1 /* SCTP kernel implementation 2 * Copyright (c) 1999-2000 Cisco, Inc. 3 * Copyright (c) 1999-2001 Motorola, Inc. 4 * Copyright (c) 2001-2003 International Business Machines Corp. 5 * Copyright (c) 2001 Intel Corp. 6 * Copyright (c) 2001 La Monte H.P. Yarroll 7 * 8 * This file is part of the SCTP kernel implementation 9 * 10 * This module provides the abstraction for an SCTP tranport representing 11 * a remote transport address. For local transport addresses, we just use 12 * union sctp_addr. 13 * 14 * This SCTP implementation is free software; 15 * you can redistribute it and/or modify it under the terms of 16 * the GNU General Public License as published by 17 * the Free Software Foundation; either version 2, or (at your option) 18 * any later version. 19 * 20 * This SCTP implementation is distributed in the hope that it 21 * will be useful, but WITHOUT ANY WARRANTY; without even the implied 22 * ************************ 23 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 24 * See the GNU General Public License for more details. 25 * 26 * You should have received a copy of the GNU General Public License 27 * along with GNU CC; see the file COPYING. If not, write to 28 * the Free Software Foundation, 59 Temple Place - Suite 330, 29 * Boston, MA 02111-1307, USA. 30 * 31 * Please send any bug reports or fixes you make to the 32 * email address(es): 33 * lksctp developers <lksctp-developers@lists.sourceforge.net> 34 * 35 * Or submit a bug report through the following website: 36 * http://www.sf.net/projects/lksctp 37 * 38 * Written or modified by: 39 * La Monte H.P. Yarroll <piggy@acm.org> 40 * Karl Knutson <karl@athena.chicago.il.us> 41 * Jon Grimm <jgrimm@us.ibm.com> 42 * Xingang Guo <xingang.guo@intel.com> 43 * Hui Huang <hui.huang@nokia.com> 44 * Sridhar Samudrala <sri@us.ibm.com> 45 * Ardelle Fan <ardelle.fan@intel.com> 46 * 47 * Any bugs reported given to us we will try to fix... any fixes shared will 48 * be incorporated into the next SCTP release. 49 */ 50 51 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 52 53 #include <linux/slab.h> 54 #include <linux/types.h> 55 #include <linux/random.h> 56 #include <net/sctp/sctp.h> 57 #include <net/sctp/sm.h> 58 59 /* 1st Level Abstractions. */ 60 61 /* Initialize a new transport from provided memory. */ 62 static struct sctp_transport *sctp_transport_init(struct net *net, 63 struct sctp_transport *peer, 64 const union sctp_addr *addr, 65 gfp_t gfp) 66 { 67 /* Copy in the address. */ 68 peer->ipaddr = *addr; 69 peer->af_specific = sctp_get_af_specific(addr->sa.sa_family); 70 memset(&peer->saddr, 0, sizeof(union sctp_addr)); 71 72 peer->sack_generation = 0; 73 74 /* From 6.3.1 RTO Calculation: 75 * 76 * C1) Until an RTT measurement has been made for a packet sent to the 77 * given destination transport address, set RTO to the protocol 78 * parameter 'RTO.Initial'. 79 */ 80 peer->rto = msecs_to_jiffies(net->sctp.rto_initial); 81 82 peer->last_time_heard = jiffies; 83 peer->last_time_ecne_reduced = jiffies; 84 85 peer->param_flags = SPP_HB_DISABLE | 86 SPP_PMTUD_ENABLE | 87 SPP_SACKDELAY_ENABLE; 88 89 /* Initialize the default path max_retrans. */ 90 peer->pathmaxrxt = net->sctp.max_retrans_path; 91 peer->pf_retrans = net->sctp.pf_retrans; 92 93 INIT_LIST_HEAD(&peer->transmitted); 94 INIT_LIST_HEAD(&peer->send_ready); 95 INIT_LIST_HEAD(&peer->transports); 96 97 setup_timer(&peer->T3_rtx_timer, sctp_generate_t3_rtx_event, 98 (unsigned long)peer); 99 setup_timer(&peer->hb_timer, sctp_generate_heartbeat_event, 100 (unsigned long)peer); 101 setup_timer(&peer->proto_unreach_timer, 102 sctp_generate_proto_unreach_event, (unsigned long)peer); 103 104 /* Initialize the 64-bit random nonce sent with heartbeat. */ 105 get_random_bytes(&peer->hb_nonce, sizeof(peer->hb_nonce)); 106 107 atomic_set(&peer->refcnt, 1); 108 109 return peer; 110 } 111 112 /* Allocate and initialize a new transport. */ 113 struct sctp_transport *sctp_transport_new(struct net *net, 114 const union sctp_addr *addr, 115 gfp_t gfp) 116 { 117 struct sctp_transport *transport; 118 119 transport = kzalloc(sizeof(*transport), gfp); 120 if (!transport) 121 goto fail; 122 123 if (!sctp_transport_init(net, transport, addr, gfp)) 124 goto fail_init; 125 126 SCTP_DBG_OBJCNT_INC(transport); 127 128 return transport; 129 130 fail_init: 131 kfree(transport); 132 133 fail: 134 return NULL; 135 } 136 137 /* This transport is no longer needed. Free up if possible, or 138 * delay until it last reference count. 139 */ 140 void sctp_transport_free(struct sctp_transport *transport) 141 { 142 transport->dead = 1; 143 144 /* Try to delete the heartbeat timer. */ 145 if (del_timer(&transport->hb_timer)) 146 sctp_transport_put(transport); 147 148 /* Delete the T3_rtx timer if it's active. 149 * There is no point in not doing this now and letting 150 * structure hang around in memory since we know 151 * the tranport is going away. 152 */ 153 if (del_timer(&transport->T3_rtx_timer)) 154 sctp_transport_put(transport); 155 156 /* Delete the ICMP proto unreachable timer if it's active. */ 157 if (del_timer(&transport->proto_unreach_timer)) 158 sctp_association_put(transport->asoc); 159 160 sctp_transport_put(transport); 161 } 162 163 static void sctp_transport_destroy_rcu(struct rcu_head *head) 164 { 165 struct sctp_transport *transport; 166 167 transport = container_of(head, struct sctp_transport, rcu); 168 169 dst_release(transport->dst); 170 kfree(transport); 171 SCTP_DBG_OBJCNT_DEC(transport); 172 } 173 174 /* Destroy the transport data structure. 175 * Assumes there are no more users of this structure. 176 */ 177 static void sctp_transport_destroy(struct sctp_transport *transport) 178 { 179 if (unlikely(!transport->dead)) { 180 WARN(1, "Attempt to destroy undead transport %p!\n", transport); 181 return; 182 } 183 184 call_rcu(&transport->rcu, sctp_transport_destroy_rcu); 185 186 sctp_packet_free(&transport->packet); 187 188 if (transport->asoc) 189 sctp_association_put(transport->asoc); 190 } 191 192 /* Start T3_rtx timer if it is not already running and update the heartbeat 193 * timer. This routine is called every time a DATA chunk is sent. 194 */ 195 void sctp_transport_reset_timers(struct sctp_transport *transport) 196 { 197 /* RFC 2960 6.3.2 Retransmission Timer Rules 198 * 199 * R1) Every time a DATA chunk is sent to any address(including a 200 * retransmission), if the T3-rtx timer of that address is not running 201 * start it running so that it will expire after the RTO of that 202 * address. 203 */ 204 205 if (!timer_pending(&transport->T3_rtx_timer)) 206 if (!mod_timer(&transport->T3_rtx_timer, 207 jiffies + transport->rto)) 208 sctp_transport_hold(transport); 209 210 /* When a data chunk is sent, reset the heartbeat interval. */ 211 if (!mod_timer(&transport->hb_timer, 212 sctp_transport_timeout(transport))) 213 sctp_transport_hold(transport); 214 } 215 216 /* This transport has been assigned to an association. 217 * Initialize fields from the association or from the sock itself. 218 * Register the reference count in the association. 219 */ 220 void sctp_transport_set_owner(struct sctp_transport *transport, 221 struct sctp_association *asoc) 222 { 223 transport->asoc = asoc; 224 sctp_association_hold(asoc); 225 } 226 227 /* Initialize the pmtu of a transport. */ 228 void sctp_transport_pmtu(struct sctp_transport *transport, struct sock *sk) 229 { 230 /* If we don't have a fresh route, look one up */ 231 if (!transport->dst || transport->dst->obsolete) { 232 dst_release(transport->dst); 233 transport->af_specific->get_dst(transport, &transport->saddr, 234 &transport->fl, sk); 235 } 236 237 if (transport->dst) { 238 transport->pathmtu = dst_mtu(transport->dst); 239 } else 240 transport->pathmtu = SCTP_DEFAULT_MAXSEGMENT; 241 } 242 243 void sctp_transport_update_pmtu(struct sock *sk, struct sctp_transport *t, u32 pmtu) 244 { 245 struct dst_entry *dst; 246 247 if (unlikely(pmtu < SCTP_DEFAULT_MINSEGMENT)) { 248 pr_warn("%s: Reported pmtu %d too low, using default minimum of %d\n", 249 __func__, pmtu, 250 SCTP_DEFAULT_MINSEGMENT); 251 /* Use default minimum segment size and disable 252 * pmtu discovery on this transport. 253 */ 254 t->pathmtu = SCTP_DEFAULT_MINSEGMENT; 255 } else { 256 t->pathmtu = pmtu; 257 } 258 259 dst = sctp_transport_dst_check(t); 260 if (!dst) 261 t->af_specific->get_dst(t, &t->saddr, &t->fl, sk); 262 263 if (dst) { 264 dst->ops->update_pmtu(dst, sk, NULL, pmtu); 265 266 dst = sctp_transport_dst_check(t); 267 if (!dst) 268 t->af_specific->get_dst(t, &t->saddr, &t->fl, sk); 269 } 270 } 271 272 /* Caches the dst entry and source address for a transport's destination 273 * address. 274 */ 275 void sctp_transport_route(struct sctp_transport *transport, 276 union sctp_addr *saddr, struct sctp_sock *opt) 277 { 278 struct sctp_association *asoc = transport->asoc; 279 struct sctp_af *af = transport->af_specific; 280 281 af->get_dst(transport, saddr, &transport->fl, sctp_opt2sk(opt)); 282 283 if (saddr) 284 memcpy(&transport->saddr, saddr, sizeof(union sctp_addr)); 285 else 286 af->get_saddr(opt, transport, &transport->fl); 287 288 if ((transport->param_flags & SPP_PMTUD_DISABLE) && transport->pathmtu) { 289 return; 290 } 291 if (transport->dst) { 292 transport->pathmtu = dst_mtu(transport->dst); 293 294 /* Initialize sk->sk_rcv_saddr, if the transport is the 295 * association's active path for getsockname(). 296 */ 297 if (asoc && (!asoc->peer.primary_path || 298 (transport == asoc->peer.active_path))) 299 opt->pf->af->to_sk_saddr(&transport->saddr, 300 asoc->base.sk); 301 } else 302 transport->pathmtu = SCTP_DEFAULT_MAXSEGMENT; 303 } 304 305 /* Hold a reference to a transport. */ 306 void sctp_transport_hold(struct sctp_transport *transport) 307 { 308 atomic_inc(&transport->refcnt); 309 } 310 311 /* Release a reference to a transport and clean up 312 * if there are no more references. 313 */ 314 void sctp_transport_put(struct sctp_transport *transport) 315 { 316 if (atomic_dec_and_test(&transport->refcnt)) 317 sctp_transport_destroy(transport); 318 } 319 320 /* Update transport's RTO based on the newly calculated RTT. */ 321 void sctp_transport_update_rto(struct sctp_transport *tp, __u32 rtt) 322 { 323 if (unlikely(!tp->rto_pending)) 324 /* We should not be doing any RTO updates unless rto_pending is set. */ 325 pr_debug("%s: rto_pending not set on transport %p!\n", __func__, tp); 326 327 if (tp->rttvar || tp->srtt) { 328 struct net *net = sock_net(tp->asoc->base.sk); 329 /* 6.3.1 C3) When a new RTT measurement R' is made, set 330 * RTTVAR <- (1 - RTO.Beta) * RTTVAR + RTO.Beta * |SRTT - R'| 331 * SRTT <- (1 - RTO.Alpha) * SRTT + RTO.Alpha * R' 332 */ 333 334 /* Note: The above algorithm has been rewritten to 335 * express rto_beta and rto_alpha as inverse powers 336 * of two. 337 * For example, assuming the default value of RTO.Alpha of 338 * 1/8, rto_alpha would be expressed as 3. 339 */ 340 tp->rttvar = tp->rttvar - (tp->rttvar >> net->sctp.rto_beta) 341 + (((__u32)abs64((__s64)tp->srtt - (__s64)rtt)) >> net->sctp.rto_beta); 342 tp->srtt = tp->srtt - (tp->srtt >> net->sctp.rto_alpha) 343 + (rtt >> net->sctp.rto_alpha); 344 } else { 345 /* 6.3.1 C2) When the first RTT measurement R is made, set 346 * SRTT <- R, RTTVAR <- R/2. 347 */ 348 tp->srtt = rtt; 349 tp->rttvar = rtt >> 1; 350 } 351 352 /* 6.3.1 G1) Whenever RTTVAR is computed, if RTTVAR = 0, then 353 * adjust RTTVAR <- G, where G is the CLOCK GRANULARITY. 354 */ 355 if (tp->rttvar == 0) 356 tp->rttvar = SCTP_CLOCK_GRANULARITY; 357 358 /* 6.3.1 C3) After the computation, update RTO <- SRTT + 4 * RTTVAR. */ 359 tp->rto = tp->srtt + (tp->rttvar << 2); 360 361 /* 6.3.1 C6) Whenever RTO is computed, if it is less than RTO.Min 362 * seconds then it is rounded up to RTO.Min seconds. 363 */ 364 if (tp->rto < tp->asoc->rto_min) 365 tp->rto = tp->asoc->rto_min; 366 367 /* 6.3.1 C7) A maximum value may be placed on RTO provided it is 368 * at least RTO.max seconds. 369 */ 370 if (tp->rto > tp->asoc->rto_max) 371 tp->rto = tp->asoc->rto_max; 372 373 sctp_max_rto(tp->asoc, tp); 374 tp->rtt = rtt; 375 376 /* Reset rto_pending so that a new RTT measurement is started when a 377 * new data chunk is sent. 378 */ 379 tp->rto_pending = 0; 380 381 pr_debug("%s: transport:%p, rtt:%d, srtt:%d rttvar:%d, rto:%ld\n", 382 __func__, tp, rtt, tp->srtt, tp->rttvar, tp->rto); 383 } 384 385 /* This routine updates the transport's cwnd and partial_bytes_acked 386 * parameters based on the bytes acked in the received SACK. 387 */ 388 void sctp_transport_raise_cwnd(struct sctp_transport *transport, 389 __u32 sack_ctsn, __u32 bytes_acked) 390 { 391 struct sctp_association *asoc = transport->asoc; 392 __u32 cwnd, ssthresh, flight_size, pba, pmtu; 393 394 cwnd = transport->cwnd; 395 flight_size = transport->flight_size; 396 397 /* See if we need to exit Fast Recovery first */ 398 if (asoc->fast_recovery && 399 TSN_lte(asoc->fast_recovery_exit, sack_ctsn)) 400 asoc->fast_recovery = 0; 401 402 /* The appropriate cwnd increase algorithm is performed if, and only 403 * if the cumulative TSN whould advanced and the congestion window is 404 * being fully utilized. 405 */ 406 if (TSN_lte(sack_ctsn, transport->asoc->ctsn_ack_point) || 407 (flight_size < cwnd)) 408 return; 409 410 ssthresh = transport->ssthresh; 411 pba = transport->partial_bytes_acked; 412 pmtu = transport->asoc->pathmtu; 413 414 if (cwnd <= ssthresh) { 415 /* RFC 4960 7.2.1 416 * o When cwnd is less than or equal to ssthresh, an SCTP 417 * endpoint MUST use the slow-start algorithm to increase 418 * cwnd only if the current congestion window is being fully 419 * utilized, an incoming SACK advances the Cumulative TSN 420 * Ack Point, and the data sender is not in Fast Recovery. 421 * Only when these three conditions are met can the cwnd be 422 * increased; otherwise, the cwnd MUST not be increased. 423 * If these conditions are met, then cwnd MUST be increased 424 * by, at most, the lesser of 1) the total size of the 425 * previously outstanding DATA chunk(s) acknowledged, and 426 * 2) the destination's path MTU. This upper bound protects 427 * against the ACK-Splitting attack outlined in [SAVAGE99]. 428 */ 429 if (asoc->fast_recovery) 430 return; 431 432 if (bytes_acked > pmtu) 433 cwnd += pmtu; 434 else 435 cwnd += bytes_acked; 436 437 pr_debug("%s: slow start: transport:%p, bytes_acked:%d, " 438 "cwnd:%d, ssthresh:%d, flight_size:%d, pba:%d\n", 439 __func__, transport, bytes_acked, cwnd, ssthresh, 440 flight_size, pba); 441 } else { 442 /* RFC 2960 7.2.2 Whenever cwnd is greater than ssthresh, 443 * upon each SACK arrival that advances the Cumulative TSN Ack 444 * Point, increase partial_bytes_acked by the total number of 445 * bytes of all new chunks acknowledged in that SACK including 446 * chunks acknowledged by the new Cumulative TSN Ack and by 447 * Gap Ack Blocks. 448 * 449 * When partial_bytes_acked is equal to or greater than cwnd 450 * and before the arrival of the SACK the sender had cwnd or 451 * more bytes of data outstanding (i.e., before arrival of the 452 * SACK, flightsize was greater than or equal to cwnd), 453 * increase cwnd by MTU, and reset partial_bytes_acked to 454 * (partial_bytes_acked - cwnd). 455 */ 456 pba += bytes_acked; 457 if (pba >= cwnd) { 458 cwnd += pmtu; 459 pba = ((cwnd < pba) ? (pba - cwnd) : 0); 460 } 461 462 pr_debug("%s: congestion avoidance: transport:%p, " 463 "bytes_acked:%d, cwnd:%d, ssthresh:%d, " 464 "flight_size:%d, pba:%d\n", __func__, 465 transport, bytes_acked, cwnd, ssthresh, 466 flight_size, pba); 467 } 468 469 transport->cwnd = cwnd; 470 transport->partial_bytes_acked = pba; 471 } 472 473 /* This routine is used to lower the transport's cwnd when congestion is 474 * detected. 475 */ 476 void sctp_transport_lower_cwnd(struct sctp_transport *transport, 477 sctp_lower_cwnd_t reason) 478 { 479 struct sctp_association *asoc = transport->asoc; 480 481 switch (reason) { 482 case SCTP_LOWER_CWND_T3_RTX: 483 /* RFC 2960 Section 7.2.3, sctpimpguide 484 * When the T3-rtx timer expires on an address, SCTP should 485 * perform slow start by: 486 * ssthresh = max(cwnd/2, 4*MTU) 487 * cwnd = 1*MTU 488 * partial_bytes_acked = 0 489 */ 490 transport->ssthresh = max(transport->cwnd/2, 491 4*asoc->pathmtu); 492 transport->cwnd = asoc->pathmtu; 493 494 /* T3-rtx also clears fast recovery */ 495 asoc->fast_recovery = 0; 496 break; 497 498 case SCTP_LOWER_CWND_FAST_RTX: 499 /* RFC 2960 7.2.4 Adjust the ssthresh and cwnd of the 500 * destination address(es) to which the missing DATA chunks 501 * were last sent, according to the formula described in 502 * Section 7.2.3. 503 * 504 * RFC 2960 7.2.3, sctpimpguide Upon detection of packet 505 * losses from SACK (see Section 7.2.4), An endpoint 506 * should do the following: 507 * ssthresh = max(cwnd/2, 4*MTU) 508 * cwnd = ssthresh 509 * partial_bytes_acked = 0 510 */ 511 if (asoc->fast_recovery) 512 return; 513 514 /* Mark Fast recovery */ 515 asoc->fast_recovery = 1; 516 asoc->fast_recovery_exit = asoc->next_tsn - 1; 517 518 transport->ssthresh = max(transport->cwnd/2, 519 4*asoc->pathmtu); 520 transport->cwnd = transport->ssthresh; 521 break; 522 523 case SCTP_LOWER_CWND_ECNE: 524 /* RFC 2481 Section 6.1.2. 525 * If the sender receives an ECN-Echo ACK packet 526 * then the sender knows that congestion was encountered in the 527 * network on the path from the sender to the receiver. The 528 * indication of congestion should be treated just as a 529 * congestion loss in non-ECN Capable TCP. That is, the TCP 530 * source halves the congestion window "cwnd" and reduces the 531 * slow start threshold "ssthresh". 532 * A critical condition is that TCP does not react to 533 * congestion indications more than once every window of 534 * data (or more loosely more than once every round-trip time). 535 */ 536 if (time_after(jiffies, transport->last_time_ecne_reduced + 537 transport->rtt)) { 538 transport->ssthresh = max(transport->cwnd/2, 539 4*asoc->pathmtu); 540 transport->cwnd = transport->ssthresh; 541 transport->last_time_ecne_reduced = jiffies; 542 } 543 break; 544 545 case SCTP_LOWER_CWND_INACTIVE: 546 /* RFC 2960 Section 7.2.1, sctpimpguide 547 * When the endpoint does not transmit data on a given 548 * transport address, the cwnd of the transport address 549 * should be adjusted to max(cwnd/2, 4*MTU) per RTO. 550 * NOTE: Although the draft recommends that this check needs 551 * to be done every RTO interval, we do it every hearbeat 552 * interval. 553 */ 554 transport->cwnd = max(transport->cwnd/2, 555 4*asoc->pathmtu); 556 break; 557 } 558 559 transport->partial_bytes_acked = 0; 560 561 pr_debug("%s: transport:%p, reason:%d, cwnd:%d, ssthresh:%d\n", 562 __func__, transport, reason, transport->cwnd, 563 transport->ssthresh); 564 } 565 566 /* Apply Max.Burst limit to the congestion window: 567 * sctpimpguide-05 2.14.2 568 * D) When the time comes for the sender to 569 * transmit new DATA chunks, the protocol parameter Max.Burst MUST 570 * first be applied to limit how many new DATA chunks may be sent. 571 * The limit is applied by adjusting cwnd as follows: 572 * if ((flightsize+ Max.Burst * MTU) < cwnd) 573 * cwnd = flightsize + Max.Burst * MTU 574 */ 575 576 void sctp_transport_burst_limited(struct sctp_transport *t) 577 { 578 struct sctp_association *asoc = t->asoc; 579 u32 old_cwnd = t->cwnd; 580 u32 max_burst_bytes; 581 582 if (t->burst_limited) 583 return; 584 585 max_burst_bytes = t->flight_size + (asoc->max_burst * asoc->pathmtu); 586 if (max_burst_bytes < old_cwnd) { 587 t->cwnd = max_burst_bytes; 588 t->burst_limited = old_cwnd; 589 } 590 } 591 592 /* Restore the old cwnd congestion window, after the burst had it's 593 * desired effect. 594 */ 595 void sctp_transport_burst_reset(struct sctp_transport *t) 596 { 597 if (t->burst_limited) { 598 t->cwnd = t->burst_limited; 599 t->burst_limited = 0; 600 } 601 } 602 603 /* What is the next timeout value for this transport? */ 604 unsigned long sctp_transport_timeout(struct sctp_transport *t) 605 { 606 unsigned long timeout; 607 timeout = t->rto + sctp_jitter(t->rto); 608 if ((t->state != SCTP_UNCONFIRMED) && 609 (t->state != SCTP_PF)) 610 timeout += t->hbinterval; 611 timeout += jiffies; 612 return timeout; 613 } 614 615 /* Reset transport variables to their initial values */ 616 void sctp_transport_reset(struct sctp_transport *t) 617 { 618 struct sctp_association *asoc = t->asoc; 619 620 /* RFC 2960 (bis), Section 5.2.4 621 * All the congestion control parameters (e.g., cwnd, ssthresh) 622 * related to this peer MUST be reset to their initial values 623 * (see Section 6.2.1) 624 */ 625 t->cwnd = min(4*asoc->pathmtu, max_t(__u32, 2*asoc->pathmtu, 4380)); 626 t->burst_limited = 0; 627 t->ssthresh = asoc->peer.i.a_rwnd; 628 t->rto = asoc->rto_initial; 629 sctp_max_rto(asoc, t); 630 t->rtt = 0; 631 t->srtt = 0; 632 t->rttvar = 0; 633 634 /* Reset these additional varibles so that we have a clean 635 * slate. 636 */ 637 t->partial_bytes_acked = 0; 638 t->flight_size = 0; 639 t->error_count = 0; 640 t->rto_pending = 0; 641 t->hb_sent = 0; 642 643 /* Initialize the state information for SFR-CACC */ 644 t->cacc.changeover_active = 0; 645 t->cacc.cycling_changeover = 0; 646 t->cacc.next_tsn_at_change = 0; 647 t->cacc.cacc_saw_newack = 0; 648 } 649 650 /* Schedule retransmission on the given transport */ 651 void sctp_transport_immediate_rtx(struct sctp_transport *t) 652 { 653 /* Stop pending T3_rtx_timer */ 654 if (del_timer(&t->T3_rtx_timer)) 655 sctp_transport_put(t); 656 657 sctp_retransmit(&t->asoc->outqueue, t, SCTP_RTXR_T3_RTX); 658 if (!timer_pending(&t->T3_rtx_timer)) { 659 if (!mod_timer(&t->T3_rtx_timer, jiffies + t->rto)) 660 sctp_transport_hold(t); 661 } 662 return; 663 } 664