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 /* This happens when the response arrives after the timer is triggered. */ 462 if (!asoc->strreset_chunk) 463 goto out_unlock; 464 465 error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT, 466 SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_RECONF), 467 asoc->state, asoc->ep, asoc, 468 transport, GFP_ATOMIC); 469 470 if (error) 471 sk->sk_err = -error; 472 473 out_unlock: 474 bh_unlock_sock(sk); 475 sctp_transport_put(transport); 476 } 477 478 /* Handle the timeout of the probe timer. */ 479 void sctp_generate_probe_event(struct timer_list *t) 480 { 481 struct sctp_transport *transport = from_timer(transport, t, probe_timer); 482 struct sctp_association *asoc = transport->asoc; 483 struct sock *sk = asoc->base.sk; 484 struct net *net = sock_net(sk); 485 int error = 0; 486 487 bh_lock_sock(sk); 488 if (sock_owned_by_user(sk)) { 489 pr_debug("%s: sock is busy\n", __func__); 490 491 /* Try again later. */ 492 if (!mod_timer(&transport->probe_timer, jiffies + (HZ / 20))) 493 sctp_transport_hold(transport); 494 goto out_unlock; 495 } 496 497 error = sctp_do_sm(net, SCTP_EVENT_T_TIMEOUT, 498 SCTP_ST_TIMEOUT(SCTP_EVENT_TIMEOUT_PROBE), 499 asoc->state, asoc->ep, asoc, 500 transport, GFP_ATOMIC); 501 502 if (error) 503 sk->sk_err = -error; 504 505 out_unlock: 506 bh_unlock_sock(sk); 507 sctp_transport_put(transport); 508 } 509 510 /* Inject a SACK Timeout event into the state machine. */ 511 static void sctp_generate_sack_event(struct timer_list *t) 512 { 513 struct sctp_association *asoc = 514 from_timer(asoc, t, timers[SCTP_EVENT_TIMEOUT_SACK]); 515 516 sctp_generate_timeout_event(asoc, SCTP_EVENT_TIMEOUT_SACK); 517 } 518 519 sctp_timer_event_t *sctp_timer_events[SCTP_NUM_TIMEOUT_TYPES] = { 520 [SCTP_EVENT_TIMEOUT_NONE] = NULL, 521 [SCTP_EVENT_TIMEOUT_T1_COOKIE] = sctp_generate_t1_cookie_event, 522 [SCTP_EVENT_TIMEOUT_T1_INIT] = sctp_generate_t1_init_event, 523 [SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = sctp_generate_t2_shutdown_event, 524 [SCTP_EVENT_TIMEOUT_T3_RTX] = NULL, 525 [SCTP_EVENT_TIMEOUT_T4_RTO] = sctp_generate_t4_rto_event, 526 [SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD] = 527 sctp_generate_t5_shutdown_guard_event, 528 [SCTP_EVENT_TIMEOUT_HEARTBEAT] = NULL, 529 [SCTP_EVENT_TIMEOUT_RECONF] = NULL, 530 [SCTP_EVENT_TIMEOUT_SACK] = sctp_generate_sack_event, 531 [SCTP_EVENT_TIMEOUT_AUTOCLOSE] = sctp_generate_autoclose_event, 532 }; 533 534 535 /* RFC 2960 8.2 Path Failure Detection 536 * 537 * When its peer endpoint is multi-homed, an endpoint should keep a 538 * error counter for each of the destination transport addresses of the 539 * peer endpoint. 540 * 541 * Each time the T3-rtx timer expires on any address, or when a 542 * HEARTBEAT sent to an idle address is not acknowledged within a RTO, 543 * the error counter of that destination address will be incremented. 544 * When the value in the error counter exceeds the protocol parameter 545 * 'Path.Max.Retrans' of that destination address, the endpoint should 546 * mark the destination transport address as inactive, and a 547 * notification SHOULD be sent to the upper layer. 548 * 549 */ 550 static void sctp_do_8_2_transport_strike(struct sctp_cmd_seq *commands, 551 struct sctp_association *asoc, 552 struct sctp_transport *transport, 553 int is_hb) 554 { 555 /* The check for association's overall error counter exceeding the 556 * threshold is done in the state function. 557 */ 558 /* We are here due to a timer expiration. If the timer was 559 * not a HEARTBEAT, then normal error tracking is done. 560 * If the timer was a heartbeat, we only increment error counts 561 * when we already have an outstanding HEARTBEAT that has not 562 * been acknowledged. 563 * Additionally, some tranport states inhibit error increments. 564 */ 565 if (!is_hb) { 566 asoc->overall_error_count++; 567 if (transport->state != SCTP_INACTIVE) 568 transport->error_count++; 569 } else if (transport->hb_sent) { 570 if (transport->state != SCTP_UNCONFIRMED) 571 asoc->overall_error_count++; 572 if (transport->state != SCTP_INACTIVE) 573 transport->error_count++; 574 } 575 576 /* If the transport error count is greater than the pf_retrans 577 * threshold, and less than pathmaxrtx, and if the current state 578 * is SCTP_ACTIVE, then mark this transport as Partially Failed, 579 * see SCTP Quick Failover Draft, section 5.1 580 */ 581 if (asoc->base.net->sctp.pf_enable && 582 transport->state == SCTP_ACTIVE && 583 transport->error_count < transport->pathmaxrxt && 584 transport->error_count > transport->pf_retrans) { 585 586 sctp_assoc_control_transport(asoc, transport, 587 SCTP_TRANSPORT_PF, 588 0); 589 590 /* Update the hb timer to resend a heartbeat every rto */ 591 sctp_transport_reset_hb_timer(transport); 592 } 593 594 if (transport->state != SCTP_INACTIVE && 595 (transport->error_count > transport->pathmaxrxt)) { 596 pr_debug("%s: association:%p transport addr:%pISpc failed\n", 597 __func__, asoc, &transport->ipaddr.sa); 598 599 sctp_assoc_control_transport(asoc, transport, 600 SCTP_TRANSPORT_DOWN, 601 SCTP_FAILED_THRESHOLD); 602 } 603 604 if (transport->error_count > transport->ps_retrans && 605 asoc->peer.primary_path == transport && 606 asoc->peer.active_path != transport) 607 sctp_assoc_set_primary(asoc, asoc->peer.active_path); 608 609 /* E2) For the destination address for which the timer 610 * expires, set RTO <- RTO * 2 ("back off the timer"). The 611 * maximum value discussed in rule C7 above (RTO.max) may be 612 * used to provide an upper bound to this doubling operation. 613 * 614 * Special Case: the first HB doesn't trigger exponential backoff. 615 * The first unacknowledged HB triggers it. We do this with a flag 616 * that indicates that we have an outstanding HB. 617 */ 618 if (!is_hb || transport->hb_sent) { 619 transport->rto = min((transport->rto * 2), transport->asoc->rto_max); 620 sctp_max_rto(asoc, transport); 621 } 622 } 623 624 /* Worker routine to handle INIT command failure. */ 625 static void sctp_cmd_init_failed(struct sctp_cmd_seq *commands, 626 struct sctp_association *asoc, 627 unsigned int error) 628 { 629 struct sctp_ulpevent *event; 630 631 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_CANT_STR_ASSOC, 632 (__u16)error, 0, 0, NULL, 633 GFP_ATOMIC); 634 635 if (event) 636 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 637 SCTP_ULPEVENT(event)); 638 639 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 640 SCTP_STATE(SCTP_STATE_CLOSED)); 641 642 /* SEND_FAILED sent later when cleaning up the association. */ 643 asoc->outqueue.error = error; 644 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 645 } 646 647 /* Worker routine to handle SCTP_CMD_ASSOC_FAILED. */ 648 static void sctp_cmd_assoc_failed(struct sctp_cmd_seq *commands, 649 struct sctp_association *asoc, 650 enum sctp_event_type event_type, 651 union sctp_subtype subtype, 652 struct sctp_chunk *chunk, 653 unsigned int error) 654 { 655 struct sctp_ulpevent *event; 656 struct sctp_chunk *abort; 657 658 /* Cancel any partial delivery in progress. */ 659 asoc->stream.si->abort_pd(&asoc->ulpq, GFP_ATOMIC); 660 661 if (event_type == SCTP_EVENT_T_CHUNK && subtype.chunk == SCTP_CID_ABORT) 662 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST, 663 (__u16)error, 0, 0, chunk, 664 GFP_ATOMIC); 665 else 666 event = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_LOST, 667 (__u16)error, 0, 0, NULL, 668 GFP_ATOMIC); 669 if (event) 670 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 671 SCTP_ULPEVENT(event)); 672 673 if (asoc->overall_error_count >= asoc->max_retrans) { 674 abort = sctp_make_violation_max_retrans(asoc, chunk); 675 if (abort) 676 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 677 SCTP_CHUNK(abort)); 678 } 679 680 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 681 SCTP_STATE(SCTP_STATE_CLOSED)); 682 683 /* SEND_FAILED sent later when cleaning up the association. */ 684 asoc->outqueue.error = error; 685 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 686 } 687 688 /* Process an init chunk (may be real INIT/INIT-ACK or an embedded INIT 689 * inside the cookie. In reality, this is only used for INIT-ACK processing 690 * since all other cases use "temporary" associations and can do all 691 * their work in statefuns directly. 692 */ 693 static int sctp_cmd_process_init(struct sctp_cmd_seq *commands, 694 struct sctp_association *asoc, 695 struct sctp_chunk *chunk, 696 struct sctp_init_chunk *peer_init, 697 gfp_t gfp) 698 { 699 int error; 700 701 /* We only process the init as a sideeffect in a single 702 * case. This is when we process the INIT-ACK. If we 703 * fail during INIT processing (due to malloc problems), 704 * just return the error and stop processing the stack. 705 */ 706 if (!sctp_process_init(asoc, chunk, sctp_source(chunk), peer_init, gfp)) 707 error = -ENOMEM; 708 else 709 error = 0; 710 711 return error; 712 } 713 714 /* Helper function to break out starting up of heartbeat timers. */ 715 static void sctp_cmd_hb_timers_start(struct sctp_cmd_seq *cmds, 716 struct sctp_association *asoc) 717 { 718 struct sctp_transport *t; 719 720 /* Start a heartbeat timer for each transport on the association. 721 * hold a reference on the transport to make sure none of 722 * the needed data structures go away. 723 */ 724 list_for_each_entry(t, &asoc->peer.transport_addr_list, transports) 725 sctp_transport_reset_hb_timer(t); 726 } 727 728 static void sctp_cmd_hb_timers_stop(struct sctp_cmd_seq *cmds, 729 struct sctp_association *asoc) 730 { 731 struct sctp_transport *t; 732 733 /* Stop all heartbeat timers. */ 734 735 list_for_each_entry(t, &asoc->peer.transport_addr_list, 736 transports) { 737 if (del_timer(&t->hb_timer)) 738 sctp_transport_put(t); 739 } 740 } 741 742 /* Helper function to stop any pending T3-RTX timers */ 743 static void sctp_cmd_t3_rtx_timers_stop(struct sctp_cmd_seq *cmds, 744 struct sctp_association *asoc) 745 { 746 struct sctp_transport *t; 747 748 list_for_each_entry(t, &asoc->peer.transport_addr_list, 749 transports) { 750 if (del_timer(&t->T3_rtx_timer)) 751 sctp_transport_put(t); 752 } 753 } 754 755 756 /* Helper function to handle the reception of an HEARTBEAT ACK. */ 757 static void sctp_cmd_transport_on(struct sctp_cmd_seq *cmds, 758 struct sctp_association *asoc, 759 struct sctp_transport *t, 760 struct sctp_chunk *chunk) 761 { 762 struct sctp_sender_hb_info *hbinfo; 763 int was_unconfirmed = 0; 764 765 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of the 766 * HEARTBEAT should clear the error counter of the destination 767 * transport address to which the HEARTBEAT was sent. 768 */ 769 t->error_count = 0; 770 771 /* 772 * Although RFC4960 specifies that the overall error count must 773 * be cleared when a HEARTBEAT ACK is received, we make an 774 * exception while in SHUTDOWN PENDING. If the peer keeps its 775 * window shut forever, we may never be able to transmit our 776 * outstanding data and rely on the retransmission limit be reached 777 * to shutdown the association. 778 */ 779 if (t->asoc->state < SCTP_STATE_SHUTDOWN_PENDING) 780 t->asoc->overall_error_count = 0; 781 782 /* Clear the hb_sent flag to signal that we had a good 783 * acknowledgement. 784 */ 785 t->hb_sent = 0; 786 787 /* Mark the destination transport address as active if it is not so 788 * marked. 789 */ 790 if ((t->state == SCTP_INACTIVE) || (t->state == SCTP_UNCONFIRMED)) { 791 was_unconfirmed = 1; 792 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP, 793 SCTP_HEARTBEAT_SUCCESS); 794 } 795 796 if (t->state == SCTP_PF) 797 sctp_assoc_control_transport(asoc, t, SCTP_TRANSPORT_UP, 798 SCTP_HEARTBEAT_SUCCESS); 799 800 /* HB-ACK was received for a the proper HB. Consider this 801 * forward progress. 802 */ 803 if (t->dst) 804 sctp_transport_dst_confirm(t); 805 806 /* The receiver of the HEARTBEAT ACK should also perform an 807 * RTT measurement for that destination transport address 808 * using the time value carried in the HEARTBEAT ACK chunk. 809 * If the transport's rto_pending variable has been cleared, 810 * it was most likely due to a retransmit. However, we want 811 * to re-enable it to properly update the rto. 812 */ 813 if (t->rto_pending == 0) 814 t->rto_pending = 1; 815 816 hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data; 817 sctp_transport_update_rto(t, (jiffies - hbinfo->sent_at)); 818 819 /* Update the heartbeat timer. */ 820 sctp_transport_reset_hb_timer(t); 821 822 if (was_unconfirmed && asoc->peer.transport_count == 1) 823 sctp_transport_immediate_rtx(t); 824 } 825 826 827 /* Helper function to process the process SACK command. */ 828 static int sctp_cmd_process_sack(struct sctp_cmd_seq *cmds, 829 struct sctp_association *asoc, 830 struct sctp_chunk *chunk) 831 { 832 int err = 0; 833 834 if (sctp_outq_sack(&asoc->outqueue, chunk)) { 835 /* There are no more TSNs awaiting SACK. */ 836 err = sctp_do_sm(asoc->base.net, SCTP_EVENT_T_OTHER, 837 SCTP_ST_OTHER(SCTP_EVENT_NO_PENDING_TSN), 838 asoc->state, asoc->ep, asoc, NULL, 839 GFP_ATOMIC); 840 } 841 842 return err; 843 } 844 845 /* Helper function to set the timeout value for T2-SHUTDOWN timer and to set 846 * the transport for a shutdown chunk. 847 */ 848 static void sctp_cmd_setup_t2(struct sctp_cmd_seq *cmds, 849 struct sctp_association *asoc, 850 struct sctp_chunk *chunk) 851 { 852 struct sctp_transport *t; 853 854 if (chunk->transport) 855 t = chunk->transport; 856 else { 857 t = sctp_assoc_choose_alter_transport(asoc, 858 asoc->shutdown_last_sent_to); 859 chunk->transport = t; 860 } 861 asoc->shutdown_last_sent_to = t; 862 asoc->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] = t->rto; 863 } 864 865 /* Helper function to change the state of an association. */ 866 static void sctp_cmd_new_state(struct sctp_cmd_seq *cmds, 867 struct sctp_association *asoc, 868 enum sctp_state state) 869 { 870 struct sock *sk = asoc->base.sk; 871 872 asoc->state = state; 873 874 pr_debug("%s: asoc:%p[%s]\n", __func__, asoc, sctp_state_tbl[state]); 875 876 if (sctp_style(sk, TCP)) { 877 /* Change the sk->sk_state of a TCP-style socket that has 878 * successfully completed a connect() call. 879 */ 880 if (sctp_state(asoc, ESTABLISHED) && sctp_sstate(sk, CLOSED)) 881 inet_sk_set_state(sk, SCTP_SS_ESTABLISHED); 882 883 /* Set the RCV_SHUTDOWN flag when a SHUTDOWN is received. */ 884 if (sctp_state(asoc, SHUTDOWN_RECEIVED) && 885 sctp_sstate(sk, ESTABLISHED)) { 886 inet_sk_set_state(sk, SCTP_SS_CLOSING); 887 sk->sk_shutdown |= RCV_SHUTDOWN; 888 } 889 } 890 891 if (sctp_state(asoc, COOKIE_WAIT)) { 892 /* Reset init timeouts since they may have been 893 * increased due to timer expirations. 894 */ 895 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] = 896 asoc->rto_initial; 897 asoc->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] = 898 asoc->rto_initial; 899 } 900 901 if (sctp_state(asoc, ESTABLISHED)) { 902 kfree(asoc->peer.cookie); 903 asoc->peer.cookie = NULL; 904 } 905 906 if (sctp_state(asoc, ESTABLISHED) || 907 sctp_state(asoc, CLOSED) || 908 sctp_state(asoc, SHUTDOWN_RECEIVED)) { 909 /* Wake up any processes waiting in the asoc's wait queue in 910 * sctp_wait_for_connect() or sctp_wait_for_sndbuf(). 911 */ 912 if (waitqueue_active(&asoc->wait)) 913 wake_up_interruptible(&asoc->wait); 914 915 /* Wake up any processes waiting in the sk's sleep queue of 916 * a TCP-style or UDP-style peeled-off socket in 917 * sctp_wait_for_accept() or sctp_wait_for_packet(). 918 * For a UDP-style socket, the waiters are woken up by the 919 * notifications. 920 */ 921 if (!sctp_style(sk, UDP)) 922 sk->sk_state_change(sk); 923 } 924 925 if (sctp_state(asoc, SHUTDOWN_PENDING) && 926 !sctp_outq_is_empty(&asoc->outqueue)) 927 sctp_outq_uncork(&asoc->outqueue, GFP_ATOMIC); 928 } 929 930 /* Helper function to delete an association. */ 931 static void sctp_cmd_delete_tcb(struct sctp_cmd_seq *cmds, 932 struct sctp_association *asoc) 933 { 934 struct sock *sk = asoc->base.sk; 935 936 /* If it is a non-temporary association belonging to a TCP-style 937 * listening socket that is not closed, do not free it so that accept() 938 * can pick it up later. 939 */ 940 if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING) && 941 (!asoc->temp) && (sk->sk_shutdown != SHUTDOWN_MASK)) 942 return; 943 944 sctp_association_free(asoc); 945 } 946 947 /* 948 * ADDIP Section 4.1 ASCONF Chunk Procedures 949 * A4) Start a T-4 RTO timer, using the RTO value of the selected 950 * destination address (we use active path instead of primary path just 951 * because primary path may be inactive. 952 */ 953 static void sctp_cmd_setup_t4(struct sctp_cmd_seq *cmds, 954 struct sctp_association *asoc, 955 struct sctp_chunk *chunk) 956 { 957 struct sctp_transport *t; 958 959 t = sctp_assoc_choose_alter_transport(asoc, chunk->transport); 960 asoc->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = t->rto; 961 chunk->transport = t; 962 } 963 964 /* Process an incoming Operation Error Chunk. */ 965 static void sctp_cmd_process_operr(struct sctp_cmd_seq *cmds, 966 struct sctp_association *asoc, 967 struct sctp_chunk *chunk) 968 { 969 struct sctp_errhdr *err_hdr; 970 struct sctp_ulpevent *ev; 971 972 while (chunk->chunk_end > chunk->skb->data) { 973 err_hdr = (struct sctp_errhdr *)(chunk->skb->data); 974 975 ev = sctp_ulpevent_make_remote_error(asoc, chunk, 0, 976 GFP_ATOMIC); 977 if (!ev) 978 return; 979 980 asoc->stream.si->enqueue_event(&asoc->ulpq, ev); 981 982 switch (err_hdr->cause) { 983 case SCTP_ERROR_UNKNOWN_CHUNK: 984 { 985 struct sctp_chunkhdr *unk_chunk_hdr; 986 987 unk_chunk_hdr = (struct sctp_chunkhdr *)(err_hdr + 1); 988 switch (unk_chunk_hdr->type) { 989 /* ADDIP 4.1 A9) If the peer responds to an ASCONF with 990 * an ERROR chunk reporting that it did not recognized 991 * the ASCONF chunk type, the sender of the ASCONF MUST 992 * NOT send any further ASCONF chunks and MUST stop its 993 * T-4 timer. 994 */ 995 case SCTP_CID_ASCONF: 996 if (asoc->peer.asconf_capable == 0) 997 break; 998 999 asoc->peer.asconf_capable = 0; 1000 sctp_add_cmd_sf(cmds, SCTP_CMD_TIMER_STOP, 1001 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 1002 break; 1003 default: 1004 break; 1005 } 1006 break; 1007 } 1008 default: 1009 break; 1010 } 1011 } 1012 } 1013 1014 /* Helper function to remove the association non-primary peer 1015 * transports. 1016 */ 1017 static void sctp_cmd_del_non_primary(struct sctp_association *asoc) 1018 { 1019 struct sctp_transport *t; 1020 struct list_head *temp; 1021 struct list_head *pos; 1022 1023 list_for_each_safe(pos, temp, &asoc->peer.transport_addr_list) { 1024 t = list_entry(pos, struct sctp_transport, transports); 1025 if (!sctp_cmp_addr_exact(&t->ipaddr, 1026 &asoc->peer.primary_addr)) { 1027 sctp_assoc_rm_peer(asoc, t); 1028 } 1029 } 1030 } 1031 1032 /* Helper function to set sk_err on a 1-1 style socket. */ 1033 static void sctp_cmd_set_sk_err(struct sctp_association *asoc, int error) 1034 { 1035 struct sock *sk = asoc->base.sk; 1036 1037 if (!sctp_style(sk, UDP)) 1038 sk->sk_err = error; 1039 } 1040 1041 /* Helper function to generate an association change event */ 1042 static void sctp_cmd_assoc_change(struct sctp_cmd_seq *commands, 1043 struct sctp_association *asoc, 1044 u8 state) 1045 { 1046 struct sctp_ulpevent *ev; 1047 1048 ev = sctp_ulpevent_make_assoc_change(asoc, 0, state, 0, 1049 asoc->c.sinit_num_ostreams, 1050 asoc->c.sinit_max_instreams, 1051 NULL, GFP_ATOMIC); 1052 if (ev) 1053 asoc->stream.si->enqueue_event(&asoc->ulpq, ev); 1054 } 1055 1056 static void sctp_cmd_peer_no_auth(struct sctp_cmd_seq *commands, 1057 struct sctp_association *asoc) 1058 { 1059 struct sctp_ulpevent *ev; 1060 1061 ev = sctp_ulpevent_make_authkey(asoc, 0, SCTP_AUTH_NO_AUTH, GFP_ATOMIC); 1062 if (ev) 1063 asoc->stream.si->enqueue_event(&asoc->ulpq, ev); 1064 } 1065 1066 /* Helper function to generate an adaptation indication event */ 1067 static void sctp_cmd_adaptation_ind(struct sctp_cmd_seq *commands, 1068 struct sctp_association *asoc) 1069 { 1070 struct sctp_ulpevent *ev; 1071 1072 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC); 1073 1074 if (ev) 1075 asoc->stream.si->enqueue_event(&asoc->ulpq, ev); 1076 } 1077 1078 1079 static void sctp_cmd_t1_timer_update(struct sctp_association *asoc, 1080 enum sctp_event_timeout timer, 1081 char *name) 1082 { 1083 struct sctp_transport *t; 1084 1085 t = asoc->init_last_sent_to; 1086 asoc->init_err_counter++; 1087 1088 if (t->init_sent_count > (asoc->init_cycle + 1)) { 1089 asoc->timeouts[timer] *= 2; 1090 if (asoc->timeouts[timer] > asoc->max_init_timeo) { 1091 asoc->timeouts[timer] = asoc->max_init_timeo; 1092 } 1093 asoc->init_cycle++; 1094 1095 pr_debug("%s: T1[%s] timeout adjustment init_err_counter:%d" 1096 " cycle:%d timeout:%ld\n", __func__, name, 1097 asoc->init_err_counter, asoc->init_cycle, 1098 asoc->timeouts[timer]); 1099 } 1100 1101 } 1102 1103 /* Send the whole message, chunk by chunk, to the outqueue. 1104 * This way the whole message is queued up and bundling if 1105 * encouraged for small fragments. 1106 */ 1107 static void sctp_cmd_send_msg(struct sctp_association *asoc, 1108 struct sctp_datamsg *msg, gfp_t gfp) 1109 { 1110 struct sctp_chunk *chunk; 1111 1112 list_for_each_entry(chunk, &msg->chunks, frag_list) 1113 sctp_outq_tail(&asoc->outqueue, chunk, gfp); 1114 1115 asoc->outqueue.sched->enqueue(&asoc->outqueue, msg); 1116 } 1117 1118 1119 /* These three macros allow us to pull the debugging code out of the 1120 * main flow of sctp_do_sm() to keep attention focused on the real 1121 * functionality there. 1122 */ 1123 #define debug_pre_sfn() \ 1124 pr_debug("%s[pre-fn]: ep:%p, %s, %s, asoc:%p[%s], %s\n", __func__, \ 1125 ep, sctp_evttype_tbl[event_type], (*debug_fn)(subtype), \ 1126 asoc, sctp_state_tbl[state], state_fn->name) 1127 1128 #define debug_post_sfn() \ 1129 pr_debug("%s[post-fn]: asoc:%p, status:%s\n", __func__, asoc, \ 1130 sctp_status_tbl[status]) 1131 1132 #define debug_post_sfx() \ 1133 pr_debug("%s[post-sfx]: error:%d, asoc:%p[%s]\n", __func__, error, \ 1134 asoc, sctp_state_tbl[(asoc && sctp_id2assoc(ep->base.sk, \ 1135 sctp_assoc2id(asoc))) ? asoc->state : SCTP_STATE_CLOSED]) 1136 1137 /* 1138 * This is the master state machine processing function. 1139 * 1140 * If you want to understand all of lksctp, this is a 1141 * good place to start. 1142 */ 1143 int sctp_do_sm(struct net *net, enum sctp_event_type event_type, 1144 union sctp_subtype subtype, enum sctp_state state, 1145 struct sctp_endpoint *ep, struct sctp_association *asoc, 1146 void *event_arg, gfp_t gfp) 1147 { 1148 typedef const char *(printfn_t)(union sctp_subtype); 1149 static printfn_t *table[] = { 1150 NULL, sctp_cname, sctp_tname, sctp_oname, sctp_pname, 1151 }; 1152 printfn_t *debug_fn __attribute__ ((unused)) = table[event_type]; 1153 const struct sctp_sm_table_entry *state_fn; 1154 struct sctp_cmd_seq commands; 1155 enum sctp_disposition status; 1156 int error = 0; 1157 1158 /* Look up the state function, run it, and then process the 1159 * side effects. These three steps are the heart of lksctp. 1160 */ 1161 state_fn = sctp_sm_lookup_event(net, event_type, state, subtype); 1162 1163 sctp_init_cmd_seq(&commands); 1164 1165 debug_pre_sfn(); 1166 status = state_fn->fn(net, ep, asoc, subtype, event_arg, &commands); 1167 debug_post_sfn(); 1168 1169 error = sctp_side_effects(event_type, subtype, state, 1170 ep, &asoc, event_arg, status, 1171 &commands, gfp); 1172 debug_post_sfx(); 1173 1174 return error; 1175 } 1176 1177 /***************************************************************** 1178 * This the master state function side effect processing function. 1179 *****************************************************************/ 1180 static int sctp_side_effects(enum sctp_event_type event_type, 1181 union sctp_subtype subtype, 1182 enum sctp_state state, 1183 struct sctp_endpoint *ep, 1184 struct sctp_association **asoc, 1185 void *event_arg, 1186 enum sctp_disposition status, 1187 struct sctp_cmd_seq *commands, 1188 gfp_t gfp) 1189 { 1190 int error; 1191 1192 /* FIXME - Most of the dispositions left today would be categorized 1193 * as "exceptional" dispositions. For those dispositions, it 1194 * may not be proper to run through any of the commands at all. 1195 * For example, the command interpreter might be run only with 1196 * disposition SCTP_DISPOSITION_CONSUME. 1197 */ 1198 if (0 != (error = sctp_cmd_interpreter(event_type, subtype, state, 1199 ep, *asoc, 1200 event_arg, status, 1201 commands, gfp))) 1202 goto bail; 1203 1204 switch (status) { 1205 case SCTP_DISPOSITION_DISCARD: 1206 pr_debug("%s: ignored sctp protocol event - state:%d, " 1207 "event_type:%d, event_id:%d\n", __func__, state, 1208 event_type, subtype.chunk); 1209 break; 1210 1211 case SCTP_DISPOSITION_NOMEM: 1212 /* We ran out of memory, so we need to discard this 1213 * packet. 1214 */ 1215 /* BUG--we should now recover some memory, probably by 1216 * reneging... 1217 */ 1218 error = -ENOMEM; 1219 break; 1220 1221 case SCTP_DISPOSITION_DELETE_TCB: 1222 case SCTP_DISPOSITION_ABORT: 1223 /* This should now be a command. */ 1224 *asoc = NULL; 1225 break; 1226 1227 case SCTP_DISPOSITION_CONSUME: 1228 /* 1229 * We should no longer have much work to do here as the 1230 * real work has been done as explicit commands above. 1231 */ 1232 break; 1233 1234 case SCTP_DISPOSITION_VIOLATION: 1235 net_err_ratelimited("protocol violation state %d chunkid %d\n", 1236 state, subtype.chunk); 1237 break; 1238 1239 case SCTP_DISPOSITION_NOT_IMPL: 1240 pr_warn("unimplemented feature in state %d, event_type %d, event_id %d\n", 1241 state, event_type, subtype.chunk); 1242 break; 1243 1244 case SCTP_DISPOSITION_BUG: 1245 pr_err("bug in state %d, event_type %d, event_id %d\n", 1246 state, event_type, subtype.chunk); 1247 BUG(); 1248 break; 1249 1250 default: 1251 pr_err("impossible disposition %d in state %d, event_type %d, event_id %d\n", 1252 status, state, event_type, subtype.chunk); 1253 BUG(); 1254 break; 1255 } 1256 1257 bail: 1258 return error; 1259 } 1260 1261 /******************************************************************** 1262 * 2nd Level Abstractions 1263 ********************************************************************/ 1264 1265 /* This is the side-effect interpreter. */ 1266 static int sctp_cmd_interpreter(enum sctp_event_type event_type, 1267 union sctp_subtype subtype, 1268 enum sctp_state state, 1269 struct sctp_endpoint *ep, 1270 struct sctp_association *asoc, 1271 void *event_arg, 1272 enum sctp_disposition status, 1273 struct sctp_cmd_seq *commands, 1274 gfp_t gfp) 1275 { 1276 struct sctp_sock *sp = sctp_sk(ep->base.sk); 1277 struct sctp_chunk *chunk = NULL, *new_obj; 1278 struct sctp_packet *packet; 1279 struct sctp_sackhdr sackh; 1280 struct timer_list *timer; 1281 struct sctp_transport *t; 1282 unsigned long timeout; 1283 struct sctp_cmd *cmd; 1284 int local_cork = 0; 1285 int error = 0; 1286 int force; 1287 1288 if (SCTP_EVENT_T_TIMEOUT != event_type) 1289 chunk = event_arg; 1290 1291 /* Note: This whole file is a huge candidate for rework. 1292 * For example, each command could either have its own handler, so 1293 * the loop would look like: 1294 * while (cmds) 1295 * cmd->handle(x, y, z) 1296 * --jgrimm 1297 */ 1298 while (NULL != (cmd = sctp_next_cmd(commands))) { 1299 switch (cmd->verb) { 1300 case SCTP_CMD_NOP: 1301 /* Do nothing. */ 1302 break; 1303 1304 case SCTP_CMD_NEW_ASOC: 1305 /* Register a new association. */ 1306 if (local_cork) { 1307 sctp_outq_uncork(&asoc->outqueue, gfp); 1308 local_cork = 0; 1309 } 1310 1311 /* Register with the endpoint. */ 1312 asoc = cmd->obj.asoc; 1313 BUG_ON(asoc->peer.primary_path == NULL); 1314 sctp_endpoint_add_asoc(ep, asoc); 1315 break; 1316 1317 case SCTP_CMD_PURGE_OUTQUEUE: 1318 sctp_outq_teardown(&asoc->outqueue); 1319 break; 1320 1321 case SCTP_CMD_DELETE_TCB: 1322 if (local_cork) { 1323 sctp_outq_uncork(&asoc->outqueue, gfp); 1324 local_cork = 0; 1325 } 1326 /* Delete the current association. */ 1327 sctp_cmd_delete_tcb(commands, asoc); 1328 asoc = NULL; 1329 break; 1330 1331 case SCTP_CMD_NEW_STATE: 1332 /* Enter a new state. */ 1333 sctp_cmd_new_state(commands, asoc, cmd->obj.state); 1334 break; 1335 1336 case SCTP_CMD_REPORT_TSN: 1337 /* Record the arrival of a TSN. */ 1338 error = sctp_tsnmap_mark(&asoc->peer.tsn_map, 1339 cmd->obj.u32, NULL); 1340 break; 1341 1342 case SCTP_CMD_REPORT_FWDTSN: 1343 asoc->stream.si->report_ftsn(&asoc->ulpq, cmd->obj.u32); 1344 break; 1345 1346 case SCTP_CMD_PROCESS_FWDTSN: 1347 asoc->stream.si->handle_ftsn(&asoc->ulpq, 1348 cmd->obj.chunk); 1349 break; 1350 1351 case SCTP_CMD_GEN_SACK: 1352 /* Generate a Selective ACK. 1353 * The argument tells us whether to just count 1354 * the packet and MAYBE generate a SACK, or 1355 * force a SACK out. 1356 */ 1357 force = cmd->obj.i32; 1358 error = sctp_gen_sack(asoc, force, commands); 1359 break; 1360 1361 case SCTP_CMD_PROCESS_SACK: 1362 /* Process an inbound SACK. */ 1363 error = sctp_cmd_process_sack(commands, asoc, 1364 cmd->obj.chunk); 1365 break; 1366 1367 case SCTP_CMD_GEN_INIT_ACK: 1368 /* Generate an INIT ACK chunk. */ 1369 new_obj = sctp_make_init_ack(asoc, chunk, GFP_ATOMIC, 1370 0); 1371 if (!new_obj) { 1372 error = -ENOMEM; 1373 break; 1374 } 1375 1376 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1377 SCTP_CHUNK(new_obj)); 1378 break; 1379 1380 case SCTP_CMD_PEER_INIT: 1381 /* Process a unified INIT from the peer. 1382 * Note: Only used during INIT-ACK processing. If 1383 * there is an error just return to the outter 1384 * layer which will bail. 1385 */ 1386 error = sctp_cmd_process_init(commands, asoc, chunk, 1387 cmd->obj.init, gfp); 1388 break; 1389 1390 case SCTP_CMD_GEN_COOKIE_ECHO: 1391 /* Generate a COOKIE ECHO chunk. */ 1392 new_obj = sctp_make_cookie_echo(asoc, chunk); 1393 if (!new_obj) { 1394 if (cmd->obj.chunk) 1395 sctp_chunk_free(cmd->obj.chunk); 1396 error = -ENOMEM; 1397 break; 1398 } 1399 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1400 SCTP_CHUNK(new_obj)); 1401 1402 /* If there is an ERROR chunk to be sent along with 1403 * the COOKIE_ECHO, send it, too. 1404 */ 1405 if (cmd->obj.chunk) 1406 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1407 SCTP_CHUNK(cmd->obj.chunk)); 1408 1409 if (new_obj->transport) { 1410 new_obj->transport->init_sent_count++; 1411 asoc->init_last_sent_to = new_obj->transport; 1412 } 1413 1414 /* FIXME - Eventually come up with a cleaner way to 1415 * enabling COOKIE-ECHO + DATA bundling during 1416 * multihoming stale cookie scenarios, the following 1417 * command plays with asoc->peer.retran_path to 1418 * avoid the problem of sending the COOKIE-ECHO and 1419 * DATA in different paths, which could result 1420 * in the association being ABORTed if the DATA chunk 1421 * is processed first by the server. Checking the 1422 * init error counter simply causes this command 1423 * to be executed only during failed attempts of 1424 * association establishment. 1425 */ 1426 if ((asoc->peer.retran_path != 1427 asoc->peer.primary_path) && 1428 (asoc->init_err_counter > 0)) { 1429 sctp_add_cmd_sf(commands, 1430 SCTP_CMD_FORCE_PRIM_RETRAN, 1431 SCTP_NULL()); 1432 } 1433 1434 break; 1435 1436 case SCTP_CMD_GEN_SHUTDOWN: 1437 /* Generate SHUTDOWN when in SHUTDOWN_SENT state. 1438 * Reset error counts. 1439 */ 1440 asoc->overall_error_count = 0; 1441 1442 /* Generate a SHUTDOWN chunk. */ 1443 new_obj = sctp_make_shutdown(asoc, chunk); 1444 if (!new_obj) { 1445 error = -ENOMEM; 1446 break; 1447 } 1448 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1449 SCTP_CHUNK(new_obj)); 1450 break; 1451 1452 case SCTP_CMD_CHUNK_ULP: 1453 /* Send a chunk to the sockets layer. */ 1454 pr_debug("%s: sm_sideff: chunk_up:%p, ulpq:%p\n", 1455 __func__, cmd->obj.chunk, &asoc->ulpq); 1456 1457 asoc->stream.si->ulpevent_data(&asoc->ulpq, 1458 cmd->obj.chunk, 1459 GFP_ATOMIC); 1460 break; 1461 1462 case SCTP_CMD_EVENT_ULP: 1463 /* Send a notification to the sockets layer. */ 1464 pr_debug("%s: sm_sideff: event_up:%p, ulpq:%p\n", 1465 __func__, cmd->obj.ulpevent, &asoc->ulpq); 1466 1467 asoc->stream.si->enqueue_event(&asoc->ulpq, 1468 cmd->obj.ulpevent); 1469 break; 1470 1471 case SCTP_CMD_REPLY: 1472 /* If an caller has not already corked, do cork. */ 1473 if (!asoc->outqueue.cork) { 1474 sctp_outq_cork(&asoc->outqueue); 1475 local_cork = 1; 1476 } 1477 /* Send a chunk to our peer. */ 1478 sctp_outq_tail(&asoc->outqueue, cmd->obj.chunk, gfp); 1479 break; 1480 1481 case SCTP_CMD_SEND_PKT: 1482 /* Send a full packet to our peer. */ 1483 packet = cmd->obj.packet; 1484 sctp_packet_transmit(packet, gfp); 1485 sctp_ootb_pkt_free(packet); 1486 break; 1487 1488 case SCTP_CMD_T1_RETRAN: 1489 /* Mark a transport for retransmission. */ 1490 sctp_retransmit(&asoc->outqueue, cmd->obj.transport, 1491 SCTP_RTXR_T1_RTX); 1492 break; 1493 1494 case SCTP_CMD_RETRAN: 1495 /* Mark a transport for retransmission. */ 1496 sctp_retransmit(&asoc->outqueue, cmd->obj.transport, 1497 SCTP_RTXR_T3_RTX); 1498 break; 1499 1500 case SCTP_CMD_ECN_CE: 1501 /* Do delayed CE processing. */ 1502 sctp_do_ecn_ce_work(asoc, cmd->obj.u32); 1503 break; 1504 1505 case SCTP_CMD_ECN_ECNE: 1506 /* Do delayed ECNE processing. */ 1507 new_obj = sctp_do_ecn_ecne_work(asoc, cmd->obj.u32, 1508 chunk); 1509 if (new_obj) 1510 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1511 SCTP_CHUNK(new_obj)); 1512 break; 1513 1514 case SCTP_CMD_ECN_CWR: 1515 /* Do delayed CWR processing. */ 1516 sctp_do_ecn_cwr_work(asoc, cmd->obj.u32); 1517 break; 1518 1519 case SCTP_CMD_SETUP_T2: 1520 sctp_cmd_setup_t2(commands, asoc, cmd->obj.chunk); 1521 break; 1522 1523 case SCTP_CMD_TIMER_START_ONCE: 1524 timer = &asoc->timers[cmd->obj.to]; 1525 1526 if (timer_pending(timer)) 1527 break; 1528 fallthrough; 1529 1530 case SCTP_CMD_TIMER_START: 1531 timer = &asoc->timers[cmd->obj.to]; 1532 timeout = asoc->timeouts[cmd->obj.to]; 1533 BUG_ON(!timeout); 1534 1535 /* 1536 * SCTP has a hard time with timer starts. Because we process 1537 * timer starts as side effects, it can be hard to tell if we 1538 * have already started a timer or not, which leads to BUG 1539 * halts when we call add_timer. So here, instead of just starting 1540 * a timer, if the timer is already started, and just mod 1541 * the timer with the shorter of the two expiration times 1542 */ 1543 if (!timer_pending(timer)) 1544 sctp_association_hold(asoc); 1545 timer_reduce(timer, jiffies + timeout); 1546 break; 1547 1548 case SCTP_CMD_TIMER_RESTART: 1549 timer = &asoc->timers[cmd->obj.to]; 1550 timeout = asoc->timeouts[cmd->obj.to]; 1551 if (!mod_timer(timer, jiffies + timeout)) 1552 sctp_association_hold(asoc); 1553 break; 1554 1555 case SCTP_CMD_TIMER_STOP: 1556 timer = &asoc->timers[cmd->obj.to]; 1557 if (del_timer(timer)) 1558 sctp_association_put(asoc); 1559 break; 1560 1561 case SCTP_CMD_INIT_CHOOSE_TRANSPORT: 1562 chunk = cmd->obj.chunk; 1563 t = sctp_assoc_choose_alter_transport(asoc, 1564 asoc->init_last_sent_to); 1565 asoc->init_last_sent_to = t; 1566 chunk->transport = t; 1567 t->init_sent_count++; 1568 /* Set the new transport as primary */ 1569 sctp_assoc_set_primary(asoc, t); 1570 break; 1571 1572 case SCTP_CMD_INIT_RESTART: 1573 /* Do the needed accounting and updates 1574 * associated with restarting an initialization 1575 * timer. Only multiply the timeout by two if 1576 * all transports have been tried at the current 1577 * timeout. 1578 */ 1579 sctp_cmd_t1_timer_update(asoc, 1580 SCTP_EVENT_TIMEOUT_T1_INIT, 1581 "INIT"); 1582 1583 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 1584 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 1585 break; 1586 1587 case SCTP_CMD_COOKIEECHO_RESTART: 1588 /* Do the needed accounting and updates 1589 * associated with restarting an initialization 1590 * timer. Only multiply the timeout by two if 1591 * all transports have been tried at the current 1592 * timeout. 1593 */ 1594 sctp_cmd_t1_timer_update(asoc, 1595 SCTP_EVENT_TIMEOUT_T1_COOKIE, 1596 "COOKIE"); 1597 1598 /* If we've sent any data bundled with 1599 * COOKIE-ECHO we need to resend. 1600 */ 1601 list_for_each_entry(t, &asoc->peer.transport_addr_list, 1602 transports) { 1603 sctp_retransmit_mark(&asoc->outqueue, t, 1604 SCTP_RTXR_T1_RTX); 1605 } 1606 1607 sctp_add_cmd_sf(commands, 1608 SCTP_CMD_TIMER_RESTART, 1609 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 1610 break; 1611 1612 case SCTP_CMD_INIT_FAILED: 1613 sctp_cmd_init_failed(commands, asoc, cmd->obj.u16); 1614 break; 1615 1616 case SCTP_CMD_ASSOC_FAILED: 1617 sctp_cmd_assoc_failed(commands, asoc, event_type, 1618 subtype, chunk, cmd->obj.u16); 1619 break; 1620 1621 case SCTP_CMD_INIT_COUNTER_INC: 1622 asoc->init_err_counter++; 1623 break; 1624 1625 case SCTP_CMD_INIT_COUNTER_RESET: 1626 asoc->init_err_counter = 0; 1627 asoc->init_cycle = 0; 1628 list_for_each_entry(t, &asoc->peer.transport_addr_list, 1629 transports) { 1630 t->init_sent_count = 0; 1631 } 1632 break; 1633 1634 case SCTP_CMD_REPORT_DUP: 1635 sctp_tsnmap_mark_dup(&asoc->peer.tsn_map, 1636 cmd->obj.u32); 1637 break; 1638 1639 case SCTP_CMD_REPORT_BAD_TAG: 1640 pr_debug("%s: vtag mismatch!\n", __func__); 1641 break; 1642 1643 case SCTP_CMD_STRIKE: 1644 /* Mark one strike against a transport. */ 1645 sctp_do_8_2_transport_strike(commands, asoc, 1646 cmd->obj.transport, 0); 1647 break; 1648 1649 case SCTP_CMD_TRANSPORT_IDLE: 1650 t = cmd->obj.transport; 1651 sctp_transport_lower_cwnd(t, SCTP_LOWER_CWND_INACTIVE); 1652 break; 1653 1654 case SCTP_CMD_TRANSPORT_HB_SENT: 1655 t = cmd->obj.transport; 1656 sctp_do_8_2_transport_strike(commands, asoc, 1657 t, 1); 1658 t->hb_sent = 1; 1659 break; 1660 1661 case SCTP_CMD_TRANSPORT_ON: 1662 t = cmd->obj.transport; 1663 sctp_cmd_transport_on(commands, asoc, t, chunk); 1664 break; 1665 1666 case SCTP_CMD_HB_TIMERS_START: 1667 sctp_cmd_hb_timers_start(commands, asoc); 1668 break; 1669 1670 case SCTP_CMD_HB_TIMER_UPDATE: 1671 t = cmd->obj.transport; 1672 sctp_transport_reset_hb_timer(t); 1673 break; 1674 1675 case SCTP_CMD_HB_TIMERS_STOP: 1676 sctp_cmd_hb_timers_stop(commands, asoc); 1677 break; 1678 1679 case SCTP_CMD_PROBE_TIMER_UPDATE: 1680 t = cmd->obj.transport; 1681 sctp_transport_reset_probe_timer(t); 1682 break; 1683 1684 case SCTP_CMD_REPORT_ERROR: 1685 error = cmd->obj.error; 1686 break; 1687 1688 case SCTP_CMD_PROCESS_CTSN: 1689 /* Dummy up a SACK for processing. */ 1690 sackh.cum_tsn_ack = cmd->obj.be32; 1691 sackh.a_rwnd = htonl(asoc->peer.rwnd + 1692 asoc->outqueue.outstanding_bytes); 1693 sackh.num_gap_ack_blocks = 0; 1694 sackh.num_dup_tsns = 0; 1695 chunk->subh.sack_hdr = &sackh; 1696 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, 1697 SCTP_CHUNK(chunk)); 1698 break; 1699 1700 case SCTP_CMD_DISCARD_PACKET: 1701 /* We need to discard the whole packet. 1702 * Uncork the queue since there might be 1703 * responses pending 1704 */ 1705 chunk->pdiscard = 1; 1706 if (asoc) { 1707 sctp_outq_uncork(&asoc->outqueue, gfp); 1708 local_cork = 0; 1709 } 1710 break; 1711 1712 case SCTP_CMD_RTO_PENDING: 1713 t = cmd->obj.transport; 1714 t->rto_pending = 1; 1715 break; 1716 1717 case SCTP_CMD_PART_DELIVER: 1718 asoc->stream.si->start_pd(&asoc->ulpq, GFP_ATOMIC); 1719 break; 1720 1721 case SCTP_CMD_RENEGE: 1722 asoc->stream.si->renege_events(&asoc->ulpq, 1723 cmd->obj.chunk, 1724 GFP_ATOMIC); 1725 break; 1726 1727 case SCTP_CMD_SETUP_T4: 1728 sctp_cmd_setup_t4(commands, asoc, cmd->obj.chunk); 1729 break; 1730 1731 case SCTP_CMD_PROCESS_OPERR: 1732 sctp_cmd_process_operr(commands, asoc, chunk); 1733 break; 1734 case SCTP_CMD_CLEAR_INIT_TAG: 1735 asoc->peer.i.init_tag = 0; 1736 break; 1737 case SCTP_CMD_DEL_NON_PRIMARY: 1738 sctp_cmd_del_non_primary(asoc); 1739 break; 1740 case SCTP_CMD_T3_RTX_TIMERS_STOP: 1741 sctp_cmd_t3_rtx_timers_stop(commands, asoc); 1742 break; 1743 case SCTP_CMD_FORCE_PRIM_RETRAN: 1744 t = asoc->peer.retran_path; 1745 asoc->peer.retran_path = asoc->peer.primary_path; 1746 sctp_outq_uncork(&asoc->outqueue, gfp); 1747 local_cork = 0; 1748 asoc->peer.retran_path = t; 1749 break; 1750 case SCTP_CMD_SET_SK_ERR: 1751 sctp_cmd_set_sk_err(asoc, cmd->obj.error); 1752 break; 1753 case SCTP_CMD_ASSOC_CHANGE: 1754 sctp_cmd_assoc_change(commands, asoc, 1755 cmd->obj.u8); 1756 break; 1757 case SCTP_CMD_ADAPTATION_IND: 1758 sctp_cmd_adaptation_ind(commands, asoc); 1759 break; 1760 case SCTP_CMD_PEER_NO_AUTH: 1761 sctp_cmd_peer_no_auth(commands, asoc); 1762 break; 1763 1764 case SCTP_CMD_ASSOC_SHKEY: 1765 error = sctp_auth_asoc_init_active_key(asoc, 1766 GFP_ATOMIC); 1767 break; 1768 case SCTP_CMD_UPDATE_INITTAG: 1769 asoc->peer.i.init_tag = cmd->obj.u32; 1770 break; 1771 case SCTP_CMD_SEND_MSG: 1772 if (!asoc->outqueue.cork) { 1773 sctp_outq_cork(&asoc->outqueue); 1774 local_cork = 1; 1775 } 1776 sctp_cmd_send_msg(asoc, cmd->obj.msg, gfp); 1777 break; 1778 case SCTP_CMD_PURGE_ASCONF_QUEUE: 1779 sctp_asconf_queue_teardown(asoc); 1780 break; 1781 1782 case SCTP_CMD_SET_ASOC: 1783 if (asoc && local_cork) { 1784 sctp_outq_uncork(&asoc->outqueue, gfp); 1785 local_cork = 0; 1786 } 1787 asoc = cmd->obj.asoc; 1788 break; 1789 1790 default: 1791 pr_warn("Impossible command: %u\n", 1792 cmd->verb); 1793 break; 1794 } 1795 1796 if (error) { 1797 cmd = sctp_next_cmd(commands); 1798 while (cmd) { 1799 if (cmd->verb == SCTP_CMD_REPLY) 1800 sctp_chunk_free(cmd->obj.chunk); 1801 cmd = sctp_next_cmd(commands); 1802 } 1803 break; 1804 } 1805 } 1806 1807 /* If this is in response to a received chunk, wait until 1808 * we are done with the packet to open the queue so that we don't 1809 * send multiple packets in response to a single request. 1810 */ 1811 if (asoc && SCTP_EVENT_T_CHUNK == event_type && chunk) { 1812 if (chunk->end_of_packet || chunk->singleton) 1813 sctp_outq_uncork(&asoc->outqueue, gfp); 1814 } else if (local_cork) 1815 sctp_outq_uncork(&asoc->outqueue, gfp); 1816 1817 if (sp->data_ready_signalled) 1818 sp->data_ready_signalled = 0; 1819 1820 return error; 1821 } 1822