1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* SCTP kernel implementation 3 * (C) Copyright IBM Corp. 2001, 2004 4 * Copyright (c) 1999-2000 Cisco, Inc. 5 * Copyright (c) 1999-2001 Motorola, Inc. 6 * Copyright (c) 2001 Intel Corp. 7 * Copyright (c) 2001 La Monte H.P. Yarroll 8 * 9 * This file is part of the SCTP kernel implementation 10 * 11 * This module provides the abstraction for an SCTP association. 12 * 13 * Please send any bug reports or fixes you make to the 14 * email address(es): 15 * lksctp developers <linux-sctp@vger.kernel.org> 16 * 17 * Written or modified by: 18 * La Monte H.P. Yarroll <piggy@acm.org> 19 * Karl Knutson <karl@athena.chicago.il.us> 20 * Jon Grimm <jgrimm@us.ibm.com> 21 * Xingang Guo <xingang.guo@intel.com> 22 * Hui Huang <hui.huang@nokia.com> 23 * Sridhar Samudrala <sri@us.ibm.com> 24 * Daisy Chang <daisyc@us.ibm.com> 25 * Ryan Layer <rmlayer@us.ibm.com> 26 * Kevin Gao <kevin.gao@intel.com> 27 */ 28 29 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 30 31 #include <linux/types.h> 32 #include <linux/fcntl.h> 33 #include <linux/poll.h> 34 #include <linux/init.h> 35 36 #include <linux/slab.h> 37 #include <linux/in.h> 38 #include <net/ipv6.h> 39 #include <net/sctp/sctp.h> 40 #include <net/sctp/sm.h> 41 42 /* Forward declarations for internal functions. */ 43 static void sctp_select_active_and_retran_path(struct sctp_association *asoc); 44 static void sctp_assoc_bh_rcv(struct work_struct *work); 45 static void sctp_assoc_free_asconf_acks(struct sctp_association *asoc); 46 static void sctp_assoc_free_asconf_queue(struct sctp_association *asoc); 47 48 /* 1st Level Abstractions. */ 49 50 /* Initialize a new association from provided memory. */ 51 static struct sctp_association *sctp_association_init( 52 struct sctp_association *asoc, 53 const struct sctp_endpoint *ep, 54 const struct sock *sk, 55 enum sctp_scope scope, gfp_t gfp) 56 { 57 struct sctp_sock *sp; 58 struct sctp_paramhdr *p; 59 int i; 60 61 /* Retrieve the SCTP per socket area. */ 62 sp = sctp_sk((struct sock *)sk); 63 64 /* Discarding const is appropriate here. */ 65 asoc->ep = (struct sctp_endpoint *)ep; 66 asoc->base.sk = (struct sock *)sk; 67 asoc->base.net = sock_net(sk); 68 69 sctp_endpoint_hold(asoc->ep); 70 sock_hold(asoc->base.sk); 71 72 /* Initialize the common base substructure. */ 73 asoc->base.type = SCTP_EP_TYPE_ASSOCIATION; 74 75 /* Initialize the object handling fields. */ 76 refcount_set(&asoc->base.refcnt, 1); 77 78 /* Initialize the bind addr area. */ 79 sctp_bind_addr_init(&asoc->base.bind_addr, ep->base.bind_addr.port); 80 81 asoc->state = SCTP_STATE_CLOSED; 82 asoc->cookie_life = ms_to_ktime(sp->assocparams.sasoc_cookie_life); 83 asoc->user_frag = sp->user_frag; 84 85 /* Set the association max_retrans and RTO values from the 86 * socket values. 87 */ 88 asoc->max_retrans = sp->assocparams.sasoc_asocmaxrxt; 89 asoc->pf_retrans = sp->pf_retrans; 90 asoc->ps_retrans = sp->ps_retrans; 91 asoc->pf_expose = sp->pf_expose; 92 93 asoc->rto_initial = msecs_to_jiffies(sp->rtoinfo.srto_initial); 94 asoc->rto_max = msecs_to_jiffies(sp->rtoinfo.srto_max); 95 asoc->rto_min = msecs_to_jiffies(sp->rtoinfo.srto_min); 96 97 /* Initialize the association's heartbeat interval based on the 98 * sock configured value. 99 */ 100 asoc->hbinterval = msecs_to_jiffies(sp->hbinterval); 101 asoc->probe_interval = msecs_to_jiffies(sp->probe_interval); 102 103 asoc->encap_port = sp->encap_port; 104 105 /* Initialize path max retrans value. */ 106 asoc->pathmaxrxt = sp->pathmaxrxt; 107 108 asoc->flowlabel = sp->flowlabel; 109 asoc->dscp = sp->dscp; 110 111 /* Set association default SACK delay */ 112 asoc->sackdelay = msecs_to_jiffies(sp->sackdelay); 113 asoc->sackfreq = sp->sackfreq; 114 115 /* Set the association default flags controlling 116 * Heartbeat, SACK delay, and Path MTU Discovery. 117 */ 118 asoc->param_flags = sp->param_flags; 119 120 /* Initialize the maximum number of new data packets that can be sent 121 * in a burst. 122 */ 123 asoc->max_burst = sp->max_burst; 124 125 asoc->subscribe = sp->subscribe; 126 127 /* initialize association timers */ 128 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] = asoc->rto_initial; 129 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] = asoc->rto_initial; 130 asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = asoc->rto_initial; 131 132 /* sctpimpguide Section 2.12.2 133 * If the 'T5-shutdown-guard' timer is used, it SHOULD be set to the 134 * recommended value of 5 times 'RTO.Max'. 135 */ 136 asoc->timeouts[SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD] 137 = 5 * asoc->rto_max; 138 139 asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] = asoc->sackdelay; 140 asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE] = sp->autoclose * HZ; 141 142 /* Initializes the timers */ 143 for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i) 144 timer_setup(&asoc->timers[i], sctp_timer_events[i], 0); 145 146 /* Pull default initialization values from the sock options. 147 * Note: This assumes that the values have already been 148 * validated in the sock. 149 */ 150 asoc->c.sinit_max_instreams = sp->initmsg.sinit_max_instreams; 151 asoc->c.sinit_num_ostreams = sp->initmsg.sinit_num_ostreams; 152 asoc->max_init_attempts = sp->initmsg.sinit_max_attempts; 153 154 asoc->max_init_timeo = 155 msecs_to_jiffies(sp->initmsg.sinit_max_init_timeo); 156 157 /* Set the local window size for receive. 158 * This is also the rcvbuf space per association. 159 * RFC 6 - A SCTP receiver MUST be able to receive a minimum of 160 * 1500 bytes in one SCTP packet. 161 */ 162 if ((sk->sk_rcvbuf/2) < SCTP_DEFAULT_MINWINDOW) 163 asoc->rwnd = SCTP_DEFAULT_MINWINDOW; 164 else 165 asoc->rwnd = sk->sk_rcvbuf/2; 166 167 asoc->a_rwnd = asoc->rwnd; 168 169 /* Use my own max window until I learn something better. */ 170 asoc->peer.rwnd = SCTP_DEFAULT_MAXWINDOW; 171 172 /* Initialize the receive memory counter */ 173 atomic_set(&asoc->rmem_alloc, 0); 174 175 init_waitqueue_head(&asoc->wait); 176 177 asoc->c.my_vtag = sctp_generate_tag(ep); 178 asoc->c.my_port = ep->base.bind_addr.port; 179 180 asoc->c.initial_tsn = sctp_generate_tsn(ep); 181 182 asoc->next_tsn = asoc->c.initial_tsn; 183 184 asoc->ctsn_ack_point = asoc->next_tsn - 1; 185 asoc->adv_peer_ack_point = asoc->ctsn_ack_point; 186 asoc->highest_sacked = asoc->ctsn_ack_point; 187 asoc->last_cwr_tsn = asoc->ctsn_ack_point; 188 189 /* ADDIP Section 4.1 Asconf Chunk Procedures 190 * 191 * When an endpoint has an ASCONF signaled change to be sent to the 192 * remote endpoint it should do the following: 193 * ... 194 * A2) a serial number should be assigned to the chunk. The serial 195 * number SHOULD be a monotonically increasing number. The serial 196 * numbers SHOULD be initialized at the start of the 197 * association to the same value as the initial TSN. 198 */ 199 asoc->addip_serial = asoc->c.initial_tsn; 200 asoc->strreset_outseq = asoc->c.initial_tsn; 201 202 INIT_LIST_HEAD(&asoc->addip_chunk_list); 203 INIT_LIST_HEAD(&asoc->asconf_ack_list); 204 205 /* Make an empty list of remote transport addresses. */ 206 INIT_LIST_HEAD(&asoc->peer.transport_addr_list); 207 208 /* RFC 2960 5.1 Normal Establishment of an Association 209 * 210 * After the reception of the first data chunk in an 211 * association the endpoint must immediately respond with a 212 * sack to acknowledge the data chunk. Subsequent 213 * acknowledgements should be done as described in Section 214 * 6.2. 215 * 216 * [We implement this by telling a new association that it 217 * already received one packet.] 218 */ 219 asoc->peer.sack_needed = 1; 220 asoc->peer.sack_generation = 1; 221 222 /* Create an input queue. */ 223 sctp_inq_init(&asoc->base.inqueue); 224 sctp_inq_set_th_handler(&asoc->base.inqueue, sctp_assoc_bh_rcv); 225 226 /* Create an output queue. */ 227 sctp_outq_init(asoc, &asoc->outqueue); 228 229 if (!sctp_ulpq_init(&asoc->ulpq, asoc)) 230 goto fail_init; 231 232 if (sctp_stream_init(&asoc->stream, asoc->c.sinit_num_ostreams, 233 0, gfp)) 234 goto fail_init; 235 236 /* Initialize default path MTU. */ 237 asoc->pathmtu = sp->pathmtu; 238 sctp_assoc_update_frag_point(asoc); 239 240 /* Assume that peer would support both address types unless we are 241 * told otherwise. 242 */ 243 asoc->peer.ipv4_address = 1; 244 if (asoc->base.sk->sk_family == PF_INET6) 245 asoc->peer.ipv6_address = 1; 246 INIT_LIST_HEAD(&asoc->asocs); 247 248 asoc->default_stream = sp->default_stream; 249 asoc->default_ppid = sp->default_ppid; 250 asoc->default_flags = sp->default_flags; 251 asoc->default_context = sp->default_context; 252 asoc->default_timetolive = sp->default_timetolive; 253 asoc->default_rcv_context = sp->default_rcv_context; 254 255 /* AUTH related initializations */ 256 INIT_LIST_HEAD(&asoc->endpoint_shared_keys); 257 if (sctp_auth_asoc_copy_shkeys(ep, asoc, gfp)) 258 goto stream_free; 259 260 asoc->active_key_id = ep->active_key_id; 261 asoc->strreset_enable = ep->strreset_enable; 262 263 /* Save the hmacs and chunks list into this association */ 264 if (ep->auth_hmacs_list) 265 memcpy(asoc->c.auth_hmacs, ep->auth_hmacs_list, 266 ntohs(ep->auth_hmacs_list->param_hdr.length)); 267 if (ep->auth_chunk_list) 268 memcpy(asoc->c.auth_chunks, ep->auth_chunk_list, 269 ntohs(ep->auth_chunk_list->param_hdr.length)); 270 271 /* Get the AUTH random number for this association */ 272 p = (struct sctp_paramhdr *)asoc->c.auth_random; 273 p->type = SCTP_PARAM_RANDOM; 274 p->length = htons(sizeof(*p) + SCTP_AUTH_RANDOM_LENGTH); 275 get_random_bytes(p+1, SCTP_AUTH_RANDOM_LENGTH); 276 277 return asoc; 278 279 stream_free: 280 sctp_stream_free(&asoc->stream); 281 fail_init: 282 sock_put(asoc->base.sk); 283 sctp_endpoint_put(asoc->ep); 284 return NULL; 285 } 286 287 /* Allocate and initialize a new association */ 288 struct sctp_association *sctp_association_new(const struct sctp_endpoint *ep, 289 const struct sock *sk, 290 enum sctp_scope scope, gfp_t gfp) 291 { 292 struct sctp_association *asoc; 293 294 asoc = kzalloc(sizeof(*asoc), gfp); 295 if (!asoc) 296 goto fail; 297 298 if (!sctp_association_init(asoc, ep, sk, scope, gfp)) 299 goto fail_init; 300 301 SCTP_DBG_OBJCNT_INC(assoc); 302 303 pr_debug("Created asoc %p\n", asoc); 304 305 return asoc; 306 307 fail_init: 308 kfree(asoc); 309 fail: 310 return NULL; 311 } 312 313 /* Free this association if possible. There may still be users, so 314 * the actual deallocation may be delayed. 315 */ 316 void sctp_association_free(struct sctp_association *asoc) 317 { 318 struct sock *sk = asoc->base.sk; 319 struct sctp_transport *transport; 320 struct list_head *pos, *temp; 321 int i; 322 323 /* Only real associations count against the endpoint, so 324 * don't bother for if this is a temporary association. 325 */ 326 if (!list_empty(&asoc->asocs)) { 327 list_del(&asoc->asocs); 328 329 /* Decrement the backlog value for a TCP-style listening 330 * socket. 331 */ 332 if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING)) 333 sk_acceptq_removed(sk); 334 } 335 336 /* Mark as dead, so other users can know this structure is 337 * going away. 338 */ 339 asoc->base.dead = true; 340 341 /* Dispose of any data lying around in the outqueue. */ 342 sctp_outq_free(&asoc->outqueue); 343 344 /* Dispose of any pending messages for the upper layer. */ 345 sctp_ulpq_free(&asoc->ulpq); 346 347 /* Dispose of any pending chunks on the inqueue. */ 348 sctp_inq_free(&asoc->base.inqueue); 349 350 sctp_tsnmap_free(&asoc->peer.tsn_map); 351 352 /* Free stream information. */ 353 sctp_stream_free(&asoc->stream); 354 355 if (asoc->strreset_chunk) 356 sctp_chunk_free(asoc->strreset_chunk); 357 358 /* Clean up the bound address list. */ 359 sctp_bind_addr_free(&asoc->base.bind_addr); 360 361 /* Do we need to go through all of our timers and 362 * delete them? To be safe we will try to delete all, but we 363 * should be able to go through and make a guess based 364 * on our state. 365 */ 366 for (i = SCTP_EVENT_TIMEOUT_NONE; i < SCTP_NUM_TIMEOUT_TYPES; ++i) { 367 if (del_timer(&asoc->timers[i])) 368 sctp_association_put(asoc); 369 } 370 371 /* Free peer's cached cookie. */ 372 kfree(asoc->peer.cookie); 373 kfree(asoc->peer.peer_random); 374 kfree(asoc->peer.peer_chunks); 375 kfree(asoc->peer.peer_hmacs); 376 377 /* Release the transport structures. */ 378 list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) { 379 transport = list_entry(pos, struct sctp_transport, transports); 380 list_del_rcu(pos); 381 sctp_unhash_transport(transport); 382 sctp_transport_free(transport); 383 } 384 385 asoc->peer.transport_count = 0; 386 387 sctp_asconf_queue_teardown(asoc); 388 389 /* Free pending address space being deleted */ 390 kfree(asoc->asconf_addr_del_pending); 391 392 /* AUTH - Free the endpoint shared keys */ 393 sctp_auth_destroy_keys(&asoc->endpoint_shared_keys); 394 395 /* AUTH - Free the association shared key */ 396 sctp_auth_key_put(asoc->asoc_shared_key); 397 398 sctp_association_put(asoc); 399 } 400 401 /* Cleanup and free up an association. */ 402 static void sctp_association_destroy(struct sctp_association *asoc) 403 { 404 if (unlikely(!asoc->base.dead)) { 405 WARN(1, "Attempt to destroy undead association %p!\n", asoc); 406 return; 407 } 408 409 sctp_endpoint_put(asoc->ep); 410 sock_put(asoc->base.sk); 411 412 if (asoc->assoc_id != 0) { 413 spin_lock_bh(&sctp_assocs_id_lock); 414 idr_remove(&sctp_assocs_id, asoc->assoc_id); 415 spin_unlock_bh(&sctp_assocs_id_lock); 416 } 417 418 WARN_ON(atomic_read(&asoc->rmem_alloc)); 419 420 kfree_rcu(asoc, rcu); 421 SCTP_DBG_OBJCNT_DEC(assoc); 422 } 423 424 /* Change the primary destination address for the peer. */ 425 void sctp_assoc_set_primary(struct sctp_association *asoc, 426 struct sctp_transport *transport) 427 { 428 int changeover = 0; 429 430 /* it's a changeover only if we already have a primary path 431 * that we are changing 432 */ 433 if (asoc->peer.primary_path != NULL && 434 asoc->peer.primary_path != transport) 435 changeover = 1 ; 436 437 asoc->peer.primary_path = transport; 438 sctp_ulpevent_notify_peer_addr_change(transport, 439 SCTP_ADDR_MADE_PRIM, 0); 440 441 /* Set a default msg_name for events. */ 442 memcpy(&asoc->peer.primary_addr, &transport->ipaddr, 443 sizeof(union sctp_addr)); 444 445 /* If the primary path is changing, assume that the 446 * user wants to use this new path. 447 */ 448 if ((transport->state == SCTP_ACTIVE) || 449 (transport->state == SCTP_UNKNOWN)) 450 asoc->peer.active_path = transport; 451 452 /* 453 * SFR-CACC algorithm: 454 * Upon the receipt of a request to change the primary 455 * destination address, on the data structure for the new 456 * primary destination, the sender MUST do the following: 457 * 458 * 1) If CHANGEOVER_ACTIVE is set, then there was a switch 459 * to this destination address earlier. The sender MUST set 460 * CYCLING_CHANGEOVER to indicate that this switch is a 461 * double switch to the same destination address. 462 * 463 * Really, only bother is we have data queued or outstanding on 464 * the association. 465 */ 466 if (!asoc->outqueue.outstanding_bytes && !asoc->outqueue.out_qlen) 467 return; 468 469 if (transport->cacc.changeover_active) 470 transport->cacc.cycling_changeover = changeover; 471 472 /* 2) The sender MUST set CHANGEOVER_ACTIVE to indicate that 473 * a changeover has occurred. 474 */ 475 transport->cacc.changeover_active = changeover; 476 477 /* 3) The sender MUST store the next TSN to be sent in 478 * next_tsn_at_change. 479 */ 480 transport->cacc.next_tsn_at_change = asoc->next_tsn; 481 } 482 483 /* Remove a transport from an association. */ 484 void sctp_assoc_rm_peer(struct sctp_association *asoc, 485 struct sctp_transport *peer) 486 { 487 struct sctp_transport *transport; 488 struct list_head *pos; 489 struct sctp_chunk *ch; 490 491 pr_debug("%s: association:%p addr:%pISpc\n", 492 __func__, asoc, &peer->ipaddr.sa); 493 494 /* If we are to remove the current retran_path, update it 495 * to the next peer before removing this peer from the list. 496 */ 497 if (asoc->peer.retran_path == peer) 498 sctp_assoc_update_retran_path(asoc); 499 500 /* Remove this peer from the list. */ 501 list_del_rcu(&peer->transports); 502 /* Remove this peer from the transport hashtable */ 503 sctp_unhash_transport(peer); 504 505 /* Get the first transport of asoc. */ 506 pos = asoc->peer.transport_addr_list.next; 507 transport = list_entry(pos, struct sctp_transport, transports); 508 509 /* Update any entries that match the peer to be deleted. */ 510 if (asoc->peer.primary_path == peer) 511 sctp_assoc_set_primary(asoc, transport); 512 if (asoc->peer.active_path == peer) 513 asoc->peer.active_path = transport; 514 if (asoc->peer.retran_path == peer) 515 asoc->peer.retran_path = transport; 516 if (asoc->peer.last_data_from == peer) 517 asoc->peer.last_data_from = transport; 518 519 if (asoc->strreset_chunk && 520 asoc->strreset_chunk->transport == peer) { 521 asoc->strreset_chunk->transport = transport; 522 sctp_transport_reset_reconf_timer(transport); 523 } 524 525 /* If we remove the transport an INIT was last sent to, set it to 526 * NULL. Combined with the update of the retran path above, this 527 * will cause the next INIT to be sent to the next available 528 * transport, maintaining the cycle. 529 */ 530 if (asoc->init_last_sent_to == peer) 531 asoc->init_last_sent_to = NULL; 532 533 /* If we remove the transport an SHUTDOWN was last sent to, set it 534 * to NULL. Combined with the update of the retran path above, this 535 * will cause the next SHUTDOWN to be sent to the next available 536 * transport, maintaining the cycle. 537 */ 538 if (asoc->shutdown_last_sent_to == peer) 539 asoc->shutdown_last_sent_to = NULL; 540 541 /* If we remove the transport an ASCONF was last sent to, set it to 542 * NULL. 543 */ 544 if (asoc->addip_last_asconf && 545 asoc->addip_last_asconf->transport == peer) 546 asoc->addip_last_asconf->transport = NULL; 547 548 /* If we have something on the transmitted list, we have to 549 * save it off. The best place is the active path. 550 */ 551 if (!list_empty(&peer->transmitted)) { 552 struct sctp_transport *active = asoc->peer.active_path; 553 554 /* Reset the transport of each chunk on this list */ 555 list_for_each_entry(ch, &peer->transmitted, 556 transmitted_list) { 557 ch->transport = NULL; 558 ch->rtt_in_progress = 0; 559 } 560 561 list_splice_tail_init(&peer->transmitted, 562 &active->transmitted); 563 564 /* Start a T3 timer here in case it wasn't running so 565 * that these migrated packets have a chance to get 566 * retransmitted. 567 */ 568 if (!timer_pending(&active->T3_rtx_timer)) 569 if (!mod_timer(&active->T3_rtx_timer, 570 jiffies + active->rto)) 571 sctp_transport_hold(active); 572 } 573 574 list_for_each_entry(ch, &asoc->outqueue.out_chunk_list, list) 575 if (ch->transport == peer) 576 ch->transport = NULL; 577 578 asoc->peer.transport_count--; 579 580 sctp_ulpevent_notify_peer_addr_change(peer, SCTP_ADDR_REMOVED, 0); 581 sctp_transport_free(peer); 582 } 583 584 /* Add a transport address to an association. */ 585 struct sctp_transport *sctp_assoc_add_peer(struct sctp_association *asoc, 586 const union sctp_addr *addr, 587 const gfp_t gfp, 588 const int peer_state) 589 { 590 struct sctp_transport *peer; 591 struct sctp_sock *sp; 592 unsigned short port; 593 594 sp = sctp_sk(asoc->base.sk); 595 596 /* AF_INET and AF_INET6 share common port field. */ 597 port = ntohs(addr->v4.sin_port); 598 599 pr_debug("%s: association:%p addr:%pISpc state:%d\n", __func__, 600 asoc, &addr->sa, peer_state); 601 602 /* Set the port if it has not been set yet. */ 603 if (0 == asoc->peer.port) 604 asoc->peer.port = port; 605 606 /* Check to see if this is a duplicate. */ 607 peer = sctp_assoc_lookup_paddr(asoc, addr); 608 if (peer) { 609 /* An UNKNOWN state is only set on transports added by 610 * user in sctp_connectx() call. Such transports should be 611 * considered CONFIRMED per RFC 4960, Section 5.4. 612 */ 613 if (peer->state == SCTP_UNKNOWN) { 614 peer->state = SCTP_ACTIVE; 615 } 616 return peer; 617 } 618 619 peer = sctp_transport_new(asoc->base.net, addr, gfp); 620 if (!peer) 621 return NULL; 622 623 sctp_transport_set_owner(peer, asoc); 624 625 /* Initialize the peer's heartbeat interval based on the 626 * association configured value. 627 */ 628 peer->hbinterval = asoc->hbinterval; 629 peer->probe_interval = asoc->probe_interval; 630 631 peer->encap_port = asoc->encap_port; 632 633 /* Set the path max_retrans. */ 634 peer->pathmaxrxt = asoc->pathmaxrxt; 635 636 /* And the partial failure retrans threshold */ 637 peer->pf_retrans = asoc->pf_retrans; 638 /* And the primary path switchover retrans threshold */ 639 peer->ps_retrans = asoc->ps_retrans; 640 641 /* Initialize the peer's SACK delay timeout based on the 642 * association configured value. 643 */ 644 peer->sackdelay = asoc->sackdelay; 645 peer->sackfreq = asoc->sackfreq; 646 647 if (addr->sa.sa_family == AF_INET6) { 648 __be32 info = addr->v6.sin6_flowinfo; 649 650 if (info) { 651 peer->flowlabel = ntohl(info & IPV6_FLOWLABEL_MASK); 652 peer->flowlabel |= SCTP_FLOWLABEL_SET_MASK; 653 } else { 654 peer->flowlabel = asoc->flowlabel; 655 } 656 } 657 peer->dscp = asoc->dscp; 658 659 /* Enable/disable heartbeat, SACK delay, and path MTU discovery 660 * based on association setting. 661 */ 662 peer->param_flags = asoc->param_flags; 663 664 /* Initialize the pmtu of the transport. */ 665 sctp_transport_route(peer, NULL, sp); 666 667 /* If this is the first transport addr on this association, 668 * initialize the association PMTU to the peer's PMTU. 669 * If not and the current association PMTU is higher than the new 670 * peer's PMTU, reset the association PMTU to the new peer's PMTU. 671 */ 672 sctp_assoc_set_pmtu(asoc, asoc->pathmtu ? 673 min_t(int, peer->pathmtu, asoc->pathmtu) : 674 peer->pathmtu); 675 676 peer->pmtu_pending = 0; 677 678 /* The asoc->peer.port might not be meaningful yet, but 679 * initialize the packet structure anyway. 680 */ 681 sctp_packet_init(&peer->packet, peer, asoc->base.bind_addr.port, 682 asoc->peer.port); 683 684 /* 7.2.1 Slow-Start 685 * 686 * o The initial cwnd before DATA transmission or after a sufficiently 687 * long idle period MUST be set to 688 * min(4*MTU, max(2*MTU, 4380 bytes)) 689 * 690 * o The initial value of ssthresh MAY be arbitrarily high 691 * (for example, implementations MAY use the size of the 692 * receiver advertised window). 693 */ 694 peer->cwnd = min(4*asoc->pathmtu, max_t(__u32, 2*asoc->pathmtu, 4380)); 695 696 /* At this point, we may not have the receiver's advertised window, 697 * so initialize ssthresh to the default value and it will be set 698 * later when we process the INIT. 699 */ 700 peer->ssthresh = SCTP_DEFAULT_MAXWINDOW; 701 702 peer->partial_bytes_acked = 0; 703 peer->flight_size = 0; 704 peer->burst_limited = 0; 705 706 /* Set the transport's RTO.initial value */ 707 peer->rto = asoc->rto_initial; 708 sctp_max_rto(asoc, peer); 709 710 /* Set the peer's active state. */ 711 peer->state = peer_state; 712 713 /* Add this peer into the transport hashtable */ 714 if (sctp_hash_transport(peer)) { 715 sctp_transport_free(peer); 716 return NULL; 717 } 718 719 sctp_transport_pl_reset(peer); 720 721 /* Attach the remote transport to our asoc. */ 722 list_add_tail_rcu(&peer->transports, &asoc->peer.transport_addr_list); 723 asoc->peer.transport_count++; 724 725 sctp_ulpevent_notify_peer_addr_change(peer, SCTP_ADDR_ADDED, 0); 726 727 /* If we do not yet have a primary path, set one. */ 728 if (!asoc->peer.primary_path) { 729 sctp_assoc_set_primary(asoc, peer); 730 asoc->peer.retran_path = peer; 731 } 732 733 if (asoc->peer.active_path == asoc->peer.retran_path && 734 peer->state != SCTP_UNCONFIRMED) { 735 asoc->peer.retran_path = peer; 736 } 737 738 return peer; 739 } 740 741 /* Delete a transport address from an association. */ 742 void sctp_assoc_del_peer(struct sctp_association *asoc, 743 const union sctp_addr *addr) 744 { 745 struct list_head *pos; 746 struct list_head *temp; 747 struct sctp_transport *transport; 748 749 list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) { 750 transport = list_entry(pos, struct sctp_transport, transports); 751 if (sctp_cmp_addr_exact(addr, &transport->ipaddr)) { 752 /* Do book keeping for removing the peer and free it. */ 753 sctp_assoc_rm_peer(asoc, transport); 754 break; 755 } 756 } 757 } 758 759 /* Lookup a transport by address. */ 760 struct sctp_transport *sctp_assoc_lookup_paddr( 761 const struct sctp_association *asoc, 762 const union sctp_addr *address) 763 { 764 struct sctp_transport *t; 765 766 /* Cycle through all transports searching for a peer address. */ 767 768 list_for_each_entry(t, &asoc->peer.transport_addr_list, 769 transports) { 770 if (sctp_cmp_addr_exact(address, &t->ipaddr)) 771 return t; 772 } 773 774 return NULL; 775 } 776 777 /* Remove all transports except a give one */ 778 void sctp_assoc_del_nonprimary_peers(struct sctp_association *asoc, 779 struct sctp_transport *primary) 780 { 781 struct sctp_transport *temp; 782 struct sctp_transport *t; 783 784 list_for_each_entry_safe(t, temp, &asoc->peer.transport_addr_list, 785 transports) { 786 /* if the current transport is not the primary one, delete it */ 787 if (t != primary) 788 sctp_assoc_rm_peer(asoc, t); 789 } 790 } 791 792 /* Engage in transport control operations. 793 * Mark the transport up or down and send a notification to the user. 794 * Select and update the new active and retran paths. 795 */ 796 void sctp_assoc_control_transport(struct sctp_association *asoc, 797 struct sctp_transport *transport, 798 enum sctp_transport_cmd command, 799 sctp_sn_error_t error) 800 { 801 int spc_state = SCTP_ADDR_AVAILABLE; 802 bool ulp_notify = true; 803 804 /* Record the transition on the transport. */ 805 switch (command) { 806 case SCTP_TRANSPORT_UP: 807 /* If we are moving from UNCONFIRMED state due 808 * to heartbeat success, report the SCTP_ADDR_CONFIRMED 809 * state to the user, otherwise report SCTP_ADDR_AVAILABLE. 810 */ 811 if (transport->state == SCTP_PF && 812 asoc->pf_expose != SCTP_PF_EXPOSE_ENABLE) 813 ulp_notify = false; 814 else if (transport->state == SCTP_UNCONFIRMED && 815 error == SCTP_HEARTBEAT_SUCCESS) 816 spc_state = SCTP_ADDR_CONFIRMED; 817 818 transport->state = SCTP_ACTIVE; 819 sctp_transport_pl_reset(transport); 820 break; 821 822 case SCTP_TRANSPORT_DOWN: 823 /* If the transport was never confirmed, do not transition it 824 * to inactive state. Also, release the cached route since 825 * there may be a better route next time. 826 */ 827 if (transport->state != SCTP_UNCONFIRMED) { 828 transport->state = SCTP_INACTIVE; 829 sctp_transport_pl_reset(transport); 830 spc_state = SCTP_ADDR_UNREACHABLE; 831 } else { 832 sctp_transport_dst_release(transport); 833 ulp_notify = false; 834 } 835 break; 836 837 case SCTP_TRANSPORT_PF: 838 transport->state = SCTP_PF; 839 if (asoc->pf_expose != SCTP_PF_EXPOSE_ENABLE) 840 ulp_notify = false; 841 else 842 spc_state = SCTP_ADDR_POTENTIALLY_FAILED; 843 break; 844 845 default: 846 return; 847 } 848 849 /* Generate and send a SCTP_PEER_ADDR_CHANGE notification 850 * to the user. 851 */ 852 if (ulp_notify) 853 sctp_ulpevent_notify_peer_addr_change(transport, 854 spc_state, error); 855 856 /* Select new active and retran paths. */ 857 sctp_select_active_and_retran_path(asoc); 858 } 859 860 /* Hold a reference to an association. */ 861 void sctp_association_hold(struct sctp_association *asoc) 862 { 863 refcount_inc(&asoc->base.refcnt); 864 } 865 866 /* Release a reference to an association and cleanup 867 * if there are no more references. 868 */ 869 void sctp_association_put(struct sctp_association *asoc) 870 { 871 if (refcount_dec_and_test(&asoc->base.refcnt)) 872 sctp_association_destroy(asoc); 873 } 874 875 /* Allocate the next TSN, Transmission Sequence Number, for the given 876 * association. 877 */ 878 __u32 sctp_association_get_next_tsn(struct sctp_association *asoc) 879 { 880 /* From Section 1.6 Serial Number Arithmetic: 881 * Transmission Sequence Numbers wrap around when they reach 882 * 2**32 - 1. That is, the next TSN a DATA chunk MUST use 883 * after transmitting TSN = 2*32 - 1 is TSN = 0. 884 */ 885 __u32 retval = asoc->next_tsn; 886 asoc->next_tsn++; 887 asoc->unack_data++; 888 889 return retval; 890 } 891 892 /* Compare two addresses to see if they match. Wildcard addresses 893 * only match themselves. 894 */ 895 int sctp_cmp_addr_exact(const union sctp_addr *ss1, 896 const union sctp_addr *ss2) 897 { 898 struct sctp_af *af; 899 900 af = sctp_get_af_specific(ss1->sa.sa_family); 901 if (unlikely(!af)) 902 return 0; 903 904 return af->cmp_addr(ss1, ss2); 905 } 906 907 /* Return an ecne chunk to get prepended to a packet. 908 * Note: We are sly and return a shared, prealloced chunk. FIXME: 909 * No we don't, but we could/should. 910 */ 911 struct sctp_chunk *sctp_get_ecne_prepend(struct sctp_association *asoc) 912 { 913 if (!asoc->need_ecne) 914 return NULL; 915 916 /* Send ECNE if needed. 917 * Not being able to allocate a chunk here is not deadly. 918 */ 919 return sctp_make_ecne(asoc, asoc->last_ecne_tsn); 920 } 921 922 /* 923 * Find which transport this TSN was sent on. 924 */ 925 struct sctp_transport *sctp_assoc_lookup_tsn(struct sctp_association *asoc, 926 __u32 tsn) 927 { 928 struct sctp_transport *active; 929 struct sctp_transport *match; 930 struct sctp_transport *transport; 931 struct sctp_chunk *chunk; 932 __be32 key = htonl(tsn); 933 934 match = NULL; 935 936 /* 937 * FIXME: In general, find a more efficient data structure for 938 * searching. 939 */ 940 941 /* 942 * The general strategy is to search each transport's transmitted 943 * list. Return which transport this TSN lives on. 944 * 945 * Let's be hopeful and check the active_path first. 946 * Another optimization would be to know if there is only one 947 * outbound path and not have to look for the TSN at all. 948 * 949 */ 950 951 active = asoc->peer.active_path; 952 953 list_for_each_entry(chunk, &active->transmitted, 954 transmitted_list) { 955 956 if (key == chunk->subh.data_hdr->tsn) { 957 match = active; 958 goto out; 959 } 960 } 961 962 /* If not found, go search all the other transports. */ 963 list_for_each_entry(transport, &asoc->peer.transport_addr_list, 964 transports) { 965 966 if (transport == active) 967 continue; 968 list_for_each_entry(chunk, &transport->transmitted, 969 transmitted_list) { 970 if (key == chunk->subh.data_hdr->tsn) { 971 match = transport; 972 goto out; 973 } 974 } 975 } 976 out: 977 return match; 978 } 979 980 /* Do delayed input processing. This is scheduled by sctp_rcv(). */ 981 static void sctp_assoc_bh_rcv(struct work_struct *work) 982 { 983 struct sctp_association *asoc = 984 container_of(work, struct sctp_association, 985 base.inqueue.immediate); 986 struct net *net = asoc->base.net; 987 union sctp_subtype subtype; 988 struct sctp_endpoint *ep; 989 struct sctp_chunk *chunk; 990 struct sctp_inq *inqueue; 991 int first_time = 1; /* is this the first time through the loop */ 992 int error = 0; 993 int state; 994 995 /* The association should be held so we should be safe. */ 996 ep = asoc->ep; 997 998 inqueue = &asoc->base.inqueue; 999 sctp_association_hold(asoc); 1000 while (NULL != (chunk = sctp_inq_pop(inqueue))) { 1001 state = asoc->state; 1002 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type); 1003 1004 /* If the first chunk in the packet is AUTH, do special 1005 * processing specified in Section 6.3 of SCTP-AUTH spec 1006 */ 1007 if (first_time && subtype.chunk == SCTP_CID_AUTH) { 1008 struct sctp_chunkhdr *next_hdr; 1009 1010 next_hdr = sctp_inq_peek(inqueue); 1011 if (!next_hdr) 1012 goto normal; 1013 1014 /* If the next chunk is COOKIE-ECHO, skip the AUTH 1015 * chunk while saving a pointer to it so we can do 1016 * Authentication later (during cookie-echo 1017 * processing). 1018 */ 1019 if (next_hdr->type == SCTP_CID_COOKIE_ECHO) { 1020 chunk->auth_chunk = skb_clone(chunk->skb, 1021 GFP_ATOMIC); 1022 chunk->auth = 1; 1023 continue; 1024 } 1025 } 1026 1027 normal: 1028 /* SCTP-AUTH, Section 6.3: 1029 * The receiver has a list of chunk types which it expects 1030 * to be received only after an AUTH-chunk. This list has 1031 * been sent to the peer during the association setup. It 1032 * MUST silently discard these chunks if they are not placed 1033 * after an AUTH chunk in the packet. 1034 */ 1035 if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth) 1036 continue; 1037 1038 /* Remember where the last DATA chunk came from so we 1039 * know where to send the SACK. 1040 */ 1041 if (sctp_chunk_is_data(chunk)) 1042 asoc->peer.last_data_from = chunk->transport; 1043 else { 1044 SCTP_INC_STATS(net, SCTP_MIB_INCTRLCHUNKS); 1045 asoc->stats.ictrlchunks++; 1046 if (chunk->chunk_hdr->type == SCTP_CID_SACK) 1047 asoc->stats.isacks++; 1048 } 1049 1050 if (chunk->transport) 1051 chunk->transport->last_time_heard = ktime_get(); 1052 1053 /* Run through the state machine. */ 1054 error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, 1055 state, ep, asoc, chunk, GFP_ATOMIC); 1056 1057 /* Check to see if the association is freed in response to 1058 * the incoming chunk. If so, get out of the while loop. 1059 */ 1060 if (asoc->base.dead) 1061 break; 1062 1063 /* If there is an error on chunk, discard this packet. */ 1064 if (error && chunk) 1065 chunk->pdiscard = 1; 1066 1067 if (first_time) 1068 first_time = 0; 1069 } 1070 sctp_association_put(asoc); 1071 } 1072 1073 /* This routine moves an association from its old sk to a new sk. */ 1074 void sctp_assoc_migrate(struct sctp_association *assoc, struct sock *newsk) 1075 { 1076 struct sctp_sock *newsp = sctp_sk(newsk); 1077 struct sock *oldsk = assoc->base.sk; 1078 1079 /* Delete the association from the old endpoint's list of 1080 * associations. 1081 */ 1082 list_del_init(&assoc->asocs); 1083 1084 /* Decrement the backlog value for a TCP-style socket. */ 1085 if (sctp_style(oldsk, TCP)) 1086 sk_acceptq_removed(oldsk); 1087 1088 /* Release references to the old endpoint and the sock. */ 1089 sctp_endpoint_put(assoc->ep); 1090 sock_put(assoc->base.sk); 1091 1092 /* Get a reference to the new endpoint. */ 1093 assoc->ep = newsp->ep; 1094 sctp_endpoint_hold(assoc->ep); 1095 1096 /* Get a reference to the new sock. */ 1097 assoc->base.sk = newsk; 1098 sock_hold(assoc->base.sk); 1099 1100 /* Add the association to the new endpoint's list of associations. */ 1101 sctp_endpoint_add_asoc(newsp->ep, assoc); 1102 } 1103 1104 /* Update an association (possibly from unexpected COOKIE-ECHO processing). */ 1105 int sctp_assoc_update(struct sctp_association *asoc, 1106 struct sctp_association *new) 1107 { 1108 struct sctp_transport *trans; 1109 struct list_head *pos, *temp; 1110 1111 /* Copy in new parameters of peer. */ 1112 asoc->c = new->c; 1113 asoc->peer.rwnd = new->peer.rwnd; 1114 asoc->peer.sack_needed = new->peer.sack_needed; 1115 asoc->peer.auth_capable = new->peer.auth_capable; 1116 asoc->peer.i = new->peer.i; 1117 1118 if (!sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL, 1119 asoc->peer.i.initial_tsn, GFP_ATOMIC)) 1120 return -ENOMEM; 1121 1122 /* Remove any peer addresses not present in the new association. */ 1123 list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) { 1124 trans = list_entry(pos, struct sctp_transport, transports); 1125 if (!sctp_assoc_lookup_paddr(new, &trans->ipaddr)) { 1126 sctp_assoc_rm_peer(asoc, trans); 1127 continue; 1128 } 1129 1130 if (asoc->state >= SCTP_STATE_ESTABLISHED) 1131 sctp_transport_reset(trans); 1132 } 1133 1134 /* If the case is A (association restart), use 1135 * initial_tsn as next_tsn. If the case is B, use 1136 * current next_tsn in case data sent to peer 1137 * has been discarded and needs retransmission. 1138 */ 1139 if (asoc->state >= SCTP_STATE_ESTABLISHED) { 1140 asoc->next_tsn = new->next_tsn; 1141 asoc->ctsn_ack_point = new->ctsn_ack_point; 1142 asoc->adv_peer_ack_point = new->adv_peer_ack_point; 1143 1144 /* Reinitialize SSN for both local streams 1145 * and peer's streams. 1146 */ 1147 sctp_stream_clear(&asoc->stream); 1148 1149 /* Flush the ULP reassembly and ordered queue. 1150 * Any data there will now be stale and will 1151 * cause problems. 1152 */ 1153 sctp_ulpq_flush(&asoc->ulpq); 1154 1155 /* reset the overall association error count so 1156 * that the restarted association doesn't get torn 1157 * down on the next retransmission timer. 1158 */ 1159 asoc->overall_error_count = 0; 1160 1161 } else { 1162 /* Add any peer addresses from the new association. */ 1163 list_for_each_entry(trans, &new->peer.transport_addr_list, 1164 transports) 1165 if (!sctp_assoc_lookup_paddr(asoc, &trans->ipaddr) && 1166 !sctp_assoc_add_peer(asoc, &trans->ipaddr, 1167 GFP_ATOMIC, trans->state)) 1168 return -ENOMEM; 1169 1170 asoc->ctsn_ack_point = asoc->next_tsn - 1; 1171 asoc->adv_peer_ack_point = asoc->ctsn_ack_point; 1172 1173 if (sctp_state(asoc, COOKIE_WAIT)) 1174 sctp_stream_update(&asoc->stream, &new->stream); 1175 1176 /* get a new assoc id if we don't have one yet. */ 1177 if (sctp_assoc_set_id(asoc, GFP_ATOMIC)) 1178 return -ENOMEM; 1179 } 1180 1181 /* SCTP-AUTH: Save the peer parameters from the new associations 1182 * and also move the association shared keys over 1183 */ 1184 kfree(asoc->peer.peer_random); 1185 asoc->peer.peer_random = new->peer.peer_random; 1186 new->peer.peer_random = NULL; 1187 1188 kfree(asoc->peer.peer_chunks); 1189 asoc->peer.peer_chunks = new->peer.peer_chunks; 1190 new->peer.peer_chunks = NULL; 1191 1192 kfree(asoc->peer.peer_hmacs); 1193 asoc->peer.peer_hmacs = new->peer.peer_hmacs; 1194 new->peer.peer_hmacs = NULL; 1195 1196 return sctp_auth_asoc_init_active_key(asoc, GFP_ATOMIC); 1197 } 1198 1199 /* Update the retran path for sending a retransmitted packet. 1200 * See also RFC4960, 6.4. Multi-Homed SCTP Endpoints: 1201 * 1202 * When there is outbound data to send and the primary path 1203 * becomes inactive (e.g., due to failures), or where the 1204 * SCTP user explicitly requests to send data to an 1205 * inactive destination transport address, before reporting 1206 * an error to its ULP, the SCTP endpoint should try to send 1207 * the data to an alternate active destination transport 1208 * address if one exists. 1209 * 1210 * When retransmitting data that timed out, if the endpoint 1211 * is multihomed, it should consider each source-destination 1212 * address pair in its retransmission selection policy. 1213 * When retransmitting timed-out data, the endpoint should 1214 * attempt to pick the most divergent source-destination 1215 * pair from the original source-destination pair to which 1216 * the packet was transmitted. 1217 * 1218 * Note: Rules for picking the most divergent source-destination 1219 * pair are an implementation decision and are not specified 1220 * within this document. 1221 * 1222 * Our basic strategy is to round-robin transports in priorities 1223 * according to sctp_trans_score() e.g., if no such 1224 * transport with state SCTP_ACTIVE exists, round-robin through 1225 * SCTP_UNKNOWN, etc. You get the picture. 1226 */ 1227 static u8 sctp_trans_score(const struct sctp_transport *trans) 1228 { 1229 switch (trans->state) { 1230 case SCTP_ACTIVE: 1231 return 3; /* best case */ 1232 case SCTP_UNKNOWN: 1233 return 2; 1234 case SCTP_PF: 1235 return 1; 1236 default: /* case SCTP_INACTIVE */ 1237 return 0; /* worst case */ 1238 } 1239 } 1240 1241 static struct sctp_transport *sctp_trans_elect_tie(struct sctp_transport *trans1, 1242 struct sctp_transport *trans2) 1243 { 1244 if (trans1->error_count > trans2->error_count) { 1245 return trans2; 1246 } else if (trans1->error_count == trans2->error_count && 1247 ktime_after(trans2->last_time_heard, 1248 trans1->last_time_heard)) { 1249 return trans2; 1250 } else { 1251 return trans1; 1252 } 1253 } 1254 1255 static struct sctp_transport *sctp_trans_elect_best(struct sctp_transport *curr, 1256 struct sctp_transport *best) 1257 { 1258 u8 score_curr, score_best; 1259 1260 if (best == NULL || curr == best) 1261 return curr; 1262 1263 score_curr = sctp_trans_score(curr); 1264 score_best = sctp_trans_score(best); 1265 1266 /* First, try a score-based selection if both transport states 1267 * differ. If we're in a tie, lets try to make a more clever 1268 * decision here based on error counts and last time heard. 1269 */ 1270 if (score_curr > score_best) 1271 return curr; 1272 else if (score_curr == score_best) 1273 return sctp_trans_elect_tie(best, curr); 1274 else 1275 return best; 1276 } 1277 1278 void sctp_assoc_update_retran_path(struct sctp_association *asoc) 1279 { 1280 struct sctp_transport *trans = asoc->peer.retran_path; 1281 struct sctp_transport *trans_next = NULL; 1282 1283 /* We're done as we only have the one and only path. */ 1284 if (asoc->peer.transport_count == 1) 1285 return; 1286 /* If active_path and retran_path are the same and active, 1287 * then this is the only active path. Use it. 1288 */ 1289 if (asoc->peer.active_path == asoc->peer.retran_path && 1290 asoc->peer.active_path->state == SCTP_ACTIVE) 1291 return; 1292 1293 /* Iterate from retran_path's successor back to retran_path. */ 1294 for (trans = list_next_entry(trans, transports); 1; 1295 trans = list_next_entry(trans, transports)) { 1296 /* Manually skip the head element. */ 1297 if (&trans->transports == &asoc->peer.transport_addr_list) 1298 continue; 1299 if (trans->state == SCTP_UNCONFIRMED) 1300 continue; 1301 trans_next = sctp_trans_elect_best(trans, trans_next); 1302 /* Active is good enough for immediate return. */ 1303 if (trans_next->state == SCTP_ACTIVE) 1304 break; 1305 /* We've reached the end, time to update path. */ 1306 if (trans == asoc->peer.retran_path) 1307 break; 1308 } 1309 1310 asoc->peer.retran_path = trans_next; 1311 1312 pr_debug("%s: association:%p updated new path to addr:%pISpc\n", 1313 __func__, asoc, &asoc->peer.retran_path->ipaddr.sa); 1314 } 1315 1316 static void sctp_select_active_and_retran_path(struct sctp_association *asoc) 1317 { 1318 struct sctp_transport *trans, *trans_pri = NULL, *trans_sec = NULL; 1319 struct sctp_transport *trans_pf = NULL; 1320 1321 /* Look for the two most recently used active transports. */ 1322 list_for_each_entry(trans, &asoc->peer.transport_addr_list, 1323 transports) { 1324 /* Skip uninteresting transports. */ 1325 if (trans->state == SCTP_INACTIVE || 1326 trans->state == SCTP_UNCONFIRMED) 1327 continue; 1328 /* Keep track of the best PF transport from our 1329 * list in case we don't find an active one. 1330 */ 1331 if (trans->state == SCTP_PF) { 1332 trans_pf = sctp_trans_elect_best(trans, trans_pf); 1333 continue; 1334 } 1335 /* For active transports, pick the most recent ones. */ 1336 if (trans_pri == NULL || 1337 ktime_after(trans->last_time_heard, 1338 trans_pri->last_time_heard)) { 1339 trans_sec = trans_pri; 1340 trans_pri = trans; 1341 } else if (trans_sec == NULL || 1342 ktime_after(trans->last_time_heard, 1343 trans_sec->last_time_heard)) { 1344 trans_sec = trans; 1345 } 1346 } 1347 1348 /* RFC 2960 6.4 Multi-Homed SCTP Endpoints 1349 * 1350 * By default, an endpoint should always transmit to the primary 1351 * path, unless the SCTP user explicitly specifies the 1352 * destination transport address (and possibly source transport 1353 * address) to use. [If the primary is active but not most recent, 1354 * bump the most recently used transport.] 1355 */ 1356 if ((asoc->peer.primary_path->state == SCTP_ACTIVE || 1357 asoc->peer.primary_path->state == SCTP_UNKNOWN) && 1358 asoc->peer.primary_path != trans_pri) { 1359 trans_sec = trans_pri; 1360 trans_pri = asoc->peer.primary_path; 1361 } 1362 1363 /* We did not find anything useful for a possible retransmission 1364 * path; either primary path that we found is the same as 1365 * the current one, or we didn't generally find an active one. 1366 */ 1367 if (trans_sec == NULL) 1368 trans_sec = trans_pri; 1369 1370 /* If we failed to find a usable transport, just camp on the 1371 * active or pick a PF iff it's the better choice. 1372 */ 1373 if (trans_pri == NULL) { 1374 trans_pri = sctp_trans_elect_best(asoc->peer.active_path, trans_pf); 1375 trans_sec = trans_pri; 1376 } 1377 1378 /* Set the active and retran transports. */ 1379 asoc->peer.active_path = trans_pri; 1380 asoc->peer.retran_path = trans_sec; 1381 } 1382 1383 struct sctp_transport * 1384 sctp_assoc_choose_alter_transport(struct sctp_association *asoc, 1385 struct sctp_transport *last_sent_to) 1386 { 1387 /* If this is the first time packet is sent, use the active path, 1388 * else use the retran path. If the last packet was sent over the 1389 * retran path, update the retran path and use it. 1390 */ 1391 if (last_sent_to == NULL) { 1392 return asoc->peer.active_path; 1393 } else { 1394 if (last_sent_to == asoc->peer.retran_path) 1395 sctp_assoc_update_retran_path(asoc); 1396 1397 return asoc->peer.retran_path; 1398 } 1399 } 1400 1401 void sctp_assoc_update_frag_point(struct sctp_association *asoc) 1402 { 1403 int frag = sctp_mtu_payload(sctp_sk(asoc->base.sk), asoc->pathmtu, 1404 sctp_datachk_len(&asoc->stream)); 1405 1406 if (asoc->user_frag) 1407 frag = min_t(int, frag, asoc->user_frag); 1408 1409 frag = min_t(int, frag, SCTP_MAX_CHUNK_LEN - 1410 sctp_datachk_len(&asoc->stream)); 1411 1412 asoc->frag_point = SCTP_TRUNC4(frag); 1413 } 1414 1415 void sctp_assoc_set_pmtu(struct sctp_association *asoc, __u32 pmtu) 1416 { 1417 if (asoc->pathmtu != pmtu) { 1418 asoc->pathmtu = pmtu; 1419 sctp_assoc_update_frag_point(asoc); 1420 } 1421 1422 pr_debug("%s: asoc:%p, pmtu:%d, frag_point:%d\n", __func__, asoc, 1423 asoc->pathmtu, asoc->frag_point); 1424 } 1425 1426 /* Update the association's pmtu and frag_point by going through all the 1427 * transports. This routine is called when a transport's PMTU has changed. 1428 */ 1429 void sctp_assoc_sync_pmtu(struct sctp_association *asoc) 1430 { 1431 struct sctp_transport *t; 1432 __u32 pmtu = 0; 1433 1434 if (!asoc) 1435 return; 1436 1437 /* Get the lowest pmtu of all the transports. */ 1438 list_for_each_entry(t, &asoc->peer.transport_addr_list, transports) { 1439 if (t->pmtu_pending && t->dst) { 1440 sctp_transport_update_pmtu(t, 1441 atomic_read(&t->mtu_info)); 1442 t->pmtu_pending = 0; 1443 } 1444 if (!pmtu || (t->pathmtu < pmtu)) 1445 pmtu = t->pathmtu; 1446 } 1447 1448 sctp_assoc_set_pmtu(asoc, pmtu); 1449 } 1450 1451 /* Should we send a SACK to update our peer? */ 1452 static inline bool sctp_peer_needs_update(struct sctp_association *asoc) 1453 { 1454 struct net *net = asoc->base.net; 1455 1456 switch (asoc->state) { 1457 case SCTP_STATE_ESTABLISHED: 1458 case SCTP_STATE_SHUTDOWN_PENDING: 1459 case SCTP_STATE_SHUTDOWN_RECEIVED: 1460 case SCTP_STATE_SHUTDOWN_SENT: 1461 if ((asoc->rwnd > asoc->a_rwnd) && 1462 ((asoc->rwnd - asoc->a_rwnd) >= max_t(__u32, 1463 (asoc->base.sk->sk_rcvbuf >> net->sctp.rwnd_upd_shift), 1464 asoc->pathmtu))) 1465 return true; 1466 break; 1467 default: 1468 break; 1469 } 1470 return false; 1471 } 1472 1473 /* Increase asoc's rwnd by len and send any window update SACK if needed. */ 1474 void sctp_assoc_rwnd_increase(struct sctp_association *asoc, unsigned int len) 1475 { 1476 struct sctp_chunk *sack; 1477 struct timer_list *timer; 1478 1479 if (asoc->rwnd_over) { 1480 if (asoc->rwnd_over >= len) { 1481 asoc->rwnd_over -= len; 1482 } else { 1483 asoc->rwnd += (len - asoc->rwnd_over); 1484 asoc->rwnd_over = 0; 1485 } 1486 } else { 1487 asoc->rwnd += len; 1488 } 1489 1490 /* If we had window pressure, start recovering it 1491 * once our rwnd had reached the accumulated pressure 1492 * threshold. The idea is to recover slowly, but up 1493 * to the initial advertised window. 1494 */ 1495 if (asoc->rwnd_press) { 1496 int change = min(asoc->pathmtu, asoc->rwnd_press); 1497 asoc->rwnd += change; 1498 asoc->rwnd_press -= change; 1499 } 1500 1501 pr_debug("%s: asoc:%p rwnd increased by %d to (%u, %u) - %u\n", 1502 __func__, asoc, len, asoc->rwnd, asoc->rwnd_over, 1503 asoc->a_rwnd); 1504 1505 /* Send a window update SACK if the rwnd has increased by at least the 1506 * minimum of the association's PMTU and half of the receive buffer. 1507 * The algorithm used is similar to the one described in 1508 * Section 4.2.3.3 of RFC 1122. 1509 */ 1510 if (sctp_peer_needs_update(asoc)) { 1511 asoc->a_rwnd = asoc->rwnd; 1512 1513 pr_debug("%s: sending window update SACK- asoc:%p rwnd:%u " 1514 "a_rwnd:%u\n", __func__, asoc, asoc->rwnd, 1515 asoc->a_rwnd); 1516 1517 sack = sctp_make_sack(asoc); 1518 if (!sack) 1519 return; 1520 1521 asoc->peer.sack_needed = 0; 1522 1523 sctp_outq_tail(&asoc->outqueue, sack, GFP_ATOMIC); 1524 1525 /* Stop the SACK timer. */ 1526 timer = &asoc->timers[SCTP_EVENT_TIMEOUT_SACK]; 1527 if (del_timer(timer)) 1528 sctp_association_put(asoc); 1529 } 1530 } 1531 1532 /* Decrease asoc's rwnd by len. */ 1533 void sctp_assoc_rwnd_decrease(struct sctp_association *asoc, unsigned int len) 1534 { 1535 int rx_count; 1536 int over = 0; 1537 1538 if (unlikely(!asoc->rwnd || asoc->rwnd_over)) 1539 pr_debug("%s: association:%p has asoc->rwnd:%u, " 1540 "asoc->rwnd_over:%u!\n", __func__, asoc, 1541 asoc->rwnd, asoc->rwnd_over); 1542 1543 if (asoc->ep->rcvbuf_policy) 1544 rx_count = atomic_read(&asoc->rmem_alloc); 1545 else 1546 rx_count = atomic_read(&asoc->base.sk->sk_rmem_alloc); 1547 1548 /* If we've reached or overflowed our receive buffer, announce 1549 * a 0 rwnd if rwnd would still be positive. Store the 1550 * potential pressure overflow so that the window can be restored 1551 * back to original value. 1552 */ 1553 if (rx_count >= asoc->base.sk->sk_rcvbuf) 1554 over = 1; 1555 1556 if (asoc->rwnd >= len) { 1557 asoc->rwnd -= len; 1558 if (over) { 1559 asoc->rwnd_press += asoc->rwnd; 1560 asoc->rwnd = 0; 1561 } 1562 } else { 1563 asoc->rwnd_over += len - asoc->rwnd; 1564 asoc->rwnd = 0; 1565 } 1566 1567 pr_debug("%s: asoc:%p rwnd decreased by %d to (%u, %u, %u)\n", 1568 __func__, asoc, len, asoc->rwnd, asoc->rwnd_over, 1569 asoc->rwnd_press); 1570 } 1571 1572 /* Build the bind address list for the association based on info from the 1573 * local endpoint and the remote peer. 1574 */ 1575 int sctp_assoc_set_bind_addr_from_ep(struct sctp_association *asoc, 1576 enum sctp_scope scope, gfp_t gfp) 1577 { 1578 struct sock *sk = asoc->base.sk; 1579 int flags; 1580 1581 /* Use scoping rules to determine the subset of addresses from 1582 * the endpoint. 1583 */ 1584 flags = (PF_INET6 == sk->sk_family) ? SCTP_ADDR6_ALLOWED : 0; 1585 if (!inet_v6_ipv6only(sk)) 1586 flags |= SCTP_ADDR4_ALLOWED; 1587 if (asoc->peer.ipv4_address) 1588 flags |= SCTP_ADDR4_PEERSUPP; 1589 if (asoc->peer.ipv6_address) 1590 flags |= SCTP_ADDR6_PEERSUPP; 1591 1592 return sctp_bind_addr_copy(asoc->base.net, 1593 &asoc->base.bind_addr, 1594 &asoc->ep->base.bind_addr, 1595 scope, gfp, flags); 1596 } 1597 1598 /* Build the association's bind address list from the cookie. */ 1599 int sctp_assoc_set_bind_addr_from_cookie(struct sctp_association *asoc, 1600 struct sctp_cookie *cookie, 1601 gfp_t gfp) 1602 { 1603 int var_size2 = ntohs(cookie->peer_init->chunk_hdr.length); 1604 int var_size3 = cookie->raw_addr_list_len; 1605 __u8 *raw = (__u8 *)cookie->peer_init + var_size2; 1606 1607 return sctp_raw_to_bind_addrs(&asoc->base.bind_addr, raw, var_size3, 1608 asoc->ep->base.bind_addr.port, gfp); 1609 } 1610 1611 /* Lookup laddr in the bind address list of an association. */ 1612 int sctp_assoc_lookup_laddr(struct sctp_association *asoc, 1613 const union sctp_addr *laddr) 1614 { 1615 int found = 0; 1616 1617 if ((asoc->base.bind_addr.port == ntohs(laddr->v4.sin_port)) && 1618 sctp_bind_addr_match(&asoc->base.bind_addr, laddr, 1619 sctp_sk(asoc->base.sk))) 1620 found = 1; 1621 1622 return found; 1623 } 1624 1625 /* Set an association id for a given association */ 1626 int sctp_assoc_set_id(struct sctp_association *asoc, gfp_t gfp) 1627 { 1628 bool preload = gfpflags_allow_blocking(gfp); 1629 int ret; 1630 1631 /* If the id is already assigned, keep it. */ 1632 if (asoc->assoc_id) 1633 return 0; 1634 1635 if (preload) 1636 idr_preload(gfp); 1637 spin_lock_bh(&sctp_assocs_id_lock); 1638 /* 0, 1, 2 are used as SCTP_FUTURE_ASSOC, SCTP_CURRENT_ASSOC and 1639 * SCTP_ALL_ASSOC, so an available id must be > SCTP_ALL_ASSOC. 1640 */ 1641 ret = idr_alloc_cyclic(&sctp_assocs_id, asoc, SCTP_ALL_ASSOC + 1, 0, 1642 GFP_NOWAIT); 1643 spin_unlock_bh(&sctp_assocs_id_lock); 1644 if (preload) 1645 idr_preload_end(); 1646 if (ret < 0) 1647 return ret; 1648 1649 asoc->assoc_id = (sctp_assoc_t)ret; 1650 return 0; 1651 } 1652 1653 /* Free the ASCONF queue */ 1654 static void sctp_assoc_free_asconf_queue(struct sctp_association *asoc) 1655 { 1656 struct sctp_chunk *asconf; 1657 struct sctp_chunk *tmp; 1658 1659 list_for_each_entry_safe(asconf, tmp, &asoc->addip_chunk_list, list) { 1660 list_del_init(&asconf->list); 1661 sctp_chunk_free(asconf); 1662 } 1663 } 1664 1665 /* Free asconf_ack cache */ 1666 static void sctp_assoc_free_asconf_acks(struct sctp_association *asoc) 1667 { 1668 struct sctp_chunk *ack; 1669 struct sctp_chunk *tmp; 1670 1671 list_for_each_entry_safe(ack, tmp, &asoc->asconf_ack_list, 1672 transmitted_list) { 1673 list_del_init(&ack->transmitted_list); 1674 sctp_chunk_free(ack); 1675 } 1676 } 1677 1678 /* Clean up the ASCONF_ACK queue */ 1679 void sctp_assoc_clean_asconf_ack_cache(const struct sctp_association *asoc) 1680 { 1681 struct sctp_chunk *ack; 1682 struct sctp_chunk *tmp; 1683 1684 /* We can remove all the entries from the queue up to 1685 * the "Peer-Sequence-Number". 1686 */ 1687 list_for_each_entry_safe(ack, tmp, &asoc->asconf_ack_list, 1688 transmitted_list) { 1689 if (ack->subh.addip_hdr->serial == 1690 htonl(asoc->peer.addip_serial)) 1691 break; 1692 1693 list_del_init(&ack->transmitted_list); 1694 sctp_chunk_free(ack); 1695 } 1696 } 1697 1698 /* Find the ASCONF_ACK whose serial number matches ASCONF */ 1699 struct sctp_chunk *sctp_assoc_lookup_asconf_ack( 1700 const struct sctp_association *asoc, 1701 __be32 serial) 1702 { 1703 struct sctp_chunk *ack; 1704 1705 /* Walk through the list of cached ASCONF-ACKs and find the 1706 * ack chunk whose serial number matches that of the request. 1707 */ 1708 list_for_each_entry(ack, &asoc->asconf_ack_list, transmitted_list) { 1709 if (sctp_chunk_pending(ack)) 1710 continue; 1711 if (ack->subh.addip_hdr->serial == serial) { 1712 sctp_chunk_hold(ack); 1713 return ack; 1714 } 1715 } 1716 1717 return NULL; 1718 } 1719 1720 void sctp_asconf_queue_teardown(struct sctp_association *asoc) 1721 { 1722 /* Free any cached ASCONF_ACK chunk. */ 1723 sctp_assoc_free_asconf_acks(asoc); 1724 1725 /* Free the ASCONF queue. */ 1726 sctp_assoc_free_asconf_queue(asoc); 1727 1728 /* Free any cached ASCONF chunk. */ 1729 if (asoc->addip_last_asconf) 1730 sctp_chunk_free(asoc->addip_last_asconf); 1731 } 1732