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