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 * Try to flush an outqueue. 707 * 708 * Description: Send everything in q which we legally can, subject to 709 * congestion limitations. 710 * * Note: This function can be called from multiple contexts so appropriate 711 * locking concerns must be made. Today we use the sock lock to protect 712 * this function. 713 */ 714 int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout) 715 { 716 struct sctp_packet *packet; 717 struct sctp_packet singleton; 718 struct sctp_association *asoc = q->asoc; 719 __u16 sport = asoc->base.bind_addr.port; 720 __u16 dport = asoc->peer.port; 721 __u32 vtag = asoc->peer.i.init_tag; 722 struct sctp_transport *transport = NULL; 723 struct sctp_transport *new_transport; 724 struct sctp_chunk *chunk, *tmp; 725 sctp_xmit_t status; 726 int error = 0; 727 int start_timer = 0; 728 729 /* These transports have chunks to send. */ 730 struct list_head transport_list; 731 struct list_head *ltransport; 732 733 INIT_LIST_HEAD(&transport_list); 734 packet = NULL; 735 736 /* 737 * 6.10 Bundling 738 * ... 739 * When bundling control chunks with DATA chunks, an 740 * endpoint MUST place control chunks first in the outbound 741 * SCTP packet. The transmitter MUST transmit DATA chunks 742 * within a SCTP packet in increasing order of TSN. 743 * ... 744 */ 745 746 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) { 747 list_del_init(&chunk->list); 748 749 /* Pick the right transport to use. */ 750 new_transport = chunk->transport; 751 752 if (!new_transport) { 753 /* 754 * If we have a prior transport pointer, see if 755 * the destination address of the chunk 756 * matches the destination address of the 757 * current transport. If not a match, then 758 * try to look up the transport with a given 759 * destination address. We do this because 760 * after processing ASCONFs, we may have new 761 * transports created. 762 */ 763 if (transport && 764 sctp_cmp_addr_exact(&chunk->dest, 765 &transport->ipaddr)) 766 new_transport = transport; 767 else 768 new_transport = sctp_assoc_lookup_paddr(asoc, 769 &chunk->dest); 770 771 /* if we still don't have a new transport, then 772 * use the current active path. 773 */ 774 if (!new_transport) 775 new_transport = asoc->peer.active_path; 776 } else if ((new_transport->state == SCTP_INACTIVE) || 777 (new_transport->state == SCTP_UNCONFIRMED)) { 778 /* If the chunk is Heartbeat or Heartbeat Ack, 779 * send it to chunk->transport, even if it's 780 * inactive. 781 * 782 * 3.3.6 Heartbeat Acknowledgement: 783 * ... 784 * A HEARTBEAT ACK is always sent to the source IP 785 * address of the IP datagram containing the 786 * HEARTBEAT chunk to which this ack is responding. 787 * ... 788 * 789 * ASCONF_ACKs also must be sent to the source. 790 */ 791 if (chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT && 792 chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT_ACK && 793 chunk->chunk_hdr->type != SCTP_CID_ASCONF_ACK) 794 new_transport = asoc->peer.active_path; 795 } 796 797 /* Are we switching transports? 798 * Take care of transport locks. 799 */ 800 if (new_transport != transport) { 801 transport = new_transport; 802 if (list_empty(&transport->send_ready)) { 803 list_add_tail(&transport->send_ready, 804 &transport_list); 805 } 806 packet = &transport->packet; 807 sctp_packet_config(packet, vtag, 808 asoc->peer.ecn_capable); 809 } 810 811 switch (chunk->chunk_hdr->type) { 812 /* 813 * 6.10 Bundling 814 * ... 815 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN 816 * COMPLETE with any other chunks. [Send them immediately.] 817 */ 818 case SCTP_CID_INIT: 819 case SCTP_CID_INIT_ACK: 820 case SCTP_CID_SHUTDOWN_COMPLETE: 821 sctp_packet_init(&singleton, transport, sport, dport); 822 sctp_packet_config(&singleton, vtag, 0); 823 sctp_packet_append_chunk(&singleton, chunk); 824 error = sctp_packet_transmit(&singleton); 825 if (error < 0) 826 return error; 827 break; 828 829 case SCTP_CID_ABORT: 830 if (sctp_test_T_bit(chunk)) { 831 packet->vtag = asoc->c.my_vtag; 832 } 833 case SCTP_CID_SACK: 834 case SCTP_CID_HEARTBEAT: 835 case SCTP_CID_HEARTBEAT_ACK: 836 case SCTP_CID_SHUTDOWN: 837 case SCTP_CID_SHUTDOWN_ACK: 838 case SCTP_CID_ERROR: 839 case SCTP_CID_COOKIE_ECHO: 840 case SCTP_CID_COOKIE_ACK: 841 case SCTP_CID_ECN_ECNE: 842 case SCTP_CID_ECN_CWR: 843 case SCTP_CID_ASCONF: 844 case SCTP_CID_ASCONF_ACK: 845 case SCTP_CID_FWD_TSN: 846 sctp_packet_transmit_chunk(packet, chunk); 847 break; 848 849 default: 850 /* We built a chunk with an illegal type! */ 851 BUG(); 852 } 853 } 854 855 /* Is it OK to send data chunks? */ 856 switch (asoc->state) { 857 case SCTP_STATE_COOKIE_ECHOED: 858 /* Only allow bundling when this packet has a COOKIE-ECHO 859 * chunk. 860 */ 861 if (!packet || !packet->has_cookie_echo) 862 break; 863 864 /* fallthru */ 865 case SCTP_STATE_ESTABLISHED: 866 case SCTP_STATE_SHUTDOWN_PENDING: 867 case SCTP_STATE_SHUTDOWN_RECEIVED: 868 /* 869 * RFC 2960 6.1 Transmission of DATA Chunks 870 * 871 * C) When the time comes for the sender to transmit, 872 * before sending new DATA chunks, the sender MUST 873 * first transmit any outstanding DATA chunks which 874 * are marked for retransmission (limited by the 875 * current cwnd). 876 */ 877 if (!list_empty(&q->retransmit)) { 878 if (transport == asoc->peer.retran_path) 879 goto retran; 880 881 /* Switch transports & prepare the packet. */ 882 883 transport = asoc->peer.retran_path; 884 885 if (list_empty(&transport->send_ready)) { 886 list_add_tail(&transport->send_ready, 887 &transport_list); 888 } 889 890 packet = &transport->packet; 891 sctp_packet_config(packet, vtag, 892 asoc->peer.ecn_capable); 893 retran: 894 error = sctp_outq_flush_rtx(q, packet, 895 rtx_timeout, &start_timer); 896 897 if (start_timer) 898 sctp_transport_reset_timers(transport, 899 start_timer-1); 900 901 /* This can happen on COOKIE-ECHO resend. Only 902 * one chunk can get bundled with a COOKIE-ECHO. 903 */ 904 if (packet->has_cookie_echo) 905 goto sctp_flush_out; 906 907 /* Don't send new data if there is still data 908 * waiting to retransmit. 909 */ 910 if (!list_empty(&q->retransmit)) 911 goto sctp_flush_out; 912 } 913 914 /* Finally, transmit new packets. */ 915 start_timer = 0; 916 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) { 917 /* RFC 2960 6.5 Every DATA chunk MUST carry a valid 918 * stream identifier. 919 */ 920 if (chunk->sinfo.sinfo_stream >= 921 asoc->c.sinit_num_ostreams) { 922 923 /* Mark as failed send. */ 924 sctp_chunk_fail(chunk, SCTP_ERROR_INV_STRM); 925 sctp_chunk_free(chunk); 926 continue; 927 } 928 929 /* Has this chunk expired? */ 930 if (sctp_chunk_abandoned(chunk)) { 931 sctp_chunk_fail(chunk, 0); 932 sctp_chunk_free(chunk); 933 continue; 934 } 935 936 /* If there is a specified transport, use it. 937 * Otherwise, we want to use the active path. 938 */ 939 new_transport = chunk->transport; 940 if (!new_transport || 941 ((new_transport->state == SCTP_INACTIVE) || 942 (new_transport->state == SCTP_UNCONFIRMED))) 943 new_transport = asoc->peer.active_path; 944 945 /* Change packets if necessary. */ 946 if (new_transport != transport) { 947 transport = new_transport; 948 949 /* Schedule to have this transport's 950 * packet flushed. 951 */ 952 if (list_empty(&transport->send_ready)) { 953 list_add_tail(&transport->send_ready, 954 &transport_list); 955 } 956 957 packet = &transport->packet; 958 sctp_packet_config(packet, vtag, 959 asoc->peer.ecn_capable); 960 } 961 962 SCTP_DEBUG_PRINTK("sctp_outq_flush(%p, %p[%s]), ", 963 q, chunk, 964 chunk && chunk->chunk_hdr ? 965 sctp_cname(SCTP_ST_CHUNK( 966 chunk->chunk_hdr->type)) 967 : "Illegal Chunk"); 968 969 SCTP_DEBUG_PRINTK("TX TSN 0x%x skb->head " 970 "%p skb->users %d.\n", 971 ntohl(chunk->subh.data_hdr->tsn), 972 chunk->skb ?chunk->skb->head : NULL, 973 chunk->skb ? 974 atomic_read(&chunk->skb->users) : -1); 975 976 /* Add the chunk to the packet. */ 977 status = sctp_packet_transmit_chunk(packet, chunk); 978 979 switch (status) { 980 case SCTP_XMIT_PMTU_FULL: 981 case SCTP_XMIT_RWND_FULL: 982 case SCTP_XMIT_NAGLE_DELAY: 983 /* We could not append this chunk, so put 984 * the chunk back on the output queue. 985 */ 986 SCTP_DEBUG_PRINTK("sctp_outq_flush: could " 987 "not transmit TSN: 0x%x, status: %d\n", 988 ntohl(chunk->subh.data_hdr->tsn), 989 status); 990 sctp_outq_head_data(q, chunk); 991 goto sctp_flush_out; 992 break; 993 994 case SCTP_XMIT_OK: 995 break; 996 997 default: 998 BUG(); 999 } 1000 1001 /* BUG: We assume that the sctp_packet_transmit() 1002 * call below will succeed all the time and add the 1003 * chunk to the transmitted list and restart the 1004 * timers. 1005 * It is possible that the call can fail under OOM 1006 * conditions. 1007 * 1008 * Is this really a problem? Won't this behave 1009 * like a lost TSN? 1010 */ 1011 list_add_tail(&chunk->transmitted_list, 1012 &transport->transmitted); 1013 1014 sctp_transport_reset_timers(transport, start_timer-1); 1015 1016 q->empty = 0; 1017 1018 /* Only let one DATA chunk get bundled with a 1019 * COOKIE-ECHO chunk. 1020 */ 1021 if (packet->has_cookie_echo) 1022 goto sctp_flush_out; 1023 } 1024 break; 1025 1026 default: 1027 /* Do nothing. */ 1028 break; 1029 } 1030 1031 sctp_flush_out: 1032 1033 /* Before returning, examine all the transports touched in 1034 * this call. Right now, we bluntly force clear all the 1035 * transports. Things might change after we implement Nagle. 1036 * But such an examination is still required. 1037 * 1038 * --xguo 1039 */ 1040 while ((ltransport = sctp_list_dequeue(&transport_list)) != NULL ) { 1041 struct sctp_transport *t = list_entry(ltransport, 1042 struct sctp_transport, 1043 send_ready); 1044 packet = &t->packet; 1045 if (!sctp_packet_empty(packet)) 1046 error = sctp_packet_transmit(packet); 1047 } 1048 1049 return error; 1050 } 1051 1052 /* Update unack_data based on the incoming SACK chunk */ 1053 static void sctp_sack_update_unack_data(struct sctp_association *assoc, 1054 struct sctp_sackhdr *sack) 1055 { 1056 sctp_sack_variable_t *frags; 1057 __u16 unack_data; 1058 int i; 1059 1060 unack_data = assoc->next_tsn - assoc->ctsn_ack_point - 1; 1061 1062 frags = sack->variable; 1063 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); i++) { 1064 unack_data -= ((ntohs(frags[i].gab.end) - 1065 ntohs(frags[i].gab.start) + 1)); 1066 } 1067 1068 assoc->unack_data = unack_data; 1069 } 1070 1071 /* Return the highest new tsn that is acknowledged by the given SACK chunk. */ 1072 static __u32 sctp_highest_new_tsn(struct sctp_sackhdr *sack, 1073 struct sctp_association *asoc) 1074 { 1075 struct sctp_transport *transport; 1076 struct sctp_chunk *chunk; 1077 __u32 highest_new_tsn, tsn; 1078 struct list_head *transport_list = &asoc->peer.transport_addr_list; 1079 1080 highest_new_tsn = ntohl(sack->cum_tsn_ack); 1081 1082 list_for_each_entry(transport, transport_list, transports) { 1083 list_for_each_entry(chunk, &transport->transmitted, 1084 transmitted_list) { 1085 tsn = ntohl(chunk->subh.data_hdr->tsn); 1086 1087 if (!chunk->tsn_gap_acked && 1088 TSN_lt(highest_new_tsn, tsn) && 1089 sctp_acked(sack, tsn)) 1090 highest_new_tsn = tsn; 1091 } 1092 } 1093 1094 return highest_new_tsn; 1095 } 1096 1097 /* This is where we REALLY process a SACK. 1098 * 1099 * Process the SACK against the outqueue. Mostly, this just frees 1100 * things off the transmitted queue. 1101 */ 1102 int sctp_outq_sack(struct sctp_outq *q, struct sctp_sackhdr *sack) 1103 { 1104 struct sctp_association *asoc = q->asoc; 1105 struct sctp_transport *transport; 1106 struct sctp_chunk *tchunk = NULL; 1107 struct list_head *lchunk, *transport_list, *temp; 1108 sctp_sack_variable_t *frags = sack->variable; 1109 __u32 sack_ctsn, ctsn, tsn; 1110 __u32 highest_tsn, highest_new_tsn; 1111 __u32 sack_a_rwnd; 1112 unsigned outstanding; 1113 struct sctp_transport *primary = asoc->peer.primary_path; 1114 int count_of_newacks = 0; 1115 1116 /* Grab the association's destination address list. */ 1117 transport_list = &asoc->peer.transport_addr_list; 1118 1119 sack_ctsn = ntohl(sack->cum_tsn_ack); 1120 1121 /* 1122 * SFR-CACC algorithm: 1123 * On receipt of a SACK the sender SHOULD execute the 1124 * following statements. 1125 * 1126 * 1) If the cumulative ack in the SACK passes next tsn_at_change 1127 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be 1128 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for 1129 * all destinations. 1130 */ 1131 if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) { 1132 primary->cacc.changeover_active = 0; 1133 list_for_each_entry(transport, transport_list, 1134 transports) { 1135 transport->cacc.cycling_changeover = 0; 1136 } 1137 } 1138 1139 /* 1140 * SFR-CACC algorithm: 1141 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE 1142 * is set the receiver of the SACK MUST take the following actions: 1143 * 1144 * A) Initialize the cacc_saw_newack to 0 for all destination 1145 * addresses. 1146 */ 1147 if (sack->num_gap_ack_blocks && 1148 primary->cacc.changeover_active) { 1149 list_for_each_entry(transport, transport_list, transports) { 1150 transport->cacc.cacc_saw_newack = 0; 1151 } 1152 } 1153 1154 /* Get the highest TSN in the sack. */ 1155 highest_tsn = sack_ctsn; 1156 if (sack->num_gap_ack_blocks) 1157 highest_tsn += 1158 ntohs(frags[ntohs(sack->num_gap_ack_blocks) - 1].gab.end); 1159 1160 if (TSN_lt(asoc->highest_sacked, highest_tsn)) { 1161 highest_new_tsn = highest_tsn; 1162 asoc->highest_sacked = highest_tsn; 1163 } else { 1164 highest_new_tsn = sctp_highest_new_tsn(sack, asoc); 1165 } 1166 1167 /* Run through the retransmit queue. Credit bytes received 1168 * and free those chunks that we can. 1169 */ 1170 sctp_check_transmitted(q, &q->retransmit, NULL, sack, highest_new_tsn); 1171 sctp_mark_missing(q, &q->retransmit, NULL, highest_new_tsn, 0); 1172 1173 /* Run through the transmitted queue. 1174 * Credit bytes received and free those chunks which we can. 1175 * 1176 * This is a MASSIVE candidate for optimization. 1177 */ 1178 list_for_each_entry(transport, transport_list, transports) { 1179 sctp_check_transmitted(q, &transport->transmitted, 1180 transport, sack, highest_new_tsn); 1181 /* 1182 * SFR-CACC algorithm: 1183 * C) Let count_of_newacks be the number of 1184 * destinations for which cacc_saw_newack is set. 1185 */ 1186 if (transport->cacc.cacc_saw_newack) 1187 count_of_newacks ++; 1188 } 1189 1190 list_for_each_entry(transport, transport_list, transports) { 1191 sctp_mark_missing(q, &transport->transmitted, transport, 1192 highest_new_tsn, count_of_newacks); 1193 } 1194 1195 /* Move the Cumulative TSN Ack Point if appropriate. */ 1196 if (TSN_lt(asoc->ctsn_ack_point, sack_ctsn)) 1197 asoc->ctsn_ack_point = sack_ctsn; 1198 1199 /* Update unack_data field in the assoc. */ 1200 sctp_sack_update_unack_data(asoc, sack); 1201 1202 ctsn = asoc->ctsn_ack_point; 1203 1204 /* Throw away stuff rotting on the sack queue. */ 1205 list_for_each_safe(lchunk, temp, &q->sacked) { 1206 tchunk = list_entry(lchunk, struct sctp_chunk, 1207 transmitted_list); 1208 tsn = ntohl(tchunk->subh.data_hdr->tsn); 1209 if (TSN_lte(tsn, ctsn)) { 1210 list_del_init(&tchunk->transmitted_list); 1211 sctp_chunk_free(tchunk); 1212 } 1213 } 1214 1215 /* ii) Set rwnd equal to the newly received a_rwnd minus the 1216 * number of bytes still outstanding after processing the 1217 * Cumulative TSN Ack and the Gap Ack Blocks. 1218 */ 1219 1220 sack_a_rwnd = ntohl(sack->a_rwnd); 1221 outstanding = q->outstanding_bytes; 1222 1223 if (outstanding < sack_a_rwnd) 1224 sack_a_rwnd -= outstanding; 1225 else 1226 sack_a_rwnd = 0; 1227 1228 asoc->peer.rwnd = sack_a_rwnd; 1229 1230 sctp_generate_fwdtsn(q, sack_ctsn); 1231 1232 SCTP_DEBUG_PRINTK("%s: sack Cumulative TSN Ack is 0x%x.\n", 1233 __func__, sack_ctsn); 1234 SCTP_DEBUG_PRINTK("%s: Cumulative TSN Ack of association, " 1235 "%p is 0x%x. Adv peer ack point: 0x%x\n", 1236 __func__, asoc, ctsn, asoc->adv_peer_ack_point); 1237 1238 /* See if all chunks are acked. 1239 * Make sure the empty queue handler will get run later. 1240 */ 1241 q->empty = (list_empty(&q->out_chunk_list) && 1242 list_empty(&q->control_chunk_list) && 1243 list_empty(&q->retransmit)); 1244 if (!q->empty) 1245 goto finish; 1246 1247 list_for_each_entry(transport, transport_list, transports) { 1248 q->empty = q->empty && list_empty(&transport->transmitted); 1249 if (!q->empty) 1250 goto finish; 1251 } 1252 1253 SCTP_DEBUG_PRINTK("sack queue is empty.\n"); 1254 finish: 1255 return q->empty; 1256 } 1257 1258 /* Is the outqueue empty? */ 1259 int sctp_outq_is_empty(const struct sctp_outq *q) 1260 { 1261 return q->empty; 1262 } 1263 1264 /******************************************************************** 1265 * 2nd Level Abstractions 1266 ********************************************************************/ 1267 1268 /* Go through a transport's transmitted list or the association's retransmit 1269 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked. 1270 * The retransmit list will not have an associated transport. 1271 * 1272 * I added coherent debug information output. --xguo 1273 * 1274 * Instead of printing 'sacked' or 'kept' for each TSN on the 1275 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5. 1276 * KEPT TSN6-TSN7, etc. 1277 */ 1278 static void sctp_check_transmitted(struct sctp_outq *q, 1279 struct list_head *transmitted_queue, 1280 struct sctp_transport *transport, 1281 struct sctp_sackhdr *sack, 1282 __u32 highest_new_tsn_in_sack) 1283 { 1284 struct list_head *lchunk; 1285 struct sctp_chunk *tchunk; 1286 struct list_head tlist; 1287 __u32 tsn; 1288 __u32 sack_ctsn; 1289 __u32 rtt; 1290 __u8 restart_timer = 0; 1291 int bytes_acked = 0; 1292 1293 /* These state variables are for coherent debug output. --xguo */ 1294 1295 #if SCTP_DEBUG 1296 __u32 dbg_ack_tsn = 0; /* An ACKed TSN range starts here... */ 1297 __u32 dbg_last_ack_tsn = 0; /* ...and finishes here. */ 1298 __u32 dbg_kept_tsn = 0; /* An un-ACKed range starts here... */ 1299 __u32 dbg_last_kept_tsn = 0; /* ...and finishes here. */ 1300 1301 /* 0 : The last TSN was ACKed. 1302 * 1 : The last TSN was NOT ACKed (i.e. KEPT). 1303 * -1: We need to initialize. 1304 */ 1305 int dbg_prt_state = -1; 1306 #endif /* SCTP_DEBUG */ 1307 1308 sack_ctsn = ntohl(sack->cum_tsn_ack); 1309 1310 INIT_LIST_HEAD(&tlist); 1311 1312 /* The while loop will skip empty transmitted queues. */ 1313 while (NULL != (lchunk = sctp_list_dequeue(transmitted_queue))) { 1314 tchunk = list_entry(lchunk, struct sctp_chunk, 1315 transmitted_list); 1316 1317 if (sctp_chunk_abandoned(tchunk)) { 1318 /* Move the chunk to abandoned list. */ 1319 sctp_insert_list(&q->abandoned, lchunk); 1320 1321 /* If this chunk has not been acked, stop 1322 * considering it as 'outstanding'. 1323 */ 1324 if (!tchunk->tsn_gap_acked) { 1325 tchunk->transport->flight_size -= 1326 sctp_data_size(tchunk); 1327 q->outstanding_bytes -= sctp_data_size(tchunk); 1328 } 1329 continue; 1330 } 1331 1332 tsn = ntohl(tchunk->subh.data_hdr->tsn); 1333 if (sctp_acked(sack, tsn)) { 1334 /* If this queue is the retransmit queue, the 1335 * retransmit timer has already reclaimed 1336 * the outstanding bytes for this chunk, so only 1337 * count bytes associated with a transport. 1338 */ 1339 if (transport) { 1340 /* If this chunk is being used for RTT 1341 * measurement, calculate the RTT and update 1342 * the RTO using this value. 1343 * 1344 * 6.3.1 C5) Karn's algorithm: RTT measurements 1345 * MUST NOT be made using packets that were 1346 * retransmitted (and thus for which it is 1347 * ambiguous whether the reply was for the 1348 * first instance of the packet or a later 1349 * instance). 1350 */ 1351 if (!tchunk->tsn_gap_acked && 1352 !tchunk->resent && 1353 tchunk->rtt_in_progress) { 1354 tchunk->rtt_in_progress = 0; 1355 rtt = jiffies - tchunk->sent_at; 1356 sctp_transport_update_rto(transport, 1357 rtt); 1358 } 1359 } 1360 if (TSN_lte(tsn, sack_ctsn)) { 1361 /* RFC 2960 6.3.2 Retransmission Timer Rules 1362 * 1363 * R3) Whenever a SACK is received 1364 * that acknowledges the DATA chunk 1365 * with the earliest outstanding TSN 1366 * for that address, restart T3-rtx 1367 * timer for that address with its 1368 * current RTO. 1369 */ 1370 restart_timer = 1; 1371 1372 if (!tchunk->tsn_gap_acked) { 1373 tchunk->tsn_gap_acked = 1; 1374 bytes_acked += sctp_data_size(tchunk); 1375 /* 1376 * SFR-CACC algorithm: 1377 * 2) If the SACK contains gap acks 1378 * and the flag CHANGEOVER_ACTIVE is 1379 * set the receiver of the SACK MUST 1380 * take the following action: 1381 * 1382 * B) For each TSN t being acked that 1383 * has not been acked in any SACK so 1384 * far, set cacc_saw_newack to 1 for 1385 * the destination that the TSN was 1386 * sent to. 1387 */ 1388 if (transport && 1389 sack->num_gap_ack_blocks && 1390 q->asoc->peer.primary_path->cacc. 1391 changeover_active) 1392 transport->cacc.cacc_saw_newack 1393 = 1; 1394 } 1395 1396 list_add_tail(&tchunk->transmitted_list, 1397 &q->sacked); 1398 } else { 1399 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2 1400 * M2) Each time a SACK arrives reporting 1401 * 'Stray DATA chunk(s)' record the highest TSN 1402 * reported as newly acknowledged, call this 1403 * value 'HighestTSNinSack'. A newly 1404 * acknowledged DATA chunk is one not 1405 * previously acknowledged in a SACK. 1406 * 1407 * When the SCTP sender of data receives a SACK 1408 * chunk that acknowledges, for the first time, 1409 * the receipt of a DATA chunk, all the still 1410 * unacknowledged DATA chunks whose TSN is 1411 * older than that newly acknowledged DATA 1412 * chunk, are qualified as 'Stray DATA chunks'. 1413 */ 1414 if (!tchunk->tsn_gap_acked) { 1415 tchunk->tsn_gap_acked = 1; 1416 bytes_acked += sctp_data_size(tchunk); 1417 } 1418 list_add_tail(lchunk, &tlist); 1419 } 1420 1421 #if SCTP_DEBUG 1422 switch (dbg_prt_state) { 1423 case 0: /* last TSN was ACKed */ 1424 if (dbg_last_ack_tsn + 1 == tsn) { 1425 /* This TSN belongs to the 1426 * current ACK range. 1427 */ 1428 break; 1429 } 1430 1431 if (dbg_last_ack_tsn != dbg_ack_tsn) { 1432 /* Display the end of the 1433 * current range. 1434 */ 1435 SCTP_DEBUG_PRINTK("-%08x", 1436 dbg_last_ack_tsn); 1437 } 1438 1439 /* Start a new range. */ 1440 SCTP_DEBUG_PRINTK(",%08x", tsn); 1441 dbg_ack_tsn = tsn; 1442 break; 1443 1444 case 1: /* The last TSN was NOT ACKed. */ 1445 if (dbg_last_kept_tsn != dbg_kept_tsn) { 1446 /* Display the end of current range. */ 1447 SCTP_DEBUG_PRINTK("-%08x", 1448 dbg_last_kept_tsn); 1449 } 1450 1451 SCTP_DEBUG_PRINTK("\n"); 1452 1453 /* FALL THROUGH... */ 1454 default: 1455 /* This is the first-ever TSN we examined. */ 1456 /* Start a new range of ACK-ed TSNs. */ 1457 SCTP_DEBUG_PRINTK("ACKed: %08x", tsn); 1458 dbg_prt_state = 0; 1459 dbg_ack_tsn = tsn; 1460 } 1461 1462 dbg_last_ack_tsn = tsn; 1463 #endif /* SCTP_DEBUG */ 1464 1465 } else { 1466 if (tchunk->tsn_gap_acked) { 1467 SCTP_DEBUG_PRINTK("%s: Receiver reneged on " 1468 "data TSN: 0x%x\n", 1469 __func__, 1470 tsn); 1471 tchunk->tsn_gap_acked = 0; 1472 1473 bytes_acked -= sctp_data_size(tchunk); 1474 1475 /* RFC 2960 6.3.2 Retransmission Timer Rules 1476 * 1477 * R4) Whenever a SACK is received missing a 1478 * TSN that was previously acknowledged via a 1479 * Gap Ack Block, start T3-rtx for the 1480 * destination address to which the DATA 1481 * chunk was originally 1482 * transmitted if it is not already running. 1483 */ 1484 restart_timer = 1; 1485 } 1486 1487 list_add_tail(lchunk, &tlist); 1488 1489 #if SCTP_DEBUG 1490 /* See the above comments on ACK-ed TSNs. */ 1491 switch (dbg_prt_state) { 1492 case 1: 1493 if (dbg_last_kept_tsn + 1 == tsn) 1494 break; 1495 1496 if (dbg_last_kept_tsn != dbg_kept_tsn) 1497 SCTP_DEBUG_PRINTK("-%08x", 1498 dbg_last_kept_tsn); 1499 1500 SCTP_DEBUG_PRINTK(",%08x", tsn); 1501 dbg_kept_tsn = tsn; 1502 break; 1503 1504 case 0: 1505 if (dbg_last_ack_tsn != dbg_ack_tsn) 1506 SCTP_DEBUG_PRINTK("-%08x", 1507 dbg_last_ack_tsn); 1508 SCTP_DEBUG_PRINTK("\n"); 1509 1510 /* FALL THROUGH... */ 1511 default: 1512 SCTP_DEBUG_PRINTK("KEPT: %08x",tsn); 1513 dbg_prt_state = 1; 1514 dbg_kept_tsn = tsn; 1515 } 1516 1517 dbg_last_kept_tsn = tsn; 1518 #endif /* SCTP_DEBUG */ 1519 } 1520 } 1521 1522 #if SCTP_DEBUG 1523 /* Finish off the last range, displaying its ending TSN. */ 1524 switch (dbg_prt_state) { 1525 case 0: 1526 if (dbg_last_ack_tsn != dbg_ack_tsn) { 1527 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_ack_tsn); 1528 } else { 1529 SCTP_DEBUG_PRINTK("\n"); 1530 } 1531 break; 1532 1533 case 1: 1534 if (dbg_last_kept_tsn != dbg_kept_tsn) { 1535 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_kept_tsn); 1536 } else { 1537 SCTP_DEBUG_PRINTK("\n"); 1538 } 1539 } 1540 #endif /* SCTP_DEBUG */ 1541 if (transport) { 1542 if (bytes_acked) { 1543 /* 8.2. When an outstanding TSN is acknowledged, 1544 * the endpoint shall clear the error counter of 1545 * the destination transport address to which the 1546 * DATA chunk was last sent. 1547 * The association's overall error counter is 1548 * also cleared. 1549 */ 1550 transport->error_count = 0; 1551 transport->asoc->overall_error_count = 0; 1552 1553 /* Mark the destination transport address as 1554 * active if it is not so marked. 1555 */ 1556 if ((transport->state == SCTP_INACTIVE) || 1557 (transport->state == SCTP_UNCONFIRMED)) { 1558 sctp_assoc_control_transport( 1559 transport->asoc, 1560 transport, 1561 SCTP_TRANSPORT_UP, 1562 SCTP_RECEIVED_SACK); 1563 } 1564 1565 sctp_transport_raise_cwnd(transport, sack_ctsn, 1566 bytes_acked); 1567 1568 transport->flight_size -= bytes_acked; 1569 if (transport->flight_size == 0) 1570 transport->partial_bytes_acked = 0; 1571 q->outstanding_bytes -= bytes_acked; 1572 } else { 1573 /* RFC 2960 6.1, sctpimpguide-06 2.15.2 1574 * When a sender is doing zero window probing, it 1575 * should not timeout the association if it continues 1576 * to receive new packets from the receiver. The 1577 * reason is that the receiver MAY keep its window 1578 * closed for an indefinite time. 1579 * A sender is doing zero window probing when the 1580 * receiver's advertised window is zero, and there is 1581 * only one data chunk in flight to the receiver. 1582 */ 1583 if (!q->asoc->peer.rwnd && 1584 !list_empty(&tlist) && 1585 (sack_ctsn+2 == q->asoc->next_tsn)) { 1586 SCTP_DEBUG_PRINTK("%s: SACK received for zero " 1587 "window probe: %u\n", 1588 __func__, sack_ctsn); 1589 q->asoc->overall_error_count = 0; 1590 transport->error_count = 0; 1591 } 1592 } 1593 1594 /* RFC 2960 6.3.2 Retransmission Timer Rules 1595 * 1596 * R2) Whenever all outstanding data sent to an address have 1597 * been acknowledged, turn off the T3-rtx timer of that 1598 * address. 1599 */ 1600 if (!transport->flight_size) { 1601 if (timer_pending(&transport->T3_rtx_timer) && 1602 del_timer(&transport->T3_rtx_timer)) { 1603 sctp_transport_put(transport); 1604 } 1605 } else if (restart_timer) { 1606 if (!mod_timer(&transport->T3_rtx_timer, 1607 jiffies + transport->rto)) 1608 sctp_transport_hold(transport); 1609 } 1610 } 1611 1612 list_splice(&tlist, transmitted_queue); 1613 } 1614 1615 /* Mark chunks as missing and consequently may get retransmitted. */ 1616 static void sctp_mark_missing(struct sctp_outq *q, 1617 struct list_head *transmitted_queue, 1618 struct sctp_transport *transport, 1619 __u32 highest_new_tsn_in_sack, 1620 int count_of_newacks) 1621 { 1622 struct sctp_chunk *chunk; 1623 __u32 tsn; 1624 char do_fast_retransmit = 0; 1625 struct sctp_transport *primary = q->asoc->peer.primary_path; 1626 1627 list_for_each_entry(chunk, transmitted_queue, transmitted_list) { 1628 1629 tsn = ntohl(chunk->subh.data_hdr->tsn); 1630 1631 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all 1632 * 'Unacknowledged TSN's', if the TSN number of an 1633 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack' 1634 * value, increment the 'TSN.Missing.Report' count on that 1635 * chunk if it has NOT been fast retransmitted or marked for 1636 * fast retransmit already. 1637 */ 1638 if (!chunk->fast_retransmit && 1639 !chunk->tsn_gap_acked && 1640 TSN_lt(tsn, highest_new_tsn_in_sack)) { 1641 1642 /* SFR-CACC may require us to skip marking 1643 * this chunk as missing. 1644 */ 1645 if (!transport || !sctp_cacc_skip(primary, transport, 1646 count_of_newacks, tsn)) { 1647 chunk->tsn_missing_report++; 1648 1649 SCTP_DEBUG_PRINTK( 1650 "%s: TSN 0x%x missing counter: %d\n", 1651 __func__, tsn, 1652 chunk->tsn_missing_report); 1653 } 1654 } 1655 /* 1656 * M4) If any DATA chunk is found to have a 1657 * 'TSN.Missing.Report' 1658 * value larger than or equal to 3, mark that chunk for 1659 * retransmission and start the fast retransmit procedure. 1660 */ 1661 1662 if (chunk->tsn_missing_report >= 3) { 1663 chunk->fast_retransmit = 1; 1664 do_fast_retransmit = 1; 1665 } 1666 } 1667 1668 if (transport) { 1669 if (do_fast_retransmit) 1670 sctp_retransmit(q, transport, SCTP_RTXR_FAST_RTX); 1671 1672 SCTP_DEBUG_PRINTK("%s: transport: %p, cwnd: %d, " 1673 "ssthresh: %d, flight_size: %d, pba: %d\n", 1674 __func__, transport, transport->cwnd, 1675 transport->ssthresh, transport->flight_size, 1676 transport->partial_bytes_acked); 1677 } 1678 } 1679 1680 /* Is the given TSN acked by this packet? */ 1681 static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn) 1682 { 1683 int i; 1684 sctp_sack_variable_t *frags; 1685 __u16 gap; 1686 __u32 ctsn = ntohl(sack->cum_tsn_ack); 1687 1688 if (TSN_lte(tsn, ctsn)) 1689 goto pass; 1690 1691 /* 3.3.4 Selective Acknowledgement (SACK) (3): 1692 * 1693 * Gap Ack Blocks: 1694 * These fields contain the Gap Ack Blocks. They are repeated 1695 * for each Gap Ack Block up to the number of Gap Ack Blocks 1696 * defined in the Number of Gap Ack Blocks field. All DATA 1697 * chunks with TSNs greater than or equal to (Cumulative TSN 1698 * Ack + Gap Ack Block Start) and less than or equal to 1699 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack 1700 * Block are assumed to have been received correctly. 1701 */ 1702 1703 frags = sack->variable; 1704 gap = tsn - ctsn; 1705 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); ++i) { 1706 if (TSN_lte(ntohs(frags[i].gab.start), gap) && 1707 TSN_lte(gap, ntohs(frags[i].gab.end))) 1708 goto pass; 1709 } 1710 1711 return 0; 1712 pass: 1713 return 1; 1714 } 1715 1716 static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip *skiplist, 1717 int nskips, __be16 stream) 1718 { 1719 int i; 1720 1721 for (i = 0; i < nskips; i++) { 1722 if (skiplist[i].stream == stream) 1723 return i; 1724 } 1725 return i; 1726 } 1727 1728 /* Create and add a fwdtsn chunk to the outq's control queue if needed. */ 1729 static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 ctsn) 1730 { 1731 struct sctp_association *asoc = q->asoc; 1732 struct sctp_chunk *ftsn_chunk = NULL; 1733 struct sctp_fwdtsn_skip ftsn_skip_arr[10]; 1734 int nskips = 0; 1735 int skip_pos = 0; 1736 __u32 tsn; 1737 struct sctp_chunk *chunk; 1738 struct list_head *lchunk, *temp; 1739 1740 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the 1741 * received SACK. 1742 * 1743 * If (Advanced.Peer.Ack.Point < SackCumAck), then update 1744 * Advanced.Peer.Ack.Point to be equal to SackCumAck. 1745 */ 1746 if (TSN_lt(asoc->adv_peer_ack_point, ctsn)) 1747 asoc->adv_peer_ack_point = ctsn; 1748 1749 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point" 1750 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as 1751 * the chunk next in the out-queue space is marked as "abandoned" as 1752 * shown in the following example: 1753 * 1754 * Assuming that a SACK arrived with the Cumulative TSN ACK 102 1755 * and the Advanced.Peer.Ack.Point is updated to this value: 1756 * 1757 * out-queue at the end of ==> out-queue after Adv.Ack.Point 1758 * normal SACK processing local advancement 1759 * ... ... 1760 * Adv.Ack.Pt-> 102 acked 102 acked 1761 * 103 abandoned 103 abandoned 1762 * 104 abandoned Adv.Ack.P-> 104 abandoned 1763 * 105 105 1764 * 106 acked 106 acked 1765 * ... ... 1766 * 1767 * In this example, the data sender successfully advanced the 1768 * "Advanced.Peer.Ack.Point" from 102 to 104 locally. 1769 */ 1770 list_for_each_safe(lchunk, temp, &q->abandoned) { 1771 chunk = list_entry(lchunk, struct sctp_chunk, 1772 transmitted_list); 1773 tsn = ntohl(chunk->subh.data_hdr->tsn); 1774 1775 /* Remove any chunks in the abandoned queue that are acked by 1776 * the ctsn. 1777 */ 1778 if (TSN_lte(tsn, ctsn)) { 1779 list_del_init(lchunk); 1780 sctp_chunk_free(chunk); 1781 } else { 1782 if (TSN_lte(tsn, asoc->adv_peer_ack_point+1)) { 1783 asoc->adv_peer_ack_point = tsn; 1784 if (chunk->chunk_hdr->flags & 1785 SCTP_DATA_UNORDERED) 1786 continue; 1787 skip_pos = sctp_get_skip_pos(&ftsn_skip_arr[0], 1788 nskips, 1789 chunk->subh.data_hdr->stream); 1790 ftsn_skip_arr[skip_pos].stream = 1791 chunk->subh.data_hdr->stream; 1792 ftsn_skip_arr[skip_pos].ssn = 1793 chunk->subh.data_hdr->ssn; 1794 if (skip_pos == nskips) 1795 nskips++; 1796 if (nskips == 10) 1797 break; 1798 } else 1799 break; 1800 } 1801 } 1802 1803 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point" 1804 * is greater than the Cumulative TSN ACK carried in the received 1805 * SACK, the data sender MUST send the data receiver a FORWARD TSN 1806 * chunk containing the latest value of the 1807 * "Advanced.Peer.Ack.Point". 1808 * 1809 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD 1810 * list each stream and sequence number in the forwarded TSN. This 1811 * information will enable the receiver to easily find any 1812 * stranded TSN's waiting on stream reorder queues. Each stream 1813 * SHOULD only be reported once; this means that if multiple 1814 * abandoned messages occur in the same stream then only the 1815 * highest abandoned stream sequence number is reported. If the 1816 * total size of the FORWARD TSN does NOT fit in a single MTU then 1817 * the sender of the FORWARD TSN SHOULD lower the 1818 * Advanced.Peer.Ack.Point to the last TSN that will fit in a 1819 * single MTU. 1820 */ 1821 if (asoc->adv_peer_ack_point > ctsn) 1822 ftsn_chunk = sctp_make_fwdtsn(asoc, asoc->adv_peer_ack_point, 1823 nskips, &ftsn_skip_arr[0]); 1824 1825 if (ftsn_chunk) { 1826 list_add_tail(&ftsn_chunk->list, &q->control_chunk_list); 1827 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 1828 } 1829 } 1830