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