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sm_statefuns.c
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linux-6.19.14/net/sctp/sm_statefuns.c
1// SPDX-License-Identifier: GPL-2.0-or-later 2/* SCTP kernel implementation 3 * (C) Copyright IBM Corp. 2001, 2004 4 * Copyright (c) 1999-2000 Cisco, Inc. 5 * Copyright (c) 1999-2001 Motorola, Inc. 6 * Copyright (c) 2001-2002 Intel Corp. 7 * Copyright (c) 2002 Nokia Corp. 8 * 9 * This is part of the SCTP Linux Kernel Implementation. 10 * 11 * These are the state functions for the state machine. 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 * Mathew Kotowsky <kotowsky@sctp.org> 21 * Sridhar Samudrala <samudrala@us.ibm.com> 22 * Jon Grimm <jgrimm@us.ibm.com> 23 * Hui Huang <hui.huang@nokia.com> 24 * Dajiang Zhang <dajiang.zhang@nokia.com> 25 * Daisy Chang <daisyc@us.ibm.com> 26 * Ardelle Fan <ardelle.fan@intel.com> 27 * Ryan Layer <rmlayer@us.ibm.com> 28 * Kevin Gao <kevin.gao@intel.com> 29 */ 30 31#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 32 33#include <crypto/utils.h> 34#include <linux/types.h> 35#include <linux/kernel.h> 36#include <linux/ip.h> 37#include <linux/ipv6.h> 38#include <linux/net.h> 39#include <linux/inet.h> 40#include <linux/slab.h> 41#include <net/sock.h> 42#include <net/proto_memory.h> 43#include <net/inet_ecn.h> 44#include <linux/skbuff.h> 45#include <net/sctp/sctp.h> 46#include <net/sctp/sm.h> 47#include <net/sctp/structs.h> 48 49#define CREATE_TRACE_POINTS 50#include <trace/events/sctp.h> 51 52static struct sctp_packet *sctp_abort_pkt_new( 53 struct net *net, 54 const struct sctp_endpoint *ep, 55 const struct sctp_association *asoc, 56 struct sctp_chunk *chunk, 57 const void *payload, size_t paylen); 58static int sctp_eat_data(const struct sctp_association *asoc, 59 struct sctp_chunk *chunk, 60 struct sctp_cmd_seq *commands); 61static struct sctp_packet *sctp_ootb_pkt_new( 62 struct net *net, 63 const struct sctp_association *asoc, 64 const struct sctp_chunk *chunk); 65static void sctp_send_stale_cookie_err(struct net *net, 66 const struct sctp_endpoint *ep, 67 const struct sctp_association *asoc, 68 const struct sctp_chunk *chunk, 69 struct sctp_cmd_seq *commands, 70 struct sctp_chunk *err_chunk); 71static enum sctp_disposition sctp_sf_do_5_2_6_stale( 72 struct net *net, 73 const struct sctp_endpoint *ep, 74 const struct sctp_association *asoc, 75 const union sctp_subtype type, 76 void *arg, 77 struct sctp_cmd_seq *commands); 78static enum sctp_disposition sctp_sf_shut_8_4_5( 79 struct net *net, 80 const struct sctp_endpoint *ep, 81 const struct sctp_association *asoc, 82 const union sctp_subtype type, 83 void *arg, 84 struct sctp_cmd_seq *commands); 85static enum sctp_disposition sctp_sf_tabort_8_4_8( 86 struct net *net, 87 const struct sctp_endpoint *ep, 88 const struct sctp_association *asoc, 89 const union sctp_subtype type, 90 void *arg, 91 struct sctp_cmd_seq *commands); 92static enum sctp_disposition sctp_sf_new_encap_port( 93 struct net *net, 94 const struct sctp_endpoint *ep, 95 const struct sctp_association *asoc, 96 const union sctp_subtype type, 97 void *arg, 98 struct sctp_cmd_seq *commands); 99static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk); 100 101static enum sctp_disposition sctp_stop_t1_and_abort( 102 struct net *net, 103 struct sctp_cmd_seq *commands, 104 __be16 error, int sk_err, 105 const struct sctp_association *asoc, 106 struct sctp_transport *transport); 107 108static enum sctp_disposition sctp_sf_abort_violation( 109 struct net *net, 110 const struct sctp_endpoint *ep, 111 const struct sctp_association *asoc, 112 void *arg, 113 struct sctp_cmd_seq *commands, 114 const __u8 *payload, 115 const size_t paylen); 116 117static enum sctp_disposition sctp_sf_violation_chunklen( 118 struct net *net, 119 const struct sctp_endpoint *ep, 120 const struct sctp_association *asoc, 121 const union sctp_subtype type, 122 void *arg, 123 struct sctp_cmd_seq *commands); 124 125static enum sctp_disposition sctp_sf_violation_paramlen( 126 struct net *net, 127 const struct sctp_endpoint *ep, 128 const struct sctp_association *asoc, 129 const union sctp_subtype type, 130 void *arg, void *ext, 131 struct sctp_cmd_seq *commands); 132 133static enum sctp_disposition sctp_sf_violation_ctsn( 134 struct net *net, 135 const struct sctp_endpoint *ep, 136 const struct sctp_association *asoc, 137 const union sctp_subtype type, 138 void *arg, 139 struct sctp_cmd_seq *commands); 140 141static enum sctp_disposition sctp_sf_violation_chunk( 142 struct net *net, 143 const struct sctp_endpoint *ep, 144 const struct sctp_association *asoc, 145 const union sctp_subtype type, 146 void *arg, 147 struct sctp_cmd_seq *commands); 148 149static enum sctp_ierror sctp_sf_authenticate( 150 const struct sctp_association *asoc, 151 struct sctp_chunk *chunk); 152 153static enum sctp_disposition __sctp_sf_do_9_1_abort( 154 struct net *net, 155 const struct sctp_endpoint *ep, 156 const struct sctp_association *asoc, 157 const union sctp_subtype type, 158 void *arg, 159 struct sctp_cmd_seq *commands); 160 161static enum sctp_disposition 162__sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep, 163 const struct sctp_association *asoc, 164 const union sctp_subtype type, void *arg, 165 struct sctp_cmd_seq *commands); 166 167/* Small helper function that checks if the chunk length 168 * is of the appropriate length. The 'required_length' argument 169 * is set to be the size of a specific chunk we are testing. 170 * Return Values: true = Valid length 171 * false = Invalid length 172 * 173 */ 174static inline bool sctp_chunk_length_valid(struct sctp_chunk *chunk, 175 __u16 required_length) 176{ 177 __u16 chunk_length = ntohs(chunk->chunk_hdr->length); 178 179 /* Previously already marked? */ 180 if (unlikely(chunk->pdiscard)) 181 return false; 182 if (unlikely(chunk_length < required_length)) 183 return false; 184 185 return true; 186} 187 188/* Check for format error in an ABORT chunk */ 189static inline bool sctp_err_chunk_valid(struct sctp_chunk *chunk) 190{ 191 struct sctp_errhdr *err; 192 193 sctp_walk_errors(err, chunk->chunk_hdr); 194 195 return (void *)err == (void *)chunk->chunk_end; 196} 197 198/********************************************************** 199 * These are the state functions for handling chunk events. 200 **********************************************************/ 201 202/* 203 * Process the final SHUTDOWN COMPLETE. 204 * 205 * Section: 4 (C) (diagram), 9.2 206 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify 207 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be 208 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint 209 * should stop the T2-shutdown timer and remove all knowledge of the 210 * association (and thus the association enters the CLOSED state). 211 * 212 * Verification Tag: 8.5.1(C), sctpimpguide 2.41. 213 * C) Rules for packet carrying SHUTDOWN COMPLETE: 214 * ... 215 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet 216 * if the Verification Tag field of the packet matches its own tag and 217 * the T bit is not set 218 * OR 219 * it is set to its peer's tag and the T bit is set in the Chunk 220 * Flags. 221 * Otherwise, the receiver MUST silently discard the packet 222 * and take no further action. An endpoint MUST ignore the 223 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state. 224 * 225 * Inputs 226 * (endpoint, asoc, chunk) 227 * 228 * Outputs 229 * (asoc, reply_msg, msg_up, timers, counters) 230 * 231 * The return value is the disposition of the chunk. 232 */ 233enum sctp_disposition sctp_sf_do_4_C(struct net *net, 234 const struct sctp_endpoint *ep, 235 const struct sctp_association *asoc, 236 const union sctp_subtype type, 237 void *arg, struct sctp_cmd_seq *commands) 238{ 239 struct sctp_chunk *chunk = arg; 240 struct sctp_ulpevent *ev; 241 242 if (!sctp_vtag_verify_either(chunk, asoc)) 243 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 244 245 /* RFC 2960 6.10 Bundling 246 * 247 * An endpoint MUST NOT bundle INIT, INIT ACK or 248 * SHUTDOWN COMPLETE with any other chunks. 249 */ 250 if (!chunk->singleton) 251 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 252 253 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */ 254 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 255 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 256 commands); 257 258 /* RFC 2960 10.2 SCTP-to-ULP 259 * 260 * H) SHUTDOWN COMPLETE notification 261 * 262 * When SCTP completes the shutdown procedures (section 9.2) this 263 * notification is passed to the upper layer. 264 */ 265 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 266 0, 0, 0, NULL, GFP_ATOMIC); 267 if (ev) 268 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 269 SCTP_ULPEVENT(ev)); 270 271 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint 272 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is 273 * not the chunk should be discarded. If the endpoint is in 274 * the SHUTDOWN-ACK-SENT state the endpoint should stop the 275 * T2-shutdown timer and remove all knowledge of the 276 * association (and thus the association enters the CLOSED 277 * state). 278 */ 279 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 280 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 281 282 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 283 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 284 285 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 286 SCTP_STATE(SCTP_STATE_CLOSED)); 287 288 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 289 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 290 291 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 292 293 return SCTP_DISPOSITION_DELETE_TCB; 294} 295 296/* 297 * Respond to a normal INIT chunk. 298 * We are the side that is being asked for an association. 299 * 300 * Section: 5.1 Normal Establishment of an Association, B 301 * B) "Z" shall respond immediately with an INIT ACK chunk. The 302 * destination IP address of the INIT ACK MUST be set to the source 303 * IP address of the INIT to which this INIT ACK is responding. In 304 * the response, besides filling in other parameters, "Z" must set the 305 * Verification Tag field to Tag_A, and also provide its own 306 * Verification Tag (Tag_Z) in the Initiate Tag field. 307 * 308 * Verification Tag: Must be 0. 309 * 310 * Inputs 311 * (endpoint, asoc, chunk) 312 * 313 * Outputs 314 * (asoc, reply_msg, msg_up, timers, counters) 315 * 316 * The return value is the disposition of the chunk. 317 */ 318enum sctp_disposition sctp_sf_do_5_1B_init(struct net *net, 319 const struct sctp_endpoint *ep, 320 const struct sctp_association *asoc, 321 const union sctp_subtype type, 322 void *arg, 323 struct sctp_cmd_seq *commands) 324{ 325 struct sctp_chunk *chunk = arg, *repl, *err_chunk; 326 struct sctp_unrecognized_param *unk_param; 327 struct sctp_association *new_asoc; 328 struct sctp_packet *packet; 329 int len; 330 331 /* 6.10 Bundling 332 * An endpoint MUST NOT bundle INIT, INIT ACK or 333 * SHUTDOWN COMPLETE with any other chunks. 334 * 335 * IG Section 2.11.2 336 * Furthermore, we require that the receiver of an INIT chunk MUST 337 * enforce these rules by silently discarding an arriving packet 338 * with an INIT chunk that is bundled with other chunks. 339 */ 340 if (!chunk->singleton) 341 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 342 343 /* Make sure that the INIT chunk has a valid length. 344 * Normally, this would cause an ABORT with a Protocol Violation 345 * error, but since we don't have an association, we'll 346 * just discard the packet. 347 */ 348 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk))) 349 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 350 351 /* If the packet is an OOTB packet which is temporarily on the 352 * control endpoint, respond with an ABORT. 353 */ 354 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 355 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 356 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 357 } 358 359 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 360 * Tag. 361 */ 362 if (chunk->sctp_hdr->vtag != 0) 363 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 364 365 /* If the INIT is coming toward a closing socket, we'll send back 366 * and ABORT. Essentially, this catches the race of INIT being 367 * backloged to the socket at the same time as the user issues close(). 368 * Since the socket and all its associations are going away, we 369 * can treat this OOTB 370 */ 371 if (sctp_sstate(ep->base.sk, CLOSING)) 372 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 373 374 /* Verify the INIT chunk before processing it. */ 375 err_chunk = NULL; 376 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 377 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 378 &err_chunk)) { 379 /* This chunk contains fatal error. It is to be discarded. 380 * Send an ABORT, with causes if there is any. 381 */ 382 if (err_chunk) { 383 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 384 (__u8 *)(err_chunk->chunk_hdr) + 385 sizeof(struct sctp_chunkhdr), 386 ntohs(err_chunk->chunk_hdr->length) - 387 sizeof(struct sctp_chunkhdr)); 388 389 sctp_chunk_free(err_chunk); 390 391 if (packet) { 392 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 393 SCTP_PACKET(packet)); 394 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 395 return SCTP_DISPOSITION_CONSUME; 396 } else { 397 return SCTP_DISPOSITION_NOMEM; 398 } 399 } else { 400 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 401 commands); 402 } 403 } 404 405 /* Grab the INIT header. */ 406 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 407 408 /* Tag the variable length parameters. */ 409 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 410 411 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 412 if (!new_asoc) 413 goto nomem; 414 415 /* Update socket peer label if first association. */ 416 if (security_sctp_assoc_request(new_asoc, chunk->skb)) { 417 sctp_association_free(new_asoc); 418 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 419 } 420 421 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 422 sctp_scope(sctp_source(chunk)), 423 GFP_ATOMIC) < 0) 424 goto nomem_init; 425 426 /* The call, sctp_process_init(), can fail on memory allocation. */ 427 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 428 (struct sctp_init_chunk *)chunk->chunk_hdr, 429 GFP_ATOMIC)) 430 goto nomem_init; 431 432 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 433 434 /* If there are errors need to be reported for unknown parameters, 435 * make sure to reserve enough room in the INIT ACK for them. 436 */ 437 len = 0; 438 if (err_chunk) 439 len = ntohs(err_chunk->chunk_hdr->length) - 440 sizeof(struct sctp_chunkhdr); 441 442 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 443 if (!repl) 444 goto nomem_init; 445 446 /* If there are errors need to be reported for unknown parameters, 447 * include them in the outgoing INIT ACK as "Unrecognized parameter" 448 * parameter. 449 */ 450 if (err_chunk) { 451 /* Get the "Unrecognized parameter" parameter(s) out of the 452 * ERROR chunk generated by sctp_verify_init(). Since the 453 * error cause code for "unknown parameter" and the 454 * "Unrecognized parameter" type is the same, we can 455 * construct the parameters in INIT ACK by copying the 456 * ERROR causes over. 457 */ 458 unk_param = (struct sctp_unrecognized_param *) 459 ((__u8 *)(err_chunk->chunk_hdr) + 460 sizeof(struct sctp_chunkhdr)); 461 /* Replace the cause code with the "Unrecognized parameter" 462 * parameter type. 463 */ 464 sctp_addto_chunk(repl, len, unk_param); 465 sctp_chunk_free(err_chunk); 466 } 467 468 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 469 470 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 471 472 /* 473 * Note: After sending out INIT ACK with the State Cookie parameter, 474 * "Z" MUST NOT allocate any resources, nor keep any states for the 475 * new association. Otherwise, "Z" will be vulnerable to resource 476 * attacks. 477 */ 478 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 479 480 return SCTP_DISPOSITION_DELETE_TCB; 481 482nomem_init: 483 sctp_association_free(new_asoc); 484nomem: 485 if (err_chunk) 486 sctp_chunk_free(err_chunk); 487 return SCTP_DISPOSITION_NOMEM; 488} 489 490/* 491 * Respond to a normal INIT ACK chunk. 492 * We are the side that is initiating the association. 493 * 494 * Section: 5.1 Normal Establishment of an Association, C 495 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init 496 * timer and leave COOKIE-WAIT state. "A" shall then send the State 497 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start 498 * the T1-cookie timer, and enter the COOKIE-ECHOED state. 499 * 500 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound 501 * DATA chunks, but it MUST be the first chunk in the packet and 502 * until the COOKIE ACK is returned the sender MUST NOT send any 503 * other packets to the peer. 504 * 505 * Verification Tag: 3.3.3 506 * If the value of the Initiate Tag in a received INIT ACK chunk is 507 * found to be 0, the receiver MUST treat it as an error and close the 508 * association by transmitting an ABORT. 509 * 510 * Inputs 511 * (endpoint, asoc, chunk) 512 * 513 * Outputs 514 * (asoc, reply_msg, msg_up, timers, counters) 515 * 516 * The return value is the disposition of the chunk. 517 */ 518enum sctp_disposition sctp_sf_do_5_1C_ack(struct net *net, 519 const struct sctp_endpoint *ep, 520 const struct sctp_association *asoc, 521 const union sctp_subtype type, 522 void *arg, 523 struct sctp_cmd_seq *commands) 524{ 525 struct sctp_init_chunk *initchunk; 526 struct sctp_chunk *chunk = arg; 527 struct sctp_chunk *err_chunk; 528 struct sctp_packet *packet; 529 530 if (!sctp_vtag_verify(chunk, asoc)) 531 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 532 533 /* 6.10 Bundling 534 * An endpoint MUST NOT bundle INIT, INIT ACK or 535 * SHUTDOWN COMPLETE with any other chunks. 536 */ 537 if (!chunk->singleton) 538 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 539 540 /* Make sure that the INIT-ACK chunk has a valid length */ 541 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_initack_chunk))) 542 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 543 commands); 544 /* Grab the INIT header. */ 545 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 546 547 /* Verify the INIT chunk before processing it. */ 548 err_chunk = NULL; 549 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 550 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 551 &err_chunk)) { 552 553 enum sctp_error error = SCTP_ERROR_NO_RESOURCE; 554 555 /* This chunk contains fatal error. It is to be discarded. 556 * Send an ABORT, with causes. If there are no causes, 557 * then there wasn't enough memory. Just terminate 558 * the association. 559 */ 560 if (err_chunk) { 561 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 562 (__u8 *)(err_chunk->chunk_hdr) + 563 sizeof(struct sctp_chunkhdr), 564 ntohs(err_chunk->chunk_hdr->length) - 565 sizeof(struct sctp_chunkhdr)); 566 567 sctp_chunk_free(err_chunk); 568 569 if (packet) { 570 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 571 SCTP_PACKET(packet)); 572 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 573 error = SCTP_ERROR_INV_PARAM; 574 } 575 } 576 577 /* SCTP-AUTH, Section 6.3: 578 * It should be noted that if the receiver wants to tear 579 * down an association in an authenticated way only, the 580 * handling of malformed packets should not result in 581 * tearing down the association. 582 * 583 * This means that if we only want to abort associations 584 * in an authenticated way (i.e AUTH+ABORT), then we 585 * can't destroy this association just because the packet 586 * was malformed. 587 */ 588 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 589 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 590 591 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 592 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, 593 asoc, chunk->transport); 594 } 595 596 /* Tag the variable length parameters. Note that we never 597 * convert the parameters in an INIT chunk. 598 */ 599 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 600 601 initchunk = (struct sctp_init_chunk *)chunk->chunk_hdr; 602 603 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT, 604 SCTP_PEER_INIT(initchunk)); 605 606 /* SCTP-AUTH: generate the association shared keys so that 607 * we can potentially sign the COOKIE-ECHO. 608 */ 609 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL()); 610 611 /* Reset init error count upon receipt of INIT-ACK. */ 612 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 613 614 /* 5.1 C) "A" shall stop the T1-init timer and leave 615 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie 616 * timer, and enter the COOKIE-ECHOED state. 617 */ 618 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 619 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 620 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 621 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 622 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 623 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED)); 624 625 /* 5.1 C) "A" shall then send the State Cookie received in the 626 * INIT ACK chunk in a COOKIE ECHO chunk, ... 627 */ 628 /* If there is any errors to report, send the ERROR chunk generated 629 * for unknown parameters as well. 630 */ 631 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO, 632 SCTP_CHUNK(err_chunk)); 633 634 return SCTP_DISPOSITION_CONSUME; 635} 636 637static bool sctp_auth_chunk_verify(struct net *net, struct sctp_chunk *chunk, 638 const struct sctp_association *asoc) 639{ 640 struct sctp_chunk auth; 641 642 if (!chunk->auth_chunk) 643 return true; 644 645 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo 646 * is supposed to be authenticated and we have to do delayed 647 * authentication. We've just recreated the association using 648 * the information in the cookie and now it's much easier to 649 * do the authentication. 650 */ 651 652 /* Make sure that we and the peer are AUTH capable */ 653 if (!net->sctp.auth_enable || !asoc->peer.auth_capable) 654 return false; 655 656 /* set-up our fake chunk so that we can process it */ 657 auth.skb = chunk->auth_chunk; 658 auth.asoc = chunk->asoc; 659 auth.sctp_hdr = chunk->sctp_hdr; 660 auth.chunk_hdr = (struct sctp_chunkhdr *) 661 skb_push(chunk->auth_chunk, 662 sizeof(struct sctp_chunkhdr)); 663 skb_pull(chunk->auth_chunk, sizeof(struct sctp_chunkhdr)); 664 auth.transport = chunk->transport; 665 666 return sctp_sf_authenticate(asoc, &auth) == SCTP_IERROR_NO_ERROR; 667} 668 669/* 670 * Respond to a normal COOKIE ECHO chunk. 671 * We are the side that is being asked for an association. 672 * 673 * Section: 5.1 Normal Establishment of an Association, D 674 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply 675 * with a COOKIE ACK chunk after building a TCB and moving to 676 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with 677 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK 678 * chunk MUST be the first chunk in the packet. 679 * 680 * IMPLEMENTATION NOTE: An implementation may choose to send the 681 * Communication Up notification to the SCTP user upon reception 682 * of a valid COOKIE ECHO chunk. 683 * 684 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 685 * D) Rules for packet carrying a COOKIE ECHO 686 * 687 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the 688 * Initial Tag received in the INIT ACK. 689 * 690 * - The receiver of a COOKIE ECHO follows the procedures in Section 5. 691 * 692 * Inputs 693 * (endpoint, asoc, chunk) 694 * 695 * Outputs 696 * (asoc, reply_msg, msg_up, timers, counters) 697 * 698 * The return value is the disposition of the chunk. 699 */ 700enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net, 701 const struct sctp_endpoint *ep, 702 const struct sctp_association *asoc, 703 const union sctp_subtype type, 704 void *arg, 705 struct sctp_cmd_seq *commands) 706{ 707 struct sctp_ulpevent *ev, *ai_ev = NULL, *auth_ev = NULL; 708 struct sctp_association *new_asoc; 709 struct sctp_init_chunk *peer_init; 710 struct sctp_chunk *chunk = arg; 711 struct sctp_chunk *err_chk_p; 712 struct sctp_chunk *repl; 713 struct sock *sk; 714 int error = 0; 715 716 if (asoc && !sctp_vtag_verify(chunk, asoc)) 717 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 718 719 /* If the packet is an OOTB packet which is temporarily on the 720 * control endpoint, respond with an ABORT. 721 */ 722 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 723 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 724 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 725 } 726 727 /* Make sure that the COOKIE_ECHO chunk has a valid length. 728 * In this case, we check that we have enough for at least a 729 * chunk header. More detailed verification is done 730 * in sctp_unpack_cookie(). 731 */ 732 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 733 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 734 commands); 735 736 /* If the endpoint is not listening or if the number of associations 737 * on the TCP-style socket exceed the max backlog, respond with an 738 * ABORT. 739 */ 740 sk = ep->base.sk; 741 if (!sctp_sstate(sk, LISTENING) || 742 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk))) 743 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 744 745 /* "Decode" the chunk. We have no optional parameters so we 746 * are in good shape. 747 */ 748 chunk->subh.cookie_hdr = 749 (struct sctp_signed_cookie *)chunk->skb->data; 750 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 751 sizeof(struct sctp_chunkhdr))) 752 goto nomem; 753 754 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint 755 * "Z" will reply with a COOKIE ACK chunk after building a TCB 756 * and moving to the ESTABLISHED state. 757 */ 758 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 759 &err_chk_p); 760 761 /* FIXME: 762 * If the re-build failed, what is the proper error path 763 * from here? 764 * 765 * [We should abort the association. --piggy] 766 */ 767 if (!new_asoc) { 768 /* FIXME: Several errors are possible. A bad cookie should 769 * be silently discarded, but think about logging it too. 770 */ 771 switch (error) { 772 case -SCTP_IERROR_NOMEM: 773 goto nomem; 774 775 case -SCTP_IERROR_STALE_COOKIE: 776 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 777 err_chk_p); 778 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 779 780 case -SCTP_IERROR_BAD_SIG: 781 default: 782 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 783 } 784 } 785 786 if (security_sctp_assoc_request(new_asoc, chunk->head_skb ?: chunk->skb)) { 787 sctp_association_free(new_asoc); 788 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 789 } 790 791 /* Delay state machine commands until later. 792 * 793 * Re-build the bind address for the association is done in 794 * the sctp_unpack_cookie() already. 795 */ 796 /* This is a brand-new association, so these are not yet side 797 * effects--it is safe to run them here. 798 */ 799 peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1); 800 if (!sctp_process_init(new_asoc, chunk, 801 &chunk->subh.cookie_hdr->c.peer_addr, 802 peer_init, GFP_ATOMIC)) 803 goto nomem_init; 804 805 /* SCTP-AUTH: Now that we've populate required fields in 806 * sctp_process_init, set up the association shared keys as 807 * necessary so that we can potentially authenticate the ACK 808 */ 809 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC); 810 if (error) 811 goto nomem_init; 812 813 if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) { 814 sctp_association_free(new_asoc); 815 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 816 } 817 818 repl = sctp_make_cookie_ack(new_asoc, chunk); 819 if (!repl) 820 goto nomem_init; 821 822 /* RFC 2960 5.1 Normal Establishment of an Association 823 * 824 * D) IMPLEMENTATION NOTE: An implementation may choose to 825 * send the Communication Up notification to the SCTP user 826 * upon reception of a valid COOKIE ECHO chunk. 827 */ 828 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0, 829 new_asoc->c.sinit_num_ostreams, 830 new_asoc->c.sinit_max_instreams, 831 NULL, GFP_ATOMIC); 832 if (!ev) 833 goto nomem_ev; 834 835 /* Sockets API Draft Section 5.3.1.6 836 * When a peer sends a Adaptation Layer Indication parameter , SCTP 837 * delivers this notification to inform the application that of the 838 * peers requested adaptation layer. 839 */ 840 if (new_asoc->peer.adaptation_ind) { 841 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc, 842 GFP_ATOMIC); 843 if (!ai_ev) 844 goto nomem_aiev; 845 } 846 847 if (!new_asoc->peer.auth_capable) { 848 auth_ev = sctp_ulpevent_make_authkey(new_asoc, 0, 849 SCTP_AUTH_NO_AUTH, 850 GFP_ATOMIC); 851 if (!auth_ev) 852 goto nomem_authev; 853 } 854 855 /* Add all the state machine commands now since we've created 856 * everything. This way we don't introduce memory corruptions 857 * during side-effect processing and correctly count established 858 * associations. 859 */ 860 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 861 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 862 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 863 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 864 SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS); 865 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 866 867 if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 868 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 869 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 870 871 /* This will send the COOKIE ACK */ 872 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 873 874 /* Queue the ASSOC_CHANGE event */ 875 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 876 877 /* Send up the Adaptation Layer Indication event */ 878 if (ai_ev) 879 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 880 SCTP_ULPEVENT(ai_ev)); 881 882 if (auth_ev) 883 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 884 SCTP_ULPEVENT(auth_ev)); 885 886 return SCTP_DISPOSITION_CONSUME; 887 888nomem_authev: 889 if (ai_ev) 890 sctp_ulpevent_free(ai_ev); 891nomem_aiev: 892 sctp_ulpevent_free(ev); 893nomem_ev: 894 sctp_chunk_free(repl); 895nomem_init: 896 sctp_association_free(new_asoc); 897nomem: 898 return SCTP_DISPOSITION_NOMEM; 899} 900 901/* 902 * Respond to a normal COOKIE ACK chunk. 903 * We are the side that is asking for an association. 904 * 905 * RFC 2960 5.1 Normal Establishment of an Association 906 * 907 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the 908 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie 909 * timer. It may also notify its ULP about the successful 910 * establishment of the association with a Communication Up 911 * notification (see Section 10). 912 * 913 * Verification Tag: 914 * Inputs 915 * (endpoint, asoc, chunk) 916 * 917 * Outputs 918 * (asoc, reply_msg, msg_up, timers, counters) 919 * 920 * The return value is the disposition of the chunk. 921 */ 922enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net, 923 const struct sctp_endpoint *ep, 924 const struct sctp_association *asoc, 925 const union sctp_subtype type, 926 void *arg, 927 struct sctp_cmd_seq *commands) 928{ 929 struct sctp_chunk *chunk = arg; 930 struct sctp_ulpevent *ev; 931 932 if (!sctp_vtag_verify(chunk, asoc)) 933 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 934 935 /* Set peer label for connection. */ 936 if (security_sctp_assoc_established((struct sctp_association *)asoc, 937 chunk->head_skb ?: chunk->skb)) 938 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 939 940 /* Verify that the chunk length for the COOKIE-ACK is OK. 941 * If we don't do this, any bundled chunks may be junked. 942 */ 943 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 944 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 945 commands); 946 947 /* Reset init error count upon receipt of COOKIE-ACK, 948 * to avoid problems with the management of this 949 * counter in stale cookie situations when a transition back 950 * from the COOKIE-ECHOED state to the COOKIE-WAIT 951 * state is performed. 952 */ 953 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 954 955 /* RFC 2960 5.1 Normal Establishment of an Association 956 * 957 * E) Upon reception of the COOKIE ACK, endpoint "A" will move 958 * from the COOKIE-ECHOED state to the ESTABLISHED state, 959 * stopping the T1-cookie timer. 960 */ 961 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 962 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 963 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 964 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 965 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 966 SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS); 967 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 968 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 969 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 970 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 971 972 /* It may also notify its ULP about the successful 973 * establishment of the association with a Communication Up 974 * notification (see Section 10). 975 */ 976 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 977 0, asoc->c.sinit_num_ostreams, 978 asoc->c.sinit_max_instreams, 979 NULL, GFP_ATOMIC); 980 981 if (!ev) 982 goto nomem; 983 984 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 985 986 /* Sockets API Draft Section 5.3.1.6 987 * When a peer sends a Adaptation Layer Indication parameter , SCTP 988 * delivers this notification to inform the application that of the 989 * peers requested adaptation layer. 990 */ 991 if (asoc->peer.adaptation_ind) { 992 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC); 993 if (!ev) 994 goto nomem; 995 996 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 997 SCTP_ULPEVENT(ev)); 998 } 999 1000 if (!asoc->peer.auth_capable) { 1001 ev = sctp_ulpevent_make_authkey(asoc, 0, SCTP_AUTH_NO_AUTH, 1002 GFP_ATOMIC); 1003 if (!ev) 1004 goto nomem; 1005 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1006 SCTP_ULPEVENT(ev)); 1007 } 1008 1009 return SCTP_DISPOSITION_CONSUME; 1010nomem: 1011 return SCTP_DISPOSITION_NOMEM; 1012} 1013 1014/* Generate and sendout a heartbeat packet. */ 1015static enum sctp_disposition sctp_sf_heartbeat( 1016 const struct sctp_endpoint *ep, 1017 const struct sctp_association *asoc, 1018 const union sctp_subtype type, 1019 void *arg, 1020 struct sctp_cmd_seq *commands) 1021{ 1022 struct sctp_transport *transport = (struct sctp_transport *) arg; 1023 struct sctp_chunk *reply; 1024 1025 /* Send a heartbeat to our peer. */ 1026 reply = sctp_make_heartbeat(asoc, transport, 0); 1027 if (!reply) 1028 return SCTP_DISPOSITION_NOMEM; 1029 1030 /* Set rto_pending indicating that an RTT measurement 1031 * is started with this heartbeat chunk. 1032 */ 1033 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING, 1034 SCTP_TRANSPORT(transport)); 1035 1036 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1037 return SCTP_DISPOSITION_CONSUME; 1038} 1039 1040/* Generate a HEARTBEAT packet on the given transport. */ 1041enum sctp_disposition sctp_sf_sendbeat_8_3(struct net *net, 1042 const struct sctp_endpoint *ep, 1043 const struct sctp_association *asoc, 1044 const union sctp_subtype type, 1045 void *arg, 1046 struct sctp_cmd_seq *commands) 1047{ 1048 struct sctp_transport *transport = (struct sctp_transport *) arg; 1049 1050 if (asoc->overall_error_count >= asoc->max_retrans) { 1051 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 1052 SCTP_ERROR(ETIMEDOUT)); 1053 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 1054 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 1055 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 1056 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 1057 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 1058 return SCTP_DISPOSITION_DELETE_TCB; 1059 } 1060 1061 /* Section 3.3.5. 1062 * The Sender-specific Heartbeat Info field should normally include 1063 * information about the sender's current time when this HEARTBEAT 1064 * chunk is sent and the destination transport address to which this 1065 * HEARTBEAT is sent (see Section 8.3). 1066 */ 1067 1068 if (transport->param_flags & SPP_HB_ENABLE) { 1069 if (SCTP_DISPOSITION_NOMEM == 1070 sctp_sf_heartbeat(ep, asoc, type, arg, 1071 commands)) 1072 return SCTP_DISPOSITION_NOMEM; 1073 1074 /* Set transport error counter and association error counter 1075 * when sending heartbeat. 1076 */ 1077 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 1078 SCTP_TRANSPORT(transport)); 1079 } 1080 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE, 1081 SCTP_TRANSPORT(transport)); 1082 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE, 1083 SCTP_TRANSPORT(transport)); 1084 1085 return SCTP_DISPOSITION_CONSUME; 1086} 1087 1088/* resend asoc strreset_chunk. */ 1089enum sctp_disposition sctp_sf_send_reconf(struct net *net, 1090 const struct sctp_endpoint *ep, 1091 const struct sctp_association *asoc, 1092 const union sctp_subtype type, 1093 void *arg, 1094 struct sctp_cmd_seq *commands) 1095{ 1096 struct sctp_transport *transport = arg; 1097 1098 if (asoc->overall_error_count >= asoc->max_retrans) { 1099 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 1100 SCTP_ERROR(ETIMEDOUT)); 1101 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 1102 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 1103 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 1104 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 1105 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 1106 return SCTP_DISPOSITION_DELETE_TCB; 1107 } 1108 1109 sctp_chunk_hold(asoc->strreset_chunk); 1110 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1111 SCTP_CHUNK(asoc->strreset_chunk)); 1112 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 1113 1114 return SCTP_DISPOSITION_CONSUME; 1115} 1116 1117/* send hb chunk with padding for PLPMUTD. */ 1118enum sctp_disposition sctp_sf_send_probe(struct net *net, 1119 const struct sctp_endpoint *ep, 1120 const struct sctp_association *asoc, 1121 const union sctp_subtype type, 1122 void *arg, 1123 struct sctp_cmd_seq *commands) 1124{ 1125 struct sctp_transport *transport = (struct sctp_transport *)arg; 1126 struct sctp_chunk *reply; 1127 1128 if (!sctp_transport_pl_enabled(transport)) 1129 return SCTP_DISPOSITION_CONSUME; 1130 1131 sctp_transport_pl_send(transport); 1132 reply = sctp_make_heartbeat(asoc, transport, transport->pl.probe_size); 1133 if (!reply) 1134 return SCTP_DISPOSITION_NOMEM; 1135 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1136 sctp_add_cmd_sf(commands, SCTP_CMD_PROBE_TIMER_UPDATE, 1137 SCTP_TRANSPORT(transport)); 1138 1139 return SCTP_DISPOSITION_CONSUME; 1140} 1141 1142/* 1143 * Process an heartbeat request. 1144 * 1145 * Section: 8.3 Path Heartbeat 1146 * The receiver of the HEARTBEAT should immediately respond with a 1147 * HEARTBEAT ACK that contains the Heartbeat Information field copied 1148 * from the received HEARTBEAT chunk. 1149 * 1150 * Verification Tag: 8.5 Verification Tag [Normal verification] 1151 * When receiving an SCTP packet, the endpoint MUST ensure that the 1152 * value in the Verification Tag field of the received SCTP packet 1153 * matches its own Tag. If the received Verification Tag value does not 1154 * match the receiver's own tag value, the receiver shall silently 1155 * discard the packet and shall not process it any further except for 1156 * those cases listed in Section 8.5.1 below. 1157 * 1158 * Inputs 1159 * (endpoint, asoc, chunk) 1160 * 1161 * Outputs 1162 * (asoc, reply_msg, msg_up, timers, counters) 1163 * 1164 * The return value is the disposition of the chunk. 1165 */ 1166enum sctp_disposition sctp_sf_beat_8_3(struct net *net, 1167 const struct sctp_endpoint *ep, 1168 const struct sctp_association *asoc, 1169 const union sctp_subtype type, 1170 void *arg, struct sctp_cmd_seq *commands) 1171{ 1172 struct sctp_paramhdr *param_hdr; 1173 struct sctp_chunk *chunk = arg; 1174 struct sctp_chunk *reply; 1175 size_t paylen = 0; 1176 1177 if (!sctp_vtag_verify(chunk, asoc)) 1178 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1179 1180 /* Make sure that the HEARTBEAT chunk has a valid length. */ 1181 if (!sctp_chunk_length_valid(chunk, 1182 sizeof(struct sctp_heartbeat_chunk))) 1183 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1184 commands); 1185 1186 /* 8.3 The receiver of the HEARTBEAT should immediately 1187 * respond with a HEARTBEAT ACK that contains the Heartbeat 1188 * Information field copied from the received HEARTBEAT chunk. 1189 */ 1190 chunk->subh.hb_hdr = (struct sctp_heartbeathdr *)chunk->skb->data; 1191 param_hdr = (struct sctp_paramhdr *)chunk->subh.hb_hdr; 1192 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(struct sctp_chunkhdr); 1193 1194 if (ntohs(param_hdr->length) > paylen) 1195 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 1196 param_hdr, commands); 1197 1198 if (!pskb_pull(chunk->skb, paylen)) 1199 goto nomem; 1200 1201 reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen); 1202 if (!reply) 1203 goto nomem; 1204 1205 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1206 return SCTP_DISPOSITION_CONSUME; 1207 1208nomem: 1209 return SCTP_DISPOSITION_NOMEM; 1210} 1211 1212/* 1213 * Process the returning HEARTBEAT ACK. 1214 * 1215 * Section: 8.3 Path Heartbeat 1216 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT 1217 * should clear the error counter of the destination transport 1218 * address to which the HEARTBEAT was sent, and mark the destination 1219 * transport address as active if it is not so marked. The endpoint may 1220 * optionally report to the upper layer when an inactive destination 1221 * address is marked as active due to the reception of the latest 1222 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also 1223 * clear the association overall error count as well (as defined 1224 * in section 8.1). 1225 * 1226 * The receiver of the HEARTBEAT ACK should also perform an RTT 1227 * measurement for that destination transport address using the time 1228 * value carried in the HEARTBEAT ACK chunk. 1229 * 1230 * Verification Tag: 8.5 Verification Tag [Normal verification] 1231 * 1232 * Inputs 1233 * (endpoint, asoc, chunk) 1234 * 1235 * Outputs 1236 * (asoc, reply_msg, msg_up, timers, counters) 1237 * 1238 * The return value is the disposition of the chunk. 1239 */ 1240enum sctp_disposition sctp_sf_backbeat_8_3(struct net *net, 1241 const struct sctp_endpoint *ep, 1242 const struct sctp_association *asoc, 1243 const union sctp_subtype type, 1244 void *arg, 1245 struct sctp_cmd_seq *commands) 1246{ 1247 struct sctp_sender_hb_info *hbinfo; 1248 struct sctp_chunk *chunk = arg; 1249 struct sctp_transport *link; 1250 unsigned long max_interval; 1251 union sctp_addr from_addr; 1252 1253 if (!sctp_vtag_verify(chunk, asoc)) 1254 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1255 1256 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */ 1257 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr) + 1258 sizeof(*hbinfo))) 1259 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1260 commands); 1261 1262 hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data; 1263 /* Make sure that the length of the parameter is what we expect */ 1264 if (ntohs(hbinfo->param_hdr.length) != sizeof(*hbinfo)) 1265 return SCTP_DISPOSITION_DISCARD; 1266 1267 from_addr = hbinfo->daddr; 1268 link = sctp_assoc_lookup_paddr(asoc, &from_addr); 1269 1270 /* This should never happen, but lets log it if so. */ 1271 if (unlikely(!link)) { 1272 if (from_addr.sa.sa_family == AF_INET6) { 1273 net_warn_ratelimited("%s association %p could not find address %pI6\n", 1274 __func__, 1275 asoc, 1276 &from_addr.v6.sin6_addr); 1277 } else { 1278 net_warn_ratelimited("%s association %p could not find address %pI4\n", 1279 __func__, 1280 asoc, 1281 &from_addr.v4.sin_addr.s_addr); 1282 } 1283 return SCTP_DISPOSITION_DISCARD; 1284 } 1285 1286 /* Validate the 64-bit random nonce. */ 1287 if (hbinfo->hb_nonce != link->hb_nonce) 1288 return SCTP_DISPOSITION_DISCARD; 1289 1290 if (hbinfo->probe_size) { 1291 if (hbinfo->probe_size != link->pl.probe_size || 1292 !sctp_transport_pl_enabled(link)) 1293 return SCTP_DISPOSITION_DISCARD; 1294 1295 if (sctp_transport_pl_recv(link)) 1296 return SCTP_DISPOSITION_CONSUME; 1297 1298 return sctp_sf_send_probe(net, ep, asoc, type, link, commands); 1299 } 1300 1301 max_interval = link->hbinterval + link->rto; 1302 1303 /* Check if the timestamp looks valid. */ 1304 if (time_after(hbinfo->sent_at, jiffies) || 1305 time_after(jiffies, hbinfo->sent_at + max_interval)) { 1306 pr_debug("%s: HEARTBEAT ACK with invalid timestamp received " 1307 "for transport:%p\n", __func__, link); 1308 1309 return SCTP_DISPOSITION_DISCARD; 1310 } 1311 1312 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of 1313 * the HEARTBEAT should clear the error counter of the 1314 * destination transport address to which the HEARTBEAT was 1315 * sent and mark the destination transport address as active if 1316 * it is not so marked. 1317 */ 1318 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); 1319 1320 return SCTP_DISPOSITION_CONSUME; 1321} 1322 1323/* Helper function to send out an abort for the restart 1324 * condition. 1325 */ 1326static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa, 1327 struct sctp_chunk *init, 1328 struct sctp_cmd_seq *commands) 1329{ 1330 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); 1331 union sctp_addr_param *addrparm; 1332 struct sctp_errhdr *errhdr; 1333 char buffer[sizeof(*errhdr) + sizeof(*addrparm)]; 1334 struct sctp_endpoint *ep; 1335 struct sctp_packet *pkt; 1336 int len; 1337 1338 /* Build the error on the stack. We are way to malloc crazy 1339 * throughout the code today. 1340 */ 1341 errhdr = (struct sctp_errhdr *)buffer; 1342 addrparm = (union sctp_addr_param *)(errhdr + 1); 1343 1344 /* Copy into a parm format. */ 1345 len = af->to_addr_param(ssa, addrparm); 1346 len += sizeof(*errhdr); 1347 1348 errhdr->cause = SCTP_ERROR_RESTART; 1349 errhdr->length = htons(len); 1350 1351 /* Assign to the control socket. */ 1352 ep = sctp_sk(net->sctp.ctl_sock)->ep; 1353 1354 /* Association is NULL since this may be a restart attack and we 1355 * want to send back the attacker's vtag. 1356 */ 1357 pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len); 1358 1359 if (!pkt) 1360 goto out; 1361 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); 1362 1363 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1364 1365 /* Discard the rest of the inbound packet. */ 1366 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 1367 1368out: 1369 /* Even if there is no memory, treat as a failure so 1370 * the packet will get dropped. 1371 */ 1372 return 0; 1373} 1374 1375static bool list_has_sctp_addr(const struct list_head *list, 1376 union sctp_addr *ipaddr) 1377{ 1378 struct sctp_transport *addr; 1379 1380 list_for_each_entry(addr, list, transports) { 1381 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr)) 1382 return true; 1383 } 1384 1385 return false; 1386} 1387/* A restart is occurring, check to make sure no new addresses 1388 * are being added as we may be under a takeover attack. 1389 */ 1390static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, 1391 const struct sctp_association *asoc, 1392 struct sctp_chunk *init, 1393 struct sctp_cmd_seq *commands) 1394{ 1395 struct net *net = new_asoc->base.net; 1396 struct sctp_transport *new_addr; 1397 int ret = 1; 1398 1399 /* Implementor's Guide - Section 5.2.2 1400 * ... 1401 * Before responding the endpoint MUST check to see if the 1402 * unexpected INIT adds new addresses to the association. If new 1403 * addresses are added to the association, the endpoint MUST respond 1404 * with an ABORT.. 1405 */ 1406 1407 /* Search through all current addresses and make sure 1408 * we aren't adding any new ones. 1409 */ 1410 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list, 1411 transports) { 1412 if (!list_has_sctp_addr(&asoc->peer.transport_addr_list, 1413 &new_addr->ipaddr)) { 1414 sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init, 1415 commands); 1416 ret = 0; 1417 break; 1418 } 1419 } 1420 1421 /* Return success if all addresses were found. */ 1422 return ret; 1423} 1424 1425/* Populate the verification/tie tags based on overlapping INIT 1426 * scenario. 1427 * 1428 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. 1429 */ 1430static void sctp_tietags_populate(struct sctp_association *new_asoc, 1431 const struct sctp_association *asoc) 1432{ 1433 switch (asoc->state) { 1434 1435 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ 1436 1437 case SCTP_STATE_COOKIE_WAIT: 1438 new_asoc->c.my_vtag = asoc->c.my_vtag; 1439 new_asoc->c.my_ttag = asoc->c.my_vtag; 1440 new_asoc->c.peer_ttag = 0; 1441 break; 1442 1443 case SCTP_STATE_COOKIE_ECHOED: 1444 new_asoc->c.my_vtag = asoc->c.my_vtag; 1445 new_asoc->c.my_ttag = asoc->c.my_vtag; 1446 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1447 break; 1448 1449 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, 1450 * COOKIE-WAIT and SHUTDOWN-ACK-SENT 1451 */ 1452 default: 1453 new_asoc->c.my_ttag = asoc->c.my_vtag; 1454 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1455 break; 1456 } 1457 1458 /* Other parameters for the endpoint SHOULD be copied from the 1459 * existing parameters of the association (e.g. number of 1460 * outbound streams) into the INIT ACK and cookie. 1461 */ 1462 new_asoc->rwnd = asoc->rwnd; 1463 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; 1464 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; 1465 new_asoc->c.initial_tsn = asoc->c.initial_tsn; 1466} 1467 1468/* 1469 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO 1470 * handling action. 1471 * 1472 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. 1473 * 1474 * Returns value representing action to be taken. These action values 1475 * correspond to Action/Description values in RFC 2960, Table 2. 1476 */ 1477static char sctp_tietags_compare(struct sctp_association *new_asoc, 1478 const struct sctp_association *asoc) 1479{ 1480 /* In this case, the peer may have restarted. */ 1481 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1482 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && 1483 (asoc->c.my_vtag == new_asoc->c.my_ttag) && 1484 (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) 1485 return 'A'; 1486 1487 /* Collision case B. */ 1488 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1489 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || 1490 (0 == asoc->c.peer_vtag))) { 1491 return 'B'; 1492 } 1493 1494 /* Collision case D. */ 1495 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1496 (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) 1497 return 'D'; 1498 1499 /* Collision case C. */ 1500 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1501 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && 1502 (0 == new_asoc->c.my_ttag) && 1503 (0 == new_asoc->c.peer_ttag)) 1504 return 'C'; 1505 1506 /* No match to any of the special cases; discard this packet. */ 1507 return 'E'; 1508} 1509 1510/* Common helper routine for both duplicate and simultaneous INIT 1511 * chunk handling. 1512 */ 1513static enum sctp_disposition sctp_sf_do_unexpected_init( 1514 struct net *net, 1515 const struct sctp_endpoint *ep, 1516 const struct sctp_association *asoc, 1517 const union sctp_subtype type, 1518 void *arg, 1519 struct sctp_cmd_seq *commands) 1520{ 1521 struct sctp_chunk *chunk = arg, *repl, *err_chunk; 1522 struct sctp_unrecognized_param *unk_param; 1523 struct sctp_association *new_asoc; 1524 enum sctp_disposition retval; 1525 struct sctp_packet *packet; 1526 int len; 1527 1528 /* 6.10 Bundling 1529 * An endpoint MUST NOT bundle INIT, INIT ACK or 1530 * SHUTDOWN COMPLETE with any other chunks. 1531 * 1532 * IG Section 2.11.2 1533 * Furthermore, we require that the receiver of an INIT chunk MUST 1534 * enforce these rules by silently discarding an arriving packet 1535 * with an INIT chunk that is bundled with other chunks. 1536 */ 1537 if (!chunk->singleton) 1538 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1539 1540 /* Make sure that the INIT chunk has a valid length. */ 1541 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk))) 1542 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1543 1544 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 1545 * Tag. 1546 */ 1547 if (chunk->sctp_hdr->vtag != 0) 1548 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 1549 1550 if (SCTP_INPUT_CB(chunk->skb)->encap_port != chunk->transport->encap_port) 1551 return sctp_sf_new_encap_port(net, ep, asoc, type, arg, commands); 1552 1553 /* Grab the INIT header. */ 1554 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 1555 1556 /* Tag the variable length parameters. */ 1557 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 1558 1559 /* Verify the INIT chunk before processing it. */ 1560 err_chunk = NULL; 1561 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 1562 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 1563 &err_chunk)) { 1564 /* This chunk contains fatal error. It is to be discarded. 1565 * Send an ABORT, with causes if there is any. 1566 */ 1567 if (err_chunk) { 1568 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 1569 (__u8 *)(err_chunk->chunk_hdr) + 1570 sizeof(struct sctp_chunkhdr), 1571 ntohs(err_chunk->chunk_hdr->length) - 1572 sizeof(struct sctp_chunkhdr)); 1573 1574 if (packet) { 1575 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 1576 SCTP_PACKET(packet)); 1577 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1578 retval = SCTP_DISPOSITION_CONSUME; 1579 } else { 1580 retval = SCTP_DISPOSITION_NOMEM; 1581 } 1582 goto cleanup; 1583 } else { 1584 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 1585 commands); 1586 } 1587 } 1588 1589 /* 1590 * Other parameters for the endpoint SHOULD be copied from the 1591 * existing parameters of the association (e.g. number of 1592 * outbound streams) into the INIT ACK and cookie. 1593 * FIXME: We are copying parameters from the endpoint not the 1594 * association. 1595 */ 1596 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 1597 if (!new_asoc) 1598 goto nomem; 1599 1600 /* Update socket peer label if first association. */ 1601 if (security_sctp_assoc_request(new_asoc, chunk->skb)) { 1602 sctp_association_free(new_asoc); 1603 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1604 } 1605 1606 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 1607 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0) 1608 goto nomem; 1609 1610 /* In the outbound INIT ACK the endpoint MUST copy its current 1611 * Verification Tag and Peers Verification tag into a reserved 1612 * place (local tie-tag and per tie-tag) within the state cookie. 1613 */ 1614 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 1615 (struct sctp_init_chunk *)chunk->chunk_hdr, 1616 GFP_ATOMIC)) 1617 goto nomem; 1618 1619 /* Make sure no new addresses are being added during the 1620 * restart. Do not do this check for COOKIE-WAIT state, 1621 * since there are no peer addresses to check against. 1622 * Upon return an ABORT will have been sent if needed. 1623 */ 1624 if (!sctp_state(asoc, COOKIE_WAIT)) { 1625 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, 1626 commands)) { 1627 retval = SCTP_DISPOSITION_CONSUME; 1628 goto nomem_retval; 1629 } 1630 } 1631 1632 sctp_tietags_populate(new_asoc, asoc); 1633 1634 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 1635 1636 /* If there are errors need to be reported for unknown parameters, 1637 * make sure to reserve enough room in the INIT ACK for them. 1638 */ 1639 len = 0; 1640 if (err_chunk) { 1641 len = ntohs(err_chunk->chunk_hdr->length) - 1642 sizeof(struct sctp_chunkhdr); 1643 } 1644 1645 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 1646 if (!repl) 1647 goto nomem; 1648 1649 /* If there are errors need to be reported for unknown parameters, 1650 * include them in the outgoing INIT ACK as "Unrecognized parameter" 1651 * parameter. 1652 */ 1653 if (err_chunk) { 1654 /* Get the "Unrecognized parameter" parameter(s) out of the 1655 * ERROR chunk generated by sctp_verify_init(). Since the 1656 * error cause code for "unknown parameter" and the 1657 * "Unrecognized parameter" type is the same, we can 1658 * construct the parameters in INIT ACK by copying the 1659 * ERROR causes over. 1660 */ 1661 unk_param = (struct sctp_unrecognized_param *) 1662 ((__u8 *)(err_chunk->chunk_hdr) + 1663 sizeof(struct sctp_chunkhdr)); 1664 /* Replace the cause code with the "Unrecognized parameter" 1665 * parameter type. 1666 */ 1667 sctp_addto_chunk(repl, len, unk_param); 1668 } 1669 1670 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1671 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1672 1673 /* 1674 * Note: After sending out INIT ACK with the State Cookie parameter, 1675 * "Z" MUST NOT allocate any resources for this new association. 1676 * Otherwise, "Z" will be vulnerable to resource attacks. 1677 */ 1678 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1679 retval = SCTP_DISPOSITION_CONSUME; 1680 1681 return retval; 1682 1683nomem: 1684 retval = SCTP_DISPOSITION_NOMEM; 1685nomem_retval: 1686 if (new_asoc) 1687 sctp_association_free(new_asoc); 1688cleanup: 1689 if (err_chunk) 1690 sctp_chunk_free(err_chunk); 1691 return retval; 1692} 1693 1694/* 1695 * Handle simultaneous INIT. 1696 * This means we started an INIT and then we got an INIT request from 1697 * our peer. 1698 * 1699 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) 1700 * This usually indicates an initialization collision, i.e., each 1701 * endpoint is attempting, at about the same time, to establish an 1702 * association with the other endpoint. 1703 * 1704 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an 1705 * endpoint MUST respond with an INIT ACK using the same parameters it 1706 * sent in its original INIT chunk (including its Verification Tag, 1707 * unchanged). These original parameters are combined with those from the 1708 * newly received INIT chunk. The endpoint shall also generate a State 1709 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its 1710 * INIT to calculate the State Cookie. 1711 * 1712 * After that, the endpoint MUST NOT change its state, the T1-init 1713 * timer shall be left running and the corresponding TCB MUST NOT be 1714 * destroyed. The normal procedures for handling State Cookies when 1715 * a TCB exists will resolve the duplicate INITs to a single association. 1716 * 1717 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate 1718 * its Tie-Tags with the Tag information of itself and its peer (see 1719 * section 5.2.2 for a description of the Tie-Tags). 1720 * 1721 * Verification Tag: Not explicit, but an INIT can not have a valid 1722 * verification tag, so we skip the check. 1723 * 1724 * Inputs 1725 * (endpoint, asoc, chunk) 1726 * 1727 * Outputs 1728 * (asoc, reply_msg, msg_up, timers, counters) 1729 * 1730 * The return value is the disposition of the chunk. 1731 */ 1732enum sctp_disposition sctp_sf_do_5_2_1_siminit( 1733 struct net *net, 1734 const struct sctp_endpoint *ep, 1735 const struct sctp_association *asoc, 1736 const union sctp_subtype type, 1737 void *arg, 1738 struct sctp_cmd_seq *commands) 1739{ 1740 /* Call helper to do the real work for both simultaneous and 1741 * duplicate INIT chunk handling. 1742 */ 1743 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1744} 1745 1746/* 1747 * Handle duplicated INIT messages. These are usually delayed 1748 * restransmissions. 1749 * 1750 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, 1751 * COOKIE-ECHOED and COOKIE-WAIT 1752 * 1753 * Unless otherwise stated, upon reception of an unexpected INIT for 1754 * this association, the endpoint shall generate an INIT ACK with a 1755 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its 1756 * current Verification Tag and peer's Verification Tag into a reserved 1757 * place within the state cookie. We shall refer to these locations as 1758 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet 1759 * containing this INIT ACK MUST carry a Verification Tag value equal to 1760 * the Initiation Tag found in the unexpected INIT. And the INIT ACK 1761 * MUST contain a new Initiation Tag (randomly generated see Section 1762 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the 1763 * existing parameters of the association (e.g. number of outbound 1764 * streams) into the INIT ACK and cookie. 1765 * 1766 * After sending out the INIT ACK, the endpoint shall take no further 1767 * actions, i.e., the existing association, including its current state, 1768 * and the corresponding TCB MUST NOT be changed. 1769 * 1770 * Note: Only when a TCB exists and the association is not in a COOKIE- 1771 * WAIT state are the Tie-Tags populated. For a normal association INIT 1772 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be 1773 * set to 0 (indicating that no previous TCB existed). The INIT ACK and 1774 * State Cookie are populated as specified in section 5.2.1. 1775 * 1776 * Verification Tag: Not specified, but an INIT has no way of knowing 1777 * what the verification tag could be, so we ignore it. 1778 * 1779 * Inputs 1780 * (endpoint, asoc, chunk) 1781 * 1782 * Outputs 1783 * (asoc, reply_msg, msg_up, timers, counters) 1784 * 1785 * The return value is the disposition of the chunk. 1786 */ 1787enum sctp_disposition sctp_sf_do_5_2_2_dupinit( 1788 struct net *net, 1789 const struct sctp_endpoint *ep, 1790 const struct sctp_association *asoc, 1791 const union sctp_subtype type, 1792 void *arg, 1793 struct sctp_cmd_seq *commands) 1794{ 1795 /* Call helper to do the real work for both simultaneous and 1796 * duplicate INIT chunk handling. 1797 */ 1798 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1799} 1800 1801 1802/* 1803 * Unexpected INIT-ACK handler. 1804 * 1805 * Section 5.2.3 1806 * If an INIT ACK received by an endpoint in any state other than the 1807 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk. 1808 * An unexpected INIT ACK usually indicates the processing of an old or 1809 * duplicated INIT chunk. 1810*/ 1811enum sctp_disposition sctp_sf_do_5_2_3_initack( 1812 struct net *net, 1813 const struct sctp_endpoint *ep, 1814 const struct sctp_association *asoc, 1815 const union sctp_subtype type, 1816 void *arg, 1817 struct sctp_cmd_seq *commands) 1818{ 1819 /* Per the above section, we'll discard the chunk if we have an 1820 * endpoint. If this is an OOTB INIT-ACK, treat it as such. 1821 */ 1822 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) 1823 return sctp_sf_ootb(net, ep, asoc, type, arg, commands); 1824 else 1825 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 1826} 1827 1828static int sctp_sf_do_assoc_update(struct sctp_association *asoc, 1829 struct sctp_association *new, 1830 struct sctp_cmd_seq *cmds) 1831{ 1832 struct net *net = asoc->base.net; 1833 struct sctp_chunk *abort; 1834 1835 if (!sctp_assoc_update(asoc, new)) 1836 return 0; 1837 1838 abort = sctp_make_abort(asoc, NULL, sizeof(struct sctp_errhdr)); 1839 if (abort) { 1840 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 1841 sctp_add_cmd_sf(cmds, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 1842 } 1843 sctp_add_cmd_sf(cmds, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNABORTED)); 1844 sctp_add_cmd_sf(cmds, SCTP_CMD_ASSOC_FAILED, 1845 SCTP_PERR(SCTP_ERROR_RSRC_LOW)); 1846 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 1847 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 1848 1849 return -ENOMEM; 1850} 1851 1852/* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') 1853 * 1854 * Section 5.2.4 1855 * A) In this case, the peer may have restarted. 1856 */ 1857static enum sctp_disposition sctp_sf_do_dupcook_a( 1858 struct net *net, 1859 const struct sctp_endpoint *ep, 1860 const struct sctp_association *asoc, 1861 struct sctp_chunk *chunk, 1862 struct sctp_cmd_seq *commands, 1863 struct sctp_association *new_asoc) 1864{ 1865 struct sctp_init_chunk *peer_init; 1866 enum sctp_disposition disposition; 1867 struct sctp_ulpevent *ev; 1868 struct sctp_chunk *repl; 1869 struct sctp_chunk *err; 1870 1871 /* new_asoc is a brand-new association, so these are not yet 1872 * side effects--it is safe to run them here. 1873 */ 1874 peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1); 1875 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1876 GFP_ATOMIC)) 1877 goto nomem; 1878 1879 if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC)) 1880 goto nomem; 1881 1882 if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) 1883 return SCTP_DISPOSITION_DISCARD; 1884 1885 /* Make sure no new addresses are being added during the 1886 * restart. Though this is a pretty complicated attack 1887 * since you'd have to get inside the cookie. 1888 */ 1889 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) 1890 return SCTP_DISPOSITION_CONSUME; 1891 1892 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes 1893 * the peer has restarted (Action A), it MUST NOT setup a new 1894 * association but instead resend the SHUTDOWN ACK and send an ERROR 1895 * chunk with a "Cookie Received while Shutting Down" error cause to 1896 * its peer. 1897 */ 1898 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { 1899 disposition = __sctp_sf_do_9_2_reshutack(net, ep, asoc, 1900 SCTP_ST_CHUNK(chunk->chunk_hdr->type), 1901 chunk, commands); 1902 if (SCTP_DISPOSITION_NOMEM == disposition) 1903 goto nomem; 1904 1905 err = sctp_make_op_error(asoc, chunk, 1906 SCTP_ERROR_COOKIE_IN_SHUTDOWN, 1907 NULL, 0, 0); 1908 if (err) 1909 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1910 SCTP_CHUNK(err)); 1911 1912 return SCTP_DISPOSITION_CONSUME; 1913 } 1914 1915 /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked 1916 * data. Consider the optional choice of resending of this data. 1917 */ 1918 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 1919 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1920 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); 1921 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 1922 1923 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue 1924 * and ASCONF-ACK cache. 1925 */ 1926 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1927 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 1928 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL()); 1929 1930 /* Update the content of current association. */ 1931 if (sctp_sf_do_assoc_update((struct sctp_association *)asoc, new_asoc, commands)) 1932 goto nomem; 1933 1934 repl = sctp_make_cookie_ack(asoc, chunk); 1935 if (!repl) 1936 goto nomem; 1937 1938 /* Report association restart to upper layer. */ 1939 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, 1940 asoc->c.sinit_num_ostreams, 1941 asoc->c.sinit_max_instreams, 1942 NULL, GFP_ATOMIC); 1943 if (!ev) 1944 goto nomem_ev; 1945 1946 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1947 if ((sctp_state(asoc, SHUTDOWN_PENDING) || 1948 sctp_state(asoc, SHUTDOWN_SENT)) && 1949 (sctp_sstate(asoc->base.sk, CLOSING) || 1950 sock_flag(asoc->base.sk, SOCK_DEAD))) { 1951 /* If the socket has been closed by user, don't 1952 * transition to ESTABLISHED. Instead trigger SHUTDOWN 1953 * bundled with COOKIE_ACK. 1954 */ 1955 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1956 return sctp_sf_do_9_2_start_shutdown(net, ep, asoc, 1957 SCTP_ST_CHUNK(0), repl, 1958 commands); 1959 } else { 1960 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1961 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1962 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1963 } 1964 return SCTP_DISPOSITION_CONSUME; 1965 1966nomem_ev: 1967 sctp_chunk_free(repl); 1968nomem: 1969 return SCTP_DISPOSITION_NOMEM; 1970} 1971 1972/* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') 1973 * 1974 * Section 5.2.4 1975 * B) In this case, both sides may be attempting to start an association 1976 * at about the same time but the peer endpoint started its INIT 1977 * after responding to the local endpoint's INIT 1978 */ 1979/* This case represents an initialization collision. */ 1980static enum sctp_disposition sctp_sf_do_dupcook_b( 1981 struct net *net, 1982 const struct sctp_endpoint *ep, 1983 const struct sctp_association *asoc, 1984 struct sctp_chunk *chunk, 1985 struct sctp_cmd_seq *commands, 1986 struct sctp_association *new_asoc) 1987{ 1988 struct sctp_init_chunk *peer_init; 1989 struct sctp_chunk *repl; 1990 1991 /* new_asoc is a brand-new association, so these are not yet 1992 * side effects--it is safe to run them here. 1993 */ 1994 peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1); 1995 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1996 GFP_ATOMIC)) 1997 goto nomem; 1998 1999 if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC)) 2000 goto nomem; 2001 2002 if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) 2003 return SCTP_DISPOSITION_DISCARD; 2004 2005 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2006 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 2007 if (asoc->state < SCTP_STATE_ESTABLISHED) 2008 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 2009 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 2010 2011 /* Update the content of current association. */ 2012 if (sctp_sf_do_assoc_update((struct sctp_association *)asoc, new_asoc, commands)) 2013 goto nomem; 2014 2015 repl = sctp_make_cookie_ack(asoc, chunk); 2016 if (!repl) 2017 goto nomem; 2018 2019 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 2020 2021 /* RFC 2960 5.1 Normal Establishment of an Association 2022 * 2023 * D) IMPLEMENTATION NOTE: An implementation may choose to 2024 * send the Communication Up notification to the SCTP user 2025 * upon reception of a valid COOKIE ECHO chunk. 2026 * 2027 * Sadly, this needs to be implemented as a side-effect, because 2028 * we are not guaranteed to have set the association id of the real 2029 * association and so these notifications need to be delayed until 2030 * the association id is allocated. 2031 */ 2032 2033 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP)); 2034 2035 /* Sockets API Draft Section 5.3.1.6 2036 * When a peer sends a Adaptation Layer Indication parameter , SCTP 2037 * delivers this notification to inform the application that of the 2038 * peers requested adaptation layer. 2039 * 2040 * This also needs to be done as a side effect for the same reason as 2041 * above. 2042 */ 2043 if (asoc->peer.adaptation_ind) 2044 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL()); 2045 2046 if (!asoc->peer.auth_capable) 2047 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_NO_AUTH, SCTP_NULL()); 2048 2049 return SCTP_DISPOSITION_CONSUME; 2050 2051nomem: 2052 return SCTP_DISPOSITION_NOMEM; 2053} 2054 2055/* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') 2056 * 2057 * Section 5.2.4 2058 * C) In this case, the local endpoint's cookie has arrived late. 2059 * Before it arrived, the local endpoint sent an INIT and received an 2060 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag 2061 * but a new tag of its own. 2062 */ 2063/* This case represents an initialization collision. */ 2064static enum sctp_disposition sctp_sf_do_dupcook_c( 2065 struct net *net, 2066 const struct sctp_endpoint *ep, 2067 const struct sctp_association *asoc, 2068 struct sctp_chunk *chunk, 2069 struct sctp_cmd_seq *commands, 2070 struct sctp_association *new_asoc) 2071{ 2072 /* The cookie should be silently discarded. 2073 * The endpoint SHOULD NOT change states and should leave 2074 * any timers running. 2075 */ 2076 return SCTP_DISPOSITION_DISCARD; 2077} 2078 2079/* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') 2080 * 2081 * Section 5.2.4 2082 * 2083 * D) When both local and remote tags match the endpoint should always 2084 * enter the ESTABLISHED state, if it has not already done so. 2085 */ 2086/* This case represents an initialization collision. */ 2087static enum sctp_disposition sctp_sf_do_dupcook_d( 2088 struct net *net, 2089 const struct sctp_endpoint *ep, 2090 const struct sctp_association *asoc, 2091 struct sctp_chunk *chunk, 2092 struct sctp_cmd_seq *commands, 2093 struct sctp_association *new_asoc) 2094{ 2095 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL, *auth_ev = NULL; 2096 struct sctp_chunk *repl; 2097 2098 /* Clarification from Implementor's Guide: 2099 * D) When both local and remote tags match the endpoint should 2100 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. 2101 * It should stop any cookie timer that may be running and send 2102 * a COOKIE ACK. 2103 */ 2104 2105 if (!sctp_auth_chunk_verify(net, chunk, asoc)) 2106 return SCTP_DISPOSITION_DISCARD; 2107 2108 /* Don't accidentally move back into established state. */ 2109 if (asoc->state < SCTP_STATE_ESTABLISHED) { 2110 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2111 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2112 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2113 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 2114 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 2115 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, 2116 SCTP_NULL()); 2117 2118 /* RFC 2960 5.1 Normal Establishment of an Association 2119 * 2120 * D) IMPLEMENTATION NOTE: An implementation may choose 2121 * to send the Communication Up notification to the 2122 * SCTP user upon reception of a valid COOKIE 2123 * ECHO chunk. 2124 */ 2125 ev = sctp_ulpevent_make_assoc_change(asoc, 0, 2126 SCTP_COMM_UP, 0, 2127 asoc->c.sinit_num_ostreams, 2128 asoc->c.sinit_max_instreams, 2129 NULL, GFP_ATOMIC); 2130 if (!ev) 2131 goto nomem; 2132 2133 /* Sockets API Draft Section 5.3.1.6 2134 * When a peer sends a Adaptation Layer Indication parameter, 2135 * SCTP delivers this notification to inform the application 2136 * that of the peers requested adaptation layer. 2137 */ 2138 if (asoc->peer.adaptation_ind) { 2139 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc, 2140 GFP_ATOMIC); 2141 if (!ai_ev) 2142 goto nomem; 2143 2144 } 2145 2146 if (!asoc->peer.auth_capable) { 2147 auth_ev = sctp_ulpevent_make_authkey(asoc, 0, 2148 SCTP_AUTH_NO_AUTH, 2149 GFP_ATOMIC); 2150 if (!auth_ev) 2151 goto nomem; 2152 } 2153 } 2154 2155 repl = sctp_make_cookie_ack(asoc, chunk); 2156 if (!repl) 2157 goto nomem; 2158 2159 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 2160 2161 if (ev) 2162 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2163 SCTP_ULPEVENT(ev)); 2164 if (ai_ev) 2165 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2166 SCTP_ULPEVENT(ai_ev)); 2167 if (auth_ev) 2168 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2169 SCTP_ULPEVENT(auth_ev)); 2170 2171 return SCTP_DISPOSITION_CONSUME; 2172 2173nomem: 2174 if (auth_ev) 2175 sctp_ulpevent_free(auth_ev); 2176 if (ai_ev) 2177 sctp_ulpevent_free(ai_ev); 2178 if (ev) 2179 sctp_ulpevent_free(ev); 2180 return SCTP_DISPOSITION_NOMEM; 2181} 2182 2183/* 2184 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying 2185 * chunk was retransmitted and then delayed in the network. 2186 * 2187 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists 2188 * 2189 * Verification Tag: None. Do cookie validation. 2190 * 2191 * Inputs 2192 * (endpoint, asoc, chunk) 2193 * 2194 * Outputs 2195 * (asoc, reply_msg, msg_up, timers, counters) 2196 * 2197 * The return value is the disposition of the chunk. 2198 */ 2199enum sctp_disposition sctp_sf_do_5_2_4_dupcook( 2200 struct net *net, 2201 const struct sctp_endpoint *ep, 2202 const struct sctp_association *asoc, 2203 const union sctp_subtype type, 2204 void *arg, 2205 struct sctp_cmd_seq *commands) 2206{ 2207 struct sctp_association *new_asoc; 2208 struct sctp_chunk *chunk = arg; 2209 enum sctp_disposition retval; 2210 struct sctp_chunk *err_chk_p; 2211 int error = 0; 2212 char action; 2213 2214 /* Make sure that the chunk has a valid length from the protocol 2215 * perspective. In this case check to make sure we have at least 2216 * enough for the chunk header. Cookie length verification is 2217 * done later. 2218 */ 2219 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) { 2220 if (!sctp_vtag_verify(chunk, asoc)) 2221 asoc = NULL; 2222 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, commands); 2223 } 2224 2225 /* "Decode" the chunk. We have no optional parameters so we 2226 * are in good shape. 2227 */ 2228 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; 2229 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 2230 sizeof(struct sctp_chunkhdr))) 2231 goto nomem; 2232 2233 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie 2234 * of a duplicate COOKIE ECHO match the Verification Tags of the 2235 * current association, consider the State Cookie valid even if 2236 * the lifespan is exceeded. 2237 */ 2238 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 2239 &err_chk_p); 2240 2241 /* FIXME: 2242 * If the re-build failed, what is the proper error path 2243 * from here? 2244 * 2245 * [We should abort the association. --piggy] 2246 */ 2247 if (!new_asoc) { 2248 /* FIXME: Several errors are possible. A bad cookie should 2249 * be silently discarded, but think about logging it too. 2250 */ 2251 switch (error) { 2252 case -SCTP_IERROR_NOMEM: 2253 goto nomem; 2254 2255 case -SCTP_IERROR_STALE_COOKIE: 2256 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 2257 err_chk_p); 2258 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2259 case -SCTP_IERROR_BAD_SIG: 2260 default: 2261 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2262 } 2263 } 2264 2265 /* Set temp so that it won't be added into hashtable */ 2266 new_asoc->temp = 1; 2267 2268 /* Compare the tie_tag in cookie with the verification tag of 2269 * current association. 2270 */ 2271 action = sctp_tietags_compare(new_asoc, asoc); 2272 2273 /* In cases C and E the association doesn't enter the ESTABLISHED 2274 * state, so there is no need to call security_sctp_assoc_request(). 2275 */ 2276 switch (action) { 2277 case 'A': /* Association restart. */ 2278 case 'B': /* Collision case B. */ 2279 case 'D': /* Collision case D. */ 2280 /* Update socket peer label if first association. */ 2281 if (security_sctp_assoc_request((struct sctp_association *)asoc, 2282 chunk->head_skb ?: chunk->skb)) { 2283 sctp_association_free(new_asoc); 2284 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2285 } 2286 break; 2287 } 2288 2289 switch (action) { 2290 case 'A': /* Association restart. */ 2291 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands, 2292 new_asoc); 2293 break; 2294 2295 case 'B': /* Collision case B. */ 2296 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands, 2297 new_asoc); 2298 break; 2299 2300 case 'C': /* Collision case C. */ 2301 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands, 2302 new_asoc); 2303 break; 2304 2305 case 'D': /* Collision case D. */ 2306 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands, 2307 new_asoc); 2308 break; 2309 2310 default: /* Discard packet for all others. */ 2311 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2312 break; 2313 } 2314 2315 /* Delete the temporary new association. */ 2316 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc)); 2317 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 2318 2319 /* Restore association pointer to provide SCTP command interpreter 2320 * with a valid context in case it needs to manipulate 2321 * the queues */ 2322 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, 2323 SCTP_ASOC((struct sctp_association *)asoc)); 2324 2325 return retval; 2326 2327nomem: 2328 return SCTP_DISPOSITION_NOMEM; 2329} 2330 2331/* 2332 * Process an ABORT. (SHUTDOWN-PENDING state) 2333 * 2334 * See sctp_sf_do_9_1_abort(). 2335 */ 2336enum sctp_disposition sctp_sf_shutdown_pending_abort( 2337 struct net *net, 2338 const struct sctp_endpoint *ep, 2339 const struct sctp_association *asoc, 2340 const union sctp_subtype type, 2341 void *arg, 2342 struct sctp_cmd_seq *commands) 2343{ 2344 struct sctp_chunk *chunk = arg; 2345 2346 if (!sctp_vtag_verify_either(chunk, asoc)) 2347 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2348 2349 /* Make sure that the ABORT chunk has a valid length. 2350 * Since this is an ABORT chunk, we have to discard it 2351 * because of the following text: 2352 * RFC 2960, Section 3.3.7 2353 * If an endpoint receives an ABORT with a format error or for an 2354 * association that doesn't exist, it MUST silently discard it. 2355 * Because the length is "invalid", we can't really discard just 2356 * as we do not know its true length. So, to be safe, discard the 2357 * packet. 2358 */ 2359 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2360 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2361 2362 /* ADD-IP: Special case for ABORT chunks 2363 * F4) One special consideration is that ABORT Chunks arriving 2364 * destined to the IP address being deleted MUST be 2365 * ignored (see Section 5.3.1 for further details). 2366 */ 2367 if (SCTP_ADDR_DEL == 2368 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2369 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2370 2371 if (!sctp_err_chunk_valid(chunk)) 2372 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2373 2374 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2375} 2376 2377/* 2378 * Process an ABORT. (SHUTDOWN-SENT state) 2379 * 2380 * See sctp_sf_do_9_1_abort(). 2381 */ 2382enum sctp_disposition sctp_sf_shutdown_sent_abort( 2383 struct net *net, 2384 const struct sctp_endpoint *ep, 2385 const struct sctp_association *asoc, 2386 const union sctp_subtype type, 2387 void *arg, 2388 struct sctp_cmd_seq *commands) 2389{ 2390 struct sctp_chunk *chunk = arg; 2391 2392 if (!sctp_vtag_verify_either(chunk, asoc)) 2393 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2394 2395 /* Make sure that the ABORT chunk has a valid length. 2396 * Since this is an ABORT chunk, we have to discard it 2397 * because of the following text: 2398 * RFC 2960, Section 3.3.7 2399 * If an endpoint receives an ABORT with a format error or for an 2400 * association that doesn't exist, it MUST silently discard it. 2401 * Because the length is "invalid", we can't really discard just 2402 * as we do not know its true length. So, to be safe, discard the 2403 * packet. 2404 */ 2405 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2406 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2407 2408 /* ADD-IP: Special case for ABORT chunks 2409 * F4) One special consideration is that ABORT Chunks arriving 2410 * destined to the IP address being deleted MUST be 2411 * ignored (see Section 5.3.1 for further details). 2412 */ 2413 if (SCTP_ADDR_DEL == 2414 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2415 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2416 2417 if (!sctp_err_chunk_valid(chunk)) 2418 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2419 2420 /* Stop the T2-shutdown timer. */ 2421 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2422 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2423 2424 /* Stop the T5-shutdown guard timer. */ 2425 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2426 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2427 2428 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2429} 2430 2431/* 2432 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2433 * 2434 * See sctp_sf_do_9_1_abort(). 2435 */ 2436enum sctp_disposition sctp_sf_shutdown_ack_sent_abort( 2437 struct net *net, 2438 const struct sctp_endpoint *ep, 2439 const struct sctp_association *asoc, 2440 const union sctp_subtype type, 2441 void *arg, 2442 struct sctp_cmd_seq *commands) 2443{ 2444 /* The same T2 timer, so we should be able to use 2445 * common function with the SHUTDOWN-SENT state. 2446 */ 2447 return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands); 2448} 2449 2450/* 2451 * Handle an Error received in COOKIE_ECHOED state. 2452 * 2453 * Only handle the error type of stale COOKIE Error, the other errors will 2454 * be ignored. 2455 * 2456 * Inputs 2457 * (endpoint, asoc, chunk) 2458 * 2459 * Outputs 2460 * (asoc, reply_msg, msg_up, timers, counters) 2461 * 2462 * The return value is the disposition of the chunk. 2463 */ 2464enum sctp_disposition sctp_sf_cookie_echoed_err( 2465 struct net *net, 2466 const struct sctp_endpoint *ep, 2467 const struct sctp_association *asoc, 2468 const union sctp_subtype type, 2469 void *arg, 2470 struct sctp_cmd_seq *commands) 2471{ 2472 struct sctp_chunk *chunk = arg; 2473 struct sctp_errhdr *err; 2474 2475 if (!sctp_vtag_verify(chunk, asoc)) 2476 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2477 2478 /* Make sure that the ERROR chunk has a valid length. 2479 * The parameter walking depends on this as well. 2480 */ 2481 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk))) 2482 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2483 commands); 2484 2485 /* Process the error here */ 2486 /* FUTURE FIXME: When PR-SCTP related and other optional 2487 * parms are emitted, this will have to change to handle multiple 2488 * errors. 2489 */ 2490 sctp_walk_errors(err, chunk->chunk_hdr) { 2491 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2492 return sctp_sf_do_5_2_6_stale(net, ep, asoc, type, 2493 arg, commands); 2494 } 2495 2496 /* It is possible to have malformed error causes, and that 2497 * will cause us to end the walk early. However, since 2498 * we are discarding the packet, there should be no adverse 2499 * affects. 2500 */ 2501 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2502} 2503 2504/* 2505 * Handle a Stale COOKIE Error 2506 * 2507 * Section: 5.2.6 Handle Stale COOKIE Error 2508 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2509 * one of the following three alternatives. 2510 * ... 2511 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2512 * Preservative parameter requesting an extension to the lifetime of 2513 * the State Cookie. When calculating the time extension, an 2514 * implementation SHOULD use the RTT information measured based on the 2515 * previous COOKIE ECHO / ERROR exchange, and should add no more 2516 * than 1 second beyond the measured RTT, due to long State Cookie 2517 * lifetimes making the endpoint more subject to a replay attack. 2518 * 2519 * Verification Tag: Not explicit, but safe to ignore. 2520 * 2521 * Inputs 2522 * (endpoint, asoc, chunk) 2523 * 2524 * Outputs 2525 * (asoc, reply_msg, msg_up, timers, counters) 2526 * 2527 * The return value is the disposition of the chunk. 2528 */ 2529static enum sctp_disposition sctp_sf_do_5_2_6_stale( 2530 struct net *net, 2531 const struct sctp_endpoint *ep, 2532 const struct sctp_association *asoc, 2533 const union sctp_subtype type, 2534 void *arg, 2535 struct sctp_cmd_seq *commands) 2536{ 2537 int attempts = asoc->init_err_counter + 1; 2538 struct sctp_chunk *chunk = arg, *reply; 2539 struct sctp_cookie_preserve_param bht; 2540 struct sctp_bind_addr *bp; 2541 struct sctp_errhdr *err; 2542 u32 stale; 2543 2544 if (attempts > asoc->max_init_attempts) { 2545 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 2546 SCTP_ERROR(ETIMEDOUT)); 2547 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2548 SCTP_PERR(SCTP_ERROR_STALE_COOKIE)); 2549 return SCTP_DISPOSITION_DELETE_TCB; 2550 } 2551 2552 err = (struct sctp_errhdr *)(chunk->skb->data); 2553 2554 /* When calculating the time extension, an implementation 2555 * SHOULD use the RTT information measured based on the 2556 * previous COOKIE ECHO / ERROR exchange, and should add no 2557 * more than 1 second beyond the measured RTT, due to long 2558 * State Cookie lifetimes making the endpoint more subject to 2559 * a replay attack. 2560 * Measure of Staleness's unit is usec. (1/1000000 sec) 2561 * Suggested Cookie Life-span Increment's unit is msec. 2562 * (1/1000 sec) 2563 * In general, if you use the suggested cookie life, the value 2564 * found in the field of measure of staleness should be doubled 2565 * to give ample time to retransmit the new cookie and thus 2566 * yield a higher probability of success on the reattempt. 2567 */ 2568 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err))); 2569 stale = (stale * 2) / 1000; 2570 2571 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2572 bht.param_hdr.length = htons(sizeof(bht)); 2573 bht.lifespan_increment = htonl(stale); 2574 2575 /* Build that new INIT chunk. */ 2576 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2577 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2578 if (!reply) 2579 goto nomem; 2580 2581 sctp_addto_chunk(reply, sizeof(bht), &bht); 2582 2583 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2584 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2585 2586 /* Stop pending T3-rtx and heartbeat timers */ 2587 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2588 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2589 2590 /* Delete non-primary peer ip addresses since we are transitioning 2591 * back to the COOKIE-WAIT state 2592 */ 2593 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2594 2595 /* If we've sent any data bundled with COOKIE-ECHO we will need to 2596 * resend 2597 */ 2598 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN, 2599 SCTP_TRANSPORT(asoc->peer.primary_path)); 2600 2601 /* Cast away the const modifier, as we want to just 2602 * rerun it through as a sideffect. 2603 */ 2604 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2605 2606 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2607 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2608 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2609 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2610 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2611 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2612 2613 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2614 2615 return SCTP_DISPOSITION_CONSUME; 2616 2617nomem: 2618 return SCTP_DISPOSITION_NOMEM; 2619} 2620 2621/* 2622 * Process an ABORT. 2623 * 2624 * Section: 9.1 2625 * After checking the Verification Tag, the receiving endpoint shall 2626 * remove the association from its record, and shall report the 2627 * termination to its upper layer. 2628 * 2629 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2630 * B) Rules for packet carrying ABORT: 2631 * 2632 * - The endpoint shall always fill in the Verification Tag field of the 2633 * outbound packet with the destination endpoint's tag value if it 2634 * is known. 2635 * 2636 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2637 * MUST follow the procedure described in Section 8.4. 2638 * 2639 * - The receiver MUST accept the packet if the Verification Tag 2640 * matches either its own tag, OR the tag of its peer. Otherwise, the 2641 * receiver MUST silently discard the packet and take no further 2642 * action. 2643 * 2644 * Inputs 2645 * (endpoint, asoc, chunk) 2646 * 2647 * Outputs 2648 * (asoc, reply_msg, msg_up, timers, counters) 2649 * 2650 * The return value is the disposition of the chunk. 2651 */ 2652enum sctp_disposition sctp_sf_do_9_1_abort( 2653 struct net *net, 2654 const struct sctp_endpoint *ep, 2655 const struct sctp_association *asoc, 2656 const union sctp_subtype type, 2657 void *arg, 2658 struct sctp_cmd_seq *commands) 2659{ 2660 struct sctp_chunk *chunk = arg; 2661 2662 if (!sctp_vtag_verify_either(chunk, asoc)) 2663 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2664 2665 /* Make sure that the ABORT chunk has a valid length. 2666 * Since this is an ABORT chunk, we have to discard it 2667 * because of the following text: 2668 * RFC 2960, Section 3.3.7 2669 * If an endpoint receives an ABORT with a format error or for an 2670 * association that doesn't exist, it MUST silently discard it. 2671 * Because the length is "invalid", we can't really discard just 2672 * as we do not know its true length. So, to be safe, discard the 2673 * packet. 2674 */ 2675 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2676 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2677 2678 /* ADD-IP: Special case for ABORT chunks 2679 * F4) One special consideration is that ABORT Chunks arriving 2680 * destined to the IP address being deleted MUST be 2681 * ignored (see Section 5.3.1 for further details). 2682 */ 2683 if (SCTP_ADDR_DEL == 2684 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2685 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2686 2687 if (!sctp_err_chunk_valid(chunk)) 2688 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2689 2690 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2691} 2692 2693static enum sctp_disposition __sctp_sf_do_9_1_abort( 2694 struct net *net, 2695 const struct sctp_endpoint *ep, 2696 const struct sctp_association *asoc, 2697 const union sctp_subtype type, 2698 void *arg, 2699 struct sctp_cmd_seq *commands) 2700{ 2701 __be16 error = SCTP_ERROR_NO_ERROR; 2702 struct sctp_chunk *chunk = arg; 2703 unsigned int len; 2704 2705 /* See if we have an error cause code in the chunk. */ 2706 len = ntohs(chunk->chunk_hdr->length); 2707 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2708 error = ((struct sctp_errhdr *)chunk->skb->data)->cause; 2709 2710 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET)); 2711 /* ASSOC_FAILED will DELETE_TCB. */ 2712 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error)); 2713 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2714 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 2715 2716 return SCTP_DISPOSITION_ABORT; 2717} 2718 2719/* 2720 * Process an ABORT. (COOKIE-WAIT state) 2721 * 2722 * See sctp_sf_do_9_1_abort() above. 2723 */ 2724enum sctp_disposition sctp_sf_cookie_wait_abort( 2725 struct net *net, 2726 const struct sctp_endpoint *ep, 2727 const struct sctp_association *asoc, 2728 const union sctp_subtype type, 2729 void *arg, 2730 struct sctp_cmd_seq *commands) 2731{ 2732 __be16 error = SCTP_ERROR_NO_ERROR; 2733 struct sctp_chunk *chunk = arg; 2734 unsigned int len; 2735 2736 if (!sctp_vtag_verify_either(chunk, asoc)) 2737 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2738 2739 /* Make sure that the ABORT chunk has a valid length. 2740 * Since this is an ABORT chunk, we have to discard it 2741 * because of the following text: 2742 * RFC 2960, Section 3.3.7 2743 * If an endpoint receives an ABORT with a format error or for an 2744 * association that doesn't exist, it MUST silently discard it. 2745 * Because the length is "invalid", we can't really discard just 2746 * as we do not know its true length. So, to be safe, discard the 2747 * packet. 2748 */ 2749 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2750 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2751 2752 /* See if we have an error cause code in the chunk. */ 2753 len = ntohs(chunk->chunk_hdr->length); 2754 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2755 error = ((struct sctp_errhdr *)chunk->skb->data)->cause; 2756 2757 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc, 2758 chunk->transport); 2759} 2760 2761/* 2762 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2763 */ 2764enum sctp_disposition sctp_sf_cookie_wait_icmp_abort( 2765 struct net *net, 2766 const struct sctp_endpoint *ep, 2767 const struct sctp_association *asoc, 2768 const union sctp_subtype type, 2769 void *arg, 2770 struct sctp_cmd_seq *commands) 2771{ 2772 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR, 2773 ENOPROTOOPT, asoc, 2774 (struct sctp_transport *)arg); 2775} 2776 2777/* 2778 * Process an ABORT. (COOKIE-ECHOED state) 2779 */ 2780enum sctp_disposition sctp_sf_cookie_echoed_abort( 2781 struct net *net, 2782 const struct sctp_endpoint *ep, 2783 const struct sctp_association *asoc, 2784 const union sctp_subtype type, 2785 void *arg, 2786 struct sctp_cmd_seq *commands) 2787{ 2788 /* There is a single T1 timer, so we should be able to use 2789 * common function with the COOKIE-WAIT state. 2790 */ 2791 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands); 2792} 2793 2794/* 2795 * Stop T1 timer and abort association with "INIT failed". 2796 * 2797 * This is common code called by several sctp_sf_*_abort() functions above. 2798 */ 2799static enum sctp_disposition sctp_stop_t1_and_abort( 2800 struct net *net, 2801 struct sctp_cmd_seq *commands, 2802 __be16 error, int sk_err, 2803 const struct sctp_association *asoc, 2804 struct sctp_transport *transport) 2805{ 2806 pr_debug("%s: ABORT received (INIT)\n", __func__); 2807 2808 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2809 SCTP_STATE(SCTP_STATE_CLOSED)); 2810 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2811 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2812 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2813 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err)); 2814 /* CMD_INIT_FAILED will DELETE_TCB. */ 2815 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2816 SCTP_PERR(error)); 2817 2818 return SCTP_DISPOSITION_ABORT; 2819} 2820 2821/* 2822 * sctp_sf_do_9_2_shut 2823 * 2824 * Section: 9.2 2825 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2826 * - enter the SHUTDOWN-RECEIVED state, 2827 * 2828 * - stop accepting new data from its SCTP user 2829 * 2830 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2831 * that all its outstanding DATA chunks have been received by the 2832 * SHUTDOWN sender. 2833 * 2834 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2835 * send a SHUTDOWN in response to a ULP request. And should discard 2836 * subsequent SHUTDOWN chunks. 2837 * 2838 * If there are still outstanding DATA chunks left, the SHUTDOWN 2839 * receiver shall continue to follow normal data transmission 2840 * procedures defined in Section 6 until all outstanding DATA chunks 2841 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2842 * new data from its SCTP user. 2843 * 2844 * Verification Tag: 8.5 Verification Tag [Normal verification] 2845 * 2846 * Inputs 2847 * (endpoint, asoc, chunk) 2848 * 2849 * Outputs 2850 * (asoc, reply_msg, msg_up, timers, counters) 2851 * 2852 * The return value is the disposition of the chunk. 2853 */ 2854enum sctp_disposition sctp_sf_do_9_2_shutdown( 2855 struct net *net, 2856 const struct sctp_endpoint *ep, 2857 const struct sctp_association *asoc, 2858 const union sctp_subtype type, 2859 void *arg, 2860 struct sctp_cmd_seq *commands) 2861{ 2862 enum sctp_disposition disposition; 2863 struct sctp_chunk *chunk = arg; 2864 struct sctp_shutdownhdr *sdh; 2865 struct sctp_ulpevent *ev; 2866 __u32 ctsn; 2867 2868 if (!sctp_vtag_verify(chunk, asoc)) 2869 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2870 2871 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2872 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk))) 2873 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2874 commands); 2875 2876 /* Convert the elaborate header. */ 2877 sdh = (struct sctp_shutdownhdr *)chunk->skb->data; 2878 skb_pull(chunk->skb, sizeof(*sdh)); 2879 chunk->subh.shutdown_hdr = sdh; 2880 ctsn = ntohl(sdh->cum_tsn_ack); 2881 2882 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2883 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2884 asoc->ctsn_ack_point); 2885 2886 return SCTP_DISPOSITION_DISCARD; 2887 } 2888 2889 /* If Cumulative TSN Ack beyond the max tsn currently 2890 * send, terminating the association and respond to the 2891 * sender with an ABORT. 2892 */ 2893 if (!TSN_lt(ctsn, asoc->next_tsn)) 2894 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2895 2896 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2897 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2898 * inform the application that it should cease sending data. 2899 */ 2900 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2901 if (!ev) { 2902 disposition = SCTP_DISPOSITION_NOMEM; 2903 goto out; 2904 } 2905 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2906 2907 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2908 * - enter the SHUTDOWN-RECEIVED state, 2909 * - stop accepting new data from its SCTP user 2910 * 2911 * [This is implicit in the new state.] 2912 */ 2913 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2914 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2915 disposition = SCTP_DISPOSITION_CONSUME; 2916 2917 if (sctp_outq_is_empty(&asoc->outqueue)) { 2918 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type, 2919 arg, commands); 2920 } 2921 2922 if (SCTP_DISPOSITION_NOMEM == disposition) 2923 goto out; 2924 2925 /* - verify, by checking the Cumulative TSN Ack field of the 2926 * chunk, that all its outstanding DATA chunks have been 2927 * received by the SHUTDOWN sender. 2928 */ 2929 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2930 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2931 2932out: 2933 return disposition; 2934} 2935 2936/* 2937 * sctp_sf_do_9_2_shut_ctsn 2938 * 2939 * Once an endpoint has reached the SHUTDOWN-RECEIVED state, 2940 * it MUST NOT send a SHUTDOWN in response to a ULP request. 2941 * The Cumulative TSN Ack of the received SHUTDOWN chunk 2942 * MUST be processed. 2943 */ 2944enum sctp_disposition sctp_sf_do_9_2_shut_ctsn( 2945 struct net *net, 2946 const struct sctp_endpoint *ep, 2947 const struct sctp_association *asoc, 2948 const union sctp_subtype type, 2949 void *arg, 2950 struct sctp_cmd_seq *commands) 2951{ 2952 struct sctp_chunk *chunk = arg; 2953 struct sctp_shutdownhdr *sdh; 2954 __u32 ctsn; 2955 2956 if (!sctp_vtag_verify(chunk, asoc)) 2957 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2958 2959 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2960 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk))) 2961 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2962 commands); 2963 2964 sdh = (struct sctp_shutdownhdr *)chunk->skb->data; 2965 ctsn = ntohl(sdh->cum_tsn_ack); 2966 2967 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2968 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2969 asoc->ctsn_ack_point); 2970 2971 return SCTP_DISPOSITION_DISCARD; 2972 } 2973 2974 /* If Cumulative TSN Ack beyond the max tsn currently 2975 * send, terminating the association and respond to the 2976 * sender with an ABORT. 2977 */ 2978 if (!TSN_lt(ctsn, asoc->next_tsn)) 2979 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2980 2981 /* verify, by checking the Cumulative TSN Ack field of the 2982 * chunk, that all its outstanding DATA chunks have been 2983 * received by the SHUTDOWN sender. 2984 */ 2985 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2986 SCTP_BE32(sdh->cum_tsn_ack)); 2987 2988 return SCTP_DISPOSITION_CONSUME; 2989} 2990 2991/* RFC 2960 9.2 2992 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2993 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 2994 * transport addresses (either in the IP addresses or in the INIT chunk) 2995 * that belong to this association, it should discard the INIT chunk and 2996 * retransmit the SHUTDOWN ACK chunk. 2997 */ 2998static enum sctp_disposition 2999__sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep, 3000 const struct sctp_association *asoc, 3001 const union sctp_subtype type, void *arg, 3002 struct sctp_cmd_seq *commands) 3003{ 3004 struct sctp_chunk *chunk = arg; 3005 struct sctp_chunk *reply; 3006 3007 /* Make sure that the chunk has a valid length */ 3008 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3009 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3010 commands); 3011 3012 /* Since we are not going to really process this INIT, there 3013 * is no point in verifying chunk boundaries. Just generate 3014 * the SHUTDOWN ACK. 3015 */ 3016 reply = sctp_make_shutdown_ack(asoc, chunk); 3017 if (NULL == reply) 3018 goto nomem; 3019 3020 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 3021 * the T2-SHUTDOWN timer. 3022 */ 3023 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 3024 3025 /* and restart the T2-shutdown timer. */ 3026 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3027 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3028 3029 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3030 3031 return SCTP_DISPOSITION_CONSUME; 3032nomem: 3033 return SCTP_DISPOSITION_NOMEM; 3034} 3035 3036enum sctp_disposition 3037sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep, 3038 const struct sctp_association *asoc, 3039 const union sctp_subtype type, void *arg, 3040 struct sctp_cmd_seq *commands) 3041{ 3042 struct sctp_chunk *chunk = arg; 3043 3044 if (!chunk->singleton) 3045 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3046 3047 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk))) 3048 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3049 3050 if (chunk->sctp_hdr->vtag != 0) 3051 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 3052 3053 return __sctp_sf_do_9_2_reshutack(net, ep, asoc, type, arg, commands); 3054} 3055 3056/* 3057 * sctp_sf_do_ecn_cwr 3058 * 3059 * Section: Appendix A: Explicit Congestion Notification 3060 * 3061 * CWR: 3062 * 3063 * RFC 2481 details a specific bit for a sender to send in the header of 3064 * its next outbound TCP segment to indicate to its peer that it has 3065 * reduced its congestion window. This is termed the CWR bit. For 3066 * SCTP the same indication is made by including the CWR chunk. 3067 * This chunk contains one data element, i.e. the TSN number that 3068 * was sent in the ECNE chunk. This element represents the lowest 3069 * TSN number in the datagram that was originally marked with the 3070 * CE bit. 3071 * 3072 * Verification Tag: 8.5 Verification Tag [Normal verification] 3073 * Inputs 3074 * (endpoint, asoc, chunk) 3075 * 3076 * Outputs 3077 * (asoc, reply_msg, msg_up, timers, counters) 3078 * 3079 * The return value is the disposition of the chunk. 3080 */ 3081enum sctp_disposition sctp_sf_do_ecn_cwr(struct net *net, 3082 const struct sctp_endpoint *ep, 3083 const struct sctp_association *asoc, 3084 const union sctp_subtype type, 3085 void *arg, 3086 struct sctp_cmd_seq *commands) 3087{ 3088 struct sctp_chunk *chunk = arg; 3089 struct sctp_cwrhdr *cwr; 3090 u32 lowest_tsn; 3091 3092 if (!sctp_vtag_verify(chunk, asoc)) 3093 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3094 3095 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk))) 3096 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3097 commands); 3098 3099 cwr = (struct sctp_cwrhdr *)chunk->skb->data; 3100 skb_pull(chunk->skb, sizeof(*cwr)); 3101 3102 lowest_tsn = ntohl(cwr->lowest_tsn); 3103 3104 /* Does this CWR ack the last sent congestion notification? */ 3105 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) { 3106 /* Stop sending ECNE. */ 3107 sctp_add_cmd_sf(commands, 3108 SCTP_CMD_ECN_CWR, 3109 SCTP_U32(lowest_tsn)); 3110 } 3111 return SCTP_DISPOSITION_CONSUME; 3112} 3113 3114/* 3115 * sctp_sf_do_ecne 3116 * 3117 * Section: Appendix A: Explicit Congestion Notification 3118 * 3119 * ECN-Echo 3120 * 3121 * RFC 2481 details a specific bit for a receiver to send back in its 3122 * TCP acknowledgements to notify the sender of the Congestion 3123 * Experienced (CE) bit having arrived from the network. For SCTP this 3124 * same indication is made by including the ECNE chunk. This chunk 3125 * contains one data element, i.e. the lowest TSN associated with the IP 3126 * datagram marked with the CE bit..... 3127 * 3128 * Verification Tag: 8.5 Verification Tag [Normal verification] 3129 * Inputs 3130 * (endpoint, asoc, chunk) 3131 * 3132 * Outputs 3133 * (asoc, reply_msg, msg_up, timers, counters) 3134 * 3135 * The return value is the disposition of the chunk. 3136 */ 3137enum sctp_disposition sctp_sf_do_ecne(struct net *net, 3138 const struct sctp_endpoint *ep, 3139 const struct sctp_association *asoc, 3140 const union sctp_subtype type, 3141 void *arg, struct sctp_cmd_seq *commands) 3142{ 3143 struct sctp_chunk *chunk = arg; 3144 struct sctp_ecnehdr *ecne; 3145 3146 if (!sctp_vtag_verify(chunk, asoc)) 3147 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3148 3149 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk))) 3150 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3151 commands); 3152 3153 ecne = (struct sctp_ecnehdr *)chunk->skb->data; 3154 skb_pull(chunk->skb, sizeof(*ecne)); 3155 3156 /* If this is a newer ECNE than the last CWR packet we sent out */ 3157 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 3158 SCTP_U32(ntohl(ecne->lowest_tsn))); 3159 3160 return SCTP_DISPOSITION_CONSUME; 3161} 3162 3163/* 3164 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 3165 * 3166 * The SCTP endpoint MUST always acknowledge the reception of each valid 3167 * DATA chunk. 3168 * 3169 * The guidelines on delayed acknowledgement algorithm specified in 3170 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 3171 * acknowledgement SHOULD be generated for at least every second packet 3172 * (not every second DATA chunk) received, and SHOULD be generated within 3173 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 3174 * situations it may be beneficial for an SCTP transmitter to be more 3175 * conservative than the algorithms detailed in this document allow. 3176 * However, an SCTP transmitter MUST NOT be more aggressive than the 3177 * following algorithms allow. 3178 * 3179 * A SCTP receiver MUST NOT generate more than one SACK for every 3180 * incoming packet, other than to update the offered window as the 3181 * receiving application consumes new data. 3182 * 3183 * Verification Tag: 8.5 Verification Tag [Normal verification] 3184 * 3185 * Inputs 3186 * (endpoint, asoc, chunk) 3187 * 3188 * Outputs 3189 * (asoc, reply_msg, msg_up, timers, counters) 3190 * 3191 * The return value is the disposition of the chunk. 3192 */ 3193enum sctp_disposition sctp_sf_eat_data_6_2(struct net *net, 3194 const struct sctp_endpoint *ep, 3195 const struct sctp_association *asoc, 3196 const union sctp_subtype type, 3197 void *arg, 3198 struct sctp_cmd_seq *commands) 3199{ 3200 union sctp_arg force = SCTP_NOFORCE(); 3201 struct sctp_chunk *chunk = arg; 3202 int error; 3203 3204 if (!sctp_vtag_verify(chunk, asoc)) { 3205 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3206 SCTP_NULL()); 3207 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3208 } 3209 3210 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream))) 3211 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3212 commands); 3213 3214 error = sctp_eat_data(asoc, chunk, commands); 3215 switch (error) { 3216 case SCTP_IERROR_NO_ERROR: 3217 break; 3218 case SCTP_IERROR_HIGH_TSN: 3219 case SCTP_IERROR_BAD_STREAM: 3220 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3221 goto discard_noforce; 3222 case SCTP_IERROR_DUP_TSN: 3223 case SCTP_IERROR_IGNORE_TSN: 3224 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3225 goto discard_force; 3226 case SCTP_IERROR_NO_DATA: 3227 return SCTP_DISPOSITION_ABORT; 3228 case SCTP_IERROR_PROTO_VIOLATION: 3229 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3230 (u8 *)chunk->subh.data_hdr, 3231 sctp_datahdr_len(&asoc->stream)); 3232 default: 3233 BUG(); 3234 } 3235 3236 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM) 3237 force = SCTP_FORCE(); 3238 3239 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 3240 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3241 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3242 } 3243 3244 /* If this is the last chunk in a packet, we need to count it 3245 * toward sack generation. Note that we need to SACK every 3246 * OTHER packet containing data chunks, EVEN IF WE DISCARD 3247 * THEM. We elect to NOT generate SACK's if the chunk fails 3248 * the verification tag test. 3249 * 3250 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3251 * 3252 * The SCTP endpoint MUST always acknowledge the reception of 3253 * each valid DATA chunk. 3254 * 3255 * The guidelines on delayed acknowledgement algorithm 3256 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 3257 * Specifically, an acknowledgement SHOULD be generated for at 3258 * least every second packet (not every second DATA chunk) 3259 * received, and SHOULD be generated within 200 ms of the 3260 * arrival of any unacknowledged DATA chunk. In some 3261 * situations it may be beneficial for an SCTP transmitter to 3262 * be more conservative than the algorithms detailed in this 3263 * document allow. However, an SCTP transmitter MUST NOT be 3264 * more aggressive than the following algorithms allow. 3265 */ 3266 if (chunk->end_of_packet) 3267 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3268 3269 return SCTP_DISPOSITION_CONSUME; 3270 3271discard_force: 3272 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3273 * 3274 * When a packet arrives with duplicate DATA chunk(s) and with 3275 * no new DATA chunk(s), the endpoint MUST immediately send a 3276 * SACK with no delay. If a packet arrives with duplicate 3277 * DATA chunk(s) bundled with new DATA chunks, the endpoint 3278 * MAY immediately send a SACK. Normally receipt of duplicate 3279 * DATA chunks will occur when the original SACK chunk was lost 3280 * and the peer's RTO has expired. The duplicate TSN number(s) 3281 * SHOULD be reported in the SACK as duplicate. 3282 */ 3283 /* In our case, we split the MAY SACK advice up whether or not 3284 * the last chunk is a duplicate.' 3285 */ 3286 if (chunk->end_of_packet) 3287 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3288 return SCTP_DISPOSITION_DISCARD; 3289 3290discard_noforce: 3291 if (chunk->end_of_packet) 3292 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3293 3294 return SCTP_DISPOSITION_DISCARD; 3295} 3296 3297/* 3298 * sctp_sf_eat_data_fast_4_4 3299 * 3300 * Section: 4 (4) 3301 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 3302 * DATA chunks without delay. 3303 * 3304 * Verification Tag: 8.5 Verification Tag [Normal verification] 3305 * Inputs 3306 * (endpoint, asoc, chunk) 3307 * 3308 * Outputs 3309 * (asoc, reply_msg, msg_up, timers, counters) 3310 * 3311 * The return value is the disposition of the chunk. 3312 */ 3313enum sctp_disposition sctp_sf_eat_data_fast_4_4( 3314 struct net *net, 3315 const struct sctp_endpoint *ep, 3316 const struct sctp_association *asoc, 3317 const union sctp_subtype type, 3318 void *arg, 3319 struct sctp_cmd_seq *commands) 3320{ 3321 struct sctp_chunk *chunk = arg; 3322 int error; 3323 3324 if (!sctp_vtag_verify(chunk, asoc)) { 3325 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3326 SCTP_NULL()); 3327 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3328 } 3329 3330 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream))) 3331 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3332 commands); 3333 3334 error = sctp_eat_data(asoc, chunk, commands); 3335 switch (error) { 3336 case SCTP_IERROR_NO_ERROR: 3337 case SCTP_IERROR_HIGH_TSN: 3338 case SCTP_IERROR_DUP_TSN: 3339 case SCTP_IERROR_IGNORE_TSN: 3340 case SCTP_IERROR_BAD_STREAM: 3341 break; 3342 case SCTP_IERROR_NO_DATA: 3343 return SCTP_DISPOSITION_ABORT; 3344 case SCTP_IERROR_PROTO_VIOLATION: 3345 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3346 (u8 *)chunk->subh.data_hdr, 3347 sctp_datahdr_len(&asoc->stream)); 3348 default: 3349 BUG(); 3350 } 3351 3352 /* Go a head and force a SACK, since we are shutting down. */ 3353 3354 /* Implementor's Guide. 3355 * 3356 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3357 * respond to each received packet containing one or more DATA chunk(s) 3358 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3359 */ 3360 if (chunk->end_of_packet) { 3361 /* We must delay the chunk creation since the cumulative 3362 * TSN has not been updated yet. 3363 */ 3364 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3365 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3366 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3367 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3368 } 3369 3370 return SCTP_DISPOSITION_CONSUME; 3371} 3372 3373/* 3374 * Section: 6.2 Processing a Received SACK 3375 * D) Any time a SACK arrives, the endpoint performs the following: 3376 * 3377 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 3378 * then drop the SACK. Since Cumulative TSN Ack is monotonically 3379 * increasing, a SACK whose Cumulative TSN Ack is less than the 3380 * Cumulative TSN Ack Point indicates an out-of-order SACK. 3381 * 3382 * ii) Set rwnd equal to the newly received a_rwnd minus the number 3383 * of bytes still outstanding after processing the Cumulative TSN Ack 3384 * and the Gap Ack Blocks. 3385 * 3386 * iii) If the SACK is missing a TSN that was previously 3387 * acknowledged via a Gap Ack Block (e.g., the data receiver 3388 * reneged on the data), then mark the corresponding DATA chunk 3389 * as available for retransmit: Mark it as missing for fast 3390 * retransmit as described in Section 7.2.4 and if no retransmit 3391 * timer is running for the destination address to which the DATA 3392 * chunk was originally transmitted, then T3-rtx is started for 3393 * that destination address. 3394 * 3395 * Verification Tag: 8.5 Verification Tag [Normal verification] 3396 * 3397 * Inputs 3398 * (endpoint, asoc, chunk) 3399 * 3400 * Outputs 3401 * (asoc, reply_msg, msg_up, timers, counters) 3402 * 3403 * The return value is the disposition of the chunk. 3404 */ 3405enum sctp_disposition sctp_sf_eat_sack_6_2(struct net *net, 3406 const struct sctp_endpoint *ep, 3407 const struct sctp_association *asoc, 3408 const union sctp_subtype type, 3409 void *arg, 3410 struct sctp_cmd_seq *commands) 3411{ 3412 struct sctp_chunk *chunk = arg; 3413 struct sctp_sackhdr *sackh; 3414 __u32 ctsn; 3415 3416 if (!sctp_vtag_verify(chunk, asoc)) 3417 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3418 3419 /* Make sure that the SACK chunk has a valid length. */ 3420 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_sack_chunk))) 3421 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3422 commands); 3423 3424 /* Pull the SACK chunk from the data buffer */ 3425 sackh = sctp_sm_pull_sack(chunk); 3426 /* Was this a bogus SACK? */ 3427 if (!sackh) 3428 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3429 chunk->subh.sack_hdr = sackh; 3430 ctsn = ntohl(sackh->cum_tsn_ack); 3431 3432 /* If Cumulative TSN Ack beyond the max tsn currently 3433 * send, terminating the association and respond to the 3434 * sender with an ABORT. 3435 */ 3436 if (TSN_lte(asoc->next_tsn, ctsn)) 3437 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 3438 3439 trace_sctp_probe(ep, asoc, chunk); 3440 3441 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 3442 * Ack Point, then drop the SACK. Since Cumulative TSN 3443 * Ack is monotonically increasing, a SACK whose 3444 * Cumulative TSN Ack is less than the Cumulative TSN Ack 3445 * Point indicates an out-of-order SACK. 3446 */ 3447 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 3448 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 3449 asoc->ctsn_ack_point); 3450 3451 return SCTP_DISPOSITION_DISCARD; 3452 } 3453 3454 /* Return this SACK for further processing. */ 3455 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk)); 3456 3457 /* Note: We do the rest of the work on the PROCESS_SACK 3458 * sideeffect. 3459 */ 3460 return SCTP_DISPOSITION_CONSUME; 3461} 3462 3463/* 3464 * Generate an ABORT in response to a packet. 3465 * 3466 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 3467 * 3468 * 8) The receiver should respond to the sender of the OOTB packet with 3469 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3470 * MUST fill in the Verification Tag field of the outbound packet 3471 * with the value found in the Verification Tag field of the OOTB 3472 * packet and set the T-bit in the Chunk Flags to indicate that the 3473 * Verification Tag is reflected. After sending this ABORT, the 3474 * receiver of the OOTB packet shall discard the OOTB packet and take 3475 * no further action. 3476 * 3477 * Verification Tag: 3478 * 3479 * The return value is the disposition of the chunk. 3480*/ 3481static enum sctp_disposition sctp_sf_tabort_8_4_8( 3482 struct net *net, 3483 const struct sctp_endpoint *ep, 3484 const struct sctp_association *asoc, 3485 const union sctp_subtype type, 3486 void *arg, 3487 struct sctp_cmd_seq *commands) 3488{ 3489 struct sctp_packet *packet = NULL; 3490 struct sctp_chunk *chunk = arg; 3491 struct sctp_chunk *abort; 3492 3493 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3494 if (!packet) 3495 return SCTP_DISPOSITION_NOMEM; 3496 3497 /* Make an ABORT. The T bit will be set if the asoc 3498 * is NULL. 3499 */ 3500 abort = sctp_make_abort(asoc, chunk, 0); 3501 if (!abort) { 3502 sctp_ootb_pkt_free(packet); 3503 return SCTP_DISPOSITION_NOMEM; 3504 } 3505 3506 /* Reflect vtag if T-Bit is set */ 3507 if (sctp_test_T_bit(abort)) 3508 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3509 3510 /* Set the skb to the belonging sock for accounting. */ 3511 abort->skb->sk = ep->base.sk; 3512 3513 sctp_packet_append_chunk(packet, abort); 3514 3515 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(packet)); 3516 3517 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3518 3519 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3520 return SCTP_DISPOSITION_CONSUME; 3521} 3522 3523/* Handling of SCTP Packets Containing an INIT Chunk Matching an 3524 * Existing Associations when the UDP encap port is incorrect. 3525 * 3526 * From Section 4 at draft-tuexen-tsvwg-sctp-udp-encaps-cons-03. 3527 */ 3528static enum sctp_disposition sctp_sf_new_encap_port( 3529 struct net *net, 3530 const struct sctp_endpoint *ep, 3531 const struct sctp_association *asoc, 3532 const union sctp_subtype type, 3533 void *arg, 3534 struct sctp_cmd_seq *commands) 3535{ 3536 struct sctp_packet *packet = NULL; 3537 struct sctp_chunk *chunk = arg; 3538 struct sctp_chunk *abort; 3539 3540 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3541 if (!packet) 3542 return SCTP_DISPOSITION_NOMEM; 3543 3544 abort = sctp_make_new_encap_port(asoc, chunk); 3545 if (!abort) { 3546 sctp_ootb_pkt_free(packet); 3547 return SCTP_DISPOSITION_NOMEM; 3548 } 3549 3550 abort->skb->sk = ep->base.sk; 3551 3552 sctp_packet_append_chunk(packet, abort); 3553 3554 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3555 SCTP_PACKET(packet)); 3556 3557 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3558 3559 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3560 return SCTP_DISPOSITION_CONSUME; 3561} 3562 3563/* 3564 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 3565 * event as ULP notification for each cause included in the chunk. 3566 * 3567 * API 5.3.1.3 - SCTP_REMOTE_ERROR 3568 * 3569 * The return value is the disposition of the chunk. 3570*/ 3571enum sctp_disposition sctp_sf_operr_notify(struct net *net, 3572 const struct sctp_endpoint *ep, 3573 const struct sctp_association *asoc, 3574 const union sctp_subtype type, 3575 void *arg, 3576 struct sctp_cmd_seq *commands) 3577{ 3578 struct sctp_chunk *chunk = arg; 3579 struct sctp_errhdr *err; 3580 3581 if (!sctp_vtag_verify(chunk, asoc)) 3582 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3583 3584 /* Make sure that the ERROR chunk has a valid length. */ 3585 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk))) 3586 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3587 commands); 3588 sctp_walk_errors(err, chunk->chunk_hdr); 3589 if ((void *)err != (void *)chunk->chunk_end) 3590 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3591 (void *)err, commands); 3592 3593 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 3594 SCTP_CHUNK(chunk)); 3595 3596 return SCTP_DISPOSITION_CONSUME; 3597} 3598 3599/* 3600 * Process an inbound SHUTDOWN ACK. 3601 * 3602 * From Section 9.2: 3603 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3604 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 3605 * peer, and remove all record of the association. 3606 * 3607 * The return value is the disposition. 3608 */ 3609enum sctp_disposition sctp_sf_do_9_2_final(struct net *net, 3610 const struct sctp_endpoint *ep, 3611 const struct sctp_association *asoc, 3612 const union sctp_subtype type, 3613 void *arg, 3614 struct sctp_cmd_seq *commands) 3615{ 3616 struct sctp_chunk *chunk = arg; 3617 struct sctp_chunk *reply; 3618 struct sctp_ulpevent *ev; 3619 3620 if (!sctp_vtag_verify(chunk, asoc)) 3621 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3622 3623 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3624 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3625 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3626 commands); 3627 /* 10.2 H) SHUTDOWN COMPLETE notification 3628 * 3629 * When SCTP completes the shutdown procedures (section 9.2) this 3630 * notification is passed to the upper layer. 3631 */ 3632 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3633 0, 0, 0, NULL, GFP_ATOMIC); 3634 if (!ev) 3635 goto nomem; 3636 3637 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3638 reply = sctp_make_shutdown_complete(asoc, chunk); 3639 if (!reply) 3640 goto nomem_chunk; 3641 3642 /* Do all the commands now (after allocation), so that we 3643 * have consistent state if memory allocation fails 3644 */ 3645 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3646 3647 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3648 * stop the T2-shutdown timer, 3649 */ 3650 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3651 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3652 3653 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3654 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3655 3656 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3657 SCTP_STATE(SCTP_STATE_CLOSED)); 3658 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 3659 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3660 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3661 3662 /* ...and remove all record of the association. */ 3663 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3664 return SCTP_DISPOSITION_DELETE_TCB; 3665 3666nomem_chunk: 3667 sctp_ulpevent_free(ev); 3668nomem: 3669 return SCTP_DISPOSITION_NOMEM; 3670} 3671 3672/* 3673 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3674 * 3675 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3676 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3677 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3678 * packet must fill in the Verification Tag field of the outbound 3679 * packet with the Verification Tag received in the SHUTDOWN ACK and 3680 * set the T-bit in the Chunk Flags to indicate that the Verification 3681 * Tag is reflected. 3682 * 3683 * 8) The receiver should respond to the sender of the OOTB packet with 3684 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3685 * MUST fill in the Verification Tag field of the outbound packet 3686 * with the value found in the Verification Tag field of the OOTB 3687 * packet and set the T-bit in the Chunk Flags to indicate that the 3688 * Verification Tag is reflected. After sending this ABORT, the 3689 * receiver of the OOTB packet shall discard the OOTB packet and take 3690 * no further action. 3691 */ 3692enum sctp_disposition sctp_sf_ootb(struct net *net, 3693 const struct sctp_endpoint *ep, 3694 const struct sctp_association *asoc, 3695 const union sctp_subtype type, 3696 void *arg, struct sctp_cmd_seq *commands) 3697{ 3698 struct sctp_chunk *chunk = arg; 3699 struct sk_buff *skb = chunk->skb; 3700 struct sctp_chunkhdr *ch; 3701 struct sctp_errhdr *err; 3702 int ootb_cookie_ack = 0; 3703 int ootb_shut_ack = 0; 3704 __u8 *ch_end; 3705 3706 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3707 3708 if (asoc && !sctp_vtag_verify(chunk, asoc)) 3709 asoc = NULL; 3710 3711 ch = (struct sctp_chunkhdr *)chunk->chunk_hdr; 3712 do { 3713 /* Report violation if the chunk is less then minimal */ 3714 if (ntohs(ch->length) < sizeof(*ch)) 3715 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3716 commands); 3717 3718 /* Report violation if chunk len overflows */ 3719 ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length)); 3720 if (ch_end > skb_tail_pointer(skb)) 3721 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3722 commands); 3723 3724 /* Now that we know we at least have a chunk header, 3725 * do things that are type appropriate. 3726 */ 3727 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3728 ootb_shut_ack = 1; 3729 3730 /* RFC 2960, Section 3.3.7 3731 * Moreover, under any circumstances, an endpoint that 3732 * receives an ABORT MUST NOT respond to that ABORT by 3733 * sending an ABORT of its own. 3734 */ 3735 if (SCTP_CID_ABORT == ch->type) 3736 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3737 3738 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR 3739 * or a COOKIE ACK the SCTP Packet should be silently 3740 * discarded. 3741 */ 3742 3743 if (SCTP_CID_COOKIE_ACK == ch->type) 3744 ootb_cookie_ack = 1; 3745 3746 if (SCTP_CID_ERROR == ch->type) { 3747 sctp_walk_errors(err, ch) { 3748 if (SCTP_ERROR_STALE_COOKIE == err->cause) { 3749 ootb_cookie_ack = 1; 3750 break; 3751 } 3752 } 3753 } 3754 3755 ch = (struct sctp_chunkhdr *)ch_end; 3756 } while (ch_end + sizeof(*ch) < skb_tail_pointer(skb)); 3757 3758 if (ootb_shut_ack) 3759 return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands); 3760 else if (ootb_cookie_ack) 3761 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3762 else 3763 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 3764} 3765 3766/* 3767 * Handle an "Out of the blue" SHUTDOWN ACK. 3768 * 3769 * Section: 8.4 5, sctpimpguide 2.41. 3770 * 3771 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3772 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3773 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3774 * packet must fill in the Verification Tag field of the outbound 3775 * packet with the Verification Tag received in the SHUTDOWN ACK and 3776 * set the T-bit in the Chunk Flags to indicate that the Verification 3777 * Tag is reflected. 3778 * 3779 * Inputs 3780 * (endpoint, asoc, type, arg, commands) 3781 * 3782 * Outputs 3783 * (enum sctp_disposition) 3784 * 3785 * The return value is the disposition of the chunk. 3786 */ 3787static enum sctp_disposition sctp_sf_shut_8_4_5( 3788 struct net *net, 3789 const struct sctp_endpoint *ep, 3790 const struct sctp_association *asoc, 3791 const union sctp_subtype type, 3792 void *arg, 3793 struct sctp_cmd_seq *commands) 3794{ 3795 struct sctp_packet *packet = NULL; 3796 struct sctp_chunk *chunk = arg; 3797 struct sctp_chunk *shut; 3798 3799 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3800 if (!packet) 3801 return SCTP_DISPOSITION_NOMEM; 3802 3803 /* Make an SHUTDOWN_COMPLETE. 3804 * The T bit will be set if the asoc is NULL. 3805 */ 3806 shut = sctp_make_shutdown_complete(asoc, chunk); 3807 if (!shut) { 3808 sctp_ootb_pkt_free(packet); 3809 return SCTP_DISPOSITION_NOMEM; 3810 } 3811 3812 /* Reflect vtag if T-Bit is set */ 3813 if (sctp_test_T_bit(shut)) 3814 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3815 3816 /* Set the skb to the belonging sock for accounting. */ 3817 shut->skb->sk = ep->base.sk; 3818 3819 sctp_packet_append_chunk(packet, shut); 3820 3821 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3822 SCTP_PACKET(packet)); 3823 3824 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3825 3826 /* We need to discard the rest of the packet to prevent 3827 * potential boomming attacks from additional bundled chunks. 3828 * This is documented in SCTP Threats ID. 3829 */ 3830 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3831} 3832 3833/* 3834 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3835 * 3836 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3837 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3838 * procedures in section 8.4 SHOULD be followed, in other words it 3839 * should be treated as an Out Of The Blue packet. 3840 * [This means that we do NOT check the Verification Tag on these 3841 * chunks. --piggy ] 3842 * 3843 */ 3844enum sctp_disposition sctp_sf_do_8_5_1_E_sa(struct net *net, 3845 const struct sctp_endpoint *ep, 3846 const struct sctp_association *asoc, 3847 const union sctp_subtype type, 3848 void *arg, 3849 struct sctp_cmd_seq *commands) 3850{ 3851 struct sctp_chunk *chunk = arg; 3852 3853 if (!sctp_vtag_verify(chunk, asoc)) 3854 asoc = NULL; 3855 3856 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3857 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3858 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3859 commands); 3860 3861 /* Although we do have an association in this case, it corresponds 3862 * to a restarted association. So the packet is treated as an OOTB 3863 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3864 * called with a NULL association. 3865 */ 3866 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3867 3868 return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands); 3869} 3870 3871/* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3872enum sctp_disposition sctp_sf_do_asconf(struct net *net, 3873 const struct sctp_endpoint *ep, 3874 const struct sctp_association *asoc, 3875 const union sctp_subtype type, 3876 void *arg, 3877 struct sctp_cmd_seq *commands) 3878{ 3879 struct sctp_paramhdr *err_param = NULL; 3880 struct sctp_chunk *asconf_ack = NULL; 3881 struct sctp_chunk *chunk = arg; 3882 struct sctp_addiphdr *hdr; 3883 __u32 serial; 3884 3885 if (!sctp_vtag_verify(chunk, asoc)) { 3886 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3887 SCTP_NULL()); 3888 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3889 } 3890 3891 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3892 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_addip_chunk))) 3893 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3894 commands); 3895 3896 /* ADD-IP: Section 4.1.1 3897 * This chunk MUST be sent in an authenticated way by using 3898 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3899 * is received unauthenticated it MUST be silently discarded as 3900 * described in [I-D.ietf-tsvwg-sctp-auth]. 3901 */ 3902 if (!asoc->peer.asconf_capable || 3903 (!net->sctp.addip_noauth && !chunk->auth)) 3904 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3905 3906 hdr = (struct sctp_addiphdr *)chunk->skb->data; 3907 serial = ntohl(hdr->serial); 3908 3909 /* Verify the ASCONF chunk before processing it. */ 3910 if (!sctp_verify_asconf(asoc, chunk, true, &err_param)) 3911 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3912 (void *)err_param, commands); 3913 3914 /* ADDIP 5.2 E1) Compare the value of the serial number to the value 3915 * the endpoint stored in a new association variable 3916 * 'Peer-Serial-Number'. 3917 */ 3918 if (serial == asoc->peer.addip_serial + 1) { 3919 /* If this is the first instance of ASCONF in the packet, 3920 * we can clean our old ASCONF-ACKs. 3921 */ 3922 if (!chunk->has_asconf) 3923 sctp_assoc_clean_asconf_ack_cache(asoc); 3924 3925 /* ADDIP 5.2 E4) When the Sequence Number matches the next one 3926 * expected, process the ASCONF as described below and after 3927 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to 3928 * the response packet and cache a copy of it (in the event it 3929 * later needs to be retransmitted). 3930 * 3931 * Essentially, do V1-V5. 3932 */ 3933 asconf_ack = sctp_process_asconf((struct sctp_association *) 3934 asoc, chunk); 3935 if (!asconf_ack) 3936 return SCTP_DISPOSITION_NOMEM; 3937 } else if (serial < asoc->peer.addip_serial + 1) { 3938 /* ADDIP 5.2 E2) 3939 * If the value found in the Sequence Number is less than the 3940 * ('Peer- Sequence-Number' + 1), simply skip to the next 3941 * ASCONF, and include in the outbound response packet 3942 * any previously cached ASCONF-ACK response that was 3943 * sent and saved that matches the Sequence Number of the 3944 * ASCONF. Note: It is possible that no cached ASCONF-ACK 3945 * Chunk exists. This will occur when an older ASCONF 3946 * arrives out of order. In such a case, the receiver 3947 * should skip the ASCONF Chunk and not include ASCONF-ACK 3948 * Chunk for that chunk. 3949 */ 3950 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial); 3951 if (!asconf_ack) 3952 return SCTP_DISPOSITION_DISCARD; 3953 3954 /* Reset the transport so that we select the correct one 3955 * this time around. This is to make sure that we don't 3956 * accidentally use a stale transport that's been removed. 3957 */ 3958 asconf_ack->transport = NULL; 3959 } else { 3960 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since 3961 * it must be either a stale packet or from an attacker. 3962 */ 3963 return SCTP_DISPOSITION_DISCARD; 3964 } 3965 3966 /* ADDIP 5.2 E6) The destination address of the SCTP packet 3967 * containing the ASCONF-ACK Chunks MUST be the source address of 3968 * the SCTP packet that held the ASCONF Chunks. 3969 * 3970 * To do this properly, we'll set the destination address of the chunk 3971 * and at the transmit time, will try look up the transport to use. 3972 * Since ASCONFs may be bundled, the correct transport may not be 3973 * created until we process the entire packet, thus this workaround. 3974 */ 3975 asconf_ack->dest = chunk->source; 3976 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3977 if (asoc->new_transport) { 3978 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, commands); 3979 ((struct sctp_association *)asoc)->new_transport = NULL; 3980 } 3981 3982 return SCTP_DISPOSITION_CONSUME; 3983} 3984 3985static enum sctp_disposition sctp_send_next_asconf( 3986 struct net *net, 3987 const struct sctp_endpoint *ep, 3988 struct sctp_association *asoc, 3989 const union sctp_subtype type, 3990 struct sctp_cmd_seq *commands) 3991{ 3992 struct sctp_chunk *asconf; 3993 struct list_head *entry; 3994 3995 if (list_empty(&asoc->addip_chunk_list)) 3996 return SCTP_DISPOSITION_CONSUME; 3997 3998 entry = asoc->addip_chunk_list.next; 3999 asconf = list_entry(entry, struct sctp_chunk, list); 4000 4001 list_del_init(entry); 4002 sctp_chunk_hold(asconf); 4003 asoc->addip_last_asconf = asconf; 4004 4005 return sctp_sf_do_prm_asconf(net, ep, asoc, type, asconf, commands); 4006} 4007 4008/* 4009 * ADDIP Section 4.3 General rules for address manipulation 4010 * When building TLV parameters for the ASCONF Chunk that will add or 4011 * delete IP addresses the D0 to D13 rules should be applied: 4012 */ 4013enum sctp_disposition sctp_sf_do_asconf_ack(struct net *net, 4014 const struct sctp_endpoint *ep, 4015 const struct sctp_association *asoc, 4016 const union sctp_subtype type, 4017 void *arg, 4018 struct sctp_cmd_seq *commands) 4019{ 4020 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 4021 struct sctp_paramhdr *err_param = NULL; 4022 struct sctp_chunk *asconf_ack = arg; 4023 struct sctp_addiphdr *addip_hdr; 4024 __u32 sent_serial, rcvd_serial; 4025 struct sctp_chunk *abort; 4026 4027 if (!sctp_vtag_verify(asconf_ack, asoc)) { 4028 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4029 SCTP_NULL()); 4030 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4031 } 4032 4033 /* Make sure that the ADDIP chunk has a valid length. */ 4034 if (!sctp_chunk_length_valid(asconf_ack, 4035 sizeof(struct sctp_addip_chunk))) 4036 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4037 commands); 4038 4039 /* ADD-IP, Section 4.1.2: 4040 * This chunk MUST be sent in an authenticated way by using 4041 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 4042 * is received unauthenticated it MUST be silently discarded as 4043 * described in [I-D.ietf-tsvwg-sctp-auth]. 4044 */ 4045 if (!asoc->peer.asconf_capable || 4046 (!net->sctp.addip_noauth && !asconf_ack->auth)) 4047 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4048 4049 addip_hdr = (struct sctp_addiphdr *)asconf_ack->skb->data; 4050 rcvd_serial = ntohl(addip_hdr->serial); 4051 4052 /* Verify the ASCONF-ACK chunk before processing it. */ 4053 if (!sctp_verify_asconf(asoc, asconf_ack, false, &err_param)) 4054 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 4055 (void *)err_param, commands); 4056 4057 if (last_asconf) { 4058 addip_hdr = last_asconf->subh.addip_hdr; 4059 sent_serial = ntohl(addip_hdr->serial); 4060 } else { 4061 sent_serial = asoc->addip_serial - 1; 4062 } 4063 4064 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 4065 * equal to the next serial number to be used but no ASCONF chunk is 4066 * outstanding the endpoint MUST ABORT the association. Note that a 4067 * sequence number is greater than if it is no more than 2^^31-1 4068 * larger than the current sequence number (using serial arithmetic). 4069 */ 4070 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 4071 !(asoc->addip_last_asconf)) { 4072 abort = sctp_make_abort(asoc, asconf_ack, 4073 sizeof(struct sctp_errhdr)); 4074 if (abort) { 4075 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0); 4076 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4077 SCTP_CHUNK(abort)); 4078 } 4079 /* We are going to ABORT, so we might as well stop 4080 * processing the rest of the chunks in the packet. 4081 */ 4082 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4083 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 4084 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4085 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4086 SCTP_ERROR(ECONNABORTED)); 4087 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4088 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 4089 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4090 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4091 return SCTP_DISPOSITION_ABORT; 4092 } 4093 4094 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 4095 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4096 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 4097 4098 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 4099 asconf_ack)) 4100 return sctp_send_next_asconf(net, ep, 4101 (struct sctp_association *)asoc, 4102 type, commands); 4103 4104 abort = sctp_make_abort(asoc, asconf_ack, 4105 sizeof(struct sctp_errhdr)); 4106 if (abort) { 4107 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 4108 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4109 SCTP_CHUNK(abort)); 4110 } 4111 /* We are going to ABORT, so we might as well stop 4112 * processing the rest of the chunks in the packet. 4113 */ 4114 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4115 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4116 SCTP_ERROR(ECONNABORTED)); 4117 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4118 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 4119 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4120 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4121 return SCTP_DISPOSITION_ABORT; 4122 } 4123 4124 return SCTP_DISPOSITION_DISCARD; 4125} 4126 4127/* RE-CONFIG Section 5.2 Upon reception of an RECONF Chunk. */ 4128enum sctp_disposition sctp_sf_do_reconf(struct net *net, 4129 const struct sctp_endpoint *ep, 4130 const struct sctp_association *asoc, 4131 const union sctp_subtype type, 4132 void *arg, 4133 struct sctp_cmd_seq *commands) 4134{ 4135 struct sctp_paramhdr *err_param = NULL; 4136 struct sctp_chunk *chunk = arg; 4137 struct sctp_reconf_chunk *hdr; 4138 union sctp_params param; 4139 4140 if (!sctp_vtag_verify(chunk, asoc)) { 4141 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4142 SCTP_NULL()); 4143 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4144 } 4145 4146 /* Make sure that the RECONF chunk has a valid length. */ 4147 if (!sctp_chunk_length_valid(chunk, sizeof(*hdr))) 4148 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4149 commands); 4150 4151 if (!sctp_verify_reconf(asoc, chunk, &err_param)) 4152 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 4153 (void *)err_param, commands); 4154 4155 hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr; 4156 sctp_walk_params(param, hdr) { 4157 struct sctp_chunk *reply = NULL; 4158 struct sctp_ulpevent *ev = NULL; 4159 4160 if (param.p->type == SCTP_PARAM_RESET_OUT_REQUEST) 4161 reply = sctp_process_strreset_outreq( 4162 (struct sctp_association *)asoc, param, &ev); 4163 else if (param.p->type == SCTP_PARAM_RESET_IN_REQUEST) 4164 reply = sctp_process_strreset_inreq( 4165 (struct sctp_association *)asoc, param, &ev); 4166 else if (param.p->type == SCTP_PARAM_RESET_TSN_REQUEST) 4167 reply = sctp_process_strreset_tsnreq( 4168 (struct sctp_association *)asoc, param, &ev); 4169 else if (param.p->type == SCTP_PARAM_RESET_ADD_OUT_STREAMS) 4170 reply = sctp_process_strreset_addstrm_out( 4171 (struct sctp_association *)asoc, param, &ev); 4172 else if (param.p->type == SCTP_PARAM_RESET_ADD_IN_STREAMS) 4173 reply = sctp_process_strreset_addstrm_in( 4174 (struct sctp_association *)asoc, param, &ev); 4175 else if (param.p->type == SCTP_PARAM_RESET_RESPONSE) 4176 reply = sctp_process_strreset_resp( 4177 (struct sctp_association *)asoc, param, &ev); 4178 4179 if (ev) 4180 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4181 SCTP_ULPEVENT(ev)); 4182 4183 if (reply) 4184 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4185 SCTP_CHUNK(reply)); 4186 } 4187 4188 return SCTP_DISPOSITION_CONSUME; 4189} 4190 4191/* 4192 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 4193 * 4194 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 4195 * its cumulative TSN point to the value carried in the FORWARD TSN 4196 * chunk, and then MUST further advance its cumulative TSN point locally 4197 * if possible. 4198 * After the above processing, the data receiver MUST stop reporting any 4199 * missing TSNs earlier than or equal to the new cumulative TSN point. 4200 * 4201 * Verification Tag: 8.5 Verification Tag [Normal verification] 4202 * 4203 * The return value is the disposition of the chunk. 4204 */ 4205enum sctp_disposition sctp_sf_eat_fwd_tsn(struct net *net, 4206 const struct sctp_endpoint *ep, 4207 const struct sctp_association *asoc, 4208 const union sctp_subtype type, 4209 void *arg, 4210 struct sctp_cmd_seq *commands) 4211{ 4212 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 4213 struct sctp_chunk *chunk = arg; 4214 __u16 len; 4215 __u32 tsn; 4216 4217 if (!sctp_vtag_verify(chunk, asoc)) { 4218 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4219 SCTP_NULL()); 4220 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4221 } 4222 4223 if (!asoc->peer.prsctp_capable) 4224 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4225 4226 /* Make sure that the FORWARD_TSN chunk has valid length. */ 4227 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream))) 4228 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4229 commands); 4230 4231 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 4232 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 4233 len = ntohs(chunk->chunk_hdr->length); 4234 len -= sizeof(struct sctp_chunkhdr); 4235 skb_pull(chunk->skb, len); 4236 4237 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 4238 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 4239 4240 /* The TSN is too high--silently discard the chunk and count on it 4241 * getting retransmitted later. 4242 */ 4243 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 4244 goto discard_noforce; 4245 4246 if (!asoc->stream.si->validate_ftsn(chunk)) 4247 goto discard_noforce; 4248 4249 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 4250 if (len > sctp_ftsnhdr_len(&asoc->stream)) 4251 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 4252 SCTP_CHUNK(chunk)); 4253 4254 /* Count this as receiving DATA. */ 4255 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 4256 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4257 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 4258 } 4259 4260 /* FIXME: For now send a SACK, but DATA processing may 4261 * send another. 4262 */ 4263 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 4264 4265 return SCTP_DISPOSITION_CONSUME; 4266 4267discard_noforce: 4268 return SCTP_DISPOSITION_DISCARD; 4269} 4270 4271enum sctp_disposition sctp_sf_eat_fwd_tsn_fast( 4272 struct net *net, 4273 const struct sctp_endpoint *ep, 4274 const struct sctp_association *asoc, 4275 const union sctp_subtype type, 4276 void *arg, 4277 struct sctp_cmd_seq *commands) 4278{ 4279 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 4280 struct sctp_chunk *chunk = arg; 4281 __u16 len; 4282 __u32 tsn; 4283 4284 if (!sctp_vtag_verify(chunk, asoc)) { 4285 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4286 SCTP_NULL()); 4287 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4288 } 4289 4290 if (!asoc->peer.prsctp_capable) 4291 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4292 4293 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 4294 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream))) 4295 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4296 commands); 4297 4298 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 4299 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 4300 len = ntohs(chunk->chunk_hdr->length); 4301 len -= sizeof(struct sctp_chunkhdr); 4302 skb_pull(chunk->skb, len); 4303 4304 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 4305 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 4306 4307 /* The TSN is too high--silently discard the chunk and count on it 4308 * getting retransmitted later. 4309 */ 4310 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 4311 goto gen_shutdown; 4312 4313 if (!asoc->stream.si->validate_ftsn(chunk)) 4314 goto gen_shutdown; 4315 4316 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 4317 if (len > sctp_ftsnhdr_len(&asoc->stream)) 4318 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 4319 SCTP_CHUNK(chunk)); 4320 4321 /* Go a head and force a SACK, since we are shutting down. */ 4322gen_shutdown: 4323 /* Implementor's Guide. 4324 * 4325 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 4326 * respond to each received packet containing one or more DATA chunk(s) 4327 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 4328 */ 4329 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 4330 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 4331 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4332 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4333 4334 return SCTP_DISPOSITION_CONSUME; 4335} 4336 4337/* 4338 * SCTP-AUTH Section 6.3 Receiving authenticated chunks 4339 * 4340 * The receiver MUST use the HMAC algorithm indicated in the HMAC 4341 * Identifier field. If this algorithm was not specified by the 4342 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk 4343 * during association setup, the AUTH chunk and all chunks after it MUST 4344 * be discarded and an ERROR chunk SHOULD be sent with the error cause 4345 * defined in Section 4.1. 4346 * 4347 * If an endpoint with no shared key receives a Shared Key Identifier 4348 * other than 0, it MUST silently discard all authenticated chunks. If 4349 * the endpoint has at least one endpoint pair shared key for the peer, 4350 * it MUST use the key specified by the Shared Key Identifier if a 4351 * key has been configured for that Shared Key Identifier. If no 4352 * endpoint pair shared key has been configured for that Shared Key 4353 * Identifier, all authenticated chunks MUST be silently discarded. 4354 * 4355 * Verification Tag: 8.5 Verification Tag [Normal verification] 4356 * 4357 * The return value is the disposition of the chunk. 4358 */ 4359static enum sctp_ierror sctp_sf_authenticate( 4360 const struct sctp_association *asoc, 4361 struct sctp_chunk *chunk) 4362{ 4363 struct sctp_shared_key *sh_key = NULL; 4364 struct sctp_authhdr *auth_hdr; 4365 __u8 *save_digest, *digest; 4366 const struct sctp_hmac *hmac; 4367 unsigned int sig_len; 4368 __u16 key_id; 4369 4370 /* Pull in the auth header, so we can do some more verification */ 4371 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4372 chunk->subh.auth_hdr = auth_hdr; 4373 skb_pull(chunk->skb, sizeof(*auth_hdr)); 4374 4375 /* Make sure that we support the HMAC algorithm from the auth 4376 * chunk. 4377 */ 4378 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id)) 4379 return SCTP_IERROR_AUTH_BAD_HMAC; 4380 4381 /* Make sure that the provided shared key identifier has been 4382 * configured 4383 */ 4384 key_id = ntohs(auth_hdr->shkey_id); 4385 if (key_id != asoc->active_key_id) { 4386 sh_key = sctp_auth_get_shkey(asoc, key_id); 4387 if (!sh_key) 4388 return SCTP_IERROR_AUTH_BAD_KEYID; 4389 } 4390 4391 /* Make sure that the length of the signature matches what 4392 * we expect. 4393 */ 4394 sig_len = ntohs(chunk->chunk_hdr->length) - 4395 sizeof(struct sctp_auth_chunk); 4396 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id)); 4397 if (sig_len != hmac->hmac_len) 4398 return SCTP_IERROR_PROTO_VIOLATION; 4399 4400 /* Now that we've done validation checks, we can compute and 4401 * verify the hmac. The steps involved are: 4402 * 1. Save the digest from the chunk. 4403 * 2. Zero out the digest in the chunk. 4404 * 3. Compute the new digest 4405 * 4. Compare saved and new digests. 4406 */ 4407 digest = (u8 *)(auth_hdr + 1); 4408 skb_pull(chunk->skb, sig_len); 4409 4410 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC); 4411 if (!save_digest) 4412 goto nomem; 4413 4414 memset(digest, 0, sig_len); 4415 4416 sctp_auth_calculate_hmac(asoc, chunk->skb, 4417 (struct sctp_auth_chunk *)chunk->chunk_hdr, 4418 sh_key, GFP_ATOMIC); 4419 4420 /* Discard the packet if the digests do not match */ 4421 if (crypto_memneq(save_digest, digest, sig_len)) { 4422 kfree(save_digest); 4423 return SCTP_IERROR_BAD_SIG; 4424 } 4425 4426 kfree(save_digest); 4427 chunk->auth = 1; 4428 4429 return SCTP_IERROR_NO_ERROR; 4430nomem: 4431 return SCTP_IERROR_NOMEM; 4432} 4433 4434enum sctp_disposition sctp_sf_eat_auth(struct net *net, 4435 const struct sctp_endpoint *ep, 4436 const struct sctp_association *asoc, 4437 const union sctp_subtype type, 4438 void *arg, struct sctp_cmd_seq *commands) 4439{ 4440 struct sctp_chunk *chunk = arg; 4441 struct sctp_authhdr *auth_hdr; 4442 struct sctp_chunk *err_chunk; 4443 enum sctp_ierror error; 4444 4445 /* Make sure that the peer has AUTH capable */ 4446 if (!asoc->peer.auth_capable) 4447 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4448 4449 if (!sctp_vtag_verify(chunk, asoc)) { 4450 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4451 SCTP_NULL()); 4452 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4453 } 4454 4455 /* Make sure that the AUTH chunk has valid length. */ 4456 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk))) 4457 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4458 commands); 4459 4460 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4461 error = sctp_sf_authenticate(asoc, chunk); 4462 switch (error) { 4463 case SCTP_IERROR_AUTH_BAD_HMAC: 4464 /* Generate the ERROR chunk and discard the rest 4465 * of the packet 4466 */ 4467 err_chunk = sctp_make_op_error(asoc, chunk, 4468 SCTP_ERROR_UNSUP_HMAC, 4469 &auth_hdr->hmac_id, 4470 sizeof(__u16), 0); 4471 if (err_chunk) { 4472 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4473 SCTP_CHUNK(err_chunk)); 4474 } 4475 fallthrough; 4476 case SCTP_IERROR_AUTH_BAD_KEYID: 4477 case SCTP_IERROR_BAD_SIG: 4478 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4479 4480 case SCTP_IERROR_PROTO_VIOLATION: 4481 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4482 commands); 4483 4484 case SCTP_IERROR_NOMEM: 4485 return SCTP_DISPOSITION_NOMEM; 4486 4487 default: /* Prevent gcc warnings */ 4488 break; 4489 } 4490 4491 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) { 4492 struct sctp_ulpevent *ev; 4493 4494 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id), 4495 SCTP_AUTH_NEW_KEY, GFP_ATOMIC); 4496 4497 if (!ev) 4498 return SCTP_DISPOSITION_NOMEM; 4499 4500 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4501 SCTP_ULPEVENT(ev)); 4502 } 4503 4504 return SCTP_DISPOSITION_CONSUME; 4505} 4506 4507/* 4508 * Process an unknown chunk. 4509 * 4510 * Section: 3.2. Also, 2.1 in the implementor's guide. 4511 * 4512 * Chunk Types are encoded such that the highest-order two bits specify 4513 * the action that must be taken if the processing endpoint does not 4514 * recognize the Chunk Type. 4515 * 4516 * 00 - Stop processing this SCTP packet and discard it, do not process 4517 * any further chunks within it. 4518 * 4519 * 01 - Stop processing this SCTP packet and discard it, do not process 4520 * any further chunks within it, and report the unrecognized 4521 * chunk in an 'Unrecognized Chunk Type'. 4522 * 4523 * 10 - Skip this chunk and continue processing. 4524 * 4525 * 11 - Skip this chunk and continue processing, but report in an ERROR 4526 * Chunk using the 'Unrecognized Chunk Type' cause of error. 4527 * 4528 * The return value is the disposition of the chunk. 4529 */ 4530enum sctp_disposition sctp_sf_unk_chunk(struct net *net, 4531 const struct sctp_endpoint *ep, 4532 const struct sctp_association *asoc, 4533 const union sctp_subtype type, 4534 void *arg, 4535 struct sctp_cmd_seq *commands) 4536{ 4537 struct sctp_chunk *unk_chunk = arg; 4538 struct sctp_chunk *err_chunk; 4539 struct sctp_chunkhdr *hdr; 4540 4541 pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk); 4542 4543 if (!sctp_vtag_verify(unk_chunk, asoc)) 4544 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4545 4546 /* Make sure that the chunk has a valid length. 4547 * Since we don't know the chunk type, we use a general 4548 * chunkhdr structure to make a comparison. 4549 */ 4550 if (!sctp_chunk_length_valid(unk_chunk, sizeof(*hdr))) 4551 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4552 commands); 4553 4554 switch (type.chunk & SCTP_CID_ACTION_MASK) { 4555 case SCTP_CID_ACTION_DISCARD: 4556 /* Discard the packet. */ 4557 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4558 case SCTP_CID_ACTION_DISCARD_ERR: 4559 /* Generate an ERROR chunk as response. */ 4560 hdr = unk_chunk->chunk_hdr; 4561 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4562 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4563 SCTP_PAD4(ntohs(hdr->length)), 4564 0); 4565 if (err_chunk) { 4566 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4567 SCTP_CHUNK(err_chunk)); 4568 } 4569 4570 /* Discard the packet. */ 4571 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4572 return SCTP_DISPOSITION_CONSUME; 4573 case SCTP_CID_ACTION_SKIP: 4574 /* Skip the chunk. */ 4575 return SCTP_DISPOSITION_DISCARD; 4576 case SCTP_CID_ACTION_SKIP_ERR: 4577 /* Generate an ERROR chunk as response. */ 4578 hdr = unk_chunk->chunk_hdr; 4579 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4580 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4581 SCTP_PAD4(ntohs(hdr->length)), 4582 0); 4583 if (err_chunk) { 4584 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4585 SCTP_CHUNK(err_chunk)); 4586 } 4587 /* Skip the chunk. */ 4588 return SCTP_DISPOSITION_CONSUME; 4589 default: 4590 break; 4591 } 4592 4593 return SCTP_DISPOSITION_DISCARD; 4594} 4595 4596/* 4597 * Discard the chunk. 4598 * 4599 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 4600 * [Too numerous to mention...] 4601 * Verification Tag: No verification needed. 4602 * Inputs 4603 * (endpoint, asoc, chunk) 4604 * 4605 * Outputs 4606 * (asoc, reply_msg, msg_up, timers, counters) 4607 * 4608 * The return value is the disposition of the chunk. 4609 */ 4610enum sctp_disposition sctp_sf_discard_chunk(struct net *net, 4611 const struct sctp_endpoint *ep, 4612 const struct sctp_association *asoc, 4613 const union sctp_subtype type, 4614 void *arg, 4615 struct sctp_cmd_seq *commands) 4616{ 4617 struct sctp_chunk *chunk = arg; 4618 4619 if (asoc && !sctp_vtag_verify(chunk, asoc)) 4620 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4621 4622 /* Make sure that the chunk has a valid length. 4623 * Since we don't know the chunk type, we use a general 4624 * chunkhdr structure to make a comparison. 4625 */ 4626 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 4627 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4628 commands); 4629 4630 pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk); 4631 4632 return SCTP_DISPOSITION_DISCARD; 4633} 4634 4635/* 4636 * Discard the whole packet. 4637 * 4638 * Section: 8.4 2) 4639 * 4640 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 4641 * silently discard the OOTB packet and take no further action. 4642 * 4643 * Verification Tag: No verification necessary 4644 * 4645 * Inputs 4646 * (endpoint, asoc, chunk) 4647 * 4648 * Outputs 4649 * (asoc, reply_msg, msg_up, timers, counters) 4650 * 4651 * The return value is the disposition of the chunk. 4652 */ 4653enum sctp_disposition sctp_sf_pdiscard(struct net *net, 4654 const struct sctp_endpoint *ep, 4655 const struct sctp_association *asoc, 4656 const union sctp_subtype type, 4657 void *arg, struct sctp_cmd_seq *commands) 4658{ 4659 SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS); 4660 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4661 4662 return SCTP_DISPOSITION_CONSUME; 4663} 4664 4665 4666/* 4667 * The other end is violating protocol. 4668 * 4669 * Section: Not specified 4670 * Verification Tag: Not specified 4671 * Inputs 4672 * (endpoint, asoc, chunk) 4673 * 4674 * Outputs 4675 * (asoc, reply_msg, msg_up, timers, counters) 4676 * 4677 * We simply tag the chunk as a violation. The state machine will log 4678 * the violation and continue. 4679 */ 4680enum sctp_disposition sctp_sf_violation(struct net *net, 4681 const struct sctp_endpoint *ep, 4682 const struct sctp_association *asoc, 4683 const union sctp_subtype type, 4684 void *arg, 4685 struct sctp_cmd_seq *commands) 4686{ 4687 struct sctp_chunk *chunk = arg; 4688 4689 if (!sctp_vtag_verify(chunk, asoc)) 4690 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4691 4692 /* Make sure that the chunk has a valid length. */ 4693 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 4694 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4695 commands); 4696 4697 return SCTP_DISPOSITION_VIOLATION; 4698} 4699 4700/* 4701 * Common function to handle a protocol violation. 4702 */ 4703static enum sctp_disposition sctp_sf_abort_violation( 4704 struct net *net, 4705 const struct sctp_endpoint *ep, 4706 const struct sctp_association *asoc, 4707 void *arg, 4708 struct sctp_cmd_seq *commands, 4709 const __u8 *payload, 4710 const size_t paylen) 4711{ 4712 struct sctp_packet *packet = NULL; 4713 struct sctp_chunk *chunk = arg; 4714 struct sctp_chunk *abort = NULL; 4715 4716 /* SCTP-AUTH, Section 6.3: 4717 * It should be noted that if the receiver wants to tear 4718 * down an association in an authenticated way only, the 4719 * handling of malformed packets should not result in 4720 * tearing down the association. 4721 * 4722 * This means that if we only want to abort associations 4723 * in an authenticated way (i.e AUTH+ABORT), then we 4724 * can't destroy this association just because the packet 4725 * was malformed. 4726 */ 4727 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4728 goto discard; 4729 4730 /* Make the abort chunk. */ 4731 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen); 4732 if (!abort) 4733 goto nomem; 4734 4735 if (asoc) { 4736 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */ 4737 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK && 4738 !asoc->peer.i.init_tag) { 4739 struct sctp_initack_chunk *initack; 4740 4741 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr; 4742 if (!sctp_chunk_length_valid(chunk, sizeof(*initack))) 4743 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T; 4744 else { 4745 unsigned int inittag; 4746 4747 inittag = ntohl(initack->init_hdr.init_tag); 4748 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG, 4749 SCTP_U32(inittag)); 4750 } 4751 } 4752 4753 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4754 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4755 4756 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 4757 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4758 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4759 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4760 SCTP_ERROR(ECONNREFUSED)); 4761 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4762 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4763 } else { 4764 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4765 SCTP_ERROR(ECONNABORTED)); 4766 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4767 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4768 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4769 } 4770 } else { 4771 packet = sctp_ootb_pkt_new(net, asoc, chunk); 4772 4773 if (!packet) 4774 goto nomem_pkt; 4775 4776 if (sctp_test_T_bit(abort)) 4777 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 4778 4779 abort->skb->sk = ep->base.sk; 4780 4781 sctp_packet_append_chunk(packet, abort); 4782 4783 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 4784 SCTP_PACKET(packet)); 4785 4786 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4787 } 4788 4789 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4790 4791discard: 4792 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4793 return SCTP_DISPOSITION_ABORT; 4794 4795nomem_pkt: 4796 sctp_chunk_free(abort); 4797nomem: 4798 return SCTP_DISPOSITION_NOMEM; 4799} 4800 4801/* 4802 * Handle a protocol violation when the chunk length is invalid. 4803 * "Invalid" length is identified as smaller than the minimal length a 4804 * given chunk can be. For example, a SACK chunk has invalid length 4805 * if its length is set to be smaller than the size of struct sctp_sack_chunk. 4806 * 4807 * We inform the other end by sending an ABORT with a Protocol Violation 4808 * error code. 4809 * 4810 * Section: Not specified 4811 * Verification Tag: Nothing to do 4812 * Inputs 4813 * (endpoint, asoc, chunk) 4814 * 4815 * Outputs 4816 * (reply_msg, msg_up, counters) 4817 * 4818 * Generate an ABORT chunk and terminate the association. 4819 */ 4820static enum sctp_disposition sctp_sf_violation_chunklen( 4821 struct net *net, 4822 const struct sctp_endpoint *ep, 4823 const struct sctp_association *asoc, 4824 const union sctp_subtype type, 4825 void *arg, 4826 struct sctp_cmd_seq *commands) 4827{ 4828 static const char err_str[] = "The following chunk had invalid length:"; 4829 4830 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4831 sizeof(err_str)); 4832} 4833 4834/* 4835 * Handle a protocol violation when the parameter length is invalid. 4836 * If the length is smaller than the minimum length of a given parameter, 4837 * or accumulated length in multi parameters exceeds the end of the chunk, 4838 * the length is considered as invalid. 4839 */ 4840static enum sctp_disposition sctp_sf_violation_paramlen( 4841 struct net *net, 4842 const struct sctp_endpoint *ep, 4843 const struct sctp_association *asoc, 4844 const union sctp_subtype type, 4845 void *arg, void *ext, 4846 struct sctp_cmd_seq *commands) 4847{ 4848 struct sctp_paramhdr *param = ext; 4849 struct sctp_chunk *abort = NULL; 4850 struct sctp_chunk *chunk = arg; 4851 4852 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4853 goto discard; 4854 4855 /* Make the abort chunk. */ 4856 abort = sctp_make_violation_paramlen(asoc, chunk, param); 4857 if (!abort) 4858 goto nomem; 4859 4860 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4861 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4862 4863 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4864 SCTP_ERROR(ECONNABORTED)); 4865 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4866 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4867 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4868 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4869 4870discard: 4871 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4872 return SCTP_DISPOSITION_ABORT; 4873nomem: 4874 return SCTP_DISPOSITION_NOMEM; 4875} 4876 4877/* Handle a protocol violation when the peer trying to advance the 4878 * cumulative tsn ack to a point beyond the max tsn currently sent. 4879 * 4880 * We inform the other end by sending an ABORT with a Protocol Violation 4881 * error code. 4882 */ 4883static enum sctp_disposition sctp_sf_violation_ctsn( 4884 struct net *net, 4885 const struct sctp_endpoint *ep, 4886 const struct sctp_association *asoc, 4887 const union sctp_subtype type, 4888 void *arg, 4889 struct sctp_cmd_seq *commands) 4890{ 4891 static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:"; 4892 4893 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4894 sizeof(err_str)); 4895} 4896 4897/* Handle protocol violation of an invalid chunk bundling. For example, 4898 * when we have an association and we receive bundled INIT-ACK, or 4899 * SHUTDOWN-COMPLETE, our peer is clearly violating the "MUST NOT bundle" 4900 * statement from the specs. Additionally, there might be an attacker 4901 * on the path and we may not want to continue this communication. 4902 */ 4903static enum sctp_disposition sctp_sf_violation_chunk( 4904 struct net *net, 4905 const struct sctp_endpoint *ep, 4906 const struct sctp_association *asoc, 4907 const union sctp_subtype type, 4908 void *arg, 4909 struct sctp_cmd_seq *commands) 4910{ 4911 static const char err_str[] = "The following chunk violates protocol:"; 4912 4913 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4914 sizeof(err_str)); 4915} 4916/*************************************************************************** 4917 * These are the state functions for handling primitive (Section 10) events. 4918 ***************************************************************************/ 4919/* 4920 * sctp_sf_do_prm_asoc 4921 * 4922 * Section: 10.1 ULP-to-SCTP 4923 * B) Associate 4924 * 4925 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 4926 * outbound stream count) 4927 * -> association id [,destination transport addr list] [,outbound stream 4928 * count] 4929 * 4930 * This primitive allows the upper layer to initiate an association to a 4931 * specific peer endpoint. 4932 * 4933 * The peer endpoint shall be specified by one of the transport addresses 4934 * which defines the endpoint (see Section 1.4). If the local SCTP 4935 * instance has not been initialized, the ASSOCIATE is considered an 4936 * error. 4937 * [This is not relevant for the kernel implementation since we do all 4938 * initialization at boot time. It we hadn't initialized we wouldn't 4939 * get anywhere near this code.] 4940 * 4941 * An association id, which is a local handle to the SCTP association, 4942 * will be returned on successful establishment of the association. If 4943 * SCTP is not able to open an SCTP association with the peer endpoint, 4944 * an error is returned. 4945 * [In the kernel implementation, the struct sctp_association needs to 4946 * be created BEFORE causing this primitive to run.] 4947 * 4948 * Other association parameters may be returned, including the 4949 * complete destination transport addresses of the peer as well as the 4950 * outbound stream count of the local endpoint. One of the transport 4951 * address from the returned destination addresses will be selected by 4952 * the local endpoint as default primary path for sending SCTP packets 4953 * to this peer. The returned "destination transport addr list" can 4954 * be used by the ULP to change the default primary path or to force 4955 * sending a packet to a specific transport address. [All of this 4956 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 4957 * function.] 4958 * 4959 * Mandatory attributes: 4960 * 4961 * o local SCTP instance name - obtained from the INITIALIZE operation. 4962 * [This is the argument asoc.] 4963 * o destination transport addr - specified as one of the transport 4964 * addresses of the peer endpoint with which the association is to be 4965 * established. 4966 * [This is asoc->peer.active_path.] 4967 * o outbound stream count - the number of outbound streams the ULP 4968 * would like to open towards this peer endpoint. 4969 * [BUG: This is not currently implemented.] 4970 * Optional attributes: 4971 * 4972 * None. 4973 * 4974 * The return value is a disposition. 4975 */ 4976enum sctp_disposition sctp_sf_do_prm_asoc(struct net *net, 4977 const struct sctp_endpoint *ep, 4978 const struct sctp_association *asoc, 4979 const union sctp_subtype type, 4980 void *arg, 4981 struct sctp_cmd_seq *commands) 4982{ 4983 struct sctp_association *my_asoc; 4984 struct sctp_chunk *repl; 4985 4986 /* The comment below says that we enter COOKIE-WAIT AFTER 4987 * sending the INIT, but that doesn't actually work in our 4988 * implementation... 4989 */ 4990 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4991 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 4992 4993 /* RFC 2960 5.1 Normal Establishment of an Association 4994 * 4995 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 4996 * must provide its Verification Tag (Tag_A) in the Initiate 4997 * Tag field. Tag_A SHOULD be a random number in the range of 4998 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 4999 */ 5000 5001 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 5002 if (!repl) 5003 goto nomem; 5004 5005 /* Choose transport for INIT. */ 5006 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5007 SCTP_CHUNK(repl)); 5008 5009 /* Cast away the const modifier, as we want to just 5010 * rerun it through as a sideffect. 5011 */ 5012 my_asoc = (struct sctp_association *)asoc; 5013 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc)); 5014 5015 /* After sending the INIT, "A" starts the T1-init timer and 5016 * enters the COOKIE-WAIT state. 5017 */ 5018 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5019 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5020 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5021 return SCTP_DISPOSITION_CONSUME; 5022 5023nomem: 5024 return SCTP_DISPOSITION_NOMEM; 5025} 5026 5027/* 5028 * Process the SEND primitive. 5029 * 5030 * Section: 10.1 ULP-to-SCTP 5031 * E) Send 5032 * 5033 * Format: SEND(association id, buffer address, byte count [,context] 5034 * [,stream id] [,life time] [,destination transport address] 5035 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 5036 * -> result 5037 * 5038 * This is the main method to send user data via SCTP. 5039 * 5040 * Mandatory attributes: 5041 * 5042 * o association id - local handle to the SCTP association 5043 * 5044 * o buffer address - the location where the user message to be 5045 * transmitted is stored; 5046 * 5047 * o byte count - The size of the user data in number of bytes; 5048 * 5049 * Optional attributes: 5050 * 5051 * o context - an optional 32 bit integer that will be carried in the 5052 * sending failure notification to the ULP if the transportation of 5053 * this User Message fails. 5054 * 5055 * o stream id - to indicate which stream to send the data on. If not 5056 * specified, stream 0 will be used. 5057 * 5058 * o life time - specifies the life time of the user data. The user data 5059 * will not be sent by SCTP after the life time expires. This 5060 * parameter can be used to avoid efforts to transmit stale 5061 * user messages. SCTP notifies the ULP if the data cannot be 5062 * initiated to transport (i.e. sent to the destination via SCTP's 5063 * send primitive) within the life time variable. However, the 5064 * user data will be transmitted if SCTP has attempted to transmit a 5065 * chunk before the life time expired. 5066 * 5067 * o destination transport address - specified as one of the destination 5068 * transport addresses of the peer endpoint to which this packet 5069 * should be sent. Whenever possible, SCTP should use this destination 5070 * transport address for sending the packets, instead of the current 5071 * primary path. 5072 * 5073 * o unorder flag - this flag, if present, indicates that the user 5074 * would like the data delivered in an unordered fashion to the peer 5075 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 5076 * message). 5077 * 5078 * o no-bundle flag - instructs SCTP not to bundle this user data with 5079 * other outbound DATA chunks. SCTP MAY still bundle even when 5080 * this flag is present, when faced with network congestion. 5081 * 5082 * o payload protocol-id - A 32 bit unsigned integer that is to be 5083 * passed to the peer indicating the type of payload protocol data 5084 * being transmitted. This value is passed as opaque data by SCTP. 5085 * 5086 * The return value is the disposition. 5087 */ 5088enum sctp_disposition sctp_sf_do_prm_send(struct net *net, 5089 const struct sctp_endpoint *ep, 5090 const struct sctp_association *asoc, 5091 const union sctp_subtype type, 5092 void *arg, 5093 struct sctp_cmd_seq *commands) 5094{ 5095 struct sctp_datamsg *msg = arg; 5096 5097 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg)); 5098 return SCTP_DISPOSITION_CONSUME; 5099} 5100 5101/* 5102 * Process the SHUTDOWN primitive. 5103 * 5104 * Section: 10.1: 5105 * C) Shutdown 5106 * 5107 * Format: SHUTDOWN(association id) 5108 * -> result 5109 * 5110 * Gracefully closes an association. Any locally queued user data 5111 * will be delivered to the peer. The association will be terminated only 5112 * after the peer acknowledges all the SCTP packets sent. A success code 5113 * will be returned on successful termination of the association. If 5114 * attempting to terminate the association results in a failure, an error 5115 * code shall be returned. 5116 * 5117 * Mandatory attributes: 5118 * 5119 * o association id - local handle to the SCTP association 5120 * 5121 * Optional attributes: 5122 * 5123 * None. 5124 * 5125 * The return value is the disposition. 5126 */ 5127enum sctp_disposition sctp_sf_do_9_2_prm_shutdown( 5128 struct net *net, 5129 const struct sctp_endpoint *ep, 5130 const struct sctp_association *asoc, 5131 const union sctp_subtype type, 5132 void *arg, 5133 struct sctp_cmd_seq *commands) 5134{ 5135 enum sctp_disposition disposition; 5136 5137 /* From 9.2 Shutdown of an Association 5138 * Upon receipt of the SHUTDOWN primitive from its upper 5139 * layer, the endpoint enters SHUTDOWN-PENDING state and 5140 * remains there until all outstanding data has been 5141 * acknowledged by its peer. The endpoint accepts no new data 5142 * from its upper layer, but retransmits data to the far end 5143 * if necessary to fill gaps. 5144 */ 5145 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5146 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 5147 5148 disposition = SCTP_DISPOSITION_CONSUME; 5149 if (sctp_outq_is_empty(&asoc->outqueue)) { 5150 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 5151 arg, commands); 5152 } 5153 5154 return disposition; 5155} 5156 5157/* 5158 * Process the ABORT primitive. 5159 * 5160 * Section: 10.1: 5161 * C) Abort 5162 * 5163 * Format: Abort(association id [, cause code]) 5164 * -> result 5165 * 5166 * Ungracefully closes an association. Any locally queued user data 5167 * will be discarded and an ABORT chunk is sent to the peer. A success code 5168 * will be returned on successful abortion of the association. If 5169 * attempting to abort the association results in a failure, an error 5170 * code shall be returned. 5171 * 5172 * Mandatory attributes: 5173 * 5174 * o association id - local handle to the SCTP association 5175 * 5176 * Optional attributes: 5177 * 5178 * o cause code - reason of the abort to be passed to the peer 5179 * 5180 * None. 5181 * 5182 * The return value is the disposition. 5183 */ 5184enum sctp_disposition sctp_sf_do_9_1_prm_abort( 5185 struct net *net, 5186 const struct sctp_endpoint *ep, 5187 const struct sctp_association *asoc, 5188 const union sctp_subtype type, 5189 void *arg, 5190 struct sctp_cmd_seq *commands) 5191{ 5192 /* From 9.1 Abort of an Association 5193 * Upon receipt of the ABORT primitive from its upper 5194 * layer, the endpoint enters CLOSED state and 5195 * discard all outstanding data has been 5196 * acknowledged by its peer. The endpoint accepts no new data 5197 * from its upper layer, but retransmits data to the far end 5198 * if necessary to fill gaps. 5199 */ 5200 struct sctp_chunk *abort = arg; 5201 5202 if (abort) 5203 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 5204 5205 /* Even if we can't send the ABORT due to low memory delete the 5206 * TCB. This is a departure from our typical NOMEM handling. 5207 */ 5208 5209 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5210 SCTP_ERROR(ECONNABORTED)); 5211 /* Delete the established association. */ 5212 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5213 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 5214 5215 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5216 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5217 5218 return SCTP_DISPOSITION_ABORT; 5219} 5220 5221/* We tried an illegal operation on an association which is closed. */ 5222enum sctp_disposition sctp_sf_error_closed(struct net *net, 5223 const struct sctp_endpoint *ep, 5224 const struct sctp_association *asoc, 5225 const union sctp_subtype type, 5226 void *arg, 5227 struct sctp_cmd_seq *commands) 5228{ 5229 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 5230 return SCTP_DISPOSITION_CONSUME; 5231} 5232 5233/* We tried an illegal operation on an association which is shutting 5234 * down. 5235 */ 5236enum sctp_disposition sctp_sf_error_shutdown( 5237 struct net *net, 5238 const struct sctp_endpoint *ep, 5239 const struct sctp_association *asoc, 5240 const union sctp_subtype type, 5241 void *arg, 5242 struct sctp_cmd_seq *commands) 5243{ 5244 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, 5245 SCTP_ERROR(-ESHUTDOWN)); 5246 return SCTP_DISPOSITION_CONSUME; 5247} 5248 5249/* 5250 * sctp_cookie_wait_prm_shutdown 5251 * 5252 * Section: 4 Note: 2 5253 * Verification Tag: 5254 * Inputs 5255 * (endpoint, asoc) 5256 * 5257 * The RFC does not explicitly address this issue, but is the route through the 5258 * state table when someone issues a shutdown while in COOKIE_WAIT state. 5259 * 5260 * Outputs 5261 * (timers) 5262 */ 5263enum sctp_disposition sctp_sf_cookie_wait_prm_shutdown( 5264 struct net *net, 5265 const struct sctp_endpoint *ep, 5266 const struct sctp_association *asoc, 5267 const union sctp_subtype type, 5268 void *arg, 5269 struct sctp_cmd_seq *commands) 5270{ 5271 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5272 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5273 5274 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5275 SCTP_STATE(SCTP_STATE_CLOSED)); 5276 5277 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 5278 5279 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 5280 5281 return SCTP_DISPOSITION_DELETE_TCB; 5282} 5283 5284/* 5285 * sctp_cookie_echoed_prm_shutdown 5286 * 5287 * Section: 4 Note: 2 5288 * Verification Tag: 5289 * Inputs 5290 * (endpoint, asoc) 5291 * 5292 * The RFC does not explicitly address this issue, but is the route through the 5293 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 5294 * 5295 * Outputs 5296 * (timers) 5297 */ 5298enum sctp_disposition sctp_sf_cookie_echoed_prm_shutdown( 5299 struct net *net, 5300 const struct sctp_endpoint *ep, 5301 const struct sctp_association *asoc, 5302 const union sctp_subtype type, 5303 void *arg, 5304 struct sctp_cmd_seq *commands) 5305{ 5306 /* There is a single T1 timer, so we should be able to use 5307 * common function with the COOKIE-WAIT state. 5308 */ 5309 return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands); 5310} 5311 5312/* 5313 * sctp_sf_cookie_wait_prm_abort 5314 * 5315 * Section: 4 Note: 2 5316 * Verification Tag: 5317 * Inputs 5318 * (endpoint, asoc) 5319 * 5320 * The RFC does not explicitly address this issue, but is the route through the 5321 * state table when someone issues an abort while in COOKIE_WAIT state. 5322 * 5323 * Outputs 5324 * (timers) 5325 */ 5326enum sctp_disposition sctp_sf_cookie_wait_prm_abort( 5327 struct net *net, 5328 const struct sctp_endpoint *ep, 5329 const struct sctp_association *asoc, 5330 const union sctp_subtype type, 5331 void *arg, 5332 struct sctp_cmd_seq *commands) 5333{ 5334 struct sctp_chunk *abort = arg; 5335 5336 /* Stop T1-init timer */ 5337 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5338 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5339 5340 if (abort) 5341 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 5342 5343 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5344 SCTP_STATE(SCTP_STATE_CLOSED)); 5345 5346 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5347 5348 /* Even if we can't send the ABORT due to low memory delete the 5349 * TCB. This is a departure from our typical NOMEM handling. 5350 */ 5351 5352 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5353 SCTP_ERROR(ECONNREFUSED)); 5354 /* Delete the established association. */ 5355 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5356 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 5357 5358 return SCTP_DISPOSITION_ABORT; 5359} 5360 5361/* 5362 * sctp_sf_cookie_echoed_prm_abort 5363 * 5364 * Section: 4 Note: 3 5365 * Verification Tag: 5366 * Inputs 5367 * (endpoint, asoc) 5368 * 5369 * The RFC does not explcitly address this issue, but is the route through the 5370 * state table when someone issues an abort while in COOKIE_ECHOED state. 5371 * 5372 * Outputs 5373 * (timers) 5374 */ 5375enum sctp_disposition sctp_sf_cookie_echoed_prm_abort( 5376 struct net *net, 5377 const struct sctp_endpoint *ep, 5378 const struct sctp_association *asoc, 5379 const union sctp_subtype type, 5380 void *arg, 5381 struct sctp_cmd_seq *commands) 5382{ 5383 /* There is a single T1 timer, so we should be able to use 5384 * common function with the COOKIE-WAIT state. 5385 */ 5386 return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands); 5387} 5388 5389/* 5390 * sctp_sf_shutdown_pending_prm_abort 5391 * 5392 * Inputs 5393 * (endpoint, asoc) 5394 * 5395 * The RFC does not explicitly address this issue, but is the route through the 5396 * state table when someone issues an abort while in SHUTDOWN-PENDING state. 5397 * 5398 * Outputs 5399 * (timers) 5400 */ 5401enum sctp_disposition sctp_sf_shutdown_pending_prm_abort( 5402 struct net *net, 5403 const struct sctp_endpoint *ep, 5404 const struct sctp_association *asoc, 5405 const union sctp_subtype type, 5406 void *arg, 5407 struct sctp_cmd_seq *commands) 5408{ 5409 /* Stop the T5-shutdown guard timer. */ 5410 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5411 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5412 5413 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5414} 5415 5416/* 5417 * sctp_sf_shutdown_sent_prm_abort 5418 * 5419 * Inputs 5420 * (endpoint, asoc) 5421 * 5422 * The RFC does not explicitly address this issue, but is the route through the 5423 * state table when someone issues an abort while in SHUTDOWN-SENT state. 5424 * 5425 * Outputs 5426 * (timers) 5427 */ 5428enum sctp_disposition sctp_sf_shutdown_sent_prm_abort( 5429 struct net *net, 5430 const struct sctp_endpoint *ep, 5431 const struct sctp_association *asoc, 5432 const union sctp_subtype type, 5433 void *arg, 5434 struct sctp_cmd_seq *commands) 5435{ 5436 /* Stop the T2-shutdown timer. */ 5437 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5438 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5439 5440 /* Stop the T5-shutdown guard timer. */ 5441 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5442 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5443 5444 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5445} 5446 5447/* 5448 * sctp_sf_cookie_echoed_prm_abort 5449 * 5450 * Inputs 5451 * (endpoint, asoc) 5452 * 5453 * The RFC does not explcitly address this issue, but is the route through the 5454 * state table when someone issues an abort while in COOKIE_ECHOED state. 5455 * 5456 * Outputs 5457 * (timers) 5458 */ 5459enum sctp_disposition sctp_sf_shutdown_ack_sent_prm_abort( 5460 struct net *net, 5461 const struct sctp_endpoint *ep, 5462 const struct sctp_association *asoc, 5463 const union sctp_subtype type, 5464 void *arg, 5465 struct sctp_cmd_seq *commands) 5466{ 5467 /* The same T2 timer, so we should be able to use 5468 * common function with the SHUTDOWN-SENT state. 5469 */ 5470 return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands); 5471} 5472 5473/* 5474 * Process the REQUESTHEARTBEAT primitive 5475 * 5476 * 10.1 ULP-to-SCTP 5477 * J) Request Heartbeat 5478 * 5479 * Format: REQUESTHEARTBEAT(association id, destination transport address) 5480 * 5481 * -> result 5482 * 5483 * Instructs the local endpoint to perform a HeartBeat on the specified 5484 * destination transport address of the given association. The returned 5485 * result should indicate whether the transmission of the HEARTBEAT 5486 * chunk to the destination address is successful. 5487 * 5488 * Mandatory attributes: 5489 * 5490 * o association id - local handle to the SCTP association 5491 * 5492 * o destination transport address - the transport address of the 5493 * association on which a heartbeat should be issued. 5494 */ 5495enum sctp_disposition sctp_sf_do_prm_requestheartbeat( 5496 struct net *net, 5497 const struct sctp_endpoint *ep, 5498 const struct sctp_association *asoc, 5499 const union sctp_subtype type, 5500 void *arg, 5501 struct sctp_cmd_seq *commands) 5502{ 5503 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type, 5504 (struct sctp_transport *)arg, commands)) 5505 return SCTP_DISPOSITION_NOMEM; 5506 5507 /* 5508 * RFC 2960 (bis), section 8.3 5509 * 5510 * D) Request an on-demand HEARTBEAT on a specific destination 5511 * transport address of a given association. 5512 * 5513 * The endpoint should increment the respective error counter of 5514 * the destination transport address each time a HEARTBEAT is sent 5515 * to that address and not acknowledged within one RTO. 5516 * 5517 */ 5518 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 5519 SCTP_TRANSPORT(arg)); 5520 return SCTP_DISPOSITION_CONSUME; 5521} 5522 5523/* 5524 * ADDIP Section 4.1 ASCONF Chunk Procedures 5525 * When an endpoint has an ASCONF signaled change to be sent to the 5526 * remote endpoint it should do A1 to A9 5527 */ 5528enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net, 5529 const struct sctp_endpoint *ep, 5530 const struct sctp_association *asoc, 5531 const union sctp_subtype type, 5532 void *arg, 5533 struct sctp_cmd_seq *commands) 5534{ 5535 struct sctp_chunk *chunk = arg; 5536 5537 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5538 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5539 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5540 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5541 return SCTP_DISPOSITION_CONSUME; 5542} 5543 5544/* RE-CONFIG Section 5.1 RECONF Chunk Procedures */ 5545enum sctp_disposition sctp_sf_do_prm_reconf(struct net *net, 5546 const struct sctp_endpoint *ep, 5547 const struct sctp_association *asoc, 5548 const union sctp_subtype type, 5549 void *arg, 5550 struct sctp_cmd_seq *commands) 5551{ 5552 struct sctp_chunk *chunk = arg; 5553 5554 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5555 return SCTP_DISPOSITION_CONSUME; 5556} 5557 5558/* 5559 * Ignore the primitive event 5560 * 5561 * The return value is the disposition of the primitive. 5562 */ 5563enum sctp_disposition sctp_sf_ignore_primitive( 5564 struct net *net, 5565 const struct sctp_endpoint *ep, 5566 const struct sctp_association *asoc, 5567 const union sctp_subtype type, 5568 void *arg, 5569 struct sctp_cmd_seq *commands) 5570{ 5571 pr_debug("%s: primitive type:%d is ignored\n", __func__, 5572 type.primitive); 5573 5574 return SCTP_DISPOSITION_DISCARD; 5575} 5576 5577/*************************************************************************** 5578 * These are the state functions for the OTHER events. 5579 ***************************************************************************/ 5580 5581/* 5582 * When the SCTP stack has no more user data to send or retransmit, this 5583 * notification is given to the user. Also, at the time when a user app 5584 * subscribes to this event, if there is no data to be sent or 5585 * retransmit, the stack will immediately send up this notification. 5586 */ 5587enum sctp_disposition sctp_sf_do_no_pending_tsn( 5588 struct net *net, 5589 const struct sctp_endpoint *ep, 5590 const struct sctp_association *asoc, 5591 const union sctp_subtype type, 5592 void *arg, 5593 struct sctp_cmd_seq *commands) 5594{ 5595 struct sctp_ulpevent *event; 5596 5597 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC); 5598 if (!event) 5599 return SCTP_DISPOSITION_NOMEM; 5600 5601 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event)); 5602 5603 return SCTP_DISPOSITION_CONSUME; 5604} 5605 5606/* 5607 * Start the shutdown negotiation. 5608 * 5609 * From Section 9.2: 5610 * Once all its outstanding data has been acknowledged, the endpoint 5611 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 5612 * TSN Ack field the last sequential TSN it has received from the peer. 5613 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 5614 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 5615 * with the updated last sequential TSN received from its peer. 5616 * 5617 * The return value is the disposition. 5618 */ 5619enum sctp_disposition sctp_sf_do_9_2_start_shutdown( 5620 struct net *net, 5621 const struct sctp_endpoint *ep, 5622 const struct sctp_association *asoc, 5623 const union sctp_subtype type, 5624 void *arg, 5625 struct sctp_cmd_seq *commands) 5626{ 5627 struct sctp_chunk *reply; 5628 5629 /* Once all its outstanding data has been acknowledged, the 5630 * endpoint shall send a SHUTDOWN chunk to its peer including 5631 * in the Cumulative TSN Ack field the last sequential TSN it 5632 * has received from the peer. 5633 */ 5634 reply = sctp_make_shutdown(asoc, arg); 5635 if (!reply) 5636 goto nomem; 5637 5638 /* Set the transport for the SHUTDOWN chunk and the timeout for the 5639 * T2-shutdown timer. 5640 */ 5641 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5642 5643 /* It shall then start the T2-shutdown timer */ 5644 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5645 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5646 5647 /* RFC 4960 Section 9.2 5648 * The sender of the SHUTDOWN MAY also start an overall guard timer 5649 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5650 */ 5651 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5652 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5653 5654 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5655 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5656 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5657 5658 /* and enter the SHUTDOWN-SENT state. */ 5659 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5660 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 5661 5662 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5663 * 5664 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5665 * or SHUTDOWN-ACK. 5666 */ 5667 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5668 5669 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5670 5671 return SCTP_DISPOSITION_CONSUME; 5672 5673nomem: 5674 return SCTP_DISPOSITION_NOMEM; 5675} 5676 5677/* 5678 * Generate a SHUTDOWN ACK now that everything is SACK'd. 5679 * 5680 * From Section 9.2: 5681 * 5682 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5683 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 5684 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 5685 * endpoint must re-send the SHUTDOWN ACK. 5686 * 5687 * The return value is the disposition. 5688 */ 5689enum sctp_disposition sctp_sf_do_9_2_shutdown_ack( 5690 struct net *net, 5691 const struct sctp_endpoint *ep, 5692 const struct sctp_association *asoc, 5693 const union sctp_subtype type, 5694 void *arg, 5695 struct sctp_cmd_seq *commands) 5696{ 5697 struct sctp_chunk *chunk = arg; 5698 struct sctp_chunk *reply; 5699 5700 /* There are 2 ways of getting here: 5701 * 1) called in response to a SHUTDOWN chunk 5702 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 5703 * 5704 * For the case (2), the arg parameter is set to NULL. We need 5705 * to check that we have a chunk before accessing it's fields. 5706 */ 5707 if (chunk) { 5708 if (!sctp_vtag_verify(chunk, asoc)) 5709 return sctp_sf_pdiscard(net, ep, asoc, type, arg, 5710 commands); 5711 5712 /* Make sure that the SHUTDOWN chunk has a valid length. */ 5713 if (!sctp_chunk_length_valid( 5714 chunk, sizeof(struct sctp_shutdown_chunk))) 5715 return sctp_sf_violation_chunklen(net, ep, asoc, type, 5716 arg, commands); 5717 } 5718 5719 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5720 * shall send a SHUTDOWN ACK ... 5721 */ 5722 reply = sctp_make_shutdown_ack(asoc, chunk); 5723 if (!reply) 5724 goto nomem; 5725 5726 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 5727 * the T2-shutdown timer. 5728 */ 5729 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5730 5731 /* and start/restart a T2-shutdown timer of its own, */ 5732 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5733 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5734 5735 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5736 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5737 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5738 5739 /* Enter the SHUTDOWN-ACK-SENT state. */ 5740 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5741 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 5742 5743 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5744 * 5745 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5746 * or SHUTDOWN-ACK. 5747 */ 5748 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5749 5750 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5751 5752 return SCTP_DISPOSITION_CONSUME; 5753 5754nomem: 5755 return SCTP_DISPOSITION_NOMEM; 5756} 5757 5758/* 5759 * Ignore the event defined as other 5760 * 5761 * The return value is the disposition of the event. 5762 */ 5763enum sctp_disposition sctp_sf_ignore_other(struct net *net, 5764 const struct sctp_endpoint *ep, 5765 const struct sctp_association *asoc, 5766 const union sctp_subtype type, 5767 void *arg, 5768 struct sctp_cmd_seq *commands) 5769{ 5770 pr_debug("%s: the event other type:%d is ignored\n", 5771 __func__, type.other); 5772 5773 return SCTP_DISPOSITION_DISCARD; 5774} 5775 5776/************************************************************ 5777 * These are the state functions for handling timeout events. 5778 ************************************************************/ 5779 5780/* 5781 * RTX Timeout 5782 * 5783 * Section: 6.3.3 Handle T3-rtx Expiration 5784 * 5785 * Whenever the retransmission timer T3-rtx expires for a destination 5786 * address, do the following: 5787 * [See below] 5788 * 5789 * The return value is the disposition of the chunk. 5790 */ 5791enum sctp_disposition sctp_sf_do_6_3_3_rtx(struct net *net, 5792 const struct sctp_endpoint *ep, 5793 const struct sctp_association *asoc, 5794 const union sctp_subtype type, 5795 void *arg, 5796 struct sctp_cmd_seq *commands) 5797{ 5798 struct sctp_transport *transport = arg; 5799 5800 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS); 5801 5802 if (asoc->overall_error_count >= asoc->max_retrans) { 5803 if (asoc->peer.zero_window_announced && 5804 asoc->state == SCTP_STATE_SHUTDOWN_PENDING) { 5805 /* 5806 * We are here likely because the receiver had its rwnd 5807 * closed for a while and we have not been able to 5808 * transmit the locally queued data within the maximum 5809 * retransmission attempts limit. Start the T5 5810 * shutdown guard timer to give the receiver one last 5811 * chance and some additional time to recover before 5812 * aborting. 5813 */ 5814 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE, 5815 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5816 } else { 5817 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5818 SCTP_ERROR(ETIMEDOUT)); 5819 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5820 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5821 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5822 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5823 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5824 return SCTP_DISPOSITION_DELETE_TCB; 5825 } 5826 } 5827 5828 /* E1) For the destination address for which the timer 5829 * expires, adjust its ssthresh with rules defined in Section 5830 * 7.2.3 and set the cwnd <- MTU. 5831 */ 5832 5833 /* E2) For the destination address for which the timer 5834 * expires, set RTO <- RTO * 2 ("back off the timer"). The 5835 * maximum value discussed in rule C7 above (RTO.max) may be 5836 * used to provide an upper bound to this doubling operation. 5837 */ 5838 5839 /* E3) Determine how many of the earliest (i.e., lowest TSN) 5840 * outstanding DATA chunks for the address for which the 5841 * T3-rtx has expired will fit into a single packet, subject 5842 * to the MTU constraint for the path corresponding to the 5843 * destination transport address to which the retransmission 5844 * is being sent (this may be different from the address for 5845 * which the timer expires [see Section 6.4]). Call this 5846 * value K. Bundle and retransmit those K DATA chunks in a 5847 * single packet to the destination endpoint. 5848 * 5849 * Note: Any DATA chunks that were sent to the address for 5850 * which the T3-rtx timer expired but did not fit in one MTU 5851 * (rule E3 above), should be marked for retransmission and 5852 * sent as soon as cwnd allows (normally when a SACK arrives). 5853 */ 5854 5855 /* Do some failure management (Section 8.2). */ 5856 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5857 5858 /* NB: Rules E4 and F1 are implicit in R1. */ 5859 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 5860 5861 return SCTP_DISPOSITION_CONSUME; 5862} 5863 5864/* 5865 * Generate delayed SACK on timeout 5866 * 5867 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 5868 * 5869 * The guidelines on delayed acknowledgement algorithm specified in 5870 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 5871 * acknowledgement SHOULD be generated for at least every second packet 5872 * (not every second DATA chunk) received, and SHOULD be generated 5873 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 5874 * some situations it may be beneficial for an SCTP transmitter to be 5875 * more conservative than the algorithms detailed in this document 5876 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 5877 * the following algorithms allow. 5878 */ 5879enum sctp_disposition sctp_sf_do_6_2_sack(struct net *net, 5880 const struct sctp_endpoint *ep, 5881 const struct sctp_association *asoc, 5882 const union sctp_subtype type, 5883 void *arg, 5884 struct sctp_cmd_seq *commands) 5885{ 5886 SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS); 5887 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 5888 return SCTP_DISPOSITION_CONSUME; 5889} 5890 5891/* 5892 * sctp_sf_t1_init_timer_expire 5893 * 5894 * Section: 4 Note: 2 5895 * Verification Tag: 5896 * Inputs 5897 * (endpoint, asoc) 5898 * 5899 * RFC 2960 Section 4 Notes 5900 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 5901 * and re-start the T1-init timer without changing state. This MUST 5902 * be repeated up to 'Max.Init.Retransmits' times. After that, the 5903 * endpoint MUST abort the initialization process and report the 5904 * error to SCTP user. 5905 * 5906 * Outputs 5907 * (timers, events) 5908 * 5909 */ 5910enum sctp_disposition sctp_sf_t1_init_timer_expire( 5911 struct net *net, 5912 const struct sctp_endpoint *ep, 5913 const struct sctp_association *asoc, 5914 const union sctp_subtype type, 5915 void *arg, 5916 struct sctp_cmd_seq *commands) 5917{ 5918 int attempts = asoc->init_err_counter + 1; 5919 struct sctp_chunk *repl = NULL; 5920 struct sctp_bind_addr *bp; 5921 5922 pr_debug("%s: timer T1 expired (INIT)\n", __func__); 5923 5924 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS); 5925 5926 if (attempts <= asoc->max_init_attempts) { 5927 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 5928 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 5929 if (!repl) 5930 return SCTP_DISPOSITION_NOMEM; 5931 5932 /* Choose transport for INIT. */ 5933 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5934 SCTP_CHUNK(repl)); 5935 5936 /* Issue a sideeffect to do the needed accounting. */ 5937 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 5938 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5939 5940 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5941 } else { 5942 pr_debug("%s: giving up on INIT, attempts:%d " 5943 "max_init_attempts:%d\n", __func__, attempts, 5944 asoc->max_init_attempts); 5945 5946 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5947 SCTP_ERROR(ETIMEDOUT)); 5948 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5949 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5950 return SCTP_DISPOSITION_DELETE_TCB; 5951 } 5952 5953 return SCTP_DISPOSITION_CONSUME; 5954} 5955 5956/* 5957 * sctp_sf_t1_cookie_timer_expire 5958 * 5959 * Section: 4 Note: 2 5960 * Verification Tag: 5961 * Inputs 5962 * (endpoint, asoc) 5963 * 5964 * RFC 2960 Section 4 Notes 5965 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 5966 * COOKIE ECHO and re-start the T1-cookie timer without changing 5967 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 5968 * After that, the endpoint MUST abort the initialization process and 5969 * report the error to SCTP user. 5970 * 5971 * Outputs 5972 * (timers, events) 5973 * 5974 */ 5975enum sctp_disposition sctp_sf_t1_cookie_timer_expire( 5976 struct net *net, 5977 const struct sctp_endpoint *ep, 5978 const struct sctp_association *asoc, 5979 const union sctp_subtype type, 5980 void *arg, 5981 struct sctp_cmd_seq *commands) 5982{ 5983 int attempts = asoc->init_err_counter + 1; 5984 struct sctp_chunk *repl = NULL; 5985 5986 pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__); 5987 5988 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS); 5989 5990 if (attempts <= asoc->max_init_attempts) { 5991 repl = sctp_make_cookie_echo(asoc, NULL); 5992 if (!repl) 5993 return SCTP_DISPOSITION_NOMEM; 5994 5995 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5996 SCTP_CHUNK(repl)); 5997 /* Issue a sideeffect to do the needed accounting. */ 5998 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 5999 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 6000 6001 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 6002 } else { 6003 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6004 SCTP_ERROR(ETIMEDOUT)); 6005 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 6006 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6007 return SCTP_DISPOSITION_DELETE_TCB; 6008 } 6009 6010 return SCTP_DISPOSITION_CONSUME; 6011} 6012 6013/* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 6014 * with the updated last sequential TSN received from its peer. 6015 * 6016 * An endpoint should limit the number of retransmission of the 6017 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 6018 * If this threshold is exceeded the endpoint should destroy the TCB and 6019 * MUST report the peer endpoint unreachable to the upper layer (and 6020 * thus the association enters the CLOSED state). The reception of any 6021 * packet from its peer (i.e. as the peer sends all of its queued DATA 6022 * chunks) should clear the endpoint's retransmission count and restart 6023 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 6024 * all of its queued DATA chunks that have not yet been sent. 6025 */ 6026enum sctp_disposition sctp_sf_t2_timer_expire( 6027 struct net *net, 6028 const struct sctp_endpoint *ep, 6029 const struct sctp_association *asoc, 6030 const union sctp_subtype type, 6031 void *arg, 6032 struct sctp_cmd_seq *commands) 6033{ 6034 struct sctp_chunk *reply = NULL; 6035 6036 pr_debug("%s: timer T2 expired\n", __func__); 6037 6038 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS); 6039 6040 ((struct sctp_association *)asoc)->shutdown_retries++; 6041 6042 if (asoc->overall_error_count >= asoc->max_retrans) { 6043 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6044 SCTP_ERROR(ETIMEDOUT)); 6045 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 6046 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6047 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6048 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6049 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6050 return SCTP_DISPOSITION_DELETE_TCB; 6051 } 6052 6053 switch (asoc->state) { 6054 case SCTP_STATE_SHUTDOWN_SENT: 6055 reply = sctp_make_shutdown(asoc, NULL); 6056 break; 6057 6058 case SCTP_STATE_SHUTDOWN_ACK_SENT: 6059 reply = sctp_make_shutdown_ack(asoc, NULL); 6060 break; 6061 6062 default: 6063 BUG(); 6064 break; 6065 } 6066 6067 if (!reply) 6068 goto nomem; 6069 6070 /* Do some failure management (Section 8.2). 6071 * If we remove the transport an SHUTDOWN was last sent to, don't 6072 * do failure management. 6073 */ 6074 if (asoc->shutdown_last_sent_to) 6075 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 6076 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 6077 6078 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 6079 * the T2-shutdown timer. 6080 */ 6081 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 6082 6083 /* Restart the T2-shutdown timer. */ 6084 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 6085 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 6086 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 6087 return SCTP_DISPOSITION_CONSUME; 6088 6089nomem: 6090 return SCTP_DISPOSITION_NOMEM; 6091} 6092 6093/* 6094 * ADDIP Section 4.1 ASCONF Chunk Procedures 6095 * If the T4 RTO timer expires the endpoint should do B1 to B5 6096 */ 6097enum sctp_disposition sctp_sf_t4_timer_expire( 6098 struct net *net, 6099 const struct sctp_endpoint *ep, 6100 const struct sctp_association *asoc, 6101 const union sctp_subtype type, 6102 void *arg, 6103 struct sctp_cmd_seq *commands) 6104{ 6105 struct sctp_chunk *chunk = asoc->addip_last_asconf; 6106 struct sctp_transport *transport = chunk->transport; 6107 6108 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS); 6109 6110 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 6111 * detection on the appropriate destination address as defined in 6112 * RFC2960 [5] section 8.1 and 8.2. 6113 */ 6114 if (transport) 6115 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 6116 SCTP_TRANSPORT(transport)); 6117 6118 /* Reconfig T4 timer and transport. */ 6119 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 6120 6121 /* ADDIP 4.1 B2) Increment the association error counters and perform 6122 * endpoint failure detection on the association as defined in 6123 * RFC2960 [5] section 8.1 and 8.2. 6124 * association error counter is incremented in SCTP_CMD_STRIKE. 6125 */ 6126 if (asoc->overall_error_count >= asoc->max_retrans) { 6127 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 6128 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 6129 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6130 SCTP_ERROR(ETIMEDOUT)); 6131 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6132 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6133 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6134 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6135 return SCTP_DISPOSITION_ABORT; 6136 } 6137 6138 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 6139 * the ASCONF chunk was sent by doubling the RTO timer value. 6140 * This is done in SCTP_CMD_STRIKE. 6141 */ 6142 6143 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 6144 * choose an alternate destination address (please refer to RFC2960 6145 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 6146 * chunk, it MUST be the same (including its serial number) as the last 6147 * ASCONF sent. 6148 */ 6149 sctp_chunk_hold(asoc->addip_last_asconf); 6150 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6151 SCTP_CHUNK(asoc->addip_last_asconf)); 6152 6153 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 6154 * destination is selected, then the RTO used will be that of the new 6155 * destination address. 6156 */ 6157 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 6158 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 6159 6160 return SCTP_DISPOSITION_CONSUME; 6161} 6162 6163/* sctpimpguide-05 Section 2.12.2 6164 * The sender of the SHUTDOWN MAY also start an overall guard timer 6165 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 6166 * At the expiration of this timer the sender SHOULD abort the association 6167 * by sending an ABORT chunk. 6168 */ 6169enum sctp_disposition sctp_sf_t5_timer_expire( 6170 struct net *net, 6171 const struct sctp_endpoint *ep, 6172 const struct sctp_association *asoc, 6173 const union sctp_subtype type, 6174 void *arg, 6175 struct sctp_cmd_seq *commands) 6176{ 6177 struct sctp_chunk *reply = NULL; 6178 6179 pr_debug("%s: timer T5 expired\n", __func__); 6180 6181 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS); 6182 6183 reply = sctp_make_abort(asoc, NULL, 0); 6184 if (!reply) 6185 goto nomem; 6186 6187 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 6188 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6189 SCTP_ERROR(ETIMEDOUT)); 6190 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6191 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6192 6193 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6194 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6195 6196 return SCTP_DISPOSITION_DELETE_TCB; 6197nomem: 6198 return SCTP_DISPOSITION_NOMEM; 6199} 6200 6201/* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 6202 * the association is automatically closed by starting the shutdown process. 6203 * The work that needs to be done is same as when SHUTDOWN is initiated by 6204 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 6205 */ 6206enum sctp_disposition sctp_sf_autoclose_timer_expire( 6207 struct net *net, 6208 const struct sctp_endpoint *ep, 6209 const struct sctp_association *asoc, 6210 const union sctp_subtype type, 6211 void *arg, 6212 struct sctp_cmd_seq *commands) 6213{ 6214 enum sctp_disposition disposition; 6215 6216 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS); 6217 6218 /* From 9.2 Shutdown of an Association 6219 * Upon receipt of the SHUTDOWN primitive from its upper 6220 * layer, the endpoint enters SHUTDOWN-PENDING state and 6221 * remains there until all outstanding data has been 6222 * acknowledged by its peer. The endpoint accepts no new data 6223 * from its upper layer, but retransmits data to the far end 6224 * if necessary to fill gaps. 6225 */ 6226 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 6227 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 6228 6229 disposition = SCTP_DISPOSITION_CONSUME; 6230 if (sctp_outq_is_empty(&asoc->outqueue)) { 6231 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 6232 NULL, commands); 6233 } 6234 6235 return disposition; 6236} 6237 6238/***************************************************************************** 6239 * These are sa state functions which could apply to all types of events. 6240 ****************************************************************************/ 6241 6242/* 6243 * This table entry is not implemented. 6244 * 6245 * Inputs 6246 * (endpoint, asoc, chunk) 6247 * 6248 * The return value is the disposition of the chunk. 6249 */ 6250enum sctp_disposition sctp_sf_not_impl(struct net *net, 6251 const struct sctp_endpoint *ep, 6252 const struct sctp_association *asoc, 6253 const union sctp_subtype type, 6254 void *arg, struct sctp_cmd_seq *commands) 6255{ 6256 return SCTP_DISPOSITION_NOT_IMPL; 6257} 6258 6259/* 6260 * This table entry represents a bug. 6261 * 6262 * Inputs 6263 * (endpoint, asoc, chunk) 6264 * 6265 * The return value is the disposition of the chunk. 6266 */ 6267enum sctp_disposition sctp_sf_bug(struct net *net, 6268 const struct sctp_endpoint *ep, 6269 const struct sctp_association *asoc, 6270 const union sctp_subtype type, 6271 void *arg, struct sctp_cmd_seq *commands) 6272{ 6273 return SCTP_DISPOSITION_BUG; 6274} 6275 6276/* 6277 * This table entry represents the firing of a timer in the wrong state. 6278 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 6279 * when the association is in the wrong state. This event should 6280 * be ignored, so as to prevent any rearming of the timer. 6281 * 6282 * Inputs 6283 * (endpoint, asoc, chunk) 6284 * 6285 * The return value is the disposition of the chunk. 6286 */ 6287enum sctp_disposition sctp_sf_timer_ignore(struct net *net, 6288 const struct sctp_endpoint *ep, 6289 const struct sctp_association *asoc, 6290 const union sctp_subtype type, 6291 void *arg, 6292 struct sctp_cmd_seq *commands) 6293{ 6294 pr_debug("%s: timer %d ignored\n", __func__, type.chunk); 6295 6296 return SCTP_DISPOSITION_CONSUME; 6297} 6298 6299/******************************************************************** 6300 * 2nd Level Abstractions 6301 ********************************************************************/ 6302 6303/* Pull the SACK chunk based on the SACK header. */ 6304static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 6305{ 6306 struct sctp_sackhdr *sack; 6307 __u16 num_dup_tsns; 6308 unsigned int len; 6309 __u16 num_blocks; 6310 6311 /* Protect ourselves from reading too far into 6312 * the skb from a bogus sender. 6313 */ 6314 sack = (struct sctp_sackhdr *) chunk->skb->data; 6315 6316 num_blocks = ntohs(sack->num_gap_ack_blocks); 6317 num_dup_tsns = ntohs(sack->num_dup_tsns); 6318 len = sizeof(struct sctp_sackhdr); 6319 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 6320 if (len > chunk->skb->len) 6321 return NULL; 6322 6323 skb_pull(chunk->skb, len); 6324 6325 return sack; 6326} 6327 6328/* Create an ABORT packet to be sent as a response, with the specified 6329 * error causes. 6330 */ 6331static struct sctp_packet *sctp_abort_pkt_new( 6332 struct net *net, 6333 const struct sctp_endpoint *ep, 6334 const struct sctp_association *asoc, 6335 struct sctp_chunk *chunk, 6336 const void *payload, size_t paylen) 6337{ 6338 struct sctp_packet *packet; 6339 struct sctp_chunk *abort; 6340 6341 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6342 6343 if (packet) { 6344 /* Make an ABORT. 6345 * The T bit will be set if the asoc is NULL. 6346 */ 6347 abort = sctp_make_abort(asoc, chunk, paylen); 6348 if (!abort) { 6349 sctp_ootb_pkt_free(packet); 6350 return NULL; 6351 } 6352 6353 /* Reflect vtag if T-Bit is set */ 6354 if (sctp_test_T_bit(abort)) 6355 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 6356 6357 /* Add specified error causes, i.e., payload, to the 6358 * end of the chunk. 6359 */ 6360 sctp_addto_chunk(abort, paylen, payload); 6361 6362 /* Set the skb to the belonging sock for accounting. */ 6363 abort->skb->sk = ep->base.sk; 6364 6365 sctp_packet_append_chunk(packet, abort); 6366 6367 } 6368 6369 return packet; 6370} 6371 6372/* Allocate a packet for responding in the OOTB conditions. */ 6373static struct sctp_packet *sctp_ootb_pkt_new( 6374 struct net *net, 6375 const struct sctp_association *asoc, 6376 const struct sctp_chunk *chunk) 6377{ 6378 struct sctp_transport *transport; 6379 struct sctp_packet *packet; 6380 __u16 sport, dport; 6381 __u32 vtag; 6382 6383 /* Get the source and destination port from the inbound packet. */ 6384 sport = ntohs(chunk->sctp_hdr->dest); 6385 dport = ntohs(chunk->sctp_hdr->source); 6386 6387 /* The V-tag is going to be the same as the inbound packet if no 6388 * association exists, otherwise, use the peer's vtag. 6389 */ 6390 if (asoc) { 6391 /* Special case the INIT-ACK as there is no peer's vtag 6392 * yet. 6393 */ 6394 switch (chunk->chunk_hdr->type) { 6395 case SCTP_CID_INIT: 6396 case SCTP_CID_INIT_ACK: 6397 { 6398 struct sctp_initack_chunk *initack; 6399 6400 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr; 6401 vtag = ntohl(initack->init_hdr.init_tag); 6402 break; 6403 } 6404 default: 6405 vtag = asoc->peer.i.init_tag; 6406 break; 6407 } 6408 } else { 6409 /* Special case the INIT and stale COOKIE_ECHO as there is no 6410 * vtag yet. 6411 */ 6412 switch (chunk->chunk_hdr->type) { 6413 case SCTP_CID_INIT: 6414 { 6415 struct sctp_init_chunk *init; 6416 6417 init = (struct sctp_init_chunk *)chunk->chunk_hdr; 6418 vtag = ntohl(init->init_hdr.init_tag); 6419 break; 6420 } 6421 default: 6422 vtag = ntohl(chunk->sctp_hdr->vtag); 6423 break; 6424 } 6425 } 6426 6427 /* Make a transport for the bucket, Eliza... */ 6428 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC); 6429 if (!transport) 6430 goto nomem; 6431 6432 transport->encap_port = SCTP_INPUT_CB(chunk->skb)->encap_port; 6433 6434 /* Cache a route for the transport with the chunk's destination as 6435 * the source address. 6436 */ 6437 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 6438 sctp_sk(net->sctp.ctl_sock)); 6439 6440 packet = &transport->packet; 6441 sctp_packet_init(packet, transport, sport, dport); 6442 sctp_packet_config(packet, vtag, 0); 6443 6444 return packet; 6445 6446nomem: 6447 return NULL; 6448} 6449 6450/* Free the packet allocated earlier for responding in the OOTB condition. */ 6451void sctp_ootb_pkt_free(struct sctp_packet *packet) 6452{ 6453 sctp_transport_free(packet->transport); 6454} 6455 6456/* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 6457static void sctp_send_stale_cookie_err(struct net *net, 6458 const struct sctp_endpoint *ep, 6459 const struct sctp_association *asoc, 6460 const struct sctp_chunk *chunk, 6461 struct sctp_cmd_seq *commands, 6462 struct sctp_chunk *err_chunk) 6463{ 6464 struct sctp_packet *packet; 6465 6466 if (err_chunk) { 6467 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6468 if (packet) { 6469 struct sctp_signed_cookie *cookie; 6470 6471 /* Override the OOTB vtag from the cookie. */ 6472 cookie = chunk->subh.cookie_hdr; 6473 packet->vtag = cookie->c.peer_vtag; 6474 6475 /* Set the skb to the belonging sock for accounting. */ 6476 err_chunk->skb->sk = ep->base.sk; 6477 sctp_packet_append_chunk(packet, err_chunk); 6478 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 6479 SCTP_PACKET(packet)); 6480 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 6481 } else 6482 sctp_chunk_free (err_chunk); 6483 } 6484} 6485 6486 6487/* Process a data chunk */ 6488static int sctp_eat_data(const struct sctp_association *asoc, 6489 struct sctp_chunk *chunk, 6490 struct sctp_cmd_seq *commands) 6491{ 6492 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; 6493 struct sock *sk = asoc->base.sk; 6494 struct net *net = sock_net(sk); 6495 struct sctp_datahdr *data_hdr; 6496 struct sctp_chunk *err; 6497 enum sctp_verb deliver; 6498 size_t datalen; 6499 __u32 tsn; 6500 int tmp; 6501 6502 data_hdr = (struct sctp_datahdr *)chunk->skb->data; 6503 chunk->subh.data_hdr = data_hdr; 6504 skb_pull(chunk->skb, sctp_datahdr_len(&asoc->stream)); 6505 6506 tsn = ntohl(data_hdr->tsn); 6507 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 6508 6509 /* ASSERT: Now skb->data is really the user data. */ 6510 6511 /* Process ECN based congestion. 6512 * 6513 * Since the chunk structure is reused for all chunks within 6514 * a packet, we use ecn_ce_done to track if we've already 6515 * done CE processing for this packet. 6516 * 6517 * We need to do ECN processing even if we plan to discard the 6518 * chunk later. 6519 */ 6520 6521 if (asoc->peer.ecn_capable && !chunk->ecn_ce_done) { 6522 struct sctp_af *af = SCTP_INPUT_CB(chunk->skb)->af; 6523 chunk->ecn_ce_done = 1; 6524 6525 if (af->is_ce(sctp_gso_headskb(chunk->skb))) { 6526 /* Do real work as side effect. */ 6527 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 6528 SCTP_U32(tsn)); 6529 } 6530 } 6531 6532 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 6533 if (tmp < 0) { 6534 /* The TSN is too high--silently discard the chunk and 6535 * count on it getting retransmitted later. 6536 */ 6537 if (chunk->asoc) 6538 chunk->asoc->stats.outofseqtsns++; 6539 return SCTP_IERROR_HIGH_TSN; 6540 } else if (tmp > 0) { 6541 /* This is a duplicate. Record it. */ 6542 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 6543 return SCTP_IERROR_DUP_TSN; 6544 } 6545 6546 /* This is a new TSN. */ 6547 6548 /* Discard if there is no room in the receive window. 6549 * Actually, allow a little bit of overflow (up to a MTU). 6550 */ 6551 datalen = ntohs(chunk->chunk_hdr->length); 6552 datalen -= sctp_datachk_len(&asoc->stream); 6553 6554 deliver = SCTP_CMD_CHUNK_ULP; 6555 6556 /* Think about partial delivery. */ 6557 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 6558 6559 /* Even if we don't accept this chunk there is 6560 * memory pressure. 6561 */ 6562 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 6563 } 6564 6565 /* Spill over rwnd a little bit. Note: While allowed, this spill over 6566 * seems a bit troublesome in that frag_point varies based on 6567 * PMTU. In cases, such as loopback, this might be a rather 6568 * large spill over. 6569 */ 6570 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over || 6571 (datalen > asoc->rwnd + asoc->frag_point))) { 6572 6573 /* If this is the next TSN, consider reneging to make 6574 * room. Note: Playing nice with a confused sender. A 6575 * malicious sender can still eat up all our buffer 6576 * space and in the future we may want to detect and 6577 * do more drastic reneging. 6578 */ 6579 if (sctp_tsnmap_has_gap(map) && 6580 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6581 pr_debug("%s: reneging for tsn:%u\n", __func__, tsn); 6582 deliver = SCTP_CMD_RENEGE; 6583 } else { 6584 pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n", 6585 __func__, tsn, datalen, asoc->rwnd); 6586 6587 return SCTP_IERROR_IGNORE_TSN; 6588 } 6589 } 6590 6591 /* 6592 * Also try to renege to limit our memory usage in the event that 6593 * we are under memory pressure 6594 * If we can't renege, don't worry about it, the sk_rmem_schedule 6595 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our 6596 * memory usage too much 6597 */ 6598 if (sk_under_memory_pressure(sk)) { 6599 if (sctp_tsnmap_has_gap(map) && 6600 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6601 pr_debug("%s: under pressure, reneging for tsn:%u\n", 6602 __func__, tsn); 6603 deliver = SCTP_CMD_RENEGE; 6604 } 6605 } 6606 6607 /* 6608 * Section 3.3.10.9 No User Data (9) 6609 * 6610 * Cause of error 6611 * --------------- 6612 * No User Data: This error cause is returned to the originator of a 6613 * DATA chunk if a received DATA chunk has no user data. 6614 */ 6615 if (unlikely(0 == datalen)) { 6616 err = sctp_make_abort_no_data(asoc, chunk, tsn); 6617 if (err) { 6618 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6619 SCTP_CHUNK(err)); 6620 } 6621 /* We are going to ABORT, so we might as well stop 6622 * processing the rest of the chunks in the packet. 6623 */ 6624 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 6625 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6626 SCTP_ERROR(ECONNABORTED)); 6627 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6628 SCTP_PERR(SCTP_ERROR_NO_DATA)); 6629 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6630 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6631 return SCTP_IERROR_NO_DATA; 6632 } 6633 6634 chunk->data_accepted = 1; 6635 6636 /* Note: Some chunks may get overcounted (if we drop) or overcounted 6637 * if we renege and the chunk arrives again. 6638 */ 6639 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) { 6640 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS); 6641 if (chunk->asoc) 6642 chunk->asoc->stats.iuodchunks++; 6643 } else { 6644 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS); 6645 if (chunk->asoc) 6646 chunk->asoc->stats.iodchunks++; 6647 } 6648 6649 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 6650 * 6651 * If an endpoint receive a DATA chunk with an invalid stream 6652 * identifier, it shall acknowledge the reception of the DATA chunk 6653 * following the normal procedure, immediately send an ERROR chunk 6654 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 6655 * and discard the DATA chunk. 6656 */ 6657 if (ntohs(data_hdr->stream) >= asoc->stream.incnt) { 6658 /* Mark tsn as received even though we drop it */ 6659 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 6660 6661 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 6662 &data_hdr->stream, 6663 sizeof(data_hdr->stream), 6664 sizeof(u16)); 6665 if (err) 6666 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6667 SCTP_CHUNK(err)); 6668 return SCTP_IERROR_BAD_STREAM; 6669 } 6670 6671 /* Check to see if the SSN is possible for this TSN. 6672 * The biggest gap we can record is 4K wide. Since SSNs wrap 6673 * at an unsigned short, there is no way that an SSN can 6674 * wrap and for a valid TSN. We can simply check if the current 6675 * SSN is smaller then the next expected one. If it is, it wrapped 6676 * and is invalid. 6677 */ 6678 if (!asoc->stream.si->validate_data(chunk)) 6679 return SCTP_IERROR_PROTO_VIOLATION; 6680 6681 /* Send the data up to the user. Note: Schedule the 6682 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 6683 * chunk needs the updated rwnd. 6684 */ 6685 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 6686 6687 return SCTP_IERROR_NO_ERROR; 6688}
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