1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* SCTP kernel implementation 3 * (C) Copyright IBM Corp. 2001, 2004 4 * Copyright (c) 1999-2000 Cisco, Inc. 5 * Copyright (c) 1999-2001 Motorola, Inc. 6 * Copyright (c) 2001-2002 Intel Corp. 7 * Copyright (c) 2002 Nokia Corp. 8 * 9 * This is part of the SCTP Linux Kernel Implementation. 10 * 11 * These are the state functions for the state machine. 12 * 13 * Please send any bug reports or fixes you make to the 14 * email address(es): 15 * lksctp developers <linux-sctp@vger.kernel.org> 16 * 17 * Written or modified by: 18 * La Monte H.P. Yarroll <piggy@acm.org> 19 * Karl Knutson <karl@athena.chicago.il.us> 20 * Mathew Kotowsky <kotowsky@sctp.org> 21 * Sridhar Samudrala <samudrala@us.ibm.com> 22 * Jon Grimm <jgrimm@us.ibm.com> 23 * Hui Huang <hui.huang@nokia.com> 24 * Dajiang Zhang <dajiang.zhang@nokia.com> 25 * Daisy Chang <daisyc@us.ibm.com> 26 * Ardelle Fan <ardelle.fan@intel.com> 27 * Ryan Layer <rmlayer@us.ibm.com> 28 * Kevin Gao <kevin.gao@intel.com> 29 */ 30 31 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 32 33 #include <linux/types.h> 34 #include <linux/kernel.h> 35 #include <linux/ip.h> 36 #include <linux/ipv6.h> 37 #include <linux/net.h> 38 #include <linux/inet.h> 39 #include <linux/slab.h> 40 #include <net/sock.h> 41 #include <net/inet_ecn.h> 42 #include <linux/skbuff.h> 43 #include <net/sctp/sctp.h> 44 #include <net/sctp/sm.h> 45 #include <net/sctp/structs.h> 46 47 #define CREATE_TRACE_POINTS 48 #include <trace/events/sctp.h> 49 50 static struct sctp_packet *sctp_abort_pkt_new( 51 struct net *net, 52 const struct sctp_endpoint *ep, 53 const struct sctp_association *asoc, 54 struct sctp_chunk *chunk, 55 const void *payload, size_t paylen); 56 static int sctp_eat_data(const struct sctp_association *asoc, 57 struct sctp_chunk *chunk, 58 struct sctp_cmd_seq *commands); 59 static struct sctp_packet *sctp_ootb_pkt_new( 60 struct net *net, 61 const struct sctp_association *asoc, 62 const struct sctp_chunk *chunk); 63 static void sctp_send_stale_cookie_err(struct net *net, 64 const struct sctp_endpoint *ep, 65 const struct sctp_association *asoc, 66 const struct sctp_chunk *chunk, 67 struct sctp_cmd_seq *commands, 68 struct sctp_chunk *err_chunk); 69 static enum sctp_disposition sctp_sf_do_5_2_6_stale( 70 struct net *net, 71 const struct sctp_endpoint *ep, 72 const struct sctp_association *asoc, 73 const union sctp_subtype type, 74 void *arg, 75 struct sctp_cmd_seq *commands); 76 static enum sctp_disposition sctp_sf_shut_8_4_5( 77 struct net *net, 78 const struct sctp_endpoint *ep, 79 const struct sctp_association *asoc, 80 const union sctp_subtype type, 81 void *arg, 82 struct sctp_cmd_seq *commands); 83 static enum sctp_disposition sctp_sf_tabort_8_4_8( 84 struct net *net, 85 const struct sctp_endpoint *ep, 86 const struct sctp_association *asoc, 87 const union sctp_subtype type, 88 void *arg, 89 struct sctp_cmd_seq *commands); 90 static enum sctp_disposition sctp_sf_new_encap_port( 91 struct net *net, 92 const struct sctp_endpoint *ep, 93 const struct sctp_association *asoc, 94 const union sctp_subtype type, 95 void *arg, 96 struct sctp_cmd_seq *commands); 97 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk); 98 99 static enum sctp_disposition sctp_stop_t1_and_abort( 100 struct net *net, 101 struct sctp_cmd_seq *commands, 102 __be16 error, int sk_err, 103 const struct sctp_association *asoc, 104 struct sctp_transport *transport); 105 106 static enum sctp_disposition sctp_sf_abort_violation( 107 struct net *net, 108 const struct sctp_endpoint *ep, 109 const struct sctp_association *asoc, 110 void *arg, 111 struct sctp_cmd_seq *commands, 112 const __u8 *payload, 113 const size_t paylen); 114 115 static enum sctp_disposition sctp_sf_violation_chunklen( 116 struct net *net, 117 const struct sctp_endpoint *ep, 118 const struct sctp_association *asoc, 119 const union sctp_subtype type, 120 void *arg, 121 struct sctp_cmd_seq *commands); 122 123 static enum sctp_disposition sctp_sf_violation_paramlen( 124 struct net *net, 125 const struct sctp_endpoint *ep, 126 const struct sctp_association *asoc, 127 const union sctp_subtype type, 128 void *arg, void *ext, 129 struct sctp_cmd_seq *commands); 130 131 static enum sctp_disposition sctp_sf_violation_ctsn( 132 struct net *net, 133 const struct sctp_endpoint *ep, 134 const struct sctp_association *asoc, 135 const union sctp_subtype type, 136 void *arg, 137 struct sctp_cmd_seq *commands); 138 139 static enum sctp_disposition sctp_sf_violation_chunk( 140 struct net *net, 141 const struct sctp_endpoint *ep, 142 const struct sctp_association *asoc, 143 const union sctp_subtype type, 144 void *arg, 145 struct sctp_cmd_seq *commands); 146 147 static enum sctp_ierror sctp_sf_authenticate( 148 const struct sctp_association *asoc, 149 struct sctp_chunk *chunk); 150 151 static enum sctp_disposition __sctp_sf_do_9_1_abort( 152 struct net *net, 153 const struct sctp_endpoint *ep, 154 const struct sctp_association *asoc, 155 const union sctp_subtype type, 156 void *arg, 157 struct sctp_cmd_seq *commands); 158 159 /* Small helper function that checks if the chunk length 160 * is of the appropriate length. The 'required_length' argument 161 * is set to be the size of a specific chunk we are testing. 162 * Return Values: true = Valid length 163 * false = Invalid length 164 * 165 */ 166 static inline bool sctp_chunk_length_valid(struct sctp_chunk *chunk, 167 __u16 required_length) 168 { 169 __u16 chunk_length = ntohs(chunk->chunk_hdr->length); 170 171 /* Previously already marked? */ 172 if (unlikely(chunk->pdiscard)) 173 return false; 174 if (unlikely(chunk_length < required_length)) 175 return false; 176 177 return true; 178 } 179 180 /* Check for format error in an ABORT chunk */ 181 static inline bool sctp_err_chunk_valid(struct sctp_chunk *chunk) 182 { 183 struct sctp_errhdr *err; 184 185 sctp_walk_errors(err, chunk->chunk_hdr); 186 187 return (void *)err == (void *)chunk->chunk_end; 188 } 189 190 /********************************************************** 191 * These are the state functions for handling chunk events. 192 **********************************************************/ 193 194 /* 195 * Process the final SHUTDOWN COMPLETE. 196 * 197 * Section: 4 (C) (diagram), 9.2 198 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify 199 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be 200 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint 201 * should stop the T2-shutdown timer and remove all knowledge of the 202 * association (and thus the association enters the CLOSED state). 203 * 204 * Verification Tag: 8.5.1(C), sctpimpguide 2.41. 205 * C) Rules for packet carrying SHUTDOWN COMPLETE: 206 * ... 207 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet 208 * if the Verification Tag field of the packet matches its own tag and 209 * the T bit is not set 210 * OR 211 * it is set to its peer's tag and the T bit is set in the Chunk 212 * Flags. 213 * Otherwise, the receiver MUST silently discard the packet 214 * and take no further action. An endpoint MUST ignore the 215 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state. 216 * 217 * Inputs 218 * (endpoint, asoc, chunk) 219 * 220 * Outputs 221 * (asoc, reply_msg, msg_up, timers, counters) 222 * 223 * The return value is the disposition of the chunk. 224 */ 225 enum sctp_disposition sctp_sf_do_4_C(struct net *net, 226 const struct sctp_endpoint *ep, 227 const struct sctp_association *asoc, 228 const union sctp_subtype type, 229 void *arg, struct sctp_cmd_seq *commands) 230 { 231 struct sctp_chunk *chunk = arg; 232 struct sctp_ulpevent *ev; 233 234 if (!sctp_vtag_verify_either(chunk, asoc)) 235 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 236 237 /* RFC 2960 6.10 Bundling 238 * 239 * An endpoint MUST NOT bundle INIT, INIT ACK or 240 * SHUTDOWN COMPLETE with any other chunks. 241 */ 242 if (!chunk->singleton) 243 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 244 245 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */ 246 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 247 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 248 commands); 249 250 /* RFC 2960 10.2 SCTP-to-ULP 251 * 252 * H) SHUTDOWN COMPLETE notification 253 * 254 * When SCTP completes the shutdown procedures (section 9.2) this 255 * notification is passed to the upper layer. 256 */ 257 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 258 0, 0, 0, NULL, GFP_ATOMIC); 259 if (ev) 260 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 261 SCTP_ULPEVENT(ev)); 262 263 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint 264 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is 265 * not the chunk should be discarded. If the endpoint is in 266 * the SHUTDOWN-ACK-SENT state the endpoint should stop the 267 * T2-shutdown timer and remove all knowledge of the 268 * association (and thus the association enters the CLOSED 269 * state). 270 */ 271 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 272 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 273 274 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 275 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 276 277 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 278 SCTP_STATE(SCTP_STATE_CLOSED)); 279 280 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 281 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 282 283 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 284 285 return SCTP_DISPOSITION_DELETE_TCB; 286 } 287 288 /* 289 * Respond to a normal INIT chunk. 290 * We are the side that is being asked for an association. 291 * 292 * Section: 5.1 Normal Establishment of an Association, B 293 * B) "Z" shall respond immediately with an INIT ACK chunk. The 294 * destination IP address of the INIT ACK MUST be set to the source 295 * IP address of the INIT to which this INIT ACK is responding. In 296 * the response, besides filling in other parameters, "Z" must set the 297 * Verification Tag field to Tag_A, and also provide its own 298 * Verification Tag (Tag_Z) in the Initiate Tag field. 299 * 300 * Verification Tag: Must be 0. 301 * 302 * Inputs 303 * (endpoint, asoc, chunk) 304 * 305 * Outputs 306 * (asoc, reply_msg, msg_up, timers, counters) 307 * 308 * The return value is the disposition of the chunk. 309 */ 310 enum sctp_disposition sctp_sf_do_5_1B_init(struct net *net, 311 const struct sctp_endpoint *ep, 312 const struct sctp_association *asoc, 313 const union sctp_subtype type, 314 void *arg, 315 struct sctp_cmd_seq *commands) 316 { 317 struct sctp_chunk *chunk = arg, *repl, *err_chunk; 318 struct sctp_unrecognized_param *unk_param; 319 struct sctp_association *new_asoc; 320 struct sctp_packet *packet; 321 int len; 322 323 /* Update socket peer label if first association. */ 324 if (security_sctp_assoc_request((struct sctp_endpoint *)ep, 325 chunk->skb)) 326 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 327 328 /* 6.10 Bundling 329 * An endpoint MUST NOT bundle INIT, INIT ACK or 330 * SHUTDOWN COMPLETE with any other chunks. 331 * 332 * IG Section 2.11.2 333 * Furthermore, we require that the receiver of an INIT chunk MUST 334 * enforce these rules by silently discarding an arriving packet 335 * with an INIT chunk that is bundled with other chunks. 336 */ 337 if (!chunk->singleton) 338 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 339 340 /* If the packet is an OOTB packet which is temporarily on the 341 * control endpoint, respond with an ABORT. 342 */ 343 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 344 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 345 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 346 } 347 348 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 349 * Tag. 350 */ 351 if (chunk->sctp_hdr->vtag != 0) 352 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 353 354 /* Make sure that the INIT chunk has a valid length. 355 * Normally, this would cause an ABORT with a Protocol Violation 356 * error, but since we don't have an association, we'll 357 * just discard the packet. 358 */ 359 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk))) 360 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 361 362 /* If the INIT is coming toward a closing socket, we'll send back 363 * and ABORT. Essentially, this catches the race of INIT being 364 * backloged to the socket at the same time as the user issues close(). 365 * Since the socket and all its associations are going away, we 366 * can treat this OOTB 367 */ 368 if (sctp_sstate(ep->base.sk, CLOSING)) 369 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 370 371 /* Verify the INIT chunk before processing it. */ 372 err_chunk = NULL; 373 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 374 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 375 &err_chunk)) { 376 /* This chunk contains fatal error. It is to be discarded. 377 * Send an ABORT, with causes if there is any. 378 */ 379 if (err_chunk) { 380 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 381 (__u8 *)(err_chunk->chunk_hdr) + 382 sizeof(struct sctp_chunkhdr), 383 ntohs(err_chunk->chunk_hdr->length) - 384 sizeof(struct sctp_chunkhdr)); 385 386 sctp_chunk_free(err_chunk); 387 388 if (packet) { 389 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 390 SCTP_PACKET(packet)); 391 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 392 return SCTP_DISPOSITION_CONSUME; 393 } else { 394 return SCTP_DISPOSITION_NOMEM; 395 } 396 } else { 397 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 398 commands); 399 } 400 } 401 402 /* Grab the INIT header. */ 403 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 404 405 /* Tag the variable length parameters. */ 406 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 407 408 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 409 if (!new_asoc) 410 goto nomem; 411 412 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 413 sctp_scope(sctp_source(chunk)), 414 GFP_ATOMIC) < 0) 415 goto nomem_init; 416 417 /* The call, sctp_process_init(), can fail on memory allocation. */ 418 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 419 (struct sctp_init_chunk *)chunk->chunk_hdr, 420 GFP_ATOMIC)) 421 goto nomem_init; 422 423 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 424 425 /* If there are errors need to be reported for unknown parameters, 426 * make sure to reserve enough room in the INIT ACK for them. 427 */ 428 len = 0; 429 if (err_chunk) 430 len = ntohs(err_chunk->chunk_hdr->length) - 431 sizeof(struct sctp_chunkhdr); 432 433 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 434 if (!repl) 435 goto nomem_init; 436 437 /* If there are errors need to be reported for unknown parameters, 438 * include them in the outgoing INIT ACK as "Unrecognized parameter" 439 * parameter. 440 */ 441 if (err_chunk) { 442 /* Get the "Unrecognized parameter" parameter(s) out of the 443 * ERROR chunk generated by sctp_verify_init(). Since the 444 * error cause code for "unknown parameter" and the 445 * "Unrecognized parameter" type is the same, we can 446 * construct the parameters in INIT ACK by copying the 447 * ERROR causes over. 448 */ 449 unk_param = (struct sctp_unrecognized_param *) 450 ((__u8 *)(err_chunk->chunk_hdr) + 451 sizeof(struct sctp_chunkhdr)); 452 /* Replace the cause code with the "Unrecognized parameter" 453 * parameter type. 454 */ 455 sctp_addto_chunk(repl, len, unk_param); 456 sctp_chunk_free(err_chunk); 457 } 458 459 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 460 461 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 462 463 /* 464 * Note: After sending out INIT ACK with the State Cookie parameter, 465 * "Z" MUST NOT allocate any resources, nor keep any states for the 466 * new association. Otherwise, "Z" will be vulnerable to resource 467 * attacks. 468 */ 469 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 470 471 return SCTP_DISPOSITION_DELETE_TCB; 472 473 nomem_init: 474 sctp_association_free(new_asoc); 475 nomem: 476 if (err_chunk) 477 sctp_chunk_free(err_chunk); 478 return SCTP_DISPOSITION_NOMEM; 479 } 480 481 /* 482 * Respond to a normal INIT ACK chunk. 483 * We are the side that is initiating the association. 484 * 485 * Section: 5.1 Normal Establishment of an Association, C 486 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init 487 * timer and leave COOKIE-WAIT state. "A" shall then send the State 488 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start 489 * the T1-cookie timer, and enter the COOKIE-ECHOED state. 490 * 491 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound 492 * DATA chunks, but it MUST be the first chunk in the packet and 493 * until the COOKIE ACK is returned the sender MUST NOT send any 494 * other packets to the peer. 495 * 496 * Verification Tag: 3.3.3 497 * If the value of the Initiate Tag in a received INIT ACK chunk is 498 * found to be 0, the receiver MUST treat it as an error and close the 499 * association by transmitting an ABORT. 500 * 501 * Inputs 502 * (endpoint, asoc, chunk) 503 * 504 * Outputs 505 * (asoc, reply_msg, msg_up, timers, counters) 506 * 507 * The return value is the disposition of the chunk. 508 */ 509 enum sctp_disposition sctp_sf_do_5_1C_ack(struct net *net, 510 const struct sctp_endpoint *ep, 511 const struct sctp_association *asoc, 512 const union sctp_subtype type, 513 void *arg, 514 struct sctp_cmd_seq *commands) 515 { 516 struct sctp_init_chunk *initchunk; 517 struct sctp_chunk *chunk = arg; 518 struct sctp_chunk *err_chunk; 519 struct sctp_packet *packet; 520 521 if (!sctp_vtag_verify(chunk, asoc)) 522 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 523 524 /* 6.10 Bundling 525 * An endpoint MUST NOT bundle INIT, INIT ACK or 526 * SHUTDOWN COMPLETE with any other chunks. 527 */ 528 if (!chunk->singleton) 529 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 530 531 /* Make sure that the INIT-ACK chunk has a valid length */ 532 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_initack_chunk))) 533 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 534 commands); 535 /* Grab the INIT header. */ 536 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 537 538 /* Verify the INIT chunk before processing it. */ 539 err_chunk = NULL; 540 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 541 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 542 &err_chunk)) { 543 544 enum sctp_error error = SCTP_ERROR_NO_RESOURCE; 545 546 /* This chunk contains fatal error. It is to be discarded. 547 * Send an ABORT, with causes. If there are no causes, 548 * then there wasn't enough memory. Just terminate 549 * the association. 550 */ 551 if (err_chunk) { 552 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 553 (__u8 *)(err_chunk->chunk_hdr) + 554 sizeof(struct sctp_chunkhdr), 555 ntohs(err_chunk->chunk_hdr->length) - 556 sizeof(struct sctp_chunkhdr)); 557 558 sctp_chunk_free(err_chunk); 559 560 if (packet) { 561 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 562 SCTP_PACKET(packet)); 563 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 564 error = SCTP_ERROR_INV_PARAM; 565 } 566 } 567 568 /* SCTP-AUTH, Section 6.3: 569 * It should be noted that if the receiver wants to tear 570 * down an association in an authenticated way only, the 571 * handling of malformed packets should not result in 572 * tearing down the association. 573 * 574 * This means that if we only want to abort associations 575 * in an authenticated way (i.e AUTH+ABORT), then we 576 * can't destroy this association just because the packet 577 * was malformed. 578 */ 579 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 580 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 581 582 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 583 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, 584 asoc, chunk->transport); 585 } 586 587 /* Tag the variable length parameters. Note that we never 588 * convert the parameters in an INIT chunk. 589 */ 590 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 591 592 initchunk = (struct sctp_init_chunk *)chunk->chunk_hdr; 593 594 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT, 595 SCTP_PEER_INIT(initchunk)); 596 597 /* Reset init error count upon receipt of INIT-ACK. */ 598 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 599 600 /* 5.1 C) "A" shall stop the T1-init timer and leave 601 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie 602 * timer, and enter the COOKIE-ECHOED state. 603 */ 604 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 605 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 606 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 607 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 608 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 609 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED)); 610 611 /* SCTP-AUTH: generate the association shared keys so that 612 * we can potentially sign the COOKIE-ECHO. 613 */ 614 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL()); 615 616 /* 5.1 C) "A" shall then send the State Cookie received in the 617 * INIT ACK chunk in a COOKIE ECHO chunk, ... 618 */ 619 /* If there is any errors to report, send the ERROR chunk generated 620 * for unknown parameters as well. 621 */ 622 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO, 623 SCTP_CHUNK(err_chunk)); 624 625 return SCTP_DISPOSITION_CONSUME; 626 } 627 628 static bool sctp_auth_chunk_verify(struct net *net, struct sctp_chunk *chunk, 629 const struct sctp_association *asoc) 630 { 631 struct sctp_chunk auth; 632 633 if (!chunk->auth_chunk) 634 return true; 635 636 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo 637 * is supposed to be authenticated and we have to do delayed 638 * authentication. We've just recreated the association using 639 * the information in the cookie and now it's much easier to 640 * do the authentication. 641 */ 642 643 /* Make sure that we and the peer are AUTH capable */ 644 if (!net->sctp.auth_enable || !asoc->peer.auth_capable) 645 return false; 646 647 /* set-up our fake chunk so that we can process it */ 648 auth.skb = chunk->auth_chunk; 649 auth.asoc = chunk->asoc; 650 auth.sctp_hdr = chunk->sctp_hdr; 651 auth.chunk_hdr = (struct sctp_chunkhdr *) 652 skb_push(chunk->auth_chunk, 653 sizeof(struct sctp_chunkhdr)); 654 skb_pull(chunk->auth_chunk, sizeof(struct sctp_chunkhdr)); 655 auth.transport = chunk->transport; 656 657 return sctp_sf_authenticate(asoc, &auth) == SCTP_IERROR_NO_ERROR; 658 } 659 660 /* 661 * Respond to a normal COOKIE ECHO chunk. 662 * We are the side that is being asked for an association. 663 * 664 * Section: 5.1 Normal Establishment of an Association, D 665 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply 666 * with a COOKIE ACK chunk after building a TCB and moving to 667 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with 668 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK 669 * chunk MUST be the first chunk in the packet. 670 * 671 * IMPLEMENTATION NOTE: An implementation may choose to send the 672 * Communication Up notification to the SCTP user upon reception 673 * of a valid COOKIE ECHO chunk. 674 * 675 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 676 * D) Rules for packet carrying a COOKIE ECHO 677 * 678 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the 679 * Initial Tag received in the INIT ACK. 680 * 681 * - The receiver of a COOKIE ECHO follows the procedures in Section 5. 682 * 683 * Inputs 684 * (endpoint, asoc, chunk) 685 * 686 * Outputs 687 * (asoc, reply_msg, msg_up, timers, counters) 688 * 689 * The return value is the disposition of the chunk. 690 */ 691 enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net, 692 const struct sctp_endpoint *ep, 693 const struct sctp_association *asoc, 694 const union sctp_subtype type, 695 void *arg, 696 struct sctp_cmd_seq *commands) 697 { 698 struct sctp_ulpevent *ev, *ai_ev = NULL, *auth_ev = NULL; 699 struct sctp_association *new_asoc; 700 struct sctp_init_chunk *peer_init; 701 struct sctp_chunk *chunk = arg; 702 struct sctp_chunk *err_chk_p; 703 struct sctp_chunk *repl; 704 struct sock *sk; 705 int error = 0; 706 707 /* If the packet is an OOTB packet which is temporarily on the 708 * control endpoint, respond with an ABORT. 709 */ 710 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 711 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 712 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 713 } 714 715 /* Make sure that the COOKIE_ECHO chunk has a valid length. 716 * In this case, we check that we have enough for at least a 717 * chunk header. More detailed verification is done 718 * in sctp_unpack_cookie(). 719 */ 720 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 721 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 722 723 /* If the endpoint is not listening or if the number of associations 724 * on the TCP-style socket exceed the max backlog, respond with an 725 * ABORT. 726 */ 727 sk = ep->base.sk; 728 if (!sctp_sstate(sk, LISTENING) || 729 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk))) 730 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 731 732 /* "Decode" the chunk. We have no optional parameters so we 733 * are in good shape. 734 */ 735 chunk->subh.cookie_hdr = 736 (struct sctp_signed_cookie *)chunk->skb->data; 737 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 738 sizeof(struct sctp_chunkhdr))) 739 goto nomem; 740 741 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint 742 * "Z" will reply with a COOKIE ACK chunk after building a TCB 743 * and moving to the ESTABLISHED state. 744 */ 745 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 746 &err_chk_p); 747 748 /* FIXME: 749 * If the re-build failed, what is the proper error path 750 * from here? 751 * 752 * [We should abort the association. --piggy] 753 */ 754 if (!new_asoc) { 755 /* FIXME: Several errors are possible. A bad cookie should 756 * be silently discarded, but think about logging it too. 757 */ 758 switch (error) { 759 case -SCTP_IERROR_NOMEM: 760 goto nomem; 761 762 case -SCTP_IERROR_STALE_COOKIE: 763 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 764 err_chk_p); 765 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 766 767 case -SCTP_IERROR_BAD_SIG: 768 default: 769 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 770 } 771 } 772 773 774 /* Delay state machine commands until later. 775 * 776 * Re-build the bind address for the association is done in 777 * the sctp_unpack_cookie() already. 778 */ 779 /* This is a brand-new association, so these are not yet side 780 * effects--it is safe to run them here. 781 */ 782 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 783 784 if (!sctp_process_init(new_asoc, chunk, 785 &chunk->subh.cookie_hdr->c.peer_addr, 786 peer_init, GFP_ATOMIC)) 787 goto nomem_init; 788 789 /* SCTP-AUTH: Now that we've populate required fields in 790 * sctp_process_init, set up the association shared keys as 791 * necessary so that we can potentially authenticate the ACK 792 */ 793 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC); 794 if (error) 795 goto nomem_init; 796 797 if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) { 798 sctp_association_free(new_asoc); 799 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 800 } 801 802 repl = sctp_make_cookie_ack(new_asoc, chunk); 803 if (!repl) 804 goto nomem_init; 805 806 /* RFC 2960 5.1 Normal Establishment of an Association 807 * 808 * D) IMPLEMENTATION NOTE: An implementation may choose to 809 * send the Communication Up notification to the SCTP user 810 * upon reception of a valid COOKIE ECHO chunk. 811 */ 812 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0, 813 new_asoc->c.sinit_num_ostreams, 814 new_asoc->c.sinit_max_instreams, 815 NULL, GFP_ATOMIC); 816 if (!ev) 817 goto nomem_ev; 818 819 /* Sockets API Draft Section 5.3.1.6 820 * When a peer sends a Adaptation Layer Indication parameter , SCTP 821 * delivers this notification to inform the application that of the 822 * peers requested adaptation layer. 823 */ 824 if (new_asoc->peer.adaptation_ind) { 825 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc, 826 GFP_ATOMIC); 827 if (!ai_ev) 828 goto nomem_aiev; 829 } 830 831 if (!new_asoc->peer.auth_capable) { 832 auth_ev = sctp_ulpevent_make_authkey(new_asoc, 0, 833 SCTP_AUTH_NO_AUTH, 834 GFP_ATOMIC); 835 if (!auth_ev) 836 goto nomem_authev; 837 } 838 839 /* Add all the state machine commands now since we've created 840 * everything. This way we don't introduce memory corruptions 841 * during side-effect processing and correctly count established 842 * associations. 843 */ 844 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 845 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 846 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 847 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 848 SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS); 849 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 850 851 if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 852 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 853 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 854 855 /* This will send the COOKIE ACK */ 856 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 857 858 /* Queue the ASSOC_CHANGE event */ 859 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 860 861 /* Send up the Adaptation Layer Indication event */ 862 if (ai_ev) 863 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 864 SCTP_ULPEVENT(ai_ev)); 865 866 if (auth_ev) 867 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 868 SCTP_ULPEVENT(auth_ev)); 869 870 return SCTP_DISPOSITION_CONSUME; 871 872 nomem_authev: 873 sctp_ulpevent_free(ai_ev); 874 nomem_aiev: 875 sctp_ulpevent_free(ev); 876 nomem_ev: 877 sctp_chunk_free(repl); 878 nomem_init: 879 sctp_association_free(new_asoc); 880 nomem: 881 return SCTP_DISPOSITION_NOMEM; 882 } 883 884 /* 885 * Respond to a normal COOKIE ACK chunk. 886 * We are the side that is asking for an association. 887 * 888 * RFC 2960 5.1 Normal Establishment of an Association 889 * 890 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the 891 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie 892 * timer. It may also notify its ULP about the successful 893 * establishment of the association with a Communication Up 894 * notification (see Section 10). 895 * 896 * Verification Tag: 897 * Inputs 898 * (endpoint, asoc, chunk) 899 * 900 * Outputs 901 * (asoc, reply_msg, msg_up, timers, counters) 902 * 903 * The return value is the disposition of the chunk. 904 */ 905 enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net, 906 const struct sctp_endpoint *ep, 907 const struct sctp_association *asoc, 908 const union sctp_subtype type, 909 void *arg, 910 struct sctp_cmd_seq *commands) 911 { 912 struct sctp_chunk *chunk = arg; 913 struct sctp_ulpevent *ev; 914 915 if (!sctp_vtag_verify(chunk, asoc)) 916 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 917 918 /* Verify that the chunk length for the COOKIE-ACK is OK. 919 * If we don't do this, any bundled chunks may be junked. 920 */ 921 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 922 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 923 commands); 924 925 /* Reset init error count upon receipt of COOKIE-ACK, 926 * to avoid problems with the management of this 927 * counter in stale cookie situations when a transition back 928 * from the COOKIE-ECHOED state to the COOKIE-WAIT 929 * state is performed. 930 */ 931 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 932 933 /* Set peer label for connection. */ 934 security_inet_conn_established(ep->base.sk, chunk->skb); 935 936 /* RFC 2960 5.1 Normal Establishment of an Association 937 * 938 * E) Upon reception of the COOKIE ACK, endpoint "A" will move 939 * from the COOKIE-ECHOED state to the ESTABLISHED state, 940 * stopping the T1-cookie timer. 941 */ 942 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 943 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 944 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 945 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 946 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 947 SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS); 948 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 949 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 950 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 951 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 952 953 /* It may also notify its ULP about the successful 954 * establishment of the association with a Communication Up 955 * notification (see Section 10). 956 */ 957 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 958 0, asoc->c.sinit_num_ostreams, 959 asoc->c.sinit_max_instreams, 960 NULL, GFP_ATOMIC); 961 962 if (!ev) 963 goto nomem; 964 965 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 966 967 /* Sockets API Draft Section 5.3.1.6 968 * When a peer sends a Adaptation Layer Indication parameter , SCTP 969 * delivers this notification to inform the application that of the 970 * peers requested adaptation layer. 971 */ 972 if (asoc->peer.adaptation_ind) { 973 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC); 974 if (!ev) 975 goto nomem; 976 977 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 978 SCTP_ULPEVENT(ev)); 979 } 980 981 if (!asoc->peer.auth_capable) { 982 ev = sctp_ulpevent_make_authkey(asoc, 0, SCTP_AUTH_NO_AUTH, 983 GFP_ATOMIC); 984 if (!ev) 985 goto nomem; 986 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 987 SCTP_ULPEVENT(ev)); 988 } 989 990 return SCTP_DISPOSITION_CONSUME; 991 nomem: 992 return SCTP_DISPOSITION_NOMEM; 993 } 994 995 /* Generate and sendout a heartbeat packet. */ 996 static enum sctp_disposition sctp_sf_heartbeat( 997 const struct sctp_endpoint *ep, 998 const struct sctp_association *asoc, 999 const union sctp_subtype type, 1000 void *arg, 1001 struct sctp_cmd_seq *commands) 1002 { 1003 struct sctp_transport *transport = (struct sctp_transport *) arg; 1004 struct sctp_chunk *reply; 1005 1006 /* Send a heartbeat to our peer. */ 1007 reply = sctp_make_heartbeat(asoc, transport, 0); 1008 if (!reply) 1009 return SCTP_DISPOSITION_NOMEM; 1010 1011 /* Set rto_pending indicating that an RTT measurement 1012 * is started with this heartbeat chunk. 1013 */ 1014 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING, 1015 SCTP_TRANSPORT(transport)); 1016 1017 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1018 return SCTP_DISPOSITION_CONSUME; 1019 } 1020 1021 /* Generate a HEARTBEAT packet on the given transport. */ 1022 enum sctp_disposition sctp_sf_sendbeat_8_3(struct net *net, 1023 const struct sctp_endpoint *ep, 1024 const struct sctp_association *asoc, 1025 const union sctp_subtype type, 1026 void *arg, 1027 struct sctp_cmd_seq *commands) 1028 { 1029 struct sctp_transport *transport = (struct sctp_transport *) arg; 1030 1031 if (asoc->overall_error_count >= asoc->max_retrans) { 1032 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 1033 SCTP_ERROR(ETIMEDOUT)); 1034 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 1035 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 1036 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 1037 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 1038 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 1039 return SCTP_DISPOSITION_DELETE_TCB; 1040 } 1041 1042 /* Section 3.3.5. 1043 * The Sender-specific Heartbeat Info field should normally include 1044 * information about the sender's current time when this HEARTBEAT 1045 * chunk is sent and the destination transport address to which this 1046 * HEARTBEAT is sent (see Section 8.3). 1047 */ 1048 1049 if (transport->param_flags & SPP_HB_ENABLE) { 1050 if (SCTP_DISPOSITION_NOMEM == 1051 sctp_sf_heartbeat(ep, asoc, type, arg, 1052 commands)) 1053 return SCTP_DISPOSITION_NOMEM; 1054 1055 /* Set transport error counter and association error counter 1056 * when sending heartbeat. 1057 */ 1058 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 1059 SCTP_TRANSPORT(transport)); 1060 } 1061 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE, 1062 SCTP_TRANSPORT(transport)); 1063 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE, 1064 SCTP_TRANSPORT(transport)); 1065 1066 return SCTP_DISPOSITION_CONSUME; 1067 } 1068 1069 /* resend asoc strreset_chunk. */ 1070 enum sctp_disposition sctp_sf_send_reconf(struct net *net, 1071 const struct sctp_endpoint *ep, 1072 const struct sctp_association *asoc, 1073 const union sctp_subtype type, 1074 void *arg, 1075 struct sctp_cmd_seq *commands) 1076 { 1077 struct sctp_transport *transport = arg; 1078 1079 if (asoc->overall_error_count >= asoc->max_retrans) { 1080 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 1081 SCTP_ERROR(ETIMEDOUT)); 1082 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 1083 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 1084 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 1085 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 1086 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 1087 return SCTP_DISPOSITION_DELETE_TCB; 1088 } 1089 1090 sctp_chunk_hold(asoc->strreset_chunk); 1091 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1092 SCTP_CHUNK(asoc->strreset_chunk)); 1093 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 1094 1095 return SCTP_DISPOSITION_CONSUME; 1096 } 1097 1098 /* send hb chunk with padding for PLPMUTD. */ 1099 enum sctp_disposition sctp_sf_send_probe(struct net *net, 1100 const struct sctp_endpoint *ep, 1101 const struct sctp_association *asoc, 1102 const union sctp_subtype type, 1103 void *arg, 1104 struct sctp_cmd_seq *commands) 1105 { 1106 struct sctp_transport *transport = (struct sctp_transport *)arg; 1107 struct sctp_chunk *reply; 1108 1109 if (!sctp_transport_pl_enabled(transport)) 1110 return SCTP_DISPOSITION_CONSUME; 1111 1112 sctp_transport_pl_send(transport); 1113 1114 reply = sctp_make_heartbeat(asoc, transport, transport->pl.probe_size); 1115 if (!reply) 1116 return SCTP_DISPOSITION_NOMEM; 1117 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1118 sctp_add_cmd_sf(commands, SCTP_CMD_PROBE_TIMER_UPDATE, 1119 SCTP_TRANSPORT(transport)); 1120 1121 return SCTP_DISPOSITION_CONSUME; 1122 } 1123 1124 /* 1125 * Process an heartbeat request. 1126 * 1127 * Section: 8.3 Path Heartbeat 1128 * The receiver of the HEARTBEAT should immediately respond with a 1129 * HEARTBEAT ACK that contains the Heartbeat Information field copied 1130 * from the received HEARTBEAT chunk. 1131 * 1132 * Verification Tag: 8.5 Verification Tag [Normal verification] 1133 * When receiving an SCTP packet, the endpoint MUST ensure that the 1134 * value in the Verification Tag field of the received SCTP packet 1135 * matches its own Tag. If the received Verification Tag value does not 1136 * match the receiver's own tag value, the receiver shall silently 1137 * discard the packet and shall not process it any further except for 1138 * those cases listed in Section 8.5.1 below. 1139 * 1140 * Inputs 1141 * (endpoint, asoc, chunk) 1142 * 1143 * Outputs 1144 * (asoc, reply_msg, msg_up, timers, counters) 1145 * 1146 * The return value is the disposition of the chunk. 1147 */ 1148 enum sctp_disposition sctp_sf_beat_8_3(struct net *net, 1149 const struct sctp_endpoint *ep, 1150 const struct sctp_association *asoc, 1151 const union sctp_subtype type, 1152 void *arg, struct sctp_cmd_seq *commands) 1153 { 1154 struct sctp_paramhdr *param_hdr; 1155 struct sctp_chunk *chunk = arg; 1156 struct sctp_chunk *reply; 1157 size_t paylen = 0; 1158 1159 if (!sctp_vtag_verify(chunk, asoc)) 1160 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1161 1162 /* Make sure that the HEARTBEAT chunk has a valid length. */ 1163 if (!sctp_chunk_length_valid(chunk, 1164 sizeof(struct sctp_heartbeat_chunk))) 1165 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1166 commands); 1167 1168 /* 8.3 The receiver of the HEARTBEAT should immediately 1169 * respond with a HEARTBEAT ACK that contains the Heartbeat 1170 * Information field copied from the received HEARTBEAT chunk. 1171 */ 1172 chunk->subh.hb_hdr = (struct sctp_heartbeathdr *)chunk->skb->data; 1173 param_hdr = (struct sctp_paramhdr *)chunk->subh.hb_hdr; 1174 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(struct sctp_chunkhdr); 1175 1176 if (ntohs(param_hdr->length) > paylen) 1177 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 1178 param_hdr, commands); 1179 1180 if (!pskb_pull(chunk->skb, paylen)) 1181 goto nomem; 1182 1183 reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen); 1184 if (!reply) 1185 goto nomem; 1186 1187 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1188 return SCTP_DISPOSITION_CONSUME; 1189 1190 nomem: 1191 return SCTP_DISPOSITION_NOMEM; 1192 } 1193 1194 /* 1195 * Process the returning HEARTBEAT ACK. 1196 * 1197 * Section: 8.3 Path Heartbeat 1198 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT 1199 * should clear the error counter of the destination transport 1200 * address to which the HEARTBEAT was sent, and mark the destination 1201 * transport address as active if it is not so marked. The endpoint may 1202 * optionally report to the upper layer when an inactive destination 1203 * address is marked as active due to the reception of the latest 1204 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also 1205 * clear the association overall error count as well (as defined 1206 * in section 8.1). 1207 * 1208 * The receiver of the HEARTBEAT ACK should also perform an RTT 1209 * measurement for that destination transport address using the time 1210 * value carried in the HEARTBEAT ACK chunk. 1211 * 1212 * Verification Tag: 8.5 Verification Tag [Normal verification] 1213 * 1214 * Inputs 1215 * (endpoint, asoc, chunk) 1216 * 1217 * Outputs 1218 * (asoc, reply_msg, msg_up, timers, counters) 1219 * 1220 * The return value is the disposition of the chunk. 1221 */ 1222 enum sctp_disposition sctp_sf_backbeat_8_3(struct net *net, 1223 const struct sctp_endpoint *ep, 1224 const struct sctp_association *asoc, 1225 const union sctp_subtype type, 1226 void *arg, 1227 struct sctp_cmd_seq *commands) 1228 { 1229 struct sctp_sender_hb_info *hbinfo; 1230 struct sctp_chunk *chunk = arg; 1231 struct sctp_transport *link; 1232 unsigned long max_interval; 1233 union sctp_addr from_addr; 1234 1235 if (!sctp_vtag_verify(chunk, asoc)) 1236 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1237 1238 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */ 1239 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr) + 1240 sizeof(*hbinfo))) 1241 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1242 commands); 1243 1244 hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data; 1245 /* Make sure that the length of the parameter is what we expect */ 1246 if (ntohs(hbinfo->param_hdr.length) != sizeof(*hbinfo)) 1247 return SCTP_DISPOSITION_DISCARD; 1248 1249 from_addr = hbinfo->daddr; 1250 link = sctp_assoc_lookup_paddr(asoc, &from_addr); 1251 1252 /* This should never happen, but lets log it if so. */ 1253 if (unlikely(!link)) { 1254 if (from_addr.sa.sa_family == AF_INET6) { 1255 net_warn_ratelimited("%s association %p could not find address %pI6\n", 1256 __func__, 1257 asoc, 1258 &from_addr.v6.sin6_addr); 1259 } else { 1260 net_warn_ratelimited("%s association %p could not find address %pI4\n", 1261 __func__, 1262 asoc, 1263 &from_addr.v4.sin_addr.s_addr); 1264 } 1265 return SCTP_DISPOSITION_DISCARD; 1266 } 1267 1268 /* Validate the 64-bit random nonce. */ 1269 if (hbinfo->hb_nonce != link->hb_nonce) 1270 return SCTP_DISPOSITION_DISCARD; 1271 1272 if (hbinfo->probe_size) { 1273 if (hbinfo->probe_size != link->pl.probe_size || 1274 !sctp_transport_pl_enabled(link)) 1275 return SCTP_DISPOSITION_DISCARD; 1276 1277 sctp_transport_pl_recv(link); 1278 if (link->pl.state == SCTP_PL_COMPLETE) 1279 return SCTP_DISPOSITION_CONSUME; 1280 1281 return sctp_sf_send_probe(net, ep, asoc, type, link, commands); 1282 } 1283 1284 max_interval = link->hbinterval + link->rto; 1285 1286 /* Check if the timestamp looks valid. */ 1287 if (time_after(hbinfo->sent_at, jiffies) || 1288 time_after(jiffies, hbinfo->sent_at + max_interval)) { 1289 pr_debug("%s: HEARTBEAT ACK with invalid timestamp received " 1290 "for transport:%p\n", __func__, link); 1291 1292 return SCTP_DISPOSITION_DISCARD; 1293 } 1294 1295 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of 1296 * the HEARTBEAT should clear the error counter of the 1297 * destination transport address to which the HEARTBEAT was 1298 * sent and mark the destination transport address as active if 1299 * it is not so marked. 1300 */ 1301 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); 1302 1303 return SCTP_DISPOSITION_CONSUME; 1304 } 1305 1306 /* Helper function to send out an abort for the restart 1307 * condition. 1308 */ 1309 static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa, 1310 struct sctp_chunk *init, 1311 struct sctp_cmd_seq *commands) 1312 { 1313 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); 1314 union sctp_addr_param *addrparm; 1315 struct sctp_errhdr *errhdr; 1316 char buffer[sizeof(*errhdr) + sizeof(*addrparm)]; 1317 struct sctp_endpoint *ep; 1318 struct sctp_packet *pkt; 1319 int len; 1320 1321 /* Build the error on the stack. We are way to malloc crazy 1322 * throughout the code today. 1323 */ 1324 errhdr = (struct sctp_errhdr *)buffer; 1325 addrparm = (union sctp_addr_param *)errhdr->variable; 1326 1327 /* Copy into a parm format. */ 1328 len = af->to_addr_param(ssa, addrparm); 1329 len += sizeof(*errhdr); 1330 1331 errhdr->cause = SCTP_ERROR_RESTART; 1332 errhdr->length = htons(len); 1333 1334 /* Assign to the control socket. */ 1335 ep = sctp_sk(net->sctp.ctl_sock)->ep; 1336 1337 /* Association is NULL since this may be a restart attack and we 1338 * want to send back the attacker's vtag. 1339 */ 1340 pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len); 1341 1342 if (!pkt) 1343 goto out; 1344 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); 1345 1346 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1347 1348 /* Discard the rest of the inbound packet. */ 1349 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 1350 1351 out: 1352 /* Even if there is no memory, treat as a failure so 1353 * the packet will get dropped. 1354 */ 1355 return 0; 1356 } 1357 1358 static bool list_has_sctp_addr(const struct list_head *list, 1359 union sctp_addr *ipaddr) 1360 { 1361 struct sctp_transport *addr; 1362 1363 list_for_each_entry(addr, list, transports) { 1364 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr)) 1365 return true; 1366 } 1367 1368 return false; 1369 } 1370 /* A restart is occurring, check to make sure no new addresses 1371 * are being added as we may be under a takeover attack. 1372 */ 1373 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, 1374 const struct sctp_association *asoc, 1375 struct sctp_chunk *init, 1376 struct sctp_cmd_seq *commands) 1377 { 1378 struct net *net = new_asoc->base.net; 1379 struct sctp_transport *new_addr; 1380 int ret = 1; 1381 1382 /* Implementor's Guide - Section 5.2.2 1383 * ... 1384 * Before responding the endpoint MUST check to see if the 1385 * unexpected INIT adds new addresses to the association. If new 1386 * addresses are added to the association, the endpoint MUST respond 1387 * with an ABORT.. 1388 */ 1389 1390 /* Search through all current addresses and make sure 1391 * we aren't adding any new ones. 1392 */ 1393 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list, 1394 transports) { 1395 if (!list_has_sctp_addr(&asoc->peer.transport_addr_list, 1396 &new_addr->ipaddr)) { 1397 sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init, 1398 commands); 1399 ret = 0; 1400 break; 1401 } 1402 } 1403 1404 /* Return success if all addresses were found. */ 1405 return ret; 1406 } 1407 1408 /* Populate the verification/tie tags based on overlapping INIT 1409 * scenario. 1410 * 1411 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. 1412 */ 1413 static void sctp_tietags_populate(struct sctp_association *new_asoc, 1414 const struct sctp_association *asoc) 1415 { 1416 switch (asoc->state) { 1417 1418 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ 1419 1420 case SCTP_STATE_COOKIE_WAIT: 1421 new_asoc->c.my_vtag = asoc->c.my_vtag; 1422 new_asoc->c.my_ttag = asoc->c.my_vtag; 1423 new_asoc->c.peer_ttag = 0; 1424 break; 1425 1426 case SCTP_STATE_COOKIE_ECHOED: 1427 new_asoc->c.my_vtag = asoc->c.my_vtag; 1428 new_asoc->c.my_ttag = asoc->c.my_vtag; 1429 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1430 break; 1431 1432 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, 1433 * COOKIE-WAIT and SHUTDOWN-ACK-SENT 1434 */ 1435 default: 1436 new_asoc->c.my_ttag = asoc->c.my_vtag; 1437 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1438 break; 1439 } 1440 1441 /* Other parameters for the endpoint SHOULD be copied from the 1442 * existing parameters of the association (e.g. number of 1443 * outbound streams) into the INIT ACK and cookie. 1444 */ 1445 new_asoc->rwnd = asoc->rwnd; 1446 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; 1447 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; 1448 new_asoc->c.initial_tsn = asoc->c.initial_tsn; 1449 } 1450 1451 /* 1452 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO 1453 * handling action. 1454 * 1455 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. 1456 * 1457 * Returns value representing action to be taken. These action values 1458 * correspond to Action/Description values in RFC 2960, Table 2. 1459 */ 1460 static char sctp_tietags_compare(struct sctp_association *new_asoc, 1461 const struct sctp_association *asoc) 1462 { 1463 /* In this case, the peer may have restarted. */ 1464 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1465 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && 1466 (asoc->c.my_vtag == new_asoc->c.my_ttag) && 1467 (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) 1468 return 'A'; 1469 1470 /* Collision case B. */ 1471 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1472 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || 1473 (0 == asoc->c.peer_vtag))) { 1474 return 'B'; 1475 } 1476 1477 /* Collision case D. */ 1478 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1479 (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) 1480 return 'D'; 1481 1482 /* Collision case C. */ 1483 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1484 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && 1485 (0 == new_asoc->c.my_ttag) && 1486 (0 == new_asoc->c.peer_ttag)) 1487 return 'C'; 1488 1489 /* No match to any of the special cases; discard this packet. */ 1490 return 'E'; 1491 } 1492 1493 /* Common helper routine for both duplicate and simultaneous INIT 1494 * chunk handling. 1495 */ 1496 static enum sctp_disposition sctp_sf_do_unexpected_init( 1497 struct net *net, 1498 const struct sctp_endpoint *ep, 1499 const struct sctp_association *asoc, 1500 const union sctp_subtype type, 1501 void *arg, 1502 struct sctp_cmd_seq *commands) 1503 { 1504 struct sctp_chunk *chunk = arg, *repl, *err_chunk; 1505 struct sctp_unrecognized_param *unk_param; 1506 struct sctp_association *new_asoc; 1507 enum sctp_disposition retval; 1508 struct sctp_packet *packet; 1509 int len; 1510 1511 /* Update socket peer label if first association. */ 1512 if (security_sctp_assoc_request((struct sctp_endpoint *)ep, 1513 chunk->skb)) 1514 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1515 1516 /* 6.10 Bundling 1517 * An endpoint MUST NOT bundle INIT, INIT ACK or 1518 * SHUTDOWN COMPLETE with any other chunks. 1519 * 1520 * IG Section 2.11.2 1521 * Furthermore, we require that the receiver of an INIT chunk MUST 1522 * enforce these rules by silently discarding an arriving packet 1523 * with an INIT chunk that is bundled with other chunks. 1524 */ 1525 if (!chunk->singleton) 1526 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1527 1528 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 1529 * Tag. 1530 */ 1531 if (chunk->sctp_hdr->vtag != 0) 1532 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 1533 1534 /* Make sure that the INIT chunk has a valid length. 1535 * In this case, we generate a protocol violation since we have 1536 * an association established. 1537 */ 1538 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk))) 1539 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1540 commands); 1541 1542 if (SCTP_INPUT_CB(chunk->skb)->encap_port != chunk->transport->encap_port) 1543 return sctp_sf_new_encap_port(net, ep, asoc, type, arg, commands); 1544 1545 /* Grab the INIT header. */ 1546 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 1547 1548 /* Tag the variable length parameters. */ 1549 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 1550 1551 /* Verify the INIT chunk before processing it. */ 1552 err_chunk = NULL; 1553 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 1554 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 1555 &err_chunk)) { 1556 /* This chunk contains fatal error. It is to be discarded. 1557 * Send an ABORT, with causes if there is any. 1558 */ 1559 if (err_chunk) { 1560 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 1561 (__u8 *)(err_chunk->chunk_hdr) + 1562 sizeof(struct sctp_chunkhdr), 1563 ntohs(err_chunk->chunk_hdr->length) - 1564 sizeof(struct sctp_chunkhdr)); 1565 1566 if (packet) { 1567 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 1568 SCTP_PACKET(packet)); 1569 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1570 retval = SCTP_DISPOSITION_CONSUME; 1571 } else { 1572 retval = SCTP_DISPOSITION_NOMEM; 1573 } 1574 goto cleanup; 1575 } else { 1576 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 1577 commands); 1578 } 1579 } 1580 1581 /* 1582 * Other parameters for the endpoint SHOULD be copied from the 1583 * existing parameters of the association (e.g. number of 1584 * outbound streams) into the INIT ACK and cookie. 1585 * FIXME: We are copying parameters from the endpoint not the 1586 * association. 1587 */ 1588 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 1589 if (!new_asoc) 1590 goto nomem; 1591 1592 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 1593 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0) 1594 goto nomem; 1595 1596 /* In the outbound INIT ACK the endpoint MUST copy its current 1597 * Verification Tag and Peers Verification tag into a reserved 1598 * place (local tie-tag and per tie-tag) within the state cookie. 1599 */ 1600 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 1601 (struct sctp_init_chunk *)chunk->chunk_hdr, 1602 GFP_ATOMIC)) 1603 goto nomem; 1604 1605 /* Make sure no new addresses are being added during the 1606 * restart. Do not do this check for COOKIE-WAIT state, 1607 * since there are no peer addresses to check against. 1608 * Upon return an ABORT will have been sent if needed. 1609 */ 1610 if (!sctp_state(asoc, COOKIE_WAIT)) { 1611 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, 1612 commands)) { 1613 retval = SCTP_DISPOSITION_CONSUME; 1614 goto nomem_retval; 1615 } 1616 } 1617 1618 sctp_tietags_populate(new_asoc, asoc); 1619 1620 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 1621 1622 /* If there are errors need to be reported for unknown parameters, 1623 * make sure to reserve enough room in the INIT ACK for them. 1624 */ 1625 len = 0; 1626 if (err_chunk) { 1627 len = ntohs(err_chunk->chunk_hdr->length) - 1628 sizeof(struct sctp_chunkhdr); 1629 } 1630 1631 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 1632 if (!repl) 1633 goto nomem; 1634 1635 /* If there are errors need to be reported for unknown parameters, 1636 * include them in the outgoing INIT ACK as "Unrecognized parameter" 1637 * parameter. 1638 */ 1639 if (err_chunk) { 1640 /* Get the "Unrecognized parameter" parameter(s) out of the 1641 * ERROR chunk generated by sctp_verify_init(). Since the 1642 * error cause code for "unknown parameter" and the 1643 * "Unrecognized parameter" type is the same, we can 1644 * construct the parameters in INIT ACK by copying the 1645 * ERROR causes over. 1646 */ 1647 unk_param = (struct sctp_unrecognized_param *) 1648 ((__u8 *)(err_chunk->chunk_hdr) + 1649 sizeof(struct sctp_chunkhdr)); 1650 /* Replace the cause code with the "Unrecognized parameter" 1651 * parameter type. 1652 */ 1653 sctp_addto_chunk(repl, len, unk_param); 1654 } 1655 1656 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1657 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1658 1659 /* 1660 * Note: After sending out INIT ACK with the State Cookie parameter, 1661 * "Z" MUST NOT allocate any resources for this new association. 1662 * Otherwise, "Z" will be vulnerable to resource attacks. 1663 */ 1664 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1665 retval = SCTP_DISPOSITION_CONSUME; 1666 1667 return retval; 1668 1669 nomem: 1670 retval = SCTP_DISPOSITION_NOMEM; 1671 nomem_retval: 1672 if (new_asoc) 1673 sctp_association_free(new_asoc); 1674 cleanup: 1675 if (err_chunk) 1676 sctp_chunk_free(err_chunk); 1677 return retval; 1678 } 1679 1680 /* 1681 * Handle simultaneous INIT. 1682 * This means we started an INIT and then we got an INIT request from 1683 * our peer. 1684 * 1685 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) 1686 * This usually indicates an initialization collision, i.e., each 1687 * endpoint is attempting, at about the same time, to establish an 1688 * association with the other endpoint. 1689 * 1690 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an 1691 * endpoint MUST respond with an INIT ACK using the same parameters it 1692 * sent in its original INIT chunk (including its Verification Tag, 1693 * unchanged). These original parameters are combined with those from the 1694 * newly received INIT chunk. The endpoint shall also generate a State 1695 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its 1696 * INIT to calculate the State Cookie. 1697 * 1698 * After that, the endpoint MUST NOT change its state, the T1-init 1699 * timer shall be left running and the corresponding TCB MUST NOT be 1700 * destroyed. The normal procedures for handling State Cookies when 1701 * a TCB exists will resolve the duplicate INITs to a single association. 1702 * 1703 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate 1704 * its Tie-Tags with the Tag information of itself and its peer (see 1705 * section 5.2.2 for a description of the Tie-Tags). 1706 * 1707 * Verification Tag: Not explicit, but an INIT can not have a valid 1708 * verification tag, so we skip the check. 1709 * 1710 * Inputs 1711 * (endpoint, asoc, chunk) 1712 * 1713 * Outputs 1714 * (asoc, reply_msg, msg_up, timers, counters) 1715 * 1716 * The return value is the disposition of the chunk. 1717 */ 1718 enum sctp_disposition sctp_sf_do_5_2_1_siminit( 1719 struct net *net, 1720 const struct sctp_endpoint *ep, 1721 const struct sctp_association *asoc, 1722 const union sctp_subtype type, 1723 void *arg, 1724 struct sctp_cmd_seq *commands) 1725 { 1726 /* Call helper to do the real work for both simultaneous and 1727 * duplicate INIT chunk handling. 1728 */ 1729 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1730 } 1731 1732 /* 1733 * Handle duplicated INIT messages. These are usually delayed 1734 * restransmissions. 1735 * 1736 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, 1737 * COOKIE-ECHOED and COOKIE-WAIT 1738 * 1739 * Unless otherwise stated, upon reception of an unexpected INIT for 1740 * this association, the endpoint shall generate an INIT ACK with a 1741 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its 1742 * current Verification Tag and peer's Verification Tag into a reserved 1743 * place within the state cookie. We shall refer to these locations as 1744 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet 1745 * containing this INIT ACK MUST carry a Verification Tag value equal to 1746 * the Initiation Tag found in the unexpected INIT. And the INIT ACK 1747 * MUST contain a new Initiation Tag (randomly generated see Section 1748 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the 1749 * existing parameters of the association (e.g. number of outbound 1750 * streams) into the INIT ACK and cookie. 1751 * 1752 * After sending out the INIT ACK, the endpoint shall take no further 1753 * actions, i.e., the existing association, including its current state, 1754 * and the corresponding TCB MUST NOT be changed. 1755 * 1756 * Note: Only when a TCB exists and the association is not in a COOKIE- 1757 * WAIT state are the Tie-Tags populated. For a normal association INIT 1758 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be 1759 * set to 0 (indicating that no previous TCB existed). The INIT ACK and 1760 * State Cookie are populated as specified in section 5.2.1. 1761 * 1762 * Verification Tag: Not specified, but an INIT has no way of knowing 1763 * what the verification tag could be, so we ignore it. 1764 * 1765 * Inputs 1766 * (endpoint, asoc, chunk) 1767 * 1768 * Outputs 1769 * (asoc, reply_msg, msg_up, timers, counters) 1770 * 1771 * The return value is the disposition of the chunk. 1772 */ 1773 enum sctp_disposition sctp_sf_do_5_2_2_dupinit( 1774 struct net *net, 1775 const struct sctp_endpoint *ep, 1776 const struct sctp_association *asoc, 1777 const union sctp_subtype type, 1778 void *arg, 1779 struct sctp_cmd_seq *commands) 1780 { 1781 /* Call helper to do the real work for both simultaneous and 1782 * duplicate INIT chunk handling. 1783 */ 1784 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1785 } 1786 1787 1788 /* 1789 * Unexpected INIT-ACK handler. 1790 * 1791 * Section 5.2.3 1792 * If an INIT ACK received by an endpoint in any state other than the 1793 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk. 1794 * An unexpected INIT ACK usually indicates the processing of an old or 1795 * duplicated INIT chunk. 1796 */ 1797 enum sctp_disposition sctp_sf_do_5_2_3_initack( 1798 struct net *net, 1799 const struct sctp_endpoint *ep, 1800 const struct sctp_association *asoc, 1801 const union sctp_subtype type, 1802 void *arg, 1803 struct sctp_cmd_seq *commands) 1804 { 1805 /* Per the above section, we'll discard the chunk if we have an 1806 * endpoint. If this is an OOTB INIT-ACK, treat it as such. 1807 */ 1808 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) 1809 return sctp_sf_ootb(net, ep, asoc, type, arg, commands); 1810 else 1811 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 1812 } 1813 1814 static int sctp_sf_do_assoc_update(struct sctp_association *asoc, 1815 struct sctp_association *new, 1816 struct sctp_cmd_seq *cmds) 1817 { 1818 struct net *net = asoc->base.net; 1819 struct sctp_chunk *abort; 1820 1821 if (!sctp_assoc_update(asoc, new)) 1822 return 0; 1823 1824 abort = sctp_make_abort(asoc, NULL, sizeof(struct sctp_errhdr)); 1825 if (abort) { 1826 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 1827 sctp_add_cmd_sf(cmds, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 1828 } 1829 sctp_add_cmd_sf(cmds, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNABORTED)); 1830 sctp_add_cmd_sf(cmds, SCTP_CMD_ASSOC_FAILED, 1831 SCTP_PERR(SCTP_ERROR_RSRC_LOW)); 1832 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 1833 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 1834 1835 return -ENOMEM; 1836 } 1837 1838 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') 1839 * 1840 * Section 5.2.4 1841 * A) In this case, the peer may have restarted. 1842 */ 1843 static enum sctp_disposition sctp_sf_do_dupcook_a( 1844 struct net *net, 1845 const struct sctp_endpoint *ep, 1846 const struct sctp_association *asoc, 1847 struct sctp_chunk *chunk, 1848 struct sctp_cmd_seq *commands, 1849 struct sctp_association *new_asoc) 1850 { 1851 struct sctp_init_chunk *peer_init; 1852 enum sctp_disposition disposition; 1853 struct sctp_ulpevent *ev; 1854 struct sctp_chunk *repl; 1855 struct sctp_chunk *err; 1856 1857 /* new_asoc is a brand-new association, so these are not yet 1858 * side effects--it is safe to run them here. 1859 */ 1860 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1861 1862 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1863 GFP_ATOMIC)) 1864 goto nomem; 1865 1866 if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC)) 1867 goto nomem; 1868 1869 if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) 1870 return SCTP_DISPOSITION_DISCARD; 1871 1872 /* Make sure no new addresses are being added during the 1873 * restart. Though this is a pretty complicated attack 1874 * since you'd have to get inside the cookie. 1875 */ 1876 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) 1877 return SCTP_DISPOSITION_CONSUME; 1878 1879 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes 1880 * the peer has restarted (Action A), it MUST NOT setup a new 1881 * association but instead resend the SHUTDOWN ACK and send an ERROR 1882 * chunk with a "Cookie Received while Shutting Down" error cause to 1883 * its peer. 1884 */ 1885 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { 1886 disposition = sctp_sf_do_9_2_reshutack(net, ep, asoc, 1887 SCTP_ST_CHUNK(chunk->chunk_hdr->type), 1888 chunk, commands); 1889 if (SCTP_DISPOSITION_NOMEM == disposition) 1890 goto nomem; 1891 1892 err = sctp_make_op_error(asoc, chunk, 1893 SCTP_ERROR_COOKIE_IN_SHUTDOWN, 1894 NULL, 0, 0); 1895 if (err) 1896 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1897 SCTP_CHUNK(err)); 1898 1899 return SCTP_DISPOSITION_CONSUME; 1900 } 1901 1902 /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked 1903 * data. Consider the optional choice of resending of this data. 1904 */ 1905 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 1906 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1907 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); 1908 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 1909 1910 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue 1911 * and ASCONF-ACK cache. 1912 */ 1913 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1914 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 1915 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL()); 1916 1917 /* Update the content of current association. */ 1918 if (sctp_sf_do_assoc_update((struct sctp_association *)asoc, new_asoc, commands)) 1919 goto nomem; 1920 1921 repl = sctp_make_cookie_ack(asoc, chunk); 1922 if (!repl) 1923 goto nomem; 1924 1925 /* Report association restart to upper layer. */ 1926 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, 1927 asoc->c.sinit_num_ostreams, 1928 asoc->c.sinit_max_instreams, 1929 NULL, GFP_ATOMIC); 1930 if (!ev) 1931 goto nomem_ev; 1932 1933 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1934 if ((sctp_state(asoc, SHUTDOWN_PENDING) || 1935 sctp_state(asoc, SHUTDOWN_SENT)) && 1936 (sctp_sstate(asoc->base.sk, CLOSING) || 1937 sock_flag(asoc->base.sk, SOCK_DEAD))) { 1938 /* If the socket has been closed by user, don't 1939 * transition to ESTABLISHED. Instead trigger SHUTDOWN 1940 * bundled with COOKIE_ACK. 1941 */ 1942 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1943 return sctp_sf_do_9_2_start_shutdown(net, ep, asoc, 1944 SCTP_ST_CHUNK(0), repl, 1945 commands); 1946 } else { 1947 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1948 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1949 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1950 } 1951 return SCTP_DISPOSITION_CONSUME; 1952 1953 nomem_ev: 1954 sctp_chunk_free(repl); 1955 nomem: 1956 return SCTP_DISPOSITION_NOMEM; 1957 } 1958 1959 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') 1960 * 1961 * Section 5.2.4 1962 * B) In this case, both sides may be attempting to start an association 1963 * at about the same time but the peer endpoint started its INIT 1964 * after responding to the local endpoint's INIT 1965 */ 1966 /* This case represents an initialization collision. */ 1967 static enum sctp_disposition sctp_sf_do_dupcook_b( 1968 struct net *net, 1969 const struct sctp_endpoint *ep, 1970 const struct sctp_association *asoc, 1971 struct sctp_chunk *chunk, 1972 struct sctp_cmd_seq *commands, 1973 struct sctp_association *new_asoc) 1974 { 1975 struct sctp_init_chunk *peer_init; 1976 struct sctp_chunk *repl; 1977 1978 /* new_asoc is a brand-new association, so these are not yet 1979 * side effects--it is safe to run them here. 1980 */ 1981 peer_init = &chunk->subh.cookie_hdr->c.peer_init[0]; 1982 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1983 GFP_ATOMIC)) 1984 goto nomem; 1985 1986 if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC)) 1987 goto nomem; 1988 1989 if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) 1990 return SCTP_DISPOSITION_DISCARD; 1991 1992 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1993 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1994 if (asoc->state < SCTP_STATE_ESTABLISHED) 1995 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 1996 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 1997 1998 /* Update the content of current association. */ 1999 if (sctp_sf_do_assoc_update((struct sctp_association *)asoc, new_asoc, commands)) 2000 goto nomem; 2001 2002 repl = sctp_make_cookie_ack(asoc, chunk); 2003 if (!repl) 2004 goto nomem; 2005 2006 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 2007 2008 /* RFC 2960 5.1 Normal Establishment of an Association 2009 * 2010 * D) IMPLEMENTATION NOTE: An implementation may choose to 2011 * send the Communication Up notification to the SCTP user 2012 * upon reception of a valid COOKIE ECHO chunk. 2013 * 2014 * Sadly, this needs to be implemented as a side-effect, because 2015 * we are not guaranteed to have set the association id of the real 2016 * association and so these notifications need to be delayed until 2017 * the association id is allocated. 2018 */ 2019 2020 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP)); 2021 2022 /* Sockets API Draft Section 5.3.1.6 2023 * When a peer sends a Adaptation Layer Indication parameter , SCTP 2024 * delivers this notification to inform the application that of the 2025 * peers requested adaptation layer. 2026 * 2027 * This also needs to be done as a side effect for the same reason as 2028 * above. 2029 */ 2030 if (asoc->peer.adaptation_ind) 2031 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL()); 2032 2033 if (!asoc->peer.auth_capable) 2034 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_NO_AUTH, SCTP_NULL()); 2035 2036 return SCTP_DISPOSITION_CONSUME; 2037 2038 nomem: 2039 return SCTP_DISPOSITION_NOMEM; 2040 } 2041 2042 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') 2043 * 2044 * Section 5.2.4 2045 * C) In this case, the local endpoint's cookie has arrived late. 2046 * Before it arrived, the local endpoint sent an INIT and received an 2047 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag 2048 * but a new tag of its own. 2049 */ 2050 /* This case represents an initialization collision. */ 2051 static enum sctp_disposition sctp_sf_do_dupcook_c( 2052 struct net *net, 2053 const struct sctp_endpoint *ep, 2054 const struct sctp_association *asoc, 2055 struct sctp_chunk *chunk, 2056 struct sctp_cmd_seq *commands, 2057 struct sctp_association *new_asoc) 2058 { 2059 /* The cookie should be silently discarded. 2060 * The endpoint SHOULD NOT change states and should leave 2061 * any timers running. 2062 */ 2063 return SCTP_DISPOSITION_DISCARD; 2064 } 2065 2066 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') 2067 * 2068 * Section 5.2.4 2069 * 2070 * D) When both local and remote tags match the endpoint should always 2071 * enter the ESTABLISHED state, if it has not already done so. 2072 */ 2073 /* This case represents an initialization collision. */ 2074 static enum sctp_disposition sctp_sf_do_dupcook_d( 2075 struct net *net, 2076 const struct sctp_endpoint *ep, 2077 const struct sctp_association *asoc, 2078 struct sctp_chunk *chunk, 2079 struct sctp_cmd_seq *commands, 2080 struct sctp_association *new_asoc) 2081 { 2082 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL, *auth_ev = NULL; 2083 struct sctp_chunk *repl; 2084 2085 /* Clarification from Implementor's Guide: 2086 * D) When both local and remote tags match the endpoint should 2087 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. 2088 * It should stop any cookie timer that may be running and send 2089 * a COOKIE ACK. 2090 */ 2091 2092 if (!sctp_auth_chunk_verify(net, chunk, asoc)) 2093 return SCTP_DISPOSITION_DISCARD; 2094 2095 /* Don't accidentally move back into established state. */ 2096 if (asoc->state < SCTP_STATE_ESTABLISHED) { 2097 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2098 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2099 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2100 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 2101 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 2102 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, 2103 SCTP_NULL()); 2104 2105 /* RFC 2960 5.1 Normal Establishment of an Association 2106 * 2107 * D) IMPLEMENTATION NOTE: An implementation may choose 2108 * to send the Communication Up notification to the 2109 * SCTP user upon reception of a valid COOKIE 2110 * ECHO chunk. 2111 */ 2112 ev = sctp_ulpevent_make_assoc_change(asoc, 0, 2113 SCTP_COMM_UP, 0, 2114 asoc->c.sinit_num_ostreams, 2115 asoc->c.sinit_max_instreams, 2116 NULL, GFP_ATOMIC); 2117 if (!ev) 2118 goto nomem; 2119 2120 /* Sockets API Draft Section 5.3.1.6 2121 * When a peer sends a Adaptation Layer Indication parameter, 2122 * SCTP delivers this notification to inform the application 2123 * that of the peers requested adaptation layer. 2124 */ 2125 if (asoc->peer.adaptation_ind) { 2126 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc, 2127 GFP_ATOMIC); 2128 if (!ai_ev) 2129 goto nomem; 2130 2131 } 2132 2133 if (!asoc->peer.auth_capable) { 2134 auth_ev = sctp_ulpevent_make_authkey(asoc, 0, 2135 SCTP_AUTH_NO_AUTH, 2136 GFP_ATOMIC); 2137 if (!auth_ev) 2138 goto nomem; 2139 } 2140 } 2141 2142 repl = sctp_make_cookie_ack(asoc, chunk); 2143 if (!repl) 2144 goto nomem; 2145 2146 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 2147 2148 if (ev) 2149 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2150 SCTP_ULPEVENT(ev)); 2151 if (ai_ev) 2152 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2153 SCTP_ULPEVENT(ai_ev)); 2154 if (auth_ev) 2155 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2156 SCTP_ULPEVENT(auth_ev)); 2157 2158 return SCTP_DISPOSITION_CONSUME; 2159 2160 nomem: 2161 if (auth_ev) 2162 sctp_ulpevent_free(auth_ev); 2163 if (ai_ev) 2164 sctp_ulpevent_free(ai_ev); 2165 if (ev) 2166 sctp_ulpevent_free(ev); 2167 return SCTP_DISPOSITION_NOMEM; 2168 } 2169 2170 /* 2171 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying 2172 * chunk was retransmitted and then delayed in the network. 2173 * 2174 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists 2175 * 2176 * Verification Tag: None. Do cookie validation. 2177 * 2178 * Inputs 2179 * (endpoint, asoc, chunk) 2180 * 2181 * Outputs 2182 * (asoc, reply_msg, msg_up, timers, counters) 2183 * 2184 * The return value is the disposition of the chunk. 2185 */ 2186 enum sctp_disposition sctp_sf_do_5_2_4_dupcook( 2187 struct net *net, 2188 const struct sctp_endpoint *ep, 2189 const struct sctp_association *asoc, 2190 const union sctp_subtype type, 2191 void *arg, 2192 struct sctp_cmd_seq *commands) 2193 { 2194 struct sctp_association *new_asoc; 2195 struct sctp_chunk *chunk = arg; 2196 enum sctp_disposition retval; 2197 struct sctp_chunk *err_chk_p; 2198 int error = 0; 2199 char action; 2200 2201 /* Make sure that the chunk has a valid length from the protocol 2202 * perspective. In this case check to make sure we have at least 2203 * enough for the chunk header. Cookie length verification is 2204 * done later. 2205 */ 2206 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 2207 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2208 commands); 2209 2210 /* "Decode" the chunk. We have no optional parameters so we 2211 * are in good shape. 2212 */ 2213 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; 2214 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 2215 sizeof(struct sctp_chunkhdr))) 2216 goto nomem; 2217 2218 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie 2219 * of a duplicate COOKIE ECHO match the Verification Tags of the 2220 * current association, consider the State Cookie valid even if 2221 * the lifespan is exceeded. 2222 */ 2223 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 2224 &err_chk_p); 2225 2226 /* FIXME: 2227 * If the re-build failed, what is the proper error path 2228 * from here? 2229 * 2230 * [We should abort the association. --piggy] 2231 */ 2232 if (!new_asoc) { 2233 /* FIXME: Several errors are possible. A bad cookie should 2234 * be silently discarded, but think about logging it too. 2235 */ 2236 switch (error) { 2237 case -SCTP_IERROR_NOMEM: 2238 goto nomem; 2239 2240 case -SCTP_IERROR_STALE_COOKIE: 2241 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 2242 err_chk_p); 2243 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2244 case -SCTP_IERROR_BAD_SIG: 2245 default: 2246 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2247 } 2248 } 2249 2250 /* Update socket peer label if first association. */ 2251 if (security_sctp_assoc_request((struct sctp_endpoint *)ep, 2252 chunk->skb)) { 2253 sctp_association_free(new_asoc); 2254 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2255 } 2256 2257 /* Set temp so that it won't be added into hashtable */ 2258 new_asoc->temp = 1; 2259 2260 /* Compare the tie_tag in cookie with the verification tag of 2261 * current association. 2262 */ 2263 action = sctp_tietags_compare(new_asoc, asoc); 2264 2265 switch (action) { 2266 case 'A': /* Association restart. */ 2267 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands, 2268 new_asoc); 2269 break; 2270 2271 case 'B': /* Collision case B. */ 2272 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands, 2273 new_asoc); 2274 break; 2275 2276 case 'C': /* Collision case C. */ 2277 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands, 2278 new_asoc); 2279 break; 2280 2281 case 'D': /* Collision case D. */ 2282 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands, 2283 new_asoc); 2284 break; 2285 2286 default: /* Discard packet for all others. */ 2287 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2288 break; 2289 } 2290 2291 /* Delete the temporary new association. */ 2292 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc)); 2293 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 2294 2295 /* Restore association pointer to provide SCTP command interpreter 2296 * with a valid context in case it needs to manipulate 2297 * the queues */ 2298 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, 2299 SCTP_ASOC((struct sctp_association *)asoc)); 2300 2301 return retval; 2302 2303 nomem: 2304 return SCTP_DISPOSITION_NOMEM; 2305 } 2306 2307 /* 2308 * Process an ABORT. (SHUTDOWN-PENDING state) 2309 * 2310 * See sctp_sf_do_9_1_abort(). 2311 */ 2312 enum sctp_disposition sctp_sf_shutdown_pending_abort( 2313 struct net *net, 2314 const struct sctp_endpoint *ep, 2315 const struct sctp_association *asoc, 2316 const union sctp_subtype type, 2317 void *arg, 2318 struct sctp_cmd_seq *commands) 2319 { 2320 struct sctp_chunk *chunk = arg; 2321 2322 if (!sctp_vtag_verify_either(chunk, asoc)) 2323 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2324 2325 /* Make sure that the ABORT chunk has a valid length. 2326 * Since this is an ABORT chunk, we have to discard it 2327 * because of the following text: 2328 * RFC 2960, Section 3.3.7 2329 * If an endpoint receives an ABORT with a format error or for an 2330 * association that doesn't exist, it MUST silently discard it. 2331 * Because the length is "invalid", we can't really discard just 2332 * as we do not know its true length. So, to be safe, discard the 2333 * packet. 2334 */ 2335 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2336 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2337 2338 /* ADD-IP: Special case for ABORT chunks 2339 * F4) One special consideration is that ABORT Chunks arriving 2340 * destined to the IP address being deleted MUST be 2341 * ignored (see Section 5.3.1 for further details). 2342 */ 2343 if (SCTP_ADDR_DEL == 2344 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2345 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2346 2347 if (!sctp_err_chunk_valid(chunk)) 2348 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2349 2350 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2351 } 2352 2353 /* 2354 * Process an ABORT. (SHUTDOWN-SENT state) 2355 * 2356 * See sctp_sf_do_9_1_abort(). 2357 */ 2358 enum sctp_disposition sctp_sf_shutdown_sent_abort( 2359 struct net *net, 2360 const struct sctp_endpoint *ep, 2361 const struct sctp_association *asoc, 2362 const union sctp_subtype type, 2363 void *arg, 2364 struct sctp_cmd_seq *commands) 2365 { 2366 struct sctp_chunk *chunk = arg; 2367 2368 if (!sctp_vtag_verify_either(chunk, asoc)) 2369 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2370 2371 /* Make sure that the ABORT chunk has a valid length. 2372 * Since this is an ABORT chunk, we have to discard it 2373 * because of the following text: 2374 * RFC 2960, Section 3.3.7 2375 * If an endpoint receives an ABORT with a format error or for an 2376 * association that doesn't exist, it MUST silently discard it. 2377 * Because the length is "invalid", we can't really discard just 2378 * as we do not know its true length. So, to be safe, discard the 2379 * packet. 2380 */ 2381 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2382 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2383 2384 /* ADD-IP: Special case for ABORT chunks 2385 * F4) One special consideration is that ABORT Chunks arriving 2386 * destined to the IP address being deleted MUST be 2387 * ignored (see Section 5.3.1 for further details). 2388 */ 2389 if (SCTP_ADDR_DEL == 2390 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2391 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2392 2393 if (!sctp_err_chunk_valid(chunk)) 2394 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2395 2396 /* Stop the T2-shutdown timer. */ 2397 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2398 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2399 2400 /* Stop the T5-shutdown guard timer. */ 2401 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2402 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2403 2404 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2405 } 2406 2407 /* 2408 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2409 * 2410 * See sctp_sf_do_9_1_abort(). 2411 */ 2412 enum sctp_disposition sctp_sf_shutdown_ack_sent_abort( 2413 struct net *net, 2414 const struct sctp_endpoint *ep, 2415 const struct sctp_association *asoc, 2416 const union sctp_subtype type, 2417 void *arg, 2418 struct sctp_cmd_seq *commands) 2419 { 2420 /* The same T2 timer, so we should be able to use 2421 * common function with the SHUTDOWN-SENT state. 2422 */ 2423 return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands); 2424 } 2425 2426 /* 2427 * Handle an Error received in COOKIE_ECHOED state. 2428 * 2429 * Only handle the error type of stale COOKIE Error, the other errors will 2430 * be ignored. 2431 * 2432 * Inputs 2433 * (endpoint, asoc, chunk) 2434 * 2435 * Outputs 2436 * (asoc, reply_msg, msg_up, timers, counters) 2437 * 2438 * The return value is the disposition of the chunk. 2439 */ 2440 enum sctp_disposition sctp_sf_cookie_echoed_err( 2441 struct net *net, 2442 const struct sctp_endpoint *ep, 2443 const struct sctp_association *asoc, 2444 const union sctp_subtype type, 2445 void *arg, 2446 struct sctp_cmd_seq *commands) 2447 { 2448 struct sctp_chunk *chunk = arg; 2449 struct sctp_errhdr *err; 2450 2451 if (!sctp_vtag_verify(chunk, asoc)) 2452 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2453 2454 /* Make sure that the ERROR chunk has a valid length. 2455 * The parameter walking depends on this as well. 2456 */ 2457 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk))) 2458 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2459 commands); 2460 2461 /* Process the error here */ 2462 /* FUTURE FIXME: When PR-SCTP related and other optional 2463 * parms are emitted, this will have to change to handle multiple 2464 * errors. 2465 */ 2466 sctp_walk_errors(err, chunk->chunk_hdr) { 2467 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2468 return sctp_sf_do_5_2_6_stale(net, ep, asoc, type, 2469 arg, commands); 2470 } 2471 2472 /* It is possible to have malformed error causes, and that 2473 * will cause us to end the walk early. However, since 2474 * we are discarding the packet, there should be no adverse 2475 * affects. 2476 */ 2477 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2478 } 2479 2480 /* 2481 * Handle a Stale COOKIE Error 2482 * 2483 * Section: 5.2.6 Handle Stale COOKIE Error 2484 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2485 * one of the following three alternatives. 2486 * ... 2487 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2488 * Preservative parameter requesting an extension to the lifetime of 2489 * the State Cookie. When calculating the time extension, an 2490 * implementation SHOULD use the RTT information measured based on the 2491 * previous COOKIE ECHO / ERROR exchange, and should add no more 2492 * than 1 second beyond the measured RTT, due to long State Cookie 2493 * lifetimes making the endpoint more subject to a replay attack. 2494 * 2495 * Verification Tag: Not explicit, but safe to ignore. 2496 * 2497 * Inputs 2498 * (endpoint, asoc, chunk) 2499 * 2500 * Outputs 2501 * (asoc, reply_msg, msg_up, timers, counters) 2502 * 2503 * The return value is the disposition of the chunk. 2504 */ 2505 static enum sctp_disposition sctp_sf_do_5_2_6_stale( 2506 struct net *net, 2507 const struct sctp_endpoint *ep, 2508 const struct sctp_association *asoc, 2509 const union sctp_subtype type, 2510 void *arg, 2511 struct sctp_cmd_seq *commands) 2512 { 2513 int attempts = asoc->init_err_counter + 1; 2514 struct sctp_chunk *chunk = arg, *reply; 2515 struct sctp_cookie_preserve_param bht; 2516 struct sctp_bind_addr *bp; 2517 struct sctp_errhdr *err; 2518 u32 stale; 2519 2520 if (attempts > asoc->max_init_attempts) { 2521 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 2522 SCTP_ERROR(ETIMEDOUT)); 2523 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2524 SCTP_PERR(SCTP_ERROR_STALE_COOKIE)); 2525 return SCTP_DISPOSITION_DELETE_TCB; 2526 } 2527 2528 err = (struct sctp_errhdr *)(chunk->skb->data); 2529 2530 /* When calculating the time extension, an implementation 2531 * SHOULD use the RTT information measured based on the 2532 * previous COOKIE ECHO / ERROR exchange, and should add no 2533 * more than 1 second beyond the measured RTT, due to long 2534 * State Cookie lifetimes making the endpoint more subject to 2535 * a replay attack. 2536 * Measure of Staleness's unit is usec. (1/1000000 sec) 2537 * Suggested Cookie Life-span Increment's unit is msec. 2538 * (1/1000 sec) 2539 * In general, if you use the suggested cookie life, the value 2540 * found in the field of measure of staleness should be doubled 2541 * to give ample time to retransmit the new cookie and thus 2542 * yield a higher probability of success on the reattempt. 2543 */ 2544 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err))); 2545 stale = (stale * 2) / 1000; 2546 2547 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2548 bht.param_hdr.length = htons(sizeof(bht)); 2549 bht.lifespan_increment = htonl(stale); 2550 2551 /* Build that new INIT chunk. */ 2552 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2553 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2554 if (!reply) 2555 goto nomem; 2556 2557 sctp_addto_chunk(reply, sizeof(bht), &bht); 2558 2559 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2560 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2561 2562 /* Stop pending T3-rtx and heartbeat timers */ 2563 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2564 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2565 2566 /* Delete non-primary peer ip addresses since we are transitioning 2567 * back to the COOKIE-WAIT state 2568 */ 2569 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2570 2571 /* If we've sent any data bundled with COOKIE-ECHO we will need to 2572 * resend 2573 */ 2574 sctp_add_cmd_sf(commands, SCTP_CMD_T1_RETRAN, 2575 SCTP_TRANSPORT(asoc->peer.primary_path)); 2576 2577 /* Cast away the const modifier, as we want to just 2578 * rerun it through as a sideffect. 2579 */ 2580 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2581 2582 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2583 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2584 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2585 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2586 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2587 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2588 2589 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2590 2591 return SCTP_DISPOSITION_CONSUME; 2592 2593 nomem: 2594 return SCTP_DISPOSITION_NOMEM; 2595 } 2596 2597 /* 2598 * Process an ABORT. 2599 * 2600 * Section: 9.1 2601 * After checking the Verification Tag, the receiving endpoint shall 2602 * remove the association from its record, and shall report the 2603 * termination to its upper layer. 2604 * 2605 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2606 * B) Rules for packet carrying ABORT: 2607 * 2608 * - The endpoint shall always fill in the Verification Tag field of the 2609 * outbound packet with the destination endpoint's tag value if it 2610 * is known. 2611 * 2612 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2613 * MUST follow the procedure described in Section 8.4. 2614 * 2615 * - The receiver MUST accept the packet if the Verification Tag 2616 * matches either its own tag, OR the tag of its peer. Otherwise, the 2617 * receiver MUST silently discard the packet and take no further 2618 * action. 2619 * 2620 * Inputs 2621 * (endpoint, asoc, chunk) 2622 * 2623 * Outputs 2624 * (asoc, reply_msg, msg_up, timers, counters) 2625 * 2626 * The return value is the disposition of the chunk. 2627 */ 2628 enum sctp_disposition sctp_sf_do_9_1_abort( 2629 struct net *net, 2630 const struct sctp_endpoint *ep, 2631 const struct sctp_association *asoc, 2632 const union sctp_subtype type, 2633 void *arg, 2634 struct sctp_cmd_seq *commands) 2635 { 2636 struct sctp_chunk *chunk = arg; 2637 2638 if (!sctp_vtag_verify_either(chunk, asoc)) 2639 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2640 2641 /* Make sure that the ABORT chunk has a valid length. 2642 * Since this is an ABORT chunk, we have to discard it 2643 * because of the following text: 2644 * RFC 2960, Section 3.3.7 2645 * If an endpoint receives an ABORT with a format error or for an 2646 * association that doesn't exist, it MUST silently discard it. 2647 * Because the length is "invalid", we can't really discard just 2648 * as we do not know its true length. So, to be safe, discard the 2649 * packet. 2650 */ 2651 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2652 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2653 2654 /* ADD-IP: Special case for ABORT chunks 2655 * F4) One special consideration is that ABORT Chunks arriving 2656 * destined to the IP address being deleted MUST be 2657 * ignored (see Section 5.3.1 for further details). 2658 */ 2659 if (SCTP_ADDR_DEL == 2660 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2661 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 2662 2663 if (!sctp_err_chunk_valid(chunk)) 2664 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2665 2666 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2667 } 2668 2669 static enum sctp_disposition __sctp_sf_do_9_1_abort( 2670 struct net *net, 2671 const struct sctp_endpoint *ep, 2672 const struct sctp_association *asoc, 2673 const union sctp_subtype type, 2674 void *arg, 2675 struct sctp_cmd_seq *commands) 2676 { 2677 __be16 error = SCTP_ERROR_NO_ERROR; 2678 struct sctp_chunk *chunk = arg; 2679 unsigned int len; 2680 2681 /* See if we have an error cause code in the chunk. */ 2682 len = ntohs(chunk->chunk_hdr->length); 2683 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2684 error = ((struct sctp_errhdr *)chunk->skb->data)->cause; 2685 2686 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET)); 2687 /* ASSOC_FAILED will DELETE_TCB. */ 2688 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error)); 2689 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2690 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 2691 2692 return SCTP_DISPOSITION_ABORT; 2693 } 2694 2695 /* 2696 * Process an ABORT. (COOKIE-WAIT state) 2697 * 2698 * See sctp_sf_do_9_1_abort() above. 2699 */ 2700 enum sctp_disposition sctp_sf_cookie_wait_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 if (!sctp_vtag_verify_either(chunk, asoc)) 2713 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2714 2715 /* Make sure that the ABORT chunk has a valid length. 2716 * Since this is an ABORT chunk, we have to discard it 2717 * because of the following text: 2718 * RFC 2960, Section 3.3.7 2719 * If an endpoint receives an ABORT with a format error or for an 2720 * association that doesn't exist, it MUST silently discard it. 2721 * Because the length is "invalid", we can't really discard just 2722 * as we do not know its true length. So, to be safe, discard the 2723 * packet. 2724 */ 2725 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2726 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2727 2728 /* See if we have an error cause code in the chunk. */ 2729 len = ntohs(chunk->chunk_hdr->length); 2730 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2731 error = ((struct sctp_errhdr *)chunk->skb->data)->cause; 2732 2733 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc, 2734 chunk->transport); 2735 } 2736 2737 /* 2738 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2739 */ 2740 enum sctp_disposition sctp_sf_cookie_wait_icmp_abort( 2741 struct net *net, 2742 const struct sctp_endpoint *ep, 2743 const struct sctp_association *asoc, 2744 const union sctp_subtype type, 2745 void *arg, 2746 struct sctp_cmd_seq *commands) 2747 { 2748 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR, 2749 ENOPROTOOPT, asoc, 2750 (struct sctp_transport *)arg); 2751 } 2752 2753 /* 2754 * Process an ABORT. (COOKIE-ECHOED state) 2755 */ 2756 enum sctp_disposition sctp_sf_cookie_echoed_abort( 2757 struct net *net, 2758 const struct sctp_endpoint *ep, 2759 const struct sctp_association *asoc, 2760 const union sctp_subtype type, 2761 void *arg, 2762 struct sctp_cmd_seq *commands) 2763 { 2764 /* There is a single T1 timer, so we should be able to use 2765 * common function with the COOKIE-WAIT state. 2766 */ 2767 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands); 2768 } 2769 2770 /* 2771 * Stop T1 timer and abort association with "INIT failed". 2772 * 2773 * This is common code called by several sctp_sf_*_abort() functions above. 2774 */ 2775 static enum sctp_disposition sctp_stop_t1_and_abort( 2776 struct net *net, 2777 struct sctp_cmd_seq *commands, 2778 __be16 error, int sk_err, 2779 const struct sctp_association *asoc, 2780 struct sctp_transport *transport) 2781 { 2782 pr_debug("%s: ABORT received (INIT)\n", __func__); 2783 2784 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2785 SCTP_STATE(SCTP_STATE_CLOSED)); 2786 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2787 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2788 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2789 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err)); 2790 /* CMD_INIT_FAILED will DELETE_TCB. */ 2791 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2792 SCTP_PERR(error)); 2793 2794 return SCTP_DISPOSITION_ABORT; 2795 } 2796 2797 /* 2798 * sctp_sf_do_9_2_shut 2799 * 2800 * Section: 9.2 2801 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2802 * - enter the SHUTDOWN-RECEIVED state, 2803 * 2804 * - stop accepting new data from its SCTP user 2805 * 2806 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2807 * that all its outstanding DATA chunks have been received by the 2808 * SHUTDOWN sender. 2809 * 2810 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2811 * send a SHUTDOWN in response to a ULP request. And should discard 2812 * subsequent SHUTDOWN chunks. 2813 * 2814 * If there are still outstanding DATA chunks left, the SHUTDOWN 2815 * receiver shall continue to follow normal data transmission 2816 * procedures defined in Section 6 until all outstanding DATA chunks 2817 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2818 * new data from its SCTP user. 2819 * 2820 * Verification Tag: 8.5 Verification Tag [Normal verification] 2821 * 2822 * Inputs 2823 * (endpoint, asoc, chunk) 2824 * 2825 * Outputs 2826 * (asoc, reply_msg, msg_up, timers, counters) 2827 * 2828 * The return value is the disposition of the chunk. 2829 */ 2830 enum sctp_disposition sctp_sf_do_9_2_shutdown( 2831 struct net *net, 2832 const struct sctp_endpoint *ep, 2833 const struct sctp_association *asoc, 2834 const union sctp_subtype type, 2835 void *arg, 2836 struct sctp_cmd_seq *commands) 2837 { 2838 enum sctp_disposition disposition; 2839 struct sctp_chunk *chunk = arg; 2840 struct sctp_shutdownhdr *sdh; 2841 struct sctp_ulpevent *ev; 2842 __u32 ctsn; 2843 2844 if (!sctp_vtag_verify(chunk, asoc)) 2845 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2846 2847 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2848 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk))) 2849 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2850 commands); 2851 2852 /* Convert the elaborate header. */ 2853 sdh = (struct sctp_shutdownhdr *)chunk->skb->data; 2854 skb_pull(chunk->skb, sizeof(*sdh)); 2855 chunk->subh.shutdown_hdr = sdh; 2856 ctsn = ntohl(sdh->cum_tsn_ack); 2857 2858 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2859 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2860 asoc->ctsn_ack_point); 2861 2862 return SCTP_DISPOSITION_DISCARD; 2863 } 2864 2865 /* If Cumulative TSN Ack beyond the max tsn currently 2866 * send, terminating the association and respond to the 2867 * sender with an ABORT. 2868 */ 2869 if (!TSN_lt(ctsn, asoc->next_tsn)) 2870 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2871 2872 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2873 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2874 * inform the application that it should cease sending data. 2875 */ 2876 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2877 if (!ev) { 2878 disposition = SCTP_DISPOSITION_NOMEM; 2879 goto out; 2880 } 2881 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2882 2883 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2884 * - enter the SHUTDOWN-RECEIVED state, 2885 * - stop accepting new data from its SCTP user 2886 * 2887 * [This is implicit in the new state.] 2888 */ 2889 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2890 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2891 disposition = SCTP_DISPOSITION_CONSUME; 2892 2893 if (sctp_outq_is_empty(&asoc->outqueue)) { 2894 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type, 2895 arg, commands); 2896 } 2897 2898 if (SCTP_DISPOSITION_NOMEM == disposition) 2899 goto out; 2900 2901 /* - verify, by checking the Cumulative TSN Ack field of the 2902 * chunk, that all its outstanding DATA chunks have been 2903 * received by the SHUTDOWN sender. 2904 */ 2905 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2906 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2907 2908 out: 2909 return disposition; 2910 } 2911 2912 /* 2913 * sctp_sf_do_9_2_shut_ctsn 2914 * 2915 * Once an endpoint has reached the SHUTDOWN-RECEIVED state, 2916 * it MUST NOT send a SHUTDOWN in response to a ULP request. 2917 * The Cumulative TSN Ack of the received SHUTDOWN chunk 2918 * MUST be processed. 2919 */ 2920 enum sctp_disposition sctp_sf_do_9_2_shut_ctsn( 2921 struct net *net, 2922 const struct sctp_endpoint *ep, 2923 const struct sctp_association *asoc, 2924 const union sctp_subtype type, 2925 void *arg, 2926 struct sctp_cmd_seq *commands) 2927 { 2928 struct sctp_chunk *chunk = arg; 2929 struct sctp_shutdownhdr *sdh; 2930 __u32 ctsn; 2931 2932 if (!sctp_vtag_verify(chunk, asoc)) 2933 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2934 2935 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2936 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk))) 2937 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2938 commands); 2939 2940 sdh = (struct sctp_shutdownhdr *)chunk->skb->data; 2941 ctsn = ntohl(sdh->cum_tsn_ack); 2942 2943 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2944 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2945 asoc->ctsn_ack_point); 2946 2947 return SCTP_DISPOSITION_DISCARD; 2948 } 2949 2950 /* If Cumulative TSN Ack beyond the max tsn currently 2951 * send, terminating the association and respond to the 2952 * sender with an ABORT. 2953 */ 2954 if (!TSN_lt(ctsn, asoc->next_tsn)) 2955 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2956 2957 /* verify, by checking the Cumulative TSN Ack field of the 2958 * chunk, that all its outstanding DATA chunks have been 2959 * received by the SHUTDOWN sender. 2960 */ 2961 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2962 SCTP_BE32(sdh->cum_tsn_ack)); 2963 2964 return SCTP_DISPOSITION_CONSUME; 2965 } 2966 2967 /* RFC 2960 9.2 2968 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2969 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 2970 * transport addresses (either in the IP addresses or in the INIT chunk) 2971 * that belong to this association, it should discard the INIT chunk and 2972 * retransmit the SHUTDOWN ACK chunk. 2973 */ 2974 enum sctp_disposition sctp_sf_do_9_2_reshutack( 2975 struct net *net, 2976 const struct sctp_endpoint *ep, 2977 const struct sctp_association *asoc, 2978 const union sctp_subtype type, 2979 void *arg, 2980 struct sctp_cmd_seq *commands) 2981 { 2982 struct sctp_chunk *chunk = arg; 2983 struct sctp_chunk *reply; 2984 2985 /* Make sure that the chunk has a valid length */ 2986 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 2987 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2988 commands); 2989 2990 /* Since we are not going to really process this INIT, there 2991 * is no point in verifying chunk boundaries. Just generate 2992 * the SHUTDOWN ACK. 2993 */ 2994 reply = sctp_make_shutdown_ack(asoc, chunk); 2995 if (NULL == reply) 2996 goto nomem; 2997 2998 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 2999 * the T2-SHUTDOWN timer. 3000 */ 3001 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 3002 3003 /* and restart the T2-shutdown timer. */ 3004 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3005 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3006 3007 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3008 3009 return SCTP_DISPOSITION_CONSUME; 3010 nomem: 3011 return SCTP_DISPOSITION_NOMEM; 3012 } 3013 3014 /* 3015 * sctp_sf_do_ecn_cwr 3016 * 3017 * Section: Appendix A: Explicit Congestion Notification 3018 * 3019 * CWR: 3020 * 3021 * RFC 2481 details a specific bit for a sender to send in the header of 3022 * its next outbound TCP segment to indicate to its peer that it has 3023 * reduced its congestion window. This is termed the CWR bit. For 3024 * SCTP the same indication is made by including the CWR chunk. 3025 * This chunk contains one data element, i.e. the TSN number that 3026 * was sent in the ECNE chunk. This element represents the lowest 3027 * TSN number in the datagram that was originally marked with the 3028 * CE bit. 3029 * 3030 * Verification Tag: 8.5 Verification Tag [Normal verification] 3031 * Inputs 3032 * (endpoint, asoc, chunk) 3033 * 3034 * Outputs 3035 * (asoc, reply_msg, msg_up, timers, counters) 3036 * 3037 * The return value is the disposition of the chunk. 3038 */ 3039 enum sctp_disposition sctp_sf_do_ecn_cwr(struct net *net, 3040 const struct sctp_endpoint *ep, 3041 const struct sctp_association *asoc, 3042 const union sctp_subtype type, 3043 void *arg, 3044 struct sctp_cmd_seq *commands) 3045 { 3046 struct sctp_chunk *chunk = arg; 3047 struct sctp_cwrhdr *cwr; 3048 u32 lowest_tsn; 3049 3050 if (!sctp_vtag_verify(chunk, asoc)) 3051 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3052 3053 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk))) 3054 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3055 commands); 3056 3057 cwr = (struct sctp_cwrhdr *)chunk->skb->data; 3058 skb_pull(chunk->skb, sizeof(*cwr)); 3059 3060 lowest_tsn = ntohl(cwr->lowest_tsn); 3061 3062 /* Does this CWR ack the last sent congestion notification? */ 3063 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) { 3064 /* Stop sending ECNE. */ 3065 sctp_add_cmd_sf(commands, 3066 SCTP_CMD_ECN_CWR, 3067 SCTP_U32(lowest_tsn)); 3068 } 3069 return SCTP_DISPOSITION_CONSUME; 3070 } 3071 3072 /* 3073 * sctp_sf_do_ecne 3074 * 3075 * Section: Appendix A: Explicit Congestion Notification 3076 * 3077 * ECN-Echo 3078 * 3079 * RFC 2481 details a specific bit for a receiver to send back in its 3080 * TCP acknowledgements to notify the sender of the Congestion 3081 * Experienced (CE) bit having arrived from the network. For SCTP this 3082 * same indication is made by including the ECNE chunk. This chunk 3083 * contains one data element, i.e. the lowest TSN associated with the IP 3084 * datagram marked with the CE bit..... 3085 * 3086 * Verification Tag: 8.5 Verification Tag [Normal verification] 3087 * Inputs 3088 * (endpoint, asoc, chunk) 3089 * 3090 * Outputs 3091 * (asoc, reply_msg, msg_up, timers, counters) 3092 * 3093 * The return value is the disposition of the chunk. 3094 */ 3095 enum sctp_disposition sctp_sf_do_ecne(struct net *net, 3096 const struct sctp_endpoint *ep, 3097 const struct sctp_association *asoc, 3098 const union sctp_subtype type, 3099 void *arg, struct sctp_cmd_seq *commands) 3100 { 3101 struct sctp_chunk *chunk = arg; 3102 struct sctp_ecnehdr *ecne; 3103 3104 if (!sctp_vtag_verify(chunk, asoc)) 3105 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3106 3107 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk))) 3108 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3109 commands); 3110 3111 ecne = (struct sctp_ecnehdr *)chunk->skb->data; 3112 skb_pull(chunk->skb, sizeof(*ecne)); 3113 3114 /* If this is a newer ECNE than the last CWR packet we sent out */ 3115 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 3116 SCTP_U32(ntohl(ecne->lowest_tsn))); 3117 3118 return SCTP_DISPOSITION_CONSUME; 3119 } 3120 3121 /* 3122 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 3123 * 3124 * The SCTP endpoint MUST always acknowledge the reception of each valid 3125 * DATA chunk. 3126 * 3127 * The guidelines on delayed acknowledgement algorithm specified in 3128 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 3129 * acknowledgement SHOULD be generated for at least every second packet 3130 * (not every second DATA chunk) received, and SHOULD be generated within 3131 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 3132 * situations it may be beneficial for an SCTP transmitter to be more 3133 * conservative than the algorithms detailed in this document allow. 3134 * However, an SCTP transmitter MUST NOT be more aggressive than the 3135 * following algorithms allow. 3136 * 3137 * A SCTP receiver MUST NOT generate more than one SACK for every 3138 * incoming packet, other than to update the offered window as the 3139 * receiving application consumes new data. 3140 * 3141 * Verification Tag: 8.5 Verification Tag [Normal verification] 3142 * 3143 * Inputs 3144 * (endpoint, asoc, chunk) 3145 * 3146 * Outputs 3147 * (asoc, reply_msg, msg_up, timers, counters) 3148 * 3149 * The return value is the disposition of the chunk. 3150 */ 3151 enum sctp_disposition sctp_sf_eat_data_6_2(struct net *net, 3152 const struct sctp_endpoint *ep, 3153 const struct sctp_association *asoc, 3154 const union sctp_subtype type, 3155 void *arg, 3156 struct sctp_cmd_seq *commands) 3157 { 3158 union sctp_arg force = SCTP_NOFORCE(); 3159 struct sctp_chunk *chunk = arg; 3160 int error; 3161 3162 if (!sctp_vtag_verify(chunk, asoc)) { 3163 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3164 SCTP_NULL()); 3165 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3166 } 3167 3168 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream))) 3169 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3170 commands); 3171 3172 error = sctp_eat_data(asoc, chunk, commands); 3173 switch (error) { 3174 case SCTP_IERROR_NO_ERROR: 3175 break; 3176 case SCTP_IERROR_HIGH_TSN: 3177 case SCTP_IERROR_BAD_STREAM: 3178 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3179 goto discard_noforce; 3180 case SCTP_IERROR_DUP_TSN: 3181 case SCTP_IERROR_IGNORE_TSN: 3182 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3183 goto discard_force; 3184 case SCTP_IERROR_NO_DATA: 3185 return SCTP_DISPOSITION_ABORT; 3186 case SCTP_IERROR_PROTO_VIOLATION: 3187 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3188 (u8 *)chunk->subh.data_hdr, 3189 sctp_datahdr_len(&asoc->stream)); 3190 default: 3191 BUG(); 3192 } 3193 3194 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM) 3195 force = SCTP_FORCE(); 3196 3197 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 3198 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3199 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3200 } 3201 3202 /* If this is the last chunk in a packet, we need to count it 3203 * toward sack generation. Note that we need to SACK every 3204 * OTHER packet containing data chunks, EVEN IF WE DISCARD 3205 * THEM. We elect to NOT generate SACK's if the chunk fails 3206 * the verification tag test. 3207 * 3208 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3209 * 3210 * The SCTP endpoint MUST always acknowledge the reception of 3211 * each valid DATA chunk. 3212 * 3213 * The guidelines on delayed acknowledgement algorithm 3214 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 3215 * Specifically, an acknowledgement SHOULD be generated for at 3216 * least every second packet (not every second DATA chunk) 3217 * received, and SHOULD be generated within 200 ms of the 3218 * arrival of any unacknowledged DATA chunk. In some 3219 * situations it may be beneficial for an SCTP transmitter to 3220 * be more conservative than the algorithms detailed in this 3221 * document allow. However, an SCTP transmitter MUST NOT be 3222 * more aggressive than the following algorithms allow. 3223 */ 3224 if (chunk->end_of_packet) 3225 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3226 3227 return SCTP_DISPOSITION_CONSUME; 3228 3229 discard_force: 3230 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3231 * 3232 * When a packet arrives with duplicate DATA chunk(s) and with 3233 * no new DATA chunk(s), the endpoint MUST immediately send a 3234 * SACK with no delay. If a packet arrives with duplicate 3235 * DATA chunk(s) bundled with new DATA chunks, the endpoint 3236 * MAY immediately send a SACK. Normally receipt of duplicate 3237 * DATA chunks will occur when the original SACK chunk was lost 3238 * and the peer's RTO has expired. The duplicate TSN number(s) 3239 * SHOULD be reported in the SACK as duplicate. 3240 */ 3241 /* In our case, we split the MAY SACK advice up whether or not 3242 * the last chunk is a duplicate.' 3243 */ 3244 if (chunk->end_of_packet) 3245 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3246 return SCTP_DISPOSITION_DISCARD; 3247 3248 discard_noforce: 3249 if (chunk->end_of_packet) 3250 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3251 3252 return SCTP_DISPOSITION_DISCARD; 3253 } 3254 3255 /* 3256 * sctp_sf_eat_data_fast_4_4 3257 * 3258 * Section: 4 (4) 3259 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 3260 * DATA chunks without delay. 3261 * 3262 * Verification Tag: 8.5 Verification Tag [Normal verification] 3263 * Inputs 3264 * (endpoint, asoc, chunk) 3265 * 3266 * Outputs 3267 * (asoc, reply_msg, msg_up, timers, counters) 3268 * 3269 * The return value is the disposition of the chunk. 3270 */ 3271 enum sctp_disposition sctp_sf_eat_data_fast_4_4( 3272 struct net *net, 3273 const struct sctp_endpoint *ep, 3274 const struct sctp_association *asoc, 3275 const union sctp_subtype type, 3276 void *arg, 3277 struct sctp_cmd_seq *commands) 3278 { 3279 struct sctp_chunk *chunk = arg; 3280 int error; 3281 3282 if (!sctp_vtag_verify(chunk, asoc)) { 3283 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3284 SCTP_NULL()); 3285 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3286 } 3287 3288 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream))) 3289 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3290 commands); 3291 3292 error = sctp_eat_data(asoc, chunk, commands); 3293 switch (error) { 3294 case SCTP_IERROR_NO_ERROR: 3295 case SCTP_IERROR_HIGH_TSN: 3296 case SCTP_IERROR_DUP_TSN: 3297 case SCTP_IERROR_IGNORE_TSN: 3298 case SCTP_IERROR_BAD_STREAM: 3299 break; 3300 case SCTP_IERROR_NO_DATA: 3301 return SCTP_DISPOSITION_ABORT; 3302 case SCTP_IERROR_PROTO_VIOLATION: 3303 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3304 (u8 *)chunk->subh.data_hdr, 3305 sctp_datahdr_len(&asoc->stream)); 3306 default: 3307 BUG(); 3308 } 3309 3310 /* Go a head and force a SACK, since we are shutting down. */ 3311 3312 /* Implementor's Guide. 3313 * 3314 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3315 * respond to each received packet containing one or more DATA chunk(s) 3316 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3317 */ 3318 if (chunk->end_of_packet) { 3319 /* We must delay the chunk creation since the cumulative 3320 * TSN has not been updated yet. 3321 */ 3322 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3323 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3324 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3325 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3326 } 3327 3328 return SCTP_DISPOSITION_CONSUME; 3329 } 3330 3331 /* 3332 * Section: 6.2 Processing a Received SACK 3333 * D) Any time a SACK arrives, the endpoint performs the following: 3334 * 3335 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 3336 * then drop the SACK. Since Cumulative TSN Ack is monotonically 3337 * increasing, a SACK whose Cumulative TSN Ack is less than the 3338 * Cumulative TSN Ack Point indicates an out-of-order SACK. 3339 * 3340 * ii) Set rwnd equal to the newly received a_rwnd minus the number 3341 * of bytes still outstanding after processing the Cumulative TSN Ack 3342 * and the Gap Ack Blocks. 3343 * 3344 * iii) If the SACK is missing a TSN that was previously 3345 * acknowledged via a Gap Ack Block (e.g., the data receiver 3346 * reneged on the data), then mark the corresponding DATA chunk 3347 * as available for retransmit: Mark it as missing for fast 3348 * retransmit as described in Section 7.2.4 and if no retransmit 3349 * timer is running for the destination address to which the DATA 3350 * chunk was originally transmitted, then T3-rtx is started for 3351 * that destination address. 3352 * 3353 * Verification Tag: 8.5 Verification Tag [Normal verification] 3354 * 3355 * Inputs 3356 * (endpoint, asoc, chunk) 3357 * 3358 * Outputs 3359 * (asoc, reply_msg, msg_up, timers, counters) 3360 * 3361 * The return value is the disposition of the chunk. 3362 */ 3363 enum sctp_disposition sctp_sf_eat_sack_6_2(struct net *net, 3364 const struct sctp_endpoint *ep, 3365 const struct sctp_association *asoc, 3366 const union sctp_subtype type, 3367 void *arg, 3368 struct sctp_cmd_seq *commands) 3369 { 3370 struct sctp_chunk *chunk = arg; 3371 struct sctp_sackhdr *sackh; 3372 __u32 ctsn; 3373 3374 if (!sctp_vtag_verify(chunk, asoc)) 3375 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3376 3377 /* Make sure that the SACK chunk has a valid length. */ 3378 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_sack_chunk))) 3379 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3380 commands); 3381 3382 /* Pull the SACK chunk from the data buffer */ 3383 sackh = sctp_sm_pull_sack(chunk); 3384 /* Was this a bogus SACK? */ 3385 if (!sackh) 3386 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3387 chunk->subh.sack_hdr = sackh; 3388 ctsn = ntohl(sackh->cum_tsn_ack); 3389 3390 /* If Cumulative TSN Ack beyond the max tsn currently 3391 * send, terminating the association and respond to the 3392 * sender with an ABORT. 3393 */ 3394 if (TSN_lte(asoc->next_tsn, ctsn)) 3395 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 3396 3397 trace_sctp_probe(ep, asoc, chunk); 3398 3399 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 3400 * Ack Point, then drop the SACK. Since Cumulative TSN 3401 * Ack is monotonically increasing, a SACK whose 3402 * Cumulative TSN Ack is less than the Cumulative TSN Ack 3403 * Point indicates an out-of-order SACK. 3404 */ 3405 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 3406 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 3407 asoc->ctsn_ack_point); 3408 3409 return SCTP_DISPOSITION_DISCARD; 3410 } 3411 3412 /* Return this SACK for further processing. */ 3413 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk)); 3414 3415 /* Note: We do the rest of the work on the PROCESS_SACK 3416 * sideeffect. 3417 */ 3418 return SCTP_DISPOSITION_CONSUME; 3419 } 3420 3421 /* 3422 * Generate an ABORT in response to a packet. 3423 * 3424 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 3425 * 3426 * 8) The receiver should respond to the sender of the OOTB packet with 3427 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3428 * MUST fill in the Verification Tag field of the outbound packet 3429 * with the value found in the Verification Tag field of the OOTB 3430 * packet and set the T-bit in the Chunk Flags to indicate that the 3431 * Verification Tag is reflected. After sending this ABORT, the 3432 * receiver of the OOTB packet shall discard the OOTB packet and take 3433 * no further action. 3434 * 3435 * Verification Tag: 3436 * 3437 * The return value is the disposition of the chunk. 3438 */ 3439 static enum sctp_disposition sctp_sf_tabort_8_4_8( 3440 struct net *net, 3441 const struct sctp_endpoint *ep, 3442 const struct sctp_association *asoc, 3443 const union sctp_subtype type, 3444 void *arg, 3445 struct sctp_cmd_seq *commands) 3446 { 3447 struct sctp_packet *packet = NULL; 3448 struct sctp_chunk *chunk = arg; 3449 struct sctp_chunk *abort; 3450 3451 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3452 if (!packet) 3453 return SCTP_DISPOSITION_NOMEM; 3454 3455 /* Make an ABORT. The T bit will be set if the asoc 3456 * is NULL. 3457 */ 3458 abort = sctp_make_abort(asoc, chunk, 0); 3459 if (!abort) { 3460 sctp_ootb_pkt_free(packet); 3461 return SCTP_DISPOSITION_NOMEM; 3462 } 3463 3464 /* Reflect vtag if T-Bit is set */ 3465 if (sctp_test_T_bit(abort)) 3466 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3467 3468 /* Set the skb to the belonging sock for accounting. */ 3469 abort->skb->sk = ep->base.sk; 3470 3471 sctp_packet_append_chunk(packet, abort); 3472 3473 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(packet)); 3474 3475 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3476 3477 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3478 return SCTP_DISPOSITION_CONSUME; 3479 } 3480 3481 /* Handling of SCTP Packets Containing an INIT Chunk Matching an 3482 * Existing Associations when the UDP encap port is incorrect. 3483 * 3484 * From Section 4 at draft-tuexen-tsvwg-sctp-udp-encaps-cons-03. 3485 */ 3486 static enum sctp_disposition sctp_sf_new_encap_port( 3487 struct net *net, 3488 const struct sctp_endpoint *ep, 3489 const struct sctp_association *asoc, 3490 const union sctp_subtype type, 3491 void *arg, 3492 struct sctp_cmd_seq *commands) 3493 { 3494 struct sctp_packet *packet = NULL; 3495 struct sctp_chunk *chunk = arg; 3496 struct sctp_chunk *abort; 3497 3498 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3499 if (!packet) 3500 return SCTP_DISPOSITION_NOMEM; 3501 3502 abort = sctp_make_new_encap_port(asoc, chunk); 3503 if (!abort) { 3504 sctp_ootb_pkt_free(packet); 3505 return SCTP_DISPOSITION_NOMEM; 3506 } 3507 3508 abort->skb->sk = ep->base.sk; 3509 3510 sctp_packet_append_chunk(packet, abort); 3511 3512 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3513 SCTP_PACKET(packet)); 3514 3515 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3516 3517 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3518 return SCTP_DISPOSITION_CONSUME; 3519 } 3520 3521 /* 3522 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 3523 * event as ULP notification for each cause included in the chunk. 3524 * 3525 * API 5.3.1.3 - SCTP_REMOTE_ERROR 3526 * 3527 * The return value is the disposition of the chunk. 3528 */ 3529 enum sctp_disposition sctp_sf_operr_notify(struct net *net, 3530 const struct sctp_endpoint *ep, 3531 const struct sctp_association *asoc, 3532 const union sctp_subtype type, 3533 void *arg, 3534 struct sctp_cmd_seq *commands) 3535 { 3536 struct sctp_chunk *chunk = arg; 3537 struct sctp_errhdr *err; 3538 3539 if (!sctp_vtag_verify(chunk, asoc)) 3540 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3541 3542 /* Make sure that the ERROR chunk has a valid length. */ 3543 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk))) 3544 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3545 commands); 3546 sctp_walk_errors(err, chunk->chunk_hdr); 3547 if ((void *)err != (void *)chunk->chunk_end) 3548 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3549 (void *)err, commands); 3550 3551 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 3552 SCTP_CHUNK(chunk)); 3553 3554 return SCTP_DISPOSITION_CONSUME; 3555 } 3556 3557 /* 3558 * Process an inbound SHUTDOWN ACK. 3559 * 3560 * From Section 9.2: 3561 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3562 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 3563 * peer, and remove all record of the association. 3564 * 3565 * The return value is the disposition. 3566 */ 3567 enum sctp_disposition sctp_sf_do_9_2_final(struct net *net, 3568 const struct sctp_endpoint *ep, 3569 const struct sctp_association *asoc, 3570 const union sctp_subtype type, 3571 void *arg, 3572 struct sctp_cmd_seq *commands) 3573 { 3574 struct sctp_chunk *chunk = arg; 3575 struct sctp_chunk *reply; 3576 struct sctp_ulpevent *ev; 3577 3578 if (!sctp_vtag_verify(chunk, asoc)) 3579 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3580 3581 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3582 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3583 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3584 commands); 3585 /* 10.2 H) SHUTDOWN COMPLETE notification 3586 * 3587 * When SCTP completes the shutdown procedures (section 9.2) this 3588 * notification is passed to the upper layer. 3589 */ 3590 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3591 0, 0, 0, NULL, GFP_ATOMIC); 3592 if (!ev) 3593 goto nomem; 3594 3595 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3596 reply = sctp_make_shutdown_complete(asoc, chunk); 3597 if (!reply) 3598 goto nomem_chunk; 3599 3600 /* Do all the commands now (after allocation), so that we 3601 * have consistent state if memory allocation fails 3602 */ 3603 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3604 3605 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3606 * stop the T2-shutdown timer, 3607 */ 3608 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3609 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3610 3611 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3612 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3613 3614 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3615 SCTP_STATE(SCTP_STATE_CLOSED)); 3616 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 3617 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3618 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3619 3620 /* ...and remove all record of the association. */ 3621 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3622 return SCTP_DISPOSITION_DELETE_TCB; 3623 3624 nomem_chunk: 3625 sctp_ulpevent_free(ev); 3626 nomem: 3627 return SCTP_DISPOSITION_NOMEM; 3628 } 3629 3630 /* 3631 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3632 * 3633 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3634 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3635 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3636 * packet must fill in the Verification Tag field of the outbound 3637 * packet with the Verification Tag received in the SHUTDOWN ACK and 3638 * set the T-bit in the Chunk Flags to indicate that the Verification 3639 * Tag is reflected. 3640 * 3641 * 8) The receiver should respond to the sender of the OOTB packet with 3642 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3643 * MUST fill in the Verification Tag field of the outbound packet 3644 * with the value found in the Verification Tag field of the OOTB 3645 * packet and set the T-bit in the Chunk Flags to indicate that the 3646 * Verification Tag is reflected. After sending this ABORT, the 3647 * receiver of the OOTB packet shall discard the OOTB packet and take 3648 * no further action. 3649 */ 3650 enum sctp_disposition sctp_sf_ootb(struct net *net, 3651 const struct sctp_endpoint *ep, 3652 const struct sctp_association *asoc, 3653 const union sctp_subtype type, 3654 void *arg, struct sctp_cmd_seq *commands) 3655 { 3656 struct sctp_chunk *chunk = arg; 3657 struct sk_buff *skb = chunk->skb; 3658 struct sctp_chunkhdr *ch; 3659 struct sctp_errhdr *err; 3660 int ootb_cookie_ack = 0; 3661 int ootb_shut_ack = 0; 3662 __u8 *ch_end; 3663 3664 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3665 3666 ch = (struct sctp_chunkhdr *)chunk->chunk_hdr; 3667 do { 3668 /* Report violation if the chunk is less then minimal */ 3669 if (ntohs(ch->length) < sizeof(*ch)) 3670 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3671 commands); 3672 3673 /* Report violation if chunk len overflows */ 3674 ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length)); 3675 if (ch_end > skb_tail_pointer(skb)) 3676 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3677 commands); 3678 3679 /* Now that we know we at least have a chunk header, 3680 * do things that are type appropriate. 3681 */ 3682 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3683 ootb_shut_ack = 1; 3684 3685 /* RFC 2960, Section 3.3.7 3686 * Moreover, under any circumstances, an endpoint that 3687 * receives an ABORT MUST NOT respond to that ABORT by 3688 * sending an ABORT of its own. 3689 */ 3690 if (SCTP_CID_ABORT == ch->type) 3691 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3692 3693 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR 3694 * or a COOKIE ACK the SCTP Packet should be silently 3695 * discarded. 3696 */ 3697 3698 if (SCTP_CID_COOKIE_ACK == ch->type) 3699 ootb_cookie_ack = 1; 3700 3701 if (SCTP_CID_ERROR == ch->type) { 3702 sctp_walk_errors(err, ch) { 3703 if (SCTP_ERROR_STALE_COOKIE == err->cause) { 3704 ootb_cookie_ack = 1; 3705 break; 3706 } 3707 } 3708 } 3709 3710 ch = (struct sctp_chunkhdr *)ch_end; 3711 } while (ch_end < skb_tail_pointer(skb)); 3712 3713 if (ootb_shut_ack) 3714 return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands); 3715 else if (ootb_cookie_ack) 3716 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3717 else 3718 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 3719 } 3720 3721 /* 3722 * Handle an "Out of the blue" SHUTDOWN ACK. 3723 * 3724 * Section: 8.4 5, sctpimpguide 2.41. 3725 * 3726 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3727 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3728 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3729 * packet must fill in the Verification Tag field of the outbound 3730 * packet with the Verification Tag received in the SHUTDOWN ACK and 3731 * set the T-bit in the Chunk Flags to indicate that the Verification 3732 * Tag is reflected. 3733 * 3734 * Inputs 3735 * (endpoint, asoc, type, arg, commands) 3736 * 3737 * Outputs 3738 * (enum sctp_disposition) 3739 * 3740 * The return value is the disposition of the chunk. 3741 */ 3742 static enum sctp_disposition sctp_sf_shut_8_4_5( 3743 struct net *net, 3744 const struct sctp_endpoint *ep, 3745 const struct sctp_association *asoc, 3746 const union sctp_subtype type, 3747 void *arg, 3748 struct sctp_cmd_seq *commands) 3749 { 3750 struct sctp_packet *packet = NULL; 3751 struct sctp_chunk *chunk = arg; 3752 struct sctp_chunk *shut; 3753 3754 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3755 if (!packet) 3756 return SCTP_DISPOSITION_NOMEM; 3757 3758 /* Make an SHUTDOWN_COMPLETE. 3759 * The T bit will be set if the asoc is NULL. 3760 */ 3761 shut = sctp_make_shutdown_complete(asoc, chunk); 3762 if (!shut) { 3763 sctp_ootb_pkt_free(packet); 3764 return SCTP_DISPOSITION_NOMEM; 3765 } 3766 3767 /* Reflect vtag if T-Bit is set */ 3768 if (sctp_test_T_bit(shut)) 3769 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3770 3771 /* Set the skb to the belonging sock for accounting. */ 3772 shut->skb->sk = ep->base.sk; 3773 3774 sctp_packet_append_chunk(packet, shut); 3775 3776 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3777 SCTP_PACKET(packet)); 3778 3779 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3780 3781 /* If the chunk length is invalid, we don't want to process 3782 * the reset of the packet. 3783 */ 3784 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3785 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3786 3787 /* We need to discard the rest of the packet to prevent 3788 * potential boomming attacks from additional bundled chunks. 3789 * This is documented in SCTP Threats ID. 3790 */ 3791 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3792 } 3793 3794 /* 3795 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3796 * 3797 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3798 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3799 * procedures in section 8.4 SHOULD be followed, in other words it 3800 * should be treated as an Out Of The Blue packet. 3801 * [This means that we do NOT check the Verification Tag on these 3802 * chunks. --piggy ] 3803 * 3804 */ 3805 enum sctp_disposition sctp_sf_do_8_5_1_E_sa(struct net *net, 3806 const struct sctp_endpoint *ep, 3807 const struct sctp_association *asoc, 3808 const union sctp_subtype type, 3809 void *arg, 3810 struct sctp_cmd_seq *commands) 3811 { 3812 struct sctp_chunk *chunk = arg; 3813 3814 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3815 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3816 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3817 commands); 3818 3819 /* Although we do have an association in this case, it corresponds 3820 * to a restarted association. So the packet is treated as an OOTB 3821 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3822 * called with a NULL association. 3823 */ 3824 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3825 3826 return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands); 3827 } 3828 3829 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3830 enum sctp_disposition sctp_sf_do_asconf(struct net *net, 3831 const struct sctp_endpoint *ep, 3832 const struct sctp_association *asoc, 3833 const union sctp_subtype type, 3834 void *arg, 3835 struct sctp_cmd_seq *commands) 3836 { 3837 struct sctp_paramhdr *err_param = NULL; 3838 struct sctp_chunk *asconf_ack = NULL; 3839 struct sctp_chunk *chunk = arg; 3840 struct sctp_addiphdr *hdr; 3841 __u32 serial; 3842 3843 if (!sctp_vtag_verify(chunk, asoc)) { 3844 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3845 SCTP_NULL()); 3846 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3847 } 3848 3849 /* ADD-IP: Section 4.1.1 3850 * This chunk MUST be sent in an authenticated way by using 3851 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3852 * is received unauthenticated it MUST be silently discarded as 3853 * described in [I-D.ietf-tsvwg-sctp-auth]. 3854 */ 3855 if (!asoc->peer.asconf_capable || 3856 (!net->sctp.addip_noauth && !chunk->auth)) 3857 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, 3858 commands); 3859 3860 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3861 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_addip_chunk))) 3862 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3863 commands); 3864 3865 hdr = (struct sctp_addiphdr *)chunk->skb->data; 3866 serial = ntohl(hdr->serial); 3867 3868 /* Verify the ASCONF chunk before processing it. */ 3869 if (!sctp_verify_asconf(asoc, chunk, true, &err_param)) 3870 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3871 (void *)err_param, commands); 3872 3873 /* ADDIP 5.2 E1) Compare the value of the serial number to the value 3874 * the endpoint stored in a new association variable 3875 * 'Peer-Serial-Number'. 3876 */ 3877 if (serial == asoc->peer.addip_serial + 1) { 3878 /* If this is the first instance of ASCONF in the packet, 3879 * we can clean our old ASCONF-ACKs. 3880 */ 3881 if (!chunk->has_asconf) 3882 sctp_assoc_clean_asconf_ack_cache(asoc); 3883 3884 /* ADDIP 5.2 E4) When the Sequence Number matches the next one 3885 * expected, process the ASCONF as described below and after 3886 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to 3887 * the response packet and cache a copy of it (in the event it 3888 * later needs to be retransmitted). 3889 * 3890 * Essentially, do V1-V5. 3891 */ 3892 asconf_ack = sctp_process_asconf((struct sctp_association *) 3893 asoc, chunk); 3894 if (!asconf_ack) 3895 return SCTP_DISPOSITION_NOMEM; 3896 } else if (serial < asoc->peer.addip_serial + 1) { 3897 /* ADDIP 5.2 E2) 3898 * If the value found in the Sequence Number is less than the 3899 * ('Peer- Sequence-Number' + 1), simply skip to the next 3900 * ASCONF, and include in the outbound response packet 3901 * any previously cached ASCONF-ACK response that was 3902 * sent and saved that matches the Sequence Number of the 3903 * ASCONF. Note: It is possible that no cached ASCONF-ACK 3904 * Chunk exists. This will occur when an older ASCONF 3905 * arrives out of order. In such a case, the receiver 3906 * should skip the ASCONF Chunk and not include ASCONF-ACK 3907 * Chunk for that chunk. 3908 */ 3909 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial); 3910 if (!asconf_ack) 3911 return SCTP_DISPOSITION_DISCARD; 3912 3913 /* Reset the transport so that we select the correct one 3914 * this time around. This is to make sure that we don't 3915 * accidentally use a stale transport that's been removed. 3916 */ 3917 asconf_ack->transport = NULL; 3918 } else { 3919 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since 3920 * it must be either a stale packet or from an attacker. 3921 */ 3922 return SCTP_DISPOSITION_DISCARD; 3923 } 3924 3925 /* ADDIP 5.2 E6) The destination address of the SCTP packet 3926 * containing the ASCONF-ACK Chunks MUST be the source address of 3927 * the SCTP packet that held the ASCONF Chunks. 3928 * 3929 * To do this properly, we'll set the destination address of the chunk 3930 * and at the transmit time, will try look up the transport to use. 3931 * Since ASCONFs may be bundled, the correct transport may not be 3932 * created until we process the entire packet, thus this workaround. 3933 */ 3934 asconf_ack->dest = chunk->source; 3935 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3936 if (asoc->new_transport) { 3937 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, commands); 3938 ((struct sctp_association *)asoc)->new_transport = NULL; 3939 } 3940 3941 return SCTP_DISPOSITION_CONSUME; 3942 } 3943 3944 static enum sctp_disposition sctp_send_next_asconf( 3945 struct net *net, 3946 const struct sctp_endpoint *ep, 3947 struct sctp_association *asoc, 3948 const union sctp_subtype type, 3949 struct sctp_cmd_seq *commands) 3950 { 3951 struct sctp_chunk *asconf; 3952 struct list_head *entry; 3953 3954 if (list_empty(&asoc->addip_chunk_list)) 3955 return SCTP_DISPOSITION_CONSUME; 3956 3957 entry = asoc->addip_chunk_list.next; 3958 asconf = list_entry(entry, struct sctp_chunk, list); 3959 3960 list_del_init(entry); 3961 sctp_chunk_hold(asconf); 3962 asoc->addip_last_asconf = asconf; 3963 3964 return sctp_sf_do_prm_asconf(net, ep, asoc, type, asconf, commands); 3965 } 3966 3967 /* 3968 * ADDIP Section 4.3 General rules for address manipulation 3969 * When building TLV parameters for the ASCONF Chunk that will add or 3970 * delete IP addresses the D0 to D13 rules should be applied: 3971 */ 3972 enum sctp_disposition sctp_sf_do_asconf_ack(struct net *net, 3973 const struct sctp_endpoint *ep, 3974 const struct sctp_association *asoc, 3975 const union sctp_subtype type, 3976 void *arg, 3977 struct sctp_cmd_seq *commands) 3978 { 3979 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 3980 struct sctp_paramhdr *err_param = NULL; 3981 struct sctp_chunk *asconf_ack = arg; 3982 struct sctp_addiphdr *addip_hdr; 3983 __u32 sent_serial, rcvd_serial; 3984 struct sctp_chunk *abort; 3985 3986 if (!sctp_vtag_verify(asconf_ack, asoc)) { 3987 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3988 SCTP_NULL()); 3989 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3990 } 3991 3992 /* ADD-IP, Section 4.1.2: 3993 * This chunk MUST be sent in an authenticated way by using 3994 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3995 * is received unauthenticated it MUST be silently discarded as 3996 * described in [I-D.ietf-tsvwg-sctp-auth]. 3997 */ 3998 if (!asoc->peer.asconf_capable || 3999 (!net->sctp.addip_noauth && !asconf_ack->auth)) 4000 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, 4001 commands); 4002 4003 /* Make sure that the ADDIP chunk has a valid length. */ 4004 if (!sctp_chunk_length_valid(asconf_ack, 4005 sizeof(struct sctp_addip_chunk))) 4006 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4007 commands); 4008 4009 addip_hdr = (struct sctp_addiphdr *)asconf_ack->skb->data; 4010 rcvd_serial = ntohl(addip_hdr->serial); 4011 4012 /* Verify the ASCONF-ACK chunk before processing it. */ 4013 if (!sctp_verify_asconf(asoc, asconf_ack, false, &err_param)) 4014 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 4015 (void *)err_param, commands); 4016 4017 if (last_asconf) { 4018 addip_hdr = (struct sctp_addiphdr *)last_asconf->subh.addip_hdr; 4019 sent_serial = ntohl(addip_hdr->serial); 4020 } else { 4021 sent_serial = asoc->addip_serial - 1; 4022 } 4023 4024 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 4025 * equal to the next serial number to be used but no ASCONF chunk is 4026 * outstanding the endpoint MUST ABORT the association. Note that a 4027 * sequence number is greater than if it is no more than 2^^31-1 4028 * larger than the current sequence number (using serial arithmetic). 4029 */ 4030 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 4031 !(asoc->addip_last_asconf)) { 4032 abort = sctp_make_abort(asoc, asconf_ack, 4033 sizeof(struct sctp_errhdr)); 4034 if (abort) { 4035 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0); 4036 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4037 SCTP_CHUNK(abort)); 4038 } 4039 /* We are going to ABORT, so we might as well stop 4040 * processing the rest of the chunks in the packet. 4041 */ 4042 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4043 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 4044 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4045 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4046 SCTP_ERROR(ECONNABORTED)); 4047 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4048 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 4049 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4050 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4051 return SCTP_DISPOSITION_ABORT; 4052 } 4053 4054 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 4055 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4056 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 4057 4058 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 4059 asconf_ack)) 4060 return sctp_send_next_asconf(net, ep, 4061 (struct sctp_association *)asoc, 4062 type, commands); 4063 4064 abort = sctp_make_abort(asoc, asconf_ack, 4065 sizeof(struct sctp_errhdr)); 4066 if (abort) { 4067 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 4068 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4069 SCTP_CHUNK(abort)); 4070 } 4071 /* We are going to ABORT, so we might as well stop 4072 * processing the rest of the chunks in the packet. 4073 */ 4074 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4075 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4076 SCTP_ERROR(ECONNABORTED)); 4077 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4078 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 4079 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4080 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4081 return SCTP_DISPOSITION_ABORT; 4082 } 4083 4084 return SCTP_DISPOSITION_DISCARD; 4085 } 4086 4087 /* RE-CONFIG Section 5.2 Upon reception of an RECONF Chunk. */ 4088 enum sctp_disposition sctp_sf_do_reconf(struct net *net, 4089 const struct sctp_endpoint *ep, 4090 const struct sctp_association *asoc, 4091 const union sctp_subtype type, 4092 void *arg, 4093 struct sctp_cmd_seq *commands) 4094 { 4095 struct sctp_paramhdr *err_param = NULL; 4096 struct sctp_chunk *chunk = arg; 4097 struct sctp_reconf_chunk *hdr; 4098 union sctp_params param; 4099 4100 if (!sctp_vtag_verify(chunk, asoc)) { 4101 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4102 SCTP_NULL()); 4103 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4104 } 4105 4106 /* Make sure that the RECONF chunk has a valid length. */ 4107 if (!sctp_chunk_length_valid(chunk, sizeof(*hdr))) 4108 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4109 commands); 4110 4111 if (!sctp_verify_reconf(asoc, chunk, &err_param)) 4112 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 4113 (void *)err_param, commands); 4114 4115 hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr; 4116 sctp_walk_params(param, hdr, params) { 4117 struct sctp_chunk *reply = NULL; 4118 struct sctp_ulpevent *ev = NULL; 4119 4120 if (param.p->type == SCTP_PARAM_RESET_OUT_REQUEST) 4121 reply = sctp_process_strreset_outreq( 4122 (struct sctp_association *)asoc, param, &ev); 4123 else if (param.p->type == SCTP_PARAM_RESET_IN_REQUEST) 4124 reply = sctp_process_strreset_inreq( 4125 (struct sctp_association *)asoc, param, &ev); 4126 else if (param.p->type == SCTP_PARAM_RESET_TSN_REQUEST) 4127 reply = sctp_process_strreset_tsnreq( 4128 (struct sctp_association *)asoc, param, &ev); 4129 else if (param.p->type == SCTP_PARAM_RESET_ADD_OUT_STREAMS) 4130 reply = sctp_process_strreset_addstrm_out( 4131 (struct sctp_association *)asoc, param, &ev); 4132 else if (param.p->type == SCTP_PARAM_RESET_ADD_IN_STREAMS) 4133 reply = sctp_process_strreset_addstrm_in( 4134 (struct sctp_association *)asoc, param, &ev); 4135 else if (param.p->type == SCTP_PARAM_RESET_RESPONSE) 4136 reply = sctp_process_strreset_resp( 4137 (struct sctp_association *)asoc, param, &ev); 4138 4139 if (ev) 4140 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4141 SCTP_ULPEVENT(ev)); 4142 4143 if (reply) 4144 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4145 SCTP_CHUNK(reply)); 4146 } 4147 4148 return SCTP_DISPOSITION_CONSUME; 4149 } 4150 4151 /* 4152 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 4153 * 4154 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 4155 * its cumulative TSN point to the value carried in the FORWARD TSN 4156 * chunk, and then MUST further advance its cumulative TSN point locally 4157 * if possible. 4158 * After the above processing, the data receiver MUST stop reporting any 4159 * missing TSNs earlier than or equal to the new cumulative TSN point. 4160 * 4161 * Verification Tag: 8.5 Verification Tag [Normal verification] 4162 * 4163 * The return value is the disposition of the chunk. 4164 */ 4165 enum sctp_disposition sctp_sf_eat_fwd_tsn(struct net *net, 4166 const struct sctp_endpoint *ep, 4167 const struct sctp_association *asoc, 4168 const union sctp_subtype type, 4169 void *arg, 4170 struct sctp_cmd_seq *commands) 4171 { 4172 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 4173 struct sctp_chunk *chunk = arg; 4174 __u16 len; 4175 __u32 tsn; 4176 4177 if (!sctp_vtag_verify(chunk, asoc)) { 4178 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4179 SCTP_NULL()); 4180 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4181 } 4182 4183 if (!asoc->peer.prsctp_capable) 4184 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4185 4186 /* Make sure that the FORWARD_TSN chunk has valid length. */ 4187 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream))) 4188 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4189 commands); 4190 4191 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 4192 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 4193 len = ntohs(chunk->chunk_hdr->length); 4194 len -= sizeof(struct sctp_chunkhdr); 4195 skb_pull(chunk->skb, len); 4196 4197 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 4198 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 4199 4200 /* The TSN is too high--silently discard the chunk and count on it 4201 * getting retransmitted later. 4202 */ 4203 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 4204 goto discard_noforce; 4205 4206 if (!asoc->stream.si->validate_ftsn(chunk)) 4207 goto discard_noforce; 4208 4209 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 4210 if (len > sctp_ftsnhdr_len(&asoc->stream)) 4211 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 4212 SCTP_CHUNK(chunk)); 4213 4214 /* Count this as receiving DATA. */ 4215 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 4216 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4217 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 4218 } 4219 4220 /* FIXME: For now send a SACK, but DATA processing may 4221 * send another. 4222 */ 4223 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 4224 4225 return SCTP_DISPOSITION_CONSUME; 4226 4227 discard_noforce: 4228 return SCTP_DISPOSITION_DISCARD; 4229 } 4230 4231 enum sctp_disposition sctp_sf_eat_fwd_tsn_fast( 4232 struct net *net, 4233 const struct sctp_endpoint *ep, 4234 const struct sctp_association *asoc, 4235 const union sctp_subtype type, 4236 void *arg, 4237 struct sctp_cmd_seq *commands) 4238 { 4239 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 4240 struct sctp_chunk *chunk = arg; 4241 __u16 len; 4242 __u32 tsn; 4243 4244 if (!sctp_vtag_verify(chunk, asoc)) { 4245 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4246 SCTP_NULL()); 4247 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4248 } 4249 4250 if (!asoc->peer.prsctp_capable) 4251 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4252 4253 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 4254 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream))) 4255 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4256 commands); 4257 4258 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 4259 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 4260 len = ntohs(chunk->chunk_hdr->length); 4261 len -= sizeof(struct sctp_chunkhdr); 4262 skb_pull(chunk->skb, len); 4263 4264 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 4265 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 4266 4267 /* The TSN is too high--silently discard the chunk and count on it 4268 * getting retransmitted later. 4269 */ 4270 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 4271 goto gen_shutdown; 4272 4273 if (!asoc->stream.si->validate_ftsn(chunk)) 4274 goto gen_shutdown; 4275 4276 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 4277 if (len > sctp_ftsnhdr_len(&asoc->stream)) 4278 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 4279 SCTP_CHUNK(chunk)); 4280 4281 /* Go a head and force a SACK, since we are shutting down. */ 4282 gen_shutdown: 4283 /* Implementor's Guide. 4284 * 4285 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 4286 * respond to each received packet containing one or more DATA chunk(s) 4287 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 4288 */ 4289 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 4290 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 4291 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4292 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4293 4294 return SCTP_DISPOSITION_CONSUME; 4295 } 4296 4297 /* 4298 * SCTP-AUTH Section 6.3 Receiving authenticated chunks 4299 * 4300 * The receiver MUST use the HMAC algorithm indicated in the HMAC 4301 * Identifier field. If this algorithm was not specified by the 4302 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk 4303 * during association setup, the AUTH chunk and all chunks after it MUST 4304 * be discarded and an ERROR chunk SHOULD be sent with the error cause 4305 * defined in Section 4.1. 4306 * 4307 * If an endpoint with no shared key receives a Shared Key Identifier 4308 * other than 0, it MUST silently discard all authenticated chunks. If 4309 * the endpoint has at least one endpoint pair shared key for the peer, 4310 * it MUST use the key specified by the Shared Key Identifier if a 4311 * key has been configured for that Shared Key Identifier. If no 4312 * endpoint pair shared key has been configured for that Shared Key 4313 * Identifier, all authenticated chunks MUST be silently discarded. 4314 * 4315 * Verification Tag: 8.5 Verification Tag [Normal verification] 4316 * 4317 * The return value is the disposition of the chunk. 4318 */ 4319 static enum sctp_ierror sctp_sf_authenticate( 4320 const struct sctp_association *asoc, 4321 struct sctp_chunk *chunk) 4322 { 4323 struct sctp_shared_key *sh_key = NULL; 4324 struct sctp_authhdr *auth_hdr; 4325 __u8 *save_digest, *digest; 4326 struct sctp_hmac *hmac; 4327 unsigned int sig_len; 4328 __u16 key_id; 4329 4330 /* Pull in the auth header, so we can do some more verification */ 4331 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4332 chunk->subh.auth_hdr = auth_hdr; 4333 skb_pull(chunk->skb, sizeof(*auth_hdr)); 4334 4335 /* Make sure that we support the HMAC algorithm from the auth 4336 * chunk. 4337 */ 4338 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id)) 4339 return SCTP_IERROR_AUTH_BAD_HMAC; 4340 4341 /* Make sure that the provided shared key identifier has been 4342 * configured 4343 */ 4344 key_id = ntohs(auth_hdr->shkey_id); 4345 if (key_id != asoc->active_key_id) { 4346 sh_key = sctp_auth_get_shkey(asoc, key_id); 4347 if (!sh_key) 4348 return SCTP_IERROR_AUTH_BAD_KEYID; 4349 } 4350 4351 /* Make sure that the length of the signature matches what 4352 * we expect. 4353 */ 4354 sig_len = ntohs(chunk->chunk_hdr->length) - 4355 sizeof(struct sctp_auth_chunk); 4356 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id)); 4357 if (sig_len != hmac->hmac_len) 4358 return SCTP_IERROR_PROTO_VIOLATION; 4359 4360 /* Now that we've done validation checks, we can compute and 4361 * verify the hmac. The steps involved are: 4362 * 1. Save the digest from the chunk. 4363 * 2. Zero out the digest in the chunk. 4364 * 3. Compute the new digest 4365 * 4. Compare saved and new digests. 4366 */ 4367 digest = auth_hdr->hmac; 4368 skb_pull(chunk->skb, sig_len); 4369 4370 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC); 4371 if (!save_digest) 4372 goto nomem; 4373 4374 memset(digest, 0, sig_len); 4375 4376 sctp_auth_calculate_hmac(asoc, chunk->skb, 4377 (struct sctp_auth_chunk *)chunk->chunk_hdr, 4378 sh_key, GFP_ATOMIC); 4379 4380 /* Discard the packet if the digests do not match */ 4381 if (memcmp(save_digest, digest, sig_len)) { 4382 kfree(save_digest); 4383 return SCTP_IERROR_BAD_SIG; 4384 } 4385 4386 kfree(save_digest); 4387 chunk->auth = 1; 4388 4389 return SCTP_IERROR_NO_ERROR; 4390 nomem: 4391 return SCTP_IERROR_NOMEM; 4392 } 4393 4394 enum sctp_disposition sctp_sf_eat_auth(struct net *net, 4395 const struct sctp_endpoint *ep, 4396 const struct sctp_association *asoc, 4397 const union sctp_subtype type, 4398 void *arg, struct sctp_cmd_seq *commands) 4399 { 4400 struct sctp_chunk *chunk = arg; 4401 struct sctp_authhdr *auth_hdr; 4402 struct sctp_chunk *err_chunk; 4403 enum sctp_ierror error; 4404 4405 /* Make sure that the peer has AUTH capable */ 4406 if (!asoc->peer.auth_capable) 4407 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4408 4409 if (!sctp_vtag_verify(chunk, asoc)) { 4410 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4411 SCTP_NULL()); 4412 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4413 } 4414 4415 /* Make sure that the AUTH chunk has valid length. */ 4416 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk))) 4417 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4418 commands); 4419 4420 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4421 error = sctp_sf_authenticate(asoc, chunk); 4422 switch (error) { 4423 case SCTP_IERROR_AUTH_BAD_HMAC: 4424 /* Generate the ERROR chunk and discard the rest 4425 * of the packet 4426 */ 4427 err_chunk = sctp_make_op_error(asoc, chunk, 4428 SCTP_ERROR_UNSUP_HMAC, 4429 &auth_hdr->hmac_id, 4430 sizeof(__u16), 0); 4431 if (err_chunk) { 4432 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4433 SCTP_CHUNK(err_chunk)); 4434 } 4435 fallthrough; 4436 case SCTP_IERROR_AUTH_BAD_KEYID: 4437 case SCTP_IERROR_BAD_SIG: 4438 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4439 4440 case SCTP_IERROR_PROTO_VIOLATION: 4441 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4442 commands); 4443 4444 case SCTP_IERROR_NOMEM: 4445 return SCTP_DISPOSITION_NOMEM; 4446 4447 default: /* Prevent gcc warnings */ 4448 break; 4449 } 4450 4451 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) { 4452 struct sctp_ulpevent *ev; 4453 4454 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id), 4455 SCTP_AUTH_NEW_KEY, GFP_ATOMIC); 4456 4457 if (!ev) 4458 return -ENOMEM; 4459 4460 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4461 SCTP_ULPEVENT(ev)); 4462 } 4463 4464 return SCTP_DISPOSITION_CONSUME; 4465 } 4466 4467 /* 4468 * Process an unknown chunk. 4469 * 4470 * Section: 3.2. Also, 2.1 in the implementor's guide. 4471 * 4472 * Chunk Types are encoded such that the highest-order two bits specify 4473 * the action that must be taken if the processing endpoint does not 4474 * recognize the Chunk Type. 4475 * 4476 * 00 - Stop processing this SCTP packet and discard it, do not process 4477 * any further chunks within it. 4478 * 4479 * 01 - Stop processing this SCTP packet and discard it, do not process 4480 * any further chunks within it, and report the unrecognized 4481 * chunk in an 'Unrecognized Chunk Type'. 4482 * 4483 * 10 - Skip this chunk and continue processing. 4484 * 4485 * 11 - Skip this chunk and continue processing, but report in an ERROR 4486 * Chunk using the 'Unrecognized Chunk Type' cause of error. 4487 * 4488 * The return value is the disposition of the chunk. 4489 */ 4490 enum sctp_disposition sctp_sf_unk_chunk(struct net *net, 4491 const struct sctp_endpoint *ep, 4492 const struct sctp_association *asoc, 4493 const union sctp_subtype type, 4494 void *arg, 4495 struct sctp_cmd_seq *commands) 4496 { 4497 struct sctp_chunk *unk_chunk = arg; 4498 struct sctp_chunk *err_chunk; 4499 struct sctp_chunkhdr *hdr; 4500 4501 pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk); 4502 4503 if (!sctp_vtag_verify(unk_chunk, asoc)) 4504 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4505 4506 /* Make sure that the chunk has a valid length. 4507 * Since we don't know the chunk type, we use a general 4508 * chunkhdr structure to make a comparison. 4509 */ 4510 if (!sctp_chunk_length_valid(unk_chunk, sizeof(*hdr))) 4511 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4512 commands); 4513 4514 switch (type.chunk & SCTP_CID_ACTION_MASK) { 4515 case SCTP_CID_ACTION_DISCARD: 4516 /* Discard the packet. */ 4517 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4518 case SCTP_CID_ACTION_DISCARD_ERR: 4519 /* Generate an ERROR chunk as response. */ 4520 hdr = unk_chunk->chunk_hdr; 4521 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4522 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4523 SCTP_PAD4(ntohs(hdr->length)), 4524 0); 4525 if (err_chunk) { 4526 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4527 SCTP_CHUNK(err_chunk)); 4528 } 4529 4530 /* Discard the packet. */ 4531 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4532 return SCTP_DISPOSITION_CONSUME; 4533 case SCTP_CID_ACTION_SKIP: 4534 /* Skip the chunk. */ 4535 return SCTP_DISPOSITION_DISCARD; 4536 case SCTP_CID_ACTION_SKIP_ERR: 4537 /* Generate an ERROR chunk as response. */ 4538 hdr = unk_chunk->chunk_hdr; 4539 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4540 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4541 SCTP_PAD4(ntohs(hdr->length)), 4542 0); 4543 if (err_chunk) { 4544 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4545 SCTP_CHUNK(err_chunk)); 4546 } 4547 /* Skip the chunk. */ 4548 return SCTP_DISPOSITION_CONSUME; 4549 default: 4550 break; 4551 } 4552 4553 return SCTP_DISPOSITION_DISCARD; 4554 } 4555 4556 /* 4557 * Discard the chunk. 4558 * 4559 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 4560 * [Too numerous to mention...] 4561 * Verification Tag: No verification needed. 4562 * Inputs 4563 * (endpoint, asoc, chunk) 4564 * 4565 * Outputs 4566 * (asoc, reply_msg, msg_up, timers, counters) 4567 * 4568 * The return value is the disposition of the chunk. 4569 */ 4570 enum sctp_disposition sctp_sf_discard_chunk(struct net *net, 4571 const struct sctp_endpoint *ep, 4572 const struct sctp_association *asoc, 4573 const union sctp_subtype type, 4574 void *arg, 4575 struct sctp_cmd_seq *commands) 4576 { 4577 struct sctp_chunk *chunk = arg; 4578 4579 /* Make sure that the chunk has a valid length. 4580 * Since we don't know the chunk type, we use a general 4581 * chunkhdr structure to make a comparison. 4582 */ 4583 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 4584 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4585 commands); 4586 4587 pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk); 4588 4589 return SCTP_DISPOSITION_DISCARD; 4590 } 4591 4592 /* 4593 * Discard the whole packet. 4594 * 4595 * Section: 8.4 2) 4596 * 4597 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 4598 * silently discard the OOTB packet and take no further action. 4599 * 4600 * Verification Tag: No verification necessary 4601 * 4602 * Inputs 4603 * (endpoint, asoc, chunk) 4604 * 4605 * Outputs 4606 * (asoc, reply_msg, msg_up, timers, counters) 4607 * 4608 * The return value is the disposition of the chunk. 4609 */ 4610 enum sctp_disposition sctp_sf_pdiscard(struct net *net, 4611 const struct sctp_endpoint *ep, 4612 const struct sctp_association *asoc, 4613 const union sctp_subtype type, 4614 void *arg, struct sctp_cmd_seq *commands) 4615 { 4616 SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS); 4617 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4618 4619 return SCTP_DISPOSITION_CONSUME; 4620 } 4621 4622 4623 /* 4624 * The other end is violating protocol. 4625 * 4626 * Section: Not specified 4627 * Verification Tag: Not specified 4628 * Inputs 4629 * (endpoint, asoc, chunk) 4630 * 4631 * Outputs 4632 * (asoc, reply_msg, msg_up, timers, counters) 4633 * 4634 * We simply tag the chunk as a violation. The state machine will log 4635 * the violation and continue. 4636 */ 4637 enum sctp_disposition sctp_sf_violation(struct net *net, 4638 const struct sctp_endpoint *ep, 4639 const struct sctp_association *asoc, 4640 const union sctp_subtype type, 4641 void *arg, 4642 struct sctp_cmd_seq *commands) 4643 { 4644 struct sctp_chunk *chunk = arg; 4645 4646 /* Make sure that the chunk has a valid length. */ 4647 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 4648 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4649 commands); 4650 4651 return SCTP_DISPOSITION_VIOLATION; 4652 } 4653 4654 /* 4655 * Common function to handle a protocol violation. 4656 */ 4657 static enum sctp_disposition sctp_sf_abort_violation( 4658 struct net *net, 4659 const struct sctp_endpoint *ep, 4660 const struct sctp_association *asoc, 4661 void *arg, 4662 struct sctp_cmd_seq *commands, 4663 const __u8 *payload, 4664 const size_t paylen) 4665 { 4666 struct sctp_packet *packet = NULL; 4667 struct sctp_chunk *chunk = arg; 4668 struct sctp_chunk *abort = NULL; 4669 4670 /* SCTP-AUTH, Section 6.3: 4671 * It should be noted that if the receiver wants to tear 4672 * down an association in an authenticated way only, the 4673 * handling of malformed packets should not result in 4674 * tearing down the association. 4675 * 4676 * This means that if we only want to abort associations 4677 * in an authenticated way (i.e AUTH+ABORT), then we 4678 * can't destroy this association just because the packet 4679 * was malformed. 4680 */ 4681 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4682 goto discard; 4683 4684 /* Make the abort chunk. */ 4685 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen); 4686 if (!abort) 4687 goto nomem; 4688 4689 if (asoc) { 4690 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */ 4691 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK && 4692 !asoc->peer.i.init_tag) { 4693 struct sctp_initack_chunk *initack; 4694 4695 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr; 4696 if (!sctp_chunk_length_valid(chunk, sizeof(*initack))) 4697 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T; 4698 else { 4699 unsigned int inittag; 4700 4701 inittag = ntohl(initack->init_hdr.init_tag); 4702 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG, 4703 SCTP_U32(inittag)); 4704 } 4705 } 4706 4707 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4708 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4709 4710 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 4711 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4712 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4713 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4714 SCTP_ERROR(ECONNREFUSED)); 4715 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4716 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4717 } else { 4718 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4719 SCTP_ERROR(ECONNABORTED)); 4720 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4721 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4722 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4723 } 4724 } else { 4725 packet = sctp_ootb_pkt_new(net, asoc, chunk); 4726 4727 if (!packet) 4728 goto nomem_pkt; 4729 4730 if (sctp_test_T_bit(abort)) 4731 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 4732 4733 abort->skb->sk = ep->base.sk; 4734 4735 sctp_packet_append_chunk(packet, abort); 4736 4737 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 4738 SCTP_PACKET(packet)); 4739 4740 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4741 } 4742 4743 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4744 4745 discard: 4746 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4747 return SCTP_DISPOSITION_ABORT; 4748 4749 nomem_pkt: 4750 sctp_chunk_free(abort); 4751 nomem: 4752 return SCTP_DISPOSITION_NOMEM; 4753 } 4754 4755 /* 4756 * Handle a protocol violation when the chunk length is invalid. 4757 * "Invalid" length is identified as smaller than the minimal length a 4758 * given chunk can be. For example, a SACK chunk has invalid length 4759 * if its length is set to be smaller than the size of struct sctp_sack_chunk. 4760 * 4761 * We inform the other end by sending an ABORT with a Protocol Violation 4762 * error code. 4763 * 4764 * Section: Not specified 4765 * Verification Tag: Nothing to do 4766 * Inputs 4767 * (endpoint, asoc, chunk) 4768 * 4769 * Outputs 4770 * (reply_msg, msg_up, counters) 4771 * 4772 * Generate an ABORT chunk and terminate the association. 4773 */ 4774 static enum sctp_disposition sctp_sf_violation_chunklen( 4775 struct net *net, 4776 const struct sctp_endpoint *ep, 4777 const struct sctp_association *asoc, 4778 const union sctp_subtype type, 4779 void *arg, 4780 struct sctp_cmd_seq *commands) 4781 { 4782 static const char err_str[] = "The following chunk had invalid length:"; 4783 4784 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4785 sizeof(err_str)); 4786 } 4787 4788 /* 4789 * Handle a protocol violation when the parameter length is invalid. 4790 * If the length is smaller than the minimum length of a given parameter, 4791 * or accumulated length in multi parameters exceeds the end of the chunk, 4792 * the length is considered as invalid. 4793 */ 4794 static enum sctp_disposition sctp_sf_violation_paramlen( 4795 struct net *net, 4796 const struct sctp_endpoint *ep, 4797 const struct sctp_association *asoc, 4798 const union sctp_subtype type, 4799 void *arg, void *ext, 4800 struct sctp_cmd_seq *commands) 4801 { 4802 struct sctp_paramhdr *param = ext; 4803 struct sctp_chunk *abort = NULL; 4804 struct sctp_chunk *chunk = arg; 4805 4806 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4807 goto discard; 4808 4809 /* Make the abort chunk. */ 4810 abort = sctp_make_violation_paramlen(asoc, chunk, param); 4811 if (!abort) 4812 goto nomem; 4813 4814 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4815 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4816 4817 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4818 SCTP_ERROR(ECONNABORTED)); 4819 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4820 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4821 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4822 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4823 4824 discard: 4825 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4826 return SCTP_DISPOSITION_ABORT; 4827 nomem: 4828 return SCTP_DISPOSITION_NOMEM; 4829 } 4830 4831 /* Handle a protocol violation when the peer trying to advance the 4832 * cumulative tsn ack to a point beyond the max tsn currently sent. 4833 * 4834 * We inform the other end by sending an ABORT with a Protocol Violation 4835 * error code. 4836 */ 4837 static enum sctp_disposition sctp_sf_violation_ctsn( 4838 struct net *net, 4839 const struct sctp_endpoint *ep, 4840 const struct sctp_association *asoc, 4841 const union sctp_subtype type, 4842 void *arg, 4843 struct sctp_cmd_seq *commands) 4844 { 4845 static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:"; 4846 4847 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4848 sizeof(err_str)); 4849 } 4850 4851 /* Handle protocol violation of an invalid chunk bundling. For example, 4852 * when we have an association and we receive bundled INIT-ACK, or 4853 * SHUTDOWN-COMPLETE, our peer is clearly violating the "MUST NOT bundle" 4854 * statement from the specs. Additionally, there might be an attacker 4855 * on the path and we may not want to continue this communication. 4856 */ 4857 static enum sctp_disposition sctp_sf_violation_chunk( 4858 struct net *net, 4859 const struct sctp_endpoint *ep, 4860 const struct sctp_association *asoc, 4861 const union sctp_subtype type, 4862 void *arg, 4863 struct sctp_cmd_seq *commands) 4864 { 4865 static const char err_str[] = "The following chunk violates protocol:"; 4866 4867 if (!asoc) 4868 return sctp_sf_violation(net, ep, asoc, type, arg, commands); 4869 4870 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4871 sizeof(err_str)); 4872 } 4873 /*************************************************************************** 4874 * These are the state functions for handling primitive (Section 10) events. 4875 ***************************************************************************/ 4876 /* 4877 * sctp_sf_do_prm_asoc 4878 * 4879 * Section: 10.1 ULP-to-SCTP 4880 * B) Associate 4881 * 4882 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 4883 * outbound stream count) 4884 * -> association id [,destination transport addr list] [,outbound stream 4885 * count] 4886 * 4887 * This primitive allows the upper layer to initiate an association to a 4888 * specific peer endpoint. 4889 * 4890 * The peer endpoint shall be specified by one of the transport addresses 4891 * which defines the endpoint (see Section 1.4). If the local SCTP 4892 * instance has not been initialized, the ASSOCIATE is considered an 4893 * error. 4894 * [This is not relevant for the kernel implementation since we do all 4895 * initialization at boot time. It we hadn't initialized we wouldn't 4896 * get anywhere near this code.] 4897 * 4898 * An association id, which is a local handle to the SCTP association, 4899 * will be returned on successful establishment of the association. If 4900 * SCTP is not able to open an SCTP association with the peer endpoint, 4901 * an error is returned. 4902 * [In the kernel implementation, the struct sctp_association needs to 4903 * be created BEFORE causing this primitive to run.] 4904 * 4905 * Other association parameters may be returned, including the 4906 * complete destination transport addresses of the peer as well as the 4907 * outbound stream count of the local endpoint. One of the transport 4908 * address from the returned destination addresses will be selected by 4909 * the local endpoint as default primary path for sending SCTP packets 4910 * to this peer. The returned "destination transport addr list" can 4911 * be used by the ULP to change the default primary path or to force 4912 * sending a packet to a specific transport address. [All of this 4913 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 4914 * function.] 4915 * 4916 * Mandatory attributes: 4917 * 4918 * o local SCTP instance name - obtained from the INITIALIZE operation. 4919 * [This is the argument asoc.] 4920 * o destination transport addr - specified as one of the transport 4921 * addresses of the peer endpoint with which the association is to be 4922 * established. 4923 * [This is asoc->peer.active_path.] 4924 * o outbound stream count - the number of outbound streams the ULP 4925 * would like to open towards this peer endpoint. 4926 * [BUG: This is not currently implemented.] 4927 * Optional attributes: 4928 * 4929 * None. 4930 * 4931 * The return value is a disposition. 4932 */ 4933 enum sctp_disposition sctp_sf_do_prm_asoc(struct net *net, 4934 const struct sctp_endpoint *ep, 4935 const struct sctp_association *asoc, 4936 const union sctp_subtype type, 4937 void *arg, 4938 struct sctp_cmd_seq *commands) 4939 { 4940 struct sctp_association *my_asoc; 4941 struct sctp_chunk *repl; 4942 4943 /* The comment below says that we enter COOKIE-WAIT AFTER 4944 * sending the INIT, but that doesn't actually work in our 4945 * implementation... 4946 */ 4947 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4948 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 4949 4950 /* RFC 2960 5.1 Normal Establishment of an Association 4951 * 4952 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 4953 * must provide its Verification Tag (Tag_A) in the Initiate 4954 * Tag field. Tag_A SHOULD be a random number in the range of 4955 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 4956 */ 4957 4958 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 4959 if (!repl) 4960 goto nomem; 4961 4962 /* Choose transport for INIT. */ 4963 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 4964 SCTP_CHUNK(repl)); 4965 4966 /* Cast away the const modifier, as we want to just 4967 * rerun it through as a sideffect. 4968 */ 4969 my_asoc = (struct sctp_association *)asoc; 4970 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc)); 4971 4972 /* After sending the INIT, "A" starts the T1-init timer and 4973 * enters the COOKIE-WAIT state. 4974 */ 4975 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 4976 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4977 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 4978 return SCTP_DISPOSITION_CONSUME; 4979 4980 nomem: 4981 return SCTP_DISPOSITION_NOMEM; 4982 } 4983 4984 /* 4985 * Process the SEND primitive. 4986 * 4987 * Section: 10.1 ULP-to-SCTP 4988 * E) Send 4989 * 4990 * Format: SEND(association id, buffer address, byte count [,context] 4991 * [,stream id] [,life time] [,destination transport address] 4992 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 4993 * -> result 4994 * 4995 * This is the main method to send user data via SCTP. 4996 * 4997 * Mandatory attributes: 4998 * 4999 * o association id - local handle to the SCTP association 5000 * 5001 * o buffer address - the location where the user message to be 5002 * transmitted is stored; 5003 * 5004 * o byte count - The size of the user data in number of bytes; 5005 * 5006 * Optional attributes: 5007 * 5008 * o context - an optional 32 bit integer that will be carried in the 5009 * sending failure notification to the ULP if the transportation of 5010 * this User Message fails. 5011 * 5012 * o stream id - to indicate which stream to send the data on. If not 5013 * specified, stream 0 will be used. 5014 * 5015 * o life time - specifies the life time of the user data. The user data 5016 * will not be sent by SCTP after the life time expires. This 5017 * parameter can be used to avoid efforts to transmit stale 5018 * user messages. SCTP notifies the ULP if the data cannot be 5019 * initiated to transport (i.e. sent to the destination via SCTP's 5020 * send primitive) within the life time variable. However, the 5021 * user data will be transmitted if SCTP has attempted to transmit a 5022 * chunk before the life time expired. 5023 * 5024 * o destination transport address - specified as one of the destination 5025 * transport addresses of the peer endpoint to which this packet 5026 * should be sent. Whenever possible, SCTP should use this destination 5027 * transport address for sending the packets, instead of the current 5028 * primary path. 5029 * 5030 * o unorder flag - this flag, if present, indicates that the user 5031 * would like the data delivered in an unordered fashion to the peer 5032 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 5033 * message). 5034 * 5035 * o no-bundle flag - instructs SCTP not to bundle this user data with 5036 * other outbound DATA chunks. SCTP MAY still bundle even when 5037 * this flag is present, when faced with network congestion. 5038 * 5039 * o payload protocol-id - A 32 bit unsigned integer that is to be 5040 * passed to the peer indicating the type of payload protocol data 5041 * being transmitted. This value is passed as opaque data by SCTP. 5042 * 5043 * The return value is the disposition. 5044 */ 5045 enum sctp_disposition sctp_sf_do_prm_send(struct net *net, 5046 const struct sctp_endpoint *ep, 5047 const struct sctp_association *asoc, 5048 const union sctp_subtype type, 5049 void *arg, 5050 struct sctp_cmd_seq *commands) 5051 { 5052 struct sctp_datamsg *msg = arg; 5053 5054 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg)); 5055 return SCTP_DISPOSITION_CONSUME; 5056 } 5057 5058 /* 5059 * Process the SHUTDOWN primitive. 5060 * 5061 * Section: 10.1: 5062 * C) Shutdown 5063 * 5064 * Format: SHUTDOWN(association id) 5065 * -> result 5066 * 5067 * Gracefully closes an association. Any locally queued user data 5068 * will be delivered to the peer. The association will be terminated only 5069 * after the peer acknowledges all the SCTP packets sent. A success code 5070 * will be returned on successful termination of the association. If 5071 * attempting to terminate the association results in a failure, an error 5072 * code shall be returned. 5073 * 5074 * Mandatory attributes: 5075 * 5076 * o association id - local handle to the SCTP association 5077 * 5078 * Optional attributes: 5079 * 5080 * None. 5081 * 5082 * The return value is the disposition. 5083 */ 5084 enum sctp_disposition sctp_sf_do_9_2_prm_shutdown( 5085 struct net *net, 5086 const struct sctp_endpoint *ep, 5087 const struct sctp_association *asoc, 5088 const union sctp_subtype type, 5089 void *arg, 5090 struct sctp_cmd_seq *commands) 5091 { 5092 enum sctp_disposition disposition; 5093 5094 /* From 9.2 Shutdown of an Association 5095 * Upon receipt of the SHUTDOWN primitive from its upper 5096 * layer, the endpoint enters SHUTDOWN-PENDING state and 5097 * remains there until all outstanding data has been 5098 * acknowledged by its peer. The endpoint accepts no new data 5099 * from its upper layer, but retransmits data to the far end 5100 * if necessary to fill gaps. 5101 */ 5102 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5103 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 5104 5105 disposition = SCTP_DISPOSITION_CONSUME; 5106 if (sctp_outq_is_empty(&asoc->outqueue)) { 5107 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 5108 arg, commands); 5109 } 5110 5111 return disposition; 5112 } 5113 5114 /* 5115 * Process the ABORT primitive. 5116 * 5117 * Section: 10.1: 5118 * C) Abort 5119 * 5120 * Format: Abort(association id [, cause code]) 5121 * -> result 5122 * 5123 * Ungracefully closes an association. Any locally queued user data 5124 * will be discarded and an ABORT chunk is sent to the peer. A success code 5125 * will be returned on successful abortion of the association. If 5126 * attempting to abort the association results in a failure, an error 5127 * code shall be returned. 5128 * 5129 * Mandatory attributes: 5130 * 5131 * o association id - local handle to the SCTP association 5132 * 5133 * Optional attributes: 5134 * 5135 * o cause code - reason of the abort to be passed to the peer 5136 * 5137 * None. 5138 * 5139 * The return value is the disposition. 5140 */ 5141 enum sctp_disposition sctp_sf_do_9_1_prm_abort( 5142 struct net *net, 5143 const struct sctp_endpoint *ep, 5144 const struct sctp_association *asoc, 5145 const union sctp_subtype type, 5146 void *arg, 5147 struct sctp_cmd_seq *commands) 5148 { 5149 /* From 9.1 Abort of an Association 5150 * Upon receipt of the ABORT primitive from its upper 5151 * layer, the endpoint enters CLOSED state and 5152 * discard all outstanding data has been 5153 * acknowledged by its peer. The endpoint accepts no new data 5154 * from its upper layer, but retransmits data to the far end 5155 * if necessary to fill gaps. 5156 */ 5157 struct sctp_chunk *abort = arg; 5158 5159 if (abort) 5160 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 5161 5162 /* Even if we can't send the ABORT due to low memory delete the 5163 * TCB. This is a departure from our typical NOMEM handling. 5164 */ 5165 5166 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5167 SCTP_ERROR(ECONNABORTED)); 5168 /* Delete the established association. */ 5169 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5170 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 5171 5172 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5173 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5174 5175 return SCTP_DISPOSITION_ABORT; 5176 } 5177 5178 /* We tried an illegal operation on an association which is closed. */ 5179 enum sctp_disposition sctp_sf_error_closed(struct net *net, 5180 const struct sctp_endpoint *ep, 5181 const struct sctp_association *asoc, 5182 const union sctp_subtype type, 5183 void *arg, 5184 struct sctp_cmd_seq *commands) 5185 { 5186 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 5187 return SCTP_DISPOSITION_CONSUME; 5188 } 5189 5190 /* We tried an illegal operation on an association which is shutting 5191 * down. 5192 */ 5193 enum sctp_disposition sctp_sf_error_shutdown( 5194 struct net *net, 5195 const struct sctp_endpoint *ep, 5196 const struct sctp_association *asoc, 5197 const union sctp_subtype type, 5198 void *arg, 5199 struct sctp_cmd_seq *commands) 5200 { 5201 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, 5202 SCTP_ERROR(-ESHUTDOWN)); 5203 return SCTP_DISPOSITION_CONSUME; 5204 } 5205 5206 /* 5207 * sctp_cookie_wait_prm_shutdown 5208 * 5209 * Section: 4 Note: 2 5210 * Verification Tag: 5211 * Inputs 5212 * (endpoint, asoc) 5213 * 5214 * The RFC does not explicitly address this issue, but is the route through the 5215 * state table when someone issues a shutdown while in COOKIE_WAIT state. 5216 * 5217 * Outputs 5218 * (timers) 5219 */ 5220 enum sctp_disposition sctp_sf_cookie_wait_prm_shutdown( 5221 struct net *net, 5222 const struct sctp_endpoint *ep, 5223 const struct sctp_association *asoc, 5224 const union sctp_subtype type, 5225 void *arg, 5226 struct sctp_cmd_seq *commands) 5227 { 5228 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5229 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5230 5231 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5232 SCTP_STATE(SCTP_STATE_CLOSED)); 5233 5234 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 5235 5236 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 5237 5238 return SCTP_DISPOSITION_DELETE_TCB; 5239 } 5240 5241 /* 5242 * sctp_cookie_echoed_prm_shutdown 5243 * 5244 * Section: 4 Note: 2 5245 * Verification Tag: 5246 * Inputs 5247 * (endpoint, asoc) 5248 * 5249 * The RFC does not explicitly address this issue, but is the route through the 5250 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 5251 * 5252 * Outputs 5253 * (timers) 5254 */ 5255 enum sctp_disposition sctp_sf_cookie_echoed_prm_shutdown( 5256 struct net *net, 5257 const struct sctp_endpoint *ep, 5258 const struct sctp_association *asoc, 5259 const union sctp_subtype type, 5260 void *arg, 5261 struct sctp_cmd_seq *commands) 5262 { 5263 /* There is a single T1 timer, so we should be able to use 5264 * common function with the COOKIE-WAIT state. 5265 */ 5266 return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands); 5267 } 5268 5269 /* 5270 * sctp_sf_cookie_wait_prm_abort 5271 * 5272 * Section: 4 Note: 2 5273 * Verification Tag: 5274 * Inputs 5275 * (endpoint, asoc) 5276 * 5277 * The RFC does not explicitly address this issue, but is the route through the 5278 * state table when someone issues an abort while in COOKIE_WAIT state. 5279 * 5280 * Outputs 5281 * (timers) 5282 */ 5283 enum sctp_disposition sctp_sf_cookie_wait_prm_abort( 5284 struct net *net, 5285 const struct sctp_endpoint *ep, 5286 const struct sctp_association *asoc, 5287 const union sctp_subtype type, 5288 void *arg, 5289 struct sctp_cmd_seq *commands) 5290 { 5291 struct sctp_chunk *abort = arg; 5292 5293 /* Stop T1-init timer */ 5294 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5295 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5296 5297 if (abort) 5298 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 5299 5300 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5301 SCTP_STATE(SCTP_STATE_CLOSED)); 5302 5303 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5304 5305 /* Even if we can't send the ABORT due to low memory delete the 5306 * TCB. This is a departure from our typical NOMEM handling. 5307 */ 5308 5309 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5310 SCTP_ERROR(ECONNREFUSED)); 5311 /* Delete the established association. */ 5312 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5313 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 5314 5315 return SCTP_DISPOSITION_ABORT; 5316 } 5317 5318 /* 5319 * sctp_sf_cookie_echoed_prm_abort 5320 * 5321 * Section: 4 Note: 3 5322 * Verification Tag: 5323 * Inputs 5324 * (endpoint, asoc) 5325 * 5326 * The RFC does not explcitly address this issue, but is the route through the 5327 * state table when someone issues an abort while in COOKIE_ECHOED state. 5328 * 5329 * Outputs 5330 * (timers) 5331 */ 5332 enum sctp_disposition sctp_sf_cookie_echoed_prm_abort( 5333 struct net *net, 5334 const struct sctp_endpoint *ep, 5335 const struct sctp_association *asoc, 5336 const union sctp_subtype type, 5337 void *arg, 5338 struct sctp_cmd_seq *commands) 5339 { 5340 /* There is a single T1 timer, so we should be able to use 5341 * common function with the COOKIE-WAIT state. 5342 */ 5343 return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands); 5344 } 5345 5346 /* 5347 * sctp_sf_shutdown_pending_prm_abort 5348 * 5349 * Inputs 5350 * (endpoint, asoc) 5351 * 5352 * The RFC does not explicitly address this issue, but is the route through the 5353 * state table when someone issues an abort while in SHUTDOWN-PENDING state. 5354 * 5355 * Outputs 5356 * (timers) 5357 */ 5358 enum sctp_disposition sctp_sf_shutdown_pending_prm_abort( 5359 struct net *net, 5360 const struct sctp_endpoint *ep, 5361 const struct sctp_association *asoc, 5362 const union sctp_subtype type, 5363 void *arg, 5364 struct sctp_cmd_seq *commands) 5365 { 5366 /* Stop the T5-shutdown guard timer. */ 5367 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5368 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5369 5370 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5371 } 5372 5373 /* 5374 * sctp_sf_shutdown_sent_prm_abort 5375 * 5376 * Inputs 5377 * (endpoint, asoc) 5378 * 5379 * The RFC does not explicitly address this issue, but is the route through the 5380 * state table when someone issues an abort while in SHUTDOWN-SENT state. 5381 * 5382 * Outputs 5383 * (timers) 5384 */ 5385 enum sctp_disposition sctp_sf_shutdown_sent_prm_abort( 5386 struct net *net, 5387 const struct sctp_endpoint *ep, 5388 const struct sctp_association *asoc, 5389 const union sctp_subtype type, 5390 void *arg, 5391 struct sctp_cmd_seq *commands) 5392 { 5393 /* Stop the T2-shutdown timer. */ 5394 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5395 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5396 5397 /* Stop the T5-shutdown guard timer. */ 5398 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5399 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5400 5401 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5402 } 5403 5404 /* 5405 * sctp_sf_cookie_echoed_prm_abort 5406 * 5407 * Inputs 5408 * (endpoint, asoc) 5409 * 5410 * The RFC does not explcitly address this issue, but is the route through the 5411 * state table when someone issues an abort while in COOKIE_ECHOED state. 5412 * 5413 * Outputs 5414 * (timers) 5415 */ 5416 enum sctp_disposition sctp_sf_shutdown_ack_sent_prm_abort( 5417 struct net *net, 5418 const struct sctp_endpoint *ep, 5419 const struct sctp_association *asoc, 5420 const union sctp_subtype type, 5421 void *arg, 5422 struct sctp_cmd_seq *commands) 5423 { 5424 /* The same T2 timer, so we should be able to use 5425 * common function with the SHUTDOWN-SENT state. 5426 */ 5427 return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands); 5428 } 5429 5430 /* 5431 * Process the REQUESTHEARTBEAT primitive 5432 * 5433 * 10.1 ULP-to-SCTP 5434 * J) Request Heartbeat 5435 * 5436 * Format: REQUESTHEARTBEAT(association id, destination transport address) 5437 * 5438 * -> result 5439 * 5440 * Instructs the local endpoint to perform a HeartBeat on the specified 5441 * destination transport address of the given association. The returned 5442 * result should indicate whether the transmission of the HEARTBEAT 5443 * chunk to the destination address is successful. 5444 * 5445 * Mandatory attributes: 5446 * 5447 * o association id - local handle to the SCTP association 5448 * 5449 * o destination transport address - the transport address of the 5450 * association on which a heartbeat should be issued. 5451 */ 5452 enum sctp_disposition sctp_sf_do_prm_requestheartbeat( 5453 struct net *net, 5454 const struct sctp_endpoint *ep, 5455 const struct sctp_association *asoc, 5456 const union sctp_subtype type, 5457 void *arg, 5458 struct sctp_cmd_seq *commands) 5459 { 5460 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type, 5461 (struct sctp_transport *)arg, commands)) 5462 return SCTP_DISPOSITION_NOMEM; 5463 5464 /* 5465 * RFC 2960 (bis), section 8.3 5466 * 5467 * D) Request an on-demand HEARTBEAT on a specific destination 5468 * transport address of a given association. 5469 * 5470 * The endpoint should increment the respective error counter of 5471 * the destination transport address each time a HEARTBEAT is sent 5472 * to that address and not acknowledged within one RTO. 5473 * 5474 */ 5475 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 5476 SCTP_TRANSPORT(arg)); 5477 return SCTP_DISPOSITION_CONSUME; 5478 } 5479 5480 /* 5481 * ADDIP Section 4.1 ASCONF Chunk Procedures 5482 * When an endpoint has an ASCONF signaled change to be sent to the 5483 * remote endpoint it should do A1 to A9 5484 */ 5485 enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net, 5486 const struct sctp_endpoint *ep, 5487 const struct sctp_association *asoc, 5488 const union sctp_subtype type, 5489 void *arg, 5490 struct sctp_cmd_seq *commands) 5491 { 5492 struct sctp_chunk *chunk = arg; 5493 5494 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5495 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5496 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5497 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5498 return SCTP_DISPOSITION_CONSUME; 5499 } 5500 5501 /* RE-CONFIG Section 5.1 RECONF Chunk Procedures */ 5502 enum sctp_disposition sctp_sf_do_prm_reconf(struct net *net, 5503 const struct sctp_endpoint *ep, 5504 const struct sctp_association *asoc, 5505 const union sctp_subtype type, 5506 void *arg, 5507 struct sctp_cmd_seq *commands) 5508 { 5509 struct sctp_chunk *chunk = arg; 5510 5511 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5512 return SCTP_DISPOSITION_CONSUME; 5513 } 5514 5515 /* 5516 * Ignore the primitive event 5517 * 5518 * The return value is the disposition of the primitive. 5519 */ 5520 enum sctp_disposition sctp_sf_ignore_primitive( 5521 struct net *net, 5522 const struct sctp_endpoint *ep, 5523 const struct sctp_association *asoc, 5524 const union sctp_subtype type, 5525 void *arg, 5526 struct sctp_cmd_seq *commands) 5527 { 5528 pr_debug("%s: primitive type:%d is ignored\n", __func__, 5529 type.primitive); 5530 5531 return SCTP_DISPOSITION_DISCARD; 5532 } 5533 5534 /*************************************************************************** 5535 * These are the state functions for the OTHER events. 5536 ***************************************************************************/ 5537 5538 /* 5539 * When the SCTP stack has no more user data to send or retransmit, this 5540 * notification is given to the user. Also, at the time when a user app 5541 * subscribes to this event, if there is no data to be sent or 5542 * retransmit, the stack will immediately send up this notification. 5543 */ 5544 enum sctp_disposition sctp_sf_do_no_pending_tsn( 5545 struct net *net, 5546 const struct sctp_endpoint *ep, 5547 const struct sctp_association *asoc, 5548 const union sctp_subtype type, 5549 void *arg, 5550 struct sctp_cmd_seq *commands) 5551 { 5552 struct sctp_ulpevent *event; 5553 5554 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC); 5555 if (!event) 5556 return SCTP_DISPOSITION_NOMEM; 5557 5558 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event)); 5559 5560 return SCTP_DISPOSITION_CONSUME; 5561 } 5562 5563 /* 5564 * Start the shutdown negotiation. 5565 * 5566 * From Section 9.2: 5567 * Once all its outstanding data has been acknowledged, the endpoint 5568 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 5569 * TSN Ack field the last sequential TSN it has received from the peer. 5570 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 5571 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 5572 * with the updated last sequential TSN received from its peer. 5573 * 5574 * The return value is the disposition. 5575 */ 5576 enum sctp_disposition sctp_sf_do_9_2_start_shutdown( 5577 struct net *net, 5578 const struct sctp_endpoint *ep, 5579 const struct sctp_association *asoc, 5580 const union sctp_subtype type, 5581 void *arg, 5582 struct sctp_cmd_seq *commands) 5583 { 5584 struct sctp_chunk *reply; 5585 5586 /* Once all its outstanding data has been acknowledged, the 5587 * endpoint shall send a SHUTDOWN chunk to its peer including 5588 * in the Cumulative TSN Ack field the last sequential TSN it 5589 * has received from the peer. 5590 */ 5591 reply = sctp_make_shutdown(asoc, arg); 5592 if (!reply) 5593 goto nomem; 5594 5595 /* Set the transport for the SHUTDOWN chunk and the timeout for the 5596 * T2-shutdown timer. 5597 */ 5598 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5599 5600 /* It shall then start the T2-shutdown timer */ 5601 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5602 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5603 5604 /* RFC 4960 Section 9.2 5605 * The sender of the SHUTDOWN MAY also start an overall guard timer 5606 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5607 */ 5608 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5609 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5610 5611 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5612 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5613 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5614 5615 /* and enter the SHUTDOWN-SENT state. */ 5616 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5617 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 5618 5619 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5620 * 5621 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5622 * or SHUTDOWN-ACK. 5623 */ 5624 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5625 5626 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5627 5628 return SCTP_DISPOSITION_CONSUME; 5629 5630 nomem: 5631 return SCTP_DISPOSITION_NOMEM; 5632 } 5633 5634 /* 5635 * Generate a SHUTDOWN ACK now that everything is SACK'd. 5636 * 5637 * From Section 9.2: 5638 * 5639 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5640 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 5641 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 5642 * endpoint must re-send the SHUTDOWN ACK. 5643 * 5644 * The return value is the disposition. 5645 */ 5646 enum sctp_disposition sctp_sf_do_9_2_shutdown_ack( 5647 struct net *net, 5648 const struct sctp_endpoint *ep, 5649 const struct sctp_association *asoc, 5650 const union sctp_subtype type, 5651 void *arg, 5652 struct sctp_cmd_seq *commands) 5653 { 5654 struct sctp_chunk *chunk = arg; 5655 struct sctp_chunk *reply; 5656 5657 /* There are 2 ways of getting here: 5658 * 1) called in response to a SHUTDOWN chunk 5659 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 5660 * 5661 * For the case (2), the arg parameter is set to NULL. We need 5662 * to check that we have a chunk before accessing it's fields. 5663 */ 5664 if (chunk) { 5665 if (!sctp_vtag_verify(chunk, asoc)) 5666 return sctp_sf_pdiscard(net, ep, asoc, type, arg, 5667 commands); 5668 5669 /* Make sure that the SHUTDOWN chunk has a valid length. */ 5670 if (!sctp_chunk_length_valid( 5671 chunk, sizeof(struct sctp_shutdown_chunk))) 5672 return sctp_sf_violation_chunklen(net, ep, asoc, type, 5673 arg, commands); 5674 } 5675 5676 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5677 * shall send a SHUTDOWN ACK ... 5678 */ 5679 reply = sctp_make_shutdown_ack(asoc, chunk); 5680 if (!reply) 5681 goto nomem; 5682 5683 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 5684 * the T2-shutdown timer. 5685 */ 5686 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5687 5688 /* and start/restart a T2-shutdown timer of its own, */ 5689 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5690 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5691 5692 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5693 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5694 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5695 5696 /* Enter the SHUTDOWN-ACK-SENT state. */ 5697 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5698 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 5699 5700 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5701 * 5702 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5703 * or SHUTDOWN-ACK. 5704 */ 5705 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5706 5707 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5708 5709 return SCTP_DISPOSITION_CONSUME; 5710 5711 nomem: 5712 return SCTP_DISPOSITION_NOMEM; 5713 } 5714 5715 /* 5716 * Ignore the event defined as other 5717 * 5718 * The return value is the disposition of the event. 5719 */ 5720 enum sctp_disposition sctp_sf_ignore_other(struct net *net, 5721 const struct sctp_endpoint *ep, 5722 const struct sctp_association *asoc, 5723 const union sctp_subtype type, 5724 void *arg, 5725 struct sctp_cmd_seq *commands) 5726 { 5727 pr_debug("%s: the event other type:%d is ignored\n", 5728 __func__, type.other); 5729 5730 return SCTP_DISPOSITION_DISCARD; 5731 } 5732 5733 /************************************************************ 5734 * These are the state functions for handling timeout events. 5735 ************************************************************/ 5736 5737 /* 5738 * RTX Timeout 5739 * 5740 * Section: 6.3.3 Handle T3-rtx Expiration 5741 * 5742 * Whenever the retransmission timer T3-rtx expires for a destination 5743 * address, do the following: 5744 * [See below] 5745 * 5746 * The return value is the disposition of the chunk. 5747 */ 5748 enum sctp_disposition sctp_sf_do_6_3_3_rtx(struct net *net, 5749 const struct sctp_endpoint *ep, 5750 const struct sctp_association *asoc, 5751 const union sctp_subtype type, 5752 void *arg, 5753 struct sctp_cmd_seq *commands) 5754 { 5755 struct sctp_transport *transport = arg; 5756 5757 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS); 5758 5759 if (asoc->overall_error_count >= asoc->max_retrans) { 5760 if (asoc->peer.zero_window_announced && 5761 asoc->state == SCTP_STATE_SHUTDOWN_PENDING) { 5762 /* 5763 * We are here likely because the receiver had its rwnd 5764 * closed for a while and we have not been able to 5765 * transmit the locally queued data within the maximum 5766 * retransmission attempts limit. Start the T5 5767 * shutdown guard timer to give the receiver one last 5768 * chance and some additional time to recover before 5769 * aborting. 5770 */ 5771 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE, 5772 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5773 } else { 5774 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5775 SCTP_ERROR(ETIMEDOUT)); 5776 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5777 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5778 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5779 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5780 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5781 return SCTP_DISPOSITION_DELETE_TCB; 5782 } 5783 } 5784 5785 /* E1) For the destination address for which the timer 5786 * expires, adjust its ssthresh with rules defined in Section 5787 * 7.2.3 and set the cwnd <- MTU. 5788 */ 5789 5790 /* E2) For the destination address for which the timer 5791 * expires, set RTO <- RTO * 2 ("back off the timer"). The 5792 * maximum value discussed in rule C7 above (RTO.max) may be 5793 * used to provide an upper bound to this doubling operation. 5794 */ 5795 5796 /* E3) Determine how many of the earliest (i.e., lowest TSN) 5797 * outstanding DATA chunks for the address for which the 5798 * T3-rtx has expired will fit into a single packet, subject 5799 * to the MTU constraint for the path corresponding to the 5800 * destination transport address to which the retransmission 5801 * is being sent (this may be different from the address for 5802 * which the timer expires [see Section 6.4]). Call this 5803 * value K. Bundle and retransmit those K DATA chunks in a 5804 * single packet to the destination endpoint. 5805 * 5806 * Note: Any DATA chunks that were sent to the address for 5807 * which the T3-rtx timer expired but did not fit in one MTU 5808 * (rule E3 above), should be marked for retransmission and 5809 * sent as soon as cwnd allows (normally when a SACK arrives). 5810 */ 5811 5812 /* Do some failure management (Section 8.2). */ 5813 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5814 5815 /* NB: Rules E4 and F1 are implicit in R1. */ 5816 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 5817 5818 return SCTP_DISPOSITION_CONSUME; 5819 } 5820 5821 /* 5822 * Generate delayed SACK on timeout 5823 * 5824 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 5825 * 5826 * The guidelines on delayed acknowledgement algorithm specified in 5827 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 5828 * acknowledgement SHOULD be generated for at least every second packet 5829 * (not every second DATA chunk) received, and SHOULD be generated 5830 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 5831 * some situations it may be beneficial for an SCTP transmitter to be 5832 * more conservative than the algorithms detailed in this document 5833 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 5834 * the following algorithms allow. 5835 */ 5836 enum sctp_disposition sctp_sf_do_6_2_sack(struct net *net, 5837 const struct sctp_endpoint *ep, 5838 const struct sctp_association *asoc, 5839 const union sctp_subtype type, 5840 void *arg, 5841 struct sctp_cmd_seq *commands) 5842 { 5843 SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS); 5844 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 5845 return SCTP_DISPOSITION_CONSUME; 5846 } 5847 5848 /* 5849 * sctp_sf_t1_init_timer_expire 5850 * 5851 * Section: 4 Note: 2 5852 * Verification Tag: 5853 * Inputs 5854 * (endpoint, asoc) 5855 * 5856 * RFC 2960 Section 4 Notes 5857 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 5858 * and re-start the T1-init timer without changing state. This MUST 5859 * be repeated up to 'Max.Init.Retransmits' times. After that, the 5860 * endpoint MUST abort the initialization process and report the 5861 * error to SCTP user. 5862 * 5863 * Outputs 5864 * (timers, events) 5865 * 5866 */ 5867 enum sctp_disposition sctp_sf_t1_init_timer_expire( 5868 struct net *net, 5869 const struct sctp_endpoint *ep, 5870 const struct sctp_association *asoc, 5871 const union sctp_subtype type, 5872 void *arg, 5873 struct sctp_cmd_seq *commands) 5874 { 5875 int attempts = asoc->init_err_counter + 1; 5876 struct sctp_chunk *repl = NULL; 5877 struct sctp_bind_addr *bp; 5878 5879 pr_debug("%s: timer T1 expired (INIT)\n", __func__); 5880 5881 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS); 5882 5883 if (attempts <= asoc->max_init_attempts) { 5884 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 5885 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 5886 if (!repl) 5887 return SCTP_DISPOSITION_NOMEM; 5888 5889 /* Choose transport for INIT. */ 5890 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5891 SCTP_CHUNK(repl)); 5892 5893 /* Issue a sideeffect to do the needed accounting. */ 5894 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 5895 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5896 5897 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5898 } else { 5899 pr_debug("%s: giving up on INIT, attempts:%d " 5900 "max_init_attempts:%d\n", __func__, attempts, 5901 asoc->max_init_attempts); 5902 5903 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5904 SCTP_ERROR(ETIMEDOUT)); 5905 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5906 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5907 return SCTP_DISPOSITION_DELETE_TCB; 5908 } 5909 5910 return SCTP_DISPOSITION_CONSUME; 5911 } 5912 5913 /* 5914 * sctp_sf_t1_cookie_timer_expire 5915 * 5916 * Section: 4 Note: 2 5917 * Verification Tag: 5918 * Inputs 5919 * (endpoint, asoc) 5920 * 5921 * RFC 2960 Section 4 Notes 5922 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 5923 * COOKIE ECHO and re-start the T1-cookie timer without changing 5924 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 5925 * After that, the endpoint MUST abort the initialization process and 5926 * report the error to SCTP user. 5927 * 5928 * Outputs 5929 * (timers, events) 5930 * 5931 */ 5932 enum sctp_disposition sctp_sf_t1_cookie_timer_expire( 5933 struct net *net, 5934 const struct sctp_endpoint *ep, 5935 const struct sctp_association *asoc, 5936 const union sctp_subtype type, 5937 void *arg, 5938 struct sctp_cmd_seq *commands) 5939 { 5940 int attempts = asoc->init_err_counter + 1; 5941 struct sctp_chunk *repl = NULL; 5942 5943 pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__); 5944 5945 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS); 5946 5947 if (attempts <= asoc->max_init_attempts) { 5948 repl = sctp_make_cookie_echo(asoc, NULL); 5949 if (!repl) 5950 return SCTP_DISPOSITION_NOMEM; 5951 5952 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5953 SCTP_CHUNK(repl)); 5954 /* Issue a sideeffect to do the needed accounting. */ 5955 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 5956 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 5957 5958 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5959 } else { 5960 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5961 SCTP_ERROR(ETIMEDOUT)); 5962 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5963 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5964 return SCTP_DISPOSITION_DELETE_TCB; 5965 } 5966 5967 return SCTP_DISPOSITION_CONSUME; 5968 } 5969 5970 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 5971 * with the updated last sequential TSN received from its peer. 5972 * 5973 * An endpoint should limit the number of retransmission of the 5974 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 5975 * If this threshold is exceeded the endpoint should destroy the TCB and 5976 * MUST report the peer endpoint unreachable to the upper layer (and 5977 * thus the association enters the CLOSED state). The reception of any 5978 * packet from its peer (i.e. as the peer sends all of its queued DATA 5979 * chunks) should clear the endpoint's retransmission count and restart 5980 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 5981 * all of its queued DATA chunks that have not yet been sent. 5982 */ 5983 enum sctp_disposition sctp_sf_t2_timer_expire( 5984 struct net *net, 5985 const struct sctp_endpoint *ep, 5986 const struct sctp_association *asoc, 5987 const union sctp_subtype type, 5988 void *arg, 5989 struct sctp_cmd_seq *commands) 5990 { 5991 struct sctp_chunk *reply = NULL; 5992 5993 pr_debug("%s: timer T2 expired\n", __func__); 5994 5995 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS); 5996 5997 ((struct sctp_association *)asoc)->shutdown_retries++; 5998 5999 if (asoc->overall_error_count >= asoc->max_retrans) { 6000 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6001 SCTP_ERROR(ETIMEDOUT)); 6002 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 6003 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6004 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6005 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6006 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6007 return SCTP_DISPOSITION_DELETE_TCB; 6008 } 6009 6010 switch (asoc->state) { 6011 case SCTP_STATE_SHUTDOWN_SENT: 6012 reply = sctp_make_shutdown(asoc, NULL); 6013 break; 6014 6015 case SCTP_STATE_SHUTDOWN_ACK_SENT: 6016 reply = sctp_make_shutdown_ack(asoc, NULL); 6017 break; 6018 6019 default: 6020 BUG(); 6021 break; 6022 } 6023 6024 if (!reply) 6025 goto nomem; 6026 6027 /* Do some failure management (Section 8.2). 6028 * If we remove the transport an SHUTDOWN was last sent to, don't 6029 * do failure management. 6030 */ 6031 if (asoc->shutdown_last_sent_to) 6032 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 6033 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 6034 6035 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 6036 * the T2-shutdown timer. 6037 */ 6038 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 6039 6040 /* Restart the T2-shutdown timer. */ 6041 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 6042 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 6043 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 6044 return SCTP_DISPOSITION_CONSUME; 6045 6046 nomem: 6047 return SCTP_DISPOSITION_NOMEM; 6048 } 6049 6050 /* 6051 * ADDIP Section 4.1 ASCONF Chunk Procedures 6052 * If the T4 RTO timer expires the endpoint should do B1 to B5 6053 */ 6054 enum sctp_disposition sctp_sf_t4_timer_expire( 6055 struct net *net, 6056 const struct sctp_endpoint *ep, 6057 const struct sctp_association *asoc, 6058 const union sctp_subtype type, 6059 void *arg, 6060 struct sctp_cmd_seq *commands) 6061 { 6062 struct sctp_chunk *chunk = asoc->addip_last_asconf; 6063 struct sctp_transport *transport = chunk->transport; 6064 6065 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS); 6066 6067 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 6068 * detection on the appropriate destination address as defined in 6069 * RFC2960 [5] section 8.1 and 8.2. 6070 */ 6071 if (transport) 6072 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 6073 SCTP_TRANSPORT(transport)); 6074 6075 /* Reconfig T4 timer and transport. */ 6076 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 6077 6078 /* ADDIP 4.1 B2) Increment the association error counters and perform 6079 * endpoint failure detection on the association as defined in 6080 * RFC2960 [5] section 8.1 and 8.2. 6081 * association error counter is incremented in SCTP_CMD_STRIKE. 6082 */ 6083 if (asoc->overall_error_count >= asoc->max_retrans) { 6084 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 6085 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 6086 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6087 SCTP_ERROR(ETIMEDOUT)); 6088 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6089 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6090 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6091 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6092 return SCTP_DISPOSITION_ABORT; 6093 } 6094 6095 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 6096 * the ASCONF chunk was sent by doubling the RTO timer value. 6097 * This is done in SCTP_CMD_STRIKE. 6098 */ 6099 6100 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 6101 * choose an alternate destination address (please refer to RFC2960 6102 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 6103 * chunk, it MUST be the same (including its serial number) as the last 6104 * ASCONF sent. 6105 */ 6106 sctp_chunk_hold(asoc->addip_last_asconf); 6107 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6108 SCTP_CHUNK(asoc->addip_last_asconf)); 6109 6110 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 6111 * destination is selected, then the RTO used will be that of the new 6112 * destination address. 6113 */ 6114 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 6115 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 6116 6117 return SCTP_DISPOSITION_CONSUME; 6118 } 6119 6120 /* sctpimpguide-05 Section 2.12.2 6121 * The sender of the SHUTDOWN MAY also start an overall guard timer 6122 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 6123 * At the expiration of this timer the sender SHOULD abort the association 6124 * by sending an ABORT chunk. 6125 */ 6126 enum sctp_disposition sctp_sf_t5_timer_expire( 6127 struct net *net, 6128 const struct sctp_endpoint *ep, 6129 const struct sctp_association *asoc, 6130 const union sctp_subtype type, 6131 void *arg, 6132 struct sctp_cmd_seq *commands) 6133 { 6134 struct sctp_chunk *reply = NULL; 6135 6136 pr_debug("%s: timer T5 expired\n", __func__); 6137 6138 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS); 6139 6140 reply = sctp_make_abort(asoc, NULL, 0); 6141 if (!reply) 6142 goto nomem; 6143 6144 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 6145 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6146 SCTP_ERROR(ETIMEDOUT)); 6147 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6148 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6149 6150 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6151 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6152 6153 return SCTP_DISPOSITION_DELETE_TCB; 6154 nomem: 6155 return SCTP_DISPOSITION_NOMEM; 6156 } 6157 6158 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 6159 * the association is automatically closed by starting the shutdown process. 6160 * The work that needs to be done is same as when SHUTDOWN is initiated by 6161 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 6162 */ 6163 enum sctp_disposition sctp_sf_autoclose_timer_expire( 6164 struct net *net, 6165 const struct sctp_endpoint *ep, 6166 const struct sctp_association *asoc, 6167 const union sctp_subtype type, 6168 void *arg, 6169 struct sctp_cmd_seq *commands) 6170 { 6171 enum sctp_disposition disposition; 6172 6173 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS); 6174 6175 /* From 9.2 Shutdown of an Association 6176 * Upon receipt of the SHUTDOWN primitive from its upper 6177 * layer, the endpoint enters SHUTDOWN-PENDING state and 6178 * remains there until all outstanding data has been 6179 * acknowledged by its peer. The endpoint accepts no new data 6180 * from its upper layer, but retransmits data to the far end 6181 * if necessary to fill gaps. 6182 */ 6183 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 6184 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 6185 6186 disposition = SCTP_DISPOSITION_CONSUME; 6187 if (sctp_outq_is_empty(&asoc->outqueue)) { 6188 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 6189 NULL, commands); 6190 } 6191 6192 return disposition; 6193 } 6194 6195 /***************************************************************************** 6196 * These are sa state functions which could apply to all types of events. 6197 ****************************************************************************/ 6198 6199 /* 6200 * This table entry is not implemented. 6201 * 6202 * Inputs 6203 * (endpoint, asoc, chunk) 6204 * 6205 * The return value is the disposition of the chunk. 6206 */ 6207 enum sctp_disposition sctp_sf_not_impl(struct net *net, 6208 const struct sctp_endpoint *ep, 6209 const struct sctp_association *asoc, 6210 const union sctp_subtype type, 6211 void *arg, struct sctp_cmd_seq *commands) 6212 { 6213 return SCTP_DISPOSITION_NOT_IMPL; 6214 } 6215 6216 /* 6217 * This table entry represents a bug. 6218 * 6219 * Inputs 6220 * (endpoint, asoc, chunk) 6221 * 6222 * The return value is the disposition of the chunk. 6223 */ 6224 enum sctp_disposition sctp_sf_bug(struct net *net, 6225 const struct sctp_endpoint *ep, 6226 const struct sctp_association *asoc, 6227 const union sctp_subtype type, 6228 void *arg, struct sctp_cmd_seq *commands) 6229 { 6230 return SCTP_DISPOSITION_BUG; 6231 } 6232 6233 /* 6234 * This table entry represents the firing of a timer in the wrong state. 6235 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 6236 * when the association is in the wrong state. This event should 6237 * be ignored, so as to prevent any rearming of the timer. 6238 * 6239 * Inputs 6240 * (endpoint, asoc, chunk) 6241 * 6242 * The return value is the disposition of the chunk. 6243 */ 6244 enum sctp_disposition sctp_sf_timer_ignore(struct net *net, 6245 const struct sctp_endpoint *ep, 6246 const struct sctp_association *asoc, 6247 const union sctp_subtype type, 6248 void *arg, 6249 struct sctp_cmd_seq *commands) 6250 { 6251 pr_debug("%s: timer %d ignored\n", __func__, type.chunk); 6252 6253 return SCTP_DISPOSITION_CONSUME; 6254 } 6255 6256 /******************************************************************** 6257 * 2nd Level Abstractions 6258 ********************************************************************/ 6259 6260 /* Pull the SACK chunk based on the SACK header. */ 6261 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 6262 { 6263 struct sctp_sackhdr *sack; 6264 __u16 num_dup_tsns; 6265 unsigned int len; 6266 __u16 num_blocks; 6267 6268 /* Protect ourselves from reading too far into 6269 * the skb from a bogus sender. 6270 */ 6271 sack = (struct sctp_sackhdr *) chunk->skb->data; 6272 6273 num_blocks = ntohs(sack->num_gap_ack_blocks); 6274 num_dup_tsns = ntohs(sack->num_dup_tsns); 6275 len = sizeof(struct sctp_sackhdr); 6276 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 6277 if (len > chunk->skb->len) 6278 return NULL; 6279 6280 skb_pull(chunk->skb, len); 6281 6282 return sack; 6283 } 6284 6285 /* Create an ABORT packet to be sent as a response, with the specified 6286 * error causes. 6287 */ 6288 static struct sctp_packet *sctp_abort_pkt_new( 6289 struct net *net, 6290 const struct sctp_endpoint *ep, 6291 const struct sctp_association *asoc, 6292 struct sctp_chunk *chunk, 6293 const void *payload, size_t paylen) 6294 { 6295 struct sctp_packet *packet; 6296 struct sctp_chunk *abort; 6297 6298 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6299 6300 if (packet) { 6301 /* Make an ABORT. 6302 * The T bit will be set if the asoc is NULL. 6303 */ 6304 abort = sctp_make_abort(asoc, chunk, paylen); 6305 if (!abort) { 6306 sctp_ootb_pkt_free(packet); 6307 return NULL; 6308 } 6309 6310 /* Reflect vtag if T-Bit is set */ 6311 if (sctp_test_T_bit(abort)) 6312 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 6313 6314 /* Add specified error causes, i.e., payload, to the 6315 * end of the chunk. 6316 */ 6317 sctp_addto_chunk(abort, paylen, payload); 6318 6319 /* Set the skb to the belonging sock for accounting. */ 6320 abort->skb->sk = ep->base.sk; 6321 6322 sctp_packet_append_chunk(packet, abort); 6323 6324 } 6325 6326 return packet; 6327 } 6328 6329 /* Allocate a packet for responding in the OOTB conditions. */ 6330 static struct sctp_packet *sctp_ootb_pkt_new( 6331 struct net *net, 6332 const struct sctp_association *asoc, 6333 const struct sctp_chunk *chunk) 6334 { 6335 struct sctp_transport *transport; 6336 struct sctp_packet *packet; 6337 __u16 sport, dport; 6338 __u32 vtag; 6339 6340 /* Get the source and destination port from the inbound packet. */ 6341 sport = ntohs(chunk->sctp_hdr->dest); 6342 dport = ntohs(chunk->sctp_hdr->source); 6343 6344 /* The V-tag is going to be the same as the inbound packet if no 6345 * association exists, otherwise, use the peer's vtag. 6346 */ 6347 if (asoc) { 6348 /* Special case the INIT-ACK as there is no peer's vtag 6349 * yet. 6350 */ 6351 switch (chunk->chunk_hdr->type) { 6352 case SCTP_CID_INIT_ACK: 6353 { 6354 struct sctp_initack_chunk *initack; 6355 6356 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr; 6357 vtag = ntohl(initack->init_hdr.init_tag); 6358 break; 6359 } 6360 default: 6361 vtag = asoc->peer.i.init_tag; 6362 break; 6363 } 6364 } else { 6365 /* Special case the INIT and stale COOKIE_ECHO as there is no 6366 * vtag yet. 6367 */ 6368 switch (chunk->chunk_hdr->type) { 6369 case SCTP_CID_INIT: 6370 { 6371 struct sctp_init_chunk *init; 6372 6373 init = (struct sctp_init_chunk *)chunk->chunk_hdr; 6374 vtag = ntohl(init->init_hdr.init_tag); 6375 break; 6376 } 6377 default: 6378 vtag = ntohl(chunk->sctp_hdr->vtag); 6379 break; 6380 } 6381 } 6382 6383 /* Make a transport for the bucket, Eliza... */ 6384 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC); 6385 if (!transport) 6386 goto nomem; 6387 6388 transport->encap_port = SCTP_INPUT_CB(chunk->skb)->encap_port; 6389 6390 /* Cache a route for the transport with the chunk's destination as 6391 * the source address. 6392 */ 6393 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 6394 sctp_sk(net->sctp.ctl_sock)); 6395 6396 packet = &transport->packet; 6397 sctp_packet_init(packet, transport, sport, dport); 6398 sctp_packet_config(packet, vtag, 0); 6399 6400 return packet; 6401 6402 nomem: 6403 return NULL; 6404 } 6405 6406 /* Free the packet allocated earlier for responding in the OOTB condition. */ 6407 void sctp_ootb_pkt_free(struct sctp_packet *packet) 6408 { 6409 sctp_transport_free(packet->transport); 6410 } 6411 6412 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 6413 static void sctp_send_stale_cookie_err(struct net *net, 6414 const struct sctp_endpoint *ep, 6415 const struct sctp_association *asoc, 6416 const struct sctp_chunk *chunk, 6417 struct sctp_cmd_seq *commands, 6418 struct sctp_chunk *err_chunk) 6419 { 6420 struct sctp_packet *packet; 6421 6422 if (err_chunk) { 6423 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6424 if (packet) { 6425 struct sctp_signed_cookie *cookie; 6426 6427 /* Override the OOTB vtag from the cookie. */ 6428 cookie = chunk->subh.cookie_hdr; 6429 packet->vtag = cookie->c.peer_vtag; 6430 6431 /* Set the skb to the belonging sock for accounting. */ 6432 err_chunk->skb->sk = ep->base.sk; 6433 sctp_packet_append_chunk(packet, err_chunk); 6434 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 6435 SCTP_PACKET(packet)); 6436 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 6437 } else 6438 sctp_chunk_free (err_chunk); 6439 } 6440 } 6441 6442 6443 /* Process a data chunk */ 6444 static int sctp_eat_data(const struct sctp_association *asoc, 6445 struct sctp_chunk *chunk, 6446 struct sctp_cmd_seq *commands) 6447 { 6448 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; 6449 struct sock *sk = asoc->base.sk; 6450 struct net *net = sock_net(sk); 6451 struct sctp_datahdr *data_hdr; 6452 struct sctp_chunk *err; 6453 enum sctp_verb deliver; 6454 size_t datalen; 6455 __u32 tsn; 6456 int tmp; 6457 6458 data_hdr = (struct sctp_datahdr *)chunk->skb->data; 6459 chunk->subh.data_hdr = data_hdr; 6460 skb_pull(chunk->skb, sctp_datahdr_len(&asoc->stream)); 6461 6462 tsn = ntohl(data_hdr->tsn); 6463 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 6464 6465 /* ASSERT: Now skb->data is really the user data. */ 6466 6467 /* Process ECN based congestion. 6468 * 6469 * Since the chunk structure is reused for all chunks within 6470 * a packet, we use ecn_ce_done to track if we've already 6471 * done CE processing for this packet. 6472 * 6473 * We need to do ECN processing even if we plan to discard the 6474 * chunk later. 6475 */ 6476 6477 if (asoc->peer.ecn_capable && !chunk->ecn_ce_done) { 6478 struct sctp_af *af = SCTP_INPUT_CB(chunk->skb)->af; 6479 chunk->ecn_ce_done = 1; 6480 6481 if (af->is_ce(sctp_gso_headskb(chunk->skb))) { 6482 /* Do real work as side effect. */ 6483 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 6484 SCTP_U32(tsn)); 6485 } 6486 } 6487 6488 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 6489 if (tmp < 0) { 6490 /* The TSN is too high--silently discard the chunk and 6491 * count on it getting retransmitted later. 6492 */ 6493 if (chunk->asoc) 6494 chunk->asoc->stats.outofseqtsns++; 6495 return SCTP_IERROR_HIGH_TSN; 6496 } else if (tmp > 0) { 6497 /* This is a duplicate. Record it. */ 6498 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 6499 return SCTP_IERROR_DUP_TSN; 6500 } 6501 6502 /* This is a new TSN. */ 6503 6504 /* Discard if there is no room in the receive window. 6505 * Actually, allow a little bit of overflow (up to a MTU). 6506 */ 6507 datalen = ntohs(chunk->chunk_hdr->length); 6508 datalen -= sctp_datachk_len(&asoc->stream); 6509 6510 deliver = SCTP_CMD_CHUNK_ULP; 6511 6512 /* Think about partial delivery. */ 6513 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 6514 6515 /* Even if we don't accept this chunk there is 6516 * memory pressure. 6517 */ 6518 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 6519 } 6520 6521 /* Spill over rwnd a little bit. Note: While allowed, this spill over 6522 * seems a bit troublesome in that frag_point varies based on 6523 * PMTU. In cases, such as loopback, this might be a rather 6524 * large spill over. 6525 */ 6526 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over || 6527 (datalen > asoc->rwnd + asoc->frag_point))) { 6528 6529 /* If this is the next TSN, consider reneging to make 6530 * room. Note: Playing nice with a confused sender. A 6531 * malicious sender can still eat up all our buffer 6532 * space and in the future we may want to detect and 6533 * do more drastic reneging. 6534 */ 6535 if (sctp_tsnmap_has_gap(map) && 6536 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6537 pr_debug("%s: reneging for tsn:%u\n", __func__, tsn); 6538 deliver = SCTP_CMD_RENEGE; 6539 } else { 6540 pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n", 6541 __func__, tsn, datalen, asoc->rwnd); 6542 6543 return SCTP_IERROR_IGNORE_TSN; 6544 } 6545 } 6546 6547 /* 6548 * Also try to renege to limit our memory usage in the event that 6549 * we are under memory pressure 6550 * If we can't renege, don't worry about it, the sk_rmem_schedule 6551 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our 6552 * memory usage too much 6553 */ 6554 if (sk_under_memory_pressure(sk)) { 6555 if (sctp_tsnmap_has_gap(map) && 6556 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6557 pr_debug("%s: under pressure, reneging for tsn:%u\n", 6558 __func__, tsn); 6559 deliver = SCTP_CMD_RENEGE; 6560 } else { 6561 sk_mem_reclaim(sk); 6562 } 6563 } 6564 6565 /* 6566 * Section 3.3.10.9 No User Data (9) 6567 * 6568 * Cause of error 6569 * --------------- 6570 * No User Data: This error cause is returned to the originator of a 6571 * DATA chunk if a received DATA chunk has no user data. 6572 */ 6573 if (unlikely(0 == datalen)) { 6574 err = sctp_make_abort_no_data(asoc, chunk, tsn); 6575 if (err) { 6576 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6577 SCTP_CHUNK(err)); 6578 } 6579 /* We are going to ABORT, so we might as well stop 6580 * processing the rest of the chunks in the packet. 6581 */ 6582 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 6583 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6584 SCTP_ERROR(ECONNABORTED)); 6585 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6586 SCTP_PERR(SCTP_ERROR_NO_DATA)); 6587 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6588 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6589 return SCTP_IERROR_NO_DATA; 6590 } 6591 6592 chunk->data_accepted = 1; 6593 6594 /* Note: Some chunks may get overcounted (if we drop) or overcounted 6595 * if we renege and the chunk arrives again. 6596 */ 6597 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) { 6598 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS); 6599 if (chunk->asoc) 6600 chunk->asoc->stats.iuodchunks++; 6601 } else { 6602 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS); 6603 if (chunk->asoc) 6604 chunk->asoc->stats.iodchunks++; 6605 } 6606 6607 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 6608 * 6609 * If an endpoint receive a DATA chunk with an invalid stream 6610 * identifier, it shall acknowledge the reception of the DATA chunk 6611 * following the normal procedure, immediately send an ERROR chunk 6612 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 6613 * and discard the DATA chunk. 6614 */ 6615 if (ntohs(data_hdr->stream) >= asoc->stream.incnt) { 6616 /* Mark tsn as received even though we drop it */ 6617 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 6618 6619 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 6620 &data_hdr->stream, 6621 sizeof(data_hdr->stream), 6622 sizeof(u16)); 6623 if (err) 6624 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6625 SCTP_CHUNK(err)); 6626 return SCTP_IERROR_BAD_STREAM; 6627 } 6628 6629 /* Check to see if the SSN is possible for this TSN. 6630 * The biggest gap we can record is 4K wide. Since SSNs wrap 6631 * at an unsigned short, there is no way that an SSN can 6632 * wrap and for a valid TSN. We can simply check if the current 6633 * SSN is smaller then the next expected one. If it is, it wrapped 6634 * and is invalid. 6635 */ 6636 if (!asoc->stream.si->validate_data(chunk)) 6637 return SCTP_IERROR_PROTO_VIOLATION; 6638 6639 /* Send the data up to the user. Note: Schedule the 6640 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 6641 * chunk needs the updated rwnd. 6642 */ 6643 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 6644 6645 return SCTP_IERROR_NO_ERROR; 6646 } 6647