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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 50 51 #include <linux/types.h> 52 #include <linux/list.h> /* For struct list_head */ 53 #include <linux/socket.h> 54 #include <linux/ip.h> 55 #include <linux/slab.h> 56 #include <net/sock.h> /* For skb_set_owner_w */ 57 58 #include <net/sctp/sctp.h> 59 #include <net/sctp/sm.h> 60 61 /* Declare internal functions here. */ 62 static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn); 63 static void sctp_check_transmitted(struct sctp_outq *q, 64 struct list_head *transmitted_queue, 65 struct sctp_transport *transport, 66 union sctp_addr *saddr, 67 struct sctp_sackhdr *sack, 68 __u32 *highest_new_tsn); 69 70 static void sctp_mark_missing(struct sctp_outq *q, 71 struct list_head *transmitted_queue, 72 struct sctp_transport *transport, 73 __u32 highest_new_tsn, 74 int count_of_newacks); 75 76 static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 sack_ctsn); 77 78 static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout); 79 80 /* Add data to the front of the queue. */ 81 static inline void sctp_outq_head_data(struct sctp_outq *q, 82 struct sctp_chunk *ch) 83 { 84 list_add(&ch->list, &q->out_chunk_list); 85 q->out_qlen += ch->skb->len; 86 } 87 88 /* Take data from the front of the queue. */ 89 static inline struct sctp_chunk *sctp_outq_dequeue_data(struct sctp_outq *q) 90 { 91 struct sctp_chunk *ch = NULL; 92 93 if (!list_empty(&q->out_chunk_list)) { 94 struct list_head *entry = q->out_chunk_list.next; 95 96 ch = list_entry(entry, struct sctp_chunk, list); 97 list_del_init(entry); 98 q->out_qlen -= ch->skb->len; 99 } 100 return ch; 101 } 102 /* Add data chunk to the end of the queue. */ 103 static inline void sctp_outq_tail_data(struct sctp_outq *q, 104 struct sctp_chunk *ch) 105 { 106 list_add_tail(&ch->list, &q->out_chunk_list); 107 q->out_qlen += ch->skb->len; 108 } 109 110 /* 111 * SFR-CACC algorithm: 112 * D) If count_of_newacks is greater than or equal to 2 113 * and t was not sent to the current primary then the 114 * sender MUST NOT increment missing report count for t. 115 */ 116 static inline int sctp_cacc_skip_3_1_d(struct sctp_transport *primary, 117 struct sctp_transport *transport, 118 int count_of_newacks) 119 { 120 if (count_of_newacks >=2 && transport != primary) 121 return 1; 122 return 0; 123 } 124 125 /* 126 * SFR-CACC algorithm: 127 * F) If count_of_newacks is less than 2, let d be the 128 * destination to which t was sent. If cacc_saw_newack 129 * is 0 for destination d, then the sender MUST NOT 130 * increment missing report count for t. 131 */ 132 static inline int sctp_cacc_skip_3_1_f(struct sctp_transport *transport, 133 int count_of_newacks) 134 { 135 if (count_of_newacks < 2 && 136 (transport && !transport->cacc.cacc_saw_newack)) 137 return 1; 138 return 0; 139 } 140 141 /* 142 * SFR-CACC algorithm: 143 * 3.1) If CYCLING_CHANGEOVER is 0, the sender SHOULD 144 * execute steps C, D, F. 145 * 146 * C has been implemented in sctp_outq_sack 147 */ 148 static inline int sctp_cacc_skip_3_1(struct sctp_transport *primary, 149 struct sctp_transport *transport, 150 int count_of_newacks) 151 { 152 if (!primary->cacc.cycling_changeover) { 153 if (sctp_cacc_skip_3_1_d(primary, transport, count_of_newacks)) 154 return 1; 155 if (sctp_cacc_skip_3_1_f(transport, count_of_newacks)) 156 return 1; 157 return 0; 158 } 159 return 0; 160 } 161 162 /* 163 * SFR-CACC algorithm: 164 * 3.2) Else if CYCLING_CHANGEOVER is 1, and t is less 165 * than next_tsn_at_change of the current primary, then 166 * the sender MUST NOT increment missing report count 167 * for t. 168 */ 169 static inline int sctp_cacc_skip_3_2(struct sctp_transport *primary, __u32 tsn) 170 { 171 if (primary->cacc.cycling_changeover && 172 TSN_lt(tsn, primary->cacc.next_tsn_at_change)) 173 return 1; 174 return 0; 175 } 176 177 /* 178 * SFR-CACC algorithm: 179 * 3) If the missing report count for TSN t is to be 180 * incremented according to [RFC2960] and 181 * [SCTP_STEWART-2002], and CHANGEOVER_ACTIVE is set, 182 * then the sender MUST further execute steps 3.1 and 183 * 3.2 to determine if the missing report count for 184 * TSN t SHOULD NOT be incremented. 185 * 186 * 3.3) If 3.1 and 3.2 do not dictate that the missing 187 * report count for t should not be incremented, then 188 * the sender SHOULD increment missing report count for 189 * t (according to [RFC2960] and [SCTP_STEWART_2002]). 190 */ 191 static inline int sctp_cacc_skip(struct sctp_transport *primary, 192 struct sctp_transport *transport, 193 int count_of_newacks, 194 __u32 tsn) 195 { 196 if (primary->cacc.changeover_active && 197 (sctp_cacc_skip_3_1(primary, transport, count_of_newacks) || 198 sctp_cacc_skip_3_2(primary, tsn))) 199 return 1; 200 return 0; 201 } 202 203 /* Initialize an existing sctp_outq. This does the boring stuff. 204 * You still need to define handlers if you really want to DO 205 * something with this structure... 206 */ 207 void sctp_outq_init(struct sctp_association *asoc, struct sctp_outq *q) 208 { 209 q->asoc = asoc; 210 INIT_LIST_HEAD(&q->out_chunk_list); 211 INIT_LIST_HEAD(&q->control_chunk_list); 212 INIT_LIST_HEAD(&q->retransmit); 213 INIT_LIST_HEAD(&q->sacked); 214 INIT_LIST_HEAD(&q->abandoned); 215 216 q->fast_rtx = 0; 217 q->outstanding_bytes = 0; 218 q->empty = 1; 219 q->cork = 0; 220 q->out_qlen = 0; 221 } 222 223 /* Free the outqueue structure and any related pending chunks. 224 */ 225 static void __sctp_outq_teardown(struct sctp_outq *q) 226 { 227 struct sctp_transport *transport; 228 struct list_head *lchunk, *temp; 229 struct sctp_chunk *chunk, *tmp; 230 231 /* Throw away unacknowledged chunks. */ 232 list_for_each_entry(transport, &q->asoc->peer.transport_addr_list, 233 transports) { 234 while ((lchunk = sctp_list_dequeue(&transport->transmitted)) != NULL) { 235 chunk = list_entry(lchunk, struct sctp_chunk, 236 transmitted_list); 237 /* Mark as part of a failed message. */ 238 sctp_chunk_fail(chunk, q->error); 239 sctp_chunk_free(chunk); 240 } 241 } 242 243 /* Throw away chunks that have been gap ACKed. */ 244 list_for_each_safe(lchunk, temp, &q->sacked) { 245 list_del_init(lchunk); 246 chunk = list_entry(lchunk, struct sctp_chunk, 247 transmitted_list); 248 sctp_chunk_fail(chunk, q->error); 249 sctp_chunk_free(chunk); 250 } 251 252 /* Throw away any chunks in the retransmit queue. */ 253 list_for_each_safe(lchunk, temp, &q->retransmit) { 254 list_del_init(lchunk); 255 chunk = list_entry(lchunk, struct sctp_chunk, 256 transmitted_list); 257 sctp_chunk_fail(chunk, q->error); 258 sctp_chunk_free(chunk); 259 } 260 261 /* Throw away any chunks that are in the abandoned queue. */ 262 list_for_each_safe(lchunk, temp, &q->abandoned) { 263 list_del_init(lchunk); 264 chunk = list_entry(lchunk, struct sctp_chunk, 265 transmitted_list); 266 sctp_chunk_fail(chunk, q->error); 267 sctp_chunk_free(chunk); 268 } 269 270 /* Throw away any leftover data chunks. */ 271 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) { 272 273 /* Mark as send failure. */ 274 sctp_chunk_fail(chunk, q->error); 275 sctp_chunk_free(chunk); 276 } 277 278 /* Throw away any leftover control chunks. */ 279 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) { 280 list_del_init(&chunk->list); 281 sctp_chunk_free(chunk); 282 } 283 } 284 285 void sctp_outq_teardown(struct sctp_outq *q) 286 { 287 __sctp_outq_teardown(q); 288 sctp_outq_init(q->asoc, q); 289 } 290 291 /* Free the outqueue structure and any related pending chunks. */ 292 void sctp_outq_free(struct sctp_outq *q) 293 { 294 /* Throw away leftover chunks. */ 295 __sctp_outq_teardown(q); 296 } 297 298 /* Put a new chunk in an sctp_outq. */ 299 int sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk) 300 { 301 struct net *net = sock_net(q->asoc->base.sk); 302 int error = 0; 303 304 SCTP_DEBUG_PRINTK("sctp_outq_tail(%p, %p[%s])\n", 305 q, chunk, chunk && chunk->chunk_hdr ? 306 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) 307 : "Illegal Chunk"); 308 309 /* If it is data, queue it up, otherwise, send it 310 * immediately. 311 */ 312 if (sctp_chunk_is_data(chunk)) { 313 /* Is it OK to queue data chunks? */ 314 /* From 9. Termination of Association 315 * 316 * When either endpoint performs a shutdown, the 317 * association on each peer will stop accepting new 318 * data from its user and only deliver data in queue 319 * at the time of sending or receiving the SHUTDOWN 320 * chunk. 321 */ 322 switch (q->asoc->state) { 323 case SCTP_STATE_CLOSED: 324 case SCTP_STATE_SHUTDOWN_PENDING: 325 case SCTP_STATE_SHUTDOWN_SENT: 326 case SCTP_STATE_SHUTDOWN_RECEIVED: 327 case SCTP_STATE_SHUTDOWN_ACK_SENT: 328 /* Cannot send after transport endpoint shutdown */ 329 error = -ESHUTDOWN; 330 break; 331 332 default: 333 SCTP_DEBUG_PRINTK("outqueueing (%p, %p[%s])\n", 334 q, chunk, chunk && chunk->chunk_hdr ? 335 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) 336 : "Illegal Chunk"); 337 338 sctp_outq_tail_data(q, chunk); 339 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) 340 SCTP_INC_STATS(net, SCTP_MIB_OUTUNORDERCHUNKS); 341 else 342 SCTP_INC_STATS(net, SCTP_MIB_OUTORDERCHUNKS); 343 q->empty = 0; 344 break; 345 } 346 } else { 347 list_add_tail(&chunk->list, &q->control_chunk_list); 348 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 349 } 350 351 if (error < 0) 352 return error; 353 354 if (!q->cork) 355 error = sctp_outq_flush(q, 0); 356 357 return error; 358 } 359 360 /* Insert a chunk into the sorted list based on the TSNs. The retransmit list 361 * and the abandoned list are in ascending order. 362 */ 363 static void sctp_insert_list(struct list_head *head, struct list_head *new) 364 { 365 struct list_head *pos; 366 struct sctp_chunk *nchunk, *lchunk; 367 __u32 ntsn, ltsn; 368 int done = 0; 369 370 nchunk = list_entry(new, struct sctp_chunk, transmitted_list); 371 ntsn = ntohl(nchunk->subh.data_hdr->tsn); 372 373 list_for_each(pos, head) { 374 lchunk = list_entry(pos, struct sctp_chunk, transmitted_list); 375 ltsn = ntohl(lchunk->subh.data_hdr->tsn); 376 if (TSN_lt(ntsn, ltsn)) { 377 list_add(new, pos->prev); 378 done = 1; 379 break; 380 } 381 } 382 if (!done) 383 list_add_tail(new, head); 384 } 385 386 /* Mark all the eligible packets on a transport for retransmission. */ 387 void sctp_retransmit_mark(struct sctp_outq *q, 388 struct sctp_transport *transport, 389 __u8 reason) 390 { 391 struct list_head *lchunk, *ltemp; 392 struct sctp_chunk *chunk; 393 394 /* Walk through the specified transmitted queue. */ 395 list_for_each_safe(lchunk, ltemp, &transport->transmitted) { 396 chunk = list_entry(lchunk, struct sctp_chunk, 397 transmitted_list); 398 399 /* If the chunk is abandoned, move it to abandoned list. */ 400 if (sctp_chunk_abandoned(chunk)) { 401 list_del_init(lchunk); 402 sctp_insert_list(&q->abandoned, lchunk); 403 404 /* If this chunk has not been previousely acked, 405 * stop considering it 'outstanding'. Our peer 406 * will most likely never see it since it will 407 * not be retransmitted 408 */ 409 if (!chunk->tsn_gap_acked) { 410 if (chunk->transport) 411 chunk->transport->flight_size -= 412 sctp_data_size(chunk); 413 q->outstanding_bytes -= sctp_data_size(chunk); 414 q->asoc->peer.rwnd += sctp_data_size(chunk); 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 /* RFC 2960 6.2.1 Processing a Received SACK 427 * 428 * C) Any time a DATA chunk is marked for 429 * retransmission (via either T3-rtx timer expiration 430 * (Section 6.3.3) or via fast retransmit 431 * (Section 7.2.4)), add the data size of those 432 * chunks to the rwnd. 433 */ 434 q->asoc->peer.rwnd += sctp_data_size(chunk); 435 q->outstanding_bytes -= sctp_data_size(chunk); 436 if (chunk->transport) 437 transport->flight_size -= sctp_data_size(chunk); 438 439 /* sctpimpguide-05 Section 2.8.2 440 * M5) If a T3-rtx timer expires, the 441 * 'TSN.Missing.Report' of all affected TSNs is set 442 * to 0. 443 */ 444 chunk->tsn_missing_report = 0; 445 446 /* If a chunk that is being used for RTT measurement 447 * has to be retransmitted, we cannot use this chunk 448 * anymore for RTT measurements. Reset rto_pending so 449 * that a new RTT measurement is started when a new 450 * data chunk is sent. 451 */ 452 if (chunk->rtt_in_progress) { 453 chunk->rtt_in_progress = 0; 454 transport->rto_pending = 0; 455 } 456 457 /* Move the chunk to the retransmit queue. The chunks 458 * on the retransmit queue are always kept in order. 459 */ 460 list_del_init(lchunk); 461 sctp_insert_list(&q->retransmit, lchunk); 462 } 463 } 464 465 SCTP_DEBUG_PRINTK("%s: transport: %p, reason: %d, " 466 "cwnd: %d, ssthresh: %d, flight_size: %d, " 467 "pba: %d\n", __func__, 468 transport, reason, 469 transport->cwnd, transport->ssthresh, 470 transport->flight_size, 471 transport->partial_bytes_acked); 472 473 } 474 475 /* Mark all the eligible packets on a transport for retransmission and force 476 * one packet out. 477 */ 478 void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport, 479 sctp_retransmit_reason_t reason) 480 { 481 struct net *net = sock_net(q->asoc->base.sk); 482 int error = 0; 483 484 switch(reason) { 485 case SCTP_RTXR_T3_RTX: 486 SCTP_INC_STATS(net, SCTP_MIB_T3_RETRANSMITS); 487 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_T3_RTX); 488 /* Update the retran path if the T3-rtx timer has expired for 489 * the current retran path. 490 */ 491 if (transport == transport->asoc->peer.retran_path) 492 sctp_assoc_update_retran_path(transport->asoc); 493 transport->asoc->rtx_data_chunks += 494 transport->asoc->unack_data; 495 break; 496 case SCTP_RTXR_FAST_RTX: 497 SCTP_INC_STATS(net, SCTP_MIB_FAST_RETRANSMITS); 498 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_FAST_RTX); 499 q->fast_rtx = 1; 500 break; 501 case SCTP_RTXR_PMTUD: 502 SCTP_INC_STATS(net, SCTP_MIB_PMTUD_RETRANSMITS); 503 break; 504 case SCTP_RTXR_T1_RTX: 505 SCTP_INC_STATS(net, SCTP_MIB_T1_RETRANSMITS); 506 transport->asoc->init_retries++; 507 break; 508 default: 509 BUG(); 510 } 511 512 sctp_retransmit_mark(q, transport, reason); 513 514 /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination, 515 * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by 516 * following the procedures outlined in C1 - C5. 517 */ 518 if (reason == SCTP_RTXR_T3_RTX) 519 sctp_generate_fwdtsn(q, q->asoc->ctsn_ack_point); 520 521 /* Flush the queues only on timeout, since fast_rtx is only 522 * triggered during sack processing and the queue 523 * will be flushed at the end. 524 */ 525 if (reason != SCTP_RTXR_FAST_RTX) 526 error = sctp_outq_flush(q, /* rtx_timeout */ 1); 527 528 if (error) 529 q->asoc->base.sk->sk_err = -error; 530 } 531 532 /* 533 * Transmit DATA chunks on the retransmit queue. Upon return from 534 * sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which 535 * need to be transmitted by the caller. 536 * We assume that pkt->transport has already been set. 537 * 538 * The return value is a normal kernel error return value. 539 */ 540 static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt, 541 int rtx_timeout, int *start_timer) 542 { 543 struct list_head *lqueue; 544 struct sctp_transport *transport = pkt->transport; 545 sctp_xmit_t status; 546 struct sctp_chunk *chunk, *chunk1; 547 int fast_rtx; 548 int error = 0; 549 int timer = 0; 550 int done = 0; 551 552 lqueue = &q->retransmit; 553 fast_rtx = q->fast_rtx; 554 555 /* This loop handles time-out retransmissions, fast retransmissions, 556 * and retransmissions due to opening of whindow. 557 * 558 * RFC 2960 6.3.3 Handle T3-rtx Expiration 559 * 560 * E3) Determine how many of the earliest (i.e., lowest TSN) 561 * outstanding DATA chunks for the address for which the 562 * T3-rtx has expired will fit into a single packet, subject 563 * to the MTU constraint for the path corresponding to the 564 * destination transport address to which the retransmission 565 * is being sent (this may be different from the address for 566 * which the timer expires [see Section 6.4]). Call this value 567 * K. Bundle and retransmit those K DATA chunks in a single 568 * packet to the destination endpoint. 569 * 570 * [Just to be painfully clear, if we are retransmitting 571 * because a timeout just happened, we should send only ONE 572 * packet of retransmitted data.] 573 * 574 * For fast retransmissions we also send only ONE packet. However, 575 * if we are just flushing the queue due to open window, we'll 576 * try to send as much as possible. 577 */ 578 list_for_each_entry_safe(chunk, chunk1, lqueue, transmitted_list) { 579 /* If the chunk is abandoned, move it to abandoned list. */ 580 if (sctp_chunk_abandoned(chunk)) { 581 list_del_init(&chunk->transmitted_list); 582 sctp_insert_list(&q->abandoned, 583 &chunk->transmitted_list); 584 continue; 585 } 586 587 /* Make sure that Gap Acked TSNs are not retransmitted. A 588 * simple approach is just to move such TSNs out of the 589 * way and into a 'transmitted' queue and skip to the 590 * next chunk. 591 */ 592 if (chunk->tsn_gap_acked) { 593 list_move_tail(&chunk->transmitted_list, 594 &transport->transmitted); 595 continue; 596 } 597 598 /* If we are doing fast retransmit, ignore non-fast_rtransmit 599 * chunks 600 */ 601 if (fast_rtx && !chunk->fast_retransmit) 602 continue; 603 604 redo: 605 /* Attempt to append this chunk to the packet. */ 606 status = sctp_packet_append_chunk(pkt, chunk); 607 608 switch (status) { 609 case SCTP_XMIT_PMTU_FULL: 610 if (!pkt->has_data && !pkt->has_cookie_echo) { 611 /* If this packet did not contain DATA then 612 * retransmission did not happen, so do it 613 * again. We'll ignore the error here since 614 * control chunks are already freed so there 615 * is nothing we can do. 616 */ 617 sctp_packet_transmit(pkt); 618 goto redo; 619 } 620 621 /* Send this packet. */ 622 error = sctp_packet_transmit(pkt); 623 624 /* If we are retransmitting, we should only 625 * send a single packet. 626 * Otherwise, try appending this chunk again. 627 */ 628 if (rtx_timeout || fast_rtx) 629 done = 1; 630 else 631 goto redo; 632 633 /* Bundle next chunk in the next round. */ 634 break; 635 636 case SCTP_XMIT_RWND_FULL: 637 /* Send this packet. */ 638 error = sctp_packet_transmit(pkt); 639 640 /* Stop sending DATA as there is no more room 641 * at the receiver. 642 */ 643 done = 1; 644 break; 645 646 case SCTP_XMIT_NAGLE_DELAY: 647 /* Send this packet. */ 648 error = sctp_packet_transmit(pkt); 649 650 /* Stop sending DATA because of nagle delay. */ 651 done = 1; 652 break; 653 654 default: 655 /* The append was successful, so add this chunk to 656 * the transmitted list. 657 */ 658 list_move_tail(&chunk->transmitted_list, 659 &transport->transmitted); 660 661 /* Mark the chunk as ineligible for fast retransmit 662 * after it is retransmitted. 663 */ 664 if (chunk->fast_retransmit == SCTP_NEED_FRTX) 665 chunk->fast_retransmit = SCTP_DONT_FRTX; 666 667 q->empty = 0; 668 q->asoc->stats.rtxchunks++; 669 break; 670 } 671 672 /* Set the timer if there were no errors */ 673 if (!error && !timer) 674 timer = 1; 675 676 if (done) 677 break; 678 } 679 680 /* If we are here due to a retransmit timeout or a fast 681 * retransmit and if there are any chunks left in the retransmit 682 * queue that could not fit in the PMTU sized packet, they need 683 * to be marked as ineligible for a subsequent fast retransmit. 684 */ 685 if (rtx_timeout || fast_rtx) { 686 list_for_each_entry(chunk1, lqueue, transmitted_list) { 687 if (chunk1->fast_retransmit == SCTP_NEED_FRTX) 688 chunk1->fast_retransmit = SCTP_DONT_FRTX; 689 } 690 } 691 692 *start_timer = timer; 693 694 /* Clear fast retransmit hint */ 695 if (fast_rtx) 696 q->fast_rtx = 0; 697 698 return error; 699 } 700 701 /* Cork the outqueue so queued chunks are really queued. */ 702 int sctp_outq_uncork(struct sctp_outq *q) 703 { 704 if (q->cork) 705 q->cork = 0; 706 707 return sctp_outq_flush(q, 0); 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 /* RFC 5061, 5.3 755 * F1) This means that until such time as the ASCONF 756 * containing the add is acknowledged, the sender MUST 757 * NOT use the new IP address as a source for ANY SCTP 758 * packet except on carrying an ASCONF Chunk. 759 */ 760 if (asoc->src_out_of_asoc_ok && 761 chunk->chunk_hdr->type != SCTP_CID_ASCONF) 762 continue; 763 764 list_del_init(&chunk->list); 765 766 /* Pick the right transport to use. */ 767 new_transport = chunk->transport; 768 769 if (!new_transport) { 770 /* 771 * If we have a prior transport pointer, see if 772 * the destination address of the chunk 773 * matches the destination address of the 774 * current transport. If not a match, then 775 * try to look up the transport with a given 776 * destination address. We do this because 777 * after processing ASCONFs, we may have new 778 * transports created. 779 */ 780 if (transport && 781 sctp_cmp_addr_exact(&chunk->dest, 782 &transport->ipaddr)) 783 new_transport = transport; 784 else 785 new_transport = sctp_assoc_lookup_paddr(asoc, 786 &chunk->dest); 787 788 /* if we still don't have a new transport, then 789 * use the current active path. 790 */ 791 if (!new_transport) 792 new_transport = asoc->peer.active_path; 793 } else if ((new_transport->state == SCTP_INACTIVE) || 794 (new_transport->state == SCTP_UNCONFIRMED) || 795 (new_transport->state == SCTP_PF)) { 796 /* If the chunk is Heartbeat or Heartbeat Ack, 797 * send it to chunk->transport, even if it's 798 * inactive. 799 * 800 * 3.3.6 Heartbeat Acknowledgement: 801 * ... 802 * A HEARTBEAT ACK is always sent to the source IP 803 * address of the IP datagram containing the 804 * HEARTBEAT chunk to which this ack is responding. 805 * ... 806 * 807 * ASCONF_ACKs also must be sent to the source. 808 */ 809 if (chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT && 810 chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT_ACK && 811 chunk->chunk_hdr->type != SCTP_CID_ASCONF_ACK) 812 new_transport = asoc->peer.active_path; 813 } 814 815 /* Are we switching transports? 816 * Take care of transport locks. 817 */ 818 if (new_transport != transport) { 819 transport = new_transport; 820 if (list_empty(&transport->send_ready)) { 821 list_add_tail(&transport->send_ready, 822 &transport_list); 823 } 824 packet = &transport->packet; 825 sctp_packet_config(packet, vtag, 826 asoc->peer.ecn_capable); 827 } 828 829 switch (chunk->chunk_hdr->type) { 830 /* 831 * 6.10 Bundling 832 * ... 833 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN 834 * COMPLETE with any other chunks. [Send them immediately.] 835 */ 836 case SCTP_CID_INIT: 837 case SCTP_CID_INIT_ACK: 838 case SCTP_CID_SHUTDOWN_COMPLETE: 839 sctp_packet_init(&singleton, transport, sport, dport); 840 sctp_packet_config(&singleton, vtag, 0); 841 sctp_packet_append_chunk(&singleton, chunk); 842 error = sctp_packet_transmit(&singleton); 843 if (error < 0) 844 return error; 845 break; 846 847 case SCTP_CID_ABORT: 848 if (sctp_test_T_bit(chunk)) { 849 packet->vtag = asoc->c.my_vtag; 850 } 851 /* The following chunks are "response" chunks, i.e. 852 * they are generated in response to something we 853 * received. If we are sending these, then we can 854 * send only 1 packet containing these chunks. 855 */ 856 case SCTP_CID_HEARTBEAT_ACK: 857 case SCTP_CID_SHUTDOWN_ACK: 858 case SCTP_CID_COOKIE_ACK: 859 case SCTP_CID_COOKIE_ECHO: 860 case SCTP_CID_ERROR: 861 case SCTP_CID_ECN_CWR: 862 case SCTP_CID_ASCONF_ACK: 863 one_packet = 1; 864 /* Fall through */ 865 866 case SCTP_CID_SACK: 867 case SCTP_CID_HEARTBEAT: 868 case SCTP_CID_SHUTDOWN: 869 case SCTP_CID_ECN_ECNE: 870 case SCTP_CID_ASCONF: 871 case SCTP_CID_FWD_TSN: 872 status = sctp_packet_transmit_chunk(packet, chunk, 873 one_packet); 874 if (status != SCTP_XMIT_OK) { 875 /* put the chunk back */ 876 list_add(&chunk->list, &q->control_chunk_list); 877 } else { 878 asoc->stats.octrlchunks++; 879 /* PR-SCTP C5) If a FORWARD TSN is sent, the 880 * sender MUST assure that at least one T3-rtx 881 * timer is running. 882 */ 883 if (chunk->chunk_hdr->type == SCTP_CID_FWD_TSN) 884 sctp_transport_reset_timers(transport); 885 } 886 break; 887 888 default: 889 /* We built a chunk with an illegal type! */ 890 BUG(); 891 } 892 } 893 894 if (q->asoc->src_out_of_asoc_ok) 895 goto sctp_flush_out; 896 897 /* Is it OK to send data chunks? */ 898 switch (asoc->state) { 899 case SCTP_STATE_COOKIE_ECHOED: 900 /* Only allow bundling when this packet has a COOKIE-ECHO 901 * chunk. 902 */ 903 if (!packet || !packet->has_cookie_echo) 904 break; 905 906 /* fallthru */ 907 case SCTP_STATE_ESTABLISHED: 908 case SCTP_STATE_SHUTDOWN_PENDING: 909 case SCTP_STATE_SHUTDOWN_RECEIVED: 910 /* 911 * RFC 2960 6.1 Transmission of DATA Chunks 912 * 913 * C) When the time comes for the sender to transmit, 914 * before sending new DATA chunks, the sender MUST 915 * first transmit any outstanding DATA chunks which 916 * are marked for retransmission (limited by the 917 * current cwnd). 918 */ 919 if (!list_empty(&q->retransmit)) { 920 if (asoc->peer.retran_path->state == SCTP_UNCONFIRMED) 921 goto sctp_flush_out; 922 if (transport == asoc->peer.retran_path) 923 goto retran; 924 925 /* Switch transports & prepare the packet. */ 926 927 transport = asoc->peer.retran_path; 928 929 if (list_empty(&transport->send_ready)) { 930 list_add_tail(&transport->send_ready, 931 &transport_list); 932 } 933 934 packet = &transport->packet; 935 sctp_packet_config(packet, vtag, 936 asoc->peer.ecn_capable); 937 retran: 938 error = sctp_outq_flush_rtx(q, packet, 939 rtx_timeout, &start_timer); 940 941 if (start_timer) 942 sctp_transport_reset_timers(transport); 943 944 /* This can happen on COOKIE-ECHO resend. Only 945 * one chunk can get bundled with a COOKIE-ECHO. 946 */ 947 if (packet->has_cookie_echo) 948 goto sctp_flush_out; 949 950 /* Don't send new data if there is still data 951 * waiting to retransmit. 952 */ 953 if (!list_empty(&q->retransmit)) 954 goto sctp_flush_out; 955 } 956 957 /* Apply Max.Burst limitation to the current transport in 958 * case it will be used for new data. We are going to 959 * rest it before we return, but we want to apply the limit 960 * to the currently queued data. 961 */ 962 if (transport) 963 sctp_transport_burst_limited(transport); 964 965 /* Finally, transmit new packets. */ 966 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) { 967 /* RFC 2960 6.5 Every DATA chunk MUST carry a valid 968 * stream identifier. 969 */ 970 if (chunk->sinfo.sinfo_stream >= 971 asoc->c.sinit_num_ostreams) { 972 973 /* Mark as failed send. */ 974 sctp_chunk_fail(chunk, SCTP_ERROR_INV_STRM); 975 sctp_chunk_free(chunk); 976 continue; 977 } 978 979 /* Has this chunk expired? */ 980 if (sctp_chunk_abandoned(chunk)) { 981 sctp_chunk_fail(chunk, 0); 982 sctp_chunk_free(chunk); 983 continue; 984 } 985 986 /* If there is a specified transport, use it. 987 * Otherwise, we want to use the active path. 988 */ 989 new_transport = chunk->transport; 990 if (!new_transport || 991 ((new_transport->state == SCTP_INACTIVE) || 992 (new_transport->state == SCTP_UNCONFIRMED) || 993 (new_transport->state == SCTP_PF))) 994 new_transport = asoc->peer.active_path; 995 if (new_transport->state == SCTP_UNCONFIRMED) 996 continue; 997 998 /* Change packets if necessary. */ 999 if (new_transport != transport) { 1000 transport = new_transport; 1001 1002 /* Schedule to have this transport's 1003 * packet flushed. 1004 */ 1005 if (list_empty(&transport->send_ready)) { 1006 list_add_tail(&transport->send_ready, 1007 &transport_list); 1008 } 1009 1010 packet = &transport->packet; 1011 sctp_packet_config(packet, vtag, 1012 asoc->peer.ecn_capable); 1013 /* We've switched transports, so apply the 1014 * Burst limit to the new transport. 1015 */ 1016 sctp_transport_burst_limited(transport); 1017 } 1018 1019 SCTP_DEBUG_PRINTK("sctp_outq_flush(%p, %p[%s]), ", 1020 q, chunk, 1021 chunk && chunk->chunk_hdr ? 1022 sctp_cname(SCTP_ST_CHUNK( 1023 chunk->chunk_hdr->type)) 1024 : "Illegal Chunk"); 1025 1026 SCTP_DEBUG_PRINTK("TX TSN 0x%x skb->head " 1027 "%p skb->users %d.\n", 1028 ntohl(chunk->subh.data_hdr->tsn), 1029 chunk->skb ?chunk->skb->head : NULL, 1030 chunk->skb ? 1031 atomic_read(&chunk->skb->users) : -1); 1032 1033 /* Add the chunk to the packet. */ 1034 status = sctp_packet_transmit_chunk(packet, chunk, 0); 1035 1036 switch (status) { 1037 case SCTP_XMIT_PMTU_FULL: 1038 case SCTP_XMIT_RWND_FULL: 1039 case SCTP_XMIT_NAGLE_DELAY: 1040 /* We could not append this chunk, so put 1041 * the chunk back on the output queue. 1042 */ 1043 SCTP_DEBUG_PRINTK("sctp_outq_flush: could " 1044 "not transmit TSN: 0x%x, status: %d\n", 1045 ntohl(chunk->subh.data_hdr->tsn), 1046 status); 1047 sctp_outq_head_data(q, chunk); 1048 goto sctp_flush_out; 1049 break; 1050 1051 case SCTP_XMIT_OK: 1052 /* The sender is in the SHUTDOWN-PENDING state, 1053 * The sender MAY set the I-bit in the DATA 1054 * chunk header. 1055 */ 1056 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING) 1057 chunk->chunk_hdr->flags |= SCTP_DATA_SACK_IMM; 1058 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) 1059 asoc->stats.ouodchunks++; 1060 else 1061 asoc->stats.oodchunks++; 1062 1063 break; 1064 1065 default: 1066 BUG(); 1067 } 1068 1069 /* BUG: We assume that the sctp_packet_transmit() 1070 * call below will succeed all the time and add the 1071 * chunk to the transmitted list and restart the 1072 * timers. 1073 * It is possible that the call can fail under OOM 1074 * conditions. 1075 * 1076 * Is this really a problem? Won't this behave 1077 * like a lost TSN? 1078 */ 1079 list_add_tail(&chunk->transmitted_list, 1080 &transport->transmitted); 1081 1082 sctp_transport_reset_timers(transport); 1083 1084 q->empty = 0; 1085 1086 /* Only let one DATA chunk get bundled with a 1087 * COOKIE-ECHO chunk. 1088 */ 1089 if (packet->has_cookie_echo) 1090 goto sctp_flush_out; 1091 } 1092 break; 1093 1094 default: 1095 /* Do nothing. */ 1096 break; 1097 } 1098 1099 sctp_flush_out: 1100 1101 /* Before returning, examine all the transports touched in 1102 * this call. Right now, we bluntly force clear all the 1103 * transports. Things might change after we implement Nagle. 1104 * But such an examination is still required. 1105 * 1106 * --xguo 1107 */ 1108 while ((ltransport = sctp_list_dequeue(&transport_list)) != NULL ) { 1109 struct sctp_transport *t = list_entry(ltransport, 1110 struct sctp_transport, 1111 send_ready); 1112 packet = &t->packet; 1113 if (!sctp_packet_empty(packet)) 1114 error = sctp_packet_transmit(packet); 1115 1116 /* Clear the burst limited state, if any */ 1117 sctp_transport_burst_reset(t); 1118 } 1119 1120 return error; 1121 } 1122 1123 /* Update unack_data based on the incoming SACK chunk */ 1124 static void sctp_sack_update_unack_data(struct sctp_association *assoc, 1125 struct sctp_sackhdr *sack) 1126 { 1127 sctp_sack_variable_t *frags; 1128 __u16 unack_data; 1129 int i; 1130 1131 unack_data = assoc->next_tsn - assoc->ctsn_ack_point - 1; 1132 1133 frags = sack->variable; 1134 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); i++) { 1135 unack_data -= ((ntohs(frags[i].gab.end) - 1136 ntohs(frags[i].gab.start) + 1)); 1137 } 1138 1139 assoc->unack_data = unack_data; 1140 } 1141 1142 /* This is where we REALLY process a SACK. 1143 * 1144 * Process the SACK against the outqueue. Mostly, this just frees 1145 * things off the transmitted queue. 1146 */ 1147 int sctp_outq_sack(struct sctp_outq *q, struct sctp_chunk *chunk) 1148 { 1149 struct sctp_association *asoc = q->asoc; 1150 struct sctp_sackhdr *sack = chunk->subh.sack_hdr; 1151 struct sctp_transport *transport; 1152 struct sctp_chunk *tchunk = NULL; 1153 struct list_head *lchunk, *transport_list, *temp; 1154 sctp_sack_variable_t *frags = sack->variable; 1155 __u32 sack_ctsn, ctsn, tsn; 1156 __u32 highest_tsn, highest_new_tsn; 1157 __u32 sack_a_rwnd; 1158 unsigned int outstanding; 1159 struct sctp_transport *primary = asoc->peer.primary_path; 1160 int count_of_newacks = 0; 1161 int gap_ack_blocks; 1162 u8 accum_moved = 0; 1163 1164 /* Grab the association's destination address list. */ 1165 transport_list = &asoc->peer.transport_addr_list; 1166 1167 sack_ctsn = ntohl(sack->cum_tsn_ack); 1168 gap_ack_blocks = ntohs(sack->num_gap_ack_blocks); 1169 asoc->stats.gapcnt += gap_ack_blocks; 1170 /* 1171 * SFR-CACC algorithm: 1172 * On receipt of a SACK the sender SHOULD execute the 1173 * following statements. 1174 * 1175 * 1) If the cumulative ack in the SACK passes next tsn_at_change 1176 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be 1177 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for 1178 * all destinations. 1179 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE 1180 * is set the receiver of the SACK MUST take the following actions: 1181 * 1182 * A) Initialize the cacc_saw_newack to 0 for all destination 1183 * addresses. 1184 * 1185 * Only bother if changeover_active is set. Otherwise, this is 1186 * totally suboptimal to do on every SACK. 1187 */ 1188 if (primary->cacc.changeover_active) { 1189 u8 clear_cycling = 0; 1190 1191 if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) { 1192 primary->cacc.changeover_active = 0; 1193 clear_cycling = 1; 1194 } 1195 1196 if (clear_cycling || gap_ack_blocks) { 1197 list_for_each_entry(transport, transport_list, 1198 transports) { 1199 if (clear_cycling) 1200 transport->cacc.cycling_changeover = 0; 1201 if (gap_ack_blocks) 1202 transport->cacc.cacc_saw_newack = 0; 1203 } 1204 } 1205 } 1206 1207 /* Get the highest TSN in the sack. */ 1208 highest_tsn = sack_ctsn; 1209 if (gap_ack_blocks) 1210 highest_tsn += ntohs(frags[gap_ack_blocks - 1].gab.end); 1211 1212 if (TSN_lt(asoc->highest_sacked, highest_tsn)) 1213 asoc->highest_sacked = highest_tsn; 1214 1215 highest_new_tsn = sack_ctsn; 1216 1217 /* Run through the retransmit queue. Credit bytes received 1218 * and free those chunks that we can. 1219 */ 1220 sctp_check_transmitted(q, &q->retransmit, NULL, NULL, sack, &highest_new_tsn); 1221 1222 /* Run through the transmitted queue. 1223 * Credit bytes received and free those chunks which we can. 1224 * 1225 * This is a MASSIVE candidate for optimization. 1226 */ 1227 list_for_each_entry(transport, transport_list, transports) { 1228 sctp_check_transmitted(q, &transport->transmitted, 1229 transport, &chunk->source, sack, 1230 &highest_new_tsn); 1231 /* 1232 * SFR-CACC algorithm: 1233 * C) Let count_of_newacks be the number of 1234 * destinations for which cacc_saw_newack is set. 1235 */ 1236 if (transport->cacc.cacc_saw_newack) 1237 count_of_newacks ++; 1238 } 1239 1240 /* Move the Cumulative TSN Ack Point if appropriate. */ 1241 if (TSN_lt(asoc->ctsn_ack_point, sack_ctsn)) { 1242 asoc->ctsn_ack_point = sack_ctsn; 1243 accum_moved = 1; 1244 } 1245 1246 if (gap_ack_blocks) { 1247 1248 if (asoc->fast_recovery && accum_moved) 1249 highest_new_tsn = highest_tsn; 1250 1251 list_for_each_entry(transport, transport_list, transports) 1252 sctp_mark_missing(q, &transport->transmitted, transport, 1253 highest_new_tsn, count_of_newacks); 1254 } 1255 1256 /* Update unack_data field in the assoc. */ 1257 sctp_sack_update_unack_data(asoc, sack); 1258 1259 ctsn = asoc->ctsn_ack_point; 1260 1261 /* Throw away stuff rotting on the sack queue. */ 1262 list_for_each_safe(lchunk, temp, &q->sacked) { 1263 tchunk = list_entry(lchunk, struct sctp_chunk, 1264 transmitted_list); 1265 tsn = ntohl(tchunk->subh.data_hdr->tsn); 1266 if (TSN_lte(tsn, ctsn)) { 1267 list_del_init(&tchunk->transmitted_list); 1268 sctp_chunk_free(tchunk); 1269 } 1270 } 1271 1272 /* ii) Set rwnd equal to the newly received a_rwnd minus the 1273 * number of bytes still outstanding after processing the 1274 * Cumulative TSN Ack and the Gap Ack Blocks. 1275 */ 1276 1277 sack_a_rwnd = ntohl(sack->a_rwnd); 1278 outstanding = q->outstanding_bytes; 1279 1280 if (outstanding < sack_a_rwnd) 1281 sack_a_rwnd -= outstanding; 1282 else 1283 sack_a_rwnd = 0; 1284 1285 asoc->peer.rwnd = sack_a_rwnd; 1286 1287 sctp_generate_fwdtsn(q, sack_ctsn); 1288 1289 SCTP_DEBUG_PRINTK("%s: sack Cumulative TSN Ack is 0x%x.\n", 1290 __func__, sack_ctsn); 1291 SCTP_DEBUG_PRINTK("%s: Cumulative TSN Ack of association, " 1292 "%p is 0x%x. Adv peer ack point: 0x%x\n", 1293 __func__, asoc, ctsn, asoc->adv_peer_ack_point); 1294 1295 /* See if all chunks are acked. 1296 * Make sure the empty queue handler will get run later. 1297 */ 1298 q->empty = (list_empty(&q->out_chunk_list) && 1299 list_empty(&q->retransmit)); 1300 if (!q->empty) 1301 goto finish; 1302 1303 list_for_each_entry(transport, transport_list, transports) { 1304 q->empty = q->empty && list_empty(&transport->transmitted); 1305 if (!q->empty) 1306 goto finish; 1307 } 1308 1309 SCTP_DEBUG_PRINTK("sack queue is empty.\n"); 1310 finish: 1311 return q->empty; 1312 } 1313 1314 /* Is the outqueue empty? */ 1315 int sctp_outq_is_empty(const struct sctp_outq *q) 1316 { 1317 return q->empty; 1318 } 1319 1320 /******************************************************************** 1321 * 2nd Level Abstractions 1322 ********************************************************************/ 1323 1324 /* Go through a transport's transmitted list or the association's retransmit 1325 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked. 1326 * The retransmit list will not have an associated transport. 1327 * 1328 * I added coherent debug information output. --xguo 1329 * 1330 * Instead of printing 'sacked' or 'kept' for each TSN on the 1331 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5. 1332 * KEPT TSN6-TSN7, etc. 1333 */ 1334 static void sctp_check_transmitted(struct sctp_outq *q, 1335 struct list_head *transmitted_queue, 1336 struct sctp_transport *transport, 1337 union sctp_addr *saddr, 1338 struct sctp_sackhdr *sack, 1339 __u32 *highest_new_tsn_in_sack) 1340 { 1341 struct list_head *lchunk; 1342 struct sctp_chunk *tchunk; 1343 struct list_head tlist; 1344 __u32 tsn; 1345 __u32 sack_ctsn; 1346 __u32 rtt; 1347 __u8 restart_timer = 0; 1348 int bytes_acked = 0; 1349 int migrate_bytes = 0; 1350 1351 /* These state variables are for coherent debug output. --xguo */ 1352 1353 #if SCTP_DEBUG 1354 __u32 dbg_ack_tsn = 0; /* An ACKed TSN range starts here... */ 1355 __u32 dbg_last_ack_tsn = 0; /* ...and finishes here. */ 1356 __u32 dbg_kept_tsn = 0; /* An un-ACKed range starts here... */ 1357 __u32 dbg_last_kept_tsn = 0; /* ...and finishes here. */ 1358 1359 /* 0 : The last TSN was ACKed. 1360 * 1 : The last TSN was NOT ACKed (i.e. KEPT). 1361 * -1: We need to initialize. 1362 */ 1363 int dbg_prt_state = -1; 1364 #endif /* SCTP_DEBUG */ 1365 1366 sack_ctsn = ntohl(sack->cum_tsn_ack); 1367 1368 INIT_LIST_HEAD(&tlist); 1369 1370 /* The while loop will skip empty transmitted queues. */ 1371 while (NULL != (lchunk = sctp_list_dequeue(transmitted_queue))) { 1372 tchunk = list_entry(lchunk, struct sctp_chunk, 1373 transmitted_list); 1374 1375 if (sctp_chunk_abandoned(tchunk)) { 1376 /* Move the chunk to abandoned list. */ 1377 sctp_insert_list(&q->abandoned, lchunk); 1378 1379 /* If this chunk has not been acked, stop 1380 * considering it as 'outstanding'. 1381 */ 1382 if (!tchunk->tsn_gap_acked) { 1383 if (tchunk->transport) 1384 tchunk->transport->flight_size -= 1385 sctp_data_size(tchunk); 1386 q->outstanding_bytes -= sctp_data_size(tchunk); 1387 } 1388 continue; 1389 } 1390 1391 tsn = ntohl(tchunk->subh.data_hdr->tsn); 1392 if (sctp_acked(sack, tsn)) { 1393 /* If this queue is the retransmit queue, the 1394 * retransmit timer has already reclaimed 1395 * the outstanding bytes for this chunk, so only 1396 * count bytes associated with a transport. 1397 */ 1398 if (transport) { 1399 /* If this chunk is being used for RTT 1400 * measurement, calculate the RTT and update 1401 * the RTO using this value. 1402 * 1403 * 6.3.1 C5) Karn's algorithm: RTT measurements 1404 * MUST NOT be made using packets that were 1405 * retransmitted (and thus for which it is 1406 * ambiguous whether the reply was for the 1407 * first instance of the packet or a later 1408 * instance). 1409 */ 1410 if (!tchunk->tsn_gap_acked && 1411 tchunk->rtt_in_progress) { 1412 tchunk->rtt_in_progress = 0; 1413 rtt = jiffies - tchunk->sent_at; 1414 sctp_transport_update_rto(transport, 1415 rtt); 1416 } 1417 } 1418 1419 /* If the chunk hasn't been marked as ACKED, 1420 * mark it and account bytes_acked if the 1421 * chunk had a valid transport (it will not 1422 * have a transport if ASCONF had deleted it 1423 * while DATA was outstanding). 1424 */ 1425 if (!tchunk->tsn_gap_acked) { 1426 tchunk->tsn_gap_acked = 1; 1427 *highest_new_tsn_in_sack = tsn; 1428 bytes_acked += sctp_data_size(tchunk); 1429 if (!tchunk->transport) 1430 migrate_bytes += sctp_data_size(tchunk); 1431 } 1432 1433 if (TSN_lte(tsn, sack_ctsn)) { 1434 /* RFC 2960 6.3.2 Retransmission Timer Rules 1435 * 1436 * R3) Whenever a SACK is received 1437 * that acknowledges the DATA chunk 1438 * with the earliest outstanding TSN 1439 * for that address, restart T3-rtx 1440 * timer for that address with its 1441 * current RTO. 1442 */ 1443 restart_timer = 1; 1444 1445 if (!tchunk->tsn_gap_acked) { 1446 /* 1447 * SFR-CACC algorithm: 1448 * 2) If the SACK contains gap acks 1449 * and the flag CHANGEOVER_ACTIVE is 1450 * set the receiver of the SACK MUST 1451 * take the following action: 1452 * 1453 * B) For each TSN t being acked that 1454 * has not been acked in any SACK so 1455 * far, set cacc_saw_newack to 1 for 1456 * the destination that the TSN was 1457 * sent to. 1458 */ 1459 if (transport && 1460 sack->num_gap_ack_blocks && 1461 q->asoc->peer.primary_path->cacc. 1462 changeover_active) 1463 transport->cacc.cacc_saw_newack 1464 = 1; 1465 } 1466 1467 list_add_tail(&tchunk->transmitted_list, 1468 &q->sacked); 1469 } else { 1470 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2 1471 * M2) Each time a SACK arrives reporting 1472 * 'Stray DATA chunk(s)' record the highest TSN 1473 * reported as newly acknowledged, call this 1474 * value 'HighestTSNinSack'. A newly 1475 * acknowledged DATA chunk is one not 1476 * previously acknowledged in a SACK. 1477 * 1478 * When the SCTP sender of data receives a SACK 1479 * chunk that acknowledges, for the first time, 1480 * the receipt of a DATA chunk, all the still 1481 * unacknowledged DATA chunks whose TSN is 1482 * older than that newly acknowledged DATA 1483 * chunk, are qualified as 'Stray DATA chunks'. 1484 */ 1485 list_add_tail(lchunk, &tlist); 1486 } 1487 1488 #if SCTP_DEBUG 1489 switch (dbg_prt_state) { 1490 case 0: /* last TSN was ACKed */ 1491 if (dbg_last_ack_tsn + 1 == tsn) { 1492 /* This TSN belongs to the 1493 * current ACK range. 1494 */ 1495 break; 1496 } 1497 1498 if (dbg_last_ack_tsn != dbg_ack_tsn) { 1499 /* Display the end of the 1500 * current range. 1501 */ 1502 SCTP_DEBUG_PRINTK_CONT("-%08x", 1503 dbg_last_ack_tsn); 1504 } 1505 1506 /* Start a new range. */ 1507 SCTP_DEBUG_PRINTK_CONT(",%08x", tsn); 1508 dbg_ack_tsn = tsn; 1509 break; 1510 1511 case 1: /* The last TSN was NOT ACKed. */ 1512 if (dbg_last_kept_tsn != dbg_kept_tsn) { 1513 /* Display the end of current range. */ 1514 SCTP_DEBUG_PRINTK_CONT("-%08x", 1515 dbg_last_kept_tsn); 1516 } 1517 1518 SCTP_DEBUG_PRINTK_CONT("\n"); 1519 1520 /* FALL THROUGH... */ 1521 default: 1522 /* This is the first-ever TSN we examined. */ 1523 /* Start a new range of ACK-ed TSNs. */ 1524 SCTP_DEBUG_PRINTK("ACKed: %08x", tsn); 1525 dbg_prt_state = 0; 1526 dbg_ack_tsn = tsn; 1527 } 1528 1529 dbg_last_ack_tsn = tsn; 1530 #endif /* SCTP_DEBUG */ 1531 1532 } else { 1533 if (tchunk->tsn_gap_acked) { 1534 SCTP_DEBUG_PRINTK("%s: Receiver reneged on " 1535 "data TSN: 0x%x\n", 1536 __func__, 1537 tsn); 1538 tchunk->tsn_gap_acked = 0; 1539 1540 if (tchunk->transport) 1541 bytes_acked -= sctp_data_size(tchunk); 1542 1543 /* RFC 2960 6.3.2 Retransmission Timer Rules 1544 * 1545 * R4) Whenever a SACK is received missing a 1546 * TSN that was previously acknowledged via a 1547 * Gap Ack Block, start T3-rtx for the 1548 * destination address to which the DATA 1549 * chunk was originally 1550 * transmitted if it is not already running. 1551 */ 1552 restart_timer = 1; 1553 } 1554 1555 list_add_tail(lchunk, &tlist); 1556 1557 #if SCTP_DEBUG 1558 /* See the above comments on ACK-ed TSNs. */ 1559 switch (dbg_prt_state) { 1560 case 1: 1561 if (dbg_last_kept_tsn + 1 == tsn) 1562 break; 1563 1564 if (dbg_last_kept_tsn != dbg_kept_tsn) 1565 SCTP_DEBUG_PRINTK_CONT("-%08x", 1566 dbg_last_kept_tsn); 1567 1568 SCTP_DEBUG_PRINTK_CONT(",%08x", tsn); 1569 dbg_kept_tsn = tsn; 1570 break; 1571 1572 case 0: 1573 if (dbg_last_ack_tsn != dbg_ack_tsn) 1574 SCTP_DEBUG_PRINTK_CONT("-%08x", 1575 dbg_last_ack_tsn); 1576 SCTP_DEBUG_PRINTK_CONT("\n"); 1577 1578 /* FALL THROUGH... */ 1579 default: 1580 SCTP_DEBUG_PRINTK("KEPT: %08x",tsn); 1581 dbg_prt_state = 1; 1582 dbg_kept_tsn = tsn; 1583 } 1584 1585 dbg_last_kept_tsn = tsn; 1586 #endif /* SCTP_DEBUG */ 1587 } 1588 } 1589 1590 #if SCTP_DEBUG 1591 /* Finish off the last range, displaying its ending TSN. */ 1592 switch (dbg_prt_state) { 1593 case 0: 1594 if (dbg_last_ack_tsn != dbg_ack_tsn) { 1595 SCTP_DEBUG_PRINTK_CONT("-%08x\n", dbg_last_ack_tsn); 1596 } else { 1597 SCTP_DEBUG_PRINTK_CONT("\n"); 1598 } 1599 break; 1600 1601 case 1: 1602 if (dbg_last_kept_tsn != dbg_kept_tsn) { 1603 SCTP_DEBUG_PRINTK_CONT("-%08x\n", dbg_last_kept_tsn); 1604 } else { 1605 SCTP_DEBUG_PRINTK_CONT("\n"); 1606 } 1607 } 1608 #endif /* SCTP_DEBUG */ 1609 if (transport) { 1610 if (bytes_acked) { 1611 struct sctp_association *asoc = transport->asoc; 1612 1613 /* We may have counted DATA that was migrated 1614 * to this transport due to DEL-IP operation. 1615 * Subtract those bytes, since the were never 1616 * send on this transport and shouldn't be 1617 * credited to this transport. 1618 */ 1619 bytes_acked -= migrate_bytes; 1620 1621 /* 8.2. When an outstanding TSN is acknowledged, 1622 * the endpoint shall clear the error counter of 1623 * the destination transport address to which the 1624 * DATA chunk was last sent. 1625 * The association's overall error counter is 1626 * also cleared. 1627 */ 1628 transport->error_count = 0; 1629 transport->asoc->overall_error_count = 0; 1630 1631 /* 1632 * While in SHUTDOWN PENDING, we may have started 1633 * the T5 shutdown guard timer after reaching the 1634 * retransmission limit. Stop that timer as soon 1635 * as the receiver acknowledged any data. 1636 */ 1637 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING && 1638 del_timer(&asoc->timers 1639 [SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD])) 1640 sctp_association_put(asoc); 1641 1642 /* Mark the destination transport address as 1643 * active if it is not so marked. 1644 */ 1645 if ((transport->state == SCTP_INACTIVE || 1646 transport->state == SCTP_UNCONFIRMED) && 1647 sctp_cmp_addr_exact(&transport->ipaddr, saddr)) { 1648 sctp_assoc_control_transport( 1649 transport->asoc, 1650 transport, 1651 SCTP_TRANSPORT_UP, 1652 SCTP_RECEIVED_SACK); 1653 } 1654 1655 sctp_transport_raise_cwnd(transport, sack_ctsn, 1656 bytes_acked); 1657 1658 transport->flight_size -= bytes_acked; 1659 if (transport->flight_size == 0) 1660 transport->partial_bytes_acked = 0; 1661 q->outstanding_bytes -= bytes_acked + migrate_bytes; 1662 } else { 1663 /* RFC 2960 6.1, sctpimpguide-06 2.15.2 1664 * When a sender is doing zero window probing, it 1665 * should not timeout the association if it continues 1666 * to receive new packets from the receiver. The 1667 * reason is that the receiver MAY keep its window 1668 * closed for an indefinite time. 1669 * A sender is doing zero window probing when the 1670 * receiver's advertised window is zero, and there is 1671 * only one data chunk in flight to the receiver. 1672 * 1673 * Allow the association to timeout while in SHUTDOWN 1674 * PENDING or SHUTDOWN RECEIVED in case the receiver 1675 * stays in zero window mode forever. 1676 */ 1677 if (!q->asoc->peer.rwnd && 1678 !list_empty(&tlist) && 1679 (sack_ctsn+2 == q->asoc->next_tsn) && 1680 q->asoc->state < SCTP_STATE_SHUTDOWN_PENDING) { 1681 SCTP_DEBUG_PRINTK("%s: SACK received for zero " 1682 "window probe: %u\n", 1683 __func__, sack_ctsn); 1684 q->asoc->overall_error_count = 0; 1685 transport->error_count = 0; 1686 } 1687 } 1688 1689 /* RFC 2960 6.3.2 Retransmission Timer Rules 1690 * 1691 * R2) Whenever all outstanding data sent to an address have 1692 * been acknowledged, turn off the T3-rtx timer of that 1693 * address. 1694 */ 1695 if (!transport->flight_size) { 1696 if (del_timer(&transport->T3_rtx_timer)) 1697 sctp_transport_put(transport); 1698 } else if (restart_timer) { 1699 if (!mod_timer(&transport->T3_rtx_timer, 1700 jiffies + transport->rto)) 1701 sctp_transport_hold(transport); 1702 } 1703 } 1704 1705 list_splice(&tlist, transmitted_queue); 1706 } 1707 1708 /* Mark chunks as missing and consequently may get retransmitted. */ 1709 static void sctp_mark_missing(struct sctp_outq *q, 1710 struct list_head *transmitted_queue, 1711 struct sctp_transport *transport, 1712 __u32 highest_new_tsn_in_sack, 1713 int count_of_newacks) 1714 { 1715 struct sctp_chunk *chunk; 1716 __u32 tsn; 1717 char do_fast_retransmit = 0; 1718 struct sctp_association *asoc = q->asoc; 1719 struct sctp_transport *primary = asoc->peer.primary_path; 1720 1721 list_for_each_entry(chunk, transmitted_queue, transmitted_list) { 1722 1723 tsn = ntohl(chunk->subh.data_hdr->tsn); 1724 1725 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all 1726 * 'Unacknowledged TSN's', if the TSN number of an 1727 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack' 1728 * value, increment the 'TSN.Missing.Report' count on that 1729 * chunk if it has NOT been fast retransmitted or marked for 1730 * fast retransmit already. 1731 */ 1732 if (chunk->fast_retransmit == SCTP_CAN_FRTX && 1733 !chunk->tsn_gap_acked && 1734 TSN_lt(tsn, highest_new_tsn_in_sack)) { 1735 1736 /* SFR-CACC may require us to skip marking 1737 * this chunk as missing. 1738 */ 1739 if (!transport || !sctp_cacc_skip(primary, 1740 chunk->transport, 1741 count_of_newacks, tsn)) { 1742 chunk->tsn_missing_report++; 1743 1744 SCTP_DEBUG_PRINTK( 1745 "%s: TSN 0x%x missing counter: %d\n", 1746 __func__, tsn, 1747 chunk->tsn_missing_report); 1748 } 1749 } 1750 /* 1751 * M4) If any DATA chunk is found to have a 1752 * 'TSN.Missing.Report' 1753 * value larger than or equal to 3, mark that chunk for 1754 * retransmission and start the fast retransmit procedure. 1755 */ 1756 1757 if (chunk->tsn_missing_report >= 3) { 1758 chunk->fast_retransmit = SCTP_NEED_FRTX; 1759 do_fast_retransmit = 1; 1760 } 1761 } 1762 1763 if (transport) { 1764 if (do_fast_retransmit) 1765 sctp_retransmit(q, transport, SCTP_RTXR_FAST_RTX); 1766 1767 SCTP_DEBUG_PRINTK("%s: transport: %p, cwnd: %d, " 1768 "ssthresh: %d, flight_size: %d, pba: %d\n", 1769 __func__, transport, transport->cwnd, 1770 transport->ssthresh, transport->flight_size, 1771 transport->partial_bytes_acked); 1772 } 1773 } 1774 1775 /* Is the given TSN acked by this packet? */ 1776 static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn) 1777 { 1778 int i; 1779 sctp_sack_variable_t *frags; 1780 __u16 gap; 1781 __u32 ctsn = ntohl(sack->cum_tsn_ack); 1782 1783 if (TSN_lte(tsn, ctsn)) 1784 goto pass; 1785 1786 /* 3.3.4 Selective Acknowledgement (SACK) (3): 1787 * 1788 * Gap Ack Blocks: 1789 * These fields contain the Gap Ack Blocks. They are repeated 1790 * for each Gap Ack Block up to the number of Gap Ack Blocks 1791 * defined in the Number of Gap Ack Blocks field. All DATA 1792 * chunks with TSNs greater than or equal to (Cumulative TSN 1793 * Ack + Gap Ack Block Start) and less than or equal to 1794 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack 1795 * Block are assumed to have been received correctly. 1796 */ 1797 1798 frags = sack->variable; 1799 gap = tsn - ctsn; 1800 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); ++i) { 1801 if (TSN_lte(ntohs(frags[i].gab.start), gap) && 1802 TSN_lte(gap, ntohs(frags[i].gab.end))) 1803 goto pass; 1804 } 1805 1806 return 0; 1807 pass: 1808 return 1; 1809 } 1810 1811 static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip *skiplist, 1812 int nskips, __be16 stream) 1813 { 1814 int i; 1815 1816 for (i = 0; i < nskips; i++) { 1817 if (skiplist[i].stream == stream) 1818 return i; 1819 } 1820 return i; 1821 } 1822 1823 /* Create and add a fwdtsn chunk to the outq's control queue if needed. */ 1824 static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 ctsn) 1825 { 1826 struct sctp_association *asoc = q->asoc; 1827 struct sctp_chunk *ftsn_chunk = NULL; 1828 struct sctp_fwdtsn_skip ftsn_skip_arr[10]; 1829 int nskips = 0; 1830 int skip_pos = 0; 1831 __u32 tsn; 1832 struct sctp_chunk *chunk; 1833 struct list_head *lchunk, *temp; 1834 1835 if (!asoc->peer.prsctp_capable) 1836 return; 1837 1838 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the 1839 * received SACK. 1840 * 1841 * If (Advanced.Peer.Ack.Point < SackCumAck), then update 1842 * Advanced.Peer.Ack.Point to be equal to SackCumAck. 1843 */ 1844 if (TSN_lt(asoc->adv_peer_ack_point, ctsn)) 1845 asoc->adv_peer_ack_point = ctsn; 1846 1847 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point" 1848 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as 1849 * the chunk next in the out-queue space is marked as "abandoned" as 1850 * shown in the following example: 1851 * 1852 * Assuming that a SACK arrived with the Cumulative TSN ACK 102 1853 * and the Advanced.Peer.Ack.Point is updated to this value: 1854 * 1855 * out-queue at the end of ==> out-queue after Adv.Ack.Point 1856 * normal SACK processing local advancement 1857 * ... ... 1858 * Adv.Ack.Pt-> 102 acked 102 acked 1859 * 103 abandoned 103 abandoned 1860 * 104 abandoned Adv.Ack.P-> 104 abandoned 1861 * 105 105 1862 * 106 acked 106 acked 1863 * ... ... 1864 * 1865 * In this example, the data sender successfully advanced the 1866 * "Advanced.Peer.Ack.Point" from 102 to 104 locally. 1867 */ 1868 list_for_each_safe(lchunk, temp, &q->abandoned) { 1869 chunk = list_entry(lchunk, struct sctp_chunk, 1870 transmitted_list); 1871 tsn = ntohl(chunk->subh.data_hdr->tsn); 1872 1873 /* Remove any chunks in the abandoned queue that are acked by 1874 * the ctsn. 1875 */ 1876 if (TSN_lte(tsn, ctsn)) { 1877 list_del_init(lchunk); 1878 sctp_chunk_free(chunk); 1879 } else { 1880 if (TSN_lte(tsn, asoc->adv_peer_ack_point+1)) { 1881 asoc->adv_peer_ack_point = tsn; 1882 if (chunk->chunk_hdr->flags & 1883 SCTP_DATA_UNORDERED) 1884 continue; 1885 skip_pos = sctp_get_skip_pos(&ftsn_skip_arr[0], 1886 nskips, 1887 chunk->subh.data_hdr->stream); 1888 ftsn_skip_arr[skip_pos].stream = 1889 chunk->subh.data_hdr->stream; 1890 ftsn_skip_arr[skip_pos].ssn = 1891 chunk->subh.data_hdr->ssn; 1892 if (skip_pos == nskips) 1893 nskips++; 1894 if (nskips == 10) 1895 break; 1896 } else 1897 break; 1898 } 1899 } 1900 1901 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point" 1902 * is greater than the Cumulative TSN ACK carried in the received 1903 * SACK, the data sender MUST send the data receiver a FORWARD TSN 1904 * chunk containing the latest value of the 1905 * "Advanced.Peer.Ack.Point". 1906 * 1907 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD 1908 * list each stream and sequence number in the forwarded TSN. This 1909 * information will enable the receiver to easily find any 1910 * stranded TSN's waiting on stream reorder queues. Each stream 1911 * SHOULD only be reported once; this means that if multiple 1912 * abandoned messages occur in the same stream then only the 1913 * highest abandoned stream sequence number is reported. If the 1914 * total size of the FORWARD TSN does NOT fit in a single MTU then 1915 * the sender of the FORWARD TSN SHOULD lower the 1916 * Advanced.Peer.Ack.Point to the last TSN that will fit in a 1917 * single MTU. 1918 */ 1919 if (asoc->adv_peer_ack_point > ctsn) 1920 ftsn_chunk = sctp_make_fwdtsn(asoc, asoc->adv_peer_ack_point, 1921 nskips, &ftsn_skip_arr[0]); 1922 1923 if (ftsn_chunk) { 1924 list_add_tail(&ftsn_chunk->list, &q->control_chunk_list); 1925 SCTP_INC_STATS(sock_net(asoc->base.sk), SCTP_MIB_OUTCTRLCHUNKS); 1926 } 1927 } 1928