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, see 26 * <http://www.gnu.org/licenses/>. 27 * 28 * Please send any bug reports or fixes you make to the 29 * email address(es): 30 * lksctp developers <linux-sctp@vger.kernel.org> 31 * 32 * Written or modified by: 33 * La Monte H.P. Yarroll <piggy@acm.org> 34 * Karl Knutson <karl@athena.chicago.il.us> 35 * Perry Melange <pmelange@null.cc.uic.edu> 36 * Xingang Guo <xingang.guo@intel.com> 37 * Hui Huang <hui.huang@nokia.com> 38 * Sridhar Samudrala <sri@us.ibm.com> 39 * Jon Grimm <jgrimm@us.ibm.com> 40 */ 41 42 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 43 44 #include <linux/types.h> 45 #include <linux/list.h> /* For struct list_head */ 46 #include <linux/socket.h> 47 #include <linux/ip.h> 48 #include <linux/slab.h> 49 #include <net/sock.h> /* For skb_set_owner_w */ 50 51 #include <net/sctp/sctp.h> 52 #include <net/sctp/sm.h> 53 54 /* Declare internal functions here. */ 55 static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn); 56 static void sctp_check_transmitted(struct sctp_outq *q, 57 struct list_head *transmitted_queue, 58 struct sctp_transport *transport, 59 union sctp_addr *saddr, 60 struct sctp_sackhdr *sack, 61 __u32 *highest_new_tsn); 62 63 static void sctp_mark_missing(struct sctp_outq *q, 64 struct list_head *transmitted_queue, 65 struct sctp_transport *transport, 66 __u32 highest_new_tsn, 67 int count_of_newacks); 68 69 static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 sack_ctsn); 70 71 static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout, gfp_t gfp); 72 73 /* Add data to the front of the queue. */ 74 static inline void sctp_outq_head_data(struct sctp_outq *q, 75 struct sctp_chunk *ch) 76 { 77 list_add(&ch->list, &q->out_chunk_list); 78 q->out_qlen += ch->skb->len; 79 } 80 81 /* Take data from the front of the queue. */ 82 static inline struct sctp_chunk *sctp_outq_dequeue_data(struct sctp_outq *q) 83 { 84 struct sctp_chunk *ch = NULL; 85 86 if (!list_empty(&q->out_chunk_list)) { 87 struct list_head *entry = q->out_chunk_list.next; 88 89 ch = list_entry(entry, struct sctp_chunk, list); 90 list_del_init(entry); 91 q->out_qlen -= ch->skb->len; 92 } 93 return ch; 94 } 95 /* Add data chunk to the end of the queue. */ 96 static inline void sctp_outq_tail_data(struct sctp_outq *q, 97 struct sctp_chunk *ch) 98 { 99 list_add_tail(&ch->list, &q->out_chunk_list); 100 q->out_qlen += ch->skb->len; 101 } 102 103 /* 104 * SFR-CACC algorithm: 105 * D) If count_of_newacks is greater than or equal to 2 106 * and t was not sent to the current primary then the 107 * sender MUST NOT increment missing report count for t. 108 */ 109 static inline int sctp_cacc_skip_3_1_d(struct sctp_transport *primary, 110 struct sctp_transport *transport, 111 int count_of_newacks) 112 { 113 if (count_of_newacks >= 2 && transport != primary) 114 return 1; 115 return 0; 116 } 117 118 /* 119 * SFR-CACC algorithm: 120 * F) If count_of_newacks is less than 2, let d be the 121 * destination to which t was sent. If cacc_saw_newack 122 * is 0 for destination d, then the sender MUST NOT 123 * increment missing report count for t. 124 */ 125 static inline int sctp_cacc_skip_3_1_f(struct sctp_transport *transport, 126 int count_of_newacks) 127 { 128 if (count_of_newacks < 2 && 129 (transport && !transport->cacc.cacc_saw_newack)) 130 return 1; 131 return 0; 132 } 133 134 /* 135 * SFR-CACC algorithm: 136 * 3.1) If CYCLING_CHANGEOVER is 0, the sender SHOULD 137 * execute steps C, D, F. 138 * 139 * C has been implemented in sctp_outq_sack 140 */ 141 static inline int sctp_cacc_skip_3_1(struct sctp_transport *primary, 142 struct sctp_transport *transport, 143 int count_of_newacks) 144 { 145 if (!primary->cacc.cycling_changeover) { 146 if (sctp_cacc_skip_3_1_d(primary, transport, count_of_newacks)) 147 return 1; 148 if (sctp_cacc_skip_3_1_f(transport, count_of_newacks)) 149 return 1; 150 return 0; 151 } 152 return 0; 153 } 154 155 /* 156 * SFR-CACC algorithm: 157 * 3.2) Else if CYCLING_CHANGEOVER is 1, and t is less 158 * than next_tsn_at_change of the current primary, then 159 * the sender MUST NOT increment missing report count 160 * for t. 161 */ 162 static inline int sctp_cacc_skip_3_2(struct sctp_transport *primary, __u32 tsn) 163 { 164 if (primary->cacc.cycling_changeover && 165 TSN_lt(tsn, primary->cacc.next_tsn_at_change)) 166 return 1; 167 return 0; 168 } 169 170 /* 171 * SFR-CACC algorithm: 172 * 3) If the missing report count for TSN t is to be 173 * incremented according to [RFC2960] and 174 * [SCTP_STEWART-2002], and CHANGEOVER_ACTIVE is set, 175 * then the sender MUST further execute steps 3.1 and 176 * 3.2 to determine if the missing report count for 177 * TSN t SHOULD NOT be incremented. 178 * 179 * 3.3) If 3.1 and 3.2 do not dictate that the missing 180 * report count for t should not be incremented, then 181 * the sender SHOULD increment missing report count for 182 * t (according to [RFC2960] and [SCTP_STEWART_2002]). 183 */ 184 static inline int sctp_cacc_skip(struct sctp_transport *primary, 185 struct sctp_transport *transport, 186 int count_of_newacks, 187 __u32 tsn) 188 { 189 if (primary->cacc.changeover_active && 190 (sctp_cacc_skip_3_1(primary, transport, count_of_newacks) || 191 sctp_cacc_skip_3_2(primary, tsn))) 192 return 1; 193 return 0; 194 } 195 196 /* Initialize an existing sctp_outq. This does the boring stuff. 197 * You still need to define handlers if you really want to DO 198 * something with this structure... 199 */ 200 void sctp_outq_init(struct sctp_association *asoc, struct sctp_outq *q) 201 { 202 memset(q, 0, sizeof(struct sctp_outq)); 203 204 q->asoc = asoc; 205 INIT_LIST_HEAD(&q->out_chunk_list); 206 INIT_LIST_HEAD(&q->control_chunk_list); 207 INIT_LIST_HEAD(&q->retransmit); 208 INIT_LIST_HEAD(&q->sacked); 209 INIT_LIST_HEAD(&q->abandoned); 210 } 211 212 /* Free the outqueue structure and any related pending chunks. 213 */ 214 static void __sctp_outq_teardown(struct sctp_outq *q) 215 { 216 struct sctp_transport *transport; 217 struct list_head *lchunk, *temp; 218 struct sctp_chunk *chunk, *tmp; 219 220 /* Throw away unacknowledged chunks. */ 221 list_for_each_entry(transport, &q->asoc->peer.transport_addr_list, 222 transports) { 223 while ((lchunk = sctp_list_dequeue(&transport->transmitted)) != NULL) { 224 chunk = list_entry(lchunk, struct sctp_chunk, 225 transmitted_list); 226 /* Mark as part of a failed message. */ 227 sctp_chunk_fail(chunk, q->error); 228 sctp_chunk_free(chunk); 229 } 230 } 231 232 /* Throw away chunks that have been gap ACKed. */ 233 list_for_each_safe(lchunk, temp, &q->sacked) { 234 list_del_init(lchunk); 235 chunk = list_entry(lchunk, struct sctp_chunk, 236 transmitted_list); 237 sctp_chunk_fail(chunk, q->error); 238 sctp_chunk_free(chunk); 239 } 240 241 /* Throw away any chunks in the retransmit queue. */ 242 list_for_each_safe(lchunk, temp, &q->retransmit) { 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 that are in the abandoned queue. */ 251 list_for_each_safe(lchunk, temp, &q->abandoned) { 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 leftover data chunks. */ 260 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) { 261 262 /* Mark as send failure. */ 263 sctp_chunk_fail(chunk, q->error); 264 sctp_chunk_free(chunk); 265 } 266 267 /* Throw away any leftover control chunks. */ 268 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) { 269 list_del_init(&chunk->list); 270 sctp_chunk_free(chunk); 271 } 272 } 273 274 void sctp_outq_teardown(struct sctp_outq *q) 275 { 276 __sctp_outq_teardown(q); 277 sctp_outq_init(q->asoc, q); 278 } 279 280 /* Free the outqueue structure and any related pending chunks. */ 281 void sctp_outq_free(struct sctp_outq *q) 282 { 283 /* Throw away leftover chunks. */ 284 __sctp_outq_teardown(q); 285 } 286 287 /* Put a new chunk in an sctp_outq. */ 288 int sctp_outq_tail(struct sctp_outq *q, struct sctp_chunk *chunk, gfp_t gfp) 289 { 290 struct net *net = sock_net(q->asoc->base.sk); 291 int error = 0; 292 293 pr_debug("%s: outq:%p, chunk:%p[%s]\n", __func__, q, chunk, 294 chunk && chunk->chunk_hdr ? 295 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) : 296 "illegal chunk"); 297 298 /* If it is data, queue it up, otherwise, send it 299 * immediately. 300 */ 301 if (sctp_chunk_is_data(chunk)) { 302 /* Is it OK to queue data chunks? */ 303 /* From 9. Termination of Association 304 * 305 * When either endpoint performs a shutdown, the 306 * association on each peer will stop accepting new 307 * data from its user and only deliver data in queue 308 * at the time of sending or receiving the SHUTDOWN 309 * chunk. 310 */ 311 switch (q->asoc->state) { 312 case SCTP_STATE_CLOSED: 313 case SCTP_STATE_SHUTDOWN_PENDING: 314 case SCTP_STATE_SHUTDOWN_SENT: 315 case SCTP_STATE_SHUTDOWN_RECEIVED: 316 case SCTP_STATE_SHUTDOWN_ACK_SENT: 317 /* Cannot send after transport endpoint shutdown */ 318 error = -ESHUTDOWN; 319 break; 320 321 default: 322 pr_debug("%s: outqueueing: outq:%p, chunk:%p[%s])\n", 323 __func__, q, chunk, chunk && chunk->chunk_hdr ? 324 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) : 325 "illegal chunk"); 326 327 sctp_chunk_hold(chunk); 328 sctp_outq_tail_data(q, chunk); 329 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) 330 SCTP_INC_STATS(net, SCTP_MIB_OUTUNORDERCHUNKS); 331 else 332 SCTP_INC_STATS(net, SCTP_MIB_OUTORDERCHUNKS); 333 break; 334 } 335 } else { 336 list_add_tail(&chunk->list, &q->control_chunk_list); 337 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 338 } 339 340 if (error < 0) 341 return error; 342 343 if (!q->cork) 344 error = sctp_outq_flush(q, 0, gfp); 345 346 return error; 347 } 348 349 /* Insert a chunk into the sorted list based on the TSNs. The retransmit list 350 * and the abandoned list are in ascending order. 351 */ 352 static void sctp_insert_list(struct list_head *head, struct list_head *new) 353 { 354 struct list_head *pos; 355 struct sctp_chunk *nchunk, *lchunk; 356 __u32 ntsn, ltsn; 357 int done = 0; 358 359 nchunk = list_entry(new, struct sctp_chunk, transmitted_list); 360 ntsn = ntohl(nchunk->subh.data_hdr->tsn); 361 362 list_for_each(pos, head) { 363 lchunk = list_entry(pos, struct sctp_chunk, transmitted_list); 364 ltsn = ntohl(lchunk->subh.data_hdr->tsn); 365 if (TSN_lt(ntsn, ltsn)) { 366 list_add(new, pos->prev); 367 done = 1; 368 break; 369 } 370 } 371 if (!done) 372 list_add_tail(new, head); 373 } 374 375 /* Mark all the eligible packets on a transport for retransmission. */ 376 void sctp_retransmit_mark(struct sctp_outq *q, 377 struct sctp_transport *transport, 378 __u8 reason) 379 { 380 struct list_head *lchunk, *ltemp; 381 struct sctp_chunk *chunk; 382 383 /* Walk through the specified transmitted queue. */ 384 list_for_each_safe(lchunk, ltemp, &transport->transmitted) { 385 chunk = list_entry(lchunk, struct sctp_chunk, 386 transmitted_list); 387 388 /* If the chunk is abandoned, move it to abandoned list. */ 389 if (sctp_chunk_abandoned(chunk)) { 390 list_del_init(lchunk); 391 sctp_insert_list(&q->abandoned, lchunk); 392 393 /* If this chunk has not been previousely acked, 394 * stop considering it 'outstanding'. Our peer 395 * will most likely never see it since it will 396 * not be retransmitted 397 */ 398 if (!chunk->tsn_gap_acked) { 399 if (chunk->transport) 400 chunk->transport->flight_size -= 401 sctp_data_size(chunk); 402 q->outstanding_bytes -= sctp_data_size(chunk); 403 q->asoc->peer.rwnd += sctp_data_size(chunk); 404 } 405 continue; 406 } 407 408 /* If we are doing retransmission due to a timeout or pmtu 409 * discovery, only the chunks that are not yet acked should 410 * be added to the retransmit queue. 411 */ 412 if ((reason == SCTP_RTXR_FAST_RTX && 413 (chunk->fast_retransmit == SCTP_NEED_FRTX)) || 414 (reason != SCTP_RTXR_FAST_RTX && !chunk->tsn_gap_acked)) { 415 /* RFC 2960 6.2.1 Processing a Received SACK 416 * 417 * C) Any time a DATA chunk is marked for 418 * retransmission (via either T3-rtx timer expiration 419 * (Section 6.3.3) or via fast retransmit 420 * (Section 7.2.4)), add the data size of those 421 * chunks to the rwnd. 422 */ 423 q->asoc->peer.rwnd += sctp_data_size(chunk); 424 q->outstanding_bytes -= sctp_data_size(chunk); 425 if (chunk->transport) 426 transport->flight_size -= sctp_data_size(chunk); 427 428 /* sctpimpguide-05 Section 2.8.2 429 * M5) If a T3-rtx timer expires, the 430 * 'TSN.Missing.Report' of all affected TSNs is set 431 * to 0. 432 */ 433 chunk->tsn_missing_report = 0; 434 435 /* If a chunk that is being used for RTT measurement 436 * has to be retransmitted, we cannot use this chunk 437 * anymore for RTT measurements. Reset rto_pending so 438 * that a new RTT measurement is started when a new 439 * data chunk is sent. 440 */ 441 if (chunk->rtt_in_progress) { 442 chunk->rtt_in_progress = 0; 443 transport->rto_pending = 0; 444 } 445 446 chunk->resent = 1; 447 448 /* Move the chunk to the retransmit queue. The chunks 449 * on the retransmit queue are always kept in order. 450 */ 451 list_del_init(lchunk); 452 sctp_insert_list(&q->retransmit, lchunk); 453 } 454 } 455 456 pr_debug("%s: transport:%p, reason:%d, cwnd:%d, ssthresh:%d, " 457 "flight_size:%d, pba:%d\n", __func__, transport, reason, 458 transport->cwnd, transport->ssthresh, transport->flight_size, 459 transport->partial_bytes_acked); 460 } 461 462 /* Mark all the eligible packets on a transport for retransmission and force 463 * one packet out. 464 */ 465 void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport, 466 sctp_retransmit_reason_t reason) 467 { 468 struct net *net = sock_net(q->asoc->base.sk); 469 int error = 0; 470 471 switch (reason) { 472 case SCTP_RTXR_T3_RTX: 473 SCTP_INC_STATS(net, SCTP_MIB_T3_RETRANSMITS); 474 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_T3_RTX); 475 /* Update the retran path if the T3-rtx timer has expired for 476 * the current retran path. 477 */ 478 if (transport == transport->asoc->peer.retran_path) 479 sctp_assoc_update_retran_path(transport->asoc); 480 transport->asoc->rtx_data_chunks += 481 transport->asoc->unack_data; 482 break; 483 case SCTP_RTXR_FAST_RTX: 484 SCTP_INC_STATS(net, SCTP_MIB_FAST_RETRANSMITS); 485 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_FAST_RTX); 486 q->fast_rtx = 1; 487 break; 488 case SCTP_RTXR_PMTUD: 489 SCTP_INC_STATS(net, SCTP_MIB_PMTUD_RETRANSMITS); 490 break; 491 case SCTP_RTXR_T1_RTX: 492 SCTP_INC_STATS(net, SCTP_MIB_T1_RETRANSMITS); 493 transport->asoc->init_retries++; 494 break; 495 default: 496 BUG(); 497 } 498 499 sctp_retransmit_mark(q, transport, reason); 500 501 /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination, 502 * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by 503 * following the procedures outlined in C1 - C5. 504 */ 505 if (reason == SCTP_RTXR_T3_RTX) 506 sctp_generate_fwdtsn(q, q->asoc->ctsn_ack_point); 507 508 /* Flush the queues only on timeout, since fast_rtx is only 509 * triggered during sack processing and the queue 510 * will be flushed at the end. 511 */ 512 if (reason != SCTP_RTXR_FAST_RTX) 513 error = sctp_outq_flush(q, /* rtx_timeout */ 1, GFP_ATOMIC); 514 515 if (error) 516 q->asoc->base.sk->sk_err = -error; 517 } 518 519 /* 520 * Transmit DATA chunks on the retransmit queue. Upon return from 521 * sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which 522 * need to be transmitted by the caller. 523 * We assume that pkt->transport has already been set. 524 * 525 * The return value is a normal kernel error return value. 526 */ 527 static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt, 528 int rtx_timeout, int *start_timer) 529 { 530 struct list_head *lqueue; 531 struct sctp_transport *transport = pkt->transport; 532 sctp_xmit_t status; 533 struct sctp_chunk *chunk, *chunk1; 534 int fast_rtx; 535 int error = 0; 536 int timer = 0; 537 int done = 0; 538 539 lqueue = &q->retransmit; 540 fast_rtx = q->fast_rtx; 541 542 /* This loop handles time-out retransmissions, fast retransmissions, 543 * and retransmissions due to opening of whindow. 544 * 545 * RFC 2960 6.3.3 Handle T3-rtx Expiration 546 * 547 * E3) Determine how many of the earliest (i.e., lowest TSN) 548 * outstanding DATA chunks for the address for which the 549 * T3-rtx has expired will fit into a single packet, subject 550 * to the MTU constraint for the path corresponding to the 551 * destination transport address to which the retransmission 552 * is being sent (this may be different from the address for 553 * which the timer expires [see Section 6.4]). Call this value 554 * K. Bundle and retransmit those K DATA chunks in a single 555 * packet to the destination endpoint. 556 * 557 * [Just to be painfully clear, if we are retransmitting 558 * because a timeout just happened, we should send only ONE 559 * packet of retransmitted data.] 560 * 561 * For fast retransmissions we also send only ONE packet. However, 562 * if we are just flushing the queue due to open window, we'll 563 * try to send as much as possible. 564 */ 565 list_for_each_entry_safe(chunk, chunk1, lqueue, transmitted_list) { 566 /* If the chunk is abandoned, move it to abandoned list. */ 567 if (sctp_chunk_abandoned(chunk)) { 568 list_del_init(&chunk->transmitted_list); 569 sctp_insert_list(&q->abandoned, 570 &chunk->transmitted_list); 571 continue; 572 } 573 574 /* Make sure that Gap Acked TSNs are not retransmitted. A 575 * simple approach is just to move such TSNs out of the 576 * way and into a 'transmitted' queue and skip to the 577 * next chunk. 578 */ 579 if (chunk->tsn_gap_acked) { 580 list_move_tail(&chunk->transmitted_list, 581 &transport->transmitted); 582 continue; 583 } 584 585 /* If we are doing fast retransmit, ignore non-fast_rtransmit 586 * chunks 587 */ 588 if (fast_rtx && !chunk->fast_retransmit) 589 continue; 590 591 redo: 592 /* Attempt to append this chunk to the packet. */ 593 status = sctp_packet_append_chunk(pkt, chunk); 594 595 switch (status) { 596 case SCTP_XMIT_PMTU_FULL: 597 if (!pkt->has_data && !pkt->has_cookie_echo) { 598 /* If this packet did not contain DATA then 599 * retransmission did not happen, so do it 600 * again. We'll ignore the error here since 601 * control chunks are already freed so there 602 * is nothing we can do. 603 */ 604 sctp_packet_transmit(pkt, GFP_ATOMIC); 605 goto redo; 606 } 607 608 /* Send this packet. */ 609 error = sctp_packet_transmit(pkt, GFP_ATOMIC); 610 611 /* If we are retransmitting, we should only 612 * send a single packet. 613 * Otherwise, try appending this chunk again. 614 */ 615 if (rtx_timeout || fast_rtx) 616 done = 1; 617 else 618 goto redo; 619 620 /* Bundle next chunk in the next round. */ 621 break; 622 623 case SCTP_XMIT_RWND_FULL: 624 /* Send this packet. */ 625 error = sctp_packet_transmit(pkt, GFP_ATOMIC); 626 627 /* Stop sending DATA as there is no more room 628 * at the receiver. 629 */ 630 done = 1; 631 break; 632 633 case SCTP_XMIT_DELAY: 634 /* Send this packet. */ 635 error = sctp_packet_transmit(pkt, GFP_ATOMIC); 636 637 /* Stop sending DATA because of nagle delay. */ 638 done = 1; 639 break; 640 641 default: 642 /* The append was successful, so add this chunk to 643 * the transmitted list. 644 */ 645 list_move_tail(&chunk->transmitted_list, 646 &transport->transmitted); 647 648 /* Mark the chunk as ineligible for fast retransmit 649 * after it is retransmitted. 650 */ 651 if (chunk->fast_retransmit == SCTP_NEED_FRTX) 652 chunk->fast_retransmit = SCTP_DONT_FRTX; 653 654 q->asoc->stats.rtxchunks++; 655 break; 656 } 657 658 /* Set the timer if there were no errors */ 659 if (!error && !timer) 660 timer = 1; 661 662 if (done) 663 break; 664 } 665 666 /* If we are here due to a retransmit timeout or a fast 667 * retransmit and if there are any chunks left in the retransmit 668 * queue that could not fit in the PMTU sized packet, they need 669 * to be marked as ineligible for a subsequent fast retransmit. 670 */ 671 if (rtx_timeout || fast_rtx) { 672 list_for_each_entry(chunk1, lqueue, transmitted_list) { 673 if (chunk1->fast_retransmit == SCTP_NEED_FRTX) 674 chunk1->fast_retransmit = SCTP_DONT_FRTX; 675 } 676 } 677 678 *start_timer = timer; 679 680 /* Clear fast retransmit hint */ 681 if (fast_rtx) 682 q->fast_rtx = 0; 683 684 return error; 685 } 686 687 /* Cork the outqueue so queued chunks are really queued. */ 688 int sctp_outq_uncork(struct sctp_outq *q, gfp_t gfp) 689 { 690 if (q->cork) 691 q->cork = 0; 692 693 return sctp_outq_flush(q, 0, gfp); 694 } 695 696 697 /* 698 * Try to flush an outqueue. 699 * 700 * Description: Send everything in q which we legally can, subject to 701 * congestion limitations. 702 * * Note: This function can be called from multiple contexts so appropriate 703 * locking concerns must be made. Today we use the sock lock to protect 704 * this function. 705 */ 706 static int sctp_outq_flush(struct sctp_outq *q, int rtx_timeout, gfp_t gfp) 707 { 708 struct sctp_packet *packet; 709 struct sctp_packet singleton; 710 struct sctp_association *asoc = q->asoc; 711 __u16 sport = asoc->base.bind_addr.port; 712 __u16 dport = asoc->peer.port; 713 __u32 vtag = asoc->peer.i.init_tag; 714 struct sctp_transport *transport = NULL; 715 struct sctp_transport *new_transport; 716 struct sctp_chunk *chunk, *tmp; 717 sctp_xmit_t status; 718 int error = 0; 719 int start_timer = 0; 720 int one_packet = 0; 721 722 /* These transports have chunks to send. */ 723 struct list_head transport_list; 724 struct list_head *ltransport; 725 726 INIT_LIST_HEAD(&transport_list); 727 packet = NULL; 728 729 /* 730 * 6.10 Bundling 731 * ... 732 * When bundling control chunks with DATA chunks, an 733 * endpoint MUST place control chunks first in the outbound 734 * SCTP packet. The transmitter MUST transmit DATA chunks 735 * within a SCTP packet in increasing order of TSN. 736 * ... 737 */ 738 739 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) { 740 /* RFC 5061, 5.3 741 * F1) This means that until such time as the ASCONF 742 * containing the add is acknowledged, the sender MUST 743 * NOT use the new IP address as a source for ANY SCTP 744 * packet except on carrying an ASCONF Chunk. 745 */ 746 if (asoc->src_out_of_asoc_ok && 747 chunk->chunk_hdr->type != SCTP_CID_ASCONF) 748 continue; 749 750 list_del_init(&chunk->list); 751 752 /* Pick the right transport to use. */ 753 new_transport = chunk->transport; 754 755 if (!new_transport) { 756 /* 757 * If we have a prior transport pointer, see if 758 * the destination address of the chunk 759 * matches the destination address of the 760 * current transport. If not a match, then 761 * try to look up the transport with a given 762 * destination address. We do this because 763 * after processing ASCONFs, we may have new 764 * transports created. 765 */ 766 if (transport && 767 sctp_cmp_addr_exact(&chunk->dest, 768 &transport->ipaddr)) 769 new_transport = transport; 770 else 771 new_transport = sctp_assoc_lookup_paddr(asoc, 772 &chunk->dest); 773 774 /* if we still don't have a new transport, then 775 * use the current active path. 776 */ 777 if (!new_transport) 778 new_transport = asoc->peer.active_path; 779 } else if ((new_transport->state == SCTP_INACTIVE) || 780 (new_transport->state == SCTP_UNCONFIRMED) || 781 (new_transport->state == SCTP_PF)) { 782 /* If the chunk is Heartbeat or Heartbeat Ack, 783 * send it to chunk->transport, even if it's 784 * inactive. 785 * 786 * 3.3.6 Heartbeat Acknowledgement: 787 * ... 788 * A HEARTBEAT ACK is always sent to the source IP 789 * address of the IP datagram containing the 790 * HEARTBEAT chunk to which this ack is responding. 791 * ... 792 * 793 * ASCONF_ACKs also must be sent to the source. 794 */ 795 if (chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT && 796 chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT_ACK && 797 chunk->chunk_hdr->type != SCTP_CID_ASCONF_ACK) 798 new_transport = asoc->peer.active_path; 799 } 800 801 /* Are we switching transports? 802 * Take care of transport locks. 803 */ 804 if (new_transport != transport) { 805 transport = new_transport; 806 if (list_empty(&transport->send_ready)) { 807 list_add_tail(&transport->send_ready, 808 &transport_list); 809 } 810 packet = &transport->packet; 811 sctp_packet_config(packet, vtag, 812 asoc->peer.ecn_capable); 813 } 814 815 switch (chunk->chunk_hdr->type) { 816 /* 817 * 6.10 Bundling 818 * ... 819 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN 820 * COMPLETE with any other chunks. [Send them immediately.] 821 */ 822 case SCTP_CID_INIT: 823 case SCTP_CID_INIT_ACK: 824 case SCTP_CID_SHUTDOWN_COMPLETE: 825 sctp_packet_init(&singleton, transport, sport, dport); 826 sctp_packet_config(&singleton, vtag, 0); 827 sctp_packet_append_chunk(&singleton, chunk); 828 error = sctp_packet_transmit(&singleton, gfp); 829 if (error < 0) 830 return error; 831 break; 832 833 case SCTP_CID_ABORT: 834 if (sctp_test_T_bit(chunk)) { 835 packet->vtag = asoc->c.my_vtag; 836 } 837 /* The following chunks are "response" chunks, i.e. 838 * they are generated in response to something we 839 * received. If we are sending these, then we can 840 * send only 1 packet containing these chunks. 841 */ 842 case SCTP_CID_HEARTBEAT_ACK: 843 case SCTP_CID_SHUTDOWN_ACK: 844 case SCTP_CID_COOKIE_ACK: 845 case SCTP_CID_COOKIE_ECHO: 846 case SCTP_CID_ERROR: 847 case SCTP_CID_ECN_CWR: 848 case SCTP_CID_ASCONF_ACK: 849 one_packet = 1; 850 /* Fall through */ 851 852 case SCTP_CID_SACK: 853 case SCTP_CID_HEARTBEAT: 854 case SCTP_CID_SHUTDOWN: 855 case SCTP_CID_ECN_ECNE: 856 case SCTP_CID_ASCONF: 857 case SCTP_CID_FWD_TSN: 858 status = sctp_packet_transmit_chunk(packet, chunk, 859 one_packet, gfp); 860 if (status != SCTP_XMIT_OK) { 861 /* put the chunk back */ 862 list_add(&chunk->list, &q->control_chunk_list); 863 } else { 864 asoc->stats.octrlchunks++; 865 /* PR-SCTP C5) If a FORWARD TSN is sent, the 866 * sender MUST assure that at least one T3-rtx 867 * timer is running. 868 */ 869 if (chunk->chunk_hdr->type == SCTP_CID_FWD_TSN) { 870 sctp_transport_reset_t3_rtx(transport); 871 transport->last_time_sent = jiffies; 872 } 873 } 874 break; 875 876 default: 877 /* We built a chunk with an illegal type! */ 878 BUG(); 879 } 880 } 881 882 if (q->asoc->src_out_of_asoc_ok) 883 goto sctp_flush_out; 884 885 /* Is it OK to send data chunks? */ 886 switch (asoc->state) { 887 case SCTP_STATE_COOKIE_ECHOED: 888 /* Only allow bundling when this packet has a COOKIE-ECHO 889 * chunk. 890 */ 891 if (!packet || !packet->has_cookie_echo) 892 break; 893 894 /* fallthru */ 895 case SCTP_STATE_ESTABLISHED: 896 case SCTP_STATE_SHUTDOWN_PENDING: 897 case SCTP_STATE_SHUTDOWN_RECEIVED: 898 /* 899 * RFC 2960 6.1 Transmission of DATA Chunks 900 * 901 * C) When the time comes for the sender to transmit, 902 * before sending new DATA chunks, the sender MUST 903 * first transmit any outstanding DATA chunks which 904 * are marked for retransmission (limited by the 905 * current cwnd). 906 */ 907 if (!list_empty(&q->retransmit)) { 908 if (asoc->peer.retran_path->state == SCTP_UNCONFIRMED) 909 goto sctp_flush_out; 910 if (transport == asoc->peer.retran_path) 911 goto retran; 912 913 /* Switch transports & prepare the packet. */ 914 915 transport = asoc->peer.retran_path; 916 917 if (list_empty(&transport->send_ready)) { 918 list_add_tail(&transport->send_ready, 919 &transport_list); 920 } 921 922 packet = &transport->packet; 923 sctp_packet_config(packet, vtag, 924 asoc->peer.ecn_capable); 925 retran: 926 error = sctp_outq_flush_rtx(q, packet, 927 rtx_timeout, &start_timer); 928 929 if (start_timer) { 930 sctp_transport_reset_t3_rtx(transport); 931 transport->last_time_sent = jiffies; 932 } 933 934 /* This can happen on COOKIE-ECHO resend. Only 935 * one chunk can get bundled with a COOKIE-ECHO. 936 */ 937 if (packet->has_cookie_echo) 938 goto sctp_flush_out; 939 940 /* Don't send new data if there is still data 941 * waiting to retransmit. 942 */ 943 if (!list_empty(&q->retransmit)) 944 goto sctp_flush_out; 945 } 946 947 /* Apply Max.Burst limitation to the current transport in 948 * case it will be used for new data. We are going to 949 * rest it before we return, but we want to apply the limit 950 * to the currently queued data. 951 */ 952 if (transport) 953 sctp_transport_burst_limited(transport); 954 955 /* Finally, transmit new packets. */ 956 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) { 957 /* RFC 2960 6.5 Every DATA chunk MUST carry a valid 958 * stream identifier. 959 */ 960 if (chunk->sinfo.sinfo_stream >= 961 asoc->c.sinit_num_ostreams) { 962 963 /* Mark as failed send. */ 964 sctp_chunk_fail(chunk, SCTP_ERROR_INV_STRM); 965 sctp_chunk_free(chunk); 966 continue; 967 } 968 969 /* Has this chunk expired? */ 970 if (sctp_chunk_abandoned(chunk)) { 971 sctp_chunk_fail(chunk, 0); 972 sctp_chunk_free(chunk); 973 continue; 974 } 975 976 /* If there is a specified transport, use it. 977 * Otherwise, we want to use the active path. 978 */ 979 new_transport = chunk->transport; 980 if (!new_transport || 981 ((new_transport->state == SCTP_INACTIVE) || 982 (new_transport->state == SCTP_UNCONFIRMED) || 983 (new_transport->state == SCTP_PF))) 984 new_transport = asoc->peer.active_path; 985 if (new_transport->state == SCTP_UNCONFIRMED) { 986 WARN_ONCE(1, "Atempt to send packet on unconfirmed path."); 987 sctp_chunk_fail(chunk, 0); 988 sctp_chunk_free(chunk); 989 continue; 990 } 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, gfp); 1023 1024 switch (status) { 1025 case SCTP_XMIT_PMTU_FULL: 1026 case SCTP_XMIT_RWND_FULL: 1027 case SCTP_XMIT_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 1038 case SCTP_XMIT_OK: 1039 /* The sender is in the SHUTDOWN-PENDING state, 1040 * The sender MAY set the I-bit in the DATA 1041 * chunk header. 1042 */ 1043 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING) 1044 chunk->chunk_hdr->flags |= SCTP_DATA_SACK_IMM; 1045 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) 1046 asoc->stats.ouodchunks++; 1047 else 1048 asoc->stats.oodchunks++; 1049 1050 break; 1051 1052 default: 1053 BUG(); 1054 } 1055 1056 /* BUG: We assume that the sctp_packet_transmit() 1057 * call below will succeed all the time and add the 1058 * chunk to the transmitted list and restart the 1059 * timers. 1060 * It is possible that the call can fail under OOM 1061 * conditions. 1062 * 1063 * Is this really a problem? Won't this behave 1064 * like a lost TSN? 1065 */ 1066 list_add_tail(&chunk->transmitted_list, 1067 &transport->transmitted); 1068 1069 sctp_transport_reset_t3_rtx(transport); 1070 transport->last_time_sent = jiffies; 1071 1072 /* Only let one DATA chunk get bundled with a 1073 * COOKIE-ECHO chunk. 1074 */ 1075 if (packet->has_cookie_echo) 1076 goto sctp_flush_out; 1077 } 1078 break; 1079 1080 default: 1081 /* Do nothing. */ 1082 break; 1083 } 1084 1085 sctp_flush_out: 1086 1087 /* Before returning, examine all the transports touched in 1088 * this call. Right now, we bluntly force clear all the 1089 * transports. Things might change after we implement Nagle. 1090 * But such an examination is still required. 1091 * 1092 * --xguo 1093 */ 1094 while ((ltransport = sctp_list_dequeue(&transport_list)) != NULL) { 1095 struct sctp_transport *t = list_entry(ltransport, 1096 struct sctp_transport, 1097 send_ready); 1098 packet = &t->packet; 1099 if (!sctp_packet_empty(packet)) 1100 error = sctp_packet_transmit(packet, gfp); 1101 1102 /* Clear the burst limited state, if any */ 1103 sctp_transport_burst_reset(t); 1104 } 1105 1106 return error; 1107 } 1108 1109 /* Update unack_data based on the incoming SACK chunk */ 1110 static void sctp_sack_update_unack_data(struct sctp_association *assoc, 1111 struct sctp_sackhdr *sack) 1112 { 1113 sctp_sack_variable_t *frags; 1114 __u16 unack_data; 1115 int i; 1116 1117 unack_data = assoc->next_tsn - assoc->ctsn_ack_point - 1; 1118 1119 frags = sack->variable; 1120 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); i++) { 1121 unack_data -= ((ntohs(frags[i].gab.end) - 1122 ntohs(frags[i].gab.start) + 1)); 1123 } 1124 1125 assoc->unack_data = unack_data; 1126 } 1127 1128 /* This is where we REALLY process a SACK. 1129 * 1130 * Process the SACK against the outqueue. Mostly, this just frees 1131 * things off the transmitted queue. 1132 */ 1133 int sctp_outq_sack(struct sctp_outq *q, struct sctp_chunk *chunk) 1134 { 1135 struct sctp_association *asoc = q->asoc; 1136 struct sctp_sackhdr *sack = chunk->subh.sack_hdr; 1137 struct sctp_transport *transport; 1138 struct sctp_chunk *tchunk = NULL; 1139 struct list_head *lchunk, *transport_list, *temp; 1140 sctp_sack_variable_t *frags = sack->variable; 1141 __u32 sack_ctsn, ctsn, tsn; 1142 __u32 highest_tsn, highest_new_tsn; 1143 __u32 sack_a_rwnd; 1144 unsigned int outstanding; 1145 struct sctp_transport *primary = asoc->peer.primary_path; 1146 int count_of_newacks = 0; 1147 int gap_ack_blocks; 1148 u8 accum_moved = 0; 1149 1150 /* Grab the association's destination address list. */ 1151 transport_list = &asoc->peer.transport_addr_list; 1152 1153 sack_ctsn = ntohl(sack->cum_tsn_ack); 1154 gap_ack_blocks = ntohs(sack->num_gap_ack_blocks); 1155 asoc->stats.gapcnt += gap_ack_blocks; 1156 /* 1157 * SFR-CACC algorithm: 1158 * On receipt of a SACK the sender SHOULD execute the 1159 * following statements. 1160 * 1161 * 1) If the cumulative ack in the SACK passes next tsn_at_change 1162 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be 1163 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for 1164 * all destinations. 1165 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE 1166 * is set the receiver of the SACK MUST take the following actions: 1167 * 1168 * A) Initialize the cacc_saw_newack to 0 for all destination 1169 * addresses. 1170 * 1171 * Only bother if changeover_active is set. Otherwise, this is 1172 * totally suboptimal to do on every SACK. 1173 */ 1174 if (primary->cacc.changeover_active) { 1175 u8 clear_cycling = 0; 1176 1177 if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) { 1178 primary->cacc.changeover_active = 0; 1179 clear_cycling = 1; 1180 } 1181 1182 if (clear_cycling || gap_ack_blocks) { 1183 list_for_each_entry(transport, transport_list, 1184 transports) { 1185 if (clear_cycling) 1186 transport->cacc.cycling_changeover = 0; 1187 if (gap_ack_blocks) 1188 transport->cacc.cacc_saw_newack = 0; 1189 } 1190 } 1191 } 1192 1193 /* Get the highest TSN in the sack. */ 1194 highest_tsn = sack_ctsn; 1195 if (gap_ack_blocks) 1196 highest_tsn += ntohs(frags[gap_ack_blocks - 1].gab.end); 1197 1198 if (TSN_lt(asoc->highest_sacked, highest_tsn)) 1199 asoc->highest_sacked = highest_tsn; 1200 1201 highest_new_tsn = sack_ctsn; 1202 1203 /* Run through the retransmit queue. Credit bytes received 1204 * and free those chunks that we can. 1205 */ 1206 sctp_check_transmitted(q, &q->retransmit, NULL, NULL, sack, &highest_new_tsn); 1207 1208 /* Run through the transmitted queue. 1209 * Credit bytes received and free those chunks which we can. 1210 * 1211 * This is a MASSIVE candidate for optimization. 1212 */ 1213 list_for_each_entry(transport, transport_list, transports) { 1214 sctp_check_transmitted(q, &transport->transmitted, 1215 transport, &chunk->source, sack, 1216 &highest_new_tsn); 1217 /* 1218 * SFR-CACC algorithm: 1219 * C) Let count_of_newacks be the number of 1220 * destinations for which cacc_saw_newack is set. 1221 */ 1222 if (transport->cacc.cacc_saw_newack) 1223 count_of_newacks++; 1224 } 1225 1226 /* Move the Cumulative TSN Ack Point if appropriate. */ 1227 if (TSN_lt(asoc->ctsn_ack_point, sack_ctsn)) { 1228 asoc->ctsn_ack_point = sack_ctsn; 1229 accum_moved = 1; 1230 } 1231 1232 if (gap_ack_blocks) { 1233 1234 if (asoc->fast_recovery && accum_moved) 1235 highest_new_tsn = highest_tsn; 1236 1237 list_for_each_entry(transport, transport_list, transports) 1238 sctp_mark_missing(q, &transport->transmitted, transport, 1239 highest_new_tsn, count_of_newacks); 1240 } 1241 1242 /* Update unack_data field in the assoc. */ 1243 sctp_sack_update_unack_data(asoc, sack); 1244 1245 ctsn = asoc->ctsn_ack_point; 1246 1247 /* Throw away stuff rotting on the sack queue. */ 1248 list_for_each_safe(lchunk, temp, &q->sacked) { 1249 tchunk = list_entry(lchunk, struct sctp_chunk, 1250 transmitted_list); 1251 tsn = ntohl(tchunk->subh.data_hdr->tsn); 1252 if (TSN_lte(tsn, ctsn)) { 1253 list_del_init(&tchunk->transmitted_list); 1254 sctp_chunk_free(tchunk); 1255 } 1256 } 1257 1258 /* ii) Set rwnd equal to the newly received a_rwnd minus the 1259 * number of bytes still outstanding after processing the 1260 * Cumulative TSN Ack and the Gap Ack Blocks. 1261 */ 1262 1263 sack_a_rwnd = ntohl(sack->a_rwnd); 1264 asoc->peer.zero_window_announced = !sack_a_rwnd; 1265 outstanding = q->outstanding_bytes; 1266 1267 if (outstanding < sack_a_rwnd) 1268 sack_a_rwnd -= outstanding; 1269 else 1270 sack_a_rwnd = 0; 1271 1272 asoc->peer.rwnd = sack_a_rwnd; 1273 1274 sctp_generate_fwdtsn(q, sack_ctsn); 1275 1276 pr_debug("%s: sack cumulative tsn ack:0x%x\n", __func__, sack_ctsn); 1277 pr_debug("%s: cumulative tsn ack of assoc:%p is 0x%x, " 1278 "advertised peer ack point:0x%x\n", __func__, asoc, ctsn, 1279 asoc->adv_peer_ack_point); 1280 1281 return sctp_outq_is_empty(q); 1282 } 1283 1284 /* Is the outqueue empty? 1285 * The queue is empty when we have not pending data, no in-flight data 1286 * and nothing pending retransmissions. 1287 */ 1288 int sctp_outq_is_empty(const struct sctp_outq *q) 1289 { 1290 return q->out_qlen == 0 && q->outstanding_bytes == 0 && 1291 list_empty(&q->retransmit); 1292 } 1293 1294 /******************************************************************** 1295 * 2nd Level Abstractions 1296 ********************************************************************/ 1297 1298 /* Go through a transport's transmitted list or the association's retransmit 1299 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked. 1300 * The retransmit list will not have an associated transport. 1301 * 1302 * I added coherent debug information output. --xguo 1303 * 1304 * Instead of printing 'sacked' or 'kept' for each TSN on the 1305 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5. 1306 * KEPT TSN6-TSN7, etc. 1307 */ 1308 static void sctp_check_transmitted(struct sctp_outq *q, 1309 struct list_head *transmitted_queue, 1310 struct sctp_transport *transport, 1311 union sctp_addr *saddr, 1312 struct sctp_sackhdr *sack, 1313 __u32 *highest_new_tsn_in_sack) 1314 { 1315 struct list_head *lchunk; 1316 struct sctp_chunk *tchunk; 1317 struct list_head tlist; 1318 __u32 tsn; 1319 __u32 sack_ctsn; 1320 __u32 rtt; 1321 __u8 restart_timer = 0; 1322 int bytes_acked = 0; 1323 int migrate_bytes = 0; 1324 bool forward_progress = false; 1325 1326 sack_ctsn = ntohl(sack->cum_tsn_ack); 1327 1328 INIT_LIST_HEAD(&tlist); 1329 1330 /* The while loop will skip empty transmitted queues. */ 1331 while (NULL != (lchunk = sctp_list_dequeue(transmitted_queue))) { 1332 tchunk = list_entry(lchunk, struct sctp_chunk, 1333 transmitted_list); 1334 1335 if (sctp_chunk_abandoned(tchunk)) { 1336 /* Move the chunk to abandoned list. */ 1337 sctp_insert_list(&q->abandoned, lchunk); 1338 1339 /* If this chunk has not been acked, stop 1340 * considering it as 'outstanding'. 1341 */ 1342 if (!tchunk->tsn_gap_acked) { 1343 if (tchunk->transport) 1344 tchunk->transport->flight_size -= 1345 sctp_data_size(tchunk); 1346 q->outstanding_bytes -= sctp_data_size(tchunk); 1347 } 1348 continue; 1349 } 1350 1351 tsn = ntohl(tchunk->subh.data_hdr->tsn); 1352 if (sctp_acked(sack, tsn)) { 1353 /* If this queue is the retransmit queue, the 1354 * retransmit timer has already reclaimed 1355 * the outstanding bytes for this chunk, so only 1356 * count bytes associated with a transport. 1357 */ 1358 if (transport) { 1359 /* If this chunk is being used for RTT 1360 * measurement, calculate the RTT and update 1361 * the RTO using this value. 1362 * 1363 * 6.3.1 C5) Karn's algorithm: RTT measurements 1364 * MUST NOT be made using packets that were 1365 * retransmitted (and thus for which it is 1366 * ambiguous whether the reply was for the 1367 * first instance of the packet or a later 1368 * instance). 1369 */ 1370 if (!tchunk->tsn_gap_acked && 1371 !tchunk->resent && 1372 tchunk->rtt_in_progress) { 1373 tchunk->rtt_in_progress = 0; 1374 rtt = jiffies - tchunk->sent_at; 1375 sctp_transport_update_rto(transport, 1376 rtt); 1377 } 1378 } 1379 1380 /* If the chunk hasn't been marked as ACKED, 1381 * mark it and account bytes_acked if the 1382 * chunk had a valid transport (it will not 1383 * have a transport if ASCONF had deleted it 1384 * while DATA was outstanding). 1385 */ 1386 if (!tchunk->tsn_gap_acked) { 1387 tchunk->tsn_gap_acked = 1; 1388 if (TSN_lt(*highest_new_tsn_in_sack, tsn)) 1389 *highest_new_tsn_in_sack = tsn; 1390 bytes_acked += sctp_data_size(tchunk); 1391 if (!tchunk->transport) 1392 migrate_bytes += sctp_data_size(tchunk); 1393 forward_progress = true; 1394 } 1395 1396 if (TSN_lte(tsn, sack_ctsn)) { 1397 /* RFC 2960 6.3.2 Retransmission Timer Rules 1398 * 1399 * R3) Whenever a SACK is received 1400 * that acknowledges the DATA chunk 1401 * with the earliest outstanding TSN 1402 * for that address, restart T3-rtx 1403 * timer for that address with its 1404 * current RTO. 1405 */ 1406 restart_timer = 1; 1407 forward_progress = true; 1408 1409 if (!tchunk->tsn_gap_acked) { 1410 /* 1411 * SFR-CACC algorithm: 1412 * 2) If the SACK contains gap acks 1413 * and the flag CHANGEOVER_ACTIVE is 1414 * set the receiver of the SACK MUST 1415 * take the following action: 1416 * 1417 * B) For each TSN t being acked that 1418 * has not been acked in any SACK so 1419 * far, set cacc_saw_newack to 1 for 1420 * the destination that the TSN was 1421 * sent to. 1422 */ 1423 if (transport && 1424 sack->num_gap_ack_blocks && 1425 q->asoc->peer.primary_path->cacc. 1426 changeover_active) 1427 transport->cacc.cacc_saw_newack 1428 = 1; 1429 } 1430 1431 list_add_tail(&tchunk->transmitted_list, 1432 &q->sacked); 1433 } else { 1434 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2 1435 * M2) Each time a SACK arrives reporting 1436 * 'Stray DATA chunk(s)' record the highest TSN 1437 * reported as newly acknowledged, call this 1438 * value 'HighestTSNinSack'. A newly 1439 * acknowledged DATA chunk is one not 1440 * previously acknowledged in a SACK. 1441 * 1442 * When the SCTP sender of data receives a SACK 1443 * chunk that acknowledges, for the first time, 1444 * the receipt of a DATA chunk, all the still 1445 * unacknowledged DATA chunks whose TSN is 1446 * older than that newly acknowledged DATA 1447 * chunk, are qualified as 'Stray DATA chunks'. 1448 */ 1449 list_add_tail(lchunk, &tlist); 1450 } 1451 } else { 1452 if (tchunk->tsn_gap_acked) { 1453 pr_debug("%s: receiver reneged on data TSN:0x%x\n", 1454 __func__, tsn); 1455 1456 tchunk->tsn_gap_acked = 0; 1457 1458 if (tchunk->transport) 1459 bytes_acked -= sctp_data_size(tchunk); 1460 1461 /* RFC 2960 6.3.2 Retransmission Timer Rules 1462 * 1463 * R4) Whenever a SACK is received missing a 1464 * TSN that was previously acknowledged via a 1465 * Gap Ack Block, start T3-rtx for the 1466 * destination address to which the DATA 1467 * chunk was originally 1468 * transmitted if it is not already running. 1469 */ 1470 restart_timer = 1; 1471 } 1472 1473 list_add_tail(lchunk, &tlist); 1474 } 1475 } 1476 1477 if (transport) { 1478 if (bytes_acked) { 1479 struct sctp_association *asoc = transport->asoc; 1480 1481 /* We may have counted DATA that was migrated 1482 * to this transport due to DEL-IP operation. 1483 * Subtract those bytes, since the were never 1484 * send on this transport and shouldn't be 1485 * credited to this transport. 1486 */ 1487 bytes_acked -= migrate_bytes; 1488 1489 /* 8.2. When an outstanding TSN is acknowledged, 1490 * the endpoint shall clear the error counter of 1491 * the destination transport address to which the 1492 * DATA chunk was last sent. 1493 * The association's overall error counter is 1494 * also cleared. 1495 */ 1496 transport->error_count = 0; 1497 transport->asoc->overall_error_count = 0; 1498 forward_progress = true; 1499 1500 /* 1501 * While in SHUTDOWN PENDING, we may have started 1502 * the T5 shutdown guard timer after reaching the 1503 * retransmission limit. Stop that timer as soon 1504 * as the receiver acknowledged any data. 1505 */ 1506 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING && 1507 del_timer(&asoc->timers 1508 [SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD])) 1509 sctp_association_put(asoc); 1510 1511 /* Mark the destination transport address as 1512 * active if it is not so marked. 1513 */ 1514 if ((transport->state == SCTP_INACTIVE || 1515 transport->state == SCTP_UNCONFIRMED) && 1516 sctp_cmp_addr_exact(&transport->ipaddr, saddr)) { 1517 sctp_assoc_control_transport( 1518 transport->asoc, 1519 transport, 1520 SCTP_TRANSPORT_UP, 1521 SCTP_RECEIVED_SACK); 1522 } 1523 1524 sctp_transport_raise_cwnd(transport, sack_ctsn, 1525 bytes_acked); 1526 1527 transport->flight_size -= bytes_acked; 1528 if (transport->flight_size == 0) 1529 transport->partial_bytes_acked = 0; 1530 q->outstanding_bytes -= bytes_acked + migrate_bytes; 1531 } else { 1532 /* RFC 2960 6.1, sctpimpguide-06 2.15.2 1533 * When a sender is doing zero window probing, it 1534 * should not timeout the association if it continues 1535 * to receive new packets from the receiver. The 1536 * reason is that the receiver MAY keep its window 1537 * closed for an indefinite time. 1538 * A sender is doing zero window probing when the 1539 * receiver's advertised window is zero, and there is 1540 * only one data chunk in flight to the receiver. 1541 * 1542 * Allow the association to timeout while in SHUTDOWN 1543 * PENDING or SHUTDOWN RECEIVED in case the receiver 1544 * stays in zero window mode forever. 1545 */ 1546 if (!q->asoc->peer.rwnd && 1547 !list_empty(&tlist) && 1548 (sack_ctsn+2 == q->asoc->next_tsn) && 1549 q->asoc->state < SCTP_STATE_SHUTDOWN_PENDING) { 1550 pr_debug("%s: sack received for zero window " 1551 "probe:%u\n", __func__, sack_ctsn); 1552 1553 q->asoc->overall_error_count = 0; 1554 transport->error_count = 0; 1555 } 1556 } 1557 1558 /* RFC 2960 6.3.2 Retransmission Timer Rules 1559 * 1560 * R2) Whenever all outstanding data sent to an address have 1561 * been acknowledged, turn off the T3-rtx timer of that 1562 * address. 1563 */ 1564 if (!transport->flight_size) { 1565 if (del_timer(&transport->T3_rtx_timer)) 1566 sctp_transport_put(transport); 1567 } else if (restart_timer) { 1568 if (!mod_timer(&transport->T3_rtx_timer, 1569 jiffies + transport->rto)) 1570 sctp_transport_hold(transport); 1571 } 1572 1573 if (forward_progress) { 1574 if (transport->dst) 1575 dst_confirm(transport->dst); 1576 } 1577 } 1578 1579 list_splice(&tlist, transmitted_queue); 1580 } 1581 1582 /* Mark chunks as missing and consequently may get retransmitted. */ 1583 static void sctp_mark_missing(struct sctp_outq *q, 1584 struct list_head *transmitted_queue, 1585 struct sctp_transport *transport, 1586 __u32 highest_new_tsn_in_sack, 1587 int count_of_newacks) 1588 { 1589 struct sctp_chunk *chunk; 1590 __u32 tsn; 1591 char do_fast_retransmit = 0; 1592 struct sctp_association *asoc = q->asoc; 1593 struct sctp_transport *primary = asoc->peer.primary_path; 1594 1595 list_for_each_entry(chunk, transmitted_queue, transmitted_list) { 1596 1597 tsn = ntohl(chunk->subh.data_hdr->tsn); 1598 1599 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all 1600 * 'Unacknowledged TSN's', if the TSN number of an 1601 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack' 1602 * value, increment the 'TSN.Missing.Report' count on that 1603 * chunk if it has NOT been fast retransmitted or marked for 1604 * fast retransmit already. 1605 */ 1606 if (chunk->fast_retransmit == SCTP_CAN_FRTX && 1607 !chunk->tsn_gap_acked && 1608 TSN_lt(tsn, highest_new_tsn_in_sack)) { 1609 1610 /* SFR-CACC may require us to skip marking 1611 * this chunk as missing. 1612 */ 1613 if (!transport || !sctp_cacc_skip(primary, 1614 chunk->transport, 1615 count_of_newacks, tsn)) { 1616 chunk->tsn_missing_report++; 1617 1618 pr_debug("%s: tsn:0x%x missing counter:%d\n", 1619 __func__, tsn, chunk->tsn_missing_report); 1620 } 1621 } 1622 /* 1623 * M4) If any DATA chunk is found to have a 1624 * 'TSN.Missing.Report' 1625 * value larger than or equal to 3, mark that chunk for 1626 * retransmission and start the fast retransmit procedure. 1627 */ 1628 1629 if (chunk->tsn_missing_report >= 3) { 1630 chunk->fast_retransmit = SCTP_NEED_FRTX; 1631 do_fast_retransmit = 1; 1632 } 1633 } 1634 1635 if (transport) { 1636 if (do_fast_retransmit) 1637 sctp_retransmit(q, transport, SCTP_RTXR_FAST_RTX); 1638 1639 pr_debug("%s: transport:%p, cwnd:%d, ssthresh:%d, " 1640 "flight_size:%d, pba:%d\n", __func__, transport, 1641 transport->cwnd, transport->ssthresh, 1642 transport->flight_size, transport->partial_bytes_acked); 1643 } 1644 } 1645 1646 /* Is the given TSN acked by this packet? */ 1647 static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn) 1648 { 1649 int i; 1650 sctp_sack_variable_t *frags; 1651 __u16 gap; 1652 __u32 ctsn = ntohl(sack->cum_tsn_ack); 1653 1654 if (TSN_lte(tsn, ctsn)) 1655 goto pass; 1656 1657 /* 3.3.4 Selective Acknowledgement (SACK) (3): 1658 * 1659 * Gap Ack Blocks: 1660 * These fields contain the Gap Ack Blocks. They are repeated 1661 * for each Gap Ack Block up to the number of Gap Ack Blocks 1662 * defined in the Number of Gap Ack Blocks field. All DATA 1663 * chunks with TSNs greater than or equal to (Cumulative TSN 1664 * Ack + Gap Ack Block Start) and less than or equal to 1665 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack 1666 * Block are assumed to have been received correctly. 1667 */ 1668 1669 frags = sack->variable; 1670 gap = tsn - ctsn; 1671 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); ++i) { 1672 if (TSN_lte(ntohs(frags[i].gab.start), gap) && 1673 TSN_lte(gap, ntohs(frags[i].gab.end))) 1674 goto pass; 1675 } 1676 1677 return 0; 1678 pass: 1679 return 1; 1680 } 1681 1682 static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip *skiplist, 1683 int nskips, __be16 stream) 1684 { 1685 int i; 1686 1687 for (i = 0; i < nskips; i++) { 1688 if (skiplist[i].stream == stream) 1689 return i; 1690 } 1691 return i; 1692 } 1693 1694 /* Create and add a fwdtsn chunk to the outq's control queue if needed. */ 1695 static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 ctsn) 1696 { 1697 struct sctp_association *asoc = q->asoc; 1698 struct sctp_chunk *ftsn_chunk = NULL; 1699 struct sctp_fwdtsn_skip ftsn_skip_arr[10]; 1700 int nskips = 0; 1701 int skip_pos = 0; 1702 __u32 tsn; 1703 struct sctp_chunk *chunk; 1704 struct list_head *lchunk, *temp; 1705 1706 if (!asoc->peer.prsctp_capable) 1707 return; 1708 1709 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the 1710 * received SACK. 1711 * 1712 * If (Advanced.Peer.Ack.Point < SackCumAck), then update 1713 * Advanced.Peer.Ack.Point to be equal to SackCumAck. 1714 */ 1715 if (TSN_lt(asoc->adv_peer_ack_point, ctsn)) 1716 asoc->adv_peer_ack_point = ctsn; 1717 1718 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point" 1719 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as 1720 * the chunk next in the out-queue space is marked as "abandoned" as 1721 * shown in the following example: 1722 * 1723 * Assuming that a SACK arrived with the Cumulative TSN ACK 102 1724 * and the Advanced.Peer.Ack.Point is updated to this value: 1725 * 1726 * out-queue at the end of ==> out-queue after Adv.Ack.Point 1727 * normal SACK processing local advancement 1728 * ... ... 1729 * Adv.Ack.Pt-> 102 acked 102 acked 1730 * 103 abandoned 103 abandoned 1731 * 104 abandoned Adv.Ack.P-> 104 abandoned 1732 * 105 105 1733 * 106 acked 106 acked 1734 * ... ... 1735 * 1736 * In this example, the data sender successfully advanced the 1737 * "Advanced.Peer.Ack.Point" from 102 to 104 locally. 1738 */ 1739 list_for_each_safe(lchunk, temp, &q->abandoned) { 1740 chunk = list_entry(lchunk, struct sctp_chunk, 1741 transmitted_list); 1742 tsn = ntohl(chunk->subh.data_hdr->tsn); 1743 1744 /* Remove any chunks in the abandoned queue that are acked by 1745 * the ctsn. 1746 */ 1747 if (TSN_lte(tsn, ctsn)) { 1748 list_del_init(lchunk); 1749 sctp_chunk_free(chunk); 1750 } else { 1751 if (TSN_lte(tsn, asoc->adv_peer_ack_point+1)) { 1752 asoc->adv_peer_ack_point = tsn; 1753 if (chunk->chunk_hdr->flags & 1754 SCTP_DATA_UNORDERED) 1755 continue; 1756 skip_pos = sctp_get_skip_pos(&ftsn_skip_arr[0], 1757 nskips, 1758 chunk->subh.data_hdr->stream); 1759 ftsn_skip_arr[skip_pos].stream = 1760 chunk->subh.data_hdr->stream; 1761 ftsn_skip_arr[skip_pos].ssn = 1762 chunk->subh.data_hdr->ssn; 1763 if (skip_pos == nskips) 1764 nskips++; 1765 if (nskips == 10) 1766 break; 1767 } else 1768 break; 1769 } 1770 } 1771 1772 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point" 1773 * is greater than the Cumulative TSN ACK carried in the received 1774 * SACK, the data sender MUST send the data receiver a FORWARD TSN 1775 * chunk containing the latest value of the 1776 * "Advanced.Peer.Ack.Point". 1777 * 1778 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD 1779 * list each stream and sequence number in the forwarded TSN. This 1780 * information will enable the receiver to easily find any 1781 * stranded TSN's waiting on stream reorder queues. Each stream 1782 * SHOULD only be reported once; this means that if multiple 1783 * abandoned messages occur in the same stream then only the 1784 * highest abandoned stream sequence number is reported. If the 1785 * total size of the FORWARD TSN does NOT fit in a single MTU then 1786 * the sender of the FORWARD TSN SHOULD lower the 1787 * Advanced.Peer.Ack.Point to the last TSN that will fit in a 1788 * single MTU. 1789 */ 1790 if (asoc->adv_peer_ack_point > ctsn) 1791 ftsn_chunk = sctp_make_fwdtsn(asoc, asoc->adv_peer_ack_point, 1792 nskips, &ftsn_skip_arr[0]); 1793 1794 if (ftsn_chunk) { 1795 list_add_tail(&ftsn_chunk->list, &q->control_chunk_list); 1796 SCTP_INC_STATS(sock_net(asoc->base.sk), SCTP_MIB_OUTCTRLCHUNKS); 1797 } 1798 } 1799