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 if (chunk->transport) 410 chunk->transport->flight_size -= 411 sctp_data_size(chunk); 412 q->outstanding_bytes -= sctp_data_size(chunk); 413 q->asoc->peer.rwnd += (sctp_data_size(chunk) + 414 sizeof(struct sk_buff)); 415 } 416 continue; 417 } 418 419 /* If we are doing retransmission due to a timeout or pmtu 420 * discovery, only the chunks that are not yet acked should 421 * be added to the retransmit queue. 422 */ 423 if ((reason == SCTP_RTXR_FAST_RTX && 424 (chunk->fast_retransmit == SCTP_NEED_FRTX)) || 425 (reason != SCTP_RTXR_FAST_RTX && !chunk->tsn_gap_acked)) { 426 /* If this chunk was sent less then 1 rto ago, do not 427 * retransmit this chunk, but give the peer time 428 * to acknowlege it. Do this only when 429 * retransmitting due to T3 timeout. 430 */ 431 if (reason == SCTP_RTXR_T3_RTX && 432 time_before(jiffies, chunk->sent_at + 433 transport->last_rto)) 434 continue; 435 436 /* RFC 2960 6.2.1 Processing a Received SACK 437 * 438 * C) Any time a DATA chunk is marked for 439 * retransmission (via either T3-rtx timer expiration 440 * (Section 6.3.3) or via fast retransmit 441 * (Section 7.2.4)), add the data size of those 442 * chunks to the rwnd. 443 */ 444 q->asoc->peer.rwnd += (sctp_data_size(chunk) + 445 sizeof(struct sk_buff)); 446 q->outstanding_bytes -= sctp_data_size(chunk); 447 if (chunk->transport) 448 transport->flight_size -= sctp_data_size(chunk); 449 450 /* sctpimpguide-05 Section 2.8.2 451 * M5) If a T3-rtx timer expires, the 452 * 'TSN.Missing.Report' of all affected TSNs is set 453 * to 0. 454 */ 455 chunk->tsn_missing_report = 0; 456 457 /* If a chunk that is being used for RTT measurement 458 * has to be retransmitted, we cannot use this chunk 459 * anymore for RTT measurements. Reset rto_pending so 460 * that a new RTT measurement is started when a new 461 * data chunk is sent. 462 */ 463 if (chunk->rtt_in_progress) { 464 chunk->rtt_in_progress = 0; 465 transport->rto_pending = 0; 466 } 467 468 /* Move the chunk to the retransmit queue. The chunks 469 * on the retransmit queue are always kept in order. 470 */ 471 list_del_init(lchunk); 472 sctp_insert_list(&q->retransmit, lchunk); 473 } 474 } 475 476 SCTP_DEBUG_PRINTK("%s: transport: %p, reason: %d, " 477 "cwnd: %d, ssthresh: %d, flight_size: %d, " 478 "pba: %d\n", __func__, 479 transport, reason, 480 transport->cwnd, transport->ssthresh, 481 transport->flight_size, 482 transport->partial_bytes_acked); 483 484 } 485 486 /* Mark all the eligible packets on a transport for retransmission and force 487 * one packet out. 488 */ 489 void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport, 490 sctp_retransmit_reason_t reason) 491 { 492 int error = 0; 493 494 switch(reason) { 495 case SCTP_RTXR_T3_RTX: 496 SCTP_INC_STATS(SCTP_MIB_T3_RETRANSMITS); 497 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_T3_RTX); 498 /* Update the retran path if the T3-rtx timer has expired for 499 * the current retran path. 500 */ 501 if (transport == transport->asoc->peer.retran_path) 502 sctp_assoc_update_retran_path(transport->asoc); 503 transport->asoc->rtx_data_chunks += 504 transport->asoc->unack_data; 505 break; 506 case SCTP_RTXR_FAST_RTX: 507 SCTP_INC_STATS(SCTP_MIB_FAST_RETRANSMITS); 508 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_FAST_RTX); 509 q->fast_rtx = 1; 510 break; 511 case SCTP_RTXR_PMTUD: 512 SCTP_INC_STATS(SCTP_MIB_PMTUD_RETRANSMITS); 513 break; 514 case SCTP_RTXR_T1_RTX: 515 SCTP_INC_STATS(SCTP_MIB_T1_RETRANSMITS); 516 transport->asoc->init_retries++; 517 break; 518 default: 519 BUG(); 520 } 521 522 sctp_retransmit_mark(q, transport, reason); 523 524 /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination, 525 * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by 526 * following the procedures outlined in C1 - C5. 527 */ 528 if (reason == SCTP_RTXR_T3_RTX) 529 sctp_generate_fwdtsn(q, q->asoc->ctsn_ack_point); 530 531 /* Flush the queues only on timeout, since fast_rtx is only 532 * triggered during sack processing and the queue 533 * will be flushed at the end. 534 */ 535 if (reason != SCTP_RTXR_FAST_RTX) 536 error = sctp_outq_flush(q, /* rtx_timeout */ 1); 537 538 if (error) 539 q->asoc->base.sk->sk_err = -error; 540 } 541 542 /* 543 * Transmit DATA chunks on the retransmit queue. Upon return from 544 * sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which 545 * need to be transmitted by the caller. 546 * We assume that pkt->transport has already been set. 547 * 548 * The return value is a normal kernel error return value. 549 */ 550 static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt, 551 int rtx_timeout, int *start_timer) 552 { 553 struct list_head *lqueue; 554 struct sctp_transport *transport = pkt->transport; 555 sctp_xmit_t status; 556 struct sctp_chunk *chunk, *chunk1; 557 struct sctp_association *asoc; 558 int fast_rtx; 559 int error = 0; 560 int timer = 0; 561 int done = 0; 562 563 asoc = q->asoc; 564 lqueue = &q->retransmit; 565 fast_rtx = q->fast_rtx; 566 567 /* This loop handles time-out retransmissions, fast retransmissions, 568 * and retransmissions due to opening of whindow. 569 * 570 * RFC 2960 6.3.3 Handle T3-rtx Expiration 571 * 572 * E3) Determine how many of the earliest (i.e., lowest TSN) 573 * outstanding DATA chunks for the address for which the 574 * T3-rtx has expired will fit into a single packet, subject 575 * to the MTU constraint for the path corresponding to the 576 * destination transport address to which the retransmission 577 * is being sent (this may be different from the address for 578 * which the timer expires [see Section 6.4]). Call this value 579 * K. Bundle and retransmit those K DATA chunks in a single 580 * packet to the destination endpoint. 581 * 582 * [Just to be painfully clear, if we are retransmitting 583 * because a timeout just happened, we should send only ONE 584 * packet of retransmitted data.] 585 * 586 * For fast retransmissions we also send only ONE packet. However, 587 * if we are just flushing the queue due to open window, we'll 588 * try to send as much as possible. 589 */ 590 list_for_each_entry_safe(chunk, chunk1, lqueue, transmitted_list) { 591 592 /* Make sure that Gap Acked TSNs are not retransmitted. A 593 * simple approach is just to move such TSNs out of the 594 * way and into a 'transmitted' queue and skip to the 595 * next chunk. 596 */ 597 if (chunk->tsn_gap_acked) { 598 list_del(&chunk->transmitted_list); 599 list_add_tail(&chunk->transmitted_list, 600 &transport->transmitted); 601 continue; 602 } 603 604 /* If we are doing fast retransmit, ignore non-fast_rtransmit 605 * chunks 606 */ 607 if (fast_rtx && !chunk->fast_retransmit) 608 continue; 609 610 /* Attempt to append this chunk to the packet. */ 611 status = sctp_packet_append_chunk(pkt, chunk); 612 613 switch (status) { 614 case SCTP_XMIT_PMTU_FULL: 615 /* Send this packet. */ 616 error = sctp_packet_transmit(pkt); 617 618 /* If we are retransmitting, we should only 619 * send a single packet. 620 */ 621 if (rtx_timeout || fast_rtx) 622 done = 1; 623 624 /* Bundle next chunk in the next round. */ 625 break; 626 627 case SCTP_XMIT_RWND_FULL: 628 /* Send this packet. */ 629 error = sctp_packet_transmit(pkt); 630 631 /* Stop sending DATA as there is no more room 632 * at the receiver. 633 */ 634 done = 1; 635 break; 636 637 case SCTP_XMIT_NAGLE_DELAY: 638 /* Send this packet. */ 639 error = sctp_packet_transmit(pkt); 640 641 /* Stop sending DATA because of nagle delay. */ 642 done = 1; 643 break; 644 645 default: 646 /* The append was successful, so add this chunk to 647 * the transmitted list. 648 */ 649 list_del(&chunk->transmitted_list); 650 list_add_tail(&chunk->transmitted_list, 651 &transport->transmitted); 652 653 /* Mark the chunk as ineligible for fast retransmit 654 * after it is retransmitted. 655 */ 656 if (chunk->fast_retransmit == SCTP_NEED_FRTX) 657 chunk->fast_retransmit = SCTP_DONT_FRTX; 658 659 /* Force start T3-rtx timer when fast retransmitting 660 * the earliest outstanding TSN 661 */ 662 if (!timer && fast_rtx && 663 ntohl(chunk->subh.data_hdr->tsn) == 664 asoc->ctsn_ack_point + 1) 665 timer = 2; 666 667 q->empty = 0; 668 break; 669 } 670 671 /* Set the timer if there were no errors */ 672 if (!error && !timer) 673 timer = 1; 674 675 if (done) 676 break; 677 } 678 679 /* If we are here due to a retransmit timeout or a fast 680 * retransmit and if there are any chunks left in the retransmit 681 * queue that could not fit in the PMTU sized packet, they need 682 * to be marked as ineligible for a subsequent fast retransmit. 683 */ 684 if (rtx_timeout || fast_rtx) { 685 list_for_each_entry(chunk1, lqueue, transmitted_list) { 686 if (chunk1->fast_retransmit == SCTP_NEED_FRTX) 687 chunk1->fast_retransmit = SCTP_DONT_FRTX; 688 } 689 } 690 691 *start_timer = timer; 692 693 /* Clear fast retransmit hint */ 694 if (fast_rtx) 695 q->fast_rtx = 0; 696 697 return error; 698 } 699 700 /* Cork the outqueue so queued chunks are really queued. */ 701 int sctp_outq_uncork(struct sctp_outq *q) 702 { 703 int error = 0; 704 if (q->cork) 705 q->cork = 0; 706 error = sctp_outq_flush(q, 0); 707 return error; 708 } 709 710 711 /* 712 * Try to flush an outqueue. 713 * 714 * Description: Send everything in q which we legally can, subject to 715 * congestion limitations. 716 * * Note: This function can be called from multiple contexts so appropriate 717 * locking concerns must be made. Today we use the sock lock to protect 718 * this function. 719 */ 720 static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout) 721 { 722 struct sctp_packet *packet; 723 struct sctp_packet singleton; 724 struct sctp_association *asoc = q->asoc; 725 __u16 sport = asoc->base.bind_addr.port; 726 __u16 dport = asoc->peer.port; 727 __u32 vtag = asoc->peer.i.init_tag; 728 struct sctp_transport *transport = NULL; 729 struct sctp_transport *new_transport; 730 struct sctp_chunk *chunk, *tmp; 731 sctp_xmit_t status; 732 int error = 0; 733 int start_timer = 0; 734 int one_packet = 0; 735 736 /* These transports have chunks to send. */ 737 struct list_head transport_list; 738 struct list_head *ltransport; 739 740 INIT_LIST_HEAD(&transport_list); 741 packet = NULL; 742 743 /* 744 * 6.10 Bundling 745 * ... 746 * When bundling control chunks with DATA chunks, an 747 * endpoint MUST place control chunks first in the outbound 748 * SCTP packet. The transmitter MUST transmit DATA chunks 749 * within a SCTP packet in increasing order of TSN. 750 * ... 751 */ 752 753 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) { 754 list_del_init(&chunk->list); 755 756 /* Pick the right transport to use. */ 757 new_transport = chunk->transport; 758 759 if (!new_transport) { 760 /* 761 * If we have a prior transport pointer, see if 762 * the destination address of the chunk 763 * matches the destination address of the 764 * current transport. If not a match, then 765 * try to look up the transport with a given 766 * destination address. We do this because 767 * after processing ASCONFs, we may have new 768 * transports created. 769 */ 770 if (transport && 771 sctp_cmp_addr_exact(&chunk->dest, 772 &transport->ipaddr)) 773 new_transport = transport; 774 else 775 new_transport = sctp_assoc_lookup_paddr(asoc, 776 &chunk->dest); 777 778 /* if we still don't have a new transport, then 779 * use the current active path. 780 */ 781 if (!new_transport) 782 new_transport = asoc->peer.active_path; 783 } else if ((new_transport->state == SCTP_INACTIVE) || 784 (new_transport->state == SCTP_UNCONFIRMED)) { 785 /* If the chunk is Heartbeat or Heartbeat Ack, 786 * send it to chunk->transport, even if it's 787 * inactive. 788 * 789 * 3.3.6 Heartbeat Acknowledgement: 790 * ... 791 * A HEARTBEAT ACK is always sent to the source IP 792 * address of the IP datagram containing the 793 * HEARTBEAT chunk to which this ack is responding. 794 * ... 795 * 796 * ASCONF_ACKs also must be sent to the source. 797 */ 798 if (chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT && 799 chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT_ACK && 800 chunk->chunk_hdr->type != SCTP_CID_ASCONF_ACK) 801 new_transport = asoc->peer.active_path; 802 } 803 804 /* Are we switching transports? 805 * Take care of transport locks. 806 */ 807 if (new_transport != transport) { 808 transport = new_transport; 809 if (list_empty(&transport->send_ready)) { 810 list_add_tail(&transport->send_ready, 811 &transport_list); 812 } 813 packet = &transport->packet; 814 sctp_packet_config(packet, vtag, 815 asoc->peer.ecn_capable); 816 } 817 818 switch (chunk->chunk_hdr->type) { 819 /* 820 * 6.10 Bundling 821 * ... 822 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN 823 * COMPLETE with any other chunks. [Send them immediately.] 824 */ 825 case SCTP_CID_INIT: 826 case SCTP_CID_INIT_ACK: 827 case SCTP_CID_SHUTDOWN_COMPLETE: 828 sctp_packet_init(&singleton, transport, sport, dport); 829 sctp_packet_config(&singleton, vtag, 0); 830 sctp_packet_append_chunk(&singleton, chunk); 831 error = sctp_packet_transmit(&singleton); 832 if (error < 0) 833 return error; 834 break; 835 836 case SCTP_CID_ABORT: 837 if (sctp_test_T_bit(chunk)) { 838 packet->vtag = asoc->c.my_vtag; 839 } 840 /* The following chunks are "response" chunks, i.e. 841 * they are generated in response to something we 842 * received. If we are sending these, then we can 843 * send only 1 packet containing these chunks. 844 */ 845 case SCTP_CID_HEARTBEAT_ACK: 846 case SCTP_CID_SHUTDOWN_ACK: 847 case SCTP_CID_COOKIE_ACK: 848 case SCTP_CID_COOKIE_ECHO: 849 case SCTP_CID_ERROR: 850 case SCTP_CID_ECN_CWR: 851 case SCTP_CID_ASCONF_ACK: 852 one_packet = 1; 853 /* Fall throught */ 854 855 case SCTP_CID_SACK: 856 case SCTP_CID_HEARTBEAT: 857 case SCTP_CID_SHUTDOWN: 858 case SCTP_CID_ECN_ECNE: 859 case SCTP_CID_ASCONF: 860 case SCTP_CID_FWD_TSN: 861 status = sctp_packet_transmit_chunk(packet, chunk, 862 one_packet); 863 if (status != SCTP_XMIT_OK) { 864 /* put the chunk back */ 865 list_add(&chunk->list, &q->control_chunk_list); 866 } 867 break; 868 869 default: 870 /* We built a chunk with an illegal type! */ 871 BUG(); 872 } 873 } 874 875 /* Is it OK to send data chunks? */ 876 switch (asoc->state) { 877 case SCTP_STATE_COOKIE_ECHOED: 878 /* Only allow bundling when this packet has a COOKIE-ECHO 879 * chunk. 880 */ 881 if (!packet || !packet->has_cookie_echo) 882 break; 883 884 /* fallthru */ 885 case SCTP_STATE_ESTABLISHED: 886 case SCTP_STATE_SHUTDOWN_PENDING: 887 case SCTP_STATE_SHUTDOWN_RECEIVED: 888 /* 889 * RFC 2960 6.1 Transmission of DATA Chunks 890 * 891 * C) When the time comes for the sender to transmit, 892 * before sending new DATA chunks, the sender MUST 893 * first transmit any outstanding DATA chunks which 894 * are marked for retransmission (limited by the 895 * current cwnd). 896 */ 897 if (!list_empty(&q->retransmit)) { 898 if (transport == asoc->peer.retran_path) 899 goto retran; 900 901 /* Switch transports & prepare the packet. */ 902 903 transport = asoc->peer.retran_path; 904 905 if (list_empty(&transport->send_ready)) { 906 list_add_tail(&transport->send_ready, 907 &transport_list); 908 } 909 910 packet = &transport->packet; 911 sctp_packet_config(packet, vtag, 912 asoc->peer.ecn_capable); 913 retran: 914 error = sctp_outq_flush_rtx(q, packet, 915 rtx_timeout, &start_timer); 916 917 if (start_timer) 918 sctp_transport_reset_timers(transport, 919 start_timer-1); 920 921 /* This can happen on COOKIE-ECHO resend. Only 922 * one chunk can get bundled with a COOKIE-ECHO. 923 */ 924 if (packet->has_cookie_echo) 925 goto sctp_flush_out; 926 927 /* Don't send new data if there is still data 928 * waiting to retransmit. 929 */ 930 if (!list_empty(&q->retransmit)) 931 goto sctp_flush_out; 932 } 933 934 /* Finally, transmit new packets. */ 935 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) { 936 /* RFC 2960 6.5 Every DATA chunk MUST carry a valid 937 * stream identifier. 938 */ 939 if (chunk->sinfo.sinfo_stream >= 940 asoc->c.sinit_num_ostreams) { 941 942 /* Mark as failed send. */ 943 sctp_chunk_fail(chunk, SCTP_ERROR_INV_STRM); 944 sctp_chunk_free(chunk); 945 continue; 946 } 947 948 /* Has this chunk expired? */ 949 if (sctp_chunk_abandoned(chunk)) { 950 sctp_chunk_fail(chunk, 0); 951 sctp_chunk_free(chunk); 952 continue; 953 } 954 955 /* If there is a specified transport, use it. 956 * Otherwise, we want to use the active path. 957 */ 958 new_transport = chunk->transport; 959 if (!new_transport || 960 ((new_transport->state == SCTP_INACTIVE) || 961 (new_transport->state == SCTP_UNCONFIRMED))) 962 new_transport = asoc->peer.active_path; 963 964 /* Change packets if necessary. */ 965 if (new_transport != transport) { 966 transport = new_transport; 967 968 /* Schedule to have this transport's 969 * packet flushed. 970 */ 971 if (list_empty(&transport->send_ready)) { 972 list_add_tail(&transport->send_ready, 973 &transport_list); 974 } 975 976 packet = &transport->packet; 977 sctp_packet_config(packet, vtag, 978 asoc->peer.ecn_capable); 979 } 980 981 SCTP_DEBUG_PRINTK("sctp_outq_flush(%p, %p[%s]), ", 982 q, chunk, 983 chunk && chunk->chunk_hdr ? 984 sctp_cname(SCTP_ST_CHUNK( 985 chunk->chunk_hdr->type)) 986 : "Illegal Chunk"); 987 988 SCTP_DEBUG_PRINTK("TX TSN 0x%x skb->head " 989 "%p skb->users %d.\n", 990 ntohl(chunk->subh.data_hdr->tsn), 991 chunk->skb ?chunk->skb->head : NULL, 992 chunk->skb ? 993 atomic_read(&chunk->skb->users) : -1); 994 995 /* Add the chunk to the packet. */ 996 status = sctp_packet_transmit_chunk(packet, chunk, 0); 997 998 switch (status) { 999 case SCTP_XMIT_PMTU_FULL: 1000 case SCTP_XMIT_RWND_FULL: 1001 case SCTP_XMIT_NAGLE_DELAY: 1002 /* We could not append this chunk, so put 1003 * the chunk back on the output queue. 1004 */ 1005 SCTP_DEBUG_PRINTK("sctp_outq_flush: could " 1006 "not transmit TSN: 0x%x, status: %d\n", 1007 ntohl(chunk->subh.data_hdr->tsn), 1008 status); 1009 sctp_outq_head_data(q, chunk); 1010 goto sctp_flush_out; 1011 break; 1012 1013 case SCTP_XMIT_OK: 1014 break; 1015 1016 default: 1017 BUG(); 1018 } 1019 1020 /* BUG: We assume that the sctp_packet_transmit() 1021 * call below will succeed all the time and add the 1022 * chunk to the transmitted list and restart the 1023 * timers. 1024 * It is possible that the call can fail under OOM 1025 * conditions. 1026 * 1027 * Is this really a problem? Won't this behave 1028 * like a lost TSN? 1029 */ 1030 list_add_tail(&chunk->transmitted_list, 1031 &transport->transmitted); 1032 1033 sctp_transport_reset_timers(transport, 0); 1034 1035 q->empty = 0; 1036 1037 /* Only let one DATA chunk get bundled with a 1038 * COOKIE-ECHO chunk. 1039 */ 1040 if (packet->has_cookie_echo) 1041 goto sctp_flush_out; 1042 } 1043 break; 1044 1045 default: 1046 /* Do nothing. */ 1047 break; 1048 } 1049 1050 sctp_flush_out: 1051 1052 /* Before returning, examine all the transports touched in 1053 * this call. Right now, we bluntly force clear all the 1054 * transports. Things might change after we implement Nagle. 1055 * But such an examination is still required. 1056 * 1057 * --xguo 1058 */ 1059 while ((ltransport = sctp_list_dequeue(&transport_list)) != NULL ) { 1060 struct sctp_transport *t = list_entry(ltransport, 1061 struct sctp_transport, 1062 send_ready); 1063 packet = &t->packet; 1064 if (!sctp_packet_empty(packet)) 1065 error = sctp_packet_transmit(packet); 1066 } 1067 1068 return error; 1069 } 1070 1071 /* Update unack_data based on the incoming SACK chunk */ 1072 static void sctp_sack_update_unack_data(struct sctp_association *assoc, 1073 struct sctp_sackhdr *sack) 1074 { 1075 sctp_sack_variable_t *frags; 1076 __u16 unack_data; 1077 int i; 1078 1079 unack_data = assoc->next_tsn - assoc->ctsn_ack_point - 1; 1080 1081 frags = sack->variable; 1082 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); i++) { 1083 unack_data -= ((ntohs(frags[i].gab.end) - 1084 ntohs(frags[i].gab.start) + 1)); 1085 } 1086 1087 assoc->unack_data = unack_data; 1088 } 1089 1090 /* Return the highest new tsn that is acknowledged by the given SACK chunk. */ 1091 static __u32 sctp_highest_new_tsn(struct sctp_sackhdr *sack, 1092 struct sctp_association *asoc) 1093 { 1094 struct sctp_transport *transport; 1095 struct sctp_chunk *chunk; 1096 __u32 highest_new_tsn, tsn; 1097 struct list_head *transport_list = &asoc->peer.transport_addr_list; 1098 1099 highest_new_tsn = ntohl(sack->cum_tsn_ack); 1100 1101 list_for_each_entry(transport, transport_list, transports) { 1102 list_for_each_entry(chunk, &transport->transmitted, 1103 transmitted_list) { 1104 tsn = ntohl(chunk->subh.data_hdr->tsn); 1105 1106 if (!chunk->tsn_gap_acked && 1107 TSN_lt(highest_new_tsn, tsn) && 1108 sctp_acked(sack, tsn)) 1109 highest_new_tsn = tsn; 1110 } 1111 } 1112 1113 return highest_new_tsn; 1114 } 1115 1116 /* This is where we REALLY process a SACK. 1117 * 1118 * Process the SACK against the outqueue. Mostly, this just frees 1119 * things off the transmitted queue. 1120 */ 1121 int sctp_outq_sack(struct sctp_outq *q, struct sctp_sackhdr *sack) 1122 { 1123 struct sctp_association *asoc = q->asoc; 1124 struct sctp_transport *transport; 1125 struct sctp_chunk *tchunk = NULL; 1126 struct list_head *lchunk, *transport_list, *temp; 1127 sctp_sack_variable_t *frags = sack->variable; 1128 __u32 sack_ctsn, ctsn, tsn; 1129 __u32 highest_tsn, highest_new_tsn; 1130 __u32 sack_a_rwnd; 1131 unsigned outstanding; 1132 struct sctp_transport *primary = asoc->peer.primary_path; 1133 int count_of_newacks = 0; 1134 int gap_ack_blocks; 1135 1136 /* Grab the association's destination address list. */ 1137 transport_list = &asoc->peer.transport_addr_list; 1138 1139 sack_ctsn = ntohl(sack->cum_tsn_ack); 1140 gap_ack_blocks = ntohs(sack->num_gap_ack_blocks); 1141 /* 1142 * SFR-CACC algorithm: 1143 * On receipt of a SACK the sender SHOULD execute the 1144 * following statements. 1145 * 1146 * 1) If the cumulative ack in the SACK passes next tsn_at_change 1147 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be 1148 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for 1149 * all destinations. 1150 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE 1151 * is set the receiver of the SACK MUST take the following actions: 1152 * 1153 * A) Initialize the cacc_saw_newack to 0 for all destination 1154 * addresses. 1155 * 1156 * Only bother if changeover_active is set. Otherwise, this is 1157 * totally suboptimal to do on every SACK. 1158 */ 1159 if (primary->cacc.changeover_active) { 1160 u8 clear_cycling = 0; 1161 1162 if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) { 1163 primary->cacc.changeover_active = 0; 1164 clear_cycling = 1; 1165 } 1166 1167 if (clear_cycling || gap_ack_blocks) { 1168 list_for_each_entry(transport, transport_list, 1169 transports) { 1170 if (clear_cycling) 1171 transport->cacc.cycling_changeover = 0; 1172 if (gap_ack_blocks) 1173 transport->cacc.cacc_saw_newack = 0; 1174 } 1175 } 1176 } 1177 1178 /* Get the highest TSN in the sack. */ 1179 highest_tsn = sack_ctsn; 1180 if (gap_ack_blocks) 1181 highest_tsn += ntohs(frags[gap_ack_blocks - 1].gab.end); 1182 1183 if (TSN_lt(asoc->highest_sacked, highest_tsn)) { 1184 highest_new_tsn = highest_tsn; 1185 asoc->highest_sacked = highest_tsn; 1186 } else { 1187 highest_new_tsn = sctp_highest_new_tsn(sack, asoc); 1188 } 1189 1190 1191 /* Run through the retransmit queue. Credit bytes received 1192 * and free those chunks that we can. 1193 */ 1194 sctp_check_transmitted(q, &q->retransmit, NULL, sack, highest_new_tsn); 1195 1196 /* Run through the transmitted queue. 1197 * Credit bytes received and free those chunks which we can. 1198 * 1199 * This is a MASSIVE candidate for optimization. 1200 */ 1201 list_for_each_entry(transport, transport_list, transports) { 1202 sctp_check_transmitted(q, &transport->transmitted, 1203 transport, sack, highest_new_tsn); 1204 /* 1205 * SFR-CACC algorithm: 1206 * C) Let count_of_newacks be the number of 1207 * destinations for which cacc_saw_newack is set. 1208 */ 1209 if (transport->cacc.cacc_saw_newack) 1210 count_of_newacks ++; 1211 } 1212 1213 if (gap_ack_blocks) { 1214 list_for_each_entry(transport, transport_list, transports) 1215 sctp_mark_missing(q, &transport->transmitted, transport, 1216 highest_new_tsn, count_of_newacks); 1217 } 1218 1219 /* Move the Cumulative TSN Ack Point if appropriate. */ 1220 if (TSN_lt(asoc->ctsn_ack_point, sack_ctsn)) 1221 asoc->ctsn_ack_point = sack_ctsn; 1222 1223 /* Update unack_data field in the assoc. */ 1224 sctp_sack_update_unack_data(asoc, sack); 1225 1226 ctsn = asoc->ctsn_ack_point; 1227 1228 /* Throw away stuff rotting on the sack queue. */ 1229 list_for_each_safe(lchunk, temp, &q->sacked) { 1230 tchunk = list_entry(lchunk, struct sctp_chunk, 1231 transmitted_list); 1232 tsn = ntohl(tchunk->subh.data_hdr->tsn); 1233 if (TSN_lte(tsn, ctsn)) { 1234 list_del_init(&tchunk->transmitted_list); 1235 sctp_chunk_free(tchunk); 1236 } 1237 } 1238 1239 /* ii) Set rwnd equal to the newly received a_rwnd minus the 1240 * number of bytes still outstanding after processing the 1241 * Cumulative TSN Ack and the Gap Ack Blocks. 1242 */ 1243 1244 sack_a_rwnd = ntohl(sack->a_rwnd); 1245 outstanding = q->outstanding_bytes; 1246 1247 if (outstanding < sack_a_rwnd) 1248 sack_a_rwnd -= outstanding; 1249 else 1250 sack_a_rwnd = 0; 1251 1252 asoc->peer.rwnd = sack_a_rwnd; 1253 1254 sctp_generate_fwdtsn(q, sack_ctsn); 1255 1256 SCTP_DEBUG_PRINTK("%s: sack Cumulative TSN Ack is 0x%x.\n", 1257 __func__, sack_ctsn); 1258 SCTP_DEBUG_PRINTK("%s: Cumulative TSN Ack of association, " 1259 "%p is 0x%x. Adv peer ack point: 0x%x\n", 1260 __func__, asoc, ctsn, asoc->adv_peer_ack_point); 1261 1262 /* See if all chunks are acked. 1263 * Make sure the empty queue handler will get run later. 1264 */ 1265 q->empty = (list_empty(&q->out_chunk_list) && 1266 list_empty(&q->retransmit)); 1267 if (!q->empty) 1268 goto finish; 1269 1270 list_for_each_entry(transport, transport_list, transports) { 1271 q->empty = q->empty && list_empty(&transport->transmitted); 1272 if (!q->empty) 1273 goto finish; 1274 } 1275 1276 SCTP_DEBUG_PRINTK("sack queue is empty.\n"); 1277 finish: 1278 return q->empty; 1279 } 1280 1281 /* Is the outqueue empty? */ 1282 int sctp_outq_is_empty(const struct sctp_outq *q) 1283 { 1284 return q->empty; 1285 } 1286 1287 /******************************************************************** 1288 * 2nd Level Abstractions 1289 ********************************************************************/ 1290 1291 /* Go through a transport's transmitted list or the association's retransmit 1292 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked. 1293 * The retransmit list will not have an associated transport. 1294 * 1295 * I added coherent debug information output. --xguo 1296 * 1297 * Instead of printing 'sacked' or 'kept' for each TSN on the 1298 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5. 1299 * KEPT TSN6-TSN7, etc. 1300 */ 1301 static void sctp_check_transmitted(struct sctp_outq *q, 1302 struct list_head *transmitted_queue, 1303 struct sctp_transport *transport, 1304 struct sctp_sackhdr *sack, 1305 __u32 highest_new_tsn_in_sack) 1306 { 1307 struct list_head *lchunk; 1308 struct sctp_chunk *tchunk; 1309 struct list_head tlist; 1310 __u32 tsn; 1311 __u32 sack_ctsn; 1312 __u32 rtt; 1313 __u8 restart_timer = 0; 1314 int bytes_acked = 0; 1315 int migrate_bytes = 0; 1316 1317 /* These state variables are for coherent debug output. --xguo */ 1318 1319 #if SCTP_DEBUG 1320 __u32 dbg_ack_tsn = 0; /* An ACKed TSN range starts here... */ 1321 __u32 dbg_last_ack_tsn = 0; /* ...and finishes here. */ 1322 __u32 dbg_kept_tsn = 0; /* An un-ACKed range starts here... */ 1323 __u32 dbg_last_kept_tsn = 0; /* ...and finishes here. */ 1324 1325 /* 0 : The last TSN was ACKed. 1326 * 1 : The last TSN was NOT ACKed (i.e. KEPT). 1327 * -1: We need to initialize. 1328 */ 1329 int dbg_prt_state = -1; 1330 #endif /* SCTP_DEBUG */ 1331 1332 sack_ctsn = ntohl(sack->cum_tsn_ack); 1333 1334 INIT_LIST_HEAD(&tlist); 1335 1336 /* The while loop will skip empty transmitted queues. */ 1337 while (NULL != (lchunk = sctp_list_dequeue(transmitted_queue))) { 1338 tchunk = list_entry(lchunk, struct sctp_chunk, 1339 transmitted_list); 1340 1341 if (sctp_chunk_abandoned(tchunk)) { 1342 /* Move the chunk to abandoned list. */ 1343 sctp_insert_list(&q->abandoned, lchunk); 1344 1345 /* If this chunk has not been acked, stop 1346 * considering it as 'outstanding'. 1347 */ 1348 if (!tchunk->tsn_gap_acked) { 1349 if (tchunk->transport) 1350 tchunk->transport->flight_size -= 1351 sctp_data_size(tchunk); 1352 q->outstanding_bytes -= sctp_data_size(tchunk); 1353 } 1354 continue; 1355 } 1356 1357 tsn = ntohl(tchunk->subh.data_hdr->tsn); 1358 if (sctp_acked(sack, tsn)) { 1359 /* If this queue is the retransmit queue, the 1360 * retransmit timer has already reclaimed 1361 * the outstanding bytes for this chunk, so only 1362 * count bytes associated with a transport. 1363 */ 1364 if (transport) { 1365 /* If this chunk is being used for RTT 1366 * measurement, calculate the RTT and update 1367 * the RTO using this value. 1368 * 1369 * 6.3.1 C5) Karn's algorithm: RTT measurements 1370 * MUST NOT be made using packets that were 1371 * retransmitted (and thus for which it is 1372 * ambiguous whether the reply was for the 1373 * first instance of the packet or a later 1374 * instance). 1375 */ 1376 if (!tchunk->tsn_gap_acked && 1377 !tchunk->resent && 1378 tchunk->rtt_in_progress) { 1379 tchunk->rtt_in_progress = 0; 1380 rtt = jiffies - tchunk->sent_at; 1381 sctp_transport_update_rto(transport, 1382 rtt); 1383 } 1384 } 1385 1386 /* If the chunk hasn't been marked as ACKED, 1387 * mark it and account bytes_acked if the 1388 * chunk had a valid transport (it will not 1389 * have a transport if ASCONF had deleted it 1390 * while DATA was outstanding). 1391 */ 1392 if (!tchunk->tsn_gap_acked) { 1393 tchunk->tsn_gap_acked = 1; 1394 bytes_acked += sctp_data_size(tchunk); 1395 if (!tchunk->transport) 1396 migrate_bytes += sctp_data_size(tchunk); 1397 } 1398 1399 if (TSN_lte(tsn, sack_ctsn)) { 1400 /* RFC 2960 6.3.2 Retransmission Timer Rules 1401 * 1402 * R3) Whenever a SACK is received 1403 * that acknowledges the DATA chunk 1404 * with the earliest outstanding TSN 1405 * for that address, restart T3-rtx 1406 * timer for that address with its 1407 * current RTO. 1408 */ 1409 restart_timer = 1; 1410 1411 if (!tchunk->tsn_gap_acked) { 1412 /* 1413 * SFR-CACC algorithm: 1414 * 2) If the SACK contains gap acks 1415 * and the flag CHANGEOVER_ACTIVE is 1416 * set the receiver of the SACK MUST 1417 * take the following action: 1418 * 1419 * B) For each TSN t being acked that 1420 * has not been acked in any SACK so 1421 * far, set cacc_saw_newack to 1 for 1422 * the destination that the TSN was 1423 * sent to. 1424 */ 1425 if (transport && 1426 sack->num_gap_ack_blocks && 1427 q->asoc->peer.primary_path->cacc. 1428 changeover_active) 1429 transport->cacc.cacc_saw_newack 1430 = 1; 1431 } 1432 1433 list_add_tail(&tchunk->transmitted_list, 1434 &q->sacked); 1435 } else { 1436 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2 1437 * M2) Each time a SACK arrives reporting 1438 * 'Stray DATA chunk(s)' record the highest TSN 1439 * reported as newly acknowledged, call this 1440 * value 'HighestTSNinSack'. A newly 1441 * acknowledged DATA chunk is one not 1442 * previously acknowledged in a SACK. 1443 * 1444 * When the SCTP sender of data receives a SACK 1445 * chunk that acknowledges, for the first time, 1446 * the receipt of a DATA chunk, all the still 1447 * unacknowledged DATA chunks whose TSN is 1448 * older than that newly acknowledged DATA 1449 * chunk, are qualified as 'Stray DATA chunks'. 1450 */ 1451 list_add_tail(lchunk, &tlist); 1452 } 1453 1454 #if SCTP_DEBUG 1455 switch (dbg_prt_state) { 1456 case 0: /* last TSN was ACKed */ 1457 if (dbg_last_ack_tsn + 1 == tsn) { 1458 /* This TSN belongs to the 1459 * current ACK range. 1460 */ 1461 break; 1462 } 1463 1464 if (dbg_last_ack_tsn != dbg_ack_tsn) { 1465 /* Display the end of the 1466 * current range. 1467 */ 1468 SCTP_DEBUG_PRINTK("-%08x", 1469 dbg_last_ack_tsn); 1470 } 1471 1472 /* Start a new range. */ 1473 SCTP_DEBUG_PRINTK(",%08x", tsn); 1474 dbg_ack_tsn = tsn; 1475 break; 1476 1477 case 1: /* The last TSN was NOT ACKed. */ 1478 if (dbg_last_kept_tsn != dbg_kept_tsn) { 1479 /* Display the end of current range. */ 1480 SCTP_DEBUG_PRINTK("-%08x", 1481 dbg_last_kept_tsn); 1482 } 1483 1484 SCTP_DEBUG_PRINTK("\n"); 1485 1486 /* FALL THROUGH... */ 1487 default: 1488 /* This is the first-ever TSN we examined. */ 1489 /* Start a new range of ACK-ed TSNs. */ 1490 SCTP_DEBUG_PRINTK("ACKed: %08x", tsn); 1491 dbg_prt_state = 0; 1492 dbg_ack_tsn = tsn; 1493 } 1494 1495 dbg_last_ack_tsn = tsn; 1496 #endif /* SCTP_DEBUG */ 1497 1498 } else { 1499 if (tchunk->tsn_gap_acked) { 1500 SCTP_DEBUG_PRINTK("%s: Receiver reneged on " 1501 "data TSN: 0x%x\n", 1502 __func__, 1503 tsn); 1504 tchunk->tsn_gap_acked = 0; 1505 1506 if (tchunk->transport) 1507 bytes_acked -= sctp_data_size(tchunk); 1508 1509 /* RFC 2960 6.3.2 Retransmission Timer Rules 1510 * 1511 * R4) Whenever a SACK is received missing a 1512 * TSN that was previously acknowledged via a 1513 * Gap Ack Block, start T3-rtx for the 1514 * destination address to which the DATA 1515 * chunk was originally 1516 * transmitted if it is not already running. 1517 */ 1518 restart_timer = 1; 1519 } 1520 1521 list_add_tail(lchunk, &tlist); 1522 1523 #if SCTP_DEBUG 1524 /* See the above comments on ACK-ed TSNs. */ 1525 switch (dbg_prt_state) { 1526 case 1: 1527 if (dbg_last_kept_tsn + 1 == tsn) 1528 break; 1529 1530 if (dbg_last_kept_tsn != dbg_kept_tsn) 1531 SCTP_DEBUG_PRINTK("-%08x", 1532 dbg_last_kept_tsn); 1533 1534 SCTP_DEBUG_PRINTK(",%08x", tsn); 1535 dbg_kept_tsn = tsn; 1536 break; 1537 1538 case 0: 1539 if (dbg_last_ack_tsn != dbg_ack_tsn) 1540 SCTP_DEBUG_PRINTK("-%08x", 1541 dbg_last_ack_tsn); 1542 SCTP_DEBUG_PRINTK("\n"); 1543 1544 /* FALL THROUGH... */ 1545 default: 1546 SCTP_DEBUG_PRINTK("KEPT: %08x",tsn); 1547 dbg_prt_state = 1; 1548 dbg_kept_tsn = tsn; 1549 } 1550 1551 dbg_last_kept_tsn = tsn; 1552 #endif /* SCTP_DEBUG */ 1553 } 1554 } 1555 1556 #if SCTP_DEBUG 1557 /* Finish off the last range, displaying its ending TSN. */ 1558 switch (dbg_prt_state) { 1559 case 0: 1560 if (dbg_last_ack_tsn != dbg_ack_tsn) { 1561 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_ack_tsn); 1562 } else { 1563 SCTP_DEBUG_PRINTK("\n"); 1564 } 1565 break; 1566 1567 case 1: 1568 if (dbg_last_kept_tsn != dbg_kept_tsn) { 1569 SCTP_DEBUG_PRINTK("-%08x\n", dbg_last_kept_tsn); 1570 } else { 1571 SCTP_DEBUG_PRINTK("\n"); 1572 } 1573 } 1574 #endif /* SCTP_DEBUG */ 1575 if (transport) { 1576 if (bytes_acked) { 1577 /* We may have counted DATA that was migrated 1578 * to this transport due to DEL-IP operation. 1579 * Subtract those bytes, since the were never 1580 * send on this transport and shouldn't be 1581 * credited to this transport. 1582 */ 1583 bytes_acked -= migrate_bytes; 1584 1585 /* 8.2. When an outstanding TSN is acknowledged, 1586 * the endpoint shall clear the error counter of 1587 * the destination transport address to which the 1588 * DATA chunk was last sent. 1589 * The association's overall error counter is 1590 * also cleared. 1591 */ 1592 transport->error_count = 0; 1593 transport->asoc->overall_error_count = 0; 1594 1595 /* Mark the destination transport address as 1596 * active if it is not so marked. 1597 */ 1598 if ((transport->state == SCTP_INACTIVE) || 1599 (transport->state == SCTP_UNCONFIRMED)) { 1600 sctp_assoc_control_transport( 1601 transport->asoc, 1602 transport, 1603 SCTP_TRANSPORT_UP, 1604 SCTP_RECEIVED_SACK); 1605 } 1606 1607 sctp_transport_raise_cwnd(transport, sack_ctsn, 1608 bytes_acked); 1609 1610 transport->flight_size -= bytes_acked; 1611 if (transport->flight_size == 0) 1612 transport->partial_bytes_acked = 0; 1613 q->outstanding_bytes -= bytes_acked + migrate_bytes; 1614 } else { 1615 /* RFC 2960 6.1, sctpimpguide-06 2.15.2 1616 * When a sender is doing zero window probing, it 1617 * should not timeout the association if it continues 1618 * to receive new packets from the receiver. The 1619 * reason is that the receiver MAY keep its window 1620 * closed for an indefinite time. 1621 * A sender is doing zero window probing when the 1622 * receiver's advertised window is zero, and there is 1623 * only one data chunk in flight to the receiver. 1624 */ 1625 if (!q->asoc->peer.rwnd && 1626 !list_empty(&tlist) && 1627 (sack_ctsn+2 == q->asoc->next_tsn)) { 1628 SCTP_DEBUG_PRINTK("%s: SACK received for zero " 1629 "window probe: %u\n", 1630 __func__, sack_ctsn); 1631 q->asoc->overall_error_count = 0; 1632 transport->error_count = 0; 1633 } 1634 } 1635 1636 /* RFC 2960 6.3.2 Retransmission Timer Rules 1637 * 1638 * R2) Whenever all outstanding data sent to an address have 1639 * been acknowledged, turn off the T3-rtx timer of that 1640 * address. 1641 */ 1642 if (!transport->flight_size) { 1643 if (timer_pending(&transport->T3_rtx_timer) && 1644 del_timer(&transport->T3_rtx_timer)) { 1645 sctp_transport_put(transport); 1646 } 1647 } else if (restart_timer) { 1648 if (!mod_timer(&transport->T3_rtx_timer, 1649 jiffies + transport->rto)) 1650 sctp_transport_hold(transport); 1651 } 1652 } 1653 1654 list_splice(&tlist, transmitted_queue); 1655 } 1656 1657 /* Mark chunks as missing and consequently may get retransmitted. */ 1658 static void sctp_mark_missing(struct sctp_outq *q, 1659 struct list_head *transmitted_queue, 1660 struct sctp_transport *transport, 1661 __u32 highest_new_tsn_in_sack, 1662 int count_of_newacks) 1663 { 1664 struct sctp_chunk *chunk; 1665 __u32 tsn; 1666 char do_fast_retransmit = 0; 1667 struct sctp_transport *primary = q->asoc->peer.primary_path; 1668 1669 list_for_each_entry(chunk, transmitted_queue, transmitted_list) { 1670 1671 tsn = ntohl(chunk->subh.data_hdr->tsn); 1672 1673 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all 1674 * 'Unacknowledged TSN's', if the TSN number of an 1675 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack' 1676 * value, increment the 'TSN.Missing.Report' count on that 1677 * chunk if it has NOT been fast retransmitted or marked for 1678 * fast retransmit already. 1679 */ 1680 if (chunk->fast_retransmit == SCTP_CAN_FRTX && 1681 !chunk->tsn_gap_acked && 1682 TSN_lt(tsn, highest_new_tsn_in_sack)) { 1683 1684 /* SFR-CACC may require us to skip marking 1685 * this chunk as missing. 1686 */ 1687 if (!transport || !sctp_cacc_skip(primary, transport, 1688 count_of_newacks, tsn)) { 1689 chunk->tsn_missing_report++; 1690 1691 SCTP_DEBUG_PRINTK( 1692 "%s: TSN 0x%x missing counter: %d\n", 1693 __func__, tsn, 1694 chunk->tsn_missing_report); 1695 } 1696 } 1697 /* 1698 * M4) If any DATA chunk is found to have a 1699 * 'TSN.Missing.Report' 1700 * value larger than or equal to 3, mark that chunk for 1701 * retransmission and start the fast retransmit procedure. 1702 */ 1703 1704 if (chunk->tsn_missing_report >= 3) { 1705 chunk->fast_retransmit = SCTP_NEED_FRTX; 1706 do_fast_retransmit = 1; 1707 } 1708 } 1709 1710 if (transport) { 1711 if (do_fast_retransmit) 1712 sctp_retransmit(q, transport, SCTP_RTXR_FAST_RTX); 1713 1714 SCTP_DEBUG_PRINTK("%s: transport: %p, cwnd: %d, " 1715 "ssthresh: %d, flight_size: %d, pba: %d\n", 1716 __func__, transport, transport->cwnd, 1717 transport->ssthresh, transport->flight_size, 1718 transport->partial_bytes_acked); 1719 } 1720 } 1721 1722 /* Is the given TSN acked by this packet? */ 1723 static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn) 1724 { 1725 int i; 1726 sctp_sack_variable_t *frags; 1727 __u16 gap; 1728 __u32 ctsn = ntohl(sack->cum_tsn_ack); 1729 1730 if (TSN_lte(tsn, ctsn)) 1731 goto pass; 1732 1733 /* 3.3.4 Selective Acknowledgement (SACK) (3): 1734 * 1735 * Gap Ack Blocks: 1736 * These fields contain the Gap Ack Blocks. They are repeated 1737 * for each Gap Ack Block up to the number of Gap Ack Blocks 1738 * defined in the Number of Gap Ack Blocks field. All DATA 1739 * chunks with TSNs greater than or equal to (Cumulative TSN 1740 * Ack + Gap Ack Block Start) and less than or equal to 1741 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack 1742 * Block are assumed to have been received correctly. 1743 */ 1744 1745 frags = sack->variable; 1746 gap = tsn - ctsn; 1747 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); ++i) { 1748 if (TSN_lte(ntohs(frags[i].gab.start), gap) && 1749 TSN_lte(gap, ntohs(frags[i].gab.end))) 1750 goto pass; 1751 } 1752 1753 return 0; 1754 pass: 1755 return 1; 1756 } 1757 1758 static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip *skiplist, 1759 int nskips, __be16 stream) 1760 { 1761 int i; 1762 1763 for (i = 0; i < nskips; i++) { 1764 if (skiplist[i].stream == stream) 1765 return i; 1766 } 1767 return i; 1768 } 1769 1770 /* Create and add a fwdtsn chunk to the outq's control queue if needed. */ 1771 static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 ctsn) 1772 { 1773 struct sctp_association *asoc = q->asoc; 1774 struct sctp_chunk *ftsn_chunk = NULL; 1775 struct sctp_fwdtsn_skip ftsn_skip_arr[10]; 1776 int nskips = 0; 1777 int skip_pos = 0; 1778 __u32 tsn; 1779 struct sctp_chunk *chunk; 1780 struct list_head *lchunk, *temp; 1781 1782 if (!asoc->peer.prsctp_capable) 1783 return; 1784 1785 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the 1786 * received SACK. 1787 * 1788 * If (Advanced.Peer.Ack.Point < SackCumAck), then update 1789 * Advanced.Peer.Ack.Point to be equal to SackCumAck. 1790 */ 1791 if (TSN_lt(asoc->adv_peer_ack_point, ctsn)) 1792 asoc->adv_peer_ack_point = ctsn; 1793 1794 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point" 1795 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as 1796 * the chunk next in the out-queue space is marked as "abandoned" as 1797 * shown in the following example: 1798 * 1799 * Assuming that a SACK arrived with the Cumulative TSN ACK 102 1800 * and the Advanced.Peer.Ack.Point is updated to this value: 1801 * 1802 * out-queue at the end of ==> out-queue after Adv.Ack.Point 1803 * normal SACK processing local advancement 1804 * ... ... 1805 * Adv.Ack.Pt-> 102 acked 102 acked 1806 * 103 abandoned 103 abandoned 1807 * 104 abandoned Adv.Ack.P-> 104 abandoned 1808 * 105 105 1809 * 106 acked 106 acked 1810 * ... ... 1811 * 1812 * In this example, the data sender successfully advanced the 1813 * "Advanced.Peer.Ack.Point" from 102 to 104 locally. 1814 */ 1815 list_for_each_safe(lchunk, temp, &q->abandoned) { 1816 chunk = list_entry(lchunk, struct sctp_chunk, 1817 transmitted_list); 1818 tsn = ntohl(chunk->subh.data_hdr->tsn); 1819 1820 /* Remove any chunks in the abandoned queue that are acked by 1821 * the ctsn. 1822 */ 1823 if (TSN_lte(tsn, ctsn)) { 1824 list_del_init(lchunk); 1825 sctp_chunk_free(chunk); 1826 } else { 1827 if (TSN_lte(tsn, asoc->adv_peer_ack_point+1)) { 1828 asoc->adv_peer_ack_point = tsn; 1829 if (chunk->chunk_hdr->flags & 1830 SCTP_DATA_UNORDERED) 1831 continue; 1832 skip_pos = sctp_get_skip_pos(&ftsn_skip_arr[0], 1833 nskips, 1834 chunk->subh.data_hdr->stream); 1835 ftsn_skip_arr[skip_pos].stream = 1836 chunk->subh.data_hdr->stream; 1837 ftsn_skip_arr[skip_pos].ssn = 1838 chunk->subh.data_hdr->ssn; 1839 if (skip_pos == nskips) 1840 nskips++; 1841 if (nskips == 10) 1842 break; 1843 } else 1844 break; 1845 } 1846 } 1847 1848 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point" 1849 * is greater than the Cumulative TSN ACK carried in the received 1850 * SACK, the data sender MUST send the data receiver a FORWARD TSN 1851 * chunk containing the latest value of the 1852 * "Advanced.Peer.Ack.Point". 1853 * 1854 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD 1855 * list each stream and sequence number in the forwarded TSN. This 1856 * information will enable the receiver to easily find any 1857 * stranded TSN's waiting on stream reorder queues. Each stream 1858 * SHOULD only be reported once; this means that if multiple 1859 * abandoned messages occur in the same stream then only the 1860 * highest abandoned stream sequence number is reported. If the 1861 * total size of the FORWARD TSN does NOT fit in a single MTU then 1862 * the sender of the FORWARD TSN SHOULD lower the 1863 * Advanced.Peer.Ack.Point to the last TSN that will fit in a 1864 * single MTU. 1865 */ 1866 if (asoc->adv_peer_ack_point > ctsn) 1867 ftsn_chunk = sctp_make_fwdtsn(asoc, asoc->adv_peer_ack_point, 1868 nskips, &ftsn_skip_arr[0]); 1869 1870 if (ftsn_chunk) { 1871 list_add_tail(&ftsn_chunk->list, &q->control_chunk_list); 1872 SCTP_INC_STATS(SCTP_MIB_OUTCTRLCHUNKS); 1873 } 1874 } 1875