1 /* SCTP kernel implementation 2 * (C) Copyright IBM Corp. 2001, 2004 3 * Copyright (c) 1999-2000 Cisco, Inc. 4 * Copyright (c) 1999-2001 Motorola, Inc. 5 * Copyright (c) 2001-2003 Intel Corp. 6 * 7 * This file is part of the SCTP kernel implementation 8 * 9 * These functions implement the sctp_outq class. The outqueue handles 10 * bundling and queueing of outgoing SCTP chunks. 11 * 12 * This SCTP implementation is free software; 13 * you can redistribute it and/or modify it under the terms of 14 * the GNU General Public License as published by 15 * the Free Software Foundation; either version 2, or (at your option) 16 * any later version. 17 * 18 * This SCTP implementation is distributed in the hope that it 19 * will be useful, but WITHOUT ANY WARRANTY; without even the implied 20 * ************************ 21 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 22 * See the GNU General Public License for more details. 23 * 24 * You should have received a copy of the GNU General Public License 25 * along with GNU CC; see the file COPYING. If not, write to 26 * the Free Software Foundation, 59 Temple Place - Suite 330, 27 * Boston, MA 02111-1307, USA. 28 * 29 * Please send any bug reports or fixes you make to the 30 * email address(es): 31 * lksctp developers <lksctp-developers@lists.sourceforge.net> 32 * 33 * Or submit a bug report through the following website: 34 * http://www.sf.net/projects/lksctp 35 * 36 * Written or modified by: 37 * La Monte H.P. Yarroll <piggy@acm.org> 38 * Karl Knutson <karl@athena.chicago.il.us> 39 * Perry Melange <pmelange@null.cc.uic.edu> 40 * Xingang Guo <xingang.guo@intel.com> 41 * Hui Huang <hui.huang@nokia.com> 42 * Sridhar Samudrala <sri@us.ibm.com> 43 * Jon Grimm <jgrimm@us.ibm.com> 44 * 45 * Any bugs reported given to us we will try to fix... any fixes shared will 46 * be incorporated into the next SCTP release. 47 */ 48 49 #include <linux/types.h> 50 #include <linux/list.h> /* For struct list_head */ 51 #include <linux/socket.h> 52 #include <linux/ip.h> 53 #include <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->fast_rtx = 0; 212 q->outstanding_bytes = 0; 213 q->empty = 1; 214 q->cork = 0; 215 216 q->malloced = 0; 217 q->out_qlen = 0; 218 } 219 220 /* Free the outqueue structure and any related pending chunks. 221 */ 222 void sctp_outq_teardown(struct sctp_outq *q) 223 { 224 struct sctp_transport *transport; 225 struct list_head *lchunk, *temp; 226 struct sctp_chunk *chunk, *tmp; 227 228 /* Throw away unacknowledged chunks. */ 229 list_for_each_entry(transport, &q->asoc->peer.transport_addr_list, 230 transports) { 231 while ((lchunk = sctp_list_dequeue(&transport->transmitted)) != NULL) { 232 chunk = list_entry(lchunk, struct sctp_chunk, 233 transmitted_list); 234 /* Mark as part of a failed message. */ 235 sctp_chunk_fail(chunk, q->error); 236 sctp_chunk_free(chunk); 237 } 238 } 239 240 /* Throw away chunks that have been gap ACKed. */ 241 list_for_each_safe(lchunk, temp, &q->sacked) { 242 list_del_init(lchunk); 243 chunk = list_entry(lchunk, struct sctp_chunk, 244 transmitted_list); 245 sctp_chunk_fail(chunk, q->error); 246 sctp_chunk_free(chunk); 247 } 248 249 /* Throw away any chunks in the retransmit queue. */ 250 list_for_each_safe(lchunk, temp, &q->retransmit) { 251 list_del_init(lchunk); 252 chunk = list_entry(lchunk, struct sctp_chunk, 253 transmitted_list); 254 sctp_chunk_fail(chunk, q->error); 255 sctp_chunk_free(chunk); 256 } 257 258 /* Throw away any chunks that are in the abandoned queue. */ 259 list_for_each_safe(lchunk, temp, &q->abandoned) { 260 list_del_init(lchunk); 261 chunk = list_entry(lchunk, struct sctp_chunk, 262 transmitted_list); 263 sctp_chunk_fail(chunk, q->error); 264 sctp_chunk_free(chunk); 265 } 266 267 /* Throw away any leftover data chunks. */ 268 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) { 269 270 /* Mark as send failure. */ 271 sctp_chunk_fail(chunk, q->error); 272 sctp_chunk_free(chunk); 273 } 274 275 q->error = 0; 276 277 /* Throw away any leftover control chunks. */ 278 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) { 279 list_del_init(&chunk->list); 280 sctp_chunk_free(chunk); 281 } 282 } 283 284 /* Free the outqueue structure and any related pending chunks. */ 285 void sctp_outq_free(struct sctp_outq *q) 286 { 287 /* Throw away leftover chunks. */ 288 sctp_outq_teardown(q); 289 290 /* If we were kmalloc()'d, free the memory. */ 291 if (q->malloced) 292 kfree(q); 293 } 294 295 /* Put a new chunk in an sctp_outq. */ 296 int sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk) 297 { 298 int error = 0; 299 300 SCTP_DEBUG_PRINTK("sctp_outq_tail(%p, %p[%s])\n", 301 q, chunk, chunk && chunk->chunk_hdr ? 302 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) 303 : "Illegal Chunk"); 304 305 /* If it is data, queue it up, otherwise, send it 306 * immediately. 307 */ 308 if (SCTP_CID_DATA == chunk->chunk_hdr->type) { 309 /* Is it OK to queue data chunks? */ 310 /* From 9. Termination of Association 311 * 312 * When either endpoint performs a shutdown, the 313 * association on each peer will stop accepting new 314 * data from its user and only deliver data in queue 315 * at the time of sending or receiving the SHUTDOWN 316 * chunk. 317 */ 318 switch (q->asoc->state) { 319 case SCTP_STATE_EMPTY: 320 case SCTP_STATE_CLOSED: 321 case SCTP_STATE_SHUTDOWN_PENDING: 322 case SCTP_STATE_SHUTDOWN_SENT: 323 case SCTP_STATE_SHUTDOWN_RECEIVED: 324 case SCTP_STATE_SHUTDOWN_ACK_SENT: 325 /* Cannot send after transport endpoint shutdown */ 326 error = -ESHUTDOWN; 327 break; 328 329 default: 330 SCTP_DEBUG_PRINTK("outqueueing (%p, %p[%s])\n", 331 q, chunk, chunk && chunk->chunk_hdr ? 332 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) 333 : "Illegal Chunk"); 334 335 sctp_outq_tail_data(q, chunk); 336 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) 337 SCTP_INC_STATS(SCTP_MIB_OUTUNORDERCHUNKS); 338 else 339 SCTP_INC_STATS(SCTP_MIB_OUTORDERCHUNKS); 340 q->empty = 0; 341 break; 342 } 343 } else { 344 list_add_tail(&chunk->list, &q->control_chunk_list); 345 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 346 } 347 348 if (error < 0) 349 return error; 350 351 if (!q->cork) 352 error = sctp_outq_flush(q, 0); 353 354 return error; 355 } 356 357 /* Insert a chunk into the sorted list based on the TSNs. The retransmit list 358 * and the abandoned list are in ascending order. 359 */ 360 static void sctp_insert_list(struct list_head *head, struct list_head *new) 361 { 362 struct list_head *pos; 363 struct sctp_chunk *nchunk, *lchunk; 364 __u32 ntsn, ltsn; 365 int done = 0; 366 367 nchunk = list_entry(new, struct sctp_chunk, transmitted_list); 368 ntsn = ntohl(nchunk->subh.data_hdr->tsn); 369 370 list_for_each(pos, head) { 371 lchunk = list_entry(pos, struct sctp_chunk, transmitted_list); 372 ltsn = ntohl(lchunk->subh.data_hdr->tsn); 373 if (TSN_lt(ntsn, ltsn)) { 374 list_add(new, pos->prev); 375 done = 1; 376 break; 377 } 378 } 379 if (!done) 380 list_add_tail(new, head); 381 } 382 383 /* Mark all the eligible packets on a transport for retransmission. */ 384 void sctp_retransmit_mark(struct sctp_outq *q, 385 struct sctp_transport *transport, 386 __u8 reason) 387 { 388 struct list_head *lchunk, *ltemp; 389 struct sctp_chunk *chunk; 390 391 /* Walk through the specified transmitted queue. */ 392 list_for_each_safe(lchunk, ltemp, &transport->transmitted) { 393 chunk = list_entry(lchunk, struct sctp_chunk, 394 transmitted_list); 395 396 /* If the chunk is abandoned, move it to abandoned list. */ 397 if (sctp_chunk_abandoned(chunk)) { 398 list_del_init(lchunk); 399 sctp_insert_list(&q->abandoned, lchunk); 400 401 /* If this chunk has not been previousely acked, 402 * stop considering it 'outstanding'. Our peer 403 * will most likely never see it since it will 404 * not be retransmitted 405 */ 406 if (!chunk->tsn_gap_acked) { 407 chunk->transport->flight_size -= 408 sctp_data_size(chunk); 409 q->outstanding_bytes -= sctp_data_size(chunk); 410 q->asoc->peer.rwnd += (sctp_data_size(chunk) + 411 sizeof(struct sk_buff)); 412 } 413 continue; 414 } 415 416 /* If we are doing retransmission due to a timeout or pmtu 417 * discovery, only the chunks that are not yet acked should 418 * be added to the retransmit queue. 419 */ 420 if ((reason == SCTP_RTXR_FAST_RTX && 421 (chunk->fast_retransmit > 0)) || 422 (reason != SCTP_RTXR_FAST_RTX && !chunk->tsn_gap_acked)) { 423 /* If this chunk was sent less then 1 rto ago, do not 424 * retransmit this chunk, but give the peer time 425 * to acknowlege it. Do this only when 426 * retransmitting due to T3 timeout. 427 */ 428 if (reason == SCTP_RTXR_T3_RTX && 429 (jiffies - chunk->sent_at) < transport->last_rto) 430 continue; 431 432 /* RFC 2960 6.2.1 Processing a Received SACK 433 * 434 * C) Any time a DATA chunk is marked for 435 * retransmission (via either T3-rtx timer expiration 436 * (Section 6.3.3) or via fast retransmit 437 * (Section 7.2.4)), add the data size of those 438 * chunks to the rwnd. 439 */ 440 q->asoc->peer.rwnd += (sctp_data_size(chunk) + 441 sizeof(struct sk_buff)); 442 q->outstanding_bytes -= sctp_data_size(chunk); 443 transport->flight_size -= sctp_data_size(chunk); 444 445 /* sctpimpguide-05 Section 2.8.2 446 * M5) If a T3-rtx timer expires, the 447 * 'TSN.Missing.Report' of all affected TSNs is set 448 * to 0. 449 */ 450 chunk->tsn_missing_report = 0; 451 452 /* If a chunk that is being used for RTT measurement 453 * has to be retransmitted, we cannot use this chunk 454 * anymore for RTT measurements. Reset rto_pending so 455 * that a new RTT measurement is started when a new 456 * data chunk is sent. 457 */ 458 if (chunk->rtt_in_progress) { 459 chunk->rtt_in_progress = 0; 460 transport->rto_pending = 0; 461 } 462 463 /* Move the chunk to the retransmit queue. The chunks 464 * on the retransmit queue are always kept in order. 465 */ 466 list_del_init(lchunk); 467 sctp_insert_list(&q->retransmit, lchunk); 468 } 469 } 470 471 SCTP_DEBUG_PRINTK("%s: transport: %p, reason: %d, " 472 "cwnd: %d, ssthresh: %d, flight_size: %d, " 473 "pba: %d\n", __func__, 474 transport, reason, 475 transport->cwnd, transport->ssthresh, 476 transport->flight_size, 477 transport->partial_bytes_acked); 478 479 } 480 481 /* Mark all the eligible packets on a transport for retransmission and force 482 * one packet out. 483 */ 484 void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport, 485 sctp_retransmit_reason_t reason) 486 { 487 int error = 0; 488 489 switch(reason) { 490 case SCTP_RTXR_T3_RTX: 491 SCTP_INC_STATS(SCTP_MIB_T3_RETRANSMITS); 492 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_T3_RTX); 493 /* Update the retran path if the T3-rtx timer has expired for 494 * the current retran path. 495 */ 496 if (transport == transport->asoc->peer.retran_path) 497 sctp_assoc_update_retran_path(transport->asoc); 498 transport->asoc->rtx_data_chunks += 499 transport->asoc->unack_data; 500 break; 501 case SCTP_RTXR_FAST_RTX: 502 SCTP_INC_STATS(SCTP_MIB_FAST_RETRANSMITS); 503 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_FAST_RTX); 504 q->fast_rtx = 1; 505 break; 506 case SCTP_RTXR_PMTUD: 507 SCTP_INC_STATS(SCTP_MIB_PMTUD_RETRANSMITS); 508 break; 509 case SCTP_RTXR_T1_RTX: 510 SCTP_INC_STATS(SCTP_MIB_T1_RETRANSMITS); 511 transport->asoc->init_retries++; 512 break; 513 default: 514 BUG(); 515 } 516 517 sctp_retransmit_mark(q, transport, reason); 518 519 /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination, 520 * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by 521 * following the procedures outlined in C1 - C5. 522 */ 523 if (reason == SCTP_RTXR_T3_RTX) 524 sctp_generate_fwdtsn(q, q->asoc->ctsn_ack_point); 525 526 /* Flush the queues only on timeout, since fast_rtx is only 527 * triggered during sack processing and the queue 528 * will be flushed at the end. 529 */ 530 if (reason != SCTP_RTXR_FAST_RTX) 531 error = sctp_outq_flush(q, /* rtx_timeout */ 1); 532 533 if (error) 534 q->asoc->base.sk->sk_err = -error; 535 } 536 537 /* 538 * Transmit DATA chunks on the retransmit queue. Upon return from 539 * sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which 540 * need to be transmitted by the caller. 541 * We assume that pkt->transport has already been set. 542 * 543 * The return value is a normal kernel error return value. 544 */ 545 static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt, 546 int rtx_timeout, int *start_timer) 547 { 548 struct list_head *lqueue; 549 struct sctp_transport *transport = pkt->transport; 550 sctp_xmit_t status; 551 struct sctp_chunk *chunk, *chunk1; 552 struct sctp_association *asoc; 553 int fast_rtx; 554 int error = 0; 555 int timer = 0; 556 int done = 0; 557 558 asoc = q->asoc; 559 lqueue = &q->retransmit; 560 fast_rtx = q->fast_rtx; 561 562 /* This loop handles time-out retransmissions, fast retransmissions, 563 * and retransmissions due to opening of whindow. 564 * 565 * RFC 2960 6.3.3 Handle T3-rtx Expiration 566 * 567 * E3) Determine how many of the earliest (i.e., lowest TSN) 568 * outstanding DATA chunks for the address for which the 569 * T3-rtx has expired will fit into a single packet, subject 570 * to the MTU constraint for the path corresponding to the 571 * destination transport address to which the retransmission 572 * is being sent (this may be different from the address for 573 * which the timer expires [see Section 6.4]). Call this value 574 * K. Bundle and retransmit those K DATA chunks in a single 575 * packet to the destination endpoint. 576 * 577 * [Just to be painfully clear, if we are retransmitting 578 * because a timeout just happened, we should send only ONE 579 * packet of retransmitted data.] 580 * 581 * For fast retransmissions we also send only ONE packet. However, 582 * if we are just flushing the queue due to open window, we'll 583 * try to send as much as possible. 584 */ 585 list_for_each_entry_safe(chunk, chunk1, lqueue, transmitted_list) { 586 587 /* Make sure that Gap Acked TSNs are not retransmitted. A 588 * simple approach is just to move such TSNs out of the 589 * way and into a 'transmitted' queue and skip to the 590 * next chunk. 591 */ 592 if (chunk->tsn_gap_acked) { 593 list_del(&chunk->transmitted_list); 594 list_add_tail(&chunk->transmitted_list, 595 &transport->transmitted); 596 continue; 597 } 598 599 /* If we are doing fast retransmit, ignore non-fast_rtransmit 600 * chunks 601 */ 602 if (fast_rtx && !chunk->fast_retransmit) 603 continue; 604 605 /* Attempt to append this chunk to the packet. */ 606 status = sctp_packet_append_chunk(pkt, chunk); 607 608 switch (status) { 609 case SCTP_XMIT_PMTU_FULL: 610 /* Send this packet. */ 611 error = sctp_packet_transmit(pkt); 612 613 /* If we are retransmitting, we should only 614 * send a single packet. 615 */ 616 if (rtx_timeout || fast_rtx) 617 done = 1; 618 619 /* Bundle next chunk in the next round. */ 620 break; 621 622 case SCTP_XMIT_RWND_FULL: 623 /* Send this packet. */ 624 error = sctp_packet_transmit(pkt); 625 626 /* Stop sending DATA as there is no more room 627 * at the receiver. 628 */ 629 done = 1; 630 break; 631 632 case SCTP_XMIT_NAGLE_DELAY: 633 /* Send this packet. */ 634 error = sctp_packet_transmit(pkt); 635 636 /* Stop sending DATA because of nagle delay. */ 637 done = 1; 638 break; 639 640 default: 641 /* The append was successful, so add this chunk to 642 * the transmitted list. 643 */ 644 list_del(&chunk->transmitted_list); 645 list_add_tail(&chunk->transmitted_list, 646 &transport->transmitted); 647 648 /* Mark the chunk as ineligible for fast retransmit 649 * after it is retransmitted. 650 */ 651 if (chunk->fast_retransmit > 0) 652 chunk->fast_retransmit = -1; 653 654 /* Force start T3-rtx timer when fast retransmitting 655 * the earliest outstanding TSN 656 */ 657 if (!timer && fast_rtx && 658 ntohl(chunk->subh.data_hdr->tsn) == 659 asoc->ctsn_ack_point + 1) 660 timer = 2; 661 662 q->empty = 0; 663 break; 664 } 665 666 /* Set the timer if there were no errors */ 667 if (!error && !timer) 668 timer = 1; 669 670 if (done) 671 break; 672 } 673 674 /* If we are here due to a retransmit timeout or a fast 675 * retransmit and if there are any chunks left in the retransmit 676 * queue that could not fit in the PMTU sized packet, they need 677 * to be marked as ineligible for a subsequent fast retransmit. 678 */ 679 if (rtx_timeout || fast_rtx) { 680 list_for_each_entry(chunk1, lqueue, transmitted_list) { 681 if (chunk1->fast_retransmit > 0) 682 chunk1->fast_retransmit = -1; 683 } 684 } 685 686 *start_timer = timer; 687 688 /* Clear fast retransmit hint */ 689 if (fast_rtx) 690 q->fast_rtx = 0; 691 692 return error; 693 } 694 695 /* Cork the outqueue so queued chunks are really queued. */ 696 int sctp_outq_uncork(struct sctp_outq *q) 697 { 698 int error = 0; 699 if (q->cork) 700 q->cork = 0; 701 error = sctp_outq_flush(q, 0); 702 return error; 703 } 704 705 706 /* 707 * Try to flush an outqueue. 708 * 709 * Description: Send everything in q which we legally can, subject to 710 * congestion limitations. 711 * * Note: This function can be called from multiple contexts so appropriate 712 * locking concerns must be made. Today we use the sock lock to protect 713 * this function. 714 */ 715 int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout) 716 { 717 struct sctp_packet *packet; 718 struct sctp_packet singleton; 719 struct sctp_association *asoc = q->asoc; 720 __u16 sport = asoc->base.bind_addr.port; 721 __u16 dport = asoc->peer.port; 722 __u32 vtag = asoc->peer.i.init_tag; 723 struct sctp_transport *transport = NULL; 724 struct sctp_transport *new_transport; 725 struct sctp_chunk *chunk, *tmp; 726 sctp_xmit_t status; 727 int error = 0; 728 int start_timer = 0; 729 int one_packet = 0; 730 731 /* These transports have chunks to send. */ 732 struct list_head transport_list; 733 struct list_head *ltransport; 734 735 INIT_LIST_HEAD(&transport_list); 736 packet = NULL; 737 738 /* 739 * 6.10 Bundling 740 * ... 741 * When bundling control chunks with DATA chunks, an 742 * endpoint MUST place control chunks first in the outbound 743 * SCTP packet. The transmitter MUST transmit DATA chunks 744 * within a SCTP packet in increasing order of TSN. 745 * ... 746 */ 747 748 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) { 749 list_del_init(&chunk->list); 750 751 /* Pick the right transport to use. */ 752 new_transport = chunk->transport; 753 754 if (!new_transport) { 755 /* 756 * If we have a prior transport pointer, see if 757 * the destination address of the chunk 758 * matches the destination address of the 759 * current transport. If not a match, then 760 * try to look up the transport with a given 761 * destination address. We do this because 762 * after processing ASCONFs, we may have new 763 * transports created. 764 */ 765 if (transport && 766 sctp_cmp_addr_exact(&chunk->dest, 767 &transport->ipaddr)) 768 new_transport = transport; 769 else 770 new_transport = sctp_assoc_lookup_paddr(asoc, 771 &chunk->dest); 772 773 /* if we still don't have a new transport, then 774 * use the current active path. 775 */ 776 if (!new_transport) 777 new_transport = asoc->peer.active_path; 778 } else if ((new_transport->state == SCTP_INACTIVE) || 779 (new_transport->state == SCTP_UNCONFIRMED)) { 780 /* If the chunk is Heartbeat or Heartbeat Ack, 781 * send it to chunk->transport, even if it's 782 * inactive. 783 * 784 * 3.3.6 Heartbeat Acknowledgement: 785 * ... 786 * A HEARTBEAT ACK is always sent to the source IP 787 * address of the IP datagram containing the 788 * HEARTBEAT chunk to which this ack is responding. 789 * ... 790 * 791 * ASCONF_ACKs also must be sent to the source. 792 */ 793 if (chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT && 794 chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT_ACK && 795 chunk->chunk_hdr->type != SCTP_CID_ASCONF_ACK) 796 new_transport = asoc->peer.active_path; 797 } 798 799 /* Are we switching transports? 800 * Take care of transport locks. 801 */ 802 if (new_transport != transport) { 803 transport = new_transport; 804 if (list_empty(&transport->send_ready)) { 805 list_add_tail(&transport->send_ready, 806 &transport_list); 807 } 808 packet = &transport->packet; 809 sctp_packet_config(packet, vtag, 810 asoc->peer.ecn_capable); 811 } 812 813 switch (chunk->chunk_hdr->type) { 814 /* 815 * 6.10 Bundling 816 * ... 817 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN 818 * COMPLETE with any other chunks. [Send them immediately.] 819 */ 820 case SCTP_CID_INIT: 821 case SCTP_CID_INIT_ACK: 822 case SCTP_CID_SHUTDOWN_COMPLETE: 823 sctp_packet_init(&singleton, transport, sport, dport); 824 sctp_packet_config(&singleton, vtag, 0); 825 sctp_packet_append_chunk(&singleton, chunk); 826 error = sctp_packet_transmit(&singleton); 827 if (error < 0) 828 return error; 829 break; 830 831 case SCTP_CID_ABORT: 832 if (sctp_test_T_bit(chunk)) { 833 packet->vtag = asoc->c.my_vtag; 834 } 835 /* The following chunks are "response" chunks, i.e. 836 * they are generated in response to something we 837 * received. If we are sending these, then we can 838 * send only 1 packet containing these chunks. 839 */ 840 case SCTP_CID_HEARTBEAT_ACK: 841 case SCTP_CID_SHUTDOWN_ACK: 842 case SCTP_CID_COOKIE_ACK: 843 case SCTP_CID_COOKIE_ECHO: 844 case SCTP_CID_ERROR: 845 case SCTP_CID_ECN_CWR: 846 case SCTP_CID_ASCONF_ACK: 847 one_packet = 1; 848 /* Fall throught */ 849 850 case SCTP_CID_SACK: 851 case SCTP_CID_HEARTBEAT: 852 case SCTP_CID_SHUTDOWN: 853 case SCTP_CID_ECN_ECNE: 854 case SCTP_CID_ASCONF: 855 case SCTP_CID_FWD_TSN: 856 status = sctp_packet_transmit_chunk(packet, chunk, 857 one_packet); 858 if (status != SCTP_XMIT_OK) { 859 /* put the chunk back */ 860 list_add(&chunk->list, &q->control_chunk_list); 861 } 862 break; 863 864 default: 865 /* We built a chunk with an illegal type! */ 866 BUG(); 867 } 868 } 869 870 /* Is it OK to send data chunks? */ 871 switch (asoc->state) { 872 case SCTP_STATE_COOKIE_ECHOED: 873 /* Only allow bundling when this packet has a COOKIE-ECHO 874 * chunk. 875 */ 876 if (!packet || !packet->has_cookie_echo) 877 break; 878 879 /* fallthru */ 880 case SCTP_STATE_ESTABLISHED: 881 case SCTP_STATE_SHUTDOWN_PENDING: 882 case SCTP_STATE_SHUTDOWN_RECEIVED: 883 /* 884 * RFC 2960 6.1 Transmission of DATA Chunks 885 * 886 * C) When the time comes for the sender to transmit, 887 * before sending new DATA chunks, the sender MUST 888 * first transmit any outstanding DATA chunks which 889 * are marked for retransmission (limited by the 890 * current cwnd). 891 */ 892 if (!list_empty(&q->retransmit)) { 893 if (transport == asoc->peer.retran_path) 894 goto retran; 895 896 /* Switch transports & prepare the packet. */ 897 898 transport = asoc->peer.retran_path; 899 900 if (list_empty(&transport->send_ready)) { 901 list_add_tail(&transport->send_ready, 902 &transport_list); 903 } 904 905 packet = &transport->packet; 906 sctp_packet_config(packet, vtag, 907 asoc->peer.ecn_capable); 908 retran: 909 error = sctp_outq_flush_rtx(q, packet, 910 rtx_timeout, &start_timer); 911 912 if (start_timer) 913 sctp_transport_reset_timers(transport, 914 start_timer-1); 915 916 /* This can happen on COOKIE-ECHO resend. Only 917 * one chunk can get bundled with a COOKIE-ECHO. 918 */ 919 if (packet->has_cookie_echo) 920 goto sctp_flush_out; 921 922 /* Don't send new data if there is still data 923 * waiting to retransmit. 924 */ 925 if (!list_empty(&q->retransmit)) 926 goto sctp_flush_out; 927 } 928 929 /* Finally, transmit new packets. */ 930 start_timer = 0; 931 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) { 932 /* RFC 2960 6.5 Every DATA chunk MUST carry a valid 933 * stream identifier. 934 */ 935 if (chunk->sinfo.sinfo_stream >= 936 asoc->c.sinit_num_ostreams) { 937 938 /* Mark as failed send. */ 939 sctp_chunk_fail(chunk, SCTP_ERROR_INV_STRM); 940 sctp_chunk_free(chunk); 941 continue; 942 } 943 944 /* Has this chunk expired? */ 945 if (sctp_chunk_abandoned(chunk)) { 946 sctp_chunk_fail(chunk, 0); 947 sctp_chunk_free(chunk); 948 continue; 949 } 950 951 /* If there is a specified transport, use it. 952 * Otherwise, we want to use the active path. 953 */ 954 new_transport = chunk->transport; 955 if (!new_transport || 956 ((new_transport->state == SCTP_INACTIVE) || 957 (new_transport->state == SCTP_UNCONFIRMED))) 958 new_transport = asoc->peer.active_path; 959 960 /* Change packets if necessary. */ 961 if (new_transport != transport) { 962 transport = new_transport; 963 964 /* Schedule to have this transport's 965 * packet flushed. 966 */ 967 if (list_empty(&transport->send_ready)) { 968 list_add_tail(&transport->send_ready, 969 &transport_list); 970 } 971 972 packet = &transport->packet; 973 sctp_packet_config(packet, vtag, 974 asoc->peer.ecn_capable); 975 } 976 977 SCTP_DEBUG_PRINTK("sctp_outq_flush(%p, %p[%s]), ", 978 q, chunk, 979 chunk && chunk->chunk_hdr ? 980 sctp_cname(SCTP_ST_CHUNK( 981 chunk->chunk_hdr->type)) 982 : "Illegal Chunk"); 983 984 SCTP_DEBUG_PRINTK("TX TSN 0x%x skb->head " 985 "%p skb->users %d.\n", 986 ntohl(chunk->subh.data_hdr->tsn), 987 chunk->skb ?chunk->skb->head : NULL, 988 chunk->skb ? 989 atomic_read(&chunk->skb->users) : -1); 990 991 /* Add the chunk to the packet. */ 992 status = sctp_packet_transmit_chunk(packet, chunk, 0); 993 994 switch (status) { 995 case SCTP_XMIT_PMTU_FULL: 996 case SCTP_XMIT_RWND_FULL: 997 case SCTP_XMIT_NAGLE_DELAY: 998 /* We could not append this chunk, so put 999 * the chunk back on the output queue. 1000 */ 1001 SCTP_DEBUG_PRINTK("sctp_outq_flush: could " 1002 "not transmit TSN: 0x%x, status: %d\n", 1003 ntohl(chunk->subh.data_hdr->tsn), 1004 status); 1005 sctp_outq_head_data(q, chunk); 1006 goto sctp_flush_out; 1007 break; 1008 1009 case SCTP_XMIT_OK: 1010 break; 1011 1012 default: 1013 BUG(); 1014 } 1015 1016 /* BUG: We assume that the sctp_packet_transmit() 1017 * call below will succeed all the time and add the 1018 * chunk to the transmitted list and restart the 1019 * timers. 1020 * It is possible that the call can fail under OOM 1021 * conditions. 1022 * 1023 * Is this really a problem? Won't this behave 1024 * like a lost TSN? 1025 */ 1026 list_add_tail(&chunk->transmitted_list, 1027 &transport->transmitted); 1028 1029 sctp_transport_reset_timers(transport, start_timer-1); 1030 1031 q->empty = 0; 1032 1033 /* Only let one DATA chunk get bundled with a 1034 * COOKIE-ECHO chunk. 1035 */ 1036 if (packet->has_cookie_echo) 1037 goto sctp_flush_out; 1038 } 1039 break; 1040 1041 default: 1042 /* Do nothing. */ 1043 break; 1044 } 1045 1046 sctp_flush_out: 1047 1048 /* Before returning, examine all the transports touched in 1049 * this call. Right now, we bluntly force clear all the 1050 * transports. Things might change after we implement Nagle. 1051 * But such an examination is still required. 1052 * 1053 * --xguo 1054 */ 1055 while ((ltransport = sctp_list_dequeue(&transport_list)) != NULL ) { 1056 struct sctp_transport *t = list_entry(ltransport, 1057 struct sctp_transport, 1058 send_ready); 1059 packet = &t->packet; 1060 if (!sctp_packet_empty(packet)) 1061 error = sctp_packet_transmit(packet); 1062 } 1063 1064 return error; 1065 } 1066 1067 /* Update unack_data based on the incoming SACK chunk */ 1068 static void sctp_sack_update_unack_data(struct sctp_association *assoc, 1069 struct sctp_sackhdr *sack) 1070 { 1071 sctp_sack_variable_t *frags; 1072 __u16 unack_data; 1073 int i; 1074 1075 unack_data = assoc->next_tsn - assoc->ctsn_ack_point - 1; 1076 1077 frags = sack->variable; 1078 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); i++) { 1079 unack_data -= ((ntohs(frags[i].gab.end) - 1080 ntohs(frags[i].gab.start) + 1)); 1081 } 1082 1083 assoc->unack_data = unack_data; 1084 } 1085 1086 /* Return the highest new tsn that is acknowledged by the given SACK chunk. */ 1087 static __u32 sctp_highest_new_tsn(struct sctp_sackhdr *sack, 1088 struct sctp_association *asoc) 1089 { 1090 struct sctp_transport *transport; 1091 struct sctp_chunk *chunk; 1092 __u32 highest_new_tsn, tsn; 1093 struct list_head *transport_list = &asoc->peer.transport_addr_list; 1094 1095 highest_new_tsn = ntohl(sack->cum_tsn_ack); 1096 1097 list_for_each_entry(transport, transport_list, transports) { 1098 list_for_each_entry(chunk, &transport->transmitted, 1099 transmitted_list) { 1100 tsn = ntohl(chunk->subh.data_hdr->tsn); 1101 1102 if (!chunk->tsn_gap_acked && 1103 TSN_lt(highest_new_tsn, tsn) && 1104 sctp_acked(sack, tsn)) 1105 highest_new_tsn = tsn; 1106 } 1107 } 1108 1109 return highest_new_tsn; 1110 } 1111 1112 /* This is where we REALLY process a SACK. 1113 * 1114 * Process the SACK against the outqueue. Mostly, this just frees 1115 * things off the transmitted queue. 1116 */ 1117 int sctp_outq_sack(struct sctp_outq *q, struct sctp_sackhdr *sack) 1118 { 1119 struct sctp_association *asoc = q->asoc; 1120 struct sctp_transport *transport; 1121 struct sctp_chunk *tchunk = NULL; 1122 struct list_head *lchunk, *transport_list, *temp; 1123 sctp_sack_variable_t *frags = sack->variable; 1124 __u32 sack_ctsn, ctsn, tsn; 1125 __u32 highest_tsn, highest_new_tsn; 1126 __u32 sack_a_rwnd; 1127 unsigned outstanding; 1128 struct sctp_transport *primary = asoc->peer.primary_path; 1129 int count_of_newacks = 0; 1130 1131 /* Grab the association's destination address list. */ 1132 transport_list = &asoc->peer.transport_addr_list; 1133 1134 sack_ctsn = ntohl(sack->cum_tsn_ack); 1135 1136 /* 1137 * SFR-CACC algorithm: 1138 * On receipt of a SACK the sender SHOULD execute the 1139 * following statements. 1140 * 1141 * 1) If the cumulative ack in the SACK passes next tsn_at_change 1142 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be 1143 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for 1144 * all destinations. 1145 */ 1146 if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) { 1147 primary->cacc.changeover_active = 0; 1148 list_for_each_entry(transport, transport_list, 1149 transports) { 1150 transport->cacc.cycling_changeover = 0; 1151 } 1152 } 1153 1154 /* 1155 * SFR-CACC algorithm: 1156 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE 1157 * is set the receiver of the SACK MUST take the following actions: 1158 * 1159 * A) Initialize the cacc_saw_newack to 0 for all destination 1160 * addresses. 1161 */ 1162 if (sack->num_gap_ack_blocks && 1163 primary->cacc.changeover_active) { 1164 list_for_each_entry(transport, transport_list, transports) { 1165 transport->cacc.cacc_saw_newack = 0; 1166 } 1167 } 1168 1169 /* Get the highest TSN in the sack. */ 1170 highest_tsn = sack_ctsn; 1171 if (sack->num_gap_ack_blocks) 1172 highest_tsn += 1173 ntohs(frags[ntohs(sack->num_gap_ack_blocks) - 1].gab.end); 1174 1175 if (TSN_lt(asoc->highest_sacked, highest_tsn)) { 1176 highest_new_tsn = highest_tsn; 1177 asoc->highest_sacked = highest_tsn; 1178 } else { 1179 highest_new_tsn = sctp_highest_new_tsn(sack, asoc); 1180 } 1181 1182 /* Run through the retransmit queue. Credit bytes received 1183 * and free those chunks that we can. 1184 */ 1185 sctp_check_transmitted(q, &q->retransmit, NULL, sack, highest_new_tsn); 1186 sctp_mark_missing(q, &q->retransmit, NULL, highest_new_tsn, 0); 1187 1188 /* Run through the transmitted queue. 1189 * Credit bytes received and free those chunks which we can. 1190 * 1191 * This is a MASSIVE candidate for optimization. 1192 */ 1193 list_for_each_entry(transport, transport_list, transports) { 1194 sctp_check_transmitted(q, &transport->transmitted, 1195 transport, sack, highest_new_tsn); 1196 /* 1197 * SFR-CACC algorithm: 1198 * C) Let count_of_newacks be the number of 1199 * destinations for which cacc_saw_newack is set. 1200 */ 1201 if (transport->cacc.cacc_saw_newack) 1202 count_of_newacks ++; 1203 } 1204 1205 list_for_each_entry(transport, transport_list, transports) { 1206 sctp_mark_missing(q, &transport->transmitted, transport, 1207 highest_new_tsn, count_of_newacks); 1208 } 1209 1210 /* Move the Cumulative TSN Ack Point if appropriate. */ 1211 if (TSN_lt(asoc->ctsn_ack_point, sack_ctsn)) 1212 asoc->ctsn_ack_point = sack_ctsn; 1213 1214 /* Update unack_data field in the assoc. */ 1215 sctp_sack_update_unack_data(asoc, sack); 1216 1217 ctsn = asoc->ctsn_ack_point; 1218 1219 /* Throw away stuff rotting on the sack queue. */ 1220 list_for_each_safe(lchunk, temp, &q->sacked) { 1221 tchunk = list_entry(lchunk, struct sctp_chunk, 1222 transmitted_list); 1223 tsn = ntohl(tchunk->subh.data_hdr->tsn); 1224 if (TSN_lte(tsn, ctsn)) { 1225 list_del_init(&tchunk->transmitted_list); 1226 sctp_chunk_free(tchunk); 1227 } 1228 } 1229 1230 /* ii) Set rwnd equal to the newly received a_rwnd minus the 1231 * number of bytes still outstanding after processing the 1232 * Cumulative TSN Ack and the Gap Ack Blocks. 1233 */ 1234 1235 sack_a_rwnd = ntohl(sack->a_rwnd); 1236 outstanding = q->outstanding_bytes; 1237 1238 if (outstanding < sack_a_rwnd) 1239 sack_a_rwnd -= outstanding; 1240 else 1241 sack_a_rwnd = 0; 1242 1243 asoc->peer.rwnd = sack_a_rwnd; 1244 1245 sctp_generate_fwdtsn(q, sack_ctsn); 1246 1247 SCTP_DEBUG_PRINTK("%s: sack Cumulative TSN Ack is 0x%x.\n", 1248 __func__, sack_ctsn); 1249 SCTP_DEBUG_PRINTK("%s: Cumulative TSN Ack of association, " 1250 "%p is 0x%x. Adv peer ack point: 0x%x\n", 1251 __func__, asoc, ctsn, asoc->adv_peer_ack_point); 1252 1253 /* See if all chunks are acked. 1254 * Make sure the empty queue handler will get run later. 1255 */ 1256 q->empty = (list_empty(&q->out_chunk_list) && 1257 list_empty(&q->retransmit)); 1258 if (!q->empty) 1259 goto finish; 1260 1261 list_for_each_entry(transport, transport_list, transports) { 1262 q->empty = q->empty && list_empty(&transport->transmitted); 1263 if (!q->empty) 1264 goto finish; 1265 } 1266 1267 SCTP_DEBUG_PRINTK("sack queue is empty.\n"); 1268 finish: 1269 return q->empty; 1270 } 1271 1272 /* Is the outqueue empty? */ 1273 int sctp_outq_is_empty(const struct sctp_outq *q) 1274 { 1275 return q->empty; 1276 } 1277 1278 /******************************************************************** 1279 * 2nd Level Abstractions 1280 ********************************************************************/ 1281 1282 /* Go through a transport's transmitted list or the association's retransmit 1283 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked. 1284 * The retransmit list will not have an associated transport. 1285 * 1286 * I added coherent debug information output. --xguo 1287 * 1288 * Instead of printing 'sacked' or 'kept' for each TSN on the 1289 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5. 1290 * KEPT TSN6-TSN7, etc. 1291 */ 1292 static void sctp_check_transmitted(struct sctp_outq *q, 1293 struct list_head *transmitted_queue, 1294 struct sctp_transport *transport, 1295 struct sctp_sackhdr *sack, 1296 __u32 highest_new_tsn_in_sack) 1297 { 1298 struct list_head *lchunk; 1299 struct sctp_chunk *tchunk; 1300 struct list_head tlist; 1301 __u32 tsn; 1302 __u32 sack_ctsn; 1303 __u32 rtt; 1304 __u8 restart_timer = 0; 1305 int bytes_acked = 0; 1306 1307 /* These state variables are for coherent debug output. --xguo */ 1308 1309 #if SCTP_DEBUG 1310 __u32 dbg_ack_tsn = 0; /* An ACKed TSN range starts here... */ 1311 __u32 dbg_last_ack_tsn = 0; /* ...and finishes here. */ 1312 __u32 dbg_kept_tsn = 0; /* An un-ACKed range starts here... */ 1313 __u32 dbg_last_kept_tsn = 0; /* ...and finishes here. */ 1314 1315 /* 0 : The last TSN was ACKed. 1316 * 1 : The last TSN was NOT ACKed (i.e. KEPT). 1317 * -1: We need to initialize. 1318 */ 1319 int dbg_prt_state = -1; 1320 #endif /* SCTP_DEBUG */ 1321 1322 sack_ctsn = ntohl(sack->cum_tsn_ack); 1323 1324 INIT_LIST_HEAD(&tlist); 1325 1326 /* The while loop will skip empty transmitted queues. */ 1327 while (NULL != (lchunk = sctp_list_dequeue(transmitted_queue))) { 1328 tchunk = list_entry(lchunk, struct sctp_chunk, 1329 transmitted_list); 1330 1331 if (sctp_chunk_abandoned(tchunk)) { 1332 /* Move the chunk to abandoned list. */ 1333 sctp_insert_list(&q->abandoned, lchunk); 1334 1335 /* If this chunk has not been acked, stop 1336 * considering it as 'outstanding'. 1337 */ 1338 if (!tchunk->tsn_gap_acked) { 1339 tchunk->transport->flight_size -= 1340 sctp_data_size(tchunk); 1341 q->outstanding_bytes -= sctp_data_size(tchunk); 1342 } 1343 continue; 1344 } 1345 1346 tsn = ntohl(tchunk->subh.data_hdr->tsn); 1347 if (sctp_acked(sack, tsn)) { 1348 /* If this queue is the retransmit queue, the 1349 * retransmit timer has already reclaimed 1350 * the outstanding bytes for this chunk, so only 1351 * count bytes associated with a transport. 1352 */ 1353 if (transport) { 1354 /* If this chunk is being used for RTT 1355 * measurement, calculate the RTT and update 1356 * the RTO using this value. 1357 * 1358 * 6.3.1 C5) Karn's algorithm: RTT measurements 1359 * MUST NOT be made using packets that were 1360 * retransmitted (and thus for which it is 1361 * ambiguous whether the reply was for the 1362 * first instance of the packet or a later 1363 * instance). 1364 */ 1365 if (!tchunk->tsn_gap_acked && 1366 !tchunk->resent && 1367 tchunk->rtt_in_progress) { 1368 tchunk->rtt_in_progress = 0; 1369 rtt = jiffies - tchunk->sent_at; 1370 sctp_transport_update_rto(transport, 1371 rtt); 1372 } 1373 } 1374 if (TSN_lte(tsn, sack_ctsn)) { 1375 /* RFC 2960 6.3.2 Retransmission Timer Rules 1376 * 1377 * R3) Whenever a SACK is received 1378 * that acknowledges the DATA chunk 1379 * with the earliest outstanding TSN 1380 * for that address, restart T3-rtx 1381 * timer for that address with its 1382 * current RTO. 1383 */ 1384 restart_timer = 1; 1385 1386 if (!tchunk->tsn_gap_acked) { 1387 tchunk->tsn_gap_acked = 1; 1388 bytes_acked += sctp_data_size(tchunk); 1389 /* 1390 * SFR-CACC algorithm: 1391 * 2) If the SACK contains gap acks 1392 * and the flag CHANGEOVER_ACTIVE is 1393 * set the receiver of the SACK MUST 1394 * take the following action: 1395 * 1396 * B) For each TSN t being acked that 1397 * has not been acked in any SACK so 1398 * far, set cacc_saw_newack to 1 for 1399 * the destination that the TSN was 1400 * sent to. 1401 */ 1402 if (transport && 1403 sack->num_gap_ack_blocks && 1404 q->asoc->peer.primary_path->cacc. 1405 changeover_active) 1406 transport->cacc.cacc_saw_newack 1407 = 1; 1408 } 1409 1410 list_add_tail(&tchunk->transmitted_list, 1411 &q->sacked); 1412 } else { 1413 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2 1414 * M2) Each time a SACK arrives reporting 1415 * 'Stray DATA chunk(s)' record the highest TSN 1416 * reported as newly acknowledged, call this 1417 * value 'HighestTSNinSack'. A newly 1418 * acknowledged DATA chunk is one not 1419 * previously acknowledged in a SACK. 1420 * 1421 * When the SCTP sender of data receives a SACK 1422 * chunk that acknowledges, for the first time, 1423 * the receipt of a DATA chunk, all the still 1424 * unacknowledged DATA chunks whose TSN is 1425 * older than that newly acknowledged DATA 1426 * chunk, are qualified as 'Stray DATA chunks'. 1427 */ 1428 if (!tchunk->tsn_gap_acked) { 1429 tchunk->tsn_gap_acked = 1; 1430 bytes_acked += sctp_data_size(tchunk); 1431 } 1432 list_add_tail(lchunk, &tlist); 1433 } 1434 1435 #if SCTP_DEBUG 1436 switch (dbg_prt_state) { 1437 case 0: /* last TSN was ACKed */ 1438 if (dbg_last_ack_tsn + 1 == tsn) { 1439 /* This TSN belongs to the 1440 * current ACK range. 1441 */ 1442 break; 1443 } 1444 1445 if (dbg_last_ack_tsn != dbg_ack_tsn) { 1446 /* Display the end of the 1447 * current range. 1448 */ 1449 SCTP_DEBUG_PRINTK("-%08x", 1450 dbg_last_ack_tsn); 1451 } 1452 1453 /* Start a new range. */ 1454 SCTP_DEBUG_PRINTK(",%08x", tsn); 1455 dbg_ack_tsn = tsn; 1456 break; 1457 1458 case 1: /* The last TSN was NOT ACKed. */ 1459 if (dbg_last_kept_tsn != dbg_kept_tsn) { 1460 /* Display the end of current range. */ 1461 SCTP_DEBUG_PRINTK("-%08x", 1462 dbg_last_kept_tsn); 1463 } 1464 1465 SCTP_DEBUG_PRINTK("\n"); 1466 1467 /* FALL THROUGH... */ 1468 default: 1469 /* This is the first-ever TSN we examined. */ 1470 /* Start a new range of ACK-ed TSNs. */ 1471 SCTP_DEBUG_PRINTK("ACKed: %08x", tsn); 1472 dbg_prt_state = 0; 1473 dbg_ack_tsn = tsn; 1474 } 1475 1476 dbg_last_ack_tsn = tsn; 1477 #endif /* SCTP_DEBUG */ 1478 1479 } else { 1480 if (tchunk->tsn_gap_acked) { 1481 SCTP_DEBUG_PRINTK("%s: Receiver reneged on " 1482 "data TSN: 0x%x\n", 1483 __func__, 1484 tsn); 1485 tchunk->tsn_gap_acked = 0; 1486 1487 bytes_acked -= sctp_data_size(tchunk); 1488 1489 /* RFC 2960 6.3.2 Retransmission Timer Rules 1490 * 1491 * R4) Whenever a SACK is received missing a 1492 * TSN that was previously acknowledged via a 1493 * Gap Ack Block, start T3-rtx for the 1494 * destination address to which the DATA 1495 * chunk was originally 1496 * transmitted if it is not already running. 1497 */ 1498 restart_timer = 1; 1499 } 1500 1501 list_add_tail(lchunk, &tlist); 1502 1503 #if SCTP_DEBUG 1504 /* See the above comments on ACK-ed TSNs. */ 1505 switch (dbg_prt_state) { 1506 case 1: 1507 if (dbg_last_kept_tsn + 1 == tsn) 1508 break; 1509 1510 if (dbg_last_kept_tsn != dbg_kept_tsn) 1511 SCTP_DEBUG_PRINTK("-%08x", 1512 dbg_last_kept_tsn); 1513 1514 SCTP_DEBUG_PRINTK(",%08x", tsn); 1515 dbg_kept_tsn = tsn; 1516 break; 1517 1518 case 0: 1519 if (dbg_last_ack_tsn != dbg_ack_tsn) 1520 SCTP_DEBUG_PRINTK("-%08x", 1521 dbg_last_ack_tsn); 1522 SCTP_DEBUG_PRINTK("\n"); 1523 1524 /* FALL THROUGH... */ 1525 default: 1526 SCTP_DEBUG_PRINTK("KEPT: %08x",tsn); 1527 dbg_prt_state = 1; 1528 dbg_kept_tsn = tsn; 1529 } 1530 1531 dbg_last_kept_tsn = tsn; 1532 #endif /* SCTP_DEBUG */ 1533 } 1534 } 1535 1536 #if SCTP_DEBUG 1537 /* Finish off the last range, displaying its ending TSN. */ 1538 switch (dbg_prt_state) { 1539 case 0: 1540 if (dbg_last_ack_tsn != dbg_ack_tsn) { 1541 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_ack_tsn); 1542 } else { 1543 SCTP_DEBUG_PRINTK("\n"); 1544 } 1545 break; 1546 1547 case 1: 1548 if (dbg_last_kept_tsn != dbg_kept_tsn) { 1549 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_kept_tsn); 1550 } else { 1551 SCTP_DEBUG_PRINTK("\n"); 1552 } 1553 } 1554 #endif /* SCTP_DEBUG */ 1555 if (transport) { 1556 if (bytes_acked) { 1557 /* 8.2. When an outstanding TSN is acknowledged, 1558 * the endpoint shall clear the error counter of 1559 * the destination transport address to which the 1560 * DATA chunk was last sent. 1561 * The association's overall error counter is 1562 * also cleared. 1563 */ 1564 transport->error_count = 0; 1565 transport->asoc->overall_error_count = 0; 1566 1567 /* Mark the destination transport address as 1568 * active if it is not so marked. 1569 */ 1570 if ((transport->state == SCTP_INACTIVE) || 1571 (transport->state == SCTP_UNCONFIRMED)) { 1572 sctp_assoc_control_transport( 1573 transport->asoc, 1574 transport, 1575 SCTP_TRANSPORT_UP, 1576 SCTP_RECEIVED_SACK); 1577 } 1578 1579 sctp_transport_raise_cwnd(transport, sack_ctsn, 1580 bytes_acked); 1581 1582 transport->flight_size -= bytes_acked; 1583 if (transport->flight_size == 0) 1584 transport->partial_bytes_acked = 0; 1585 q->outstanding_bytes -= bytes_acked; 1586 } else { 1587 /* RFC 2960 6.1, sctpimpguide-06 2.15.2 1588 * When a sender is doing zero window probing, it 1589 * should not timeout the association if it continues 1590 * to receive new packets from the receiver. The 1591 * reason is that the receiver MAY keep its window 1592 * closed for an indefinite time. 1593 * A sender is doing zero window probing when the 1594 * receiver's advertised window is zero, and there is 1595 * only one data chunk in flight to the receiver. 1596 */ 1597 if (!q->asoc->peer.rwnd && 1598 !list_empty(&tlist) && 1599 (sack_ctsn+2 == q->asoc->next_tsn)) { 1600 SCTP_DEBUG_PRINTK("%s: SACK received for zero " 1601 "window probe: %u\n", 1602 __func__, sack_ctsn); 1603 q->asoc->overall_error_count = 0; 1604 transport->error_count = 0; 1605 } 1606 } 1607 1608 /* RFC 2960 6.3.2 Retransmission Timer Rules 1609 * 1610 * R2) Whenever all outstanding data sent to an address have 1611 * been acknowledged, turn off the T3-rtx timer of that 1612 * address. 1613 */ 1614 if (!transport->flight_size) { 1615 if (timer_pending(&transport->T3_rtx_timer) && 1616 del_timer(&transport->T3_rtx_timer)) { 1617 sctp_transport_put(transport); 1618 } 1619 } else if (restart_timer) { 1620 if (!mod_timer(&transport->T3_rtx_timer, 1621 jiffies + transport->rto)) 1622 sctp_transport_hold(transport); 1623 } 1624 } 1625 1626 list_splice(&tlist, transmitted_queue); 1627 } 1628 1629 /* Mark chunks as missing and consequently may get retransmitted. */ 1630 static void sctp_mark_missing(struct sctp_outq *q, 1631 struct list_head *transmitted_queue, 1632 struct sctp_transport *transport, 1633 __u32 highest_new_tsn_in_sack, 1634 int count_of_newacks) 1635 { 1636 struct sctp_chunk *chunk; 1637 __u32 tsn; 1638 char do_fast_retransmit = 0; 1639 struct sctp_transport *primary = q->asoc->peer.primary_path; 1640 1641 list_for_each_entry(chunk, transmitted_queue, transmitted_list) { 1642 1643 tsn = ntohl(chunk->subh.data_hdr->tsn); 1644 1645 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all 1646 * 'Unacknowledged TSN's', if the TSN number of an 1647 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack' 1648 * value, increment the 'TSN.Missing.Report' count on that 1649 * chunk if it has NOT been fast retransmitted or marked for 1650 * fast retransmit already. 1651 */ 1652 if (!chunk->fast_retransmit && 1653 !chunk->tsn_gap_acked && 1654 TSN_lt(tsn, highest_new_tsn_in_sack)) { 1655 1656 /* SFR-CACC may require us to skip marking 1657 * this chunk as missing. 1658 */ 1659 if (!transport || !sctp_cacc_skip(primary, transport, 1660 count_of_newacks, tsn)) { 1661 chunk->tsn_missing_report++; 1662 1663 SCTP_DEBUG_PRINTK( 1664 "%s: TSN 0x%x missing counter: %d\n", 1665 __func__, tsn, 1666 chunk->tsn_missing_report); 1667 } 1668 } 1669 /* 1670 * M4) If any DATA chunk is found to have a 1671 * 'TSN.Missing.Report' 1672 * value larger than or equal to 3, mark that chunk for 1673 * retransmission and start the fast retransmit procedure. 1674 */ 1675 1676 if (chunk->tsn_missing_report >= 3) { 1677 chunk->fast_retransmit = 1; 1678 do_fast_retransmit = 1; 1679 } 1680 } 1681 1682 if (transport) { 1683 if (do_fast_retransmit) 1684 sctp_retransmit(q, transport, SCTP_RTXR_FAST_RTX); 1685 1686 SCTP_DEBUG_PRINTK("%s: transport: %p, cwnd: %d, " 1687 "ssthresh: %d, flight_size: %d, pba: %d\n", 1688 __func__, transport, transport->cwnd, 1689 transport->ssthresh, transport->flight_size, 1690 transport->partial_bytes_acked); 1691 } 1692 } 1693 1694 /* Is the given TSN acked by this packet? */ 1695 static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn) 1696 { 1697 int i; 1698 sctp_sack_variable_t *frags; 1699 __u16 gap; 1700 __u32 ctsn = ntohl(sack->cum_tsn_ack); 1701 1702 if (TSN_lte(tsn, ctsn)) 1703 goto pass; 1704 1705 /* 3.3.4 Selective Acknowledgement (SACK) (3): 1706 * 1707 * Gap Ack Blocks: 1708 * These fields contain the Gap Ack Blocks. They are repeated 1709 * for each Gap Ack Block up to the number of Gap Ack Blocks 1710 * defined in the Number of Gap Ack Blocks field. All DATA 1711 * chunks with TSNs greater than or equal to (Cumulative TSN 1712 * Ack + Gap Ack Block Start) and less than or equal to 1713 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack 1714 * Block are assumed to have been received correctly. 1715 */ 1716 1717 frags = sack->variable; 1718 gap = tsn - ctsn; 1719 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); ++i) { 1720 if (TSN_lte(ntohs(frags[i].gab.start), gap) && 1721 TSN_lte(gap, ntohs(frags[i].gab.end))) 1722 goto pass; 1723 } 1724 1725 return 0; 1726 pass: 1727 return 1; 1728 } 1729 1730 static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip *skiplist, 1731 int nskips, __be16 stream) 1732 { 1733 int i; 1734 1735 for (i = 0; i < nskips; i++) { 1736 if (skiplist[i].stream == stream) 1737 return i; 1738 } 1739 return i; 1740 } 1741 1742 /* Create and add a fwdtsn chunk to the outq's control queue if needed. */ 1743 static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 ctsn) 1744 { 1745 struct sctp_association *asoc = q->asoc; 1746 struct sctp_chunk *ftsn_chunk = NULL; 1747 struct sctp_fwdtsn_skip ftsn_skip_arr[10]; 1748 int nskips = 0; 1749 int skip_pos = 0; 1750 __u32 tsn; 1751 struct sctp_chunk *chunk; 1752 struct list_head *lchunk, *temp; 1753 1754 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the 1755 * received SACK. 1756 * 1757 * If (Advanced.Peer.Ack.Point < SackCumAck), then update 1758 * Advanced.Peer.Ack.Point to be equal to SackCumAck. 1759 */ 1760 if (TSN_lt(asoc->adv_peer_ack_point, ctsn)) 1761 asoc->adv_peer_ack_point = ctsn; 1762 1763 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point" 1764 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as 1765 * the chunk next in the out-queue space is marked as "abandoned" as 1766 * shown in the following example: 1767 * 1768 * Assuming that a SACK arrived with the Cumulative TSN ACK 102 1769 * and the Advanced.Peer.Ack.Point is updated to this value: 1770 * 1771 * out-queue at the end of ==> out-queue after Adv.Ack.Point 1772 * normal SACK processing local advancement 1773 * ... ... 1774 * Adv.Ack.Pt-> 102 acked 102 acked 1775 * 103 abandoned 103 abandoned 1776 * 104 abandoned Adv.Ack.P-> 104 abandoned 1777 * 105 105 1778 * 106 acked 106 acked 1779 * ... ... 1780 * 1781 * In this example, the data sender successfully advanced the 1782 * "Advanced.Peer.Ack.Point" from 102 to 104 locally. 1783 */ 1784 list_for_each_safe(lchunk, temp, &q->abandoned) { 1785 chunk = list_entry(lchunk, struct sctp_chunk, 1786 transmitted_list); 1787 tsn = ntohl(chunk->subh.data_hdr->tsn); 1788 1789 /* Remove any chunks in the abandoned queue that are acked by 1790 * the ctsn. 1791 */ 1792 if (TSN_lte(tsn, ctsn)) { 1793 list_del_init(lchunk); 1794 sctp_chunk_free(chunk); 1795 } else { 1796 if (TSN_lte(tsn, asoc->adv_peer_ack_point+1)) { 1797 asoc->adv_peer_ack_point = tsn; 1798 if (chunk->chunk_hdr->flags & 1799 SCTP_DATA_UNORDERED) 1800 continue; 1801 skip_pos = sctp_get_skip_pos(&ftsn_skip_arr[0], 1802 nskips, 1803 chunk->subh.data_hdr->stream); 1804 ftsn_skip_arr[skip_pos].stream = 1805 chunk->subh.data_hdr->stream; 1806 ftsn_skip_arr[skip_pos].ssn = 1807 chunk->subh.data_hdr->ssn; 1808 if (skip_pos == nskips) 1809 nskips++; 1810 if (nskips == 10) 1811 break; 1812 } else 1813 break; 1814 } 1815 } 1816 1817 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point" 1818 * is greater than the Cumulative TSN ACK carried in the received 1819 * SACK, the data sender MUST send the data receiver a FORWARD TSN 1820 * chunk containing the latest value of the 1821 * "Advanced.Peer.Ack.Point". 1822 * 1823 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD 1824 * list each stream and sequence number in the forwarded TSN. This 1825 * information will enable the receiver to easily find any 1826 * stranded TSN's waiting on stream reorder queues. Each stream 1827 * SHOULD only be reported once; this means that if multiple 1828 * abandoned messages occur in the same stream then only the 1829 * highest abandoned stream sequence number is reported. If the 1830 * total size of the FORWARD TSN does NOT fit in a single MTU then 1831 * the sender of the FORWARD TSN SHOULD lower the 1832 * Advanced.Peer.Ack.Point to the last TSN that will fit in a 1833 * single MTU. 1834 */ 1835 if (asoc->adv_peer_ack_point > ctsn) 1836 ftsn_chunk = sctp_make_fwdtsn(asoc, asoc->adv_peer_ack_point, 1837 nskips, &ftsn_skip_arr[0]); 1838 1839 if (ftsn_chunk) { 1840 list_add_tail(&ftsn_chunk->list, &q->control_chunk_list); 1841 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 1842 } 1843 } 1844