1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* SCTP kernel implementation 3 * (C) Copyright IBM Corp. 2001, 2004 4 * Copyright (c) 1999 Cisco, Inc. 5 * Copyright (c) 1999-2001 Motorola, Inc. 6 * 7 * This file is part of the SCTP kernel implementation 8 * 9 * These functions work with the state functions in sctp_sm_statefuns.c 10 * to implement that state operations. These functions implement the 11 * steps which require modifying existing data structures. 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@austin.ibm.com> 21 * Hui Huang <hui.huang@nokia.com> 22 * Dajiang Zhang <dajiang.zhang@nokia.com> 23 * Daisy Chang <daisyc@us.ibm.com> 24 * Sridhar Samudrala <sri@us.ibm.com> 25 * Ardelle Fan <ardelle.fan@intel.com> 26 */ 27 28 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 29 30 #include <linux/skbuff.h> 31 #include <linux/types.h> 32 #include <linux/socket.h> 33 #include <linux/ip.h> 34 #include <linux/gfp.h> 35 #include <net/sock.h> 36 #include <net/sctp/sctp.h> 37 #include <net/sctp/sm.h> 38 #include <net/sctp/stream_sched.h> 39 40 static int sctp_cmd_interpreter(enum sctp_event_type event_type, 41 union sctp_subtype subtype, 42 enum sctp_state state, 43 struct sctp_endpoint *ep, 44 struct sctp_association *asoc, 45 void *event_arg, 46 enum sctp_disposition status, 47 struct sctp_cmd_seq *commands, 48 gfp_t gfp); 49 static int sctp_side_effects(enum sctp_event_type event_type, 50 union sctp_subtype subtype, 51 enum sctp_state state, 52 struct sctp_endpoint *ep, 53 struct sctp_association **asoc, 54 void *event_arg, 55 enum sctp_disposition status, 56 struct sctp_cmd_seq *commands, 57 gfp_t gfp); 58 59 /******************************************************************** 60 * Helper functions 61 ********************************************************************/ 62 63 /* A helper function for delayed processing of INET ECN CE bit. */ 64 static void sctp_do_ecn_ce_work(struct sctp_association *asoc, 65 __u32 lowest_tsn) 66 { 67 /* Save the TSN away for comparison when we receive CWR */ 68 69 asoc->last_ecne_tsn = lowest_tsn; 70 asoc->need_ecne = 1; 71 } 72 73 /* Helper function for delayed processing of SCTP ECNE chunk. */ 74 /* RFC 2960 Appendix A 75 * 76 * RFC 2481 details a specific bit for a sender to send in 77 * the header of its next outbound TCP segment to indicate to 78 * its peer that it has reduced its congestion window. This 79 * is termed the CWR bit. For SCTP the same indication is made 80 * by including the CWR chunk. This chunk contains one data 81 * element, i.e. the TSN number that was sent in the ECNE chunk. 82 * This element represents the lowest TSN number in the datagram 83 * that was originally marked with the CE bit. 84 */ 85 static struct sctp_chunk *sctp_do_ecn_ecne_work(struct sctp_association *asoc, 86 __u32 lowest_tsn, 87 struct sctp_chunk *chunk) 88 { 89 struct sctp_chunk *repl; 90 91 /* Our previously transmitted packet ran into some congestion 92 * so we should take action by reducing cwnd and ssthresh 93 * and then ACK our peer that we we've done so by 94 * sending a CWR. 95 */ 96 97 /* First, try to determine if we want to actually lower 98 * our cwnd variables. Only lower them if the ECNE looks more 99 * recent than the last response. 100 */ 101 if (TSN_lt(asoc->last_cwr_tsn, lowest_tsn)) { 102 struct sctp_transport *transport; 103 104 /* Find which transport's congestion variables 105 * need to be adjusted. 106 */ 107 transport = sctp_assoc_lookup_tsn(asoc, lowest_tsn); 108 109 /* Update the congestion variables. */ 110 if (transport) 111 sctp_transport_lower_cwnd(transport, 112 SCTP_LOWER_CWND_ECNE); 113 asoc->last_cwr_tsn = lowest_tsn; 114 } 115 116 /* Always try to quiet the other end. In case of lost CWR, 117 * resend last_cwr_tsn. 118 */ 119 repl = sctp_make_cwr(asoc, asoc->last_cwr_tsn, chunk); 120 121 /* If we run out of memory, it will look like a lost CWR. We'll 122 * get back in sync eventually. 123 */ 124 return repl; 125 } 126 127 /* Helper function to do delayed processing of ECN CWR chunk. */ 128 static void sctp_do_ecn_cwr_work(struct sctp_association *asoc, 129 __u32 lowest_tsn) 130 { 131 /* Turn off ECNE getting auto-prepended to every outgoing 132 * packet 133 */ 134 asoc->need_ecne = 0; 135 } 136 137 /* Generate SACK if necessary. We call this at the end of a packet. */ 138 static int sctp_gen_sack(struct sctp_association *asoc, int force, 139 struct sctp_cmd_seq *commands) 140 { 141 struct sctp_transport *trans = asoc->peer.last_data_from; 142 __u32 ctsn, max_tsn_seen; 143 struct sctp_chunk *sack; 144 int error = 0; 145 146 if (force || 147 (!trans && (asoc->param_flags & SPP_SACKDELAY_DISABLE)) || 148 (trans && (trans->param_flags & SPP_SACKDELAY_DISABLE))) 149 asoc->peer.sack_needed = 1; 150 151 ctsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map); 152 max_tsn_seen = sctp_tsnmap_get_max_tsn_seen(&asoc->peer.tsn_map); 153 154 /* From 12.2 Parameters necessary per association (i.e. the TCB): 155 * 156 * Ack State : This flag indicates if the next received packet 157 * : is to be responded to with a SACK. ... 158 * : When DATA chunks are out of order, SACK's 159 * : are not delayed (see Section 6). 160 * 161 * [This is actually not mentioned in Section 6, but we 162 * implement it here anyway. --piggy] 163 */ 164 if (max_tsn_seen != ctsn) 165 asoc->peer.sack_needed = 1; 166 167 /* From 6.2 Acknowledgement on Reception of DATA Chunks: 168 * 169 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, 170 * an acknowledgement SHOULD be generated for at least every 171 * second packet (not every second DATA chunk) received, and 172 * SHOULD be generated within 200 ms of the arrival of any 173 * unacknowledged DATA chunk. ... 174 */ 175 if (!asoc->peer.sack_needed) { 176 asoc->peer.sack_cnt++; 177 178 /* Set the SACK delay timeout based on the 179 * SACK delay for the last transport 180 * data was received from, or the default 181 * for the association. 182 */ 183 if (trans) { 184 /* We will need a SACK for the next packet. */ 185 if (asoc->peer.sack_cnt >= trans->sackfreq - 1) 186 asoc->peer.sack_needed = 1; 187 188 asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] = 189 trans->sackdelay; 190 } else { 191 /* We will need a SACK for the next packet. */ 192 if (asoc->peer.sack_cnt >= asoc->sackfreq - 1) 193 asoc->peer.sack_needed = 1; 194 195 asoc->timeouts[SCTP_EVENT_TIMEOUT_SACK] = 196 asoc->sackdelay; 197 } 198 199 /* Restart the SACK timer. */ 200 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 201 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); 202 } else { 203 __u32 old_a_rwnd = asoc->a_rwnd; 204 205 asoc->a_rwnd = asoc->rwnd; 206 sack = sctp_make_sack(asoc); 207 if (!sack) { 208 asoc->a_rwnd = old_a_rwnd; 209 goto nomem; 210 } 211 212 asoc->peer.sack_needed = 0; 213 asoc->peer.sack_cnt = 0; 214 215 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(sack)); 216 217 /* Stop the SACK timer. */ 218 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 219 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); 220 } 221 222 return error; 223 nomem: 224 error = -ENOMEM; 225 return error; 226 } 227 228 /* When the T3-RTX timer expires, it calls this function to create the 229 * relevant state machine event. 230 */ 231 void sctp_generate_t3_rtx_event(struct timer_list *t) 232 { 233 struct sctp_transport *transport = 234 timer_container_of(transport, t, T3_rtx_timer); 235 struct sctp_association *asoc = transport->asoc; 236 struct sock *sk = asoc->base.sk; 237 struct net *net = sock_net(sk); 238 int error; 239 240 /* Check whether a task is in the sock. */ 241 242 bh_lock_sock(sk); 243 if (sock_owned_by_user(sk)) { 244 pr_debug("%s: sock is busy\n", __func__); 245 246 /* Try again later. */ 247 if (!mod_timer(&transport->T3_rtx_timer, jiffies + (HZ/20))) 248 sctp_transport_hold(transport); 249 goto out_unlock; 250 } 251 252 /* Run through the state machine. */ 253 error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT, 254 SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_T3_RTX), 255 asoc->state, 256 asoc->ep, asoc, 257 transport, GFP_ATOMIC); 258 259 if (error) 260 sk->sk_err = -error; 261 262 out_unlock: 263 bh_unlock_sock(sk); 264 sctp_transport_put(transport); 265 } 266 267 /* This is a sa interface for producing timeout events. It works 268 * for timeouts which use the association as their parameter. 269 */ 270 static void sctp_generate_timeout_event(struct sctp_association *asoc, 271 enum sctp_event_timeout timeout_type) 272 { 273 struct sock *sk = asoc->base.sk; 274 struct net *net = sock_net(sk); 275 int error = 0; 276 277 bh_lock_sock(sk); 278 if (sock_owned_by_user(sk)) { 279 pr_debug("%s: sock is busy: timer %d\n", __func__, 280 timeout_type); 281 282 /* Try again later. */ 283 if (!mod_timer(&asoc->timers[timeout_type], jiffies + (HZ/20))) 284 sctp_association_hold(asoc); 285 goto out_unlock; 286 } 287 288 /* Is this association really dead and just waiting around for 289 * the timer to let go of the reference? 290 */ 291 if (asoc->base.dead) 292 goto out_unlock; 293 294 /* Run through the state machine. */ 295 error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT, 296 SCTP_ST_TIMEOUT(timeout_type), 297 asoc->state, asoc->ep, asoc, 298 (void *)timeout_type, GFP_ATOMIC); 299 300 if (error) 301 sk->sk_err = -error; 302 303 out_unlock: 304 bh_unlock_sock(sk); 305 sctp_association_put(asoc); 306 } 307 308 static void sctp_generate_t1_cookie_event(struct timer_list *t) 309 { 310 struct sctp_association *asoc = 311 timer_container_of(asoc, t, 312 timers[SCTP_EVENT_TIMEOUT_T1_COOKIE]); 313 314 sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_COOKIE); 315 } 316 317 static void sctp_generate_t1_init_event(struct timer_list *t) 318 { 319 struct sctp_association *asoc = 320 timer_container_of(asoc, t, 321 timers[SCTP_EVENT_TIMEOUT_T1_INIT]); 322 323 sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T1_INIT); 324 } 325 326 static void sctp_generate_t2_shutdown_event(struct timer_list *t) 327 { 328 struct sctp_association *asoc = 329 timer_container_of(asoc, t, 330 timers[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN]); 331 332 sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T2_SHUTDOWN); 333 } 334 335 static void sctp_generate_t4_rto_event(struct timer_list *t) 336 { 337 struct sctp_association *asoc = 338 timer_container_of(asoc, t, timers[SCTP_EVENT_TIMEOUT_T4_RTO]); 339 340 sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_T4_RTO); 341 } 342 343 static void sctp_generate_t5_shutdown_guard_event(struct timer_list *t) 344 { 345 struct sctp_association *asoc = 346 timer_container_of(asoc, t, 347 timers[SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD]); 348 349 sctp_generate_timeout_event(asoc, 350 SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD); 351 352 } /* sctp_generate_t5_shutdown_guard_event() */ 353 354 static void sctp_generate_autoclose_event(struct timer_list *t) 355 { 356 struct sctp_association *asoc = 357 timer_container_of(asoc, t, 358 timers[SCTP_EVENT_TIMEOUT_AUTOCLOSE]); 359 360 sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_AUTOCLOSE); 361 } 362 363 /* Generate a heart beat event. If the sock is busy, reschedule. Make 364 * sure that the transport is still valid. 365 */ 366 void sctp_generate_heartbeat_event(struct timer_list *t) 367 { 368 struct sctp_transport *transport = timer_container_of(transport, t, 369 hb_timer); 370 struct sctp_association *asoc = transport->asoc; 371 struct sock *sk = asoc->base.sk; 372 struct net *net = sock_net(sk); 373 u32 elapsed, timeout; 374 int error = 0; 375 376 bh_lock_sock(sk); 377 if (sock_owned_by_user(sk)) { 378 pr_debug("%s: sock is busy\n", __func__); 379 380 /* Try again later. */ 381 if (!mod_timer(&transport->hb_timer, jiffies + (HZ/20))) 382 sctp_transport_hold(transport); 383 goto out_unlock; 384 } 385 386 /* Check if we should still send the heartbeat or reschedule */ 387 elapsed = jiffies - transport->last_time_sent; 388 timeout = sctp_transport_timeout(transport); 389 if (elapsed < timeout) { 390 elapsed = timeout - elapsed; 391 if (!mod_timer(&transport->hb_timer, jiffies + elapsed)) 392 sctp_transport_hold(transport); 393 goto out_unlock; 394 } 395 396 error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT, 397 SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_HEARTBEAT), 398 asoc->state, asoc->ep, asoc, 399 transport, GFP_ATOMIC); 400 401 if (error) 402 sk->sk_err = -error; 403 404 out_unlock: 405 bh_unlock_sock(sk); 406 sctp_transport_put(transport); 407 } 408 409 /* Handle the timeout of the ICMP protocol unreachable timer. Trigger 410 * the correct state machine transition that will close the association. 411 */ 412 void sctp_generate_proto_unreach_event(struct timer_list *t) 413 { 414 struct sctp_transport *transport = 415 timer_container_of(transport, t, proto_unreach_timer); 416 struct sctp_association *asoc = transport->asoc; 417 struct sock *sk = asoc->base.sk; 418 struct net *net = sock_net(sk); 419 420 bh_lock_sock(sk); 421 if (sock_owned_by_user(sk)) { 422 pr_debug("%s: sock is busy\n", __func__); 423 424 /* Try again later. */ 425 if (!mod_timer(&transport->proto_unreach_timer, 426 jiffies + (HZ/20))) 427 sctp_transport_hold(transport); 428 goto out_unlock; 429 } 430 431 /* Is this structure just waiting around for us to actually 432 * get destroyed? 433 */ 434 if (asoc->base.dead) 435 goto out_unlock; 436 437 sctp_do_sm(net, SCTP_EVENT_T_OTHER, 438 SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH), 439 asoc->state, asoc->ep, asoc, transport, GFP_ATOMIC); 440 441 out_unlock: 442 bh_unlock_sock(sk); 443 sctp_transport_put(transport); 444 } 445 446 /* Handle the timeout of the RE-CONFIG timer. */ 447 void sctp_generate_reconf_event(struct timer_list *t) 448 { 449 struct sctp_transport *transport = 450 timer_container_of(transport, t, reconf_timer); 451 struct sctp_association *asoc = transport->asoc; 452 struct sock *sk = asoc->base.sk; 453 struct net *net = sock_net(sk); 454 int error = 0; 455 456 bh_lock_sock(sk); 457 if (sock_owned_by_user(sk)) { 458 pr_debug("%s: sock is busy\n", __func__); 459 460 /* Try again later. */ 461 if (!mod_timer(&transport->reconf_timer, jiffies + (HZ / 20))) 462 sctp_transport_hold(transport); 463 goto out_unlock; 464 } 465 466 /* This happens when the response arrives after the timer is triggered. */ 467 if (!asoc->strreset_chunk) 468 goto out_unlock; 469 470 error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT, 471 SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_RECONF), 472 asoc->state, asoc->ep, asoc, 473 transport, GFP_ATOMIC); 474 475 if (error) 476 sk->sk_err = -error; 477 478 out_unlock: 479 bh_unlock_sock(sk); 480 sctp_transport_put(transport); 481 } 482 483 /* Handle the timeout of the probe timer. */ 484 void sctp_generate_probe_event(struct timer_list *t) 485 { 486 struct sctp_transport *transport = timer_container_of(transport, t, 487 probe_timer); 488 struct sctp_association *asoc = transport->asoc; 489 struct sock *sk = asoc->base.sk; 490 struct net *net = sock_net(sk); 491 int error = 0; 492 493 bh_lock_sock(sk); 494 if (sock_owned_by_user(sk)) { 495 pr_debug("%s: sock is busy\n", __func__); 496 497 /* Try again later. */ 498 if (!mod_timer(&transport->probe_timer, jiffies + (HZ / 20))) 499 sctp_transport_hold(transport); 500 goto out_unlock; 501 } 502 503 error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT, 504 SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_PROBE), 505 asoc->state, asoc->ep, asoc, 506 transport, GFP_ATOMIC); 507 508 if (error) 509 sk->sk_err = -error; 510 511 out_unlock: 512 bh_unlock_sock(sk); 513 sctp_transport_put(transport); 514 } 515 516 /* Inject a SACK Timeout event into the state machine. */ 517 static void sctp_generate_sack_event(struct timer_list *t) 518 { 519 struct sctp_association *asoc = 520 timer_container_of(asoc, t, timers[SCTP_EVENT_TIMEOUT_SACK]); 521 522 sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_SACK); 523 } 524 525 sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = { 526 [SCTP_EVENT_TIMEOUT_NONE] = NULL, 527 [SCTP_EVENT_TIMEOUT_T1_COOKIE] = sctp_generate_t1_cookie_event, 528 [SCTP_EVENT_TIMEOUT_T1_INIT] = sctp_generate_t1_init_event, 529 [SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = sctp_generate_t2_shutdown_event, 530 [SCTP_EVENT_TIMEOUT_T3_RTX] = NULL, 531 [SCTP_EVENT_TIMEOUT_T4_RTO] = sctp_generate_t4_rto_event, 532 [SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD] = 533 sctp_generate_t5_shutdown_guard_event, 534 [SCTP_EVENT_TIMEOUT_HEARTBEAT] = NULL, 535 [SCTP_EVENT_TIMEOUT_RECONF] = NULL, 536 [SCTP_EVENT_TIMEOUT_SACK] = sctp_generate_sack_event, 537 [SCTP_EVENT_TIMEOUT_AUTOCLOSE] = sctp_generate_autoclose_event, 538 }; 539 540 541 /* RFC 2960 8.2 Path Failure Detection 542 * 543 * When its peer endpoint is multi-homed, an endpoint should keep a 544 * error counter for each of the destination transport addresses of the 545 * peer endpoint. 546 * 547 * Each time the T3-rtx timer expires on any address, or when a 548 * HEARTBEAT sent to an idle address is not acknowledged within a RTO, 549 * the error counter of that destination address will be incremented. 550 * When the value in the error counter exceeds the protocol parameter 551 * 'Path.Max.Retrans' of that destination address, the endpoint should 552 * mark the destination transport address as inactive, and a 553 * notification SHOULD be sent to the upper layer. 554 * 555 */ 556 static void sctp_do_8_2_transport_strike(struct sctp_cmd_seq *commands, 557 struct sctp_association *asoc, 558 struct sctp_transport *transport, 559 int is_hb) 560 { 561 /* The check for association's overall error counter exceeding the 562 * threshold is done in the state function. 563 */ 564 /* We are here due to a timer expiration. If the timer was 565 * not a HEARTBEAT, then normal error tracking is done. 566 * If the timer was a heartbeat, we only increment error counts 567 * when we already have an outstanding HEARTBEAT that has not 568 * been acknowledged. 569 * Additionally, some tranport states inhibit error increments. 570 */ 571 if (!is_hb) { 572 asoc->overall_error_count++; 573 if (transport->state != SCTP_INACTIVE) 574 transport->error_count++; 575 } else if (transport->hb_sent) { 576 if (transport->state != SCTP_UNCONFIRMED) 577 asoc->overall_error_count++; 578 if (transport->state != SCTP_INACTIVE) 579 transport->error_count++; 580 } 581 582 /* If the transport error count is greater than the pf_retrans 583 * threshold, and less than pathmaxrtx, and if the current state 584 * is SCTP_ACTIVE, then mark this transport as Partially Failed, 585 * see SCTP Quick Failover Draft, section 5.1 586 */ 587 if (asoc->base.net->sctp.pf_enable && 588 transport->state == SCTP_ACTIVE && 589 transport->error_count < transport->pathmaxrxt && 590 transport->error_count > transport->pf_retrans) { 591 592 sctp_assoc_control_transport(asoc, transport, 593 SCTP_TRANSPORT_PF, 594 0); 595 596 /* Update the hb timer to resend a heartbeat every rto */ 597 sctp_transport_reset_hb_timer(transport); 598 } 599 600 if (transport->state != SCTP_INACTIVE && 601 (transport->error_count > transport->pathmaxrxt)) { 602 pr_debug("%s: association:%p transport addr:%pISpc failed\n", 603 __func__, asoc, &transport->ipaddr.sa); 604 605 sctp_assoc_control_transport(asoc, transport, 606 SCTP_TRANSPORT_DOWN, 607 SCTP_FAILED_THRESHOLD); 608 } 609 610 if (transport->error_count > transport->ps_retrans && 611 asoc->peer.primary_path == transport && 612 asoc->peer.active_path != transport) 613 sctp_assoc_set_primary(asoc, asoc->peer.active_path); 614 615 /* E2) For the destination address for which the timer 616 * expires, set RTO <- RTO * 2 ("back off the timer"). The 617 * maximum value discussed in rule C7 above (RTO.max) may be 618 * used to provide an upper bound to this doubling operation. 619 * 620 * Special Case: the first HB doesn't trigger exponential backoff. 621 * The first unacknowledged HB triggers it. We do this with a flag 622 * that indicates that we have an outstanding HB. 623 */ 624 if (!is_hb || transport->hb_sent) { 625 transport->rto = min((transport->rto * 2), transport->asoc->rto_max); 626 sctp_max_rto(asoc, transport); 627 } 628 } 629 630 /* Worker routine to handle INIT command failure. */ 631 static void sctp_cmd_init_failed(struct sctp_cmd_seq *commands, 632 struct sctp_association *asoc, 633 unsigned int error) 634 { 635 struct sctp_ulpevent *event; 636 637 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_CANT_STR_ASSOC, 638 (__u16)error, 0, 0, NULL, 639 GFP_ATOMIC); 640 641 if (event) 642 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 643 SCTP_ULPEVENT(event)); 644 645 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 646 SCTP_STATE(SCTP_STATE_CLOSED)); 647 648 /* SEND_FAILED sent later when cleaning up the association. */ 649 asoc->outqueue.error = error; 650 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 651 } 652 653 /* Worker routine to handle SCTP_CMD_ASSOC_FAILED. */ 654 static void sctp_cmd_assoc_failed(struct sctp_cmd_seq *commands, 655 struct sctp_association *asoc, 656 enum sctp_event_type event_type, 657 union sctp_subtype subtype, 658 struct sctp_chunk *chunk, 659 unsigned int error) 660 { 661 struct sctp_ulpevent *event; 662 struct sctp_chunk *abort; 663 664 /* Cancel any partial delivery in progress. */ 665 asoc->stream.si->abort_pd(&asoc->ulpq, GFP_ATOMIC); 666 667 if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT) 668 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST, 669 (__u16)error, 0, 0, chunk, 670 GFP_ATOMIC); 671 else 672 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST, 673 (__u16)error, 0, 0, NULL, 674 GFP_ATOMIC); 675 if (event) 676 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 677 SCTP_ULPEVENT(event)); 678 679 if (asoc->overall_error_count >= asoc->max_retrans) { 680 abort = sctp_make_violation_max_retrans(asoc, chunk); 681 if (abort) 682 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 683 SCTP_CHUNK(abort)); 684 } 685 686 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 687 SCTP_STATE(SCTP_STATE_CLOSED)); 688 689 /* SEND_FAILED sent later when cleaning up the association. */ 690 asoc->outqueue.error = error; 691 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 692 } 693 694 /* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT 695 * inside the cookie. In reality, this is only used for INIT-ACK processing 696 * since all other cases use "temporary" associations and can do all 697 * their work in statefuns directly. 698 */ 699 static int sctp_cmd_process_init(struct sctp_cmd_seq *commands, 700 struct sctp_association *asoc, 701 struct sctp_chunk *chunk, 702 struct sctp_init_chunk *peer_init, 703 gfp_t gfp) 704 { 705 int error; 706 707 /* We only process the init as a sideeffect in a single 708 * case. This is when we process the INIT-ACK. If we 709 * fail during INIT processing (due to malloc problems), 710 * just return the error and stop processing the stack. 711 */ 712 if (!sctp_process_init(asoc, chunk, sctp_source(chunk), peer_init, gfp)) 713 error = -ENOMEM; 714 else 715 error = 0; 716 717 return error; 718 } 719 720 /* Helper function to break out starting up of heartbeat timers. */ 721 static void sctp_cmd_hb_timers_start(struct sctp_cmd_seq *cmds, 722 struct sctp_association *asoc) 723 { 724 struct sctp_transport *t; 725 726 /* Start a heartbeat timer for each transport on the association. 727 * hold a reference on the transport to make sure none of 728 * the needed data structures go away. 729 */ 730 list_for_each_entry(t, &asoc->peer.transport_addr_list, transports) 731 sctp_transport_reset_hb_timer(t); 732 } 733 734 static void sctp_cmd_hb_timers_stop(struct sctp_cmd_seq *cmds, 735 struct sctp_association *asoc) 736 { 737 struct sctp_transport *t; 738 739 /* Stop all heartbeat timers. */ 740 741 list_for_each_entry(t, &asoc->peer.transport_addr_list, 742 transports) { 743 if (timer_delete(&t->hb_timer)) 744 sctp_transport_put(t); 745 } 746 } 747 748 /* Helper function to stop any pending T3-RTX timers */ 749 static void sctp_cmd_t3_rtx_timers_stop(struct sctp_cmd_seq *cmds, 750 struct sctp_association *asoc) 751 { 752 struct sctp_transport *t; 753 754 list_for_each_entry(t, &asoc->peer.transport_addr_list, 755 transports) { 756 if (timer_delete(&t->T3_rtx_timer)) 757 sctp_transport_put(t); 758 } 759 } 760 761 762 /* Helper function to handle the reception of an HEARTBEAT ACK. */ 763 static void sctp_cmd_transport_on(struct sctp_cmd_seq *cmds, 764 struct sctp_association *asoc, 765 struct sctp_transport *t, 766 struct sctp_chunk *chunk) 767 { 768 struct sctp_sender_hb_info *hbinfo; 769 int was_unconfirmed = 0; 770 771 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the 772 * HEARTBEAT should clear the error counter of the destination 773 * transport address to which the HEARTBEAT was sent. 774 */ 775 t->error_count = 0; 776 777 /* 778 * Although RFC4960 specifies that the overall error count must 779 * be cleared when a HEARTBEAT ACK is received, we make an 780 * exception while in SHUTDOWN PENDING. If the peer keeps its 781 * window shut forever, we may never be able to transmit our 782 * outstanding data and rely on the retransmission limit be reached 783 * to shutdown the association. 784 */ 785 if (t->asoc->state < SCTP_STATE_SHUTDOWN_PENDING) 786 t->asoc->overall_error_count = 0; 787 788 /* Clear the hb_sent flag to signal that we had a good 789 * acknowledgement. 790 */ 791 t->hb_sent = 0; 792 793 /* Mark the destination transport address as active if it is not so 794 * marked. 795 */ 796 if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED)) { 797 was_unconfirmed = 1; 798 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP, 799 SCTP_HEARTBEAT_SUCCESS); 800 } 801 802 if (t->state == SCTP_PF) 803 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP, 804 SCTP_HEARTBEAT_SUCCESS); 805 806 /* HB-ACK was received for a the proper HB. Consider this 807 * forward progress. 808 */ 809 if (t->dst) 810 sctp_transport_dst_confirm(t); 811 812 /* The receiver of the HEARTBEAT ACK should also perform an 813 * RTT measurement for that destination transport address 814 * using the time value carried in the HEARTBEAT ACK chunk. 815 * If the transport's rto_pending variable has been cleared, 816 * it was most likely due to a retransmit. However, we want 817 * to re-enable it to properly update the rto. 818 */ 819 if (t->rto_pending == 0) 820 t->rto_pending = 1; 821 822 hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data; 823 sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at)); 824 825 /* Update the heartbeat timer. */ 826 sctp_transport_reset_hb_timer(t); 827 828 if (was_unconfirmed && asoc->peer.transport_count == 1) 829 sctp_transport_immediate_rtx(t); 830 } 831 832 833 /* Helper function to process the process SACK command. */ 834 static int sctp_cmd_process_sack(struct sctp_cmd_seq *cmds, 835 struct sctp_association *asoc, 836 struct sctp_chunk *chunk) 837 { 838 int err = 0; 839 840 if (sctp_outq_sack(&asoc->outqueue, chunk)) { 841 /* There are no more TSNs awaiting SACK. */ 842 err = sctp_do_sm(asoc->base.net, SCTP_EVENT_T_OTHER, 843 SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN), 844 asoc->state, asoc->ep, asoc, NULL, 845 GFP_ATOMIC); 846 } 847 848 return err; 849 } 850 851 /* Helper function to set the timeout value for T2-SHUTDOWN timer and to set 852 * the transport for a shutdown chunk. 853 */ 854 static void sctp_cmd_setup_t2(struct sctp_cmd_seq *cmds, 855 struct sctp_association *asoc, 856 struct sctp_chunk *chunk) 857 { 858 struct sctp_transport *t; 859 860 if (chunk->transport) 861 t = chunk->transport; 862 else { 863 t = sctp_assoc_choose_alter_transport(asoc, 864 asoc->shutdown_last_sent_to); 865 chunk->transport = t; 866 } 867 asoc->shutdown_last_sent_to = t; 868 asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto; 869 } 870 871 /* Helper function to change the state of an association. */ 872 static void sctp_cmd_new_state(struct sctp_cmd_seq *cmds, 873 struct sctp_association *asoc, 874 enum sctp_state state) 875 { 876 struct sock *sk = asoc->base.sk; 877 878 asoc->state = state; 879 880 pr_debug("%s: asoc:%p[%s]\n", __func__, asoc, sctp_state_tbl[state]); 881 882 if (sctp_style(sk, TCP)) { 883 /* Change the sk->sk_state of a TCP-style socket that has 884 * successfully completed a connect() call. 885 */ 886 if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED)) 887 inet_sk_set_state(sk, SCTP_SS_ESTABLISHED); 888 889 /* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */ 890 if (sctp_state(asoc, SHUTDOWN_RECEIVED) && 891 sctp_sstate(sk, ESTABLISHED)) { 892 inet_sk_set_state(sk, SCTP_SS_CLOSING); 893 sk->sk_shutdown |= RCV_SHUTDOWN; 894 } 895 } 896 897 if (sctp_state(asoc, COOKIE_WAIT)) { 898 /* Reset init timeouts since they may have been 899 * increased due to timer expirations. 900 */ 901 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] = 902 asoc->rto_initial; 903 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] = 904 asoc->rto_initial; 905 } 906 907 if (sctp_state(asoc, ESTABLISHED)) { 908 kfree(asoc->peer.cookie); 909 asoc->peer.cookie = NULL; 910 } 911 912 if (sctp_state(asoc, ESTABLISHED) || 913 sctp_state(asoc, CLOSED) || 914 sctp_state(asoc, SHUTDOWN_RECEIVED)) { 915 /* Wake up any processes waiting in the asoc's wait queue in 916 * sctp_wait_for_connect() or sctp_wait_for_sndbuf(). 917 */ 918 if (waitqueue_active(&asoc->wait)) 919 wake_up_interruptible(&asoc->wait); 920 921 /* Wake up any processes waiting in the sk's sleep queue of 922 * a TCP-style or UDP-style peeled-off socket in 923 * sctp_wait_for_accept() or sctp_wait_for_packet(). 924 * For a UDP-style socket, the waiters are woken up by the 925 * notifications. 926 */ 927 if (!sctp_style(sk, UDP)) 928 sk->sk_state_change(sk); 929 } 930 931 if (sctp_state(asoc, SHUTDOWN_PENDING) && 932 !sctp_outq_is_empty(&asoc->outqueue)) 933 sctp_outq_uncork(&asoc->outqueue, GFP_ATOMIC); 934 } 935 936 /* Helper function to delete an association. */ 937 static void sctp_cmd_delete_tcb(struct sctp_cmd_seq *cmds, 938 struct sctp_association *asoc) 939 { 940 struct sock *sk = asoc->base.sk; 941 942 /* If it is a non-temporary association belonging to a TCP-style 943 * listening socket that is not closed, do not free it so that accept() 944 * can pick it up later. 945 */ 946 if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) && 947 (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK)) 948 return; 949 950 sctp_association_free(asoc); 951 } 952 953 /* 954 * ADDIP Section 4.1 ASCONF Chunk Procedures 955 * A4) Start a T-4 RTO timer, using the RTO value of the selected 956 * destination address (we use active path instead of primary path just 957 * because primary path may be inactive. 958 */ 959 static void sctp_cmd_setup_t4(struct sctp_cmd_seq *cmds, 960 struct sctp_association *asoc, 961 struct sctp_chunk *chunk) 962 { 963 struct sctp_transport *t; 964 965 t = sctp_assoc_choose_alter_transport(asoc, chunk->transport); 966 asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto; 967 chunk->transport = t; 968 } 969 970 /* Process an incoming Operation Error Chunk. */ 971 static void sctp_cmd_process_operr(struct sctp_cmd_seq *cmds, 972 struct sctp_association *asoc, 973 struct sctp_chunk *chunk) 974 { 975 struct sctp_errhdr *err_hdr; 976 struct sctp_ulpevent *ev; 977 978 while (chunk->chunk_end > chunk->skb->data) { 979 err_hdr = (struct sctp_errhdr *)(chunk->skb->data); 980 981 ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0, 982 GFP_ATOMIC); 983 if (!ev) 984 return; 985 986 asoc->stream.si->enqueue_event(&asoc->ulpq, ev); 987 988 switch (err_hdr->cause) { 989 case SCTP_ERROR_UNKNOWN_CHUNK: 990 { 991 struct sctp_chunkhdr *unk_chunk_hdr; 992 993 unk_chunk_hdr = (struct sctp_chunkhdr *)(err_hdr + 1); 994 switch (unk_chunk_hdr->type) { 995 /* ADDIP 4.1 A9) If the peer responds to an ASCONF with 996 * an ERROR chunk reporting that it did not recognized 997 * the ASCONF chunk type, the sender of the ASCONF MUST 998 * NOT send any further ASCONF chunks and MUST stop its 999 * T-4 timer. 1000 */ 1001 case SCTP_CID_ASCONF: 1002 if (asoc->peer.asconf_capable == 0) 1003 break; 1004 1005 asoc->peer.asconf_capable = 0; 1006 sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP, 1007 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 1008 break; 1009 default: 1010 break; 1011 } 1012 break; 1013 } 1014 default: 1015 break; 1016 } 1017 } 1018 } 1019 1020 /* Helper function to remove the association non-primary peer 1021 * transports. 1022 */ 1023 static void sctp_cmd_del_non_primary(struct sctp_association *asoc) 1024 { 1025 struct sctp_transport *t; 1026 struct list_head *temp; 1027 struct list_head *pos; 1028 1029 list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) { 1030 t = list_entry(pos, struct sctp_transport, transports); 1031 if (!sctp_cmp_addr_exact(&t->ipaddr, 1032 &asoc->peer.primary_addr)) { 1033 sctp_assoc_rm_peer(asoc, t); 1034 } 1035 } 1036 } 1037 1038 /* Helper function to set sk_err on a 1-1 style socket. */ 1039 static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error) 1040 { 1041 struct sock *sk = asoc->base.sk; 1042 1043 if (!sctp_style(sk, UDP)) 1044 sk->sk_err = error; 1045 } 1046 1047 /* Helper function to generate an association change event */ 1048 static void sctp_cmd_assoc_change(struct sctp_cmd_seq *commands, 1049 struct sctp_association *asoc, 1050 u8 state) 1051 { 1052 struct sctp_ulpevent *ev; 1053 1054 ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0, 1055 asoc->c.sinit_num_ostreams, 1056 asoc->c.sinit_max_instreams, 1057 NULL, GFP_ATOMIC); 1058 if (ev) 1059 asoc->stream.si->enqueue_event(&asoc->ulpq, ev); 1060 } 1061 1062 static void sctp_cmd_peer_no_auth(struct sctp_cmd_seq *commands, 1063 struct sctp_association *asoc) 1064 { 1065 struct sctp_ulpevent *ev; 1066 1067 ev = sctp_ulpevent_make_authkey(asoc, 0, SCTP_AUTH_NO_AUTH, GFP_ATOMIC); 1068 if (ev) 1069 asoc->stream.si->enqueue_event(&asoc->ulpq, ev); 1070 } 1071 1072 /* Helper function to generate an adaptation indication event */ 1073 static void sctp_cmd_adaptation_ind(struct sctp_cmd_seq *commands, 1074 struct sctp_association *asoc) 1075 { 1076 struct sctp_ulpevent *ev; 1077 1078 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC); 1079 1080 if (ev) 1081 asoc->stream.si->enqueue_event(&asoc->ulpq, ev); 1082 } 1083 1084 1085 static void sctp_cmd_t1_timer_update(struct sctp_association *asoc, 1086 enum sctp_event_timeout timer, 1087 char *name) 1088 { 1089 struct sctp_transport *t; 1090 1091 t = asoc->init_last_sent_to; 1092 asoc->init_err_counter++; 1093 1094 if (t->init_sent_count > (asoc->init_cycle + 1)) { 1095 asoc->timeouts[timer] *= 2; 1096 if (asoc->timeouts[timer] > asoc->max_init_timeo) { 1097 asoc->timeouts[timer] = asoc->max_init_timeo; 1098 } 1099 asoc->init_cycle++; 1100 1101 pr_debug("%s: T1[%s] timeout adjustment init_err_counter:%d" 1102 " cycle:%d timeout:%ld\n", __func__, name, 1103 asoc->init_err_counter, asoc->init_cycle, 1104 asoc->timeouts[timer]); 1105 } 1106 1107 } 1108 1109 /* Send the whole message, chunk by chunk, to the outqueue. 1110 * This way the whole message is queued up and bundling if 1111 * encouraged for small fragments. 1112 */ 1113 static void sctp_cmd_send_msg(struct sctp_association *asoc, 1114 struct sctp_datamsg *msg, gfp_t gfp) 1115 { 1116 struct sctp_chunk *chunk; 1117 1118 list_for_each_entry(chunk, &msg->chunks, frag_list) 1119 sctp_outq_tail(&asoc->outqueue, chunk, gfp); 1120 1121 asoc->outqueue.sched->enqueue(&asoc->outqueue, msg); 1122 } 1123 1124 1125 /* These three macros allow us to pull the debugging code out of the 1126 * main flow of sctp_do_sm() to keep attention focused on the real 1127 * functionality there. 1128 */ 1129 #define debug_pre_sfn() \ 1130 pr_debug("%s[pre-fn]: ep:%p, %s, %s, asoc:%p[%s], %s\n", __func__, \ 1131 ep, sctp_evttype_tbl[event_type], (*debug_fn)(subtype), \ 1132 asoc, sctp_state_tbl[state], state_fn->name) 1133 1134 #define debug_post_sfn() \ 1135 pr_debug("%s[post-fn]: asoc:%p, status:%s\n", __func__, asoc, \ 1136 sctp_status_tbl[status]) 1137 1138 #define debug_post_sfx() \ 1139 pr_debug("%s[post-sfx]: error:%d, asoc:%p[%s]\n", __func__, error, \ 1140 asoc, sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \ 1141 sctp_assoc2id(asoc))) ? asoc->state : SCTP_STATE_CLOSED]) 1142 1143 /* 1144 * This is the master state machine processing function. 1145 * 1146 * If you want to understand all of lksctp, this is a 1147 * good place to start. 1148 */ 1149 int sctp_do_sm(struct net *net, enum sctp_event_type event_type, 1150 union sctp_subtype subtype, enum sctp_state state, 1151 struct sctp_endpoint *ep, struct sctp_association *asoc, 1152 void *event_arg, gfp_t gfp) 1153 { 1154 typedef const char *(printfn_t)(union sctp_subtype); 1155 static printfn_t *table[] = { 1156 NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname, 1157 }; 1158 printfn_t *debug_fn __attribute__ ((unused)) = table[event_type]; 1159 const struct sctp_sm_table_entry *state_fn; 1160 struct sctp_cmd_seq commands; 1161 enum sctp_disposition status; 1162 int error = 0; 1163 1164 /* Look up the state function, run it, and then process the 1165 * side effects. These three steps are the heart of lksctp. 1166 */ 1167 state_fn = sctp_sm_lookup_event(net, event_type, state, subtype); 1168 1169 sctp_init_cmd_seq(&commands); 1170 1171 debug_pre_sfn(); 1172 status = state_fn->fn(net, ep, asoc, subtype, event_arg, &commands); 1173 debug_post_sfn(); 1174 1175 error = sctp_side_effects(event_type, subtype, state, 1176 ep, &asoc, event_arg, status, 1177 &commands, gfp); 1178 debug_post_sfx(); 1179 1180 return error; 1181 } 1182 1183 /***************************************************************** 1184 * This the master state function side effect processing function. 1185 *****************************************************************/ 1186 static int sctp_side_effects(enum sctp_event_type event_type, 1187 union sctp_subtype subtype, 1188 enum sctp_state state, 1189 struct sctp_endpoint *ep, 1190 struct sctp_association **asoc, 1191 void *event_arg, 1192 enum sctp_disposition status, 1193 struct sctp_cmd_seq *commands, 1194 gfp_t gfp) 1195 { 1196 int error; 1197 1198 /* FIXME - Most of the dispositions left today would be categorized 1199 * as "exceptional" dispositions. For those dispositions, it 1200 * may not be proper to run through any of the commands at all. 1201 * For example, the command interpreter might be run only with 1202 * disposition SCTP_DISPOSITION_CONSUME. 1203 */ 1204 if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state, 1205 ep, *asoc, 1206 event_arg, status, 1207 commands, gfp))) 1208 goto bail; 1209 1210 switch (status) { 1211 case SCTP_DISPOSITION_DISCARD: 1212 pr_debug("%s: ignored sctp protocol event - state:%d, " 1213 "event_type:%d, event_id:%d\n", __func__, state, 1214 event_type, subtype.chunk); 1215 break; 1216 1217 case SCTP_DISPOSITION_NOMEM: 1218 /* We ran out of memory, so we need to discard this 1219 * packet. 1220 */ 1221 /* BUG--we should now recover some memory, probably by 1222 * reneging... 1223 */ 1224 error = -ENOMEM; 1225 break; 1226 1227 case SCTP_DISPOSITION_DELETE_TCB: 1228 case SCTP_DISPOSITION_ABORT: 1229 /* This should now be a command. */ 1230 *asoc = NULL; 1231 break; 1232 1233 case SCTP_DISPOSITION_CONSUME: 1234 /* 1235 * We should no longer have much work to do here as the 1236 * real work has been done as explicit commands above. 1237 */ 1238 break; 1239 1240 case SCTP_DISPOSITION_VIOLATION: 1241 net_err_ratelimited("protocol violation state %d chunkid %d\n", 1242 state, subtype.chunk); 1243 break; 1244 1245 case SCTP_DISPOSITION_NOT_IMPL: 1246 pr_warn("unimplemented feature in state %d, event_type %d, event_id %d\n", 1247 state, event_type, subtype.chunk); 1248 break; 1249 1250 case SCTP_DISPOSITION_BUG: 1251 pr_err("bug in state %d, event_type %d, event_id %d\n", 1252 state, event_type, subtype.chunk); 1253 BUG(); 1254 break; 1255 1256 default: 1257 pr_err("impossible disposition %d in state %d, event_type %d, event_id %d\n", 1258 status, state, event_type, subtype.chunk); 1259 error = status; 1260 if (error >= 0) 1261 error = -EINVAL; 1262 WARN_ON_ONCE(1); 1263 break; 1264 } 1265 1266 bail: 1267 return error; 1268 } 1269 1270 /******************************************************************** 1271 * 2nd Level Abstractions 1272 ********************************************************************/ 1273 1274 /* This is the side-effect interpreter. */ 1275 static int sctp_cmd_interpreter(enum sctp_event_type event_type, 1276 union sctp_subtype subtype, 1277 enum sctp_state state, 1278 struct sctp_endpoint *ep, 1279 struct sctp_association *asoc, 1280 void *event_arg, 1281 enum sctp_disposition status, 1282 struct sctp_cmd_seq *commands, 1283 gfp_t gfp) 1284 { 1285 struct sctp_sock *sp = sctp_sk(ep->base.sk); 1286 struct sctp_chunk *chunk = NULL, *new_obj; 1287 struct sctp_packet *packet; 1288 struct sctp_sackhdr sackh; 1289 struct timer_list *timer; 1290 struct sctp_transport *t; 1291 unsigned long timeout; 1292 struct sctp_cmd *cmd; 1293 int local_cork = 0; 1294 int error = 0; 1295 int force; 1296 1297 if (SCTP_EVENT_T_TIMEOUT != event_type) 1298 chunk = event_arg; 1299 1300 /* Note: This whole file is a huge candidate for rework. 1301 * For example, each command could either have its own handler, so 1302 * the loop would look like: 1303 * while (cmds) 1304 * cmd->handle(x, y, z) 1305 * --jgrimm 1306 */ 1307 while (NULL != (cmd = sctp_next_cmd(commands))) { 1308 switch (cmd->verb) { 1309 case SCTP_CMD_NOP: 1310 /* Do nothing. */ 1311 break; 1312 1313 case SCTP_CMD_NEW_ASOC: 1314 /* Register a new association. */ 1315 if (local_cork) { 1316 sctp_outq_uncork(&asoc->outqueue, gfp); 1317 local_cork = 0; 1318 } 1319 1320 /* Register with the endpoint. */ 1321 asoc = cmd->obj.asoc; 1322 BUG_ON(asoc->peer.primary_path == NULL); 1323 sctp_endpoint_add_asoc(ep, asoc); 1324 break; 1325 1326 case SCTP_CMD_PURGE_OUTQUEUE: 1327 sctp_outq_teardown(&asoc->outqueue); 1328 break; 1329 1330 case SCTP_CMD_DELETE_TCB: 1331 if (local_cork) { 1332 sctp_outq_uncork(&asoc->outqueue, gfp); 1333 local_cork = 0; 1334 } 1335 /* Delete the current association. */ 1336 sctp_cmd_delete_tcb(commands, asoc); 1337 asoc = NULL; 1338 break; 1339 1340 case SCTP_CMD_NEW_STATE: 1341 /* Enter a new state. */ 1342 sctp_cmd_new_state(commands, asoc, cmd->obj.state); 1343 break; 1344 1345 case SCTP_CMD_REPORT_TSN: 1346 /* Record the arrival of a TSN. */ 1347 error = sctp_tsnmap_mark(&asoc->peer.tsn_map, 1348 cmd->obj.u32, NULL); 1349 break; 1350 1351 case SCTP_CMD_REPORT_FWDTSN: 1352 asoc->stream.si->report_ftsn(&asoc->ulpq, cmd->obj.u32); 1353 break; 1354 1355 case SCTP_CMD_PROCESS_FWDTSN: 1356 asoc->stream.si->handle_ftsn(&asoc->ulpq, 1357 cmd->obj.chunk); 1358 break; 1359 1360 case SCTP_CMD_GEN_SACK: 1361 /* Generate a Selective ACK. 1362 * The argument tells us whether to just count 1363 * the packet and MAYBE generate a SACK, or 1364 * force a SACK out. 1365 */ 1366 force = cmd->obj.i32; 1367 error = sctp_gen_sack(asoc, force, commands); 1368 break; 1369 1370 case SCTP_CMD_PROCESS_SACK: 1371 /* Process an inbound SACK. */ 1372 error = sctp_cmd_process_sack(commands, asoc, 1373 cmd->obj.chunk); 1374 break; 1375 1376 case SCTP_CMD_GEN_INIT_ACK: 1377 /* Generate an INIT ACK chunk. */ 1378 new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC, 1379 0); 1380 if (!new_obj) { 1381 error = -ENOMEM; 1382 break; 1383 } 1384 1385 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1386 SCTP_CHUNK(new_obj)); 1387 break; 1388 1389 case SCTP_CMD_PEER_INIT: 1390 /* Process a unified INIT from the peer. 1391 * Note: Only used during INIT-ACK processing. If 1392 * there is an error just return to the outter 1393 * layer which will bail. 1394 */ 1395 error = sctp_cmd_process_init(commands, asoc, chunk, 1396 cmd->obj.init, gfp); 1397 break; 1398 1399 case SCTP_CMD_GEN_COOKIE_ECHO: 1400 /* Generate a COOKIE ECHO chunk. */ 1401 new_obj = sctp_make_cookie_echo(asoc, chunk); 1402 if (!new_obj) { 1403 if (cmd->obj.chunk) 1404 sctp_chunk_free(cmd->obj.chunk); 1405 error = -ENOMEM; 1406 break; 1407 } 1408 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1409 SCTP_CHUNK(new_obj)); 1410 1411 /* If there is an ERROR chunk to be sent along with 1412 * the COOKIE_ECHO, send it, too. 1413 */ 1414 if (cmd->obj.chunk) 1415 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1416 SCTP_CHUNK(cmd->obj.chunk)); 1417 1418 if (new_obj->transport) { 1419 new_obj->transport->init_sent_count++; 1420 asoc->init_last_sent_to = new_obj->transport; 1421 } 1422 1423 /* FIXME - Eventually come up with a cleaner way to 1424 * enabling COOKIE-ECHO + DATA bundling during 1425 * multihoming stale cookie scenarios, the following 1426 * command plays with asoc->peer.retran_path to 1427 * avoid the problem of sending the COOKIE-ECHO and 1428 * DATA in different paths, which could result 1429 * in the association being ABORTed if the DATA chunk 1430 * is processed first by the server. Checking the 1431 * init error counter simply causes this command 1432 * to be executed only during failed attempts of 1433 * association establishment. 1434 */ 1435 if ((asoc->peer.retran_path != 1436 asoc->peer.primary_path) && 1437 (asoc->init_err_counter > 0)) { 1438 sctp_add_cmd_sf(commands, 1439 SCTP_CMD_FORCE_PRIM_RETRAN, 1440 SCTP_NULL()); 1441 } 1442 1443 break; 1444 1445 case SCTP_CMD_GEN_SHUTDOWN: 1446 /* Generate SHUTDOWN when in SHUTDOWN_SENT state. 1447 * Reset error counts. 1448 */ 1449 asoc->overall_error_count = 0; 1450 1451 /* Generate a SHUTDOWN chunk. */ 1452 new_obj = sctp_make_shutdown(asoc, chunk); 1453 if (!new_obj) { 1454 error = -ENOMEM; 1455 break; 1456 } 1457 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1458 SCTP_CHUNK(new_obj)); 1459 break; 1460 1461 case SCTP_CMD_CHUNK_ULP: 1462 /* Send a chunk to the sockets layer. */ 1463 pr_debug("%s: sm_sideff: chunk_up:%p, ulpq:%p\n", 1464 __func__, cmd->obj.chunk, &asoc->ulpq); 1465 1466 asoc->stream.si->ulpevent_data(&asoc->ulpq, 1467 cmd->obj.chunk, 1468 GFP_ATOMIC); 1469 break; 1470 1471 case SCTP_CMD_EVENT_ULP: 1472 /* Send a notification to the sockets layer. */ 1473 pr_debug("%s: sm_sideff: event_up:%p, ulpq:%p\n", 1474 __func__, cmd->obj.ulpevent, &asoc->ulpq); 1475 1476 asoc->stream.si->enqueue_event(&asoc->ulpq, 1477 cmd->obj.ulpevent); 1478 break; 1479 1480 case SCTP_CMD_REPLY: 1481 /* If an caller has not already corked, do cork. */ 1482 if (!asoc->outqueue.cork) { 1483 sctp_outq_cork(&asoc->outqueue); 1484 local_cork = 1; 1485 } 1486 /* Send a chunk to our peer. */ 1487 sctp_outq_tail(&asoc->outqueue, cmd->obj.chunk, gfp); 1488 break; 1489 1490 case SCTP_CMD_SEND_PKT: 1491 /* Send a full packet to our peer. */ 1492 packet = cmd->obj.packet; 1493 sctp_packet_transmit(packet, gfp); 1494 sctp_ootb_pkt_free(packet); 1495 break; 1496 1497 case SCTP_CMD_T1_RETRAN: 1498 /* Mark a transport for retransmission. */ 1499 sctp_retransmit(&asoc->outqueue, cmd->obj.transport, 1500 SCTP_RTXR_T1_RTX); 1501 break; 1502 1503 case SCTP_CMD_RETRAN: 1504 /* Mark a transport for retransmission. */ 1505 sctp_retransmit(&asoc->outqueue, cmd->obj.transport, 1506 SCTP_RTXR_T3_RTX); 1507 break; 1508 1509 case SCTP_CMD_ECN_CE: 1510 /* Do delayed CE processing. */ 1511 sctp_do_ecn_ce_work(asoc, cmd->obj.u32); 1512 break; 1513 1514 case SCTP_CMD_ECN_ECNE: 1515 /* Do delayed ECNE processing. */ 1516 new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32, 1517 chunk); 1518 if (new_obj) 1519 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1520 SCTP_CHUNK(new_obj)); 1521 break; 1522 1523 case SCTP_CMD_ECN_CWR: 1524 /* Do delayed CWR processing. */ 1525 sctp_do_ecn_cwr_work(asoc, cmd->obj.u32); 1526 break; 1527 1528 case SCTP_CMD_SETUP_T2: 1529 sctp_cmd_setup_t2(commands, asoc, cmd->obj.chunk); 1530 break; 1531 1532 case SCTP_CMD_TIMER_START_ONCE: 1533 timer = &asoc->timers[cmd->obj.to]; 1534 1535 if (timer_pending(timer)) 1536 break; 1537 fallthrough; 1538 1539 case SCTP_CMD_TIMER_START: 1540 timer = &asoc->timers[cmd->obj.to]; 1541 timeout = asoc->timeouts[cmd->obj.to]; 1542 BUG_ON(!timeout); 1543 1544 /* 1545 * SCTP has a hard time with timer starts. Because we process 1546 * timer starts as side effects, it can be hard to tell if we 1547 * have already started a timer or not, which leads to BUG 1548 * halts when we call add_timer. So here, instead of just starting 1549 * a timer, if the timer is already started, and just mod 1550 * the timer with the shorter of the two expiration times 1551 */ 1552 if (!timer_pending(timer)) 1553 sctp_association_hold(asoc); 1554 timer_reduce(timer, jiffies + timeout); 1555 break; 1556 1557 case SCTP_CMD_TIMER_RESTART: 1558 timer = &asoc->timers[cmd->obj.to]; 1559 timeout = asoc->timeouts[cmd->obj.to]; 1560 if (!mod_timer(timer, jiffies + timeout)) 1561 sctp_association_hold(asoc); 1562 break; 1563 1564 case SCTP_CMD_TIMER_STOP: 1565 timer = &asoc->timers[cmd->obj.to]; 1566 if (timer_delete(timer)) 1567 sctp_association_put(asoc); 1568 break; 1569 1570 case SCTP_CMD_INIT_CHOOSE_TRANSPORT: 1571 chunk = cmd->obj.chunk; 1572 t = sctp_assoc_choose_alter_transport(asoc, 1573 asoc->init_last_sent_to); 1574 asoc->init_last_sent_to = t; 1575 chunk->transport = t; 1576 t->init_sent_count++; 1577 /* Set the new transport as primary */ 1578 sctp_assoc_set_primary(asoc, t); 1579 break; 1580 1581 case SCTP_CMD_INIT_RESTART: 1582 /* Do the needed accounting and updates 1583 * associated with restarting an initialization 1584 * timer. Only multiply the timeout by two if 1585 * all transports have been tried at the current 1586 * timeout. 1587 */ 1588 sctp_cmd_t1_timer_update(asoc, 1589 SCTP_EVENT_TIMEOUT_T1_INIT, 1590 "INIT"); 1591 1592 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 1593 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 1594 break; 1595 1596 case SCTP_CMD_COOKIEECHO_RESTART: 1597 /* Do the needed accounting and updates 1598 * associated with restarting an initialization 1599 * timer. Only multiply the timeout by two if 1600 * all transports have been tried at the current 1601 * timeout. 1602 */ 1603 sctp_cmd_t1_timer_update(asoc, 1604 SCTP_EVENT_TIMEOUT_T1_COOKIE, 1605 "COOKIE"); 1606 1607 /* If we've sent any data bundled with 1608 * COOKIE-ECHO we need to resend. 1609 */ 1610 list_for_each_entry(t, &asoc->peer.transport_addr_list, 1611 transports) { 1612 sctp_retransmit_mark(&asoc->outqueue, t, 1613 SCTP_RTXR_T1_RTX); 1614 } 1615 1616 sctp_add_cmd_sf(commands, 1617 SCTP_CMD_TIMER_RESTART, 1618 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 1619 break; 1620 1621 case SCTP_CMD_INIT_FAILED: 1622 sctp_cmd_init_failed(commands, asoc, cmd->obj.u16); 1623 break; 1624 1625 case SCTP_CMD_ASSOC_FAILED: 1626 sctp_cmd_assoc_failed(commands, asoc, event_type, 1627 subtype, chunk, cmd->obj.u16); 1628 break; 1629 1630 case SCTP_CMD_INIT_COUNTER_INC: 1631 asoc->init_err_counter++; 1632 break; 1633 1634 case SCTP_CMD_INIT_COUNTER_RESET: 1635 asoc->init_err_counter = 0; 1636 asoc->init_cycle = 0; 1637 list_for_each_entry(t, &asoc->peer.transport_addr_list, 1638 transports) { 1639 t->init_sent_count = 0; 1640 } 1641 break; 1642 1643 case SCTP_CMD_REPORT_DUP: 1644 sctp_tsnmap_mark_dup(&asoc->peer.tsn_map, 1645 cmd->obj.u32); 1646 break; 1647 1648 case SCTP_CMD_REPORT_BAD_TAG: 1649 pr_debug("%s: vtag mismatch!\n", __func__); 1650 break; 1651 1652 case SCTP_CMD_STRIKE: 1653 /* Mark one strike against a transport. */ 1654 sctp_do_8_2_transport_strike(commands, asoc, 1655 cmd->obj.transport, 0); 1656 break; 1657 1658 case SCTP_CMD_TRANSPORT_IDLE: 1659 t = cmd->obj.transport; 1660 sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE); 1661 break; 1662 1663 case SCTP_CMD_TRANSPORT_HB_SENT: 1664 t = cmd->obj.transport; 1665 sctp_do_8_2_transport_strike(commands, asoc, 1666 t, 1); 1667 t->hb_sent = 1; 1668 break; 1669 1670 case SCTP_CMD_TRANSPORT_ON: 1671 t = cmd->obj.transport; 1672 sctp_cmd_transport_on(commands, asoc, t, chunk); 1673 break; 1674 1675 case SCTP_CMD_HB_TIMERS_START: 1676 sctp_cmd_hb_timers_start(commands, asoc); 1677 break; 1678 1679 case SCTP_CMD_HB_TIMER_UPDATE: 1680 t = cmd->obj.transport; 1681 sctp_transport_reset_hb_timer(t); 1682 break; 1683 1684 case SCTP_CMD_HB_TIMERS_STOP: 1685 sctp_cmd_hb_timers_stop(commands, asoc); 1686 break; 1687 1688 case SCTP_CMD_PROBE_TIMER_UPDATE: 1689 t = cmd->obj.transport; 1690 sctp_transport_reset_probe_timer(t); 1691 break; 1692 1693 case SCTP_CMD_REPORT_ERROR: 1694 error = cmd->obj.error; 1695 break; 1696 1697 case SCTP_CMD_PROCESS_CTSN: 1698 /* Dummy up a SACK for processing. */ 1699 sackh.cum_tsn_ack = cmd->obj.be32; 1700 sackh.a_rwnd = htonl(asoc->peer.rwnd + 1701 asoc->outqueue.outstanding_bytes); 1702 sackh.num_gap_ack_blocks = 0; 1703 sackh.num_dup_tsns = 0; 1704 chunk->subh.sack_hdr = &sackh; 1705 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, 1706 SCTP_CHUNK(chunk)); 1707 break; 1708 1709 case SCTP_CMD_DISCARD_PACKET: 1710 /* We need to discard the whole packet. 1711 * Uncork the queue since there might be 1712 * responses pending 1713 */ 1714 chunk->pdiscard = 1; 1715 if (asoc) { 1716 sctp_outq_uncork(&asoc->outqueue, gfp); 1717 local_cork = 0; 1718 } 1719 break; 1720 1721 case SCTP_CMD_RTO_PENDING: 1722 t = cmd->obj.transport; 1723 t->rto_pending = 1; 1724 break; 1725 1726 case SCTP_CMD_PART_DELIVER: 1727 asoc->stream.si->start_pd(&asoc->ulpq, GFP_ATOMIC); 1728 break; 1729 1730 case SCTP_CMD_RENEGE: 1731 asoc->stream.si->renege_events(&asoc->ulpq, 1732 cmd->obj.chunk, 1733 GFP_ATOMIC); 1734 break; 1735 1736 case SCTP_CMD_SETUP_T4: 1737 sctp_cmd_setup_t4(commands, asoc, cmd->obj.chunk); 1738 break; 1739 1740 case SCTP_CMD_PROCESS_OPERR: 1741 sctp_cmd_process_operr(commands, asoc, chunk); 1742 break; 1743 case SCTP_CMD_CLEAR_INIT_TAG: 1744 asoc->peer.i.init_tag = 0; 1745 break; 1746 case SCTP_CMD_DEL_NON_PRIMARY: 1747 sctp_cmd_del_non_primary(asoc); 1748 break; 1749 case SCTP_CMD_T3_RTX_TIMERS_STOP: 1750 sctp_cmd_t3_rtx_timers_stop(commands, asoc); 1751 break; 1752 case SCTP_CMD_FORCE_PRIM_RETRAN: 1753 t = asoc->peer.retran_path; 1754 asoc->peer.retran_path = asoc->peer.primary_path; 1755 sctp_outq_uncork(&asoc->outqueue, gfp); 1756 local_cork = 0; 1757 asoc->peer.retran_path = t; 1758 break; 1759 case SCTP_CMD_SET_SK_ERR: 1760 sctp_cmd_set_sk_err(asoc, cmd->obj.error); 1761 break; 1762 case SCTP_CMD_ASSOC_CHANGE: 1763 sctp_cmd_assoc_change(commands, asoc, 1764 cmd->obj.u8); 1765 break; 1766 case SCTP_CMD_ADAPTATION_IND: 1767 sctp_cmd_adaptation_ind(commands, asoc); 1768 break; 1769 case SCTP_CMD_PEER_NO_AUTH: 1770 sctp_cmd_peer_no_auth(commands, asoc); 1771 break; 1772 1773 case SCTP_CMD_ASSOC_SHKEY: 1774 error = sctp_auth_asoc_init_active_key(asoc, 1775 GFP_ATOMIC); 1776 break; 1777 case SCTP_CMD_UPDATE_INITTAG: 1778 asoc->peer.i.init_tag = cmd->obj.u32; 1779 break; 1780 case SCTP_CMD_SEND_MSG: 1781 if (!asoc->outqueue.cork) { 1782 sctp_outq_cork(&asoc->outqueue); 1783 local_cork = 1; 1784 } 1785 sctp_cmd_send_msg(asoc, cmd->obj.msg, gfp); 1786 break; 1787 case SCTP_CMD_PURGE_ASCONF_QUEUE: 1788 sctp_asconf_queue_teardown(asoc); 1789 break; 1790 1791 case SCTP_CMD_SET_ASOC: 1792 if (asoc && local_cork) { 1793 sctp_outq_uncork(&asoc->outqueue, gfp); 1794 local_cork = 0; 1795 } 1796 asoc = cmd->obj.asoc; 1797 break; 1798 1799 default: 1800 pr_warn("Impossible command: %u\n", 1801 cmd->verb); 1802 break; 1803 } 1804 1805 if (error) { 1806 cmd = sctp_next_cmd(commands); 1807 while (cmd) { 1808 if (cmd->verb == SCTP_CMD_REPLY) 1809 sctp_chunk_free(cmd->obj.chunk); 1810 cmd = sctp_next_cmd(commands); 1811 } 1812 break; 1813 } 1814 } 1815 1816 /* If this is in response to a received chunk, wait until 1817 * we are done with the packet to open the queue so that we don't 1818 * send multiple packets in response to a single request. 1819 */ 1820 if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) { 1821 if (chunk->end_of_packet || chunk->singleton) 1822 sctp_outq_uncork(&asoc->outqueue, gfp); 1823 } else if (local_cork) 1824 sctp_outq_uncork(&asoc->outqueue, gfp); 1825 1826 if (sp->data_ready_signalled) 1827 sp->data_ready_signalled = 0; 1828 1829 return error; 1830 } 1831