1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* SCTP kernel implementation 3 * (C) Copyright IBM Corp. 2001, 2004 4 * Copyright (c) 1999-2000 Cisco, Inc. 5 * Copyright (c) 1999-2001 Motorola, Inc. 6 * Copyright (c) 2001-2002 Intel Corp. 7 * Copyright (c) 2002 Nokia Corp. 8 * 9 * This is part of the SCTP Linux Kernel Implementation. 10 * 11 * These are the state functions for the state machine. 12 * 13 * Please send any bug reports or fixes you make to the 14 * email address(es): 15 * lksctp developers <linux-sctp@vger.kernel.org> 16 * 17 * Written or modified by: 18 * La Monte H.P. Yarroll <piggy@acm.org> 19 * Karl Knutson <karl@athena.chicago.il.us> 20 * Mathew Kotowsky <kotowsky@sctp.org> 21 * Sridhar Samudrala <samudrala@us.ibm.com> 22 * Jon Grimm <jgrimm@us.ibm.com> 23 * Hui Huang <hui.huang@nokia.com> 24 * Dajiang Zhang <dajiang.zhang@nokia.com> 25 * Daisy Chang <daisyc@us.ibm.com> 26 * Ardelle Fan <ardelle.fan@intel.com> 27 * Ryan Layer <rmlayer@us.ibm.com> 28 * Kevin Gao <kevin.gao@intel.com> 29 */ 30 31 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 32 33 #include <crypto/utils.h> 34 #include <linux/types.h> 35 #include <linux/kernel.h> 36 #include <linux/ip.h> 37 #include <linux/ipv6.h> 38 #include <linux/net.h> 39 #include <linux/inet.h> 40 #include <linux/slab.h> 41 #include <net/sock.h> 42 #include <net/proto_memory.h> 43 #include <net/inet_ecn.h> 44 #include <linux/skbuff.h> 45 #include <net/sctp/sctp.h> 46 #include <net/sctp/sm.h> 47 #include <net/sctp/structs.h> 48 49 #define CREATE_TRACE_POINTS 50 #include <trace/events/sctp.h> 51 52 static struct sctp_packet *sctp_abort_pkt_new( 53 struct net *net, 54 const struct sctp_endpoint *ep, 55 const struct sctp_association *asoc, 56 struct sctp_chunk *chunk, 57 const void *payload, size_t paylen); 58 static int sctp_eat_data(const struct sctp_association *asoc, 59 struct sctp_chunk *chunk, 60 struct sctp_cmd_seq *commands); 61 static struct sctp_packet *sctp_ootb_pkt_new( 62 struct net *net, 63 const struct sctp_association *asoc, 64 const struct sctp_chunk *chunk); 65 static void sctp_send_stale_cookie_err(struct net *net, 66 const struct sctp_endpoint *ep, 67 const struct sctp_association *asoc, 68 const struct sctp_chunk *chunk, 69 struct sctp_cmd_seq *commands, 70 struct sctp_chunk *err_chunk); 71 static enum sctp_disposition sctp_sf_do_5_2_6_stale( 72 struct net *net, 73 const struct sctp_endpoint *ep, 74 const struct sctp_association *asoc, 75 const union sctp_subtype type, 76 void *arg, 77 struct sctp_cmd_seq *commands); 78 static enum sctp_disposition sctp_sf_shut_8_4_5( 79 struct net *net, 80 const struct sctp_endpoint *ep, 81 const struct sctp_association *asoc, 82 const union sctp_subtype type, 83 void *arg, 84 struct sctp_cmd_seq *commands); 85 static enum sctp_disposition sctp_sf_tabort_8_4_8( 86 struct net *net, 87 const struct sctp_endpoint *ep, 88 const struct sctp_association *asoc, 89 const union sctp_subtype type, 90 void *arg, 91 struct sctp_cmd_seq *commands); 92 static enum sctp_disposition sctp_sf_new_encap_port( 93 struct net *net, 94 const struct sctp_endpoint *ep, 95 const struct sctp_association *asoc, 96 const union sctp_subtype type, 97 void *arg, 98 struct sctp_cmd_seq *commands); 99 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk); 100 101 static enum sctp_disposition sctp_stop_t1_and_abort( 102 struct net *net, 103 struct sctp_cmd_seq *commands, 104 __be16 error, int sk_err, 105 const struct sctp_association *asoc, 106 struct sctp_transport *transport); 107 108 static enum sctp_disposition sctp_sf_abort_violation( 109 struct net *net, 110 const struct sctp_endpoint *ep, 111 const struct sctp_association *asoc, 112 void *arg, 113 struct sctp_cmd_seq *commands, 114 const __u8 *payload, 115 const size_t paylen); 116 117 static enum sctp_disposition sctp_sf_violation_chunklen( 118 struct net *net, 119 const struct sctp_endpoint *ep, 120 const struct sctp_association *asoc, 121 const union sctp_subtype type, 122 void *arg, 123 struct sctp_cmd_seq *commands); 124 125 static enum sctp_disposition sctp_sf_violation_paramlen( 126 struct net *net, 127 const struct sctp_endpoint *ep, 128 const struct sctp_association *asoc, 129 const union sctp_subtype type, 130 void *arg, void *ext, 131 struct sctp_cmd_seq *commands); 132 133 static enum sctp_disposition sctp_sf_violation_ctsn( 134 struct net *net, 135 const struct sctp_endpoint *ep, 136 const struct sctp_association *asoc, 137 const union sctp_subtype type, 138 void *arg, 139 struct sctp_cmd_seq *commands); 140 141 static enum sctp_disposition sctp_sf_violation_chunk( 142 struct net *net, 143 const struct sctp_endpoint *ep, 144 const struct sctp_association *asoc, 145 const union sctp_subtype type, 146 void *arg, 147 struct sctp_cmd_seq *commands); 148 149 static enum sctp_ierror sctp_sf_authenticate( 150 const struct sctp_association *asoc, 151 struct sctp_chunk *chunk); 152 153 static enum sctp_disposition __sctp_sf_do_9_1_abort( 154 struct net *net, 155 const struct sctp_endpoint *ep, 156 const struct sctp_association *asoc, 157 const union sctp_subtype type, 158 void *arg, 159 struct sctp_cmd_seq *commands); 160 161 static enum sctp_disposition 162 __sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep, 163 const struct sctp_association *asoc, 164 const union sctp_subtype type, void *arg, 165 struct sctp_cmd_seq *commands); 166 167 /* Small helper function that checks if the chunk length 168 * is of the appropriate length. The 'required_length' argument 169 * is set to be the size of a specific chunk we are testing. 170 * Return Values: true = Valid length 171 * false = Invalid length 172 * 173 */ 174 static inline bool sctp_chunk_length_valid(struct sctp_chunk *chunk, 175 __u16 required_length) 176 { 177 __u16 chunk_length = ntohs(chunk->chunk_hdr->length); 178 179 /* Previously already marked? */ 180 if (unlikely(chunk->pdiscard)) 181 return false; 182 if (unlikely(chunk_length < required_length)) 183 return false; 184 185 return true; 186 } 187 188 /* Check for format error in an ABORT chunk */ 189 static inline bool sctp_err_chunk_valid(struct sctp_chunk *chunk) 190 { 191 struct sctp_errhdr *err; 192 193 sctp_walk_errors(err, chunk->chunk_hdr); 194 195 return (void *)err == (void *)chunk->chunk_end; 196 } 197 198 /********************************************************** 199 * These are the state functions for handling chunk events. 200 **********************************************************/ 201 202 /* 203 * Process the final SHUTDOWN COMPLETE. 204 * 205 * Section: 4 (C) (diagram), 9.2 206 * Upon reception of the SHUTDOWN COMPLETE chunk the endpoint will verify 207 * that it is in SHUTDOWN-ACK-SENT state, if it is not the chunk should be 208 * discarded. If the endpoint is in the SHUTDOWN-ACK-SENT state the endpoint 209 * should stop the T2-shutdown timer and remove all knowledge of the 210 * association (and thus the association enters the CLOSED state). 211 * 212 * Verification Tag: 8.5.1(C), sctpimpguide 2.41. 213 * C) Rules for packet carrying SHUTDOWN COMPLETE: 214 * ... 215 * - The receiver of a SHUTDOWN COMPLETE shall accept the packet 216 * if the Verification Tag field of the packet matches its own tag and 217 * the T bit is not set 218 * OR 219 * it is set to its peer's tag and the T bit is set in the Chunk 220 * Flags. 221 * Otherwise, the receiver MUST silently discard the packet 222 * and take no further action. An endpoint MUST ignore the 223 * SHUTDOWN COMPLETE if it is not in the SHUTDOWN-ACK-SENT state. 224 * 225 * Inputs 226 * (endpoint, asoc, chunk) 227 * 228 * Outputs 229 * (asoc, reply_msg, msg_up, timers, counters) 230 * 231 * The return value is the disposition of the chunk. 232 */ 233 enum sctp_disposition sctp_sf_do_4_C(struct net *net, 234 const struct sctp_endpoint *ep, 235 const struct sctp_association *asoc, 236 const union sctp_subtype type, 237 void *arg, struct sctp_cmd_seq *commands) 238 { 239 struct sctp_chunk *chunk = arg; 240 struct sctp_ulpevent *ev; 241 242 if (!sctp_vtag_verify_either(chunk, asoc)) 243 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 244 245 /* RFC 2960 6.10 Bundling 246 * 247 * An endpoint MUST NOT bundle INIT, INIT ACK or 248 * SHUTDOWN COMPLETE with any other chunks. 249 */ 250 if (!chunk->singleton) 251 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 252 253 /* Make sure that the SHUTDOWN_COMPLETE chunk has a valid length. */ 254 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 255 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 256 commands); 257 258 /* RFC 2960 10.2 SCTP-to-ULP 259 * 260 * H) SHUTDOWN COMPLETE notification 261 * 262 * When SCTP completes the shutdown procedures (section 9.2) this 263 * notification is passed to the upper layer. 264 */ 265 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 266 0, 0, 0, NULL, GFP_ATOMIC); 267 if (ev) 268 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 269 SCTP_ULPEVENT(ev)); 270 271 /* Upon reception of the SHUTDOWN COMPLETE chunk the endpoint 272 * will verify that it is in SHUTDOWN-ACK-SENT state, if it is 273 * not the chunk should be discarded. If the endpoint is in 274 * the SHUTDOWN-ACK-SENT state the endpoint should stop the 275 * T2-shutdown timer and remove all knowledge of the 276 * association (and thus the association enters the CLOSED 277 * state). 278 */ 279 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 280 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 281 282 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 283 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 284 285 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 286 SCTP_STATE(SCTP_STATE_CLOSED)); 287 288 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 289 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 290 291 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 292 293 return SCTP_DISPOSITION_DELETE_TCB; 294 } 295 296 /* 297 * Respond to a normal INIT chunk. 298 * We are the side that is being asked for an association. 299 * 300 * Section: 5.1 Normal Establishment of an Association, B 301 * B) "Z" shall respond immediately with an INIT ACK chunk. The 302 * destination IP address of the INIT ACK MUST be set to the source 303 * IP address of the INIT to which this INIT ACK is responding. In 304 * the response, besides filling in other parameters, "Z" must set the 305 * Verification Tag field to Tag_A, and also provide its own 306 * Verification Tag (Tag_Z) in the Initiate Tag field. 307 * 308 * Verification Tag: Must be 0. 309 * 310 * Inputs 311 * (endpoint, asoc, chunk) 312 * 313 * Outputs 314 * (asoc, reply_msg, msg_up, timers, counters) 315 * 316 * The return value is the disposition of the chunk. 317 */ 318 enum sctp_disposition sctp_sf_do_5_1B_init(struct net *net, 319 const struct sctp_endpoint *ep, 320 const struct sctp_association *asoc, 321 const union sctp_subtype type, 322 void *arg, 323 struct sctp_cmd_seq *commands) 324 { 325 struct sctp_chunk *chunk = arg, *repl, *err_chunk; 326 struct sctp_unrecognized_param *unk_param; 327 struct sctp_association *new_asoc; 328 struct sctp_packet *packet; 329 int len; 330 331 /* 6.10 Bundling 332 * An endpoint MUST NOT bundle INIT, INIT ACK or 333 * SHUTDOWN COMPLETE with any other chunks. 334 * 335 * IG Section 2.11.2 336 * Furthermore, we require that the receiver of an INIT chunk MUST 337 * enforce these rules by silently discarding an arriving packet 338 * with an INIT chunk that is bundled with other chunks. 339 */ 340 if (!chunk->singleton) 341 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 342 343 /* Make sure that the INIT chunk has a valid length. 344 * Normally, this would cause an ABORT with a Protocol Violation 345 * error, but since we don't have an association, we'll 346 * just discard the packet. 347 */ 348 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk))) 349 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 350 351 /* If the packet is an OOTB packet which is temporarily on the 352 * control endpoint, respond with an ABORT. 353 */ 354 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 355 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 356 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 357 } 358 359 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 360 * Tag. 361 */ 362 if (chunk->sctp_hdr->vtag != 0) 363 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 364 365 /* If the INIT is coming toward a closing socket, we'll send back 366 * and ABORT. Essentially, this catches the race of INIT being 367 * backloged to the socket at the same time as the user issues close(). 368 * Since the socket and all its associations are going away, we 369 * can treat this OOTB 370 */ 371 if (sctp_sstate(ep->base.sk, CLOSING)) 372 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 373 374 /* Verify the INIT chunk before processing it. */ 375 err_chunk = NULL; 376 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 377 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 378 &err_chunk)) { 379 /* This chunk contains fatal error. It is to be discarded. 380 * Send an ABORT, with causes if there is any. 381 */ 382 if (err_chunk) { 383 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 384 (__u8 *)(err_chunk->chunk_hdr) + 385 sizeof(struct sctp_chunkhdr), 386 ntohs(err_chunk->chunk_hdr->length) - 387 sizeof(struct sctp_chunkhdr)); 388 389 sctp_chunk_free(err_chunk); 390 391 if (packet) { 392 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 393 SCTP_PACKET(packet)); 394 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 395 return SCTP_DISPOSITION_CONSUME; 396 } else { 397 return SCTP_DISPOSITION_NOMEM; 398 } 399 } else { 400 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 401 commands); 402 } 403 } 404 405 /* Grab the INIT header. */ 406 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 407 408 /* Tag the variable length parameters. */ 409 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 410 411 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 412 if (!new_asoc) 413 goto nomem; 414 415 /* Update socket peer label if first association. */ 416 if (security_sctp_assoc_request(new_asoc, chunk->skb)) { 417 sctp_association_free(new_asoc); 418 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 419 } 420 421 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 422 sctp_scope(sctp_source(chunk)), 423 GFP_ATOMIC) < 0) 424 goto nomem_init; 425 426 /* The call, sctp_process_init(), can fail on memory allocation. */ 427 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 428 (struct sctp_init_chunk *)chunk->chunk_hdr, 429 GFP_ATOMIC)) 430 goto nomem_init; 431 432 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 433 434 /* If there are errors need to be reported for unknown parameters, 435 * make sure to reserve enough room in the INIT ACK for them. 436 */ 437 len = 0; 438 if (err_chunk) 439 len = ntohs(err_chunk->chunk_hdr->length) - 440 sizeof(struct sctp_chunkhdr); 441 442 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 443 if (!repl) 444 goto nomem_init; 445 446 /* If there are errors need to be reported for unknown parameters, 447 * include them in the outgoing INIT ACK as "Unrecognized parameter" 448 * parameter. 449 */ 450 if (err_chunk) { 451 /* Get the "Unrecognized parameter" parameter(s) out of the 452 * ERROR chunk generated by sctp_verify_init(). Since the 453 * error cause code for "unknown parameter" and the 454 * "Unrecognized parameter" type is the same, we can 455 * construct the parameters in INIT ACK by copying the 456 * ERROR causes over. 457 */ 458 unk_param = (struct sctp_unrecognized_param *) 459 ((__u8 *)(err_chunk->chunk_hdr) + 460 sizeof(struct sctp_chunkhdr)); 461 /* Replace the cause code with the "Unrecognized parameter" 462 * parameter type. 463 */ 464 sctp_addto_chunk(repl, len, unk_param); 465 sctp_chunk_free(err_chunk); 466 } 467 468 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 469 470 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 471 472 /* 473 * Note: After sending out INIT ACK with the State Cookie parameter, 474 * "Z" MUST NOT allocate any resources, nor keep any states for the 475 * new association. Otherwise, "Z" will be vulnerable to resource 476 * attacks. 477 */ 478 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 479 480 return SCTP_DISPOSITION_DELETE_TCB; 481 482 nomem_init: 483 sctp_association_free(new_asoc); 484 nomem: 485 if (err_chunk) 486 sctp_chunk_free(err_chunk); 487 return SCTP_DISPOSITION_NOMEM; 488 } 489 490 /* 491 * Respond to a normal INIT ACK chunk. 492 * We are the side that is initiating the association. 493 * 494 * Section: 5.1 Normal Establishment of an Association, C 495 * C) Upon reception of the INIT ACK from "Z", "A" shall stop the T1-init 496 * timer and leave COOKIE-WAIT state. "A" shall then send the State 497 * Cookie received in the INIT ACK chunk in a COOKIE ECHO chunk, start 498 * the T1-cookie timer, and enter the COOKIE-ECHOED state. 499 * 500 * Note: The COOKIE ECHO chunk can be bundled with any pending outbound 501 * DATA chunks, but it MUST be the first chunk in the packet and 502 * until the COOKIE ACK is returned the sender MUST NOT send any 503 * other packets to the peer. 504 * 505 * Verification Tag: 3.3.3 506 * If the value of the Initiate Tag in a received INIT ACK chunk is 507 * found to be 0, the receiver MUST treat it as an error and close the 508 * association by transmitting an ABORT. 509 * 510 * Inputs 511 * (endpoint, asoc, chunk) 512 * 513 * Outputs 514 * (asoc, reply_msg, msg_up, timers, counters) 515 * 516 * The return value is the disposition of the chunk. 517 */ 518 enum sctp_disposition sctp_sf_do_5_1C_ack(struct net *net, 519 const struct sctp_endpoint *ep, 520 const struct sctp_association *asoc, 521 const union sctp_subtype type, 522 void *arg, 523 struct sctp_cmd_seq *commands) 524 { 525 struct sctp_init_chunk *initchunk; 526 struct sctp_chunk *chunk = arg; 527 struct sctp_chunk *err_chunk; 528 struct sctp_packet *packet; 529 530 if (!sctp_vtag_verify(chunk, asoc)) 531 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 532 533 /* 6.10 Bundling 534 * An endpoint MUST NOT bundle INIT, INIT ACK or 535 * SHUTDOWN COMPLETE with any other chunks. 536 */ 537 if (!chunk->singleton) 538 return sctp_sf_violation_chunk(net, ep, asoc, type, arg, commands); 539 540 /* Make sure that the INIT-ACK chunk has a valid length */ 541 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_initack_chunk))) 542 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 543 commands); 544 /* Grab the INIT header. */ 545 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 546 547 /* Verify the INIT chunk before processing it. */ 548 err_chunk = NULL; 549 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 550 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 551 &err_chunk)) { 552 553 enum sctp_error error = SCTP_ERROR_NO_RESOURCE; 554 555 /* This chunk contains fatal error. It is to be discarded. 556 * Send an ABORT, with causes. If there are no causes, 557 * then there wasn't enough memory. Just terminate 558 * the association. 559 */ 560 if (err_chunk) { 561 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 562 (__u8 *)(err_chunk->chunk_hdr) + 563 sizeof(struct sctp_chunkhdr), 564 ntohs(err_chunk->chunk_hdr->length) - 565 sizeof(struct sctp_chunkhdr)); 566 567 sctp_chunk_free(err_chunk); 568 569 if (packet) { 570 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 571 SCTP_PACKET(packet)); 572 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 573 error = SCTP_ERROR_INV_PARAM; 574 } 575 } 576 577 /* SCTP-AUTH, Section 6.3: 578 * It should be noted that if the receiver wants to tear 579 * down an association in an authenticated way only, the 580 * handling of malformed packets should not result in 581 * tearing down the association. 582 * 583 * This means that if we only want to abort associations 584 * in an authenticated way (i.e AUTH+ABORT), then we 585 * can't destroy this association just because the packet 586 * was malformed. 587 */ 588 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 589 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 590 591 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 592 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, 593 asoc, chunk->transport); 594 } 595 596 /* Tag the variable length parameters. Note that we never 597 * convert the parameters in an INIT chunk. 598 */ 599 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 600 601 initchunk = (struct sctp_init_chunk *)chunk->chunk_hdr; 602 603 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_INIT, 604 SCTP_PEER_INIT(initchunk)); 605 606 /* SCTP-AUTH: generate the association shared keys so that 607 * we can potentially sign the COOKIE-ECHO. 608 */ 609 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_SHKEY, SCTP_NULL()); 610 611 /* Reset init error count upon receipt of INIT-ACK. */ 612 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 613 614 /* 5.1 C) "A" shall stop the T1-init timer and leave 615 * COOKIE-WAIT state. "A" shall then ... start the T1-cookie 616 * timer, and enter the COOKIE-ECHOED state. 617 */ 618 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 619 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 620 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 621 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 622 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 623 SCTP_STATE(SCTP_STATE_COOKIE_ECHOED)); 624 625 /* 5.1 C) "A" shall then send the State Cookie received in the 626 * INIT ACK chunk in a COOKIE ECHO chunk, ... 627 */ 628 /* If there is any errors to report, send the ERROR chunk generated 629 * for unknown parameters as well. 630 */ 631 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_COOKIE_ECHO, 632 SCTP_CHUNK(err_chunk)); 633 634 return SCTP_DISPOSITION_CONSUME; 635 } 636 637 static bool sctp_auth_chunk_verify(struct net *net, struct sctp_chunk *chunk, 638 const struct sctp_association *asoc) 639 { 640 struct sctp_chunk auth; 641 642 if (!chunk->auth_chunk) 643 return true; 644 645 /* SCTP-AUTH: auth_chunk pointer is only set when the cookie-echo 646 * is supposed to be authenticated and we have to do delayed 647 * authentication. We've just recreated the association using 648 * the information in the cookie and now it's much easier to 649 * do the authentication. 650 */ 651 652 /* Make sure that we and the peer are AUTH capable */ 653 if (!net->sctp.auth_enable || !asoc->peer.auth_capable) 654 return false; 655 656 /* set-up our fake chunk so that we can process it */ 657 auth.skb = chunk->auth_chunk; 658 auth.asoc = chunk->asoc; 659 auth.sctp_hdr = chunk->sctp_hdr; 660 auth.chunk_hdr = (struct sctp_chunkhdr *) 661 skb_push(chunk->auth_chunk, 662 sizeof(struct sctp_chunkhdr)); 663 skb_pull(chunk->auth_chunk, sizeof(struct sctp_chunkhdr)); 664 auth.transport = chunk->transport; 665 666 return sctp_sf_authenticate(asoc, &auth) == SCTP_IERROR_NO_ERROR; 667 } 668 669 /* 670 * Respond to a normal COOKIE ECHO chunk. 671 * We are the side that is being asked for an association. 672 * 673 * Section: 5.1 Normal Establishment of an Association, D 674 * D) Upon reception of the COOKIE ECHO chunk, Endpoint "Z" will reply 675 * with a COOKIE ACK chunk after building a TCB and moving to 676 * the ESTABLISHED state. A COOKIE ACK chunk may be bundled with 677 * any pending DATA chunks (and/or SACK chunks), but the COOKIE ACK 678 * chunk MUST be the first chunk in the packet. 679 * 680 * IMPLEMENTATION NOTE: An implementation may choose to send the 681 * Communication Up notification to the SCTP user upon reception 682 * of a valid COOKIE ECHO chunk. 683 * 684 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 685 * D) Rules for packet carrying a COOKIE ECHO 686 * 687 * - When sending a COOKIE ECHO, the endpoint MUST use the value of the 688 * Initial Tag received in the INIT ACK. 689 * 690 * - The receiver of a COOKIE ECHO follows the procedures in Section 5. 691 * 692 * Inputs 693 * (endpoint, asoc, chunk) 694 * 695 * Outputs 696 * (asoc, reply_msg, msg_up, timers, counters) 697 * 698 * The return value is the disposition of the chunk. 699 */ 700 enum sctp_disposition sctp_sf_do_5_1D_ce(struct net *net, 701 const struct sctp_endpoint *ep, 702 const struct sctp_association *asoc, 703 const union sctp_subtype type, 704 void *arg, 705 struct sctp_cmd_seq *commands) 706 { 707 struct sctp_ulpevent *ev, *ai_ev = NULL, *auth_ev = NULL; 708 struct sctp_association *new_asoc; 709 struct sctp_init_chunk *peer_init; 710 struct sctp_chunk *chunk = arg; 711 struct sctp_chunk *err_chk_p; 712 struct sctp_chunk *repl; 713 struct sock *sk; 714 int error = 0; 715 716 if (asoc && !sctp_vtag_verify(chunk, asoc)) 717 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 718 719 /* If the packet is an OOTB packet which is temporarily on the 720 * control endpoint, respond with an ABORT. 721 */ 722 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) { 723 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 724 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 725 } 726 727 /* Make sure that the COOKIE_ECHO chunk has a valid length. 728 * In this case, we check that we have enough for at least a 729 * chunk header. More detailed verification is done 730 * in sctp_unpack_cookie(). 731 */ 732 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 733 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 734 commands); 735 736 /* If the endpoint is not listening or if the number of associations 737 * on the TCP-style socket exceed the max backlog, respond with an 738 * ABORT. 739 */ 740 sk = ep->base.sk; 741 if (!sctp_sstate(sk, LISTENING) || 742 (sctp_style(sk, TCP) && sk_acceptq_is_full(sk))) 743 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 744 745 /* "Decode" the chunk. We have no optional parameters so we 746 * are in good shape. 747 */ 748 chunk->subh.cookie_hdr = 749 (struct sctp_signed_cookie *)chunk->skb->data; 750 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 751 sizeof(struct sctp_chunkhdr))) 752 goto nomem; 753 754 /* 5.1 D) Upon reception of the COOKIE ECHO chunk, Endpoint 755 * "Z" will reply with a COOKIE ACK chunk after building a TCB 756 * and moving to the ESTABLISHED state. 757 */ 758 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 759 &err_chk_p); 760 761 /* FIXME: 762 * If the re-build failed, what is the proper error path 763 * from here? 764 * 765 * [We should abort the association. --piggy] 766 */ 767 if (!new_asoc) { 768 /* FIXME: Several errors are possible. A bad cookie should 769 * be silently discarded, but think about logging it too. 770 */ 771 switch (error) { 772 case -SCTP_IERROR_NOMEM: 773 goto nomem; 774 775 case -SCTP_IERROR_STALE_COOKIE: 776 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 777 err_chk_p); 778 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 779 780 case -SCTP_IERROR_BAD_SIG: 781 default: 782 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 783 } 784 } 785 786 if (security_sctp_assoc_request(new_asoc, chunk->head_skb ?: chunk->skb)) { 787 sctp_association_free(new_asoc); 788 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 789 } 790 791 /* Delay state machine commands until later. 792 * 793 * Re-build the bind address for the association is done in 794 * the sctp_unpack_cookie() already. 795 */ 796 /* This is a brand-new association, so these are not yet side 797 * effects--it is safe to run them here. 798 */ 799 peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1); 800 if (!sctp_process_init(new_asoc, chunk, 801 &chunk->subh.cookie_hdr->c.peer_addr, 802 peer_init, GFP_ATOMIC)) 803 goto nomem_init; 804 805 /* SCTP-AUTH: Now that we've populate required fields in 806 * sctp_process_init, set up the association shared keys as 807 * necessary so that we can potentially authenticate the ACK 808 */ 809 error = sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC); 810 if (error) 811 goto nomem_init; 812 813 if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) { 814 sctp_association_free(new_asoc); 815 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 816 } 817 818 repl = sctp_make_cookie_ack(new_asoc, chunk); 819 if (!repl) 820 goto nomem_init; 821 822 /* RFC 2960 5.1 Normal Establishment of an Association 823 * 824 * D) IMPLEMENTATION NOTE: An implementation may choose to 825 * send the Communication Up notification to the SCTP user 826 * upon reception of a valid COOKIE ECHO chunk. 827 */ 828 ev = sctp_ulpevent_make_assoc_change(new_asoc, 0, SCTP_COMM_UP, 0, 829 new_asoc->c.sinit_num_ostreams, 830 new_asoc->c.sinit_max_instreams, 831 NULL, GFP_ATOMIC); 832 if (!ev) 833 goto nomem_ev; 834 835 /* Sockets API Draft Section 5.3.1.6 836 * When a peer sends a Adaptation Layer Indication parameter , SCTP 837 * delivers this notification to inform the application that of the 838 * peers requested adaptation layer. 839 */ 840 if (new_asoc->peer.adaptation_ind) { 841 ai_ev = sctp_ulpevent_make_adaptation_indication(new_asoc, 842 GFP_ATOMIC); 843 if (!ai_ev) 844 goto nomem_aiev; 845 } 846 847 if (!new_asoc->peer.auth_capable) { 848 auth_ev = sctp_ulpevent_make_authkey(new_asoc, 0, 849 SCTP_AUTH_NO_AUTH, 850 GFP_ATOMIC); 851 if (!auth_ev) 852 goto nomem_authev; 853 } 854 855 /* Add all the state machine commands now since we've created 856 * everything. This way we don't introduce memory corruptions 857 * during side-effect processing and correctly count established 858 * associations. 859 */ 860 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 861 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 862 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 863 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 864 SCTP_INC_STATS(net, SCTP_MIB_PASSIVEESTABS); 865 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 866 867 if (new_asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 868 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 869 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 870 871 /* This will send the COOKIE ACK */ 872 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 873 874 /* Queue the ASSOC_CHANGE event */ 875 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 876 877 /* Send up the Adaptation Layer Indication event */ 878 if (ai_ev) 879 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 880 SCTP_ULPEVENT(ai_ev)); 881 882 if (auth_ev) 883 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 884 SCTP_ULPEVENT(auth_ev)); 885 886 return SCTP_DISPOSITION_CONSUME; 887 888 nomem_authev: 889 if (ai_ev) 890 sctp_ulpevent_free(ai_ev); 891 nomem_aiev: 892 sctp_ulpevent_free(ev); 893 nomem_ev: 894 sctp_chunk_free(repl); 895 nomem_init: 896 sctp_association_free(new_asoc); 897 nomem: 898 return SCTP_DISPOSITION_NOMEM; 899 } 900 901 /* 902 * Respond to a normal COOKIE ACK chunk. 903 * We are the side that is asking for an association. 904 * 905 * RFC 2960 5.1 Normal Establishment of an Association 906 * 907 * E) Upon reception of the COOKIE ACK, endpoint "A" will move from the 908 * COOKIE-ECHOED state to the ESTABLISHED state, stopping the T1-cookie 909 * timer. It may also notify its ULP about the successful 910 * establishment of the association with a Communication Up 911 * notification (see Section 10). 912 * 913 * Verification Tag: 914 * Inputs 915 * (endpoint, asoc, chunk) 916 * 917 * Outputs 918 * (asoc, reply_msg, msg_up, timers, counters) 919 * 920 * The return value is the disposition of the chunk. 921 */ 922 enum sctp_disposition sctp_sf_do_5_1E_ca(struct net *net, 923 const struct sctp_endpoint *ep, 924 const struct sctp_association *asoc, 925 const union sctp_subtype type, 926 void *arg, 927 struct sctp_cmd_seq *commands) 928 { 929 struct sctp_chunk *chunk = arg; 930 struct sctp_ulpevent *ev; 931 932 if (!sctp_vtag_verify(chunk, asoc)) 933 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 934 935 /* Set peer label for connection. */ 936 if (security_sctp_assoc_established((struct sctp_association *)asoc, 937 chunk->head_skb ?: chunk->skb)) 938 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 939 940 /* Verify that the chunk length for the COOKIE-ACK is OK. 941 * If we don't do this, any bundled chunks may be junked. 942 */ 943 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 944 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 945 commands); 946 947 /* Reset init error count upon receipt of COOKIE-ACK, 948 * to avoid problems with the management of this 949 * counter in stale cookie situations when a transition back 950 * from the COOKIE-ECHOED state to the COOKIE-WAIT 951 * state is performed. 952 */ 953 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_RESET, SCTP_NULL()); 954 955 /* RFC 2960 5.1 Normal Establishment of an Association 956 * 957 * E) Upon reception of the COOKIE ACK, endpoint "A" will move 958 * from the COOKIE-ECHOED state to the ESTABLISHED state, 959 * stopping the T1-cookie timer. 960 */ 961 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 962 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 963 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 964 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 965 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 966 SCTP_INC_STATS(net, SCTP_MIB_ACTIVEESTABS); 967 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 968 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 969 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 970 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 971 972 /* It may also notify its ULP about the successful 973 * establishment of the association with a Communication Up 974 * notification (see Section 10). 975 */ 976 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_COMM_UP, 977 0, asoc->c.sinit_num_ostreams, 978 asoc->c.sinit_max_instreams, 979 NULL, GFP_ATOMIC); 980 981 if (!ev) 982 goto nomem; 983 984 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 985 986 /* Sockets API Draft Section 5.3.1.6 987 * When a peer sends a Adaptation Layer Indication parameter , SCTP 988 * delivers this notification to inform the application that of the 989 * peers requested adaptation layer. 990 */ 991 if (asoc->peer.adaptation_ind) { 992 ev = sctp_ulpevent_make_adaptation_indication(asoc, GFP_ATOMIC); 993 if (!ev) 994 goto nomem; 995 996 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 997 SCTP_ULPEVENT(ev)); 998 } 999 1000 if (!asoc->peer.auth_capable) { 1001 ev = sctp_ulpevent_make_authkey(asoc, 0, SCTP_AUTH_NO_AUTH, 1002 GFP_ATOMIC); 1003 if (!ev) 1004 goto nomem; 1005 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 1006 SCTP_ULPEVENT(ev)); 1007 } 1008 1009 return SCTP_DISPOSITION_CONSUME; 1010 nomem: 1011 return SCTP_DISPOSITION_NOMEM; 1012 } 1013 1014 /* Generate and sendout a heartbeat packet. */ 1015 static enum sctp_disposition sctp_sf_heartbeat( 1016 const struct sctp_endpoint *ep, 1017 const struct sctp_association *asoc, 1018 const union sctp_subtype type, 1019 void *arg, 1020 struct sctp_cmd_seq *commands) 1021 { 1022 struct sctp_transport *transport = (struct sctp_transport *) arg; 1023 struct sctp_chunk *reply; 1024 1025 /* Send a heartbeat to our peer. */ 1026 reply = sctp_make_heartbeat(asoc, transport, 0); 1027 if (!reply) 1028 return SCTP_DISPOSITION_NOMEM; 1029 1030 /* Set rto_pending indicating that an RTT measurement 1031 * is started with this heartbeat chunk. 1032 */ 1033 sctp_add_cmd_sf(commands, SCTP_CMD_RTO_PENDING, 1034 SCTP_TRANSPORT(transport)); 1035 1036 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1037 return SCTP_DISPOSITION_CONSUME; 1038 } 1039 1040 /* Generate a HEARTBEAT packet on the given transport. */ 1041 enum sctp_disposition sctp_sf_sendbeat_8_3(struct net *net, 1042 const struct sctp_endpoint *ep, 1043 const struct sctp_association *asoc, 1044 const union sctp_subtype type, 1045 void *arg, 1046 struct sctp_cmd_seq *commands) 1047 { 1048 struct sctp_transport *transport = (struct sctp_transport *) arg; 1049 1050 if (asoc->overall_error_count >= asoc->max_retrans) { 1051 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 1052 SCTP_ERROR(ETIMEDOUT)); 1053 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 1054 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 1055 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 1056 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 1057 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 1058 return SCTP_DISPOSITION_DELETE_TCB; 1059 } 1060 1061 /* Section 3.3.5. 1062 * The Sender-specific Heartbeat Info field should normally include 1063 * information about the sender's current time when this HEARTBEAT 1064 * chunk is sent and the destination transport address to which this 1065 * HEARTBEAT is sent (see Section 8.3). 1066 */ 1067 1068 if (transport->param_flags & SPP_HB_ENABLE) { 1069 if (SCTP_DISPOSITION_NOMEM == 1070 sctp_sf_heartbeat(ep, asoc, type, arg, 1071 commands)) 1072 return SCTP_DISPOSITION_NOMEM; 1073 1074 /* Set transport error counter and association error counter 1075 * when sending heartbeat. 1076 */ 1077 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 1078 SCTP_TRANSPORT(transport)); 1079 } 1080 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_IDLE, 1081 SCTP_TRANSPORT(transport)); 1082 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMER_UPDATE, 1083 SCTP_TRANSPORT(transport)); 1084 1085 return SCTP_DISPOSITION_CONSUME; 1086 } 1087 1088 /* resend asoc strreset_chunk. */ 1089 enum sctp_disposition sctp_sf_send_reconf(struct net *net, 1090 const struct sctp_endpoint *ep, 1091 const struct sctp_association *asoc, 1092 const union sctp_subtype type, 1093 void *arg, 1094 struct sctp_cmd_seq *commands) 1095 { 1096 struct sctp_transport *transport = arg; 1097 1098 if (asoc->overall_error_count >= asoc->max_retrans) { 1099 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 1100 SCTP_ERROR(ETIMEDOUT)); 1101 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 1102 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 1103 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 1104 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 1105 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 1106 return SCTP_DISPOSITION_DELETE_TCB; 1107 } 1108 1109 sctp_chunk_hold(asoc->strreset_chunk); 1110 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1111 SCTP_CHUNK(asoc->strreset_chunk)); 1112 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 1113 1114 return SCTP_DISPOSITION_CONSUME; 1115 } 1116 1117 /* send hb chunk with padding for PLPMUTD. */ 1118 enum sctp_disposition sctp_sf_send_probe(struct net *net, 1119 const struct sctp_endpoint *ep, 1120 const struct sctp_association *asoc, 1121 const union sctp_subtype type, 1122 void *arg, 1123 struct sctp_cmd_seq *commands) 1124 { 1125 struct sctp_transport *transport = (struct sctp_transport *)arg; 1126 struct sctp_chunk *reply; 1127 1128 if (!sctp_transport_pl_enabled(transport)) 1129 return SCTP_DISPOSITION_CONSUME; 1130 1131 sctp_transport_pl_send(transport); 1132 reply = sctp_make_heartbeat(asoc, transport, transport->pl.probe_size); 1133 if (!reply) 1134 return SCTP_DISPOSITION_NOMEM; 1135 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1136 sctp_add_cmd_sf(commands, SCTP_CMD_PROBE_TIMER_UPDATE, 1137 SCTP_TRANSPORT(transport)); 1138 1139 return SCTP_DISPOSITION_CONSUME; 1140 } 1141 1142 /* 1143 * Process an heartbeat request. 1144 * 1145 * Section: 8.3 Path Heartbeat 1146 * The receiver of the HEARTBEAT should immediately respond with a 1147 * HEARTBEAT ACK that contains the Heartbeat Information field copied 1148 * from the received HEARTBEAT chunk. 1149 * 1150 * Verification Tag: 8.5 Verification Tag [Normal verification] 1151 * When receiving an SCTP packet, the endpoint MUST ensure that the 1152 * value in the Verification Tag field of the received SCTP packet 1153 * matches its own Tag. If the received Verification Tag value does not 1154 * match the receiver's own tag value, the receiver shall silently 1155 * discard the packet and shall not process it any further except for 1156 * those cases listed in Section 8.5.1 below. 1157 * 1158 * Inputs 1159 * (endpoint, asoc, chunk) 1160 * 1161 * Outputs 1162 * (asoc, reply_msg, msg_up, timers, counters) 1163 * 1164 * The return value is the disposition of the chunk. 1165 */ 1166 enum sctp_disposition sctp_sf_beat_8_3(struct net *net, 1167 const struct sctp_endpoint *ep, 1168 const struct sctp_association *asoc, 1169 const union sctp_subtype type, 1170 void *arg, struct sctp_cmd_seq *commands) 1171 { 1172 struct sctp_paramhdr *param_hdr; 1173 struct sctp_chunk *chunk = arg; 1174 struct sctp_chunk *reply; 1175 size_t paylen = 0; 1176 1177 if (!sctp_vtag_verify(chunk, asoc)) 1178 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1179 1180 /* Make sure that the HEARTBEAT chunk has a valid length. */ 1181 if (!sctp_chunk_length_valid(chunk, 1182 sizeof(struct sctp_heartbeat_chunk))) 1183 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1184 commands); 1185 1186 /* 8.3 The receiver of the HEARTBEAT should immediately 1187 * respond with a HEARTBEAT ACK that contains the Heartbeat 1188 * Information field copied from the received HEARTBEAT chunk. 1189 */ 1190 chunk->subh.hb_hdr = (struct sctp_heartbeathdr *)chunk->skb->data; 1191 param_hdr = (struct sctp_paramhdr *)chunk->subh.hb_hdr; 1192 paylen = ntohs(chunk->chunk_hdr->length) - sizeof(struct sctp_chunkhdr); 1193 1194 if (ntohs(param_hdr->length) > paylen) 1195 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 1196 param_hdr, commands); 1197 1198 if (!pskb_pull(chunk->skb, paylen)) 1199 goto nomem; 1200 1201 reply = sctp_make_heartbeat_ack(asoc, chunk, param_hdr, paylen); 1202 if (!reply) 1203 goto nomem; 1204 1205 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 1206 return SCTP_DISPOSITION_CONSUME; 1207 1208 nomem: 1209 return SCTP_DISPOSITION_NOMEM; 1210 } 1211 1212 /* 1213 * Process the returning HEARTBEAT ACK. 1214 * 1215 * Section: 8.3 Path Heartbeat 1216 * Upon the receipt of the HEARTBEAT ACK, the sender of the HEARTBEAT 1217 * should clear the error counter of the destination transport 1218 * address to which the HEARTBEAT was sent, and mark the destination 1219 * transport address as active if it is not so marked. The endpoint may 1220 * optionally report to the upper layer when an inactive destination 1221 * address is marked as active due to the reception of the latest 1222 * HEARTBEAT ACK. The receiver of the HEARTBEAT ACK must also 1223 * clear the association overall error count as well (as defined 1224 * in section 8.1). 1225 * 1226 * The receiver of the HEARTBEAT ACK should also perform an RTT 1227 * measurement for that destination transport address using the time 1228 * value carried in the HEARTBEAT ACK chunk. 1229 * 1230 * Verification Tag: 8.5 Verification Tag [Normal verification] 1231 * 1232 * Inputs 1233 * (endpoint, asoc, chunk) 1234 * 1235 * Outputs 1236 * (asoc, reply_msg, msg_up, timers, counters) 1237 * 1238 * The return value is the disposition of the chunk. 1239 */ 1240 enum sctp_disposition sctp_sf_backbeat_8_3(struct net *net, 1241 const struct sctp_endpoint *ep, 1242 const struct sctp_association *asoc, 1243 const union sctp_subtype type, 1244 void *arg, 1245 struct sctp_cmd_seq *commands) 1246 { 1247 struct sctp_sender_hb_info *hbinfo; 1248 struct sctp_chunk *chunk = arg; 1249 struct sctp_transport *link; 1250 unsigned long max_interval; 1251 union sctp_addr from_addr; 1252 1253 if (!sctp_vtag_verify(chunk, asoc)) 1254 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1255 1256 /* Make sure that the HEARTBEAT-ACK chunk has a valid length. */ 1257 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr) + 1258 sizeof(*hbinfo))) 1259 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 1260 commands); 1261 1262 hbinfo = (struct sctp_sender_hb_info *)chunk->skb->data; 1263 /* Make sure that the length of the parameter is what we expect */ 1264 if (ntohs(hbinfo->param_hdr.length) != sizeof(*hbinfo)) 1265 return SCTP_DISPOSITION_DISCARD; 1266 1267 from_addr = hbinfo->daddr; 1268 link = sctp_assoc_lookup_paddr(asoc, &from_addr); 1269 1270 /* This should never happen, but lets log it if so. */ 1271 if (unlikely(!link)) { 1272 if (from_addr.sa.sa_family == AF_INET6) { 1273 net_warn_ratelimited("%s association %p could not find address %pI6\n", 1274 __func__, 1275 asoc, 1276 &from_addr.v6.sin6_addr); 1277 } else { 1278 net_warn_ratelimited("%s association %p could not find address %pI4\n", 1279 __func__, 1280 asoc, 1281 &from_addr.v4.sin_addr.s_addr); 1282 } 1283 return SCTP_DISPOSITION_DISCARD; 1284 } 1285 1286 /* Validate the 64-bit random nonce. */ 1287 if (hbinfo->hb_nonce != link->hb_nonce) 1288 return SCTP_DISPOSITION_DISCARD; 1289 1290 if (hbinfo->probe_size) { 1291 if (hbinfo->probe_size != link->pl.probe_size || 1292 !sctp_transport_pl_enabled(link)) 1293 return SCTP_DISPOSITION_DISCARD; 1294 1295 if (sctp_transport_pl_recv(link)) 1296 return SCTP_DISPOSITION_CONSUME; 1297 1298 return sctp_sf_send_probe(net, ep, asoc, type, link, commands); 1299 } 1300 1301 max_interval = link->hbinterval + link->rto; 1302 1303 /* Check if the timestamp looks valid. */ 1304 if (time_after(hbinfo->sent_at, jiffies) || 1305 time_after(jiffies, hbinfo->sent_at + max_interval)) { 1306 pr_debug("%s: HEARTBEAT ACK with invalid timestamp received " 1307 "for transport:%p\n", __func__, link); 1308 1309 return SCTP_DISPOSITION_DISCARD; 1310 } 1311 1312 /* 8.3 Upon the receipt of the HEARTBEAT ACK, the sender of 1313 * the HEARTBEAT should clear the error counter of the 1314 * destination transport address to which the HEARTBEAT was 1315 * sent and mark the destination transport address as active if 1316 * it is not so marked. 1317 */ 1318 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_ON, SCTP_TRANSPORT(link)); 1319 1320 return SCTP_DISPOSITION_CONSUME; 1321 } 1322 1323 /* Helper function to send out an abort for the restart 1324 * condition. 1325 */ 1326 static int sctp_sf_send_restart_abort(struct net *net, union sctp_addr *ssa, 1327 struct sctp_chunk *init, 1328 struct sctp_cmd_seq *commands) 1329 { 1330 struct sctp_af *af = sctp_get_af_specific(ssa->v4.sin_family); 1331 union sctp_addr_param *addrparm; 1332 struct sctp_errhdr *errhdr; 1333 char buffer[sizeof(*errhdr) + sizeof(*addrparm)]; 1334 struct sctp_endpoint *ep; 1335 struct sctp_packet *pkt; 1336 int len; 1337 1338 /* Build the error on the stack. We are way to malloc crazy 1339 * throughout the code today. 1340 */ 1341 errhdr = (struct sctp_errhdr *)buffer; 1342 addrparm = (union sctp_addr_param *)(errhdr + 1); 1343 1344 /* Copy into a parm format. */ 1345 len = af->to_addr_param(ssa, addrparm); 1346 len += sizeof(*errhdr); 1347 1348 errhdr->cause = SCTP_ERROR_RESTART; 1349 errhdr->length = htons(len); 1350 1351 /* Assign to the control socket. */ 1352 ep = sctp_sk(net->sctp.ctl_sock)->ep; 1353 1354 /* Association is NULL since this may be a restart attack and we 1355 * want to send back the attacker's vtag. 1356 */ 1357 pkt = sctp_abort_pkt_new(net, ep, NULL, init, errhdr, len); 1358 1359 if (!pkt) 1360 goto out; 1361 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(pkt)); 1362 1363 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1364 1365 /* Discard the rest of the inbound packet. */ 1366 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 1367 1368 out: 1369 /* Even if there is no memory, treat as a failure so 1370 * the packet will get dropped. 1371 */ 1372 return 0; 1373 } 1374 1375 static bool list_has_sctp_addr(const struct list_head *list, 1376 union sctp_addr *ipaddr) 1377 { 1378 struct sctp_transport *addr; 1379 1380 list_for_each_entry(addr, list, transports) { 1381 if (sctp_cmp_addr_exact(ipaddr, &addr->ipaddr)) 1382 return true; 1383 } 1384 1385 return false; 1386 } 1387 /* A restart is occurring, check to make sure no new addresses 1388 * are being added as we may be under a takeover attack. 1389 */ 1390 static int sctp_sf_check_restart_addrs(const struct sctp_association *new_asoc, 1391 const struct sctp_association *asoc, 1392 struct sctp_chunk *init, 1393 struct sctp_cmd_seq *commands) 1394 { 1395 struct net *net = new_asoc->base.net; 1396 struct sctp_transport *new_addr; 1397 int ret = 1; 1398 1399 /* Implementor's Guide - Section 5.2.2 1400 * ... 1401 * Before responding the endpoint MUST check to see if the 1402 * unexpected INIT adds new addresses to the association. If new 1403 * addresses are added to the association, the endpoint MUST respond 1404 * with an ABORT.. 1405 */ 1406 1407 /* Search through all current addresses and make sure 1408 * we aren't adding any new ones. 1409 */ 1410 list_for_each_entry(new_addr, &new_asoc->peer.transport_addr_list, 1411 transports) { 1412 if (!list_has_sctp_addr(&asoc->peer.transport_addr_list, 1413 &new_addr->ipaddr)) { 1414 sctp_sf_send_restart_abort(net, &new_addr->ipaddr, init, 1415 commands); 1416 ret = 0; 1417 break; 1418 } 1419 } 1420 1421 /* Return success if all addresses were found. */ 1422 return ret; 1423 } 1424 1425 /* Populate the verification/tie tags based on overlapping INIT 1426 * scenario. 1427 * 1428 * Note: Do not use in CLOSED or SHUTDOWN-ACK-SENT state. 1429 */ 1430 static void sctp_tietags_populate(struct sctp_association *new_asoc, 1431 const struct sctp_association *asoc) 1432 { 1433 switch (asoc->state) { 1434 1435 /* 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State */ 1436 1437 case SCTP_STATE_COOKIE_WAIT: 1438 new_asoc->c.my_vtag = asoc->c.my_vtag; 1439 new_asoc->c.my_ttag = asoc->c.my_vtag; 1440 new_asoc->c.peer_ttag = 0; 1441 break; 1442 1443 case SCTP_STATE_COOKIE_ECHOED: 1444 new_asoc->c.my_vtag = asoc->c.my_vtag; 1445 new_asoc->c.my_ttag = asoc->c.my_vtag; 1446 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1447 break; 1448 1449 /* 5.2.2 Unexpected INIT in States Other than CLOSED, COOKIE-ECHOED, 1450 * COOKIE-WAIT and SHUTDOWN-ACK-SENT 1451 */ 1452 default: 1453 new_asoc->c.my_ttag = asoc->c.my_vtag; 1454 new_asoc->c.peer_ttag = asoc->c.peer_vtag; 1455 break; 1456 } 1457 1458 /* Other parameters for the endpoint SHOULD be copied from the 1459 * existing parameters of the association (e.g. number of 1460 * outbound streams) into the INIT ACK and cookie. 1461 */ 1462 new_asoc->rwnd = asoc->rwnd; 1463 new_asoc->c.sinit_num_ostreams = asoc->c.sinit_num_ostreams; 1464 new_asoc->c.sinit_max_instreams = asoc->c.sinit_max_instreams; 1465 new_asoc->c.initial_tsn = asoc->c.initial_tsn; 1466 } 1467 1468 /* 1469 * Compare vtag/tietag values to determine unexpected COOKIE-ECHO 1470 * handling action. 1471 * 1472 * RFC 2960 5.2.4 Handle a COOKIE ECHO when a TCB exists. 1473 * 1474 * Returns value representing action to be taken. These action values 1475 * correspond to Action/Description values in RFC 2960, Table 2. 1476 */ 1477 static char sctp_tietags_compare(struct sctp_association *new_asoc, 1478 const struct sctp_association *asoc) 1479 { 1480 /* In this case, the peer may have restarted. */ 1481 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1482 (asoc->c.peer_vtag != new_asoc->c.peer_vtag) && 1483 (asoc->c.my_vtag == new_asoc->c.my_ttag) && 1484 (asoc->c.peer_vtag == new_asoc->c.peer_ttag)) 1485 return 'A'; 1486 1487 /* Collision case B. */ 1488 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1489 ((asoc->c.peer_vtag != new_asoc->c.peer_vtag) || 1490 (0 == asoc->c.peer_vtag))) { 1491 return 'B'; 1492 } 1493 1494 /* Collision case D. */ 1495 if ((asoc->c.my_vtag == new_asoc->c.my_vtag) && 1496 (asoc->c.peer_vtag == new_asoc->c.peer_vtag)) 1497 return 'D'; 1498 1499 /* Collision case C. */ 1500 if ((asoc->c.my_vtag != new_asoc->c.my_vtag) && 1501 (asoc->c.peer_vtag == new_asoc->c.peer_vtag) && 1502 (0 == new_asoc->c.my_ttag) && 1503 (0 == new_asoc->c.peer_ttag)) 1504 return 'C'; 1505 1506 /* No match to any of the special cases; discard this packet. */ 1507 return 'E'; 1508 } 1509 1510 /* Common helper routine for both duplicate and simultaneous INIT 1511 * chunk handling. 1512 */ 1513 static enum sctp_disposition sctp_sf_do_unexpected_init( 1514 struct net *net, 1515 const struct sctp_endpoint *ep, 1516 const struct sctp_association *asoc, 1517 const union sctp_subtype type, 1518 void *arg, 1519 struct sctp_cmd_seq *commands) 1520 { 1521 struct sctp_chunk *chunk = arg, *repl, *err_chunk; 1522 struct sctp_unrecognized_param *unk_param; 1523 struct sctp_association *new_asoc; 1524 enum sctp_disposition retval; 1525 struct sctp_packet *packet; 1526 int len; 1527 1528 /* 6.10 Bundling 1529 * An endpoint MUST NOT bundle INIT, INIT ACK or 1530 * SHUTDOWN COMPLETE with any other chunks. 1531 * 1532 * IG Section 2.11.2 1533 * Furthermore, we require that the receiver of an INIT chunk MUST 1534 * enforce these rules by silently discarding an arriving packet 1535 * with an INIT chunk that is bundled with other chunks. 1536 */ 1537 if (!chunk->singleton) 1538 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1539 1540 /* Make sure that the INIT chunk has a valid length. */ 1541 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk))) 1542 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1543 1544 /* 3.1 A packet containing an INIT chunk MUST have a zero Verification 1545 * Tag. 1546 */ 1547 if (chunk->sctp_hdr->vtag != 0) 1548 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 1549 1550 if (SCTP_INPUT_CB(chunk->skb)->encap_port != chunk->transport->encap_port) 1551 return sctp_sf_new_encap_port(net, ep, asoc, type, arg, commands); 1552 1553 /* Grab the INIT header. */ 1554 chunk->subh.init_hdr = (struct sctp_inithdr *)chunk->skb->data; 1555 1556 /* Tag the variable length parameters. */ 1557 chunk->param_hdr.v = skb_pull(chunk->skb, sizeof(struct sctp_inithdr)); 1558 1559 if (asoc->state >= SCTP_STATE_ESTABLISHED) { 1560 /* Discard INIT matching peer vtag after handshake completion (stale INIT). */ 1561 if (ntohl(chunk->subh.init_hdr->init_tag) == asoc->peer.i.init_tag) 1562 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1563 } 1564 1565 /* Verify the INIT chunk before processing it. */ 1566 err_chunk = NULL; 1567 if (!sctp_verify_init(net, ep, asoc, chunk->chunk_hdr->type, 1568 (struct sctp_init_chunk *)chunk->chunk_hdr, chunk, 1569 &err_chunk)) { 1570 /* This chunk contains fatal error. It is to be discarded. 1571 * Send an ABORT, with causes if there is any. 1572 */ 1573 if (err_chunk) { 1574 packet = sctp_abort_pkt_new(net, ep, asoc, arg, 1575 (__u8 *)(err_chunk->chunk_hdr) + 1576 sizeof(struct sctp_chunkhdr), 1577 ntohs(err_chunk->chunk_hdr->length) - 1578 sizeof(struct sctp_chunkhdr)); 1579 1580 if (packet) { 1581 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 1582 SCTP_PACKET(packet)); 1583 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 1584 retval = SCTP_DISPOSITION_CONSUME; 1585 } else { 1586 retval = SCTP_DISPOSITION_NOMEM; 1587 } 1588 goto cleanup; 1589 } else { 1590 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, 1591 commands); 1592 } 1593 } 1594 1595 /* 1596 * Other parameters for the endpoint SHOULD be copied from the 1597 * existing parameters of the association (e.g. number of 1598 * outbound streams) into the INIT ACK and cookie. 1599 * FIXME: We are copying parameters from the endpoint not the 1600 * association. 1601 */ 1602 new_asoc = sctp_make_temp_asoc(ep, chunk, GFP_ATOMIC); 1603 if (!new_asoc) 1604 goto nomem; 1605 1606 /* Update socket peer label if first association. */ 1607 if (security_sctp_assoc_request(new_asoc, chunk->skb)) { 1608 sctp_association_free(new_asoc); 1609 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 1610 } 1611 1612 if (sctp_assoc_set_bind_addr_from_ep(new_asoc, 1613 sctp_scope(sctp_source(chunk)), GFP_ATOMIC) < 0) 1614 goto nomem; 1615 1616 /* In the outbound INIT ACK the endpoint MUST copy its current 1617 * Verification Tag and Peers Verification tag into a reserved 1618 * place (local tie-tag and per tie-tag) within the state cookie. 1619 */ 1620 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), 1621 (struct sctp_init_chunk *)chunk->chunk_hdr, 1622 GFP_ATOMIC)) 1623 goto nomem; 1624 1625 /* Make sure no new addresses are being added during the 1626 * restart. Do not do this check for COOKIE-WAIT state, 1627 * since there are no peer addresses to check against. 1628 * Upon return an ABORT will have been sent if needed. 1629 */ 1630 if (!sctp_state(asoc, COOKIE_WAIT)) { 1631 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, 1632 commands)) { 1633 retval = SCTP_DISPOSITION_CONSUME; 1634 goto nomem_retval; 1635 } 1636 } 1637 1638 sctp_tietags_populate(new_asoc, asoc); 1639 1640 /* B) "Z" shall respond immediately with an INIT ACK chunk. */ 1641 1642 /* If there are errors need to be reported for unknown parameters, 1643 * make sure to reserve enough room in the INIT ACK for them. 1644 */ 1645 len = 0; 1646 if (err_chunk) { 1647 len = ntohs(err_chunk->chunk_hdr->length) - 1648 sizeof(struct sctp_chunkhdr); 1649 } 1650 1651 repl = sctp_make_init_ack(new_asoc, chunk, GFP_ATOMIC, len); 1652 if (!repl) 1653 goto nomem; 1654 1655 /* If there are errors need to be reported for unknown parameters, 1656 * include them in the outgoing INIT ACK as "Unrecognized parameter" 1657 * parameter. 1658 */ 1659 if (err_chunk) { 1660 /* Get the "Unrecognized parameter" parameter(s) out of the 1661 * ERROR chunk generated by sctp_verify_init(). Since the 1662 * error cause code for "unknown parameter" and the 1663 * "Unrecognized parameter" type is the same, we can 1664 * construct the parameters in INIT ACK by copying the 1665 * ERROR causes over. 1666 */ 1667 unk_param = (struct sctp_unrecognized_param *) 1668 ((__u8 *)(err_chunk->chunk_hdr) + 1669 sizeof(struct sctp_chunkhdr)); 1670 /* Replace the cause code with the "Unrecognized parameter" 1671 * parameter type. 1672 */ 1673 sctp_addto_chunk(repl, len, unk_param); 1674 } 1675 1676 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(new_asoc)); 1677 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1678 1679 /* 1680 * Note: After sending out INIT ACK with the State Cookie parameter, 1681 * "Z" MUST NOT allocate any resources for this new association. 1682 * Otherwise, "Z" will be vulnerable to resource attacks. 1683 */ 1684 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 1685 retval = SCTP_DISPOSITION_CONSUME; 1686 1687 return retval; 1688 1689 nomem: 1690 retval = SCTP_DISPOSITION_NOMEM; 1691 nomem_retval: 1692 if (new_asoc) 1693 sctp_association_free(new_asoc); 1694 cleanup: 1695 if (err_chunk) 1696 sctp_chunk_free(err_chunk); 1697 return retval; 1698 } 1699 1700 /* 1701 * Handle simultaneous INIT. 1702 * This means we started an INIT and then we got an INIT request from 1703 * our peer. 1704 * 1705 * Section: 5.2.1 INIT received in COOKIE-WAIT or COOKIE-ECHOED State (Item B) 1706 * This usually indicates an initialization collision, i.e., each 1707 * endpoint is attempting, at about the same time, to establish an 1708 * association with the other endpoint. 1709 * 1710 * Upon receipt of an INIT in the COOKIE-WAIT or COOKIE-ECHOED state, an 1711 * endpoint MUST respond with an INIT ACK using the same parameters it 1712 * sent in its original INIT chunk (including its Verification Tag, 1713 * unchanged). These original parameters are combined with those from the 1714 * newly received INIT chunk. The endpoint shall also generate a State 1715 * Cookie with the INIT ACK. The endpoint uses the parameters sent in its 1716 * INIT to calculate the State Cookie. 1717 * 1718 * After that, the endpoint MUST NOT change its state, the T1-init 1719 * timer shall be left running and the corresponding TCB MUST NOT be 1720 * destroyed. The normal procedures for handling State Cookies when 1721 * a TCB exists will resolve the duplicate INITs to a single association. 1722 * 1723 * For an endpoint that is in the COOKIE-ECHOED state it MUST populate 1724 * its Tie-Tags with the Tag information of itself and its peer (see 1725 * section 5.2.2 for a description of the Tie-Tags). 1726 * 1727 * Verification Tag: Not explicit, but an INIT can not have a valid 1728 * verification tag, so we skip the check. 1729 * 1730 * Inputs 1731 * (endpoint, asoc, chunk) 1732 * 1733 * Outputs 1734 * (asoc, reply_msg, msg_up, timers, counters) 1735 * 1736 * The return value is the disposition of the chunk. 1737 */ 1738 enum sctp_disposition sctp_sf_do_5_2_1_siminit( 1739 struct net *net, 1740 const struct sctp_endpoint *ep, 1741 const struct sctp_association *asoc, 1742 const union sctp_subtype type, 1743 void *arg, 1744 struct sctp_cmd_seq *commands) 1745 { 1746 /* Call helper to do the real work for both simultaneous and 1747 * duplicate INIT chunk handling. 1748 */ 1749 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1750 } 1751 1752 /* 1753 * Handle duplicated INIT messages. These are usually delayed 1754 * restransmissions. 1755 * 1756 * Section: 5.2.2 Unexpected INIT in States Other than CLOSED, 1757 * COOKIE-ECHOED and COOKIE-WAIT 1758 * 1759 * Unless otherwise stated, upon reception of an unexpected INIT for 1760 * this association, the endpoint shall generate an INIT ACK with a 1761 * State Cookie. In the outbound INIT ACK the endpoint MUST copy its 1762 * current Verification Tag and peer's Verification Tag into a reserved 1763 * place within the state cookie. We shall refer to these locations as 1764 * the Peer's-Tie-Tag and the Local-Tie-Tag. The outbound SCTP packet 1765 * containing this INIT ACK MUST carry a Verification Tag value equal to 1766 * the Initiation Tag found in the unexpected INIT. And the INIT ACK 1767 * MUST contain a new Initiation Tag (randomly generated see Section 1768 * 5.3.1). Other parameters for the endpoint SHOULD be copied from the 1769 * existing parameters of the association (e.g. number of outbound 1770 * streams) into the INIT ACK and cookie. 1771 * 1772 * After sending out the INIT ACK, the endpoint shall take no further 1773 * actions, i.e., the existing association, including its current state, 1774 * and the corresponding TCB MUST NOT be changed. 1775 * 1776 * Note: Only when a TCB exists and the association is not in a COOKIE- 1777 * WAIT state are the Tie-Tags populated. For a normal association INIT 1778 * (i.e. the endpoint is in a COOKIE-WAIT state), the Tie-Tags MUST be 1779 * set to 0 (indicating that no previous TCB existed). The INIT ACK and 1780 * State Cookie are populated as specified in section 5.2.1. 1781 * 1782 * Verification Tag: Not specified, but an INIT has no way of knowing 1783 * what the verification tag could be, so we ignore it. 1784 * 1785 * Inputs 1786 * (endpoint, asoc, chunk) 1787 * 1788 * Outputs 1789 * (asoc, reply_msg, msg_up, timers, counters) 1790 * 1791 * The return value is the disposition of the chunk. 1792 */ 1793 enum sctp_disposition sctp_sf_do_5_2_2_dupinit( 1794 struct net *net, 1795 const struct sctp_endpoint *ep, 1796 const struct sctp_association *asoc, 1797 const union sctp_subtype type, 1798 void *arg, 1799 struct sctp_cmd_seq *commands) 1800 { 1801 /* Call helper to do the real work for both simultaneous and 1802 * duplicate INIT chunk handling. 1803 */ 1804 return sctp_sf_do_unexpected_init(net, ep, asoc, type, arg, commands); 1805 } 1806 1807 1808 /* 1809 * Unexpected INIT-ACK handler. 1810 * 1811 * Section 5.2.3 1812 * If an INIT ACK received by an endpoint in any state other than the 1813 * COOKIE-WAIT state, the endpoint should discard the INIT ACK chunk. 1814 * An unexpected INIT ACK usually indicates the processing of an old or 1815 * duplicated INIT chunk. 1816 */ 1817 enum sctp_disposition sctp_sf_do_5_2_3_initack( 1818 struct net *net, 1819 const struct sctp_endpoint *ep, 1820 const struct sctp_association *asoc, 1821 const union sctp_subtype type, 1822 void *arg, 1823 struct sctp_cmd_seq *commands) 1824 { 1825 /* Per the above section, we'll discard the chunk if we have an 1826 * endpoint. If this is an OOTB INIT-ACK, treat it as such. 1827 */ 1828 if (ep == sctp_sk(net->sctp.ctl_sock)->ep) 1829 return sctp_sf_ootb(net, ep, asoc, type, arg, commands); 1830 else 1831 return sctp_sf_discard_chunk(net, ep, asoc, type, arg, commands); 1832 } 1833 1834 static int sctp_sf_do_assoc_update(struct sctp_association *asoc, 1835 struct sctp_association *new, 1836 struct sctp_cmd_seq *cmds) 1837 { 1838 struct net *net = asoc->base.net; 1839 struct sctp_chunk *abort; 1840 1841 if (!sctp_assoc_update(asoc, new)) 1842 return 0; 1843 1844 abort = sctp_make_abort(asoc, NULL, sizeof(struct sctp_errhdr)); 1845 if (abort) { 1846 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 1847 sctp_add_cmd_sf(cmds, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 1848 } 1849 sctp_add_cmd_sf(cmds, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNABORTED)); 1850 sctp_add_cmd_sf(cmds, SCTP_CMD_ASSOC_FAILED, 1851 SCTP_PERR(SCTP_ERROR_RSRC_LOW)); 1852 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 1853 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 1854 1855 return -ENOMEM; 1856 } 1857 1858 /* Unexpected COOKIE-ECHO handler for peer restart (Table 2, action 'A') 1859 * 1860 * Section 5.2.4 1861 * A) In this case, the peer may have restarted. 1862 */ 1863 static enum sctp_disposition sctp_sf_do_dupcook_a( 1864 struct net *net, 1865 const struct sctp_endpoint *ep, 1866 const struct sctp_association *asoc, 1867 struct sctp_chunk *chunk, 1868 struct sctp_cmd_seq *commands, 1869 struct sctp_association *new_asoc) 1870 { 1871 struct sctp_init_chunk *peer_init; 1872 enum sctp_disposition disposition; 1873 struct sctp_ulpevent *ev; 1874 struct sctp_chunk *repl; 1875 struct sctp_chunk *err; 1876 1877 /* new_asoc is a brand-new association, so these are not yet 1878 * side effects--it is safe to run them here. 1879 */ 1880 peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1); 1881 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 1882 GFP_ATOMIC)) 1883 goto nomem; 1884 1885 if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC)) 1886 goto nomem; 1887 1888 if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) 1889 return SCTP_DISPOSITION_DISCARD; 1890 1891 /* Make sure no new addresses are being added during the 1892 * restart. Though this is a pretty complicated attack 1893 * since you'd have to get inside the cookie. 1894 */ 1895 if (!sctp_sf_check_restart_addrs(new_asoc, asoc, chunk, commands)) 1896 return SCTP_DISPOSITION_CONSUME; 1897 1898 /* If the endpoint is in the SHUTDOWN-ACK-SENT state and recognizes 1899 * the peer has restarted (Action A), it MUST NOT setup a new 1900 * association but instead resend the SHUTDOWN ACK and send an ERROR 1901 * chunk with a "Cookie Received while Shutting Down" error cause to 1902 * its peer. 1903 */ 1904 if (sctp_state(asoc, SHUTDOWN_ACK_SENT)) { 1905 disposition = __sctp_sf_do_9_2_reshutack(net, ep, asoc, 1906 SCTP_ST_CHUNK(chunk->chunk_hdr->type), 1907 chunk, commands); 1908 if (SCTP_DISPOSITION_NOMEM == disposition) 1909 goto nomem; 1910 1911 err = sctp_make_op_error(asoc, chunk, 1912 SCTP_ERROR_COOKIE_IN_SHUTDOWN, 1913 NULL, 0, 0); 1914 if (err) 1915 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 1916 SCTP_CHUNK(err)); 1917 1918 return SCTP_DISPOSITION_CONSUME; 1919 } 1920 1921 /* For now, stop pending T3-rtx and SACK timers, fail any unsent/unacked 1922 * data. Consider the optional choice of resending of this data. 1923 */ 1924 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 1925 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1926 SCTP_TO(SCTP_EVENT_TIMEOUT_SACK)); 1927 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 1928 1929 /* Stop pending T4-rto timer, teardown ASCONF queue, ASCONF-ACK queue 1930 * and ASCONF-ACK cache. 1931 */ 1932 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 1933 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 1934 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_ASCONF_QUEUE, SCTP_NULL()); 1935 1936 /* Update the content of current association. */ 1937 if (sctp_sf_do_assoc_update((struct sctp_association *)asoc, new_asoc, commands)) 1938 goto nomem; 1939 1940 repl = sctp_make_cookie_ack(asoc, chunk); 1941 if (!repl) 1942 goto nomem; 1943 1944 /* Report association restart to upper layer. */ 1945 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_RESTART, 0, 1946 asoc->c.sinit_num_ostreams, 1947 asoc->c.sinit_max_instreams, 1948 NULL, GFP_ATOMIC); 1949 if (!ev) 1950 goto nomem_ev; 1951 1952 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 1953 if ((sctp_state(asoc, SHUTDOWN_PENDING) || 1954 sctp_state(asoc, SHUTDOWN_SENT)) && 1955 (sctp_sstate(asoc->base.sk, CLOSING) || 1956 sock_flag(asoc->base.sk, SOCK_DEAD))) { 1957 /* If the socket has been closed by user, don't 1958 * transition to ESTABLISHED. Instead trigger SHUTDOWN 1959 * bundled with COOKIE_ACK. 1960 */ 1961 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1962 return sctp_sf_do_9_2_start_shutdown(net, ep, asoc, 1963 SCTP_ST_CHUNK(0), repl, 1964 commands); 1965 } else { 1966 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 1967 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 1968 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 1969 } 1970 return SCTP_DISPOSITION_CONSUME; 1971 1972 nomem_ev: 1973 sctp_chunk_free(repl); 1974 nomem: 1975 return SCTP_DISPOSITION_NOMEM; 1976 } 1977 1978 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'B') 1979 * 1980 * Section 5.2.4 1981 * B) In this case, both sides may be attempting to start an association 1982 * at about the same time but the peer endpoint started its INIT 1983 * after responding to the local endpoint's INIT 1984 */ 1985 /* This case represents an initialization collision. */ 1986 static enum sctp_disposition sctp_sf_do_dupcook_b( 1987 struct net *net, 1988 const struct sctp_endpoint *ep, 1989 const struct sctp_association *asoc, 1990 struct sctp_chunk *chunk, 1991 struct sctp_cmd_seq *commands, 1992 struct sctp_association *new_asoc) 1993 { 1994 struct sctp_init_chunk *peer_init; 1995 struct sctp_chunk *repl; 1996 1997 /* new_asoc is a brand-new association, so these are not yet 1998 * side effects--it is safe to run them here. 1999 */ 2000 peer_init = (struct sctp_init_chunk *)(chunk->subh.cookie_hdr + 1); 2001 if (!sctp_process_init(new_asoc, chunk, sctp_source(chunk), peer_init, 2002 GFP_ATOMIC)) 2003 goto nomem; 2004 2005 if (sctp_auth_asoc_init_active_key(new_asoc, GFP_ATOMIC)) 2006 goto nomem; 2007 2008 if (!sctp_auth_chunk_verify(net, chunk, new_asoc)) 2009 return SCTP_DISPOSITION_DISCARD; 2010 2011 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2012 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 2013 if (asoc->state < SCTP_STATE_ESTABLISHED) 2014 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 2015 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, SCTP_NULL()); 2016 2017 /* Update the content of current association. */ 2018 if (sctp_sf_do_assoc_update((struct sctp_association *)asoc, new_asoc, commands)) 2019 goto nomem; 2020 2021 repl = sctp_make_cookie_ack(asoc, chunk); 2022 if (!repl) 2023 goto nomem; 2024 2025 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 2026 2027 /* RFC 2960 5.1 Normal Establishment of an Association 2028 * 2029 * D) IMPLEMENTATION NOTE: An implementation may choose to 2030 * send the Communication Up notification to the SCTP user 2031 * upon reception of a valid COOKIE ECHO chunk. 2032 * 2033 * Sadly, this needs to be implemented as a side-effect, because 2034 * we are not guaranteed to have set the association id of the real 2035 * association and so these notifications need to be delayed until 2036 * the association id is allocated. 2037 */ 2038 2039 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_CHANGE, SCTP_U8(SCTP_COMM_UP)); 2040 2041 /* Sockets API Draft Section 5.3.1.6 2042 * When a peer sends a Adaptation Layer Indication parameter , SCTP 2043 * delivers this notification to inform the application that of the 2044 * peers requested adaptation layer. 2045 * 2046 * This also needs to be done as a side effect for the same reason as 2047 * above. 2048 */ 2049 if (asoc->peer.adaptation_ind) 2050 sctp_add_cmd_sf(commands, SCTP_CMD_ADAPTATION_IND, SCTP_NULL()); 2051 2052 if (!asoc->peer.auth_capable) 2053 sctp_add_cmd_sf(commands, SCTP_CMD_PEER_NO_AUTH, SCTP_NULL()); 2054 2055 return SCTP_DISPOSITION_CONSUME; 2056 2057 nomem: 2058 return SCTP_DISPOSITION_NOMEM; 2059 } 2060 2061 /* Unexpected COOKIE-ECHO handler for setup collision (Table 2, action 'C') 2062 * 2063 * Section 5.2.4 2064 * C) In this case, the local endpoint's cookie has arrived late. 2065 * Before it arrived, the local endpoint sent an INIT and received an 2066 * INIT-ACK and finally sent a COOKIE ECHO with the peer's same tag 2067 * but a new tag of its own. 2068 */ 2069 /* This case represents an initialization collision. */ 2070 static enum sctp_disposition sctp_sf_do_dupcook_c( 2071 struct net *net, 2072 const struct sctp_endpoint *ep, 2073 const struct sctp_association *asoc, 2074 struct sctp_chunk *chunk, 2075 struct sctp_cmd_seq *commands, 2076 struct sctp_association *new_asoc) 2077 { 2078 /* The cookie should be silently discarded. 2079 * The endpoint SHOULD NOT change states and should leave 2080 * any timers running. 2081 */ 2082 return SCTP_DISPOSITION_DISCARD; 2083 } 2084 2085 /* Unexpected COOKIE-ECHO handler lost chunk (Table 2, action 'D') 2086 * 2087 * Section 5.2.4 2088 * 2089 * D) When both local and remote tags match the endpoint should always 2090 * enter the ESTABLISHED state, if it has not already done so. 2091 */ 2092 /* This case represents an initialization collision. */ 2093 static enum sctp_disposition sctp_sf_do_dupcook_d( 2094 struct net *net, 2095 const struct sctp_endpoint *ep, 2096 const struct sctp_association *asoc, 2097 struct sctp_chunk *chunk, 2098 struct sctp_cmd_seq *commands, 2099 struct sctp_association *new_asoc) 2100 { 2101 struct sctp_ulpevent *ev = NULL, *ai_ev = NULL, *auth_ev = NULL; 2102 struct sctp_chunk *repl; 2103 2104 /* Clarification from Implementor's Guide: 2105 * D) When both local and remote tags match the endpoint should 2106 * enter the ESTABLISHED state, if it is in the COOKIE-ECHOED state. 2107 * It should stop any cookie timer that may be running and send 2108 * a COOKIE ACK. 2109 */ 2110 2111 if (!sctp_auth_chunk_verify(net, chunk, asoc)) 2112 return SCTP_DISPOSITION_DISCARD; 2113 2114 /* Don't accidentally move back into established state. */ 2115 if (asoc->state < SCTP_STATE_ESTABLISHED) { 2116 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2117 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2118 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2119 SCTP_STATE(SCTP_STATE_ESTABLISHED)); 2120 SCTP_INC_STATS(net, SCTP_MIB_CURRESTAB); 2121 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_START, 2122 SCTP_NULL()); 2123 2124 /* RFC 2960 5.1 Normal Establishment of an Association 2125 * 2126 * D) IMPLEMENTATION NOTE: An implementation may choose 2127 * to send the Communication Up notification to the 2128 * SCTP user upon reception of a valid COOKIE 2129 * ECHO chunk. 2130 */ 2131 ev = sctp_ulpevent_make_assoc_change(asoc, 0, 2132 SCTP_COMM_UP, 0, 2133 asoc->c.sinit_num_ostreams, 2134 asoc->c.sinit_max_instreams, 2135 NULL, GFP_ATOMIC); 2136 if (!ev) 2137 goto nomem; 2138 2139 /* Sockets API Draft Section 5.3.1.6 2140 * When a peer sends a Adaptation Layer Indication parameter, 2141 * SCTP delivers this notification to inform the application 2142 * that of the peers requested adaptation layer. 2143 */ 2144 if (asoc->peer.adaptation_ind) { 2145 ai_ev = sctp_ulpevent_make_adaptation_indication(asoc, 2146 GFP_ATOMIC); 2147 if (!ai_ev) 2148 goto nomem; 2149 2150 } 2151 2152 if (!asoc->peer.auth_capable) { 2153 auth_ev = sctp_ulpevent_make_authkey(asoc, 0, 2154 SCTP_AUTH_NO_AUTH, 2155 GFP_ATOMIC); 2156 if (!auth_ev) 2157 goto nomem; 2158 } 2159 } 2160 2161 repl = sctp_make_cookie_ack(asoc, chunk); 2162 if (!repl) 2163 goto nomem; 2164 2165 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 2166 2167 if (ev) 2168 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2169 SCTP_ULPEVENT(ev)); 2170 if (ai_ev) 2171 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2172 SCTP_ULPEVENT(ai_ev)); 2173 if (auth_ev) 2174 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 2175 SCTP_ULPEVENT(auth_ev)); 2176 2177 return SCTP_DISPOSITION_CONSUME; 2178 2179 nomem: 2180 if (auth_ev) 2181 sctp_ulpevent_free(auth_ev); 2182 if (ai_ev) 2183 sctp_ulpevent_free(ai_ev); 2184 if (ev) 2185 sctp_ulpevent_free(ev); 2186 return SCTP_DISPOSITION_NOMEM; 2187 } 2188 2189 /* 2190 * Handle a duplicate COOKIE-ECHO. This usually means a cookie-carrying 2191 * chunk was retransmitted and then delayed in the network. 2192 * 2193 * Section: 5.2.4 Handle a COOKIE ECHO when a TCB exists 2194 * 2195 * Verification Tag: None. Do cookie validation. 2196 * 2197 * Inputs 2198 * (endpoint, asoc, chunk) 2199 * 2200 * Outputs 2201 * (asoc, reply_msg, msg_up, timers, counters) 2202 * 2203 * The return value is the disposition of the chunk. 2204 */ 2205 enum sctp_disposition sctp_sf_do_5_2_4_dupcook( 2206 struct net *net, 2207 const struct sctp_endpoint *ep, 2208 const struct sctp_association *asoc, 2209 const union sctp_subtype type, 2210 void *arg, 2211 struct sctp_cmd_seq *commands) 2212 { 2213 struct sctp_association *new_asoc; 2214 struct sctp_chunk *chunk = arg; 2215 enum sctp_disposition retval; 2216 struct sctp_chunk *err_chk_p; 2217 int error = 0; 2218 char action; 2219 2220 /* Make sure that the chunk has a valid length from the protocol 2221 * perspective. In this case check to make sure we have at least 2222 * enough for the chunk header. Cookie length verification is 2223 * done later. 2224 */ 2225 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) { 2226 if (!sctp_vtag_verify(chunk, asoc)) 2227 asoc = NULL; 2228 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, commands); 2229 } 2230 2231 /* "Decode" the chunk. We have no optional parameters so we 2232 * are in good shape. 2233 */ 2234 chunk->subh.cookie_hdr = (struct sctp_signed_cookie *)chunk->skb->data; 2235 if (!pskb_pull(chunk->skb, ntohs(chunk->chunk_hdr->length) - 2236 sizeof(struct sctp_chunkhdr))) 2237 goto nomem; 2238 2239 /* In RFC 2960 5.2.4 3, if both Verification Tags in the State Cookie 2240 * of a duplicate COOKIE ECHO match the Verification Tags of the 2241 * current association, consider the State Cookie valid even if 2242 * the lifespan is exceeded. 2243 */ 2244 new_asoc = sctp_unpack_cookie(ep, asoc, chunk, GFP_ATOMIC, &error, 2245 &err_chk_p); 2246 2247 /* FIXME: 2248 * If the re-build failed, what is the proper error path 2249 * from here? 2250 * 2251 * [We should abort the association. --piggy] 2252 */ 2253 if (!new_asoc) { 2254 /* FIXME: Several errors are possible. A bad cookie should 2255 * be silently discarded, but think about logging it too. 2256 */ 2257 switch (error) { 2258 case -SCTP_IERROR_NOMEM: 2259 goto nomem; 2260 2261 case -SCTP_IERROR_STALE_COOKIE: 2262 sctp_send_stale_cookie_err(net, ep, asoc, chunk, commands, 2263 err_chk_p); 2264 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2265 case -SCTP_IERROR_BAD_SIG: 2266 default: 2267 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2268 } 2269 } 2270 2271 /* Set temp so that it won't be added into hashtable */ 2272 new_asoc->temp = 1; 2273 2274 /* Compare the tie_tag in cookie with the verification tag of 2275 * current association. 2276 */ 2277 action = sctp_tietags_compare(new_asoc, asoc); 2278 2279 /* In cases C and E the association doesn't enter the ESTABLISHED 2280 * state, so there is no need to call security_sctp_assoc_request(). 2281 */ 2282 switch (action) { 2283 case 'A': /* Association restart. */ 2284 case 'B': /* Collision case B. */ 2285 case 'D': /* Collision case D. */ 2286 /* Update socket peer label if first association. */ 2287 if (security_sctp_assoc_request((struct sctp_association *)asoc, 2288 chunk->head_skb ?: chunk->skb)) { 2289 sctp_association_free(new_asoc); 2290 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2291 } 2292 break; 2293 } 2294 2295 switch (action) { 2296 case 'A': /* Association restart. */ 2297 retval = sctp_sf_do_dupcook_a(net, ep, asoc, chunk, commands, 2298 new_asoc); 2299 break; 2300 2301 case 'B': /* Collision case B. */ 2302 retval = sctp_sf_do_dupcook_b(net, ep, asoc, chunk, commands, 2303 new_asoc); 2304 break; 2305 2306 case 'C': /* Collision case C. */ 2307 retval = sctp_sf_do_dupcook_c(net, ep, asoc, chunk, commands, 2308 new_asoc); 2309 break; 2310 2311 case 'D': /* Collision case D. */ 2312 retval = sctp_sf_do_dupcook_d(net, ep, asoc, chunk, commands, 2313 new_asoc); 2314 break; 2315 2316 default: /* Discard packet for all others. */ 2317 retval = sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2318 break; 2319 } 2320 2321 /* Delete the temporary new association. */ 2322 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, SCTP_ASOC(new_asoc)); 2323 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 2324 2325 /* Restore association pointer to provide SCTP command interpreter 2326 * with a valid context in case it needs to manipulate 2327 * the queues */ 2328 sctp_add_cmd_sf(commands, SCTP_CMD_SET_ASOC, 2329 SCTP_ASOC((struct sctp_association *)asoc)); 2330 2331 return retval; 2332 2333 nomem: 2334 return SCTP_DISPOSITION_NOMEM; 2335 } 2336 2337 /* 2338 * Process an ABORT. (SHUTDOWN-PENDING state) 2339 * 2340 * See sctp_sf_do_9_1_abort(). 2341 */ 2342 enum sctp_disposition sctp_sf_shutdown_pending_abort( 2343 struct net *net, 2344 const struct sctp_endpoint *ep, 2345 const struct sctp_association *asoc, 2346 const union sctp_subtype type, 2347 void *arg, 2348 struct sctp_cmd_seq *commands) 2349 { 2350 struct sctp_chunk *chunk = arg; 2351 2352 if (!sctp_vtag_verify_either(chunk, asoc)) 2353 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2354 2355 /* Make sure that the ABORT chunk has a valid length. 2356 * Since this is an ABORT chunk, we have to discard it 2357 * because of the following text: 2358 * RFC 2960, Section 3.3.7 2359 * If an endpoint receives an ABORT with a format error or for an 2360 * association that doesn't exist, it MUST silently discard it. 2361 * Because the length is "invalid", we can't really discard just 2362 * as we do not know its true length. So, to be safe, discard the 2363 * packet. 2364 */ 2365 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2366 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2367 2368 /* ADD-IP: Special case for ABORT chunks 2369 * F4) One special consideration is that ABORT Chunks arriving 2370 * destined to the IP address being deleted MUST be 2371 * ignored (see Section 5.3.1 for further details). 2372 */ 2373 if (SCTP_ADDR_DEL == 2374 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2375 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2376 2377 if (!sctp_err_chunk_valid(chunk)) 2378 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2379 2380 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2381 } 2382 2383 /* 2384 * Process an ABORT. (SHUTDOWN-SENT state) 2385 * 2386 * See sctp_sf_do_9_1_abort(). 2387 */ 2388 enum sctp_disposition sctp_sf_shutdown_sent_abort( 2389 struct net *net, 2390 const struct sctp_endpoint *ep, 2391 const struct sctp_association *asoc, 2392 const union sctp_subtype type, 2393 void *arg, 2394 struct sctp_cmd_seq *commands) 2395 { 2396 struct sctp_chunk *chunk = arg; 2397 2398 if (!sctp_vtag_verify_either(chunk, asoc)) 2399 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2400 2401 /* Make sure that the ABORT chunk has a valid length. 2402 * Since this is an ABORT chunk, we have to discard it 2403 * because of the following text: 2404 * RFC 2960, Section 3.3.7 2405 * If an endpoint receives an ABORT with a format error or for an 2406 * association that doesn't exist, it MUST silently discard it. 2407 * Because the length is "invalid", we can't really discard just 2408 * as we do not know its true length. So, to be safe, discard the 2409 * packet. 2410 */ 2411 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2412 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2413 2414 /* ADD-IP: Special case for ABORT chunks 2415 * F4) One special consideration is that ABORT Chunks arriving 2416 * destined to the IP address being deleted MUST be 2417 * ignored (see Section 5.3.1 for further details). 2418 */ 2419 if (SCTP_ADDR_DEL == 2420 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2421 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2422 2423 if (!sctp_err_chunk_valid(chunk)) 2424 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2425 2426 /* Stop the T2-shutdown timer. */ 2427 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2428 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 2429 2430 /* Stop the T5-shutdown guard timer. */ 2431 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2432 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 2433 2434 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2435 } 2436 2437 /* 2438 * Process an ABORT. (SHUTDOWN-ACK-SENT state) 2439 * 2440 * See sctp_sf_do_9_1_abort(). 2441 */ 2442 enum sctp_disposition sctp_sf_shutdown_ack_sent_abort( 2443 struct net *net, 2444 const struct sctp_endpoint *ep, 2445 const struct sctp_association *asoc, 2446 const union sctp_subtype type, 2447 void *arg, 2448 struct sctp_cmd_seq *commands) 2449 { 2450 /* The same T2 timer, so we should be able to use 2451 * common function with the SHUTDOWN-SENT state. 2452 */ 2453 return sctp_sf_shutdown_sent_abort(net, ep, asoc, type, arg, commands); 2454 } 2455 2456 /* 2457 * Handle an Error received in COOKIE_ECHOED state. 2458 * 2459 * Only handle the error type of stale COOKIE Error, the other errors will 2460 * be ignored. 2461 * 2462 * Inputs 2463 * (endpoint, asoc, chunk) 2464 * 2465 * Outputs 2466 * (asoc, reply_msg, msg_up, timers, counters) 2467 * 2468 * The return value is the disposition of the chunk. 2469 */ 2470 enum sctp_disposition sctp_sf_cookie_echoed_err( 2471 struct net *net, 2472 const struct sctp_endpoint *ep, 2473 const struct sctp_association *asoc, 2474 const union sctp_subtype type, 2475 void *arg, 2476 struct sctp_cmd_seq *commands) 2477 { 2478 struct sctp_chunk *chunk = arg; 2479 struct sctp_errhdr *err; 2480 2481 if (!sctp_vtag_verify(chunk, asoc)) 2482 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2483 2484 /* Make sure that the ERROR chunk has a valid length. 2485 * The parameter walking depends on this as well. 2486 */ 2487 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk))) 2488 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2489 commands); 2490 2491 /* Process the error here */ 2492 /* FUTURE FIXME: When PR-SCTP related and other optional 2493 * parms are emitted, this will have to change to handle multiple 2494 * errors. 2495 */ 2496 sctp_walk_errors(err, chunk->chunk_hdr) { 2497 if (SCTP_ERROR_STALE_COOKIE == err->cause) 2498 return sctp_sf_do_5_2_6_stale(net, ep, asoc, type, 2499 arg, commands); 2500 } 2501 2502 /* It is possible to have malformed error causes, and that 2503 * will cause us to end the walk early. However, since 2504 * we are discarding the packet, there should be no adverse 2505 * affects. 2506 */ 2507 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2508 } 2509 2510 /* 2511 * Handle a Stale COOKIE Error 2512 * 2513 * Section: 5.2.6 Handle Stale COOKIE Error 2514 * If the association is in the COOKIE-ECHOED state, the endpoint may elect 2515 * one of the following three alternatives. 2516 * ... 2517 * 3) Send a new INIT chunk to the endpoint, adding a Cookie 2518 * Preservative parameter requesting an extension to the lifetime of 2519 * the State Cookie. When calculating the time extension, an 2520 * implementation SHOULD use the RTT information measured based on the 2521 * previous COOKIE ECHO / ERROR exchange, and should add no more 2522 * than 1 second beyond the measured RTT, due to long State Cookie 2523 * lifetimes making the endpoint more subject to a replay attack. 2524 * 2525 * Verification Tag: Not explicit, but safe to ignore. 2526 * 2527 * Inputs 2528 * (endpoint, asoc, chunk) 2529 * 2530 * Outputs 2531 * (asoc, reply_msg, msg_up, timers, counters) 2532 * 2533 * The return value is the disposition of the chunk. 2534 */ 2535 static enum sctp_disposition sctp_sf_do_5_2_6_stale( 2536 struct net *net, 2537 const struct sctp_endpoint *ep, 2538 const struct sctp_association *asoc, 2539 const union sctp_subtype type, 2540 void *arg, 2541 struct sctp_cmd_seq *commands) 2542 { 2543 int attempts = asoc->init_err_counter + 1; 2544 struct sctp_chunk *chunk = arg, *reply; 2545 struct sctp_cookie_preserve_param bht; 2546 struct sctp_bind_addr *bp; 2547 struct sctp_errhdr *err; 2548 u32 stale; 2549 2550 if (attempts > asoc->max_init_attempts) { 2551 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 2552 SCTP_ERROR(ETIMEDOUT)); 2553 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2554 SCTP_PERR(SCTP_ERROR_STALE_COOKIE)); 2555 return SCTP_DISPOSITION_DELETE_TCB; 2556 } 2557 2558 err = (struct sctp_errhdr *)(chunk->skb->data); 2559 2560 /* When calculating the time extension, an implementation 2561 * SHOULD use the RTT information measured based on the 2562 * previous COOKIE ECHO / ERROR exchange, and should add no 2563 * more than 1 second beyond the measured RTT, due to long 2564 * State Cookie lifetimes making the endpoint more subject to 2565 * a replay attack. 2566 * Measure of Staleness's unit is usec. (1/1000000 sec) 2567 * Suggested Cookie Life-span Increment's unit is msec. 2568 * (1/1000 sec) 2569 * In general, if you use the suggested cookie life, the value 2570 * found in the field of measure of staleness should be doubled 2571 * to give ample time to retransmit the new cookie and thus 2572 * yield a higher probability of success on the reattempt. 2573 */ 2574 stale = ntohl(*(__be32 *)((u8 *)err + sizeof(*err))); 2575 stale = (stale * 2) / 1000; 2576 2577 bht.param_hdr.type = SCTP_PARAM_COOKIE_PRESERVATIVE; 2578 bht.param_hdr.length = htons(sizeof(bht)); 2579 bht.lifespan_increment = htonl(stale); 2580 2581 /* Build that new INIT chunk. */ 2582 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 2583 reply = sctp_make_init(asoc, bp, GFP_ATOMIC, sizeof(bht)); 2584 if (!reply) 2585 goto nomem; 2586 2587 sctp_addto_chunk(reply, sizeof(bht), &bht); 2588 2589 /* Clear peer's init_tag cached in assoc as we are sending a new INIT */ 2590 sctp_add_cmd_sf(commands, SCTP_CMD_CLEAR_INIT_TAG, SCTP_NULL()); 2591 2592 /* Stop pending T3-rtx and heartbeat timers */ 2593 sctp_add_cmd_sf(commands, SCTP_CMD_T3_RTX_TIMERS_STOP, SCTP_NULL()); 2594 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 2595 2596 /* Delete non-primary peer ip addresses since we are transitioning 2597 * back to the COOKIE-WAIT state 2598 */ 2599 sctp_add_cmd_sf(commands, SCTP_CMD_DEL_NON_PRIMARY, SCTP_NULL()); 2600 2601 sctp_add_cmd_sf(commands, SCTP_CMD_PURGE_OUTQUEUE, SCTP_NULL()); 2602 2603 /* Cast away the const modifier, as we want to just 2604 * rerun it through as a sideffect. 2605 */ 2606 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_COUNTER_INC, SCTP_NULL()); 2607 2608 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2609 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 2610 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2611 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 2612 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 2613 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2614 2615 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 2616 2617 return SCTP_DISPOSITION_CONSUME; 2618 2619 nomem: 2620 return SCTP_DISPOSITION_NOMEM; 2621 } 2622 2623 /* 2624 * Process an ABORT. 2625 * 2626 * Section: 9.1 2627 * After checking the Verification Tag, the receiving endpoint shall 2628 * remove the association from its record, and shall report the 2629 * termination to its upper layer. 2630 * 2631 * Verification Tag: 8.5.1 Exceptions in Verification Tag Rules 2632 * B) Rules for packet carrying ABORT: 2633 * 2634 * - The endpoint shall always fill in the Verification Tag field of the 2635 * outbound packet with the destination endpoint's tag value if it 2636 * is known. 2637 * 2638 * - If the ABORT is sent in response to an OOTB packet, the endpoint 2639 * MUST follow the procedure described in Section 8.4. 2640 * 2641 * - The receiver MUST accept the packet if the Verification Tag 2642 * matches either its own tag, OR the tag of its peer. Otherwise, the 2643 * receiver MUST silently discard the packet and take no further 2644 * action. 2645 * 2646 * Inputs 2647 * (endpoint, asoc, chunk) 2648 * 2649 * Outputs 2650 * (asoc, reply_msg, msg_up, timers, counters) 2651 * 2652 * The return value is the disposition of the chunk. 2653 */ 2654 enum sctp_disposition sctp_sf_do_9_1_abort( 2655 struct net *net, 2656 const struct sctp_endpoint *ep, 2657 const struct sctp_association *asoc, 2658 const union sctp_subtype type, 2659 void *arg, 2660 struct sctp_cmd_seq *commands) 2661 { 2662 struct sctp_chunk *chunk = arg; 2663 2664 if (!sctp_vtag_verify_either(chunk, asoc)) 2665 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2666 2667 /* Make sure that the ABORT chunk has a valid length. 2668 * Since this is an ABORT chunk, we have to discard it 2669 * because of the following text: 2670 * RFC 2960, Section 3.3.7 2671 * If an endpoint receives an ABORT with a format error or for an 2672 * association that doesn't exist, it MUST silently discard it. 2673 * Because the length is "invalid", we can't really discard just 2674 * as we do not know its true length. So, to be safe, discard the 2675 * packet. 2676 */ 2677 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2678 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2679 2680 /* ADD-IP: Special case for ABORT chunks 2681 * F4) One special consideration is that ABORT Chunks arriving 2682 * destined to the IP address being deleted MUST be 2683 * ignored (see Section 5.3.1 for further details). 2684 */ 2685 if (SCTP_ADDR_DEL == 2686 sctp_bind_addr_state(&asoc->base.bind_addr, &chunk->dest)) 2687 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2688 2689 if (!sctp_err_chunk_valid(chunk)) 2690 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2691 2692 return __sctp_sf_do_9_1_abort(net, ep, asoc, type, arg, commands); 2693 } 2694 2695 static enum sctp_disposition __sctp_sf_do_9_1_abort( 2696 struct net *net, 2697 const struct sctp_endpoint *ep, 2698 const struct sctp_association *asoc, 2699 const union sctp_subtype type, 2700 void *arg, 2701 struct sctp_cmd_seq *commands) 2702 { 2703 __be16 error = SCTP_ERROR_NO_ERROR; 2704 struct sctp_chunk *chunk = arg; 2705 unsigned int len; 2706 2707 /* See if we have an error cause code in the chunk. */ 2708 len = ntohs(chunk->chunk_hdr->length); 2709 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2710 error = ((struct sctp_errhdr *)chunk->skb->data)->cause; 2711 2712 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(ECONNRESET)); 2713 /* ASSOC_FAILED will DELETE_TCB. */ 2714 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, SCTP_PERR(error)); 2715 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2716 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 2717 2718 return SCTP_DISPOSITION_ABORT; 2719 } 2720 2721 /* 2722 * Process an ABORT. (COOKIE-WAIT state) 2723 * 2724 * See sctp_sf_do_9_1_abort() above. 2725 */ 2726 enum sctp_disposition sctp_sf_cookie_wait_abort( 2727 struct net *net, 2728 const struct sctp_endpoint *ep, 2729 const struct sctp_association *asoc, 2730 const union sctp_subtype type, 2731 void *arg, 2732 struct sctp_cmd_seq *commands) 2733 { 2734 __be16 error = SCTP_ERROR_NO_ERROR; 2735 struct sctp_chunk *chunk = arg; 2736 unsigned int len; 2737 2738 if (!sctp_vtag_verify_either(chunk, asoc)) 2739 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2740 2741 /* Make sure that the ABORT chunk has a valid length. 2742 * Since this is an ABORT chunk, we have to discard it 2743 * because of the following text: 2744 * RFC 2960, Section 3.3.7 2745 * If an endpoint receives an ABORT with a format error or for an 2746 * association that doesn't exist, it MUST silently discard it. 2747 * Because the length is "invalid", we can't really discard just 2748 * as we do not know its true length. So, to be safe, discard the 2749 * packet. 2750 */ 2751 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_abort_chunk))) 2752 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2753 2754 /* See if we have an error cause code in the chunk. */ 2755 len = ntohs(chunk->chunk_hdr->length); 2756 if (len >= sizeof(struct sctp_chunkhdr) + sizeof(struct sctp_errhdr)) 2757 error = ((struct sctp_errhdr *)chunk->skb->data)->cause; 2758 2759 return sctp_stop_t1_and_abort(net, commands, error, ECONNREFUSED, asoc, 2760 chunk->transport); 2761 } 2762 2763 /* 2764 * Process an incoming ICMP as an ABORT. (COOKIE-WAIT state) 2765 */ 2766 enum sctp_disposition sctp_sf_cookie_wait_icmp_abort( 2767 struct net *net, 2768 const struct sctp_endpoint *ep, 2769 const struct sctp_association *asoc, 2770 const union sctp_subtype type, 2771 void *arg, 2772 struct sctp_cmd_seq *commands) 2773 { 2774 return sctp_stop_t1_and_abort(net, commands, SCTP_ERROR_NO_ERROR, 2775 ENOPROTOOPT, asoc, 2776 (struct sctp_transport *)arg); 2777 } 2778 2779 /* 2780 * Process an ABORT. (COOKIE-ECHOED state) 2781 */ 2782 enum sctp_disposition sctp_sf_cookie_echoed_abort( 2783 struct net *net, 2784 const struct sctp_endpoint *ep, 2785 const struct sctp_association *asoc, 2786 const union sctp_subtype type, 2787 void *arg, 2788 struct sctp_cmd_seq *commands) 2789 { 2790 /* There is a single T1 timer, so we should be able to use 2791 * common function with the COOKIE-WAIT state. 2792 */ 2793 return sctp_sf_cookie_wait_abort(net, ep, asoc, type, arg, commands); 2794 } 2795 2796 /* 2797 * Stop T1 timer and abort association with "INIT failed". 2798 * 2799 * This is common code called by several sctp_sf_*_abort() functions above. 2800 */ 2801 static enum sctp_disposition sctp_stop_t1_and_abort( 2802 struct net *net, 2803 struct sctp_cmd_seq *commands, 2804 __be16 error, int sk_err, 2805 const struct sctp_association *asoc, 2806 struct sctp_transport *transport) 2807 { 2808 pr_debug("%s: ABORT received (INIT)\n", __func__); 2809 2810 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2811 SCTP_STATE(SCTP_STATE_CLOSED)); 2812 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 2813 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 2814 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 2815 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, SCTP_ERROR(sk_err)); 2816 /* CMD_INIT_FAILED will DELETE_TCB. */ 2817 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 2818 SCTP_PERR(error)); 2819 2820 return SCTP_DISPOSITION_ABORT; 2821 } 2822 2823 /* 2824 * sctp_sf_do_9_2_shut 2825 * 2826 * Section: 9.2 2827 * Upon the reception of the SHUTDOWN, the peer endpoint shall 2828 * - enter the SHUTDOWN-RECEIVED state, 2829 * 2830 * - stop accepting new data from its SCTP user 2831 * 2832 * - verify, by checking the Cumulative TSN Ack field of the chunk, 2833 * that all its outstanding DATA chunks have been received by the 2834 * SHUTDOWN sender. 2835 * 2836 * Once an endpoint as reached the SHUTDOWN-RECEIVED state it MUST NOT 2837 * send a SHUTDOWN in response to a ULP request. And should discard 2838 * subsequent SHUTDOWN chunks. 2839 * 2840 * If there are still outstanding DATA chunks left, the SHUTDOWN 2841 * receiver shall continue to follow normal data transmission 2842 * procedures defined in Section 6 until all outstanding DATA chunks 2843 * are acknowledged; however, the SHUTDOWN receiver MUST NOT accept 2844 * new data from its SCTP user. 2845 * 2846 * Verification Tag: 8.5 Verification Tag [Normal verification] 2847 * 2848 * Inputs 2849 * (endpoint, asoc, chunk) 2850 * 2851 * Outputs 2852 * (asoc, reply_msg, msg_up, timers, counters) 2853 * 2854 * The return value is the disposition of the chunk. 2855 */ 2856 enum sctp_disposition sctp_sf_do_9_2_shutdown( 2857 struct net *net, 2858 const struct sctp_endpoint *ep, 2859 const struct sctp_association *asoc, 2860 const union sctp_subtype type, 2861 void *arg, 2862 struct sctp_cmd_seq *commands) 2863 { 2864 enum sctp_disposition disposition; 2865 struct sctp_chunk *chunk = arg; 2866 struct sctp_shutdownhdr *sdh; 2867 struct sctp_ulpevent *ev; 2868 __u32 ctsn; 2869 2870 if (!sctp_vtag_verify(chunk, asoc)) 2871 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2872 2873 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2874 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk))) 2875 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2876 commands); 2877 2878 /* Convert the elaborate header. */ 2879 sdh = (struct sctp_shutdownhdr *)chunk->skb->data; 2880 skb_pull(chunk->skb, sizeof(*sdh)); 2881 chunk->subh.shutdown_hdr = sdh; 2882 ctsn = ntohl(sdh->cum_tsn_ack); 2883 2884 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2885 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2886 asoc->ctsn_ack_point); 2887 2888 return SCTP_DISPOSITION_DISCARD; 2889 } 2890 2891 /* If Cumulative TSN Ack beyond the max tsn currently 2892 * send, terminating the association and respond to the 2893 * sender with an ABORT. 2894 */ 2895 if (!TSN_lt(ctsn, asoc->next_tsn)) 2896 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2897 2898 /* API 5.3.1.5 SCTP_SHUTDOWN_EVENT 2899 * When a peer sends a SHUTDOWN, SCTP delivers this notification to 2900 * inform the application that it should cease sending data. 2901 */ 2902 ev = sctp_ulpevent_make_shutdown_event(asoc, 0, GFP_ATOMIC); 2903 if (!ev) { 2904 disposition = SCTP_DISPOSITION_NOMEM; 2905 goto out; 2906 } 2907 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 2908 2909 /* Upon the reception of the SHUTDOWN, the peer endpoint shall 2910 * - enter the SHUTDOWN-RECEIVED state, 2911 * - stop accepting new data from its SCTP user 2912 * 2913 * [This is implicit in the new state.] 2914 */ 2915 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 2916 SCTP_STATE(SCTP_STATE_SHUTDOWN_RECEIVED)); 2917 disposition = SCTP_DISPOSITION_CONSUME; 2918 2919 if (sctp_outq_is_empty(&asoc->outqueue)) { 2920 disposition = sctp_sf_do_9_2_shutdown_ack(net, ep, asoc, type, 2921 arg, commands); 2922 } 2923 2924 if (SCTP_DISPOSITION_NOMEM == disposition) 2925 goto out; 2926 2927 /* - verify, by checking the Cumulative TSN Ack field of the 2928 * chunk, that all its outstanding DATA chunks have been 2929 * received by the SHUTDOWN sender. 2930 */ 2931 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2932 SCTP_BE32(chunk->subh.shutdown_hdr->cum_tsn_ack)); 2933 2934 out: 2935 return disposition; 2936 } 2937 2938 /* 2939 * sctp_sf_do_9_2_shut_ctsn 2940 * 2941 * Once an endpoint has reached the SHUTDOWN-RECEIVED state, 2942 * it MUST NOT send a SHUTDOWN in response to a ULP request. 2943 * The Cumulative TSN Ack of the received SHUTDOWN chunk 2944 * MUST be processed. 2945 */ 2946 enum sctp_disposition sctp_sf_do_9_2_shut_ctsn( 2947 struct net *net, 2948 const struct sctp_endpoint *ep, 2949 const struct sctp_association *asoc, 2950 const union sctp_subtype type, 2951 void *arg, 2952 struct sctp_cmd_seq *commands) 2953 { 2954 struct sctp_chunk *chunk = arg; 2955 struct sctp_shutdownhdr *sdh; 2956 __u32 ctsn; 2957 2958 if (!sctp_vtag_verify(chunk, asoc)) 2959 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 2960 2961 /* Make sure that the SHUTDOWN chunk has a valid length. */ 2962 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_shutdown_chunk))) 2963 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 2964 commands); 2965 2966 sdh = (struct sctp_shutdownhdr *)chunk->skb->data; 2967 ctsn = ntohl(sdh->cum_tsn_ack); 2968 2969 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 2970 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 2971 asoc->ctsn_ack_point); 2972 2973 return SCTP_DISPOSITION_DISCARD; 2974 } 2975 2976 /* If Cumulative TSN Ack beyond the max tsn currently 2977 * send, terminating the association and respond to the 2978 * sender with an ABORT. 2979 */ 2980 if (!TSN_lt(ctsn, asoc->next_tsn)) 2981 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 2982 2983 /* verify, by checking the Cumulative TSN Ack field of the 2984 * chunk, that all its outstanding DATA chunks have been 2985 * received by the SHUTDOWN sender. 2986 */ 2987 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_CTSN, 2988 SCTP_BE32(sdh->cum_tsn_ack)); 2989 2990 return SCTP_DISPOSITION_CONSUME; 2991 } 2992 2993 /* RFC 2960 9.2 2994 * If an endpoint is in SHUTDOWN-ACK-SENT state and receives an INIT chunk 2995 * (e.g., if the SHUTDOWN COMPLETE was lost) with source and destination 2996 * transport addresses (either in the IP addresses or in the INIT chunk) 2997 * that belong to this association, it should discard the INIT chunk and 2998 * retransmit the SHUTDOWN ACK chunk. 2999 */ 3000 static enum sctp_disposition 3001 __sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep, 3002 const struct sctp_association *asoc, 3003 const union sctp_subtype type, void *arg, 3004 struct sctp_cmd_seq *commands) 3005 { 3006 struct sctp_chunk *chunk = arg; 3007 struct sctp_chunk *reply; 3008 3009 /* Make sure that the chunk has a valid length */ 3010 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3011 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3012 commands); 3013 3014 /* Since we are not going to really process this INIT, there 3015 * is no point in verifying chunk boundaries. Just generate 3016 * the SHUTDOWN ACK. 3017 */ 3018 reply = sctp_make_shutdown_ack(asoc, chunk); 3019 if (NULL == reply) 3020 goto nomem; 3021 3022 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 3023 * the T2-SHUTDOWN timer. 3024 */ 3025 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 3026 3027 /* and restart the T2-shutdown timer. */ 3028 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3029 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3030 3031 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3032 3033 return SCTP_DISPOSITION_CONSUME; 3034 nomem: 3035 return SCTP_DISPOSITION_NOMEM; 3036 } 3037 3038 enum sctp_disposition 3039 sctp_sf_do_9_2_reshutack(struct net *net, const struct sctp_endpoint *ep, 3040 const struct sctp_association *asoc, 3041 const union sctp_subtype type, void *arg, 3042 struct sctp_cmd_seq *commands) 3043 { 3044 struct sctp_chunk *chunk = arg; 3045 3046 if (!chunk->singleton) 3047 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3048 3049 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_init_chunk))) 3050 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3051 3052 if (chunk->sctp_hdr->vtag != 0) 3053 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 3054 3055 return __sctp_sf_do_9_2_reshutack(net, ep, asoc, type, arg, commands); 3056 } 3057 3058 /* 3059 * sctp_sf_do_ecn_cwr 3060 * 3061 * Section: Appendix A: Explicit Congestion Notification 3062 * 3063 * CWR: 3064 * 3065 * RFC 2481 details a specific bit for a sender to send in the header of 3066 * its next outbound TCP segment to indicate to its peer that it has 3067 * reduced its congestion window. This is termed the CWR bit. For 3068 * SCTP the same indication is made by including the CWR chunk. 3069 * This chunk contains one data element, i.e. the TSN number that 3070 * was sent in the ECNE chunk. This element represents the lowest 3071 * TSN number in the datagram that was originally marked with the 3072 * CE bit. 3073 * 3074 * Verification Tag: 8.5 Verification Tag [Normal verification] 3075 * Inputs 3076 * (endpoint, asoc, chunk) 3077 * 3078 * Outputs 3079 * (asoc, reply_msg, msg_up, timers, counters) 3080 * 3081 * The return value is the disposition of the chunk. 3082 */ 3083 enum sctp_disposition sctp_sf_do_ecn_cwr(struct net *net, 3084 const struct sctp_endpoint *ep, 3085 const struct sctp_association *asoc, 3086 const union sctp_subtype type, 3087 void *arg, 3088 struct sctp_cmd_seq *commands) 3089 { 3090 struct sctp_chunk *chunk = arg; 3091 struct sctp_cwrhdr *cwr; 3092 u32 lowest_tsn; 3093 3094 if (!sctp_vtag_verify(chunk, asoc)) 3095 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3096 3097 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk))) 3098 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3099 commands); 3100 3101 cwr = (struct sctp_cwrhdr *)chunk->skb->data; 3102 skb_pull(chunk->skb, sizeof(*cwr)); 3103 3104 lowest_tsn = ntohl(cwr->lowest_tsn); 3105 3106 /* Does this CWR ack the last sent congestion notification? */ 3107 if (TSN_lte(asoc->last_ecne_tsn, lowest_tsn)) { 3108 /* Stop sending ECNE. */ 3109 sctp_add_cmd_sf(commands, 3110 SCTP_CMD_ECN_CWR, 3111 SCTP_U32(lowest_tsn)); 3112 } 3113 return SCTP_DISPOSITION_CONSUME; 3114 } 3115 3116 /* 3117 * sctp_sf_do_ecne 3118 * 3119 * Section: Appendix A: Explicit Congestion Notification 3120 * 3121 * ECN-Echo 3122 * 3123 * RFC 2481 details a specific bit for a receiver to send back in its 3124 * TCP acknowledgements to notify the sender of the Congestion 3125 * Experienced (CE) bit having arrived from the network. For SCTP this 3126 * same indication is made by including the ECNE chunk. This chunk 3127 * contains one data element, i.e. the lowest TSN associated with the IP 3128 * datagram marked with the CE bit..... 3129 * 3130 * Verification Tag: 8.5 Verification Tag [Normal verification] 3131 * Inputs 3132 * (endpoint, asoc, chunk) 3133 * 3134 * Outputs 3135 * (asoc, reply_msg, msg_up, timers, counters) 3136 * 3137 * The return value is the disposition of the chunk. 3138 */ 3139 enum sctp_disposition sctp_sf_do_ecne(struct net *net, 3140 const struct sctp_endpoint *ep, 3141 const struct sctp_association *asoc, 3142 const union sctp_subtype type, 3143 void *arg, struct sctp_cmd_seq *commands) 3144 { 3145 struct sctp_chunk *chunk = arg; 3146 struct sctp_ecnehdr *ecne; 3147 3148 if (!sctp_vtag_verify(chunk, asoc)) 3149 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3150 3151 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_ecne_chunk))) 3152 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3153 commands); 3154 3155 ecne = (struct sctp_ecnehdr *)chunk->skb->data; 3156 skb_pull(chunk->skb, sizeof(*ecne)); 3157 3158 /* If this is a newer ECNE than the last CWR packet we sent out */ 3159 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_ECNE, 3160 SCTP_U32(ntohl(ecne->lowest_tsn))); 3161 3162 return SCTP_DISPOSITION_CONSUME; 3163 } 3164 3165 /* 3166 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 3167 * 3168 * The SCTP endpoint MUST always acknowledge the reception of each valid 3169 * DATA chunk. 3170 * 3171 * The guidelines on delayed acknowledgement algorithm specified in 3172 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 3173 * acknowledgement SHOULD be generated for at least every second packet 3174 * (not every second DATA chunk) received, and SHOULD be generated within 3175 * 200 ms of the arrival of any unacknowledged DATA chunk. In some 3176 * situations it may be beneficial for an SCTP transmitter to be more 3177 * conservative than the algorithms detailed in this document allow. 3178 * However, an SCTP transmitter MUST NOT be more aggressive than the 3179 * following algorithms allow. 3180 * 3181 * A SCTP receiver MUST NOT generate more than one SACK for every 3182 * incoming packet, other than to update the offered window as the 3183 * receiving application consumes new data. 3184 * 3185 * Verification Tag: 8.5 Verification Tag [Normal verification] 3186 * 3187 * Inputs 3188 * (endpoint, asoc, chunk) 3189 * 3190 * Outputs 3191 * (asoc, reply_msg, msg_up, timers, counters) 3192 * 3193 * The return value is the disposition of the chunk. 3194 */ 3195 enum sctp_disposition sctp_sf_eat_data_6_2(struct net *net, 3196 const struct sctp_endpoint *ep, 3197 const struct sctp_association *asoc, 3198 const union sctp_subtype type, 3199 void *arg, 3200 struct sctp_cmd_seq *commands) 3201 { 3202 union sctp_arg force = SCTP_NOFORCE(); 3203 struct sctp_chunk *chunk = arg; 3204 int error; 3205 3206 if (!sctp_vtag_verify(chunk, asoc)) { 3207 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3208 SCTP_NULL()); 3209 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3210 } 3211 3212 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream))) 3213 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3214 commands); 3215 3216 error = sctp_eat_data(asoc, chunk, commands); 3217 switch (error) { 3218 case SCTP_IERROR_NO_ERROR: 3219 break; 3220 case SCTP_IERROR_HIGH_TSN: 3221 case SCTP_IERROR_BAD_STREAM: 3222 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3223 goto discard_noforce; 3224 case SCTP_IERROR_DUP_TSN: 3225 case SCTP_IERROR_IGNORE_TSN: 3226 SCTP_INC_STATS(net, SCTP_MIB_IN_DATA_CHUNK_DISCARDS); 3227 goto discard_force; 3228 case SCTP_IERROR_NO_DATA: 3229 return SCTP_DISPOSITION_ABORT; 3230 case SCTP_IERROR_PROTO_VIOLATION: 3231 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3232 (u8 *)chunk->subh.data_hdr, 3233 sctp_datahdr_len(&asoc->stream)); 3234 default: 3235 BUG(); 3236 } 3237 3238 if (chunk->chunk_hdr->flags & SCTP_DATA_SACK_IMM) 3239 force = SCTP_FORCE(); 3240 3241 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 3242 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3243 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 3244 } 3245 3246 /* If this is the last chunk in a packet, we need to count it 3247 * toward sack generation. Note that we need to SACK every 3248 * OTHER packet containing data chunks, EVEN IF WE DISCARD 3249 * THEM. We elect to NOT generate SACK's if the chunk fails 3250 * the verification tag test. 3251 * 3252 * RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3253 * 3254 * The SCTP endpoint MUST always acknowledge the reception of 3255 * each valid DATA chunk. 3256 * 3257 * The guidelines on delayed acknowledgement algorithm 3258 * specified in Section 4.2 of [RFC2581] SHOULD be followed. 3259 * Specifically, an acknowledgement SHOULD be generated for at 3260 * least every second packet (not every second DATA chunk) 3261 * received, and SHOULD be generated within 200 ms of the 3262 * arrival of any unacknowledged DATA chunk. In some 3263 * situations it may be beneficial for an SCTP transmitter to 3264 * be more conservative than the algorithms detailed in this 3265 * document allow. However, an SCTP transmitter MUST NOT be 3266 * more aggressive than the following algorithms allow. 3267 */ 3268 if (chunk->end_of_packet) 3269 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3270 3271 return SCTP_DISPOSITION_CONSUME; 3272 3273 discard_force: 3274 /* RFC 2960 6.2 Acknowledgement on Reception of DATA Chunks 3275 * 3276 * When a packet arrives with duplicate DATA chunk(s) and with 3277 * no new DATA chunk(s), the endpoint MUST immediately send a 3278 * SACK with no delay. If a packet arrives with duplicate 3279 * DATA chunk(s) bundled with new DATA chunks, the endpoint 3280 * MAY immediately send a SACK. Normally receipt of duplicate 3281 * DATA chunks will occur when the original SACK chunk was lost 3282 * and the peer's RTO has expired. The duplicate TSN number(s) 3283 * SHOULD be reported in the SACK as duplicate. 3284 */ 3285 /* In our case, we split the MAY SACK advice up whether or not 3286 * the last chunk is a duplicate.' 3287 */ 3288 if (chunk->end_of_packet) 3289 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3290 return SCTP_DISPOSITION_DISCARD; 3291 3292 discard_noforce: 3293 if (chunk->end_of_packet) 3294 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, force); 3295 3296 return SCTP_DISPOSITION_DISCARD; 3297 } 3298 3299 /* 3300 * sctp_sf_eat_data_fast_4_4 3301 * 3302 * Section: 4 (4) 3303 * (4) In SHUTDOWN-SENT state the endpoint MUST acknowledge any received 3304 * DATA chunks without delay. 3305 * 3306 * Verification Tag: 8.5 Verification Tag [Normal verification] 3307 * Inputs 3308 * (endpoint, asoc, chunk) 3309 * 3310 * Outputs 3311 * (asoc, reply_msg, msg_up, timers, counters) 3312 * 3313 * The return value is the disposition of the chunk. 3314 */ 3315 enum sctp_disposition sctp_sf_eat_data_fast_4_4( 3316 struct net *net, 3317 const struct sctp_endpoint *ep, 3318 const struct sctp_association *asoc, 3319 const union sctp_subtype type, 3320 void *arg, 3321 struct sctp_cmd_seq *commands) 3322 { 3323 struct sctp_chunk *chunk = arg; 3324 int error; 3325 3326 if (!sctp_vtag_verify(chunk, asoc)) { 3327 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3328 SCTP_NULL()); 3329 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3330 } 3331 3332 if (!sctp_chunk_length_valid(chunk, sctp_datachk_len(&asoc->stream))) 3333 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3334 commands); 3335 3336 error = sctp_eat_data(asoc, chunk, commands); 3337 switch (error) { 3338 case SCTP_IERROR_NO_ERROR: 3339 case SCTP_IERROR_HIGH_TSN: 3340 case SCTP_IERROR_DUP_TSN: 3341 case SCTP_IERROR_IGNORE_TSN: 3342 case SCTP_IERROR_BAD_STREAM: 3343 break; 3344 case SCTP_IERROR_NO_DATA: 3345 return SCTP_DISPOSITION_ABORT; 3346 case SCTP_IERROR_PROTO_VIOLATION: 3347 return sctp_sf_abort_violation(net, ep, asoc, chunk, commands, 3348 (u8 *)chunk->subh.data_hdr, 3349 sctp_datahdr_len(&asoc->stream)); 3350 default: 3351 BUG(); 3352 } 3353 3354 /* Go a head and force a SACK, since we are shutting down. */ 3355 3356 /* Implementor's Guide. 3357 * 3358 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 3359 * respond to each received packet containing one or more DATA chunk(s) 3360 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 3361 */ 3362 if (chunk->end_of_packet) { 3363 /* We must delay the chunk creation since the cumulative 3364 * TSN has not been updated yet. 3365 */ 3366 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 3367 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 3368 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 3369 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3370 } 3371 3372 return SCTP_DISPOSITION_CONSUME; 3373 } 3374 3375 /* 3376 * Section: 6.2 Processing a Received SACK 3377 * D) Any time a SACK arrives, the endpoint performs the following: 3378 * 3379 * i) If Cumulative TSN Ack is less than the Cumulative TSN Ack Point, 3380 * then drop the SACK. Since Cumulative TSN Ack is monotonically 3381 * increasing, a SACK whose Cumulative TSN Ack is less than the 3382 * Cumulative TSN Ack Point indicates an out-of-order SACK. 3383 * 3384 * ii) Set rwnd equal to the newly received a_rwnd minus the number 3385 * of bytes still outstanding after processing the Cumulative TSN Ack 3386 * and the Gap Ack Blocks. 3387 * 3388 * iii) If the SACK is missing a TSN that was previously 3389 * acknowledged via a Gap Ack Block (e.g., the data receiver 3390 * reneged on the data), then mark the corresponding DATA chunk 3391 * as available for retransmit: Mark it as missing for fast 3392 * retransmit as described in Section 7.2.4 and if no retransmit 3393 * timer is running for the destination address to which the DATA 3394 * chunk was originally transmitted, then T3-rtx is started for 3395 * that destination address. 3396 * 3397 * Verification Tag: 8.5 Verification Tag [Normal verification] 3398 * 3399 * Inputs 3400 * (endpoint, asoc, chunk) 3401 * 3402 * Outputs 3403 * (asoc, reply_msg, msg_up, timers, counters) 3404 * 3405 * The return value is the disposition of the chunk. 3406 */ 3407 enum sctp_disposition sctp_sf_eat_sack_6_2(struct net *net, 3408 const struct sctp_endpoint *ep, 3409 const struct sctp_association *asoc, 3410 const union sctp_subtype type, 3411 void *arg, 3412 struct sctp_cmd_seq *commands) 3413 { 3414 struct sctp_chunk *chunk = arg; 3415 struct sctp_sackhdr *sackh; 3416 __u32 ctsn; 3417 3418 if (!sctp_vtag_verify(chunk, asoc)) 3419 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3420 3421 /* Make sure that the SACK chunk has a valid length. */ 3422 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_sack_chunk))) 3423 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3424 commands); 3425 3426 /* Pull the SACK chunk from the data buffer */ 3427 sackh = sctp_sm_pull_sack(chunk); 3428 /* Was this a bogus SACK? */ 3429 if (!sackh) 3430 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3431 chunk->subh.sack_hdr = sackh; 3432 ctsn = ntohl(sackh->cum_tsn_ack); 3433 3434 /* If Cumulative TSN Ack beyond the max tsn currently 3435 * send, terminating the association and respond to the 3436 * sender with an ABORT. 3437 */ 3438 if (TSN_lte(asoc->next_tsn, ctsn)) 3439 return sctp_sf_violation_ctsn(net, ep, asoc, type, arg, commands); 3440 3441 trace_sctp_probe(ep, asoc, chunk); 3442 3443 /* i) If Cumulative TSN Ack is less than the Cumulative TSN 3444 * Ack Point, then drop the SACK. Since Cumulative TSN 3445 * Ack is monotonically increasing, a SACK whose 3446 * Cumulative TSN Ack is less than the Cumulative TSN Ack 3447 * Point indicates an out-of-order SACK. 3448 */ 3449 if (TSN_lt(ctsn, asoc->ctsn_ack_point)) { 3450 pr_debug("%s: ctsn:%x, ctsn_ack_point:%x\n", __func__, ctsn, 3451 asoc->ctsn_ack_point); 3452 3453 return SCTP_DISPOSITION_DISCARD; 3454 } 3455 3456 /* Return this SACK for further processing. */ 3457 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_SACK, SCTP_CHUNK(chunk)); 3458 3459 /* Note: We do the rest of the work on the PROCESS_SACK 3460 * sideeffect. 3461 */ 3462 return SCTP_DISPOSITION_CONSUME; 3463 } 3464 3465 /* 3466 * Generate an ABORT in response to a packet. 3467 * 3468 * Section: 8.4 Handle "Out of the blue" Packets, sctpimpguide 2.41 3469 * 3470 * 8) The receiver should respond to the sender of the OOTB packet with 3471 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3472 * MUST fill in the Verification Tag field of the outbound packet 3473 * with the value found in the Verification Tag field of the OOTB 3474 * packet and set the T-bit in the Chunk Flags to indicate that the 3475 * Verification Tag is reflected. After sending this ABORT, the 3476 * receiver of the OOTB packet shall discard the OOTB packet and take 3477 * no further action. 3478 * 3479 * Verification Tag: 3480 * 3481 * The return value is the disposition of the chunk. 3482 */ 3483 static enum sctp_disposition sctp_sf_tabort_8_4_8( 3484 struct net *net, 3485 const struct sctp_endpoint *ep, 3486 const struct sctp_association *asoc, 3487 const union sctp_subtype type, 3488 void *arg, 3489 struct sctp_cmd_seq *commands) 3490 { 3491 struct sctp_packet *packet = NULL; 3492 struct sctp_chunk *chunk = arg; 3493 struct sctp_chunk *abort; 3494 3495 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3496 if (!packet) 3497 return SCTP_DISPOSITION_NOMEM; 3498 3499 /* Make an ABORT. The T bit will be set if the asoc 3500 * is NULL. 3501 */ 3502 abort = sctp_make_abort(asoc, chunk, 0); 3503 if (!abort) { 3504 sctp_ootb_pkt_free(packet); 3505 return SCTP_DISPOSITION_NOMEM; 3506 } 3507 3508 /* Reflect vtag if T-Bit is set */ 3509 if (sctp_test_T_bit(abort)) 3510 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3511 3512 /* Set the skb to the belonging sock for accounting. */ 3513 abort->skb->sk = ep->base.sk; 3514 3515 sctp_packet_append_chunk(packet, abort); 3516 3517 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, SCTP_PACKET(packet)); 3518 3519 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3520 3521 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3522 return SCTP_DISPOSITION_CONSUME; 3523 } 3524 3525 /* Handling of SCTP Packets Containing an INIT Chunk Matching an 3526 * Existing Associations when the UDP encap port is incorrect. 3527 * 3528 * From Section 4 at draft-tuexen-tsvwg-sctp-udp-encaps-cons-03. 3529 */ 3530 static enum sctp_disposition sctp_sf_new_encap_port( 3531 struct net *net, 3532 const struct sctp_endpoint *ep, 3533 const struct sctp_association *asoc, 3534 const union sctp_subtype type, 3535 void *arg, 3536 struct sctp_cmd_seq *commands) 3537 { 3538 struct sctp_packet *packet = NULL; 3539 struct sctp_chunk *chunk = arg; 3540 struct sctp_chunk *abort; 3541 3542 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3543 if (!packet) 3544 return SCTP_DISPOSITION_NOMEM; 3545 3546 abort = sctp_make_new_encap_port(asoc, chunk); 3547 if (!abort) { 3548 sctp_ootb_pkt_free(packet); 3549 return SCTP_DISPOSITION_NOMEM; 3550 } 3551 3552 abort->skb->sk = ep->base.sk; 3553 3554 sctp_packet_append_chunk(packet, abort); 3555 3556 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3557 SCTP_PACKET(packet)); 3558 3559 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3560 3561 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3562 return SCTP_DISPOSITION_CONSUME; 3563 } 3564 3565 /* 3566 * Received an ERROR chunk from peer. Generate SCTP_REMOTE_ERROR 3567 * event as ULP notification for each cause included in the chunk. 3568 * 3569 * API 5.3.1.3 - SCTP_REMOTE_ERROR 3570 * 3571 * The return value is the disposition of the chunk. 3572 */ 3573 enum sctp_disposition sctp_sf_operr_notify(struct net *net, 3574 const struct sctp_endpoint *ep, 3575 const struct sctp_association *asoc, 3576 const union sctp_subtype type, 3577 void *arg, 3578 struct sctp_cmd_seq *commands) 3579 { 3580 struct sctp_chunk *chunk = arg; 3581 struct sctp_errhdr *err; 3582 3583 if (!sctp_vtag_verify(chunk, asoc)) 3584 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3585 3586 /* Make sure that the ERROR chunk has a valid length. */ 3587 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_operr_chunk))) 3588 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3589 commands); 3590 sctp_walk_errors(err, chunk->chunk_hdr); 3591 if ((void *)err != (void *)chunk->chunk_end) 3592 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3593 (void *)err, commands); 3594 3595 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_OPERR, 3596 SCTP_CHUNK(chunk)); 3597 3598 return SCTP_DISPOSITION_CONSUME; 3599 } 3600 3601 /* 3602 * Process an inbound SHUTDOWN ACK. 3603 * 3604 * From Section 9.2: 3605 * Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3606 * stop the T2-shutdown timer, send a SHUTDOWN COMPLETE chunk to its 3607 * peer, and remove all record of the association. 3608 * 3609 * The return value is the disposition. 3610 */ 3611 enum sctp_disposition sctp_sf_do_9_2_final(struct net *net, 3612 const struct sctp_endpoint *ep, 3613 const struct sctp_association *asoc, 3614 const union sctp_subtype type, 3615 void *arg, 3616 struct sctp_cmd_seq *commands) 3617 { 3618 struct sctp_chunk *chunk = arg; 3619 struct sctp_chunk *reply; 3620 struct sctp_ulpevent *ev; 3621 3622 if (!sctp_vtag_verify(chunk, asoc)) 3623 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3624 3625 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3626 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3627 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3628 commands); 3629 /* 10.2 H) SHUTDOWN COMPLETE notification 3630 * 3631 * When SCTP completes the shutdown procedures (section 9.2) this 3632 * notification is passed to the upper layer. 3633 */ 3634 ev = sctp_ulpevent_make_assoc_change(asoc, 0, SCTP_SHUTDOWN_COMP, 3635 0, 0, 0, NULL, GFP_ATOMIC); 3636 if (!ev) 3637 goto nomem; 3638 3639 /* ...send a SHUTDOWN COMPLETE chunk to its peer, */ 3640 reply = sctp_make_shutdown_complete(asoc, chunk); 3641 if (!reply) 3642 goto nomem_chunk; 3643 3644 /* Do all the commands now (after allocation), so that we 3645 * have consistent state if memory allocation fails 3646 */ 3647 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(ev)); 3648 3649 /* Upon the receipt of the SHUTDOWN ACK, the SHUTDOWN sender shall 3650 * stop the T2-shutdown timer, 3651 */ 3652 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3653 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 3654 3655 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 3656 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 3657 3658 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 3659 SCTP_STATE(SCTP_STATE_CLOSED)); 3660 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 3661 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 3662 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 3663 3664 /* ...and remove all record of the association. */ 3665 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 3666 return SCTP_DISPOSITION_DELETE_TCB; 3667 3668 nomem_chunk: 3669 sctp_ulpevent_free(ev); 3670 nomem: 3671 return SCTP_DISPOSITION_NOMEM; 3672 } 3673 3674 /* 3675 * RFC 2960, 8.4 - Handle "Out of the blue" Packets, sctpimpguide 2.41. 3676 * 3677 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3678 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3679 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3680 * packet must fill in the Verification Tag field of the outbound 3681 * packet with the Verification Tag received in the SHUTDOWN ACK and 3682 * set the T-bit in the Chunk Flags to indicate that the Verification 3683 * Tag is reflected. 3684 * 3685 * 8) The receiver should respond to the sender of the OOTB packet with 3686 * an ABORT. When sending the ABORT, the receiver of the OOTB packet 3687 * MUST fill in the Verification Tag field of the outbound packet 3688 * with the value found in the Verification Tag field of the OOTB 3689 * packet and set the T-bit in the Chunk Flags to indicate that the 3690 * Verification Tag is reflected. After sending this ABORT, the 3691 * receiver of the OOTB packet shall discard the OOTB packet and take 3692 * no further action. 3693 */ 3694 enum sctp_disposition sctp_sf_ootb(struct net *net, 3695 const struct sctp_endpoint *ep, 3696 const struct sctp_association *asoc, 3697 const union sctp_subtype type, 3698 void *arg, struct sctp_cmd_seq *commands) 3699 { 3700 struct sctp_chunk *chunk = arg; 3701 struct sk_buff *skb = chunk->skb; 3702 struct sctp_chunkhdr *ch; 3703 struct sctp_errhdr *err; 3704 int ootb_cookie_ack = 0; 3705 int ootb_shut_ack = 0; 3706 __u8 *ch_end; 3707 3708 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3709 3710 if (asoc && !sctp_vtag_verify(chunk, asoc)) 3711 asoc = NULL; 3712 3713 ch = (struct sctp_chunkhdr *)chunk->chunk_hdr; 3714 do { 3715 /* Report violation if the chunk is less then minimal */ 3716 if (ntohs(ch->length) < sizeof(*ch)) 3717 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3718 commands); 3719 3720 /* Report violation if chunk len overflows */ 3721 ch_end = ((__u8 *)ch) + SCTP_PAD4(ntohs(ch->length)); 3722 if (ch_end > skb_tail_pointer(skb)) 3723 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3724 commands); 3725 3726 /* Now that we know we at least have a chunk header, 3727 * do things that are type appropriate. 3728 */ 3729 if (SCTP_CID_SHUTDOWN_ACK == ch->type) 3730 ootb_shut_ack = 1; 3731 3732 /* RFC 2960, Section 3.3.7 3733 * Moreover, under any circumstances, an endpoint that 3734 * receives an ABORT MUST NOT respond to that ABORT by 3735 * sending an ABORT of its own. 3736 */ 3737 if (SCTP_CID_ABORT == ch->type) 3738 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3739 3740 /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR 3741 * or a COOKIE ACK the SCTP Packet should be silently 3742 * discarded. 3743 */ 3744 3745 if (SCTP_CID_COOKIE_ACK == ch->type) 3746 ootb_cookie_ack = 1; 3747 3748 if (SCTP_CID_ERROR == ch->type) { 3749 sctp_walk_errors(err, ch) { 3750 if (SCTP_ERROR_STALE_COOKIE == err->cause) { 3751 ootb_cookie_ack = 1; 3752 break; 3753 } 3754 } 3755 } 3756 3757 ch = (struct sctp_chunkhdr *)ch_end; 3758 } while (ch_end + sizeof(*ch) < skb_tail_pointer(skb)); 3759 3760 if (ootb_shut_ack) 3761 return sctp_sf_shut_8_4_5(net, ep, asoc, type, arg, commands); 3762 else if (ootb_cookie_ack) 3763 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3764 else 3765 return sctp_sf_tabort_8_4_8(net, ep, asoc, type, arg, commands); 3766 } 3767 3768 /* 3769 * Handle an "Out of the blue" SHUTDOWN ACK. 3770 * 3771 * Section: 8.4 5, sctpimpguide 2.41. 3772 * 3773 * 5) If the packet contains a SHUTDOWN ACK chunk, the receiver should 3774 * respond to the sender of the OOTB packet with a SHUTDOWN COMPLETE. 3775 * When sending the SHUTDOWN COMPLETE, the receiver of the OOTB 3776 * packet must fill in the Verification Tag field of the outbound 3777 * packet with the Verification Tag received in the SHUTDOWN ACK and 3778 * set the T-bit in the Chunk Flags to indicate that the Verification 3779 * Tag is reflected. 3780 * 3781 * Inputs 3782 * (endpoint, asoc, type, arg, commands) 3783 * 3784 * Outputs 3785 * (enum sctp_disposition) 3786 * 3787 * The return value is the disposition of the chunk. 3788 */ 3789 static enum sctp_disposition sctp_sf_shut_8_4_5( 3790 struct net *net, 3791 const struct sctp_endpoint *ep, 3792 const struct sctp_association *asoc, 3793 const union sctp_subtype type, 3794 void *arg, 3795 struct sctp_cmd_seq *commands) 3796 { 3797 struct sctp_packet *packet = NULL; 3798 struct sctp_chunk *chunk = arg; 3799 struct sctp_chunk *shut; 3800 3801 packet = sctp_ootb_pkt_new(net, asoc, chunk); 3802 if (!packet) 3803 return SCTP_DISPOSITION_NOMEM; 3804 3805 /* Make an SHUTDOWN_COMPLETE. 3806 * The T bit will be set if the asoc is NULL. 3807 */ 3808 shut = sctp_make_shutdown_complete(asoc, chunk); 3809 if (!shut) { 3810 sctp_ootb_pkt_free(packet); 3811 return SCTP_DISPOSITION_NOMEM; 3812 } 3813 3814 /* Reflect vtag if T-Bit is set */ 3815 if (sctp_test_T_bit(shut)) 3816 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 3817 3818 /* Set the skb to the belonging sock for accounting. */ 3819 shut->skb->sk = ep->base.sk; 3820 3821 sctp_packet_append_chunk(packet, shut); 3822 3823 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 3824 SCTP_PACKET(packet)); 3825 3826 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 3827 3828 /* We need to discard the rest of the packet to prevent 3829 * potential boomming attacks from additional bundled chunks. 3830 * This is documented in SCTP Threats ID. 3831 */ 3832 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3833 } 3834 3835 /* 3836 * Handle SHUTDOWN ACK in COOKIE_ECHOED or COOKIE_WAIT state. 3837 * 3838 * Verification Tag: 8.5.1 E) Rules for packet carrying a SHUTDOWN ACK 3839 * If the receiver is in COOKIE-ECHOED or COOKIE-WAIT state the 3840 * procedures in section 8.4 SHOULD be followed, in other words it 3841 * should be treated as an Out Of The Blue packet. 3842 * [This means that we do NOT check the Verification Tag on these 3843 * chunks. --piggy ] 3844 * 3845 */ 3846 enum sctp_disposition sctp_sf_do_8_5_1_E_sa(struct net *net, 3847 const struct sctp_endpoint *ep, 3848 const struct sctp_association *asoc, 3849 const union sctp_subtype type, 3850 void *arg, 3851 struct sctp_cmd_seq *commands) 3852 { 3853 struct sctp_chunk *chunk = arg; 3854 3855 if (!sctp_vtag_verify(chunk, asoc)) 3856 asoc = NULL; 3857 3858 /* Make sure that the SHUTDOWN_ACK chunk has a valid length. */ 3859 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 3860 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3861 commands); 3862 3863 /* Although we do have an association in this case, it corresponds 3864 * to a restarted association. So the packet is treated as an OOTB 3865 * packet and the state function that handles OOTB SHUTDOWN_ACK is 3866 * called with a NULL association. 3867 */ 3868 SCTP_INC_STATS(net, SCTP_MIB_OUTOFBLUES); 3869 3870 return sctp_sf_shut_8_4_5(net, ep, NULL, type, arg, commands); 3871 } 3872 3873 /* ADDIP Section 4.2 Upon reception of an ASCONF Chunk. */ 3874 enum sctp_disposition sctp_sf_do_asconf(struct net *net, 3875 const struct sctp_endpoint *ep, 3876 const struct sctp_association *asoc, 3877 const union sctp_subtype type, 3878 void *arg, 3879 struct sctp_cmd_seq *commands) 3880 { 3881 struct sctp_paramhdr *err_param = NULL; 3882 struct sctp_chunk *asconf_ack = NULL; 3883 struct sctp_chunk *chunk = arg; 3884 struct sctp_addiphdr *hdr; 3885 __u32 serial; 3886 3887 if (!sctp_vtag_verify(chunk, asoc)) { 3888 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 3889 SCTP_NULL()); 3890 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3891 } 3892 3893 /* Make sure that the ASCONF ADDIP chunk has a valid length. */ 3894 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_addip_chunk))) 3895 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 3896 commands); 3897 3898 /* ADD-IP: Section 4.1.1 3899 * This chunk MUST be sent in an authenticated way by using 3900 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 3901 * is received unauthenticated it MUST be silently discarded as 3902 * described in [I-D.ietf-tsvwg-sctp-auth]. 3903 */ 3904 if (!asoc->peer.asconf_capable || 3905 (!net->sctp.addip_noauth && !chunk->auth)) 3906 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 3907 3908 hdr = (struct sctp_addiphdr *)chunk->skb->data; 3909 serial = ntohl(hdr->serial); 3910 3911 /* Verify the ASCONF chunk before processing it. */ 3912 if (!sctp_verify_asconf(asoc, chunk, true, &err_param)) 3913 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 3914 (void *)err_param, commands); 3915 3916 /* ADDIP 5.2 E1) Compare the value of the serial number to the value 3917 * the endpoint stored in a new association variable 3918 * 'Peer-Serial-Number'. 3919 */ 3920 if (serial == asoc->peer.addip_serial + 1) { 3921 /* If this is the first instance of ASCONF in the packet, 3922 * we can clean our old ASCONF-ACKs. 3923 */ 3924 if (!chunk->has_asconf) 3925 sctp_assoc_clean_asconf_ack_cache(asoc); 3926 3927 /* ADDIP 5.2 E4) When the Sequence Number matches the next one 3928 * expected, process the ASCONF as described below and after 3929 * processing the ASCONF Chunk, append an ASCONF-ACK Chunk to 3930 * the response packet and cache a copy of it (in the event it 3931 * later needs to be retransmitted). 3932 * 3933 * Essentially, do V1-V5. 3934 */ 3935 asconf_ack = sctp_process_asconf((struct sctp_association *) 3936 asoc, chunk); 3937 if (!asconf_ack) 3938 return SCTP_DISPOSITION_NOMEM; 3939 } else if (serial < asoc->peer.addip_serial + 1) { 3940 /* ADDIP 5.2 E2) 3941 * If the value found in the Sequence Number is less than the 3942 * ('Peer- Sequence-Number' + 1), simply skip to the next 3943 * ASCONF, and include in the outbound response packet 3944 * any previously cached ASCONF-ACK response that was 3945 * sent and saved that matches the Sequence Number of the 3946 * ASCONF. Note: It is possible that no cached ASCONF-ACK 3947 * Chunk exists. This will occur when an older ASCONF 3948 * arrives out of order. In such a case, the receiver 3949 * should skip the ASCONF Chunk and not include ASCONF-ACK 3950 * Chunk for that chunk. 3951 */ 3952 asconf_ack = sctp_assoc_lookup_asconf_ack(asoc, hdr->serial); 3953 if (!asconf_ack) 3954 return SCTP_DISPOSITION_DISCARD; 3955 3956 /* Reset the transport so that we select the correct one 3957 * this time around. This is to make sure that we don't 3958 * accidentally use a stale transport that's been removed. 3959 */ 3960 asconf_ack->transport = NULL; 3961 } else { 3962 /* ADDIP 5.2 E5) Otherwise, the ASCONF Chunk is discarded since 3963 * it must be either a stale packet or from an attacker. 3964 */ 3965 return SCTP_DISPOSITION_DISCARD; 3966 } 3967 3968 /* ADDIP 5.2 E6) The destination address of the SCTP packet 3969 * containing the ASCONF-ACK Chunks MUST be the source address of 3970 * the SCTP packet that held the ASCONF Chunks. 3971 * 3972 * To do this properly, we'll set the destination address of the chunk 3973 * and at the transmit time, will try look up the transport to use. 3974 * Since ASCONFs may be bundled, the correct transport may not be 3975 * created until we process the entire packet, thus this workaround. 3976 */ 3977 asconf_ack->dest = chunk->source; 3978 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(asconf_ack)); 3979 if (asoc->new_transport) { 3980 sctp_sf_heartbeat(ep, asoc, type, asoc->new_transport, commands); 3981 ((struct sctp_association *)asoc)->new_transport = NULL; 3982 } 3983 3984 return SCTP_DISPOSITION_CONSUME; 3985 } 3986 3987 static enum sctp_disposition sctp_send_next_asconf( 3988 struct net *net, 3989 const struct sctp_endpoint *ep, 3990 struct sctp_association *asoc, 3991 const union sctp_subtype type, 3992 struct sctp_cmd_seq *commands) 3993 { 3994 struct sctp_chunk *asconf; 3995 struct list_head *entry; 3996 3997 if (list_empty(&asoc->addip_chunk_list)) 3998 return SCTP_DISPOSITION_CONSUME; 3999 4000 entry = asoc->addip_chunk_list.next; 4001 asconf = list_entry(entry, struct sctp_chunk, list); 4002 4003 list_del_init(entry); 4004 sctp_chunk_hold(asconf); 4005 asoc->addip_last_asconf = asconf; 4006 4007 return sctp_sf_do_prm_asconf(net, ep, asoc, type, asconf, commands); 4008 } 4009 4010 /* 4011 * ADDIP Section 4.3 General rules for address manipulation 4012 * When building TLV parameters for the ASCONF Chunk that will add or 4013 * delete IP addresses the D0 to D13 rules should be applied: 4014 */ 4015 enum sctp_disposition sctp_sf_do_asconf_ack(struct net *net, 4016 const struct sctp_endpoint *ep, 4017 const struct sctp_association *asoc, 4018 const union sctp_subtype type, 4019 void *arg, 4020 struct sctp_cmd_seq *commands) 4021 { 4022 struct sctp_chunk *last_asconf = asoc->addip_last_asconf; 4023 struct sctp_paramhdr *err_param = NULL; 4024 struct sctp_chunk *asconf_ack = arg; 4025 struct sctp_addiphdr *addip_hdr; 4026 __u32 sent_serial, rcvd_serial; 4027 struct sctp_chunk *abort; 4028 4029 if (!sctp_vtag_verify(asconf_ack, asoc)) { 4030 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4031 SCTP_NULL()); 4032 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4033 } 4034 4035 /* Make sure that the ADDIP chunk has a valid length. */ 4036 if (!sctp_chunk_length_valid(asconf_ack, 4037 sizeof(struct sctp_addip_chunk))) 4038 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4039 commands); 4040 4041 /* ADD-IP, Section 4.1.2: 4042 * This chunk MUST be sent in an authenticated way by using 4043 * the mechanism defined in [I-D.ietf-tsvwg-sctp-auth]. If this chunk 4044 * is received unauthenticated it MUST be silently discarded as 4045 * described in [I-D.ietf-tsvwg-sctp-auth]. 4046 */ 4047 if (!asoc->peer.asconf_capable || 4048 (!net->sctp.addip_noauth && !asconf_ack->auth)) 4049 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4050 4051 addip_hdr = (struct sctp_addiphdr *)asconf_ack->skb->data; 4052 rcvd_serial = ntohl(addip_hdr->serial); 4053 4054 /* Verify the ASCONF-ACK chunk before processing it. */ 4055 if (!sctp_verify_asconf(asoc, asconf_ack, false, &err_param)) 4056 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 4057 (void *)err_param, commands); 4058 4059 if (last_asconf) { 4060 addip_hdr = last_asconf->subh.addip_hdr; 4061 sent_serial = ntohl(addip_hdr->serial); 4062 } else { 4063 sent_serial = asoc->addip_serial - 1; 4064 } 4065 4066 /* D0) If an endpoint receives an ASCONF-ACK that is greater than or 4067 * equal to the next serial number to be used but no ASCONF chunk is 4068 * outstanding the endpoint MUST ABORT the association. Note that a 4069 * sequence number is greater than if it is no more than 2^^31-1 4070 * larger than the current sequence number (using serial arithmetic). 4071 */ 4072 if (ADDIP_SERIAL_gte(rcvd_serial, sent_serial + 1) && 4073 !(asoc->addip_last_asconf)) { 4074 abort = sctp_make_abort(asoc, asconf_ack, 4075 sizeof(struct sctp_errhdr)); 4076 if (abort) { 4077 sctp_init_cause(abort, SCTP_ERROR_ASCONF_ACK, 0); 4078 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4079 SCTP_CHUNK(abort)); 4080 } 4081 /* We are going to ABORT, so we might as well stop 4082 * processing the rest of the chunks in the packet. 4083 */ 4084 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4085 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 4086 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4087 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4088 SCTP_ERROR(ECONNABORTED)); 4089 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4090 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 4091 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4092 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4093 return SCTP_DISPOSITION_ABORT; 4094 } 4095 4096 if ((rcvd_serial == sent_serial) && asoc->addip_last_asconf) { 4097 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4098 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 4099 4100 if (!sctp_process_asconf_ack((struct sctp_association *)asoc, 4101 asconf_ack)) 4102 return sctp_send_next_asconf(net, ep, 4103 (struct sctp_association *)asoc, 4104 type, commands); 4105 4106 abort = sctp_make_abort(asoc, asconf_ack, 4107 sizeof(struct sctp_errhdr)); 4108 if (abort) { 4109 sctp_init_cause(abort, SCTP_ERROR_RSRC_LOW, 0); 4110 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4111 SCTP_CHUNK(abort)); 4112 } 4113 /* We are going to ABORT, so we might as well stop 4114 * processing the rest of the chunks in the packet. 4115 */ 4116 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4117 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4118 SCTP_ERROR(ECONNABORTED)); 4119 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4120 SCTP_PERR(SCTP_ERROR_ASCONF_ACK)); 4121 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4122 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4123 return SCTP_DISPOSITION_ABORT; 4124 } 4125 4126 return SCTP_DISPOSITION_DISCARD; 4127 } 4128 4129 /* RE-CONFIG Section 5.2 Upon reception of an RECONF Chunk. */ 4130 enum sctp_disposition sctp_sf_do_reconf(struct net *net, 4131 const struct sctp_endpoint *ep, 4132 const struct sctp_association *asoc, 4133 const union sctp_subtype type, 4134 void *arg, 4135 struct sctp_cmd_seq *commands) 4136 { 4137 struct sctp_paramhdr *err_param = NULL; 4138 struct sctp_chunk *chunk = arg; 4139 struct sctp_reconf_chunk *hdr; 4140 union sctp_params param; 4141 4142 if (!sctp_vtag_verify(chunk, asoc)) { 4143 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4144 SCTP_NULL()); 4145 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4146 } 4147 4148 /* Make sure that the RECONF chunk has a valid length. */ 4149 if (!sctp_chunk_length_valid(chunk, sizeof(*hdr))) 4150 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4151 commands); 4152 4153 if (!sctp_verify_reconf(asoc, chunk, &err_param)) 4154 return sctp_sf_violation_paramlen(net, ep, asoc, type, arg, 4155 (void *)err_param, commands); 4156 4157 hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr; 4158 sctp_walk_params(param, hdr) { 4159 struct sctp_chunk *reply = NULL; 4160 struct sctp_ulpevent *ev = NULL; 4161 4162 if (param.p->type == SCTP_PARAM_RESET_OUT_REQUEST) 4163 reply = sctp_process_strreset_outreq( 4164 (struct sctp_association *)asoc, param, &ev); 4165 else if (param.p->type == SCTP_PARAM_RESET_IN_REQUEST) 4166 reply = sctp_process_strreset_inreq( 4167 (struct sctp_association *)asoc, param, &ev); 4168 else if (param.p->type == SCTP_PARAM_RESET_TSN_REQUEST) 4169 reply = sctp_process_strreset_tsnreq( 4170 (struct sctp_association *)asoc, param, &ev); 4171 else if (param.p->type == SCTP_PARAM_RESET_ADD_OUT_STREAMS) 4172 reply = sctp_process_strreset_addstrm_out( 4173 (struct sctp_association *)asoc, param, &ev); 4174 else if (param.p->type == SCTP_PARAM_RESET_ADD_IN_STREAMS) 4175 reply = sctp_process_strreset_addstrm_in( 4176 (struct sctp_association *)asoc, param, &ev); 4177 else if (param.p->type == SCTP_PARAM_RESET_RESPONSE) 4178 reply = sctp_process_strreset_resp( 4179 (struct sctp_association *)asoc, param, &ev); 4180 4181 if (ev) 4182 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4183 SCTP_ULPEVENT(ev)); 4184 4185 if (reply) 4186 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4187 SCTP_CHUNK(reply)); 4188 } 4189 4190 return SCTP_DISPOSITION_CONSUME; 4191 } 4192 4193 /* 4194 * PR-SCTP Section 3.6 Receiver Side Implementation of PR-SCTP 4195 * 4196 * When a FORWARD TSN chunk arrives, the data receiver MUST first update 4197 * its cumulative TSN point to the value carried in the FORWARD TSN 4198 * chunk, and then MUST further advance its cumulative TSN point locally 4199 * if possible. 4200 * After the above processing, the data receiver MUST stop reporting any 4201 * missing TSNs earlier than or equal to the new cumulative TSN point. 4202 * 4203 * Verification Tag: 8.5 Verification Tag [Normal verification] 4204 * 4205 * The return value is the disposition of the chunk. 4206 */ 4207 enum sctp_disposition sctp_sf_eat_fwd_tsn(struct net *net, 4208 const struct sctp_endpoint *ep, 4209 const struct sctp_association *asoc, 4210 const union sctp_subtype type, 4211 void *arg, 4212 struct sctp_cmd_seq *commands) 4213 { 4214 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 4215 struct sctp_chunk *chunk = arg; 4216 __u16 len; 4217 __u32 tsn; 4218 4219 if (!sctp_vtag_verify(chunk, asoc)) { 4220 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4221 SCTP_NULL()); 4222 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4223 } 4224 4225 if (!asoc->peer.prsctp_capable) 4226 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4227 4228 /* Make sure that the FORWARD_TSN chunk has valid length. */ 4229 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream))) 4230 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4231 commands); 4232 4233 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 4234 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 4235 len = ntohs(chunk->chunk_hdr->length); 4236 len -= sizeof(struct sctp_chunkhdr); 4237 skb_pull(chunk->skb, len); 4238 4239 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 4240 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 4241 4242 /* The TSN is too high--silently discard the chunk and count on it 4243 * getting retransmitted later. 4244 */ 4245 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 4246 goto discard_noforce; 4247 4248 if (!asoc->stream.si->validate_ftsn(chunk)) 4249 goto discard_noforce; 4250 4251 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 4252 if (len > sctp_ftsnhdr_len(&asoc->stream)) 4253 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 4254 SCTP_CHUNK(chunk)); 4255 4256 /* Count this as receiving DATA. */ 4257 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) { 4258 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4259 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 4260 } 4261 4262 /* FIXME: For now send a SACK, but DATA processing may 4263 * send another. 4264 */ 4265 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_NOFORCE()); 4266 4267 return SCTP_DISPOSITION_CONSUME; 4268 4269 discard_noforce: 4270 return SCTP_DISPOSITION_DISCARD; 4271 } 4272 4273 enum sctp_disposition sctp_sf_eat_fwd_tsn_fast( 4274 struct net *net, 4275 const struct sctp_endpoint *ep, 4276 const struct sctp_association *asoc, 4277 const union sctp_subtype type, 4278 void *arg, 4279 struct sctp_cmd_seq *commands) 4280 { 4281 struct sctp_fwdtsn_hdr *fwdtsn_hdr; 4282 struct sctp_chunk *chunk = arg; 4283 __u16 len; 4284 __u32 tsn; 4285 4286 if (!sctp_vtag_verify(chunk, asoc)) { 4287 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4288 SCTP_NULL()); 4289 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4290 } 4291 4292 if (!asoc->peer.prsctp_capable) 4293 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4294 4295 /* Make sure that the FORWARD_TSN chunk has a valid length. */ 4296 if (!sctp_chunk_length_valid(chunk, sctp_ftsnchk_len(&asoc->stream))) 4297 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4298 commands); 4299 4300 fwdtsn_hdr = (struct sctp_fwdtsn_hdr *)chunk->skb->data; 4301 chunk->subh.fwdtsn_hdr = fwdtsn_hdr; 4302 len = ntohs(chunk->chunk_hdr->length); 4303 len -= sizeof(struct sctp_chunkhdr); 4304 skb_pull(chunk->skb, len); 4305 4306 tsn = ntohl(fwdtsn_hdr->new_cum_tsn); 4307 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 4308 4309 /* The TSN is too high--silently discard the chunk and count on it 4310 * getting retransmitted later. 4311 */ 4312 if (sctp_tsnmap_check(&asoc->peer.tsn_map, tsn) < 0) 4313 goto gen_shutdown; 4314 4315 if (!asoc->stream.si->validate_ftsn(chunk)) 4316 goto gen_shutdown; 4317 4318 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_FWDTSN, SCTP_U32(tsn)); 4319 if (len > sctp_ftsnhdr_len(&asoc->stream)) 4320 sctp_add_cmd_sf(commands, SCTP_CMD_PROCESS_FWDTSN, 4321 SCTP_CHUNK(chunk)); 4322 4323 /* Go a head and force a SACK, since we are shutting down. */ 4324 gen_shutdown: 4325 /* Implementor's Guide. 4326 * 4327 * While in SHUTDOWN-SENT state, the SHUTDOWN sender MUST immediately 4328 * respond to each received packet containing one or more DATA chunk(s) 4329 * with a SACK, a SHUTDOWN chunk, and restart the T2-shutdown timer 4330 */ 4331 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SHUTDOWN, SCTP_NULL()); 4332 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 4333 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 4334 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 4335 4336 return SCTP_DISPOSITION_CONSUME; 4337 } 4338 4339 /* 4340 * SCTP-AUTH Section 6.3 Receiving authenticated chunks 4341 * 4342 * The receiver MUST use the HMAC algorithm indicated in the HMAC 4343 * Identifier field. If this algorithm was not specified by the 4344 * receiver in the HMAC-ALGO parameter in the INIT or INIT-ACK chunk 4345 * during association setup, the AUTH chunk and all chunks after it MUST 4346 * be discarded and an ERROR chunk SHOULD be sent with the error cause 4347 * defined in Section 4.1. 4348 * 4349 * If an endpoint with no shared key receives a Shared Key Identifier 4350 * other than 0, it MUST silently discard all authenticated chunks. If 4351 * the endpoint has at least one endpoint pair shared key for the peer, 4352 * it MUST use the key specified by the Shared Key Identifier if a 4353 * key has been configured for that Shared Key Identifier. If no 4354 * endpoint pair shared key has been configured for that Shared Key 4355 * Identifier, all authenticated chunks MUST be silently discarded. 4356 * 4357 * Verification Tag: 8.5 Verification Tag [Normal verification] 4358 * 4359 * The return value is the disposition of the chunk. 4360 */ 4361 static enum sctp_ierror sctp_sf_authenticate( 4362 const struct sctp_association *asoc, 4363 struct sctp_chunk *chunk) 4364 { 4365 struct sctp_shared_key *sh_key = NULL; 4366 struct sctp_authhdr *auth_hdr; 4367 __u8 *save_digest, *digest; 4368 const struct sctp_hmac *hmac; 4369 unsigned int sig_len; 4370 __u16 key_id; 4371 4372 /* Pull in the auth header, so we can do some more verification */ 4373 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4374 chunk->subh.auth_hdr = auth_hdr; 4375 skb_pull(chunk->skb, sizeof(*auth_hdr)); 4376 4377 /* Make sure that we support the HMAC algorithm from the auth 4378 * chunk. 4379 */ 4380 if (!sctp_auth_asoc_verify_hmac_id(asoc, auth_hdr->hmac_id)) 4381 return SCTP_IERROR_AUTH_BAD_HMAC; 4382 4383 /* Make sure that the provided shared key identifier has been 4384 * configured 4385 */ 4386 key_id = ntohs(auth_hdr->shkey_id); 4387 if (key_id != asoc->active_key_id) { 4388 sh_key = sctp_auth_get_shkey(asoc, key_id); 4389 if (!sh_key) 4390 return SCTP_IERROR_AUTH_BAD_KEYID; 4391 } 4392 4393 /* Make sure that the length of the signature matches what 4394 * we expect. 4395 */ 4396 sig_len = ntohs(chunk->chunk_hdr->length) - 4397 sizeof(struct sctp_auth_chunk); 4398 hmac = sctp_auth_get_hmac(ntohs(auth_hdr->hmac_id)); 4399 if (sig_len != hmac->hmac_len) 4400 return SCTP_IERROR_PROTO_VIOLATION; 4401 4402 /* Now that we've done validation checks, we can compute and 4403 * verify the hmac. The steps involved are: 4404 * 1. Save the digest from the chunk. 4405 * 2. Zero out the digest in the chunk. 4406 * 3. Compute the new digest 4407 * 4. Compare saved and new digests. 4408 */ 4409 digest = (u8 *)(auth_hdr + 1); 4410 skb_pull(chunk->skb, sig_len); 4411 4412 save_digest = kmemdup(digest, sig_len, GFP_ATOMIC); 4413 if (!save_digest) 4414 goto nomem; 4415 4416 memset(digest, 0, sig_len); 4417 4418 sctp_auth_calculate_hmac(asoc, chunk->skb, 4419 (struct sctp_auth_chunk *)chunk->chunk_hdr, 4420 sh_key, GFP_ATOMIC); 4421 4422 /* Discard the packet if the digests do not match */ 4423 if (crypto_memneq(save_digest, digest, sig_len)) { 4424 kfree(save_digest); 4425 return SCTP_IERROR_BAD_SIG; 4426 } 4427 4428 kfree(save_digest); 4429 chunk->auth = 1; 4430 4431 return SCTP_IERROR_NO_ERROR; 4432 nomem: 4433 return SCTP_IERROR_NOMEM; 4434 } 4435 4436 enum sctp_disposition sctp_sf_eat_auth(struct net *net, 4437 const struct sctp_endpoint *ep, 4438 const struct sctp_association *asoc, 4439 const union sctp_subtype type, 4440 void *arg, struct sctp_cmd_seq *commands) 4441 { 4442 struct sctp_chunk *chunk = arg; 4443 struct sctp_authhdr *auth_hdr; 4444 struct sctp_chunk *err_chunk; 4445 enum sctp_ierror error; 4446 4447 /* Make sure that the peer has AUTH capable */ 4448 if (!asoc->peer.auth_capable) 4449 return sctp_sf_unk_chunk(net, ep, asoc, type, arg, commands); 4450 4451 if (!sctp_vtag_verify(chunk, asoc)) { 4452 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_BAD_TAG, 4453 SCTP_NULL()); 4454 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4455 } 4456 4457 /* Make sure that the AUTH chunk has valid length. */ 4458 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_auth_chunk))) 4459 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4460 commands); 4461 4462 auth_hdr = (struct sctp_authhdr *)chunk->skb->data; 4463 error = sctp_sf_authenticate(asoc, chunk); 4464 switch (error) { 4465 case SCTP_IERROR_AUTH_BAD_HMAC: 4466 /* Generate the ERROR chunk and discard the rest 4467 * of the packet 4468 */ 4469 err_chunk = sctp_make_op_error(asoc, chunk, 4470 SCTP_ERROR_UNSUP_HMAC, 4471 &auth_hdr->hmac_id, 4472 sizeof(__u16), 0); 4473 if (err_chunk) { 4474 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4475 SCTP_CHUNK(err_chunk)); 4476 } 4477 fallthrough; 4478 case SCTP_IERROR_AUTH_BAD_KEYID: 4479 case SCTP_IERROR_BAD_SIG: 4480 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4481 4482 case SCTP_IERROR_PROTO_VIOLATION: 4483 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4484 commands); 4485 4486 case SCTP_IERROR_NOMEM: 4487 return SCTP_DISPOSITION_NOMEM; 4488 4489 default: /* Prevent gcc warnings */ 4490 break; 4491 } 4492 4493 if (asoc->active_key_id != ntohs(auth_hdr->shkey_id)) { 4494 struct sctp_ulpevent *ev; 4495 4496 ev = sctp_ulpevent_make_authkey(asoc, ntohs(auth_hdr->shkey_id), 4497 SCTP_AUTH_NEW_KEY, GFP_ATOMIC); 4498 4499 if (!ev) 4500 return SCTP_DISPOSITION_NOMEM; 4501 4502 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, 4503 SCTP_ULPEVENT(ev)); 4504 } 4505 4506 return SCTP_DISPOSITION_CONSUME; 4507 } 4508 4509 /* 4510 * Process an unknown chunk. 4511 * 4512 * Section: 3.2. Also, 2.1 in the implementor's guide. 4513 * 4514 * Chunk Types are encoded such that the highest-order two bits specify 4515 * the action that must be taken if the processing endpoint does not 4516 * recognize the Chunk Type. 4517 * 4518 * 00 - Stop processing this SCTP packet and discard it, do not process 4519 * any further chunks within it. 4520 * 4521 * 01 - Stop processing this SCTP packet and discard it, do not process 4522 * any further chunks within it, and report the unrecognized 4523 * chunk in an 'Unrecognized Chunk Type'. 4524 * 4525 * 10 - Skip this chunk and continue processing. 4526 * 4527 * 11 - Skip this chunk and continue processing, but report in an ERROR 4528 * Chunk using the 'Unrecognized Chunk Type' cause of error. 4529 * 4530 * The return value is the disposition of the chunk. 4531 */ 4532 enum sctp_disposition sctp_sf_unk_chunk(struct net *net, 4533 const struct sctp_endpoint *ep, 4534 const struct sctp_association *asoc, 4535 const union sctp_subtype type, 4536 void *arg, 4537 struct sctp_cmd_seq *commands) 4538 { 4539 struct sctp_chunk *unk_chunk = arg; 4540 struct sctp_chunk *err_chunk; 4541 struct sctp_chunkhdr *hdr; 4542 4543 pr_debug("%s: processing unknown chunk id:%d\n", __func__, type.chunk); 4544 4545 if (!sctp_vtag_verify(unk_chunk, asoc)) 4546 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4547 4548 /* Make sure that the chunk has a valid length. 4549 * Since we don't know the chunk type, we use a general 4550 * chunkhdr structure to make a comparison. 4551 */ 4552 if (!sctp_chunk_length_valid(unk_chunk, sizeof(*hdr))) 4553 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4554 commands); 4555 4556 switch (type.chunk & SCTP_CID_ACTION_MASK) { 4557 case SCTP_CID_ACTION_DISCARD: 4558 /* Discard the packet. */ 4559 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4560 case SCTP_CID_ACTION_DISCARD_ERR: 4561 /* Generate an ERROR chunk as response. */ 4562 hdr = unk_chunk->chunk_hdr; 4563 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4564 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4565 SCTP_PAD4(ntohs(hdr->length)), 4566 0); 4567 if (err_chunk) { 4568 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4569 SCTP_CHUNK(err_chunk)); 4570 } 4571 4572 /* Discard the packet. */ 4573 sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4574 return SCTP_DISPOSITION_CONSUME; 4575 case SCTP_CID_ACTION_SKIP: 4576 /* Skip the chunk. */ 4577 return SCTP_DISPOSITION_DISCARD; 4578 case SCTP_CID_ACTION_SKIP_ERR: 4579 /* Generate an ERROR chunk as response. */ 4580 hdr = unk_chunk->chunk_hdr; 4581 err_chunk = sctp_make_op_error(asoc, unk_chunk, 4582 SCTP_ERROR_UNKNOWN_CHUNK, hdr, 4583 SCTP_PAD4(ntohs(hdr->length)), 4584 0); 4585 if (err_chunk) { 4586 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 4587 SCTP_CHUNK(err_chunk)); 4588 } 4589 /* Skip the chunk. */ 4590 return SCTP_DISPOSITION_CONSUME; 4591 default: 4592 break; 4593 } 4594 4595 return SCTP_DISPOSITION_DISCARD; 4596 } 4597 4598 /* 4599 * Discard the chunk. 4600 * 4601 * Section: 0.2, 5.2.3, 5.2.5, 5.2.6, 6.0, 8.4.6, 8.5.1c, 9.2 4602 * [Too numerous to mention...] 4603 * Verification Tag: No verification needed. 4604 * Inputs 4605 * (endpoint, asoc, chunk) 4606 * 4607 * Outputs 4608 * (asoc, reply_msg, msg_up, timers, counters) 4609 * 4610 * The return value is the disposition of the chunk. 4611 */ 4612 enum sctp_disposition sctp_sf_discard_chunk(struct net *net, 4613 const struct sctp_endpoint *ep, 4614 const struct sctp_association *asoc, 4615 const union sctp_subtype type, 4616 void *arg, 4617 struct sctp_cmd_seq *commands) 4618 { 4619 struct sctp_chunk *chunk = arg; 4620 4621 if (asoc && !sctp_vtag_verify(chunk, asoc)) 4622 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4623 4624 /* Make sure that the chunk has a valid length. 4625 * Since we don't know the chunk type, we use a general 4626 * chunkhdr structure to make a comparison. 4627 */ 4628 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 4629 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4630 commands); 4631 4632 pr_debug("%s: chunk:%d is discarded\n", __func__, type.chunk); 4633 4634 return SCTP_DISPOSITION_DISCARD; 4635 } 4636 4637 /* 4638 * Discard the whole packet. 4639 * 4640 * Section: 8.4 2) 4641 * 4642 * 2) If the OOTB packet contains an ABORT chunk, the receiver MUST 4643 * silently discard the OOTB packet and take no further action. 4644 * 4645 * Verification Tag: No verification necessary 4646 * 4647 * Inputs 4648 * (endpoint, asoc, chunk) 4649 * 4650 * Outputs 4651 * (asoc, reply_msg, msg_up, timers, counters) 4652 * 4653 * The return value is the disposition of the chunk. 4654 */ 4655 enum sctp_disposition sctp_sf_pdiscard(struct net *net, 4656 const struct sctp_endpoint *ep, 4657 const struct sctp_association *asoc, 4658 const union sctp_subtype type, 4659 void *arg, struct sctp_cmd_seq *commands) 4660 { 4661 SCTP_INC_STATS(net, SCTP_MIB_IN_PKT_DISCARDS); 4662 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 4663 4664 return SCTP_DISPOSITION_CONSUME; 4665 } 4666 4667 4668 /* 4669 * The other end is violating protocol. 4670 * 4671 * Section: Not specified 4672 * Verification Tag: Not specified 4673 * Inputs 4674 * (endpoint, asoc, chunk) 4675 * 4676 * Outputs 4677 * (asoc, reply_msg, msg_up, timers, counters) 4678 * 4679 * We simply tag the chunk as a violation. The state machine will log 4680 * the violation and continue. 4681 */ 4682 enum sctp_disposition sctp_sf_violation(struct net *net, 4683 const struct sctp_endpoint *ep, 4684 const struct sctp_association *asoc, 4685 const union sctp_subtype type, 4686 void *arg, 4687 struct sctp_cmd_seq *commands) 4688 { 4689 struct sctp_chunk *chunk = arg; 4690 4691 if (!sctp_vtag_verify(chunk, asoc)) 4692 return sctp_sf_pdiscard(net, ep, asoc, type, arg, commands); 4693 4694 /* Make sure that the chunk has a valid length. */ 4695 if (!sctp_chunk_length_valid(chunk, sizeof(struct sctp_chunkhdr))) 4696 return sctp_sf_violation_chunklen(net, ep, asoc, type, arg, 4697 commands); 4698 4699 return SCTP_DISPOSITION_VIOLATION; 4700 } 4701 4702 /* 4703 * Common function to handle a protocol violation. 4704 */ 4705 static enum sctp_disposition sctp_sf_abort_violation( 4706 struct net *net, 4707 const struct sctp_endpoint *ep, 4708 const struct sctp_association *asoc, 4709 void *arg, 4710 struct sctp_cmd_seq *commands, 4711 const __u8 *payload, 4712 const size_t paylen) 4713 { 4714 struct sctp_packet *packet = NULL; 4715 struct sctp_chunk *chunk = arg; 4716 struct sctp_chunk *abort = NULL; 4717 4718 /* SCTP-AUTH, Section 6.3: 4719 * It should be noted that if the receiver wants to tear 4720 * down an association in an authenticated way only, the 4721 * handling of malformed packets should not result in 4722 * tearing down the association. 4723 * 4724 * This means that if we only want to abort associations 4725 * in an authenticated way (i.e AUTH+ABORT), then we 4726 * can't destroy this association just because the packet 4727 * was malformed. 4728 */ 4729 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4730 goto discard; 4731 4732 /* Make the abort chunk. */ 4733 abort = sctp_make_abort_violation(asoc, chunk, payload, paylen); 4734 if (!abort) 4735 goto nomem; 4736 4737 if (asoc) { 4738 /* Treat INIT-ACK as a special case during COOKIE-WAIT. */ 4739 if (chunk->chunk_hdr->type == SCTP_CID_INIT_ACK && 4740 !asoc->peer.i.init_tag) { 4741 struct sctp_initack_chunk *initack; 4742 4743 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr; 4744 if (!sctp_chunk_length_valid(chunk, sizeof(*initack))) 4745 abort->chunk_hdr->flags |= SCTP_CHUNK_FLAG_T; 4746 else { 4747 unsigned int inittag; 4748 4749 inittag = ntohl(initack->init_hdr.init_tag); 4750 sctp_add_cmd_sf(commands, SCTP_CMD_UPDATE_INITTAG, 4751 SCTP_U32(inittag)); 4752 } 4753 } 4754 4755 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4756 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4757 4758 if (asoc->state <= SCTP_STATE_COOKIE_ECHOED) { 4759 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 4760 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 4761 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4762 SCTP_ERROR(ECONNREFUSED)); 4763 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 4764 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4765 } else { 4766 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4767 SCTP_ERROR(ECONNABORTED)); 4768 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4769 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4770 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4771 } 4772 } else { 4773 packet = sctp_ootb_pkt_new(net, asoc, chunk); 4774 4775 if (!packet) 4776 goto nomem_pkt; 4777 4778 if (sctp_test_T_bit(abort)) 4779 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 4780 4781 abort->skb->sk = ep->base.sk; 4782 4783 sctp_packet_append_chunk(packet, abort); 4784 4785 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 4786 SCTP_PACKET(packet)); 4787 4788 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4789 } 4790 4791 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4792 4793 discard: 4794 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4795 return SCTP_DISPOSITION_ABORT; 4796 4797 nomem_pkt: 4798 sctp_chunk_free(abort); 4799 nomem: 4800 return SCTP_DISPOSITION_NOMEM; 4801 } 4802 4803 /* 4804 * Handle a protocol violation when the chunk length is invalid. 4805 * "Invalid" length is identified as smaller than the minimal length a 4806 * given chunk can be. For example, a SACK chunk has invalid length 4807 * if its length is set to be smaller than the size of struct sctp_sack_chunk. 4808 * 4809 * We inform the other end by sending an ABORT with a Protocol Violation 4810 * error code. 4811 * 4812 * Section: Not specified 4813 * Verification Tag: Nothing to do 4814 * Inputs 4815 * (endpoint, asoc, chunk) 4816 * 4817 * Outputs 4818 * (reply_msg, msg_up, counters) 4819 * 4820 * Generate an ABORT chunk and terminate the association. 4821 */ 4822 static enum sctp_disposition sctp_sf_violation_chunklen( 4823 struct net *net, 4824 const struct sctp_endpoint *ep, 4825 const struct sctp_association *asoc, 4826 const union sctp_subtype type, 4827 void *arg, 4828 struct sctp_cmd_seq *commands) 4829 { 4830 static const char err_str[] = "The following chunk had invalid length:"; 4831 4832 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4833 sizeof(err_str)); 4834 } 4835 4836 /* 4837 * Handle a protocol violation when the parameter length is invalid. 4838 * If the length is smaller than the minimum length of a given parameter, 4839 * or accumulated length in multi parameters exceeds the end of the chunk, 4840 * the length is considered as invalid. 4841 */ 4842 static enum sctp_disposition sctp_sf_violation_paramlen( 4843 struct net *net, 4844 const struct sctp_endpoint *ep, 4845 const struct sctp_association *asoc, 4846 const union sctp_subtype type, 4847 void *arg, void *ext, 4848 struct sctp_cmd_seq *commands) 4849 { 4850 struct sctp_paramhdr *param = ext; 4851 struct sctp_chunk *abort = NULL; 4852 struct sctp_chunk *chunk = arg; 4853 4854 if (sctp_auth_recv_cid(SCTP_CID_ABORT, asoc)) 4855 goto discard; 4856 4857 /* Make the abort chunk. */ 4858 abort = sctp_make_violation_paramlen(asoc, chunk, param); 4859 if (!abort) 4860 goto nomem; 4861 4862 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 4863 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 4864 4865 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 4866 SCTP_ERROR(ECONNABORTED)); 4867 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 4868 SCTP_PERR(SCTP_ERROR_PROTO_VIOLATION)); 4869 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 4870 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 4871 4872 discard: 4873 sctp_sf_pdiscard(net, ep, asoc, SCTP_ST_CHUNK(0), arg, commands); 4874 return SCTP_DISPOSITION_ABORT; 4875 nomem: 4876 return SCTP_DISPOSITION_NOMEM; 4877 } 4878 4879 /* Handle a protocol violation when the peer trying to advance the 4880 * cumulative tsn ack to a point beyond the max tsn currently sent. 4881 * 4882 * We inform the other end by sending an ABORT with a Protocol Violation 4883 * error code. 4884 */ 4885 static enum sctp_disposition sctp_sf_violation_ctsn( 4886 struct net *net, 4887 const struct sctp_endpoint *ep, 4888 const struct sctp_association *asoc, 4889 const union sctp_subtype type, 4890 void *arg, 4891 struct sctp_cmd_seq *commands) 4892 { 4893 static const char err_str[] = "The cumulative tsn ack beyond the max tsn currently sent:"; 4894 4895 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4896 sizeof(err_str)); 4897 } 4898 4899 /* Handle protocol violation of an invalid chunk bundling. For example, 4900 * when we have an association and we receive bundled INIT-ACK, or 4901 * SHUTDOWN-COMPLETE, our peer is clearly violating the "MUST NOT bundle" 4902 * statement from the specs. Additionally, there might be an attacker 4903 * on the path and we may not want to continue this communication. 4904 */ 4905 static enum sctp_disposition sctp_sf_violation_chunk( 4906 struct net *net, 4907 const struct sctp_endpoint *ep, 4908 const struct sctp_association *asoc, 4909 const union sctp_subtype type, 4910 void *arg, 4911 struct sctp_cmd_seq *commands) 4912 { 4913 static const char err_str[] = "The following chunk violates protocol:"; 4914 4915 return sctp_sf_abort_violation(net, ep, asoc, arg, commands, err_str, 4916 sizeof(err_str)); 4917 } 4918 /*************************************************************************** 4919 * These are the state functions for handling primitive (Section 10) events. 4920 ***************************************************************************/ 4921 /* 4922 * sctp_sf_do_prm_asoc 4923 * 4924 * Section: 10.1 ULP-to-SCTP 4925 * B) Associate 4926 * 4927 * Format: ASSOCIATE(local SCTP instance name, destination transport addr, 4928 * outbound stream count) 4929 * -> association id [,destination transport addr list] [,outbound stream 4930 * count] 4931 * 4932 * This primitive allows the upper layer to initiate an association to a 4933 * specific peer endpoint. 4934 * 4935 * The peer endpoint shall be specified by one of the transport addresses 4936 * which defines the endpoint (see Section 1.4). If the local SCTP 4937 * instance has not been initialized, the ASSOCIATE is considered an 4938 * error. 4939 * [This is not relevant for the kernel implementation since we do all 4940 * initialization at boot time. It we hadn't initialized we wouldn't 4941 * get anywhere near this code.] 4942 * 4943 * An association id, which is a local handle to the SCTP association, 4944 * will be returned on successful establishment of the association. If 4945 * SCTP is not able to open an SCTP association with the peer endpoint, 4946 * an error is returned. 4947 * [In the kernel implementation, the struct sctp_association needs to 4948 * be created BEFORE causing this primitive to run.] 4949 * 4950 * Other association parameters may be returned, including the 4951 * complete destination transport addresses of the peer as well as the 4952 * outbound stream count of the local endpoint. One of the transport 4953 * address from the returned destination addresses will be selected by 4954 * the local endpoint as default primary path for sending SCTP packets 4955 * to this peer. The returned "destination transport addr list" can 4956 * be used by the ULP to change the default primary path or to force 4957 * sending a packet to a specific transport address. [All of this 4958 * stuff happens when the INIT ACK arrives. This is a NON-BLOCKING 4959 * function.] 4960 * 4961 * Mandatory attributes: 4962 * 4963 * o local SCTP instance name - obtained from the INITIALIZE operation. 4964 * [This is the argument asoc.] 4965 * o destination transport addr - specified as one of the transport 4966 * addresses of the peer endpoint with which the association is to be 4967 * established. 4968 * [This is asoc->peer.active_path.] 4969 * o outbound stream count - the number of outbound streams the ULP 4970 * would like to open towards this peer endpoint. 4971 * [BUG: This is not currently implemented.] 4972 * Optional attributes: 4973 * 4974 * None. 4975 * 4976 * The return value is a disposition. 4977 */ 4978 enum sctp_disposition sctp_sf_do_prm_asoc(struct net *net, 4979 const struct sctp_endpoint *ep, 4980 const struct sctp_association *asoc, 4981 const union sctp_subtype type, 4982 void *arg, 4983 struct sctp_cmd_seq *commands) 4984 { 4985 struct sctp_association *my_asoc; 4986 struct sctp_chunk *repl; 4987 4988 /* The comment below says that we enter COOKIE-WAIT AFTER 4989 * sending the INIT, but that doesn't actually work in our 4990 * implementation... 4991 */ 4992 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 4993 SCTP_STATE(SCTP_STATE_COOKIE_WAIT)); 4994 4995 /* RFC 2960 5.1 Normal Establishment of an Association 4996 * 4997 * A) "A" first sends an INIT chunk to "Z". In the INIT, "A" 4998 * must provide its Verification Tag (Tag_A) in the Initiate 4999 * Tag field. Tag_A SHOULD be a random number in the range of 5000 * 1 to 4294967295 (see 5.3.1 for Tag value selection). ... 5001 */ 5002 5003 repl = sctp_make_init(asoc, &asoc->base.bind_addr, GFP_ATOMIC, 0); 5004 if (!repl) 5005 goto nomem; 5006 5007 /* Choose transport for INIT. */ 5008 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5009 SCTP_CHUNK(repl)); 5010 5011 /* Cast away the const modifier, as we want to just 5012 * rerun it through as a sideffect. 5013 */ 5014 my_asoc = (struct sctp_association *)asoc; 5015 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_ASOC, SCTP_ASOC(my_asoc)); 5016 5017 /* After sending the INIT, "A" starts the T1-init timer and 5018 * enters the COOKIE-WAIT state. 5019 */ 5020 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5021 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5022 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5023 return SCTP_DISPOSITION_CONSUME; 5024 5025 nomem: 5026 return SCTP_DISPOSITION_NOMEM; 5027 } 5028 5029 /* 5030 * Process the SEND primitive. 5031 * 5032 * Section: 10.1 ULP-to-SCTP 5033 * E) Send 5034 * 5035 * Format: SEND(association id, buffer address, byte count [,context] 5036 * [,stream id] [,life time] [,destination transport address] 5037 * [,unorder flag] [,no-bundle flag] [,payload protocol-id] ) 5038 * -> result 5039 * 5040 * This is the main method to send user data via SCTP. 5041 * 5042 * Mandatory attributes: 5043 * 5044 * o association id - local handle to the SCTP association 5045 * 5046 * o buffer address - the location where the user message to be 5047 * transmitted is stored; 5048 * 5049 * o byte count - The size of the user data in number of bytes; 5050 * 5051 * Optional attributes: 5052 * 5053 * o context - an optional 32 bit integer that will be carried in the 5054 * sending failure notification to the ULP if the transportation of 5055 * this User Message fails. 5056 * 5057 * o stream id - to indicate which stream to send the data on. If not 5058 * specified, stream 0 will be used. 5059 * 5060 * o life time - specifies the life time of the user data. The user data 5061 * will not be sent by SCTP after the life time expires. This 5062 * parameter can be used to avoid efforts to transmit stale 5063 * user messages. SCTP notifies the ULP if the data cannot be 5064 * initiated to transport (i.e. sent to the destination via SCTP's 5065 * send primitive) within the life time variable. However, the 5066 * user data will be transmitted if SCTP has attempted to transmit a 5067 * chunk before the life time expired. 5068 * 5069 * o destination transport address - specified as one of the destination 5070 * transport addresses of the peer endpoint to which this packet 5071 * should be sent. Whenever possible, SCTP should use this destination 5072 * transport address for sending the packets, instead of the current 5073 * primary path. 5074 * 5075 * o unorder flag - this flag, if present, indicates that the user 5076 * would like the data delivered in an unordered fashion to the peer 5077 * (i.e., the U flag is set to 1 on all DATA chunks carrying this 5078 * message). 5079 * 5080 * o no-bundle flag - instructs SCTP not to bundle this user data with 5081 * other outbound DATA chunks. SCTP MAY still bundle even when 5082 * this flag is present, when faced with network congestion. 5083 * 5084 * o payload protocol-id - A 32 bit unsigned integer that is to be 5085 * passed to the peer indicating the type of payload protocol data 5086 * being transmitted. This value is passed as opaque data by SCTP. 5087 * 5088 * The return value is the disposition. 5089 */ 5090 enum sctp_disposition sctp_sf_do_prm_send(struct net *net, 5091 const struct sctp_endpoint *ep, 5092 const struct sctp_association *asoc, 5093 const union sctp_subtype type, 5094 void *arg, 5095 struct sctp_cmd_seq *commands) 5096 { 5097 struct sctp_datamsg *msg = arg; 5098 5099 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_MSG, SCTP_DATAMSG(msg)); 5100 return SCTP_DISPOSITION_CONSUME; 5101 } 5102 5103 /* 5104 * Process the SHUTDOWN primitive. 5105 * 5106 * Section: 10.1: 5107 * C) Shutdown 5108 * 5109 * Format: SHUTDOWN(association id) 5110 * -> result 5111 * 5112 * Gracefully closes an association. Any locally queued user data 5113 * will be delivered to the peer. The association will be terminated only 5114 * after the peer acknowledges all the SCTP packets sent. A success code 5115 * will be returned on successful termination of the association. If 5116 * attempting to terminate the association results in a failure, an error 5117 * code shall be returned. 5118 * 5119 * Mandatory attributes: 5120 * 5121 * o association id - local handle to the SCTP association 5122 * 5123 * Optional attributes: 5124 * 5125 * None. 5126 * 5127 * The return value is the disposition. 5128 */ 5129 enum sctp_disposition sctp_sf_do_9_2_prm_shutdown( 5130 struct net *net, 5131 const struct sctp_endpoint *ep, 5132 const struct sctp_association *asoc, 5133 const union sctp_subtype type, 5134 void *arg, 5135 struct sctp_cmd_seq *commands) 5136 { 5137 enum sctp_disposition disposition; 5138 5139 /* From 9.2 Shutdown of an Association 5140 * Upon receipt of the SHUTDOWN primitive from its upper 5141 * layer, the endpoint enters SHUTDOWN-PENDING state and 5142 * remains there until all outstanding data has been 5143 * acknowledged by its peer. The endpoint accepts no new data 5144 * from its upper layer, but retransmits data to the far end 5145 * if necessary to fill gaps. 5146 */ 5147 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5148 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 5149 5150 disposition = SCTP_DISPOSITION_CONSUME; 5151 if (sctp_outq_is_empty(&asoc->outqueue)) { 5152 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 5153 arg, commands); 5154 } 5155 5156 return disposition; 5157 } 5158 5159 /* 5160 * Process the ABORT primitive. 5161 * 5162 * Section: 10.1: 5163 * C) Abort 5164 * 5165 * Format: Abort(association id [, cause code]) 5166 * -> result 5167 * 5168 * Ungracefully closes an association. Any locally queued user data 5169 * will be discarded and an ABORT chunk is sent to the peer. A success code 5170 * will be returned on successful abortion of the association. If 5171 * attempting to abort the association results in a failure, an error 5172 * code shall be returned. 5173 * 5174 * Mandatory attributes: 5175 * 5176 * o association id - local handle to the SCTP association 5177 * 5178 * Optional attributes: 5179 * 5180 * o cause code - reason of the abort to be passed to the peer 5181 * 5182 * None. 5183 * 5184 * The return value is the disposition. 5185 */ 5186 enum sctp_disposition sctp_sf_do_9_1_prm_abort( 5187 struct net *net, 5188 const struct sctp_endpoint *ep, 5189 const struct sctp_association *asoc, 5190 const union sctp_subtype type, 5191 void *arg, 5192 struct sctp_cmd_seq *commands) 5193 { 5194 /* From 9.1 Abort of an Association 5195 * Upon receipt of the ABORT primitive from its upper 5196 * layer, the endpoint enters CLOSED state and 5197 * discard all outstanding data has been 5198 * acknowledged by its peer. The endpoint accepts no new data 5199 * from its upper layer, but retransmits data to the far end 5200 * if necessary to fill gaps. 5201 */ 5202 struct sctp_chunk *abort = arg; 5203 5204 if (abort) 5205 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 5206 5207 /* Even if we can't send the ABORT due to low memory delete the 5208 * TCB. This is a departure from our typical NOMEM handling. 5209 */ 5210 5211 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5212 SCTP_ERROR(ECONNABORTED)); 5213 /* Delete the established association. */ 5214 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5215 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 5216 5217 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5218 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5219 5220 return SCTP_DISPOSITION_ABORT; 5221 } 5222 5223 /* We tried an illegal operation on an association which is closed. */ 5224 enum sctp_disposition sctp_sf_error_closed(struct net *net, 5225 const struct sctp_endpoint *ep, 5226 const struct sctp_association *asoc, 5227 const union sctp_subtype type, 5228 void *arg, 5229 struct sctp_cmd_seq *commands) 5230 { 5231 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, SCTP_ERROR(-EINVAL)); 5232 return SCTP_DISPOSITION_CONSUME; 5233 } 5234 5235 /* We tried an illegal operation on an association which is shutting 5236 * down. 5237 */ 5238 enum sctp_disposition sctp_sf_error_shutdown( 5239 struct net *net, 5240 const struct sctp_endpoint *ep, 5241 const struct sctp_association *asoc, 5242 const union sctp_subtype type, 5243 void *arg, 5244 struct sctp_cmd_seq *commands) 5245 { 5246 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_ERROR, 5247 SCTP_ERROR(-ESHUTDOWN)); 5248 return SCTP_DISPOSITION_CONSUME; 5249 } 5250 5251 /* 5252 * sctp_cookie_wait_prm_shutdown 5253 * 5254 * Section: 4 Note: 2 5255 * Verification Tag: 5256 * Inputs 5257 * (endpoint, asoc) 5258 * 5259 * The RFC does not explicitly address this issue, but is the route through the 5260 * state table when someone issues a shutdown while in COOKIE_WAIT state. 5261 * 5262 * Outputs 5263 * (timers) 5264 */ 5265 enum sctp_disposition sctp_sf_cookie_wait_prm_shutdown( 5266 struct net *net, 5267 const struct sctp_endpoint *ep, 5268 const struct sctp_association *asoc, 5269 const union sctp_subtype type, 5270 void *arg, 5271 struct sctp_cmd_seq *commands) 5272 { 5273 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5274 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5275 5276 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5277 SCTP_STATE(SCTP_STATE_CLOSED)); 5278 5279 SCTP_INC_STATS(net, SCTP_MIB_SHUTDOWNS); 5280 5281 sctp_add_cmd_sf(commands, SCTP_CMD_DELETE_TCB, SCTP_NULL()); 5282 5283 return SCTP_DISPOSITION_DELETE_TCB; 5284 } 5285 5286 /* 5287 * sctp_cookie_echoed_prm_shutdown 5288 * 5289 * Section: 4 Note: 2 5290 * Verification Tag: 5291 * Inputs 5292 * (endpoint, asoc) 5293 * 5294 * The RFC does not explicitly address this issue, but is the route through the 5295 * state table when someone issues a shutdown while in COOKIE_ECHOED state. 5296 * 5297 * Outputs 5298 * (timers) 5299 */ 5300 enum sctp_disposition sctp_sf_cookie_echoed_prm_shutdown( 5301 struct net *net, 5302 const struct sctp_endpoint *ep, 5303 const struct sctp_association *asoc, 5304 const union sctp_subtype type, 5305 void *arg, 5306 struct sctp_cmd_seq *commands) 5307 { 5308 /* There is a single T1 timer, so we should be able to use 5309 * common function with the COOKIE-WAIT state. 5310 */ 5311 return sctp_sf_cookie_wait_prm_shutdown(net, ep, asoc, type, arg, commands); 5312 } 5313 5314 /* 5315 * sctp_sf_cookie_wait_prm_abort 5316 * 5317 * Section: 4 Note: 2 5318 * Verification Tag: 5319 * Inputs 5320 * (endpoint, asoc) 5321 * 5322 * The RFC does not explicitly address this issue, but is the route through the 5323 * state table when someone issues an abort while in COOKIE_WAIT state. 5324 * 5325 * Outputs 5326 * (timers) 5327 */ 5328 enum sctp_disposition sctp_sf_cookie_wait_prm_abort( 5329 struct net *net, 5330 const struct sctp_endpoint *ep, 5331 const struct sctp_association *asoc, 5332 const union sctp_subtype type, 5333 void *arg, 5334 struct sctp_cmd_seq *commands) 5335 { 5336 struct sctp_chunk *abort = arg; 5337 5338 /* Stop T1-init timer */ 5339 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5340 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5341 5342 if (abort) 5343 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(abort)); 5344 5345 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5346 SCTP_STATE(SCTP_STATE_CLOSED)); 5347 5348 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5349 5350 /* Even if we can't send the ABORT due to low memory delete the 5351 * TCB. This is a departure from our typical NOMEM handling. 5352 */ 5353 5354 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5355 SCTP_ERROR(ECONNREFUSED)); 5356 /* Delete the established association. */ 5357 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5358 SCTP_PERR(SCTP_ERROR_USER_ABORT)); 5359 5360 return SCTP_DISPOSITION_ABORT; 5361 } 5362 5363 /* 5364 * sctp_sf_cookie_echoed_prm_abort 5365 * 5366 * Section: 4 Note: 3 5367 * Verification Tag: 5368 * Inputs 5369 * (endpoint, asoc) 5370 * 5371 * The RFC does not explcitly address this issue, but is the route through the 5372 * state table when someone issues an abort while in COOKIE_ECHOED state. 5373 * 5374 * Outputs 5375 * (timers) 5376 */ 5377 enum sctp_disposition sctp_sf_cookie_echoed_prm_abort( 5378 struct net *net, 5379 const struct sctp_endpoint *ep, 5380 const struct sctp_association *asoc, 5381 const union sctp_subtype type, 5382 void *arg, 5383 struct sctp_cmd_seq *commands) 5384 { 5385 /* There is a single T1 timer, so we should be able to use 5386 * common function with the COOKIE-WAIT state. 5387 */ 5388 return sctp_sf_cookie_wait_prm_abort(net, ep, asoc, type, arg, commands); 5389 } 5390 5391 /* 5392 * sctp_sf_shutdown_pending_prm_abort 5393 * 5394 * Inputs 5395 * (endpoint, asoc) 5396 * 5397 * The RFC does not explicitly address this issue, but is the route through the 5398 * state table when someone issues an abort while in SHUTDOWN-PENDING state. 5399 * 5400 * Outputs 5401 * (timers) 5402 */ 5403 enum sctp_disposition sctp_sf_shutdown_pending_prm_abort( 5404 struct net *net, 5405 const struct sctp_endpoint *ep, 5406 const struct sctp_association *asoc, 5407 const union sctp_subtype type, 5408 void *arg, 5409 struct sctp_cmd_seq *commands) 5410 { 5411 /* Stop the T5-shutdown guard timer. */ 5412 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5413 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5414 5415 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5416 } 5417 5418 /* 5419 * sctp_sf_shutdown_sent_prm_abort 5420 * 5421 * Inputs 5422 * (endpoint, asoc) 5423 * 5424 * The RFC does not explicitly address this issue, but is the route through the 5425 * state table when someone issues an abort while in SHUTDOWN-SENT state. 5426 * 5427 * Outputs 5428 * (timers) 5429 */ 5430 enum sctp_disposition sctp_sf_shutdown_sent_prm_abort( 5431 struct net *net, 5432 const struct sctp_endpoint *ep, 5433 const struct sctp_association *asoc, 5434 const union sctp_subtype type, 5435 void *arg, 5436 struct sctp_cmd_seq *commands) 5437 { 5438 /* Stop the T2-shutdown timer. */ 5439 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5440 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5441 5442 /* Stop the T5-shutdown guard timer. */ 5443 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5444 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5445 5446 return sctp_sf_do_9_1_prm_abort(net, ep, asoc, type, arg, commands); 5447 } 5448 5449 /* 5450 * sctp_sf_cookie_echoed_prm_abort 5451 * 5452 * Inputs 5453 * (endpoint, asoc) 5454 * 5455 * The RFC does not explcitly address this issue, but is the route through the 5456 * state table when someone issues an abort while in COOKIE_ECHOED state. 5457 * 5458 * Outputs 5459 * (timers) 5460 */ 5461 enum sctp_disposition sctp_sf_shutdown_ack_sent_prm_abort( 5462 struct net *net, 5463 const struct sctp_endpoint *ep, 5464 const struct sctp_association *asoc, 5465 const union sctp_subtype type, 5466 void *arg, 5467 struct sctp_cmd_seq *commands) 5468 { 5469 /* The same T2 timer, so we should be able to use 5470 * common function with the SHUTDOWN-SENT state. 5471 */ 5472 return sctp_sf_shutdown_sent_prm_abort(net, ep, asoc, type, arg, commands); 5473 } 5474 5475 /* 5476 * Process the REQUESTHEARTBEAT primitive 5477 * 5478 * 10.1 ULP-to-SCTP 5479 * J) Request Heartbeat 5480 * 5481 * Format: REQUESTHEARTBEAT(association id, destination transport address) 5482 * 5483 * -> result 5484 * 5485 * Instructs the local endpoint to perform a HeartBeat on the specified 5486 * destination transport address of the given association. The returned 5487 * result should indicate whether the transmission of the HEARTBEAT 5488 * chunk to the destination address is successful. 5489 * 5490 * Mandatory attributes: 5491 * 5492 * o association id - local handle to the SCTP association 5493 * 5494 * o destination transport address - the transport address of the 5495 * association on which a heartbeat should be issued. 5496 */ 5497 enum sctp_disposition sctp_sf_do_prm_requestheartbeat( 5498 struct net *net, 5499 const struct sctp_endpoint *ep, 5500 const struct sctp_association *asoc, 5501 const union sctp_subtype type, 5502 void *arg, 5503 struct sctp_cmd_seq *commands) 5504 { 5505 if (SCTP_DISPOSITION_NOMEM == sctp_sf_heartbeat(ep, asoc, type, 5506 (struct sctp_transport *)arg, commands)) 5507 return SCTP_DISPOSITION_NOMEM; 5508 5509 /* 5510 * RFC 2960 (bis), section 8.3 5511 * 5512 * D) Request an on-demand HEARTBEAT on a specific destination 5513 * transport address of a given association. 5514 * 5515 * The endpoint should increment the respective error counter of 5516 * the destination transport address each time a HEARTBEAT is sent 5517 * to that address and not acknowledged within one RTO. 5518 * 5519 */ 5520 sctp_add_cmd_sf(commands, SCTP_CMD_TRANSPORT_HB_SENT, 5521 SCTP_TRANSPORT(arg)); 5522 return SCTP_DISPOSITION_CONSUME; 5523 } 5524 5525 /* 5526 * ADDIP Section 4.1 ASCONF Chunk Procedures 5527 * When an endpoint has an ASCONF signaled change to be sent to the 5528 * remote endpoint it should do A1 to A9 5529 */ 5530 enum sctp_disposition sctp_sf_do_prm_asconf(struct net *net, 5531 const struct sctp_endpoint *ep, 5532 const struct sctp_association *asoc, 5533 const union sctp_subtype type, 5534 void *arg, 5535 struct sctp_cmd_seq *commands) 5536 { 5537 struct sctp_chunk *chunk = arg; 5538 5539 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 5540 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5541 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 5542 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5543 return SCTP_DISPOSITION_CONSUME; 5544 } 5545 5546 /* RE-CONFIG Section 5.1 RECONF Chunk Procedures */ 5547 enum sctp_disposition sctp_sf_do_prm_reconf(struct net *net, 5548 const struct sctp_endpoint *ep, 5549 const struct sctp_association *asoc, 5550 const union sctp_subtype type, 5551 void *arg, 5552 struct sctp_cmd_seq *commands) 5553 { 5554 struct sctp_chunk *chunk = arg; 5555 5556 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(chunk)); 5557 return SCTP_DISPOSITION_CONSUME; 5558 } 5559 5560 /* 5561 * Ignore the primitive event 5562 * 5563 * The return value is the disposition of the primitive. 5564 */ 5565 enum sctp_disposition sctp_sf_ignore_primitive( 5566 struct net *net, 5567 const struct sctp_endpoint *ep, 5568 const struct sctp_association *asoc, 5569 const union sctp_subtype type, 5570 void *arg, 5571 struct sctp_cmd_seq *commands) 5572 { 5573 pr_debug("%s: primitive type:%d is ignored\n", __func__, 5574 type.primitive); 5575 5576 return SCTP_DISPOSITION_DISCARD; 5577 } 5578 5579 /*************************************************************************** 5580 * These are the state functions for the OTHER events. 5581 ***************************************************************************/ 5582 5583 /* 5584 * When the SCTP stack has no more user data to send or retransmit, this 5585 * notification is given to the user. Also, at the time when a user app 5586 * subscribes to this event, if there is no data to be sent or 5587 * retransmit, the stack will immediately send up this notification. 5588 */ 5589 enum sctp_disposition sctp_sf_do_no_pending_tsn( 5590 struct net *net, 5591 const struct sctp_endpoint *ep, 5592 const struct sctp_association *asoc, 5593 const union sctp_subtype type, 5594 void *arg, 5595 struct sctp_cmd_seq *commands) 5596 { 5597 struct sctp_ulpevent *event; 5598 5599 event = sctp_ulpevent_make_sender_dry_event(asoc, GFP_ATOMIC); 5600 if (!event) 5601 return SCTP_DISPOSITION_NOMEM; 5602 5603 sctp_add_cmd_sf(commands, SCTP_CMD_EVENT_ULP, SCTP_ULPEVENT(event)); 5604 5605 return SCTP_DISPOSITION_CONSUME; 5606 } 5607 5608 /* 5609 * Start the shutdown negotiation. 5610 * 5611 * From Section 9.2: 5612 * Once all its outstanding data has been acknowledged, the endpoint 5613 * shall send a SHUTDOWN chunk to its peer including in the Cumulative 5614 * TSN Ack field the last sequential TSN it has received from the peer. 5615 * It shall then start the T2-shutdown timer and enter the SHUTDOWN-SENT 5616 * state. If the timer expires, the endpoint must re-send the SHUTDOWN 5617 * with the updated last sequential TSN received from its peer. 5618 * 5619 * The return value is the disposition. 5620 */ 5621 enum sctp_disposition sctp_sf_do_9_2_start_shutdown( 5622 struct net *net, 5623 const struct sctp_endpoint *ep, 5624 const struct sctp_association *asoc, 5625 const union sctp_subtype type, 5626 void *arg, 5627 struct sctp_cmd_seq *commands) 5628 { 5629 struct sctp_chunk *reply; 5630 5631 /* Once all its outstanding data has been acknowledged, the 5632 * endpoint shall send a SHUTDOWN chunk to its peer including 5633 * in the Cumulative TSN Ack field the last sequential TSN it 5634 * has received from the peer. 5635 */ 5636 reply = sctp_make_shutdown(asoc, arg); 5637 if (!reply) 5638 goto nomem; 5639 5640 /* Set the transport for the SHUTDOWN chunk and the timeout for the 5641 * T2-shutdown timer. 5642 */ 5643 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5644 5645 /* It shall then start the T2-shutdown timer */ 5646 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START, 5647 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5648 5649 /* RFC 4960 Section 9.2 5650 * The sender of the SHUTDOWN MAY also start an overall guard timer 5651 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 5652 */ 5653 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5654 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5655 5656 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5657 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5658 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5659 5660 /* and enter the SHUTDOWN-SENT state. */ 5661 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5662 SCTP_STATE(SCTP_STATE_SHUTDOWN_SENT)); 5663 5664 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5665 * 5666 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5667 * or SHUTDOWN-ACK. 5668 */ 5669 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5670 5671 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5672 5673 return SCTP_DISPOSITION_CONSUME; 5674 5675 nomem: 5676 return SCTP_DISPOSITION_NOMEM; 5677 } 5678 5679 /* 5680 * Generate a SHUTDOWN ACK now that everything is SACK'd. 5681 * 5682 * From Section 9.2: 5683 * 5684 * If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5685 * shall send a SHUTDOWN ACK and start a T2-shutdown timer of its own, 5686 * entering the SHUTDOWN-ACK-SENT state. If the timer expires, the 5687 * endpoint must re-send the SHUTDOWN ACK. 5688 * 5689 * The return value is the disposition. 5690 */ 5691 enum sctp_disposition sctp_sf_do_9_2_shutdown_ack( 5692 struct net *net, 5693 const struct sctp_endpoint *ep, 5694 const struct sctp_association *asoc, 5695 const union sctp_subtype type, 5696 void *arg, 5697 struct sctp_cmd_seq *commands) 5698 { 5699 struct sctp_chunk *chunk = arg; 5700 struct sctp_chunk *reply; 5701 5702 /* There are 2 ways of getting here: 5703 * 1) called in response to a SHUTDOWN chunk 5704 * 2) called when SCTP_EVENT_NO_PENDING_TSN event is issued. 5705 * 5706 * For the case (2), the arg parameter is set to NULL. We need 5707 * to check that we have a chunk before accessing it's fields. 5708 */ 5709 if (chunk) { 5710 if (!sctp_vtag_verify(chunk, asoc)) 5711 return sctp_sf_pdiscard(net, ep, asoc, type, arg, 5712 commands); 5713 5714 /* Make sure that the SHUTDOWN chunk has a valid length. */ 5715 if (!sctp_chunk_length_valid( 5716 chunk, sizeof(struct sctp_shutdown_chunk))) 5717 return sctp_sf_violation_chunklen(net, ep, asoc, type, 5718 arg, commands); 5719 } 5720 5721 /* If it has no more outstanding DATA chunks, the SHUTDOWN receiver 5722 * shall send a SHUTDOWN ACK ... 5723 */ 5724 reply = sctp_make_shutdown_ack(asoc, chunk); 5725 if (!reply) 5726 goto nomem; 5727 5728 /* Set the transport for the SHUTDOWN ACK chunk and the timeout for 5729 * the T2-shutdown timer. 5730 */ 5731 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 5732 5733 /* and start/restart a T2-shutdown timer of its own, */ 5734 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 5735 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 5736 5737 if (asoc->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE]) 5738 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 5739 SCTP_TO(SCTP_EVENT_TIMEOUT_AUTOCLOSE)); 5740 5741 /* Enter the SHUTDOWN-ACK-SENT state. */ 5742 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 5743 SCTP_STATE(SCTP_STATE_SHUTDOWN_ACK_SENT)); 5744 5745 /* sctp-implguide 2.10 Issues with Heartbeating and failover 5746 * 5747 * HEARTBEAT ... is discontinued after sending either SHUTDOWN 5748 * or SHUTDOWN-ACK. 5749 */ 5750 sctp_add_cmd_sf(commands, SCTP_CMD_HB_TIMERS_STOP, SCTP_NULL()); 5751 5752 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 5753 5754 return SCTP_DISPOSITION_CONSUME; 5755 5756 nomem: 5757 return SCTP_DISPOSITION_NOMEM; 5758 } 5759 5760 /* 5761 * Ignore the event defined as other 5762 * 5763 * The return value is the disposition of the event. 5764 */ 5765 enum sctp_disposition sctp_sf_ignore_other(struct net *net, 5766 const struct sctp_endpoint *ep, 5767 const struct sctp_association *asoc, 5768 const union sctp_subtype type, 5769 void *arg, 5770 struct sctp_cmd_seq *commands) 5771 { 5772 pr_debug("%s: the event other type:%d is ignored\n", 5773 __func__, type.other); 5774 5775 return SCTP_DISPOSITION_DISCARD; 5776 } 5777 5778 /************************************************************ 5779 * These are the state functions for handling timeout events. 5780 ************************************************************/ 5781 5782 /* 5783 * RTX Timeout 5784 * 5785 * Section: 6.3.3 Handle T3-rtx Expiration 5786 * 5787 * Whenever the retransmission timer T3-rtx expires for a destination 5788 * address, do the following: 5789 * [See below] 5790 * 5791 * The return value is the disposition of the chunk. 5792 */ 5793 enum sctp_disposition sctp_sf_do_6_3_3_rtx(struct net *net, 5794 const struct sctp_endpoint *ep, 5795 const struct sctp_association *asoc, 5796 const union sctp_subtype type, 5797 void *arg, 5798 struct sctp_cmd_seq *commands) 5799 { 5800 struct sctp_transport *transport = arg; 5801 5802 SCTP_INC_STATS(net, SCTP_MIB_T3_RTX_EXPIREDS); 5803 5804 if (asoc->overall_error_count >= asoc->max_retrans) { 5805 if (asoc->peer.zero_window_announced && 5806 asoc->state == SCTP_STATE_SHUTDOWN_PENDING) { 5807 /* 5808 * We are here likely because the receiver had its rwnd 5809 * closed for a while and we have not been able to 5810 * transmit the locally queued data within the maximum 5811 * retransmission attempts limit. Start the T5 5812 * shutdown guard timer to give the receiver one last 5813 * chance and some additional time to recover before 5814 * aborting. 5815 */ 5816 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_START_ONCE, 5817 SCTP_TO(SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD)); 5818 } else { 5819 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5820 SCTP_ERROR(ETIMEDOUT)); 5821 /* CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 5822 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 5823 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5824 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 5825 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 5826 return SCTP_DISPOSITION_DELETE_TCB; 5827 } 5828 } 5829 5830 /* E1) For the destination address for which the timer 5831 * expires, adjust its ssthresh with rules defined in Section 5832 * 7.2.3 and set the cwnd <- MTU. 5833 */ 5834 5835 /* E2) For the destination address for which the timer 5836 * expires, set RTO <- RTO * 2 ("back off the timer"). The 5837 * maximum value discussed in rule C7 above (RTO.max) may be 5838 * used to provide an upper bound to this doubling operation. 5839 */ 5840 5841 /* E3) Determine how many of the earliest (i.e., lowest TSN) 5842 * outstanding DATA chunks for the address for which the 5843 * T3-rtx has expired will fit into a single packet, subject 5844 * to the MTU constraint for the path corresponding to the 5845 * destination transport address to which the retransmission 5846 * is being sent (this may be different from the address for 5847 * which the timer expires [see Section 6.4]). Call this 5848 * value K. Bundle and retransmit those K DATA chunks in a 5849 * single packet to the destination endpoint. 5850 * 5851 * Note: Any DATA chunks that were sent to the address for 5852 * which the T3-rtx timer expired but did not fit in one MTU 5853 * (rule E3 above), should be marked for retransmission and 5854 * sent as soon as cwnd allows (normally when a SACK arrives). 5855 */ 5856 5857 /* Do some failure management (Section 8.2). */ 5858 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, SCTP_TRANSPORT(transport)); 5859 5860 /* NB: Rules E4 and F1 are implicit in R1. */ 5861 sctp_add_cmd_sf(commands, SCTP_CMD_RETRAN, SCTP_TRANSPORT(transport)); 5862 5863 return SCTP_DISPOSITION_CONSUME; 5864 } 5865 5866 /* 5867 * Generate delayed SACK on timeout 5868 * 5869 * Section: 6.2 Acknowledgement on Reception of DATA Chunks 5870 * 5871 * The guidelines on delayed acknowledgement algorithm specified in 5872 * Section 4.2 of [RFC2581] SHOULD be followed. Specifically, an 5873 * acknowledgement SHOULD be generated for at least every second packet 5874 * (not every second DATA chunk) received, and SHOULD be generated 5875 * within 200 ms of the arrival of any unacknowledged DATA chunk. In 5876 * some situations it may be beneficial for an SCTP transmitter to be 5877 * more conservative than the algorithms detailed in this document 5878 * allow. However, an SCTP transmitter MUST NOT be more aggressive than 5879 * the following algorithms allow. 5880 */ 5881 enum sctp_disposition sctp_sf_do_6_2_sack(struct net *net, 5882 const struct sctp_endpoint *ep, 5883 const struct sctp_association *asoc, 5884 const union sctp_subtype type, 5885 void *arg, 5886 struct sctp_cmd_seq *commands) 5887 { 5888 SCTP_INC_STATS(net, SCTP_MIB_DELAY_SACK_EXPIREDS); 5889 sctp_add_cmd_sf(commands, SCTP_CMD_GEN_SACK, SCTP_FORCE()); 5890 return SCTP_DISPOSITION_CONSUME; 5891 } 5892 5893 /* 5894 * sctp_sf_t1_init_timer_expire 5895 * 5896 * Section: 4 Note: 2 5897 * Verification Tag: 5898 * Inputs 5899 * (endpoint, asoc) 5900 * 5901 * RFC 2960 Section 4 Notes 5902 * 2) If the T1-init timer expires, the endpoint MUST retransmit INIT 5903 * and re-start the T1-init timer without changing state. This MUST 5904 * be repeated up to 'Max.Init.Retransmits' times. After that, the 5905 * endpoint MUST abort the initialization process and report the 5906 * error to SCTP user. 5907 * 5908 * Outputs 5909 * (timers, events) 5910 * 5911 */ 5912 enum sctp_disposition sctp_sf_t1_init_timer_expire( 5913 struct net *net, 5914 const struct sctp_endpoint *ep, 5915 const struct sctp_association *asoc, 5916 const union sctp_subtype type, 5917 void *arg, 5918 struct sctp_cmd_seq *commands) 5919 { 5920 int attempts = asoc->init_err_counter + 1; 5921 struct sctp_chunk *repl = NULL; 5922 struct sctp_bind_addr *bp; 5923 5924 pr_debug("%s: timer T1 expired (INIT)\n", __func__); 5925 5926 SCTP_INC_STATS(net, SCTP_MIB_T1_INIT_EXPIREDS); 5927 5928 if (attempts <= asoc->max_init_attempts) { 5929 bp = (struct sctp_bind_addr *) &asoc->base.bind_addr; 5930 repl = sctp_make_init(asoc, bp, GFP_ATOMIC, 0); 5931 if (!repl) 5932 return SCTP_DISPOSITION_NOMEM; 5933 5934 /* Choose transport for INIT. */ 5935 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5936 SCTP_CHUNK(repl)); 5937 5938 /* Issue a sideeffect to do the needed accounting. */ 5939 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_RESTART, 5940 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_INIT)); 5941 5942 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 5943 } else { 5944 pr_debug("%s: giving up on INIT, attempts:%d " 5945 "max_init_attempts:%d\n", __func__, attempts, 5946 asoc->max_init_attempts); 5947 5948 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 5949 SCTP_ERROR(ETIMEDOUT)); 5950 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 5951 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 5952 return SCTP_DISPOSITION_DELETE_TCB; 5953 } 5954 5955 return SCTP_DISPOSITION_CONSUME; 5956 } 5957 5958 /* 5959 * sctp_sf_t1_cookie_timer_expire 5960 * 5961 * Section: 4 Note: 2 5962 * Verification Tag: 5963 * Inputs 5964 * (endpoint, asoc) 5965 * 5966 * RFC 2960 Section 4 Notes 5967 * 3) If the T1-cookie timer expires, the endpoint MUST retransmit 5968 * COOKIE ECHO and re-start the T1-cookie timer without changing 5969 * state. This MUST be repeated up to 'Max.Init.Retransmits' times. 5970 * After that, the endpoint MUST abort the initialization process and 5971 * report the error to SCTP user. 5972 * 5973 * Outputs 5974 * (timers, events) 5975 * 5976 */ 5977 enum sctp_disposition sctp_sf_t1_cookie_timer_expire( 5978 struct net *net, 5979 const struct sctp_endpoint *ep, 5980 const struct sctp_association *asoc, 5981 const union sctp_subtype type, 5982 void *arg, 5983 struct sctp_cmd_seq *commands) 5984 { 5985 int attempts = asoc->init_err_counter + 1; 5986 struct sctp_chunk *repl = NULL; 5987 5988 pr_debug("%s: timer T1 expired (COOKIE-ECHO)\n", __func__); 5989 5990 SCTP_INC_STATS(net, SCTP_MIB_T1_COOKIE_EXPIREDS); 5991 5992 if (attempts <= asoc->max_init_attempts) { 5993 repl = sctp_make_cookie_echo(asoc, NULL); 5994 if (!repl) 5995 return SCTP_DISPOSITION_NOMEM; 5996 5997 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_CHOOSE_TRANSPORT, 5998 SCTP_CHUNK(repl)); 5999 /* Issue a sideeffect to do the needed accounting. */ 6000 sctp_add_cmd_sf(commands, SCTP_CMD_COOKIEECHO_RESTART, 6001 SCTP_TO(SCTP_EVENT_TIMEOUT_T1_COOKIE)); 6002 6003 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(repl)); 6004 } else { 6005 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6006 SCTP_ERROR(ETIMEDOUT)); 6007 sctp_add_cmd_sf(commands, SCTP_CMD_INIT_FAILED, 6008 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6009 return SCTP_DISPOSITION_DELETE_TCB; 6010 } 6011 6012 return SCTP_DISPOSITION_CONSUME; 6013 } 6014 6015 /* RFC2960 9.2 If the timer expires, the endpoint must re-send the SHUTDOWN 6016 * with the updated last sequential TSN received from its peer. 6017 * 6018 * An endpoint should limit the number of retransmission of the 6019 * SHUTDOWN chunk to the protocol parameter 'Association.Max.Retrans'. 6020 * If this threshold is exceeded the endpoint should destroy the TCB and 6021 * MUST report the peer endpoint unreachable to the upper layer (and 6022 * thus the association enters the CLOSED state). The reception of any 6023 * packet from its peer (i.e. as the peer sends all of its queued DATA 6024 * chunks) should clear the endpoint's retransmission count and restart 6025 * the T2-Shutdown timer, giving its peer ample opportunity to transmit 6026 * all of its queued DATA chunks that have not yet been sent. 6027 */ 6028 enum sctp_disposition sctp_sf_t2_timer_expire( 6029 struct net *net, 6030 const struct sctp_endpoint *ep, 6031 const struct sctp_association *asoc, 6032 const union sctp_subtype type, 6033 void *arg, 6034 struct sctp_cmd_seq *commands) 6035 { 6036 struct sctp_chunk *reply = NULL; 6037 6038 pr_debug("%s: timer T2 expired\n", __func__); 6039 6040 SCTP_INC_STATS(net, SCTP_MIB_T2_SHUTDOWN_EXPIREDS); 6041 6042 ((struct sctp_association *)asoc)->shutdown_retries++; 6043 6044 if (asoc->overall_error_count >= asoc->max_retrans) { 6045 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6046 SCTP_ERROR(ETIMEDOUT)); 6047 /* Note: CMD_ASSOC_FAILED calls CMD_DELETE_TCB. */ 6048 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6049 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6050 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6051 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6052 return SCTP_DISPOSITION_DELETE_TCB; 6053 } 6054 6055 switch (asoc->state) { 6056 case SCTP_STATE_SHUTDOWN_SENT: 6057 reply = sctp_make_shutdown(asoc, NULL); 6058 break; 6059 6060 case SCTP_STATE_SHUTDOWN_ACK_SENT: 6061 reply = sctp_make_shutdown_ack(asoc, NULL); 6062 break; 6063 6064 default: 6065 BUG(); 6066 break; 6067 } 6068 6069 if (!reply) 6070 goto nomem; 6071 6072 /* Do some failure management (Section 8.2). 6073 * If we remove the transport an SHUTDOWN was last sent to, don't 6074 * do failure management. 6075 */ 6076 if (asoc->shutdown_last_sent_to) 6077 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 6078 SCTP_TRANSPORT(asoc->shutdown_last_sent_to)); 6079 6080 /* Set the transport for the SHUTDOWN/ACK chunk and the timeout for 6081 * the T2-shutdown timer. 6082 */ 6083 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T2, SCTP_CHUNK(reply)); 6084 6085 /* Restart the T2-shutdown timer. */ 6086 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 6087 SCTP_TO(SCTP_EVENT_TIMEOUT_T2_SHUTDOWN)); 6088 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 6089 return SCTP_DISPOSITION_CONSUME; 6090 6091 nomem: 6092 return SCTP_DISPOSITION_NOMEM; 6093 } 6094 6095 /* 6096 * ADDIP Section 4.1 ASCONF Chunk Procedures 6097 * If the T4 RTO timer expires the endpoint should do B1 to B5 6098 */ 6099 enum sctp_disposition sctp_sf_t4_timer_expire( 6100 struct net *net, 6101 const struct sctp_endpoint *ep, 6102 const struct sctp_association *asoc, 6103 const union sctp_subtype type, 6104 void *arg, 6105 struct sctp_cmd_seq *commands) 6106 { 6107 struct sctp_chunk *chunk = asoc->addip_last_asconf; 6108 struct sctp_transport *transport = chunk->transport; 6109 6110 SCTP_INC_STATS(net, SCTP_MIB_T4_RTO_EXPIREDS); 6111 6112 /* ADDIP 4.1 B1) Increment the error counters and perform path failure 6113 * detection on the appropriate destination address as defined in 6114 * RFC2960 [5] section 8.1 and 8.2. 6115 */ 6116 if (transport) 6117 sctp_add_cmd_sf(commands, SCTP_CMD_STRIKE, 6118 SCTP_TRANSPORT(transport)); 6119 6120 /* Reconfig T4 timer and transport. */ 6121 sctp_add_cmd_sf(commands, SCTP_CMD_SETUP_T4, SCTP_CHUNK(chunk)); 6122 6123 /* ADDIP 4.1 B2) Increment the association error counters and perform 6124 * endpoint failure detection on the association as defined in 6125 * RFC2960 [5] section 8.1 and 8.2. 6126 * association error counter is incremented in SCTP_CMD_STRIKE. 6127 */ 6128 if (asoc->overall_error_count >= asoc->max_retrans) { 6129 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_STOP, 6130 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 6131 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6132 SCTP_ERROR(ETIMEDOUT)); 6133 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6134 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6135 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6136 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6137 return SCTP_DISPOSITION_ABORT; 6138 } 6139 6140 /* ADDIP 4.1 B3) Back-off the destination address RTO value to which 6141 * the ASCONF chunk was sent by doubling the RTO timer value. 6142 * This is done in SCTP_CMD_STRIKE. 6143 */ 6144 6145 /* ADDIP 4.1 B4) Re-transmit the ASCONF Chunk last sent and if possible 6146 * choose an alternate destination address (please refer to RFC2960 6147 * [5] section 6.4.1). An endpoint MUST NOT add new parameters to this 6148 * chunk, it MUST be the same (including its serial number) as the last 6149 * ASCONF sent. 6150 */ 6151 sctp_chunk_hold(asoc->addip_last_asconf); 6152 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6153 SCTP_CHUNK(asoc->addip_last_asconf)); 6154 6155 /* ADDIP 4.1 B5) Restart the T-4 RTO timer. Note that if a different 6156 * destination is selected, then the RTO used will be that of the new 6157 * destination address. 6158 */ 6159 sctp_add_cmd_sf(commands, SCTP_CMD_TIMER_RESTART, 6160 SCTP_TO(SCTP_EVENT_TIMEOUT_T4_RTO)); 6161 6162 return SCTP_DISPOSITION_CONSUME; 6163 } 6164 6165 /* sctpimpguide-05 Section 2.12.2 6166 * The sender of the SHUTDOWN MAY also start an overall guard timer 6167 * 'T5-shutdown-guard' to bound the overall time for shutdown sequence. 6168 * At the expiration of this timer the sender SHOULD abort the association 6169 * by sending an ABORT chunk. 6170 */ 6171 enum sctp_disposition sctp_sf_t5_timer_expire( 6172 struct net *net, 6173 const struct sctp_endpoint *ep, 6174 const struct sctp_association *asoc, 6175 const union sctp_subtype type, 6176 void *arg, 6177 struct sctp_cmd_seq *commands) 6178 { 6179 struct sctp_chunk *reply = NULL; 6180 6181 pr_debug("%s: timer T5 expired\n", __func__); 6182 6183 SCTP_INC_STATS(net, SCTP_MIB_T5_SHUTDOWN_GUARD_EXPIREDS); 6184 6185 reply = sctp_make_abort(asoc, NULL, 0); 6186 if (!reply) 6187 goto nomem; 6188 6189 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, SCTP_CHUNK(reply)); 6190 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6191 SCTP_ERROR(ETIMEDOUT)); 6192 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6193 SCTP_PERR(SCTP_ERROR_NO_ERROR)); 6194 6195 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6196 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6197 6198 return SCTP_DISPOSITION_DELETE_TCB; 6199 nomem: 6200 return SCTP_DISPOSITION_NOMEM; 6201 } 6202 6203 /* Handle expiration of AUTOCLOSE timer. When the autoclose timer expires, 6204 * the association is automatically closed by starting the shutdown process. 6205 * The work that needs to be done is same as when SHUTDOWN is initiated by 6206 * the user. So this routine looks same as sctp_sf_do_9_2_prm_shutdown(). 6207 */ 6208 enum sctp_disposition sctp_sf_autoclose_timer_expire( 6209 struct net *net, 6210 const struct sctp_endpoint *ep, 6211 const struct sctp_association *asoc, 6212 const union sctp_subtype type, 6213 void *arg, 6214 struct sctp_cmd_seq *commands) 6215 { 6216 enum sctp_disposition disposition; 6217 6218 SCTP_INC_STATS(net, SCTP_MIB_AUTOCLOSE_EXPIREDS); 6219 6220 /* From 9.2 Shutdown of an Association 6221 * Upon receipt of the SHUTDOWN primitive from its upper 6222 * layer, the endpoint enters SHUTDOWN-PENDING state and 6223 * remains there until all outstanding data has been 6224 * acknowledged by its peer. The endpoint accepts no new data 6225 * from its upper layer, but retransmits data to the far end 6226 * if necessary to fill gaps. 6227 */ 6228 sctp_add_cmd_sf(commands, SCTP_CMD_NEW_STATE, 6229 SCTP_STATE(SCTP_STATE_SHUTDOWN_PENDING)); 6230 6231 disposition = SCTP_DISPOSITION_CONSUME; 6232 if (sctp_outq_is_empty(&asoc->outqueue)) { 6233 disposition = sctp_sf_do_9_2_start_shutdown(net, ep, asoc, type, 6234 NULL, commands); 6235 } 6236 6237 return disposition; 6238 } 6239 6240 /***************************************************************************** 6241 * These are sa state functions which could apply to all types of events. 6242 ****************************************************************************/ 6243 6244 /* 6245 * This table entry is not implemented. 6246 * 6247 * Inputs 6248 * (endpoint, asoc, chunk) 6249 * 6250 * The return value is the disposition of the chunk. 6251 */ 6252 enum sctp_disposition sctp_sf_not_impl(struct net *net, 6253 const struct sctp_endpoint *ep, 6254 const struct sctp_association *asoc, 6255 const union sctp_subtype type, 6256 void *arg, struct sctp_cmd_seq *commands) 6257 { 6258 return SCTP_DISPOSITION_NOT_IMPL; 6259 } 6260 6261 /* 6262 * This table entry represents a bug. 6263 * 6264 * Inputs 6265 * (endpoint, asoc, chunk) 6266 * 6267 * The return value is the disposition of the chunk. 6268 */ 6269 enum sctp_disposition sctp_sf_bug(struct net *net, 6270 const struct sctp_endpoint *ep, 6271 const struct sctp_association *asoc, 6272 const union sctp_subtype type, 6273 void *arg, struct sctp_cmd_seq *commands) 6274 { 6275 return SCTP_DISPOSITION_BUG; 6276 } 6277 6278 /* 6279 * This table entry represents the firing of a timer in the wrong state. 6280 * Since timer deletion cannot be guaranteed a timer 'may' end up firing 6281 * when the association is in the wrong state. This event should 6282 * be ignored, so as to prevent any rearming of the timer. 6283 * 6284 * Inputs 6285 * (endpoint, asoc, chunk) 6286 * 6287 * The return value is the disposition of the chunk. 6288 */ 6289 enum sctp_disposition sctp_sf_timer_ignore(struct net *net, 6290 const struct sctp_endpoint *ep, 6291 const struct sctp_association *asoc, 6292 const union sctp_subtype type, 6293 void *arg, 6294 struct sctp_cmd_seq *commands) 6295 { 6296 pr_debug("%s: timer %d ignored\n", __func__, type.chunk); 6297 6298 return SCTP_DISPOSITION_CONSUME; 6299 } 6300 6301 /******************************************************************** 6302 * 2nd Level Abstractions 6303 ********************************************************************/ 6304 6305 /* Pull the SACK chunk based on the SACK header. */ 6306 static struct sctp_sackhdr *sctp_sm_pull_sack(struct sctp_chunk *chunk) 6307 { 6308 struct sctp_sackhdr *sack; 6309 __u16 num_dup_tsns; 6310 unsigned int len; 6311 __u16 num_blocks; 6312 6313 /* Protect ourselves from reading too far into 6314 * the skb from a bogus sender. 6315 */ 6316 sack = (struct sctp_sackhdr *) chunk->skb->data; 6317 6318 num_blocks = ntohs(sack->num_gap_ack_blocks); 6319 num_dup_tsns = ntohs(sack->num_dup_tsns); 6320 len = sizeof(struct sctp_sackhdr); 6321 len += (num_blocks + num_dup_tsns) * sizeof(__u32); 6322 if (len > chunk->skb->len) 6323 return NULL; 6324 6325 skb_pull(chunk->skb, len); 6326 6327 return sack; 6328 } 6329 6330 /* Create an ABORT packet to be sent as a response, with the specified 6331 * error causes. 6332 */ 6333 static struct sctp_packet *sctp_abort_pkt_new( 6334 struct net *net, 6335 const struct sctp_endpoint *ep, 6336 const struct sctp_association *asoc, 6337 struct sctp_chunk *chunk, 6338 const void *payload, size_t paylen) 6339 { 6340 struct sctp_packet *packet; 6341 struct sctp_chunk *abort; 6342 6343 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6344 6345 if (packet) { 6346 /* Make an ABORT. 6347 * The T bit will be set if the asoc is NULL. 6348 */ 6349 abort = sctp_make_abort(asoc, chunk, paylen); 6350 if (!abort) { 6351 sctp_ootb_pkt_free(packet); 6352 return NULL; 6353 } 6354 6355 /* Reflect vtag if T-Bit is set */ 6356 if (sctp_test_T_bit(abort)) 6357 packet->vtag = ntohl(chunk->sctp_hdr->vtag); 6358 6359 /* Add specified error causes, i.e., payload, to the 6360 * end of the chunk. 6361 */ 6362 sctp_addto_chunk(abort, paylen, payload); 6363 6364 /* Set the skb to the belonging sock for accounting. */ 6365 abort->skb->sk = ep->base.sk; 6366 6367 sctp_packet_append_chunk(packet, abort); 6368 6369 } 6370 6371 return packet; 6372 } 6373 6374 /* Allocate a packet for responding in the OOTB conditions. */ 6375 static struct sctp_packet *sctp_ootb_pkt_new( 6376 struct net *net, 6377 const struct sctp_association *asoc, 6378 const struct sctp_chunk *chunk) 6379 { 6380 struct sctp_transport *transport; 6381 struct sctp_packet *packet; 6382 __u16 sport, dport; 6383 __u32 vtag; 6384 6385 /* Get the source and destination port from the inbound packet. */ 6386 sport = ntohs(chunk->sctp_hdr->dest); 6387 dport = ntohs(chunk->sctp_hdr->source); 6388 6389 /* The V-tag is going to be the same as the inbound packet if no 6390 * association exists, otherwise, use the peer's vtag. 6391 */ 6392 if (asoc) { 6393 /* Special case the INIT-ACK as there is no peer's vtag 6394 * yet. 6395 */ 6396 switch (chunk->chunk_hdr->type) { 6397 case SCTP_CID_INIT: 6398 case SCTP_CID_INIT_ACK: 6399 { 6400 struct sctp_initack_chunk *initack; 6401 6402 initack = (struct sctp_initack_chunk *)chunk->chunk_hdr; 6403 vtag = ntohl(initack->init_hdr.init_tag); 6404 break; 6405 } 6406 default: 6407 vtag = asoc->peer.i.init_tag; 6408 break; 6409 } 6410 } else { 6411 /* Special case the INIT and stale COOKIE_ECHO as there is no 6412 * vtag yet. 6413 */ 6414 switch (chunk->chunk_hdr->type) { 6415 case SCTP_CID_INIT: 6416 { 6417 struct sctp_init_chunk *init; 6418 6419 init = (struct sctp_init_chunk *)chunk->chunk_hdr; 6420 vtag = ntohl(init->init_hdr.init_tag); 6421 break; 6422 } 6423 default: 6424 vtag = ntohl(chunk->sctp_hdr->vtag); 6425 break; 6426 } 6427 } 6428 6429 /* Make a transport for the bucket, Eliza... */ 6430 transport = sctp_transport_new(net, sctp_source(chunk), GFP_ATOMIC); 6431 if (!transport) 6432 goto nomem; 6433 6434 transport->encap_port = SCTP_INPUT_CB(chunk->skb)->encap_port; 6435 6436 /* Cache a route for the transport with the chunk's destination as 6437 * the source address. 6438 */ 6439 sctp_transport_route(transport, (union sctp_addr *)&chunk->dest, 6440 sctp_sk(net->sctp.ctl_sock)); 6441 6442 packet = &transport->packet; 6443 sctp_packet_init(packet, transport, sport, dport); 6444 sctp_packet_config(packet, vtag, 0); 6445 6446 return packet; 6447 6448 nomem: 6449 return NULL; 6450 } 6451 6452 /* Free the packet allocated earlier for responding in the OOTB condition. */ 6453 void sctp_ootb_pkt_free(struct sctp_packet *packet) 6454 { 6455 sctp_transport_free(packet->transport); 6456 } 6457 6458 /* Send a stale cookie error when a invalid COOKIE ECHO chunk is found */ 6459 static void sctp_send_stale_cookie_err(struct net *net, 6460 const struct sctp_endpoint *ep, 6461 const struct sctp_association *asoc, 6462 const struct sctp_chunk *chunk, 6463 struct sctp_cmd_seq *commands, 6464 struct sctp_chunk *err_chunk) 6465 { 6466 struct sctp_packet *packet; 6467 6468 if (err_chunk) { 6469 packet = sctp_ootb_pkt_new(net, asoc, chunk); 6470 if (packet) { 6471 struct sctp_signed_cookie *cookie; 6472 6473 /* Override the OOTB vtag from the cookie. */ 6474 cookie = chunk->subh.cookie_hdr; 6475 packet->vtag = cookie->c.peer_vtag; 6476 6477 /* Set the skb to the belonging sock for accounting. */ 6478 err_chunk->skb->sk = ep->base.sk; 6479 sctp_packet_append_chunk(packet, err_chunk); 6480 sctp_add_cmd_sf(commands, SCTP_CMD_SEND_PKT, 6481 SCTP_PACKET(packet)); 6482 SCTP_INC_STATS(net, SCTP_MIB_OUTCTRLCHUNKS); 6483 } else 6484 sctp_chunk_free (err_chunk); 6485 } 6486 } 6487 6488 6489 /* Process a data chunk */ 6490 static int sctp_eat_data(const struct sctp_association *asoc, 6491 struct sctp_chunk *chunk, 6492 struct sctp_cmd_seq *commands) 6493 { 6494 struct sctp_tsnmap *map = (struct sctp_tsnmap *)&asoc->peer.tsn_map; 6495 struct sock *sk = asoc->base.sk; 6496 struct net *net = sock_net(sk); 6497 struct sctp_datahdr *data_hdr; 6498 struct sctp_chunk *err; 6499 enum sctp_verb deliver; 6500 size_t datalen; 6501 __u32 tsn; 6502 int tmp; 6503 6504 data_hdr = (struct sctp_datahdr *)chunk->skb->data; 6505 chunk->subh.data_hdr = data_hdr; 6506 skb_pull(chunk->skb, sctp_datahdr_len(&asoc->stream)); 6507 6508 tsn = ntohl(data_hdr->tsn); 6509 pr_debug("%s: TSN 0x%x\n", __func__, tsn); 6510 6511 /* ASSERT: Now skb->data is really the user data. */ 6512 6513 /* Process ECN based congestion. 6514 * 6515 * Since the chunk structure is reused for all chunks within 6516 * a packet, we use ecn_ce_done to track if we've already 6517 * done CE processing for this packet. 6518 * 6519 * We need to do ECN processing even if we plan to discard the 6520 * chunk later. 6521 */ 6522 6523 if (asoc->peer.ecn_capable && !chunk->ecn_ce_done) { 6524 struct sctp_af *af = SCTP_INPUT_CB(chunk->skb)->af; 6525 chunk->ecn_ce_done = 1; 6526 6527 if (af->is_ce(sctp_gso_headskb(chunk->skb))) { 6528 /* Do real work as side effect. */ 6529 sctp_add_cmd_sf(commands, SCTP_CMD_ECN_CE, 6530 SCTP_U32(tsn)); 6531 } 6532 } 6533 6534 tmp = sctp_tsnmap_check(&asoc->peer.tsn_map, tsn); 6535 if (tmp < 0) { 6536 /* The TSN is too high--silently discard the chunk and 6537 * count on it getting retransmitted later. 6538 */ 6539 if (chunk->asoc) 6540 chunk->asoc->stats.outofseqtsns++; 6541 return SCTP_IERROR_HIGH_TSN; 6542 } else if (tmp > 0) { 6543 /* This is a duplicate. Record it. */ 6544 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_DUP, SCTP_U32(tsn)); 6545 return SCTP_IERROR_DUP_TSN; 6546 } 6547 6548 /* This is a new TSN. */ 6549 6550 /* Discard if there is no room in the receive window. 6551 * Actually, allow a little bit of overflow (up to a MTU). 6552 */ 6553 datalen = ntohs(chunk->chunk_hdr->length); 6554 datalen -= sctp_datachk_len(&asoc->stream); 6555 6556 deliver = SCTP_CMD_CHUNK_ULP; 6557 6558 /* Think about partial delivery. */ 6559 if ((datalen >= asoc->rwnd) && (!asoc->ulpq.pd_mode)) { 6560 6561 /* Even if we don't accept this chunk there is 6562 * memory pressure. 6563 */ 6564 sctp_add_cmd_sf(commands, SCTP_CMD_PART_DELIVER, SCTP_NULL()); 6565 } 6566 6567 /* Spill over rwnd a little bit. Note: While allowed, this spill over 6568 * seems a bit troublesome in that frag_point varies based on 6569 * PMTU. In cases, such as loopback, this might be a rather 6570 * large spill over. 6571 */ 6572 if ((!chunk->data_accepted) && (!asoc->rwnd || asoc->rwnd_over || 6573 (datalen > asoc->rwnd + asoc->frag_point))) { 6574 6575 /* If this is the next TSN, consider reneging to make 6576 * room. Note: Playing nice with a confused sender. A 6577 * malicious sender can still eat up all our buffer 6578 * space and in the future we may want to detect and 6579 * do more drastic reneging. 6580 */ 6581 if (sctp_tsnmap_has_gap(map) && 6582 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6583 pr_debug("%s: reneging for tsn:%u\n", __func__, tsn); 6584 deliver = SCTP_CMD_RENEGE; 6585 } else { 6586 pr_debug("%s: discard tsn:%u len:%zu, rwnd:%d\n", 6587 __func__, tsn, datalen, asoc->rwnd); 6588 6589 return SCTP_IERROR_IGNORE_TSN; 6590 } 6591 } 6592 6593 /* 6594 * Also try to renege to limit our memory usage in the event that 6595 * we are under memory pressure 6596 * If we can't renege, don't worry about it, the sk_rmem_schedule 6597 * in sctp_ulpevent_make_rcvmsg will drop the frame if we grow our 6598 * memory usage too much 6599 */ 6600 if (sk_under_memory_pressure(sk)) { 6601 if (sctp_tsnmap_has_gap(map) && 6602 (sctp_tsnmap_get_ctsn(map) + 1) == tsn) { 6603 pr_debug("%s: under pressure, reneging for tsn:%u\n", 6604 __func__, tsn); 6605 deliver = SCTP_CMD_RENEGE; 6606 } 6607 } 6608 6609 /* 6610 * Section 3.3.10.9 No User Data (9) 6611 * 6612 * Cause of error 6613 * --------------- 6614 * No User Data: This error cause is returned to the originator of a 6615 * DATA chunk if a received DATA chunk has no user data. 6616 */ 6617 if (unlikely(0 == datalen)) { 6618 err = sctp_make_abort_no_data(asoc, chunk, tsn); 6619 if (err) { 6620 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6621 SCTP_CHUNK(err)); 6622 } 6623 /* We are going to ABORT, so we might as well stop 6624 * processing the rest of the chunks in the packet. 6625 */ 6626 sctp_add_cmd_sf(commands, SCTP_CMD_DISCARD_PACKET, SCTP_NULL()); 6627 sctp_add_cmd_sf(commands, SCTP_CMD_SET_SK_ERR, 6628 SCTP_ERROR(ECONNABORTED)); 6629 sctp_add_cmd_sf(commands, SCTP_CMD_ASSOC_FAILED, 6630 SCTP_PERR(SCTP_ERROR_NO_DATA)); 6631 SCTP_INC_STATS(net, SCTP_MIB_ABORTEDS); 6632 SCTP_DEC_STATS(net, SCTP_MIB_CURRESTAB); 6633 return SCTP_IERROR_NO_DATA; 6634 } 6635 6636 chunk->data_accepted = 1; 6637 6638 /* Note: Some chunks may get overcounted (if we drop) or overcounted 6639 * if we renege and the chunk arrives again. 6640 */ 6641 if (chunk->chunk_hdr->flags & SCTP_DATA_UNORDERED) { 6642 SCTP_INC_STATS(net, SCTP_MIB_INUNORDERCHUNKS); 6643 if (chunk->asoc) 6644 chunk->asoc->stats.iuodchunks++; 6645 } else { 6646 SCTP_INC_STATS(net, SCTP_MIB_INORDERCHUNKS); 6647 if (chunk->asoc) 6648 chunk->asoc->stats.iodchunks++; 6649 } 6650 6651 /* RFC 2960 6.5 Stream Identifier and Stream Sequence Number 6652 * 6653 * If an endpoint receive a DATA chunk with an invalid stream 6654 * identifier, it shall acknowledge the reception of the DATA chunk 6655 * following the normal procedure, immediately send an ERROR chunk 6656 * with cause set to "Invalid Stream Identifier" (See Section 3.3.10) 6657 * and discard the DATA chunk. 6658 */ 6659 if (ntohs(data_hdr->stream) >= asoc->stream.incnt) { 6660 /* Mark tsn as received even though we drop it */ 6661 sctp_add_cmd_sf(commands, SCTP_CMD_REPORT_TSN, SCTP_U32(tsn)); 6662 6663 err = sctp_make_op_error(asoc, chunk, SCTP_ERROR_INV_STRM, 6664 &data_hdr->stream, 6665 sizeof(data_hdr->stream), 6666 sizeof(u16)); 6667 if (err) 6668 sctp_add_cmd_sf(commands, SCTP_CMD_REPLY, 6669 SCTP_CHUNK(err)); 6670 return SCTP_IERROR_BAD_STREAM; 6671 } 6672 6673 /* Check to see if the SSN is possible for this TSN. 6674 * The biggest gap we can record is 4K wide. Since SSNs wrap 6675 * at an unsigned short, there is no way that an SSN can 6676 * wrap and for a valid TSN. We can simply check if the current 6677 * SSN is smaller then the next expected one. If it is, it wrapped 6678 * and is invalid. 6679 */ 6680 if (!asoc->stream.si->validate_data(chunk)) 6681 return SCTP_IERROR_PROTO_VIOLATION; 6682 6683 /* Send the data up to the user. Note: Schedule the 6684 * SCTP_CMD_CHUNK_ULP cmd before the SCTP_CMD_GEN_SACK, as the SACK 6685 * chunk needs the updated rwnd. 6686 */ 6687 sctp_add_cmd_sf(commands, deliver, SCTP_CHUNK(chunk)); 6688 6689 return SCTP_IERROR_NO_ERROR; 6690 } 6691