1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* SCTP kernel implementation 3 * (C) Copyright IBM Corp. 2001, 2004 4 * Copyright (c) 1999-2000 Cisco, Inc. 5 * Copyright (c) 1999-2001 Motorola, Inc. 6 * Copyright (c) 2001-2002 Intel Corp. 7 * Copyright (c) 2002 Nokia Corp. 8 * 9 * This is part of the SCTP Linux Kernel Implementation. 10 * 11 * These are the state functions for the state machine. 12 * 13 * Please send any bug reports or fixes you make to the 14 * email address(es): 15 * lksctp developers <linux-sctp@vger.kernel.org> 16 * 17 * Written or modified by: 18 * La Monte H.P. Yarroll <piggy@acm.org> 19 * Karl Knutson <karl@athena.chicago.il.us> 20 * Mathew Kotowsky <kotowsky@sctp.org> 21 * Sridhar Samudrala <samudrala@us.ibm.com> 22 * Jon Grimm <jgrimm@us.ibm.com> 23 * Hui Huang <hui.huang@nokia.com> 24 * Dajiang Zhang <dajiang.zhang@nokia.com> 25 * Daisy Chang <daisyc@us.ibm.com> 26 * Ardelle Fan <ardelle.fan@intel.com> 27 * Ryan Layer <rmlayer@us.ibm.com> 28 * Kevin Gao <kevin.gao@intel.com> 29 */ 30 31 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 32 33 #include <crypto/utils.h> 34 #include <linux/types.h> 35 #include <linux/kernel.h> 36 #include <linux/ip.h> 37 #include <linux/ipv6.h> 38 #include <linux/net.h> 39 #include <linux/inet.h> 40 #include <linux/slab.h> 41 #include <net/sock.h> 42 #include <net/proto_memory.h> 43 #include <net/inet_ecn.h> 44 #include <linux/skbuff.h> 45 #include <net/sctp/sctp.h> 46 #include <net/sctp/sm.h> 47 #include <net/sctp/structs.h> 48 49 #define CREATE_TRACE_POINTS 50 #include <trace/events/sctp.h> 51 52 static struct sctp_packet *sctp_abort_pkt_new( 53 struct net *net, 54 const struct sctp_endpoint *ep, 55 const struct sctp_association *asoc, 56 struct sctp_chunk *chunk, 57 const void *payload, size_t paylen); 58 static int sctp_eat_data(const struct sctp_association *asoc, 59 struct sctp_chunk *chunk, 60 struct sctp_cmd_seq *commands); 61 static struct sctp_packet *sctp_ootb_pkt_new( 62 struct net *net, 63 const struct sctp_association *asoc, 64 const struct sctp_chunk *chunk); 65 static void sctp_send_stale_cookie_err(struct net *net, 66 const struct sctp_endpoint *ep, 67 const struct sctp_association *asoc, 68 const struct sctp_chunk *chunk, 69 struct sctp_cmd_seq *commands, 70 struct sctp_chunk *err_chunk); 71 static enum sctp_disposition sctp_sf_do_5_2_6_stale( 72 struct net *net, 73 const struct sctp_endpoint *ep, 74 const struct sctp_association *asoc, 75 const union sctp_subtype type, 76 void *arg, 77 struct sctp_cmd_seq *commands); 78 static enum sctp_disposition sctp_sf_shut_8_4_5( 79 struct net *net, 80 const struct sctp_endpoint *ep, 81 const struct sctp_association *asoc, 82 const union sctp_subtype type, 83 void *arg, 84 struct sctp_cmd_seq *commands); 85 static enum sctp_disposition sctp_sf_tabort_8_4_8( 86 struct net *net, 87 const struct sctp_endpoint *ep, 88 const struct sctp_association *asoc, 89 const union sctp_subtype type, 90 void *arg, 91 struct sctp_cmd_seq *commands); 92 static enum sctp_disposition sctp_sf_new_encap_port( 93 struct net *net, 94 const struct sctp_endpoint *ep, 95 const struct sctp_association *asoc, 96 const union sctp_subtype type, 97 void *arg, 98 struct sctp_cmd_seq *commands); 99 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk); 100 101 static enum sctp_disposition sctp_stop_t1_and_abort( 102 struct net *net, 103 struct sctp_cmd_seq *commands, 104 __be16 error, int sk_err, 105 const struct sctp_association *asoc, 106 struct sctp_transport *transport); 107 108 static enum sctp_disposition sctp_sf_abort_violation( 109 struct net *net, 110 const struct sctp_endpoint *ep, 111 const struct sctp_association *asoc, 112 void *arg, 113 struct sctp_cmd_seq *commands, 114 const __u8 *payload, 115 const size_t paylen); 116 117 static enum sctp_disposition sctp_sf_violation_chunklen( 118 struct net *net, 119 const struct sctp_endpoint *ep, 120 const struct sctp_association *asoc, 121 const union sctp_subtype type, 122 void *arg, 123 struct sctp_cmd_seq *commands); 124 125 static enum sctp_disposition sctp_sf_violation_paramlen( 126 struct net *net, 127 const struct sctp_endpoint *ep, 128 const struct sctp_association *asoc, 129 const union sctp_subtype type, 130 void *arg, void *ext, 131 struct sctp_cmd_seq *commands); 132 133 static enum sctp_disposition sctp_sf_violation_ctsn( 134 struct net *net, 135 const struct sctp_endpoint *ep, 136 const struct sctp_association *asoc, 137 const union sctp_subtype type, 138 void *arg, 139 struct sctp_cmd_seq *commands); 140 141 static enum sctp_disposition sctp_sf_violation_chunk( 142 struct net *net, 143 const struct sctp_endpoint *ep, 144 const struct sctp_association *asoc, 145 const union sctp_subtype type, 146 void *arg, 147 struct sctp_cmd_seq *commands); 148 149 static enum sctp_ierror sctp_sf_authenticate( 150 const struct sctp_association *asoc, 151 struct sctp_chunk *chunk); 152 153 static enum sctp_disposition __sctp_sf_do_9_1_abort( 154 struct net *net, 155 const struct sctp_endpoint *ep, 156 const struct sctp_association *asoc, 157 const union sctp_subtype type, 158 void *arg, 159 struct sctp_cmd_seq *commands); 160 161 static enum sctp_disposition 162 __sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep, 163 const struct sctp_association *asoc, 164 const union sctp_subtype type, void *arg, 165 struct sctp_cmd_seq *commands); 166 167 /* Small helper function that checks if the chunk length 168 * is of the appropriate length. The 'required_length' argument 169 * is set to be the size of a specific chunk we are testing. 170 * Return Values: true = Valid length 171 * false = Invalid length 172 * 173 */ 174 static inline bool sctp_chunk_length_valid(struct sctp_chunk *chunk, 175 __u16 required_length) 176 { 177 __u16 chunk_length = ntohs(chunk->chunk_hdr->length); 178 179 /* Previously already marked? */ 180 if (unlikely(chunk->pdiscard)) 181 return false; 182 if (unlikely(chunk_length < required_length)) 183 return false; 184 185 return true; 186 } 187 188 /* Check for format error in an ABORT chunk */ 189 static inline bool sctp_err_chunk_valid(struct sctp_chunk *chunk) 190 { 191 struct sctp_errhdr *err; 192 193 sctp_walk_errors(err, chunk->chunk_hdr); 194 195 return (void *)err == (void *)chunk->chunk_end; 196 } 197 198 /********************************************************** 199 * These are the state functions for handling chunk events. 200 **********************************************************/ 201 202 /* 203 * Process the final SHUTDOWN COMPLETE. 204 * 205 * Section: 4 (C) (diagram), 9.2 206 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify 207 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be 208 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint 209 * should stop the T2-shutdown timer and remove all knowledge of the 210 * association (and thus the association enters the CLOSED state). 211 * 212 * Verification Tag: 8.5.1(C), sctpimpguide 2.41. 213 * C) Rules for packet carrying SHUTDOWN COMPLETE: 214 * ... 215 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet 216 * if the Verification Tag field of the packet matches its own tag and 217 * the T bit is not set 218 * OR 219 * it is set to its peer's tag and the T bit is set in the Chunk 220 * Flags. 221 * Otherwise, the receiver MUST silently discard the packet 222 * and take no further action. An endpoint MUST ignore the 223 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state. 224 * 225 * Inputs 226 * (endpoint, asoc, chunk) 227 * 228 * Outputs 229 * (asoc, reply_msg, msg_up, timers, counters) 230 * 231 * The return value is the disposition of the chunk. 232 */ 233 enum sctp_disposition sctp_sf_do_4_C(struct net *net, 234 const struct sctp_endpoint *ep, 235 const struct sctp_association *asoc, 236 const union sctp_subtype type, 237 void *arg, struct sctp_cmd_seq *commands) 238 { 239 struct sctp_chunk *chunk = arg; 240 struct sctp_ulpevent *ev; 241 242 if (!sctp_vtag_verify_either(chunk, asoc)) 243 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 244 245 /* RFC 2960 6.10 Bundling 246 * 247 * An endpoint MUST NOT bundle INIT, INIT ACK or 248 * SHUTDOWN COMPLETE with any other chunks. 249 */ 250 if (!chunk->singleton) 251 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 252 253 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */ 254 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 255 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 256 commands); 257 258 /* RFC 2960 10.2 SCTP-to-ULP 259 * 260 * H) SHUTDOWN COMPLETE notification 261 * 262 * When SCTP completes the shutdown procedures (section 9.2) this 263 * notification is passed to the upper layer. 264 */ 265 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 266 0, 0, 0, NULL, GFP_ATOMIC); 267 if (ev) 268 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 269 SCTP_ULPEVENT(ev)); 270 271 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint 272 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is 273 * not the chunk should be discarded. If the endpoint is in 274 * the SHUTDOWN-ACK-SENT state the endpoint should stop the 275 * T2-shutdown timer and remove all knowledge of the 276 * association (and thus the association enters the CLOSED 277 * state). 278 */ 279 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 280 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 281 282 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 283 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 284 285 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 286 SCTP_STATE(SCTP_STATE_CLOSED)); 287 288 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 289 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 290 291 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 292 293 return SCTP_DISPOSITION_DELETE_TCB; 294 } 295 296 /* 297 * Respond to a normal INIT chunk. 298 * We are the side that is being asked for an association. 299 * 300 * Section: 5.1 Normal Establishment of an Association, B 301 * B) "Z" shall respond immediately with an INIT ACK chunk. The 302 * destination IP address of the INIT ACK MUST be set to the source 303 * IP address of the INIT to which this INIT ACK is responding. In 304 * the response, besides filling in other parameters, "Z" must set the 305 * Verification Tag field to Tag_A, and also provide its own 306 * Verification Tag (Tag_Z) in the Initiate Tag field. 307 * 308 * Verification Tag: Must be 0. 309 * 310 * Inputs 311 * (endpoint, asoc, chunk) 312 * 313 * Outputs 314 * (asoc, reply_msg, msg_up, timers, counters) 315 * 316 * The return value is the disposition of the chunk. 317 */ 318 enum sctp_disposition sctp_sf_do_5_1B_init(struct net *net, 319 const struct sctp_endpoint *ep, 320 const struct sctp_association *asoc, 321 const union sctp_subtype type, 322 void *arg, 323 struct sctp_cmd_seq *commands) 324 { 325 struct sctp_chunk *chunk = arg, *repl, *err_chunk; 326 struct sctp_unrecognized_param *unk_param; 327 struct sctp_association *new_asoc; 328 struct sctp_packet *packet; 329 int len; 330 331 /* 6.10 Bundling 332 * An endpoint MUST NOT bundle INIT, INIT ACK or 333 * SHUTDOWN COMPLETE with any other chunks. 334 * 335 * IG Section 2.11.2 336 * Furthermore, we require that the receiver of an INIT chunk MUST 337 * enforce these rules by silently discarding an arriving packet 338 * with an INIT chunk that is bundled with other chunks. 339 */ 340 if (!chunk->singleton) 341 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 342 343 /* Make sure that the INIT chunk has a valid length. 344 * Normally, this would cause an ABORT with a Protocol Violation 345 * error, but since we don't have an association, we'll 346 * just discard the packet. 347 */ 348 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk))) 349 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 350 351 /* If the packet is an OOTB packet which is temporarily on the 352 * control endpoint, respond with an ABORT. 353 */ 354 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 355 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 356 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 357 } 358 359 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 360 * Tag. 361 */ 362 if (chunk->sctp_hdr->vtag != 0) 363 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 364 365 /* If the INIT is coming toward a closing socket, we'll send back 366 * and ABORT. Essentially, this catches the race of INIT being 367 * backloged to the socket at the same time as the user issues close(). 368 * Since the socket and all its associations are going away, we 369 * can treat this OOTB 370 */ 371 if (sctp_sstate(ep->base.sk, CLOSING)) 372 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 373 374 /* Verify the INIT chunk before processing it. */ 375 err_chunk = NULL; 376 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 377 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 378 &err_chunk)) { 379 /* This chunk contains fatal error. It is to be discarded. 380 * Send an ABORT, with causes if there is any. 381 */ 382 if (err_chunk) { 383 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 384 (__u8 *)(err_chunk->chunk_hdr) + 385 sizeof(struct sctp_chunkhdr), 386 ntohs(err_chunk->chunk_hdr->length) - 387 sizeof(struct sctp_chunkhdr)); 388 389 sctp_chunk_free(err_chunk); 390 391 if (packet) { 392 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 393 SCTP_PACKET(packet)); 394 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 395 return SCTP_DISPOSITION_CONSUME; 396 } else { 397 return SCTP_DISPOSITION_NOMEM; 398 } 399 } else { 400 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 401 commands); 402 } 403 } 404 405 /* Grab the INIT header. */ 406 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 407 408 /* Tag the variable length parameters. */ 409 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 410 411 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 412 if (!new_asoc) 413 goto nomem; 414 415 /* Update socket peer label if first association. */ 416 if (security_sctp_assoc_request(new_asoc, chunk->skb)) { 417 sctp_association_free(new_asoc); 418 if (err_chunk) 419 sctp_chunk_free(err_chunk); 420 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 421 } 422 423 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 424 sctp_scope(sctp_source(chunk)), 425 GFP_ATOMIC) < 0) 426 goto nomem_init; 427 428 /* The call, sctp_process_init(), can fail on memory allocation. */ 429 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 430 (struct sctp_init_chunk *)chunk->chunk_hdr, 431 GFP_ATOMIC)) 432 goto nomem_init; 433 434 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 435 436 /* If there are errors need to be reported for unknown parameters, 437 * make sure to reserve enough room in the INIT ACK for them. 438 */ 439 len = 0; 440 if (err_chunk) 441 len = ntohs(err_chunk->chunk_hdr->length) - 442 sizeof(struct sctp_chunkhdr); 443 444 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 445 if (!repl) 446 goto nomem_init; 447 448 /* If there are errors need to be reported for unknown parameters, 449 * include them in the outgoing INIT ACK as "Unrecognized parameter" 450 * parameter. 451 */ 452 if (err_chunk) { 453 /* Get the "Unrecognized parameter" parameter(s) out of the 454 * ERROR chunk generated by sctp_verify_init(). Since the 455 * error cause code for "unknown parameter" and the 456 * "Unrecognized parameter" type is the same, we can 457 * construct the parameters in INIT ACK by copying the 458 * ERROR causes over. 459 */ 460 unk_param = (struct sctp_unrecognized_param *) 461 ((__u8 *)(err_chunk->chunk_hdr) + 462 sizeof(struct sctp_chunkhdr)); 463 /* Replace the cause code with the "Unrecognized parameter" 464 * parameter type. 465 */ 466 sctp_addto_chunk(repl, len, unk_param); 467 sctp_chunk_free(err_chunk); 468 } 469 470 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 471 472 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 473 474 /* 475 * Note: After sending out INIT ACK with the State Cookie parameter, 476 * "Z" MUST NOT allocate any resources, nor keep any states for the 477 * new association. Otherwise, "Z" will be vulnerable to resource 478 * attacks. 479 */ 480 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 481 482 return SCTP_DISPOSITION_DELETE_TCB; 483 484 nomem_init: 485 sctp_association_free(new_asoc); 486 nomem: 487 if (err_chunk) 488 sctp_chunk_free(err_chunk); 489 return SCTP_DISPOSITION_NOMEM; 490 } 491 492 /* 493 * Respond to a normal INIT ACK chunk. 494 * We are the side that is initiating the association. 495 * 496 * Section: 5.1 Normal Establishment of an Association, C 497 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init 498 * timer and leave COOKIE-WAIT state. "A" shall then send the State 499 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start 500 * the T1-cookie timer, and enter the COOKIE-ECHOED state. 501 * 502 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound 503 * DATA chunks, but it MUST be the first chunk in the packet and 504 * until the COOKIE ACK is returned the sender MUST NOT send any 505 * other packets to the peer. 506 * 507 * Verification Tag: 3.3.3 508 * If the value of the Initiate Tag in a received INIT ACK chunk is 509 * found to be 0, the receiver MUST treat it as an error and close the 510 * association by transmitting an ABORT. 511 * 512 * Inputs 513 * (endpoint, asoc, chunk) 514 * 515 * Outputs 516 * (asoc, reply_msg, msg_up, timers, counters) 517 * 518 * The return value is the disposition of the chunk. 519 */ 520 enum sctp_disposition sctp_sf_do_5_1C_ack(struct net *net, 521 const struct sctp_endpoint *ep, 522 const struct sctp_association *asoc, 523 const union sctp_subtype type, 524 void *arg, 525 struct sctp_cmd_seq *commands) 526 { 527 struct sctp_init_chunk *initchunk; 528 struct sctp_chunk *chunk = arg; 529 struct sctp_chunk *err_chunk; 530 struct sctp_packet *packet; 531 532 if (!sctp_vtag_verify(chunk, asoc)) 533 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 534 535 /* 6.10 Bundling 536 * An endpoint MUST NOT bundle INIT, INIT ACK or 537 * SHUTDOWN COMPLETE with any other chunks. 538 */ 539 if (!chunk->singleton) 540 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 541 542 /* Make sure that the INIT-ACK chunk has a valid length */ 543 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_initack_chunk))) 544 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 545 commands); 546 /* Grab the INIT header. */ 547 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 548 549 /* Verify the INIT chunk before processing it. */ 550 err_chunk = NULL; 551 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 552 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 553 &err_chunk)) { 554 555 enum sctp_error error = SCTP_ERROR_NO_RESOURCE; 556 557 /* This chunk contains fatal error. It is to be discarded. 558 * Send an ABORT, with causes. If there are no causes, 559 * then there wasn't enough memory. Just terminate 560 * the association. 561 */ 562 if (err_chunk) { 563 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 564 (__u8 *)(err_chunk->chunk_hdr) + 565 sizeof(struct sctp_chunkhdr), 566 ntohs(err_chunk->chunk_hdr->length) - 567 sizeof(struct sctp_chunkhdr)); 568 569 sctp_chunk_free(err_chunk); 570 571 if (packet) { 572 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 573 SCTP_PACKET(packet)); 574 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 575 error = SCTP_ERROR_INV_PARAM; 576 } 577 } 578 579 /* SCTP-AUTH, Section 6.3: 580 * It should be noted that if the receiver wants to tear 581 * down an association in an authenticated way only, the 582 * handling of malformed packets should not result in 583 * tearing down the association. 584 * 585 * This means that if we only want to abort associations 586 * in an authenticated way (i.e AUTH+ABORT), then we 587 * can't destroy this association just because the packet 588 * was malformed. 589 */ 590 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 591 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 592 593 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 594 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, 595 asoc, chunk->transport); 596 } 597 598 /* Tag the variable length parameters. Note that we never 599 * convert the parameters in an INIT chunk. 600 */ 601 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 602 603 initchunk = (struct sctp_init_chunk *)chunk->chunk_hdr; 604 605 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT, 606 SCTP_PEER_INIT(initchunk)); 607 608 /* SCTP-AUTH: generate the association shared keys so that 609 * we can potentially sign the COOKIE-ECHO. 610 */ 611 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL()); 612 613 /* Reset init error count upon receipt of INIT-ACK. */ 614 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 615 616 /* 5.1 C) "A" shall stop the T1-init timer and leave 617 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie 618 * timer, and enter the COOKIE-ECHOED state. 619 */ 620 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 621 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 622 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 623 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 624 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 625 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED)); 626 627 /* 5.1 C) "A" shall then send the State Cookie received in the 628 * INIT ACK chunk in a COOKIE ECHO chunk, ... 629 */ 630 /* If there is any errors to report, send the ERROR chunk generated 631 * for unknown parameters as well. 632 */ 633 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO, 634 SCTP_CHUNK(err_chunk)); 635 636 return SCTP_DISPOSITION_CONSUME; 637 } 638 639 static bool sctp_auth_chunk_verify(struct net *net, struct sctp_chunk *chunk, 640 const struct sctp_association *asoc) 641 { 642 struct sctp_chunk auth; 643 644 if (!chunk->auth_chunk) 645 return true; 646 647 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo 648 * is supposed to be authenticated and we have to do delayed 649 * authentication. We've just recreated the association using 650 * the information in the cookie and now it's much easier to 651 * do the authentication. 652 */ 653 654 /* Make sure that we and the peer are AUTH capable */ 655 if (!net->sctp.auth_enable || !asoc->peer.auth_capable) 656 return false; 657 658 /* set-up our fake chunk so that we can process it */ 659 auth.skb = chunk->auth_chunk; 660 auth.asoc = chunk->asoc; 661 auth.sctp_hdr = chunk->sctp_hdr; 662 auth.chunk_hdr = (struct sctp_chunkhdr *) 663 skb_push(chunk->auth_chunk, 664 sizeof(struct sctp_chunkhdr)); 665 skb_pull(chunk->auth_chunk, sizeof(struct sctp_chunkhdr)); 666 auth.transport = chunk->transport; 667 668 return sctp_sf_authenticate(asoc, &auth) == SCTP_IERROR_NO_ERROR; 669 } 670 671 /* 672 * Respond to a normal COOKIE ECHO chunk. 673 * We are the side that is being asked for an association. 674 * 675 * Section: 5.1 Normal Establishment of an Association, D 676 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply 677 * with a COOKIE ACK chunk after building a TCB and moving to 678 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with 679 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK 680 * chunk MUST be the first chunk in the packet. 681 * 682 * IMPLEMENTATION NOTE: An implementation may choose to send the 683 * Communication Up notification to the SCTP user upon reception 684 * of a valid COOKIE ECHO chunk. 685 * 686 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 687 * D) Rules for packet carrying a COOKIE ECHO 688 * 689 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the 690 * Initial Tag received in the INIT ACK. 691 * 692 * - The receiver of a COOKIE ECHO follows the procedures in Section 5. 693 * 694 * Inputs 695 * (endpoint, asoc, chunk) 696 * 697 * Outputs 698 * (asoc, reply_msg, msg_up, timers, counters) 699 * 700 * The return value is the disposition of the chunk. 701 */ 702 enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net, 703 const struct sctp_endpoint *ep, 704 const struct sctp_association *asoc, 705 const union sctp_subtype type, 706 void *arg, 707 struct sctp_cmd_seq *commands) 708 { 709 struct sctp_ulpevent *ev, *ai_ev = NULL, *auth_ev = NULL; 710 struct sctp_association *new_asoc; 711 struct sctp_init_chunk *peer_init; 712 struct sctp_chunk *chunk = arg; 713 struct sctp_chunk *err_chk_p; 714 struct sctp_chunk *repl; 715 struct sock *sk; 716 int error = 0; 717 718 if (asoc && !sctp_vtag_verify(chunk, asoc)) 719 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 720 721 /* If the packet is an OOTB packet which is temporarily on the 722 * control endpoint, respond with an ABORT. 723 */ 724 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 725 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 726 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 727 } 728 729 /* Make sure that the COOKIE_ECHO chunk has a valid length. 730 * In this case, we check that we have enough for at least a 731 * chunk header. More detailed verification is done 732 * in sctp_unpack_cookie(). 733 */ 734 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 735 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 736 commands); 737 738 /* If the endpoint is not listening or if the number of associations 739 * on the TCP-style socket exceed the max backlog, respond with an 740 * ABORT. 741 */ 742 sk = ep->base.sk; 743 if (!sctp_sstate(sk, LISTENING) || 744 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk))) 745 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 746 747 /* "Decode" the chunk. We have no optional parameters so we 748 * are in good shape. 749 */ 750 chunk->subh.cookie_hdr = 751 (struct sctp_signed_cookie *)chunk->skb->data; 752 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 753 sizeof(struct sctp_chunkhdr))) 754 goto nomem; 755 756 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint 757 * "Z" will reply with a COOKIE ACK chunk after building a TCB 758 * and moving to the ESTABLISHED state. 759 */ 760 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 761 &err_chk_p); 762 763 /* FIXME: 764 * If the re-build failed, what is the proper error path 765 * from here? 766 * 767 * [We should abort the association. --piggy] 768 */ 769 if (!new_asoc) { 770 /* FIXME: Several errors are possible. A bad cookie should 771 * be silently discarded, but think about logging it too. 772 */ 773 switch (error) { 774 case -SCTP_IERROR_NOMEM: 775 goto nomem; 776 777 case -SCTP_IERROR_STALE_COOKIE: 778 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 779 err_chk_p); 780 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 781 782 case -SCTP_IERROR_BAD_SIG: 783 default: 784 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 785 } 786 } 787 788 if (security_sctp_assoc_request(new_asoc, chunk->head_skb ?: chunk->skb)) { 789 sctp_association_free(new_asoc); 790 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 791 } 792 793 /* Delay state machine commands until later. 794 * 795 * Re-build the bind address for the association is done in 796 * the sctp_unpack_cookie() already. 797 */ 798 /* This is a brand-new association, so these are not yet side 799 * effects--it is safe to run them here. 800 */ 801 peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1); 802 if (!sctp_process_init(new_asoc, chunk, 803 &chunk->subh.cookie_hdr->c.peer_addr, 804 peer_init, GFP_ATOMIC)) 805 goto nomem_init; 806 807 /* SCTP-AUTH: Now that we've populate required fields in 808 * sctp_process_init, set up the association shared keys as 809 * necessary so that we can potentially authenticate the ACK 810 */ 811 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC); 812 if (error) 813 goto nomem_init; 814 815 if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) { 816 sctp_association_free(new_asoc); 817 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 818 } 819 820 repl = sctp_make_cookie_ack(new_asoc, chunk); 821 if (!repl) 822 goto nomem_init; 823 824 /* RFC 2960 5.1 Normal Establishment of an Association 825 * 826 * D) IMPLEMENTATION NOTE: An implementation may choose to 827 * send the Communication Up notification to the SCTP user 828 * upon reception of a valid COOKIE ECHO chunk. 829 */ 830 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0, 831 new_asoc->c.sinit_num_ostreams, 832 new_asoc->c.sinit_max_instreams, 833 NULL, GFP_ATOMIC); 834 if (!ev) 835 goto nomem_ev; 836 837 /* Sockets API Draft Section 5.3.1.6 838 * When a peer sends a Adaptation Layer Indication parameter , SCTP 839 * delivers this notification to inform the application that of the 840 * peers requested adaptation layer. 841 */ 842 if (new_asoc->peer.adaptation_ind) { 843 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc, 844 GFP_ATOMIC); 845 if (!ai_ev) 846 goto nomem_aiev; 847 } 848 849 if (!new_asoc->peer.auth_capable) { 850 auth_ev = sctp_ulpevent_make_authkey(new_asoc, 0, 851 SCTP_AUTH_NO_AUTH, 852 GFP_ATOMIC); 853 if (!auth_ev) 854 goto nomem_authev; 855 } 856 857 /* Add all the state machine commands now since we've created 858 * everything. This way we don't introduce memory corruptions 859 * during side-effect processing and correctly count established 860 * associations. 861 */ 862 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 863 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 864 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 865 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 866 SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS); 867 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 868 869 if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 870 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 871 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 872 873 /* This will send the COOKIE ACK */ 874 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 875 876 /* Queue the ASSOC_CHANGE event */ 877 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 878 879 /* Send up the Adaptation Layer Indication event */ 880 if (ai_ev) 881 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 882 SCTP_ULPEVENT(ai_ev)); 883 884 if (auth_ev) 885 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 886 SCTP_ULPEVENT(auth_ev)); 887 888 return SCTP_DISPOSITION_CONSUME; 889 890 nomem_authev: 891 if (ai_ev) 892 sctp_ulpevent_free(ai_ev); 893 nomem_aiev: 894 sctp_ulpevent_free(ev); 895 nomem_ev: 896 sctp_chunk_free(repl); 897 nomem_init: 898 sctp_association_free(new_asoc); 899 nomem: 900 return SCTP_DISPOSITION_NOMEM; 901 } 902 903 /* 904 * Respond to a normal COOKIE ACK chunk. 905 * We are the side that is asking for an association. 906 * 907 * RFC 2960 5.1 Normal Establishment of an Association 908 * 909 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the 910 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie 911 * timer. It may also notify its ULP about the successful 912 * establishment of the association with a Communication Up 913 * notification (see Section 10). 914 * 915 * Verification Tag: 916 * Inputs 917 * (endpoint, asoc, chunk) 918 * 919 * Outputs 920 * (asoc, reply_msg, msg_up, timers, counters) 921 * 922 * The return value is the disposition of the chunk. 923 */ 924 enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net, 925 const struct sctp_endpoint *ep, 926 const struct sctp_association *asoc, 927 const union sctp_subtype type, 928 void *arg, 929 struct sctp_cmd_seq *commands) 930 { 931 struct sctp_chunk *chunk = arg; 932 struct sctp_ulpevent *ev; 933 934 if (!sctp_vtag_verify(chunk, asoc)) 935 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 936 937 /* Set peer label for connection. */ 938 if (security_sctp_assoc_established((struct sctp_association *)asoc, 939 chunk->head_skb ?: chunk->skb)) 940 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 941 942 /* Verify that the chunk length for the COOKIE-ACK is OK. 943 * If we don't do this, any bundled chunks may be junked. 944 */ 945 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 946 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 947 commands); 948 949 /* Reset init error count upon receipt of COOKIE-ACK, 950 * to avoid problems with the management of this 951 * counter in stale cookie situations when a transition back 952 * from the COOKIE-ECHOED state to the COOKIE-WAIT 953 * state is performed. 954 */ 955 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 956 957 /* RFC 2960 5.1 Normal Establishment of an Association 958 * 959 * E) Upon reception of the COOKIE ACK, endpoint "A" will move 960 * from the COOKIE-ECHOED state to the ESTABLISHED state, 961 * stopping the T1-cookie timer. 962 */ 963 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 964 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 965 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 966 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 967 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 968 SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS); 969 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 970 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 971 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 972 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 973 974 /* It may also notify its ULP about the successful 975 * establishment of the association with a Communication Up 976 * notification (see Section 10). 977 */ 978 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 979 0, asoc->c.sinit_num_ostreams, 980 asoc->c.sinit_max_instreams, 981 NULL, GFP_ATOMIC); 982 983 if (!ev) 984 goto nomem; 985 986 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 987 988 /* Sockets API Draft Section 5.3.1.6 989 * When a peer sends a Adaptation Layer Indication parameter , SCTP 990 * delivers this notification to inform the application that of the 991 * peers requested adaptation layer. 992 */ 993 if (asoc->peer.adaptation_ind) { 994 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC); 995 if (!ev) 996 goto nomem; 997 998 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 999 SCTP_ULPEVENT(ev)); 1000 } 1001 1002 if (!asoc->peer.auth_capable) { 1003 ev = sctp_ulpevent_make_authkey(asoc, 0, SCTP_AUTH_NO_AUTH, 1004 GFP_ATOMIC); 1005 if (!ev) 1006 goto nomem; 1007 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1008 SCTP_ULPEVENT(ev)); 1009 } 1010 1011 return SCTP_DISPOSITION_CONSUME; 1012 nomem: 1013 return SCTP_DISPOSITION_NOMEM; 1014 } 1015 1016 /* Generate and sendout a heartbeat packet. */ 1017 static enum sctp_disposition sctp_sf_heartbeat( 1018 const struct sctp_endpoint *ep, 1019 const struct sctp_association *asoc, 1020 const union sctp_subtype type, 1021 void *arg, 1022 struct sctp_cmd_seq *commands) 1023 { 1024 struct sctp_transport *transport = (struct sctp_transport *) arg; 1025 struct sctp_chunk *reply; 1026 1027 /* Send a heartbeat to our peer. */ 1028 reply = sctp_make_heartbeat(asoc, transport, 0); 1029 if (!reply) 1030 return SCTP_DISPOSITION_NOMEM; 1031 1032 /* Set rto_pending indicating that an RTT measurement 1033 * is started with this heartbeat chunk. 1034 */ 1035 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING, 1036 SCTP_TRANSPORT(transport)); 1037 1038 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1039 return SCTP_DISPOSITION_CONSUME; 1040 } 1041 1042 /* Generate a HEARTBEAT packet on the given transport. */ 1043 enum sctp_disposition sctp_sf_sendbeat_8_3(struct net *net, 1044 const struct sctp_endpoint *ep, 1045 const struct sctp_association *asoc, 1046 const union sctp_subtype type, 1047 void *arg, 1048 struct sctp_cmd_seq *commands) 1049 { 1050 struct sctp_transport *transport = (struct sctp_transport *) arg; 1051 1052 if (asoc->overall_error_count >= asoc->max_retrans) { 1053 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 1054 SCTP_ERROR(ETIMEDOUT)); 1055 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 1056 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 1057 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 1058 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 1059 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 1060 return SCTP_DISPOSITION_DELETE_TCB; 1061 } 1062 1063 /* Section 3.3.5. 1064 * The Sender-specific Heartbeat Info field should normally include 1065 * information about the sender's current time when this HEARTBEAT 1066 * chunk is sent and the destination transport address to which this 1067 * HEARTBEAT is sent (see Section 8.3). 1068 */ 1069 1070 if (transport->param_flags & SPP_HB_ENABLE) { 1071 if (SCTP_DISPOSITION_NOMEM == 1072 sctp_sf_heartbeat(ep, asoc, type, arg, 1073 commands)) 1074 return SCTP_DISPOSITION_NOMEM; 1075 1076 /* Set transport error counter and association error counter 1077 * when sending heartbeat. 1078 */ 1079 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 1080 SCTP_TRANSPORT(transport)); 1081 } 1082 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE, 1083 SCTP_TRANSPORT(transport)); 1084 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE, 1085 SCTP_TRANSPORT(transport)); 1086 1087 return SCTP_DISPOSITION_CONSUME; 1088 } 1089 1090 /* resend asoc strreset_chunk. */ 1091 enum sctp_disposition sctp_sf_send_reconf(struct net *net, 1092 const struct sctp_endpoint *ep, 1093 const struct sctp_association *asoc, 1094 const union sctp_subtype type, 1095 void *arg, 1096 struct sctp_cmd_seq *commands) 1097 { 1098 struct sctp_transport *transport = arg; 1099 1100 if (asoc->overall_error_count >= asoc->max_retrans) { 1101 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 1102 SCTP_ERROR(ETIMEDOUT)); 1103 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 1104 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 1105 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 1106 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 1107 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 1108 return SCTP_DISPOSITION_DELETE_TCB; 1109 } 1110 1111 sctp_chunk_hold(asoc->strreset_chunk); 1112 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1113 SCTP_CHUNK(asoc->strreset_chunk)); 1114 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 1115 1116 return SCTP_DISPOSITION_CONSUME; 1117 } 1118 1119 /* send hb chunk with padding for PLPMUTD. */ 1120 enum sctp_disposition sctp_sf_send_probe(struct net *net, 1121 const struct sctp_endpoint *ep, 1122 const struct sctp_association *asoc, 1123 const union sctp_subtype type, 1124 void *arg, 1125 struct sctp_cmd_seq *commands) 1126 { 1127 struct sctp_transport *transport = (struct sctp_transport *)arg; 1128 struct sctp_chunk *reply; 1129 1130 if (!sctp_transport_pl_enabled(transport)) 1131 return SCTP_DISPOSITION_CONSUME; 1132 1133 sctp_transport_pl_send(transport); 1134 reply = sctp_make_heartbeat(asoc, transport, transport->pl.probe_size); 1135 if (!reply) 1136 return SCTP_DISPOSITION_NOMEM; 1137 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1138 sctp_add_cmd_sf(commands, SCTP_CMD_PROBE_TIMER_UPDATE, 1139 SCTP_TRANSPORT(transport)); 1140 1141 return SCTP_DISPOSITION_CONSUME; 1142 } 1143 1144 /* 1145 * Process an heartbeat request. 1146 * 1147 * Section: 8.3 Path Heartbeat 1148 * The receiver of the HEARTBEAT should immediately respond with a 1149 * HEARTBEAT ACK that contains the Heartbeat Information field copied 1150 * from the received HEARTBEAT chunk. 1151 * 1152 * Verification Tag: 8.5 Verification Tag [Normal verification] 1153 * When receiving an SCTP packet, the endpoint MUST ensure that the 1154 * value in the Verification Tag field of the received SCTP packet 1155 * matches its own Tag. If the received Verification Tag value does not 1156 * match the receiver's own tag value, the receiver shall silently 1157 * discard the packet and shall not process it any further except for 1158 * those cases listed in Section 8.5.1 below. 1159 * 1160 * Inputs 1161 * (endpoint, asoc, chunk) 1162 * 1163 * Outputs 1164 * (asoc, reply_msg, msg_up, timers, counters) 1165 * 1166 * The return value is the disposition of the chunk. 1167 */ 1168 enum sctp_disposition sctp_sf_beat_8_3(struct net *net, 1169 const struct sctp_endpoint *ep, 1170 const struct sctp_association *asoc, 1171 const union sctp_subtype type, 1172 void *arg, struct sctp_cmd_seq *commands) 1173 { 1174 struct sctp_paramhdr *param_hdr; 1175 struct sctp_chunk *chunk = arg; 1176 struct sctp_chunk *reply; 1177 size_t paylen = 0; 1178 1179 if (!sctp_vtag_verify(chunk, asoc)) 1180 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1181 1182 /* Make sure that the HEARTBEAT chunk has a valid length. */ 1183 if (!sctp_chunk_length_valid(chunk, 1184 sizeof(struct sctp_heartbeat_chunk))) 1185 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1186 commands); 1187 1188 /* 8.3 The receiver of the HEARTBEAT should immediately 1189 * respond with a HEARTBEAT ACK that contains the Heartbeat 1190 * Information field copied from the received HEARTBEAT chunk. 1191 */ 1192 chunk->subh.hb_hdr = (struct sctp_heartbeathdr *)chunk->skb->data; 1193 param_hdr = (struct sctp_paramhdr *)chunk->subh.hb_hdr; 1194 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(struct sctp_chunkhdr); 1195 1196 if (ntohs(param_hdr->length) > paylen) 1197 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 1198 param_hdr, commands); 1199 1200 if (!pskb_pull(chunk->skb, paylen)) 1201 goto nomem; 1202 1203 reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen); 1204 if (!reply) 1205 goto nomem; 1206 1207 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1208 return SCTP_DISPOSITION_CONSUME; 1209 1210 nomem: 1211 return SCTP_DISPOSITION_NOMEM; 1212 } 1213 1214 /* 1215 * Process the returning HEARTBEAT ACK. 1216 * 1217 * Section: 8.3 Path Heartbeat 1218 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT 1219 * should clear the error counter of the destination transport 1220 * address to which the HEARTBEAT was sent, and mark the destination 1221 * transport address as active if it is not so marked. The endpoint may 1222 * optionally report to the upper layer when an inactive destination 1223 * address is marked as active due to the reception of the latest 1224 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also 1225 * clear the association overall error count as well (as defined 1226 * in section 8.1). 1227 * 1228 * The receiver of the HEARTBEAT ACK should also perform an RTT 1229 * measurement for that destination transport address using the time 1230 * value carried in the HEARTBEAT ACK chunk. 1231 * 1232 * Verification Tag: 8.5 Verification Tag [Normal verification] 1233 * 1234 * Inputs 1235 * (endpoint, asoc, chunk) 1236 * 1237 * Outputs 1238 * (asoc, reply_msg, msg_up, timers, counters) 1239 * 1240 * The return value is the disposition of the chunk. 1241 */ 1242 enum sctp_disposition sctp_sf_backbeat_8_3(struct net *net, 1243 const struct sctp_endpoint *ep, 1244 const struct sctp_association *asoc, 1245 const union sctp_subtype type, 1246 void *arg, 1247 struct sctp_cmd_seq *commands) 1248 { 1249 struct sctp_sender_hb_info *hbinfo; 1250 struct sctp_chunk *chunk = arg; 1251 struct sctp_transport *link; 1252 unsigned long max_interval; 1253 union sctp_addr from_addr; 1254 1255 if (!sctp_vtag_verify(chunk, asoc)) 1256 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1257 1258 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */ 1259 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr) + 1260 sizeof(*hbinfo))) 1261 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1262 commands); 1263 1264 hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data; 1265 /* Make sure that the length of the parameter is what we expect */ 1266 if (ntohs(hbinfo->param_hdr.length) != sizeof(*hbinfo)) 1267 return SCTP_DISPOSITION_DISCARD; 1268 1269 from_addr = hbinfo->daddr; 1270 link = sctp_assoc_lookup_paddr(asoc, &from_addr); 1271 1272 /* This should never happen, but lets log it if so. */ 1273 if (unlikely(!link)) { 1274 if (from_addr.sa.sa_family == AF_INET6) { 1275 net_warn_ratelimited("%s association %p could not find address %pI6\n", 1276 __func__, 1277 asoc, 1278 &from_addr.v6.sin6_addr); 1279 } else { 1280 net_warn_ratelimited("%s association %p could not find address %pI4\n", 1281 __func__, 1282 asoc, 1283 &from_addr.v4.sin_addr.s_addr); 1284 } 1285 return SCTP_DISPOSITION_DISCARD; 1286 } 1287 1288 /* Validate the 64-bit random nonce. */ 1289 if (hbinfo->hb_nonce != link->hb_nonce) 1290 return SCTP_DISPOSITION_DISCARD; 1291 1292 if (hbinfo->probe_size) { 1293 if (hbinfo->probe_size != link->pl.probe_size || 1294 !sctp_transport_pl_enabled(link)) 1295 return SCTP_DISPOSITION_DISCARD; 1296 1297 if (sctp_transport_pl_recv(link)) 1298 return SCTP_DISPOSITION_CONSUME; 1299 1300 return sctp_sf_send_probe(net, ep, asoc, type, link, commands); 1301 } 1302 1303 max_interval = link->hbinterval + link->rto; 1304 1305 /* Check if the timestamp looks valid. */ 1306 if (time_after(hbinfo->sent_at, jiffies) || 1307 time_after(jiffies, hbinfo->sent_at + max_interval)) { 1308 pr_debug("%s: HEARTBEAT ACK with invalid timestamp received " 1309 "for transport:%p\n", __func__, link); 1310 1311 return SCTP_DISPOSITION_DISCARD; 1312 } 1313 1314 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of 1315 * the HEARTBEAT should clear the error counter of the 1316 * destination transport address to which the HEARTBEAT was 1317 * sent and mark the destination transport address as active if 1318 * it is not so marked. 1319 */ 1320 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); 1321 1322 return SCTP_DISPOSITION_CONSUME; 1323 } 1324 1325 /* Helper function to send out an abort for the restart 1326 * condition. 1327 */ 1328 static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa, 1329 struct sctp_chunk *init, 1330 struct sctp_cmd_seq *commands) 1331 { 1332 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); 1333 union sctp_addr_param *addrparm; 1334 struct sctp_errhdr *errhdr; 1335 char buffer[sizeof(*errhdr) + sizeof(*addrparm)]; 1336 struct sctp_endpoint *ep; 1337 struct sctp_packet *pkt; 1338 int len; 1339 1340 /* Build the error on the stack. We are way to malloc crazy 1341 * throughout the code today. 1342 */ 1343 errhdr = (struct sctp_errhdr *)buffer; 1344 addrparm = (union sctp_addr_param *)(errhdr + 1); 1345 1346 /* Copy into a parm format. */ 1347 len = af->to_addr_param(ssa, addrparm); 1348 len += sizeof(*errhdr); 1349 1350 errhdr->cause = SCTP_ERROR_RESTART; 1351 errhdr->length = htons(len); 1352 1353 /* Assign to the control socket. */ 1354 ep = sctp_sk(net->sctp.ctl_sock)->ep; 1355 1356 /* Association is NULL since this may be a restart attack and we 1357 * want to send back the attacker's vtag. 1358 */ 1359 pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len); 1360 1361 if (!pkt) 1362 goto out; 1363 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); 1364 1365 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1366 1367 /* Discard the rest of the inbound packet. */ 1368 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 1369 1370 out: 1371 /* Even if there is no memory, treat as a failure so 1372 * the packet will get dropped. 1373 */ 1374 return 0; 1375 } 1376 1377 static bool list_has_sctp_addr(const struct list_head *list, 1378 union sctp_addr *ipaddr) 1379 { 1380 struct sctp_transport *addr; 1381 1382 list_for_each_entry(addr, list, transports) { 1383 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr)) 1384 return true; 1385 } 1386 1387 return false; 1388 } 1389 /* A restart is occurring, check to make sure no new addresses 1390 * are being added as we may be under a takeover attack. 1391 */ 1392 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, 1393 const struct sctp_association *asoc, 1394 struct sctp_chunk *init, 1395 struct sctp_cmd_seq *commands) 1396 { 1397 struct net *net = new_asoc->base.net; 1398 struct sctp_transport *new_addr; 1399 int ret = 1; 1400 1401 /* Implementor's Guide - Section 5.2.2 1402 * ... 1403 * Before responding the endpoint MUST check to see if the 1404 * unexpected INIT adds new addresses to the association. If new 1405 * addresses are added to the association, the endpoint MUST respond 1406 * with an ABORT.. 1407 */ 1408 1409 /* Search through all current addresses and make sure 1410 * we aren't adding any new ones. 1411 */ 1412 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list, 1413 transports) { 1414 if (!list_has_sctp_addr(&asoc->peer.transport_addr_list, 1415 &new_addr->ipaddr)) { 1416 sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init, 1417 commands); 1418 ret = 0; 1419 break; 1420 } 1421 } 1422 1423 /* Return success if all addresses were found. */ 1424 return ret; 1425 } 1426 1427 /* Populate the verification/tie tags based on overlapping INIT 1428 * scenario. 1429 * 1430 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. 1431 */ 1432 static void sctp_tietags_populate(struct sctp_association *new_asoc, 1433 const struct sctp_association *asoc) 1434 { 1435 switch (asoc->state) { 1436 1437 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ 1438 1439 case SCTP_STATE_COOKIE_WAIT: 1440 new_asoc->c.my_vtag = asoc->c.my_vtag; 1441 new_asoc->c.my_ttag = asoc->c.my_vtag; 1442 new_asoc->c.peer_ttag = 0; 1443 break; 1444 1445 case SCTP_STATE_COOKIE_ECHOED: 1446 new_asoc->c.my_vtag = asoc->c.my_vtag; 1447 new_asoc->c.my_ttag = asoc->c.my_vtag; 1448 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1449 break; 1450 1451 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, 1452 * COOKIE-WAIT and SHUTDOWN-ACK-SENT 1453 */ 1454 default: 1455 new_asoc->c.my_ttag = asoc->c.my_vtag; 1456 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1457 break; 1458 } 1459 1460 /* Other parameters for the endpoint SHOULD be copied from the 1461 * existing parameters of the association (e.g. number of 1462 * outbound streams) into the INIT ACK and cookie. 1463 */ 1464 new_asoc->rwnd = asoc->rwnd; 1465 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; 1466 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; 1467 new_asoc->c.initial_tsn = asoc->c.initial_tsn; 1468 } 1469 1470 /* 1471 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO 1472 * handling action. 1473 * 1474 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. 1475 * 1476 * Returns value representing action to be taken. These action values 1477 * correspond to Action/Description values in RFC 2960, Table 2. 1478 */ 1479 static char sctp_tietags_compare(struct sctp_association *new_asoc, 1480 const struct sctp_association *asoc) 1481 { 1482 /* In this case, the peer may have restarted. */ 1483 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1484 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && 1485 (asoc->c.my_vtag == new_asoc->c.my_ttag) && 1486 (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) 1487 return 'A'; 1488 1489 /* Collision case B. */ 1490 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1491 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || 1492 (0 == asoc->c.peer_vtag))) { 1493 return 'B'; 1494 } 1495 1496 /* Collision case D. */ 1497 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1498 (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) 1499 return 'D'; 1500 1501 /* Collision case C. */ 1502 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1503 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && 1504 (0 == new_asoc->c.my_ttag) && 1505 (0 == new_asoc->c.peer_ttag)) 1506 return 'C'; 1507 1508 /* No match to any of the special cases; discard this packet. */ 1509 return 'E'; 1510 } 1511 1512 /* Common helper routine for both duplicate and simultaneous INIT 1513 * chunk handling. 1514 */ 1515 static enum sctp_disposition sctp_sf_do_unexpected_init( 1516 struct net *net, 1517 const struct sctp_endpoint *ep, 1518 const struct sctp_association *asoc, 1519 const union sctp_subtype type, 1520 void *arg, 1521 struct sctp_cmd_seq *commands) 1522 { 1523 struct sctp_chunk *chunk = arg, *repl, *err_chunk; 1524 struct sctp_unrecognized_param *unk_param; 1525 struct sctp_association *new_asoc; 1526 enum sctp_disposition retval; 1527 struct sctp_packet *packet; 1528 int len; 1529 1530 /* 6.10 Bundling 1531 * An endpoint MUST NOT bundle INIT, INIT ACK or 1532 * SHUTDOWN COMPLETE with any other chunks. 1533 * 1534 * IG Section 2.11.2 1535 * Furthermore, we require that the receiver of an INIT chunk MUST 1536 * enforce these rules by silently discarding an arriving packet 1537 * with an INIT chunk that is bundled with other chunks. 1538 */ 1539 if (!chunk->singleton) 1540 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1541 1542 /* Make sure that the INIT chunk has a valid length. */ 1543 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk))) 1544 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1545 1546 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 1547 * Tag. 1548 */ 1549 if (chunk->sctp_hdr->vtag != 0) 1550 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 1551 1552 if (SCTP_INPUT_CB(chunk->skb)->encap_port != chunk->transport->encap_port) 1553 return sctp_sf_new_encap_port(net, ep, asoc, type, arg, commands); 1554 1555 /* Grab the INIT header. */ 1556 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 1557 1558 /* Tag the variable length parameters. */ 1559 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 1560 1561 if (asoc->state >= SCTP_STATE_ESTABLISHED) { 1562 /* Discard INIT matching peer vtag after handshake completion (stale INIT). */ 1563 if (ntohl(chunk->subh.init_hdr->init_tag) == asoc->peer.i.init_tag) 1564 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1565 } 1566 1567 /* Verify the INIT chunk before processing it. */ 1568 err_chunk = NULL; 1569 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 1570 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 1571 &err_chunk)) { 1572 /* This chunk contains fatal error. It is to be discarded. 1573 * Send an ABORT, with causes if there is any. 1574 */ 1575 if (err_chunk) { 1576 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 1577 (__u8 *)(err_chunk->chunk_hdr) + 1578 sizeof(struct sctp_chunkhdr), 1579 ntohs(err_chunk->chunk_hdr->length) - 1580 sizeof(struct sctp_chunkhdr)); 1581 1582 if (packet) { 1583 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 1584 SCTP_PACKET(packet)); 1585 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1586 retval = SCTP_DISPOSITION_CONSUME; 1587 } else { 1588 retval = SCTP_DISPOSITION_NOMEM; 1589 } 1590 goto cleanup; 1591 } else { 1592 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 1593 commands); 1594 } 1595 } 1596 1597 /* 1598 * Other parameters for the endpoint SHOULD be copied from the 1599 * existing parameters of the association (e.g. number of 1600 * outbound streams) into the INIT ACK and cookie. 1601 * FIXME: We are copying parameters from the endpoint not the 1602 * association. 1603 */ 1604 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 1605 if (!new_asoc) 1606 goto nomem; 1607 1608 /* Update socket peer label if first association. */ 1609 if (security_sctp_assoc_request(new_asoc, chunk->skb)) { 1610 sctp_association_free(new_asoc); 1611 if (err_chunk) 1612 sctp_chunk_free(err_chunk); 1613 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1614 } 1615 1616 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 1617 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0) 1618 goto nomem; 1619 1620 /* In the outbound INIT ACK the endpoint MUST copy its current 1621 * Verification Tag and Peers Verification tag into a reserved 1622 * place (local tie-tag and per tie-tag) within the state cookie. 1623 */ 1624 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 1625 (struct sctp_init_chunk *)chunk->chunk_hdr, 1626 GFP_ATOMIC)) 1627 goto nomem; 1628 1629 /* Make sure no new addresses are being added during the 1630 * restart. Do not do this check for COOKIE-WAIT state, 1631 * since there are no peer addresses to check against. 1632 * Upon return an ABORT will have been sent if needed. 1633 */ 1634 if (!sctp_state(asoc, COOKIE_WAIT)) { 1635 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, 1636 commands)) { 1637 retval = SCTP_DISPOSITION_CONSUME; 1638 goto nomem_retval; 1639 } 1640 } 1641 1642 sctp_tietags_populate(new_asoc, asoc); 1643 1644 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 1645 1646 /* If there are errors need to be reported for unknown parameters, 1647 * make sure to reserve enough room in the INIT ACK for them. 1648 */ 1649 len = 0; 1650 if (err_chunk) { 1651 len = ntohs(err_chunk->chunk_hdr->length) - 1652 sizeof(struct sctp_chunkhdr); 1653 } 1654 1655 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 1656 if (!repl) 1657 goto nomem; 1658 1659 /* If there are errors need to be reported for unknown parameters, 1660 * include them in the outgoing INIT ACK as "Unrecognized parameter" 1661 * parameter. 1662 */ 1663 if (err_chunk) { 1664 /* Get the "Unrecognized parameter" parameter(s) out of the 1665 * ERROR chunk generated by sctp_verify_init(). Since the 1666 * error cause code for "unknown parameter" and the 1667 * "Unrecognized parameter" type is the same, we can 1668 * construct the parameters in INIT ACK by copying the 1669 * ERROR causes over. 1670 */ 1671 unk_param = (struct sctp_unrecognized_param *) 1672 ((__u8 *)(err_chunk->chunk_hdr) + 1673 sizeof(struct sctp_chunkhdr)); 1674 /* Replace the cause code with the "Unrecognized parameter" 1675 * parameter type. 1676 */ 1677 sctp_addto_chunk(repl, len, unk_param); 1678 sctp_chunk_free(err_chunk); 1679 } 1680 1681 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1682 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1683 1684 /* 1685 * Note: After sending out INIT ACK with the State Cookie parameter, 1686 * "Z" MUST NOT allocate any resources for this new association. 1687 * Otherwise, "Z" will be vulnerable to resource attacks. 1688 */ 1689 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1690 retval = SCTP_DISPOSITION_CONSUME; 1691 1692 return retval; 1693 1694 nomem: 1695 retval = SCTP_DISPOSITION_NOMEM; 1696 nomem_retval: 1697 if (new_asoc) 1698 sctp_association_free(new_asoc); 1699 cleanup: 1700 if (err_chunk) 1701 sctp_chunk_free(err_chunk); 1702 return retval; 1703 } 1704 1705 /* 1706 * Handle simultaneous INIT. 1707 * This means we started an INIT and then we got an INIT request from 1708 * our peer. 1709 * 1710 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) 1711 * This usually indicates an initialization collision, i.e., each 1712 * endpoint is attempting, at about the same time, to establish an 1713 * association with the other endpoint. 1714 * 1715 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an 1716 * endpoint MUST respond with an INIT ACK using the same parameters it 1717 * sent in its original INIT chunk (including its Verification Tag, 1718 * unchanged). These original parameters are combined with those from the 1719 * newly received INIT chunk. The endpoint shall also generate a State 1720 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its 1721 * INIT to calculate the State Cookie. 1722 * 1723 * After that, the endpoint MUST NOT change its state, the T1-init 1724 * timer shall be left running and the corresponding TCB MUST NOT be 1725 * destroyed. The normal procedures for handling State Cookies when 1726 * a TCB exists will resolve the duplicate INITs to a single association. 1727 * 1728 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate 1729 * its Tie-Tags with the Tag information of itself and its peer (see 1730 * section 5.2.2 for a description of the Tie-Tags). 1731 * 1732 * Verification Tag: Not explicit, but an INIT can not have a valid 1733 * verification tag, so we skip the check. 1734 * 1735 * Inputs 1736 * (endpoint, asoc, chunk) 1737 * 1738 * Outputs 1739 * (asoc, reply_msg, msg_up, timers, counters) 1740 * 1741 * The return value is the disposition of the chunk. 1742 */ 1743 enum sctp_disposition sctp_sf_do_5_2_1_siminit( 1744 struct net *net, 1745 const struct sctp_endpoint *ep, 1746 const struct sctp_association *asoc, 1747 const union sctp_subtype type, 1748 void *arg, 1749 struct sctp_cmd_seq *commands) 1750 { 1751 /* Call helper to do the real work for both simultaneous and 1752 * duplicate INIT chunk handling. 1753 */ 1754 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1755 } 1756 1757 /* 1758 * Handle duplicated INIT messages. These are usually delayed 1759 * restransmissions. 1760 * 1761 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, 1762 * COOKIE-ECHOED and COOKIE-WAIT 1763 * 1764 * Unless otherwise stated, upon reception of an unexpected INIT for 1765 * this association, the endpoint shall generate an INIT ACK with a 1766 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its 1767 * current Verification Tag and peer's Verification Tag into a reserved 1768 * place within the state cookie. We shall refer to these locations as 1769 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet 1770 * containing this INIT ACK MUST carry a Verification Tag value equal to 1771 * the Initiation Tag found in the unexpected INIT. And the INIT ACK 1772 * MUST contain a new Initiation Tag (randomly generated see Section 1773 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the 1774 * existing parameters of the association (e.g. number of outbound 1775 * streams) into the INIT ACK and cookie. 1776 * 1777 * After sending out the INIT ACK, the endpoint shall take no further 1778 * actions, i.e., the existing association, including its current state, 1779 * and the corresponding TCB MUST NOT be changed. 1780 * 1781 * Note: Only when a TCB exists and the association is not in a COOKIE- 1782 * WAIT state are the Tie-Tags populated. For a normal association INIT 1783 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be 1784 * set to 0 (indicating that no previous TCB existed). The INIT ACK and 1785 * State Cookie are populated as specified in section 5.2.1. 1786 * 1787 * Verification Tag: Not specified, but an INIT has no way of knowing 1788 * what the verification tag could be, so we ignore it. 1789 * 1790 * Inputs 1791 * (endpoint, asoc, chunk) 1792 * 1793 * Outputs 1794 * (asoc, reply_msg, msg_up, timers, counters) 1795 * 1796 * The return value is the disposition of the chunk. 1797 */ 1798 enum sctp_disposition sctp_sf_do_5_2_2_dupinit( 1799 struct net *net, 1800 const struct sctp_endpoint *ep, 1801 const struct sctp_association *asoc, 1802 const union sctp_subtype type, 1803 void *arg, 1804 struct sctp_cmd_seq *commands) 1805 { 1806 /* Call helper to do the real work for both simultaneous and 1807 * duplicate INIT chunk handling. 1808 */ 1809 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1810 } 1811 1812 1813 /* 1814 * Unexpected INIT-ACK handler. 1815 * 1816 * Section 5.2.3 1817 * If an INIT ACK received by an endpoint in any state other than the 1818 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk. 1819 * An unexpected INIT ACK usually indicates the processing of an old or 1820 * duplicated INIT chunk. 1821 */ 1822 enum sctp_disposition sctp_sf_do_5_2_3_initack( 1823 struct net *net, 1824 const struct sctp_endpoint *ep, 1825 const struct sctp_association *asoc, 1826 const union sctp_subtype type, 1827 void *arg, 1828 struct sctp_cmd_seq *commands) 1829 { 1830 /* Per the above section, we'll discard the chunk if we have an 1831 * endpoint. If this is an OOTB INIT-ACK, treat it as such. 1832 */ 1833 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) 1834 return sctp_sf_ootb(net, ep, asoc, type, arg, commands); 1835 else 1836 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 1837 } 1838 1839 static int sctp_sf_do_assoc_update(struct sctp_association *asoc, 1840 struct sctp_association *new, 1841 struct sctp_cmd_seq *cmds) 1842 { 1843 struct net *net = asoc->base.net; 1844 struct sctp_chunk *abort; 1845 1846 if (!sctp_assoc_update(asoc, new)) 1847 return 0; 1848 1849 abort = sctp_make_abort(asoc, NULL, sizeof(struct sctp_errhdr)); 1850 if (abort) { 1851 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 1852 sctp_add_cmd_sf(cmds, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 1853 } 1854 sctp_add_cmd_sf(cmds, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNABORTED)); 1855 sctp_add_cmd_sf(cmds, SCTP_CMD_ASSOC_FAILED, 1856 SCTP_PERR(SCTP_ERROR_RSRC_LOW)); 1857 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 1858 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 1859 1860 return -ENOMEM; 1861 } 1862 1863 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') 1864 * 1865 * Section 5.2.4 1866 * A) In this case, the peer may have restarted. 1867 */ 1868 static enum sctp_disposition sctp_sf_do_dupcook_a( 1869 struct net *net, 1870 const struct sctp_endpoint *ep, 1871 const struct sctp_association *asoc, 1872 struct sctp_chunk *chunk, 1873 struct sctp_cmd_seq *commands, 1874 struct sctp_association *new_asoc) 1875 { 1876 struct sctp_init_chunk *peer_init; 1877 enum sctp_disposition disposition; 1878 struct sctp_ulpevent *ev; 1879 struct sctp_chunk *repl; 1880 struct sctp_chunk *err; 1881 1882 /* new_asoc is a brand-new association, so these are not yet 1883 * side effects--it is safe to run them here. 1884 */ 1885 peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1); 1886 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1887 GFP_ATOMIC)) 1888 goto nomem; 1889 1890 if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC)) 1891 goto nomem; 1892 1893 if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) 1894 return SCTP_DISPOSITION_DISCARD; 1895 1896 /* Make sure no new addresses are being added during the 1897 * restart. Though this is a pretty complicated attack 1898 * since you'd have to get inside the cookie. 1899 */ 1900 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) 1901 return SCTP_DISPOSITION_CONSUME; 1902 1903 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes 1904 * the peer has restarted (Action A), it MUST NOT setup a new 1905 * association but instead resend the SHUTDOWN ACK and send an ERROR 1906 * chunk with a "Cookie Received while Shutting Down" error cause to 1907 * its peer. 1908 */ 1909 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { 1910 disposition = __sctp_sf_do_9_2_reshutack(net, ep, asoc, 1911 SCTP_ST_CHUNK(chunk->chunk_hdr->type), 1912 chunk, commands); 1913 if (SCTP_DISPOSITION_NOMEM == disposition) 1914 goto nomem; 1915 1916 err = sctp_make_op_error(asoc, chunk, 1917 SCTP_ERROR_COOKIE_IN_SHUTDOWN, 1918 NULL, 0, 0); 1919 if (err) 1920 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1921 SCTP_CHUNK(err)); 1922 1923 return SCTP_DISPOSITION_CONSUME; 1924 } 1925 1926 /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked 1927 * data. Consider the optional choice of resending of this data. 1928 */ 1929 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 1930 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1931 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); 1932 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 1933 1934 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue 1935 * and ASCONF-ACK cache. 1936 */ 1937 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1938 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 1939 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL()); 1940 1941 /* Update the content of current association. */ 1942 if (sctp_sf_do_assoc_update((struct sctp_association *)asoc, new_asoc, commands)) 1943 goto nomem; 1944 1945 repl = sctp_make_cookie_ack(asoc, chunk); 1946 if (!repl) 1947 goto nomem; 1948 1949 /* Report association restart to upper layer. */ 1950 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, 1951 asoc->c.sinit_num_ostreams, 1952 asoc->c.sinit_max_instreams, 1953 NULL, GFP_ATOMIC); 1954 if (!ev) 1955 goto nomem_ev; 1956 1957 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1958 if ((sctp_state(asoc, SHUTDOWN_PENDING) || 1959 sctp_state(asoc, SHUTDOWN_SENT)) && 1960 (sctp_sstate(asoc->base.sk, CLOSING) || 1961 sock_flag(asoc->base.sk, SOCK_DEAD))) { 1962 /* If the socket has been closed by user, don't 1963 * transition to ESTABLISHED. Instead trigger SHUTDOWN 1964 * bundled with COOKIE_ACK. 1965 */ 1966 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1967 return sctp_sf_do_9_2_start_shutdown(net, ep, asoc, 1968 SCTP_ST_CHUNK(0), repl, 1969 commands); 1970 } else { 1971 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1972 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1973 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1974 } 1975 return SCTP_DISPOSITION_CONSUME; 1976 1977 nomem_ev: 1978 sctp_chunk_free(repl); 1979 nomem: 1980 return SCTP_DISPOSITION_NOMEM; 1981 } 1982 1983 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') 1984 * 1985 * Section 5.2.4 1986 * B) In this case, both sides may be attempting to start an association 1987 * at about the same time but the peer endpoint started its INIT 1988 * after responding to the local endpoint's INIT 1989 */ 1990 /* This case represents an initialization collision. */ 1991 static enum sctp_disposition sctp_sf_do_dupcook_b( 1992 struct net *net, 1993 const struct sctp_endpoint *ep, 1994 const struct sctp_association *asoc, 1995 struct sctp_chunk *chunk, 1996 struct sctp_cmd_seq *commands, 1997 struct sctp_association *new_asoc) 1998 { 1999 struct sctp_init_chunk *peer_init; 2000 struct sctp_chunk *repl; 2001 2002 /* new_asoc is a brand-new association, so these are not yet 2003 * side effects--it is safe to run them here. 2004 */ 2005 peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1); 2006 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 2007 GFP_ATOMIC)) 2008 goto nomem; 2009 2010 if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC)) 2011 goto nomem; 2012 2013 if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) 2014 return SCTP_DISPOSITION_DISCARD; 2015 2016 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2017 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 2018 if (asoc->state < SCTP_STATE_ESTABLISHED) 2019 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 2020 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 2021 2022 /* Update the content of current association. */ 2023 if (sctp_sf_do_assoc_update((struct sctp_association *)asoc, new_asoc, commands)) 2024 goto nomem; 2025 2026 repl = sctp_make_cookie_ack(asoc, chunk); 2027 if (!repl) 2028 goto nomem; 2029 2030 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 2031 2032 /* RFC 2960 5.1 Normal Establishment of an Association 2033 * 2034 * D) IMPLEMENTATION NOTE: An implementation may choose to 2035 * send the Communication Up notification to the SCTP user 2036 * upon reception of a valid COOKIE ECHO chunk. 2037 * 2038 * Sadly, this needs to be implemented as a side-effect, because 2039 * we are not guaranteed to have set the association id of the real 2040 * association and so these notifications need to be delayed until 2041 * the association id is allocated. 2042 */ 2043 2044 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP)); 2045 2046 /* Sockets API Draft Section 5.3.1.6 2047 * When a peer sends a Adaptation Layer Indication parameter , SCTP 2048 * delivers this notification to inform the application that of the 2049 * peers requested adaptation layer. 2050 * 2051 * This also needs to be done as a side effect for the same reason as 2052 * above. 2053 */ 2054 if (asoc->peer.adaptation_ind) 2055 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL()); 2056 2057 if (!asoc->peer.auth_capable) 2058 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_NO_AUTH, SCTP_NULL()); 2059 2060 return SCTP_DISPOSITION_CONSUME; 2061 2062 nomem: 2063 return SCTP_DISPOSITION_NOMEM; 2064 } 2065 2066 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') 2067 * 2068 * Section 5.2.4 2069 * C) In this case, the local endpoint's cookie has arrived late. 2070 * Before it arrived, the local endpoint sent an INIT and received an 2071 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag 2072 * but a new tag of its own. 2073 */ 2074 /* This case represents an initialization collision. */ 2075 static enum sctp_disposition sctp_sf_do_dupcook_c( 2076 struct net *net, 2077 const struct sctp_endpoint *ep, 2078 const struct sctp_association *asoc, 2079 struct sctp_chunk *chunk, 2080 struct sctp_cmd_seq *commands, 2081 struct sctp_association *new_asoc) 2082 { 2083 /* The cookie should be silently discarded. 2084 * The endpoint SHOULD NOT change states and should leave 2085 * any timers running. 2086 */ 2087 return SCTP_DISPOSITION_DISCARD; 2088 } 2089 2090 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') 2091 * 2092 * Section 5.2.4 2093 * 2094 * D) When both local and remote tags match the endpoint should always 2095 * enter the ESTABLISHED state, if it has not already done so. 2096 */ 2097 /* This case represents an initialization collision. */ 2098 static enum sctp_disposition sctp_sf_do_dupcook_d( 2099 struct net *net, 2100 const struct sctp_endpoint *ep, 2101 const struct sctp_association *asoc, 2102 struct sctp_chunk *chunk, 2103 struct sctp_cmd_seq *commands, 2104 struct sctp_association *new_asoc) 2105 { 2106 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL, *auth_ev = NULL; 2107 struct sctp_chunk *repl; 2108 2109 /* Clarification from Implementor's Guide: 2110 * D) When both local and remote tags match the endpoint should 2111 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. 2112 * It should stop any cookie timer that may be running and send 2113 * a COOKIE ACK. 2114 */ 2115 2116 if (!sctp_auth_chunk_verify(net, chunk, asoc)) 2117 return SCTP_DISPOSITION_DISCARD; 2118 2119 /* Don't accidentally move back into established state. */ 2120 if (asoc->state < SCTP_STATE_ESTABLISHED) { 2121 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2122 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2123 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2124 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 2125 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 2126 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, 2127 SCTP_NULL()); 2128 2129 /* RFC 2960 5.1 Normal Establishment of an Association 2130 * 2131 * D) IMPLEMENTATION NOTE: An implementation may choose 2132 * to send the Communication Up notification to the 2133 * SCTP user upon reception of a valid COOKIE 2134 * ECHO chunk. 2135 */ 2136 ev = sctp_ulpevent_make_assoc_change(asoc, 0, 2137 SCTP_COMM_UP, 0, 2138 asoc->c.sinit_num_ostreams, 2139 asoc->c.sinit_max_instreams, 2140 NULL, GFP_ATOMIC); 2141 if (!ev) 2142 goto nomem; 2143 2144 /* Sockets API Draft Section 5.3.1.6 2145 * When a peer sends a Adaptation Layer Indication parameter, 2146 * SCTP delivers this notification to inform the application 2147 * that of the peers requested adaptation layer. 2148 */ 2149 if (asoc->peer.adaptation_ind) { 2150 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc, 2151 GFP_ATOMIC); 2152 if (!ai_ev) 2153 goto nomem; 2154 2155 } 2156 2157 if (!asoc->peer.auth_capable) { 2158 auth_ev = sctp_ulpevent_make_authkey(asoc, 0, 2159 SCTP_AUTH_NO_AUTH, 2160 GFP_ATOMIC); 2161 if (!auth_ev) 2162 goto nomem; 2163 } 2164 } 2165 2166 repl = sctp_make_cookie_ack(asoc, chunk); 2167 if (!repl) 2168 goto nomem; 2169 2170 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 2171 2172 if (ev) 2173 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2174 SCTP_ULPEVENT(ev)); 2175 if (ai_ev) 2176 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2177 SCTP_ULPEVENT(ai_ev)); 2178 if (auth_ev) 2179 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2180 SCTP_ULPEVENT(auth_ev)); 2181 2182 return SCTP_DISPOSITION_CONSUME; 2183 2184 nomem: 2185 if (auth_ev) 2186 sctp_ulpevent_free(auth_ev); 2187 if (ai_ev) 2188 sctp_ulpevent_free(ai_ev); 2189 if (ev) 2190 sctp_ulpevent_free(ev); 2191 return SCTP_DISPOSITION_NOMEM; 2192 } 2193 2194 /* 2195 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying 2196 * chunk was retransmitted and then delayed in the network. 2197 * 2198 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists 2199 * 2200 * Verification Tag: None. Do cookie validation. 2201 * 2202 * Inputs 2203 * (endpoint, asoc, chunk) 2204 * 2205 * Outputs 2206 * (asoc, reply_msg, msg_up, timers, counters) 2207 * 2208 * The return value is the disposition of the chunk. 2209 */ 2210 enum sctp_disposition sctp_sf_do_5_2_4_dupcook( 2211 struct net *net, 2212 const struct sctp_endpoint *ep, 2213 const struct sctp_association *asoc, 2214 const union sctp_subtype type, 2215 void *arg, 2216 struct sctp_cmd_seq *commands) 2217 { 2218 struct sctp_association *new_asoc; 2219 struct sctp_chunk *chunk = arg; 2220 enum sctp_disposition retval; 2221 struct sctp_chunk *err_chk_p; 2222 int error = 0; 2223 char action; 2224 2225 /* Make sure that the chunk has a valid length from the protocol 2226 * perspective. In this case check to make sure we have at least 2227 * enough for the chunk header. Cookie length verification is 2228 * done later. 2229 */ 2230 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) { 2231 if (!sctp_vtag_verify(chunk, asoc)) 2232 asoc = NULL; 2233 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, commands); 2234 } 2235 2236 /* "Decode" the chunk. We have no optional parameters so we 2237 * are in good shape. 2238 */ 2239 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; 2240 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 2241 sizeof(struct sctp_chunkhdr))) 2242 goto nomem; 2243 2244 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie 2245 * of a duplicate COOKIE ECHO match the Verification Tags of the 2246 * current association, consider the State Cookie valid even if 2247 * the lifespan is exceeded. 2248 */ 2249 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 2250 &err_chk_p); 2251 2252 /* FIXME: 2253 * If the re-build failed, what is the proper error path 2254 * from here? 2255 * 2256 * [We should abort the association. --piggy] 2257 */ 2258 if (!new_asoc) { 2259 /* FIXME: Several errors are possible. A bad cookie should 2260 * be silently discarded, but think about logging it too. 2261 */ 2262 switch (error) { 2263 case -SCTP_IERROR_NOMEM: 2264 goto nomem; 2265 2266 case -SCTP_IERROR_STALE_COOKIE: 2267 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 2268 err_chk_p); 2269 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2270 case -SCTP_IERROR_BAD_SIG: 2271 default: 2272 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2273 } 2274 } 2275 2276 /* Set temp so that it won't be added into hashtable */ 2277 new_asoc->temp = 1; 2278 2279 /* Compare the tie_tag in cookie with the verification tag of 2280 * current association. 2281 */ 2282 action = sctp_tietags_compare(new_asoc, asoc); 2283 2284 /* In cases C and E the association doesn't enter the ESTABLISHED 2285 * state, so there is no need to call security_sctp_assoc_request(). 2286 */ 2287 switch (action) { 2288 case 'A': /* Association restart. */ 2289 case 'B': /* Collision case B. */ 2290 case 'D': /* Collision case D. */ 2291 /* Update socket peer label if first association. */ 2292 if (security_sctp_assoc_request((struct sctp_association *)asoc, 2293 chunk->head_skb ?: chunk->skb)) { 2294 sctp_association_free(new_asoc); 2295 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2296 } 2297 break; 2298 } 2299 2300 switch (action) { 2301 case 'A': /* Association restart. */ 2302 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands, 2303 new_asoc); 2304 break; 2305 2306 case 'B': /* Collision case B. */ 2307 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands, 2308 new_asoc); 2309 break; 2310 2311 case 'C': /* Collision case C. */ 2312 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands, 2313 new_asoc); 2314 break; 2315 2316 case 'D': /* Collision case D. */ 2317 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands, 2318 new_asoc); 2319 break; 2320 2321 default: /* Discard packet for all others. */ 2322 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2323 break; 2324 } 2325 2326 /* Delete the temporary new association. */ 2327 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc)); 2328 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 2329 2330 /* Restore association pointer to provide SCTP command interpreter 2331 * with a valid context in case it needs to manipulate 2332 * the queues */ 2333 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, 2334 SCTP_ASOC((struct sctp_association *)asoc)); 2335 2336 return retval; 2337 2338 nomem: 2339 return SCTP_DISPOSITION_NOMEM; 2340 } 2341 2342 /* 2343 * Process an ABORT. (SHUTDOWN-PENDING state) 2344 * 2345 * See sctp_sf_do_9_1_abort(). 2346 */ 2347 enum sctp_disposition sctp_sf_shutdown_pending_abort( 2348 struct net *net, 2349 const struct sctp_endpoint *ep, 2350 const struct sctp_association *asoc, 2351 const union sctp_subtype type, 2352 void *arg, 2353 struct sctp_cmd_seq *commands) 2354 { 2355 struct sctp_chunk *chunk = arg; 2356 2357 if (!sctp_vtag_verify_either(chunk, asoc)) 2358 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2359 2360 /* Make sure that the ABORT chunk has a valid length. 2361 * Since this is an ABORT chunk, we have to discard it 2362 * because of the following text: 2363 * RFC 2960, Section 3.3.7 2364 * If an endpoint receives an ABORT with a format error or for an 2365 * association that doesn't exist, it MUST silently discard it. 2366 * Because the length is "invalid", we can't really discard just 2367 * as we do not know its true length. So, to be safe, discard the 2368 * packet. 2369 */ 2370 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2371 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2372 2373 /* ADD-IP: Special case for ABORT chunks 2374 * F4) One special consideration is that ABORT Chunks arriving 2375 * destined to the IP address being deleted MUST be 2376 * ignored (see Section 5.3.1 for further details). 2377 */ 2378 if (SCTP_ADDR_DEL == 2379 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2380 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2381 2382 if (!sctp_err_chunk_valid(chunk)) 2383 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2384 2385 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2386 } 2387 2388 /* 2389 * Process an ABORT. (SHUTDOWN-SENT state) 2390 * 2391 * See sctp_sf_do_9_1_abort(). 2392 */ 2393 enum sctp_disposition sctp_sf_shutdown_sent_abort( 2394 struct net *net, 2395 const struct sctp_endpoint *ep, 2396 const struct sctp_association *asoc, 2397 const union sctp_subtype type, 2398 void *arg, 2399 struct sctp_cmd_seq *commands) 2400 { 2401 struct sctp_chunk *chunk = arg; 2402 2403 if (!sctp_vtag_verify_either(chunk, asoc)) 2404 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2405 2406 /* Make sure that the ABORT chunk has a valid length. 2407 * Since this is an ABORT chunk, we have to discard it 2408 * because of the following text: 2409 * RFC 2960, Section 3.3.7 2410 * If an endpoint receives an ABORT with a format error or for an 2411 * association that doesn't exist, it MUST silently discard it. 2412 * Because the length is "invalid", we can't really discard just 2413 * as we do not know its true length. So, to be safe, discard the 2414 * packet. 2415 */ 2416 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2417 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2418 2419 /* ADD-IP: Special case for ABORT chunks 2420 * F4) One special consideration is that ABORT Chunks arriving 2421 * destined to the IP address being deleted MUST be 2422 * ignored (see Section 5.3.1 for further details). 2423 */ 2424 if (SCTP_ADDR_DEL == 2425 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2426 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2427 2428 if (!sctp_err_chunk_valid(chunk)) 2429 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2430 2431 /* Stop the T2-shutdown timer. */ 2432 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2433 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2434 2435 /* Stop the T5-shutdown guard timer. */ 2436 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2437 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2438 2439 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2440 } 2441 2442 /* 2443 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2444 * 2445 * See sctp_sf_do_9_1_abort(). 2446 */ 2447 enum sctp_disposition sctp_sf_shutdown_ack_sent_abort( 2448 struct net *net, 2449 const struct sctp_endpoint *ep, 2450 const struct sctp_association *asoc, 2451 const union sctp_subtype type, 2452 void *arg, 2453 struct sctp_cmd_seq *commands) 2454 { 2455 /* The same T2 timer, so we should be able to use 2456 * common function with the SHUTDOWN-SENT state. 2457 */ 2458 return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands); 2459 } 2460 2461 /* 2462 * Handle an Error received in COOKIE_ECHOED state. 2463 * 2464 * Only handle the error type of stale COOKIE Error, the other errors will 2465 * be ignored. 2466 * 2467 * Inputs 2468 * (endpoint, asoc, chunk) 2469 * 2470 * Outputs 2471 * (asoc, reply_msg, msg_up, timers, counters) 2472 * 2473 * The return value is the disposition of the chunk. 2474 */ 2475 enum sctp_disposition sctp_sf_cookie_echoed_err( 2476 struct net *net, 2477 const struct sctp_endpoint *ep, 2478 const struct sctp_association *asoc, 2479 const union sctp_subtype type, 2480 void *arg, 2481 struct sctp_cmd_seq *commands) 2482 { 2483 struct sctp_chunk *chunk = arg; 2484 struct sctp_errhdr *err; 2485 2486 if (!sctp_vtag_verify(chunk, asoc)) 2487 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2488 2489 /* Make sure that the ERROR chunk has a valid length. 2490 * The parameter walking depends on this as well. 2491 */ 2492 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk))) 2493 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2494 commands); 2495 2496 /* Process the error here */ 2497 /* FUTURE FIXME: When PR-SCTP related and other optional 2498 * parms are emitted, this will have to change to handle multiple 2499 * errors. 2500 */ 2501 sctp_walk_errors(err, chunk->chunk_hdr) { 2502 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2503 return sctp_sf_do_5_2_6_stale(net, ep, asoc, type, 2504 arg, commands); 2505 } 2506 2507 /* It is possible to have malformed error causes, and that 2508 * will cause us to end the walk early. However, since 2509 * we are discarding the packet, there should be no adverse 2510 * affects. 2511 */ 2512 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2513 } 2514 2515 /* 2516 * Handle a Stale COOKIE Error 2517 * 2518 * Section: 5.2.6 Handle Stale COOKIE Error 2519 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2520 * one of the following three alternatives. 2521 * ... 2522 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2523 * Preservative parameter requesting an extension to the lifetime of 2524 * the State Cookie. When calculating the time extension, an 2525 * implementation SHOULD use the RTT information measured based on the 2526 * previous COOKIE ECHO / ERROR exchange, and should add no more 2527 * than 1 second beyond the measured RTT, due to long State Cookie 2528 * lifetimes making the endpoint more subject to a replay attack. 2529 * 2530 * Verification Tag: Not explicit, but safe to ignore. 2531 * 2532 * Inputs 2533 * (endpoint, asoc, chunk) 2534 * 2535 * Outputs 2536 * (asoc, reply_msg, msg_up, timers, counters) 2537 * 2538 * The return value is the disposition of the chunk. 2539 */ 2540 static enum sctp_disposition sctp_sf_do_5_2_6_stale( 2541 struct net *net, 2542 const struct sctp_endpoint *ep, 2543 const struct sctp_association *asoc, 2544 const union sctp_subtype type, 2545 void *arg, 2546 struct sctp_cmd_seq *commands) 2547 { 2548 int attempts = asoc->init_err_counter + 1; 2549 struct sctp_chunk *chunk = arg, *reply; 2550 struct sctp_cookie_preserve_param bht; 2551 struct sctp_bind_addr *bp; 2552 struct sctp_errhdr *err; 2553 u32 stale; 2554 2555 if (attempts > asoc->max_init_attempts) { 2556 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 2557 SCTP_ERROR(ETIMEDOUT)); 2558 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2559 SCTP_PERR(SCTP_ERROR_STALE_COOKIE)); 2560 return SCTP_DISPOSITION_DELETE_TCB; 2561 } 2562 2563 err = (struct sctp_errhdr *)(chunk->skb->data); 2564 2565 /* When calculating the time extension, an implementation 2566 * SHOULD use the RTT information measured based on the 2567 * previous COOKIE ECHO / ERROR exchange, and should add no 2568 * more than 1 second beyond the measured RTT, due to long 2569 * State Cookie lifetimes making the endpoint more subject to 2570 * a replay attack. 2571 * Measure of Staleness's unit is usec. (1/1000000 sec) 2572 * Suggested Cookie Life-span Increment's unit is msec. 2573 * (1/1000 sec) 2574 * In general, if you use the suggested cookie life, the value 2575 * found in the field of measure of staleness should be doubled 2576 * to give ample time to retransmit the new cookie and thus 2577 * yield a higher probability of success on the reattempt. 2578 */ 2579 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err))); 2580 stale = (stale * 2) / 1000; 2581 2582 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2583 bht.param_hdr.length = htons(sizeof(bht)); 2584 bht.lifespan_increment = htonl(stale); 2585 2586 /* Build that new INIT chunk. */ 2587 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2588 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2589 if (!reply) 2590 goto nomem; 2591 2592 sctp_addto_chunk(reply, sizeof(bht), &bht); 2593 2594 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2595 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2596 2597 /* Stop pending T3-rtx and heartbeat timers */ 2598 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2599 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2600 2601 /* Delete non-primary peer ip addresses since we are transitioning 2602 * back to the COOKIE-WAIT state 2603 */ 2604 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2605 2606 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 2607 2608 /* Cast away the const modifier, as we want to just 2609 * rerun it through as a sideffect. 2610 */ 2611 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2612 2613 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2614 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2615 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2616 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2617 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2618 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2619 2620 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2621 2622 return SCTP_DISPOSITION_CONSUME; 2623 2624 nomem: 2625 return SCTP_DISPOSITION_NOMEM; 2626 } 2627 2628 /* 2629 * Process an ABORT. 2630 * 2631 * Section: 9.1 2632 * After checking the Verification Tag, the receiving endpoint shall 2633 * remove the association from its record, and shall report the 2634 * termination to its upper layer. 2635 * 2636 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2637 * B) Rules for packet carrying ABORT: 2638 * 2639 * - The endpoint shall always fill in the Verification Tag field of the 2640 * outbound packet with the destination endpoint's tag value if it 2641 * is known. 2642 * 2643 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2644 * MUST follow the procedure described in Section 8.4. 2645 * 2646 * - The receiver MUST accept the packet if the Verification Tag 2647 * matches either its own tag, OR the tag of its peer. Otherwise, the 2648 * receiver MUST silently discard the packet and take no further 2649 * action. 2650 * 2651 * Inputs 2652 * (endpoint, asoc, chunk) 2653 * 2654 * Outputs 2655 * (asoc, reply_msg, msg_up, timers, counters) 2656 * 2657 * The return value is the disposition of the chunk. 2658 */ 2659 enum sctp_disposition sctp_sf_do_9_1_abort( 2660 struct net *net, 2661 const struct sctp_endpoint *ep, 2662 const struct sctp_association *asoc, 2663 const union sctp_subtype type, 2664 void *arg, 2665 struct sctp_cmd_seq *commands) 2666 { 2667 struct sctp_chunk *chunk = arg; 2668 2669 if (!sctp_vtag_verify_either(chunk, asoc)) 2670 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2671 2672 /* Make sure that the ABORT chunk has a valid length. 2673 * Since this is an ABORT chunk, we have to discard it 2674 * because of the following text: 2675 * RFC 2960, Section 3.3.7 2676 * If an endpoint receives an ABORT with a format error or for an 2677 * association that doesn't exist, it MUST silently discard it. 2678 * Because the length is "invalid", we can't really discard just 2679 * as we do not know its true length. So, to be safe, discard the 2680 * packet. 2681 */ 2682 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2683 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2684 2685 /* ADD-IP: Special case for ABORT chunks 2686 * F4) One special consideration is that ABORT Chunks arriving 2687 * destined to the IP address being deleted MUST be 2688 * ignored (see Section 5.3.1 for further details). 2689 */ 2690 if (SCTP_ADDR_DEL == 2691 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2692 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2693 2694 if (!sctp_err_chunk_valid(chunk)) 2695 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2696 2697 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2698 } 2699 2700 static enum sctp_disposition __sctp_sf_do_9_1_abort( 2701 struct net *net, 2702 const struct sctp_endpoint *ep, 2703 const struct sctp_association *asoc, 2704 const union sctp_subtype type, 2705 void *arg, 2706 struct sctp_cmd_seq *commands) 2707 { 2708 __be16 error = SCTP_ERROR_NO_ERROR; 2709 struct sctp_chunk *chunk = arg; 2710 unsigned int len; 2711 2712 /* See if we have an error cause code in the chunk. */ 2713 len = ntohs(chunk->chunk_hdr->length); 2714 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2715 error = ((struct sctp_errhdr *)chunk->skb->data)->cause; 2716 2717 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET)); 2718 /* ASSOC_FAILED will DELETE_TCB. */ 2719 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error)); 2720 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2721 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 2722 2723 return SCTP_DISPOSITION_ABORT; 2724 } 2725 2726 /* 2727 * Process an ABORT. (COOKIE-WAIT state) 2728 * 2729 * See sctp_sf_do_9_1_abort() above. 2730 */ 2731 enum sctp_disposition sctp_sf_cookie_wait_abort( 2732 struct net *net, 2733 const struct sctp_endpoint *ep, 2734 const struct sctp_association *asoc, 2735 const union sctp_subtype type, 2736 void *arg, 2737 struct sctp_cmd_seq *commands) 2738 { 2739 __be16 error = SCTP_ERROR_NO_ERROR; 2740 struct sctp_chunk *chunk = arg; 2741 unsigned int len; 2742 2743 if (!sctp_vtag_verify_either(chunk, asoc)) 2744 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2745 2746 /* Make sure that the ABORT chunk has a valid length. 2747 * Since this is an ABORT chunk, we have to discard it 2748 * because of the following text: 2749 * RFC 2960, Section 3.3.7 2750 * If an endpoint receives an ABORT with a format error or for an 2751 * association that doesn't exist, it MUST silently discard it. 2752 * Because the length is "invalid", we can't really discard just 2753 * as we do not know its true length. So, to be safe, discard the 2754 * packet. 2755 */ 2756 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2757 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2758 2759 /* See if we have an error cause code in the chunk. */ 2760 len = ntohs(chunk->chunk_hdr->length); 2761 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2762 error = ((struct sctp_errhdr *)chunk->skb->data)->cause; 2763 2764 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc, 2765 chunk->transport); 2766 } 2767 2768 /* 2769 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2770 */ 2771 enum sctp_disposition sctp_sf_cookie_wait_icmp_abort( 2772 struct net *net, 2773 const struct sctp_endpoint *ep, 2774 const struct sctp_association *asoc, 2775 const union sctp_subtype type, 2776 void *arg, 2777 struct sctp_cmd_seq *commands) 2778 { 2779 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR, 2780 ENOPROTOOPT, asoc, 2781 (struct sctp_transport *)arg); 2782 } 2783 2784 /* 2785 * Process an ABORT. (COOKIE-ECHOED state) 2786 */ 2787 enum sctp_disposition sctp_sf_cookie_echoed_abort( 2788 struct net *net, 2789 const struct sctp_endpoint *ep, 2790 const struct sctp_association *asoc, 2791 const union sctp_subtype type, 2792 void *arg, 2793 struct sctp_cmd_seq *commands) 2794 { 2795 /* There is a single T1 timer, so we should be able to use 2796 * common function with the COOKIE-WAIT state. 2797 */ 2798 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands); 2799 } 2800 2801 /* 2802 * Stop T1 timer and abort association with "INIT failed". 2803 * 2804 * This is common code called by several sctp_sf_*_abort() functions above. 2805 */ 2806 static enum sctp_disposition sctp_stop_t1_and_abort( 2807 struct net *net, 2808 struct sctp_cmd_seq *commands, 2809 __be16 error, int sk_err, 2810 const struct sctp_association *asoc, 2811 struct sctp_transport *transport) 2812 { 2813 pr_debug("%s: ABORT received (INIT)\n", __func__); 2814 2815 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2816 SCTP_STATE(SCTP_STATE_CLOSED)); 2817 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2818 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2819 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2820 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err)); 2821 /* CMD_INIT_FAILED will DELETE_TCB. */ 2822 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2823 SCTP_PERR(error)); 2824 2825 return SCTP_DISPOSITION_ABORT; 2826 } 2827 2828 /* 2829 * sctp_sf_do_9_2_shut 2830 * 2831 * Section: 9.2 2832 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2833 * - enter the SHUTDOWN-RECEIVED state, 2834 * 2835 * - stop accepting new data from its SCTP user 2836 * 2837 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2838 * that all its outstanding DATA chunks have been received by the 2839 * SHUTDOWN sender. 2840 * 2841 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2842 * send a SHUTDOWN in response to a ULP request. And should discard 2843 * subsequent SHUTDOWN chunks. 2844 * 2845 * If there are still outstanding DATA chunks left, the SHUTDOWN 2846 * receiver shall continue to follow normal data transmission 2847 * procedures defined in Section 6 until all outstanding DATA chunks 2848 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2849 * new data from its SCTP user. 2850 * 2851 * Verification Tag: 8.5 Verification Tag [Normal verification] 2852 * 2853 * Inputs 2854 * (endpoint, asoc, chunk) 2855 * 2856 * Outputs 2857 * (asoc, reply_msg, msg_up, timers, counters) 2858 * 2859 * The return value is the disposition of the chunk. 2860 */ 2861 enum sctp_disposition sctp_sf_do_9_2_shutdown( 2862 struct net *net, 2863 const struct sctp_endpoint *ep, 2864 const struct sctp_association *asoc, 2865 const union sctp_subtype type, 2866 void *arg, 2867 struct sctp_cmd_seq *commands) 2868 { 2869 enum sctp_disposition disposition; 2870 struct sctp_chunk *chunk = arg; 2871 struct sctp_shutdownhdr *sdh; 2872 struct sctp_ulpevent *ev; 2873 __u32 ctsn; 2874 2875 if (!sctp_vtag_verify(chunk, asoc)) 2876 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2877 2878 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2879 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk))) 2880 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2881 commands); 2882 2883 /* Convert the elaborate header. */ 2884 sdh = (struct sctp_shutdownhdr *)chunk->skb->data; 2885 skb_pull(chunk->skb, sizeof(*sdh)); 2886 chunk->subh.shutdown_hdr = sdh; 2887 ctsn = ntohl(sdh->cum_tsn_ack); 2888 2889 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2890 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2891 asoc->ctsn_ack_point); 2892 2893 return SCTP_DISPOSITION_DISCARD; 2894 } 2895 2896 /* If Cumulative TSN Ack beyond the max tsn currently 2897 * send, terminating the association and respond to the 2898 * sender with an ABORT. 2899 */ 2900 if (!TSN_lt(ctsn, asoc->next_tsn)) 2901 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2902 2903 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2904 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2905 * inform the application that it should cease sending data. 2906 */ 2907 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2908 if (!ev) { 2909 disposition = SCTP_DISPOSITION_NOMEM; 2910 goto out; 2911 } 2912 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2913 2914 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2915 * - enter the SHUTDOWN-RECEIVED state, 2916 * - stop accepting new data from its SCTP user 2917 * 2918 * [This is implicit in the new state.] 2919 */ 2920 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2921 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2922 disposition = SCTP_DISPOSITION_CONSUME; 2923 2924 if (sctp_outq_is_empty(&asoc->outqueue)) { 2925 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type, 2926 arg, commands); 2927 } 2928 2929 if (SCTP_DISPOSITION_NOMEM == disposition) 2930 goto out; 2931 2932 /* - verify, by checking the Cumulative TSN Ack field of the 2933 * chunk, that all its outstanding DATA chunks have been 2934 * received by the SHUTDOWN sender. 2935 */ 2936 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2937 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2938 2939 out: 2940 return disposition; 2941 } 2942 2943 /* 2944 * sctp_sf_do_9_2_shut_ctsn 2945 * 2946 * Once an endpoint has reached the SHUTDOWN-RECEIVED state, 2947 * it MUST NOT send a SHUTDOWN in response to a ULP request. 2948 * The Cumulative TSN Ack of the received SHUTDOWN chunk 2949 * MUST be processed. 2950 */ 2951 enum sctp_disposition sctp_sf_do_9_2_shut_ctsn( 2952 struct net *net, 2953 const struct sctp_endpoint *ep, 2954 const struct sctp_association *asoc, 2955 const union sctp_subtype type, 2956 void *arg, 2957 struct sctp_cmd_seq *commands) 2958 { 2959 struct sctp_chunk *chunk = arg; 2960 struct sctp_shutdownhdr *sdh; 2961 __u32 ctsn; 2962 2963 if (!sctp_vtag_verify(chunk, asoc)) 2964 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2965 2966 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2967 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk))) 2968 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2969 commands); 2970 2971 sdh = (struct sctp_shutdownhdr *)chunk->skb->data; 2972 ctsn = ntohl(sdh->cum_tsn_ack); 2973 2974 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2975 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2976 asoc->ctsn_ack_point); 2977 2978 return SCTP_DISPOSITION_DISCARD; 2979 } 2980 2981 /* If Cumulative TSN Ack beyond the max tsn currently 2982 * send, terminating the association and respond to the 2983 * sender with an ABORT. 2984 */ 2985 if (!TSN_lt(ctsn, asoc->next_tsn)) 2986 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2987 2988 /* verify, by checking the Cumulative TSN Ack field of the 2989 * chunk, that all its outstanding DATA chunks have been 2990 * received by the SHUTDOWN sender. 2991 */ 2992 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2993 SCTP_BE32(sdh->cum_tsn_ack)); 2994 2995 return SCTP_DISPOSITION_CONSUME; 2996 } 2997 2998 /* RFC 2960 9.2 2999 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 3000 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 3001 * transport addresses (either in the IP addresses or in the INIT chunk) 3002 * that belong to this association, it should discard the INIT chunk and 3003 * retransmit the SHUTDOWN ACK chunk. 3004 */ 3005 static enum sctp_disposition 3006 __sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep, 3007 const struct sctp_association *asoc, 3008 const union sctp_subtype type, void *arg, 3009 struct sctp_cmd_seq *commands) 3010 { 3011 struct sctp_chunk *chunk = arg; 3012 struct sctp_chunk *reply; 3013 3014 /* Make sure that the chunk has a valid length */ 3015 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3016 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3017 commands); 3018 3019 /* Since we are not going to really process this INIT, there 3020 * is no point in verifying chunk boundaries. Just generate 3021 * the SHUTDOWN ACK. 3022 */ 3023 reply = sctp_make_shutdown_ack(asoc, chunk); 3024 if (NULL == reply) 3025 goto nomem; 3026 3027 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 3028 * the T2-SHUTDOWN timer. 3029 */ 3030 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 3031 3032 /* and restart the T2-shutdown timer. */ 3033 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3034 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3035 3036 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3037 3038 return SCTP_DISPOSITION_CONSUME; 3039 nomem: 3040 return SCTP_DISPOSITION_NOMEM; 3041 } 3042 3043 enum sctp_disposition 3044 sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep, 3045 const struct sctp_association *asoc, 3046 const union sctp_subtype type, void *arg, 3047 struct sctp_cmd_seq *commands) 3048 { 3049 struct sctp_chunk *chunk = arg; 3050 3051 if (!chunk->singleton) 3052 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3053 3054 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk))) 3055 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3056 3057 if (chunk->sctp_hdr->vtag != 0) 3058 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 3059 3060 return __sctp_sf_do_9_2_reshutack(net, ep, asoc, type, arg, commands); 3061 } 3062 3063 /* 3064 * sctp_sf_do_ecn_cwr 3065 * 3066 * Section: Appendix A: Explicit Congestion Notification 3067 * 3068 * CWR: 3069 * 3070 * RFC 2481 details a specific bit for a sender to send in the header of 3071 * its next outbound TCP segment to indicate to its peer that it has 3072 * reduced its congestion window. This is termed the CWR bit. For 3073 * SCTP the same indication is made by including the CWR chunk. 3074 * This chunk contains one data element, i.e. the TSN number that 3075 * was sent in the ECNE chunk. This element represents the lowest 3076 * TSN number in the datagram that was originally marked with the 3077 * CE bit. 3078 * 3079 * Verification Tag: 8.5 Verification Tag [Normal verification] 3080 * Inputs 3081 * (endpoint, asoc, chunk) 3082 * 3083 * Outputs 3084 * (asoc, reply_msg, msg_up, timers, counters) 3085 * 3086 * The return value is the disposition of the chunk. 3087 */ 3088 enum sctp_disposition sctp_sf_do_ecn_cwr(struct net *net, 3089 const struct sctp_endpoint *ep, 3090 const struct sctp_association *asoc, 3091 const union sctp_subtype type, 3092 void *arg, 3093 struct sctp_cmd_seq *commands) 3094 { 3095 struct sctp_chunk *chunk = arg; 3096 struct sctp_cwrhdr *cwr; 3097 u32 lowest_tsn; 3098 3099 if (!sctp_vtag_verify(chunk, asoc)) 3100 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3101 3102 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk))) 3103 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3104 commands); 3105 3106 cwr = (struct sctp_cwrhdr *)chunk->skb->data; 3107 skb_pull(chunk->skb, sizeof(*cwr)); 3108 3109 lowest_tsn = ntohl(cwr->lowest_tsn); 3110 3111 /* Does this CWR ack the last sent congestion notification? */ 3112 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) { 3113 /* Stop sending ECNE. */ 3114 sctp_add_cmd_sf(commands, 3115 SCTP_CMD_ECN_CWR, 3116 SCTP_U32(lowest_tsn)); 3117 } 3118 return SCTP_DISPOSITION_CONSUME; 3119 } 3120 3121 /* 3122 * sctp_sf_do_ecne 3123 * 3124 * Section: Appendix A: Explicit Congestion Notification 3125 * 3126 * ECN-Echo 3127 * 3128 * RFC 2481 details a specific bit for a receiver to send back in its 3129 * TCP acknowledgements to notify the sender of the Congestion 3130 * Experienced (CE) bit having arrived from the network. For SCTP this 3131 * same indication is made by including the ECNE chunk. This chunk 3132 * contains one data element, i.e. the lowest TSN associated with the IP 3133 * datagram marked with the CE bit..... 3134 * 3135 * Verification Tag: 8.5 Verification Tag [Normal verification] 3136 * Inputs 3137 * (endpoint, asoc, chunk) 3138 * 3139 * Outputs 3140 * (asoc, reply_msg, msg_up, timers, counters) 3141 * 3142 * The return value is the disposition of the chunk. 3143 */ 3144 enum sctp_disposition sctp_sf_do_ecne(struct net *net, 3145 const struct sctp_endpoint *ep, 3146 const struct sctp_association *asoc, 3147 const union sctp_subtype type, 3148 void *arg, struct sctp_cmd_seq *commands) 3149 { 3150 struct sctp_chunk *chunk = arg; 3151 struct sctp_ecnehdr *ecne; 3152 3153 if (!sctp_vtag_verify(chunk, asoc)) 3154 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3155 3156 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk))) 3157 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3158 commands); 3159 3160 ecne = (struct sctp_ecnehdr *)chunk->skb->data; 3161 skb_pull(chunk->skb, sizeof(*ecne)); 3162 3163 /* If this is a newer ECNE than the last CWR packet we sent out */ 3164 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 3165 SCTP_U32(ntohl(ecne->lowest_tsn))); 3166 3167 return SCTP_DISPOSITION_CONSUME; 3168 } 3169 3170 /* 3171 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 3172 * 3173 * The SCTP endpoint MUST always acknowledge the reception of each valid 3174 * DATA chunk. 3175 * 3176 * The guidelines on delayed acknowledgement algorithm specified in 3177 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 3178 * acknowledgement SHOULD be generated for at least every second packet 3179 * (not every second DATA chunk) received, and SHOULD be generated within 3180 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 3181 * situations it may be beneficial for an SCTP transmitter to be more 3182 * conservative than the algorithms detailed in this document allow. 3183 * However, an SCTP transmitter MUST NOT be more aggressive than the 3184 * following algorithms allow. 3185 * 3186 * A SCTP receiver MUST NOT generate more than one SACK for every 3187 * incoming packet, other than to update the offered window as the 3188 * receiving application consumes new data. 3189 * 3190 * Verification Tag: 8.5 Verification Tag [Normal verification] 3191 * 3192 * Inputs 3193 * (endpoint, asoc, chunk) 3194 * 3195 * Outputs 3196 * (asoc, reply_msg, msg_up, timers, counters) 3197 * 3198 * The return value is the disposition of the chunk. 3199 */ 3200 enum sctp_disposition sctp_sf_eat_data_6_2(struct net *net, 3201 const struct sctp_endpoint *ep, 3202 const struct sctp_association *asoc, 3203 const union sctp_subtype type, 3204 void *arg, 3205 struct sctp_cmd_seq *commands) 3206 { 3207 union sctp_arg force = SCTP_NOFORCE(); 3208 struct sctp_chunk *chunk = arg; 3209 int error; 3210 3211 if (!sctp_vtag_verify(chunk, asoc)) { 3212 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3213 SCTP_NULL()); 3214 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3215 } 3216 3217 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream))) 3218 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3219 commands); 3220 3221 error = sctp_eat_data(asoc, chunk, commands); 3222 switch (error) { 3223 case SCTP_IERROR_NO_ERROR: 3224 break; 3225 case SCTP_IERROR_HIGH_TSN: 3226 case SCTP_IERROR_BAD_STREAM: 3227 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3228 goto discard_noforce; 3229 case SCTP_IERROR_DUP_TSN: 3230 case SCTP_IERROR_IGNORE_TSN: 3231 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3232 goto discard_force; 3233 case SCTP_IERROR_NO_DATA: 3234 return SCTP_DISPOSITION_ABORT; 3235 case SCTP_IERROR_PROTO_VIOLATION: 3236 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3237 (u8 *)chunk->subh.data_hdr, 3238 sctp_datahdr_len(&asoc->stream)); 3239 default: 3240 BUG(); 3241 } 3242 3243 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM) 3244 force = SCTP_FORCE(); 3245 3246 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 3247 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3248 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3249 } 3250 3251 /* If this is the last chunk in a packet, we need to count it 3252 * toward sack generation. Note that we need to SACK every 3253 * OTHER packet containing data chunks, EVEN IF WE DISCARD 3254 * THEM. We elect to NOT generate SACK's if the chunk fails 3255 * the verification tag test. 3256 * 3257 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3258 * 3259 * The SCTP endpoint MUST always acknowledge the reception of 3260 * each valid DATA chunk. 3261 * 3262 * The guidelines on delayed acknowledgement algorithm 3263 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 3264 * Specifically, an acknowledgement SHOULD be generated for at 3265 * least every second packet (not every second DATA chunk) 3266 * received, and SHOULD be generated within 200 ms of the 3267 * arrival of any unacknowledged DATA chunk. In some 3268 * situations it may be beneficial for an SCTP transmitter to 3269 * be more conservative than the algorithms detailed in this 3270 * document allow. However, an SCTP transmitter MUST NOT be 3271 * more aggressive than the following algorithms allow. 3272 */ 3273 if (chunk->end_of_packet) 3274 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3275 3276 return SCTP_DISPOSITION_CONSUME; 3277 3278 discard_force: 3279 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3280 * 3281 * When a packet arrives with duplicate DATA chunk(s) and with 3282 * no new DATA chunk(s), the endpoint MUST immediately send a 3283 * SACK with no delay. If a packet arrives with duplicate 3284 * DATA chunk(s) bundled with new DATA chunks, the endpoint 3285 * MAY immediately send a SACK. Normally receipt of duplicate 3286 * DATA chunks will occur when the original SACK chunk was lost 3287 * and the peer's RTO has expired. The duplicate TSN number(s) 3288 * SHOULD be reported in the SACK as duplicate. 3289 */ 3290 /* In our case, we split the MAY SACK advice up whether or not 3291 * the last chunk is a duplicate.' 3292 */ 3293 if (chunk->end_of_packet) 3294 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3295 return SCTP_DISPOSITION_DISCARD; 3296 3297 discard_noforce: 3298 if (chunk->end_of_packet) 3299 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3300 3301 return SCTP_DISPOSITION_DISCARD; 3302 } 3303 3304 /* 3305 * sctp_sf_eat_data_fast_4_4 3306 * 3307 * Section: 4 (4) 3308 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 3309 * DATA chunks without delay. 3310 * 3311 * Verification Tag: 8.5 Verification Tag [Normal verification] 3312 * Inputs 3313 * (endpoint, asoc, chunk) 3314 * 3315 * Outputs 3316 * (asoc, reply_msg, msg_up, timers, counters) 3317 * 3318 * The return value is the disposition of the chunk. 3319 */ 3320 enum sctp_disposition sctp_sf_eat_data_fast_4_4( 3321 struct net *net, 3322 const struct sctp_endpoint *ep, 3323 const struct sctp_association *asoc, 3324 const union sctp_subtype type, 3325 void *arg, 3326 struct sctp_cmd_seq *commands) 3327 { 3328 struct sctp_chunk *chunk = arg; 3329 int error; 3330 3331 if (!sctp_vtag_verify(chunk, asoc)) { 3332 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3333 SCTP_NULL()); 3334 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3335 } 3336 3337 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream))) 3338 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3339 commands); 3340 3341 error = sctp_eat_data(asoc, chunk, commands); 3342 switch (error) { 3343 case SCTP_IERROR_NO_ERROR: 3344 case SCTP_IERROR_HIGH_TSN: 3345 case SCTP_IERROR_DUP_TSN: 3346 case SCTP_IERROR_IGNORE_TSN: 3347 case SCTP_IERROR_BAD_STREAM: 3348 break; 3349 case SCTP_IERROR_NO_DATA: 3350 return SCTP_DISPOSITION_ABORT; 3351 case SCTP_IERROR_PROTO_VIOLATION: 3352 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3353 (u8 *)chunk->subh.data_hdr, 3354 sctp_datahdr_len(&asoc->stream)); 3355 default: 3356 BUG(); 3357 } 3358 3359 /* Go a head and force a SACK, since we are shutting down. */ 3360 3361 /* Implementor's Guide. 3362 * 3363 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3364 * respond to each received packet containing one or more DATA chunk(s) 3365 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3366 */ 3367 if (chunk->end_of_packet) { 3368 /* We must delay the chunk creation since the cumulative 3369 * TSN has not been updated yet. 3370 */ 3371 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3372 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3373 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3374 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3375 } 3376 3377 return SCTP_DISPOSITION_CONSUME; 3378 } 3379 3380 /* 3381 * Section: 6.2 Processing a Received SACK 3382 * D) Any time a SACK arrives, the endpoint performs the following: 3383 * 3384 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 3385 * then drop the SACK. Since Cumulative TSN Ack is monotonically 3386 * increasing, a SACK whose Cumulative TSN Ack is less than the 3387 * Cumulative TSN Ack Point indicates an out-of-order SACK. 3388 * 3389 * ii) Set rwnd equal to the newly received a_rwnd minus the number 3390 * of bytes still outstanding after processing the Cumulative TSN Ack 3391 * and the Gap Ack Blocks. 3392 * 3393 * iii) If the SACK is missing a TSN that was previously 3394 * acknowledged via a Gap Ack Block (e.g., the data receiver 3395 * reneged on the data), then mark the corresponding DATA chunk 3396 * as available for retransmit: Mark it as missing for fast 3397 * retransmit as described in Section 7.2.4 and if no retransmit 3398 * timer is running for the destination address to which the DATA 3399 * chunk was originally transmitted, then T3-rtx is started for 3400 * that destination address. 3401 * 3402 * Verification Tag: 8.5 Verification Tag [Normal verification] 3403 * 3404 * Inputs 3405 * (endpoint, asoc, chunk) 3406 * 3407 * Outputs 3408 * (asoc, reply_msg, msg_up, timers, counters) 3409 * 3410 * The return value is the disposition of the chunk. 3411 */ 3412 enum sctp_disposition sctp_sf_eat_sack_6_2(struct net *net, 3413 const struct sctp_endpoint *ep, 3414 const struct sctp_association *asoc, 3415 const union sctp_subtype type, 3416 void *arg, 3417 struct sctp_cmd_seq *commands) 3418 { 3419 struct sctp_chunk *chunk = arg; 3420 struct sctp_sackhdr *sackh; 3421 __u32 ctsn; 3422 3423 if (!sctp_vtag_verify(chunk, asoc)) 3424 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3425 3426 /* Make sure that the SACK chunk has a valid length. */ 3427 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_sack_chunk))) 3428 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3429 commands); 3430 3431 /* Pull the SACK chunk from the data buffer */ 3432 sackh = sctp_sm_pull_sack(chunk); 3433 /* Was this a bogus SACK? */ 3434 if (!sackh) 3435 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3436 chunk->subh.sack_hdr = sackh; 3437 ctsn = ntohl(sackh->cum_tsn_ack); 3438 3439 /* If Cumulative TSN Ack beyond the max tsn currently 3440 * send, terminating the association and respond to the 3441 * sender with an ABORT. 3442 */ 3443 if (TSN_lte(asoc->next_tsn, ctsn)) 3444 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 3445 3446 trace_sctp_probe(ep, asoc, chunk); 3447 3448 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 3449 * Ack Point, then drop the SACK. Since Cumulative TSN 3450 * Ack is monotonically increasing, a SACK whose 3451 * Cumulative TSN Ack is less than the Cumulative TSN Ack 3452 * Point indicates an out-of-order SACK. 3453 */ 3454 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 3455 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 3456 asoc->ctsn_ack_point); 3457 3458 return SCTP_DISPOSITION_DISCARD; 3459 } 3460 3461 /* Return this SACK for further processing. */ 3462 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk)); 3463 3464 /* Note: We do the rest of the work on the PROCESS_SACK 3465 * sideeffect. 3466 */ 3467 return SCTP_DISPOSITION_CONSUME; 3468 } 3469 3470 /* 3471 * Generate an ABORT in response to a packet. 3472 * 3473 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 3474 * 3475 * 8) The receiver should respond to the sender of the OOTB packet with 3476 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3477 * MUST fill in the Verification Tag field of the outbound packet 3478 * with the value found in the Verification Tag field of the OOTB 3479 * packet and set the T-bit in the Chunk Flags to indicate that the 3480 * Verification Tag is reflected. After sending this ABORT, the 3481 * receiver of the OOTB packet shall discard the OOTB packet and take 3482 * no further action. 3483 * 3484 * Verification Tag: 3485 * 3486 * The return value is the disposition of the chunk. 3487 */ 3488 static enum sctp_disposition sctp_sf_tabort_8_4_8( 3489 struct net *net, 3490 const struct sctp_endpoint *ep, 3491 const struct sctp_association *asoc, 3492 const union sctp_subtype type, 3493 void *arg, 3494 struct sctp_cmd_seq *commands) 3495 { 3496 struct sctp_packet *packet = NULL; 3497 struct sctp_chunk *chunk = arg; 3498 struct sctp_chunk *abort; 3499 3500 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3501 if (!packet) 3502 return SCTP_DISPOSITION_NOMEM; 3503 3504 /* Make an ABORT. The T bit will be set if the asoc 3505 * is NULL. 3506 */ 3507 abort = sctp_make_abort(asoc, chunk, 0); 3508 if (!abort) { 3509 sctp_ootb_pkt_free(packet); 3510 return SCTP_DISPOSITION_NOMEM; 3511 } 3512 3513 /* Reflect vtag if T-Bit is set */ 3514 if (sctp_test_T_bit(abort)) 3515 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3516 3517 /* Set the skb to the belonging sock for accounting. */ 3518 abort->skb->sk = ep->base.sk; 3519 3520 sctp_packet_append_chunk(packet, abort); 3521 3522 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(packet)); 3523 3524 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3525 3526 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3527 return SCTP_DISPOSITION_CONSUME; 3528 } 3529 3530 /* Handling of SCTP Packets Containing an INIT Chunk Matching an 3531 * Existing Associations when the UDP encap port is incorrect. 3532 * 3533 * From Section 4 at draft-tuexen-tsvwg-sctp-udp-encaps-cons-03. 3534 */ 3535 static enum sctp_disposition sctp_sf_new_encap_port( 3536 struct net *net, 3537 const struct sctp_endpoint *ep, 3538 const struct sctp_association *asoc, 3539 const union sctp_subtype type, 3540 void *arg, 3541 struct sctp_cmd_seq *commands) 3542 { 3543 struct sctp_packet *packet = NULL; 3544 struct sctp_chunk *chunk = arg; 3545 struct sctp_chunk *abort; 3546 3547 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3548 if (!packet) 3549 return SCTP_DISPOSITION_NOMEM; 3550 3551 abort = sctp_make_new_encap_port(asoc, chunk); 3552 if (!abort) { 3553 sctp_ootb_pkt_free(packet); 3554 return SCTP_DISPOSITION_NOMEM; 3555 } 3556 3557 abort->skb->sk = ep->base.sk; 3558 3559 sctp_packet_append_chunk(packet, abort); 3560 3561 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3562 SCTP_PACKET(packet)); 3563 3564 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3565 3566 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3567 return SCTP_DISPOSITION_CONSUME; 3568 } 3569 3570 /* 3571 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 3572 * event as ULP notification for each cause included in the chunk. 3573 * 3574 * API 5.3.1.3 - SCTP_REMOTE_ERROR 3575 * 3576 * The return value is the disposition of the chunk. 3577 */ 3578 enum sctp_disposition sctp_sf_operr_notify(struct net *net, 3579 const struct sctp_endpoint *ep, 3580 const struct sctp_association *asoc, 3581 const union sctp_subtype type, 3582 void *arg, 3583 struct sctp_cmd_seq *commands) 3584 { 3585 struct sctp_chunk *chunk = arg; 3586 struct sctp_errhdr *err; 3587 3588 if (!sctp_vtag_verify(chunk, asoc)) 3589 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3590 3591 /* Make sure that the ERROR chunk has a valid length. */ 3592 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk))) 3593 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3594 commands); 3595 sctp_walk_errors(err, chunk->chunk_hdr); 3596 if ((void *)err != (void *)chunk->chunk_end) 3597 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3598 (void *)err, commands); 3599 3600 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 3601 SCTP_CHUNK(chunk)); 3602 3603 return SCTP_DISPOSITION_CONSUME; 3604 } 3605 3606 /* 3607 * Process an inbound SHUTDOWN ACK. 3608 * 3609 * From Section 9.2: 3610 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3611 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 3612 * peer, and remove all record of the association. 3613 * 3614 * The return value is the disposition. 3615 */ 3616 enum sctp_disposition sctp_sf_do_9_2_final(struct net *net, 3617 const struct sctp_endpoint *ep, 3618 const struct sctp_association *asoc, 3619 const union sctp_subtype type, 3620 void *arg, 3621 struct sctp_cmd_seq *commands) 3622 { 3623 struct sctp_chunk *chunk = arg; 3624 struct sctp_chunk *reply; 3625 struct sctp_ulpevent *ev; 3626 3627 if (!sctp_vtag_verify(chunk, asoc)) 3628 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3629 3630 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3631 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3632 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3633 commands); 3634 /* 10.2 H) SHUTDOWN COMPLETE notification 3635 * 3636 * When SCTP completes the shutdown procedures (section 9.2) this 3637 * notification is passed to the upper layer. 3638 */ 3639 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3640 0, 0, 0, NULL, GFP_ATOMIC); 3641 if (!ev) 3642 goto nomem; 3643 3644 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3645 reply = sctp_make_shutdown_complete(asoc, chunk); 3646 if (!reply) 3647 goto nomem_chunk; 3648 3649 /* Do all the commands now (after allocation), so that we 3650 * have consistent state if memory allocation fails 3651 */ 3652 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3653 3654 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3655 * stop the T2-shutdown timer, 3656 */ 3657 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3658 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3659 3660 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3661 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3662 3663 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3664 SCTP_STATE(SCTP_STATE_CLOSED)); 3665 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 3666 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3667 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3668 3669 /* ...and remove all record of the association. */ 3670 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3671 return SCTP_DISPOSITION_DELETE_TCB; 3672 3673 nomem_chunk: 3674 sctp_ulpevent_free(ev); 3675 nomem: 3676 return SCTP_DISPOSITION_NOMEM; 3677 } 3678 3679 /* 3680 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3681 * 3682 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3683 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3684 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3685 * packet must fill in the Verification Tag field of the outbound 3686 * packet with the Verification Tag received in the SHUTDOWN ACK and 3687 * set the T-bit in the Chunk Flags to indicate that the Verification 3688 * Tag is reflected. 3689 * 3690 * 8) The receiver should respond to the sender of the OOTB packet with 3691 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3692 * MUST fill in the Verification Tag field of the outbound packet 3693 * with the value found in the Verification Tag field of the OOTB 3694 * packet and set the T-bit in the Chunk Flags to indicate that the 3695 * Verification Tag is reflected. After sending this ABORT, the 3696 * receiver of the OOTB packet shall discard the OOTB packet and take 3697 * no further action. 3698 */ 3699 enum sctp_disposition sctp_sf_ootb(struct net *net, 3700 const struct sctp_endpoint *ep, 3701 const struct sctp_association *asoc, 3702 const union sctp_subtype type, 3703 void *arg, struct sctp_cmd_seq *commands) 3704 { 3705 struct sctp_chunk *chunk = arg; 3706 struct sk_buff *skb = chunk->skb; 3707 struct sctp_chunkhdr *ch; 3708 struct sctp_errhdr *err; 3709 int ootb_cookie_ack = 0; 3710 int ootb_shut_ack = 0; 3711 __u8 *ch_end; 3712 3713 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3714 3715 if (asoc && !sctp_vtag_verify(chunk, asoc)) 3716 asoc = NULL; 3717 3718 ch = (struct sctp_chunkhdr *)chunk->chunk_hdr; 3719 do { 3720 /* Report violation if the chunk is less then minimal */ 3721 if (ntohs(ch->length) < sizeof(*ch)) 3722 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3723 commands); 3724 3725 /* Report violation if chunk len overflows */ 3726 ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length)); 3727 if (ch_end > skb_tail_pointer(skb)) 3728 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3729 commands); 3730 3731 /* Now that we know we at least have a chunk header, 3732 * do things that are type appropriate. 3733 */ 3734 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3735 ootb_shut_ack = 1; 3736 3737 /* RFC 2960, Section 3.3.7 3738 * Moreover, under any circumstances, an endpoint that 3739 * receives an ABORT MUST NOT respond to that ABORT by 3740 * sending an ABORT of its own. 3741 */ 3742 if (SCTP_CID_ABORT == ch->type) 3743 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3744 3745 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR 3746 * or a COOKIE ACK the SCTP Packet should be silently 3747 * discarded. 3748 */ 3749 3750 if (SCTP_CID_COOKIE_ACK == ch->type) 3751 ootb_cookie_ack = 1; 3752 3753 if (SCTP_CID_ERROR == ch->type) { 3754 sctp_walk_errors(err, ch) { 3755 if (SCTP_ERROR_STALE_COOKIE == err->cause) { 3756 ootb_cookie_ack = 1; 3757 break; 3758 } 3759 } 3760 } 3761 3762 ch = (struct sctp_chunkhdr *)ch_end; 3763 } while (ch_end + sizeof(*ch) < skb_tail_pointer(skb)); 3764 3765 if (ootb_shut_ack) 3766 return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands); 3767 else if (ootb_cookie_ack) 3768 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3769 else 3770 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 3771 } 3772 3773 /* 3774 * Handle an "Out of the blue" SHUTDOWN ACK. 3775 * 3776 * Section: 8.4 5, sctpimpguide 2.41. 3777 * 3778 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3779 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3780 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3781 * packet must fill in the Verification Tag field of the outbound 3782 * packet with the Verification Tag received in the SHUTDOWN ACK and 3783 * set the T-bit in the Chunk Flags to indicate that the Verification 3784 * Tag is reflected. 3785 * 3786 * Inputs 3787 * (endpoint, asoc, type, arg, commands) 3788 * 3789 * Outputs 3790 * (enum sctp_disposition) 3791 * 3792 * The return value is the disposition of the chunk. 3793 */ 3794 static enum sctp_disposition sctp_sf_shut_8_4_5( 3795 struct net *net, 3796 const struct sctp_endpoint *ep, 3797 const struct sctp_association *asoc, 3798 const union sctp_subtype type, 3799 void *arg, 3800 struct sctp_cmd_seq *commands) 3801 { 3802 struct sctp_packet *packet = NULL; 3803 struct sctp_chunk *chunk = arg; 3804 struct sctp_chunk *shut; 3805 3806 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3807 if (!packet) 3808 return SCTP_DISPOSITION_NOMEM; 3809 3810 /* Make an SHUTDOWN_COMPLETE. 3811 * The T bit will be set if the asoc is NULL. 3812 */ 3813 shut = sctp_make_shutdown_complete(asoc, chunk); 3814 if (!shut) { 3815 sctp_ootb_pkt_free(packet); 3816 return SCTP_DISPOSITION_NOMEM; 3817 } 3818 3819 /* Reflect vtag if T-Bit is set */ 3820 if (sctp_test_T_bit(shut)) 3821 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3822 3823 /* Set the skb to the belonging sock for accounting. */ 3824 shut->skb->sk = ep->base.sk; 3825 3826 sctp_packet_append_chunk(packet, shut); 3827 3828 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3829 SCTP_PACKET(packet)); 3830 3831 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3832 3833 /* We need to discard the rest of the packet to prevent 3834 * potential boomming attacks from additional bundled chunks. 3835 * This is documented in SCTP Threats ID. 3836 */ 3837 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3838 } 3839 3840 /* 3841 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3842 * 3843 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3844 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3845 * procedures in section 8.4 SHOULD be followed, in other words it 3846 * should be treated as an Out Of The Blue packet. 3847 * [This means that we do NOT check the Verification Tag on these 3848 * chunks. --piggy ] 3849 * 3850 */ 3851 enum sctp_disposition sctp_sf_do_8_5_1_E_sa(struct net *net, 3852 const struct sctp_endpoint *ep, 3853 const struct sctp_association *asoc, 3854 const union sctp_subtype type, 3855 void *arg, 3856 struct sctp_cmd_seq *commands) 3857 { 3858 struct sctp_chunk *chunk = arg; 3859 3860 if (!sctp_vtag_verify(chunk, asoc)) 3861 asoc = NULL; 3862 3863 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3864 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3865 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3866 commands); 3867 3868 /* Although we do have an association in this case, it corresponds 3869 * to a restarted association. So the packet is treated as an OOTB 3870 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3871 * called with a NULL association. 3872 */ 3873 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3874 3875 return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands); 3876 } 3877 3878 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3879 enum sctp_disposition sctp_sf_do_asconf(struct net *net, 3880 const struct sctp_endpoint *ep, 3881 const struct sctp_association *asoc, 3882 const union sctp_subtype type, 3883 void *arg, 3884 struct sctp_cmd_seq *commands) 3885 { 3886 struct sctp_paramhdr *err_param = NULL; 3887 struct sctp_chunk *asconf_ack = NULL; 3888 struct sctp_chunk *chunk = arg; 3889 struct sctp_addiphdr *hdr; 3890 __u32 serial; 3891 3892 if (!sctp_vtag_verify(chunk, asoc)) { 3893 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3894 SCTP_NULL()); 3895 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3896 } 3897 3898 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3899 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_addip_chunk))) 3900 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3901 commands); 3902 3903 /* ADD-IP: Section 4.1.1 3904 * This chunk MUST be sent in an authenticated way by using 3905 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3906 * is received unauthenticated it MUST be silently discarded as 3907 * described in [I-D.ietf-tsvwg-sctp-auth]. 3908 */ 3909 if (!asoc->peer.asconf_capable || 3910 (!net->sctp.addip_noauth && !chunk->auth)) 3911 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3912 3913 hdr = (struct sctp_addiphdr *)chunk->skb->data; 3914 serial = ntohl(hdr->serial); 3915 3916 /* Verify the ASCONF chunk before processing it. */ 3917 if (!sctp_verify_asconf(asoc, chunk, true, &err_param)) 3918 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3919 (void *)err_param, commands); 3920 3921 /* ADDIP 5.2 E1) Compare the value of the serial number to the value 3922 * the endpoint stored in a new association variable 3923 * 'Peer-Serial-Number'. 3924 */ 3925 if (serial == asoc->peer.addip_serial + 1) { 3926 /* If this is the first instance of ASCONF in the packet, 3927 * we can clean our old ASCONF-ACKs. 3928 */ 3929 if (!chunk->has_asconf) 3930 sctp_assoc_clean_asconf_ack_cache(asoc); 3931 3932 /* ADDIP 5.2 E4) When the Sequence Number matches the next one 3933 * expected, process the ASCONF as described below and after 3934 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to 3935 * the response packet and cache a copy of it (in the event it 3936 * later needs to be retransmitted). 3937 * 3938 * Essentially, do V1-V5. 3939 */ 3940 asconf_ack = sctp_process_asconf((struct sctp_association *) 3941 asoc, chunk); 3942 if (!asconf_ack) 3943 return SCTP_DISPOSITION_NOMEM; 3944 } else if (serial < asoc->peer.addip_serial + 1) { 3945 /* ADDIP 5.2 E2) 3946 * If the value found in the Sequence Number is less than the 3947 * ('Peer- Sequence-Number' + 1), simply skip to the next 3948 * ASCONF, and include in the outbound response packet 3949 * any previously cached ASCONF-ACK response that was 3950 * sent and saved that matches the Sequence Number of the 3951 * ASCONF. Note: It is possible that no cached ASCONF-ACK 3952 * Chunk exists. This will occur when an older ASCONF 3953 * arrives out of order. In such a case, the receiver 3954 * should skip the ASCONF Chunk and not include ASCONF-ACK 3955 * Chunk for that chunk. 3956 */ 3957 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial); 3958 if (!asconf_ack) 3959 return SCTP_DISPOSITION_DISCARD; 3960 3961 /* Reset the transport so that we select the correct one 3962 * this time around. This is to make sure that we don't 3963 * accidentally use a stale transport that's been removed. 3964 */ 3965 asconf_ack->transport = NULL; 3966 } else { 3967 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since 3968 * it must be either a stale packet or from an attacker. 3969 */ 3970 return SCTP_DISPOSITION_DISCARD; 3971 } 3972 3973 /* ADDIP 5.2 E6) The destination address of the SCTP packet 3974 * containing the ASCONF-ACK Chunks MUST be the source address of 3975 * the SCTP packet that held the ASCONF Chunks. 3976 * 3977 * To do this properly, we'll set the destination address of the chunk 3978 * and at the transmit time, will try look up the transport to use. 3979 * Since ASCONFs may be bundled, the correct transport may not be 3980 * created until we process the entire packet, thus this workaround. 3981 */ 3982 asconf_ack->dest = chunk->source; 3983 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3984 if (asoc->new_transport) { 3985 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, commands); 3986 ((struct sctp_association *)asoc)->new_transport = NULL; 3987 } 3988 3989 return SCTP_DISPOSITION_CONSUME; 3990 } 3991 3992 static enum sctp_disposition sctp_send_next_asconf( 3993 struct net *net, 3994 const struct sctp_endpoint *ep, 3995 struct sctp_association *asoc, 3996 const union sctp_subtype type, 3997 struct sctp_cmd_seq *commands) 3998 { 3999 struct sctp_chunk *asconf; 4000 struct list_head *entry; 4001 4002 if (list_empty(&asoc->addip_chunk_list)) 4003 return SCTP_DISPOSITION_CONSUME; 4004 4005 entry = asoc->addip_chunk_list.next; 4006 asconf = list_entry(entry, struct sctp_chunk, list); 4007 4008 list_del_init(entry); 4009 sctp_chunk_hold(asconf); 4010 asoc->addip_last_asconf = asconf; 4011 4012 return sctp_sf_do_prm_asconf(net, ep, asoc, type, asconf, commands); 4013 } 4014 4015 /* 4016 * ADDIP Section 4.3 General rules for address manipulation 4017 * When building TLV parameters for the ASCONF Chunk that will add or 4018 * delete IP addresses the D0 to D13 rules should be applied: 4019 */ 4020 enum sctp_disposition sctp_sf_do_asconf_ack(struct net *net, 4021 const struct sctp_endpoint *ep, 4022 const struct sctp_association *asoc, 4023 const union sctp_subtype type, 4024 void *arg, 4025 struct sctp_cmd_seq *commands) 4026 { 4027 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 4028 struct sctp_paramhdr *err_param = NULL; 4029 struct sctp_chunk *asconf_ack = arg; 4030 struct sctp_addiphdr *addip_hdr; 4031 __u32 sent_serial, rcvd_serial; 4032 struct sctp_chunk *abort; 4033 4034 if (!sctp_vtag_verify(asconf_ack, asoc)) { 4035 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4036 SCTP_NULL()); 4037 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4038 } 4039 4040 /* Make sure that the ADDIP chunk has a valid length. */ 4041 if (!sctp_chunk_length_valid(asconf_ack, 4042 sizeof(struct sctp_addip_chunk))) 4043 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4044 commands); 4045 4046 /* ADD-IP, Section 4.1.2: 4047 * This chunk MUST be sent in an authenticated way by using 4048 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 4049 * is received unauthenticated it MUST be silently discarded as 4050 * described in [I-D.ietf-tsvwg-sctp-auth]. 4051 */ 4052 if (!asoc->peer.asconf_capable || 4053 (!net->sctp.addip_noauth && !asconf_ack->auth)) 4054 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4055 4056 addip_hdr = (struct sctp_addiphdr *)asconf_ack->skb->data; 4057 rcvd_serial = ntohl(addip_hdr->serial); 4058 4059 /* Verify the ASCONF-ACK chunk before processing it. */ 4060 if (!sctp_verify_asconf(asoc, asconf_ack, false, &err_param)) 4061 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 4062 (void *)err_param, commands); 4063 4064 if (last_asconf) { 4065 addip_hdr = last_asconf->subh.addip_hdr; 4066 sent_serial = ntohl(addip_hdr->serial); 4067 } else { 4068 sent_serial = asoc->addip_serial - 1; 4069 } 4070 4071 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 4072 * equal to the next serial number to be used but no ASCONF chunk is 4073 * outstanding the endpoint MUST ABORT the association. Note that a 4074 * sequence number is greater than if it is no more than 2^^31-1 4075 * larger than the current sequence number (using serial arithmetic). 4076 */ 4077 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 4078 !(asoc->addip_last_asconf)) { 4079 abort = sctp_make_abort(asoc, asconf_ack, 4080 sizeof(struct sctp_errhdr)); 4081 if (abort) { 4082 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0); 4083 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4084 SCTP_CHUNK(abort)); 4085 } 4086 /* We are going to ABORT, so we might as well stop 4087 * processing the rest of the chunks in the packet. 4088 */ 4089 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4090 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 4091 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4092 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4093 SCTP_ERROR(ECONNABORTED)); 4094 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4095 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 4096 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4097 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4098 return SCTP_DISPOSITION_ABORT; 4099 } 4100 4101 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 4102 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4103 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 4104 4105 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 4106 asconf_ack)) 4107 return sctp_send_next_asconf(net, ep, 4108 (struct sctp_association *)asoc, 4109 type, commands); 4110 4111 abort = sctp_make_abort(asoc, asconf_ack, 4112 sizeof(struct sctp_errhdr)); 4113 if (abort) { 4114 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 4115 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4116 SCTP_CHUNK(abort)); 4117 } 4118 /* We are going to ABORT, so we might as well stop 4119 * processing the rest of the chunks in the packet. 4120 */ 4121 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4122 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4123 SCTP_ERROR(ECONNABORTED)); 4124 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4125 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 4126 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4127 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4128 return SCTP_DISPOSITION_ABORT; 4129 } 4130 4131 return SCTP_DISPOSITION_DISCARD; 4132 } 4133 4134 /* RE-CONFIG Section 5.2 Upon reception of an RECONF Chunk. */ 4135 enum sctp_disposition sctp_sf_do_reconf(struct net *net, 4136 const struct sctp_endpoint *ep, 4137 const struct sctp_association *asoc, 4138 const union sctp_subtype type, 4139 void *arg, 4140 struct sctp_cmd_seq *commands) 4141 { 4142 struct sctp_paramhdr *err_param = NULL; 4143 struct sctp_chunk *chunk = arg; 4144 struct sctp_reconf_chunk *hdr; 4145 union sctp_params param; 4146 4147 if (!sctp_vtag_verify(chunk, asoc)) { 4148 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4149 SCTP_NULL()); 4150 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4151 } 4152 4153 /* Make sure that the RECONF chunk has a valid length. */ 4154 if (!sctp_chunk_length_valid(chunk, sizeof(*hdr))) 4155 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4156 commands); 4157 4158 if (!sctp_verify_reconf(asoc, chunk, &err_param)) 4159 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 4160 (void *)err_param, commands); 4161 4162 hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr; 4163 sctp_walk_params(param, hdr) { 4164 struct sctp_chunk *reply = NULL; 4165 struct sctp_ulpevent *ev = NULL; 4166 4167 if (param.p->type == SCTP_PARAM_RESET_OUT_REQUEST) 4168 reply = sctp_process_strreset_outreq( 4169 (struct sctp_association *)asoc, param, &ev); 4170 else if (param.p->type == SCTP_PARAM_RESET_IN_REQUEST) 4171 reply = sctp_process_strreset_inreq( 4172 (struct sctp_association *)asoc, param, &ev); 4173 else if (param.p->type == SCTP_PARAM_RESET_TSN_REQUEST) 4174 reply = sctp_process_strreset_tsnreq( 4175 (struct sctp_association *)asoc, param, &ev); 4176 else if (param.p->type == SCTP_PARAM_RESET_ADD_OUT_STREAMS) 4177 reply = sctp_process_strreset_addstrm_out( 4178 (struct sctp_association *)asoc, param, &ev); 4179 else if (param.p->type == SCTP_PARAM_RESET_ADD_IN_STREAMS) 4180 reply = sctp_process_strreset_addstrm_in( 4181 (struct sctp_association *)asoc, param, &ev); 4182 else if (param.p->type == SCTP_PARAM_RESET_RESPONSE) 4183 reply = sctp_process_strreset_resp( 4184 (struct sctp_association *)asoc, param, &ev); 4185 4186 if (ev) 4187 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4188 SCTP_ULPEVENT(ev)); 4189 4190 if (reply) 4191 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4192 SCTP_CHUNK(reply)); 4193 } 4194 4195 return SCTP_DISPOSITION_CONSUME; 4196 } 4197 4198 /* 4199 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 4200 * 4201 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 4202 * its cumulative TSN point to the value carried in the FORWARD TSN 4203 * chunk, and then MUST further advance its cumulative TSN point locally 4204 * if possible. 4205 * After the above processing, the data receiver MUST stop reporting any 4206 * missing TSNs earlier than or equal to the new cumulative TSN point. 4207 * 4208 * Verification Tag: 8.5 Verification Tag [Normal verification] 4209 * 4210 * The return value is the disposition of the chunk. 4211 */ 4212 enum sctp_disposition sctp_sf_eat_fwd_tsn(struct net *net, 4213 const struct sctp_endpoint *ep, 4214 const struct sctp_association *asoc, 4215 const union sctp_subtype type, 4216 void *arg, 4217 struct sctp_cmd_seq *commands) 4218 { 4219 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 4220 struct sctp_chunk *chunk = arg; 4221 __u16 len; 4222 __u32 tsn; 4223 4224 if (!sctp_vtag_verify(chunk, asoc)) { 4225 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4226 SCTP_NULL()); 4227 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4228 } 4229 4230 if (!asoc->peer.prsctp_capable) 4231 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4232 4233 /* Make sure that the FORWARD_TSN chunk has valid length. */ 4234 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream))) 4235 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4236 commands); 4237 4238 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 4239 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 4240 len = ntohs(chunk->chunk_hdr->length); 4241 len -= sizeof(struct sctp_chunkhdr); 4242 skb_pull(chunk->skb, len); 4243 4244 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 4245 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 4246 4247 /* The TSN is too high--silently discard the chunk and count on it 4248 * getting retransmitted later. 4249 */ 4250 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 4251 goto discard_noforce; 4252 4253 if (!asoc->stream.si->validate_ftsn(chunk)) 4254 goto discard_noforce; 4255 4256 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 4257 if (len > sctp_ftsnhdr_len(&asoc->stream)) 4258 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 4259 SCTP_CHUNK(chunk)); 4260 4261 /* Count this as receiving DATA. */ 4262 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 4263 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4264 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 4265 } 4266 4267 /* FIXME: For now send a SACK, but DATA processing may 4268 * send another. 4269 */ 4270 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 4271 4272 return SCTP_DISPOSITION_CONSUME; 4273 4274 discard_noforce: 4275 return SCTP_DISPOSITION_DISCARD; 4276 } 4277 4278 enum sctp_disposition sctp_sf_eat_fwd_tsn_fast( 4279 struct net *net, 4280 const struct sctp_endpoint *ep, 4281 const struct sctp_association *asoc, 4282 const union sctp_subtype type, 4283 void *arg, 4284 struct sctp_cmd_seq *commands) 4285 { 4286 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 4287 struct sctp_chunk *chunk = arg; 4288 __u16 len; 4289 __u32 tsn; 4290 4291 if (!sctp_vtag_verify(chunk, asoc)) { 4292 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4293 SCTP_NULL()); 4294 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4295 } 4296 4297 if (!asoc->peer.prsctp_capable) 4298 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4299 4300 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 4301 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream))) 4302 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4303 commands); 4304 4305 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 4306 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 4307 len = ntohs(chunk->chunk_hdr->length); 4308 len -= sizeof(struct sctp_chunkhdr); 4309 skb_pull(chunk->skb, len); 4310 4311 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 4312 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 4313 4314 /* The TSN is too high--silently discard the chunk and count on it 4315 * getting retransmitted later. 4316 */ 4317 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 4318 goto gen_shutdown; 4319 4320 if (!asoc->stream.si->validate_ftsn(chunk)) 4321 goto gen_shutdown; 4322 4323 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 4324 if (len > sctp_ftsnhdr_len(&asoc->stream)) 4325 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 4326 SCTP_CHUNK(chunk)); 4327 4328 /* Go a head and force a SACK, since we are shutting down. */ 4329 gen_shutdown: 4330 /* Implementor's Guide. 4331 * 4332 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 4333 * respond to each received packet containing one or more DATA chunk(s) 4334 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 4335 */ 4336 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 4337 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 4338 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4339 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4340 4341 return SCTP_DISPOSITION_CONSUME; 4342 } 4343 4344 /* 4345 * SCTP-AUTH Section 6.3 Receiving authenticated chunks 4346 * 4347 * The receiver MUST use the HMAC algorithm indicated in the HMAC 4348 * Identifier field. If this algorithm was not specified by the 4349 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk 4350 * during association setup, the AUTH chunk and all chunks after it MUST 4351 * be discarded and an ERROR chunk SHOULD be sent with the error cause 4352 * defined in Section 4.1. 4353 * 4354 * If an endpoint with no shared key receives a Shared Key Identifier 4355 * other than 0, it MUST silently discard all authenticated chunks. If 4356 * the endpoint has at least one endpoint pair shared key for the peer, 4357 * it MUST use the key specified by the Shared Key Identifier if a 4358 * key has been configured for that Shared Key Identifier. If no 4359 * endpoint pair shared key has been configured for that Shared Key 4360 * Identifier, all authenticated chunks MUST be silently discarded. 4361 * 4362 * Verification Tag: 8.5 Verification Tag [Normal verification] 4363 * 4364 * The return value is the disposition of the chunk. 4365 */ 4366 static enum sctp_ierror sctp_sf_authenticate( 4367 const struct sctp_association *asoc, 4368 struct sctp_chunk *chunk) 4369 { 4370 struct sctp_shared_key *sh_key = NULL; 4371 struct sctp_authhdr *auth_hdr; 4372 __u8 *save_digest, *digest; 4373 const struct sctp_hmac *hmac; 4374 unsigned int sig_len; 4375 __u16 key_id; 4376 4377 /* Pull in the auth header, so we can do some more verification */ 4378 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4379 chunk->subh.auth_hdr = auth_hdr; 4380 skb_pull(chunk->skb, sizeof(*auth_hdr)); 4381 4382 /* Make sure that we support the HMAC algorithm from the auth 4383 * chunk. 4384 */ 4385 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id)) 4386 return SCTP_IERROR_AUTH_BAD_HMAC; 4387 4388 /* Make sure that the provided shared key identifier has been 4389 * configured 4390 */ 4391 key_id = ntohs(auth_hdr->shkey_id); 4392 if (key_id != asoc->active_key_id) { 4393 sh_key = sctp_auth_get_shkey(asoc, key_id); 4394 if (!sh_key) 4395 return SCTP_IERROR_AUTH_BAD_KEYID; 4396 } 4397 4398 /* Make sure that the length of the signature matches what 4399 * we expect. 4400 */ 4401 sig_len = ntohs(chunk->chunk_hdr->length) - 4402 sizeof(struct sctp_auth_chunk); 4403 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id)); 4404 if (sig_len != hmac->hmac_len) 4405 return SCTP_IERROR_PROTO_VIOLATION; 4406 4407 /* Now that we've done validation checks, we can compute and 4408 * verify the hmac. The steps involved are: 4409 * 1. Save the digest from the chunk. 4410 * 2. Zero out the digest in the chunk. 4411 * 3. Compute the new digest 4412 * 4. Compare saved and new digests. 4413 */ 4414 digest = (u8 *)(auth_hdr + 1); 4415 skb_pull(chunk->skb, sig_len); 4416 4417 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC); 4418 if (!save_digest) 4419 goto nomem; 4420 4421 memset(digest, 0, sig_len); 4422 4423 sctp_auth_calculate_hmac(asoc, chunk->skb, 4424 (struct sctp_auth_chunk *)chunk->chunk_hdr, 4425 sh_key, GFP_ATOMIC); 4426 4427 /* Discard the packet if the digests do not match */ 4428 if (crypto_memneq(save_digest, digest, sig_len)) { 4429 kfree(save_digest); 4430 return SCTP_IERROR_BAD_SIG; 4431 } 4432 4433 kfree(save_digest); 4434 chunk->auth = 1; 4435 4436 return SCTP_IERROR_NO_ERROR; 4437 nomem: 4438 return SCTP_IERROR_NOMEM; 4439 } 4440 4441 enum sctp_disposition sctp_sf_eat_auth(struct net *net, 4442 const struct sctp_endpoint *ep, 4443 const struct sctp_association *asoc, 4444 const union sctp_subtype type, 4445 void *arg, struct sctp_cmd_seq *commands) 4446 { 4447 struct sctp_chunk *chunk = arg; 4448 struct sctp_authhdr *auth_hdr; 4449 struct sctp_chunk *err_chunk; 4450 enum sctp_ierror error; 4451 4452 /* Make sure that the peer has AUTH capable */ 4453 if (!asoc->peer.auth_capable) 4454 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4455 4456 if (!sctp_vtag_verify(chunk, asoc)) { 4457 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4458 SCTP_NULL()); 4459 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4460 } 4461 4462 /* Make sure that the AUTH chunk has valid length. */ 4463 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk))) 4464 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4465 commands); 4466 4467 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4468 error = sctp_sf_authenticate(asoc, chunk); 4469 switch (error) { 4470 case SCTP_IERROR_AUTH_BAD_HMAC: 4471 /* Generate the ERROR chunk and discard the rest 4472 * of the packet 4473 */ 4474 err_chunk = sctp_make_op_error(asoc, chunk, 4475 SCTP_ERROR_UNSUP_HMAC, 4476 &auth_hdr->hmac_id, 4477 sizeof(__u16), 0); 4478 if (err_chunk) { 4479 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4480 SCTP_CHUNK(err_chunk)); 4481 } 4482 fallthrough; 4483 case SCTP_IERROR_AUTH_BAD_KEYID: 4484 case SCTP_IERROR_BAD_SIG: 4485 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4486 4487 case SCTP_IERROR_PROTO_VIOLATION: 4488 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4489 commands); 4490 4491 case SCTP_IERROR_NOMEM: 4492 return SCTP_DISPOSITION_NOMEM; 4493 4494 default: /* Prevent gcc warnings */ 4495 break; 4496 } 4497 4498 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) { 4499 struct sctp_ulpevent *ev; 4500 4501 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id), 4502 SCTP_AUTH_NEW_KEY, GFP_ATOMIC); 4503 4504 if (!ev) 4505 return SCTP_DISPOSITION_NOMEM; 4506 4507 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4508 SCTP_ULPEVENT(ev)); 4509 } 4510 4511 return SCTP_DISPOSITION_CONSUME; 4512 } 4513 4514 /* 4515 * Process an unknown chunk. 4516 * 4517 * Section: 3.2. Also, 2.1 in the implementor's guide. 4518 * 4519 * Chunk Types are encoded such that the highest-order two bits specify 4520 * the action that must be taken if the processing endpoint does not 4521 * recognize the Chunk Type. 4522 * 4523 * 00 - Stop processing this SCTP packet and discard it, do not process 4524 * any further chunks within it. 4525 * 4526 * 01 - Stop processing this SCTP packet and discard it, do not process 4527 * any further chunks within it, and report the unrecognized 4528 * chunk in an 'Unrecognized Chunk Type'. 4529 * 4530 * 10 - Skip this chunk and continue processing. 4531 * 4532 * 11 - Skip this chunk and continue processing, but report in an ERROR 4533 * Chunk using the 'Unrecognized Chunk Type' cause of error. 4534 * 4535 * The return value is the disposition of the chunk. 4536 */ 4537 enum sctp_disposition sctp_sf_unk_chunk(struct net *net, 4538 const struct sctp_endpoint *ep, 4539 const struct sctp_association *asoc, 4540 const union sctp_subtype type, 4541 void *arg, 4542 struct sctp_cmd_seq *commands) 4543 { 4544 struct sctp_chunk *unk_chunk = arg; 4545 struct sctp_chunk *err_chunk; 4546 struct sctp_chunkhdr *hdr; 4547 4548 pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk); 4549 4550 if (!sctp_vtag_verify(unk_chunk, asoc)) 4551 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4552 4553 /* Make sure that the chunk has a valid length. 4554 * Since we don't know the chunk type, we use a general 4555 * chunkhdr structure to make a comparison. 4556 */ 4557 if (!sctp_chunk_length_valid(unk_chunk, sizeof(*hdr))) 4558 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4559 commands); 4560 4561 switch (type.chunk & SCTP_CID_ACTION_MASK) { 4562 case SCTP_CID_ACTION_DISCARD: 4563 /* Discard the packet. */ 4564 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4565 case SCTP_CID_ACTION_DISCARD_ERR: 4566 /* Generate an ERROR chunk as response. */ 4567 hdr = unk_chunk->chunk_hdr; 4568 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4569 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4570 SCTP_PAD4(ntohs(hdr->length)), 4571 0); 4572 if (err_chunk) { 4573 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4574 SCTP_CHUNK(err_chunk)); 4575 } 4576 4577 /* Discard the packet. */ 4578 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4579 return SCTP_DISPOSITION_CONSUME; 4580 case SCTP_CID_ACTION_SKIP: 4581 /* Skip the chunk. */ 4582 return SCTP_DISPOSITION_DISCARD; 4583 case SCTP_CID_ACTION_SKIP_ERR: 4584 /* Generate an ERROR chunk as response. */ 4585 hdr = unk_chunk->chunk_hdr; 4586 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4587 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4588 SCTP_PAD4(ntohs(hdr->length)), 4589 0); 4590 if (err_chunk) { 4591 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4592 SCTP_CHUNK(err_chunk)); 4593 } 4594 /* Skip the chunk. */ 4595 return SCTP_DISPOSITION_CONSUME; 4596 default: 4597 break; 4598 } 4599 4600 return SCTP_DISPOSITION_DISCARD; 4601 } 4602 4603 /* 4604 * Discard the chunk. 4605 * 4606 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 4607 * [Too numerous to mention...] 4608 * Verification Tag: No verification needed. 4609 * Inputs 4610 * (endpoint, asoc, chunk) 4611 * 4612 * Outputs 4613 * (asoc, reply_msg, msg_up, timers, counters) 4614 * 4615 * The return value is the disposition of the chunk. 4616 */ 4617 enum sctp_disposition sctp_sf_discard_chunk(struct net *net, 4618 const struct sctp_endpoint *ep, 4619 const struct sctp_association *asoc, 4620 const union sctp_subtype type, 4621 void *arg, 4622 struct sctp_cmd_seq *commands) 4623 { 4624 struct sctp_chunk *chunk = arg; 4625 4626 if (asoc && !sctp_vtag_verify(chunk, asoc)) 4627 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4628 4629 /* Make sure that the chunk has a valid length. 4630 * Since we don't know the chunk type, we use a general 4631 * chunkhdr structure to make a comparison. 4632 */ 4633 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 4634 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4635 commands); 4636 4637 pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk); 4638 4639 return SCTP_DISPOSITION_DISCARD; 4640 } 4641 4642 /* 4643 * Discard the whole packet. 4644 * 4645 * Section: 8.4 2) 4646 * 4647 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 4648 * silently discard the OOTB packet and take no further action. 4649 * 4650 * Verification Tag: No verification necessary 4651 * 4652 * Inputs 4653 * (endpoint, asoc, chunk) 4654 * 4655 * Outputs 4656 * (asoc, reply_msg, msg_up, timers, counters) 4657 * 4658 * The return value is the disposition of the chunk. 4659 */ 4660 enum sctp_disposition sctp_sf_pdiscard(struct net *net, 4661 const struct sctp_endpoint *ep, 4662 const struct sctp_association *asoc, 4663 const union sctp_subtype type, 4664 void *arg, struct sctp_cmd_seq *commands) 4665 { 4666 SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS); 4667 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4668 4669 return SCTP_DISPOSITION_CONSUME; 4670 } 4671 4672 4673 /* 4674 * The other end is violating protocol. 4675 * 4676 * Section: Not specified 4677 * Verification Tag: Not specified 4678 * Inputs 4679 * (endpoint, asoc, chunk) 4680 * 4681 * Outputs 4682 * (asoc, reply_msg, msg_up, timers, counters) 4683 * 4684 * We simply tag the chunk as a violation. The state machine will log 4685 * the violation and continue. 4686 */ 4687 enum sctp_disposition sctp_sf_violation(struct net *net, 4688 const struct sctp_endpoint *ep, 4689 const struct sctp_association *asoc, 4690 const union sctp_subtype type, 4691 void *arg, 4692 struct sctp_cmd_seq *commands) 4693 { 4694 struct sctp_chunk *chunk = arg; 4695 4696 if (!sctp_vtag_verify(chunk, asoc)) 4697 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4698 4699 /* Make sure that the chunk has a valid length. */ 4700 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 4701 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4702 commands); 4703 4704 return SCTP_DISPOSITION_VIOLATION; 4705 } 4706 4707 /* 4708 * Common function to handle a protocol violation. 4709 */ 4710 static enum sctp_disposition sctp_sf_abort_violation( 4711 struct net *net, 4712 const struct sctp_endpoint *ep, 4713 const struct sctp_association *asoc, 4714 void *arg, 4715 struct sctp_cmd_seq *commands, 4716 const __u8 *payload, 4717 const size_t paylen) 4718 { 4719 struct sctp_packet *packet = NULL; 4720 struct sctp_chunk *chunk = arg; 4721 struct sctp_chunk *abort = NULL; 4722 4723 /* SCTP-AUTH, Section 6.3: 4724 * It should be noted that if the receiver wants to tear 4725 * down an association in an authenticated way only, the 4726 * handling of malformed packets should not result in 4727 * tearing down the association. 4728 * 4729 * This means that if we only want to abort associations 4730 * in an authenticated way (i.e AUTH+ABORT), then we 4731 * can't destroy this association just because the packet 4732 * was malformed. 4733 */ 4734 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4735 goto discard; 4736 4737 /* Make the abort chunk. */ 4738 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen); 4739 if (!abort) 4740 goto nomem; 4741 4742 if (asoc) { 4743 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */ 4744 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK && 4745 !asoc->peer.i.init_tag) { 4746 struct sctp_initack_chunk *initack; 4747 4748 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr; 4749 if (!sctp_chunk_length_valid(chunk, sizeof(*initack))) 4750 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T; 4751 else { 4752 unsigned int inittag; 4753 4754 inittag = ntohl(initack->init_hdr.init_tag); 4755 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG, 4756 SCTP_U32(inittag)); 4757 } 4758 } 4759 4760 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4761 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4762 4763 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 4764 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4765 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4766 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4767 SCTP_ERROR(ECONNREFUSED)); 4768 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4769 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4770 } else { 4771 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4772 SCTP_ERROR(ECONNABORTED)); 4773 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4774 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4775 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4776 } 4777 } else { 4778 packet = sctp_ootb_pkt_new(net, asoc, chunk); 4779 4780 if (!packet) 4781 goto nomem_pkt; 4782 4783 if (sctp_test_T_bit(abort)) 4784 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 4785 4786 abort->skb->sk = ep->base.sk; 4787 4788 sctp_packet_append_chunk(packet, abort); 4789 4790 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 4791 SCTP_PACKET(packet)); 4792 4793 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4794 } 4795 4796 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4797 4798 discard: 4799 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4800 return SCTP_DISPOSITION_ABORT; 4801 4802 nomem_pkt: 4803 sctp_chunk_free(abort); 4804 nomem: 4805 return SCTP_DISPOSITION_NOMEM; 4806 } 4807 4808 /* 4809 * Handle a protocol violation when the chunk length is invalid. 4810 * "Invalid" length is identified as smaller than the minimal length a 4811 * given chunk can be. For example, a SACK chunk has invalid length 4812 * if its length is set to be smaller than the size of struct sctp_sack_chunk. 4813 * 4814 * We inform the other end by sending an ABORT with a Protocol Violation 4815 * error code. 4816 * 4817 * Section: Not specified 4818 * Verification Tag: Nothing to do 4819 * Inputs 4820 * (endpoint, asoc, chunk) 4821 * 4822 * Outputs 4823 * (reply_msg, msg_up, counters) 4824 * 4825 * Generate an ABORT chunk and terminate the association. 4826 */ 4827 static enum sctp_disposition sctp_sf_violation_chunklen( 4828 struct net *net, 4829 const struct sctp_endpoint *ep, 4830 const struct sctp_association *asoc, 4831 const union sctp_subtype type, 4832 void *arg, 4833 struct sctp_cmd_seq *commands) 4834 { 4835 static const char err_str[] = "The following chunk had invalid length:"; 4836 4837 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4838 sizeof(err_str)); 4839 } 4840 4841 /* 4842 * Handle a protocol violation when the parameter length is invalid. 4843 * If the length is smaller than the minimum length of a given parameter, 4844 * or accumulated length in multi parameters exceeds the end of the chunk, 4845 * the length is considered as invalid. 4846 */ 4847 static enum sctp_disposition sctp_sf_violation_paramlen( 4848 struct net *net, 4849 const struct sctp_endpoint *ep, 4850 const struct sctp_association *asoc, 4851 const union sctp_subtype type, 4852 void *arg, void *ext, 4853 struct sctp_cmd_seq *commands) 4854 { 4855 struct sctp_paramhdr *param = ext; 4856 struct sctp_chunk *abort = NULL; 4857 struct sctp_chunk *chunk = arg; 4858 4859 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4860 goto discard; 4861 4862 /* Make the abort chunk. */ 4863 abort = sctp_make_violation_paramlen(asoc, chunk, param); 4864 if (!abort) 4865 goto nomem; 4866 4867 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4868 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4869 4870 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4871 SCTP_ERROR(ECONNABORTED)); 4872 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4873 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4874 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4875 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4876 4877 discard: 4878 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4879 return SCTP_DISPOSITION_ABORT; 4880 nomem: 4881 return SCTP_DISPOSITION_NOMEM; 4882 } 4883 4884 /* Handle a protocol violation when the peer trying to advance the 4885 * cumulative tsn ack to a point beyond the max tsn currently sent. 4886 * 4887 * We inform the other end by sending an ABORT with a Protocol Violation 4888 * error code. 4889 */ 4890 static enum sctp_disposition sctp_sf_violation_ctsn( 4891 struct net *net, 4892 const struct sctp_endpoint *ep, 4893 const struct sctp_association *asoc, 4894 const union sctp_subtype type, 4895 void *arg, 4896 struct sctp_cmd_seq *commands) 4897 { 4898 static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:"; 4899 4900 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4901 sizeof(err_str)); 4902 } 4903 4904 /* Handle protocol violation of an invalid chunk bundling. For example, 4905 * when we have an association and we receive bundled INIT-ACK, or 4906 * SHUTDOWN-COMPLETE, our peer is clearly violating the "MUST NOT bundle" 4907 * statement from the specs. Additionally, there might be an attacker 4908 * on the path and we may not want to continue this communication. 4909 */ 4910 static enum sctp_disposition sctp_sf_violation_chunk( 4911 struct net *net, 4912 const struct sctp_endpoint *ep, 4913 const struct sctp_association *asoc, 4914 const union sctp_subtype type, 4915 void *arg, 4916 struct sctp_cmd_seq *commands) 4917 { 4918 static const char err_str[] = "The following chunk violates protocol:"; 4919 4920 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4921 sizeof(err_str)); 4922 } 4923 /*************************************************************************** 4924 * These are the state functions for handling primitive (Section 10) events. 4925 ***************************************************************************/ 4926 /* 4927 * sctp_sf_do_prm_asoc 4928 * 4929 * Section: 10.1 ULP-to-SCTP 4930 * B) Associate 4931 * 4932 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 4933 * outbound stream count) 4934 * -> association id [,destination transport addr list] [,outbound stream 4935 * count] 4936 * 4937 * This primitive allows the upper layer to initiate an association to a 4938 * specific peer endpoint. 4939 * 4940 * The peer endpoint shall be specified by one of the transport addresses 4941 * which defines the endpoint (see Section 1.4). If the local SCTP 4942 * instance has not been initialized, the ASSOCIATE is considered an 4943 * error. 4944 * [This is not relevant for the kernel implementation since we do all 4945 * initialization at boot time. It we hadn't initialized we wouldn't 4946 * get anywhere near this code.] 4947 * 4948 * An association id, which is a local handle to the SCTP association, 4949 * will be returned on successful establishment of the association. If 4950 * SCTP is not able to open an SCTP association with the peer endpoint, 4951 * an error is returned. 4952 * [In the kernel implementation, the struct sctp_association needs to 4953 * be created BEFORE causing this primitive to run.] 4954 * 4955 * Other association parameters may be returned, including the 4956 * complete destination transport addresses of the peer as well as the 4957 * outbound stream count of the local endpoint. One of the transport 4958 * address from the returned destination addresses will be selected by 4959 * the local endpoint as default primary path for sending SCTP packets 4960 * to this peer. The returned "destination transport addr list" can 4961 * be used by the ULP to change the default primary path or to force 4962 * sending a packet to a specific transport address. [All of this 4963 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 4964 * function.] 4965 * 4966 * Mandatory attributes: 4967 * 4968 * o local SCTP instance name - obtained from the INITIALIZE operation. 4969 * [This is the argument asoc.] 4970 * o destination transport addr - specified as one of the transport 4971 * addresses of the peer endpoint with which the association is to be 4972 * established. 4973 * [This is asoc->peer.active_path.] 4974 * o outbound stream count - the number of outbound streams the ULP 4975 * would like to open towards this peer endpoint. 4976 * [BUG: This is not currently implemented.] 4977 * Optional attributes: 4978 * 4979 * None. 4980 * 4981 * The return value is a disposition. 4982 */ 4983 enum sctp_disposition sctp_sf_do_prm_asoc(struct net *net, 4984 const struct sctp_endpoint *ep, 4985 const struct sctp_association *asoc, 4986 const union sctp_subtype type, 4987 void *arg, 4988 struct sctp_cmd_seq *commands) 4989 { 4990 struct sctp_association *my_asoc; 4991 struct sctp_chunk *repl; 4992 4993 /* The comment below says that we enter COOKIE-WAIT AFTER 4994 * sending the INIT, but that doesn't actually work in our 4995 * implementation... 4996 */ 4997 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4998 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 4999 5000 /* RFC 2960 5.1 Normal Establishment of an Association 5001 * 5002 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 5003 * must provide its Verification Tag (Tag_A) in the Initiate 5004 * Tag field. Tag_A SHOULD be a random number in the range of 5005 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 5006 */ 5007 5008 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 5009 if (!repl) 5010 goto nomem; 5011 5012 /* Choose transport for INIT. */ 5013 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5014 SCTP_CHUNK(repl)); 5015 5016 /* Cast away the const modifier, as we want to just 5017 * rerun it through as a sideffect. 5018 */ 5019 my_asoc = (struct sctp_association *)asoc; 5020 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc)); 5021 5022 /* After sending the INIT, "A" starts the T1-init timer and 5023 * enters the COOKIE-WAIT state. 5024 */ 5025 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5026 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5027 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5028 return SCTP_DISPOSITION_CONSUME; 5029 5030 nomem: 5031 return SCTP_DISPOSITION_NOMEM; 5032 } 5033 5034 /* 5035 * Process the SEND primitive. 5036 * 5037 * Section: 10.1 ULP-to-SCTP 5038 * E) Send 5039 * 5040 * Format: SEND(association id, buffer address, byte count [,context] 5041 * [,stream id] [,life time] [,destination transport address] 5042 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 5043 * -> result 5044 * 5045 * This is the main method to send user data via SCTP. 5046 * 5047 * Mandatory attributes: 5048 * 5049 * o association id - local handle to the SCTP association 5050 * 5051 * o buffer address - the location where the user message to be 5052 * transmitted is stored; 5053 * 5054 * o byte count - The size of the user data in number of bytes; 5055 * 5056 * Optional attributes: 5057 * 5058 * o context - an optional 32 bit integer that will be carried in the 5059 * sending failure notification to the ULP if the transportation of 5060 * this User Message fails. 5061 * 5062 * o stream id - to indicate which stream to send the data on. If not 5063 * specified, stream 0 will be used. 5064 * 5065 * o life time - specifies the life time of the user data. The user data 5066 * will not be sent by SCTP after the life time expires. This 5067 * parameter can be used to avoid efforts to transmit stale 5068 * user messages. SCTP notifies the ULP if the data cannot be 5069 * initiated to transport (i.e. sent to the destination via SCTP's 5070 * send primitive) within the life time variable. However, the 5071 * user data will be transmitted if SCTP has attempted to transmit a 5072 * chunk before the life time expired. 5073 * 5074 * o destination transport address - specified as one of the destination 5075 * transport addresses of the peer endpoint to which this packet 5076 * should be sent. Whenever possible, SCTP should use this destination 5077 * transport address for sending the packets, instead of the current 5078 * primary path. 5079 * 5080 * o unorder flag - this flag, if present, indicates that the user 5081 * would like the data delivered in an unordered fashion to the peer 5082 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 5083 * message). 5084 * 5085 * o no-bundle flag - instructs SCTP not to bundle this user data with 5086 * other outbound DATA chunks. SCTP MAY still bundle even when 5087 * this flag is present, when faced with network congestion. 5088 * 5089 * o payload protocol-id - A 32 bit unsigned integer that is to be 5090 * passed to the peer indicating the type of payload protocol data 5091 * being transmitted. This value is passed as opaque data by SCTP. 5092 * 5093 * The return value is the disposition. 5094 */ 5095 enum sctp_disposition sctp_sf_do_prm_send(struct net *net, 5096 const struct sctp_endpoint *ep, 5097 const struct sctp_association *asoc, 5098 const union sctp_subtype type, 5099 void *arg, 5100 struct sctp_cmd_seq *commands) 5101 { 5102 struct sctp_datamsg *msg = arg; 5103 5104 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg)); 5105 return SCTP_DISPOSITION_CONSUME; 5106 } 5107 5108 /* 5109 * Process the SHUTDOWN primitive. 5110 * 5111 * Section: 10.1: 5112 * C) Shutdown 5113 * 5114 * Format: SHUTDOWN(association id) 5115 * -> result 5116 * 5117 * Gracefully closes an association. Any locally queued user data 5118 * will be delivered to the peer. The association will be terminated only 5119 * after the peer acknowledges all the SCTP packets sent. A success code 5120 * will be returned on successful termination of the association. If 5121 * attempting to terminate the association results in a failure, an error 5122 * code shall be returned. 5123 * 5124 * Mandatory attributes: 5125 * 5126 * o association id - local handle to the SCTP association 5127 * 5128 * Optional attributes: 5129 * 5130 * None. 5131 * 5132 * The return value is the disposition. 5133 */ 5134 enum sctp_disposition sctp_sf_do_9_2_prm_shutdown( 5135 struct net *net, 5136 const struct sctp_endpoint *ep, 5137 const struct sctp_association *asoc, 5138 const union sctp_subtype type, 5139 void *arg, 5140 struct sctp_cmd_seq *commands) 5141 { 5142 enum sctp_disposition disposition; 5143 5144 /* From 9.2 Shutdown of an Association 5145 * Upon receipt of the SHUTDOWN primitive from its upper 5146 * layer, the endpoint enters SHUTDOWN-PENDING state and 5147 * remains there until all outstanding data has been 5148 * acknowledged by its peer. The endpoint accepts no new data 5149 * from its upper layer, but retransmits data to the far end 5150 * if necessary to fill gaps. 5151 */ 5152 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5153 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 5154 5155 disposition = SCTP_DISPOSITION_CONSUME; 5156 if (sctp_outq_is_empty(&asoc->outqueue)) { 5157 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 5158 arg, commands); 5159 } 5160 5161 return disposition; 5162 } 5163 5164 /* 5165 * Process the ABORT primitive. 5166 * 5167 * Section: 10.1: 5168 * C) Abort 5169 * 5170 * Format: Abort(association id [, cause code]) 5171 * -> result 5172 * 5173 * Ungracefully closes an association. Any locally queued user data 5174 * will be discarded and an ABORT chunk is sent to the peer. A success code 5175 * will be returned on successful abortion of the association. If 5176 * attempting to abort the association results in a failure, an error 5177 * code shall be returned. 5178 * 5179 * Mandatory attributes: 5180 * 5181 * o association id - local handle to the SCTP association 5182 * 5183 * Optional attributes: 5184 * 5185 * o cause code - reason of the abort to be passed to the peer 5186 * 5187 * None. 5188 * 5189 * The return value is the disposition. 5190 */ 5191 enum sctp_disposition sctp_sf_do_9_1_prm_abort( 5192 struct net *net, 5193 const struct sctp_endpoint *ep, 5194 const struct sctp_association *asoc, 5195 const union sctp_subtype type, 5196 void *arg, 5197 struct sctp_cmd_seq *commands) 5198 { 5199 /* From 9.1 Abort of an Association 5200 * Upon receipt of the ABORT primitive from its upper 5201 * layer, the endpoint enters CLOSED state and 5202 * discard all outstanding data has been 5203 * acknowledged by its peer. The endpoint accepts no new data 5204 * from its upper layer, but retransmits data to the far end 5205 * if necessary to fill gaps. 5206 */ 5207 struct sctp_chunk *abort = arg; 5208 5209 if (abort) 5210 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 5211 5212 /* Even if we can't send the ABORT due to low memory delete the 5213 * TCB. This is a departure from our typical NOMEM handling. 5214 */ 5215 5216 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5217 SCTP_ERROR(ECONNABORTED)); 5218 /* Delete the established association. */ 5219 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5220 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 5221 5222 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5223 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5224 5225 return SCTP_DISPOSITION_ABORT; 5226 } 5227 5228 /* We tried an illegal operation on an association which is closed. */ 5229 enum sctp_disposition sctp_sf_error_closed(struct net *net, 5230 const struct sctp_endpoint *ep, 5231 const struct sctp_association *asoc, 5232 const union sctp_subtype type, 5233 void *arg, 5234 struct sctp_cmd_seq *commands) 5235 { 5236 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 5237 return SCTP_DISPOSITION_CONSUME; 5238 } 5239 5240 /* We tried an illegal operation on an association which is shutting 5241 * down. 5242 */ 5243 enum sctp_disposition sctp_sf_error_shutdown( 5244 struct net *net, 5245 const struct sctp_endpoint *ep, 5246 const struct sctp_association *asoc, 5247 const union sctp_subtype type, 5248 void *arg, 5249 struct sctp_cmd_seq *commands) 5250 { 5251 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, 5252 SCTP_ERROR(-ESHUTDOWN)); 5253 return SCTP_DISPOSITION_CONSUME; 5254 } 5255 5256 /* 5257 * sctp_cookie_wait_prm_shutdown 5258 * 5259 * Section: 4 Note: 2 5260 * Verification Tag: 5261 * Inputs 5262 * (endpoint, asoc) 5263 * 5264 * The RFC does not explicitly address this issue, but is the route through the 5265 * state table when someone issues a shutdown while in COOKIE_WAIT state. 5266 * 5267 * Outputs 5268 * (timers) 5269 */ 5270 enum sctp_disposition sctp_sf_cookie_wait_prm_shutdown( 5271 struct net *net, 5272 const struct sctp_endpoint *ep, 5273 const struct sctp_association *asoc, 5274 const union sctp_subtype type, 5275 void *arg, 5276 struct sctp_cmd_seq *commands) 5277 { 5278 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5279 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5280 5281 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5282 SCTP_STATE(SCTP_STATE_CLOSED)); 5283 5284 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 5285 5286 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 5287 5288 return SCTP_DISPOSITION_DELETE_TCB; 5289 } 5290 5291 /* 5292 * sctp_cookie_echoed_prm_shutdown 5293 * 5294 * Section: 4 Note: 2 5295 * Verification Tag: 5296 * Inputs 5297 * (endpoint, asoc) 5298 * 5299 * The RFC does not explicitly address this issue, but is the route through the 5300 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 5301 * 5302 * Outputs 5303 * (timers) 5304 */ 5305 enum sctp_disposition sctp_sf_cookie_echoed_prm_shutdown( 5306 struct net *net, 5307 const struct sctp_endpoint *ep, 5308 const struct sctp_association *asoc, 5309 const union sctp_subtype type, 5310 void *arg, 5311 struct sctp_cmd_seq *commands) 5312 { 5313 /* There is a single T1 timer, so we should be able to use 5314 * common function with the COOKIE-WAIT state. 5315 */ 5316 return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands); 5317 } 5318 5319 /* 5320 * sctp_sf_cookie_wait_prm_abort 5321 * 5322 * Section: 4 Note: 2 5323 * Verification Tag: 5324 * Inputs 5325 * (endpoint, asoc) 5326 * 5327 * The RFC does not explicitly address this issue, but is the route through the 5328 * state table when someone issues an abort while in COOKIE_WAIT state. 5329 * 5330 * Outputs 5331 * (timers) 5332 */ 5333 enum sctp_disposition sctp_sf_cookie_wait_prm_abort( 5334 struct net *net, 5335 const struct sctp_endpoint *ep, 5336 const struct sctp_association *asoc, 5337 const union sctp_subtype type, 5338 void *arg, 5339 struct sctp_cmd_seq *commands) 5340 { 5341 struct sctp_chunk *abort = arg; 5342 5343 /* Stop T1-init timer */ 5344 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5345 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5346 5347 if (abort) 5348 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 5349 5350 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5351 SCTP_STATE(SCTP_STATE_CLOSED)); 5352 5353 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5354 5355 /* Even if we can't send the ABORT due to low memory delete the 5356 * TCB. This is a departure from our typical NOMEM handling. 5357 */ 5358 5359 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5360 SCTP_ERROR(ECONNREFUSED)); 5361 /* Delete the established association. */ 5362 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5363 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 5364 5365 return SCTP_DISPOSITION_ABORT; 5366 } 5367 5368 /* 5369 * sctp_sf_cookie_echoed_prm_abort 5370 * 5371 * Section: 4 Note: 3 5372 * Verification Tag: 5373 * Inputs 5374 * (endpoint, asoc) 5375 * 5376 * The RFC does not explcitly address this issue, but is the route through the 5377 * state table when someone issues an abort while in COOKIE_ECHOED state. 5378 * 5379 * Outputs 5380 * (timers) 5381 */ 5382 enum sctp_disposition sctp_sf_cookie_echoed_prm_abort( 5383 struct net *net, 5384 const struct sctp_endpoint *ep, 5385 const struct sctp_association *asoc, 5386 const union sctp_subtype type, 5387 void *arg, 5388 struct sctp_cmd_seq *commands) 5389 { 5390 /* There is a single T1 timer, so we should be able to use 5391 * common function with the COOKIE-WAIT state. 5392 */ 5393 return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands); 5394 } 5395 5396 /* 5397 * sctp_sf_shutdown_pending_prm_abort 5398 * 5399 * Inputs 5400 * (endpoint, asoc) 5401 * 5402 * The RFC does not explicitly address this issue, but is the route through the 5403 * state table when someone issues an abort while in SHUTDOWN-PENDING state. 5404 * 5405 * Outputs 5406 * (timers) 5407 */ 5408 enum sctp_disposition sctp_sf_shutdown_pending_prm_abort( 5409 struct net *net, 5410 const struct sctp_endpoint *ep, 5411 const struct sctp_association *asoc, 5412 const union sctp_subtype type, 5413 void *arg, 5414 struct sctp_cmd_seq *commands) 5415 { 5416 /* Stop the T5-shutdown guard timer. */ 5417 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5418 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5419 5420 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5421 } 5422 5423 /* 5424 * sctp_sf_shutdown_sent_prm_abort 5425 * 5426 * Inputs 5427 * (endpoint, asoc) 5428 * 5429 * The RFC does not explicitly address this issue, but is the route through the 5430 * state table when someone issues an abort while in SHUTDOWN-SENT state. 5431 * 5432 * Outputs 5433 * (timers) 5434 */ 5435 enum sctp_disposition sctp_sf_shutdown_sent_prm_abort( 5436 struct net *net, 5437 const struct sctp_endpoint *ep, 5438 const struct sctp_association *asoc, 5439 const union sctp_subtype type, 5440 void *arg, 5441 struct sctp_cmd_seq *commands) 5442 { 5443 /* Stop the T2-shutdown timer. */ 5444 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5445 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5446 5447 /* Stop the T5-shutdown guard timer. */ 5448 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5449 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5450 5451 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5452 } 5453 5454 /* 5455 * sctp_sf_cookie_echoed_prm_abort 5456 * 5457 * Inputs 5458 * (endpoint, asoc) 5459 * 5460 * The RFC does not explcitly address this issue, but is the route through the 5461 * state table when someone issues an abort while in COOKIE_ECHOED state. 5462 * 5463 * Outputs 5464 * (timers) 5465 */ 5466 enum sctp_disposition sctp_sf_shutdown_ack_sent_prm_abort( 5467 struct net *net, 5468 const struct sctp_endpoint *ep, 5469 const struct sctp_association *asoc, 5470 const union sctp_subtype type, 5471 void *arg, 5472 struct sctp_cmd_seq *commands) 5473 { 5474 /* The same T2 timer, so we should be able to use 5475 * common function with the SHUTDOWN-SENT state. 5476 */ 5477 return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands); 5478 } 5479 5480 /* 5481 * Process the REQUESTHEARTBEAT primitive 5482 * 5483 * 10.1 ULP-to-SCTP 5484 * J) Request Heartbeat 5485 * 5486 * Format: REQUESTHEARTBEAT(association id, destination transport address) 5487 * 5488 * -> result 5489 * 5490 * Instructs the local endpoint to perform a HeartBeat on the specified 5491 * destination transport address of the given association. The returned 5492 * result should indicate whether the transmission of the HEARTBEAT 5493 * chunk to the destination address is successful. 5494 * 5495 * Mandatory attributes: 5496 * 5497 * o association id - local handle to the SCTP association 5498 * 5499 * o destination transport address - the transport address of the 5500 * association on which a heartbeat should be issued. 5501 */ 5502 enum sctp_disposition sctp_sf_do_prm_requestheartbeat( 5503 struct net *net, 5504 const struct sctp_endpoint *ep, 5505 const struct sctp_association *asoc, 5506 const union sctp_subtype type, 5507 void *arg, 5508 struct sctp_cmd_seq *commands) 5509 { 5510 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type, 5511 (struct sctp_transport *)arg, commands)) 5512 return SCTP_DISPOSITION_NOMEM; 5513 5514 /* 5515 * RFC 2960 (bis), section 8.3 5516 * 5517 * D) Request an on-demand HEARTBEAT on a specific destination 5518 * transport address of a given association. 5519 * 5520 * The endpoint should increment the respective error counter of 5521 * the destination transport address each time a HEARTBEAT is sent 5522 * to that address and not acknowledged within one RTO. 5523 * 5524 */ 5525 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 5526 SCTP_TRANSPORT(arg)); 5527 return SCTP_DISPOSITION_CONSUME; 5528 } 5529 5530 /* 5531 * ADDIP Section 4.1 ASCONF Chunk Procedures 5532 * When an endpoint has an ASCONF signaled change to be sent to the 5533 * remote endpoint it should do A1 to A9 5534 */ 5535 enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net, 5536 const struct sctp_endpoint *ep, 5537 const struct sctp_association *asoc, 5538 const union sctp_subtype type, 5539 void *arg, 5540 struct sctp_cmd_seq *commands) 5541 { 5542 struct sctp_chunk *chunk = arg; 5543 5544 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5545 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5546 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5547 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5548 return SCTP_DISPOSITION_CONSUME; 5549 } 5550 5551 /* RE-CONFIG Section 5.1 RECONF Chunk Procedures */ 5552 enum sctp_disposition sctp_sf_do_prm_reconf(struct net *net, 5553 const struct sctp_endpoint *ep, 5554 const struct sctp_association *asoc, 5555 const union sctp_subtype type, 5556 void *arg, 5557 struct sctp_cmd_seq *commands) 5558 { 5559 struct sctp_chunk *chunk = arg; 5560 5561 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5562 return SCTP_DISPOSITION_CONSUME; 5563 } 5564 5565 /* 5566 * Ignore the primitive event 5567 * 5568 * The return value is the disposition of the primitive. 5569 */ 5570 enum sctp_disposition sctp_sf_ignore_primitive( 5571 struct net *net, 5572 const struct sctp_endpoint *ep, 5573 const struct sctp_association *asoc, 5574 const union sctp_subtype type, 5575 void *arg, 5576 struct sctp_cmd_seq *commands) 5577 { 5578 pr_debug("%s: primitive type:%d is ignored\n", __func__, 5579 type.primitive); 5580 5581 return SCTP_DISPOSITION_DISCARD; 5582 } 5583 5584 /*************************************************************************** 5585 * These are the state functions for the OTHER events. 5586 ***************************************************************************/ 5587 5588 /* 5589 * When the SCTP stack has no more user data to send or retransmit, this 5590 * notification is given to the user. Also, at the time when a user app 5591 * subscribes to this event, if there is no data to be sent or 5592 * retransmit, the stack will immediately send up this notification. 5593 */ 5594 enum sctp_disposition sctp_sf_do_no_pending_tsn( 5595 struct net *net, 5596 const struct sctp_endpoint *ep, 5597 const struct sctp_association *asoc, 5598 const union sctp_subtype type, 5599 void *arg, 5600 struct sctp_cmd_seq *commands) 5601 { 5602 struct sctp_ulpevent *event; 5603 5604 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC); 5605 if (!event) 5606 return SCTP_DISPOSITION_NOMEM; 5607 5608 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event)); 5609 5610 return SCTP_DISPOSITION_CONSUME; 5611 } 5612 5613 /* 5614 * Start the shutdown negotiation. 5615 * 5616 * From Section 9.2: 5617 * Once all its outstanding data has been acknowledged, the endpoint 5618 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 5619 * TSN Ack field the last sequential TSN it has received from the peer. 5620 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 5621 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 5622 * with the updated last sequential TSN received from its peer. 5623 * 5624 * The return value is the disposition. 5625 */ 5626 enum sctp_disposition sctp_sf_do_9_2_start_shutdown( 5627 struct net *net, 5628 const struct sctp_endpoint *ep, 5629 const struct sctp_association *asoc, 5630 const union sctp_subtype type, 5631 void *arg, 5632 struct sctp_cmd_seq *commands) 5633 { 5634 struct sctp_chunk *reply; 5635 5636 /* Once all its outstanding data has been acknowledged, the 5637 * endpoint shall send a SHUTDOWN chunk to its peer including 5638 * in the Cumulative TSN Ack field the last sequential TSN it 5639 * has received from the peer. 5640 */ 5641 reply = sctp_make_shutdown(asoc, arg); 5642 if (!reply) 5643 goto nomem; 5644 5645 /* Set the transport for the SHUTDOWN chunk and the timeout for the 5646 * T2-shutdown timer. 5647 */ 5648 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5649 5650 /* It shall then start the T2-shutdown timer */ 5651 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5652 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5653 5654 /* RFC 4960 Section 9.2 5655 * The sender of the SHUTDOWN MAY also start an overall guard timer 5656 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5657 */ 5658 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5659 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5660 5661 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5662 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5663 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5664 5665 /* and enter the SHUTDOWN-SENT state. */ 5666 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5667 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 5668 5669 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5670 * 5671 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5672 * or SHUTDOWN-ACK. 5673 */ 5674 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5675 5676 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5677 5678 return SCTP_DISPOSITION_CONSUME; 5679 5680 nomem: 5681 return SCTP_DISPOSITION_NOMEM; 5682 } 5683 5684 /* 5685 * Generate a SHUTDOWN ACK now that everything is SACK'd. 5686 * 5687 * From Section 9.2: 5688 * 5689 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5690 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 5691 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 5692 * endpoint must re-send the SHUTDOWN ACK. 5693 * 5694 * The return value is the disposition. 5695 */ 5696 enum sctp_disposition sctp_sf_do_9_2_shutdown_ack( 5697 struct net *net, 5698 const struct sctp_endpoint *ep, 5699 const struct sctp_association *asoc, 5700 const union sctp_subtype type, 5701 void *arg, 5702 struct sctp_cmd_seq *commands) 5703 { 5704 struct sctp_chunk *chunk = arg; 5705 struct sctp_chunk *reply; 5706 5707 /* There are 2 ways of getting here: 5708 * 1) called in response to a SHUTDOWN chunk 5709 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 5710 * 5711 * For the case (2), the arg parameter is set to NULL. We need 5712 * to check that we have a chunk before accessing it's fields. 5713 */ 5714 if (chunk) { 5715 if (!sctp_vtag_verify(chunk, asoc)) 5716 return sctp_sf_pdiscard(net, ep, asoc, type, arg, 5717 commands); 5718 5719 /* Make sure that the SHUTDOWN chunk has a valid length. */ 5720 if (!sctp_chunk_length_valid( 5721 chunk, sizeof(struct sctp_shutdown_chunk))) 5722 return sctp_sf_violation_chunklen(net, ep, asoc, type, 5723 arg, commands); 5724 } 5725 5726 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5727 * shall send a SHUTDOWN ACK ... 5728 */ 5729 reply = sctp_make_shutdown_ack(asoc, chunk); 5730 if (!reply) 5731 goto nomem; 5732 5733 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 5734 * the T2-shutdown timer. 5735 */ 5736 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5737 5738 /* and start/restart a T2-shutdown timer of its own, */ 5739 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5740 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5741 5742 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5743 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5744 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5745 5746 /* Enter the SHUTDOWN-ACK-SENT state. */ 5747 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5748 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 5749 5750 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5751 * 5752 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5753 * or SHUTDOWN-ACK. 5754 */ 5755 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5756 5757 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5758 5759 return SCTP_DISPOSITION_CONSUME; 5760 5761 nomem: 5762 return SCTP_DISPOSITION_NOMEM; 5763 } 5764 5765 /* 5766 * Ignore the event defined as other 5767 * 5768 * The return value is the disposition of the event. 5769 */ 5770 enum sctp_disposition sctp_sf_ignore_other(struct net *net, 5771 const struct sctp_endpoint *ep, 5772 const struct sctp_association *asoc, 5773 const union sctp_subtype type, 5774 void *arg, 5775 struct sctp_cmd_seq *commands) 5776 { 5777 pr_debug("%s: the event other type:%d is ignored\n", 5778 __func__, type.other); 5779 5780 return SCTP_DISPOSITION_DISCARD; 5781 } 5782 5783 /************************************************************ 5784 * These are the state functions for handling timeout events. 5785 ************************************************************/ 5786 5787 /* 5788 * RTX Timeout 5789 * 5790 * Section: 6.3.3 Handle T3-rtx Expiration 5791 * 5792 * Whenever the retransmission timer T3-rtx expires for a destination 5793 * address, do the following: 5794 * [See below] 5795 * 5796 * The return value is the disposition of the chunk. 5797 */ 5798 enum sctp_disposition sctp_sf_do_6_3_3_rtx(struct net *net, 5799 const struct sctp_endpoint *ep, 5800 const struct sctp_association *asoc, 5801 const union sctp_subtype type, 5802 void *arg, 5803 struct sctp_cmd_seq *commands) 5804 { 5805 struct sctp_transport *transport = arg; 5806 5807 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS); 5808 5809 if (asoc->overall_error_count >= asoc->max_retrans) { 5810 if (asoc->peer.zero_window_announced && 5811 asoc->state == SCTP_STATE_SHUTDOWN_PENDING) { 5812 /* 5813 * We are here likely because the receiver had its rwnd 5814 * closed for a while and we have not been able to 5815 * transmit the locally queued data within the maximum 5816 * retransmission attempts limit. Start the T5 5817 * shutdown guard timer to give the receiver one last 5818 * chance and some additional time to recover before 5819 * aborting. 5820 */ 5821 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE, 5822 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5823 } else { 5824 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5825 SCTP_ERROR(ETIMEDOUT)); 5826 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5827 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5828 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5829 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5830 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5831 return SCTP_DISPOSITION_DELETE_TCB; 5832 } 5833 } 5834 5835 /* E1) For the destination address for which the timer 5836 * expires, adjust its ssthresh with rules defined in Section 5837 * 7.2.3 and set the cwnd <- MTU. 5838 */ 5839 5840 /* E2) For the destination address for which the timer 5841 * expires, set RTO <- RTO * 2 ("back off the timer"). The 5842 * maximum value discussed in rule C7 above (RTO.max) may be 5843 * used to provide an upper bound to this doubling operation. 5844 */ 5845 5846 /* E3) Determine how many of the earliest (i.e., lowest TSN) 5847 * outstanding DATA chunks for the address for which the 5848 * T3-rtx has expired will fit into a single packet, subject 5849 * to the MTU constraint for the path corresponding to the 5850 * destination transport address to which the retransmission 5851 * is being sent (this may be different from the address for 5852 * which the timer expires [see Section 6.4]). Call this 5853 * value K. Bundle and retransmit those K DATA chunks in a 5854 * single packet to the destination endpoint. 5855 * 5856 * Note: Any DATA chunks that were sent to the address for 5857 * which the T3-rtx timer expired but did not fit in one MTU 5858 * (rule E3 above), should be marked for retransmission and 5859 * sent as soon as cwnd allows (normally when a SACK arrives). 5860 */ 5861 5862 /* Do some failure management (Section 8.2). */ 5863 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5864 5865 /* NB: Rules E4 and F1 are implicit in R1. */ 5866 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 5867 5868 return SCTP_DISPOSITION_CONSUME; 5869 } 5870 5871 /* 5872 * Generate delayed SACK on timeout 5873 * 5874 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 5875 * 5876 * The guidelines on delayed acknowledgement algorithm specified in 5877 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 5878 * acknowledgement SHOULD be generated for at least every second packet 5879 * (not every second DATA chunk) received, and SHOULD be generated 5880 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 5881 * some situations it may be beneficial for an SCTP transmitter to be 5882 * more conservative than the algorithms detailed in this document 5883 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 5884 * the following algorithms allow. 5885 */ 5886 enum sctp_disposition sctp_sf_do_6_2_sack(struct net *net, 5887 const struct sctp_endpoint *ep, 5888 const struct sctp_association *asoc, 5889 const union sctp_subtype type, 5890 void *arg, 5891 struct sctp_cmd_seq *commands) 5892 { 5893 SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS); 5894 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 5895 return SCTP_DISPOSITION_CONSUME; 5896 } 5897 5898 /* 5899 * sctp_sf_t1_init_timer_expire 5900 * 5901 * Section: 4 Note: 2 5902 * Verification Tag: 5903 * Inputs 5904 * (endpoint, asoc) 5905 * 5906 * RFC 2960 Section 4 Notes 5907 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 5908 * and re-start the T1-init timer without changing state. This MUST 5909 * be repeated up to 'Max.Init.Retransmits' times. After that, the 5910 * endpoint MUST abort the initialization process and report the 5911 * error to SCTP user. 5912 * 5913 * Outputs 5914 * (timers, events) 5915 * 5916 */ 5917 enum sctp_disposition sctp_sf_t1_init_timer_expire( 5918 struct net *net, 5919 const struct sctp_endpoint *ep, 5920 const struct sctp_association *asoc, 5921 const union sctp_subtype type, 5922 void *arg, 5923 struct sctp_cmd_seq *commands) 5924 { 5925 int attempts = asoc->init_err_counter + 1; 5926 struct sctp_chunk *repl = NULL; 5927 struct sctp_bind_addr *bp; 5928 5929 pr_debug("%s: timer T1 expired (INIT)\n", __func__); 5930 5931 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS); 5932 5933 if (attempts <= asoc->max_init_attempts) { 5934 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 5935 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 5936 if (!repl) 5937 return SCTP_DISPOSITION_NOMEM; 5938 5939 /* Choose transport for INIT. */ 5940 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5941 SCTP_CHUNK(repl)); 5942 5943 /* Issue a sideeffect to do the needed accounting. */ 5944 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 5945 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5946 5947 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5948 } else { 5949 pr_debug("%s: giving up on INIT, attempts:%d " 5950 "max_init_attempts:%d\n", __func__, attempts, 5951 asoc->max_init_attempts); 5952 5953 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5954 SCTP_ERROR(ETIMEDOUT)); 5955 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5956 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5957 return SCTP_DISPOSITION_DELETE_TCB; 5958 } 5959 5960 return SCTP_DISPOSITION_CONSUME; 5961 } 5962 5963 /* 5964 * sctp_sf_t1_cookie_timer_expire 5965 * 5966 * Section: 4 Note: 2 5967 * Verification Tag: 5968 * Inputs 5969 * (endpoint, asoc) 5970 * 5971 * RFC 2960 Section 4 Notes 5972 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 5973 * COOKIE ECHO and re-start the T1-cookie timer without changing 5974 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 5975 * After that, the endpoint MUST abort the initialization process and 5976 * report the error to SCTP user. 5977 * 5978 * Outputs 5979 * (timers, events) 5980 * 5981 */ 5982 enum sctp_disposition sctp_sf_t1_cookie_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 int attempts = asoc->init_err_counter + 1; 5991 struct sctp_chunk *repl = NULL; 5992 5993 pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__); 5994 5995 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS); 5996 5997 if (attempts <= asoc->max_init_attempts) { 5998 repl = sctp_make_cookie_echo(asoc, NULL); 5999 if (!repl) 6000 return SCTP_DISPOSITION_NOMEM; 6001 6002 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 6003 SCTP_CHUNK(repl)); 6004 /* Issue a sideeffect to do the needed accounting. */ 6005 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 6006 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 6007 6008 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 6009 } else { 6010 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6011 SCTP_ERROR(ETIMEDOUT)); 6012 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 6013 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6014 return SCTP_DISPOSITION_DELETE_TCB; 6015 } 6016 6017 return SCTP_DISPOSITION_CONSUME; 6018 } 6019 6020 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 6021 * with the updated last sequential TSN received from its peer. 6022 * 6023 * An endpoint should limit the number of retransmission of the 6024 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 6025 * If this threshold is exceeded the endpoint should destroy the TCB and 6026 * MUST report the peer endpoint unreachable to the upper layer (and 6027 * thus the association enters the CLOSED state). The reception of any 6028 * packet from its peer (i.e. as the peer sends all of its queued DATA 6029 * chunks) should clear the endpoint's retransmission count and restart 6030 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 6031 * all of its queued DATA chunks that have not yet been sent. 6032 */ 6033 enum sctp_disposition sctp_sf_t2_timer_expire( 6034 struct net *net, 6035 const struct sctp_endpoint *ep, 6036 const struct sctp_association *asoc, 6037 const union sctp_subtype type, 6038 void *arg, 6039 struct sctp_cmd_seq *commands) 6040 { 6041 struct sctp_chunk *reply = NULL; 6042 6043 pr_debug("%s: timer T2 expired\n", __func__); 6044 6045 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS); 6046 6047 ((struct sctp_association *)asoc)->shutdown_retries++; 6048 6049 if (asoc->overall_error_count >= asoc->max_retrans) { 6050 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6051 SCTP_ERROR(ETIMEDOUT)); 6052 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 6053 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6054 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6055 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6056 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6057 return SCTP_DISPOSITION_DELETE_TCB; 6058 } 6059 6060 switch (asoc->state) { 6061 case SCTP_STATE_SHUTDOWN_SENT: 6062 reply = sctp_make_shutdown(asoc, NULL); 6063 break; 6064 6065 case SCTP_STATE_SHUTDOWN_ACK_SENT: 6066 reply = sctp_make_shutdown_ack(asoc, NULL); 6067 break; 6068 6069 default: 6070 BUG(); 6071 break; 6072 } 6073 6074 if (!reply) 6075 goto nomem; 6076 6077 /* Do some failure management (Section 8.2). 6078 * If we remove the transport an SHUTDOWN was last sent to, don't 6079 * do failure management. 6080 */ 6081 if (asoc->shutdown_last_sent_to) 6082 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 6083 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 6084 6085 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 6086 * the T2-shutdown timer. 6087 */ 6088 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 6089 6090 /* Restart the T2-shutdown timer. */ 6091 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 6092 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 6093 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 6094 return SCTP_DISPOSITION_CONSUME; 6095 6096 nomem: 6097 return SCTP_DISPOSITION_NOMEM; 6098 } 6099 6100 /* 6101 * ADDIP Section 4.1 ASCONF Chunk Procedures 6102 * If the T4 RTO timer expires the endpoint should do B1 to B5 6103 */ 6104 enum sctp_disposition sctp_sf_t4_timer_expire( 6105 struct net *net, 6106 const struct sctp_endpoint *ep, 6107 const struct sctp_association *asoc, 6108 const union sctp_subtype type, 6109 void *arg, 6110 struct sctp_cmd_seq *commands) 6111 { 6112 struct sctp_chunk *chunk = asoc->addip_last_asconf; 6113 struct sctp_transport *transport = chunk->transport; 6114 6115 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS); 6116 6117 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 6118 * detection on the appropriate destination address as defined in 6119 * RFC2960 [5] section 8.1 and 8.2. 6120 */ 6121 if (transport) 6122 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 6123 SCTP_TRANSPORT(transport)); 6124 6125 /* Reconfig T4 timer and transport. */ 6126 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 6127 6128 /* ADDIP 4.1 B2) Increment the association error counters and perform 6129 * endpoint failure detection on the association as defined in 6130 * RFC2960 [5] section 8.1 and 8.2. 6131 * association error counter is incremented in SCTP_CMD_STRIKE. 6132 */ 6133 if (asoc->overall_error_count >= asoc->max_retrans) { 6134 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 6135 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 6136 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6137 SCTP_ERROR(ETIMEDOUT)); 6138 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6139 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6140 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6141 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6142 return SCTP_DISPOSITION_ABORT; 6143 } 6144 6145 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 6146 * the ASCONF chunk was sent by doubling the RTO timer value. 6147 * This is done in SCTP_CMD_STRIKE. 6148 */ 6149 6150 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 6151 * choose an alternate destination address (please refer to RFC2960 6152 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 6153 * chunk, it MUST be the same (including its serial number) as the last 6154 * ASCONF sent. 6155 */ 6156 sctp_chunk_hold(asoc->addip_last_asconf); 6157 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6158 SCTP_CHUNK(asoc->addip_last_asconf)); 6159 6160 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 6161 * destination is selected, then the RTO used will be that of the new 6162 * destination address. 6163 */ 6164 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 6165 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 6166 6167 return SCTP_DISPOSITION_CONSUME; 6168 } 6169 6170 /* sctpimpguide-05 Section 2.12.2 6171 * The sender of the SHUTDOWN MAY also start an overall guard timer 6172 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 6173 * At the expiration of this timer the sender SHOULD abort the association 6174 * by sending an ABORT chunk. 6175 */ 6176 enum sctp_disposition sctp_sf_t5_timer_expire( 6177 struct net *net, 6178 const struct sctp_endpoint *ep, 6179 const struct sctp_association *asoc, 6180 const union sctp_subtype type, 6181 void *arg, 6182 struct sctp_cmd_seq *commands) 6183 { 6184 struct sctp_chunk *reply = NULL; 6185 6186 pr_debug("%s: timer T5 expired\n", __func__); 6187 6188 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS); 6189 6190 reply = sctp_make_abort(asoc, NULL, 0); 6191 if (!reply) 6192 goto nomem; 6193 6194 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 6195 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6196 SCTP_ERROR(ETIMEDOUT)); 6197 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6198 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6199 6200 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6201 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6202 6203 return SCTP_DISPOSITION_DELETE_TCB; 6204 nomem: 6205 return SCTP_DISPOSITION_NOMEM; 6206 } 6207 6208 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 6209 * the association is automatically closed by starting the shutdown process. 6210 * The work that needs to be done is same as when SHUTDOWN is initiated by 6211 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 6212 */ 6213 enum sctp_disposition sctp_sf_autoclose_timer_expire( 6214 struct net *net, 6215 const struct sctp_endpoint *ep, 6216 const struct sctp_association *asoc, 6217 const union sctp_subtype type, 6218 void *arg, 6219 struct sctp_cmd_seq *commands) 6220 { 6221 enum sctp_disposition disposition; 6222 6223 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS); 6224 6225 /* From 9.2 Shutdown of an Association 6226 * Upon receipt of the SHUTDOWN primitive from its upper 6227 * layer, the endpoint enters SHUTDOWN-PENDING state and 6228 * remains there until all outstanding data has been 6229 * acknowledged by its peer. The endpoint accepts no new data 6230 * from its upper layer, but retransmits data to the far end 6231 * if necessary to fill gaps. 6232 */ 6233 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 6234 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 6235 6236 disposition = SCTP_DISPOSITION_CONSUME; 6237 if (sctp_outq_is_empty(&asoc->outqueue)) { 6238 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 6239 NULL, commands); 6240 } 6241 6242 return disposition; 6243 } 6244 6245 /***************************************************************************** 6246 * These are sa state functions which could apply to all types of events. 6247 ****************************************************************************/ 6248 6249 /* 6250 * This table entry is not implemented. 6251 * 6252 * Inputs 6253 * (endpoint, asoc, chunk) 6254 * 6255 * The return value is the disposition of the chunk. 6256 */ 6257 enum sctp_disposition sctp_sf_not_impl(struct net *net, 6258 const struct sctp_endpoint *ep, 6259 const struct sctp_association *asoc, 6260 const union sctp_subtype type, 6261 void *arg, struct sctp_cmd_seq *commands) 6262 { 6263 return SCTP_DISPOSITION_NOT_IMPL; 6264 } 6265 6266 /* 6267 * This table entry represents a bug. 6268 * 6269 * Inputs 6270 * (endpoint, asoc, chunk) 6271 * 6272 * The return value is the disposition of the chunk. 6273 */ 6274 enum sctp_disposition sctp_sf_bug(struct net *net, 6275 const struct sctp_endpoint *ep, 6276 const struct sctp_association *asoc, 6277 const union sctp_subtype type, 6278 void *arg, struct sctp_cmd_seq *commands) 6279 { 6280 return SCTP_DISPOSITION_BUG; 6281 } 6282 6283 /* 6284 * This table entry represents the firing of a timer in the wrong state. 6285 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 6286 * when the association is in the wrong state. This event should 6287 * be ignored, so as to prevent any rearming of the timer. 6288 * 6289 * Inputs 6290 * (endpoint, asoc, chunk) 6291 * 6292 * The return value is the disposition of the chunk. 6293 */ 6294 enum sctp_disposition sctp_sf_timer_ignore(struct net *net, 6295 const struct sctp_endpoint *ep, 6296 const struct sctp_association *asoc, 6297 const union sctp_subtype type, 6298 void *arg, 6299 struct sctp_cmd_seq *commands) 6300 { 6301 pr_debug("%s: timer %d ignored\n", __func__, type.chunk); 6302 6303 return SCTP_DISPOSITION_CONSUME; 6304 } 6305 6306 /******************************************************************** 6307 * 2nd Level Abstractions 6308 ********************************************************************/ 6309 6310 /* Pull the SACK chunk based on the SACK header. */ 6311 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 6312 { 6313 struct sctp_sackhdr *sack; 6314 __u16 num_dup_tsns; 6315 unsigned int len; 6316 __u16 num_blocks; 6317 6318 /* Protect ourselves from reading too far into 6319 * the skb from a bogus sender. 6320 */ 6321 sack = (struct sctp_sackhdr *) chunk->skb->data; 6322 6323 num_blocks = ntohs(sack->num_gap_ack_blocks); 6324 num_dup_tsns = ntohs(sack->num_dup_tsns); 6325 len = sizeof(struct sctp_sackhdr); 6326 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 6327 if (len > chunk->skb->len) 6328 return NULL; 6329 6330 skb_pull(chunk->skb, len); 6331 6332 return sack; 6333 } 6334 6335 /* Create an ABORT packet to be sent as a response, with the specified 6336 * error causes. 6337 */ 6338 static struct sctp_packet *sctp_abort_pkt_new( 6339 struct net *net, 6340 const struct sctp_endpoint *ep, 6341 const struct sctp_association *asoc, 6342 struct sctp_chunk *chunk, 6343 const void *payload, size_t paylen) 6344 { 6345 struct sctp_packet *packet; 6346 struct sctp_chunk *abort; 6347 6348 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6349 6350 if (packet) { 6351 /* Make an ABORT. 6352 * The T bit will be set if the asoc is NULL. 6353 */ 6354 abort = sctp_make_abort(asoc, chunk, paylen); 6355 if (!abort) { 6356 sctp_ootb_pkt_free(packet); 6357 return NULL; 6358 } 6359 6360 /* Reflect vtag if T-Bit is set */ 6361 if (sctp_test_T_bit(abort)) 6362 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 6363 6364 /* Add specified error causes, i.e., payload, to the 6365 * end of the chunk. 6366 */ 6367 sctp_addto_chunk(abort, paylen, payload); 6368 6369 /* Set the skb to the belonging sock for accounting. */ 6370 abort->skb->sk = ep->base.sk; 6371 6372 sctp_packet_append_chunk(packet, abort); 6373 6374 } 6375 6376 return packet; 6377 } 6378 6379 /* Allocate a packet for responding in the OOTB conditions. */ 6380 static struct sctp_packet *sctp_ootb_pkt_new( 6381 struct net *net, 6382 const struct sctp_association *asoc, 6383 const struct sctp_chunk *chunk) 6384 { 6385 struct sctp_transport *transport; 6386 struct sctp_packet *packet; 6387 __u16 sport, dport; 6388 __u32 vtag; 6389 6390 /* Get the source and destination port from the inbound packet. */ 6391 sport = ntohs(chunk->sctp_hdr->dest); 6392 dport = ntohs(chunk->sctp_hdr->source); 6393 6394 /* The V-tag is going to be the same as the inbound packet if no 6395 * association exists, otherwise, use the peer's vtag. 6396 */ 6397 if (asoc) { 6398 /* Special case the INIT-ACK as there is no peer's vtag 6399 * yet. 6400 */ 6401 switch (chunk->chunk_hdr->type) { 6402 case SCTP_CID_INIT: 6403 case SCTP_CID_INIT_ACK: 6404 { 6405 struct sctp_initack_chunk *initack; 6406 6407 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr; 6408 vtag = ntohl(initack->init_hdr.init_tag); 6409 break; 6410 } 6411 default: 6412 vtag = asoc->peer.i.init_tag; 6413 break; 6414 } 6415 } else { 6416 /* Special case the INIT and stale COOKIE_ECHO as there is no 6417 * vtag yet. 6418 */ 6419 switch (chunk->chunk_hdr->type) { 6420 case SCTP_CID_INIT: 6421 { 6422 struct sctp_init_chunk *init; 6423 6424 init = (struct sctp_init_chunk *)chunk->chunk_hdr; 6425 vtag = ntohl(init->init_hdr.init_tag); 6426 break; 6427 } 6428 default: 6429 vtag = ntohl(chunk->sctp_hdr->vtag); 6430 break; 6431 } 6432 } 6433 6434 /* Make a transport for the bucket, Eliza... */ 6435 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC); 6436 if (!transport) 6437 goto nomem; 6438 6439 transport->encap_port = SCTP_INPUT_CB(chunk->skb)->encap_port; 6440 6441 /* Cache a route for the transport with the chunk's destination as 6442 * the source address. 6443 */ 6444 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 6445 sctp_sk(net->sctp.ctl_sock)); 6446 6447 packet = &transport->packet; 6448 sctp_packet_init(packet, transport, sport, dport); 6449 sctp_packet_config(packet, vtag, 0); 6450 6451 return packet; 6452 6453 nomem: 6454 return NULL; 6455 } 6456 6457 /* Free the packet allocated earlier for responding in the OOTB condition. */ 6458 void sctp_ootb_pkt_free(struct sctp_packet *packet) 6459 { 6460 sctp_transport_free(packet->transport); 6461 } 6462 6463 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 6464 static void sctp_send_stale_cookie_err(struct net *net, 6465 const struct sctp_endpoint *ep, 6466 const struct sctp_association *asoc, 6467 const struct sctp_chunk *chunk, 6468 struct sctp_cmd_seq *commands, 6469 struct sctp_chunk *err_chunk) 6470 { 6471 struct sctp_packet *packet; 6472 6473 if (err_chunk) { 6474 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6475 if (packet) { 6476 struct sctp_signed_cookie *cookie; 6477 6478 /* Override the OOTB vtag from the cookie. */ 6479 cookie = chunk->subh.cookie_hdr; 6480 packet->vtag = cookie->c.peer_vtag; 6481 6482 /* Set the skb to the belonging sock for accounting. */ 6483 err_chunk->skb->sk = ep->base.sk; 6484 sctp_packet_append_chunk(packet, err_chunk); 6485 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 6486 SCTP_PACKET(packet)); 6487 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 6488 } else 6489 sctp_chunk_free (err_chunk); 6490 } 6491 } 6492 6493 6494 /* Process a data chunk */ 6495 static int sctp_eat_data(const struct sctp_association *asoc, 6496 struct sctp_chunk *chunk, 6497 struct sctp_cmd_seq *commands) 6498 { 6499 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; 6500 struct sock *sk = asoc->base.sk; 6501 struct net *net = sock_net(sk); 6502 struct sctp_datahdr *data_hdr; 6503 struct sctp_chunk *err; 6504 enum sctp_verb deliver; 6505 size_t datalen; 6506 __u32 tsn; 6507 int tmp; 6508 6509 data_hdr = (struct sctp_datahdr *)chunk->skb->data; 6510 chunk->subh.data_hdr = data_hdr; 6511 skb_pull(chunk->skb, sctp_datahdr_len(&asoc->stream)); 6512 6513 tsn = ntohl(data_hdr->tsn); 6514 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 6515 6516 /* ASSERT: Now skb->data is really the user data. */ 6517 6518 /* Process ECN based congestion. 6519 * 6520 * Since the chunk structure is reused for all chunks within 6521 * a packet, we use ecn_ce_done to track if we've already 6522 * done CE processing for this packet. 6523 * 6524 * We need to do ECN processing even if we plan to discard the 6525 * chunk later. 6526 */ 6527 6528 if (asoc->peer.ecn_capable && !chunk->ecn_ce_done) { 6529 struct sctp_af *af = SCTP_INPUT_CB(chunk->skb)->af; 6530 chunk->ecn_ce_done = 1; 6531 6532 if (af->is_ce(sctp_gso_headskb(chunk->skb))) { 6533 /* Do real work as side effect. */ 6534 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 6535 SCTP_U32(tsn)); 6536 } 6537 } 6538 6539 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 6540 if (tmp < 0) { 6541 /* The TSN is too high--silently discard the chunk and 6542 * count on it getting retransmitted later. 6543 */ 6544 if (chunk->asoc) 6545 chunk->asoc->stats.outofseqtsns++; 6546 return SCTP_IERROR_HIGH_TSN; 6547 } else if (tmp > 0) { 6548 /* This is a duplicate. Record it. */ 6549 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 6550 return SCTP_IERROR_DUP_TSN; 6551 } 6552 6553 /* This is a new TSN. */ 6554 6555 /* Discard if there is no room in the receive window. 6556 * Actually, allow a little bit of overflow (up to a MTU). 6557 */ 6558 datalen = ntohs(chunk->chunk_hdr->length); 6559 datalen -= sctp_datachk_len(&asoc->stream); 6560 6561 deliver = SCTP_CMD_CHUNK_ULP; 6562 6563 /* Think about partial delivery. */ 6564 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 6565 6566 /* Even if we don't accept this chunk there is 6567 * memory pressure. 6568 */ 6569 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 6570 } 6571 6572 /* Spill over rwnd a little bit. Note: While allowed, this spill over 6573 * seems a bit troublesome in that frag_point varies based on 6574 * PMTU. In cases, such as loopback, this might be a rather 6575 * large spill over. 6576 */ 6577 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over || 6578 (datalen > asoc->rwnd + asoc->frag_point))) { 6579 6580 /* If this is the next TSN, consider reneging to make 6581 * room. Note: Playing nice with a confused sender. A 6582 * malicious sender can still eat up all our buffer 6583 * space and in the future we may want to detect and 6584 * do more drastic reneging. 6585 */ 6586 if (sctp_tsnmap_has_gap(map) && 6587 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6588 pr_debug("%s: reneging for tsn:%u\n", __func__, tsn); 6589 deliver = SCTP_CMD_RENEGE; 6590 } else { 6591 pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n", 6592 __func__, tsn, datalen, asoc->rwnd); 6593 6594 return SCTP_IERROR_IGNORE_TSN; 6595 } 6596 } 6597 6598 /* 6599 * Also try to renege to limit our memory usage in the event that 6600 * we are under memory pressure 6601 * If we can't renege, don't worry about it, the sk_rmem_schedule 6602 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our 6603 * memory usage too much 6604 */ 6605 if (sk_under_memory_pressure(sk)) { 6606 if (sctp_tsnmap_has_gap(map) && 6607 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6608 pr_debug("%s: under pressure, reneging for tsn:%u\n", 6609 __func__, tsn); 6610 deliver = SCTP_CMD_RENEGE; 6611 } 6612 } 6613 6614 /* 6615 * Section 3.3.10.9 No User Data (9) 6616 * 6617 * Cause of error 6618 * --------------- 6619 * No User Data: This error cause is returned to the originator of a 6620 * DATA chunk if a received DATA chunk has no user data. 6621 */ 6622 if (unlikely(0 == datalen)) { 6623 err = sctp_make_abort_no_data(asoc, chunk, tsn); 6624 if (err) { 6625 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6626 SCTP_CHUNK(err)); 6627 } 6628 /* We are going to ABORT, so we might as well stop 6629 * processing the rest of the chunks in the packet. 6630 */ 6631 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 6632 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6633 SCTP_ERROR(ECONNABORTED)); 6634 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6635 SCTP_PERR(SCTP_ERROR_NO_DATA)); 6636 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6637 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6638 return SCTP_IERROR_NO_DATA; 6639 } 6640 6641 chunk->data_accepted = 1; 6642 6643 /* Note: Some chunks may get overcounted (if we drop) or overcounted 6644 * if we renege and the chunk arrives again. 6645 */ 6646 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) { 6647 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS); 6648 if (chunk->asoc) 6649 chunk->asoc->stats.iuodchunks++; 6650 } else { 6651 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS); 6652 if (chunk->asoc) 6653 chunk->asoc->stats.iodchunks++; 6654 } 6655 6656 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 6657 * 6658 * If an endpoint receive a DATA chunk with an invalid stream 6659 * identifier, it shall acknowledge the reception of the DATA chunk 6660 * following the normal procedure, immediately send an ERROR chunk 6661 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 6662 * and discard the DATA chunk. 6663 */ 6664 if (ntohs(data_hdr->stream) >= asoc->stream.incnt) { 6665 /* Mark tsn as received even though we drop it */ 6666 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 6667 6668 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 6669 &data_hdr->stream, 6670 sizeof(data_hdr->stream), 6671 sizeof(u16)); 6672 if (err) 6673 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6674 SCTP_CHUNK(err)); 6675 return SCTP_IERROR_BAD_STREAM; 6676 } 6677 6678 /* Check to see if the SSN is possible for this TSN. 6679 * The biggest gap we can record is 4K wide. Since SSNs wrap 6680 * at an unsigned short, there is no way that an SSN can 6681 * wrap and for a valid TSN. We can simply check if the current 6682 * SSN is smaller then the next expected one. If it is, it wrapped 6683 * and is invalid. 6684 */ 6685 if (!asoc->stream.si->validate_data(chunk)) 6686 return SCTP_IERROR_PROTO_VIOLATION; 6687 6688 /* Send the data up to the user. Note: Schedule the 6689 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 6690 * chunk needs the updated rwnd. 6691 */ 6692 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 6693 6694 return SCTP_IERROR_NO_ERROR; 6695 } 6696