packet_config(&singleton, vtag, 0); 738 sctp_packet_append_chunk(&singleton, chunk); 739 error = sctp_packet_transmit(&singleton); 740 if (error < 0) 741 return error; 742 break; 743 744 case SCTP_CID_ABORT: 745 case SCTP_CID_SACK: 746 case SCTP_CID_HEARTBEAT: 747 case SCTP_CID_HEARTBEAT_ACK: 748 case SCTP_CID_SHUTDOWN: 749 case SCTP_CID_SHUTDOWN_ACK: 750 case SCTP_CID_ERROR: 751 case SCTP_CID_COOKIE_ECHO: 752 case SCTP_CID_COOKIE_ACK: 753 case SCTP_CID_ECN_ECNE: 754 case SCTP_CID_ECN_CWR: 755 case SCTP_CID_ASCONF: 756 case SCTP_CID_ASCONF_ACK: 757 case SCTP_CID_FWD_TSN: 758 sctp_packet_transmit_chunk(packet, chunk); 759 break; 760 761 default: 762 /* We built a chunk with an illegal type! */ 763 BUG(); 764 }; 765 } 766 767 /* Is it OK to send data chunks? */ 768 switch (asoc->state) { 769 case SCTP_STATE_COOKIE_ECHOED: 770 /* Only allow bundling when this packet has a COOKIE-ECHO 771 * chunk. 772 */ 773 if (!packet || !packet->has_cookie_echo) 774 break; 775 776 /* fallthru */ 777 case SCTP_STATE_ESTABLISHED: 778 case SCTP_STATE_SHUTDOWN_PENDING: 779 case SCTP_STATE_SHUTDOWN_RECEIVED: 780 /* 781 * RFC 2960 6.1 Transmission of DATA Chunks 782 * 783 * C) When the time comes for the sender to transmit, 784 * before sending new DATA chunks, the sender MUST 785 * first transmit any outstanding DATA chunks which 786 * are marked for retransmission (limited by the 787 * current cwnd). 788 */ 789 if (!list_empty(&q->retransmit)) { 790 if (transport == asoc->peer.retran_path) 791 goto retran; 792 793 /* Switch transports & prepare the packet. */ 794 795 transport = asoc->peer.retran_path; 796 797 if (list_empty(&transport->send_ready)) { 798 list_add_tail(&transport->send_ready, 799 &transport_list); 800 } 801 802 packet = &transport->packet; 803 sctp_packet_config(packet, vtag, 804 asoc->peer.ecn_capable); 805 retran: 806 error = sctp_outq_flush_rtx(q, packet, 807 rtx_timeout, &start_timer); 808 809 if (start_timer) 810 sctp_transport_reset_timers(transport); 811 812 /* This can happen on COOKIE-ECHO resend. Only 813 * one chunk can get bundled with a COOKIE-ECHO. 814 */ 815 if (packet->has_cookie_echo) 816 goto sctp_flush_out; 817 818 /* Don't send new data if there is still data 819 * waiting to retransmit. 820 */ 821 if (!list_empty(&q->retransmit)) 822 goto sctp_flush_out; 823 } 824 825 /* Finally, transmit new packets. */ 826 start_timer = 0; 827 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) { 828 /* RFC 2960 6.5 Every DATA chunk MUST carry a valid 829 * stream identifier. 830 */ 831 if (chunk->sinfo.sinfo_stream >= 832 asoc->c.sinit_num_ostreams) { 833 834 /* Mark as failed send. */ 835 sctp_chunk_fail(chunk, SCTP_ERROR_INV_STRM); 836 sctp_chunk_free(chunk); 837 continue; 838 } 839 840 /* Has this chunk expired? */ 841 if (sctp_chunk_abandoned(chunk)) { 842 sctp_chunk_fail(chunk, 0); 843 sctp_chunk_free(chunk); 844 continue; 845 } 846 847 /* If there is a specified transport, use it. 848 * Otherwise, we want to use the active path. 849 */ 850 new_transport = chunk->transport; 851 if (!new_transport || 852 ((new_transport->state == SCTP_INACTIVE) || 853 (new_transport->state == SCTP_UNCONFIRMED))) 854 new_transport = asoc->peer.active_path; 855 856 /* Change packets if necessary. */ 857 if (new_transport != transport) { 858 transport = new_transport; 859 860 /* Schedule to have this transport's 861 * packet flushed. 862 */ 863 if (list_empty(&transport->send_ready)) { 864 list_add_tail(&transport->send_ready, 865 &transport_list); 866 } 867 868 packet = &transport->packet; 869 sctp_packet_config(packet, vtag, 870 asoc->peer.ecn_capable); 871 } 872 873 SCTP_DEBUG_PRINTK("sctp_outq_flush(%p, %p[%s]), ", 874 q, chunk, 875 chunk && chunk->chunk_hdr ? 876 sctp_cname(SCTP_ST_CHUNK( 877 chunk->chunk_hdr->type)) 878 : "Illegal Chunk"); 879 880 SCTP_DEBUG_PRINTK("TX TSN 0x%x skb->head " 881 "%p skb->users %d.\n", 882 ntohl(chunk->subh.data_hdr->tsn), 883 chunk->skb ?chunk->skb->head : NULL, 884 chunk->skb ? 885 atomic_read(&chunk->skb->users) : -1); 886 887 /* Add the chunk to the packet. */ 888 status = sctp_packet_transmit_chunk(packet, chunk); 889 890 switch (status) { 891 case SCTP_XMIT_PMTU_FULL: 892 case SCTP_XMIT_RWND_FULL: 893 case SCTP_XMIT_NAGLE_DELAY: 894 /* We could not append this chunk, so put 895 * the chunk back on the output queue. 896 */ 897 SCTP_DEBUG_PRINTK("sctp_outq_flush: could " 898 "not transmit TSN: 0x%x, status: %d\n", 899 ntohl(chunk->subh.data_hdr->tsn), 900 status); 901 sctp_outq_head_data(q, chunk); 902 goto sctp_flush_out; 903 break; 904 905 case SCTP_XMIT_OK: 906 break; 907 908 default: 909 BUG(); 910 } 911 912 /* BUG: We assume that the sctp_packet_transmit() 913 * call below will succeed all the time and add the 914 * chunk to the transmitted list and restart the 915 * timers. 916 * It is possible that the call can fail under OOM 917 * conditions. 918 * 919 * Is this really a problem? Won't this behave 920 * like a lost TSN? 921 */ 922 list_add_tail(&chunk->transmitted_list, 923 &transport->transmitted); 924 925 sctp_transport_reset_timers(transport); 926 927 q->empty = 0; 928 929 /* Only let one DATA chunk get bundled with a 930 * COOKIE-ECHO chunk. 931 */ 932 if (packet->has_cookie_echo) 933 goto sctp_flush_out; 934 } 935 break; 936 937 default: 938 /* Do nothing. */ 939 break; 940 } 941 942 sctp_flush_out: 943 944 /* Before returning, examine all the transports touched in 945 * this call. Right now, we bluntly force clear all the 946 * transports. Things might change after we implement Nagle. 947 * But such an examination is still required. 948 * 949 * --xguo 950 */ 951 while ((ltransport = sctp_list_dequeue(&transport_list)) != NULL ) { 952 struct sctp_transport *t = list_entry(ltransport, 953 struct sctp_transport, 954 send_ready); 955 packet = &t->packet; 956 if (!sctp_packet_empty(packet)) 957 error = sctp_packet_transmit(packet); 958 } 959 960 return error; 961 } 962 963 /* Update unack_data based on the incoming SACK chunk */ 964 static void sctp_sack_update_unack_data(struct sctp_association *assoc, 965 struct sctp_sackhdr *sack) 966 { 967 sctp_sack_variable_t *frags; 968 __u16 unack_data; 969 int i; 970 971 unack_data = assoc->next_tsn - assoc->ctsn_ack_point - 1; 972 973 frags = sack->variable; 974 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); i++) { 975 unack_data -= ((ntohs(frags[i].gab.end) - 976 ntohs(frags[i].gab.start) + 1)); 977 } 978 979 assoc->unack_data = unack_data; 980 } 981 982 /* Return the highest new tsn that is acknowledged by the given SACK chunk. */ 983 static __u32 sctp_highest_new_tsn(struct sctp_sackhdr *sack, 984 struct sctp_association *asoc) 985 { 986 struct list_head *ltransport, *lchunk; 987 struct sctp_transport *transport; 988 struct sctp_chunk *chunk; 989 __u32 highest_new_tsn, tsn; 990 struct list_head *transport_list = &asoc->peer.transport_addr_list; 991 992 highest_new_tsn = ntohl(sack->cum_tsn_ack); 993 994 list_for_each(ltransport, transport_list) { 995 transport = list_entry(ltransport, struct sctp_transport, 996 transports); 997 list_for_each(lchunk, &transport->transmitted) { 998 chunk = list_entry(lchunk, struct sctp_chunk, 999 transmitted_list); 1000 tsn = ntohl(chunk->subh.data_hdr->tsn); 1001 1002 if (!chunk->tsn_gap_acked && 1003 TSN_lt(highest_new_tsn, tsn) && 1004 sctp_acked(sack, tsn)) 1005 highest_new_tsn = tsn; 1006 } 1007 } 1008 1009 return highest_new_tsn; 1010 } 1011 1012 /* This is where we REALLY process a SACK. 1013 * 1014 * Process the SACK against the outqueue. Mostly, this just frees 1015 * things off the transmitted queue. 1016 */ 1017 int sctp_outq_sack(struct sctp_outq *q, struct sctp_sackhdr *sack) 1018 { 1019 struct sctp_association *asoc = q->asoc; 1020 struct sctp_transport *transport; 1021 struct sctp_chunk *tchunk = NULL; 1022 struct list_head *lchunk, *transport_list, *pos, *temp; 1023 sctp_sack_variable_t *frags = sack->variable; 1024 __u32 sack_ctsn, ctsn, tsn; 1025 __u32 highest_tsn, highest_new_tsn; 1026 __u32 sack_a_rwnd; 1027 unsigned outstanding; 1028 struct sctp_transport *primary = asoc->peer.primary_path; 1029 int count_of_newacks = 0; 1030 1031 /* Grab the association's destination address list. */ 1032 transport_list = &asoc->peer.transport_addr_list; 1033 1034 sack_ctsn = ntohl(sack->cum_tsn_ack); 1035 1036 /* 1037 * SFR-CACC algorithm: 1038 * On receipt of a SACK the sender SHOULD execute the 1039 * following statements. 1040 * 1041 * 1) If the cumulative ack in the SACK passes next tsn_at_change 1042 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be 1043 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for 1044 * all destinations. 1045 */ 1046 if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) { 1047 primary->cacc.changeover_active = 0; 1048 list_for_each(pos, transport_list) { 1049 transport = list_entry(pos, struct sctp_transport, 1050 transports); 1051 transport->cacc.cycling_changeover = 0; 1052 } 1053 } 1054 1055 /* 1056 * SFR-CACC algorithm: 1057 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE 1058 * is set the receiver of the SACK MUST take the following actions: 1059 * 1060 * A) Initialize the cacc_saw_newack to 0 for all destination 1061 * addresses. 1062 */ 1063 if (sack->num_gap_ack_blocks > 0 && 1064 primary->cacc.changeover_active) { 1065 list_for_each(pos, transport_list) { 1066 transport = list_entry(pos, struct sctp_transport, 1067 transports); 1068 transport->cacc.cacc_saw_newack = 0; 1069 } 1070 } 1071 1072 /* Get the highest TSN in the sack. */ 1073 highest_tsn = sack_ctsn; 1074 if (sack->num_gap_ack_blocks) 1075 highest_tsn += 1076 ntohs(frags[ntohs(sack->num_gap_ack_blocks) - 1].gab.end); 1077 1078 if (TSN_lt(asoc->highest_sacked, highest_tsn)) { 1079 highest_new_tsn = highest_tsn; 1080 asoc->highest_sacked = highest_tsn; 1081 } else { 1082 highest_new_tsn = sctp_highest_new_tsn(sack, asoc); 1083 } 1084 1085 /* Run through the retransmit queue. Credit bytes received 1086 * and free those chunks that we can. 1087 */ 1088 sctp_check_transmitted(q, &q->retransmit, NULL, sack, highest_new_tsn); 1089 sctp_mark_missing(q, &q->retransmit, NULL, highest_new_tsn, 0); 1090 1091 /* Run through the transmitted queue. 1092 * Credit bytes received and free those chunks which we can. 1093 * 1094 * This is a MASSIVE candidate for optimization. 1095 */ 1096 list_for_each(pos, transport_list) { 1097 transport = list_entry(pos, struct sctp_transport, 1098 transports); 1099 sctp_check_transmitted(q, &transport->transmitted, 1100 transport, sack, highest_new_tsn); 1101 /* 1102 * SFR-CACC algorithm: 1103 * C) Let count_of_newacks be the number of 1104 * destinations for which cacc_saw_newack is set. 1105 */ 1106 if (transport->cacc.cacc_saw_newack) 1107 count_of_newacks ++; 1108 } 1109 1110 list_for_each(pos, transport_list) { 1111 transport = list_entry(pos, struct sctp_transport, 1112 transports); 1113 sctp_mark_missing(q, &transport->transmitted, transport, 1114 highest_new_tsn, count_of_newacks); 1115 } 1116 1117 /* Move the Cumulative TSN Ack Point if appropriate. */ 1118 if (TSN_lt(asoc->ctsn_ack_point, sack_ctsn)) 1119 asoc->ctsn_ack_point = sack_ctsn; 1120 1121 /* Update unack_data field in the assoc. */ 1122 sctp_sack_update_unack_data(asoc, sack); 1123 1124 ctsn = asoc->ctsn_ack_point; 1125 1126 /* Throw away stuff rotting on the sack queue. */ 1127 list_for_each_safe(lchunk, temp, &q->sacked) { 1128 tchunk = list_entry(lchunk, struct sctp_chunk, 1129 transmitted_list); 1130 tsn = ntohl(tchunk->subh.data_hdr->tsn); 1131 if (TSN_lte(tsn, ctsn)) 1132 sctp_chunk_free(tchunk); 1133 } 1134 1135 /* ii) Set rwnd equal to the newly received a_rwnd minus the 1136 * number of bytes still outstanding after processing the 1137 * Cumulative TSN Ack and the Gap Ack Blocks. 1138 */ 1139 1140 sack_a_rwnd = ntohl(sack->a_rwnd); 1141 outstanding = q->outstanding_bytes; 1142 1143 if (outstanding < sack_a_rwnd) 1144 sack_a_rwnd -= outstanding; 1145 else 1146 sack_a_rwnd = 0; 1147 1148 asoc->peer.rwnd = sack_a_rwnd; 1149 1150 sctp_generate_fwdtsn(q, sack_ctsn); 1151 1152 SCTP_DEBUG_PRINTK("%s: sack Cumulative TSN Ack is 0x%x.\n", 1153 __FUNCTION__, sack_ctsn); 1154 SCTP_DEBUG_PRINTK("%s: Cumulative TSN Ack of association, " 1155 "%p is 0x%x. Adv peer ack point: 0x%x\n", 1156 __FUNCTION__, asoc, ctsn, asoc->adv_peer_ack_point); 1157 1158 /* See if all chunks are acked. 1159 * Make sure the empty queue handler will get run later. 1160 */ 1161 q->empty = (list_empty(&q->out_chunk_list) && 1162 list_empty(&q->control_chunk_list) && 1163 list_empty(&q->retransmit)); 1164 if (!q->empty) 1165 goto finish; 1166 1167 list_for_each(pos, transport_list) { 1168 transport = list_entry(pos, struct sctp_transport, 1169 transports); 1170 q->empty = q->empty && list_empty(&transport->transmitted); 1171 if (!q->empty) 1172 goto finish; 1173 } 1174 1175 SCTP_DEBUG_PRINTK("sack queue is empty.\n"); 1176 finish: 1177 return q->empty; 1178 } 1179 1180 /* Is the outqueue empty? */ 1181 int sctp_outq_is_empty(const struct sctp_outq *q) 1182 { 1183 return q->empty; 1184 } 1185 1186 /******************************************************************** 1187 * 2nd Level Abstractions 1188 ********************************************************************/ 1189 1190 /* Go through a transport's transmitted list or the association's retransmit 1191 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked. 1192 * The retransmit list will not have an associated transport. 1193 * 1194 * I added coherent debug information output. --xguo 1195 * 1196 * Instead of printing 'sacked' or 'kept' for each TSN on the 1197 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5. 1198 * KEPT TSN6-TSN7, etc. 1199 */ 1200 static void sctp_check_transmitted(struct sctp_outq *q, 1201 struct list_head *transmitted_queue, 1202 struct sctp_transport *transport, 1203 struct sctp_sackhdr *sack, 1204 __u32 highest_new_tsn_in_sack) 1205 { 1206 struct list_head *lchunk; 1207 struct sctp_chunk *tchunk; 1208 struct list_head tlist; 1209 __u32 tsn; 1210 __u32 sack_ctsn; 1211 __u32 rtt; 1212 __u8 restart_timer = 0; 1213 int bytes_acked = 0; 1214 1215 /* These state variables are for coherent debug output. --xguo */ 1216 1217 #if SCTP_DEBUG 1218 __u32 dbg_ack_tsn = 0; /* An ACKed TSN range starts here... */ 1219 __u32 dbg_last_ack_tsn = 0; /* ...and finishes here. */ 1220 __u32 dbg_kept_tsn = 0; /* An un-ACKed range starts here... */ 1221 __u32 dbg_last_kept_tsn = 0; /* ...and finishes here. */ 1222 1223 /* 0 : The last TSN was ACKed. 1224 * 1 : The last TSN was NOT ACKed (i.e. KEPT). 1225 * -1: We need to initialize. 1226 */ 1227 int dbg_prt_state = -1; 1228 #endif /* SCTP_DEBUG */ 1229 1230 sack_ctsn = ntohl(sack->cum_tsn_ack); 1231 1232 INIT_LIST_HEAD(&tlist); 1233 1234 /* The while loop will skip empty transmitted queues. */ 1235 while (NULL != (lchunk = sctp_list_dequeue(transmitted_queue))) { 1236 tchunk = list_entry(lchunk, struct sctp_chunk, 1237 transmitted_list); 1238 1239 if (sctp_chunk_abandoned(tchunk)) { 1240 /* Move the chunk to abandoned list. */ 1241 sctp_insert_list(&q->abandoned, lchunk); 1242 continue; 1243 } 1244 1245 tsn = ntohl(tchunk->subh.data_hdr->tsn); 1246 if (sctp_acked(sack, tsn)) { 1247 /* If this queue is the retransmit queue, the 1248 * retransmit timer has already reclaimed 1249 * the outstanding bytes for this chunk, so only 1250 * count bytes associated with a transport. 1251 */ 1252 if (transport) { 1253 /* If this chunk is being used for RTT 1254 * measurement, calculate the RTT and update 1255 * the RTO using this value. 1256 * 1257 * 6.3.1 C5) Karn's algorithm: RTT measurements 1258 * MUST NOT be made using packets that were 1259 * retransmitted (and thus for which it is 1260 * ambiguous whether the reply was for the 1261 * first instance of the packet or a later 1262 * instance). 1263 */ 1264 if (!tchunk->tsn_gap_acked && 1265 !tchunk->resent && 1266 tchunk->rtt_in_progress) { 1267 tchunk->rtt_in_progress = 0; 1268 rtt = jiffies - tchunk->sent_at; 1269 sctp_transport_update_rto(transport, 1270 rtt); 1271 } 1272 } 1273 if (TSN_lte(tsn, sack_ctsn)) { 1274 /* RFC 2960 6.3.2 Retransmission Timer Rules 1275 * 1276 * R3) Whenever a SACK is received 1277 * that acknowledges the DATA chunk 1278 * with the earliest outstanding TSN 1279 * for that address, restart T3-rtx 1280 * timer for that address with its 1281 * current RTO. 1282 */ 1283 restart_timer = 1; 1284 1285 if (!tchunk->tsn_gap_acked) { 1286 tchunk->tsn_gap_acked = 1; 1287 bytes_acked += sctp_data_size(tchunk); 1288 /* 1289 * SFR-CACC algorithm: 1290 * 2) If the SACK contains gap acks 1291 * and the flag CHANGEOVER_ACTIVE is 1292 * set the receiver of the SACK MUST 1293 * take the following action: 1294 * 1295 * B) For each TSN t being acked that 1296 * has not been acked in any SACK so 1297 * far, set cacc_saw_newack to 1 for 1298 * the destination that the TSN was 1299 * sent to. 1300 */ 1301 if (transport && 1302 sack->num_gap_ack_blocks && 1303 q->asoc->peer.primary_path->cacc. 1304 changeover_active) 1305 transport->cacc.cacc_saw_newack 1306 = 1; 1307 } 1308 1309 list_add_tail(&tchunk->transmitted_list, 1310 &q->sacked); 1311 } else { 1312 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2 1313 * M2) Each time a SACK arrives reporting 1314 * 'Stray DATA chunk(s)' record the highest TSN 1315 * reported as newly acknowledged, call this 1316 * value 'HighestTSNinSack'. A newly 1317 * acknowledged DATA chunk is one not 1318 * previously acknowledged in a SACK. 1319 * 1320 * When the SCTP sender of data receives a SACK 1321 * chunk that acknowledges, for the first time, 1322 * the receipt of a DATA chunk, all the still 1323 * unacknowledged DATA chunks whose TSN is 1324 * older than that newly acknowledged DATA 1325 * chunk, are qualified as 'Stray DATA chunks'. 1326 */ 1327 if (!tchunk->tsn_gap_acked) { 1328 tchunk->tsn_gap_acked = 1; 1329 bytes_acked += sctp_data_size(tchunk); 1330 } 1331 list_add_tail(lchunk, &tlist); 1332 } 1333 1334 #if SCTP_DEBUG 1335 switch (dbg_prt_state) { 1336 case 0: /* last TSN was ACKed */ 1337 if (dbg_last_ack_tsn + 1 == tsn) { 1338 /* This TSN belongs to the 1339 * current ACK range. 1340 */ 1341 break; 1342 } 1343 1344 if (dbg_last_ack_tsn != dbg_ack_tsn) { 1345 /* Display the end of the 1346 * current range. 1347 */ 1348 SCTP_DEBUG_PRINTK("-%08x", 1349 dbg_last_ack_tsn); 1350 } 1351 1352 /* Start a new range. */ 1353 SCTP_DEBUG_PRINTK(",%08x", tsn); 1354 dbg_ack_tsn = tsn; 1355 break; 1356 1357 case 1: /* The last TSN was NOT ACKed. */ 1358 if (dbg_last_kept_tsn != dbg_kept_tsn) { 1359 /* Display the end of current range. */ 1360 SCTP_DEBUG_PRINTK("-%08x", 1361 dbg_last_kept_tsn); 1362 } 1363 1364 SCTP_DEBUG_PRINTK("\n"); 1365 1366 /* FALL THROUGH... */ 1367 default: 1368 /* This is the first-ever TSN we examined. */ 1369 /* Start a new range of ACK-ed TSNs. */ 1370 SCTP_DEBUG_PRINTK("ACKed: %08x", tsn); 1371 dbg_prt_state = 0; 1372 dbg_ack_tsn = tsn; 1373 }; 1374 1375 dbg_last_ack_tsn = tsn; 1376 #endif /* SCTP_DEBUG */ 1377 1378 } else { 1379 if (tchunk->tsn_gap_acked) { 1380 SCTP_DEBUG_PRINTK("%s: Receiver reneged on " 1381 "data TSN: 0x%x\n", 1382 __FUNCTION__, 1383 tsn); 1384 tchunk->tsn_gap_acked = 0; 1385 1386 bytes_acked -= sctp_data_size(tchunk); 1387 1388 /* RFC 2960 6.3.2 Retransmission Timer Rules 1389 * 1390 * R4) Whenever a SACK is received missing a 1391 * TSN that was previously acknowledged via a 1392 * Gap Ack Block, start T3-rtx for the 1393 * destination address to which the DATA 1394 * chunk was originally 1395 * transmitted if it is not already running. 1396 */ 1397 restart_timer = 1; 1398 } 1399 1400 list_add_tail(lchunk, &tlist); 1401 1402 #if SCTP_DEBUG 1403 /* See the above comments on ACK-ed TSNs. */ 1404 switch (dbg_prt_state) { 1405 case 1: 1406 if (dbg_last_kept_tsn + 1 == tsn) 1407 break; 1408 1409 if (dbg_last_kept_tsn != dbg_kept_tsn) 1410 SCTP_DEBUG_PRINTK("-%08x", 1411 dbg_last_kept_tsn); 1412 1413 SCTP_DEBUG_PRINTK(",%08x", tsn); 1414 dbg_kept_tsn = tsn; 1415 break; 1416 1417 case 0: 1418 if (dbg_last_ack_tsn != dbg_ack_tsn) 1419 SCTP_DEBUG_PRINTK("-%08x", 1420 dbg_last_ack_tsn); 1421 SCTP_DEBUG_PRINTK("\n"); 1422 1423 /* FALL THROUGH... */ 1424 default: 1425 SCTP_DEBUG_PRINTK("KEPT: %08x",tsn); 1426 dbg_prt_state = 1; 1427 dbg_kept_tsn = tsn; 1428 }; 1429 1430 dbg_last_kept_tsn = tsn; 1431 #endif /* SCTP_DEBUG */ 1432 } 1433 } 1434 1435 #if SCTP_DEBUG 1436 /* Finish off the last range, displaying its ending TSN. */ 1437 switch (dbg_prt_state) { 1438 case 0: 1439 if (dbg_last_ack_tsn != dbg_ack_tsn) { 1440 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_ack_tsn); 1441 } else { 1442 SCTP_DEBUG_PRINTK("\n"); 1443 } 1444 break; 1445 1446 case 1: 1447 if (dbg_last_kept_tsn != dbg_kept_tsn) { 1448 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_kept_tsn); 1449 } else { 1450 SCTP_DEBUG_PRINTK("\n"); 1451 } 1452 }; 1453 #endif /* SCTP_DEBUG */ 1454 if (transport) { 1455 if (bytes_acked) { 1456 /* 8.2. When an outstanding TSN is acknowledged, 1457 * the endpoint shall clear the error counter of 1458 * the destination transport address to which the 1459 * DATA chunk was last sent. 1460 * The association's overall error counter is 1461 * also cleared. 1462 */ 1463 transport->error_count = 0; 1464 transport->asoc->overall_error_count = 0; 1465 1466 /* Mark the destination transport address as 1467 * active if it is not so marked. 1468 */ 1469 if ((transport->state == SCTP_INACTIVE) || 1470 (transport->state == SCTP_UNCONFIRMED)) { 1471 sctp_assoc_control_transport( 1472 transport->asoc, 1473 transport, 1474 SCTP_TRANSPORT_UP, 1475 SCTP_RECEIVED_SACK); 1476 } 1477 1478 sctp_transport_raise_cwnd(transport, sack_ctsn, 1479 bytes_acked); 1480 1481 transport->flight_size -= bytes_acked; 1482 q->outstanding_bytes -= bytes_acked; 1483 } else { 1484 /* RFC 2960 6.1, sctpimpguide-06 2.15.2 1485 * When a sender is doing zero window probing, it 1486 * should not timeout the association if it continues 1487 * to receive new packets from the receiver. The 1488 * reason is that the receiver MAY keep its window 1489 * closed for an indefinite time. 1490 * A sender is doing zero window probing when the 1491 * receiver's advertised window is zero, and there is 1492 * only one data chunk in flight to the receiver. 1493 */ 1494 if (!q->asoc->peer.rwnd && 1495 !list_empty(&tlist) && 1496 (sack_ctsn+2 == q->asoc->next_tsn)) { 1497 SCTP_DEBUG_PRINTK("%s: SACK received for zero " 1498 "window probe: %u\n", 1499 __FUNCTION__, sack_ctsn); 1500 q->asoc->overall_error_count = 0; 1501 transport->error_count = 0; 1502 } 1503 } 1504 1505 /* RFC 2960 6.3.2 Retransmission Timer Rules 1506 * 1507 * R2) Whenever all outstanding data sent to an address have 1508 * been acknowledged, turn off the T3-rtx timer of that 1509 * address. 1510 */ 1511 if (!transport->flight_size) { 1512 if (timer_pending(&transport->T3_rtx_timer) && 1513 del_timer(&transport->T3_rtx_timer)) { 1514 sctp_transport_put(transport); 1515 } 1516 } else if (restart_timer) { 1517 if (!mod_timer(&transport->T3_rtx_timer, 1518 jiffies + transport->rto)) 1519 sctp_transport_hold(transport); 1520 } 1521 } 1522 1523 list_splice(&tlist, transmitted_queue); 1524 } 1525 1526 /* Mark chunks as missing and consequently may get retransmitted. */ 1527 static void sctp_mark_missing(struct sctp_outq *q, 1528 struct list_head *transmitted_queue, 1529 struct sctp_transport *transport, 1530 __u32 highest_new_tsn_in_sack, 1531 int count_of_newacks) 1532 { 1533 struct sctp_chunk *chunk; 1534 struct list_head *pos; 1535 __u32 tsn; 1536 char do_fast_retransmit = 0; 1537 struct sctp_transport *primary = q->asoc->peer.primary_path; 1538 1539 list_for_each(pos, transmitted_queue) { 1540 1541 chunk = list_entry(pos, struct sctp_chunk, transmitted_list); 1542 tsn = ntohl(chunk->subh.data_hdr->tsn); 1543 1544 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all 1545 * 'Unacknowledged TSN's', if the TSN number of an 1546 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack' 1547 * value, increment the 'TSN.Missing.Report' count on that 1548 * chunk if it has NOT been fast retransmitted or marked for 1549 * fast retransmit already. 1550 */ 1551 if (!chunk->fast_retransmit && 1552 !chunk->tsn_gap_acked && 1553 TSN_lt(tsn, highest_new_tsn_in_sack)) { 1554 1555 /* SFR-CACC may require us to skip marking 1556 * this chunk as missing. 1557 */ 1558 if (!transport || !sctp_cacc_skip(primary, transport, 1559 count_of_newacks, tsn)) { 1560 chunk->tsn_missing_report++; 1561 1562 SCTP_DEBUG_PRINTK( 1563 "%s: TSN 0x%x missing counter: %d\n", 1564 __FUNCTION__, tsn, 1565 chunk->tsn_missing_report); 1566 } 1567 } 1568 /* 1569 * M4) If any DATA chunk is found to have a 1570 * 'TSN.Missing.Report' 1571 * value larger than or equal to 3, mark that chunk for 1572 * retransmission and start the fast retransmit procedure. 1573 */ 1574 1575 if (chunk->tsn_missing_report >= 3) { 1576 chunk->fast_retransmit = 1; 1577 do_fast_retransmit = 1; 1578 } 1579 } 1580 1581 if (transport) { 1582 if (do_fast_retransmit) 1583 sctp_retransmit(q, transport, SCTP_RTXR_FAST_RTX); 1584 1585 SCTP_DEBUG_PRINTK("%s: transport: %p, cwnd: %d, " 1586 "ssthresh: %d, flight_size: %d, pba: %d\n", 1587 __FUNCTION__, transport, transport->cwnd, 1588 transport->ssthresh, transport->flight_size, 1589 transport->partial_bytes_acked); 1590 } 1591 } 1592 1593 /* Is the given TSN acked by this packet? */ 1594 static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn) 1595 { 1596 int i; 1597 sctp_sack_variable_t *frags; 1598 __u16 gap; 1599 __u32 ctsn = ntohl(sack->cum_tsn_ack); 1600 1601 if (TSN_lte(tsn, ctsn)) 1602 goto pass; 1603 1604 /* 3.3.4 Selective Acknowledgement (SACK) (3): 1605 * 1606 * Gap Ack Blocks: 1607 * These fields contain the Gap Ack Blocks. They are repeated 1608 * for each Gap Ack Block up to the number of Gap Ack Blocks 1609 * defined in the Number of Gap Ack Blocks field. All DATA 1610 * chunks with TSNs greater than or equal to (Cumulative TSN 1611 * Ack + Gap Ack Block Start) and less than or equal to 1612 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack 1613 * Block are assumed to have been received correctly. 1614 */ 1615 1616 frags = sack->variable; 1617 gap = tsn - ctsn; 1618 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); ++i) { 1619 if (TSN_lte(ntohs(frags[i].gab.start), gap) && 1620 TSN_lte(gap, ntohs(frags[i].gab.end))) 1621 goto pass; 1622 } 1623 1624 return 0; 1625 pass: 1626 return 1; 1627 } 1628 1629 static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip *skiplist, 1630 int nskips, __u16 stream) 1631 { 1632 int i; 1633 1634 for (i = 0; i < nskips; i++) { 1635 if (skiplist[i].stream == stream) 1636 return i; 1637 } 1638 return i; 1639 } 1640 1641 /* Create and add a fwdtsn chunk to the outq's control queue if needed. */ 1642 static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 ctsn) 1643 { 1644 struct sctp_association *asoc = q->asoc; 1645 struct sctp_chunk *ftsn_chunk = NULL; 1646 struct sctp_fwdtsn_skip ftsn_skip_arr[10]; 1647 int nskips = 0; 1648 int skip_pos = 0; 1649 __u32 tsn; 1650 struct sctp_chunk *chunk; 1651 struct list_head *lchunk, *temp; 1652 1653 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the 1654 * received SACK. 1655 * 1656 * If (Advanced.Peer.Ack.Point < SackCumAck), then update 1657 * Advanced.Peer.Ack.Point to be equal to SackCumAck. 1658 */ 1659 if (TSN_lt(asoc->adv_peer_ack_point, ctsn)) 1660 asoc->adv_peer_ack_point = ctsn; 1661 1662 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point" 1663 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as 1664 * the chunk next in the out-queue space is marked as "abandoned" as 1665 * shown in the following example: 1666 * 1667 * Assuming that a SACK arrived with the Cumulative TSN ACK 102 1668 * and the Advanced.Peer.Ack.Point is updated to this value: 1669 * 1670 * out-queue at the end of ==> out-queue after Adv.Ack.Point 1671 * normal SACK processing local advancement 1672 * ... ... 1673 * Adv.Ack.Pt-> 102 acked 102 acked 1674 * 103 abandoned 103 abandoned 1675 * 104 abandoned Adv.Ack.P-> 104 abandoned 1676 * 105 105 1677 * 106 acked 106 acked 1678 * ... ... 1679 * 1680 * In this example, the data sender successfully advanced the 1681 * "Advanced.Peer.Ack.Point" from 102 to 104 locally. 1682 */ 1683 list_for_each_safe(lchunk, temp, &q->abandoned) { 1684 chunk = list_entry(lchunk, struct sctp_chunk, 1685 transmitted_list); 1686 tsn = ntohl(chunk->subh.data_hdr->tsn); 1687 1688 /* Remove any chunks in the abandoned queue that are acked by 1689 * the ctsn. 1690 */ 1691 if (TSN_lte(tsn, ctsn)) { 1692 list_del_init(lchunk); 1693 if (!chunk->tsn_gap_acked) { 1694 chunk->transport->flight_size -= 1695 sctp_data_size(chunk); 1696 q->outstanding_bytes -= sctp_data_size(chunk); 1697 } 1698 sctp_chunk_free(chunk); 1699 } else { 1700 if (TSN_lte(tsn, asoc->adv_peer_ack_point+1)) { 1701 asoc->adv_peer_ack_point = tsn; 1702 if (chunk->chunk_hdr->flags & 1703 SCTP_DATA_UNORDERED) 1704 continue; 1705 skip_pos = sctp_get_skip_pos(&ftsn_skip_arr[0], 1706 nskips, 1707 chunk->subh.data_hdr->stream); 1708 ftsn_skip_arr[skip_pos].stream = 1709 chunk->subh.data_hdr->stream; 1710 ftsn_skip_arr[skip_pos].ssn = 1711 chunk->subh.data_hdr->ssn; 1712 if (skip_pos == nskips) 1713 nskips++; 1714 if (nskips == 10) 1715 break; 1716 } else 1717 break; 1718 } 1719 } 1720 1721 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point" 1722 * is greater than the Cumulative TSN ACK carried in the received 1723 * SACK, the data sender MUST send the data receiver a FORWARD TSN 1724 * chunk containing the latest value of the 1725 * "Advanced.Peer.Ack.Point". 1726 * 1727 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD 1728 * list each stream and sequence number in the forwarded TSN. This 1729 * information will enable the receiver to easily find any 1730 * stranded TSN's waiting on stream reorder queues. Each stream 1731 * SHOULD only be reported once; this means that if multiple 1732 * abandoned messages occur in the same stream then only the 1733 * highest abandoned stream sequence number is reported. If the 1734 * total size of the FORWARD TSN does NOT fit in a single MTU then 1735 * the sender of the FORWARD TSN SHOULD lower the 1736 * Advanced.Peer.Ack.Point to the last TSN that will fit in a 1737 * single MTU. 1738 */ 1739 if (asoc->adv_peer_ack_point > ctsn) 1740 ftsn_chunk = sctp_make_fwdtsn(asoc, asoc->adv_peer_ack_point, 1741 nskips, &ftsn_skip_arr[0]); 1742 1743 if (ftsn_chunk) { 1744 list_add_tail(&ftsn_chunk->list, &q->control_chunk_list); 1745 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 1746 } 1747 } 1748