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