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 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 association. 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 * Jon Grimm <jgrimm@us.ibm.com> 36 * Xingang Guo <xingang.guo@intel.com> 37 * Hui Huang <hui.huang@nokia.com> 38 * Sridhar Samudrala <sri@us.ibm.com> 39 * Daisy Chang <daisyc@us.ibm.com> 40 * Ryan Layer <rmlayer@us.ibm.com> 41 * Kevin Gao <kevin.gao@intel.com> 42 */ 43 44#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 45 46#include <linux/types.h> 47#include <linux/fcntl.h> 48#include <linux/poll.h> 49#include <linux/init.h> 50 51#include <linux/slab.h> 52#include <linux/in.h> 53#include <net/ipv6.h> 54#include <net/sctp/sctp.h> 55#include <net/sctp/sm.h> 56 57/* Forward declarations for internal functions. */ 58static void sctp_select_active_and_retran_path(struct sctp_association *asoc); 59static void sctp_assoc_bh_rcv(struct work_struct *work); 60static void sctp_assoc_free_asconf_acks(struct sctp_association *asoc); 61static void sctp_assoc_free_asconf_queue(struct sctp_association *asoc); 62 63/* 1st Level Abstractions. */ 64 65/* Initialize a new association from provided memory. */ 66static struct sctp_association *sctp_association_init(struct sctp_association *asoc, 67 const struct sctp_endpoint *ep, 68 const struct sock *sk, 69 sctp_scope_t scope, 70 gfp_t gfp) 71{ 72 struct net *net = sock_net(sk); 73 struct sctp_sock *sp; 74 int i; 75 sctp_paramhdr_t *p; 76 int err; 77 78 /* Retrieve the SCTP per socket area. */ 79 sp = sctp_sk((struct sock *)sk); 80 81 /* Discarding const is appropriate here. */ 82 asoc->ep = (struct sctp_endpoint *)ep; 83 asoc->base.sk = (struct sock *)sk; 84 85 sctp_endpoint_hold(asoc->ep); 86 sock_hold(asoc->base.sk); 87 88 /* Initialize the common base substructure. */ 89 asoc->base.type = SCTP_EP_TYPE_ASSOCIATION; 90 91 /* Initialize the object handling fields. */ 92 atomic_set(&asoc->base.refcnt, 1); 93 94 /* Initialize the bind addr area. */ 95 sctp_bind_addr_init(&asoc->base.bind_addr, ep->base.bind_addr.port); 96 97 asoc->state = SCTP_STATE_CLOSED; 98 asoc->cookie_life = ms_to_ktime(sp->assocparams.sasoc_cookie_life); 99 asoc->user_frag = sp->user_frag; 100 101 /* Set the association max_retrans and RTO values from the 102 * socket values. 103 */ 104 asoc->max_retrans = sp->assocparams.sasoc_asocmaxrxt; 105 asoc->pf_retrans = net->sctp.pf_retrans; 106 107 asoc->rto_initial = msecs_to_jiffies(sp->rtoinfo.srto_initial); 108 asoc->rto_max = msecs_to_jiffies(sp->rtoinfo.srto_max); 109 asoc->rto_min = msecs_to_jiffies(sp->rtoinfo.srto_min); 110 111 /* Initialize the association's heartbeat interval based on the 112 * sock configured value. 113 */ 114 asoc->hbinterval = msecs_to_jiffies(sp->hbinterval); 115 116 /* Initialize path max retrans value. */ 117 asoc->pathmaxrxt = sp->pathmaxrxt; 118 119 /* Initialize default path MTU. */ 120 asoc->pathmtu = sp->pathmtu; 121 122 /* Set association default SACK delay */ 123 asoc->sackdelay = msecs_to_jiffies(sp->sackdelay); 124 asoc->sackfreq = sp->sackfreq; 125 126 /* Set the association default flags controlling 127 * Heartbeat, SACK delay, and Path MTU Discovery. 128 */ 129 asoc->param_flags = sp->param_flags; 130 131 /* Initialize the maximum number of new data packets that can be sent 132 * in a burst. 133 */ 134 asoc->max_burst = sp->max_burst; 135 136 /* initialize association timers */ 137 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] = asoc->rto_initial; 138 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] = asoc->rto_initial; 139 asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = asoc->rto_initial; 140 141 /* sctpimpguide Section 2.12.2 142 * If the 'T5-shutdown-guard' timer is used, it SHOULD be set to the 143 * recommended value of 5 times 'RTO.Max'. 144 */ 145 asoc->timeouts[SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD] 146 = 5 * asoc->rto_max; 147 148 asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] = asoc->sackdelay; 149 asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE] = sp->autoclose * HZ; 150 151 /* Initializes the timers */ 152 for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i) 153 setup_timer(&asoc->timers[i], sctp_timer_events[i], 154 (unsigned long)asoc); 155 156 /* Pull default initialization values from the sock options. 157 * Note: This assumes that the values have already been 158 * validated in the sock. 159 */ 160 asoc->c.sinit_max_instreams = sp->initmsg.sinit_max_instreams; 161 asoc->c.sinit_num_ostreams = sp->initmsg.sinit_num_ostreams; 162 asoc->max_init_attempts = sp->initmsg.sinit_max_attempts; 163 164 asoc->max_init_timeo = 165 msecs_to_jiffies(sp->initmsg.sinit_max_init_timeo); 166 167 /* Set the local window size for receive. 168 * This is also the rcvbuf space per association. 169 * RFC 6 - A SCTP receiver MUST be able to receive a minimum of 170 * 1500 bytes in one SCTP packet. 171 */ 172 if ((sk->sk_rcvbuf/2) < SCTP_DEFAULT_MINWINDOW) 173 asoc->rwnd = SCTP_DEFAULT_MINWINDOW; 174 else 175 asoc->rwnd = sk->sk_rcvbuf/2; 176 177 asoc->a_rwnd = asoc->rwnd; 178 179 /* Use my own max window until I learn something better. */ 180 asoc->peer.rwnd = SCTP_DEFAULT_MAXWINDOW; 181 182 /* Initialize the receive memory counter */ 183 atomic_set(&asoc->rmem_alloc, 0); 184 185 init_waitqueue_head(&asoc->wait); 186 187 asoc->c.my_vtag = sctp_generate_tag(ep); 188 asoc->c.my_port = ep->base.bind_addr.port; 189 190 asoc->c.initial_tsn = sctp_generate_tsn(ep); 191 192 asoc->next_tsn = asoc->c.initial_tsn; 193 194 asoc->ctsn_ack_point = asoc->next_tsn - 1; 195 asoc->adv_peer_ack_point = asoc->ctsn_ack_point; 196 asoc->highest_sacked = asoc->ctsn_ack_point; 197 asoc->last_cwr_tsn = asoc->ctsn_ack_point; 198 199 /* ADDIP Section 4.1 Asconf Chunk Procedures 200 * 201 * When an endpoint has an ASCONF signaled change to be sent to the 202 * remote endpoint it should do the following: 203 * ... 204 * A2) a serial number should be assigned to the chunk. The serial 205 * number SHOULD be a monotonically increasing number. The serial 206 * numbers SHOULD be initialized at the start of the 207 * association to the same value as the initial TSN. 208 */ 209 asoc->addip_serial = asoc->c.initial_tsn; 210 211 INIT_LIST_HEAD(&asoc->addip_chunk_list); 212 INIT_LIST_HEAD(&asoc->asconf_ack_list); 213 214 /* Make an empty list of remote transport addresses. */ 215 INIT_LIST_HEAD(&asoc->peer.transport_addr_list); 216 217 /* RFC 2960 5.1 Normal Establishment of an Association 218 * 219 * After the reception of the first data chunk in an 220 * association the endpoint must immediately respond with a 221 * sack to acknowledge the data chunk. Subsequent 222 * acknowledgements should be done as described in Section 223 * 6.2. 224 * 225 * [We implement this by telling a new association that it 226 * already received one packet.] 227 */ 228 asoc->peer.sack_needed = 1; 229 asoc->peer.sack_generation = 1; 230 231 /* Assume that the peer will tell us if he recognizes ASCONF 232 * as part of INIT exchange. 233 * The sctp_addip_noauth option is there for backward compatibility 234 * and will revert old behavior. 235 */ 236 if (net->sctp.addip_noauth) 237 asoc->peer.asconf_capable = 1; 238 239 /* Create an input queue. */ 240 sctp_inq_init(&asoc->base.inqueue); 241 sctp_inq_set_th_handler(&asoc->base.inqueue, sctp_assoc_bh_rcv); 242 243 /* Create an output queue. */ 244 sctp_outq_init(asoc, &asoc->outqueue); 245 246 if (!sctp_ulpq_init(&asoc->ulpq, asoc)) 247 goto fail_init; 248 249 /* Assume that peer would support both address types unless we are 250 * told otherwise. 251 */ 252 asoc->peer.ipv4_address = 1; 253 if (asoc->base.sk->sk_family == PF_INET6) 254 asoc->peer.ipv6_address = 1; 255 INIT_LIST_HEAD(&asoc->asocs); 256 257 asoc->default_stream = sp->default_stream; 258 asoc->default_ppid = sp->default_ppid; 259 asoc->default_flags = sp->default_flags; 260 asoc->default_context = sp->default_context; 261 asoc->default_timetolive = sp->default_timetolive; 262 asoc->default_rcv_context = sp->default_rcv_context; 263 264 /* AUTH related initializations */ 265 INIT_LIST_HEAD(&asoc->endpoint_shared_keys); 266 err = sctp_auth_asoc_copy_shkeys(ep, asoc, gfp); 267 if (err) 268 goto fail_init; 269 270 asoc->active_key_id = ep->active_key_id; 271 272 /* Save the hmacs and chunks list into this association */ 273 if (ep->auth_hmacs_list) 274 memcpy(asoc->c.auth_hmacs, ep->auth_hmacs_list, 275 ntohs(ep->auth_hmacs_list->param_hdr.length)); 276 if (ep->auth_chunk_list) 277 memcpy(asoc->c.auth_chunks, ep->auth_chunk_list, 278 ntohs(ep->auth_chunk_list->param_hdr.length)); 279 280 /* Get the AUTH random number for this association */ 281 p = (sctp_paramhdr_t *)asoc->c.auth_random; 282 p->type = SCTP_PARAM_RANDOM; 283 p->length = htons(sizeof(sctp_paramhdr_t) + SCTP_AUTH_RANDOM_LENGTH); 284 get_random_bytes(p+1, SCTP_AUTH_RANDOM_LENGTH); 285 286 return asoc; 287 288fail_init: 289 sock_put(asoc->base.sk); 290 sctp_endpoint_put(asoc->ep); 291 return NULL; 292} 293 294/* Allocate and initialize a new association */ 295struct sctp_association *sctp_association_new(const struct sctp_endpoint *ep, 296 const struct sock *sk, 297 sctp_scope_t scope, 298 gfp_t gfp) 299{ 300 struct sctp_association *asoc; 301 302 asoc = kzalloc(sizeof(*asoc), gfp); 303 if (!asoc) 304 goto fail; 305 306 if (!sctp_association_init(asoc, ep, sk, scope, gfp)) 307 goto fail_init; 308 309 SCTP_DBG_OBJCNT_INC(assoc); 310 311 pr_debug("Created asoc %p\n", asoc); 312 313 return asoc; 314 315fail_init: 316 kfree(asoc); 317fail: 318 return NULL; 319} 320 321/* Free this association if possible. There may still be users, so 322 * the actual deallocation may be delayed. 323 */ 324void sctp_association_free(struct sctp_association *asoc) 325{ 326 struct sock *sk = asoc->base.sk; 327 struct sctp_transport *transport; 328 struct list_head *pos, *temp; 329 int i; 330 331 /* Only real associations count against the endpoint, so 332 * don't bother for if this is a temporary association. 333 */ 334 if (!list_empty(&asoc->asocs)) { 335 list_del(&asoc->asocs); 336 337 /* Decrement the backlog value for a TCP-style listening 338 * socket. 339 */ 340 if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING)) 341 sk->sk_ack_backlog--; 342 } 343 344 /* Mark as dead, so other users can know this structure is 345 * going away. 346 */ 347 asoc->base.dead = true; 348 349 /* Dispose of any data lying around in the outqueue. */ 350 sctp_outq_free(&asoc->outqueue); 351 352 /* Dispose of any pending messages for the upper layer. */ 353 sctp_ulpq_free(&asoc->ulpq); 354 355 /* Dispose of any pending chunks on the inqueue. */ 356 sctp_inq_free(&asoc->base.inqueue); 357 358 sctp_tsnmap_free(&asoc->peer.tsn_map); 359 360 /* Free ssnmap storage. */ 361 sctp_ssnmap_free(asoc->ssnmap); 362 363 /* Clean up the bound address list. */ 364 sctp_bind_addr_free(&asoc->base.bind_addr); 365 366 /* Do we need to go through all of our timers and 367 * delete them? To be safe we will try to delete all, but we 368 * should be able to go through and make a guess based 369 * on our state. 370 */ 371 for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i) { 372 if (del_timer(&asoc->timers[i])) 373 sctp_association_put(asoc); 374 } 375 376 /* Free peer's cached cookie. */ 377 kfree(asoc->peer.cookie); 378 kfree(asoc->peer.peer_random); 379 kfree(asoc->peer.peer_chunks); 380 kfree(asoc->peer.peer_hmacs); 381 382 /* Release the transport structures. */ 383 list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) { 384 transport = list_entry(pos, struct sctp_transport, transports); 385 list_del_rcu(pos); 386 sctp_transport_free(transport); 387 } 388 389 asoc->peer.transport_count = 0; 390 391 sctp_asconf_queue_teardown(asoc); 392 393 /* Free pending address space being deleted */ 394 kfree(asoc->asconf_addr_del_pending); 395 396 /* AUTH - Free the endpoint shared keys */ 397 sctp_auth_destroy_keys(&asoc->endpoint_shared_keys); 398 399 /* AUTH - Free the association shared key */ 400 sctp_auth_key_put(asoc->asoc_shared_key); 401 402 sctp_association_put(asoc); 403} 404 405/* Cleanup and free up an association. */ 406static void sctp_association_destroy(struct sctp_association *asoc) 407{ 408 if (unlikely(!asoc->base.dead)) { 409 WARN(1, "Attempt to destroy undead association %p!\n", asoc); 410 return; 411 } 412 413 sctp_endpoint_put(asoc->ep); 414 sock_put(asoc->base.sk); 415 416 if (asoc->assoc_id != 0) { 417 spin_lock_bh(&sctp_assocs_id_lock); 418 idr_remove(&sctp_assocs_id, asoc->assoc_id); 419 spin_unlock_bh(&sctp_assocs_id_lock); 420 } 421 422 WARN_ON(atomic_read(&asoc->rmem_alloc)); 423 424 kfree(asoc); 425 SCTP_DBG_OBJCNT_DEC(assoc); 426} 427 428/* Change the primary destination address for the peer. */ 429void sctp_assoc_set_primary(struct sctp_association *asoc, 430 struct sctp_transport *transport) 431{ 432 int changeover = 0; 433 434 /* it's a changeover only if we already have a primary path 435 * that we are changing 436 */ 437 if (asoc->peer.primary_path != NULL && 438 asoc->peer.primary_path != transport) 439 changeover = 1 ; 440 441 asoc->peer.primary_path = transport; 442 443 /* Set a default msg_name for events. */ 444 memcpy(&asoc->peer.primary_addr, &transport->ipaddr, 445 sizeof(union sctp_addr)); 446 447 /* If the primary path is changing, assume that the 448 * user wants to use this new path. 449 */ 450 if ((transport->state == SCTP_ACTIVE) || 451 (transport->state == SCTP_UNKNOWN)) 452 asoc->peer.active_path = transport; 453 454 /* 455 * SFR-CACC algorithm: 456 * Upon the receipt of a request to change the primary 457 * destination address, on the data structure for the new 458 * primary destination, the sender MUST do the following: 459 * 460 * 1) If CHANGEOVER_ACTIVE is set, then there was a switch 461 * to this destination address earlier. The sender MUST set 462 * CYCLING_CHANGEOVER to indicate that this switch is a 463 * double switch to the same destination address. 464 * 465 * Really, only bother is we have data queued or outstanding on 466 * the association. 467 */ 468 if (!asoc->outqueue.outstanding_bytes && !asoc->outqueue.out_qlen) 469 return; 470 471 if (transport->cacc.changeover_active) 472 transport->cacc.cycling_changeover = changeover; 473 474 /* 2) The sender MUST set CHANGEOVER_ACTIVE to indicate that 475 * a changeover has occurred. 476 */ 477 transport->cacc.changeover_active = changeover; 478 479 /* 3) The sender MUST store the next TSN to be sent in 480 * next_tsn_at_change. 481 */ 482 transport->cacc.next_tsn_at_change = asoc->next_tsn; 483} 484 485/* Remove a transport from an association. */ 486void sctp_assoc_rm_peer(struct sctp_association *asoc, 487 struct sctp_transport *peer) 488{ 489 struct list_head *pos; 490 struct sctp_transport *transport; 491 492 pr_debug("%s: association:%p addr:%pISpc\n", 493 __func__, asoc, &peer->ipaddr.sa); 494 495 /* If we are to remove the current retran_path, update it 496 * to the next peer before removing this peer from the list. 497 */ 498 if (asoc->peer.retran_path == peer) 499 sctp_assoc_update_retran_path(asoc); 500 501 /* Remove this peer from the list. */ 502 list_del_rcu(&peer->transports); 503 504 /* Get the first transport of asoc. */ 505 pos = asoc->peer.transport_addr_list.next; 506 transport = list_entry(pos, struct sctp_transport, transports); 507 508 /* Update any entries that match the peer to be deleted. */ 509 if (asoc->peer.primary_path == peer) 510 sctp_assoc_set_primary(asoc, transport); 511 if (asoc->peer.active_path == peer) 512 asoc->peer.active_path = transport; 513 if (asoc->peer.retran_path == peer) 514 asoc->peer.retran_path = transport; 515 if (asoc->peer.last_data_from == peer) 516 asoc->peer.last_data_from = transport; 517 518 /* If we remove the transport an INIT was last sent to, set it to 519 * NULL. Combined with the update of the retran path above, this 520 * will cause the next INIT to be sent to the next available 521 * transport, maintaining the cycle. 522 */ 523 if (asoc->init_last_sent_to == peer) 524 asoc->init_last_sent_to = NULL; 525 526 /* If we remove the transport an SHUTDOWN was last sent to, set it 527 * to NULL. Combined with the update of the retran path above, this 528 * will cause the next SHUTDOWN to be sent to the next available 529 * transport, maintaining the cycle. 530 */ 531 if (asoc->shutdown_last_sent_to == peer) 532 asoc->shutdown_last_sent_to = NULL; 533 534 /* If we remove the transport an ASCONF was last sent to, set it to 535 * NULL. 536 */ 537 if (asoc->addip_last_asconf && 538 asoc->addip_last_asconf->transport == peer) 539 asoc->addip_last_asconf->transport = NULL; 540 541 /* If we have something on the transmitted list, we have to 542 * save it off. The best place is the active path. 543 */ 544 if (!list_empty(&peer->transmitted)) { 545 struct sctp_transport *active = asoc->peer.active_path; 546 struct sctp_chunk *ch; 547 548 /* Reset the transport of each chunk on this list */ 549 list_for_each_entry(ch, &peer->transmitted, 550 transmitted_list) { 551 ch->transport = NULL; 552 ch->rtt_in_progress = 0; 553 } 554 555 list_splice_tail_init(&peer->transmitted, 556 &active->transmitted); 557 558 /* Start a T3 timer here in case it wasn't running so 559 * that these migrated packets have a chance to get 560 * retransmitted. 561 */ 562 if (!timer_pending(&active->T3_rtx_timer)) 563 if (!mod_timer(&active->T3_rtx_timer, 564 jiffies + active->rto)) 565 sctp_transport_hold(active); 566 } 567 568 asoc->peer.transport_count--; 569 570 sctp_transport_free(peer); 571} 572 573/* Add a transport address to an association. */ 574struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *asoc, 575 const union sctp_addr *addr, 576 const gfp_t gfp, 577 const int peer_state) 578{ 579 struct net *net = sock_net(asoc->base.sk); 580 struct sctp_transport *peer; 581 struct sctp_sock *sp; 582 unsigned short port; 583 584 sp = sctp_sk(asoc->base.sk); 585 586 /* AF_INET and AF_INET6 share common port field. */ 587 port = ntohs(addr->v4.sin_port); 588 589 pr_debug("%s: association:%p addr:%pISpc state:%d\n", __func__, 590 asoc, &addr->sa, peer_state); 591 592 /* Set the port if it has not been set yet. */ 593 if (0 == asoc->peer.port) 594 asoc->peer.port = port; 595 596 /* Check to see if this is a duplicate. */ 597 peer = sctp_assoc_lookup_paddr(asoc, addr); 598 if (peer) { 599 /* An UNKNOWN state is only set on transports added by 600 * user in sctp_connectx() call. Such transports should be 601 * considered CONFIRMED per RFC 4960, Section 5.4. 602 */ 603 if (peer->state == SCTP_UNKNOWN) { 604 peer->state = SCTP_ACTIVE; 605 } 606 return peer; 607 } 608 609 peer = sctp_transport_new(net, addr, gfp); 610 if (!peer) 611 return NULL; 612 613 sctp_transport_set_owner(peer, asoc); 614 615 /* Initialize the peer's heartbeat interval based on the 616 * association configured value. 617 */ 618 peer->hbinterval = asoc->hbinterval; 619 620 /* Set the path max_retrans. */ 621 peer->pathmaxrxt = asoc->pathmaxrxt; 622 623 /* And the partial failure retrans threshold */ 624 peer->pf_retrans = asoc->pf_retrans; 625 626 /* Initialize the peer's SACK delay timeout based on the 627 * association configured value. 628 */ 629 peer->sackdelay = asoc->sackdelay; 630 peer->sackfreq = asoc->sackfreq; 631 632 /* Enable/disable heartbeat, SACK delay, and path MTU discovery 633 * based on association setting. 634 */ 635 peer->param_flags = asoc->param_flags; 636 637 sctp_transport_route(peer, NULL, sp); 638 639 /* Initialize the pmtu of the transport. */ 640 if (peer->param_flags & SPP_PMTUD_DISABLE) { 641 if (asoc->pathmtu) 642 peer->pathmtu = asoc->pathmtu; 643 else 644 peer->pathmtu = SCTP_DEFAULT_MAXSEGMENT; 645 } 646 647 /* If this is the first transport addr on this association, 648 * initialize the association PMTU to the peer's PMTU. 649 * If not and the current association PMTU is higher than the new 650 * peer's PMTU, reset the association PMTU to the new peer's PMTU. 651 */ 652 if (asoc->pathmtu) 653 asoc->pathmtu = min_t(int, peer->pathmtu, asoc->pathmtu); 654 else 655 asoc->pathmtu = peer->pathmtu; 656 657 pr_debug("%s: association:%p PMTU set to %d\n", __func__, asoc, 658 asoc->pathmtu); 659 660 peer->pmtu_pending = 0; 661 662 asoc->frag_point = sctp_frag_point(asoc, asoc->pathmtu); 663 664 /* The asoc->peer.port might not be meaningful yet, but 665 * initialize the packet structure anyway. 666 */ 667 sctp_packet_init(&peer->packet, peer, asoc->base.bind_addr.port, 668 asoc->peer.port); 669 670 /* 7.2.1 Slow-Start 671 * 672 * o The initial cwnd before DATA transmission or after a sufficiently 673 * long idle period MUST be set to 674 * min(4*MTU, max(2*MTU, 4380 bytes)) 675 * 676 * o The initial value of ssthresh MAY be arbitrarily high 677 * (for example, implementations MAY use the size of the 678 * receiver advertised window). 679 */ 680 peer->cwnd = min(4*asoc->pathmtu, max_t(__u32, 2*asoc->pathmtu, 4380)); 681 682 /* At this point, we may not have the receiver's advertised window, 683 * so initialize ssthresh to the default value and it will be set 684 * later when we process the INIT. 685 */ 686 peer->ssthresh = SCTP_DEFAULT_MAXWINDOW; 687 688 peer->partial_bytes_acked = 0; 689 peer->flight_size = 0; 690 peer->burst_limited = 0; 691 692 /* Set the transport's RTO.initial value */ 693 peer->rto = asoc->rto_initial; 694 sctp_max_rto(asoc, peer); 695 696 /* Set the peer's active state. */ 697 peer->state = peer_state; 698 699 /* Attach the remote transport to our asoc. */ 700 list_add_tail_rcu(&peer->transports, &asoc->peer.transport_addr_list); 701 asoc->peer.transport_count++; 702 703 /* If we do not yet have a primary path, set one. */ 704 if (!asoc->peer.primary_path) { 705 sctp_assoc_set_primary(asoc, peer); 706 asoc->peer.retran_path = peer; 707 } 708 709 if (asoc->peer.active_path == asoc->peer.retran_path && 710 peer->state != SCTP_UNCONFIRMED) { 711 asoc->peer.retran_path = peer; 712 } 713 714 return peer; 715} 716 717/* Delete a transport address from an association. */ 718void sctp_assoc_del_peer(struct sctp_association *asoc, 719 const union sctp_addr *addr) 720{ 721 struct list_head *pos; 722 struct list_head *temp; 723 struct sctp_transport *transport; 724 725 list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) { 726 transport = list_entry(pos, struct sctp_transport, transports); 727 if (sctp_cmp_addr_exact(addr, &transport->ipaddr)) { 728 /* Do book keeping for removing the peer and free it. */ 729 sctp_assoc_rm_peer(asoc, transport); 730 break; 731 } 732 } 733} 734 735/* Lookup a transport by address. */ 736struct sctp_transport *sctp_assoc_lookup_paddr( 737 const struct sctp_association *asoc, 738 const union sctp_addr *address) 739{ 740 struct sctp_transport *t; 741 742 /* Cycle through all transports searching for a peer address. */ 743 744 list_for_each_entry(t, &asoc->peer.transport_addr_list, 745 transports) { 746 if (sctp_cmp_addr_exact(address, &t->ipaddr)) 747 return t; 748 } 749 750 return NULL; 751} 752 753/* Remove all transports except a give one */ 754void sctp_assoc_del_nonprimary_peers(struct sctp_association *asoc, 755 struct sctp_transport *primary) 756{ 757 struct sctp_transport *temp; 758 struct sctp_transport *t; 759 760 list_for_each_entry_safe(t, temp, &asoc->peer.transport_addr_list, 761 transports) { 762 /* if the current transport is not the primary one, delete it */ 763 if (t != primary) 764 sctp_assoc_rm_peer(asoc, t); 765 } 766} 767 768/* Engage in transport control operations. 769 * Mark the transport up or down and send a notification to the user. 770 * Select and update the new active and retran paths. 771 */ 772void sctp_assoc_control_transport(struct sctp_association *asoc, 773 struct sctp_transport *transport, 774 sctp_transport_cmd_t command, 775 sctp_sn_error_t error) 776{ 777 struct sctp_ulpevent *event; 778 struct sockaddr_storage addr; 779 int spc_state = 0; 780 bool ulp_notify = true; 781 782 /* Record the transition on the transport. */ 783 switch (command) { 784 case SCTP_TRANSPORT_UP: 785 /* If we are moving from UNCONFIRMED state due 786 * to heartbeat success, report the SCTP_ADDR_CONFIRMED 787 * state to the user, otherwise report SCTP_ADDR_AVAILABLE. 788 */ 789 if (SCTP_UNCONFIRMED == transport->state && 790 SCTP_HEARTBEAT_SUCCESS == error) 791 spc_state = SCTP_ADDR_CONFIRMED; 792 else 793 spc_state = SCTP_ADDR_AVAILABLE; 794 /* Don't inform ULP about transition from PF to 795 * active state and set cwnd to 1 MTU, see SCTP 796 * Quick failover draft section 5.1, point 5 797 */ 798 if (transport->state == SCTP_PF) { 799 ulp_notify = false; 800 transport->cwnd = asoc->pathmtu; 801 } 802 transport->state = SCTP_ACTIVE; 803 break; 804 805 case SCTP_TRANSPORT_DOWN: 806 /* If the transport was never confirmed, do not transition it 807 * to inactive state. Also, release the cached route since 808 * there may be a better route next time. 809 */ 810 if (transport->state != SCTP_UNCONFIRMED) 811 transport->state = SCTP_INACTIVE; 812 else { 813 dst_release(transport->dst); 814 transport->dst = NULL; 815 ulp_notify = false; 816 } 817 818 spc_state = SCTP_ADDR_UNREACHABLE; 819 break; 820 821 case SCTP_TRANSPORT_PF: 822 transport->state = SCTP_PF; 823 ulp_notify = false; 824 break; 825 826 default: 827 return; 828 } 829 830 /* Generate and send a SCTP_PEER_ADDR_CHANGE notification 831 * to the user. 832 */ 833 if (ulp_notify) { 834 memset(&addr, 0, sizeof(struct sockaddr_storage)); 835 memcpy(&addr, &transport->ipaddr, 836 transport->af_specific->sockaddr_len); 837 838 event = sctp_ulpevent_make_peer_addr_change(asoc, &addr, 839 0, spc_state, error, GFP_ATOMIC); 840 if (event) 841 sctp_ulpq_tail_event(&asoc->ulpq, event); 842 } 843 844 /* Select new active and retran paths. */ 845 sctp_select_active_and_retran_path(asoc); 846} 847 848/* Hold a reference to an association. */ 849void sctp_association_hold(struct sctp_association *asoc) 850{ 851 atomic_inc(&asoc->base.refcnt); 852} 853 854/* Release a reference to an association and cleanup 855 * if there are no more references. 856 */ 857void sctp_association_put(struct sctp_association *asoc) 858{ 859 if (atomic_dec_and_test(&asoc->base.refcnt)) 860 sctp_association_destroy(asoc); 861} 862 863/* Allocate the next TSN, Transmission Sequence Number, for the given 864 * association. 865 */ 866__u32 sctp_association_get_next_tsn(struct sctp_association *asoc) 867{ 868 /* From Section 1.6 Serial Number Arithmetic: 869 * Transmission Sequence Numbers wrap around when they reach 870 * 2**32 - 1. That is, the next TSN a DATA chunk MUST use 871 * after transmitting TSN = 2*32 - 1 is TSN = 0. 872 */ 873 __u32 retval = asoc->next_tsn; 874 asoc->next_tsn++; 875 asoc->unack_data++; 876 877 return retval; 878} 879 880/* Compare two addresses to see if they match. Wildcard addresses 881 * only match themselves. 882 */ 883int sctp_cmp_addr_exact(const union sctp_addr *ss1, 884 const union sctp_addr *ss2) 885{ 886 struct sctp_af *af; 887 888 af = sctp_get_af_specific(ss1->sa.sa_family); 889 if (unlikely(!af)) 890 return 0; 891 892 return af->cmp_addr(ss1, ss2); 893} 894 895/* Return an ecne chunk to get prepended to a packet. 896 * Note: We are sly and return a shared, prealloced chunk. FIXME: 897 * No we don't, but we could/should. 898 */ 899struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc) 900{ 901 if (!asoc->need_ecne) 902 return NULL; 903 904 /* Send ECNE if needed. 905 * Not being able to allocate a chunk here is not deadly. 906 */ 907 return sctp_make_ecne(asoc, asoc->last_ecne_tsn); 908} 909 910/* 911 * Find which transport this TSN was sent on. 912 */ 913struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *asoc, 914 __u32 tsn) 915{ 916 struct sctp_transport *active; 917 struct sctp_transport *match; 918 struct sctp_transport *transport; 919 struct sctp_chunk *chunk; 920 __be32 key = htonl(tsn); 921 922 match = NULL; 923 924 /* 925 * FIXME: In general, find a more efficient data structure for 926 * searching. 927 */ 928 929 /* 930 * The general strategy is to search each transport's transmitted 931 * list. Return which transport this TSN lives on. 932 * 933 * Let's be hopeful and check the active_path first. 934 * Another optimization would be to know if there is only one 935 * outbound path and not have to look for the TSN at all. 936 * 937 */ 938 939 active = asoc->peer.active_path; 940 941 list_for_each_entry(chunk, &active->transmitted, 942 transmitted_list) { 943 944 if (key == chunk->subh.data_hdr->tsn) { 945 match = active; 946 goto out; 947 } 948 } 949 950 /* If not found, go search all the other transports. */ 951 list_for_each_entry(transport, &asoc->peer.transport_addr_list, 952 transports) { 953 954 if (transport == active) 955 continue; 956 list_for_each_entry(chunk, &transport->transmitted, 957 transmitted_list) { 958 if (key == chunk->subh.data_hdr->tsn) { 959 match = transport; 960 goto out; 961 } 962 } 963 } 964out: 965 return match; 966} 967 968/* Is this the association we are looking for? */ 969struct sctp_transport *sctp_assoc_is_match(struct sctp_association *asoc, 970 struct net *net, 971 const union sctp_addr *laddr, 972 const union sctp_addr *paddr) 973{ 974 struct sctp_transport *transport; 975 976 if ((htons(asoc->base.bind_addr.port) == laddr->v4.sin_port) && 977 (htons(asoc->peer.port) == paddr->v4.sin_port) && 978 net_eq(sock_net(asoc->base.sk), net)) { 979 transport = sctp_assoc_lookup_paddr(asoc, paddr); 980 if (!transport) 981 goto out; 982 983 if (sctp_bind_addr_match(&asoc->base.bind_addr, laddr, 984 sctp_sk(asoc->base.sk))) 985 goto out; 986 } 987 transport = NULL; 988 989out: 990 return transport; 991} 992 993/* Do delayed input processing. This is scheduled by sctp_rcv(). */ 994static void sctp_assoc_bh_rcv(struct work_struct *work) 995{ 996 struct sctp_association *asoc = 997 container_of(work, struct sctp_association, 998 base.inqueue.immediate); 999 struct net *net = sock_net(asoc->base.sk); 1000 struct sctp_endpoint *ep; 1001 struct sctp_chunk *chunk; 1002 struct sctp_inq *inqueue; 1003 int state; 1004 sctp_subtype_t subtype; 1005 int error = 0; 1006 1007 /* The association should be held so we should be safe. */ 1008 ep = asoc->ep; 1009 1010 inqueue = &asoc->base.inqueue; 1011 sctp_association_hold(asoc); 1012 while (NULL != (chunk = sctp_inq_pop(inqueue))) { 1013 state = asoc->state; 1014 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type); 1015 1016 /* SCTP-AUTH, Section 6.3: 1017 * The receiver has a list of chunk types which it expects 1018 * to be received only after an AUTH-chunk. This list has 1019 * been sent to the peer during the association setup. It 1020 * MUST silently discard these chunks if they are not placed 1021 * after an AUTH chunk in the packet. 1022 */ 1023 if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth) 1024 continue; 1025 1026 /* Remember where the last DATA chunk came from so we 1027 * know where to send the SACK. 1028 */ 1029 if (sctp_chunk_is_data(chunk)) 1030 asoc->peer.last_data_from = chunk->transport; 1031 else { 1032 SCTP_INC_STATS(net, SCTP_MIB_INCTRLCHUNKS); 1033 asoc->stats.ictrlchunks++; 1034 if (chunk->chunk_hdr->type == SCTP_CID_SACK) 1035 asoc->stats.isacks++; 1036 } 1037 1038 if (chunk->transport) 1039 chunk->transport->last_time_heard = ktime_get(); 1040 1041 /* Run through the state machine. */ 1042 error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, 1043 state, ep, asoc, chunk, GFP_ATOMIC); 1044 1045 /* Check to see if the association is freed in response to 1046 * the incoming chunk. If so, get out of the while loop. 1047 */ 1048 if (asoc->base.dead) 1049 break; 1050 1051 /* If there is an error on chunk, discard this packet. */ 1052 if (error && chunk) 1053 chunk->pdiscard = 1; 1054 } 1055 sctp_association_put(asoc); 1056} 1057 1058/* This routine moves an association from its old sk to a new sk. */ 1059void sctp_assoc_migrate(struct sctp_association *assoc, struct sock *newsk) 1060{ 1061 struct sctp_sock *newsp = sctp_sk(newsk); 1062 struct sock *oldsk = assoc->base.sk; 1063 1064 /* Delete the association from the old endpoint's list of 1065 * associations. 1066 */ 1067 list_del_init(&assoc->asocs); 1068 1069 /* Decrement the backlog value for a TCP-style socket. */ 1070 if (sctp_style(oldsk, TCP)) 1071 oldsk->sk_ack_backlog--; 1072 1073 /* Release references to the old endpoint and the sock. */ 1074 sctp_endpoint_put(assoc->ep); 1075 sock_put(assoc->base.sk); 1076 1077 /* Get a reference to the new endpoint. */ 1078 assoc->ep = newsp->ep; 1079 sctp_endpoint_hold(assoc->ep); 1080 1081 /* Get a reference to the new sock. */ 1082 assoc->base.sk = newsk; 1083 sock_hold(assoc->base.sk); 1084 1085 /* Add the association to the new endpoint's list of associations. */ 1086 sctp_endpoint_add_asoc(newsp->ep, assoc); 1087} 1088 1089/* Update an association (possibly from unexpected COOKIE-ECHO processing). */ 1090void sctp_assoc_update(struct sctp_association *asoc, 1091 struct sctp_association *new) 1092{ 1093 struct sctp_transport *trans; 1094 struct list_head *pos, *temp; 1095 1096 /* Copy in new parameters of peer. */ 1097 asoc->c = new->c; 1098 asoc->peer.rwnd = new->peer.rwnd; 1099 asoc->peer.sack_needed = new->peer.sack_needed; 1100 asoc->peer.auth_capable = new->peer.auth_capable; 1101 asoc->peer.i = new->peer.i; 1102 sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL, 1103 asoc->peer.i.initial_tsn, GFP_ATOMIC); 1104 1105 /* Remove any peer addresses not present in the new association. */ 1106 list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) { 1107 trans = list_entry(pos, struct sctp_transport, transports); 1108 if (!sctp_assoc_lookup_paddr(new, &trans->ipaddr)) { 1109 sctp_assoc_rm_peer(asoc, trans); 1110 continue; 1111 } 1112 1113 if (asoc->state >= SCTP_STATE_ESTABLISHED) 1114 sctp_transport_reset(trans); 1115 } 1116 1117 /* If the case is A (association restart), use 1118 * initial_tsn as next_tsn. If the case is B, use 1119 * current next_tsn in case data sent to peer 1120 * has been discarded and needs retransmission. 1121 */ 1122 if (asoc->state >= SCTP_STATE_ESTABLISHED) { 1123 asoc->next_tsn = new->next_tsn; 1124 asoc->ctsn_ack_point = new->ctsn_ack_point; 1125 asoc->adv_peer_ack_point = new->adv_peer_ack_point; 1126 1127 /* Reinitialize SSN for both local streams 1128 * and peer's streams. 1129 */ 1130 sctp_ssnmap_clear(asoc->ssnmap); 1131 1132 /* Flush the ULP reassembly and ordered queue. 1133 * Any data there will now be stale and will 1134 * cause problems. 1135 */ 1136 sctp_ulpq_flush(&asoc->ulpq); 1137 1138 /* reset the overall association error count so 1139 * that the restarted association doesn't get torn 1140 * down on the next retransmission timer. 1141 */ 1142 asoc->overall_error_count = 0; 1143 1144 } else { 1145 /* Add any peer addresses from the new association. */ 1146 list_for_each_entry(trans, &new->peer.transport_addr_list, 1147 transports) { 1148 if (!sctp_assoc_lookup_paddr(asoc, &trans->ipaddr)) 1149 sctp_assoc_add_peer(asoc, &trans->ipaddr, 1150 GFP_ATOMIC, trans->state); 1151 } 1152 1153 asoc->ctsn_ack_point = asoc->next_tsn - 1; 1154 asoc->adv_peer_ack_point = asoc->ctsn_ack_point; 1155 if (!asoc->ssnmap) { 1156 /* Move the ssnmap. */ 1157 asoc->ssnmap = new->ssnmap; 1158 new->ssnmap = NULL; 1159 } 1160 1161 if (!asoc->assoc_id) { 1162 /* get a new association id since we don't have one 1163 * yet. 1164 */ 1165 sctp_assoc_set_id(asoc, GFP_ATOMIC); 1166 } 1167 } 1168 1169 /* SCTP-AUTH: Save the peer parameters from the new associations 1170 * and also move the association shared keys over 1171 */ 1172 kfree(asoc->peer.peer_random); 1173 asoc->peer.peer_random = new->peer.peer_random; 1174 new->peer.peer_random = NULL; 1175 1176 kfree(asoc->peer.peer_chunks); 1177 asoc->peer.peer_chunks = new->peer.peer_chunks; 1178 new->peer.peer_chunks = NULL; 1179 1180 kfree(asoc->peer.peer_hmacs); 1181 asoc->peer.peer_hmacs = new->peer.peer_hmacs; 1182 new->peer.peer_hmacs = NULL; 1183 1184 sctp_auth_asoc_init_active_key(asoc, GFP_ATOMIC); 1185} 1186 1187/* Update the retran path for sending a retransmitted packet. 1188 * See also RFC4960, 6.4. Multi-Homed SCTP Endpoints: 1189 * 1190 * When there is outbound data to send and the primary path 1191 * becomes inactive (e.g., due to failures), or where the 1192 * SCTP user explicitly requests to send data to an 1193 * inactive destination transport address, before reporting 1194 * an error to its ULP, the SCTP endpoint should try to send 1195 * the data to an alternate active destination transport 1196 * address if one exists. 1197 * 1198 * When retransmitting data that timed out, if the endpoint 1199 * is multihomed, it should consider each source-destination 1200 * address pair in its retransmission selection policy. 1201 * When retransmitting timed-out data, the endpoint should 1202 * attempt to pick the most divergent source-destination 1203 * pair from the original source-destination pair to which 1204 * the packet was transmitted. 1205 * 1206 * Note: Rules for picking the most divergent source-destination 1207 * pair are an implementation decision and are not specified 1208 * within this document. 1209 * 1210 * Our basic strategy is to round-robin transports in priorities 1211 * according to sctp_state_prio_map[] e.g., if no such 1212 * transport with state SCTP_ACTIVE exists, round-robin through 1213 * SCTP_UNKNOWN, etc. You get the picture. 1214 */ 1215static const u8 sctp_trans_state_to_prio_map[] = { 1216 [SCTP_ACTIVE] = 3, /* best case */ 1217 [SCTP_UNKNOWN] = 2, 1218 [SCTP_PF] = 1, 1219 [SCTP_INACTIVE] = 0, /* worst case */ 1220}; 1221 1222static u8 sctp_trans_score(const struct sctp_transport *trans) 1223{ 1224 return sctp_trans_state_to_prio_map[trans->state]; 1225} 1226 1227static struct sctp_transport *sctp_trans_elect_tie(struct sctp_transport *trans1, 1228 struct sctp_transport *trans2) 1229{ 1230 if (trans1->error_count > trans2->error_count) { 1231 return trans2; 1232 } else if (trans1->error_count == trans2->error_count && 1233 ktime_after(trans2->last_time_heard, 1234 trans1->last_time_heard)) { 1235 return trans2; 1236 } else { 1237 return trans1; 1238 } 1239} 1240 1241static struct sctp_transport *sctp_trans_elect_best(struct sctp_transport *curr, 1242 struct sctp_transport *best) 1243{ 1244 u8 score_curr, score_best; 1245 1246 if (best == NULL || curr == best) 1247 return curr; 1248 1249 score_curr = sctp_trans_score(curr); 1250 score_best = sctp_trans_score(best); 1251 1252 /* First, try a score-based selection if both transport states 1253 * differ. If we're in a tie, lets try to make a more clever 1254 * decision here based on error counts and last time heard. 1255 */ 1256 if (score_curr > score_best) 1257 return curr; 1258 else if (score_curr == score_best) 1259 return sctp_trans_elect_tie(curr, best); 1260 else 1261 return best; 1262} 1263 1264void sctp_assoc_update_retran_path(struct sctp_association *asoc) 1265{ 1266 struct sctp_transport *trans = asoc->peer.retran_path; 1267 struct sctp_transport *trans_next = NULL; 1268 1269 /* We're done as we only have the one and only path. */ 1270 if (asoc->peer.transport_count == 1) 1271 return; 1272 /* If active_path and retran_path are the same and active, 1273 * then this is the only active path. Use it. 1274 */ 1275 if (asoc->peer.active_path == asoc->peer.retran_path && 1276 asoc->peer.active_path->state == SCTP_ACTIVE) 1277 return; 1278 1279 /* Iterate from retran_path's successor back to retran_path. */ 1280 for (trans = list_next_entry(trans, transports); 1; 1281 trans = list_next_entry(trans, transports)) { 1282 /* Manually skip the head element. */ 1283 if (&trans->transports == &asoc->peer.transport_addr_list) 1284 continue; 1285 if (trans->state == SCTP_UNCONFIRMED) 1286 continue; 1287 trans_next = sctp_trans_elect_best(trans, trans_next); 1288 /* Active is good enough for immediate return. */ 1289 if (trans_next->state == SCTP_ACTIVE) 1290 break; 1291 /* We've reached the end, time to update path. */ 1292 if (trans == asoc->peer.retran_path) 1293 break; 1294 } 1295 1296 asoc->peer.retran_path = trans_next; 1297 1298 pr_debug("%s: association:%p updated new path to addr:%pISpc\n", 1299 __func__, asoc, &asoc->peer.retran_path->ipaddr.sa); 1300} 1301 1302static void sctp_select_active_and_retran_path(struct sctp_association *asoc) 1303{ 1304 struct sctp_transport *trans, *trans_pri = NULL, *trans_sec = NULL; 1305 struct sctp_transport *trans_pf = NULL; 1306 1307 /* Look for the two most recently used active transports. */ 1308 list_for_each_entry(trans, &asoc->peer.transport_addr_list, 1309 transports) { 1310 /* Skip uninteresting transports. */ 1311 if (trans->state == SCTP_INACTIVE || 1312 trans->state == SCTP_UNCONFIRMED) 1313 continue; 1314 /* Keep track of the best PF transport from our 1315 * list in case we don't find an active one. 1316 */ 1317 if (trans->state == SCTP_PF) { 1318 trans_pf = sctp_trans_elect_best(trans, trans_pf); 1319 continue; 1320 } 1321 /* For active transports, pick the most recent ones. */ 1322 if (trans_pri == NULL || 1323 ktime_after(trans->last_time_heard, 1324 trans_pri->last_time_heard)) { 1325 trans_sec = trans_pri; 1326 trans_pri = trans; 1327 } else if (trans_sec == NULL || 1328 ktime_after(trans->last_time_heard, 1329 trans_sec->last_time_heard)) { 1330 trans_sec = trans; 1331 } 1332 } 1333 1334 /* RFC 2960 6.4 Multi-Homed SCTP Endpoints 1335 * 1336 * By default, an endpoint should always transmit to the primary 1337 * path, unless the SCTP user explicitly specifies the 1338 * destination transport address (and possibly source transport 1339 * address) to use. [If the primary is active but not most recent, 1340 * bump the most recently used transport.] 1341 */ 1342 if ((asoc->peer.primary_path->state == SCTP_ACTIVE || 1343 asoc->peer.primary_path->state == SCTP_UNKNOWN) && 1344 asoc->peer.primary_path != trans_pri) { 1345 trans_sec = trans_pri; 1346 trans_pri = asoc->peer.primary_path; 1347 } 1348 1349 /* We did not find anything useful for a possible retransmission 1350 * path; either primary path that we found is the the same as 1351 * the current one, or we didn't generally find an active one. 1352 */ 1353 if (trans_sec == NULL) 1354 trans_sec = trans_pri; 1355 1356 /* If we failed to find a usable transport, just camp on the 1357 * active or pick a PF iff it's the better choice. 1358 */ 1359 if (trans_pri == NULL) { 1360 trans_pri = sctp_trans_elect_best(asoc->peer.active_path, trans_pf); 1361 trans_sec = trans_pri; 1362 } 1363 1364 /* Set the active and retran transports. */ 1365 asoc->peer.active_path = trans_pri; 1366 asoc->peer.retran_path = trans_sec; 1367} 1368 1369struct sctp_transport * 1370sctp_assoc_choose_alter_transport(struct sctp_association *asoc, 1371 struct sctp_transport *last_sent_to) 1372{ 1373 /* If this is the first time packet is sent, use the active path, 1374 * else use the retran path. If the last packet was sent over the 1375 * retran path, update the retran path and use it. 1376 */ 1377 if (last_sent_to == NULL) { 1378 return asoc->peer.active_path; 1379 } else { 1380 if (last_sent_to == asoc->peer.retran_path) 1381 sctp_assoc_update_retran_path(asoc); 1382 1383 return asoc->peer.retran_path; 1384 } 1385} 1386 1387/* Update the association's pmtu and frag_point by going through all the 1388 * transports. This routine is called when a transport's PMTU has changed. 1389 */ 1390void sctp_assoc_sync_pmtu(struct sock *sk, struct sctp_association *asoc) 1391{ 1392 struct sctp_transport *t; 1393 __u32 pmtu = 0; 1394 1395 if (!asoc) 1396 return; 1397 1398 /* Get the lowest pmtu of all the transports. */ 1399 list_for_each_entry(t, &asoc->peer.transport_addr_list, 1400 transports) { 1401 if (t->pmtu_pending && t->dst) { 1402 sctp_transport_update_pmtu(sk, t, dst_mtu(t->dst)); 1403 t->pmtu_pending = 0; 1404 } 1405 if (!pmtu || (t->pathmtu < pmtu)) 1406 pmtu = t->pathmtu; 1407 } 1408 1409 if (pmtu) { 1410 asoc->pathmtu = pmtu; 1411 asoc->frag_point = sctp_frag_point(asoc, pmtu); 1412 } 1413 1414 pr_debug("%s: asoc:%p, pmtu:%d, frag_point:%d\n", __func__, asoc, 1415 asoc->pathmtu, asoc->frag_point); 1416} 1417 1418/* Should we send a SACK to update our peer? */ 1419static inline bool sctp_peer_needs_update(struct sctp_association *asoc) 1420{ 1421 struct net *net = sock_net(asoc->base.sk); 1422 switch (asoc->state) { 1423 case SCTP_STATE_ESTABLISHED: 1424 case SCTP_STATE_SHUTDOWN_PENDING: 1425 case SCTP_STATE_SHUTDOWN_RECEIVED: 1426 case SCTP_STATE_SHUTDOWN_SENT: 1427 if ((asoc->rwnd > asoc->a_rwnd) && 1428 ((asoc->rwnd - asoc->a_rwnd) >= max_t(__u32, 1429 (asoc->base.sk->sk_rcvbuf >> net->sctp.rwnd_upd_shift), 1430 asoc->pathmtu))) 1431 return true; 1432 break; 1433 default: 1434 break; 1435 } 1436 return false; 1437} 1438 1439/* Increase asoc's rwnd by len and send any window update SACK if needed. */ 1440void sctp_assoc_rwnd_increase(struct sctp_association *asoc, unsigned int len) 1441{ 1442 struct sctp_chunk *sack; 1443 struct timer_list *timer; 1444 1445 if (asoc->rwnd_over) { 1446 if (asoc->rwnd_over >= len) { 1447 asoc->rwnd_over -= len; 1448 } else { 1449 asoc->rwnd += (len - asoc->rwnd_over); 1450 asoc->rwnd_over = 0; 1451 } 1452 } else { 1453 asoc->rwnd += len; 1454 } 1455 1456 /* If we had window pressure, start recovering it 1457 * once our rwnd had reached the accumulated pressure 1458 * threshold. The idea is to recover slowly, but up 1459 * to the initial advertised window. 1460 */ 1461 if (asoc->rwnd_press && asoc->rwnd >= asoc->rwnd_press) { 1462 int change = min(asoc->pathmtu, asoc->rwnd_press); 1463 asoc->rwnd += change; 1464 asoc->rwnd_press -= change; 1465 } 1466 1467 pr_debug("%s: asoc:%p rwnd increased by %d to (%u, %u) - %u\n", 1468 __func__, asoc, len, asoc->rwnd, asoc->rwnd_over, 1469 asoc->a_rwnd); 1470 1471 /* Send a window update SACK if the rwnd has increased by at least the 1472 * minimum of the association's PMTU and half of the receive buffer. 1473 * The algorithm used is similar to the one described in 1474 * Section 4.2.3.3 of RFC 1122. 1475 */ 1476 if (sctp_peer_needs_update(asoc)) { 1477 asoc->a_rwnd = asoc->rwnd; 1478 1479 pr_debug("%s: sending window update SACK- asoc:%p rwnd:%u " 1480 "a_rwnd:%u\n", __func__, asoc, asoc->rwnd, 1481 asoc->a_rwnd); 1482 1483 sack = sctp_make_sack(asoc); 1484 if (!sack) 1485 return; 1486 1487 asoc->peer.sack_needed = 0; 1488 1489 sctp_outq_tail(&asoc->outqueue, sack); 1490 1491 /* Stop the SACK timer. */ 1492 timer = &asoc->timers[SCTP_EVENT_TIMEOUT_SACK]; 1493 if (del_timer(timer)) 1494 sctp_association_put(asoc); 1495 } 1496} 1497 1498/* Decrease asoc's rwnd by len. */ 1499void sctp_assoc_rwnd_decrease(struct sctp_association *asoc, unsigned int len) 1500{ 1501 int rx_count; 1502 int over = 0; 1503 1504 if (unlikely(!asoc->rwnd || asoc->rwnd_over)) 1505 pr_debug("%s: association:%p has asoc->rwnd:%u, " 1506 "asoc->rwnd_over:%u!\n", __func__, asoc, 1507 asoc->rwnd, asoc->rwnd_over); 1508 1509 if (asoc->ep->rcvbuf_policy) 1510 rx_count = atomic_read(&asoc->rmem_alloc); 1511 else 1512 rx_count = atomic_read(&asoc->base.sk->sk_rmem_alloc); 1513 1514 /* If we've reached or overflowed our receive buffer, announce 1515 * a 0 rwnd if rwnd would still be positive. Store the 1516 * the potential pressure overflow so that the window can be restored 1517 * back to original value. 1518 */ 1519 if (rx_count >= asoc->base.sk->sk_rcvbuf) 1520 over = 1; 1521 1522 if (asoc->rwnd >= len) { 1523 asoc->rwnd -= len; 1524 if (over) { 1525 asoc->rwnd_press += asoc->rwnd; 1526 asoc->rwnd = 0; 1527 } 1528 } else { 1529 asoc->rwnd_over = len - asoc->rwnd; 1530 asoc->rwnd = 0; 1531 } 1532 1533 pr_debug("%s: asoc:%p rwnd decreased by %d to (%u, %u, %u)\n", 1534 __func__, asoc, len, asoc->rwnd, asoc->rwnd_over, 1535 asoc->rwnd_press); 1536} 1537 1538/* Build the bind address list for the association based on info from the 1539 * local endpoint and the remote peer. 1540 */ 1541int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc, 1542 sctp_scope_t scope, gfp_t gfp) 1543{ 1544 int flags; 1545 1546 /* Use scoping rules to determine the subset of addresses from 1547 * the endpoint. 1548 */ 1549 flags = (PF_INET6 == asoc->base.sk->sk_family) ? SCTP_ADDR6_ALLOWED : 0; 1550 if (asoc->peer.ipv4_address) 1551 flags |= SCTP_ADDR4_PEERSUPP; 1552 if (asoc->peer.ipv6_address) 1553 flags |= SCTP_ADDR6_PEERSUPP; 1554 1555 return sctp_bind_addr_copy(sock_net(asoc->base.sk), 1556 &asoc->base.bind_addr, 1557 &asoc->ep->base.bind_addr, 1558 scope, gfp, flags); 1559} 1560 1561/* Build the association's bind address list from the cookie. */ 1562int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *asoc, 1563 struct sctp_cookie *cookie, 1564 gfp_t gfp) 1565{ 1566 int var_size2 = ntohs(cookie->peer_init->chunk_hdr.length); 1567 int var_size3 = cookie->raw_addr_list_len; 1568 __u8 *raw = (__u8 *)cookie->peer_init + var_size2; 1569 1570 return sctp_raw_to_bind_addrs(&asoc->base.bind_addr, raw, var_size3, 1571 asoc->ep->base.bind_addr.port, gfp); 1572} 1573 1574/* Lookup laddr in the bind address list of an association. */ 1575int sctp_assoc_lookup_laddr(struct sctp_association *asoc, 1576 const union sctp_addr *laddr) 1577{ 1578 int found = 0; 1579 1580 if ((asoc->base.bind_addr.port == ntohs(laddr->v4.sin_port)) && 1581 sctp_bind_addr_match(&asoc->base.bind_addr, laddr, 1582 sctp_sk(asoc->base.sk))) 1583 found = 1; 1584 1585 return found; 1586} 1587 1588/* Set an association id for a given association */ 1589int sctp_assoc_set_id(struct sctp_association *asoc, gfp_t gfp) 1590{ 1591 bool preload = !!(gfp & __GFP_WAIT); 1592 int ret; 1593 1594 /* If the id is already assigned, keep it. */ 1595 if (asoc->assoc_id) 1596 return 0; 1597 1598 if (preload) 1599 idr_preload(gfp); 1600 spin_lock_bh(&sctp_assocs_id_lock); 1601 /* 0 is not a valid assoc_id, must be >= 1 */ 1602 ret = idr_alloc_cyclic(&sctp_assocs_id, asoc, 1, 0, GFP_NOWAIT); 1603 spin_unlock_bh(&sctp_assocs_id_lock); 1604 if (preload) 1605 idr_preload_end(); 1606 if (ret < 0) 1607 return ret; 1608 1609 asoc->assoc_id = (sctp_assoc_t)ret; 1610 return 0; 1611} 1612 1613/* Free the ASCONF queue */ 1614static void sctp_assoc_free_asconf_queue(struct sctp_association *asoc) 1615{ 1616 struct sctp_chunk *asconf; 1617 struct sctp_chunk *tmp; 1618 1619 list_for_each_entry_safe(asconf, tmp, &asoc->addip_chunk_list, list) { 1620 list_del_init(&asconf->list); 1621 sctp_chunk_free(asconf); 1622 } 1623} 1624 1625/* Free asconf_ack cache */ 1626static void sctp_assoc_free_asconf_acks(struct sctp_association *asoc) 1627{ 1628 struct sctp_chunk *ack; 1629 struct sctp_chunk *tmp; 1630 1631 list_for_each_entry_safe(ack, tmp, &asoc->asconf_ack_list, 1632 transmitted_list) { 1633 list_del_init(&ack->transmitted_list); 1634 sctp_chunk_free(ack); 1635 } 1636} 1637 1638/* Clean up the ASCONF_ACK queue */ 1639void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc) 1640{ 1641 struct sctp_chunk *ack; 1642 struct sctp_chunk *tmp; 1643 1644 /* We can remove all the entries from the queue up to 1645 * the "Peer-Sequence-Number". 1646 */ 1647 list_for_each_entry_safe(ack, tmp, &asoc->asconf_ack_list, 1648 transmitted_list) { 1649 if (ack->subh.addip_hdr->serial == 1650 htonl(asoc->peer.addip_serial)) 1651 break; 1652 1653 list_del_init(&ack->transmitted_list); 1654 sctp_chunk_free(ack); 1655 } 1656} 1657 1658/* Find the ASCONF_ACK whose serial number matches ASCONF */ 1659struct sctp_chunk *sctp_assoc_lookup_asconf_ack( 1660 const struct sctp_association *asoc, 1661 __be32 serial) 1662{ 1663 struct sctp_chunk *ack; 1664 1665 /* Walk through the list of cached ASCONF-ACKs and find the 1666 * ack chunk whose serial number matches that of the request. 1667 */ 1668 list_for_each_entry(ack, &asoc->asconf_ack_list, transmitted_list) { 1669 if (sctp_chunk_pending(ack)) 1670 continue; 1671 if (ack->subh.addip_hdr->serial == serial) { 1672 sctp_chunk_hold(ack); 1673 return ack; 1674 } 1675 } 1676 1677 return NULL; 1678} 1679 1680void sctp_asconf_queue_teardown(struct sctp_association *asoc) 1681{ 1682 /* Free any cached ASCONF_ACK chunk. */ 1683 sctp_assoc_free_asconf_acks(asoc); 1684 1685 /* Free the ASCONF queue. */ 1686 sctp_assoc_free_asconf_queue(asoc); 1687 1688 /* Free any cached ASCONF chunk. */ 1689 if (asoc->addip_last_asconf) 1690 sctp_chunk_free(asoc->addip_last_asconf); 1691} 1692