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