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 void 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 void 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); 291 292 pr_debug("%s: outq:%p, chunk:%p[%s]\n", __func__, q, chunk, 293 chunk && chunk->chunk_hdr ? 294 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) : 295 "illegal chunk"); 296 297 /* If it is data, queue it up, otherwise, send it 298 * immediately. 299 */ 300 if (sctp_chunk_is_data(chunk)) { 301 pr_debug("%s: outqueueing: outq:%p, chunk:%p[%s])\n", 302 __func__, q, chunk, chunk && chunk->chunk_hdr ? 303 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) : 304 "illegal chunk"); 305 306 sctp_outq_tail_data(q, chunk); 307 if (chunk->asoc->peer.prsctp_capable && 308 SCTP_PR_PRIO_ENABLED(chunk->sinfo.sinfo_flags)) 309 chunk->asoc->sent_cnt_removable++; 310 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) 311 SCTP_INC_STATS(net, SCTP_MIB_OUTUNORDERCHUNKS); 312 else 313 SCTP_INC_STATS(net, SCTP_MIB_OUTORDERCHUNKS); 314 } else { 315 list_add_tail(&chunk->list, &q->control_chunk_list); 316 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 317 } 318 319 if (!q->cork) 320 sctp_outq_flush(q, 0, gfp); 321 } 322 323 /* Insert a chunk into the sorted list based on the TSNs. The retransmit list 324 * and the abandoned list are in ascending order. 325 */ 326 static void sctp_insert_list(struct list_head *head, struct list_head *new) 327 { 328 struct list_head *pos; 329 struct sctp_chunk *nchunk, *lchunk; 330 __u32 ntsn, ltsn; 331 int done = 0; 332 333 nchunk = list_entry(new, struct sctp_chunk, transmitted_list); 334 ntsn = ntohl(nchunk->subh.data_hdr->tsn); 335 336 list_for_each(pos, head) { 337 lchunk = list_entry(pos, struct sctp_chunk, transmitted_list); 338 ltsn = ntohl(lchunk->subh.data_hdr->tsn); 339 if (TSN_lt(ntsn, ltsn)) { 340 list_add(new, pos->prev); 341 done = 1; 342 break; 343 } 344 } 345 if (!done) 346 list_add_tail(new, head); 347 } 348 349 static int sctp_prsctp_prune_sent(struct sctp_association *asoc, 350 struct sctp_sndrcvinfo *sinfo, 351 struct list_head *queue, int msg_len) 352 { 353 struct sctp_chunk *chk, *temp; 354 355 list_for_each_entry_safe(chk, temp, queue, transmitted_list) { 356 if (!SCTP_PR_PRIO_ENABLED(chk->sinfo.sinfo_flags) || 357 chk->sinfo.sinfo_timetolive <= sinfo->sinfo_timetolive) 358 continue; 359 360 list_del_init(&chk->transmitted_list); 361 sctp_insert_list(&asoc->outqueue.abandoned, 362 &chk->transmitted_list); 363 364 asoc->sent_cnt_removable--; 365 asoc->abandoned_sent[SCTP_PR_INDEX(PRIO)]++; 366 367 if (!chk->tsn_gap_acked) { 368 if (chk->transport) 369 chk->transport->flight_size -= 370 sctp_data_size(chk); 371 asoc->outqueue.outstanding_bytes -= sctp_data_size(chk); 372 } 373 374 msg_len -= SCTP_DATA_SNDSIZE(chk) + 375 sizeof(struct sk_buff) + 376 sizeof(struct sctp_chunk); 377 if (msg_len <= 0) 378 break; 379 } 380 381 return msg_len; 382 } 383 384 static int sctp_prsctp_prune_unsent(struct sctp_association *asoc, 385 struct sctp_sndrcvinfo *sinfo, int msg_len) 386 { 387 struct sctp_outq *q = &asoc->outqueue; 388 struct sctp_chunk *chk, *temp; 389 390 list_for_each_entry_safe(chk, temp, &q->out_chunk_list, list) { 391 if (!SCTP_PR_PRIO_ENABLED(chk->sinfo.sinfo_flags) || 392 chk->sinfo.sinfo_timetolive <= sinfo->sinfo_timetolive) 393 continue; 394 395 list_del_init(&chk->list); 396 q->out_qlen -= chk->skb->len; 397 asoc->sent_cnt_removable--; 398 asoc->abandoned_unsent[SCTP_PR_INDEX(PRIO)]++; 399 400 msg_len -= SCTP_DATA_SNDSIZE(chk) + 401 sizeof(struct sk_buff) + 402 sizeof(struct sctp_chunk); 403 sctp_chunk_free(chk); 404 if (msg_len <= 0) 405 break; 406 } 407 408 return msg_len; 409 } 410 411 /* Abandon the chunks according their priorities */ 412 void sctp_prsctp_prune(struct sctp_association *asoc, 413 struct sctp_sndrcvinfo *sinfo, int msg_len) 414 { 415 struct sctp_transport *transport; 416 417 if (!asoc->peer.prsctp_capable || !asoc->sent_cnt_removable) 418 return; 419 420 msg_len = sctp_prsctp_prune_sent(asoc, sinfo, 421 &asoc->outqueue.retransmit, 422 msg_len); 423 if (msg_len <= 0) 424 return; 425 426 list_for_each_entry(transport, &asoc->peer.transport_addr_list, 427 transports) { 428 msg_len = sctp_prsctp_prune_sent(asoc, sinfo, 429 &transport->transmitted, 430 msg_len); 431 if (msg_len <= 0) 432 return; 433 } 434 435 sctp_prsctp_prune_unsent(asoc, sinfo, msg_len); 436 } 437 438 /* Mark all the eligible packets on a transport for retransmission. */ 439 void sctp_retransmit_mark(struct sctp_outq *q, 440 struct sctp_transport *transport, 441 __u8 reason) 442 { 443 struct list_head *lchunk, *ltemp; 444 struct sctp_chunk *chunk; 445 446 /* Walk through the specified transmitted queue. */ 447 list_for_each_safe(lchunk, ltemp, &transport->transmitted) { 448 chunk = list_entry(lchunk, struct sctp_chunk, 449 transmitted_list); 450 451 /* If the chunk is abandoned, move it to abandoned list. */ 452 if (sctp_chunk_abandoned(chunk)) { 453 list_del_init(lchunk); 454 sctp_insert_list(&q->abandoned, lchunk); 455 456 /* If this chunk has not been previousely acked, 457 * stop considering it 'outstanding'. Our peer 458 * will most likely never see it since it will 459 * not be retransmitted 460 */ 461 if (!chunk->tsn_gap_acked) { 462 if (chunk->transport) 463 chunk->transport->flight_size -= 464 sctp_data_size(chunk); 465 q->outstanding_bytes -= sctp_data_size(chunk); 466 q->asoc->peer.rwnd += sctp_data_size(chunk); 467 } 468 continue; 469 } 470 471 /* If we are doing retransmission due to a timeout or pmtu 472 * discovery, only the chunks that are not yet acked should 473 * be added to the retransmit queue. 474 */ 475 if ((reason == SCTP_RTXR_FAST_RTX && 476 (chunk->fast_retransmit == SCTP_NEED_FRTX)) || 477 (reason != SCTP_RTXR_FAST_RTX && !chunk->tsn_gap_acked)) { 478 /* RFC 2960 6.2.1 Processing a Received SACK 479 * 480 * C) Any time a DATA chunk is marked for 481 * retransmission (via either T3-rtx timer expiration 482 * (Section 6.3.3) or via fast retransmit 483 * (Section 7.2.4)), add the data size of those 484 * chunks to the rwnd. 485 */ 486 q->asoc->peer.rwnd += sctp_data_size(chunk); 487 q->outstanding_bytes -= sctp_data_size(chunk); 488 if (chunk->transport) 489 transport->flight_size -= sctp_data_size(chunk); 490 491 /* sctpimpguide-05 Section 2.8.2 492 * M5) If a T3-rtx timer expires, the 493 * 'TSN.Missing.Report' of all affected TSNs is set 494 * to 0. 495 */ 496 chunk->tsn_missing_report = 0; 497 498 /* If a chunk that is being used for RTT measurement 499 * has to be retransmitted, we cannot use this chunk 500 * anymore for RTT measurements. Reset rto_pending so 501 * that a new RTT measurement is started when a new 502 * data chunk is sent. 503 */ 504 if (chunk->rtt_in_progress) { 505 chunk->rtt_in_progress = 0; 506 transport->rto_pending = 0; 507 } 508 509 /* Move the chunk to the retransmit queue. The chunks 510 * on the retransmit queue are always kept in order. 511 */ 512 list_del_init(lchunk); 513 sctp_insert_list(&q->retransmit, lchunk); 514 } 515 } 516 517 pr_debug("%s: transport:%p, reason:%d, cwnd:%d, ssthresh:%d, " 518 "flight_size:%d, pba:%d\n", __func__, transport, reason, 519 transport->cwnd, transport->ssthresh, transport->flight_size, 520 transport->partial_bytes_acked); 521 } 522 523 /* Mark all the eligible packets on a transport for retransmission and force 524 * one packet out. 525 */ 526 void sctp_retransmit(struct sctp_outq *q, struct sctp_transport *transport, 527 sctp_retransmit_reason_t reason) 528 { 529 struct net *net = sock_net(q->asoc->base.sk); 530 531 switch (reason) { 532 case SCTP_RTXR_T3_RTX: 533 SCTP_INC_STATS(net, SCTP_MIB_T3_RETRANSMITS); 534 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_T3_RTX); 535 /* Update the retran path if the T3-rtx timer has expired for 536 * the current retran path. 537 */ 538 if (transport == transport->asoc->peer.retran_path) 539 sctp_assoc_update_retran_path(transport->asoc); 540 transport->asoc->rtx_data_chunks += 541 transport->asoc->unack_data; 542 break; 543 case SCTP_RTXR_FAST_RTX: 544 SCTP_INC_STATS(net, SCTP_MIB_FAST_RETRANSMITS); 545 sctp_transport_lower_cwnd(transport, SCTP_LOWER_CWND_FAST_RTX); 546 q->fast_rtx = 1; 547 break; 548 case SCTP_RTXR_PMTUD: 549 SCTP_INC_STATS(net, SCTP_MIB_PMTUD_RETRANSMITS); 550 break; 551 case SCTP_RTXR_T1_RTX: 552 SCTP_INC_STATS(net, SCTP_MIB_T1_RETRANSMITS); 553 transport->asoc->init_retries++; 554 break; 555 default: 556 BUG(); 557 } 558 559 sctp_retransmit_mark(q, transport, reason); 560 561 /* PR-SCTP A5) Any time the T3-rtx timer expires, on any destination, 562 * the sender SHOULD try to advance the "Advanced.Peer.Ack.Point" by 563 * following the procedures outlined in C1 - C5. 564 */ 565 if (reason == SCTP_RTXR_T3_RTX) 566 sctp_generate_fwdtsn(q, q->asoc->ctsn_ack_point); 567 568 /* Flush the queues only on timeout, since fast_rtx is only 569 * triggered during sack processing and the queue 570 * will be flushed at the end. 571 */ 572 if (reason != SCTP_RTXR_FAST_RTX) 573 sctp_outq_flush(q, /* rtx_timeout */ 1, GFP_ATOMIC); 574 } 575 576 /* 577 * Transmit DATA chunks on the retransmit queue. Upon return from 578 * sctp_outq_flush_rtx() the packet 'pkt' may contain chunks which 579 * need to be transmitted by the caller. 580 * We assume that pkt->transport has already been set. 581 * 582 * The return value is a normal kernel error return value. 583 */ 584 static int sctp_outq_flush_rtx(struct sctp_outq *q, struct sctp_packet *pkt, 585 int rtx_timeout, int *start_timer) 586 { 587 struct list_head *lqueue; 588 struct sctp_transport *transport = pkt->transport; 589 sctp_xmit_t status; 590 struct sctp_chunk *chunk, *chunk1; 591 int fast_rtx; 592 int error = 0; 593 int timer = 0; 594 int done = 0; 595 596 lqueue = &q->retransmit; 597 fast_rtx = q->fast_rtx; 598 599 /* This loop handles time-out retransmissions, fast retransmissions, 600 * and retransmissions due to opening of whindow. 601 * 602 * RFC 2960 6.3.3 Handle T3-rtx Expiration 603 * 604 * E3) Determine how many of the earliest (i.e., lowest TSN) 605 * outstanding DATA chunks for the address for which the 606 * T3-rtx has expired will fit into a single packet, subject 607 * to the MTU constraint for the path corresponding to the 608 * destination transport address to which the retransmission 609 * is being sent (this may be different from the address for 610 * which the timer expires [see Section 6.4]). Call this value 611 * K. Bundle and retransmit those K DATA chunks in a single 612 * packet to the destination endpoint. 613 * 614 * [Just to be painfully clear, if we are retransmitting 615 * because a timeout just happened, we should send only ONE 616 * packet of retransmitted data.] 617 * 618 * For fast retransmissions we also send only ONE packet. However, 619 * if we are just flushing the queue due to open window, we'll 620 * try to send as much as possible. 621 */ 622 list_for_each_entry_safe(chunk, chunk1, lqueue, transmitted_list) { 623 /* If the chunk is abandoned, move it to abandoned list. */ 624 if (sctp_chunk_abandoned(chunk)) { 625 list_del_init(&chunk->transmitted_list); 626 sctp_insert_list(&q->abandoned, 627 &chunk->transmitted_list); 628 continue; 629 } 630 631 /* Make sure that Gap Acked TSNs are not retransmitted. A 632 * simple approach is just to move such TSNs out of the 633 * way and into a 'transmitted' queue and skip to the 634 * next chunk. 635 */ 636 if (chunk->tsn_gap_acked) { 637 list_move_tail(&chunk->transmitted_list, 638 &transport->transmitted); 639 continue; 640 } 641 642 /* If we are doing fast retransmit, ignore non-fast_rtransmit 643 * chunks 644 */ 645 if (fast_rtx && !chunk->fast_retransmit) 646 continue; 647 648 redo: 649 /* Attempt to append this chunk to the packet. */ 650 status = sctp_packet_append_chunk(pkt, chunk); 651 652 switch (status) { 653 case SCTP_XMIT_PMTU_FULL: 654 if (!pkt->has_data && !pkt->has_cookie_echo) { 655 /* If this packet did not contain DATA then 656 * retransmission did not happen, so do it 657 * again. We'll ignore the error here since 658 * control chunks are already freed so there 659 * is nothing we can do. 660 */ 661 sctp_packet_transmit(pkt, GFP_ATOMIC); 662 goto redo; 663 } 664 665 /* Send this packet. */ 666 error = sctp_packet_transmit(pkt, GFP_ATOMIC); 667 668 /* If we are retransmitting, we should only 669 * send a single packet. 670 * Otherwise, try appending this chunk again. 671 */ 672 if (rtx_timeout || fast_rtx) 673 done = 1; 674 else 675 goto redo; 676 677 /* Bundle next chunk in the next round. */ 678 break; 679 680 case SCTP_XMIT_RWND_FULL: 681 /* Send this packet. */ 682 error = sctp_packet_transmit(pkt, GFP_ATOMIC); 683 684 /* Stop sending DATA as there is no more room 685 * at the receiver. 686 */ 687 done = 1; 688 break; 689 690 case SCTP_XMIT_DELAY: 691 /* Send this packet. */ 692 error = sctp_packet_transmit(pkt, GFP_ATOMIC); 693 694 /* Stop sending DATA because of nagle delay. */ 695 done = 1; 696 break; 697 698 default: 699 /* The append was successful, so add this chunk to 700 * the transmitted list. 701 */ 702 list_move_tail(&chunk->transmitted_list, 703 &transport->transmitted); 704 705 /* Mark the chunk as ineligible for fast retransmit 706 * after it is retransmitted. 707 */ 708 if (chunk->fast_retransmit == SCTP_NEED_FRTX) 709 chunk->fast_retransmit = SCTP_DONT_FRTX; 710 711 q->asoc->stats.rtxchunks++; 712 break; 713 } 714 715 /* Set the timer if there were no errors */ 716 if (!error && !timer) 717 timer = 1; 718 719 if (done) 720 break; 721 } 722 723 /* If we are here due to a retransmit timeout or a fast 724 * retransmit and if there are any chunks left in the retransmit 725 * queue that could not fit in the PMTU sized packet, they need 726 * to be marked as ineligible for a subsequent fast retransmit. 727 */ 728 if (rtx_timeout || fast_rtx) { 729 list_for_each_entry(chunk1, lqueue, transmitted_list) { 730 if (chunk1->fast_retransmit == SCTP_NEED_FRTX) 731 chunk1->fast_retransmit = SCTP_DONT_FRTX; 732 } 733 } 734 735 *start_timer = timer; 736 737 /* Clear fast retransmit hint */ 738 if (fast_rtx) 739 q->fast_rtx = 0; 740 741 return error; 742 } 743 744 /* Cork the outqueue so queued chunks are really queued. */ 745 void sctp_outq_uncork(struct sctp_outq *q, gfp_t gfp) 746 { 747 if (q->cork) 748 q->cork = 0; 749 750 sctp_outq_flush(q, 0, gfp); 751 } 752 753 754 /* 755 * Try to flush an outqueue. 756 * 757 * Description: Send everything in q which we legally can, subject to 758 * congestion limitations. 759 * * Note: This function can be called from multiple contexts so appropriate 760 * locking concerns must be made. Today we use the sock lock to protect 761 * this function. 762 */ 763 static void sctp_outq_flush(struct sctp_outq *q, int rtx_timeout, gfp_t gfp) 764 { 765 struct sctp_packet *packet; 766 struct sctp_packet singleton; 767 struct sctp_association *asoc = q->asoc; 768 __u16 sport = asoc->base.bind_addr.port; 769 __u16 dport = asoc->peer.port; 770 __u32 vtag = asoc->peer.i.init_tag; 771 struct sctp_transport *transport = NULL; 772 struct sctp_transport *new_transport; 773 struct sctp_chunk *chunk, *tmp; 774 sctp_xmit_t status; 775 int error = 0; 776 int start_timer = 0; 777 int one_packet = 0; 778 779 /* These transports have chunks to send. */ 780 struct list_head transport_list; 781 struct list_head *ltransport; 782 783 INIT_LIST_HEAD(&transport_list); 784 packet = NULL; 785 786 /* 787 * 6.10 Bundling 788 * ... 789 * When bundling control chunks with DATA chunks, an 790 * endpoint MUST place control chunks first in the outbound 791 * SCTP packet. The transmitter MUST transmit DATA chunks 792 * within a SCTP packet in increasing order of TSN. 793 * ... 794 */ 795 796 list_for_each_entry_safe(chunk, tmp, &q->control_chunk_list, list) { 797 /* RFC 5061, 5.3 798 * F1) This means that until such time as the ASCONF 799 * containing the add is acknowledged, the sender MUST 800 * NOT use the new IP address as a source for ANY SCTP 801 * packet except on carrying an ASCONF Chunk. 802 */ 803 if (asoc->src_out_of_asoc_ok && 804 chunk->chunk_hdr->type != SCTP_CID_ASCONF) 805 continue; 806 807 list_del_init(&chunk->list); 808 809 /* Pick the right transport to use. */ 810 new_transport = chunk->transport; 811 812 if (!new_transport) { 813 /* 814 * If we have a prior transport pointer, see if 815 * the destination address of the chunk 816 * matches the destination address of the 817 * current transport. If not a match, then 818 * try to look up the transport with a given 819 * destination address. We do this because 820 * after processing ASCONFs, we may have new 821 * transports created. 822 */ 823 if (transport && 824 sctp_cmp_addr_exact(&chunk->dest, 825 &transport->ipaddr)) 826 new_transport = transport; 827 else 828 new_transport = sctp_assoc_lookup_paddr(asoc, 829 &chunk->dest); 830 831 /* if we still don't have a new transport, then 832 * use the current active path. 833 */ 834 if (!new_transport) 835 new_transport = asoc->peer.active_path; 836 } else if ((new_transport->state == SCTP_INACTIVE) || 837 (new_transport->state == SCTP_UNCONFIRMED) || 838 (new_transport->state == SCTP_PF)) { 839 /* If the chunk is Heartbeat or Heartbeat Ack, 840 * send it to chunk->transport, even if it's 841 * inactive. 842 * 843 * 3.3.6 Heartbeat Acknowledgement: 844 * ... 845 * A HEARTBEAT ACK is always sent to the source IP 846 * address of the IP datagram containing the 847 * HEARTBEAT chunk to which this ack is responding. 848 * ... 849 * 850 * ASCONF_ACKs also must be sent to the source. 851 */ 852 if (chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT && 853 chunk->chunk_hdr->type != SCTP_CID_HEARTBEAT_ACK && 854 chunk->chunk_hdr->type != SCTP_CID_ASCONF_ACK) 855 new_transport = asoc->peer.active_path; 856 } 857 858 /* Are we switching transports? 859 * Take care of transport locks. 860 */ 861 if (new_transport != transport) { 862 transport = new_transport; 863 if (list_empty(&transport->send_ready)) { 864 list_add_tail(&transport->send_ready, 865 &transport_list); 866 } 867 packet = &transport->packet; 868 sctp_packet_config(packet, vtag, 869 asoc->peer.ecn_capable); 870 } 871 872 switch (chunk->chunk_hdr->type) { 873 /* 874 * 6.10 Bundling 875 * ... 876 * An endpoint MUST NOT bundle INIT, INIT ACK or SHUTDOWN 877 * COMPLETE with any other chunks. [Send them immediately.] 878 */ 879 case SCTP_CID_INIT: 880 case SCTP_CID_INIT_ACK: 881 case SCTP_CID_SHUTDOWN_COMPLETE: 882 sctp_packet_init(&singleton, transport, sport, dport); 883 sctp_packet_config(&singleton, vtag, 0); 884 sctp_packet_append_chunk(&singleton, chunk); 885 error = sctp_packet_transmit(&singleton, gfp); 886 if (error < 0) { 887 asoc->base.sk->sk_err = -error; 888 return; 889 } 890 break; 891 892 case SCTP_CID_ABORT: 893 if (sctp_test_T_bit(chunk)) { 894 packet->vtag = asoc->c.my_vtag; 895 } 896 /* The following chunks are "response" chunks, i.e. 897 * they are generated in response to something we 898 * received. If we are sending these, then we can 899 * send only 1 packet containing these chunks. 900 */ 901 case SCTP_CID_HEARTBEAT_ACK: 902 case SCTP_CID_SHUTDOWN_ACK: 903 case SCTP_CID_COOKIE_ACK: 904 case SCTP_CID_COOKIE_ECHO: 905 case SCTP_CID_ERROR: 906 case SCTP_CID_ECN_CWR: 907 case SCTP_CID_ASCONF_ACK: 908 one_packet = 1; 909 /* Fall through */ 910 911 case SCTP_CID_SACK: 912 case SCTP_CID_HEARTBEAT: 913 case SCTP_CID_SHUTDOWN: 914 case SCTP_CID_ECN_ECNE: 915 case SCTP_CID_ASCONF: 916 case SCTP_CID_FWD_TSN: 917 case SCTP_CID_RECONF: 918 status = sctp_packet_transmit_chunk(packet, chunk, 919 one_packet, gfp); 920 if (status != SCTP_XMIT_OK) { 921 /* put the chunk back */ 922 list_add(&chunk->list, &q->control_chunk_list); 923 break; 924 } 925 926 asoc->stats.octrlchunks++; 927 /* PR-SCTP C5) If a FORWARD TSN is sent, the 928 * sender MUST assure that at least one T3-rtx 929 * timer is running. 930 */ 931 if (chunk->chunk_hdr->type == SCTP_CID_FWD_TSN) { 932 sctp_transport_reset_t3_rtx(transport); 933 transport->last_time_sent = jiffies; 934 } 935 936 if (chunk == asoc->strreset_chunk) 937 sctp_transport_reset_reconf_timer(transport); 938 939 break; 940 941 default: 942 /* We built a chunk with an illegal type! */ 943 BUG(); 944 } 945 } 946 947 if (q->asoc->src_out_of_asoc_ok) 948 goto sctp_flush_out; 949 950 /* Is it OK to send data chunks? */ 951 switch (asoc->state) { 952 case SCTP_STATE_COOKIE_ECHOED: 953 /* Only allow bundling when this packet has a COOKIE-ECHO 954 * chunk. 955 */ 956 if (!packet || !packet->has_cookie_echo) 957 break; 958 959 /* fallthru */ 960 case SCTP_STATE_ESTABLISHED: 961 case SCTP_STATE_SHUTDOWN_PENDING: 962 case SCTP_STATE_SHUTDOWN_RECEIVED: 963 /* 964 * RFC 2960 6.1 Transmission of DATA Chunks 965 * 966 * C) When the time comes for the sender to transmit, 967 * before sending new DATA chunks, the sender MUST 968 * first transmit any outstanding DATA chunks which 969 * are marked for retransmission (limited by the 970 * current cwnd). 971 */ 972 if (!list_empty(&q->retransmit)) { 973 if (asoc->peer.retran_path->state == SCTP_UNCONFIRMED) 974 goto sctp_flush_out; 975 if (transport == asoc->peer.retran_path) 976 goto retran; 977 978 /* Switch transports & prepare the packet. */ 979 980 transport = asoc->peer.retran_path; 981 982 if (list_empty(&transport->send_ready)) { 983 list_add_tail(&transport->send_ready, 984 &transport_list); 985 } 986 987 packet = &transport->packet; 988 sctp_packet_config(packet, vtag, 989 asoc->peer.ecn_capable); 990 retran: 991 error = sctp_outq_flush_rtx(q, packet, 992 rtx_timeout, &start_timer); 993 if (error < 0) 994 asoc->base.sk->sk_err = -error; 995 996 if (start_timer) { 997 sctp_transport_reset_t3_rtx(transport); 998 transport->last_time_sent = jiffies; 999 } 1000 1001 /* This can happen on COOKIE-ECHO resend. Only 1002 * one chunk can get bundled with a COOKIE-ECHO. 1003 */ 1004 if (packet->has_cookie_echo) 1005 goto sctp_flush_out; 1006 1007 /* Don't send new data if there is still data 1008 * waiting to retransmit. 1009 */ 1010 if (!list_empty(&q->retransmit)) 1011 goto sctp_flush_out; 1012 } 1013 1014 /* Apply Max.Burst limitation to the current transport in 1015 * case it will be used for new data. We are going to 1016 * rest it before we return, but we want to apply the limit 1017 * to the currently queued data. 1018 */ 1019 if (transport) 1020 sctp_transport_burst_limited(transport); 1021 1022 /* Finally, transmit new packets. */ 1023 while ((chunk = sctp_outq_dequeue_data(q)) != NULL) { 1024 __u32 sid = ntohs(chunk->subh.data_hdr->stream); 1025 1026 /* RFC 2960 6.5 Every DATA chunk MUST carry a valid 1027 * stream identifier. 1028 */ 1029 if (chunk->sinfo.sinfo_stream >= asoc->stream->outcnt) { 1030 1031 /* Mark as failed send. */ 1032 sctp_chunk_fail(chunk, SCTP_ERROR_INV_STRM); 1033 if (asoc->peer.prsctp_capable && 1034 SCTP_PR_PRIO_ENABLED(chunk->sinfo.sinfo_flags)) 1035 asoc->sent_cnt_removable--; 1036 sctp_chunk_free(chunk); 1037 continue; 1038 } 1039 1040 /* Has this chunk expired? */ 1041 if (sctp_chunk_abandoned(chunk)) { 1042 sctp_chunk_fail(chunk, 0); 1043 sctp_chunk_free(chunk); 1044 continue; 1045 } 1046 1047 if (asoc->stream->out[sid].state == SCTP_STREAM_CLOSED) { 1048 sctp_outq_head_data(q, chunk); 1049 goto sctp_flush_out; 1050 } 1051 1052 /* If there is a specified transport, use it. 1053 * Otherwise, we want to use the active path. 1054 */ 1055 new_transport = chunk->transport; 1056 if (!new_transport || 1057 ((new_transport->state == SCTP_INACTIVE) || 1058 (new_transport->state == SCTP_UNCONFIRMED) || 1059 (new_transport->state == SCTP_PF))) 1060 new_transport = asoc->peer.active_path; 1061 if (new_transport->state == SCTP_UNCONFIRMED) { 1062 WARN_ONCE(1, "Attempt to send packet on unconfirmed path."); 1063 sctp_chunk_fail(chunk, 0); 1064 sctp_chunk_free(chunk); 1065 continue; 1066 } 1067 1068 /* Change packets if necessary. */ 1069 if (new_transport != transport) { 1070 transport = new_transport; 1071 1072 /* Schedule to have this transport's 1073 * packet flushed. 1074 */ 1075 if (list_empty(&transport->send_ready)) { 1076 list_add_tail(&transport->send_ready, 1077 &transport_list); 1078 } 1079 1080 packet = &transport->packet; 1081 sctp_packet_config(packet, vtag, 1082 asoc->peer.ecn_capable); 1083 /* We've switched transports, so apply the 1084 * Burst limit to the new transport. 1085 */ 1086 sctp_transport_burst_limited(transport); 1087 } 1088 1089 pr_debug("%s: outq:%p, chunk:%p[%s], tx-tsn:0x%x skb->head:%p " 1090 "skb->users:%d\n", 1091 __func__, q, chunk, chunk && chunk->chunk_hdr ? 1092 sctp_cname(SCTP_ST_CHUNK(chunk->chunk_hdr->type)) : 1093 "illegal chunk", ntohl(chunk->subh.data_hdr->tsn), 1094 chunk->skb ? chunk->skb->head : NULL, chunk->skb ? 1095 atomic_read(&chunk->skb->users) : -1); 1096 1097 /* Add the chunk to the packet. */ 1098 status = sctp_packet_transmit_chunk(packet, chunk, 0, gfp); 1099 1100 switch (status) { 1101 case SCTP_XMIT_PMTU_FULL: 1102 case SCTP_XMIT_RWND_FULL: 1103 case SCTP_XMIT_DELAY: 1104 /* We could not append this chunk, so put 1105 * the chunk back on the output queue. 1106 */ 1107 pr_debug("%s: could not transmit tsn:0x%x, status:%d\n", 1108 __func__, ntohl(chunk->subh.data_hdr->tsn), 1109 status); 1110 1111 sctp_outq_head_data(q, chunk); 1112 goto sctp_flush_out; 1113 1114 case SCTP_XMIT_OK: 1115 /* The sender is in the SHUTDOWN-PENDING state, 1116 * The sender MAY set the I-bit in the DATA 1117 * chunk header. 1118 */ 1119 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING) 1120 chunk->chunk_hdr->flags |= SCTP_DATA_SACK_IMM; 1121 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) 1122 asoc->stats.ouodchunks++; 1123 else 1124 asoc->stats.oodchunks++; 1125 1126 break; 1127 1128 default: 1129 BUG(); 1130 } 1131 1132 /* BUG: We assume that the sctp_packet_transmit() 1133 * call below will succeed all the time and add the 1134 * chunk to the transmitted list and restart the 1135 * timers. 1136 * It is possible that the call can fail under OOM 1137 * conditions. 1138 * 1139 * Is this really a problem? Won't this behave 1140 * like a lost TSN? 1141 */ 1142 list_add_tail(&chunk->transmitted_list, 1143 &transport->transmitted); 1144 1145 sctp_transport_reset_t3_rtx(transport); 1146 transport->last_time_sent = jiffies; 1147 1148 /* Only let one DATA chunk get bundled with a 1149 * COOKIE-ECHO chunk. 1150 */ 1151 if (packet->has_cookie_echo) 1152 goto sctp_flush_out; 1153 } 1154 break; 1155 1156 default: 1157 /* Do nothing. */ 1158 break; 1159 } 1160 1161 sctp_flush_out: 1162 1163 /* Before returning, examine all the transports touched in 1164 * this call. Right now, we bluntly force clear all the 1165 * transports. Things might change after we implement Nagle. 1166 * But such an examination is still required. 1167 * 1168 * --xguo 1169 */ 1170 while ((ltransport = sctp_list_dequeue(&transport_list)) != NULL) { 1171 struct sctp_transport *t = list_entry(ltransport, 1172 struct sctp_transport, 1173 send_ready); 1174 packet = &t->packet; 1175 if (!sctp_packet_empty(packet)) { 1176 error = sctp_packet_transmit(packet, gfp); 1177 if (error < 0) 1178 asoc->base.sk->sk_err = -error; 1179 } 1180 1181 /* Clear the burst limited state, if any */ 1182 sctp_transport_burst_reset(t); 1183 } 1184 } 1185 1186 /* Update unack_data based on the incoming SACK chunk */ 1187 static void sctp_sack_update_unack_data(struct sctp_association *assoc, 1188 struct sctp_sackhdr *sack) 1189 { 1190 sctp_sack_variable_t *frags; 1191 __u16 unack_data; 1192 int i; 1193 1194 unack_data = assoc->next_tsn - assoc->ctsn_ack_point - 1; 1195 1196 frags = sack->variable; 1197 for (i = 0; i < ntohs(sack->num_gap_ack_blocks); i++) { 1198 unack_data -= ((ntohs(frags[i].gab.end) - 1199 ntohs(frags[i].gab.start) + 1)); 1200 } 1201 1202 assoc->unack_data = unack_data; 1203 } 1204 1205 /* This is where we REALLY process a SACK. 1206 * 1207 * Process the SACK against the outqueue. Mostly, this just frees 1208 * things off the transmitted queue. 1209 */ 1210 int sctp_outq_sack(struct sctp_outq *q, struct sctp_chunk *chunk) 1211 { 1212 struct sctp_association *asoc = q->asoc; 1213 struct sctp_sackhdr *sack = chunk->subh.sack_hdr; 1214 struct sctp_transport *transport; 1215 struct sctp_chunk *tchunk = NULL; 1216 struct list_head *lchunk, *transport_list, *temp; 1217 sctp_sack_variable_t *frags = sack->variable; 1218 __u32 sack_ctsn, ctsn, tsn; 1219 __u32 highest_tsn, highest_new_tsn; 1220 __u32 sack_a_rwnd; 1221 unsigned int outstanding; 1222 struct sctp_transport *primary = asoc->peer.primary_path; 1223 int count_of_newacks = 0; 1224 int gap_ack_blocks; 1225 u8 accum_moved = 0; 1226 1227 /* Grab the association's destination address list. */ 1228 transport_list = &asoc->peer.transport_addr_list; 1229 1230 sack_ctsn = ntohl(sack->cum_tsn_ack); 1231 gap_ack_blocks = ntohs(sack->num_gap_ack_blocks); 1232 asoc->stats.gapcnt += gap_ack_blocks; 1233 /* 1234 * SFR-CACC algorithm: 1235 * On receipt of a SACK the sender SHOULD execute the 1236 * following statements. 1237 * 1238 * 1) If the cumulative ack in the SACK passes next tsn_at_change 1239 * on the current primary, the CHANGEOVER_ACTIVE flag SHOULD be 1240 * cleared. The CYCLING_CHANGEOVER flag SHOULD also be cleared for 1241 * all destinations. 1242 * 2) If the SACK contains gap acks and the flag CHANGEOVER_ACTIVE 1243 * is set the receiver of the SACK MUST take the following actions: 1244 * 1245 * A) Initialize the cacc_saw_newack to 0 for all destination 1246 * addresses. 1247 * 1248 * Only bother if changeover_active is set. Otherwise, this is 1249 * totally suboptimal to do on every SACK. 1250 */ 1251 if (primary->cacc.changeover_active) { 1252 u8 clear_cycling = 0; 1253 1254 if (TSN_lte(primary->cacc.next_tsn_at_change, sack_ctsn)) { 1255 primary->cacc.changeover_active = 0; 1256 clear_cycling = 1; 1257 } 1258 1259 if (clear_cycling || gap_ack_blocks) { 1260 list_for_each_entry(transport, transport_list, 1261 transports) { 1262 if (clear_cycling) 1263 transport->cacc.cycling_changeover = 0; 1264 if (gap_ack_blocks) 1265 transport->cacc.cacc_saw_newack = 0; 1266 } 1267 } 1268 } 1269 1270 /* Get the highest TSN in the sack. */ 1271 highest_tsn = sack_ctsn; 1272 if (gap_ack_blocks) 1273 highest_tsn += ntohs(frags[gap_ack_blocks - 1].gab.end); 1274 1275 if (TSN_lt(asoc->highest_sacked, highest_tsn)) 1276 asoc->highest_sacked = highest_tsn; 1277 1278 highest_new_tsn = sack_ctsn; 1279 1280 /* Run through the retransmit queue. Credit bytes received 1281 * and free those chunks that we can. 1282 */ 1283 sctp_check_transmitted(q, &q->retransmit, NULL, NULL, sack, &highest_new_tsn); 1284 1285 /* Run through the transmitted queue. 1286 * Credit bytes received and free those chunks which we can. 1287 * 1288 * This is a MASSIVE candidate for optimization. 1289 */ 1290 list_for_each_entry(transport, transport_list, transports) { 1291 sctp_check_transmitted(q, &transport->transmitted, 1292 transport, &chunk->source, sack, 1293 &highest_new_tsn); 1294 /* 1295 * SFR-CACC algorithm: 1296 * C) Let count_of_newacks be the number of 1297 * destinations for which cacc_saw_newack is set. 1298 */ 1299 if (transport->cacc.cacc_saw_newack) 1300 count_of_newacks++; 1301 } 1302 1303 /* Move the Cumulative TSN Ack Point if appropriate. */ 1304 if (TSN_lt(asoc->ctsn_ack_point, sack_ctsn)) { 1305 asoc->ctsn_ack_point = sack_ctsn; 1306 accum_moved = 1; 1307 } 1308 1309 if (gap_ack_blocks) { 1310 1311 if (asoc->fast_recovery && accum_moved) 1312 highest_new_tsn = highest_tsn; 1313 1314 list_for_each_entry(transport, transport_list, transports) 1315 sctp_mark_missing(q, &transport->transmitted, transport, 1316 highest_new_tsn, count_of_newacks); 1317 } 1318 1319 /* Update unack_data field in the assoc. */ 1320 sctp_sack_update_unack_data(asoc, sack); 1321 1322 ctsn = asoc->ctsn_ack_point; 1323 1324 /* Throw away stuff rotting on the sack queue. */ 1325 list_for_each_safe(lchunk, temp, &q->sacked) { 1326 tchunk = list_entry(lchunk, struct sctp_chunk, 1327 transmitted_list); 1328 tsn = ntohl(tchunk->subh.data_hdr->tsn); 1329 if (TSN_lte(tsn, ctsn)) { 1330 list_del_init(&tchunk->transmitted_list); 1331 if (asoc->peer.prsctp_capable && 1332 SCTP_PR_PRIO_ENABLED(chunk->sinfo.sinfo_flags)) 1333 asoc->sent_cnt_removable--; 1334 sctp_chunk_free(tchunk); 1335 } 1336 } 1337 1338 /* ii) Set rwnd equal to the newly received a_rwnd minus the 1339 * number of bytes still outstanding after processing the 1340 * Cumulative TSN Ack and the Gap Ack Blocks. 1341 */ 1342 1343 sack_a_rwnd = ntohl(sack->a_rwnd); 1344 asoc->peer.zero_window_announced = !sack_a_rwnd; 1345 outstanding = q->outstanding_bytes; 1346 1347 if (outstanding < sack_a_rwnd) 1348 sack_a_rwnd -= outstanding; 1349 else 1350 sack_a_rwnd = 0; 1351 1352 asoc->peer.rwnd = sack_a_rwnd; 1353 1354 sctp_generate_fwdtsn(q, sack_ctsn); 1355 1356 pr_debug("%s: sack cumulative tsn ack:0x%x\n", __func__, sack_ctsn); 1357 pr_debug("%s: cumulative tsn ack of assoc:%p is 0x%x, " 1358 "advertised peer ack point:0x%x\n", __func__, asoc, ctsn, 1359 asoc->adv_peer_ack_point); 1360 1361 return sctp_outq_is_empty(q); 1362 } 1363 1364 /* Is the outqueue empty? 1365 * The queue is empty when we have not pending data, no in-flight data 1366 * and nothing pending retransmissions. 1367 */ 1368 int sctp_outq_is_empty(const struct sctp_outq *q) 1369 { 1370 return q->out_qlen == 0 && q->outstanding_bytes == 0 && 1371 list_empty(&q->retransmit); 1372 } 1373 1374 /******************************************************************** 1375 * 2nd Level Abstractions 1376 ********************************************************************/ 1377 1378 /* Go through a transport's transmitted list or the association's retransmit 1379 * list and move chunks that are acked by the Cumulative TSN Ack to q->sacked. 1380 * The retransmit list will not have an associated transport. 1381 * 1382 * I added coherent debug information output. --xguo 1383 * 1384 * Instead of printing 'sacked' or 'kept' for each TSN on the 1385 * transmitted_queue, we print a range: SACKED: TSN1-TSN2, TSN3, TSN4-TSN5. 1386 * KEPT TSN6-TSN7, etc. 1387 */ 1388 static void sctp_check_transmitted(struct sctp_outq *q, 1389 struct list_head *transmitted_queue, 1390 struct sctp_transport *transport, 1391 union sctp_addr *saddr, 1392 struct sctp_sackhdr *sack, 1393 __u32 *highest_new_tsn_in_sack) 1394 { 1395 struct list_head *lchunk; 1396 struct sctp_chunk *tchunk; 1397 struct list_head tlist; 1398 __u32 tsn; 1399 __u32 sack_ctsn; 1400 __u32 rtt; 1401 __u8 restart_timer = 0; 1402 int bytes_acked = 0; 1403 int migrate_bytes = 0; 1404 bool forward_progress = false; 1405 1406 sack_ctsn = ntohl(sack->cum_tsn_ack); 1407 1408 INIT_LIST_HEAD(&tlist); 1409 1410 /* The while loop will skip empty transmitted queues. */ 1411 while (NULL != (lchunk = sctp_list_dequeue(transmitted_queue))) { 1412 tchunk = list_entry(lchunk, struct sctp_chunk, 1413 transmitted_list); 1414 1415 if (sctp_chunk_abandoned(tchunk)) { 1416 /* Move the chunk to abandoned list. */ 1417 sctp_insert_list(&q->abandoned, lchunk); 1418 1419 /* If this chunk has not been acked, stop 1420 * considering it as 'outstanding'. 1421 */ 1422 if (!tchunk->tsn_gap_acked) { 1423 if (tchunk->transport) 1424 tchunk->transport->flight_size -= 1425 sctp_data_size(tchunk); 1426 q->outstanding_bytes -= sctp_data_size(tchunk); 1427 } 1428 continue; 1429 } 1430 1431 tsn = ntohl(tchunk->subh.data_hdr->tsn); 1432 if (sctp_acked(sack, tsn)) { 1433 /* If this queue is the retransmit queue, the 1434 * retransmit timer has already reclaimed 1435 * the outstanding bytes for this chunk, so only 1436 * count bytes associated with a transport. 1437 */ 1438 if (transport) { 1439 /* If this chunk is being used for RTT 1440 * measurement, calculate the RTT and update 1441 * the RTO using this value. 1442 * 1443 * 6.3.1 C5) Karn's algorithm: RTT measurements 1444 * MUST NOT be made using packets that were 1445 * retransmitted (and thus for which it is 1446 * ambiguous whether the reply was for the 1447 * first instance of the packet or a later 1448 * instance). 1449 */ 1450 if (!tchunk->tsn_gap_acked && 1451 !sctp_chunk_retransmitted(tchunk) && 1452 tchunk->rtt_in_progress) { 1453 tchunk->rtt_in_progress = 0; 1454 rtt = jiffies - tchunk->sent_at; 1455 sctp_transport_update_rto(transport, 1456 rtt); 1457 } 1458 } 1459 1460 /* If the chunk hasn't been marked as ACKED, 1461 * mark it and account bytes_acked if the 1462 * chunk had a valid transport (it will not 1463 * have a transport if ASCONF had deleted it 1464 * while DATA was outstanding). 1465 */ 1466 if (!tchunk->tsn_gap_acked) { 1467 tchunk->tsn_gap_acked = 1; 1468 if (TSN_lt(*highest_new_tsn_in_sack, tsn)) 1469 *highest_new_tsn_in_sack = tsn; 1470 bytes_acked += sctp_data_size(tchunk); 1471 if (!tchunk->transport) 1472 migrate_bytes += sctp_data_size(tchunk); 1473 forward_progress = true; 1474 } 1475 1476 if (TSN_lte(tsn, sack_ctsn)) { 1477 /* RFC 2960 6.3.2 Retransmission Timer Rules 1478 * 1479 * R3) Whenever a SACK is received 1480 * that acknowledges the DATA chunk 1481 * with the earliest outstanding TSN 1482 * for that address, restart T3-rtx 1483 * timer for that address with its 1484 * current RTO. 1485 */ 1486 restart_timer = 1; 1487 forward_progress = true; 1488 1489 if (!tchunk->tsn_gap_acked) { 1490 /* 1491 * SFR-CACC algorithm: 1492 * 2) If the SACK contains gap acks 1493 * and the flag CHANGEOVER_ACTIVE is 1494 * set the receiver of the SACK MUST 1495 * take the following action: 1496 * 1497 * B) For each TSN t being acked that 1498 * has not been acked in any SACK so 1499 * far, set cacc_saw_newack to 1 for 1500 * the destination that the TSN was 1501 * sent to. 1502 */ 1503 if (transport && 1504 sack->num_gap_ack_blocks && 1505 q->asoc->peer.primary_path->cacc. 1506 changeover_active) 1507 transport->cacc.cacc_saw_newack 1508 = 1; 1509 } 1510 1511 list_add_tail(&tchunk->transmitted_list, 1512 &q->sacked); 1513 } else { 1514 /* RFC2960 7.2.4, sctpimpguide-05 2.8.2 1515 * M2) Each time a SACK arrives reporting 1516 * 'Stray DATA chunk(s)' record the highest TSN 1517 * reported as newly acknowledged, call this 1518 * value 'HighestTSNinSack'. A newly 1519 * acknowledged DATA chunk is one not 1520 * previously acknowledged in a SACK. 1521 * 1522 * When the SCTP sender of data receives a SACK 1523 * chunk that acknowledges, for the first time, 1524 * the receipt of a DATA chunk, all the still 1525 * unacknowledged DATA chunks whose TSN is 1526 * older than that newly acknowledged DATA 1527 * chunk, are qualified as 'Stray DATA chunks'. 1528 */ 1529 list_add_tail(lchunk, &tlist); 1530 } 1531 } else { 1532 if (tchunk->tsn_gap_acked) { 1533 pr_debug("%s: receiver reneged on data TSN:0x%x\n", 1534 __func__, tsn); 1535 1536 tchunk->tsn_gap_acked = 0; 1537 1538 if (tchunk->transport) 1539 bytes_acked -= sctp_data_size(tchunk); 1540 1541 /* RFC 2960 6.3.2 Retransmission Timer Rules 1542 * 1543 * R4) Whenever a SACK is received missing a 1544 * TSN that was previously acknowledged via a 1545 * Gap Ack Block, start T3-rtx for the 1546 * destination address to which the DATA 1547 * chunk was originally 1548 * transmitted if it is not already running. 1549 */ 1550 restart_timer = 1; 1551 } 1552 1553 list_add_tail(lchunk, &tlist); 1554 } 1555 } 1556 1557 if (transport) { 1558 if (bytes_acked) { 1559 struct sctp_association *asoc = transport->asoc; 1560 1561 /* We may have counted DATA that was migrated 1562 * to this transport due to DEL-IP operation. 1563 * Subtract those bytes, since the were never 1564 * send on this transport and shouldn't be 1565 * credited to this transport. 1566 */ 1567 bytes_acked -= migrate_bytes; 1568 1569 /* 8.2. When an outstanding TSN is acknowledged, 1570 * the endpoint shall clear the error counter of 1571 * the destination transport address to which the 1572 * DATA chunk was last sent. 1573 * The association's overall error counter is 1574 * also cleared. 1575 */ 1576 transport->error_count = 0; 1577 transport->asoc->overall_error_count = 0; 1578 forward_progress = true; 1579 1580 /* 1581 * While in SHUTDOWN PENDING, we may have started 1582 * the T5 shutdown guard timer after reaching the 1583 * retransmission limit. Stop that timer as soon 1584 * as the receiver acknowledged any data. 1585 */ 1586 if (asoc->state == SCTP_STATE_SHUTDOWN_PENDING && 1587 del_timer(&asoc->timers 1588 [SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD])) 1589 sctp_association_put(asoc); 1590 1591 /* Mark the destination transport address as 1592 * active if it is not so marked. 1593 */ 1594 if ((transport->state == SCTP_INACTIVE || 1595 transport->state == SCTP_UNCONFIRMED) && 1596 sctp_cmp_addr_exact(&transport->ipaddr, saddr)) { 1597 sctp_assoc_control_transport( 1598 transport->asoc, 1599 transport, 1600 SCTP_TRANSPORT_UP, 1601 SCTP_RECEIVED_SACK); 1602 } 1603 1604 sctp_transport_raise_cwnd(transport, sack_ctsn, 1605 bytes_acked); 1606 1607 transport->flight_size -= bytes_acked; 1608 if (transport->flight_size == 0) 1609 transport->partial_bytes_acked = 0; 1610 q->outstanding_bytes -= bytes_acked + migrate_bytes; 1611 } else { 1612 /* RFC 2960 6.1, sctpimpguide-06 2.15.2 1613 * When a sender is doing zero window probing, it 1614 * should not timeout the association if it continues 1615 * to receive new packets from the receiver. The 1616 * reason is that the receiver MAY keep its window 1617 * closed for an indefinite time. 1618 * A sender is doing zero window probing when the 1619 * receiver's advertised window is zero, and there is 1620 * only one data chunk in flight to the receiver. 1621 * 1622 * Allow the association to timeout while in SHUTDOWN 1623 * PENDING or SHUTDOWN RECEIVED in case the receiver 1624 * stays in zero window mode forever. 1625 */ 1626 if (!q->asoc->peer.rwnd && 1627 !list_empty(&tlist) && 1628 (sack_ctsn+2 == q->asoc->next_tsn) && 1629 q->asoc->state < SCTP_STATE_SHUTDOWN_PENDING) { 1630 pr_debug("%s: sack received for zero window " 1631 "probe:%u\n", __func__, sack_ctsn); 1632 1633 q->asoc->overall_error_count = 0; 1634 transport->error_count = 0; 1635 } 1636 } 1637 1638 /* RFC 2960 6.3.2 Retransmission Timer Rules 1639 * 1640 * R2) Whenever all outstanding data sent to an address have 1641 * been acknowledged, turn off the T3-rtx timer of that 1642 * address. 1643 */ 1644 if (!transport->flight_size) { 1645 if (del_timer(&transport->T3_rtx_timer)) 1646 sctp_transport_put(transport); 1647 } else if (restart_timer) { 1648 if (!mod_timer(&transport->T3_rtx_timer, 1649 jiffies + transport->rto)) 1650 sctp_transport_hold(transport); 1651 } 1652 1653 if (forward_progress) { 1654 if (transport->dst) 1655 sctp_transport_dst_confirm(transport); 1656 } 1657 } 1658 1659 list_splice(&tlist, transmitted_queue); 1660 } 1661 1662 /* Mark chunks as missing and consequently may get retransmitted. */ 1663 static void sctp_mark_missing(struct sctp_outq *q, 1664 struct list_head *transmitted_queue, 1665 struct sctp_transport *transport, 1666 __u32 highest_new_tsn_in_sack, 1667 int count_of_newacks) 1668 { 1669 struct sctp_chunk *chunk; 1670 __u32 tsn; 1671 char do_fast_retransmit = 0; 1672 struct sctp_association *asoc = q->asoc; 1673 struct sctp_transport *primary = asoc->peer.primary_path; 1674 1675 list_for_each_entry(chunk, transmitted_queue, transmitted_list) { 1676 1677 tsn = ntohl(chunk->subh.data_hdr->tsn); 1678 1679 /* RFC 2960 7.2.4, sctpimpguide-05 2.8.2 M3) Examine all 1680 * 'Unacknowledged TSN's', if the TSN number of an 1681 * 'Unacknowledged TSN' is smaller than the 'HighestTSNinSack' 1682 * value, increment the 'TSN.Missing.Report' count on that 1683 * chunk if it has NOT been fast retransmitted or marked for 1684 * fast retransmit already. 1685 */ 1686 if (chunk->fast_retransmit == SCTP_CAN_FRTX && 1687 !chunk->tsn_gap_acked && 1688 TSN_lt(tsn, highest_new_tsn_in_sack)) { 1689 1690 /* SFR-CACC may require us to skip marking 1691 * this chunk as missing. 1692 */ 1693 if (!transport || !sctp_cacc_skip(primary, 1694 chunk->transport, 1695 count_of_newacks, tsn)) { 1696 chunk->tsn_missing_report++; 1697 1698 pr_debug("%s: tsn:0x%x missing counter:%d\n", 1699 __func__, tsn, chunk->tsn_missing_report); 1700 } 1701 } 1702 /* 1703 * M4) If any DATA chunk is found to have a 1704 * 'TSN.Missing.Report' 1705 * value larger than or equal to 3, mark that chunk for 1706 * retransmission and start the fast retransmit procedure. 1707 */ 1708 1709 if (chunk->tsn_missing_report >= 3) { 1710 chunk->fast_retransmit = SCTP_NEED_FRTX; 1711 do_fast_retransmit = 1; 1712 } 1713 } 1714 1715 if (transport) { 1716 if (do_fast_retransmit) 1717 sctp_retransmit(q, transport, SCTP_RTXR_FAST_RTX); 1718 1719 pr_debug("%s: transport:%p, cwnd:%d, ssthresh:%d, " 1720 "flight_size:%d, pba:%d\n", __func__, transport, 1721 transport->cwnd, transport->ssthresh, 1722 transport->flight_size, transport->partial_bytes_acked); 1723 } 1724 } 1725 1726 /* Is the given TSN acked by this packet? */ 1727 static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn) 1728 { 1729 int i; 1730 sctp_sack_variable_t *frags; 1731 __u16 tsn_offset, blocks; 1732 __u32 ctsn = ntohl(sack->cum_tsn_ack); 1733 1734 if (TSN_lte(tsn, ctsn)) 1735 goto pass; 1736 1737 /* 3.3.4 Selective Acknowledgement (SACK) (3): 1738 * 1739 * Gap Ack Blocks: 1740 * These fields contain the Gap Ack Blocks. They are repeated 1741 * for each Gap Ack Block up to the number of Gap Ack Blocks 1742 * defined in the Number of Gap Ack Blocks field. All DATA 1743 * chunks with TSNs greater than or equal to (Cumulative TSN 1744 * Ack + Gap Ack Block Start) and less than or equal to 1745 * (Cumulative TSN Ack + Gap Ack Block End) of each Gap Ack 1746 * Block are assumed to have been received correctly. 1747 */ 1748 1749 frags = sack->variable; 1750 blocks = ntohs(sack->num_gap_ack_blocks); 1751 tsn_offset = tsn - ctsn; 1752 for (i = 0; i < blocks; ++i) { 1753 if (tsn_offset >= ntohs(frags[i].gab.start) && 1754 tsn_offset <= ntohs(frags[i].gab.end)) 1755 goto pass; 1756 } 1757 1758 return 0; 1759 pass: 1760 return 1; 1761 } 1762 1763 static inline int sctp_get_skip_pos(struct sctp_fwdtsn_skip *skiplist, 1764 int nskips, __be16 stream) 1765 { 1766 int i; 1767 1768 for (i = 0; i < nskips; i++) { 1769 if (skiplist[i].stream == stream) 1770 return i; 1771 } 1772 return i; 1773 } 1774 1775 /* Create and add a fwdtsn chunk to the outq's control queue if needed. */ 1776 static void sctp_generate_fwdtsn(struct sctp_outq *q, __u32 ctsn) 1777 { 1778 struct sctp_association *asoc = q->asoc; 1779 struct sctp_chunk *ftsn_chunk = NULL; 1780 struct sctp_fwdtsn_skip ftsn_skip_arr[10]; 1781 int nskips = 0; 1782 int skip_pos = 0; 1783 __u32 tsn; 1784 struct sctp_chunk *chunk; 1785 struct list_head *lchunk, *temp; 1786 1787 if (!asoc->peer.prsctp_capable) 1788 return; 1789 1790 /* PR-SCTP C1) Let SackCumAck be the Cumulative TSN ACK carried in the 1791 * received SACK. 1792 * 1793 * If (Advanced.Peer.Ack.Point < SackCumAck), then update 1794 * Advanced.Peer.Ack.Point to be equal to SackCumAck. 1795 */ 1796 if (TSN_lt(asoc->adv_peer_ack_point, ctsn)) 1797 asoc->adv_peer_ack_point = ctsn; 1798 1799 /* PR-SCTP C2) Try to further advance the "Advanced.Peer.Ack.Point" 1800 * locally, that is, to move "Advanced.Peer.Ack.Point" up as long as 1801 * the chunk next in the out-queue space is marked as "abandoned" as 1802 * shown in the following example: 1803 * 1804 * Assuming that a SACK arrived with the Cumulative TSN ACK 102 1805 * and the Advanced.Peer.Ack.Point is updated to this value: 1806 * 1807 * out-queue at the end of ==> out-queue after Adv.Ack.Point 1808 * normal SACK processing local advancement 1809 * ... ... 1810 * Adv.Ack.Pt-> 102 acked 102 acked 1811 * 103 abandoned 103 abandoned 1812 * 104 abandoned Adv.Ack.P-> 104 abandoned 1813 * 105 105 1814 * 106 acked 106 acked 1815 * ... ... 1816 * 1817 * In this example, the data sender successfully advanced the 1818 * "Advanced.Peer.Ack.Point" from 102 to 104 locally. 1819 */ 1820 list_for_each_safe(lchunk, temp, &q->abandoned) { 1821 chunk = list_entry(lchunk, struct sctp_chunk, 1822 transmitted_list); 1823 tsn = ntohl(chunk->subh.data_hdr->tsn); 1824 1825 /* Remove any chunks in the abandoned queue that are acked by 1826 * the ctsn. 1827 */ 1828 if (TSN_lte(tsn, ctsn)) { 1829 list_del_init(lchunk); 1830 sctp_chunk_free(chunk); 1831 } else { 1832 if (TSN_lte(tsn, asoc->adv_peer_ack_point+1)) { 1833 asoc->adv_peer_ack_point = tsn; 1834 if (chunk->chunk_hdr->flags & 1835 SCTP_DATA_UNORDERED) 1836 continue; 1837 skip_pos = sctp_get_skip_pos(&ftsn_skip_arr[0], 1838 nskips, 1839 chunk->subh.data_hdr->stream); 1840 ftsn_skip_arr[skip_pos].stream = 1841 chunk->subh.data_hdr->stream; 1842 ftsn_skip_arr[skip_pos].ssn = 1843 chunk->subh.data_hdr->ssn; 1844 if (skip_pos == nskips) 1845 nskips++; 1846 if (nskips == 10) 1847 break; 1848 } else 1849 break; 1850 } 1851 } 1852 1853 /* PR-SCTP C3) If, after step C1 and C2, the "Advanced.Peer.Ack.Point" 1854 * is greater than the Cumulative TSN ACK carried in the received 1855 * SACK, the data sender MUST send the data receiver a FORWARD TSN 1856 * chunk containing the latest value of the 1857 * "Advanced.Peer.Ack.Point". 1858 * 1859 * C4) For each "abandoned" TSN the sender of the FORWARD TSN SHOULD 1860 * list each stream and sequence number in the forwarded TSN. This 1861 * information will enable the receiver to easily find any 1862 * stranded TSN's waiting on stream reorder queues. Each stream 1863 * SHOULD only be reported once; this means that if multiple 1864 * abandoned messages occur in the same stream then only the 1865 * highest abandoned stream sequence number is reported. If the 1866 * total size of the FORWARD TSN does NOT fit in a single MTU then 1867 * the sender of the FORWARD TSN SHOULD lower the 1868 * Advanced.Peer.Ack.Point to the last TSN that will fit in a 1869 * single MTU. 1870 */ 1871 if (asoc->adv_peer_ack_point > ctsn) 1872 ftsn_chunk = sctp_make_fwdtsn(asoc, asoc->adv_peer_ack_point, 1873 nskips, &ftsn_skip_arr[0]); 1874 1875 if (ftsn_chunk) { 1876 list_add_tail(&ftsn_chunk->list, &q->control_chunk_list); 1877 SCTP_INC_STATS(sock_net(asoc->base.sk), SCTP_MIB_OUTCTRLCHUNKS); 1878 } 1879 } 1880