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 static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout); 75 76 /* Add data to the front of the queue. */ 77 static inline void sctp_outq_head_data(struct sctp_outq *q, 78 struct sctp_chunk *ch) 79 { 80 list_add(&ch->list, &q->out_chunk_list); 81 q->out_qlen += ch->skb->len; 82 return; 83 } 84 85 /* Take data from the front of the queue. */ 86 static inline struct sctp_chunk *sctp_outq_dequeue_data(struct sctp_outq *q) 87 { 88 struct sctp_chunk *ch = NULL; 89 90 if (!list_empty(&q->out_chunk_list)) { 91 struct list_head *entry = q->out_chunk_list.next; 92 93 ch = list_entry(entry, struct sctp_chunk, list); 94 list_del_init(entry); 95 q->out_qlen -= ch->skb->len; 96 } 97 return ch; 98 } 99 /* Add data chunk to the end of the queue. */ 100 static inline void sctp_outq_tail_data(struct sctp_outq *q, 101 struct sctp_chunk *ch) 102 { 103 list_add_tail(&ch->list, &q->out_chunk_list); 104 q->out_qlen += ch->skb->len; 105 return; 106 } 107 108 /* 109 * SFR-CACC algorithm: 110 * D) If count_of_newacks is greater than or equal to 2 111 * and t was not sent to the current primary then the 112 * sender MUST NOT increment missing report count for t. 113 */ 114 static inline int sctp_cacc_skip_3_1_d(struct sctp_transport *primary, 115 struct sctp_transport *transport, 116 int count_of_newacks) 117 { 118 if (count_of_newacks >=2 && transport != primary) 119 return 1; 120 return 0; 121 } 122 123 /* 124 * SFR-CACC algorithm: 125 * F) If count_of_newacks is less than 2, let d be the 126 * destination to which t was sent. If cacc_saw_newack 127 * is 0 for destination d, then the sender MUST NOT 128 * increment missing report count for t. 129 */ 130 static inline int sctp_cacc_skip_3_1_f(struct sctp_transport *transport, 131 int count_of_newacks) 132 { 133 if (count_of_newacks < 2 && !transport->cacc.cacc_saw_newack) 134 return 1; 135 return 0; 136 } 137 138 /* 139 * SFR-CACC algorithm: 140 * 3.1) If CYCLING_CHANGEOVER is 0, the sender SHOULD 141 * execute steps C, D, F. 142 * 143 * C has been implemented in sctp_outq_sack 144 */ 145 static inline int sctp_cacc_skip_3_1(struct sctp_transport *primary, 146 struct sctp_transport *transport, 147 int count_of_newacks) 148 { 149 if (!primary->cacc.cycling_changeover) { 150 if (sctp_cacc_skip_3_1_d(primary, transport, count_of_newacks)) 151 return 1; 152 if (sctp_cacc_skip_3_1_f(transport, count_of_newacks)) 153 return 1; 154 return 0; 155 } 156 return 0; 157 } 158 159 /* 160 * SFR-CACC algorithm: 161 * 3.2) Else if CYCLING_CHANGEOVER is 1, and t is less 162 * than next_tsn_at_change of the current primary, then 163 * the sender MUST NOT increment missing report count 164 * for t. 165 */ 166 static inline int sctp_cacc_skip_3_2(struct sctp_transport *primary, __u32 tsn) 167 { 168 if (primary->cacc.cycling_changeover && 169 TSN_lt(tsn, primary->cacc.next_tsn_at_change)) 170 return 1; 171 return 0; 172 } 173 174 /* 175 * SFR-CACC algorithm: 176 * 3) If the missing report count for TSN t is to be 177 * incremented according to [RFC2960] and 178 * [SCTP_STEWART-2002], and CHANGEOVER_ACTIVE is set, 179 * then the sender MUST futher execute steps 3.1 and 180 * 3.2 to determine if the missing report count for 181 * TSN t SHOULD NOT be incremented. 182 * 183 * 3.3) If 3.1 and 3.2 do not dictate that the missing 184 * report count for t should not be incremented, then 185 * the sender SOULD increment missing report count for 186 * t (according to [RFC2960] and [SCTP_STEWART_2002]). 187 */ 188 static inline int sctp_cacc_skip(struct sctp_transport *primary, 189 struct sctp_transport *transport, 190 int count_of_newacks, 191 __u32 tsn) 192 { 193 if (primary->cacc.changeover_active && 194 (sctp_cacc_skip_3_1(primary, transport, count_of_newacks) 195 || sctp_cacc_skip_3_2(primary, tsn))) 196 return 1; 197 return 0; 198 } 199 200 /* Initialize an existing sctp_outq. This does the boring stuff. 201 * You still need to define handlers if you really want to DO 202 * something with this structure... 203 */ 204 void sctp_outq_init(struct sctp_association *asoc, struct sctp_outq *q) 205 { 206 q->asoc = asoc; 207 INIT_LIST_HEAD(&q->out_chunk_list); 208 INIT_LIST_HEAD(&q->control_chunk_list); 209 INIT_LIST_HEAD(&q->retransmit); 210 INIT_LIST_HEAD(&q->sacked); 211 INIT_LIST_HEAD(&q->abandoned); 212 213 q->fast_rtx = 0; 214 q->outstanding_bytes = 0; 215 q->empty = 1; 216 q->cork = 0; 217 218 q->malloced = 0; 219 q->out_qlen = 0; 220 } 221 222 /* Free the outqueue structure and any related pending chunks. 223 */ 224 void sctp_outq_teardown(struct sctp_outq *q) 225 { 226 struct sctp_transport *transport; 227 struct list_head *lchunk, *temp; 228 struct sctp_chunk *chunk, *tmp; 229 230 /* Throw away unacknowledged chunks. */ 231 list_for_each_entry(transport, &q->asoc->peer.transport_addr_list, 232 transports) { 233 while ((lchunk = sctp_list_dequeue(&transport->transmitted)) != NULL) { 234 chunk = list_entry(lchunk, struct sctp_chunk, 235 transmitted_list); 236 /* Mark as part of a failed message. */ 237 sctp_chunk_fail(chunk, q->error); 238 sctp_chunk_free(chunk); 239 } 240 } 241 242 /* Throw away chunks that have been gap ACKed. */ 243 list_for_each_safe(lchunk, temp, &q->sacked) { 244 list_del_init(lchunk); 245 chunk = list_entry(lchunk, struct sctp_chunk, 246 transmitted_list); 247 sctp_chunk_fail(chunk, q->error); 248 sctp_chunk_free(chunk); 249 } 250 251 /* Throw away any chunks in the retransmit queue. */ 252 list_for_each_safe(lchunk, temp, &q->retransmit) { 253 list_del_init(lchunk); 254 chunk = list_entry(lchunk, struct sctp_chunk, 255 transmitted_list); 256 sctp_chunk_fail(chunk, q->error); 257 sctp_chunk_free(chunk); 258 } 259 260 /* Throw away any chunks that are in the abandoned queue. */ 261 list_for_each_safe(lchunk, temp, &q->abandoned) { 262 list_del_init(lchunk); 263 chunk = list_entry(lchunk, struct sctp_chunk, 264 transmitted_list); 265 sctp_chunk_fail(chunk, q->error); 266 sctp_chunk_free(chunk); 267 } 268 269 /* Throw away any leftover data chunks. */ 270 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) { 271 272 /* Mark as send failure. */ 273 sctp_chunk_fail(chunk, q->error); 274 sctp_chunk_free(chunk); 275 } 276 277 q->error = 0; 278 279 /* Throw away any leftover control chunks. */ 280 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) { 281 list_del_init(&chunk->list); 282 sctp_chunk_free(chunk); 283 } 284 } 285 286 /* Free the outqueue structure and any related pending chunks. */ 287 void sctp_outq_free(struct sctp_outq *q) 288 { 289 /* Throw away leftover chunks. */ 290 sctp_outq_teardown(q); 291 292 /* If we were kmalloc()'d, free the memory. */ 293 if (q->malloced) 294 kfree(q); 295 } 296 297 /* Put a new chunk in an sctp_outq. */ 298 int sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk) 299 { 300 int error = 0; 301 302 SCTP_DEBUG_PRINTK("sctp_outq_tail(%p, %p[%s])\n", 303 q, chunk, chunk && chunk->chunk_hdr ? 304 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) 305 : "Illegal Chunk"); 306 307 /* If it is data, queue it up, otherwise, send it 308 * immediately. 309 */ 310 if (SCTP_CID_DATA == chunk->chunk_hdr->type) { 311 /* Is it OK to queue data chunks? */ 312 /* From 9. Termination of Association 313 * 314 * When either endpoint performs a shutdown, the 315 * association on each peer will stop accepting new 316 * data from its user and only deliver data in queue 317 * at the time of sending or receiving the SHUTDOWN 318 * chunk. 319 */ 320 switch (q->asoc->state) { 321 case SCTP_STATE_EMPTY: 322 case SCTP_STATE_CLOSED: 323 case SCTP_STATE_SHUTDOWN_PENDING: 324 case SCTP_STATE_SHUTDOWN_SENT: 325 case SCTP_STATE_SHUTDOWN_RECEIVED: 326 case SCTP_STATE_SHUTDOWN_ACK_SENT: 327 /* Cannot send after transport endpoint shutdown */ 328 error = -ESHUTDOWN; 329 break; 330 331 default: 332 SCTP_DEBUG_PRINTK("outqueueing (%p, %p[%s])\n", 333 q, chunk, chunk && chunk->chunk_hdr ? 334 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) 335 : "Illegal Chunk"); 336 337 sctp_outq_tail_data(q, chunk); 338 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) 339 SCTP_INC_STATS(SCTP_MIB_OUTUNORDERCHUNKS); 340 else 341 SCTP_INC_STATS(SCTP_MIB_OUTORDERCHUNKS); 342 q->empty = 0; 343 break; 344 } 345 } else { 346 list_add_tail(&chunk->list, &q->control_chunk_list); 347 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 348 } 349 350 if (error < 0) 351 return error; 352 353 if (!q->cork) 354 error = sctp_outq_flush(q, 0); 355 356 return error; 357 } 358 359 /* Insert a chunk into the sorted list based on the TSNs. The retransmit list 360 * and the abandoned list are in ascending order. 361 */ 362 static void sctp_insert_list(struct list_head *head, struct list_head *new) 363 { 364 struct list_head *pos; 365 struct sctp_chunk *nchunk, *lchunk; 366 __u32 ntsn, ltsn; 367 int done = 0; 368 369 nchunk = list_entry(new, struct sctp_chunk, transmitted_list); 370 ntsn = ntohl(nchunk->subh.data_hdr->tsn); 371 372 list_for_each(pos, head) { 373 lchunk = list_entry(pos, struct sctp_chunk, transmitted_list); 374 ltsn = ntohl(lchunk->subh.data_hdr->tsn); 375 if (TSN_lt(ntsn, ltsn)) { 376 list_add(new, pos->prev); 377 done = 1; 378 break; 379 } 380 } 381 if (!done) 382 list_add_tail(new, head); 383 } 384 385 /* Mark all the eligible packets on a transport for retransmission. */ 386 void sctp_retransmit_mark(struct sctp_outq *q, 387 struct sctp_transport *transport, 388 __u8 reason) 389 { 390 struct list_head *lchunk, *ltemp; 391 struct sctp_chunk *chunk; 392 393 /* Walk through the specified transmitted queue. */ 394 list_for_each_safe(lchunk, ltemp, &transport->transmitted) { 395 chunk = list_entry(lchunk, struct sctp_chunk, 396 transmitted_list); 397 398 /* If the chunk is abandoned, move it to abandoned list. */ 399 if (sctp_chunk_abandoned(chunk)) { 400 list_del_init(lchunk); 401 sctp_insert_list(&q->abandoned, lchunk); 402 403 /* If this chunk has not been previousely acked, 404 * stop considering it 'outstanding'. Our peer 405 * will most likely never see it since it will 406 * not be retransmitted 407 */ 408 if (!chunk->tsn_gap_acked) { 409 chunk->transport->flight_size -= 410 sctp_data_size(chunk); 411 q->outstanding_bytes -= sctp_data_size(chunk); 412 q->asoc->peer.rwnd += (sctp_data_size(chunk) + 413 sizeof(struct sk_buff)); 414 } 415 continue; 416 } 417 418 /* If we are doing retransmission due to a timeout or pmtu 419 * discovery, only the chunks that are not yet acked should 420 * be added to the retransmit queue. 421 */ 422 if ((reason == SCTP_RTXR_FAST_RTX && 423 (chunk->fast_retransmit == SCTP_NEED_FRTX)) || 424 (reason != SCTP_RTXR_FAST_RTX && !chunk->tsn_gap_acked)) { 425 /* If this chunk was sent less then 1 rto ago, do not 426 * retransmit this chunk, but give the peer time 427 * to acknowlege it. Do this only when 428 * retransmitting due to T3 timeout. 429 */ 430 if (reason == SCTP_RTXR_T3_RTX && 431 (jiffies - chunk->sent_at) < transport->last_rto) 432 continue; 433 434 /* RFC 2960 6.2.1 Processing a Received SACK 435 * 436 * C) Any time a DATA chunk is marked for 437 * retransmission (via either T3-rtx timer expiration 438 * (Section 6.3.3) or via fast retransmit 439 * (Section 7.2.4)), add the data size of those 440 * chunks to the rwnd. 441 */ 442 q->asoc->peer.rwnd += (sctp_data_size(chunk) + 443 sizeof(struct sk_buff)); 444 q->outstanding_bytes -= sctp_data_size(chunk); 445 transport->flight_size -= sctp_data_size(chunk); 446 447 /* sctpimpguide-05 Section 2.8.2 448 * M5) If a T3-rtx timer expires, the 449 * 'TSN.Missing.Report' of all affected TSNs is set 450 * to 0. 451 */ 452 chunk->tsn_missing_report = 0; 453 454 /* If a chunk that is being used for RTT measurement 455 * has to be retransmitted, we cannot use this chunk 456 * anymore for RTT measurements. Reset rto_pending so 457 * that a new RTT measurement is started when a new 458 * data chunk is sent. 459 */ 460 if (chunk->rtt_in_progress) { 461 chunk->rtt_in_progress = 0; 462 transport->rto_pending = 0; 463 } 464 465 /* Move the chunk to the retransmit queue. The chunks 466 * on the retransmit queue are always kept in order. 467 */ 468 list_del_init(lchunk); 469 sctp_insert_list(&q->retransmit, lchunk); 470 } 471 } 472 473 SCTP_DEBUG_PRINTK("%s: transport: %p, reason: %d, " 474 "cwnd: %d, ssthresh: %d, flight_size: %d, " 475 "pba: %d\n", __func__, 476 transport, reason, 477 transport->cwnd, transport->ssthresh, 478 transport->flight_size, 479 transport->partial_bytes_acked); 480 481 } 482 483 /* Mark all the eligible packets on a transport for retransmission and force 484 * one packet out. 485 */ 486 void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport, 487 sctp_retransmit_reason_t reason) 488 { 489 int error = 0; 490 491 switch(reason) { 492 case SCTP_RTXR_T3_RTX: 493 SCTP_INC_STATS(SCTP_MIB_T3_RETRANSMITS); 494 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_T3_RTX); 495 /* Update the retran path if the T3-rtx timer has expired for 496 * the current retran path. 497 */ 498 if (transport == transport->asoc->peer.retran_path) 499 sctp_assoc_update_retran_path(transport->asoc); 500 transport->asoc->rtx_data_chunks += 501 transport->asoc->unack_data; 502 break; 503 case SCTP_RTXR_FAST_RTX: 504 SCTP_INC_STATS(SCTP_MIB_FAST_RETRANSMITS); 505 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_FAST_RTX); 506 q->fast_rtx = 1; 507 break; 508 case SCTP_RTXR_PMTUD: 509 SCTP_INC_STATS(SCTP_MIB_PMTUD_RETRANSMITS); 510 break; 511 case SCTP_RTXR_T1_RTX: 512 SCTP_INC_STATS(SCTP_MIB_T1_RETRANSMITS); 513 transport->asoc->init_retries++; 514 break; 515 default: 516 BUG(); 517 } 518 519 sctp_retransmit_mark(q, transport, reason); 520 521 /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination, 522 * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by 523 * following the procedures outlined in C1 - C5. 524 */ 525 if (reason == SCTP_RTXR_T3_RTX) 526 sctp_generate_fwdtsn(q, q->asoc->ctsn_ack_point); 527 528 /* Flush the queues only on timeout, since fast_rtx is only 529 * triggered during sack processing and the queue 530 * will be flushed at the end. 531 */ 532 if (reason != SCTP_RTXR_FAST_RTX) 533 error = sctp_outq_flush(q, /* rtx_timeout */ 1); 534 535 if (error) 536 q->asoc->base.sk->sk_err = -error; 537 } 538 539 /* 540 * Transmit DATA chunks on the retransmit queue. Upon return from 541 * sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which 542 * need to be transmitted by the caller. 543 * We assume that pkt->transport has already been set. 544 * 545 * The return value is a normal kernel error return value. 546 */ 547 static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt, 548 int rtx_timeout, int *start_timer) 549 { 550 struct list_head *lqueue; 551 struct sctp_transport *transport = pkt->transport; 552 sctp_xmit_t status; 553 struct sctp_chunk *chunk, *chunk1; 554 struct sctp_association *asoc; 555 int fast_rtx; 556 int error = 0; 557 int timer = 0; 558 int done = 0; 559 560 asoc = q->asoc; 561 lqueue = &q->retransmit; 562 fast_rtx = q->fast_rtx; 563 564 /* This loop handles time-out retransmissions, fast retransmissions, 565 * and retransmissions due to opening of whindow. 566 * 567 * RFC 2960 6.3.3 Handle T3-rtx Expiration 568 * 569 * E3) Determine how many of the earliest (i.e., lowest TSN) 570 * outstanding DATA chunks for the address for which the 571 * T3-rtx has expired will fit into a single packet, subject 572 * to the MTU constraint for the path corresponding to the 573 * destination transport address to which the retransmission 574 * is being sent (this may be different from the address for 575 * which the timer expires [see Section 6.4]). Call this value 576 * K. Bundle and retransmit those K DATA chunks in a single 577 * packet to the destination endpoint. 578 * 579 * [Just to be painfully clear, if we are retransmitting 580 * because a timeout just happened, we should send only ONE 581 * packet of retransmitted data.] 582 * 583 * For fast retransmissions we also send only ONE packet. However, 584 * if we are just flushing the queue due to open window, we'll 585 * try to send as much as possible. 586 */ 587 list_for_each_entry_safe(chunk, chunk1, lqueue, transmitted_list) { 588 589 /* Make sure that Gap Acked TSNs are not retransmitted. A 590 * simple approach is just to move such TSNs out of the 591 * way and into a 'transmitted' queue and skip to the 592 * next chunk. 593 */ 594 if (chunk->tsn_gap_acked) { 595 list_del(&chunk->transmitted_list); 596 list_add_tail(&chunk->transmitted_list, 597 &transport->transmitted); 598 continue; 599 } 600 601 /* If we are doing fast retransmit, ignore non-fast_rtransmit 602 * chunks 603 */ 604 if (fast_rtx && !chunk->fast_retransmit) 605 continue; 606 607 /* Attempt to append this chunk to the packet. */ 608 status = sctp_packet_append_chunk(pkt, chunk); 609 610 switch (status) { 611 case SCTP_XMIT_PMTU_FULL: 612 /* Send this packet. */ 613 error = sctp_packet_transmit(pkt); 614 615 /* If we are retransmitting, we should only 616 * send a single packet. 617 */ 618 if (rtx_timeout || fast_rtx) 619 done = 1; 620 621 /* Bundle next chunk in the next round. */ 622 break; 623 624 case SCTP_XMIT_RWND_FULL: 625 /* Send this packet. */ 626 error = sctp_packet_transmit(pkt); 627 628 /* Stop sending DATA as there is no more room 629 * at the receiver. 630 */ 631 done = 1; 632 break; 633 634 case SCTP_XMIT_NAGLE_DELAY: 635 /* Send this packet. */ 636 error = sctp_packet_transmit(pkt); 637 638 /* Stop sending DATA because of nagle delay. */ 639 done = 1; 640 break; 641 642 default: 643 /* The append was successful, so add this chunk to 644 * the transmitted list. 645 */ 646 list_del(&chunk->transmitted_list); 647 list_add_tail(&chunk->transmitted_list, 648 &transport->transmitted); 649 650 /* Mark the chunk as ineligible for fast retransmit 651 * after it is retransmitted. 652 */ 653 if (chunk->fast_retransmit == SCTP_NEED_FRTX) 654 chunk->fast_retransmit = SCTP_DONT_FRTX; 655 656 /* Force start T3-rtx timer when fast retransmitting 657 * the earliest outstanding TSN 658 */ 659 if (!timer && fast_rtx && 660 ntohl(chunk->subh.data_hdr->tsn) == 661 asoc->ctsn_ack_point + 1) 662 timer = 2; 663 664 q->empty = 0; 665 break; 666 } 667 668 /* Set the timer if there were no errors */ 669 if (!error && !timer) 670 timer = 1; 671 672 if (done) 673 break; 674 } 675 676 /* If we are here due to a retransmit timeout or a fast 677 * retransmit and if there are any chunks left in the retransmit 678 * queue that could not fit in the PMTU sized packet, they need 679 * to be marked as ineligible for a subsequent fast retransmit. 680 */ 681 if (rtx_timeout || fast_rtx) { 682 list_for_each_entry(chunk1, lqueue, transmitted_list) { 683 if (chunk1->fast_retransmit == SCTP_NEED_FRTX) 684 chunk1->fast_retransmit = SCTP_DONT_FRTX; 685 } 686 } 687 688 *start_timer = timer; 689 690 /* Clear fast retransmit hint */ 691 if (fast_rtx) 692 q->fast_rtx = 0; 693 694 return error; 695 } 696 697 /* Cork the outqueue so queued chunks are really queued. */ 698 int sctp_outq_uncork(struct sctp_outq *q) 699 { 700 int error = 0; 701 if (q->cork) 702 q->cork = 0; 703 error = sctp_outq_flush(q, 0); 704 return error; 705 } 706 707 708 /* 709 * Try to flush an outqueue. 710 * 711 * Description: Send everything in q which we legally can, subject to 712 * congestion limitations. 713 * * Note: This function can be called from multiple contexts so appropriate 714 * locking concerns must be made. Today we use the sock lock to protect 715 * this function. 716 */ 717 static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout) 718 { 719 struct sctp_packet *packet; 720 struct sctp_packet singleton; 721 struct sctp_association *asoc = q->asoc; 722 __u16 sport = asoc->base.bind_addr.port; 723 __u16 dport = asoc->peer.port; 724 __u32 vtag = asoc->peer.i.init_tag; 725 struct sctp_transport *transport = NULL; 726 struct sctp_transport *new_transport; 727 struct sctp_chunk *chunk, *tmp; 728 sctp_xmit_t status; 729 int error = 0; 730 int start_timer = 0; 731 int one_packet = 0; 732 733 /* These transports have chunks to send. */ 734 struct list_head transport_list; 735 struct list_head *ltransport; 736 737 INIT_LIST_HEAD(&transport_list); 738 packet = NULL; 739 740 /* 741 * 6.10 Bundling 742 * ... 743 * When bundling control chunks with DATA chunks, an 744 * endpoint MUST place control chunks first in the outbound 745 * SCTP packet. The transmitter MUST transmit DATA chunks 746 * within a SCTP packet in increasing order of TSN. 747 * ... 748 */ 749 750 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) { 751 list_del_init(&chunk->list); 752 753 /* Pick the right transport to use. */ 754 new_transport = chunk->transport; 755 756 if (!new_transport) { 757 /* 758 * If we have a prior transport pointer, see if 759 * the destination address of the chunk 760 * matches the destination address of the 761 * current transport. If not a match, then 762 * try to look up the transport with a given 763 * destination address. We do this because 764 * after processing ASCONFs, we may have new 765 * transports created. 766 */ 767 if (transport && 768 sctp_cmp_addr_exact(&chunk->dest, 769 &transport->ipaddr)) 770 new_transport = transport; 771 else 772 new_transport = sctp_assoc_lookup_paddr(asoc, 773 &chunk->dest); 774 775 /* if we still don't have a new transport, then 776 * use the current active path. 777 */ 778 if (!new_transport) 779 new_transport = asoc->peer.active_path; 780 } else if ((new_transport->state == SCTP_INACTIVE) || 781 (new_transport->state == SCTP_UNCONFIRMED)) { 782 /* If the chunk is Heartbeat or Heartbeat Ack, 783 * send it to chunk->transport, even if it's 784 * inactive. 785 * 786 * 3.3.6 Heartbeat Acknowledgement: 787 * ... 788 * A HEARTBEAT ACK is always sent to the source IP 789 * address of the IP datagram containing the 790 * HEARTBEAT chunk to which this ack is responding. 791 * ... 792 * 793 * ASCONF_ACKs also must be sent to the source. 794 */ 795 if (chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT && 796 chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT_ACK && 797 chunk->chunk_hdr->type != SCTP_CID_ASCONF_ACK) 798 new_transport = asoc->peer.active_path; 799 } 800 801 /* Are we switching transports? 802 * Take care of transport locks. 803 */ 804 if (new_transport != transport) { 805 transport = new_transport; 806 if (list_empty(&transport->send_ready)) { 807 list_add_tail(&transport->send_ready, 808 &transport_list); 809 } 810 packet = &transport->packet; 811 sctp_packet_config(packet, vtag, 812 asoc->peer.ecn_capable); 813 } 814 815 switch (chunk->chunk_hdr->type) { 816 /* 817 * 6.10 Bundling 818 * ... 819 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN 820 * COMPLETE with any other chunks. [Send them immediately.] 821 */ 822 case SCTP_CID_INIT: 823 case SCTP_CID_INIT_ACK: 824 case SCTP_CID_SHUTDOWN_COMPLETE: 825 sctp_packet_init(&singleton, transport, sport, dport); 826 sctp_packet_config(&singleton, vtag, 0); 827 sctp_packet_append_chunk(&singleton, chunk); 828 error = sctp_packet_transmit(&singleton); 829 if (error < 0) 830 return error; 831 break; 832 833 case SCTP_CID_ABORT: 834 if (sctp_test_T_bit(chunk)) { 835 packet->vtag = asoc->c.my_vtag; 836 } 837 /* The following chunks are "response" chunks, i.e. 838 * they are generated in response to something we 839 * received. If we are sending these, then we can 840 * send only 1 packet containing these chunks. 841 */ 842 case SCTP_CID_HEARTBEAT_ACK: 843 case SCTP_CID_SHUTDOWN_ACK: 844 case SCTP_CID_COOKIE_ACK: 845 case SCTP_CID_COOKIE_ECHO: 846 case SCTP_CID_ERROR: 847 case SCTP_CID_ECN_CWR: 848 case SCTP_CID_ASCONF_ACK: 849 one_packet = 1; 850 /* Fall throught */ 851 852 case SCTP_CID_SACK: 853 case SCTP_CID_HEARTBEAT: 854 case SCTP_CID_SHUTDOWN: 855 case SCTP_CID_ECN_ECNE: 856 case SCTP_CID_ASCONF: 857 case SCTP_CID_FWD_TSN: 858 status = sctp_packet_transmit_chunk(packet, chunk, 859 one_packet); 860 if (status != SCTP_XMIT_OK) { 861 /* put the chunk back */ 862 list_add(&chunk->list, &q->control_chunk_list); 863 } 864 break; 865 866 default: 867 /* We built a chunk with an illegal type! */ 868 BUG(); 869 } 870 } 871 872 /* Is it OK to send data chunks? */ 873 switch (asoc->state) { 874 case SCTP_STATE_COOKIE_ECHOED: 875 /* Only allow bundling when this packet has a COOKIE-ECHO 876 * chunk. 877 */ 878 if (!packet || !packet->has_cookie_echo) 879 break; 880 881 /* fallthru */ 882 case SCTP_STATE_ESTABLISHED: 883 case SCTP_STATE_SHUTDOWN_PENDING: 884 case SCTP_STATE_SHUTDOWN_RECEIVED: 885 /* 886 * RFC 2960 6.1 Transmission of DATA Chunks 887 * 888 * C) When the time comes for the sender to transmit, 889 * before sending new DATA chunks, the sender MUST 890 * first transmit any outstanding DATA chunks which 891 * are marked for retransmission (limited by the 892 * current cwnd). 893 */ 894 if (!list_empty(&q->retransmit)) { 895 if (transport == asoc->peer.retran_path) 896 goto retran; 897 898 /* Switch transports & prepare the packet. */ 899 900 transport = asoc->peer.retran_path; 901 902 if (list_empty(&transport->send_ready)) { 903 list_add_tail(&transport->send_ready, 904 &transport_list); 905 } 906 907 packet = &transport->packet; 908 sctp_packet_config(packet, vtag, 909 asoc->peer.ecn_capable); 910 retran: 911 error = sctp_outq_flush_rtx(q, packet, 912 rtx_timeout, &start_timer); 913 914 if (start_timer) 915 sctp_transport_reset_timers(transport, 916 start_timer-1); 917 918 /* This can happen on COOKIE-ECHO resend. Only 919 * one chunk can get bundled with a COOKIE-ECHO. 920 */ 921 if (packet->has_cookie_echo) 922 goto sctp_flush_out; 923 924 /* Don't send new data if there is still data 925 * waiting to retransmit. 926 */ 927 if (!list_empty(&q->retransmit)) 928 goto sctp_flush_out; 929 } 930 931 /* Finally, transmit new packets. */ 932 start_timer = 0; 933 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) { 934 /* RFC 2960 6.5 Every DATA chunk MUST carry a valid 935 * stream identifier. 936 */ 937 if (chunk->sinfo.sinfo_stream >= 938 asoc->c.sinit_num_ostreams) { 939 940 /* Mark as failed send. */ 941 sctp_chunk_fail(chunk, SCTP_ERROR_INV_STRM); 942 sctp_chunk_free(chunk); 943 continue; 944 } 945 946 /* Has this chunk expired? */ 947 if (sctp_chunk_abandoned(chunk)) { 948 sctp_chunk_fail(chunk, 0); 949 sctp_chunk_free(chunk); 950 continue; 951 } 952 953 /* If there is a specified transport, use it. 954 * Otherwise, we want to use the active path. 955 */ 956 new_transport = chunk->transport; 957 if (!new_transport || 958 ((new_transport->state == SCTP_INACTIVE) || 959 (new_transport->state == SCTP_UNCONFIRMED))) 960 new_transport = asoc->peer.active_path; 961 962 /* Change packets if necessary. */ 963 if (new_transport != transport) { 964 transport = new_transport; 965 966 /* Schedule to have this transport's 967 * packet flushed. 968 */ 969 if (list_empty(&transport->send_ready)) { 970 list_add_tail(&transport->send_ready, 971 &transport_list); 972 } 973 974 packet = &transport->packet; 975 sctp_packet_config(packet, vtag, 976 asoc->peer.ecn_capable); 977 } 978 979 SCTP_DEBUG_PRINTK("sctp_outq_flush(%p, %p[%s]), ", 980 q, chunk, 981 chunk && chunk->chunk_hdr ? 982 sctp_cname(SCTP_ST_CHUNK( 983 chunk->chunk_hdr->type)) 984 : "Illegal Chunk"); 985 986 SCTP_DEBUG_PRINTK("TX TSN 0x%x skb->head " 987 "%p skb->users %d.\n", 988 ntohl(chunk->subh.data_hdr->tsn), 989 chunk->skb ?chunk->skb->head : NULL, 990 chunk->skb ? 991 atomic_read(&chunk->skb->users) : -1); 992 993 /* Add the chunk to the packet. */ 994 status = sctp_packet_transmit_chunk(packet, chunk, 0); 995 996 switch (status) { 997 case SCTP_XMIT_PMTU_FULL: 998 case SCTP_XMIT_RWND_FULL: 999 case SCTP_XMIT_NAGLE_DELAY: 1000 /* We could not append this chunk, so put 1001 * the chunk back on the output queue. 1002 */ 1003 SCTP_DEBUG_PRINTK("sctp_outq_flush: could " 1004 "not transmit TSN: 0x%x, status: %d\n", 1005 ntohl(chunk->subh.data_hdr->tsn), 1006 status); 1007 sctp_outq_head_data(q, chunk); 1008 goto sctp_flush_out; 1009 break; 1010 1011 case SCTP_XMIT_OK: 1012 break; 1013 1014 default: 1015 BUG(); 1016 } 1017 1018 /* BUG: We assume that the sctp_packet_transmit() 1019 * call below will succeed all the time and add the 1020 * chunk to the transmitted list and restart the 1021 * timers. 1022 * It is possible that the call can fail under OOM 1023 * conditions. 1024 * 1025 * Is this really a problem? Won't this behave 1026 * like a lost TSN? 1027 */ 1028 list_add_tail(&chunk->transmitted_list, 1029 &transport->transmitted); 1030 1031 sctp_transport_reset_timers(transport, start_timer-1); 1032 1033 q->empty = 0; 1034 1035 /* Only let one DATA chunk get bundled with a 1036 * COOKIE-ECHO chunk. 1037 */ 1038 if (packet->has_cookie_echo) 1039 goto sctp_flush_out; 1040 } 1041 break; 1042 1043 default: 1044 /* Do nothing. */ 1045 break; 1046 } 1047 1048 sctp_flush_out: 1049 1050 /* Before returning, examine all the transports touched in 1051 * this call. Right now, we bluntly force clear all the 1052 * transports. Things might change after we implement Nagle. 1053 * But such an examination is still required. 1054 * 1055 * --xguo 1056 */ 1057 while ((ltransport = sctp_list_dequeue(&transport_list)) != NULL ) { 1058 struct sctp_transport *t = list_entry(ltransport, 1059 struct sctp_transport, 1060 send_ready); 1061 packet = &t->packet; 1062 if (!sctp_packet_empty(packet)) 1063 error = sctp_packet_transmit(packet); 1064 } 1065 1066 return error; 1067 } 1068 1069 /* Update unack_data based on the incoming SACK chunk */ 1070 static void sctp_sack_update_unack_data(struct sctp_association *assoc, 1071 struct sctp_sackhdr *sack) 1072 { 1073 sctp_sack_variable_t *frags; 1074 __u16 unack_data; 1075 int i; 1076 1077 unack_data = assoc->next_tsn - assoc->ctsn_ack_point - 1; 1078 1079 frags = sack->variable; 1080 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); i++) { 1081 unack_data -= ((ntohs(frags[i].gab.end) - 1082 ntohs(frags[i].gab.start) + 1)); 1083 } 1084 1085 assoc->unack_data = unack_data; 1086 } 1087 1088 /* Return the highest new tsn that is acknowledged by the given SACK chunk. */ 1089 static __u32 sctp_highest_new_tsn(struct sctp_sackhdr *sack, 1090 struct sctp_association *asoc) 1091 { 1092 struct sctp_transport *transport; 1093 struct sctp_chunk *chunk; 1094 __u32 highest_new_tsn, tsn; 1095 struct list_head *transport_list = &asoc->peer.transport_addr_list; 1096 1097 highest_new_tsn = ntohl(sack->cum_tsn_ack); 1098 1099 list_for_each_entry(transport, transport_list, transports) { 1100 list_for_each_entry(chunk, &transport->transmitted, 1101 transmitted_list) { 1102 tsn = ntohl(chunk->subh.data_hdr->tsn); 1103 1104 if (!chunk->tsn_gap_acked && 1105 TSN_lt(highest_new_tsn, tsn) && 1106 sctp_acked(sack, tsn)) 1107 highest_new_tsn = tsn; 1108 } 1109 } 1110 1111 return highest_new_tsn; 1112 } 1113 1114 /* This is where we REALLY process a SACK. 1115 * 1116 * Process the SACK against the outqueue. Mostly, this just frees 1117 * things off the transmitted queue. 1118 */ 1119 int sctp_outq_sack(struct sctp_outq *q, struct sctp_sackhdr *sack) 1120 { 1121 struct sctp_association *asoc = q->asoc; 1122 struct sctp_transport *transport; 1123 struct sctp_chunk *tchunk = NULL; 1124 struct list_head *lchunk, *transport_list, *temp; 1125 sctp_sack_variable_t *frags = sack->variable; 1126 __u32 sack_ctsn, ctsn, tsn; 1127 __u32 highest_tsn, highest_new_tsn; 1128 __u32 sack_a_rwnd; 1129 unsigned outstanding; 1130 struct sctp_transport *primary = asoc->peer.primary_path; 1131 int count_of_newacks = 0; 1132 int gap_ack_blocks; 1133 1134 /* Grab the association's destination address list. */ 1135 transport_list = &asoc->peer.transport_addr_list; 1136 1137 sack_ctsn = ntohl(sack->cum_tsn_ack); 1138 gap_ack_blocks = ntohs(sack->num_gap_ack_blocks); 1139 /* 1140 * SFR-CACC algorithm: 1141 * On receipt of a SACK the sender SHOULD execute the 1142 * following statements. 1143 * 1144 * 1) If the cumulative ack in the SACK passes next tsn_at_change 1145 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be 1146 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for 1147 * all destinations. 1148 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE 1149 * is set the receiver of the SACK MUST take the following actions: 1150 * 1151 * A) Initialize the cacc_saw_newack to 0 for all destination 1152 * addresses. 1153 * 1154 * Only bother if changeover_active is set. Otherwise, this is 1155 * totally suboptimal to do on every SACK. 1156 */ 1157 if (primary->cacc.changeover_active) { 1158 u8 clear_cycling = 0; 1159 1160 if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) { 1161 primary->cacc.changeover_active = 0; 1162 clear_cycling = 1; 1163 } 1164 1165 if (clear_cycling || gap_ack_blocks) { 1166 list_for_each_entry(transport, transport_list, 1167 transports) { 1168 if (clear_cycling) 1169 transport->cacc.cycling_changeover = 0; 1170 if (gap_ack_blocks) 1171 transport->cacc.cacc_saw_newack = 0; 1172 } 1173 } 1174 } 1175 1176 /* Get the highest TSN in the sack. */ 1177 highest_tsn = sack_ctsn; 1178 if (gap_ack_blocks) 1179 highest_tsn += ntohs(frags[gap_ack_blocks - 1].gab.end); 1180 1181 if (TSN_lt(asoc->highest_sacked, highest_tsn)) { 1182 highest_new_tsn = highest_tsn; 1183 asoc->highest_sacked = highest_tsn; 1184 } else { 1185 highest_new_tsn = sctp_highest_new_tsn(sack, asoc); 1186 } 1187 1188 1189 /* Run through the retransmit queue. Credit bytes received 1190 * and free those chunks that we can. 1191 */ 1192 sctp_check_transmitted(q, &q->retransmit, NULL, sack, highest_new_tsn); 1193 1194 /* Run through the transmitted queue. 1195 * Credit bytes received and free those chunks which we can. 1196 * 1197 * This is a MASSIVE candidate for optimization. 1198 */ 1199 list_for_each_entry(transport, transport_list, transports) { 1200 sctp_check_transmitted(q, &transport->transmitted, 1201 transport, sack, highest_new_tsn); 1202 /* 1203 * SFR-CACC algorithm: 1204 * C) Let count_of_newacks be the number of 1205 * destinations for which cacc_saw_newack is set. 1206 */ 1207 if (transport->cacc.cacc_saw_newack) 1208 count_of_newacks ++; 1209 } 1210 1211 if (gap_ack_blocks) { 1212 list_for_each_entry(transport, transport_list, transports) 1213 sctp_mark_missing(q, &transport->transmitted, transport, 1214 highest_new_tsn, count_of_newacks); 1215 } 1216 1217 /* Move the Cumulative TSN Ack Point if appropriate. */ 1218 if (TSN_lt(asoc->ctsn_ack_point, sack_ctsn)) 1219 asoc->ctsn_ack_point = sack_ctsn; 1220 1221 /* Update unack_data field in the assoc. */ 1222 sctp_sack_update_unack_data(asoc, sack); 1223 1224 ctsn = asoc->ctsn_ack_point; 1225 1226 /* Throw away stuff rotting on the sack queue. */ 1227 list_for_each_safe(lchunk, temp, &q->sacked) { 1228 tchunk = list_entry(lchunk, struct sctp_chunk, 1229 transmitted_list); 1230 tsn = ntohl(tchunk->subh.data_hdr->tsn); 1231 if (TSN_lte(tsn, ctsn)) { 1232 list_del_init(&tchunk->transmitted_list); 1233 sctp_chunk_free(tchunk); 1234 } 1235 } 1236 1237 /* ii) Set rwnd equal to the newly received a_rwnd minus the 1238 * number of bytes still outstanding after processing the 1239 * Cumulative TSN Ack and the Gap Ack Blocks. 1240 */ 1241 1242 sack_a_rwnd = ntohl(sack->a_rwnd); 1243 outstanding = q->outstanding_bytes; 1244 1245 if (outstanding < sack_a_rwnd) 1246 sack_a_rwnd -= outstanding; 1247 else 1248 sack_a_rwnd = 0; 1249 1250 asoc->peer.rwnd = sack_a_rwnd; 1251 1252 sctp_generate_fwdtsn(q, sack_ctsn); 1253 1254 SCTP_DEBUG_PRINTK("%s: sack Cumulative TSN Ack is 0x%x.\n", 1255 __func__, sack_ctsn); 1256 SCTP_DEBUG_PRINTK("%s: Cumulative TSN Ack of association, " 1257 "%p is 0x%x. Adv peer ack point: 0x%x\n", 1258 __func__, asoc, ctsn, asoc->adv_peer_ack_point); 1259 1260 /* See if all chunks are acked. 1261 * Make sure the empty queue handler will get run later. 1262 */ 1263 q->empty = (list_empty(&q->out_chunk_list) && 1264 list_empty(&q->retransmit)); 1265 if (!q->empty) 1266 goto finish; 1267 1268 list_for_each_entry(transport, transport_list, transports) { 1269 q->empty = q->empty && list_empty(&transport->transmitted); 1270 if (!q->empty) 1271 goto finish; 1272 } 1273 1274 SCTP_DEBUG_PRINTK("sack queue is empty.\n"); 1275 finish: 1276 return q->empty; 1277 } 1278 1279 /* Is the outqueue empty? */ 1280 int sctp_outq_is_empty(const struct sctp_outq *q) 1281 { 1282 return q->empty; 1283 } 1284 1285 /******************************************************************** 1286 * 2nd Level Abstractions 1287 ********************************************************************/ 1288 1289 /* Go through a transport's transmitted list or the association's retransmit 1290 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked. 1291 * The retransmit list will not have an associated transport. 1292 * 1293 * I added coherent debug information output. --xguo 1294 * 1295 * Instead of printing 'sacked' or 'kept' for each TSN on the 1296 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5. 1297 * KEPT TSN6-TSN7, etc. 1298 */ 1299 static void sctp_check_transmitted(struct sctp_outq *q, 1300 struct list_head *transmitted_queue, 1301 struct sctp_transport *transport, 1302 struct sctp_sackhdr *sack, 1303 __u32 highest_new_tsn_in_sack) 1304 { 1305 struct list_head *lchunk; 1306 struct sctp_chunk *tchunk; 1307 struct list_head tlist; 1308 __u32 tsn; 1309 __u32 sack_ctsn; 1310 __u32 rtt; 1311 __u8 restart_timer = 0; 1312 int bytes_acked = 0; 1313 1314 /* These state variables are for coherent debug output. --xguo */ 1315 1316 #if SCTP_DEBUG 1317 __u32 dbg_ack_tsn = 0; /* An ACKed TSN range starts here... */ 1318 __u32 dbg_last_ack_tsn = 0; /* ...and finishes here. */ 1319 __u32 dbg_kept_tsn = 0; /* An un-ACKed range starts here... */ 1320 __u32 dbg_last_kept_tsn = 0; /* ...and finishes here. */ 1321 1322 /* 0 : The last TSN was ACKed. 1323 * 1 : The last TSN was NOT ACKed (i.e. KEPT). 1324 * -1: We need to initialize. 1325 */ 1326 int dbg_prt_state = -1; 1327 #endif /* SCTP_DEBUG */ 1328 1329 sack_ctsn = ntohl(sack->cum_tsn_ack); 1330 1331 INIT_LIST_HEAD(&tlist); 1332 1333 /* The while loop will skip empty transmitted queues. */ 1334 while (NULL != (lchunk = sctp_list_dequeue(transmitted_queue))) { 1335 tchunk = list_entry(lchunk, struct sctp_chunk, 1336 transmitted_list); 1337 1338 if (sctp_chunk_abandoned(tchunk)) { 1339 /* Move the chunk to abandoned list. */ 1340 sctp_insert_list(&q->abandoned, lchunk); 1341 1342 /* If this chunk has not been acked, stop 1343 * considering it as 'outstanding'. 1344 */ 1345 if (!tchunk->tsn_gap_acked) { 1346 tchunk->transport->flight_size -= 1347 sctp_data_size(tchunk); 1348 q->outstanding_bytes -= sctp_data_size(tchunk); 1349 } 1350 continue; 1351 } 1352 1353 tsn = ntohl(tchunk->subh.data_hdr->tsn); 1354 if (sctp_acked(sack, tsn)) { 1355 /* If this queue is the retransmit queue, the 1356 * retransmit timer has already reclaimed 1357 * the outstanding bytes for this chunk, so only 1358 * count bytes associated with a transport. 1359 */ 1360 if (transport) { 1361 /* If this chunk is being used for RTT 1362 * measurement, calculate the RTT and update 1363 * the RTO using this value. 1364 * 1365 * 6.3.1 C5) Karn's algorithm: RTT measurements 1366 * MUST NOT be made using packets that were 1367 * retransmitted (and thus for which it is 1368 * ambiguous whether the reply was for the 1369 * first instance of the packet or a later 1370 * instance). 1371 */ 1372 if (!tchunk->tsn_gap_acked && 1373 !tchunk->resent && 1374 tchunk->rtt_in_progress) { 1375 tchunk->rtt_in_progress = 0; 1376 rtt = jiffies - tchunk->sent_at; 1377 sctp_transport_update_rto(transport, 1378 rtt); 1379 } 1380 } 1381 if (TSN_lte(tsn, sack_ctsn)) { 1382 /* RFC 2960 6.3.2 Retransmission Timer Rules 1383 * 1384 * R3) Whenever a SACK is received 1385 * that acknowledges the DATA chunk 1386 * with the earliest outstanding TSN 1387 * for that address, restart T3-rtx 1388 * timer for that address with its 1389 * current RTO. 1390 */ 1391 restart_timer = 1; 1392 1393 if (!tchunk->tsn_gap_acked) { 1394 tchunk->tsn_gap_acked = 1; 1395 bytes_acked += sctp_data_size(tchunk); 1396 /* 1397 * SFR-CACC algorithm: 1398 * 2) If the SACK contains gap acks 1399 * and the flag CHANGEOVER_ACTIVE is 1400 * set the receiver of the SACK MUST 1401 * take the following action: 1402 * 1403 * B) For each TSN t being acked that 1404 * has not been acked in any SACK so 1405 * far, set cacc_saw_newack to 1 for 1406 * the destination that the TSN was 1407 * sent to. 1408 */ 1409 if (transport && 1410 sack->num_gap_ack_blocks && 1411 q->asoc->peer.primary_path->cacc. 1412 changeover_active) 1413 transport->cacc.cacc_saw_newack 1414 = 1; 1415 } 1416 1417 list_add_tail(&tchunk->transmitted_list, 1418 &q->sacked); 1419 } else { 1420 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2 1421 * M2) Each time a SACK arrives reporting 1422 * 'Stray DATA chunk(s)' record the highest TSN 1423 * reported as newly acknowledged, call this 1424 * value 'HighestTSNinSack'. A newly 1425 * acknowledged DATA chunk is one not 1426 * previously acknowledged in a SACK. 1427 * 1428 * When the SCTP sender of data receives a SACK 1429 * chunk that acknowledges, for the first time, 1430 * the receipt of a DATA chunk, all the still 1431 * unacknowledged DATA chunks whose TSN is 1432 * older than that newly acknowledged DATA 1433 * chunk, are qualified as 'Stray DATA chunks'. 1434 */ 1435 if (!tchunk->tsn_gap_acked) { 1436 tchunk->tsn_gap_acked = 1; 1437 bytes_acked += sctp_data_size(tchunk); 1438 } 1439 list_add_tail(lchunk, &tlist); 1440 } 1441 1442 #if SCTP_DEBUG 1443 switch (dbg_prt_state) { 1444 case 0: /* last TSN was ACKed */ 1445 if (dbg_last_ack_tsn + 1 == tsn) { 1446 /* This TSN belongs to the 1447 * current ACK range. 1448 */ 1449 break; 1450 } 1451 1452 if (dbg_last_ack_tsn != dbg_ack_tsn) { 1453 /* Display the end of the 1454 * current range. 1455 */ 1456 SCTP_DEBUG_PRINTK("-%08x", 1457 dbg_last_ack_tsn); 1458 } 1459 1460 /* Start a new range. */ 1461 SCTP_DEBUG_PRINTK(",%08x", tsn); 1462 dbg_ack_tsn = tsn; 1463 break; 1464 1465 case 1: /* The last TSN was NOT ACKed. */ 1466 if (dbg_last_kept_tsn != dbg_kept_tsn) { 1467 /* Display the end of current range. */ 1468 SCTP_DEBUG_PRINTK("-%08x", 1469 dbg_last_kept_tsn); 1470 } 1471 1472 SCTP_DEBUG_PRINTK("\n"); 1473 1474 /* FALL THROUGH... */ 1475 default: 1476 /* This is the first-ever TSN we examined. */ 1477 /* Start a new range of ACK-ed TSNs. */ 1478 SCTP_DEBUG_PRINTK("ACKed: %08x", tsn); 1479 dbg_prt_state = 0; 1480 dbg_ack_tsn = tsn; 1481 } 1482 1483 dbg_last_ack_tsn = tsn; 1484 #endif /* SCTP_DEBUG */ 1485 1486 } else { 1487 if (tchunk->tsn_gap_acked) { 1488 SCTP_DEBUG_PRINTK("%s: Receiver reneged on " 1489 "data TSN: 0x%x\n", 1490 __func__, 1491 tsn); 1492 tchunk->tsn_gap_acked = 0; 1493 1494 bytes_acked -= sctp_data_size(tchunk); 1495 1496 /* RFC 2960 6.3.2 Retransmission Timer Rules 1497 * 1498 * R4) Whenever a SACK is received missing a 1499 * TSN that was previously acknowledged via a 1500 * Gap Ack Block, start T3-rtx for the 1501 * destination address to which the DATA 1502 * chunk was originally 1503 * transmitted if it is not already running. 1504 */ 1505 restart_timer = 1; 1506 } 1507 1508 list_add_tail(lchunk, &tlist); 1509 1510 #if SCTP_DEBUG 1511 /* See the above comments on ACK-ed TSNs. */ 1512 switch (dbg_prt_state) { 1513 case 1: 1514 if (dbg_last_kept_tsn + 1 == tsn) 1515 break; 1516 1517 if (dbg_last_kept_tsn != dbg_kept_tsn) 1518 SCTP_DEBUG_PRINTK("-%08x", 1519 dbg_last_kept_tsn); 1520 1521 SCTP_DEBUG_PRINTK(",%08x", tsn); 1522 dbg_kept_tsn = tsn; 1523 break; 1524 1525 case 0: 1526 if (dbg_last_ack_tsn != dbg_ack_tsn) 1527 SCTP_DEBUG_PRINTK("-%08x", 1528 dbg_last_ack_tsn); 1529 SCTP_DEBUG_PRINTK("\n"); 1530 1531 /* FALL THROUGH... */ 1532 default: 1533 SCTP_DEBUG_PRINTK("KEPT: %08x",tsn); 1534 dbg_prt_state = 1; 1535 dbg_kept_tsn = tsn; 1536 } 1537 1538 dbg_last_kept_tsn = tsn; 1539 #endif /* SCTP_DEBUG */ 1540 } 1541 } 1542 1543 #if SCTP_DEBUG 1544 /* Finish off the last range, displaying its ending TSN. */ 1545 switch (dbg_prt_state) { 1546 case 0: 1547 if (dbg_last_ack_tsn != dbg_ack_tsn) { 1548 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_ack_tsn); 1549 } else { 1550 SCTP_DEBUG_PRINTK("\n"); 1551 } 1552 break; 1553 1554 case 1: 1555 if (dbg_last_kept_tsn != dbg_kept_tsn) { 1556 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_kept_tsn); 1557 } else { 1558 SCTP_DEBUG_PRINTK("\n"); 1559 } 1560 } 1561 #endif /* SCTP_DEBUG */ 1562 if (transport) { 1563 if (bytes_acked) { 1564 /* 8.2. When an outstanding TSN is acknowledged, 1565 * the endpoint shall clear the error counter of 1566 * the destination transport address to which the 1567 * DATA chunk was last sent. 1568 * The association's overall error counter is 1569 * also cleared. 1570 */ 1571 transport->error_count = 0; 1572 transport->asoc->overall_error_count = 0; 1573 1574 /* Mark the destination transport address as 1575 * active if it is not so marked. 1576 */ 1577 if ((transport->state == SCTP_INACTIVE) || 1578 (transport->state == SCTP_UNCONFIRMED)) { 1579 sctp_assoc_control_transport( 1580 transport->asoc, 1581 transport, 1582 SCTP_TRANSPORT_UP, 1583 SCTP_RECEIVED_SACK); 1584 } 1585 1586 sctp_transport_raise_cwnd(transport, sack_ctsn, 1587 bytes_acked); 1588 1589 transport->flight_size -= bytes_acked; 1590 if (transport->flight_size == 0) 1591 transport->partial_bytes_acked = 0; 1592 q->outstanding_bytes -= bytes_acked; 1593 } else { 1594 /* RFC 2960 6.1, sctpimpguide-06 2.15.2 1595 * When a sender is doing zero window probing, it 1596 * should not timeout the association if it continues 1597 * to receive new packets from the receiver. The 1598 * reason is that the receiver MAY keep its window 1599 * closed for an indefinite time. 1600 * A sender is doing zero window probing when the 1601 * receiver's advertised window is zero, and there is 1602 * only one data chunk in flight to the receiver. 1603 */ 1604 if (!q->asoc->peer.rwnd && 1605 !list_empty(&tlist) && 1606 (sack_ctsn+2 == q->asoc->next_tsn)) { 1607 SCTP_DEBUG_PRINTK("%s: SACK received for zero " 1608 "window probe: %u\n", 1609 __func__, sack_ctsn); 1610 q->asoc->overall_error_count = 0; 1611 transport->error_count = 0; 1612 } 1613 } 1614 1615 /* RFC 2960 6.3.2 Retransmission Timer Rules 1616 * 1617 * R2) Whenever all outstanding data sent to an address have 1618 * been acknowledged, turn off the T3-rtx timer of that 1619 * address. 1620 */ 1621 if (!transport->flight_size) { 1622 if (timer_pending(&transport->T3_rtx_timer) && 1623 del_timer(&transport->T3_rtx_timer)) { 1624 sctp_transport_put(transport); 1625 } 1626 } else if (restart_timer) { 1627 if (!mod_timer(&transport->T3_rtx_timer, 1628 jiffies + transport->rto)) 1629 sctp_transport_hold(transport); 1630 } 1631 } 1632 1633 list_splice(&tlist, transmitted_queue); 1634 } 1635 1636 /* Mark chunks as missing and consequently may get retransmitted. */ 1637 static void sctp_mark_missing(struct sctp_outq *q, 1638 struct list_head *transmitted_queue, 1639 struct sctp_transport *transport, 1640 __u32 highest_new_tsn_in_sack, 1641 int count_of_newacks) 1642 { 1643 struct sctp_chunk *chunk; 1644 __u32 tsn; 1645 char do_fast_retransmit = 0; 1646 struct sctp_transport *primary = q->asoc->peer.primary_path; 1647 1648 list_for_each_entry(chunk, transmitted_queue, transmitted_list) { 1649 1650 tsn = ntohl(chunk->subh.data_hdr->tsn); 1651 1652 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all 1653 * 'Unacknowledged TSN's', if the TSN number of an 1654 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack' 1655 * value, increment the 'TSN.Missing.Report' count on that 1656 * chunk if it has NOT been fast retransmitted or marked for 1657 * fast retransmit already. 1658 */ 1659 if (chunk->fast_retransmit == SCTP_CAN_FRTX && 1660 !chunk->tsn_gap_acked && 1661 TSN_lt(tsn, highest_new_tsn_in_sack)) { 1662 1663 /* SFR-CACC may require us to skip marking 1664 * this chunk as missing. 1665 */ 1666 if (!transport || !sctp_cacc_skip(primary, transport, 1667 count_of_newacks, tsn)) { 1668 chunk->tsn_missing_report++; 1669 1670 SCTP_DEBUG_PRINTK( 1671 "%s: TSN 0x%x missing counter: %d\n", 1672 __func__, tsn, 1673 chunk->tsn_missing_report); 1674 } 1675 } 1676 /* 1677 * M4) If any DATA chunk is found to have a 1678 * 'TSN.Missing.Report' 1679 * value larger than or equal to 3, mark that chunk for 1680 * retransmission and start the fast retransmit procedure. 1681 */ 1682 1683 if (chunk->tsn_missing_report >= 3) { 1684 chunk->fast_retransmit = SCTP_NEED_FRTX; 1685 do_fast_retransmit = 1; 1686 } 1687 } 1688 1689 if (transport) { 1690 if (do_fast_retransmit) 1691 sctp_retransmit(q, transport, SCTP_RTXR_FAST_RTX); 1692 1693 SCTP_DEBUG_PRINTK("%s: transport: %p, cwnd: %d, " 1694 "ssthresh: %d, flight_size: %d, pba: %d\n", 1695 __func__, transport, transport->cwnd, 1696 transport->ssthresh, transport->flight_size, 1697 transport->partial_bytes_acked); 1698 } 1699 } 1700 1701 /* Is the given TSN acked by this packet? */ 1702 static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn) 1703 { 1704 int i; 1705 sctp_sack_variable_t *frags; 1706 __u16 gap; 1707 __u32 ctsn = ntohl(sack->cum_tsn_ack); 1708 1709 if (TSN_lte(tsn, ctsn)) 1710 goto pass; 1711 1712 /* 3.3.4 Selective Acknowledgement (SACK) (3): 1713 * 1714 * Gap Ack Blocks: 1715 * These fields contain the Gap Ack Blocks. They are repeated 1716 * for each Gap Ack Block up to the number of Gap Ack Blocks 1717 * defined in the Number of Gap Ack Blocks field. All DATA 1718 * chunks with TSNs greater than or equal to (Cumulative TSN 1719 * Ack + Gap Ack Block Start) and less than or equal to 1720 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack 1721 * Block are assumed to have been received correctly. 1722 */ 1723 1724 frags = sack->variable; 1725 gap = tsn - ctsn; 1726 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); ++i) { 1727 if (TSN_lte(ntohs(frags[i].gab.start), gap) && 1728 TSN_lte(gap, ntohs(frags[i].gab.end))) 1729 goto pass; 1730 } 1731 1732 return 0; 1733 pass: 1734 return 1; 1735 } 1736 1737 static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip *skiplist, 1738 int nskips, __be16 stream) 1739 { 1740 int i; 1741 1742 for (i = 0; i < nskips; i++) { 1743 if (skiplist[i].stream == stream) 1744 return i; 1745 } 1746 return i; 1747 } 1748 1749 /* Create and add a fwdtsn chunk to the outq's control queue if needed. */ 1750 static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 ctsn) 1751 { 1752 struct sctp_association *asoc = q->asoc; 1753 struct sctp_chunk *ftsn_chunk = NULL; 1754 struct sctp_fwdtsn_skip ftsn_skip_arr[10]; 1755 int nskips = 0; 1756 int skip_pos = 0; 1757 __u32 tsn; 1758 struct sctp_chunk *chunk; 1759 struct list_head *lchunk, *temp; 1760 1761 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the 1762 * received SACK. 1763 * 1764 * If (Advanced.Peer.Ack.Point < SackCumAck), then update 1765 * Advanced.Peer.Ack.Point to be equal to SackCumAck. 1766 */ 1767 if (TSN_lt(asoc->adv_peer_ack_point, ctsn)) 1768 asoc->adv_peer_ack_point = ctsn; 1769 1770 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point" 1771 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as 1772 * the chunk next in the out-queue space is marked as "abandoned" as 1773 * shown in the following example: 1774 * 1775 * Assuming that a SACK arrived with the Cumulative TSN ACK 102 1776 * and the Advanced.Peer.Ack.Point is updated to this value: 1777 * 1778 * out-queue at the end of ==> out-queue after Adv.Ack.Point 1779 * normal SACK processing local advancement 1780 * ... ... 1781 * Adv.Ack.Pt-> 102 acked 102 acked 1782 * 103 abandoned 103 abandoned 1783 * 104 abandoned Adv.Ack.P-> 104 abandoned 1784 * 105 105 1785 * 106 acked 106 acked 1786 * ... ... 1787 * 1788 * In this example, the data sender successfully advanced the 1789 * "Advanced.Peer.Ack.Point" from 102 to 104 locally. 1790 */ 1791 list_for_each_safe(lchunk, temp, &q->abandoned) { 1792 chunk = list_entry(lchunk, struct sctp_chunk, 1793 transmitted_list); 1794 tsn = ntohl(chunk->subh.data_hdr->tsn); 1795 1796 /* Remove any chunks in the abandoned queue that are acked by 1797 * the ctsn. 1798 */ 1799 if (TSN_lte(tsn, ctsn)) { 1800 list_del_init(lchunk); 1801 sctp_chunk_free(chunk); 1802 } else { 1803 if (TSN_lte(tsn, asoc->adv_peer_ack_point+1)) { 1804 asoc->adv_peer_ack_point = tsn; 1805 if (chunk->chunk_hdr->flags & 1806 SCTP_DATA_UNORDERED) 1807 continue; 1808 skip_pos = sctp_get_skip_pos(&ftsn_skip_arr[0], 1809 nskips, 1810 chunk->subh.data_hdr->stream); 1811 ftsn_skip_arr[skip_pos].stream = 1812 chunk->subh.data_hdr->stream; 1813 ftsn_skip_arr[skip_pos].ssn = 1814 chunk->subh.data_hdr->ssn; 1815 if (skip_pos == nskips) 1816 nskips++; 1817 if (nskips == 10) 1818 break; 1819 } else 1820 break; 1821 } 1822 } 1823 1824 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point" 1825 * is greater than the Cumulative TSN ACK carried in the received 1826 * SACK, the data sender MUST send the data receiver a FORWARD TSN 1827 * chunk containing the latest value of the 1828 * "Advanced.Peer.Ack.Point". 1829 * 1830 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD 1831 * list each stream and sequence number in the forwarded TSN. This 1832 * information will enable the receiver to easily find any 1833 * stranded TSN's waiting on stream reorder queues. Each stream 1834 * SHOULD only be reported once; this means that if multiple 1835 * abandoned messages occur in the same stream then only the 1836 * highest abandoned stream sequence number is reported. If the 1837 * total size of the FORWARD TSN does NOT fit in a single MTU then 1838 * the sender of the FORWARD TSN SHOULD lower the 1839 * Advanced.Peer.Ack.Point to the last TSN that will fit in a 1840 * single MTU. 1841 */ 1842 if (asoc->adv_peer_ack_point > ctsn) 1843 ftsn_chunk = sctp_make_fwdtsn(asoc, asoc->adv_peer_ack_point, 1844 nskips, &ftsn_skip_arr[0]); 1845 1846 if (ftsn_chunk) { 1847 list_add_tail(&ftsn_chunk->list, &q->control_chunk_list); 1848 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 1849 } 1850 } 1851