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 memset(q, 0, sizeof(struct sctp_outq)); 210 211 q->asoc = asoc; 212 INIT_LIST_HEAD(&q->out_chunk_list); 213 INIT_LIST_HEAD(&q->control_chunk_list); 214 INIT_LIST_HEAD(&q->retransmit); 215 INIT_LIST_HEAD(&q->sacked); 216 INIT_LIST_HEAD(&q->abandoned); 217 218 q->empty = 1; 219 } 220 221 /* Free the outqueue structure and any related pending chunks. 222 */ 223 static void __sctp_outq_teardown(struct sctp_outq *q) 224 { 225 struct sctp_transport *transport; 226 struct list_head *lchunk, *temp; 227 struct sctp_chunk *chunk, *tmp; 228 229 /* Throw away unacknowledged chunks. */ 230 list_for_each_entry(transport, &q->asoc->peer.transport_addr_list, 231 transports) { 232 while ((lchunk = sctp_list_dequeue(&transport->transmitted)) != NULL) { 233 chunk = list_entry(lchunk, struct sctp_chunk, 234 transmitted_list); 235 /* Mark as part of a failed message. */ 236 sctp_chunk_fail(chunk, q->error); 237 sctp_chunk_free(chunk); 238 } 239 } 240 241 /* Throw away chunks that have been gap ACKed. */ 242 list_for_each_safe(lchunk, temp, &q->sacked) { 243 list_del_init(lchunk); 244 chunk = list_entry(lchunk, struct sctp_chunk, 245 transmitted_list); 246 sctp_chunk_fail(chunk, q->error); 247 sctp_chunk_free(chunk); 248 } 249 250 /* Throw away any chunks in the retransmit queue. */ 251 list_for_each_safe(lchunk, temp, &q->retransmit) { 252 list_del_init(lchunk); 253 chunk = list_entry(lchunk, struct sctp_chunk, 254 transmitted_list); 255 sctp_chunk_fail(chunk, q->error); 256 sctp_chunk_free(chunk); 257 } 258 259 /* Throw away any chunks that are in the abandoned queue. */ 260 list_for_each_safe(lchunk, temp, &q->abandoned) { 261 list_del_init(lchunk); 262 chunk = list_entry(lchunk, struct sctp_chunk, 263 transmitted_list); 264 sctp_chunk_fail(chunk, q->error); 265 sctp_chunk_free(chunk); 266 } 267 268 /* Throw away any leftover data chunks. */ 269 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) { 270 271 /* Mark as send failure. */ 272 sctp_chunk_fail(chunk, q->error); 273 sctp_chunk_free(chunk); 274 } 275 276 /* Throw away any leftover control chunks. */ 277 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) { 278 list_del_init(&chunk->list); 279 sctp_chunk_free(chunk); 280 } 281 } 282 283 void sctp_outq_teardown(struct sctp_outq *q) 284 { 285 __sctp_outq_teardown(q); 286 sctp_outq_init(q->asoc, q); 287 } 288 289 /* Free the outqueue structure and any related pending chunks. */ 290 void sctp_outq_free(struct sctp_outq *q) 291 { 292 /* Throw away leftover chunks. */ 293 __sctp_outq_teardown(q); 294 } 295 296 /* Put a new chunk in an sctp_outq. */ 297 int sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk) 298 { 299 struct net *net = sock_net(q->asoc->base.sk); 300 int error = 0; 301 302 pr_debug("%s: outq:%p, chunk:%p[%s]\n", __func__, q, chunk, 303 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_chunk_is_data(chunk)) { 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_CLOSED: 322 case SCTP_STATE_SHUTDOWN_PENDING: 323 case SCTP_STATE_SHUTDOWN_SENT: 324 case SCTP_STATE_SHUTDOWN_RECEIVED: 325 case SCTP_STATE_SHUTDOWN_ACK_SENT: 326 /* Cannot send after transport endpoint shutdown */ 327 error = -ESHUTDOWN; 328 break; 329 330 default: 331 pr_debug("%s: outqueueing: outq:%p, chunk:%p[%s])\n", 332 __func__, q, chunk, chunk && chunk->chunk_hdr ? 333 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) : 334 "illegal chunk"); 335 336 sctp_outq_tail_data(q, chunk); 337 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) 338 SCTP_INC_STATS(net, SCTP_MIB_OUTUNORDERCHUNKS); 339 else 340 SCTP_INC_STATS(net, SCTP_MIB_OUTORDERCHUNKS); 341 q->empty = 0; 342 break; 343 } 344 } else { 345 list_add_tail(&chunk->list, &q->control_chunk_list); 346 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 347 } 348 349 if (error < 0) 350 return error; 351 352 if (!q->cork) 353 error = sctp_outq_flush(q, 0); 354 355 return error; 356 } 357 358 /* Insert a chunk into the sorted list based on the TSNs. The retransmit list 359 * and the abandoned list are in ascending order. 360 */ 361 static void sctp_insert_list(struct list_head *head, struct list_head *new) 362 { 363 struct list_head *pos; 364 struct sctp_chunk *nchunk, *lchunk; 365 __u32 ntsn, ltsn; 366 int done = 0; 367 368 nchunk = list_entry(new, struct sctp_chunk, transmitted_list); 369 ntsn = ntohl(nchunk->subh.data_hdr->tsn); 370 371 list_for_each(pos, head) { 372 lchunk = list_entry(pos, struct sctp_chunk, transmitted_list); 373 ltsn = ntohl(lchunk->subh.data_hdr->tsn); 374 if (TSN_lt(ntsn, ltsn)) { 375 list_add(new, pos->prev); 376 done = 1; 377 break; 378 } 379 } 380 if (!done) 381 list_add_tail(new, head); 382 } 383 384 /* Mark all the eligible packets on a transport for retransmission. */ 385 void sctp_retransmit_mark(struct sctp_outq *q, 386 struct sctp_transport *transport, 387 __u8 reason) 388 { 389 struct list_head *lchunk, *ltemp; 390 struct sctp_chunk *chunk; 391 392 /* Walk through the specified transmitted queue. */ 393 list_for_each_safe(lchunk, ltemp, &transport->transmitted) { 394 chunk = list_entry(lchunk, struct sctp_chunk, 395 transmitted_list); 396 397 /* If the chunk is abandoned, move it to abandoned list. */ 398 if (sctp_chunk_abandoned(chunk)) { 399 list_del_init(lchunk); 400 sctp_insert_list(&q->abandoned, lchunk); 401 402 /* If this chunk has not been previousely acked, 403 * stop considering it 'outstanding'. Our peer 404 * will most likely never see it since it will 405 * not be retransmitted 406 */ 407 if (!chunk->tsn_gap_acked) { 408 if (chunk->transport) 409 chunk->transport->flight_size -= 410 sctp_data_size(chunk); 411 q->outstanding_bytes -= sctp_data_size(chunk); 412 q->asoc->peer.rwnd += sctp_data_size(chunk); 413 } 414 continue; 415 } 416 417 /* If we are doing retransmission due to a timeout or pmtu 418 * discovery, only the chunks that are not yet acked should 419 * be added to the retransmit queue. 420 */ 421 if ((reason == SCTP_RTXR_FAST_RTX && 422 (chunk->fast_retransmit == SCTP_NEED_FRTX)) || 423 (reason != SCTP_RTXR_FAST_RTX && !chunk->tsn_gap_acked)) { 424 /* RFC 2960 6.2.1 Processing a Received SACK 425 * 426 * C) Any time a DATA chunk is marked for 427 * retransmission (via either T3-rtx timer expiration 428 * (Section 6.3.3) or via fast retransmit 429 * (Section 7.2.4)), add the data size of those 430 * chunks to the rwnd. 431 */ 432 q->asoc->peer.rwnd += sctp_data_size(chunk); 433 q->outstanding_bytes -= sctp_data_size(chunk); 434 if (chunk->transport) 435 transport->flight_size -= sctp_data_size(chunk); 436 437 /* sctpimpguide-05 Section 2.8.2 438 * M5) If a T3-rtx timer expires, the 439 * 'TSN.Missing.Report' of all affected TSNs is set 440 * to 0. 441 */ 442 chunk->tsn_missing_report = 0; 443 444 /* If a chunk that is being used for RTT measurement 445 * has to be retransmitted, we cannot use this chunk 446 * anymore for RTT measurements. Reset rto_pending so 447 * that a new RTT measurement is started when a new 448 * data chunk is sent. 449 */ 450 if (chunk->rtt_in_progress) { 451 chunk->rtt_in_progress = 0; 452 transport->rto_pending = 0; 453 } 454 455 /* Move the chunk to the retransmit queue. The chunks 456 * on the retransmit queue are always kept in order. 457 */ 458 list_del_init(lchunk); 459 sctp_insert_list(&q->retransmit, lchunk); 460 } 461 } 462 463 pr_debug("%s: transport:%p, reason:%d, cwnd:%d, ssthresh:%d, " 464 "flight_size:%d, pba:%d\n", __func__, transport, reason, 465 transport->cwnd, transport->ssthresh, transport->flight_size, 466 transport->partial_bytes_acked); 467 } 468 469 /* Mark all the eligible packets on a transport for retransmission and force 470 * one packet out. 471 */ 472 void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport, 473 sctp_retransmit_reason_t reason) 474 { 475 struct net *net = sock_net(q->asoc->base.sk); 476 int error = 0; 477 478 switch(reason) { 479 case SCTP_RTXR_T3_RTX: 480 SCTP_INC_STATS(net, SCTP_MIB_T3_RETRANSMITS); 481 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_T3_RTX); 482 /* Update the retran path if the T3-rtx timer has expired for 483 * the current retran path. 484 */ 485 if (transport == transport->asoc->peer.retran_path) 486 sctp_assoc_update_retran_path(transport->asoc); 487 transport->asoc->rtx_data_chunks += 488 transport->asoc->unack_data; 489 break; 490 case SCTP_RTXR_FAST_RTX: 491 SCTP_INC_STATS(net, SCTP_MIB_FAST_RETRANSMITS); 492 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_FAST_RTX); 493 q->fast_rtx = 1; 494 break; 495 case SCTP_RTXR_PMTUD: 496 SCTP_INC_STATS(net, SCTP_MIB_PMTUD_RETRANSMITS); 497 break; 498 case SCTP_RTXR_T1_RTX: 499 SCTP_INC_STATS(net, SCTP_MIB_T1_RETRANSMITS); 500 transport->asoc->init_retries++; 501 break; 502 default: 503 BUG(); 504 } 505 506 sctp_retransmit_mark(q, transport, reason); 507 508 /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination, 509 * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by 510 * following the procedures outlined in C1 - C5. 511 */ 512 if (reason == SCTP_RTXR_T3_RTX) 513 sctp_generate_fwdtsn(q, q->asoc->ctsn_ack_point); 514 515 /* Flush the queues only on timeout, since fast_rtx is only 516 * triggered during sack processing and the queue 517 * will be flushed at the end. 518 */ 519 if (reason != SCTP_RTXR_FAST_RTX) 520 error = sctp_outq_flush(q, /* rtx_timeout */ 1); 521 522 if (error) 523 q->asoc->base.sk->sk_err = -error; 524 } 525 526 /* 527 * Transmit DATA chunks on the retransmit queue. Upon return from 528 * sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which 529 * need to be transmitted by the caller. 530 * We assume that pkt->transport has already been set. 531 * 532 * The return value is a normal kernel error return value. 533 */ 534 static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt, 535 int rtx_timeout, int *start_timer) 536 { 537 struct list_head *lqueue; 538 struct sctp_transport *transport = pkt->transport; 539 sctp_xmit_t status; 540 struct sctp_chunk *chunk, *chunk1; 541 int fast_rtx; 542 int error = 0; 543 int timer = 0; 544 int done = 0; 545 546 lqueue = &q->retransmit; 547 fast_rtx = q->fast_rtx; 548 549 /* This loop handles time-out retransmissions, fast retransmissions, 550 * and retransmissions due to opening of whindow. 551 * 552 * RFC 2960 6.3.3 Handle T3-rtx Expiration 553 * 554 * E3) Determine how many of the earliest (i.e., lowest TSN) 555 * outstanding DATA chunks for the address for which the 556 * T3-rtx has expired will fit into a single packet, subject 557 * to the MTU constraint for the path corresponding to the 558 * destination transport address to which the retransmission 559 * is being sent (this may be different from the address for 560 * which the timer expires [see Section 6.4]). Call this value 561 * K. Bundle and retransmit those K DATA chunks in a single 562 * packet to the destination endpoint. 563 * 564 * [Just to be painfully clear, if we are retransmitting 565 * because a timeout just happened, we should send only ONE 566 * packet of retransmitted data.] 567 * 568 * For fast retransmissions we also send only ONE packet. However, 569 * if we are just flushing the queue due to open window, we'll 570 * try to send as much as possible. 571 */ 572 list_for_each_entry_safe(chunk, chunk1, lqueue, transmitted_list) { 573 /* If the chunk is abandoned, move it to abandoned list. */ 574 if (sctp_chunk_abandoned(chunk)) { 575 list_del_init(&chunk->transmitted_list); 576 sctp_insert_list(&q->abandoned, 577 &chunk->transmitted_list); 578 continue; 579 } 580 581 /* Make sure that Gap Acked TSNs are not retransmitted. A 582 * simple approach is just to move such TSNs out of the 583 * way and into a 'transmitted' queue and skip to the 584 * next chunk. 585 */ 586 if (chunk->tsn_gap_acked) { 587 list_move_tail(&chunk->transmitted_list, 588 &transport->transmitted); 589 continue; 590 } 591 592 /* If we are doing fast retransmit, ignore non-fast_rtransmit 593 * chunks 594 */ 595 if (fast_rtx && !chunk->fast_retransmit) 596 continue; 597 598 redo: 599 /* Attempt to append this chunk to the packet. */ 600 status = sctp_packet_append_chunk(pkt, chunk); 601 602 switch (status) { 603 case SCTP_XMIT_PMTU_FULL: 604 if (!pkt->has_data && !pkt->has_cookie_echo) { 605 /* If this packet did not contain DATA then 606 * retransmission did not happen, so do it 607 * again. We'll ignore the error here since 608 * control chunks are already freed so there 609 * is nothing we can do. 610 */ 611 sctp_packet_transmit(pkt); 612 goto redo; 613 } 614 615 /* Send this packet. */ 616 error = sctp_packet_transmit(pkt); 617 618 /* If we are retransmitting, we should only 619 * send a single packet. 620 * Otherwise, try appending this chunk again. 621 */ 622 if (rtx_timeout || fast_rtx) 623 done = 1; 624 else 625 goto redo; 626 627 /* Bundle next chunk in the next round. */ 628 break; 629 630 case SCTP_XMIT_RWND_FULL: 631 /* Send this packet. */ 632 error = sctp_packet_transmit(pkt); 633 634 /* Stop sending DATA as there is no more room 635 * at the receiver. 636 */ 637 done = 1; 638 break; 639 640 case SCTP_XMIT_NAGLE_DELAY: 641 /* Send this packet. */ 642 error = sctp_packet_transmit(pkt); 643 644 /* Stop sending DATA because of nagle delay. */ 645 done = 1; 646 break; 647 648 default: 649 /* The append was successful, so add this chunk to 650 * the transmitted list. 651 */ 652 list_move_tail(&chunk->transmitted_list, 653 &transport->transmitted); 654 655 /* Mark the chunk as ineligible for fast retransmit 656 * after it is retransmitted. 657 */ 658 if (chunk->fast_retransmit == SCTP_NEED_FRTX) 659 chunk->fast_retransmit = SCTP_DONT_FRTX; 660 661 q->empty = 0; 662 q->asoc->stats.rtxchunks++; 663 break; 664 } 665 666 /* Set the timer if there were no errors */ 667 if (!error && !timer) 668 timer = 1; 669 670 if (done) 671 break; 672 } 673 674 /* If we are here due to a retransmit timeout or a fast 675 * retransmit and if there are any chunks left in the retransmit 676 * queue that could not fit in the PMTU sized packet, they need 677 * to be marked as ineligible for a subsequent fast retransmit. 678 */ 679 if (rtx_timeout || fast_rtx) { 680 list_for_each_entry(chunk1, lqueue, transmitted_list) { 681 if (chunk1->fast_retransmit == SCTP_NEED_FRTX) 682 chunk1->fast_retransmit = SCTP_DONT_FRTX; 683 } 684 } 685 686 *start_timer = timer; 687 688 /* Clear fast retransmit hint */ 689 if (fast_rtx) 690 q->fast_rtx = 0; 691 692 return error; 693 } 694 695 /* Cork the outqueue so queued chunks are really queued. */ 696 int sctp_outq_uncork(struct sctp_outq *q) 697 { 698 if (q->cork) 699 q->cork = 0; 700 701 return sctp_outq_flush(q, 0); 702 } 703 704 705 /* 706 * Try to flush an outqueue. 707 * 708 * Description: Send everything in q which we legally can, subject to 709 * congestion limitations. 710 * * Note: This function can be called from multiple contexts so appropriate 711 * locking concerns must be made. Today we use the sock lock to protect 712 * this function. 713 */ 714 static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout) 715 { 716 struct sctp_packet *packet; 717 struct sctp_packet singleton; 718 struct sctp_association *asoc = q->asoc; 719 __u16 sport = asoc->base.bind_addr.port; 720 __u16 dport = asoc->peer.port; 721 __u32 vtag = asoc->peer.i.init_tag; 722 struct sctp_transport *transport = NULL; 723 struct sctp_transport *new_transport; 724 struct sctp_chunk *chunk, *tmp; 725 sctp_xmit_t status; 726 int error = 0; 727 int start_timer = 0; 728 int one_packet = 0; 729 730 /* These transports have chunks to send. */ 731 struct list_head transport_list; 732 struct list_head *ltransport; 733 734 INIT_LIST_HEAD(&transport_list); 735 packet = NULL; 736 737 /* 738 * 6.10 Bundling 739 * ... 740 * When bundling control chunks with DATA chunks, an 741 * endpoint MUST place control chunks first in the outbound 742 * SCTP packet. The transmitter MUST transmit DATA chunks 743 * within a SCTP packet in increasing order of TSN. 744 * ... 745 */ 746 747 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) { 748 /* RFC 5061, 5.3 749 * F1) This means that until such time as the ASCONF 750 * containing the add is acknowledged, the sender MUST 751 * NOT use the new IP address as a source for ANY SCTP 752 * packet except on carrying an ASCONF Chunk. 753 */ 754 if (asoc->src_out_of_asoc_ok && 755 chunk->chunk_hdr->type != SCTP_CID_ASCONF) 756 continue; 757 758 list_del_init(&chunk->list); 759 760 /* Pick the right transport to use. */ 761 new_transport = chunk->transport; 762 763 if (!new_transport) { 764 /* 765 * If we have a prior transport pointer, see if 766 * the destination address of the chunk 767 * matches the destination address of the 768 * current transport. If not a match, then 769 * try to look up the transport with a given 770 * destination address. We do this because 771 * after processing ASCONFs, we may have new 772 * transports created. 773 */ 774 if (transport && 775 sctp_cmp_addr_exact(&chunk->dest, 776 &transport->ipaddr)) 777 new_transport = transport; 778 else 779 new_transport = sctp_assoc_lookup_paddr(asoc, 780 &chunk->dest); 781 782 /* if we still don't have a new transport, then 783 * use the current active path. 784 */ 785 if (!new_transport) 786 new_transport = asoc->peer.active_path; 787 } else if ((new_transport->state == SCTP_INACTIVE) || 788 (new_transport->state == SCTP_UNCONFIRMED) || 789 (new_transport->state == SCTP_PF)) { 790 /* If the chunk is Heartbeat or Heartbeat Ack, 791 * send it to chunk->transport, even if it's 792 * inactive. 793 * 794 * 3.3.6 Heartbeat Acknowledgement: 795 * ... 796 * A HEARTBEAT ACK is always sent to the source IP 797 * address of the IP datagram containing the 798 * HEARTBEAT chunk to which this ack is responding. 799 * ... 800 * 801 * ASCONF_ACKs also must be sent to the source. 802 */ 803 if (chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT && 804 chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT_ACK && 805 chunk->chunk_hdr->type != SCTP_CID_ASCONF_ACK) 806 new_transport = asoc->peer.active_path; 807 } 808 809 /* Are we switching transports? 810 * Take care of transport locks. 811 */ 812 if (new_transport != transport) { 813 transport = new_transport; 814 if (list_empty(&transport->send_ready)) { 815 list_add_tail(&transport->send_ready, 816 &transport_list); 817 } 818 packet = &transport->packet; 819 sctp_packet_config(packet, vtag, 820 asoc->peer.ecn_capable); 821 } 822 823 switch (chunk->chunk_hdr->type) { 824 /* 825 * 6.10 Bundling 826 * ... 827 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN 828 * COMPLETE with any other chunks. [Send them immediately.] 829 */ 830 case SCTP_CID_INIT: 831 case SCTP_CID_INIT_ACK: 832 case SCTP_CID_SHUTDOWN_COMPLETE: 833 sctp_packet_init(&singleton, transport, sport, dport); 834 sctp_packet_config(&singleton, vtag, 0); 835 sctp_packet_append_chunk(&singleton, chunk); 836 error = sctp_packet_transmit(&singleton); 837 if (error < 0) 838 return error; 839 break; 840 841 case SCTP_CID_ABORT: 842 if (sctp_test_T_bit(chunk)) { 843 packet->vtag = asoc->c.my_vtag; 844 } 845 /* The following chunks are "response" chunks, i.e. 846 * they are generated in response to something we 847 * received. If we are sending these, then we can 848 * send only 1 packet containing these chunks. 849 */ 850 case SCTP_CID_HEARTBEAT_ACK: 851 case SCTP_CID_SHUTDOWN_ACK: 852 case SCTP_CID_COOKIE_ACK: 853 case SCTP_CID_COOKIE_ECHO: 854 case SCTP_CID_ERROR: 855 case SCTP_CID_ECN_CWR: 856 case SCTP_CID_ASCONF_ACK: 857 one_packet = 1; 858 /* Fall through */ 859 860 case SCTP_CID_SACK: 861 case SCTP_CID_HEARTBEAT: 862 case SCTP_CID_SHUTDOWN: 863 case SCTP_CID_ECN_ECNE: 864 case SCTP_CID_ASCONF: 865 case SCTP_CID_FWD_TSN: 866 status = sctp_packet_transmit_chunk(packet, chunk, 867 one_packet); 868 if (status != SCTP_XMIT_OK) { 869 /* put the chunk back */ 870 list_add(&chunk->list, &q->control_chunk_list); 871 } else { 872 asoc->stats.octrlchunks++; 873 /* PR-SCTP C5) If a FORWARD TSN is sent, the 874 * sender MUST assure that at least one T3-rtx 875 * timer is running. 876 */ 877 if (chunk->chunk_hdr->type == SCTP_CID_FWD_TSN) 878 sctp_transport_reset_timers(transport); 879 } 880 break; 881 882 default: 883 /* We built a chunk with an illegal type! */ 884 BUG(); 885 } 886 } 887 888 if (q->asoc->src_out_of_asoc_ok) 889 goto sctp_flush_out; 890 891 /* Is it OK to send data chunks? */ 892 switch (asoc->state) { 893 case SCTP_STATE_COOKIE_ECHOED: 894 /* Only allow bundling when this packet has a COOKIE-ECHO 895 * chunk. 896 */ 897 if (!packet || !packet->has_cookie_echo) 898 break; 899 900 /* fallthru */ 901 case SCTP_STATE_ESTABLISHED: 902 case SCTP_STATE_SHUTDOWN_PENDING: 903 case SCTP_STATE_SHUTDOWN_RECEIVED: 904 /* 905 * RFC 2960 6.1 Transmission of DATA Chunks 906 * 907 * C) When the time comes for the sender to transmit, 908 * before sending new DATA chunks, the sender MUST 909 * first transmit any outstanding DATA chunks which 910 * are marked for retransmission (limited by the 911 * current cwnd). 912 */ 913 if (!list_empty(&q->retransmit)) { 914 if (asoc->peer.retran_path->state == SCTP_UNCONFIRMED) 915 goto sctp_flush_out; 916 if (transport == asoc->peer.retran_path) 917 goto retran; 918 919 /* Switch transports & prepare the packet. */ 920 921 transport = asoc->peer.retran_path; 922 923 if (list_empty(&transport->send_ready)) { 924 list_add_tail(&transport->send_ready, 925 &transport_list); 926 } 927 928 packet = &transport->packet; 929 sctp_packet_config(packet, vtag, 930 asoc->peer.ecn_capable); 931 retran: 932 error = sctp_outq_flush_rtx(q, packet, 933 rtx_timeout, &start_timer); 934 935 if (start_timer) 936 sctp_transport_reset_timers(transport); 937 938 /* This can happen on COOKIE-ECHO resend. Only 939 * one chunk can get bundled with a COOKIE-ECHO. 940 */ 941 if (packet->has_cookie_echo) 942 goto sctp_flush_out; 943 944 /* Don't send new data if there is still data 945 * waiting to retransmit. 946 */ 947 if (!list_empty(&q->retransmit)) 948 goto sctp_flush_out; 949 } 950 951 /* Apply Max.Burst limitation to the current transport in 952 * case it will be used for new data. We are going to 953 * rest it before we return, but we want to apply the limit 954 * to the currently queued data. 955 */ 956 if (transport) 957 sctp_transport_burst_limited(transport); 958 959 /* Finally, transmit new packets. */ 960 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) { 961 /* RFC 2960 6.5 Every DATA chunk MUST carry a valid 962 * stream identifier. 963 */ 964 if (chunk->sinfo.sinfo_stream >= 965 asoc->c.sinit_num_ostreams) { 966 967 /* Mark as failed send. */ 968 sctp_chunk_fail(chunk, SCTP_ERROR_INV_STRM); 969 sctp_chunk_free(chunk); 970 continue; 971 } 972 973 /* Has this chunk expired? */ 974 if (sctp_chunk_abandoned(chunk)) { 975 sctp_chunk_fail(chunk, 0); 976 sctp_chunk_free(chunk); 977 continue; 978 } 979 980 /* If there is a specified transport, use it. 981 * Otherwise, we want to use the active path. 982 */ 983 new_transport = chunk->transport; 984 if (!new_transport || 985 ((new_transport->state == SCTP_INACTIVE) || 986 (new_transport->state == SCTP_UNCONFIRMED) || 987 (new_transport->state == SCTP_PF))) 988 new_transport = asoc->peer.active_path; 989 if (new_transport->state == SCTP_UNCONFIRMED) 990 continue; 991 992 /* Change packets if necessary. */ 993 if (new_transport != transport) { 994 transport = new_transport; 995 996 /* Schedule to have this transport's 997 * packet flushed. 998 */ 999 if (list_empty(&transport->send_ready)) { 1000 list_add_tail(&transport->send_ready, 1001 &transport_list); 1002 } 1003 1004 packet = &transport->packet; 1005 sctp_packet_config(packet, vtag, 1006 asoc->peer.ecn_capable); 1007 /* We've switched transports, so apply the 1008 * Burst limit to the new transport. 1009 */ 1010 sctp_transport_burst_limited(transport); 1011 } 1012 1013 pr_debug("%s: outq:%p, chunk:%p[%s], tx-tsn:0x%x skb->head:%p " 1014 "skb->users:%d\n", 1015 __func__, q, chunk, chunk && chunk->chunk_hdr ? 1016 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) : 1017 "illegal chunk", ntohl(chunk->subh.data_hdr->tsn), 1018 chunk->skb ? chunk->skb->head : NULL, chunk->skb ? 1019 atomic_read(&chunk->skb->users) : -1); 1020 1021 /* Add the chunk to the packet. */ 1022 status = sctp_packet_transmit_chunk(packet, chunk, 0); 1023 1024 switch (status) { 1025 case SCTP_XMIT_PMTU_FULL: 1026 case SCTP_XMIT_RWND_FULL: 1027 case SCTP_XMIT_NAGLE_DELAY: 1028 /* We could not append this chunk, so put 1029 * the chunk back on the output queue. 1030 */ 1031 pr_debug("%s: could not transmit tsn:0x%x, status:%d\n", 1032 __func__, ntohl(chunk->subh.data_hdr->tsn), 1033 status); 1034 1035 sctp_outq_head_data(q, chunk); 1036 goto sctp_flush_out; 1037 break; 1038 1039 case SCTP_XMIT_OK: 1040 /* The sender is in the SHUTDOWN-PENDING state, 1041 * The sender MAY set the I-bit in the DATA 1042 * chunk header. 1043 */ 1044 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING) 1045 chunk->chunk_hdr->flags |= SCTP_DATA_SACK_IMM; 1046 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) 1047 asoc->stats.ouodchunks++; 1048 else 1049 asoc->stats.oodchunks++; 1050 1051 break; 1052 1053 default: 1054 BUG(); 1055 } 1056 1057 /* BUG: We assume that the sctp_packet_transmit() 1058 * call below will succeed all the time and add the 1059 * chunk to the transmitted list and restart the 1060 * timers. 1061 * It is possible that the call can fail under OOM 1062 * conditions. 1063 * 1064 * Is this really a problem? Won't this behave 1065 * like a lost TSN? 1066 */ 1067 list_add_tail(&chunk->transmitted_list, 1068 &transport->transmitted); 1069 1070 sctp_transport_reset_timers(transport); 1071 1072 q->empty = 0; 1073 1074 /* Only let one DATA chunk get bundled with a 1075 * COOKIE-ECHO chunk. 1076 */ 1077 if (packet->has_cookie_echo) 1078 goto sctp_flush_out; 1079 } 1080 break; 1081 1082 default: 1083 /* Do nothing. */ 1084 break; 1085 } 1086 1087 sctp_flush_out: 1088 1089 /* Before returning, examine all the transports touched in 1090 * this call. Right now, we bluntly force clear all the 1091 * transports. Things might change after we implement Nagle. 1092 * But such an examination is still required. 1093 * 1094 * --xguo 1095 */ 1096 while ((ltransport = sctp_list_dequeue(&transport_list)) != NULL ) { 1097 struct sctp_transport *t = list_entry(ltransport, 1098 struct sctp_transport, 1099 send_ready); 1100 packet = &t->packet; 1101 if (!sctp_packet_empty(packet)) 1102 error = sctp_packet_transmit(packet); 1103 1104 /* Clear the burst limited state, if any */ 1105 sctp_transport_burst_reset(t); 1106 } 1107 1108 return error; 1109 } 1110 1111 /* Update unack_data based on the incoming SACK chunk */ 1112 static void sctp_sack_update_unack_data(struct sctp_association *assoc, 1113 struct sctp_sackhdr *sack) 1114 { 1115 sctp_sack_variable_t *frags; 1116 __u16 unack_data; 1117 int i; 1118 1119 unack_data = assoc->next_tsn - assoc->ctsn_ack_point - 1; 1120 1121 frags = sack->variable; 1122 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); i++) { 1123 unack_data -= ((ntohs(frags[i].gab.end) - 1124 ntohs(frags[i].gab.start) + 1)); 1125 } 1126 1127 assoc->unack_data = unack_data; 1128 } 1129 1130 /* This is where we REALLY process a SACK. 1131 * 1132 * Process the SACK against the outqueue. Mostly, this just frees 1133 * things off the transmitted queue. 1134 */ 1135 int sctp_outq_sack(struct sctp_outq *q, struct sctp_chunk *chunk) 1136 { 1137 struct sctp_association *asoc = q->asoc; 1138 struct sctp_sackhdr *sack = chunk->subh.sack_hdr; 1139 struct sctp_transport *transport; 1140 struct sctp_chunk *tchunk = NULL; 1141 struct list_head *lchunk, *transport_list, *temp; 1142 sctp_sack_variable_t *frags = sack->variable; 1143 __u32 sack_ctsn, ctsn, tsn; 1144 __u32 highest_tsn, highest_new_tsn; 1145 __u32 sack_a_rwnd; 1146 unsigned int outstanding; 1147 struct sctp_transport *primary = asoc->peer.primary_path; 1148 int count_of_newacks = 0; 1149 int gap_ack_blocks; 1150 u8 accum_moved = 0; 1151 1152 /* Grab the association's destination address list. */ 1153 transport_list = &asoc->peer.transport_addr_list; 1154 1155 sack_ctsn = ntohl(sack->cum_tsn_ack); 1156 gap_ack_blocks = ntohs(sack->num_gap_ack_blocks); 1157 asoc->stats.gapcnt += gap_ack_blocks; 1158 /* 1159 * SFR-CACC algorithm: 1160 * On receipt of a SACK the sender SHOULD execute the 1161 * following statements. 1162 * 1163 * 1) If the cumulative ack in the SACK passes next tsn_at_change 1164 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be 1165 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for 1166 * all destinations. 1167 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE 1168 * is set the receiver of the SACK MUST take the following actions: 1169 * 1170 * A) Initialize the cacc_saw_newack to 0 for all destination 1171 * addresses. 1172 * 1173 * Only bother if changeover_active is set. Otherwise, this is 1174 * totally suboptimal to do on every SACK. 1175 */ 1176 if (primary->cacc.changeover_active) { 1177 u8 clear_cycling = 0; 1178 1179 if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) { 1180 primary->cacc.changeover_active = 0; 1181 clear_cycling = 1; 1182 } 1183 1184 if (clear_cycling || gap_ack_blocks) { 1185 list_for_each_entry(transport, transport_list, 1186 transports) { 1187 if (clear_cycling) 1188 transport->cacc.cycling_changeover = 0; 1189 if (gap_ack_blocks) 1190 transport->cacc.cacc_saw_newack = 0; 1191 } 1192 } 1193 } 1194 1195 /* Get the highest TSN in the sack. */ 1196 highest_tsn = sack_ctsn; 1197 if (gap_ack_blocks) 1198 highest_tsn += ntohs(frags[gap_ack_blocks - 1].gab.end); 1199 1200 if (TSN_lt(asoc->highest_sacked, highest_tsn)) 1201 asoc->highest_sacked = highest_tsn; 1202 1203 highest_new_tsn = sack_ctsn; 1204 1205 /* Run through the retransmit queue. Credit bytes received 1206 * and free those chunks that we can. 1207 */ 1208 sctp_check_transmitted(q, &q->retransmit, NULL, NULL, sack, &highest_new_tsn); 1209 1210 /* Run through the transmitted queue. 1211 * Credit bytes received and free those chunks which we can. 1212 * 1213 * This is a MASSIVE candidate for optimization. 1214 */ 1215 list_for_each_entry(transport, transport_list, transports) { 1216 sctp_check_transmitted(q, &transport->transmitted, 1217 transport, &chunk->source, sack, 1218 &highest_new_tsn); 1219 /* 1220 * SFR-CACC algorithm: 1221 * C) Let count_of_newacks be the number of 1222 * destinations for which cacc_saw_newack is set. 1223 */ 1224 if (transport->cacc.cacc_saw_newack) 1225 count_of_newacks ++; 1226 } 1227 1228 /* Move the Cumulative TSN Ack Point if appropriate. */ 1229 if (TSN_lt(asoc->ctsn_ack_point, sack_ctsn)) { 1230 asoc->ctsn_ack_point = sack_ctsn; 1231 accum_moved = 1; 1232 } 1233 1234 if (gap_ack_blocks) { 1235 1236 if (asoc->fast_recovery && accum_moved) 1237 highest_new_tsn = highest_tsn; 1238 1239 list_for_each_entry(transport, transport_list, transports) 1240 sctp_mark_missing(q, &transport->transmitted, transport, 1241 highest_new_tsn, count_of_newacks); 1242 } 1243 1244 /* Update unack_data field in the assoc. */ 1245 sctp_sack_update_unack_data(asoc, sack); 1246 1247 ctsn = asoc->ctsn_ack_point; 1248 1249 /* Throw away stuff rotting on the sack queue. */ 1250 list_for_each_safe(lchunk, temp, &q->sacked) { 1251 tchunk = list_entry(lchunk, struct sctp_chunk, 1252 transmitted_list); 1253 tsn = ntohl(tchunk->subh.data_hdr->tsn); 1254 if (TSN_lte(tsn, ctsn)) { 1255 list_del_init(&tchunk->transmitted_list); 1256 sctp_chunk_free(tchunk); 1257 } 1258 } 1259 1260 /* ii) Set rwnd equal to the newly received a_rwnd minus the 1261 * number of bytes still outstanding after processing the 1262 * Cumulative TSN Ack and the Gap Ack Blocks. 1263 */ 1264 1265 sack_a_rwnd = ntohl(sack->a_rwnd); 1266 outstanding = q->outstanding_bytes; 1267 1268 if (outstanding < sack_a_rwnd) 1269 sack_a_rwnd -= outstanding; 1270 else 1271 sack_a_rwnd = 0; 1272 1273 asoc->peer.rwnd = sack_a_rwnd; 1274 1275 sctp_generate_fwdtsn(q, sack_ctsn); 1276 1277 pr_debug("%s: sack cumulative tsn ack:0x%x\n", __func__, sack_ctsn); 1278 pr_debug("%s: cumulative tsn ack of assoc:%p is 0x%x, " 1279 "advertised peer ack point:0x%x\n", __func__, asoc, ctsn, 1280 asoc->adv_peer_ack_point); 1281 1282 /* See if all chunks are acked. 1283 * Make sure the empty queue handler will get run later. 1284 */ 1285 q->empty = (list_empty(&q->out_chunk_list) && 1286 list_empty(&q->retransmit)); 1287 if (!q->empty) 1288 goto finish; 1289 1290 list_for_each_entry(transport, transport_list, transports) { 1291 q->empty = q->empty && list_empty(&transport->transmitted); 1292 if (!q->empty) 1293 goto finish; 1294 } 1295 1296 pr_debug("%s: sack queue is empty\n", __func__); 1297 finish: 1298 return q->empty; 1299 } 1300 1301 /* Is the outqueue empty? */ 1302 int sctp_outq_is_empty(const struct sctp_outq *q) 1303 { 1304 return q->empty; 1305 } 1306 1307 /******************************************************************** 1308 * 2nd Level Abstractions 1309 ********************************************************************/ 1310 1311 /* Go through a transport's transmitted list or the association's retransmit 1312 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked. 1313 * The retransmit list will not have an associated transport. 1314 * 1315 * I added coherent debug information output. --xguo 1316 * 1317 * Instead of printing 'sacked' or 'kept' for each TSN on the 1318 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5. 1319 * KEPT TSN6-TSN7, etc. 1320 */ 1321 static void sctp_check_transmitted(struct sctp_outq *q, 1322 struct list_head *transmitted_queue, 1323 struct sctp_transport *transport, 1324 union sctp_addr *saddr, 1325 struct sctp_sackhdr *sack, 1326 __u32 *highest_new_tsn_in_sack) 1327 { 1328 struct list_head *lchunk; 1329 struct sctp_chunk *tchunk; 1330 struct list_head tlist; 1331 __u32 tsn; 1332 __u32 sack_ctsn; 1333 __u32 rtt; 1334 __u8 restart_timer = 0; 1335 int bytes_acked = 0; 1336 int migrate_bytes = 0; 1337 bool forward_progress = false; 1338 1339 sack_ctsn = ntohl(sack->cum_tsn_ack); 1340 1341 INIT_LIST_HEAD(&tlist); 1342 1343 /* The while loop will skip empty transmitted queues. */ 1344 while (NULL != (lchunk = sctp_list_dequeue(transmitted_queue))) { 1345 tchunk = list_entry(lchunk, struct sctp_chunk, 1346 transmitted_list); 1347 1348 if (sctp_chunk_abandoned(tchunk)) { 1349 /* Move the chunk to abandoned list. */ 1350 sctp_insert_list(&q->abandoned, lchunk); 1351 1352 /* If this chunk has not been acked, stop 1353 * considering it as 'outstanding'. 1354 */ 1355 if (!tchunk->tsn_gap_acked) { 1356 if (tchunk->transport) 1357 tchunk->transport->flight_size -= 1358 sctp_data_size(tchunk); 1359 q->outstanding_bytes -= sctp_data_size(tchunk); 1360 } 1361 continue; 1362 } 1363 1364 tsn = ntohl(tchunk->subh.data_hdr->tsn); 1365 if (sctp_acked(sack, tsn)) { 1366 /* If this queue is the retransmit queue, the 1367 * retransmit timer has already reclaimed 1368 * the outstanding bytes for this chunk, so only 1369 * count bytes associated with a transport. 1370 */ 1371 if (transport) { 1372 /* If this chunk is being used for RTT 1373 * measurement, calculate the RTT and update 1374 * the RTO using this value. 1375 * 1376 * 6.3.1 C5) Karn's algorithm: RTT measurements 1377 * MUST NOT be made using packets that were 1378 * retransmitted (and thus for which it is 1379 * ambiguous whether the reply was for the 1380 * first instance of the packet or a later 1381 * instance). 1382 */ 1383 if (!tchunk->tsn_gap_acked && 1384 tchunk->rtt_in_progress) { 1385 tchunk->rtt_in_progress = 0; 1386 rtt = jiffies - tchunk->sent_at; 1387 sctp_transport_update_rto(transport, 1388 rtt); 1389 } 1390 } 1391 1392 /* If the chunk hasn't been marked as ACKED, 1393 * mark it and account bytes_acked if the 1394 * chunk had a valid transport (it will not 1395 * have a transport if ASCONF had deleted it 1396 * while DATA was outstanding). 1397 */ 1398 if (!tchunk->tsn_gap_acked) { 1399 tchunk->tsn_gap_acked = 1; 1400 *highest_new_tsn_in_sack = tsn; 1401 bytes_acked += sctp_data_size(tchunk); 1402 if (!tchunk->transport) 1403 migrate_bytes += sctp_data_size(tchunk); 1404 forward_progress = true; 1405 } 1406 1407 if (TSN_lte(tsn, sack_ctsn)) { 1408 /* RFC 2960 6.3.2 Retransmission Timer Rules 1409 * 1410 * R3) Whenever a SACK is received 1411 * that acknowledges the DATA chunk 1412 * with the earliest outstanding TSN 1413 * for that address, restart T3-rtx 1414 * timer for that address with its 1415 * current RTO. 1416 */ 1417 restart_timer = 1; 1418 forward_progress = true; 1419 1420 if (!tchunk->tsn_gap_acked) { 1421 /* 1422 * SFR-CACC algorithm: 1423 * 2) If the SACK contains gap acks 1424 * and the flag CHANGEOVER_ACTIVE is 1425 * set the receiver of the SACK MUST 1426 * take the following action: 1427 * 1428 * B) For each TSN t being acked that 1429 * has not been acked in any SACK so 1430 * far, set cacc_saw_newack to 1 for 1431 * the destination that the TSN was 1432 * sent to. 1433 */ 1434 if (transport && 1435 sack->num_gap_ack_blocks && 1436 q->asoc->peer.primary_path->cacc. 1437 changeover_active) 1438 transport->cacc.cacc_saw_newack 1439 = 1; 1440 } 1441 1442 list_add_tail(&tchunk->transmitted_list, 1443 &q->sacked); 1444 } else { 1445 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2 1446 * M2) Each time a SACK arrives reporting 1447 * 'Stray DATA chunk(s)' record the highest TSN 1448 * reported as newly acknowledged, call this 1449 * value 'HighestTSNinSack'. A newly 1450 * acknowledged DATA chunk is one not 1451 * previously acknowledged in a SACK. 1452 * 1453 * When the SCTP sender of data receives a SACK 1454 * chunk that acknowledges, for the first time, 1455 * the receipt of a DATA chunk, all the still 1456 * unacknowledged DATA chunks whose TSN is 1457 * older than that newly acknowledged DATA 1458 * chunk, are qualified as 'Stray DATA chunks'. 1459 */ 1460 list_add_tail(lchunk, &tlist); 1461 } 1462 } else { 1463 if (tchunk->tsn_gap_acked) { 1464 pr_debug("%s: receiver reneged on data TSN:0x%x\n", 1465 __func__, tsn); 1466 1467 tchunk->tsn_gap_acked = 0; 1468 1469 if (tchunk->transport) 1470 bytes_acked -= sctp_data_size(tchunk); 1471 1472 /* RFC 2960 6.3.2 Retransmission Timer Rules 1473 * 1474 * R4) Whenever a SACK is received missing a 1475 * TSN that was previously acknowledged via a 1476 * Gap Ack Block, start T3-rtx for the 1477 * destination address to which the DATA 1478 * chunk was originally 1479 * transmitted if it is not already running. 1480 */ 1481 restart_timer = 1; 1482 } 1483 1484 list_add_tail(lchunk, &tlist); 1485 } 1486 } 1487 1488 if (transport) { 1489 if (bytes_acked) { 1490 struct sctp_association *asoc = transport->asoc; 1491 1492 /* We may have counted DATA that was migrated 1493 * to this transport due to DEL-IP operation. 1494 * Subtract those bytes, since the were never 1495 * send on this transport and shouldn't be 1496 * credited to this transport. 1497 */ 1498 bytes_acked -= migrate_bytes; 1499 1500 /* 8.2. When an outstanding TSN is acknowledged, 1501 * the endpoint shall clear the error counter of 1502 * the destination transport address to which the 1503 * DATA chunk was last sent. 1504 * The association's overall error counter is 1505 * also cleared. 1506 */ 1507 transport->error_count = 0; 1508 transport->asoc->overall_error_count = 0; 1509 forward_progress = true; 1510 1511 /* 1512 * While in SHUTDOWN PENDING, we may have started 1513 * the T5 shutdown guard timer after reaching the 1514 * retransmission limit. Stop that timer as soon 1515 * as the receiver acknowledged any data. 1516 */ 1517 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING && 1518 del_timer(&asoc->timers 1519 [SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD])) 1520 sctp_association_put(asoc); 1521 1522 /* Mark the destination transport address as 1523 * active if it is not so marked. 1524 */ 1525 if ((transport->state == SCTP_INACTIVE || 1526 transport->state == SCTP_UNCONFIRMED) && 1527 sctp_cmp_addr_exact(&transport->ipaddr, saddr)) { 1528 sctp_assoc_control_transport( 1529 transport->asoc, 1530 transport, 1531 SCTP_TRANSPORT_UP, 1532 SCTP_RECEIVED_SACK); 1533 } 1534 1535 sctp_transport_raise_cwnd(transport, sack_ctsn, 1536 bytes_acked); 1537 1538 transport->flight_size -= bytes_acked; 1539 if (transport->flight_size == 0) 1540 transport->partial_bytes_acked = 0; 1541 q->outstanding_bytes -= bytes_acked + migrate_bytes; 1542 } else { 1543 /* RFC 2960 6.1, sctpimpguide-06 2.15.2 1544 * When a sender is doing zero window probing, it 1545 * should not timeout the association if it continues 1546 * to receive new packets from the receiver. The 1547 * reason is that the receiver MAY keep its window 1548 * closed for an indefinite time. 1549 * A sender is doing zero window probing when the 1550 * receiver's advertised window is zero, and there is 1551 * only one data chunk in flight to the receiver. 1552 * 1553 * Allow the association to timeout while in SHUTDOWN 1554 * PENDING or SHUTDOWN RECEIVED in case the receiver 1555 * stays in zero window mode forever. 1556 */ 1557 if (!q->asoc->peer.rwnd && 1558 !list_empty(&tlist) && 1559 (sack_ctsn+2 == q->asoc->next_tsn) && 1560 q->asoc->state < SCTP_STATE_SHUTDOWN_PENDING) { 1561 pr_debug("%s: sack received for zero window " 1562 "probe:%u\n", __func__, sack_ctsn); 1563 1564 q->asoc->overall_error_count = 0; 1565 transport->error_count = 0; 1566 } 1567 } 1568 1569 /* RFC 2960 6.3.2 Retransmission Timer Rules 1570 * 1571 * R2) Whenever all outstanding data sent to an address have 1572 * been acknowledged, turn off the T3-rtx timer of that 1573 * address. 1574 */ 1575 if (!transport->flight_size) { 1576 if (del_timer(&transport->T3_rtx_timer)) 1577 sctp_transport_put(transport); 1578 } else if (restart_timer) { 1579 if (!mod_timer(&transport->T3_rtx_timer, 1580 jiffies + transport->rto)) 1581 sctp_transport_hold(transport); 1582 } 1583 1584 if (forward_progress) { 1585 if (transport->dst) 1586 dst_confirm(transport->dst); 1587 } 1588 } 1589 1590 list_splice(&tlist, transmitted_queue); 1591 } 1592 1593 /* Mark chunks as missing and consequently may get retransmitted. */ 1594 static void sctp_mark_missing(struct sctp_outq *q, 1595 struct list_head *transmitted_queue, 1596 struct sctp_transport *transport, 1597 __u32 highest_new_tsn_in_sack, 1598 int count_of_newacks) 1599 { 1600 struct sctp_chunk *chunk; 1601 __u32 tsn; 1602 char do_fast_retransmit = 0; 1603 struct sctp_association *asoc = q->asoc; 1604 struct sctp_transport *primary = asoc->peer.primary_path; 1605 1606 list_for_each_entry(chunk, transmitted_queue, transmitted_list) { 1607 1608 tsn = ntohl(chunk->subh.data_hdr->tsn); 1609 1610 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all 1611 * 'Unacknowledged TSN's', if the TSN number of an 1612 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack' 1613 * value, increment the 'TSN.Missing.Report' count on that 1614 * chunk if it has NOT been fast retransmitted or marked for 1615 * fast retransmit already. 1616 */ 1617 if (chunk->fast_retransmit == SCTP_CAN_FRTX && 1618 !chunk->tsn_gap_acked && 1619 TSN_lt(tsn, highest_new_tsn_in_sack)) { 1620 1621 /* SFR-CACC may require us to skip marking 1622 * this chunk as missing. 1623 */ 1624 if (!transport || !sctp_cacc_skip(primary, 1625 chunk->transport, 1626 count_of_newacks, tsn)) { 1627 chunk->tsn_missing_report++; 1628 1629 pr_debug("%s: tsn:0x%x missing counter:%d\n", 1630 __func__, tsn, chunk->tsn_missing_report); 1631 } 1632 } 1633 /* 1634 * M4) If any DATA chunk is found to have a 1635 * 'TSN.Missing.Report' 1636 * value larger than or equal to 3, mark that chunk for 1637 * retransmission and start the fast retransmit procedure. 1638 */ 1639 1640 if (chunk->tsn_missing_report >= 3) { 1641 chunk->fast_retransmit = SCTP_NEED_FRTX; 1642 do_fast_retransmit = 1; 1643 } 1644 } 1645 1646 if (transport) { 1647 if (do_fast_retransmit) 1648 sctp_retransmit(q, transport, SCTP_RTXR_FAST_RTX); 1649 1650 pr_debug("%s: transport:%p, cwnd:%d, ssthresh:%d, " 1651 "flight_size:%d, pba:%d\n", __func__, transport, 1652 transport->cwnd, transport->ssthresh, 1653 transport->flight_size, transport->partial_bytes_acked); 1654 } 1655 } 1656 1657 /* Is the given TSN acked by this packet? */ 1658 static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn) 1659 { 1660 int i; 1661 sctp_sack_variable_t *frags; 1662 __u16 gap; 1663 __u32 ctsn = ntohl(sack->cum_tsn_ack); 1664 1665 if (TSN_lte(tsn, ctsn)) 1666 goto pass; 1667 1668 /* 3.3.4 Selective Acknowledgement (SACK) (3): 1669 * 1670 * Gap Ack Blocks: 1671 * These fields contain the Gap Ack Blocks. They are repeated 1672 * for each Gap Ack Block up to the number of Gap Ack Blocks 1673 * defined in the Number of Gap Ack Blocks field. All DATA 1674 * chunks with TSNs greater than or equal to (Cumulative TSN 1675 * Ack + Gap Ack Block Start) and less than or equal to 1676 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack 1677 * Block are assumed to have been received correctly. 1678 */ 1679 1680 frags = sack->variable; 1681 gap = tsn - ctsn; 1682 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); ++i) { 1683 if (TSN_lte(ntohs(frags[i].gab.start), gap) && 1684 TSN_lte(gap, ntohs(frags[i].gab.end))) 1685 goto pass; 1686 } 1687 1688 return 0; 1689 pass: 1690 return 1; 1691 } 1692 1693 static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip *skiplist, 1694 int nskips, __be16 stream) 1695 { 1696 int i; 1697 1698 for (i = 0; i < nskips; i++) { 1699 if (skiplist[i].stream == stream) 1700 return i; 1701 } 1702 return i; 1703 } 1704 1705 /* Create and add a fwdtsn chunk to the outq's control queue if needed. */ 1706 static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 ctsn) 1707 { 1708 struct sctp_association *asoc = q->asoc; 1709 struct sctp_chunk *ftsn_chunk = NULL; 1710 struct sctp_fwdtsn_skip ftsn_skip_arr[10]; 1711 int nskips = 0; 1712 int skip_pos = 0; 1713 __u32 tsn; 1714 struct sctp_chunk *chunk; 1715 struct list_head *lchunk, *temp; 1716 1717 if (!asoc->peer.prsctp_capable) 1718 return; 1719 1720 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the 1721 * received SACK. 1722 * 1723 * If (Advanced.Peer.Ack.Point < SackCumAck), then update 1724 * Advanced.Peer.Ack.Point to be equal to SackCumAck. 1725 */ 1726 if (TSN_lt(asoc->adv_peer_ack_point, ctsn)) 1727 asoc->adv_peer_ack_point = ctsn; 1728 1729 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point" 1730 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as 1731 * the chunk next in the out-queue space is marked as "abandoned" as 1732 * shown in the following example: 1733 * 1734 * Assuming that a SACK arrived with the Cumulative TSN ACK 102 1735 * and the Advanced.Peer.Ack.Point is updated to this value: 1736 * 1737 * out-queue at the end of ==> out-queue after Adv.Ack.Point 1738 * normal SACK processing local advancement 1739 * ... ... 1740 * Adv.Ack.Pt-> 102 acked 102 acked 1741 * 103 abandoned 103 abandoned 1742 * 104 abandoned Adv.Ack.P-> 104 abandoned 1743 * 105 105 1744 * 106 acked 106 acked 1745 * ... ... 1746 * 1747 * In this example, the data sender successfully advanced the 1748 * "Advanced.Peer.Ack.Point" from 102 to 104 locally. 1749 */ 1750 list_for_each_safe(lchunk, temp, &q->abandoned) { 1751 chunk = list_entry(lchunk, struct sctp_chunk, 1752 transmitted_list); 1753 tsn = ntohl(chunk->subh.data_hdr->tsn); 1754 1755 /* Remove any chunks in the abandoned queue that are acked by 1756 * the ctsn. 1757 */ 1758 if (TSN_lte(tsn, ctsn)) { 1759 list_del_init(lchunk); 1760 sctp_chunk_free(chunk); 1761 } else { 1762 if (TSN_lte(tsn, asoc->adv_peer_ack_point+1)) { 1763 asoc->adv_peer_ack_point = tsn; 1764 if (chunk->chunk_hdr->flags & 1765 SCTP_DATA_UNORDERED) 1766 continue; 1767 skip_pos = sctp_get_skip_pos(&ftsn_skip_arr[0], 1768 nskips, 1769 chunk->subh.data_hdr->stream); 1770 ftsn_skip_arr[skip_pos].stream = 1771 chunk->subh.data_hdr->stream; 1772 ftsn_skip_arr[skip_pos].ssn = 1773 chunk->subh.data_hdr->ssn; 1774 if (skip_pos == nskips) 1775 nskips++; 1776 if (nskips == 10) 1777 break; 1778 } else 1779 break; 1780 } 1781 } 1782 1783 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point" 1784 * is greater than the Cumulative TSN ACK carried in the received 1785 * SACK, the data sender MUST send the data receiver a FORWARD TSN 1786 * chunk containing the latest value of the 1787 * "Advanced.Peer.Ack.Point". 1788 * 1789 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD 1790 * list each stream and sequence number in the forwarded TSN. This 1791 * information will enable the receiver to easily find any 1792 * stranded TSN's waiting on stream reorder queues. Each stream 1793 * SHOULD only be reported once; this means that if multiple 1794 * abandoned messages occur in the same stream then only the 1795 * highest abandoned stream sequence number is reported. If the 1796 * total size of the FORWARD TSN does NOT fit in a single MTU then 1797 * the sender of the FORWARD TSN SHOULD lower the 1798 * Advanced.Peer.Ack.Point to the last TSN that will fit in a 1799 * single MTU. 1800 */ 1801 if (asoc->adv_peer_ack_point > ctsn) 1802 ftsn_chunk = sctp_make_fwdtsn(asoc, asoc->adv_peer_ack_point, 1803 nskips, &ftsn_skip_arr[0]); 1804 1805 if (ftsn_chunk) { 1806 list_add_tail(&ftsn_chunk->list, &q->control_chunk_list); 1807 SCTP_INC_STATS(sock_net(asoc->base.sk), SCTP_MIB_OUTCTRLCHUNKS); 1808 } 1809 } 1810