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